1.3: The Formal Criminal Justice Process
The Formal Criminal Justice Process [13]
Components of Criminal Justice
Most of these criminal justice systems consist of five components- law enforcement, prosecution, defense attorneys, courts, and corrections. Each of these play a unique but critical role in criminal justice proceedings.
Law enforcement officers are tasked with hearing and investigating reports for crimes which happen in their jurisdiction. These officers investigate crimes by gathering and protecting evidence, making arrests, providing testimony during court processes, and conducting follow-up investigations as needed.
After law enforcement officers investigate a criminal offense, it is up to the prosecution to represent the state or federal government throughout the court process. Prosecutors must review the evidence gathered by officers and determine whether to file formal charges against the suspect or to drop the case. They are also tasked with presenting the evidence in court, questioning witnesses, determining what charges a suspect will be charged with, and more.
While the prosecution represents the state or federal government, it is the job of defense attorneys to represent the individuals accused of a criminal offense. They can either be hired by the defendant themselves or assigned by the court since legal representation is a basic right outlined in the Constitution.
Both the prosecution and defense attorneys are involved in the courts which are run by judges. Their role is to ensure that the law is followed along with overseeing what happens in court. Judges are able to determine whether or not to release offenders before a trial, accept or reject plea agreements, oversee trials, and sentence individuals convicted of illegal acts. Judges are easily some of the most powerful individuals in the criminal justice system.
Finally, after an individual has been investigated, tried, convicted, and sentenced, they enter the last criminal justice component of corrections including jails and prisons. These terms are often used interchangeably, but in reality, jails are used to house individuals sentenced to less than one year of incarceration as well as those awaiting trial, while prisons house individuals sentenced to be incarcerated for a year or more. Correction officers are tasked with supervising convicted individuals in jail or prison, and also include probation (jail) and parole (prison) officers who are responsible for monitoring these individuals either after they have completed their sentence or in some cases in lieu of incarceration. Corrections officers typically prepare pre-sentencing reports on the individual which are used to help judges decide on sentences as well as overseeing the day-to-day custody of incarcerated inmates (NCVC, 2008a).
Initial Contact [15]
Initial contact is the step in which the police takes some action against the suspected perpetrator. The police contact the suspect and inform him/her about the violation he/she has committed. Making initial contact, investigating crimes, apprehending offenders/potential offenders (arrest), and booking them in the local jail all happens after the officer has made initial contact. Making initial contact does not mean that the suspect has actually committed the crime; law enforcement does not determine guilt or innocence, hand down punishments, or implement the punishment.
During an investigation, police officers may need to obtain a search warrant. The Fourth Amendment of the Constitution requires that police officers have probable cause before they search a person’s home, their clothing, car, or other property, with some exceptions explored later on. In order to ensure due process, searches usually require a search warrant, issued by a “neutral and detached” judge. Arrests also require probable cause and often occur after police have gotten an arrest warrant from a judge. Depending on the specific facts of the case, the first step may be an arrest. As stated above, if they catch a person in the commission of a crime, they will arrest first and investigate later.
Investigation [17]
“For the court to be satisfied that the investigator acted lawfully and within the bounds of legally prescribed authority, the judge needs to hear the investigator describe their thinking processes to form reasonable grounds, or in some emergency cases, to have a reasonable suspicion that justifies the action taken.”
An effective strategy for learning any new skill is to define it and break it down into logical steps, establishing a progression that can be followed and repeated to reach the desired results. The process of investigation is no exception and can be effectively explained and learned in this manner. In this chapter, you will learn how each of the following issues relates to the process of investigation.
- The distinction between investigative tasks and investigative thinking
- The progression of the investigative process
- The distinction between tactical investigative and strategic investigative responses
- The concepts of event classification and offence recognition
- The threat vs. action response dilemma
- The distinction between active events and inactive events
- The connection of active events and Level 1 priority results to the powers afforded under exigent circumstance
- The Response Transition Matrix (RTM) and the critical need to transition from tactical response to strategic response
Topic 1: The Distinction Between Investigative Tasks and Investigative Thinking
To understand the process of investigation, it is necessary to comprehend the distinction between investigative tasks and investigative thinking. Investigative tasks relate to the information gathering processes that feed into investigative thinking and the results. Investigative thinking, on the other hand, is the process of analyzing information and theorizing to develop investigative plans. Let us consider this distinction in a little more depth.
Investigative Tasks
Investigative tasks relate to identifying physical evidence, gathering information, evidence collection, evidence protection, witness interviewing, and suspect interviewing and interrogation. These are essential tasks that must be learned and practiced with a high degree of skill to feed the maximum amount of accurate information into the investigative thinking process. Criminal investigation is aimed at collecting, validating, and preserving information in support of the investigative thinking process. Accordingly, it is important to learn to do these evidence collection tasks well.
Investigative Thinking
Investigative thinking is aimed at analyzing the information collected, developing theories of what happened, the way an event occurred, and establishing reasonable grounds to believe. Those reasonable grounds to believe will identify suspects and lead to arrest and charges. Investigative thinking is the process of analyzing evidence and information, considering alternate possibilities to establish the way an event occurred and to determine if they are reasonable.
Topic 2: Progression of the Investigative Process
The investigative process is a progression of activities or steps moving from evidence gathering tasks, to information analysis, to theory development and validation, to forming reasonable ground to believe, and finally to the arrest and charge of a suspect. Knowing these steps can be helpful because criminal incidents are dynamic and unpredictable. The order in which events take place, and the way evidence and information become available for collection, can be unpredictable. Thus, only flexible general rules to structured responses can be applied. However, no matter how events unfold or when the evidence and information are received, certain steps need to be followed. These include collection, analysis, theory development and validation, suspect identification and forming reasonable grounds, and taking action to arrest, search, and lay charges.
In any case, as unpredictable as criminal events may be, the results police investigators aim for are always the same. And you should always keep the desired results in mind to provide focus and priority to the overall investigative process. We will talk more later in this book about developing a mental map of the investigative process to assist in recording, reporting, and recounting events. It is mentioned now because a mental map is an appropriate metaphor to illustrate the investigative thinking process.
In this process, even though the path we will take to investigate may be unclear and unpredictable at first, the destination, the results we seek in our investigation , will always be the same and can be expressed in terms of results and their priorities .
Results and priorities focus first on the protection of the lives and safety of people. They focus second on the priorities of protecting property, gathering and preserving evidence, accurately documenting the event, and establishing reasonable grounds to identify and arrest offenders.
Priorities refer to Level One Priorities, as the protection of the lives and safety of people. This includes the protection and safety of the police officer’s own life and the life and safety of other officers.
The Level Two priorities are the four remaining aforementioned results, and these may be considered equal value to each other. Depending on circumstances, a rationale can be made for choosing to concentrate on one Level Two priority at the expense of another depending on the circumstances presenting.
The critical point to be made here is that under no circumstances should an investigator ever choose to focus his or her efforts and attention to a Level Two priority if doing so would compromise the Level One priority of protecting the life and safety of a person, including police officers themselves. In the event that evidence is lost or destroyed, or that a suspect is not identified or apprehended because investigators were taking care of the Level One priority, that is a justifiable outcome. A response that would sacrifice the safety of people to achieve a level two priority would not be justifiable and could even lead to civil or criminal outcomes against the investigators making such a choice.
Now that we have looked at the critical aspects of investigative tasks and the response priorities police investigators need to apply to decision making when they take action, we can proceed to examine the two different types of investigative response. We will refer to these as the Tactical Investigative Response and the Strategic Investigative Response .
Topic 3: Distinction Between a Tactical Investigative Response and a Strategic Investigative Response
These two different types of investigative responses are defined by the nature and status of the event that the investigator is facing. If it is an active event, it will require a Tactical Investigative Response and if it is an inactive event it will require a Strategic Investigative Response. It is important for an investigator to understand these two different levels of response because they include different response protocols, different legal authorities, and limitations to authority.
Tactical Investigative Response
Tactical Investigative Response is faced by operational officers who are engaged in the frontline response to criminal events. As mentioned earlier, police are often challenged to respond to events, sometimes life and death situations, where information is limited, and critical decisions need to be made to take action. In these Tactical Investigative Responses, the responding officers often have little or no time to undertake the tasks of gathering information. They must rely on the information of a dispatched complaint, coupled with their own observations made once they arrive at the scene. If an officer takes the action of making an arrest or using force to bring the situation under control, they are accountable for the action they have taken, and they may be called upon by the court to articulate their thinking, albeit based on limited information.
Strategic Investigative Response
Once an investigator has arrived at the scene of an event and has brought the event under control by either making an arrest or by determining that the suspect has fled the scene and no longer poses a threat to the life or safety of persons, the investigation becomes a strategic investigative response. With this expiration of life and safety issues, also comes the expiration of exigent circumstances and the additional authorities to detain persons suspected and to enter and search private property without a warrant.
Clearly understanding and being able to define and articulate the circumstances of either an active event and tactical response, or a controlled event and a strategic response is critical. In court, it becomes important for a police investigator to describe what they were told going into the complaint, what they saw and heard when they arrived at the complaint, and, most importantly, what they were thinking to justify the action that was taken. For the court to be satisfied that the investigator acted lawfully, the judge needs to hear the investigator describe their thinking process to form reasonable grounds, or in some emergency cases, to have a reasonable suspicion that justifies the action taken.
To properly articulate their thinking in these investigative responses, it is important for the officer to understand the situational elements that can help define their thinking process when they testify in court. Two of the most important situational elements to understand are event classification and offence recognition .
Topic 4: Event Classification and Offence Recognition
In order to enter any investigation in either the tactical or the strategic response mode, an investigator must engage their thinking processes and make decisions about the event they are confronting. Is it an active event in progress that requires immediate and decisive tactical actions; or is it an inactive event where a less urgent, slower, and more strategic approach can be taken? This slower and more considered approach is the strategic investigative response, and the situational elements of this approach will be discussed in detail later in this chapter. Thinking about these situational elements of active event or inactive event is call event classification.
Considering the possible crime being committed in the event is called “offence recognition,” and this recognition of a specific offence activates the investigator’s thinking to look for the evidence that supports the elements of that recognized offence.
Topic 5: Classifying the Event as Either an Active Event or an Inactive Event
For each of these classifications of active event or inactive event , the investigator has some different legal authorities to put into action, as well as some immediate responsibilities for the protection, collection, and preservation of evidence. When attending the scene of any reported event, the investigator should assume that the event is active until it has been established to be inactive.
In many cases, an event can be re-classified as an inactive event when it is determined that the suspect has left the scene of the event, or the event has concluded by the suspect being arrested. In cases where the suspect is still at the scene of an active event, the investigator needs to be thinking about the possibility of detaining the suspect or making an arrest of that suspect for an offence in progress. To make that detention or arrest, the investigator should be thinking about what possible offence they are being called to investigate by the initial complaint, and also by the evidence they are seeing and hearing upon arrival.
The classification of active event or inactive event is critical. It is a distinction that will guide an officer to determine what powers of detention, arrest, use of force, entry to property, and search may be relied upon to take action. The defining elements between active event and inactive event are:
An Active Event
- The criminal act is or may still be in progress at the scene.
- The suspect is or may still be at the scene of the event.
- The situation is, or may be, a danger to the life or safety of a person, including the life or safety of attending police officers.
An Inactive Event
- The criminal act has concluded at the scene.
- The suspect or suspects have left the scene or have been arrested or detained.
- The situation at the scene no longer represents a danger to the life or safety of a person, including police officers.
Topic 6: Threat vs. Action Analysis Dilemma
The critical elements of this Threat vs. Action Analysis Dilemma were demonstrated in what became known as “Active Shooter calls” flowing from the incident at Columbine High School in 1999 (Police Executive Research Forum, 2014). In this incident, two armed teenagers went on a shooting spree in the high school killing 13 people and wounding 20 others before turning their weapons on themselves and committing suicide. Officers responding to that call followed departmental protocols of that era. These protocols dictated they should wait for the arrival of their Emergency Response Team in events where armed suspect confrontations were taking place. The fact that these first responders waited despite ongoing killing taking place inside the high school led to a determination that police have a duty to take action in such cases, and waiting is not the correct response. As a result of these determinations, active shooter response protocols were adopted across North America and police agencies re-trained their personnel to respond to active shooters with more immediate action and strategies to enter and confront the shooters in order to protect lives of possible victims.
The Threat vs. Action Analysis Dilemma response protocols in the active shooter response situations now provide the standard or benchmark that a responding officer must consider when faced with the decision to enter a dangerous situation alone and take action, or to wait for back-up before entering to take action. For active shooter situations, the protocols across North America are now prescribed responses, where responding officers are trained to enter and confront with minimal back-up. That said, not every potentially dangerous Threat vs. Action Analysis Dilemma is going to be an active shooter. Responding officers will often be faced with other calls where danger exists to the safety of persons and the decision to enter or wait for back-up must still be made. In these cases, the responding officer must weigh the available information and respond or wait for back-up per their own threat vs risk assessment of the facts. The active shooter protocols have provided something of a calibration to this analysis where extreme ongoing threat to life and safety of person equals high duty and high expectation to take action.
Topic 7: Rules of Engagement for an Active Event or an Inactive Event
Police officers may be called to action by many different means. It may be a radio dispatch 911 call to attend an emergency, a citizen flagging down the passing police car to report an incident, or an officer coming upon a crime in progress. Whatever the means of being called to action, this is the first step of the police officer becoming engaged in a thinking process to gather and evaluate information, make decisions, and take action. The first step of this thinking process for the investigator is to make the evaluation and ask the questions:
- Is this an Active Event requiring a Tactical Investigative Response?
- Is this an Inactive Event requiring a Strategic Investigative Response?
As a subsequent part of this evaluation determining an Active Event or Inactive Event, the investigator should also be alert to the type crime being encountered. For example, is it an assault, a robbery, or a theft? From the perspective of police tactical investigative response, an investigator confronted with an active event must first assess the threat level. Is there a danger to the life or safety of persons that would require a Level One Priority Result , taking immediate action to protect life and safety of persons, including the life and safety of attending police officers?
In assessing these threat levels to life and safety, police are often faced with very limited information. Sometimes there is only a possible threat, or an implied threat to the life or safety of persons. In such cases, it is only necessary for the police to suspect that there is a threat to the life or safety of a person to evoke the extended powers provided by exigent circumstances. In these cases of implied threats, police are authorized to rely on the powers afforded by exigent circumstances to enter private property without a warrant and to detain and search suspects who may present a danger. These are significant powers, and an investigator must be aware that if they use these powers, there is a strong possibility they will later be called upon to justify the exercise of those power.
An officer desiring to conduct a search needs probable cause for the search to be lawful. Because society expects police officers to find evidence and arrest criminals, they may be overzealous in determining whether they do or do not have probable cause. Generally, the evidence establishing probable cause must be submitted to an impartial magistrate , and if the magistrate agrees that probable cause exists, then he or she will issue a search warrant .
Scenario #1
A uniform patrol officer receives a call to attend a complaint through radio dispatch. The 911 caller is reporting that he has just witnessed his neighbor punch his wife in the front yard and then drag her forcibly into their house. The responding officer is immediately able to classify this event as an active event . The officer’s offence recognition of the criminal act is that it is likely an assault and possibly a forcible confinement. Given this assessment, the situation requires a Tactical Investigative Response . The suspect is still at the scene and there is an ongoing possibility of danger to the life or safety of the suspect’s wife. In this type of case, the officer can draw upon the extended powers under exigent circumstances to ensure the safety of the wife. Considering the information that has been reported, the officer may go to the residence with a view to using the necessary force to enter without a warrant to investigate the safety and well-being of the identified victim. If, after entering the home, further investigation provides evidence to confirm an assault, the officer can arrest the identified suspect for that offence. In this scenario, the information that allows the classification of the active event and the offence recognition is fairly clear in the reported circumstances.
Scenario #2
Sometimes an event cannot be immediately classified as either an active event or an inactive event. In these cases, where the information is less clear, the investigator may be justified to assume an ongoing danger to the life or safety of persons and remain in the tactical investigative response mode utilizing the powers afforded under exigent circumstances to pursue the investigation until it is determined that an implied danger no longer exists. For example, consider the situation where police dispatch receives a 911 call from a woman crying. Before any further information can be obtained from the caller, the call is terminated from the caller’s end. A patrol unit is dispatched to attend the residential address associated with the identified phone number. Upon arrival at the front door of the caller’s address, attending officers are met by a male resident of the home who identifies himself as the homeowner. The attending officers advise the male that a terminated 911 call from a crying woman was received from this address. The male states that there is nothing wrong in his home and he refuses to allow officers to enter the premises. The officers advise the male that they need to enter the premises to satisfy themselves that there is no ongoing threat to the life or safety of the crying woman caller. The officers warn the man that they will be entering the premises and if he resists, he will be arrested for obstructing a police officer.
The man steps aside and the officers enter the home and find a woman in the bedroom area with a bleeding nose and a bruised face. The woman tells officers that the male, her husband, punched her in the face during an argument and when she attempted to call police, he ripped the phone cord from the wall and struck her again. She states that he threatened to kill her if she cried out when the police came to the door. The man is arrested for assault, forcible confinement, and uttering threats. He is provided with his Charter Rights and warning, and he is then asked if he wishes to make any statement.
To evaluate this scenario, the officers had very little information in the first instance that would allow them to make a determination of active event or inactive event. The information to identify a criminal act was equally limited. Fortunately, case law has evolved to recognize this kind of information-limited case, and it provides a framework for making a response that can protect life and safety. In such situations, an officer is still empowered to act under the authority of “exigent circumstances.” Considering information-limited circumstances like this, the officer only needs to have a suspicion that there is a threat to the life or safety of a person to act. That threat may be simply implied by the circumstances being presented. In this case, the implied threat to life or safety of a person was the disconnected 911 call. The officers had a duty to attend and resolve the possible threat to life or safety of a person implied in this disconnected 911 call ( R v Godoy , 1999).
As you might imagine, an officer attending the calls outlined in the preceding scenarios needs to be very clear on the circumstances where implicit distress and exigent circumstances can be interpreted to use the powers to enter private property. This same need extends to using appropriate levels of force and making an arrest. Considering these are active and still evolving criminal events, there is urgency to act. It is critical for the investigating officer to have a clear understanding of these principles to quickly assess the presented facts, make the event classification, and take the necessary action in an expedient manner.
As outlined earlier in this book, there is a significant difference between reasonable grounds to believe and reasonable grounds to suspect, and an officer who is not clear on the distinction might have a difficult time articulating to the court how and why they took the initiative to act or not to act. It is these types of cases, where there is implied distress, or an implied threat to life or safety, that an investigator must be clear on their interpretation of the event and on their authorities to take action. The thinking involved might be described as an active event and an explicit or implied threat to life or safety equals exigent circumstances.
More on Offence Recognition
At the same time the event is being classified as either active event or inactive event, the investigator should be engaging in the thinking process of offence recognition. In other words, what offence is being reported or what is the offence being observed in the fact pattern that is unfolding? With this offence recognition, the investigator will begin to assemble a mental inventory of the evidence and information that will be required to support the recognized offence(s). Having an offence in mind, the investigator will also begin to consider their range of powers and authorities that can be used under the law regarding that offence. The investigator will ask themself
- Is this a summary conviction offence where the suspect must be found committing to justify an arrest?
- Or, is it an indictable or dual procedure offence where there is direct evidence or strong circumstantial evidence to support an arrest?
If the investigator determines that they are attending to an Active Event and their offence recognition suggests that there may be a danger to the life or safety of a person, such as assault causing bodily harm, they will know that they need only find evidence to form reasonable grounds to believe in order to make an arrest. As part of attendance to the scene of the event, the investigator should be classifying the location to determine what their legal requirements are for their authority to enter. Consideration of the possible authorities to enter private property would include:
- Consent of the property owner
- Section 487 CCC warrant to search
- Exigent circumstances to suspect a need to protect the life or safety of a person
- Exigent circumstance with reasonable grounds to believe there will be a destruction of evidence of an indictable offence
- Fresh pursuit of a suspect found committing an offence
If the investigator arrives at the scene where a suspect is immediately apparent, the investigator can make an immediate detention or perhaps even an arrest. The investigator may rely on the Section 529 (2) of the Criminal Code of Canada (1985) under exigent circumstance to enter private property without a warrant to make the arrest and ensure the safety of persons at the scene. If the investigator makes an arrest after forming reasonable grounds for belief, they are required by the Canadian Charter of Rights and Freedoms to tell the suspect what offence they are being arrested for.
Required Warnings
The following is the standard Charter of Rights (Canadian Charter, 1982, s 10(a,b)) warning and police warning. These standard caution warnings are given as follows:
I am arresting you (or detaining you) for [name of offence(s)].
POLICE WARNING
I wish to give you the following warning: You need not say anything. You have nothing to hope from any promise or favor, and nothing to fear from any threat whether or not you do say anything. Anything you do or say may be used as evidence.
 (Transit Police, 2015)
CHARTER WARNING
You have the right to retain and instruct counsel without delay. You also have the right to free and immediate legal advice from duty counsel by making free telephone calls to [toll-free phone number(s)] during business hours and [toll-free phone number(s)] during non-business hours.

Do you wish to call a lawyer?
You also have the right to apply for legal assistance through the provincial legal aid program.
 (Transit Police, 2015)
Let us consider the following scenario to illustrate these principles in action.
Scenario #3
An officer is dispatched to attend the complaint of an assault with a weapon and determines that it is taking place in a residential dwelling house in a nearby subdivision. Upon arrival, the officer is met on the front lawn by a man claiming to have witnessed the owner of the home stab a visitor to the home during an altercation as a second male runs out the front door holding his side and bleeding from an apparent wound.  The officer directs the man with the knife to drop it on the ground and step out of the residence. The man complies and is arrested for assault with a weapon.
From this fact pattern the investigator could make an immediate arrest for assault with a weapon. The investigator would seize the bloody knife and protect it as evidence of that offence. The facts within this scenario that allow the investigator to take action, enter the private property, and form their reasonable grounds for belief and make the arrest. When the case goes to court, the investigator of this case will articulate the chain of events along with their thinking to substantiate their reasonable grounds for belief. To achieve this, the investigator’s testimony would be that:
- they were dispatched to attend a complaint of assault with a weapon in progress,
- the suspect was still on scene and it was an active event,
- considering the potential danger to life or safety of a person, they entered the property under the provisions of exigent circumstances,
- an independent witness at the scene stated the homeowner had stabbed a guest in the home,
- a man bleeding from an apparent wound ran from the home, and
- another man standing in the doorway was holding a bloody knife and was identified by the witness as the homeowner.
The investigating officer arriving at the scene of this event would treat this as a Level One priority because there is an ongoing danger to the life and safety of persons. Under these circumstances, the Criminal Code authorities of exigent circumstances would apply. The investigator would be justified in detaining all parties present, including the witness and the victim, on the reasonable suspicion that they may all have been involved in combative behavior and might each still pose a threat to the life and safety of others, including the investigator. The powers of exigent circumstances are significant in this kind of scenario and provide authority to take immediate action that will neutralize threats to the safety of people. Even if the facts of this assault with a weapon had evolved to show that it was taking place inside the private home of the suspect with the bloody knife, the authority of exigent circumstances would permit the investigator to enter that home without a warrant to protect the life and safety of persons. A very significant point to be made here is that as soon as the event is under control the extended powers of exigent circumstances expire.
Once this event has been brought under control and the threat to the life or safety of persons had been eliminated by arresting or detaining all persons present, the investigator must reclassify this event as an inactive event. As soon as this occurs, some of the rules of engagement and legal authorities to take action change, and the investigation must switch to a Strategic Investigative Response.
With the expiry of exigent circumstances and the switch to a Strategic Investigative Response, several factors change. If this assault with a weapon had been taking place in the suspect’s private home, and the investigator had entered under the authority of exigent circumstance, the authority to remain in the private residence and search it would expire. If the investigator needed to collect additional physical evidence in that home, such as blood from the stabbing assault, a warrant or consent to search would now be required.
In this type of case, the residence of the suspect could be locked down externally and all persons removed until a search warrant was obtained to complete the investigation. Evidence obtained up to the point where the arrest was made and before exigent circumstances expired would be lawfully seized without a warrant.  Anything else searched for and seized after the arrest could be challenged as an unlawful seizure if it was taken without a search warrant.
In addition to the requirement for search warrants, in some cases after exigent circumstances expire, other priorities and investigative must also change. As you will recall, the protection of life and safety of people is the Level One priority. With that priority, the court allows significant leeway to investigators in regard to the protection of crime scenes and the collection of evidence. If an investigator is attending any criminal event, the protection and collection of evidence always takes a backseat to the protection of life or safety of people. That said, once the life and safety issues have been resolved, the securing of the crime scene and the subsequent protection and collection of evidence becomes the number one priority.
Once the life and safety issues are resolved, it is time to lock down the crime scene and start protecting evidence for court. If it is possible to protect the life and safety of people and collect, protect, and preserve evidence, this is the preferred outcome. If it is not possible, the court will accept the fact that damage to evidence occurred prior to life and safety issues being resolved. Once those issues are resolved, the expectation is that a high level of care will be taken. If proper care is not taken, and evidence becomes contaminated, or continuity of possession is lost, the evidence may be ruled inadmissible at a trial. It is important for the investigator to fully grasp the construct that dictates when to transition from Tactical Investigative Response to Strategic Investigative Response.
Topic 8: Response Transition Matrix (RTM)
The RTM is a matrix tool to illustrate the considerations for police response when considering the authorities and issues to escalate or de-escalate from a Tactical Investigative Response to Strategic Investigative Response. Considering the following questions will help an investigator to identify an event as either a Tactical Investigative Response or a Strategic Investigative Response:
- Is the event active or inactive?
- What offence(s) is possibly occurring?
- Do I suspect an implicit or explicit danger to the life or safety of a person?
- Do I have reasonable grounds to believe evidence of an indictable offence will be lost or destroyed?
- What immediate actions can be taken to protect the life or safety of persons?
- What immediate action can be taken to protect evidence, without compromising life or safety?
- Have life and safety issues been resolved, and should the change be made from Tactical Investigative Response to Strategic Investigative Response?
For example, in the Canadian justice system, both statutory law and case law have evolved to establish a range of authorities and police powers that allow rapid response at the more dangerous end of the matrix, and more time-consuming restrictions to act at the less threatening end of the matrix. The chart below illustrates the duty to act, the authority to act, and the priorities for action to consider.
Figure 1.14 The RTM Matrix [20]
Summary
In this chapter, we have discussed the progression of the investigative process and the key elements within the progression that must be considered by an investigator. These elements within the investigative process are the signposts on the roadway of a mental map. These signposts of active event or inactive event tell us to either take action within the extended authorities of exigent circumstances or to modify our response for an inactive event and recognize the need to make the transition to a strategic response. An investigator’s understanding of the changes in circumstances that define these situations and the change from active to inactive events can make the difference between successful and unsuccessful investigative outcomes.
Study Questions
- What is the difference between investigative tasks and investigative thinking?
- What is the difference between Level One Priorities and Level Two Priorities?
- What is the difference between a Tactical Investigative Response and a Strategic Investigative Response?
- What is the difference between an active event and an inactive event?
- When would an investigator consider the Threat vs. Action Analysis Dilemma?
- When does an investigator have the authority to enter a dwelling house without a warrant?
- Why is it important for an investigator to thinking about “offence recognition” at the same time they are thinking about whether a situation should be classified as an active event or an inactive event?
- What is the Response Transition Matrix (RTM)?


17.2: Reaction Rates Typically Change with Time
Make sure you thoroughly understand the following essential ideas which have been presented above. It is especially imortant that you know the precise meanings of all the green-highlighted terms in the context of this topic.
- Describe the contrasting roles of thermodynamics and kinetics in understanding chemical change.
- Given a balanced net equation, write an expression for the rate of a reaction .
- Sketch a curve showing how the instantaneous rate of a reaction might change with time.
- Determine the order of a reaction of the form A → B + C from experimental data for the concentrations of its products at successive times.
- Describe the initial rate and isolation methods of determining the orders of the individual reactants in a reaction involving multiple reactants.
- Explain the difference between differential and integral rate laws .
- Sketch out a plot showing how the concentration of a component ([A] or ln [A]) that follows first-order kinetics will change with time. Indicate how the magnitude of the rate constant affects this plot
- Define the half-life of a reaction.
- Given the half-life for a first-order reaction A → products along with the initial value of [A] o , find [A] t at a subsequent time an integral number of half-lifes later.
- Describe the conditions under which a reaction can appear to have an order of zero.
On this page we extend the concept of differential rate laws introduced on the previous page to integral rate laws and reaction half-life that are of great importance in most practical applications of kinetics.
Differential and integral rate laws
Measuring instantaneous rates as we have described on the previous page of this unit is the most direct way of determining the rate law of a reaction, but is not always convenient, and it may not even be possible to do so with any precision.
- If the reaction is very fast, its rate may change more rapidly than the time required to measure it; the reaction may be finished before even an initial rate can be observed.
- In the case of very slow reactions, observable changes in concentratons occur so slowly that the observation of a truly "instantaneous" rate becomes impractical.
The ordinary rate law (more precisely known as the instantaneous or differential rate law) tells us how the rate of a reaction depends on the concentrations of the reactants. But for many practical purposes, it is more important to know how the concentrations of reactants ( and of products ) change with time. For example, if you are carrying out a reaction on an industrial scale, you would want to know how long it will take for, say, 95% of the reactants to be converted into products.
This is the purpose of an integrated rate law .
Integrating the rate law
This is easy to do, but only some courses expect you to know how to do it. For a quick run-through, click here . If you have had even a bit of calculus, here is an opportunity to put it to use!
Expressing the "speed" of a reaction: the half-life
How long does it take for a chemical reaction to occur under a given set of conditions? As with many "simple" questions, no meaningful answer can be given without being more precise. In this case,
How do we define the point at which the reaction is "completed"?
A reaction is "completed" when it has reached equilibrium — that is, when concentrations of the reactants and products are no longer changing. If the equilibrium constant is quite large, then the answer reduces to a simpler form: the reaction is completed when the concentration of a reactant falls to zero. In the interest of simplicity, we will assume that this is the case in the remainder of this discussion.
"How long?" may be too long
If the reaction takes place very slowly, the time it takes for every last reactant molecule to disappear may be too long for the answer to be practical. In this case, it might make more sense to define "completed" when a reactant concentration has fallen to some arbitrary fraction of its initial value — 90%, 70%, or even only 20%.
The particular fraction one selects depends on the cost of the reactants in relation to the value of the products, balanced against the cost of operating the process for a longer time or the inconvenience of waiting for more product. This kind of consideration is especially imporant in industrial processes in which the balances of these costs affect the profitability of the operation.
The half-life of a reaction
Instead of trying to identify the time required for the reaction to become completed, it is far more practical to specify the the time required for the concentration of a reactant to fall to half of its initial value. This is known as the half-life (or half-time) of the reaction.
First-order reactions
The law of exponential change
The rate at which a reactant is consumed in a first-order process is proportional to its concentration at that time. This general relationship, in which a quantity changes at a rate that depends on its instantaneous value , is said to follow an exponential law .
Exponential relations are widespread in science and in many other fields. Consumption of a chemical reactant or the decay of a radioactive isotope follow the exponential decay law. Its inverse, the law of exponential growth, describes the manner in which the money in a continuously-compounding bank account grows with time, or the population growth of a colony of reproducing organisms.
The reason that the exponential function y=e x so efficiently describes such changes stems from the remarkable property that dy/dx = e x ; that is, e x is its own derivative, so the rate of change of y is identical to its value at any point. A nice discussion of this property can be found here .
The first-order integrated rate law
The integrated rate law for a first-order reaction
A → products
is a common example of the law of exponential change. For a reactant A, its concentration [A] t at time t is given by
[A] t = [A] o × e – kt
in which [A] o is its initial concentration and k is the first-order rate constant.
The "e" in the exponential term is of course the base of the natural logarithms, and the negative sign in its exponent means that the value of this term diminishes as t increases, as we would expect for any kind of a decay process.
A more convenient form of the integrated rate law is obtained by taking the natural logarithm of both sides:
ln [A] = – kt + ln [A] o (4-1)
This has the form of an equation for a straight line
y = mx + b
in which the slope m corresponds to the rate constant k . This means that, for a first-order reaction, a plot of ln [A] as a function of time gives a straight line with a slope of – k .
Half-life
After a period of one half-life, t = t ½ and we can write
\[\dfrac{[\mathrm{A}]_{1 / 2}}{[\mathrm{~A}]_0}=\dfrac{1}{2}=\mathrm{e}^{-k t_{1 / 2}} \nonumber \]
(in which we express the exponential as a function in order to make it stand out more prominently.) Taking logarithms of both sides (remember that
ln e
x
=
x
) yields
\[\ln 0.5=-k t \nonumber \]
Solving for the half-life, we obtain the simple relation
\[t_{1 / 2}=\dfrac{0.693}{k} \nonumber \]
which tells us that the half-life of a first-order reaction is a constant . This means that 100,000 molecules of a reactant will be reduced to 50,000 in the same time interval needed for ten molcules to be reduced to five.
It should be clear that the rate constant and the half life of a first-order process are inversely related.
The half-life of a first-order reaction was found to be 10 min at a certain temperature. What is its rate constant in reciprocal seconds?
Solution:
From the above equation, k = –0.693/(600 s) = 0.00115 s –1
The decay of radioactive nuclei is always a first-order process.
The mass-241 isotope of americium, widely used as an ionizing source in smoke detectors, has a half-life of 432 years.
a) What fraction of the Am 241 in a smoke detector will have decayed after 50 years?
b) How long will it take for the activity to decline to 80% of its initial value?
c) What would be the "seventh-life" of Am 241 ?
Second-order reactions
Integration of the second-order rate law
\[-\dfrac{d[\mathrm{~A}]}{d t}=-k|\mathrm{~A}|^2 \nonumber \]
yields
\[-\dfrac{1}{\mid \mathrm{A}]}=\dfrac{1}{\left|\mathrm{~A}_{\mathrm{o}}\right|}+k t \nonumber \]
which is easily rearranged into a form of the equation for a straight line (try showing this yourself!) and yields plots similar to the one shown on the left below.
The half-life is given by
\[t_{1/2}=\dfrac{1}{k\left|\mathrm{~A}_0\right|} \nonumber \]
(see here for details)
Notice that the half-life of a second-order reaction depends on the initial concentration, in contrast to its constancy for a first-order reaction. For this reason, the concept of half-life for a second-order reaction is far less useful.
Zero-order processes
In some reactions, the rate is apparently independent of the reactant concentraton, in which case
Integration of the differential rate law yields [A] t = [A] 0 – k
\[rate =k[\mathrm{~A}]^0=k \nonumber \]
Note the word "apparently" in the preceding sentence; zero-order kinetics is always an artifact of the conditions under which the reaction is carried out. For this reason, reactions that follow zero-order kinetics are often referred to as pseudo-zero-order reactions.
Clearly, a zero-order process cannot continue after a reactant has been exhausted. Just before this point is reached, the reaction will revert to another rate law instead of falling directly to zero as depicted at the upper left.
There are two general conditions that can give rise to zero-order rates:
This situation commonly occurs when a reaction is catalyzed by attachment to a solid surface ( heterogeneous catalysis ) or to an enzyme.
For example, the decomposition of nitrous oxide
N 2 O (g) → N 2 (g) + ½ O 2 (g)
in the presence of a hot platinum wire (which acts as a catalyst) is zero-order, but it follows more conventional kinetics when carried out entirely in the gas phase.
In this case, the N 2 O molecules that react are limited to those that have attached themselves to the surface of the solid catalyst. Once all of the sites on the limited surface of the catalyst have been occupied, additional gas-phase molecules must wait until the decomposition of one of the adsorbed molecules frees up a surface site.
Enzyme-catalyzed reactions in organisms begin with the attachment of the substrate to the active site on the enzyme, leading to the formation of an enzyme-substrate complex . If the number of enzyme molecules is limited in relation to substrate molecules, then the reaction may appear to be zero-order.
This is most often seen when two or more reactants are involved. Thus if the reaction
A + B → products
is first-order in both reactants so that
rate = k [A][B]
then if B is present in great excess, the reaction will appear to be zero order in B (and first order overall). This commonly happens when B is H 2 O and the reaction is carried out in aqueous solution.
- Only a small fraction of the reactant molecules are in a location or state in which they are able to react, and this fraction is continually replenished from the larger pool.
- When two or more reactants are involved, the concentrations of some are much greater than those of others
Summary
The following table compares the rate parameters of zero-, first-, and second-order reactions of the form a A → products . See also this excellent page from Purdue University that shows plots of [A], ln [A], and 1/[A] for each reaction order.
| zero order | first order | second order | |
|---|---|---|---|
| differential rate law | rate = k | rate = k [A] | rate = k [A] 2 |
| integrated rate law | \([A]=[A]_0=-a k t\) | \(\ln \dfrac{[\mathrm{A}]_0}{[\mathrm{~A}]}=a k t\) | \(\dfrac{1}{[\mathrm{~A}]}-\dfrac{1}{[\mathrm{~A}]_0}=a k t\) |
| half-life | \(\dfrac{[\mathrm{A}]_0}{2 a k}\) | \(\frac{\ln 2}{a k}=\frac{.693}{a k}\) | \(\frac{1}{a k[\mathrm{~A}]_0}\) |
| plot that gives straight line | [A] vs. t | ln [A] vs. t | 1/[A] vs. t |
| plot, showing interpretation of slope and intercept |


1.10.7: Fitness- Optional Continued Learning
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The videos below provide an opportunity to expand on your learning from the chapter. As you watch the video, make a list of what you notice and what you wonder. This is a great strategy to listen purposefully, engage with the content, and look for deeper opportunities for self growth, self-reflection, and learning.
What do you notice ?
- How does this topic support, expand, or challenge the content in the chapter?
- How does this topic connect to health topics from other chapters?
- How does this topic connect with your prior learning, your experiences, your work, your family, or your life in general?
- How does this topic help you to more fully understand health and wellness?
What do you wonder ?
- How has this topic sparked your curiosity?
- What would you like to know more about?
- What questions did you have as you reviewed the topic?
- What other popular and scholarly sources support or refute this topic?
Videos for continued learning and application
Note: These videos are intended to more fully reflect on health. You might agree or disagree with the videos and that is ok! Utilize these videos to critically think through the topics and identify other sources, both scholarly and popular, to convey your learning.
6 tips for better sleep
A walk through the stages of sleep
Got a meeting? Take a walk
How daylight saving time affects our bodies, minds — and world
How do steroids affect your muscles— and the rest of your body?
How much sleep do you really need?
Physical therapy is boring — play a game instead
The benefits of good posture
The brain-changing benefits of exercise
The surprising reason our muscles get tired
What makes muscles grow?
What yoga does to your body and brain
Why do we dream?
Why sitting is bad for you


40.12: Blood Flow and Blood Pressure Regulation - Blood Flow Through the Body
- Explain the blood flow through the body
How Blood Flows Through the Body
As the heart pumps, blood is pushed through the body through the entire circulatory system. Oxygenated blood is pumped away from the heart to the rest of the body, while deoxygenated blood is pumped to the lungs where it is reoxygenated before returning to the heart.
Blood Flow Away from the Heart
With each rhythmic pump of the heart, blood is pushed under high pressure and velocity away from the heart, initially along the main artery, the aorta. In the aorta, the blood travels at 30 cm/sec. From the aorta, blood flows into the arteries and arterioles and, ultimately, to the capillary beds. As it reaches the capillary beds, the rate of flow is dramatically (one-thousand times) slower than the rate of flow in the aorta. While the diameter of each individual arteriole and capillary is far narrower than the diameter of the aorta, the rate is actually slower due to the overall diameter of all the combined capillaries being far greater than the diameter of the individual aorta.
The slow rate of travel through the capillary beds, which reach almost every cell in the body, assists with gas (especially oxygen and carbon dioxide) and nutrient exchange. Blood flow through the capillary beds is regulated depending on the body’s needs and is directed by nerve and hormone signals. For example, after a large meal, most of the blood is diverted to the stomach by vasodilation (widening) of vessels of the digestive system and vasoconstriction (narrowing) of other vessels. During exercise, blood is diverted to the skeletal muscles through vasodilation, while blood to the digestive system would be lessened through vasoconstriction. The blood entering some capillary beds is controlled by small muscles called precapillary sphincters. A sphincter is a ringlike band of muscle that surrounds a bodily opening, constricting and relaxing as required for normal physiological functioning. If the precapillary sphincters are open, the blood will flow into the associated branches of the capillary bed. If all of the sphincters are closed, then the blood will flow directly from the arteriole to the venule through the thoroughfare channel. These muscles allow the body to precisely control when capillary beds receive blood flow. At any given moment, only about 5-10 percent of our capillary beds actually have blood flowing through them.
Blood Flow to the Heart
After the blood has passed through the capillary beds, it enters the venules, veins, and finally the two main venae cavae (singular, vena cava) that take blood back to the heart. The flow rate increases again, but is still much slower than the initial rate in the aorta. Blood primarily moves in the veins by the rhythmic movement of smooth muscle in the vessel wall and by the action of the skeletal muscle as the body moves. Because most veins must move blood against the pull of gravity, blood is prevented from flowing backward in the veins by one-way valves. Thus, because skeletal muscle contraction aids in venous blood flow, it is important to get up and move frequently after long periods of sitting so that blood will not pool in the extremities.
Key Points
- As blood is pumped away from the heart, it travels through the aorta to arteries, aterioles, and the capillary beds.
- Blood flow through the capillary beds reaches almost every cell in the body and is controlled to divert blood according to the body’s needs.
- After oxygen is removed from the blood, the deoxygenated blood flows to the lungs, where it is reoxygenated and sent through the veins back to the heart.
Key Terms
- arteriole : one of the small branches of an artery, especially one that connects with capillaries
- vein : a blood vessel that transports blood from the capillaries back to the heart
- artery : an efferent blood vessel from the heart, conveying blood away from the heart regardless of oxygenation status
- vena cava : either of the two large veins that take oxygen depleted blood from the upper body and lower body and return it to the right atrium of the heart


<IP_ADDRESS>: Flour Streams and Types of Wheat Flour
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Flour Streams and Types of Wheat Flour
Modern milling procedures produce many different flour streams (approximately 25) that vary in quality and chemical analysis. These are combined into four basic streams of edible flour, with four other streams going to feed.
- Top patent flour: This stream is composed of only the purest and most highly refined streams from the mill. It is low in ash and is approximately 50% of the flour extracted. The term ash indicates the mineral content (e.g., phosphorus) of the flour. When flour is burned, all that is left is the burned mineral elements that constitute ash.
- Second patent flour: This flour is composed of streams with an intermediate degree of refinement. It has an average ash content of approximately 0.45% and represents about 35% of the total flour.
- First clear flour: This stream contains the balance of the flour that possesses baking properties, and is high in ash and protein content. It is usually about 15% of the total flour.
- Second clear flour: This grade contains the poorest flour streams. It is very high in ash (approximately 0.75%), and has little or no baking quality. It is about 2% of the total flour.
- Feed streams: The balance of the streams from the mill are classed as feed. Feeds are marketed as bran, wheat shorts , flour middlings, and wheat germ.
Within the streams of edible flours, there are a number of different types of flour used in food preparation. Each has different characteristics, and with those come different uses, as described below.
All-Purpose Flour
General purpose or home use flours are usually a blend of hard spring wheats that are lower in protein (gluten) content than bread flours. They are top patent flours and contain sufficient protein to make good yeast breads, yet not too much for good quick breads, cakes, and cookies.
Note: A word about gluten quality as opposed to gluten quantity: The fact that a particular flour contains a high quantity of protein, say 13% to 15%, does not necessarily mean that it is of high quality. It may contain too much ash or too much damaged starch to warrant this classification. High quality is more important in many bread applications than high quantity. All-purpose flour is an example of a high-quality flour, with a protein content of about 12%.
Graham Flour
A U.S. patented flour, graham flour is a combination of whole wheat flour (slightly coarser), with added bran and other constituents of the wheat kernel.
Bread Flour
Bread flour is milled from blends of hard spring and hard winter wheat. They average about 13% protein and are slightly granular to the touch. This type of flour is sold chiefly to bakers because it makes excellent bread with bakery equipment but has too much protein to be considered all-purpose. It is also called strong flour or hard flour.
Cake Flour
Cake flour is milled from soft wheat. The protein content is about 7% and the granulation is so uniform and fine that the flour feels satiny. An exception is a high-protein cake flour formulated especially for fruited pound cakes (to prevent the fruit from sinking).
Clear Flour
Clear flour comes from the part of the wheat berry just under the outer covering. Comparing it to first patent flour is like comparing cream to skim milk. It is dark in color and has a very high gluten content. It is used in rye and other breads requiring extra strength.
Gluten Flour
Gluten flour is made from wheat flour by removing a large part of the starch. It contains no more than 10% moisture and no more than 44% starch.
Pastry Flour
Pastry flour is made from either hard or soft wheat, but more often from soft. It is fairly low in protein and is finely milled, but not so fine as cake flour. It is unsuitable for yeast bread but ideal for cakes, pastries, cookies, and quick bread.
Self-Rising Flour
Self-rising flour has leavening and salt added to it in controlled amounts at the mill.
Wheat Germ Flour
Wheat germ flour consists entirely of the little germ or embryo part of the wheat separated from the rest of the kernel and flattened into flakes. This flour should be refrigerated.
Whole Wheat Flour
Whole wheat flour contains all the natural parts of the wheat kernel up to 95% of the total weight of the wheat. It contains more protein than all-purpose flour and produces heavier products because of the bran particles.
Whole Wheat Pastry Flour
Whole wheat pastry flour is milled from the entire kernel of soft wheat, is low in gluten, and is suitable for pastries, cakes, and cookies.
Triticale Flour
The world’s first new grain, triticale is a hybrid of wheat and rye. It combines the best qualities of both grains.
Semolina
Semolina is the granular product consisting of small fragments of the endosperm of the durum wheat kernel (The equivalent particles from other hard wheat are called farina ).
Blending Flours
The blending of flours is done at the mill, and such is the sophistication of the analysis and testing of flours (test baking, etc.) that when problems occur it is generally the fault of the baker and not the product. Today the millers and their chemists ensure that bakers receive the high grade of flour that they need to produce marketable products for a quality-conscious consumer. Due to the vagaries of the weather and its effect on growing conditions, the quality of the grain that comes into the mill is hardly ever constant. For example, if damp weather occurs at harvest time, the grain may start to sprout and will cause what is known as damaged starch . Through analysis and adjustments in grain handling and blending, the miller is able to furnish a fairly constant product.
Bakers do blend flours, however. A portion of soft flour may be blended with the bread flour to reduce the toughness of a Danish pastry or sweet dough, for example. Gluten flour is commonly used in multi-grain bread to boost the aeration.


<IP_ADDRESS>: Formal Charge and Oxidation State (Problems)
PROBLEM \(\PageIndex{1}\)
Determine the formal charge and oxidation state of each element in the following:
a. HCl
b. CF
4
c. PCl
3
- Answer a
-
FC: H: 0, Cl: 0
OX: H: +1, Cl: -1
- Answer b
-
FC: C: 0, F: 0
OX: C: +4, F: -1
- Answer c
-
FC: P: 0, Cl: 0
OX: P: +3, Cl: -1
PROBLEM \(\PageIndex{2}\)
Determine the formal charge and oxidation state of each element in the following:
a. H
3
O
+
b. \(\ce{SO4^2-}\)
c. NH
3
d. \(\ce{O2^2-}\)
e. H
2
O
2
- Answer a
-
FC: H: 0, O: +1
OX: H: +1, O: -2
- Answer b
-
FC: S: +2, O: -1
OX: S: +6, O: -2
- Answer c
-
FC: N: 0, H: 0
OX: N: -3, H: +1
- Answer d
-
FC: -1
OX: -1
- Answer e
-
FC: O: 0, H: 0
OX: O: -1, H: +1
- Click here to see a video of the solution
PROBLEM \(\PageIndex{3}\)
Calculate the formal charge and oxidation state of chlorine in the molecules Cl 2 and CCl4.
- Answer
-
FC: Cl in Cl 2 : 0; Cl in CCl 4 : 0
OX: Cl in Cl 2 : 0; Cl in CCl 4 : -1
PROBLEM \(\PageIndex{4}\)
Calculate the formal charge and oxidation state of each element in the following compounds and ions:
a. F
2
CO
b. NO
–
c. \(\ce{BF4-}\)
d. \(\ce{SnCl3-}\)
e. H
2
CCH
2
f. \(\ce{PO4^3-}\)
- Answer a
-
FC: C: 0, F :0, O: 0
OX: C: +4, F: -1, O: -2
- Answer b
-
FC: N: -1, O: 0
OX: N: +1, O: -2
- Answer c
-
FC: B: -1, F: 0
OX: B: +3, F: -1
- Answer d
-
FC: Sn: -1; Cl: 0
OX: Sn: +2, Cl: -1
- Answer e
-
FC: C: 0, H: 0
OX: C: -2, H: +1
- Answer f
-
FC: P: +1, O: -1
OX: P: +5, O: -2
PROBLEM \(\PageIndex{5}\)
Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in nitrosyl chloride: ClNO or ClON?
- Answer
-
ClNO
- Click here to see a video of the solution
PROBLEM \(\PageIndex{6}\)
Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in hypochlorous acid: HOCl or OClH?
- Answer
-
HOCl
PROBLEM \(\PageIndex{7}\)
Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in sulfur dioxide: OSO or SOO?
- Answer
-
OSO
- Click here to see a video of the solution
PROBLEM \(\PageIndex{8}\)
Draw the structure of hydroxylamine, H 3 NO, and assign formal charges; look up the structure. Is the actual structure consistent with the formal charges?
- Answer
-
The structure that gives zero formal charges is consistent with the actual structure:
PROBLEM \(\PageIndex{9}\)
Which of the following structures would we expect for nitrous acid? Determine the formal charges:
- Answer
-
The first structure is the best structure. the formal charges are closest to 0 (and also the second structure does not give a complete octet on N)
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Contributors and Attributions
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Paul Flowers (University of North Carolina - Pembroke), Klaus Theopold (University of Delaware) and Richard Langley (Stephen F. Austin State University) with contributing authors. Textbook content produced by OpenStax College is licensed under a Creative Commons Attribution License 4.0 license. Download for free at<EMAIL_ADDRESS>).
- Adelaide Clark, Oregon Institute of Technology


8.7: Practice Session #3
For this practice session, use only the timer and note cards. Start the timer, and just as with session #2, deliver the speech solely from the note cards. During this session, speakers should pretend they have an audience and interact with them during delivery instead of the note cards.
Note to Self
The more speakers push themselves to get away from the notes and use them only when they forget what to say next, the more they will learn the speech and give off the impression of credibility, preparedness, and confidence.
During this third practice session, consider incorporating one or more of the following techniques:
- Deliver the speech to a test audience of family or friends . Hearing feedback from familiar faces can offer perspectives that may help identify problem points.
- Deliver the speech in front of a full-length mirror without looking away. This helps to desensitize the part of the emotional brain (the limbic system) that controls the natural aversion to eye contact. This exercise helps build confidence to maintain eye contact with audience members.
- Record the delivery of the speech using a phone, camera, or webcam and watch it for self-review. As uncomfortable as this feels, it provides truly valuable feedback, leading to greater development as a speaker.
Following the techniques outlined for these three practice sessions will provide speakers with a good starting point with which to work. Some people may require more practice, while others may be able to get by with less, but this much is certain: Practice makes perfect and helps the speakers develop confidence in their abilities to deliver a credible message to the audience.


6.7B: Gemeinschaft and Gesellschaft
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Introduced by German sociologist Ferdinand Tönnies, Gemeinschaft and Gesellschaft are two conceptual models for types of human association.
Learning Objectives
- Explain how status is achieved in Gemeinschaft and Gesellschaft respectively
Key Points
- Gemeinschaft and Gesellschaft are sociological categories, introduced by the German sociologist Ferdinand Tönnies, which describe two common kinds of human groupings or association.
- Gemeinschaft (” community “) is an association in which individuals are oriented to the larger group as much as, and often more than, their own self interest, and are further regulated by common social mores or beliefs about the appropriate behavior and responsibility of members of the association.
- Gesellschaft (” society “) describes associations in which, for the individual, the larger association never takes precedence over their own self interest, and these associations lack the same level of shared social mores as Gemeinschaft.
Key Terms
- association : A group of persons associated for a common purpose; an organization; society.
- kinship : relation or connection by blood, marriage, or adoption
Introduced by German sociologist Ferdinand Tönnies, Gemeinschaft and Gesellschaft are two conceptual models for types of human association.
Gemeinschaft
Gemeinschaft (“community”) is an association in which individuals are mainly oriented to the will of the larger group, generally more than their own self-interest. Their activities are regulated by common mores or beliefs about the appropriate behavior and responsibilities of members of the association. These associations are marked by what Tönnies called “unity of will. ” He saw the family as the most perfect expression of Gemeinschaft; however, he also expected that Gemeinschaft could be based on shared place and shared belief as well as kinship, and included globally dispersed religious communities as possible examples of Gemeinschaft.
Gemeinschaft community involves ascribed status, meaning a fixed status given by birth. For example, an individual born from farmers will come to occupy their parents’ role until death. Gemeinschaften (“communities”) are broadly characterized by a moderate division of labor, strong personal relationships, strong families, and relatively simple social institutions. In such societies, there is less of a need to enforce social control externally due to a collective sense of loyalty individuals feel for society.
Gesellschaft
In contrast, Gesellschaft (“society”) describes associations in which the larger association never takes precedence over the individual’s self interest, and these associations lack the same level of shared social mores. Gesellschaft is maintained through individuals acting on their own self-interest. A modern business is a good example of Gesellschaft: the workers, managers, and owners may have very little in terms of shared orientations or beliefs, or they may not care deeply for the product they are making, but it is in all their self interest to come to work to make money, and, therefore, the business continues.
Gesellschaft society involves achieved status, or a status reached by education and professional advancement. Unlike Gemeinschaften (“communities”), Gesellschaften (“societies”) emphasize secondary relationships rather than familial or community ties, and there is generally less individual loyalty to the larger community. Social cohesion in Gesellschaften typically derives from a more elaborate division of labor. Such societies are, therefore, potentially more susceptible to class conflict, as well as racial and ethnic conflicts.
As all conceptual models, these categories can be challenged by social change. For instance, during the social upheavals of the Reconstruction era in the United States, former slaves, whose kinship ties were forcibly disrupted under slavery, forged new communities that shared aspects of both Gemeinschaft and Gesellschaft. A current example of a Gemeinschaft community would be the Amish, whereas the United States would be considered a Gesellschaft society.


19.2C: Lymph Transport
Lymph circulates to the lymph node via afferent lymphatic vessels and drains into the lymph node in the subcapsular sinus.
- Describe the location of B cells and T cells in lymph nodes and the path of lymph circulation
Key Points
- The sinus space is crisscrossed by the pseudopods of macrophages, which act to trap foreign particles and filter the lymph.
- Lymph then leaves the lymph node via the efferent lymphatic vessel towards either a more central lymph node or for drainage into a central venous subclavian blood vessel.
- Lymphatic transport begins in the lymphatic capillaries, which converge into collecting vessels that flow into afferent vessels, then into lymph nodes.
- The lymph fluid leaves the node through efferent lymph vessels, which converge into lymphatic trunks, which in turn converge into one of the lymphatic ducts that flow lymph back into venous circulation.
- B and T lymphocytes must be transported to different sites within lymph nodes during an adaptive immune response.
Key Terms
- afferent lymphatic vessels : These vessels enter into the lymph nodes, flowing into the sinus space below the capsule of the node.
- lymph : A colorless, watery bodily fluid carried by the lymphatic system, consisting mainly of white blood cells.
- germinal centers : Places within secondary lymph nodes to which B cells migrate to proliferate and differentiate based on an antigen response.
Lymph transport refers to the transport of lymph fluid from the interstitial space inside the tissues of the body, through the lymph nodes, and into lymph ducts that return the fluid to venous circulation.
Transport in the Lymph Capillaries and Vessels
Lymphatic capillaries are the site of lymph fluid collection from the tissues. The fluid accumulates in the interstitial space inside tissues after leaking out through the cardiovascular capillaries. The fluid enters the lymphatic capillaries by leaking through the minivalves located in the junctions of the endothelium. Under ordinary conditions these minivalves prevent the lymph from flowing back into the tissues. In addition to interstitial fluid, pathogens, proteins, and tumor cells may also leak into the lymph capillaries and be transported through lymph.
The lymph capillaries feed into larger lymph vessels. The lymph vessels that receive lymph fluid from many capillaries are called collecting vessels. Semilunar valves work together with smooth muscle contractions and skeletal muscle pressure to slowly push the lymph fluid forward while the valves prevent backflow. The collecting vessels typically transport lymph fluid either into lymph nodes or lymph trunks.
Transport Within Lymph Nodes
Lymph circulates to the lymph node via afferent lymphatic vessels. The lymph fluid drains into the node just beneath the capsule of the node into its various sinus spaces. These spaces are loosely separated by walls, so lymph fluid flows around them throughout the lymph node.
The sinus space is filled with macrophages that engulf foreign particles and pathogens and filter the lymph. The sinuses converge at the hilum of the node, where lymph then leaves the node via an efferent lymphatic vessel toward either a more central lymph node or a lymph duct for drainage into one of the subclavian veins.
The lymph nodes contain a large number of B and T lymphocytes, which are transported throughout the node during many components of the adaptive immune response. When a lymphocyte is presented with an antigen (such as by an activated helper T cell), B cells become activated and migrate to the germinal centers of the node, where they proliferate and differentiate to be specific to that antigen. When antibody-producing B cells are formed, they migrate to the medullary (central) cords of the node. Stimulation of the lymphocytes by antigens can accelerate the migration process to about ten times normal, resulting in the characteristic swelling of the lymph nodes that is a common symptom of many infections. The lymphocytes are transported through lymph fluid and leave the node through the efferent vessels to travel to other parts of the body to perform adaptive immune response functions.
Flow of Lymph : The lymph flows from the afferent vessels into the sinuses of the lymph node, and then out of the node through the efferent vessels.
The End of Lymphatic Transport
After leaving the lymph node through efferent vessels, lymph travels either to another node further into the body or to a lymph trunk, the larger vessel where many efferent vessels converge. Four pairs of lymph trunks are distributed laterally around the center of the body, along with an unpaired intestinal trunk.
The lymph trunks then converge into the two lymph ducts, the right lymph duct and the thoracic duct. These ducts take the lymph into the right and left subclavian veins, which flow into the vena cava. This is where lymph fluid reaches the end of its journey from the interstitial space of tissues back into blood circulation.


4.1: Understanding Sex and Gender
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Although the terms sex and gender are sometimes used interchangeably and do in fact complement each other, they nonetheless refer to different aspects of what it means to be a woman or man in any society.
Sex refers to the anatomical and other biological differences between females and males that are determined at the moment of conception and develop in the womb and throughout childhood and adolescence. Females, of course, have two X chromosomes, while males have one X chromosome and one Y chromosome. From this basic genetic difference spring other biological differences.
 Scholars generally regard gender as a social construct, meaning that it doesn’t exist naturally but is instead a concept that is created by cultural and societal norms. From birth, children are socialized to conform to certain gender roles based on their biological sex and the gender to which they are assigned.[1]
[1] Intersex by Wikipedia is licensed under CC BY-SA 3.0