**1. Introduction**

It is ongoing research on how the food system influences safe and healthy diets and in turn helps toward maintaining a sustainable and resilient environment. The food system includes production, processing, packaging, distribution, marketing, purchasing, consumption, and waste food [1]. The food system addresses food security, food safety, and food quality. Food safety is food protection from food-borne illnesses, covers, handling, preparation, and storage of food. The quality of food provides nutritional benefits to the people. Food security includes food access during all times and under any condition. Food access becomes critical under severe climate events, natural disasters, pandemics, and political stress. These events influence access negatively which results in food insecurity.


**2.5. Gibberellins**

**2. Phytohormones signaling roles**

Abscisic acid (ABA), termed stress hormone, plays an important role in plant leaves abscis‐ sion and abiotic stresses tolerance [3]. ABA also has important roles in various plant devel‐ opmental and physiological processes such as seed dormancy, embryo morphogenesis, stomatal opening, cell turgor maintenance, and biosynthesis of lipids and storage proteins [3, 5]. ABA regulates protein‐encoding genes [6]. ABA enables plants to survive under severe environmental factors [7] and water‐deficit conditions [8]. ABA is also important for root growth and architectural modifications under nitrogen deficiency [9] and drought stress [10]. Furthermore, ABA is involved in the biosynthesis of dehydrins, osmoprotectants and protec‐

2 Phytohormones - Signaling Mechanisms and Crosstalk in Plant Development and Stress Responses

Some pathways for auxin (IAA) biosynthesis in plants have been reported so far including one tryptophan‐independent and four tryptophan‐dependent pathways [3, 13]. IAA plays an important role in plant growth and development as well as in regulating growth under stress factors [14]. IAA plays essential roles in plant adaptation to salinity [15] and heavy metal stresses [16]. Furthermore, auxins induce the transcription of the primary auxin response genes which are identified in various plants such as rice, *Arabidopsis* and soybean [3, 17].

Cytokinins (CKs) regulate plant growth and development [3, 19]. They are also involved in abiotic stresses [20] such as salinity [21] and drought [19]. They are also important for vari‐ ous crop traits such as productivity and enhanced stress tolerance [3, 22]. CKs also release seeds from dormancy [18] and are considered as abscisic acid antagonists [23]. Decreased CK content promotes apical dominance, which assists in the adaptation to drought stress [3, 20].

Ethylene (ET) is a gaseous phytohormone regulating plant growth and developmental processes, including flower senescence, fruit ripening, and petal and leaf abscission, as well as regulating stress responses [3, 24, 25]. Ethylene biosynthesis begins from methionine via S‐adenosyl‐l‐methionine and the cyclic amino acid ACC. ACC synthase converts S‐adenosyl‐l‐methionine to ACC, whereas ACC oxidase catalyzes the conversion of ACC to ET. Various abiotic stresses affect endogenous ethylene levels in plant species. Higher ET concentrations promote stress tolerance [26]. Ethylene may combine with other hormones such as jasmonates and salicylic acid and plays crucial roles in regulating plant defense against biotic stress factors [3, 1]. Ethylene and abscisic acid may act

Auxin also regulates crosstalk between biotic sand abiotic stresses [18].

together to regulate plant growth and development [3].

**2.1. Abscisic acid**

tive proteins [3, 11, 12].

**2.2. Auxins**

**2.3. Cytokinins**

**2.4. Ethylene**

Gibberellins (GAs) are carboxylic acids that may regulate plant growth and development [27]. They positively regulate leaf expansion, seed germination, stem elongation, flower develop‐ ment and trichome initiation [3, 28]. They also play important role in abiotic stress toler‐ ance [29] such as osmotic stress. GAs may interact with other hormones and regulate various developmental processes [30]. These interactions may involve both negative and positive regulatory roles [3, 30].

## **2.6. Brassinosteroids**

Brassinosteroids (BRs) comprise polyhydroxy steroidal phytohormones which regulate plant growth and developmental processes including root and stem growth, and flower initiation and development [3]. BRs were first isolated from *Brassica napus*. Brassinolide, 24‐epibrassino‐ lide, and 28‐homobrassinolide are the most bioactive BRs widely used in physiological stud‐ ies [31]. They are found in flower buds, pollen, fruits, vascular cambium, seeds, leaves, roots, and shoots [32]. BRs also play important roles in abiotic stress responses such as chilling, high temperature, soil salinity, drought, light, flooding, and organic pollutants [3].

## **2.7. Jasmonates**

Jasmonates (JAs) are multifunctional phytohormones derived from the membrane fatty acids metabolism and are widely distributed in several plant species [3]. JAs play crucial roles in growth and developmental processes such as fruiting, flowering, senescence and secondary metabolism [3, 33]. JAs are also involved in biotic and abiotic stress responses such as salin‐ ity, drought, irradiation and low temperature [3, 34]. Exogenous concentrations of methyl jasmonate (MeJA) minimize salinity stress symptoms [35]. Additionally, endogenous levels of JA are induced in roots under salinity stress [36]. JA levels also reduce heavy metal stress through inducing the antioxidant machinery [3, 37]. MeJA accumulates phytochelatins, con‐ ferring tolerance against Cu and Cd stress [38].

## **2.8. Salicylic acid**

Salicylic acid (SA) is a phenolic compound which regulates the expression of pathogenesis‐ associated proteins [39]. SA plays an important role in plant growth and development, as well as in biotic and abiotic stress responses [3, 40]. SA has two biosynthesis pathways: the major isochorismate (IC) pathway and the phenylalanine ammonia‐lyase (PAL) pathway. Low lev‐ els of SA promote the plant antioxidant capacity [3]. However, the high SA levels may result in cell death [41]. SA comprises genes encoding chaperones, antioxidants, heat shock pro‐ teins, and secondary metabolite biosynthetic genes such as cinnamyl alcohol dehydrogenase, sinapyl alcohol dehydrogenase and cytochrome P450 [3, 41]. SA may also combine with ABA to regulate drought response [39]. However, the SA mechanism in abiotic stress tolerance remains mainly unknown and still needs more investigations.

### **2.9. Strigolactones**

Strigolactones (SLs) are carotenoid‐derived compounds, produced in small quantities in roots, or synthesized in several plant species [3, 42]. SLs play an important role in root archi‐ tecture and development [43]. They induce nodulation during interaction processes [44] and may be used for inducing the parasitic plants seed germination [45]. SLs are also involved in biotic and abiotic responses [3].


**7. Time required for establishing an agricultural society: the Levant**

The regions listed in **Table 1** went on to complete the establishment of the four independent agricultural societies [28] are compared in **Table 2**. Some of the main changes to be accomplished to become an established agricultural society are listed in **Table 3**.

The independence of the four agricultures is borne out by the diversity of species involved in each case as shown in column 2. Each area developed its own distinct constellation of domesticated species. The last column gives the date at which the complex agriculture-based society appears to have been well established and shows that they were all established within the same 5-millennium time period.

Each of the changes indicated in **Tables 2** and **3** has its own problems, and the order in which they are accomplished may differ from place to place, but all of them must be carried out to complete the development of an agricultural way of life. In

**Table 2.**

*Four agricultural societies developed independently.*

#### **Table 3.**

*Main steps in transition from hunter-gatherer to agricultural societies.*

addition to the genetic changes required to produce a domesticated plant or animal, fundamental changes in technology and social structure are needed. Although the time to domesticate one particular plant may be of the order of a few centuries [19], the total time it takes to change from a hunter-gatherer society to an agricultural one is much longer. Here, we estimate this time scale for the best-studied case, the Middle East, using archeological investigations and studies of wild progenitors of cultivated plants [19]. There is also information on animal domestication that comes from bones found in archeological sites [4, 29]; housing, tool development, and settlement patterns are also available from archeological studies [4, 20]. However, much of the material from earlier archeological studies, while provocative, is of limited use because reliable dating methods are still not perfect.

The earliest agricultural society was developed in the southern Levant, an area that includes southern Syria and Lebanon, Israel, Palestine, Jordan, and the Sinai Peninsula during the cultural-historical time known as the Pre-Pottery Neolithic (PPN) that spanned the years between about 11,700 and 8250 ybp [6]. In the wellstudied Israeli section of the Levant, much of the area was an open grassland with wild cereals and pistachio trees [6]. Local Levant climate history has been derived from speleothems in Israeli caves (at 32°N) [29] that have recorded a proxy signal of the Eastern Mediterranean region. An analysis of the data since 18,000 ybp shows several markedly different climates. The most interesting time for our purposes is the ~3000-year period that has a rainfall of 675–950 mm, almost twice the presentday values, and the Dead Sea reached its maximum level. The onset of this wet episode determined within the accuracy of the time determinations corresponds to the end of the YD. After 8000 ybp, the temperature and rainfall in the Levant became more similar to the current values. The plant remains were combinations of cereals, pulses, and flax and were similar to the plants that appeared later all over

**7**

*Climate Stability and the Origin of Agriculture DOI: http://dx.doi.org/10.5772/intechopen.83344*

estimate of that date.

2000 years.

wind.

the Near East. Three cereals were cultivated: emmer wheat, einkorn wheat, and barley. Cereals alone, however, do not provide all of the nutrition required by man. In the case of the Levant, the cereals were added by legumes (lentils, peas, bitter vetch, and chickpeas) [20]. Sheep and goats were also domesticated and replace gazelles, and other wild games have previously been hunted [19]. During the PPN, the size and complexity of settlements increased by a factor of 14 [20], but the earliest of the PPN sites show some cultural continuity with the preceding final phase of the preagricultural Natufian period (12,500–12,000 ybp). The agriculture was not brought to the region by an invading force due to total absence of evidence for

interpersonal or intercommunity aggression or violence during the PPN.

The earliest evidence of cultivated cereals in the Levant has been dated to ∼ 10,600–10,000 ybp when the remains of emmer and einkorn wheats show the telltale signs of domestication. The fact that such remains were found in several sites during this period implied that the actual beginning of wheat cultivation in this area was earlier, perhaps as early as the first part of the Pre-Pottery Neolithic (PPNA) (11,700–10,500 ybp) [6]. Kislev et al. [30] presented evidence that during this same period figs appear to have been gathered from trees grown intentionally from planted branches. The development of agriculture so soon after the termination of the YD-led Bar-Yosef et al. [6] to suggest that the first experiments in systematic cultivation may have occurred during the YD which ended abruptly ~11,750 ybp. However, they report that no remains of domesticated plants have yet been recovered from the YD itself [6]. Although there is some uncertainty in the date of the beginning of wheat farming, ~11,000\$ ybp is a reasonably conservative

Thus, the development of the earliest agricultural societies would be encouraged by the absence of large century-scale climate variability during a period of at least

Here, we discuss the variations in the Earth's climate derived from two of climate proxy records (CPR): the polar ice cores in Greenland and the sea sediments from

The best and the most discussed of these data banks is from the polar ice cores in Greenland, which contains climate memory of diverse climate variables [31]. The oxygen isotopes in snow characterize temperatures [16, 32], while the dust blown from the deserts and the sea salt blown from the ocean characterize the atmospheric

The records from the Greenland Ice Sheet Project 2 (GISP2) cover the time period from 110,000 ybp to the present, although with differing sampling rates and accuracy. The variability found in these records indicates a nonlinear nature of the climate variations. For example, using a composite of the time series of the Ca, Na, Cl, SO4, K, and Mg ions and a narrowband filtering technique, Mayewski et al. [31] found that between 110,000 and 11,000 years ago there was a variation with a

To take into account the nonstationary and nonlinear character of the climate paleo records, we apply the empirical mode decomposition (EMD) techniques [33], which are especially designed for analyses of nonlinear and nonstationary time series. The EMD represents the data as the sum of a small number of empirical orthogonal modes that have time-variable amplitudes and instantaneous frequencies capturing the nonstationary spectral content of the data. This method employs empirical basis that is changing in time to adapt to the actual variability of the data

**8. When climate was stable on these time scales**

the Cariaco Basin of the Northern coast of South America.

persistent period of 1450 years but with time-varying amplitude.

#### *Climate Stability and the Origin of Agriculture DOI: http://dx.doi.org/10.5772/intechopen.83344*

*Climate Change and Agriculture*

addition to the genetic changes required to produce a domesticated plant or animal, fundamental changes in technology and social structure are needed. Although the time to domesticate one particular plant may be of the order of a few centuries [19], the total time it takes to change from a hunter-gatherer society to an agricultural one is much longer. Here, we estimate this time scale for the best-studied case, the Middle East, using archeological investigations and studies of wild progenitors of cultivated plants [19]. There is also information on animal domestication that comes from bones found in archeological sites [4, 29]; housing, tool development, and settlement patterns are also available from archeological studies [4, 20]. However, much of the material from earlier archeological studies, while provoca-

Tools Projectiles and traps Farming tools, cereal preparation, food storage

Small bands Villages, towns

**Location Species Development**

Levant Wheat, barley, chickpeas, flax, sheep, goats ~ 9000 ybp China Rice, millet, pigs, silkworms by 9000 ybp Mesoamerica Corn, beans, squash, turkey by 5500 ybp Andean-Amazonian Potato, manioc, guinea pig, llama by 5500 ybp

Domesticated counterparts

**accomplished**

techniques

**Item Hunter-gatherers Agricultural society** Food plants Wild grains, fruit, tubers Domesticated counterparts Animals Many species of wild prey A few domesticated species

Housing Temporary, easy to erect Permanent structures

*Main steps in transition from hunter-gatherer to agricultural societies.*

Clothing Wild animals, vegetable fibers

*Four agricultural societies developed independently.*

Settlement patterns

**Table 3.**

**Table 2.**

tive, is of limited use because reliable dating methods are still not perfect.

The earliest agricultural society was developed in the southern Levant, an area that includes southern Syria and Lebanon, Israel, Palestine, Jordan, and the Sinai Peninsula during the cultural-historical time known as the Pre-Pottery Neolithic (PPN) that spanned the years between about 11,700 and 8250 ybp [6]. In the wellstudied Israeli section of the Levant, much of the area was an open grassland with wild cereals and pistachio trees [6]. Local Levant climate history has been derived from speleothems in Israeli caves (at 32°N) [29] that have recorded a proxy signal of the Eastern Mediterranean region. An analysis of the data since 18,000 ybp shows several markedly different climates. The most interesting time for our purposes is the ~3000-year period that has a rainfall of 675–950 mm, almost twice the presentday values, and the Dead Sea reached its maximum level. The onset of this wet episode determined within the accuracy of the time determinations corresponds to the end of the YD. After 8000 ybp, the temperature and rainfall in the Levant became more similar to the current values. The plant remains were combinations of cereals, pulses, and flax and were similar to the plants that appeared later all over

**6**

the Near East. Three cereals were cultivated: emmer wheat, einkorn wheat, and barley. Cereals alone, however, do not provide all of the nutrition required by man. In the case of the Levant, the cereals were added by legumes (lentils, peas, bitter vetch, and chickpeas) [20]. Sheep and goats were also domesticated and replace gazelles, and other wild games have previously been hunted [19]. During the PPN, the size and complexity of settlements increased by a factor of 14 [20], but the earliest of the PPN sites show some cultural continuity with the preceding final phase of the preagricultural Natufian period (12,500–12,000 ybp). The agriculture was not brought to the region by an invading force due to total absence of evidence for interpersonal or intercommunity aggression or violence during the PPN.

The earliest evidence of cultivated cereals in the Levant has been dated to ∼ 10,600–10,000 ybp when the remains of emmer and einkorn wheats show the telltale signs of domestication. The fact that such remains were found in several sites during this period implied that the actual beginning of wheat cultivation in this area was earlier, perhaps as early as the first part of the Pre-Pottery Neolithic (PPNA) (11,700–10,500 ybp) [6]. Kislev et al. [30] presented evidence that during this same period figs appear to have been gathered from trees grown intentionally from planted branches. The development of agriculture so soon after the termination of the YD-led Bar-Yosef et al. [6] to suggest that the first experiments in systematic cultivation may have occurred during the YD which ended abruptly ~11,750 ybp. However, they report that no remains of domesticated plants have yet been recovered from the YD itself [6]. Although there is some uncertainty in the date of the beginning of wheat farming, ~11,000\$ ybp is a reasonably conservative estimate of that date.

Thus, the development of the earliest agricultural societies would be encouraged by the absence of large century-scale climate variability during a period of at least 2000 years.


*2.1. Determination of Spectral Properties*

The International Glazing DataBase (IGDB) is a collection of optical data for glazing products. Spectral transmittance and reflectance are measured in a spectrophotometer and contributed to the IGDB by the manufacturer of the glazing product, subject to a careful review. The IGDB currently only allows the inclusion of specular glazing materials without patterns, such as monolithic glass, plastic, laminates, applied films on glass, or thin-film coated glass. The products included in the WFG catalog are low-emissivity (Low-E) glass, high selective glass, and solar polyvinyl butyral (PVB) interlayers to increase sun energy absorbance. The solar energy spectrum can be divided into the ultraviolet (UV) light, visible light, and infrared (IR) light, depending on the wavelength. The wavelengths of the ultraviolet light range from 310 to 380 nanometers. The visible light ranges from 380 to 780 nanometers. The infrared light spectrum is transmitted as heat into a building and begins at wavelengths of 780 nanometers. Solar heat radiation has shortwave energy, and it is known as near-infrared (NIR), whereas the heat radiating off warm objects has higher wavelengths and is known as far-infrared (FIR). Three different WFGs were tested:

Figure 1 shows the front and back reflectance (*R*), transmittance (*T*), and absorptance (*A*), as a function of the angle of incidence. It illustrates the glass panes, coatings, and the position of the air and water chambers. Case 1 showed the highest infrared absorptance (*A*), the lowest front reflectance (*R*), and the lowest infrared transmittance (*T*). It seemed the best option to heat up water. Case 2 showed a

high near-infrared (NIR) absorptance, low far-infrared (FIR) absorptance, and high front far-infrared (FIR) reflectance. The absorptance was not as high as in Case 1, but its ability to reflect heat made it the right solution for large glass areas in warm climates. Case 3 showed very low infrared absorptance and very high infrared front reflectance. This case would have been the best option to reject energy and prevent heat from entering the indoor space, but it would not have been appropriate to heat up water.

**Figure 1.** Spectral properties as a function of the solar wavelength. Description of the layers and coatings. (**a**) Case 1: 8 + 8/24 w /8 + 8/16 a /6 + 6. (**b**) Case 2: 10/16 a/Low-E8 + 8/24 w/8 + 8. (**c**) Case 3: 10XNII/16 a/8 + 8/24 w/8 + 8.


**1. Introduction**

Oxysterols, formed either enzymatically or by auto-oxidation, have a second oxygen function in addition to that of C-3 when compared with natural sterols. These compounds are of particular interest due to important biological functions of some of them and various bioactivities, including effects on lipid metabolism, platelet aggregation, apoptosis, different receptors and proteins [1]. Generally, oxysterols attract a great attention by the contribution to many physiological processes, including those connected with pathophysiology of the neurodegenerative diseases [2]. As a key trend, the roles of two brain sterols, 24*S*-hydroxycholesterol and 27-hydroxycholesterol, have been studied for years and discussed in multiple reports [3–5]. Among others, 24*S*-hydroxycholesterol has been reported to be markedly reduced in the circulation of patients with Parkinson's disease (PD) [4]. The treatment with 27-hydroxycholesterol or a combination of 24*S*-hydroxycholesterol and 27-hydroxycholesterol reduced the levels of noradrenaline, whereas the treatment with 24*S*-hydroxycholesterol alone had no effect. With these results, the authors demonstrated that oxysterols could regulate the proteins involved in the development of PD [5].

Recently, some other oxysterols were found to be exported from the brain: 7β-hydroxycholesterol, 7-ketocholesterol, 3β,5α-dihydroxycholestan-6-one, 7α-hydroxy-3-oxocholest-4-enoic acid, 7α,25-dihydroxycholest-4-en-3-one, and (25*R*)-7α,26-dihydroxycholest-4-en-3-one. It was underlined that these transfers were observed when total oxysterols were measured [6,7]. These facts give a new quest to disclose possible roles and bioactivities of non-common oxysterols, including those of marine origin, in development of PD and other neurodegenerative diseases.

Recent studies highlighted the point that even well-known oxygenated sterols might be a critical source of new medicine leads. Thus, hecogenin and cholest-4-en-3-one showed significant inhibitory activity (EC50 values of 116.3 and 390.6 μM, respectively) against the human β-site amyloid cleaving enzyme (BACE1), which has been considered as an effective drug target for treatment of Alzheimer's disease [8].

The search for new oxysterols in marine organisms and the studies on their action in model cell systems could be also considered as an approach to the creation of new pharmaceutical leads against neurodegenerative diseases. As a part of our chemical investigations of steroidal compounds from marine sponges [9–11], we have studied oxysterols of a cold-water marine sponge *Inflatella* sp. The sponges belonging to the genus *Inflatella* are insufficiently studied for their secondary metabolites, though some bioactivities of their extracts were noted [12]. The ethanol extract of the studied *Inflatella* sp. sample was preliminary analyzed by thin-layer chromatography during the screening of sponge samples from PIBOC collection. The results revealed that in contrast with extracts of other sponges, it contained the oxygenated steroids visually detected on chromatograms as a number of bright colored spots (Figure S1). Herein we describe the isolation and structural elucidation of fourteen individual oxysterols of *Inflatella* sp., including four new compounds as well as the results of their biotesting using a cell model of PD. Part of this work has been presented at the 3rd International Symposium on Life Sciences, Vladivostok, Russia, September 2018.


**9. Conclusion**

PBDEs were widely used as flame retardants. Due to their effects as endocrine disruptors, neurotoxins, and on reproductive capacity as well, knowledge of terrestrial accumulation behavior and, in particular, their uptake by plants for food production is highly relevant. Uptake can occur viasoil-air-plant pathway as well as soil–soil water-root-plant pathway. Transport and plant uptake behavior strongly depend on physical and chemical properties of the BDEs, environmental factors, large-scale atmospheric transport processes, plant properties as well as terrestrial rhizospheres. During both atmospheric and terrestrial transport PBDEs are subject to UV-induced (atmospheric) or microbial induced (terrestrial) transformation

**79**

*Plant Uptake, Translocation and Metabolism of PBDEs in Plants*

and degradation processes like debromination, hydroxylation, methoxylation and ring closure to dibenzofurans. As PBDEs reveal high lipophilicity they tend to adsorption on lipophilic soil matrices and thereby show low uptake via soil–soil water-root-plant pathway and subsequent intrinsic transport. Hence, uptake and intrinsic transport are only expected for low brominated BDEs. Therefore, declining concentrations of PBDEs could be detected from soil via roots to shoots and final fruits, i.e. RCF and TF show negative correlation with their log KOW values. Consistent with this statement, 84% of the human PBDE intake are attributed to respiration and inhalation of dust, while only 16% were correlated with dietary uptake. The actual exposure of vegetarian foods to PBDEs depends on the follow-

• Both microbial degradation and plant uptake of PBDE are elevated by release of easily biodegradable plant extracts like amino acids, organic acids, sugars

• The presence of rhizobia enhances microbial degradation and plant uptake of

• Both atmospheric and terrestrial PBDE uptakes are strongly affected by the morphology of the plant (specific surface of leaves and roots) and the increas-

• PBDE immobilization and accumulation in soil is promoted by increasing TOC levels caused by implementation of compost, sewage sludge, digestates, or

• In contrast, increasing levels of DOC show no effect on plant uptake of PBDEs

• As sewage sludge shows PBDE contamination up to 2.5 w%, it is an important emission source of PBDEs affecting soil contamination. In contrast, PBDE loads of compost and digestates are very low and commonly pollution effects

• A decrease in evaporation losses and an enhanced immobilization tendency of

• Solubilizers, ionic additives and nanoscale organic substances act as mobilizing

• Macroelements as nitrate favor terrestrial PBDE degradation through its func-

• The presence of trace elements supports microbial transformation of PBDE in soil and therefore causes lower contamination of plants. In contrast, heavy metals seem to enforce PBDE uptake by plants by inhibition of terrestrial

• Current mathematical models allow high quality in prediction of the RCF value with a minimum of input parameters. In opposite, the prediction of SCF and TF values is not suitable due to the insufficient coverage of plant-specific

tion as alternative electron acceptor. Hence, plant's load is reduced.

and exoenzymes as commonly observed in symbiosis with rhizobia.

ing lipid content of plant tissues accelerating PBDE uptake.

as long as there is no solubilizing effect by surfactants.

PBDE can be observed in case of raising soil moisture.

agents increasing mobilization and plant uptake of PBDEs.

*DOI: http://dx.doi.org/10.5772/intechopen.95790*

ing parameters:

PBDE.

biochar.

are negligible.

biodegradation processes.

parameters.


2.2.11. House of Al-Sinnar¯ ¯ı (1794)

At the House of Al-Sinnar¯ ¯ı, a large wooden canopy facing north constitutes the roof of the small *Iwan* south of the main *qa'a* (Figure 17). The northern and western openings are provided with frames with glazed windows. The *qa'a* has an unusual layout with the artificial separation established between this southern *Iwan* and the *durqa'a* using a high grille with a *Mashrabiya* (decorative projective windows prominent in Islamic architecture). This grille allows air to circulate from the windcatcher, through the *Iwan*, toward the dome on an openwork drum of the *durqa'a*. Dominated by the *malqaf*, this small *Iwan* appears as an independent room, which also acts as an antechamber [19].

**Figure 17.** (**a**) An inside view of the windcatcher in the House of Al-Sinnar¯ ¯ı. (**b**) An outside view of the windcatcher, the arrow signifies the air flow to the windcatcher (modified by the authors; based on [17]).

2.2.12. The Palace of Al-Jawhara in the Citadel (1814–1829)

All that seems to be left of Muhammad Ali's Palace's ventilation system is the single windcatcher shown in Figure 18 [12]. The awning of the windcatcher is on the ceiling of the central room, which connects to the peripheral rooms as well as the access staircase and the two sanitary and service blocks [19].

**Figure 18.** (**a**) Plan for the Palace of al-Jawhara showing the location of the windcatcher (modified by the authors based on; [19]). (**b**) The northeastern elevation of the windcatcher, the arrows signify the air flow to the windcatcher (modified by the authors based on [19]).

#### *2.3. Modern Era in Egypt: Hassan Fathy's Designs, AUC Towers, and Sixth of October Villas*

Hassan Fathy and Ramsis Wissa Wassef were the most broadly known pioneer architects who revived vernacular architecture that used domes, vaults, and windcatchers. Hassan Fathy used the windcatchers in residential and public buildings such as the primary school for girls in El Gourna Village, where all the classes have an adjacent windcatcher facing north, from which the wind flows in and exits from another opening above the room. Placed inside the windcatcher of El Gourna is a sloped metal tray filled with wetted charcoal over which the air flows to cool the building. This object is similar to the *salsabil* that was used in the *Iwans* and halls of old Arab homes. Consequently, the windcatcher used in Gourna reduced the classroom's temperature by 10 degrees [15].