 have seen repression. But not Cuba. Because of Fidel and revolutionary socialist leadership, because the Revolution has the support of the masses, because the Revolution and the people are one, Cuba survived this dire period.
Fidel’s leadership was central to Cuba’s struggle for the return of the child Elián González. In 1999, Elián’s mother misguidedly took her child with her on the seas in an attempt to get to Florida. She sadly died in that voyage. But Elián survived and was kidnapped by hostile counterrevolutionary forces and taken to Miami. All of Cuba mobilized to make the U.S. return Elián home to his father — and to the Revolution. And Cuba won!
The Cuban people and their leadership focused on freeing the Cuban Five, anti-terrorists who sacrificed much to monitor hostile military actions conducted in Florida against Cuba. The U.S. imprisoned the Five in 2001 for a decade and a half. But free them the Revolution did. And home they went.
Under Fidel’s leadership, Cuba’s role in support for Haiti, in liberation struggles in Africa, more recently in fighting Ebola, are only a few stellar examples of Cuba’s internationalism. As Cuba’s president, Fidel’s call for cancellation of capitalist debts owed by oppressed nations, and his constant attention to climate change, are more examples of his exemplary leadership.
We must study Fidel so that we can live like Fidel. These words from his May Day 2000 speech, words Fidel lived every moment of his life, tell us why:
.”
We have been so fortunate to be alive at the same time as Fidel. To have lived in the same time as Fidel is the same as the honor to have lived in the time of Lenin.
Let us take the responsibility right now, from now on, and commit ourselves to be like Fidel, live like Fidel, fight like Fidel!
Long live the Cuban Revolution! VIVA FIDEL! VIVA RAÚL!
WE ARE ALL FIDEL! SOCIALISM OR DEATH!
¡FIDEL PRESENTE! ¡FIDEL PRESENTE! ¡FIDEL PRESENTE!
¡Hasta la victoria siempre Fidel!Natural/synthetic rubber blend adhesive offers excellent holding at both room temperature and at a higher bake oven temperature. Adhesion to steel 36 oz. per inch of width. Tensile strength 30 lbs. per inch of width. Elongation at break 10%. Temperature range 300 F. for 30 minutes.On 26 October 2012, the Education Development Unit hosted the second annual Health Education Research Day in the Faculty of Health Sciences (FHS). The welcome address was made by the Deputy Dean of Undergraduate Education, Professor Gonda Perez and the keynote presented by Robert Prince on the national benchmark tests and admissions policy of Health students.
Other presentations included research on disciplinary sub-minima in an integrated disciplinary PBL curriculum (Dr C Slater), curricular gaps (V Mitchell), the use of short case-studies to overcome first language differences (Dr V Perrot), challenges in assessment and assessor training (Dr P Wicomb & L Pienaar) and online assessment pitfalls (F van Breda & GE Doyle).
The first prize was awarded to research done on native beliefs' (misconceptions) of first year FHS students in anatomy and physiology by Dr E Badenhorst et al.
The health education research day also hosted sessions where students had an opportunity to present their research. There presentations were of high quality and will help the students in building confidence and experience by presenting to an academic audience. Expansion of the student sessions could encourage health research and learning by students, especially on the postgraduate level, across faculty disciplines.We each enjoy what we do for different reasons. When it comes to his love of Endodontics, Dean Hauseman especially likes the intensity that comes from focusing on one particular tooth.
“It’s a technically demanding procedure,” Dean says. "You have to muster a continuous, focused patience. You have to think both about what you are doing and what your patient is experiencing. But when it’s over, it’s over. The reward for me is that I get to see immediate results."
The obvious gusto with which Dean goes about his professional life permeates his life away from the office as well.
But the change in the sound of his voice tells you that he’s talking about what’s most important to him when he talks about his two kids, his daughter Yone and son Anthony - they are everything to him. He’s a highly educated professional, but it’s these more down to earth things that put you in good hands when he’s working on your tooth.
<filename>src/integrator_base.py
import utils
from abc import ABC, abstractmethod


class IntegratorBase(ABC):
    """abstract class, contains the force calculation
    that is used by all integrators

    :param dt: time step for the simulation
    :type dt: float
    :param G: gravitational constant to use, defaults to 1
    :type G: float, optional
    """

    def __init__(self, dt, G=1):
        """Constructor"""

        self.dt = dt

        self.G = G

    @abstractmethod
    def advance(self, df_clust):
        """Advance by a step

        Has to return the same value across all implemetations as it's used in Simulation
        
        :param df_clust: cluster data - position, velocity, and mass
        :type df_clust: pyspark.sql.DataFrame, with schema schemas.clust
        :returns: the new positions and velocities of the particles of the cluster, and time passed
        :rtype: tuple (pyspark.sql.DataFrame, with schema schemas.clust, float)
        """
        pass

    def calc_F(self, df_clust):
        """Calculate the force per unit mass acting on every particle::

                     N    m_j*(r_i - r_j)
            F = -G * Σ   -----------------
                    i!=j   |r_i - r_j|^3

        r - position
        m - mass
        G - Gravitational Force Constant

        :param df_clust: cluster data - position, velocity, and mass
        :type df_clust: pyspark.sql.DataFrame, with schema schemas.clust
        :returns: force per unit of mass
        :rtype: pyspark.sql.DataFrame, with schema schemas.F_id
        """

        df_F_cartesian = self.calc_F_cartesian(df_clust)

        df_F = utils.df_agg_sum(df_F_cartesian, "id", "Fx", "Fy", "Fz")
        df_F = df_F.selectExpr("id",
                               f"`Fx` * {-self.G} as Fx",
                               f"`Fy` * {-self.G} as Fy",
                               f"`Fz` * {-self.G} as Fz")

        return df_F

    def calc_F_cartesian(self, df_clust):
        """The pairwise calculations to be used for calculating F
        can be used to check which particle(s) contribute the most
        to the effective force acting on a single one

        :param df_clust: cluster data - position, velocity, and mass
        :type df_clust: pyspark.sql.DataFrame, with schema schemas.clust
        :returns: the forces acting between every two particles
        :rtype: pyspark.sql.DataFrame, with schema schemas.F_cartesian
        """
        df_clust_cartesian = utils.df_x_cartesian(
            df_clust, ffilter="id!= id_other")

        df_F_cartesian = df_clust_cartesian.selectExpr("id", "id_other", "m_other",
                                                       "`x` - `x_other` as `diff(x)`",
                                                       "`y` - `y_other` as `diff(y)`",
                                                       "`z` - `z_other` as `diff(z)`"
                                                       )
        df_F_cartesian = df_F_cartesian.selectExpr("id", "id_other",
                                                   "`diff(x)` * `m_other` as `num(x)`",
                                                   "`diff(y)` * `m_other` as `num(y)`",
                                                   "`diff(z)` * `m_other` as `num(z)`",
                                                   "sqrt(`diff(x)` * `diff(x)` + `diff(y)`"
                                                   "* `diff(y)` + `diff(z)` * `diff(z)`) as `denom`",
                                                   )
        df_F_cartesian = df_F_cartesian.selectExpr("id", "id_other",
                        