Chemistry is the scientific study of the properties and behavior of matter. It is a natural science that covers the elements that make up matter to the compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances.
Economic reliance is more profound because numerous African nations have borrowed heavily to
finance infrastructure. Chinese “Angola Model” by which exports of raw materials is
compensated by loans financing investment in infrastructure…
This work aims to study the influence of the socio-educational environment on student performance. It seeks to identify the scope of the relationship between variables or dimensions of school climate and academic performance. From 227 students and 36 public and private high school educators and colleges from the city of Agboville, we assessed their perception with the multidimensional assessment scale of student well-being in schools by Guimard et al., (2014). Multivariate regression analysis and cross-tabulations of variables have elucidated the interactions between a person’s behaviors, individual characteristics, and the environment in which they evolve. The data collected showed that school performance depends on the feeling of security, the learning conditions, the state of the teacher- student relationship, the overall satisfaction of students and their well-being in the school environment. This study proves that the best academic results of learners are intimately linked to the establishment of a quality socio- educational environment.
The water masses a term being used in oceanographic literature has been borrowed from meteorology. The water masses of specific characteristics are formed in different regions of the oceans by the processes occurring at the surface of the oceans, and ocean-atmosphere interactions at specific locations and sink from the surface to subsurface depths. They move from the region of formation and spread out to different oceans, and deep mixing eventually pulls them up through the thermocline over large areas of the ocean. It is this upward mixing that drives the deep circulation. The water mass distribution is controlled by density gradients. The two key parameters governing these differences are temperature and salinity and are routinely used to characterize it. The salinity maximum and minimum are used in a temperature – salinity (T – S) graph to distinguish a water mass in a certain area of the ocean. This method of water mass identification was introduced first time by Helland and Hansen (1916). A salinity maximum or minimum is defined as that point on a T-S curve 2 which has a salinity greater than or less than the value obtained by the mixing of the water above and below it on the curve (Stewart, 2003).
The complement system is formed form a group of sera of plasma proteins found in fresh vertebrate sera. The number of these components are ranging between 30-40 components with their own receptors. Such components appeared in vertebrate at electrophoro-grames in the arcs of alpha1 , alpha2 , beta and gamma globulins. Through , components differs from immunological characteristics. Components protein are heat labile at 56c for half an hour. Complement can be activated in sequential manner of their own component with marked subunit assembly & functional units help in phagocytosis and cell lysis components system has fluid and membrane phases and a activated in three steps initiators, amplification and membrane attack. The activation is established in three pathways ; the classical , the properidin and the lectin pathways. Properidin is found in natural immunity , classical and lectin in the adaptive immunity .
Our present knowledge of physical phenomena distinguishes four type of fundamental forces between the physical bodies: gravitational, electromagnetic weak and strong. The gravitational and the electromagnetic forces vary in strength as the inverse square of the distance and so able to influence the state of an object even at very large distances. Gravitational is important for the existence of stars, galaxes, and planetary systems as well as for our daily life, it is of no significance in subatomic physics, being far too weak to noticeably the interaction between elementary particles. Geomagnetism is the force that acts between electrically charged particles (atoms, molecules, condensed matter). When nuclear physics developed, two new short – ranged forces joined the ranks. It is well – known that the origin of the weak interaction is associated with nuclear decay. After the discovery of the neutron in 1932 by Chadwick, there was no longer doubt that the building block of nuclei are proton and neutron (collectively called nucleons). The discovery of the neutron may be viewed as the birth of the strong nuclear interaction: it indicated that the nuclei consists of protons and neutrons and hence the presence of a force that holds them together, strong enough to counteract the electromagnetic repulsion. In 1935 Yukawa have tried to develop a theory of nuclear forces. The most important feature Yukawa’s forces is that they have a small range ( 1015 m). The central dogma of atomic physics after Yukawa’s paper that proton – electron attraction could be explained in terms of classical electrostatic theory, while the strong force effects were essentially new and inexplicable (see, however below). So, far the best theoretical guess is the Yukawa potential, but it is a static potential not dependent on velocities of the nucleons. A static force is not a complete one because it can not explain the propagation of the nuclear interaction. Moreover, phenomenological Yukawa potential can not be directly verified experimentally. We should note that nowadays in text books and elsewhere the separation of electromagnetic and strong interaction tacitly assumed. It is very strange up to present time we do not even know the strong force very well. And what is more we have some contradiction taking into account that the forces between quarks must be long – range, because the gluons have zero mass. But the force between colorless hadrons is short – range, when the distance between hadrons is more than nuclear size. We can see that the border of the nuclear size transforms long – range interaction in the short – range one. It is very old question which up to present time has not any theoretical explanation
Interaction is a mutual action that cannot be separated from the characteristics of the objects participating in the process. Interaction is a process that is characterized by a simultaneous mutual change in the characteristics of interacting material objects (in our case, atoms). These material objects (atoms) act on each other with different intensity, obeying certain laws, and reproduce new structures with high accuracy. Chemical bonding is a consequence of interatomic interactions. Interatomic interactions are accompanied by thermal effects and changes in the volumes of interacting objects. Reproductive structures indicate the existence of constitutional characteristics of interacting objects. One of these characteristics is the weight concentrated in nucleons, and the second is the volume formed by the electron clouds around the nucleons. During chemical interactions, the mass concentrated in nucleons remains unchanged, and the resulting volume changes, decreasing (most often) or increasing. By the relative change in volume, as well as by thermal effects, one can judge the intensity of the interaction. Changes in the structure without changing the chemical composition occurs due to changes in the vibrations of structural units and the dissipation of energy contained in the original system into the environment [1]. With an increase in temperature (an increase in energy content), the structures dissipate. With a decrease in temperature (decrease in energy content), energy dissipation occurs. Having a crystalline system with large crystals of only one phase, without changing the chemical composition, methods of pressure, forging, laser treatment can bring the system into a state with crushed and even amorphous parts [2]. The result is a system with a high stored energy content and a dissipated structure. The fundamental characteristic of a simple substance is the molar volume, which is the ratio of the molar mass of a substance (M g/mole) to its density (d g/cm3 ) Vm=M/d (cm3 /mole) [3]. Even Lothar Meyer [4] presented a graphical dependence of atomic volumes on the mass of an atom, which was successfully illustrated by the periodic law of D.I. Mendeleev. Density is a complex characteristic, representing the ratio of one unchanged constitutional quantity (mass) to another constitutional quantity (volume), which changes depending on the environment by other atoms [5, 6].
Cholera is a diarrheal syndrome of an infectious epidemic or pandemic nature. This syndrome expressed several epidemic and pandemic spread all over the world during sixties, seventies eighties and nineties of the twentieth century. Cholera caused by V. cholerae serotypes ,the known OI and non-OI serotypes.It seems to be that there were other entero-pathogen like entero-toxigenic Escherichia coli may express such diarrheal syndrome but with neither evident epidemicity nor form water diarrhea .The syndrome has been described as water and food born.It is considered as an enterotoxin induced in which the enterotoxin induce adenyl cyclase. The denyl cyclase in turn induced fluid accumulation in the affected patients gut leading to rice water diarrhea.Infected patient need ;fluid re-susstation ,quarantine and Tetracyclin R derivative therapy.Prove of V.cholerae pathogenicity in mice or other small animal mammals was through the application of the ligated ileal loop technic. The infection induced immunity may be antitoxic, anti-bacterial and vibriocidal antibody responses. Several vaccine makes are known to date that can be of use in facing the epidemic episodes in different world countries[ Holmgren 2021,Momba and Azab EL-Liethy 2017,Sakazaki et al 1970].