Involvements of Hyperhomocysteinemia in Neurological Disorders

Homocysteine (HCY), a physiological amino acid formed when proteins break down, leads to a pathological condition called hyperhomocysteinemia (HHCY), when it is over a definite limit. It is well known that an increase in HCY levels in blood, can contribute to arterial damage and several cardiovascular disease, but the knowledge about the relationship between HCY and brain disorders is very poor. Recent studies demonstrated that an alteration in HCY metabolism or a deficiency in folate or vitamin B12 can cause altered methylation and/or redox potentials, that leads to a modification on calcium influx in cells, or into an accumulation in amyloid and/or tau protein involving a cascade of events that culminate in apoptosis, and, in the worst conditions, neuronal death. The present review will thus summarize how much is known about the possible role of HHCY in neurodegenerative disease.

Methodology of teaching the techniques of playing volleyball among 11-12 year-old boys

In all games, connected with the ball, main attention of a player should be paid to a moving ball. This rule ignoring leads to often inaccurate ball hitting. Admittedly, players should be taught to observe the opponent. But at the same time direct observation is held to the definite limit. And during the moment of direct training and hit fulfillment main attention is paid to the ball and other environment is observed only with the help of peripheral vision. During the game young volleyball players lose many favorable moments only because they can’t choose the best ways of a hit in the combat with the opponent. During the playing technique explanation and study it is necessary to study thoroughly the basis of the technique, the sequence of the separate body parts movements, speed and their amplitude during different techniques fulfillment. These factors are the main for volleyball player’s actions effectiveness achievement. While the attacking hit fulfillment and blocking it is important to control the opponent during the technique fulfillment. That is why it is necessary to master the ability to observe the opponent’s movements all the time, till the hit on the ball, among young volleyball players.

Nova Imago Urbis: the transformation of city walls in early Renaissance as a model for the contemporary city image.

The introduction of the artillery in the middle 15th century represented a revolution not only from a strictly military perspective: at the same time that medieval defences become obsolete and were replaced with other kind of fortifications, the cities lost their crenelated walls and slim towers that until then had configured their image and expression. The forced loose of this medieval Imago Urbis and the urgency of finding a new formal expression for this new type of fortifications was quickly understood by the leading Italian Renaissance architects. From Francesco di Giorgio Martini to Baldassarre Peruzzi, from Giuliano da Sangallo to Michelangelo, all of them –aware of the importance of the problem­– worked on developing this new type of fortifications not only from the technical standpoint but also from its symbolic and formal approach. In Albertian terms, the goal was to search a new façade that would represent once again that “great house” that is the City. The contribution will refer to the importance of the contributions made by these architects in this regard and of its exemplary value in facing this problem –that of the image of the city– in our cities, the contemporary ones, increasingly more and more extensive and without a definite limit.

Rough Clustering Method Based on Particle Swarm Optimization Algorithm

As a relatively novel clustering approach, Particle Swarm Optimization (PSO) prevents k-means algorithm from falling into local optimum effectively, and has made relatively notable successes in clustering, however, using Hard C-Means algorithm when randomly obtaining initial clustering centers is required in most existing PSOs, while no definite limit existing in these samples actually. Based on this, we utilized an improved PSO; along with effective processing methods on boundary objects of Rough Set Theory, we proposed a new rough clustering algorithm based on PSO. It can adjust the upper and lower approximations weighting factors dynamically, and coordinate the proportions of upper and lower approximations in different generations as well. Finally, we compared it with several common clustering methods using Iris dataset of UCI. It turned out that the algorithm has higher accuracy and stability, along with better comprehensive performance.

Numerical Investigation of Collision-Induced Breakup of Raindrops. Part I: Methodology and Dependencies on Collision Energy and Eccentricity

Binary collisions of large raindrops moving with terminal fall velocity are numerically investigated using FS3D, a direct numerical simulation (DNS) code based on the “volume of fluid” method. The result of this process can be a permanent coalescence or a temporal coalescence followed by a breakup of the coalesced system into smaller-sized remnants of the original raindrops and a number of fragment droplets of different sizes. In total, 32 drop pairs are studied with sizes chosen to cover nearly completely the entire size parameter range relevant to breakup. This is an important extension of investigations performed in 1982 by Low and List, who studied 10 drop pairs only. Moreover, eccentricity has been introduced as an additional parameter controlling the collision outcome. Eccentricity is defined as the horizontal distance of the initial drops’ centers with values equal to approximately 0 for centric and 1 for grazing collisions. The main results include numerically calculated data of coalescence efficiencies and fragment size distributions with emphasis on eccentricity effects. It is shown that eccentricity largely determines the appearance of specific breakup modes and consequently the respective fragment size distributions. Comparisons are made with the main findings of Low and List. Coalescence efficiency values larger than those derived by Low and List show up for very small Weber numbers. Additionally, the existence of their definite limit value of collision kinetic energy necessary for coalescence could not be confirmed. The fragment size distributions are in some cases similar to those measured by Low and List but there are also major differences for other cases. The presented results are used for parameterizations of coalescence efficiencies and fragment size distributions as well as for calculations of stationary drop spectra shown in Part II of this study.

Educational Technology: Will it Spread?

A turning point in the computer revolution is at hand. During the past twenty-five years spectacular developments in electronic technology have occurred. The probable future for instructional technology is an extension of current directions in computer, video, and other areas of electronic technology. Production of media materials will be simplified by programmable personal computer cameras that record images digitally rather than on film, voice activated word processing and computer graphics. Teachers may assume a defensive posture. Their fears may be groundless as there is a definite limit to the time which learners can spend at a computer terminal. The future promises to make learning truly individual and universal.

Horizon formation by molten organic salts as a test of their fluidity

A simple but sensitive horizon test is described to determine whether the mesophases of molten organic salts exhibit any detectable elastic-plastic threshold, before they begin to flow under even very small applied shear stresses. By using this test with sodium isovalerate (mesophase range 188–280 °C) no detectable threshold is found above about 260 °C; above this temperature the melt thus behaves as completely fluid. However, between this temperature and the first melting point (188 °C) a definite limit stress appears to be required to start flow. Other properties of the mesophase also show changes around 260 °C with some analogies to fluid–glass transi­tions in other systems. Molten sodium n -butyrate, when tested in a similar way, fails to exhibit any distinctive elastic-plastic threshold. So far as can be detected by the horizon test, it remains completely fluid over the whole of its meso­phase range (252–324 °C).

Territoriality and the Influence of Females On the Spacing of Males in the Cockroach, Nauphoeta Cinerea

Abstract(I) The first aim of the study was to extend earlicr observations on the effect of density on social structure and in particular to see if all males in a group became territorial at very low density. The second aim was to determine the social organisation of females in relation to territorial males. (2) Most males were observed to become territorial at very low density but there was a definite limit to the tendacy to spread out. A few males were not territorial and the behaviour of these animals is described. (3) The females formed a group, usually but not always, on a male-occupied territory. Unreceptive, virgin females introduced into the observation tank remained inactive for the first few days. In these females activity and exploration were correlated with the onset of receptivity. Some females mated at this time and then moved on until they joined the female group. Others joined the female group immediately and mated with the territory owner if one was present. Once females had joined the group they did not leave except for brief sallies or to give birth to their young. The female group did however move en masse and sometimes moved the entire length of the tank. (4) One of the most obvious effects of the females was on the pattern of male territory holding. Competition for territory centred round the female group and several males took up residence with the females during the day. Either one of these males became a despot or a hierarchy of dominance developed. At night the top-dominant chased the others off his territory. These males, with the exception of a few very low-ranking males, then set-up territories on adjacent rest-sited and made occasional attempts to rejoin the female group. This sequence of events was repeated each day. (5) The second obvious effect of the females was on the amount of fighting. Males were alone more often than they were with females but when females were present there was more fighting. (I) The relationship between hierarchy and territory is discussed and conclusions are drawn about the function of territory and the limitations of the territorial system in Nauphoeta.

Ethnographic Life: Method for an Ex Post Facto Anthropology

Every ethnography has a beginning and an end, decided more or less arbitrarily by the anthropologist. In general, it has a simultaneously temporal and spatial beginning. Currently, spatial issues have been relaxed, but temporal issues are still a definite limit. This article reflects on the constitution of anthropological knowledge when the field has no such limits. What if any moment of our experiences can be seen a period of “ex post facto” ethnographic fieldwork? Is it possible to perform an ethnography without borders? What methods should we articulate to build knowledge without the separation between life and ethnography? Why is ethnography a life experience, when we do not often think of life as an ethnographic experience? And what happens if we think that life is indeed an ethnographic experience? This article deals with anthropological knowledge without borders and memory as a methodological resource.

Mechanical activity of rat papillary muscle

Isometric contractions of isolated rat papillary muscles driven at a constant rate have been recorded from paired muscles from hearts of rats 2–6 months of age. At 37°C and a rate of 30/min. tension reaches maximum in 30–60 minutes and then declines slowly during the succeeding 4–12 hours. The maximum tension and the rate of decline with time are related to the diameter of the muscle; however, it has not been possible to demonstrate a definite limit to diameter below which the contraction of the muscle is independent of variations in size. Most factors which increase the force of contraction do not prevent the slow decrease in tension with time. Two exceptions are low temperature (27°C) and high rate (180/min.); under either of these conditions a steady level of tension is maintained for several hours or more. The response of the isolated rat papillary muscle to various physiological alterations is consistent and reproducible if variations in size are considered.