Conditional recovery of time-reversal symmetry in many nucleus systems

Propagation of non-topological soliton in many-nucleus systems is studied based on time-dependent density functional calculations with focusing on mass and energy dependence. The dispersive property and the nonlinearity of the system, which are inherently included in the nuclear density functional, are essential factors to form a non-topological soliton. On the other hand the soliton propagation is prevented by the charge equilibration dynamics, and the competition possibly appears. In this article, based on the energy-dependence of the two competitive factors, the concept of conditional recovery of time-reversal symmetry is proposed in many nucleus systems. It clarifies a possibility of preserving nuclear medium inside natural or artificial nuclear reactors, under a suitable temperature. From an astrophysical point of view, the existence of the low-temperature solitonic core of compact stars is suggested.Comment: Submitte

Working with student expectations of tutor support in distance education: testing an expectations‐led quality assurance model

Action research studies in the United Kingdom with Open University students have shown that students come to distance education courses with variable expectations of the levels of service and support they will receive from their tutors. It has been further suggested that a specific expectations-led quality assurance process that enables the sharing of these expectations before a course starts could be of mutual benefit to the student and the tutor, as well as generally improving the overall quality of tutor support provided by the distance learning organisation. This process, it is argued, would be appreciated by the students, have beneficial effects on student satisfaction with tutor support, reducing student drop-out and increasing course completion rates. Could such a process that asks tutors to collect student expectations before a course begins be instituted effectively into a distance learning organisation and how would students and tutors respond to it? This paper reports on a large-scale project carried out by Oscail (the Irish National Distance Education Centre) aimed at developing and testing how students and tutors valued being involved in just such an Open and Distance Learning expectations-led quality assurance process. In the study reported here, all 96 tutors on an Oscail B.A. distance learning programme were asked two weeks before their course began to circulate the student expectations questionnaire to the 950 students on their tutorial lists. Tutors were asked to collect the questionnaires, reflect on the expectations of the students and consider how their tutorial practice and student support might change as a result of the exercise. Tutor and student views on the effectiveness of the exercise were also gathered through questionnaires and focus group meetings. The findings suggested that the majority of students and tutors involved in the study did see the value of the process and that it did help tutors (especially newly appointed ones) consider and respond to the type of support students hoped to receive. The practice of issuing student expectation questionnaires has now been embedded in Oscail introductory courses

Tax Policies and Residential Mobility

Governmental tax policies have direct consequences for public spending and the distribution of wealth among a country’s population. But unintended consequences may also occur as a result of the design of those policies. We illustrate the potential impact of such unintended consequences by analyzing differences in home ownership mobility in California, Illinois, and Massachusetts that appear to result from the distinct differences in the design of real estate tax polices across these states. California’s Proposition 13, which became law in 1978, limits the increase in real estate taxes to a maximum of 2% in any given year regardless of home value appreciation. With home value appreciation, Proposition 13 creates sizeable disincentives to move. The evidence from an analysis of single family home sales records in California, Illinois, and Massachusetts indicates that California’s homeowners are significantly less mobile than their counterparts in Illinois and Massachusetts. The lower mobility was clearly not intended by the passage of Proposition 13, though its impact on society is potentially very significant. We recommend that countries in the process of developing tax systems for residential real estate ownership (such as China, the countries of the former USSR, and many countries in Africa) take account of such originally unintended consequences.California, Real Estate Tax, Residential Mobility, Unintended effect

Surface phosphatase activity of peltigera and cladonia lichens

This study examines the effects of environmental factors on the surface phosphatase activities of the lichens Peltigera canina (L.) Willd., P. praetextata (Flōrke. ex Sommerf) Vain, and Cladonia arbuscula (Wallr.) Rabenh. Four plants of each species were collected in the U. K. from low (Middleton Common, Windy Nook) and high (Nenthead) Zn environments. The mean tissue (soil) Zn concentrations in P. canina, P. praetextata and C. arbuscula (high Zn) were 4.3 (18.9), 5.4 (25.4) and 4.1 (8.3) times higher respectively than the same species (low Zn).Phosphomonoesterase (PMEase) activity was measurable at all pH values in the range 3.0 - (10.3) 11.0 with 250 µM p-nitrophenyl phosphate (pNPP) and 250 µM 4-methylumbelliferyl phosphate (4-MUP) Both pNPP and 4-MUP showed maximum PMEase at pH: 10.3 in P. canina (low Zn), P. praetextata (low and high Zn); 6.0 in P. canina (high Zn), C. arbuscula (low Zn); 6.0-7.0 in C. arbuscula (high Zn). Maximum PMEase in P. canina and P. praetextata (high Zn) exceeded maximum PMEase in the same species (low Zn), while the converse was true for C. arbuscula. Fluorometric determination of PMEase with 4-MUP yielded lower maximum rates of activity in all species from low and high Zn environments than spectrophotometric methods (pNPP).PMEase activity in all species from low and high Zn environments exceeded phosphodiesterase (PDEase) activity between 1.5 and 5.1 times. P. canina and P. praetextata displayed a greater tolerance to Zn than C. arbuscula, with inhibitory effects on PMEase activity noticeable at 1 mM in P. canina, and P. praetextata (high Zn) and 10 µM Zn in all other plants. Storage for six weeks, rhizinal cellular damage and light all resulted in an increase in PMEase activity with 250 µM pNPP in P. canina (high Zn) of less than 4 %. The lower layer (rhizines and veins) of P. canina was shown to have greater PMEase activity at all pH values, with 1 µM 4-MUP, 250 µM 4-MUP and 250 µM pNPP. Staining techniques undertaken on P. canina (high Zn) suggest that phosphatase activity is probably due to the fungus, especially the rhizines and veins, and not the cyanobacterium or contaminant bacteria. PMEase and PDEase were associated with the cell wall, cytoplasm and most noticeably at hyphal junctions. All plants displayed maximum PMEase activities at pH values which did not correspond with any of the presumed soil pH values

Using Satellites to Probe Extrasolar Planet Formation

Planetary satellites are an integral part of the heirarchy of planetary systems. Here we make two predictions concerning their formation. First, primordial satellites, which have an array of distinguishing characteristics, form only around giant planets. If true, the size and duration of a planetary system's protostellar nebula, as well as the location of its snow line, can be constrained by knowing which of its planets possess primordial satellites and which do not. Second, all satellites around terrestrial planets form by impacts. If true, this greatly enhances the constraints that can be placed on the history of terrestrial planets by their satellites' compositions, sizes, and dynamics

Adolescent reproductive health and awareness of HIV among rural high school students, North Western Ethiopia.

Ethiopia is faced with an increasing problem from HIV infection, and the vulnerability of adolescents is a key concern. There is little information on the knowledge, attitudes and practices of this age group with respect to HIV, sexually transmitted diseases and preventive measures. We conducted a cross-sectional study among 260 students from two rural high schools in North Western Ethiopia. We found that although the general awareness of HIV was high, correct knowledge of the virus and its modes of transmission was shown in only 44% of adolescent boys and 41% of adolescent girls. Knowledge of HIV and condoms was lower among students whose parents were farmers, significant so among girls (p=0.02). Use of condoms among sexually active single male students (49%) was insufficient but was higher than among adolescents in many other African settings. Knowledge of STDs was generally low: 82% of adolescent males and 37% of adolescent females had some awareness of STDs. Almost 20% of sexually active males in the study had previously experienced an STD, almost all of whom had visited a commercial sex worker. Targeted interventions are warranted among adolescents and sex workers in Ethiopia complemented by STD treatment services

Faint galaxy photometry and cosmology

Deep galaxy catalogues have been constructed from automatic measurements of photographic plates by the COSMOS machine at the Royal Observatory Edinburgh. The plates were taken by the 1.2m UK Schmidt telescope (UKST) and 4m Anglo-Australian telescope (AAT), in both blue and red passbands. The UKST plates cover an area of sky of~170 square degrees, some four times larger than any previous study to these depths (B-21, R~20mag).By comparing the UKST and AAT galaxy number-magnitude counts and colour distributions with those predicted using computer models, evidence for luminosity evolution has been obtained. The red passband counts require less luminosity evolution than in the blue passband and at the faintest magnitudes reached here (R'-22mag) the cosmological parameter, q(_o), has as large an effect. The red count models are well enough determined to reject world models with q(_o)> 1. In order to further separate the effects of luminosity evolution and q^, the possibility of using a well determined Hubble diagram or faint "galaxy redshift surveys is considered. The galaxy two-point angular correlation function, w(ɵ), has been estimated from the UKST catalogues and shows evidence of a feature at large angular scales, corresponding to a spatial separation of ~3h Mpc (H(_o) = l00h kms Mpc ). In a study of the correlation function scaling relation it is found that the observed clustering amplitudes at AAT depths are lower than those predicted using well determined models that assume no clustering evolution. However, sampling errors are large and more 4m data is required in order to test the reality of this result. Also discussed is the possibility of discriminating between recent theories of galaxy formation using the w(#) observations. The method of Turner and Gott has been used to automatically detect groups and clusters of galaxies in the UKST catalogues. It is found that the cluster-cluster w(f) is several times higher than the galaxy-galaxy w(4) when scaled to the same depth. The implications of this result for galaxy formation theories are discussed. By using the average magnitude, m, of a cluster as a distance estimator the redshift distribution of the clusters has been obtained. Features present in these distributions^ may correspond to the effects of superclustering on scales < l50h (^-1)Mpc. The modelled m:distance relation has been used to set constraints on the galaxy luminosity function and hence help to more tightly constrain the number count and clustering models. The orientations of galaxies within clusters and the orientations and ellipticity distributions of the clusters themselves have been used in order to obtain further constraints on the theories of galaxy formation

Relative stable categories and birationality

We propose a general method to construct new triangulated categories, relative stable categories, as additive quotients of a given one. This construction enhances results of Beligiannis, particularly in the tensor-triangular setting. We prove a birationality result showing that the original category and its relative stable quotient are equivalent on some open piece of their spectrum

A Consequence of Recovery from Defeat in a Territorial Animal

Population density has profound influences on the physiology and behaviour of many animal species. Social isolation is generally reported to lead to increased aggressiveness, while grouping lowers it. We evaluated the effects of varying degrees of isolation and grouping on aggression in a territorial insect, the Mediterranean field cricket, Gryllus bimaculatus. Substantiating early observations, we show that dyadic contests between weight-matched, adult male crickets taken from groups rarely escalate beyond threat displays, whereas interactions between pairs of previously isolated crickets typically escalate to physical fights lasting several seconds. No significant differences were found between 1, 2 and 6-day isolates, or between individuals grouped for a few hours or lifelong. Unexpectedly, crickets grouped in immediate proximity within individual mesh cages that precluded fighting while permitting visual, olfactory and mechanical, antennal contact, were as aggressive as free isolates. This suggests that reduced aggression of grouped animals may be an acquired result of fighting. Supporting this notion, isolated crickets initially engage in vigorous fights when first grouped, but fighting intensity and duration rapidly decline to the level of life-long grouped crickets within only 10 min. Furthermore, grouped crickets become as aggressive as life-long isolates after only 3 hours of isolation, and on the same time course required for crickets to regain their aggressiveness after social defeat. We conclude that the reduced aggressiveness of grouped crickets is a manifestation of the loser effect resulting from social subjugation, while isolation allows recovery to a state of heightened aggressiveness, which in crickets can be considered as the default condition. Given the widespread occurrence of the loser effect in the Animal Kingdom, many effects generally attributed to social isolation are likely to be a consequence of recovery from social subjugation