Mating systems,philopatry and dispersal in birds and mammals

Many species of birds and mammals are faithful to their natal and breeding site or group. In most of them one sex is more philopatric than the other. In birds it is usually females which disperse more than males; in mammals it is usually males which disperse more than females. Reproductive enhancement through increased access to mates or resources and the avoidance of inbreeding are important in promoting sex differences in dispersal. It is argued that the direction of the sex bias is a consequence of the type of mating system. Philopatry will favour the evolution of cooperative traits between members of the sedentary sex. Disruptive acts will be a feature of dispersers.     

GU evaluation and management of renal transplant candidates and recipients

There are more than 200,000 end stage renal disease (ESRD) patients who are potential transplant candidates and more than 100,000 previously transplanted renal recipients with functioning allografts in the United States. Fifty-seven percent of these patients are male and forty percent are greater than 50 years of age. Diabetes is the most common cause of kidney failure. It is evident that many patients are at high risk for development of urologic problems and thus it is estimated that the average urologist will care for up to ten of these patients yearly. Thus a review of the genitourinary (GU) evaluation and management of these patients is timely.     

Issues and opportunities of stem cell therapy in autoimmune diseases

The purpose of regenerative medicine is to restore or enhance the normal function of human cells, tissues, and organs. From a clinical point of view, the use of stem cells is more advantageous than differentiated cells because they can be collected more easily and in larger quantities, their proliferation capacity is more pronounced, they are more resistant in cell culture, their aging is delayed, they are able to form a number of cell lines, and they are able to promote vascularization of tissue carriers. The therapeutic use of stem cells for disease modification, immunomodulation, or regenerative purposes are undoubtedly encouraging, but most studies are still in their early stages, and the clinical results reported are not clear with regard to therapeutic efficacy and potential side effects. Uniform regulation of the clinical application of stem cells is also indispensable for this highly customizable, minimally invasive, individualized therapeutic method to become a successful and safe treatment alternative in many different autoimmune and autoinflammatory disorders.     

Motor and sensory reinnervation of fast and slow mammalian muscles

Summary 1. The formation of endplates outside the original endplate region of a muscle fibre was studied in slow and fast rat muscles. It was found that such new endplates are readily formed on the soleus muscle, whereas hardly at all in the fast extensor digitorum longus. Most new endplates appear to be morphologically normal within 2 months after nerve implantation.2. The time course of recovery of slow and fast cat muscles was followed after crushing the sciatic nerve. It was found that the slow soleus muscle recovers more rapidly than the fast flexor hallucis longus muscle.3. The endplates of reinnervated cat muscles are more complicated than those of the control muscles, but have nevertheless fewer nerve terminals per endplate. Reinnervated muscles are more sensitive to curare and it is suggested that this is due to a decrease in transmitter release, for it was found that less acetylcholine is released from reinnervated rat hemidiaphragms than from control ones.4. Motor and sensory reinnervation of spindles and tendon organs was studied. At the time when motor reinnervation is almost completed the sensory endings from spindles and tendon organs are highly abnormal. Thus sensory reinnervation proceeds much more slowly than motor.     

Size and scaling in the mandible of living and extinct apes

The purpose of this study is to fill a gap in our knowledge of dietary and allometric determinants of masticatory function and mandibular morphology in major catarrhine clades. To extend the implications of previous work on variation in mandibular form and function in other primates, a scaling analysis was performed on 20 extinct and 7 living non-cercopithecoid catarrhines or 'dental apes'. Results of allometric comparisons indicate that for a given jaw length, larger apes exhibit significantly more robust corpora and symphyses than smaller forms. This appears linked to size-related increases in dietary toughness and/or hardness, which in turn causes elevated mandibular loads and/or greater repetitive loading during unilateral mastication. Larger-bodied dental apes also display more curved symphyses, which also explains the positive allometry of symphysis width and height. In apes, proconsulids often evince more robust jaws while all hylobatids, Pan and Dryopithecus laietanus possess more gracile cross sections. In propliopithecids, Aegyptopithecus is always more robust than Propliopithecus. In proconsulids, Rangwapithecus and Micropithecus commonly exhibit more robust jaws whereas Dendropithecus and especially Simiolus are more gracile. Most of the larger taxa are folivorous and/or hard-object frugivorous pongids with relatively larger dentaries. Though apes have relatively wider corpora than cercopithecines due to greater axial twisting of the corpora during chewing, they are otherwise alike in robusticity levels. Smaller apes are similar to cercopithecines in evincing a relatively high degree of symphyseal curvature, while larger taxa are like colobines in having less curvature. Larger pongids resemble or even exceed colobine jaw proportions and thus appear to converge on colobines in terms of the mechanical properties of their diets.     

Ecology and management of invasive Pinaceae around the world: progress and challenges

Many species in the family Pinaceae are invaders. These species are relatively easy to control because of some of their intrinsic characteristics and because they are highly visible and easy to eliminate. Many Pinaceae species have been well studied because of their use in forestry and their invasive behavior in many countries. The impacts of invasive Pinaceae are not only ecological, but also economic and social. We review the ecology and management of Pinaceae invasions and explore how restoration of invaded areas should be addressed. There are many ways to prevent invasions and to deal with them. Planting less invasive species, better site selection, and invasion monitoring are used successfully in different parts of the world to prevent invasion. Mechanical and chemical methods are used effectively to control Pinaceae invasions. Control is more effective at the early stages of invasion. Old invasions are more problematic as their elimination is more expensive, and the restoration of native vegetation is challenging. In some areas, native vegetation cannot thrive after Pinaceae have been removed, and weeds colonize cleared areas. More attention is needed to prevent the initiation and spread of invasions by focusing control interventions at early stages of invasion. Finding new ways of dealing sustainably with conflicts of interest between foresters and conservationists is crucial. Non-native Pinaceae are important parts of the economies and landscapes in several countries and they will continue to play such a role in the future. Despite the numerous challenges facing Pinaceae invasion management, several approaches can be successful at controlling them. Proper application of current techniques and development of more efficient ones is needed if the goal of maximizing benefits and minimizing negative impacts is to be achieved.     

Connection between classroom abuse and manifest aggressiveness, anxiety and altruism

The objective of this paper is to find out if the students exposed to abuse differ in their level of anxiety, aggressiveness, and altruism from other students, and to test if the pattern of these differences differs depending on whether the abuse they suffer is emotional or physical. The research was carried out on a sample of 127 senior elementary school students. The data was gathered at the end of the 2003/04 school year, and obtained through the respondents' self-statements in questionnaires about childhood abuse and by the scales of manifest aggressiveness, anxiety and altruism. The frequency analysis has shown that various forms of emotional abuse are more common in schools than physical abuse, and that they are reaching disturbing proportions. For example, more than half of the participants in the study reported facing intimidation and threats in school, and over a third of them have been yelled at. Although less commonplace, physical abuse in school can by no means be ignored. Those students who suffer from frequent physical abuse are more dissatisfied with school (r=0.174, p<0.05), display more aggressiveness (r=0.441, p<0.001), and are more often boys (r=0.324, p<0.01). Those students who are frequently emotionally abused are more anxious (r=0.281, p<0.01), dissatisfied with school (r=0.237, p<0.01), and display more manifest aggressiveness (r=398, p<0.01). The discriminant analysis has shown that the bullied students can be differentiated from their non-abused schoolmates as they are manifestly more anxious and aggressive, regardless of whether they suffer physical or emotional abuse. Instances of different forms of emotional and physical classroom abuse have increased alarmingly. Such traumatic experiences affect children's health and functioning in school, as well as in their private lives. The interdisciplinary studies of this phenomenon and the education of all those who work with young people emerge as the top priority in the prevention of this kind of abuse.     

Evolution and the Cumulative Nature of Science

One of the characteristics of science is its cumulative nature. As more discoveries are made and more is learned, we progressively come to a more and more complete understanding of the physical universe. Evolutionary biology serves as an excellent example of this progressive trend in knowledge, since we now understand significantly more about the mechanisms and details of the evolutionary process than we did in decades past. It is important to comprehend these progressive changes and communicate them effectively to students of evolutionary biology.     

旧石器时代早中期刻划遗存的发现与研究

刻划遗存是史前人类有意刻划并保留下来的重要考古资料,对于探索和揭示史前时期古人类认知能力和思维表现形式等方面具有重要作用。目前,刻划遗存的发现与研究工作主要集中在欧洲、非洲南部和西亚地区,中国发现的刻划遗存较少。本文重点介绍当前国内外刻划遗存的发现和研究情况,在此基础上,对刻划遗存的鉴别和分析方法进行总结,并尝试探讨不同时空刻划遗存的差异。本文认为古人类刻划行为出现于旧石器时代早期,在旧石器时代中期呈现出地域发展不平衡的特点。     

Intelligence and homosexuality

The origin of preferences and values is an unresolved theoretical problem in behavioural sciences. The Savanna-IQ Interaction Hypothesis, derived from the Savanna Principle and a theory of the evolution of general intelligence, suggests that more intelligent individuals are more likely to acquire and espouse evolutionarily novel preferences and values than less intelligent individuals, but general intelligence has no effect on the acquisition and espousal of evolutionarily familiar preferences and values. Ethnographies of traditional societies suggest that exclusively homosexual behaviour was probably rare in the ancestral environment, so the Hypothesis would predict that more intelligent individuals are more likely to identify themselves as homosexual and engage in homosexual behaviour. Analyses of three large, nationally representative samples (two of which are prospectively longitudinal) from two different nations confirm the prediction.     

Cloning technologies for protein expression and purification

Detailed knowledge of the biochemistry and structure of individual proteins is fundamental to biomedical research. To further our understanding, however, proteins need to be purified in sufficient quantities, usually from recombinant sources. Although the sequences of genomes are now produced in automated factories purified proteins are not, because their behavior is much more variable. The construction of plasmids and viruses to overexpress proteins for their purification is often tedious. Alternatives to traditional methods that are faster, easier and more flexible are needed and are becoming available.     

Introns and reading frames: correlation between splicing sites and their codon positions

Computer analyses of the entire GenBank database were conducted to examine correlation between splicing sites and codon positions in reading frames. Intron insertion patterns (i.e., splicing site locations with respect to codon positions) have been analyzed for all of the 74 codons of all the eukaryote taxonomic groups: primates, rodents mammals, vertebrates, invertebrates, and plants. We found that reading frames are interrupted by an intron at a codon boundary (as opposed to the middle of a codon) significantly more often than expected. This observation is consistent with the exon shuffling hypothesis, because exons that end at codon boundaries can be concatenated without causing a frame shift and thus are evolutionarily advantageous. On the other hand, when introns interrupt at the middles of codons, they exist in between the first and second bases much more frequently than between the second and third bases, despite the fact that boundaries between the first and second bases of codons are generally far more important than those between the second and third bases. The reason for this is not clear and yet to be explained. We also show that the length of an exon is a multiple of 3 more frequently than expected. Furthermore, the total length of two consecutive exons is also more frequently a multiple of 3. All the observations above are consistent with results recently published by Long, Rosenberg, and Gilbert (1995).      

Protection by beta-carotene and related compounds against oxygen-mediated cytotoxicity and genotoxicity: implications for carcinogenesis and anticarcinogenesis.

beta-Carotene protects against photooxidative dermatitis in porphyric humans and mice by quenching of photoactivated species. Other actions of beta-carotene in vivo are explained on the basis of its ability to scavenge free radicals in vitro. For example, in guinea pigs treated with CCl4, beta-carotene decreases pentane and ethane production. Epidemiological studies link low serum beta-carotene levels to elevated risk of lung and other cancers, and in intervention trials, beta-carotene diminishes preneoplastic lesions. However, the dose/response relationships are not well established, and antineoplastic mechanisms await clarification. Given a radical quenching mechanism, beta-carotene should block tumor promotion, but more typically the site of action is progression and an even later role in invasion has not been ruled out. Some antineoplastic actions of carotenoids (such as increased rejection of fibrosarcomas in mice) are attributed to immunoenhancement; others may reflect conversion to retinoids and subsequent gene regulation. Carotenoids other than beta-carotene may act at an earlier stage of carcinogenesis or be more effective as anticarcinogens at certain target sites. As scavengers of hydroxyl radicals, canthaxanthin and astaxanthin are more effective than beta-carotene. Canthaxanthin is sometimes more effective than beta-carotene in chemoprevention, but it is sometimes completely ineffective. Lycopene quenches singlet oxygen more than twice as effectively as beta-carotene. However, the antineoplastic actions of lycopene or astaxanthin remain untested. Explorations of the interactions of carotenoids with other nutrients are just beginning. Dietary fat increases absorption of carotene but decreases antineoplastic effectiveness. Research is hampered by technical problems, including the unavailability of rigorous controls, the instability of carotenoids, and the heterogeneous phase structure induced by hydrophobic compounds in aqueous media. Areas of current controversy and promising approaches for future research are identified.     

Sexual selection and the evolution of genital shape and complexity in water striders

Animal genitalia show two striking but incompletely understood evolutionary trends: a great evolutionary divergence in the shape of genitalic structures, and characteristic structural complexity. Both features are thought to result from sexual selection, but explicit comparative tests are hampered by the fact that it is difficult to quantify both morphological complexity and divergence in shape. We undertake a comparative study of multiple nongenitalic and male genital traits in a clade of 15 water strider species to quantify complexity and shape divergence. We show that genital structures are more complex and their shape more divergent among species than nongenital traits. Further, intromittent genital traits are more complex and have evolved more divergently than nonintromittent genital traits. More importantly, shape and complexity of nonintromittent genital traits show correlated evolution with indices of premating sexual selection and intromittent genital traits with postmating sexual selection, suggesting that the evolution of different components of genital morphology are shaped independently by distinct forms of sexual selection. Our quantitative results provide direct comparative support for the hypothesis that sexual selection is associated with morphological complexity in genitalic traits and highlight the importance of quantifying morphological shape and complexity, rather than size in studies of genital evolution.     

A study of three IACUCs and their views of scientific merit and alternatives

Two ethical issues facing Institutional Animal Care and Use Committees [IACUCs] today are assessing scientific merit and the use of alternatives in research proposals. This study evaluated 3 IACUCs using a 19-question survey, with a 77.8% response rate. Although 76% of members answered that scientific merit should be more dili-gently assessed if more than slight pain is caused, 14% believed that assessing scien-tific merit is not the role of the IACUC. Nearly 86% agreed that the search for alterna-tives should be more diligent for protocols that incur more than slight pain to the animals involved. Some members believed that alternatives were not actively enough sought after, while others believed no viable alternatives existed. Additional guide-lines are needed to clarify these issues.     

Glycerophospholipid metabolism in neuronal and glial cell-enriched fractions

The metabolism of phospholipids in separated glial and neuronal cells has been reviewed in this paper. Lipids are more abundant in glia; on the other hand, in vivo experiments performed with labeled precursors have indicated that lipid turnover is faster in neurons (with the possible exception of oligodendroglia). Biosynthetic and catabolic enzymes of lipid metabolism have been studied in separated cells (mainly in neurons and astroglia) and have been shown to be almost always more active in neurons. Also base exchange is probably more active in these cells. Therefore the results of in vitro and in vivo experiments indicate that neurons are more active than astroglia in metabolizing glycerophospholipids.     

The physician,the parent and the retarded child

The problem of the retarded child and his parents is one confronting practicing physicians more and more frequently. Current estimates indicate that state hospital facilities for retarded persons in California are short nearly 6,000 beds. There are long waiting lists for available facilities. Many families are in desperate need of help. To advise a family to send their child to a State hospital is not a real solution nor one possible in the great majority of instances. The responsibility of the physician goes beyond this. Parents' groups have developed in the last few years and are making a real contribution to a resolution of the problem. Local community resources have increased and will further increase. A more accurate clinical understanding of the retarded child has been formed and his treatment needs more clearly defined. Physicians, parents, community and State agencies must work together to effect a coordinated program.     

Cryptanalysis and Improvement of a Biometric-Based Multi-Server Authentication and Key Agreement Scheme

With the security requirements of networks, biometrics authenticated schemes which are applied in the multi-server environment come to be more crucial and widely deployed. In this paper, we propose a novel biometric-based multi-server authentication and key agreement scheme which is based on the cryptanalysis of Mishra et al.’s scheme. The informal and formal security analysis of our scheme are given, which demonstrate that our scheme satisfies the desirable security requirements. The presented scheme provides a variety of significant functionalities, in which some features are not considered in the most of existing authentication schemes, such as, user revocation or re-registration and biometric information protection. Compared with several related schemes, our scheme has more secure properties and lower computation cost. It is obviously more appropriate for practical applications in the remote distributed networks.     

Endogenous oestrogens and breast cancer risk in premenopausal and postmenopausal women

Breast cancer risk is strongly related to several reproductive and hormonal factors, but the nature of the effects of endogenous oestrogens has been difficult to establish. Data are now available from several large prospective studies with biobanks of stored serum, enabling better characterization of the associations of endogenous oestrogens, and other endogenous hormones, with breast cancer risk. In postmenopausal women, relatively high serum concentrations of oestradiol are associated with a more than twofold increase in the risk for breast cancer, and this probably explains the increase in risk in obese postmenopausal women. In premenopausal women the data available on oestrogens are more limited and difficult to interpret due to the large variations in endogenous oestrogens during the menstrual cycle, but are compatible with a positive association between oestradiol and breast cancer risk. There is also evidence that breast cancer risk is positively associated with androgens, prolactin and insulin-like growth factor-I. Further data are required, with better assays and repeat measures, to provide more accurate estimates of risk and to clarify the role of oestrogens in premenopausal women and the roles of other endogenous hormones.