Family size,the physical environment,and socioeconomic effects across the stature distribution

A neglected area in historical stature studies is the relationship between stature and family size. Using robust statistics and a large 19th century data set, this study documents a positive relationship between stature and family size across the stature distribution. The relationship between material inequality and health is the subject of considerable debate, and there was a positive relationship between stature and wealth and an inverse relationship between stature and material inequality. After controlling for family size and wealth variables, the paper reports a positive relationship between the physical environment and stature.     

Analysis of the community structure of yeasts associated with the decaying stems of cactus. I.Stenocereus gummosus

Yeast communities of decayingStenocereus gummosus were analyzed for spatial, temporal, and physiological characteristics. Analysis of random samples within plants, between plants, and between localities shows that the species proportions of the yeast community are relatively constant within plants and between localities, but that there is significant variability between rotting plants. It is suggested that the increased variability between plants represents sampling of different stages of succession. The physiological abilities of the yeast community also show a relatively constant pattern within plants and between localities yet more variability between plants.The variablity profiles of species proportions and community physiological characters are demonstrated to be correlated within and between plants. This observation is an extension of the Kluge-Kerfoot phenomenon to the level of the community. The correlation of within and between plant variability profiles is suggested to be a result of the temporal and spatial availability of resources during the stages of rotting plant succession. The community structure is thus postulated to result from a set of possible future resource states of the habitat.     

Interaction between Intrinsically Disordered Proteins Frequently Occurs in a Human Protein-Protein Interaction Network

Intrinsic protein disorder is a widespread phenomenon characterised by a lack of stable three-dimensional structures and is considered to play an important role in protein-protein interactions (PPIs). This study examined the genome-wide preference of disorder in PPIs by using exhaustive disorder prediction in human PPIs. We categorised the PPIs into three types (interaction between disordered proteins, interaction between structured proteins, and interaction between a disordered protein and a structured protein) with regard to the flexibility of molecular recognition and compared these three interaction types in an existing human PPI network with those in a randomised network. Although the structured regions were expected to become the identifiers for binding recognition, this comparative analysis revealed unexpected results. The occurrence of interactions between disordered proteins was significantly frequent, and that between a disordered protein and a structured protein was significantly infrequent. We found that this propensity was much stronger in interactions between nonhub proteins. We also analysed the interaction types from a functional standpoint by using GO, which revealed that the interaction between disordered proteins frequently occurred in cellular processes, regulation, and metabolic processes. The number of interactions, especially in metabolic processes between disordered proteins, was 1.8 times as large as that in the randomised network. Another analysis conducted by using KEGG pathways provided results where several signaling pathways and disease-related pathways included many interactions between disordered proteins. All of these analyses suggest that human PPIs preferably occur between disordered proteins and that the flexibility of the interacting protein pairs may play an important role in human PPI networks.     

Relationships among element contents in the medial meniscus

To elucidate compositional changes of elements in the meniscus with aging, the authors investigated the relationships among elements in the medial meniscus by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of 16 men and 7 women, ranging in age from 65 to 93 yr. In the left medial meniscus, extremely significant correlations were found both between calcium and phosphorus contents and between sulfur and magnesium contents, whereas significant correlations were found between calcium and either iron or zinc contents, between phosphorus and either iron or zinc contents, and between iron and zinc contents. On the other hand, in the right medial meniscus, there were only an extremely significant correlation between calcium and phosphorus contents and a significant correlation between sulfur and magnesium contents. The common finding between the left and right medial menisci was an extremely significant correlation between calcium and phosphorus contents and a significant correlation between sulfur and magnesium contents.     

A gaussian model for substrates of entangled cross-linked poly(ethylene glycol) in biomedical applications

Cells usually spread on a synthetic substrate through bonds between receptors and chemical groups on the substrate (ligands). Therefore, it is valuable to study the effects of the average number density of these chemical groups and the average distance between them to model and predict the cell behavior. Poly(ethylene glycol) [PEG] modified with peptide groups has been used widely in biomedical applications as a substrate material. In this study, a coarse-grained model is proposed for PEG to predict the average number density of ligands and the average distance between them. Molecular information such as initial molecular weight distribution, average molecular weight between cross-links, and average molecular weight between entanglements is used as input parameters. Based on simulation results, it is concluded that both entanglement and cross-link densities are required to create a network structure. The results suggest that an average initial molecular weight 2-3 times the average molecular weight between entanglements and a moderate cross-link density are sufficient to create a closed network structure with a high ligand density and a small average distance between them.     

心肌细胞团搏动的整数倍节律的实验观察

实验报道了心肌细胞团自发性同步化搏动的一类新节律——整数倍节律。这种稳定的节律模式由两种相关的搏动形式的随机交替出现形成,这两种搏动形式中任何一种的出现间期具有整数倍特征。在静息状态和周期1搏动间的随机交替形成0-1整数倍节律,在周期1搏动和周期2搏动之间的随机交替形成l-2整数倍节律。0-1整数倍是居于静息状态和周期1节律之间的节律模式,1-2整数倍是居于周期1节律和周期2节律之间的节律模式,实验所见的节律转迁过程清楚地展示了静息状态、0-1整数倍节律、周期1节律、1-2整数倍节律、周期2节律等顺序地构成的一种“节律谱系”。“节律谱系”的观念可以为认识正常和异常心律的关系和其间的转迁机制提供深刻的理论启示。     

Repeatability of hematocrits and body mass of Gray Catbirds

ABSTRACT.   Hematocrits may provide information about the physiological condition of birds, but, to be a useful measure, information is needed concerning how hematocrits vary among individuals and over time. We examined the repeatability of hematocrits in a population of Gray Catbirds ( Dumetella carolinensis ) in Pennsylvania at several time scales and also examined the repeatability of body mass, another measure commonly used as an indicator of condition. Both hematocrit ( r = 0.64) and mass ( r = 0.65) were repeatable ( P < 0.01) for first captures between years and between first and second captures within a year ( r = 0.41 and r = 0.50, respectively; P < 0.01), but not repeatable ( P > 0.05) between captures in different months within a year ( r = 0.11 for both). Repeatability of both measures differed by sex and age. Females exhibited repeatability of hematocrit and body mass only between years, while male hematocrits were repeatable between years and between first and second captures within a season. Male mass was repeatable for all time periods. Hematocrits of younger birds were repeatable between captures within a season and their body mass was repeatable between months and weeks while hematocrits of older birds were not repeatable and their body mass was repeatable only between captures in a season. Our results indicate that hematocrits and body mass had similar repeatability coefficients overall, but that hematocrits of Gray Catbirds were a consistent trait of individuals only across years. Because repeatability between captures and months depended on sex and age, we conclude that the hematocrit is a useful measure of individual performance only in limited circumstances.     

Electrical pulses appear in the inferior vena cava and abdominal aorta at contraction of leg muscles.

A vascular-interstitial neuromuscular closed circuit is described anatomically and electrically. The neuromuscular unit has a high resistance due to its axons. The "outer" vascular-interstitial branch has a low resistance due to a large cross section area. When a rat spontaneously contracts leg muscles after pinching a toe, electric potential pulses appear inside the inferior vena cava, between vena cava and peritoneum, between aorta and peritoneum, between vena cava and peritoneum and between aorta and subcutis. Minor pulses between electrodes in the peritoneal fluid are interpreted as induced by the intravascular potential pulses. The use of Ag-AgCl electrodes or platinum electrodes does not appreciably change the results.     

Sex and side differences and correlations between quantitative palmar characteristics in a sample Sardinian population

Differences between the sexes and between the sides and the correlations between four quantitative characteristics of palmar dermatoglyphics in a sample population of 809 individuals (418 males and 391 females) from the city of Cagliari, Sardinia, are tested. Males have a greater number of ridges than females, shown by a greater a-b ridge count and A-d ridge count, and a more transverse slope of the main lines, shown by a greater main line index and papillary number. The left palm shows a greater number of ridges than the right palm between the A line and the triradius d and between the triradii a and b, with a lower main line index and papillary number. The a-b ridge count has a negative correlation with the main line index and with the papillary number and a positive one with the A-d ridge count; these correlations are greater in the left palms, especially in the males.     

The Trade-Off between Female Fertility and Longevity during the Epidemiological Transition in the Netherlands

Several hypotheses have been put forward to explain the relationship between women’s fertility and their post-reproductive longevity. In this study, we focus on the disposable soma theory, which posits that a negative relationship between women’s fertility and longevity can be understood as an evolutionary trade-off between reproduction and survival. We examine the relationship between fertility and longevity during the epidemiological transition in the Netherlands. This period of rapid decline in mortality from infectious diseases offers a good opportunity to study the relationship between fertility and longevity, using registry data from 6,359 women born in The Netherlands between 1850 and 1910. We hypothesize that an initially negative relationship between women’s fertility and their longevity gradually turns less negative during the epidemiological transition, because of decreasing costs of higher parities. An initially inversed U-shaped association between fertility and longevity changes to zero during the epidemiological transition. This does suggest a diminishing environmental pressure on fertility. However, we find no evidence of an initial linear trade-off between fertility and post-reproductive survival.     

Sequence variations within protein families are linearly related to structural variations

It is commonly believed that similarities between the sequences of two proteins infer similarities between their structures. Sequence alignments reliably recognize pairs of protein of similar structures provided that the percentage sequence identity between their two sequences is sufficiently high. This distinction, however, is statistically less reliable when the percentage sequence identity is lower than 30% and little is known then about the detailed relationship between the two measures of similarity. Here, we investigate the inverse correlation between structural similarity and sequence similarity on 12 protein structure families. We define the structure similarity between two proteins as the cRMS distance between their structures. The sequence similarity for a pair of proteins is measured as the mean distance between the sequences in the subsets of sequence space compatible with their structures. We obtain an approximation of the sequence space compatible with a protein by designing a collection of protein sequences both stable and specific to the structure of that protein. Using these measures of sequence and structure similarities, we find that structural changes within a protein family are linearly related to changes in sequence similarity.     

Lipid tracers of mycoplasma phylogeny

Comparison of the lipid composition between members of the Mycoplasmatales reveals a striking diversity of lipid structures, not only between the six genera but among species within the same genus. This is in contrast to nearly all other bacterial groups in which members of the same genus possess essentially the same lipids. There are in fact more similarities between lipids of a given species of mycoplasma and a genus of bacterium than there are between lipids of a given species of mycoplasma and a genus of bacterium than there are between mycoplasma species. Mycoplasmal lipids suggest that these organisms do not represent a phylogenetically related group at all, but are probably degenerative forms of bacteria, particularly gram-positive bacteria, which have lost the ability to synthesize a cell wall.     

Role of frequency mismatch in neuronal communication through coherence

Neuronal gamma oscillations have been described in local field potentials of different brain regions of multiple species. Gamma oscillations are thought to reflect rhythmic synaptic activity organized by inhibitory interneurons. While several aspects of gamma rhythmogenesis are relatively well understood, we have much less solid evidence about how gamma oscillations contribute to information processing in neuronal circuits. One popular hypothesis states that a flexible routing of information between distant populations occurs via the control of the phase or coherence between their respective oscillations. Here, we investigate how a mismatch between the frequencies of gamma oscillations from two populations affects their interaction. In particular, we explore a biophysical model of the reciprocal interaction between two cortical areas displaying gamma oscillations at different frequencies, and quantify their phase coherence and communication efficiency. We observed that a moderate excitatory coupling between the two areas leads to a decrease in their frequency detuning, up to ～6 Hz, with no frequency locking arising between the gamma peaks. Importantly, for similar gamma peak frequencies a zero phase difference emerges for both LFP and MUA despite small axonal delays. For increasing frequency detunings we found a significant decrease in the phase coherence (at non-zero phase lag) between the MUAs but not the LFPs of the two areas. Such difference between LFPs and MUAs behavior is due to the misalignment between the arrival of afferent synaptic currents and the local excitability windows. To test the efficiency of communication we evaluated the success of transferring rate-modulations between the two areas. Our results indicate that once two populations lock their peak frequencies, an optimal phase relation for communication appears. However, the sensitivity of locking to frequency mismatch suggests that only a precise and active control of gamma frequency could enable the selection of communication channels and their directionality.     

A neutral model of transcriptome evolution

Microarray technologies allow the identification of large numbers of expression differences within and between species. Although environmental and physiological stimuli are clearly responsible for changes in the expression levels of many genes, it is not known whether the majority of changes of gene expression fixed during evolution between species and between various tissues within a species are caused by Darwinian selection or by stochastic processes. We find the following: (1) expression differences between species accumulate approximately linearly with time; (2) gene expression variation among individuals within a species correlates positively with expression divergence between species; (3) rates of expression divergence between species do not differ significantly between intact genes and expressed pseudogenes; (4) expression differences between brain regions within a species have accumulated approximately linearly with time since these regions emerged during evolution. These results suggest that the majority of expression differences observed between species are selectively neutral or nearly neutral and likely to be of little or no functional significance. Therefore, the identification of gene expression differences between species fixed by selection should be based on null hypotheses assuming functional neutrality. Furthermore, it may be possible to apply a molecular clock based on expression differences to infer the evolutionary history of tissues.     

Thermally reversible hydration of beta-chitin

Thermally induced transition between anhydrous and hydrated forms of highly crystalline beta-chitin was studied by differential thermal calorimetry (DSC) and X-ray diffraction. DSC of wet beta-chitin in a sealed pan gave two well-defined endothermic peaks at 85.2 and 104.7 degrees C on heating and one broad exothermic peak at between 60 and 0 degrees C on cooling. These peaks were highly reproducible and became more distinct after repeated heating-cooling cycles. The X-ray diffraction pattern of wet beta-chitin at elevated temperature showed corresponding changes in d-spacing between the sheets formed by stacking of chitin molecules. These phenomena clearly show that water is reversibly incorporated into the beta-chitin crystal and that the temperature change induces transitions between anhydrous, monohydrate, and dihydrate forms. The DSC behavior in heating-cooling cycles, including reversion between the two endothermic peaks, indicated that the transition between monohydrate and dihydrate was a fast and narrow-temperature process, whereas the one between the anhydrous and the monohydrate form was a slow and wide-temperature process.     

Some Applications of the Family of Discrete Exponential Distributions in Biology and Toxicology

In this paper the relationship between the number of males and females in a community, between the number of boys and girls in a family, between the number of animals trapped and untrapped in an animal experiment, between the number of infected and uninfected in an epidemiological study, between the number of mutagens and non-mutagens in a given sample of toxicological experiments, and others, is studied. The general expression for the correlation coefficient, ?, is obtained when N, the community size N, has a discrete exponential family distribution recently studied by Janardan (1980). This is then specialized to some well known discrete distributions.     

Disease evolution across a range of spatio-temporal scales

Traditional explorations of infectious disease evolution have considered the competition between two cross-reactive strains within the standard framework of disease models. Such techniques predict that diseases should evolve to be highly transmissible, benign to the host and possess a long infectious period: in general, diseases do not conform to this ideal. Here we consider a more holistic approach, suggesting that evolution is a trade-off between adaptive pressures at different scales: within host, between hosts and at the population level. We present a model combining within-host pathogen dynamics and transmission between individuals governed by an explicit contact network, where transmission dynamics between hosts are a function of the interaction between the pathogen and the hosts' immune system, though ultimately constrained by the contacts each infected host possesses. Our results show how each of the scales places constraints on the evolutionary behavior, and that complex dynamics may emerge due to the feedbacks between epidemiological and evolutionary dynamics. In particular, multiple stable states can occur with switching between them stochastically driven.     

Mutation and sexual selection: a test using barn swallows from Chernobyl

Abstract Secondary sexual characters have been hypothesized to be particularly susceptible to the deleterious effects of mutation because the expression of such characters is usually influenced by many more metabolic pathways than are ordinary morphological characters. We tested this hypothesis using the elevated mutation rates in the barn swallow ( Hirundo rustica ) of the Chernobyl region of Ukraine as a model system. A great deal is known about the relative importance of different characters for male mating success in this species. The importance of phenotypic characters for male mating success was quantified based on a long-term study of a Danish breeding population, by expressing phenotypic differences between mated and unmated males as the difference between log-transformed mean values. For field samples from Ukraine we likewise expressed the difference in male phenotype between individuals living in a relatively uncontaminated area and individuals from the Chernobyl region as the difference between log-transformed mean values. The standardized difference in male phenotype between the two regions in Ukraine for the 41 different characters was strongly positively correlated with the standardized difference in male phenotype between mated and unmated males from Denmark. The standardized difference in male phenotype between the two regions in Ukraine was significantly positively associated with sexual size dimorphism. However, the standardized difference in male phenotype between mated and unmated males was a much better predictor of standardized difference in male phenotype between the two regions in Ukraine than was the standardized difference in sexual size dimorphism, expressed as the difference between log-transformed mean values for males and females. These findings are consistent with the hypothesis that traits most important for sexual selection are particularly susceptible to the effects of deleterious mutations.     

Intercellular Symplastic Connection and Isolation of the Unloading Zone in Flesh of the Developing Grape Berry

The uhrastructure and intercellular connection of the sugar unloading zone (i. e. the phloem in the dorsal vascular bundle and the phloem-surrounding the assimilate sink-cells) of grape ( Vitis vinifera x V. labrusca cv. Jingchao) berry was observed via transmission electron microscopy. The results showed that during the early developmental stages of grape berry, numerous plasmodesmata were found in the phloem between sieve element (SE) and companion cell (CC), between SE/CC complexes, between SE/CC complex and phloem parenchyma cell and in between phloem parenchyma cells, which made the phloem a symplastic integration, facilitating sugar unloading from sieve elements into both companion cells and phloem parenchyma cells via a symplastic pathway. On the contrary, there was almost no plasmodesma between phloem and its surrounding flesh photoassimilate sink-cells, neither in between the flesh photoassimilate sink-cells giving rise to a symplastic isolation both between phloem and its surrounding flesh photoassimilate sink-cells, as well as among the flesh photoassimilate sink-cells. This indicated that both the sugar unloading from phloem and pestphloem transport of sugars should be mainly via an apoplastic pathway. Dining the ripening stage, most of the plasmodesmata between SE/CC complex and the surrounding phloem parenchyma cells were shown to be blocked by the electron-opaque globules, and a phenomenon of plasmolysis was found in a number of companion cells, indicating a symplastic isolation between SE/CC complex and its surrounding parenchynm cells during this phase. The symplastic isolation between the whole phloem and its surrounding photoassimilate sink-cells during the early developmental stages shifted to a symplastic isolation within the phloem during the ripening phase, and thus the symplastic pathway of sugar unloading from SE/CC complex during the early development stages should be replaced by a dominant apoplastic unloading pathway from SE/CC complex in concordance.     

Relationship between pre‐ and post‐copulatory traits in Salvator rufescens (Squamata: Teiidae)

Understanding pre‐ and post‐copulatory mechanisms of sexual selection can provide insights into the evolution of male reproductive strategies. The phenotype‐linked fertility hypothesis postulates that male sperm quality and secondary sexual characteristics will positively co‐vary, whereas the sperm competition hypothesis predicts a negative association between those traits. Male reproductive traits often show variation throughout the reproductive period, suggesting that the relationship between pre‐ and post‐copulatory sexual selection may vary temporally. Here, we evaluated the relationship between secondary sexual character and sperm traits and its temporal variation in Salvator rufescens, a south American lizard. We observed a negative relationship between jaw muscle and principal piece length of sperm and a variation in the relationship between pre‐ and post‐copulatory traits throughout the reproductive period. Collectively, our results evidenced a trade‐off between pre‐ and post‐copulatory traits and a strong seasonal flexibility of male reproductive strategies in this lizard species.