Sexual dimorphism in growth in the relative length of the forearm and relative knee height during adolescence

There are numerous studies concerning sexual dimorphism in body proportions, but only a few have investigated growth in the relative length of particular segments of the upper and lower limbs during adolescence. The aim of the study is an assessment of sex differences of longitudinal growth in the relative length of the forearm and knee height among adolescents. Sample involved 121 boys and 111 girls, participants of the Wroclaw Growth Study, examined annually between 8 and 18 years of age. Sexual dimorphism in six ratios: forearm length and knee height relatively to: trunk, height, and limb length were analyzed using a two‐way analysis of variance with repeated measurements. The sex and age relative to an estimate of maturity timing (3 years before, and after age class at peak height velocity [PHV]) were independent variables. All of the ratios showed significant sex differences in interaction with age relative to age at PHV. The relative length of the forearm, in boys, did not change significantly with the years relative to age at PHV, whereas in girls, was the lowest in the two first age classes and afterward significantly increased just 1 year before and during the adolescent growth spurt, remaining unchanged in further age classes. For relative knee height no clear pattern for sex differences was noticed. It is proposed that relatively longer forearms, particularly in relation to the trunk in girls, could have evolved as an adaptation to more efficient infant carrying and protection during breastfeeding.     

Study of the Serum Copper Levels in Patients with Major Depressive Disorder

Copper may be involved in the pathophysiology of depression. Clinical data on this issue are very limited and not conclusive. The purpose of the study was to determine the copper concentration in the serum of patients with major depressive disorder and to discuss its potential clinical usefulness as a biomarker of the disease. A case–control clinical study included 69 patients with current depressive episode, 45 patients in remission and 50 healthy volunteers. Cu concentration was measured by electrothermal atomic absorption spectrometry (ETAAS). The mean serum copper level in depressed patients was slightly lower (by 11 %; not statistically significant) than in the control group. Furthermore, there was no significant difference in Cu²⁺ concentration between depressive episode and remission, nor between remission and control group. In the remission group were observed significant correlations between copper levels and the average number of relapses over the past years or time of remission. There was no correlation between serum copper and severity of depression, as measured by HDRS and MADRS. The obtained results showed no significant differences between the copper concentration in the blood serum of patients (both with current depressive episode and in remission) and healthy volunteers, as well as the lack of correlations between the copper level in the active stage of the disease and clinical features of the population. Our study is the first conducted on such a large population of patients, so the results may be particularly important and reliable source of knowledge about the potential role of copper in depression.     

High fitness costs of climate change‐induced camouflage mismatch

Anthropogenic climate change has created myriad stressors that threaten to cause local extinctions if wild populations fail to adapt to novel conditions. We studied individual and population‐level fitness costs of a climate change‐induced stressor: camouflage mismatch in seasonally colour molting species confronting decreasing snow cover duration. Based on field measurements of radiocollared snowshoe hares, we found strong selection on coat colour molt phenology, such that animals mismatched with the colour of their background experienced weekly survival decreases up to 7%. In the absence of adaptive response, we show that these mortality costs would result in strong population‐level declines by the end of the century. However, natural selection acting on wide individual variation in molt phenology might enable evolutionary adaptation to camouflage mismatch. We conclude that evolutionary rescue will be critical for hares and other colour molting species to keep up with climate change.     

Conservation genetics: Linking science with practice

Conservation genetics is a well‐established scientific field. However, limited information transfer between science and practice continues to hamper successful implementation of scientific knowledge in conservation practice and management. To mitigate this challenge, we have established a conservation genetics community, which entails an international exchange‐and‐skills platform related to genetic methods and approaches in conservation management. First, it allows for scientific exchange between researchers during annual conferences. Second, personal contact between conservation professionals and scientists is fostered by organising workshops and by popularising knowledge on conservation genetics methods and approaches in professional journals in national languages. Third, basic information on conservation genetics has been made accessible by publishing an easy‐to‐read handbook on conservation genetics for practitioners. Fourth, joint projects enabled practitioners and scientists to work closely together from the start of a project in order to establish a tight link between applied questions and scientific background. Fifth, standardised workflows simplifying the implementation of genetic tools in conservation management have been developed. By establishing common language and trust between scientists and practitioners, all these measures help conservation genetics to play a more prominent role in future conservation planning and management.     

Current and future potential distributions of three Dracaena Vand. ex L. species under two contrasting climate change scenarios in Africa

Forest undergrowth plants are tightly connected with the shady and humid conditions that occur under the canopy of tropical forests. However, projected climatic changes, such as decreasing precipitation and increasing temperature, negatively affect understory environments by promoting light‐demanding and drought‐tolerant species. Therefore, we aimed to quantify the influence of climate change on the spatial distribution of three selected forest undergrowth plants, Dracaena Vand. ex L. species, D. afromontana Mildbr., D. camerooniana Baker, and D. surculosa Lindl., simultaneously creating the most comprehensive location database for these species to date. A total of 1,223 herbarium records originating from tropical Africa and derived from 93 herbarium collections worldwide have been gathered, validated, and entered into a database. Species‐specific Maxent species distribution models (SDMs) based on 11 bioclimatic variables from the WorldClim database were developed for the species. HadGEM2‐ES projections of bioclimatic variables in two contrasting representative concentration pathways (RCPs), RCP2.6 and RCP8.5, were used to quantify the changes in future potential species distribution. D. afromontana is mostly sensitive to temperature in the wettest month, and its potential geographical range is predicted to decrease (up to ?63.7% at RCP8.5). Optimum conditions for D. camerooniana are low diurnal temperature range (6–8°C) and precipitation in the wettest season exceeding 750 mm. The extent of this species will also decrease, but not as drastically as that of D. afromontana. D. surculosa prefers high precipitation in the coldest months. Its potential habitat area is predicted to increase in the future and to expand toward the east. This study developed SDMs and estimated current and future (year 2050) potential distributions of the forest undergrowth Dracaena species. D. afromontana, naturally associated with mountainous plant communities, was the most sensitive to predicted climate warming. In contrast, D. surculosa was predicted to extend its geographical range, regardless of the climate change scenario.     

Effect of weight and storage time of broiler breeders’ eggs on morphology and biochemical features of eggs,embryogenesis, hatchability,and chick quality

The transfer of hatchability results obtained under experimental conditions to the commercial ground with a positive financial effect proves the value and usefulness of these data. On the other hand, finding results on commercial processes of broiler breeders’ egg incubation in the literature is challenging. The presented study aimed to determine the effects of egg weight and storage time on the physical, biochemical characteristics of hatching eggs, embryogenesis and hatchability in Ross 308 broiler breeders. On the laying day, the eggs were divided into four weight groups: S – small eggs (57–61 g), M – medium eggs (62–66 g), L – large eggs (67–71 g), and XL – extra-large eggs (72–76 g). The eggs were then stored for 3, 7, 14, and 21 days under controlled conditions. As the egg storage time increased, a decrease in the yolk quality (lower index) was observed. The highest Haugh units were found in eggs from the S and M groups. The cholesterol content of the M, L, and XL groups was lower on days 7, 14, and 21 as compared to that of eggs only stored for 3 days. Egg weight loss during incubation decreased with an increase in the egg weight. An extension of the egg storage time caused an increase in the loss of egg weight. On the 14th and 18th days of hatching, an increase in the eggshell temperature was noted with an increase in the weight of the egg. The eggs stored for 7 days were characterised by the highest shell temperature on each day. The highest hatchability percentage was recorded for the M group. The hatchability rate decreased with the prolongation of the storage time, while the number of crippled chicks after hatching increased. The results confirmed that the increased weight of the eggs and prolonged storage time (14 and 21 days) increased the weight and decreased the length of the newly hatched chicks, respectively. Chicks from the heaviest eggs and those stored for 14 and 21 days showed poor results on the Pasgar score® test. The observations indicate the need to adopt various (of those available) methods to assess the quality of newly hatched chicks in hatcheries in order to produce high-quality broiler chickens. The results also indicate that prolonged egg storing beyond 14 days may affect the thyroid hormone economy during the hatching of chicks, especially in the XL group.     

Transforming the dilemma

How does natural selection lead to cooperation between competing individuals? The Prisoner's Dilemma captures the essence of this problem. Two players can either cooperate or defect. The payoff for mutual cooperation, R, is greater than the payoff for mutual defection, P. But a defector versus a cooperator receives the highest payoff, T, where as the cooperator obtains the lowest payoff, S. Hence, the Prisoner's Dilemma is defined by the payoff ranking T > R > P > S . In a well‐mixed population, defectors always have a higher expected payoff than cooperators, and therefore natural selection favors defectors. The evolution of cooperation requires specific mechanisms. Here we discuss five mechanisms for the evolution of cooperation: direct reciprocity, indirect reciprocity, kin selection, group selection, and network reciprocity (or graph selection). Each mechanism leads to a transformation of the Prisoner's Dilemma payoff matrix. From the transformed matrices, we derive the fundamental conditions for the evolution of cooperation. The transformed matrices can be used in standard frameworks of evolutionary dynamics such as the replicator equation or stochastic processes of game dynamics in finite populations.     

Locally enhanced sampling molecular dynamics study of the dioxygen transport in human cytoglobin

Cytoglobin (Cyg)--a new member of the vertebrate heme globin family--is expressed in many tissues of the human body but its physiological role is still unclear. It may deliver oxygen under hypoxia, serve as a scavenger of reactive species or be involved in collagen synthesis. This protein is usually six-coordinated and binds oxygen by a displacement of the distal HisE7 imidazole. In this paper, the results of 60 ns molecular dynamics (MD) simulations of dioxygen diffusion inside Cyg matrix are discussed. In addition to a classical MD trajectory, an approximate Locally Enhanced Sampling (LES) method has been employed. Classical diffusion paths were carefully analyzed, five cavities in dynamical structures were determined and at least four distinct ligand exit paths were identified. The most probable exit/entry path is connected with a large tunnel present in Cyg. Several residues that are perhaps critical for kinetics of small gaseous diffusion were discovered. A comparison of gaseous ligand transport in Cyg and in the most studied heme protein myoglobin is presented. Implications of efficient oxygen transport found in Cyg to its possible physiological role are discussed.