Energy exploitation in Chirocephalus croaticus (Steuer, 1899) (Crustacea: Anostraca): survival strategy in an intermittent lake

Electron transport system (ETS) activity was measured in Chirocephalus croaticus from the intermittent lake, Petelinjsko Jezero. The ETS activities were measured at 5, 10, 15, 20, and 25 °C, and were studied separately in juveniles, females and males. Juveniles had significantly higher activity than adults at a standard temperature of 20 °C. The mass-specific ETS activity decreased with increasing size of the animals; the value b was 0.787. Respiration rates (R) were determined at 20 °C and the ratio ETS/R (±standard deviation) for C. croaticus was 1.43±0.46 (n=38). ETS activity increased with temperature. Females had higher Q₁₀ than males in higher temperature range (t-test; t=2.50; d.f.=8; p<0.05). Activation energy E_a was higher for females than males (t-test; t=2.35; d.f.=8; p<0.05). Females exhibited lower ETS activity than males over the lower temperature range, but their ETS could function more efficient at higher temperature.     

Experience with using Ellenberg’s <Emphasis Type=Italic>R</Emphasis> indicator values in Slovakia: Oligotrophic and mesotrophic submontane broad-leaved forests

Ellenberg’s indicator values have been suggested as useful method of estimating site conditions using plants. We examined whether Ellenberg’s R values are suitable for indicating soil reaction and if calibration to physical pH measurements can improve bioindication in oligotrophic and mesotrophic submontane broad-leaved forests in Slovakia. Vegetation relevés and pH-H₂O and pH-CaCl₂ soil reaction were recorded for this purpose. Ellenberg’s R values (R _e) were compared to Jurko’s indicator values (R _j) and a set of species R values and tolerances (T), which were calibrated with physical pH data using the weighted averaging (R _w, T _w) and Huisman-Olff-Fresco modelling (R _h, T _h). Original R _e values were then recalibrated with measured pH data to establish new, adjusted set of scores (R _c, T _c) at Ellenberg’s scale. The Re values are significantly correlated with the other R values, and they demonstrate similar frequency distribution to R _j and R _w values for the studied species pool. The frequency distribution becomes similar across all the R values when indifferent species were excluded. The performance of all the indicator values in terms of bioindication was tested. Relevé means of the R values were regressed on the field pH measurements. The performance of bioindication varied from 36% to 49% of the explained variance for pH-CaCl₂, with the R _e and R _c values yielding 46% and 49% respectively. The bioindication slightly improved for all calibrated methods (R _w, R _h and R _c) when species were weighted inversely with their tolerances — the performance varied from 42% to 51%, and the R _c values performed most effectively. We concluded that Ellenberg’s R values represent a powerful system for bioindicating soil acidity when compared to the other alternatives, with pH-CaCl₂ showing better results than pH-H₂O. Recalibration of Ellenberg’s values to the measured data improved the indicator system.     

Environmental margin and island evolution in Middle Eastern populations of the Egyptian fruit bat

Here, we present a study of the population genetic architecture and microevolution of the Egyptian fruit bat (Rousettus aegyptiacus) at the environmental margins in the Middle East using mitochondrial sequences and nuclear microsatellites. In contrast to the rather homogenous population structure typical of cave‐dwelling bats in climax tropical ecosystems, a relatively pronounced isolation by distance and population diversification was observed. The evolution of this pattern could be ascribed to the complicated demographic history at higher latitudes related to the range margin fragmentation and complex geomorphology of the studied area. Lineages from East Africa and Arabia show divergent positions. Within the northwestern unit, the most marked pattern of the microsatellite data set is connected with insularity, as demonstrated by the separate status of populations from Saharan oases and Cyprus. These demes also exhibit a reduction in genetic variability, which is presumably connected with founder effects, drift and other potential factors related to island evolution as site‐specific selection. Genetic clustering indicates a semipermeability of the desert barriers in the Sahara and Arabian Peninsula and a corridor role of the Nile Valley. The results emphasize the role of the island environment in restricting the gene flow in megabats, which is also corroborated by biogeographic patterns within the family, and suggests the possibility of nascent island speciation on Cyprus. Demographic analyses suggest that the colonization of the region was connected to the spread of agricultural plants; therefore, the peripatric processes described above might be because of or strengthened by anthropogenic changes in the environment.     

Atherosclerotic lesions of supra-aortic arteries in diabetic patients

The aim of this prospective study was to determine the prevalence and localization of stenotic atherosclerotic lesions of supra-aortic arteries in diabetic patients according to age and sex. Angiograms obtained by digital subtraction angiography were analyzed in 150 diabetic patients (study group) and 150 non-diabetic patients (control group) with symptoms of cerebral ischemia. Diabetic patients were found to have a significantly higher prevalence of stenotic atherosclerotic lesions of the internal carotid artery. Lesions of the large supra-aortic arteries were significantly more common in the left than in the right side of the neck (p < 0.001), but the difference between the diabetic and the non-diabetic group did not reach statistical significance. Hemodynamic conditions were found to be more important than diabetes for the occurrence of atherosclerotic lesions in these arteries. Changes in the proximal segment of the left common carotid artery were the most common finding in diabetic patients, hence attention should be paid to this localization on control examinations.     

Soil chemical properties affect the concentration of elements (N,P, K,Ca, Mg,As, Cd,Cr, Cu,Fe, Mn,Ni, Pb,and Zn) and their distribution between organs of Rumex obtusifolius

Background and aims

The ionome (elemental composition) of grassland species has rarely been studied at the level of individual organs and little is known about effects of soil chemical properties on the ionome. Using the model oxalate plant Rumex obtusifolius, we asked how its biomass production and the distribution of elements between its organs is affected by soil chemical properties.

Methods

We established a pot experiment with R. obtusifolius planted in acidic non-contaminated control and in slightly acidic and alkaline soils anthropogenically contaminated by the risk elements As, Cd, Pb, and Zn. Both contaminated soils were untreated and treated by lime and superphosphate. We determined biomass production and the concentrations of elements in its organs.

Results

Biomass production was negatively related to the mobility of micro- and risk elements. Restricted transport of micro- and risk elements from belowground organs into leaves was recorded in untreated contaminated soils. In both lime-treated soils and in superphosphate-treated alkaline soil, elevated transport of micro- and risk elements from belowground organs into leaves was recorded in comparison to untreated contaminated soils. The lowest concentrations of micro- and risk elements were recorded in stems and seeds, followed by belowground organs and leaves.

Conclusions

R. obtusifolius is an As-, Cd-, Pb-, and Zn-excluder and is sensitive to high availability of micro- and risk elements in the soil. Soil chemical properties affect the distribution of essential elements within the plant greatly.     

Non-equilibrium allele frequency spectra via spectral methods

A major challenge in the analysis of population genomics data consists of isolating signatures of natural selection from background noise caused by random drift and gene flow. Analyses of massive amounts of data from many related populations require high-performance algorithms to determine the likelihood of different demographic scenarios that could have shaped the observed neutral single nucleotide polymorphism (SNP) allele frequency spectrum. In many areas of applied mathematics, Fourier Transforms and Spectral Methods are firmly established tools to analyze spectra of signals and model their dynamics as solutions of certain Partial Differential Equations (PDEs). When spectral methods are applicable, they have excellent error properties and are the fastest possible in high dimension; see Press et al. (2007). In this paper we present an explicit numerical solution, using spectral methods, to the forward Kolmogorov equations for a Wright–Fisher process with migration of K populations, influx of mutations, and multiple population splitting events.     

Water-Induced Finger Wrinkles Do Not Affect Touch Acuity or Dexterity in Handling Wet Objects

Human non-hairy (glabrous) skin of the fingers, palms and soles wrinkles after prolonged exposure to water. Wrinkling is a sympathetic nervous system-dependent process but little is known about the physiology and potential functions of water-induced skin wrinkling. Here we investigated the idea that wrinkling might improve handling of wet objects by measuring the performance of a large cohort of human subjects (n = 40) in a manual dexterity task. We also tested the idea that skin wrinkling has an impact on tactile acuity or vibrotactile sensation using two independent sensory tasks. We found that skin wrinkling did not improve dexterity in handling wet objects nor did it affect any aspect of touch sensitivity measured. Thus water-induced wrinkling appears to have no significant impact on tactile driven performance or dexterity in handling wet or dry objects.