Measurement of visual acuity and crowding effect in 3–9-year-old children

Visual acuity was measured in 140 3–9-year-old children using Landolt’s rins with a gap in one of four orientations. The influence of surrounding additional contours on the detection of orientation of rings of a minimal visible size was studied in the same children, depending on the distance between the rings and the surrounding. The latter consisted of four bands, located symmetrically with reference to the ring. Visual acuity increased with age, reaching the adult level by approximately seven years. A deterioration of the orientation recognition was detected in all children when the surrounding was close to a ring. The distance that caused a perception deterioration decreased with age, reaching the adult level by nine years. The obtained data are discussed from the viewpoint of a possible influence of individual visual areas formed during ontogeny on task performance.     

Characteristics of bunyavirus- and togavirus-induced nonspecific suppressors inhibiting delayed hypersensitivity

Some properties and mechanisms of action of nonspecific suppressor cells, inhibiting delayed hypersensitivity to sheep red blood cells and activated in vivo in experimental tick-borne encephalitis and Tahyna virus infections in mice, have been studied. These nonspecific suppressor cells have been identified as T-lymphocytes in experiments with the use of antisera to T- and B-lymphocytes. The function of the suppressor cells can be realized without their proliferation and is mediated by a soluble factor whose formation requires the synthesis of protein. In respect to hydrocortisone, the above-mentioned suppressor cells are subdivided into 2 subpopulations: hydrocortisone-resistant in the thymus and hydrocortisone-sensitive in the spleen.     

Geographic mode of speciation in a mountain specialist Avian family endemic to the Palearctic

Mountains host greater avian diversity than lowlands at the same latitude due to their greater diversity of habitats stratified along an elevation gradient. Here we test whether this greater ecological heterogeneity promotes sympatric speciation. We selected accentors (Prunellidae), an avian family associated with mountains of the Palearctic, as a model system. Accentors differ in their habitat/elevation preferences and south‐central Siberia and Himalayan regions each host 6 of the 13 species in the family. We used sequences of the mtDNA ND2 gene and the intron 9 of the Z chromosome specific ACO1 gene to reconstruct a complete species‐level phylogeny of Prunellidae. The tree based on joint analysis of both loci was used to reconstruct the family's biogeographic history and to date the diversification events. We also analyzed the relationship between the node age and sympatry, to determine the geographic mode of speciation in Prunellidae. Our data suggest a Miocene origin of Prunellidae in the Himalayan region. The major division between alpine species (subgenus Laiscopus) and species associated with shrubs (subgenus Prunella) and initial diversification events within the latter happened within the Himalayan region in the Miocene and Pliocene. Accentors colonized other parts of the Palearctic during the Pliocene‐Pleistocene transition. This spread across the Palearctic resulted in rapid diversification of accentors. With only a single exception dating to 0.91 Ma, lineages younger than 1.5 Ma are allopatric. In contrast, sympatry values for older nodes are >0. There was no relationship between node age and range symmetry. Allopatric speciation (not to include peripatric) is the predominant geographic mode of speciation in Prunellidae despite the favorable conditions for ecological diversification in the mountains and range overlaps among species.     

Method for determining kallikrein of tissue origin in blood plasma and its clinical significance

Based on a study of the kininogenase activity of the total plasma kallikrein in the presence of 3 concentrations of the soybean inhibitor trypsin (0.5, 1.0, 10.0 micrograms/ml) one can measure at a time the activity of tissue kallikrein (without specifying the source) and the activity of 3 forms of plasma kallikrein, including its adsorption on kaolin that characterizes the conformational structure of the enzyme. Examination of 10 healthy subjects and 136 patients revealed a 10 to 20-fold increase in the content of tissue kallikrein in plasma of 70% of diabetes mellitus patients and a 2.5 to 3-fold elevation in 50% of patients with chronic occupational bronchitis, and in 30% of patients suffering from chronic hepatitis. The method suggested makes it possible to have a better insight into the physiological and pathogenetic role of the kinin system and may be used for laboratory control over the treatment efficacy.     

Antibody-dependent harmful effect of non-immune spleen cells in acute experimental tick-borne encephalitis in mice

The injection of nonprotective dilutions of immune serum and nonimmune spleen cells into mice infected with tick-borne encephalitis virus induced a sharply pronounced immunopathological effect: the mean survival time of the recipients decreased by 3.6 days in comparison with the control animals. This effect was not linked with the increased replication of the virus in the brain. The antibody-dependent damaging action of spleen cells could be reproduced by using the cells of both syngeneic and allogeneic donors. This phenomenon developed only in those cases when antibodies to the infective agent under study were used. The combination of immune serum to Japanese encephalitis virus and nonimmune spleen cells produced no damaging effect. The hypothesis stating that the antibody-dependent damaging action of nonimmune spleen cells arises from the antibody-dependent cytotoxic action of immunocompetent cells on the infected cells of the central nervous system is discussed.     

Pioneer settlement of the cold-water coral Desmophyllum dianthus (Esper, 1794) on plastic

Coral Reefs - Larval settlement is a critical step for sessile benthic species such as corals, whose ability to thrive on diverse natural and anthropogenic substrates may lead to a competitive...     

Climate change affects winter chill for temperate fruit and nut trees

Background

Temperate fruit and nut trees require adequate winter chill to produce economically viable yields. Global warming has the potential to reduce available winter chill and greatly impact crop yields.

Methodology/Principal Findings

We estimated winter chill for two past (1975 and 2000) and 18 future scenarios (mid and end 21st century; 3 Global Climate Models [GCMs]; 3 greenhouse gas emissions [GHG] scenarios). For 4,293 weather stations around the world and GCM projections, Safe Winter Chill (SWC), the amount of winter chill that is exceeded in 90% of all years, was estimated for all scenarios using the “Dynamic Model” and interpolated globally. We found that SWC ranged between 0 and about 170 Chill Portions (CP) for all climate scenarios, but that the global distribution varied across scenarios. Warm regions are likely to experience severe reductions in available winter chill, potentially threatening production there. In contrast, SWC in most temperate growing regions is likely to remain relatively unchanged, and cold regions may even see an increase in SWC. Climate change impacts on SWC differed quantitatively among GCMs and GHG scenarios, with the highest GHG leading to losses up to 40 CP in warm regions, compared to 20 CP for the lowest GHG.

Conclusions/Significance

The extent of projected changes in winter chill in many major growing regions of fruits and nuts indicates that growers of these commodities will likely experience problems in the future. Mitigation of climate change through reductions in greenhouse gas emissions can help reduce the impacts, however, adaption to changes will have to occur. To better prepare for likely impacts of climate change, efforts should be undertaken to breed tree cultivars for lower chilling requirements, to develop tools to cope with insufficient winter chill, and to better understand the temperature responses of tree crops.     

Mechanical stimulation of the support zones of soles: The method of noninvasive activation of the stepping movement generators in humans

The effects of mechanical stimulation of the soles’ support zones in the modes of slow and fast walking (75 and 120 steps per minute) were studied using the model of supportlessness (legs suspension). 20 healthy subjects participated in the study. EMG activity of hip and shin muscles was recorded. Kinematics of leg movements was assessed with the use of videoanalysis system. In 80% of cases support stimulation was followed by leg movements, in 69% of which they had characteristics of locomotions being accompanied by the burst-like electromyographic activities. The order of involvement of leg muscles and organization of antagonistic muscles activities were analogous to those of voluntary walking. The latencies of electromyographic activity in hip and shin muscles composed 5.17 ± 1.08 and 14.01 ± 2.82 s, respectively, the frequencies of bursts differed significantly depending on stimulation frequency. In 31% of cases the electromyographical activity following the stimulation of the soles’ support zones had not burst-like but uninterrupted pattern. Its amplitude rose smoothly reaching a certain level that was subsequently maintained. Results of the study showed that soles’ support zones stimulation in the mode of locomotion could activate a locomotor generator provoking the appearance of locomotion-like activity and that effect evoked by this stimulation includes not only rhythmical but also non-rhythmical (probably postural) components of walking.