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The yellow-necked mouse, Apodemus flavicollis, can be considered as a model for genetic polymorphism produced by the frequent presence of supernumerary or B chromosomes (Bs). Host genetic background is rarely taken into account in studies of parasite sex ratio. The main aim of this study was to investigate the range of infrapopulation sex ratios for nematode parasites of the yellow-necked mouse and to determine which factors most influence variation in parasite sex ratios. Six nematode species found in the collected yellow-necked mice were analysed. We confirmed the predominant pattern of female-biased sex ratios in vertebrate parasite infrapopulations. The presence of B chromosomes in host genomes played an important role in infrapopulations of Heligmosomoides polygyrus, Syphacia stroma and Trichuris muris, as hosts with B chromosomes carried a higher proportion of males. The relative increase of males in infrapopulations could result from a shift in parasite life history strategy, induced by adaptation to the specific host genotypes (Bs present). In a meta-analysis with previously published data, the sex determination system was demonstrated to play a significant role in nematode sex ratio variation, as well as specific life history patterns, such as the place of egg hatching.
Up to six nematode species were identified from 86 specimens of the yellow-necked field mouse Apodemus flavicollis from three mountainous localities known as Avala, Cer and Liškovac in Serbia. The highest prevalence of infection of 97% was recorded from Mt. Avala. Only one nematode species, Syphacia frederici, occurred in all three localities. There was complete overlap in nematode species from Mts. Avala and Liškovac, whereas the taxonomic distinctness of Mt. Cer was seen in the presence of the insect-transmitted species Rictularia proni. Locality was a statistically significant factor in all the best-fitted generalized linear models of variation in abundances. The highest level of both species richness and parasite alpha diversity (Shannon's H= 1.47) was found in the easternmost Mt. Liškovac, whereas the diversity indices were lowest for the westernmost Mt. Cer (Shannon's H= 0.48). In view of this geographical difference, the beta diversity indices were calculated along a west to east longitudinal gradient.
Loess deposits in the Vojvodina region, northern Serbia, are among the oldest and most complete loess-paleosol sequences in Europe to date. These thick sequences contain a detailed paleoclimatic record from the late Early Pleistocene. Based on the correlation of detailed magnetic susceptibility (MS) records from Vojvodina with the Chinese loess record and deep-sea isotope stratigraphy we here reconfirm and expand on a stratigraphic model of the Vojvodinian loess-paleosol chronostratigraphic sequence following the Chinese loess stratigraphic system.
Variations in MS, dust accumulation rates, and the intensity of pedogenesis demonstrate evidence for a Middle Pleistocene climatic and environmental transition. The onset of loess deposition in Vojvodina also indicates a direct link between dust generation in Europe and that in the interior of Eurasia since the Early Pleistocene. The youngest part of the Early Pleistocene and oldest part of the Middle Pleistocene is characterised by relatively uniform dust accumulation and soil formation rates as well as relatively high magnetic susceptibility values. In contrast, the last five interglacial-glacial cycles are characterised by sharp environmental differences between high dust accumulation rates during the glacials and low rates observed during soil development. The data presented in this study demonstrate the great potential of Vovjodina's loess archives for accurate reconstruction of continental Eurasian Pleistocene climatic and environmental evolution.
Post-traumatic stress disorder (PTSD) develops in a minority of traumatized individuals. Attention biases to threat and abnormalities in fear learning and extinction are processes likely to play a critical role in the creation and/or maintenance of PTSD symptomatology. However, the relationship between these processes has not been established, particularly in highly traumatized populations; understanding their interaction can help inform neural network models and treatments for PTSD.
Attention biases were measured using a dot probe task modified for use with our population; task stimuli included photographs of angry facial expressions, which are emotionally salient threat signals. A fear-potentiated startle paradigm was employed to measure atypical physiological response during acquisition and extinction phases of fear learning. These measures were administered to a sample of 64 minority (largely African American), highly traumatized individuals with and without PTSD.
Participants with PTSD demonstrated attention biases toward threat; this attentional style was associated with exaggerated startle response during fear learning and early and middle phases of extinction, even after accounting for the effects of trauma exposure.
Our findings indicate that an attentional bias toward threat is associated with abnormalities in ‘fear load’ in PTSD, providing seminal evidence for an interaction between these two processes. Future research combining these behavioral and psychophysiological techniques with neuroimaging will be useful toward addressing how one process may modulate the other and understanding whether these phenomena are manifestations of dysfunction within a shared neural network. Ultimately, this may serve to inform PTSD treatments specifically designed to correct these atypical processes.
The ability to effectively regulate emotions and a secure attachment style are critical for maintaining mental health across the life span. The experience of childhood maltreatment interferes with normal development of emotional regulation and dramatically increases risk for a wide range of psychiatric disorders in adulthood. The central nervous system oxytocin systems are critically involved in mediating social attachment and buffering psychophysiological responses to stress. We therefore investigated the impact of childhood maltreatment and an oxytocin receptor (OXTR) single nucleotide polymorphism (rs53576) and their interaction on emotional dysregulation and attachment style in adulthood in a sample of low-income, African American men and women recruited from primary care clinics of an urban, public hospital. Consistent with prior research, we found that the severity of childhood maltreatment was associated with increased levels of emotional dysregulation in adulthood. Childhood maltreatment was also positively associated with ratings of disorganized/unresolved adult attachment style and negatively associated with ratings of secure adult attachment style. There was no direct association between rs53576 and emotional dysregulation or ratings of adult attachment style. However, there were significant interactions between rs53576 and childhood maltreatment in predicting level of adult emotional dysregulation and attachment style. Specifically, G/G genotype carriers were at risk for increased emotional dysregulation when exposed to three or more categories of childhood abuse. In addition, G/G genotype carriers exhibited enhanced disorganized adult attachment style when exposed to severe childhood abuse compared to A/A and A/G carriers. Our findings suggest that A allele carriers of OXTR rs53576 are resilient against the effects of severe childhood adversity, by protection against emotional dysregulation and disorganized attachment.
Silicon-on-insulator (SOI) regions have been grown on lithographically predetermined positions by Al-mediated Solid-Phase Epitaxy (SPE) of amorphous silicon (α-Si). A controllable Si lateral overgrowth is induced from windows formed in silicon dioxide (SiO2) to the crystalline Si substrate. The resulting hundred of-nanometer large areas of high-quality monocrystalline SOI are formed at the temperatures that can be as low as 400 °C. The as-obtained SOI regions were found to take on the same crystal orientation as the (100) Si substrate and have the ability to merge seamlessly over the oxide.
The amplitude modulation of a finite amplitude drift wave by zonal flows in a non-uniform magnetoplasma is considered. The evolution of a nonlinearly coupled drift wave-zonal flow (DW-ZF) system is governed by a nonlinear equation for the slowly varying envelope of the drift waves, which drives (via the Reynolds stress of the drift wave envelope) the second equation for zonal flows. The nonlinear dispersion relation for the modulational instability of a drift wave pump is derived and analyzed. In a special case, the DW-ZF system of equations reduces to the cubic nonlinear Schrödinger equation, which admits localized solutions in the form of DW envelope solitons, accompanied by a shock-like ZF structure. Numerical solutions of the nonlinearly coupled DW-ZF systems reveal that an arbitrary spatial distribution of the DW rapidly decays into an array of localized drift wave structures, propagating with different speeds, that are robust and, in many respect, behave as solitons. The corresponding ZF evolves into the sequence of shocks that produces a strong shearing, i.e. multiple plasma flows in alternating directions.
Over a 9-day period in February 1995, 16 newborn babies (age range 2–11 days) and 3 infants (24, 47 and 180 days of age) in a neonatal nursery ward developed diarrhoea accompanied by pyrexia and weight loss. Known enteropathogens were not detected in their stools but Escherichia coli displaying aggregative adherence to HEp-2 cells (enteroaggregative E. coli) were found in 12 (63%) ill infants and in none of 5 well neonates (P = 0·02). The illness lasted 3–9 days (mean 5·2) in 16 babies, whereas in 3 neonates it showed a protracted course of 18–20 days. The source of infection and the mode of transmission remained unclear. The outbreak isolates manifested properties common in this new group of diarrhoeagenic E. coli: mannose-resistant haemagglutination, haemolysis on blood agar, and clump formation in liquid culture medium. They belonged to the O4 E. coli serogroup and expressed multiple antibiotic resistance.
Starting from the hydrodynamic equations for a cold electron fluid, we develop a theory of the ponderomotive effect of the interaction of high-frequency electromagnetic radiation with a magneto-active plasma. Using the method of averaging on high-frequency oscillations, we obtain expressions for the low- frequency nonlinear currents. We also obtain an equation describing the space–time evolution of a quasi-stationary magnetic field in the plasma.
Consideration of near-wall turbulence in the functional space that emphasizes the level of anisotropy of the velocity fluctuations not only provides an understanding of th causative physics behind remarkable effects of turbulent drag reduction, but also lead to the logical design of a surface topology which is shown experimentally to be capable o producing a significant reduction of viscous drag which far exceeds what has been achieved so far.
A central goal of flow control is to minimize the energy consumption in turbulent flows and nowadays the best results in terms of drag reduction are obtained with the addition of long-chain polymers. This has been found to be associated with increased anisotropy of turbulence in the near-wall region. Other drag reduction mechanisms are analysed in this respect and it is shown that close to the wall highly anisotropic states of turbulence are commonly found. These findings are supported by results of direct numerical simulations which display high drag reduction effects of over 30% when only a few points inside the viscous sublayer are forced towards high anisotropy.
The paper presents milk production results in a domestic Balkan goat breed reared in the north-western region of the Sharplanina massif. A characteristic of the domestic Balkan goat is that it is reared under poor conditions where other domestic animals can not find enough food to survive. These goats have a strong constitution, are robust and resistent to contagious and parasitic diseases, tolerant to hot, arid climate, and have modest nutritional requirements. The entire body (except the nose, hoofs, and lower portion of the tail) is covered by hair. Hair color varies. Most often it is reddish or gray, but can also be black, as well as chestnut, brown, patchy, and seldom, white. Body size increases with age, due to the fact that the domestic Balkan goat matures late, reaching full size at about 4 years of age. Mean values for height at withers and body length in mature goats were 66 and 70 cm, respectively. Lactation duration was 238 days, total milk production 178 kg per lactation, milk fat 3.68%. An average of 1.2 kids are obtained per goat annualy. Poor fertility of the domestic Balkan goat is caused by numerous reasons, mainly poor nutrition.
Through lack of data, knowledge of primary copper mining has remained for a long time unclear (Bognár-Kutzián 1976, 75; Sherratt 1975, 577). For the same reason, comparisons with the mining of flint, well known in Central and Western Europe, were not possible. This lack of direct knowledge of copper mining has meant that theories concerning the origins of copper metallurgy have been based largely on the results of examination of various copper objects (Tylecote 1976, 5; Rowlands 1971, 210).
Recent excavations carried out in SE Europe underline the importance of mining as a new element in the investigation of the beginning of copper metallurgy. Two sites are foremost: Ai Bunar in South Bulgaria and Rudna Glava in North-East Yugoslavia (fig. 1). Mining works of considerable size, attested at Ai Bunar, have not been completely examined (see now Cernych 1978, not available when this report was prepared). According to the published results, it seems to be a combination of open-cast and shaft extraction; the places of exploitation are numerous—eleven of them have been investigated—but this may not be the final total. An ore bed of copper carbonate minerals, mainly malachite and to a lesser extent azurite, has been exposed for a distance of 1·5 km (Cernych 1975, 133; Cernych 1978).
The earliest finds of copper objects in the Vinča group were made as early as the first half of this century, during the excavation of the eponymous site of Vinča-Belo Brdo, near Belgrade. Amongst other objects, a small group of oval beads was found at a depth of 6-6m, in a habitation level representing the beginning of the Vinča-Plocnik, or late, phase of this group (Vasić 1936, 43).
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