bluuebunny/crossref_metadata_2025 huggingface dataset:
Transsynaptic Activity-Dependent Regulation of Axon Branching and Neurotrophin ExpressionIn Vivo
Authors: Calinescu Anda-Alexandra , Liu Tiecheng , Wang Michael M. , Borjigin Jimo
Published: September 2011

The two major classes of activity-dependent neuroplasticity predict different consequences of activity alteration on circuit response. Hebbian plasticity (positive feedback) posits that alteration of neuronal activity causes a parallel response within a circuit. In contrast, homeostatic plasticity (negative feedback) predicts that altering neuronal activity results in compensatory responses within a circuit. The relative roles of these modes of plasticityin vivoare unclear, since neuronal circuits are difficult to manipulate in the intact organism. In this study, we tested thein vivoeffects of activity deprivation in the superior cervical ganglion–pineal circuit of adult rats, which can be noninvasively silenced by exposing animals to constant light. We demonstrated that total deprivation of sympathetic activity markedly decreased the presence of axonal proteins in the pineal and reduced the density and thickness of sympathetic axonal arbors. In addition, we demonstrated that sympathetic inactivity eliminated pineal function and markedly decreased pineal expression of neurotrophins. Administration of β-adrenergic agonist restored the expression of presynaptic and postsynaptic proteins. Furthermore, compensatory axonal growth through collateral sprouting, normally seen following unilateral denervation of the pineal, was profoundly impaired in the absence of neural activity. Thus, these data suggest that sympathetic axonal terminals are maintained by neural activity that induces neurotrophins, which may act through a retrograde mechanism to preserve the integrity of axonal arbors via a positive feedback loop. Conversely, by using Hebbian-like neuroplasticity, silent yet intact circuits enter a hibernation mode marked by reduction of presynaptic axonal structures and dramatically reduced postsynaptic expression of neurotrophins.
Upregulation of KCC2 Activity by Zinc-Mediated Neurotransmission via the mZnR/GPR39 Receptor
Authors: Chorin Ehud , Vinograd Ofir , Fleidervish Ilya , Gilad David , Herrmann Sharon , Sekler Israel , Aizenman Elias , Hershfinkel Michal
Published: September 2011

Vesicular Zn2+regulates postsynaptic neuronal excitability upon its corelease with glutamate. We previously demonstrated that synaptic Zn2+acts via a distinct metabotropic zinc-sensing receptor (mZnR) in neurons to trigger Ca2+responses in the hippocampus. Here, we show that physiological activation of mZnR signaling induces enhanced K+/Cl−cotransporter 2 (KCC2) activity and surface expression. As KCC2 is the major Cl−outward transporter in neurons, Zn2+also triggers a pronounced hyperpolarizing shift in the GABAAreversal potential. Mossy fiber stimulation-dependent upregulation of KCC2 activity is eliminated in slices from Zn2+transporter 3-deficient animals, which lack synaptic Zn2+. Importantly, activity-dependent ZnR signaling and subsequent enhancement of KCC2 activity are also absent in slices from mice lacking the G-protein-coupled receptor GPR39, identifying this protein as the functional neuronal mZnR. Our work elucidates a fundamentally important role for synaptically released Zn2+acting as a neurotransmitter signal via activation of a mZnR to increase Cl−transport, thereby enhancing inhibitory tone in postsynaptic cells.
Gamma-Band Activation Predicts Both Associative Memory and Cortical Plasticity
Authors: Headley Drew B. , Weinberger Norman M.
Published: September 2011

Gamma-band oscillations are a ubiquitous phenomenon in the nervous system and have been implicated in multiple aspects of cognition. In particular, the strength of gamma oscillations at the time a stimulus is encoded predicts its subsequent retrieval, suggesting that gamma may reflect enhanced mnemonic processing. Likewise, activity in the gamma-band can modulate plasticityin vitro. However, it is unclear whether experience-dependent plasticityin vivois also related to gamma-band activation. The aim of the present study was to determine whether gamma activation in primary auditory cortex modulates both the associative memory for an auditory stimulus during classical conditioning and its accompanying specific receptive field plasticity. Rats received multiple daily sessions of single tone/shock trace and two-tone discrimination conditioning, during which local field potentials and multiunit discharges were recorded from chronically implanted electrodes. We found that the strength of tone-induced gamma predicted the acquisition of associative memory 24 h later and ceased to predict subsequent performance once asymptote was reached. Gamma activation also predicted receptive field plasticity that specifically enhanced representation of the signal tone. This concordance provides a long-sought link between gamma oscillations, cortical plasticity, and the formation of new memories.
Early Changes in Cerebellar Physiology Accompany Motor Dysfunction in the Polyglutamine Disease Spinocerebellar Ataxia Type 3
Authors: Shakkottai Vikram G. , do Carmo Costa Maria , Dell'Orco James M. , Sankaranarayanan Ananthakrishnan , Wulff Heike , Paulson Henry L.
Published: September 2011

The relationship between cerebellar dysfunction, motor symptoms, and neuronal loss in the inherited ataxias, including the polyglutamine disease spinocerebellar ataxia type 3 (SCA3), remains poorly understood. We demonstrate that before neurodegeneration, Purkinje neurons in a mouse model of SCA3 exhibit increased intrinsic excitability resulting in depolarization block and the loss of the ability to sustain spontaneous repetitive firing. These alterations in intrinsic firing are associated with increased inactivation of voltage-activated potassium currents. Administration of an activator of calcium-activated potassium channels, SKA-31, partially corrects abnormal Purkinje cell firing and improves motor function in SCA3 mice. Finally, expression of the disease protein, ataxin-3, in transfected cells increases the inactivation of Kv3.1 channels and shifts the activation of Kv1.2 channels to more depolarized potentials. Our results suggest that in SCA3, early Purkinje neuron dysfunction is associated with altered physiology of voltage-activated potassium channels. We further suggest that the observed changes in Purkinje neuron physiology contribute to disease pathogenesis, underlie at least some motor symptoms, and represent a promising therapeutic target in SCA3.
A Ca2+Threshold for Induction of Spike-Timing-Dependent Depression in the Mouse Striatum
Authors: Shindou Tomomi , Ochi-Shindou Mayumi , Wickens Jeffery R.
Published: September 2011

The striatum is the principal input nucleus of the basal ganglia, receiving glutamatergic afferents from the cerebral cortex. There is much interest in mechanisms of synaptic plasticity in the corticostriatal synapses. We used two-photon microscopy and whole-cell recording to measure changes in intracellular calcium concentration ([Ca2+]i) associated with spike-time-dependent plasticity in mouse striatum. Uncaging glutamate adjacent to a dendritic spine caused a postsynaptic potential at the soma and a rise in spine [Ca2+]i. Action potentials elicited at the soma raised both dendrite and spine [Ca2+]i. Pairing protocols in which glutamate uncaging preceded action potentials by 10 ms (pre-post protocol) produced supralinear increases in spine [Ca2+]icompared with the sum of increases seen with uncaging and action potentials alone, or timing protocols in which the uncaging followed the action potentials (post-pre protocols). The supralinear component of the increases in [Ca2+]iwere eliminated by the voltage-sensitive calcium channel blocker nimodipine. In the adjacent parent dendrites, the increases in [Ca2+]iwere neither supralinear nor sensitive to the relative pre-post timing. In parallel experiments, we investigated the effects of these pairing protocols on spike-timing-dependent synaptic plasticity. Long-term depression (t-LTD) of corticostriatal inputs was induced by pre-post but not post-pre protocols. Intracellular calcium chelators and calcium antagonists blocked pre-post t-LTD, confirming that elevated calcium entering via voltage-sensitive calcium channels is necessary for t-LTD. These findings confirm a spine [Ca2+]ithreshold for induction of t-LTD in the corticostriatal pathway, mediated by the supralinear increase in [Ca2+]iassociated with pre-post induction protocols.
Impact of clinical, hormonal, radiological, and immunohistochemical studies on the diagnosis of postmenopausal hyperandrogenism
Authors: Sarfati Julie , Bachelot Anne , Coussieu Christiane , Meduri Géri , Touraine Philippe
Published: September 2011

Objective

Evaluation of postmenopausal women with suspicion of androgen-secreting tumor.

Design and patients

We retrospectively studied 22 postmenopausal women referred to our center for suspicion of androgen-secreting tumor. All patients had clinical, biological, and morphological evaluation. In absence of adrenal tumors, ovarian surgery was most often proposed and immunohistochemistry (IHC) studies were performed.

Results

Ovarian tumors were detected by ultrasound and/or magnetic resonance imaging in eight patients. Two adrenal androgen-secreting tumors were diagnosed by an adrenal computed tomography (CT) scan. The clinical presentation of the women with or without tumors was similar. Nevertheless, women with tumor exhibited significantly higher testosterone levels and lower basal FSH and LH levels than the other women (2.6±2.7 vs 0.9±0.9 ng/ml,P<0.05; 26.5±22.9 vs 66.5±26.0 IU/l,P<0.01; and 12.0±8.6 vs 24.1±8.9 IU/l,P<0.05 respectively). Based on a likelihood ratio test, patients with a tumor had 8.4 and 10.8 times higher risk of having a testosterone level ≥1.4 ng/ml or an FSH level ≤35 IU/l. Finally, IHC analysis with an anti-P450c17α antibody allowed the identification of an elevated number of ovarian androgen-producing cells in five patients in whom no tumor was found.

Conclusions

Androgen-secreting tumors are clinically difficult to discriminate from other causes of postmenopausal hyperandrogenism. Testosterone and FSH were the two discriminative markers in a multivariate analysis. Ovarian and adrenal tumors were detected by imaging studies. However, ovarian non-tumoral causes of hyperandrogenism may be difficult to detect with conventional histology.
Differences in the participation of TGFB superfamily signalling pathways mediating porcine and murine cumulus cell expansion
Authors: Gilchrist Robert B , Ritter Lesley J
Published: September 2011

It is widely held that mammalian cumulus cell (CC) expansion requires oocyte-paracrine signalling, however in three of the four species studied to date, CC expansion occurs in the absence of the oocyte. This study was conducted to examine the paracrine and SMAD/MAPK intracellular signalling mechanism mediating porcine CC expansion, and to compare these to the mouse. Cumulus–oocyte complexes (COCs) and oocyte-free complexes (OOXs) from pigs and eCG-primed mice were treated in vitro with FSH and a broad range of TGFB superfamily antagonists. Expansion of porcine COCs and OOXs was unaffected by neutralisation of growth differentiation factor 9, TGFB, activin A, activin B and a broad spectrum bone morphogenetic protein antagonist. A SMAD-responsive luciferase reporter assay confirmed that porcine oocytes secreted factors that activate SMAD3 and SMAD1/5/8 in granulosa cells, but murine oocytes activated SMAD3 only. Treatment of COCs with a SMAD2/3 phosphorylation inhibitor (SB431542) partially inhibited porcine CC expansion and expression of TNFAIP6, but ablated murine CC expansion. SB431542 was equally effective at attenuating porcine CC expansion in the presence or absence of the oocyte. By contrast, a SMAD1/5/8 phosphorylation inhibitor (dorsomorphin) had no effect on porcine or murine CC function. Inhibition of ERK1/2 and p38 MAPK signalling pathways prevented porcine COC expansion and expression of most matrix genes examined. The activation of CC SMAD signalling by oocytes, and the requirement of SMAD2/3 signalling for expansion, is notably contrasted in pigs and mice. Nonetheless, porcine CC SMAD2/3 signalling is likely to be needed for optimal matrix formation, possibly by facilitating essential MAPK signals.
Polarized light acts as epigenetic factor in inhibition of inflammation; a genome wide expression analysis in recurrent respiratory diseases of children
Authors: Falus András , Fenyő Márta , Éder Katalin , Madarasi Anna
Published: September 2011

Whole-body polarized light therapy has been primarily investigated in various clinical observations and in a few in vitro model systems. Aims: In the present study, clinical and molecular effects of whole-body polarized light treatment on children suffering from recurrent respiratory infection were studied. Methods: Incidence and duration of respiratory symptoms as well as the length of appropriate antibiotic therapy have been measured. Simultaneously, genome-wide gene expression pattern was examined by whole genome cDNA microarray in peripheral lymphocytes of children. Results: Twenty of twenty five children showed a marked clinical improvement, while in five of twenty five had poor or no changes. Gene expression pattern of the peripheral lymphocytes of the patients was compared in favorable and poor responders. Lymphocytes of the children with a documented improved clinical response to polarized light therapy showed a decrease in the expression of chemokine genes, such as CXCL1, CXCL2, IL-8 and in that of the tumor necrosis alpha (TNFα) gene. On the contrary, a rapid elevation was found in the expression of gene encoding for CYP4F2, a leukotriene-B(4)-metabolizing enzyme. In children with poor clinical response to polarized light therapy, no similar changes were detected in the gene expression pattern of the lymphocytes. Conclusions: Improved clinical symptoms and modified gene expression profile of lymphocytes reveals anti-inflammatory effect upon whole body polarized light irradiation. Orv. Hetil., 2011, 152, 1492–1499.
Changes in the incidence of multiresistant pathogens and its consequences in intensive care unit
Authors: Szűcs Orsolya , Kristóf Katalin , Darvas Katalin , Csomós Ákos
Published: September 2011

Incidence of nosocomial infections and antibiotics resistance in intensive care units is increasing worldwide. Blood-stream infections of Gram-negative non-fermentive bacteria are associated with higher mortality. Aim and methods: The aim of this study was to compare the antibiotic sensitivity of nosocomial blood-stream infections between years 2008–2010. Results: There was no difference in the sensitivity of methycillin-resistant Staphylococcus aureus and extended-spectrum beta lactamase producing Klebsiella spp. and Escherichia coli infections between the two years examined. Antibiotic resistance of Acinetobacter baumannii and Pseudomonas infections showed a marked increase in 2010 when compared to that found in 2008: there was no multiresistant Acinetobacter infection in samples obtained in 2008, but all these infections were found to be sensitive only to colistin in samples investigated in 2010. Sensitivity of Pseudomonas infections to carbapenems and piperacillin/tazobactam decreased significantly during this time. In addition, the authors found that the mortality of multiresistant Gram-negative blood-stream infections was higher compared to that caused by non-multiresistant bacteria. Conclusions: These results emphasize the importance of infection control, adequate dosing and timing of antibiotics, and an appropriate number of nurses in intensive care unit. Orv. Hetil., 2011, 152, 1486–1491.
The use of MSR (Minimum Sample Richness) for sample assemblage comparisons
Authors: Travouillon Kenny J. , Escarguel Gilles , Legendre Serge , Archer Michael , Hand Suzanne J.
Published: September 2011

Minimum Sample Richness (MSR) is defined as the smallest number of taxa that must be recorded in a sample to achieve a given level of inter-assemblage classification accuracy. MSR is calculated from known or estimated richness and taxonomic similarity. Here we test MSR for strengths and weaknesses by using 167 published mammalian local faunas from the Paleogene and early Neogene of the Quercy and Limagne area (Massif Central, southwestern France), and then apply MSR to 84 Oligo-Miocene faunas from Riversleigh, northwestern Queensland, Australia. In many cases, MSR is able to detect the assemblages in the data set that are potentially too incomplete to be used in a similarity-based comparative taxonomic analysis. The results show that the use of MSR significantly improves the quality of the clustering of fossil assemblages. We conclude that this method can screen sample assemblages that are not representative of their underlying original living communities. Ultimately, it can be used to identify which assemblages require further sampling before being included in a comparative analysis.
Gizzard vs. teeth, it's a tie: food-processing efficiency in herbivorous birds and mammals and implications for dinosaur feeding strategies
Authors: Fritz Julia , Hummel Jürgen , Kienzle Ellen , Wings Oliver , Streich W. Jürgen , Clauss Marcus
Published: September 2011

Particle size reduction is a primary means of improving efficiency in herbivores. The mode of food particle size reduction is one of the main differences between herbivorous birds (gizzard) and mammals (teeth). For a quantitative comparison of the efficiency of food comminution, we investigated mean fecal particle sizes (MPS) in 14 herbivorous bird species and compared these with a data set of 111 non-ruminant herbivorous mammal species. In general MPS increased with body mass, but there was no significant difference between birds and mammals, suggesting a comparable efficiency of food processing by gizzards and chewing teeth. The results lead to the intriguing question of why gizzard systems have evolved comparatively rarely among amniote herbivores. Advantages linked to one of the two food comminution systems must, however, be sought in different effects other than size reduction itself. In paleoecological scenarios, the evolution of “dental batteries,” for example in ornithopod dinosaurs, should be considered an advantage compared to absence of mastication, but not compared to gizzard-based herbivory.
Evolution of dental wear and diet during the origin of whales
Authors: Thewissen J. G. M. , Sensor Jennifer D. , Clementz Mark T. , Bajpai Sunil
Published: September 2011

Dental morphology changes dramatically across the artiodactyl-cetacean transition, and it is generally assumed that this reflects the evolutionary change from herbivory and omnivory to carnivory. To test hypotheses regarding tooth function and diet, we studied size and position of wear facets on the lower molars and the stable isotopes of enamel samples. We found that nearly all investigated Eocene cetaceans had dental wear different from typical wear in ungulates and isotope values indicating that they hunted similar prey and processed it similarly. The only exception is the protocetid Babiacetus, which probably ate larger prey with harder skeletons. The closest relative of cetaceans, the raoellid artiodactyl Indohyus, had wear facets that resemble those of Eocene cetaceans more than they do facets of basal artiodactyls. This is in spite of Indohyus's tooth crown morphology, which is unlike that of cetaceans, and its herbivorous diet, as indicated by stable isotopes. This implies that the evolution of masticatory function preceded that of crown morphology and diet at the origin of cetaceans.
The effect of weathering on bird bone survivorship in modern and fossil saline-alkaline lake environments
Authors: Prassack Kari Alyssa
Published: September 2011

A modern Lesser Flamingo (Phoeniconaias minor) assemblage was collected along the shoreline of Lake Emakat, a saline-alkaline lake in northern Tanzania. Taphonomic analysis found the assemblage to be heavily weathered. This is likely due to the bone's heightened exposure to solar radiation and corrosive soil and water chemistries, as is expected to occur in such depositional environments.

Analysis found that deep, wide, longitudinal cracks penetrate the medullar cavities of both weathered and unweathered long bones. The cause and taphonomic consequence of these cracks are addressed here, using data from Lake Emakat and from controlled studies. Results support repeated (episodic) submersion, followed by drying, as the causal mechanism behind thesewet-drycracks. Mineral salt uptake by bone may explain the early appearance and prevalence of these cracks in saline-alkaline lake settings, as compared to other depositional settings.

The rate of weathering and incidence of wet-dry cracking varies significantly across limb elements. This difference correlates to element specific resistance properties to external loading forces. Heavy weathering weakens the structural integrity of bone and can accelerate its fragmentation. This can lead to bird bone loss in nearshore and ephemeral wetland settings, which may then affect resulting skeletal part, diversity, and richness profiles. Heavy weathering can therefore obscure important taphonomic and paleoecological information.

The weathering data collected here are then applied to a fossil bird assemblage from the FLK Complex, (late Pliocene), Olduvai Gorge, in Tanzania. Results provide evidence for the effect of weathering on paleoecological and behavioral interpretations. Weathering should be considered when analyzing fossil bird assemblages.
Shifting functional roles and the evolution of conifer pollen-producing and seed-producing cones
Authors: Leslie Andrew B.
Published: September 2011

Exploring patterns in the evolution of seed plant reproductive morphology within a functional context offers a framework in which to identify and evaluate factors that potentially drive reproductive evolution. Conifers are a particularly useful group for studies of this kind because they have a long geologic history and their reproductive organs are borne on separate structures with discrete functions. Multivariate analysis of morphological data collected from pollen-producing and seed-producing cones of Paleozoic, Mesozoic, and extant conifer species shows that seed cones underwent a significant expansion of morphological diversity that began during the Early-Middle Jurassic and has continued into the present day. In contrast, pollen cones show significantly lower levels of morphological diversity and exhibit similar basic morphologies throughout conifer evolutionary history. The increase in seed cone diversity through time is primarily the result of two novel structural and organizational features that evolved independently in different conifer families during the Mesozoic: robust, tightly packed cones in members of Araucariaceae, Cupressaceae sensu lato, and Pinaceae, and highly reduced, fleshy cones or solitary seeds in Podocarpaceae, Taxaceae, and some members of Cupressaceae sensu stricto. In extant conifers, these cone morphologies are associated with species that have strong interactions with vertebrate seed predators, seed dispersers, or a combination of both. This suggests that increases in the strength and complexity of biotic interactions in the Jurassic and Cretaceous were a primary driver of conifer reproductive evolution, and that patterns of character evolution relate to the increasing importance of cone tissue in seed protection and seed dispersal through time.
Shell geometry and habitat determination in extinct and extant turtles (Reptilia: Testudinata)
Authors: Benson Roger B. J. , Domokos Gábor , Várkonyi Péter L. , Reisz Robert R.
Published: September 2011

A variety of means, including forelimb proportions and shell bone histology have been used to infer the paleoecology of extinct turtles. However, the height-to-width ratio of the shell (as a one-parameter shell model) has been dismissed because of its unreliability, and more complex aspects of shell geometry have generally been overlooked. Here we use a more reliable, three-parameter geometric model of the shell outline in anterior view as a means to assess turtle paleoecology. The accuracy of predictions of extant turtle ecology based on our three-parameter shell model is comparable to that derived from forelimb proportions when distinguishing between three ecological classes (terrestrial, semiaquatic, and aquatic). Higher accuracy is obtained when distinguishing between two classes (terrestrial and non-terrestrial), because the contours of aquatic and semiaquatic turtles are often very similar. Our model classifiesProterochersis robusta, a stem turtle from the Late Triassic of Germany, as non-terrestrial, and likely semiaquatic. Our method, combined with inferences based on limb proportions, indicates a diverse range of ecotypes represented by Late Triassic stem turtles. This implies that the ecological diversification of stem-group turtles may have been rapid, or that a substantial period of currently cryptic diversification preceded the first fossil appearance of the turtle stem lineage during the Late Triassic.
Reliability of macrofossils in woodrat (Neotoma) middens for detecting low-density tree populations
Authors: Lesser Mark R. , Jackson Stephen T.
Published: September 2011

Macrofossils from woodrat (Neotoma) middens serve as an important proxy for reconstructing past vegetation in arid and semiarid regions of North America. The presence/absence of plant macrofossils in middens can provide valuable information on temporal and spatial patterns of plant migration and range boundaries. The primary aim of this study was to determine how local plant abundance, distance of plant populations from midden sites, and species population density on the landscape affect the probability of occurrence of macrofossils in middens. The study was designed with the primary intent of determining the reliability of middens in detecting scattered populations ofPinus ponderosa. We analyzed macrofossil assemblages from 42 modern woodrat middens from West Carrizo Canyon in southeastern Colorado, near the current eastern range margin ofPinus ponderosa. We compared midden contents with composition of the surrounding vegetation, measuring distance from the midden to the nearest individual of selected plant species, and the percent cover of each species within 30 m of the midden. We used this information to model the probability of species presence in a midden across a range of population densities on the landscape. Macrofossils ofJuniperusspp.,Quercus gambelii, andOpuntiaspp. were consistently found in middens regardless of their local abundance in vegetation, although populations occurred within 30 m of all middens.Pinus edulisandP. ponderosaoccurred in nearly all middens within 20–30 m of individual trees.P. ponderosawas rare in middens >20–30 m away from individual trees. Results of a simple simulation model suggest that middens become absolutely reliable indicators ofP. ponderosapresence on the landscape only when average tree density exceeds 50 stems ha−1. Woodrats reliably collected macrofossils ofPinus edulis, P. ponderosa, Juniperusspp.,Quercus gambelii, andOpuntiaspp. when populations of these taxa occur within 20–30 m of a midden site. Woodrats did not collectP. ponderosawhen the nearest individuals were more than 30 m away. Low-density populations of these and other species may be difficult to detect in fossil woodrat-midden series owing to reduced probability that individuals grow within foraging distance of the middens. Data from this and similar studies can be used to construct and parameterize a forward model of macrofossil representation in woodrat middens.
Unconfined shear strength of compacted unsaturated plastic soils
Authors: Marinho Fernando A. M. , Oliveira Orlando M.
Published: September 2011

A central goal in unsaturated soil mechanics research is to create a smooth transition between traditional soil mechanics approaches and an approach that is applicable to unsaturated soils. Undrained shear strength and the liquidity index of reconstituted or remoulded saturated soils are consistently correlated, which has been demonstrated by many studies. In the liquidity index range from 1 (at wl) to 0 (at wp), the shear strength ranges from approximately 2 kPa to 200 kPa. Similarly, for compacted soil, the shear strength at the plastic limit ranges from 150 kPa to 250 kPa. When compacted at their optimum water content, most soils have a suction that ranges from 20 kPa to 500 kPa; however, in the field, compacted materials are subjected to drying and wetting, which affect their initial suction and as a consequence their shear strength. Unconfined shear tests were performed on five compacted tropical soils and kaolin. Specimens were tested in the as-compacted condition, and also after undergoing drying or wetting. The test results and data from prior literature were examined, taking into account the roles of void ratio, suction, and relative water content. An interpretation of the phenomena that are involved in the development of the undrained shear strength of unsaturated soils in the contexts of soil water retention and Atterberg limits is presented, providing a practical view of the behaviour of compacted soil based on the concept of unsaturated soil. Finally, an empirical correlation is presented that relates the unsaturated state of compacted soils to the unconfined shear strength.
Flexible model structure for discrete-choice models
Authors: Ishaq Robert , Bekhor Shlomo , Shiftan Yoram
Published: September 2011

Discrete choice models are widely used for travel demand analyses, and several such models were developed based on random utility theory. The estimation process in such models generally uses the entire study population and the same model structure to estimate average parameter values, but this approach limits the possiblility that the model can fully explain the behaviour of different populations. A new approach, the flexible model structure (FMS), expands existing discrete choice models with the addition of two main components: the segmentation process and model structure search. The aim of the FMS process is to guide the progress of model estimation towards a more behaviourally realistic representation. The main contribution of this paper is to suggest and illustrate a framework that simultaneously searches for the best segmentation and the best model structure for each segment. This paper presents a numerical case study that illustrates the FMS concept. The results indicate that (a) the addition of the segmentation process acts to emphasise the heterogeneity that exists among segments and demonstrates the importance of segmentation by significantly improving the estimation results; and (b) the model structure can vary along segments.
Modelling of differential shrinkage of pavement slabs
Authors: Jeong Jin-Hoon , Lim Jin-Sun , Sun Ren-Juan , Zollinger Dan G.
Published: September 2011

Non-uniform moisture distribution through the depth of jointed concrete pavement causes greater shrinkage at the top of the slab than at the bottom. This kind of shrinkage behaviour induces warping and tensile stress in the top surface of the slab. The warping shape changes with concrete age. In this study, an instrumented concrete slab with vibrating wire strain gauges was constructed in the field to investigate strains in the slab. The coefficient of thermal expansion of concrete was tested in the laboratory, and the thermal and shrinkage strains were analysed from the testing data. Furthermore, shrinkage of the concrete slab was predicted via the ACI (American Concrete Institute) 209R-92 Code. Relevant correction factors for the ACI 209R-92 Code were determined by using simultaneous equations for different vertical positions. The shrinkage effects on the pavement slab were converted to thermal effects and the differential shrinkage–equivalent temperature difference (DSETD) was used to quantify the effects of shrinkage on the behaviour of the concrete pavement. A fairly good correlation occurred between the results obtained from the DSETD model and the field test.
The Influence of Early-Life Events on Human Capital, Health Status, and Labor Market Outcomes Over the Life Course
Authors: Johnson Rucker C , Schoeni Robert F
Published: September 2011

Using national data from the U.S., we find that poor health at birth and limited parental resources (including low income, lack of health insurance, and unwanted pregnancy) interfere with cognitive development and health capital in childhood, reduce educational attainment, and lead to worse labor market and health outcomes in adulthood. These effects are substantial and robust to the inclusion of sibling fixed effects and an extensive set of controls. The results reveal that low birth weight ages people in their 30s and 40s by 12 years, increases the probability of dropping out of high school by one-third, lowers labor force participation by 5 percentage points, and reduces labor market earnings by roughly 15 percent. While poor birth outcomes reduce human capital accumulation, they explain only 10 percent of the total effect of low birth weight on labor market earnings. Taken together, the evidence is consistent with a negative reinforcing intergenerational transmission of disadvantage within the family; parental economic status influences birth outcomes, birth outcomes have long reaching effects on health and economic status in adulthood, which in turn leads to poor birth outcomes for one’s own children.
Family and Community Influences on Health and Socioeconomic Status: Sibling Correlations Over the Life Course
Authors: Mazumder Bhashkar
Published: September 2011

This paper presents new estimates of sibling correlations in health and socioeconomic outcomes over the life course in the U.S. Sibling correlations provide an omnibus measure of the importance of all family and community influences. I find that sibling correlations in a range of health and socioeconomic outcomes start quite high at birth and remain high over the life course. The sibling correlation in birth weight is estimated to be 0.5. Sibling correlations in test scores during childhood are as high as 0.6. Sibling correlations in adult men’s wages are also around 0.5. Decompositions provide suggestive evidence on which pathways may account for the gradients in health and SES by family background. For example, sibling correlations in cognitive skills and non-cognitive skills during childhood are lower controlling for family income. Similarly, parent education levels can account for a sizable portion of the correlation in adult health status among brothers.
Role of Lipid Peroxidation and PPAR-δ in Amplifying Glucose-Stimulated Insulin Secretion
Authors: Cohen Guy , Riahi Yael , Shamni Ofer , Guichardant Michel , Chatgilialoglu Chryssostomos , Ferreri Carla , Kaiser Nurit , Sasson Shlomo
Published: September 2011

OBJECTIVE

Previous studies show that polyunsaturated fatty acids (PUFAs) increase the insulin secretory capacity of pancreatic β-cells. We aimed at identifying PUFA-derived mediators and their cellular targets that are involved in the amplification of insulin release from β-cells preexposed to high glucose levels.

RESEARCH DESIGN AND METHODS

The content of fatty acids in phospholipids of INS-1E β-cells was determined by lipidomics analysis. High-performance liquid chromatography was used to identify peroxidation products in β-cell cultures. Static and dynamic glucose-stimulated insulin secretion (GSIS) assays were performed on isolated rat islets and/or INS-1E cells. The function of peroxisome proliferator–activated receptor-δ (PPAR-δ) in regulating insulin secretion was investigated using pharmacological agents and gene expression manipulations.

RESULTS

High glucose activated cPLA2 and, subsequently, the hydrolysis of arachidonic and linoleic acid (AA and LA, respectively) from phospholipids in INS-1E cells. Glucose also increased the level of reactive oxygen species, which promoted the peroxidation of these PUFAs to generate 4-hydroxy-2E-nonenal (4-HNE). The latter mimicked the GSIS-amplifying effect of high glucose preexposure and of the PPAR-δ agonist GW501516 in INS-1E cells and isolated rat islets. These effects were blocked with GSK0660, a selective PPAR-δ antagonist, and the antioxidant N-acetylcysteine or by silencing PPAR-δ expression. High glucose, 4-HNE, and GW501516 also induced luciferase expression in a PPAR-δ–mediated transactivation assay. Cytotoxic effects of 4-HNE were observed only above the physiologically effective concentration range.

CONCLUSIONS

Elevated glucose levels augment the release of AA and LA from phospholipids and their peroxidation to 4-HNE in β-cells. This molecule is an endogenous ligand for PPAR-δ, which amplifies insulin secretion in β-cells.
A Randomized Controlled Trial Investigating the Effects of a Low–Glycemic Index Diet on Pregnancy Outcomes in Gestational Diabetes Mellitus
Authors: Louie Jimmy Chun Yu , Markovic Tania P. , Perera Nimalie , Foote Deborah , Petocz Peter , Ross Glynis P. , Brand-Miller Jennie C.
Published: September 2011

OBJECTIVE

The prevalence of gestational diabetes mellitus (GDM) is rising. There is little evidence to demonstrate the effectiveness of one dietary therapy over another. We aimed to investigate the effect of a low–glycemic index (LGI) versus a conventional high-fiber diet on pregnancy outcomes, neonatal anthropometry, and maternal metabolic profile in GDM.

RESEARCH DESIGN AND METHODS

Ninety-nine women (age 26–42 years; mean ± SD prepregnancy BMI 24 ± 5 kg/m2) diagnosed with GDM at 20–32 weeks’ gestation were randomized to follow either an LGI (n = 50; target glycemic index [GI] ~50) or a high-fiber moderate-GI diet (HF) (n = 49; target GI ~60). Dietary intake was assessed by 3-day food records. Pregnancy outcomes were collected from medical records.

RESULTS

The LGI group achieved a modestly lower GI than the HF group (mean ± SEM 47 ± 1 vs. 53 ± 1; P < 0.001). At birth, there was no significant difference in birth weight (LGI 3.3 ± 0.1 kg vs. HF 3.3 ± 0.1 kg; P = 0.619), birth weight centile (LGI 52.5 ± 4.3 vs. HF 52.2 ± 4.0; P = 0.969), prevalence of macrosomia (LGI 2.1% vs. HF 6.7%; P = 0.157), insulin treatment (LGI 53% vs. HF 65%; P = 0.251), or adverse pregnancy outcomes.

CONCLUSIONS

In intensively monitored women with GDM, an LGI diet and a conventional HF diet produce similar pregnancy outcomes.
Anthelmintic resistance in parasites of small ruminants: sheep versus goats
Authors: Várady M. , Papadopoulos E. , Dolinská M. , Königová A.
Published: September 2011

Anthelmintic resistance among parasites of sheep and goats has been known to occur for at least four decades. Both species of host have similar genera of nematodes, but the nematodes in goat herds usually develop anthelmintic resistance more rapidly. In vitro tests show higher ED50 values in goats than in flocks of sheep. Sheep and goats differ in many ways; for example, goats have a higher metabolic rate and require higher dose rates for drugs. The immune system of goats is also different. Additionally, these animals are reared under different management systems, i.e. sheep graze pastures and goats browse bushes, and lambing/kidding periods are different. Most anthelmintics used in goats have not been licensed for this animal species, and correct dose rates have rarely been experimentally determined. Possible explanations for such differences are discussed.
Fox tapeworm (Echinococcus multilocularis) in Slovakia — summarizing the long-term monitoring
Authors: Miterpáková M. , Dubinský P.
Published: September 2011

Detailed epidemiological survey on distribution of fox tapeworm Echinococcus multilocularis was carried out in the territory of Slovakia between 2000 and 2010. A total of 4 761 red foxes from all districts of Slovakia were investigated using modified sedimentation and counting method. E. multilocularis was found in small intestines of 1 441 animals that represent an overall prevalence of 30.3 %. The number of tapeworms found in individual foxes varied between 1 and 245 000 specimens with mean worm burden of 1 777. The results of decennial epizootological research confirmed the existence of highly endemic localities with E. multilocularis occurrence in northern regions of Slovakia. Till today, 16 human cases of alveolar echinococcosis were registered whereas 14 of them were diagnosed in patients living in endemic localities.
A new species of Dadayius Fukui, 1929 (Digenea: Cladorchiidae), parasite of Symphysodon aequifasciatus Pellegrin, 1904 (Perciformes: Cichlidae) from the Purus River, Amazon, Brazil
Authors: Lopes L. , Karling L. , Takemoto R. , Rossoni F. , Ferreira E. , Pavanelli G.
Published: September 2011

The present paper describes a new species of Dadayius Fukui, 1929 (Trematoda, Digenea), parasite of Symphysodon aequifasciatus Pellegrin, 1904, a freshwater fish. The fish were collected from the Purus River, Amazonas State, Brazil. This new species has a long body and, different from other species of the genus, an arch-shaped ovary and a sinuous oesophagus with an ovoid bulb. This is the first record of Dadayius in cichlid fish; to date Dadayius has only been found parasitizing characid fish.
Specificity of the number of nouns in Czech and its annotation in Prague Dependency Treebank
Authors: Ševčíková Magda , Panevová Jarmila , Smejkalová Lenka
Published: September 2011

Specificity of the number of nouns in Czech and its annotation in Prague Dependency Treebank

The paper focuses on the way how the grammatical category of number of nouns will be annotated in the forthcoming version of Prague Dependency Treebank (PDT 3.0), concentrating on the peculiarities beyond the regular opposition of singular and plural. A new semantic feature closely related to the category of number (so-called pair/group meaning) was introduced. Nouns such as ruce ‘hands’ or klíče ‘keys’ refer with their plural forms to a pair or to a typical group even more often than to a larger amount of single entities. Since pairs or groups can be referred to with most Czech concrete nouns, the pair/group meaning is considered as a grammaticalized meaning of nouns in Czech. In the present paper, manual annotation of the pair/group meaning is described, which was carried out on the data of Prague Dependency Treebank. A comparison with a sample annotation of data from Prague Dependency Treebank of Spoken Czech has demonstrated that the pair/group meaning is both more frequent and more easily distinguishable in the spoken than in the written data.
Calculating the main and leakage inductance matrix of the 3-column 15-winding autotransformer
Authors: Mazur Damian , Gołębiowski Marek
Published: September 2011

Calculating the main and leakage inductance matrix of the 3-column 15-winding autotransformer

The aim of this paper is presentation and comparison of calculation methods of the inductance matrix of a 3-column multi-winding autotransformer. Main and leakage autotransformer inductance was obtained using finite elements method. Static calculations were made at the current supply for 2D and 3D models, and mono-harmonic calculations were made at the voltage supply. In the mono-harmonic calculations the eddy current losses were taken into account, this made it possible to study relationship between the autotransformer parameters and the frequency. Calculations were made using Ansys and the authors' own programs in Matlab.
Measurement and calculation of 3-column 15-winding autotransformer
Authors: Mazur Damian , Gołębiowski Marek
Published: September 2011

Measurement and calculation of 3-column 15-winding autotransformer

The 15-winding and 3-column autotransformer supplying an 18-pulse rectifier circuit was developed. Presented methods can be used also for the autotransformers of other topologies supplying different kinds of converters. Presented methods make it possible to exactly calculate main and leakage inductances of the multi-winding autotransformer. The presented analysis of the eigenvalues and eigenvectors of the inductance matrix makes it possible to identify the influence nature of individual modes on the inductance matrix, and to compare the calculation results obtained using the presented methods. Frequency dependence of autotransformer parameters was shown. Also modes of the impedance matrix of the multi-winding autotransformer was investigated, this made it possible to identify the influence nature of individual modes on the inductance matrix. Using presented methods one can exactly calculate main and leakage inductances of the autotransformer. Thanks to this, one can design in optimal way autotransformers for supplying, for example, rectifier circuits, THD coefficients. The results of the measurements and simulations were also shortly presented at the end of the article.
Selection of control parameters in a control system with a DC electric series motor using evolutionary algorithm
Authors: Hudy Wiktor , Jaracz Kazimierz
Published: September 2011

Selection of control parameters in a control system with a DC electric series motor using evolutionary algorithm

This paper presents a method of selection of regulator parameters in a control system using evolutionary algorithm. The control system has one PI controller and one hysteresis controller. The value of the proportional band and the value of the Integral time were defined by evolutionary algorithms. The object of control was a Brown Boveri GS10A motor. The task functions were the step change of rotational speed and step change of the motor's torque. The control system with the parameters selected by means of the evolutionary method was verified by using MATLAB/Simulink environment.
On-line losses minimization of induction motor vector control
Authors: Rouabah Z. , Abdelhadi B. , Anayi F. , Zidani F.
Published: September 2011

On-line losses minimization of induction motor vector control

Conventional field-orientated Induction motor drives operate at rated flux even at low load. To improve the efficiency of the existing motor it is important to regulate the flux of the motor in the desired operating range. In this paper a loss model controller (LMC) based on the real coded genetic algorithm is proposed, it has the straightforward goal of maximizing the efficiency for each given load torque. In order to give more accuracy to the motor model and the LMC a series model of the motor which consider the iron losses as a resistance connected in series with the mutual inductance is considered. Digital computer simulation demonstrates the effectiveness of the proposed algorithm and also simulation results have confirmed that this algorithm yields the optimal efficiency.
Shock safety modelling of indirect contact with low-voltage electric devices
Authors: Korniluk Włodzimierz , Sajewicz Dariusz
Published: September 2011

Shock safety modelling of indirect contact with low-voltage electric devices

The article presents a shock safety model of an indirect contact with a low-voltage electric device. This model was used for computations and analyses concerning the following: the probabilities of appearance of the particular shock protection unreliability states, electric shock states (ventricular fibrillation), contributions of the unreliability of different shock protection elements to the probability of occurrence of these states, as well as the risk of electric shock (and the shock safety), and contributions of the intensity of occurrence of damages to different shock protection elements to this risk. An example of a possibility to reduce the risk of an electric shock through changing the intensity of occurrence of damages to the selected protection elements was provided.