bluuebunny/crossref_metadata_2025_split huggingface dataset:
New approach in studies of microalgal cell lysis
Authors: Berden-Zrimec Maja , Logar Jasmina , Zrimec Alexis , Drinovec Luka , Franko Mladen , Malej Alenka 
Published: June 2009

AbstractA new approach to the studies of the microalgal cell lysis by utilizing a combination of two complementary methods is presented. Delayed fluorescence (DF) is a measure of the living algal biomass, detecting only cells with active photosynthesis. Thermal lens spectrometry (TLS) detects the total pigment amount released from lysed cells. Both methods select for photosynthetic organisms, reducing possible background from other sources (e.g. heterotrophic bacteria, zooplankton, and abiotic substances). The DF/TLS method was tested with a laboratory Skeletonema costatum culture exposed to a geometric dilution series of the lysing factor poly- APS. The exposure resulted in similar EC50 values for DF intensity, TLS and dissolved esterase activity of 0.8±0.2, 1.77±0.35, and 1.25±0.1 mg poly-APS l−1, respectively. The combined DF/TLS method enabled a rapid evaluation of the living vs. dead cells without any sample pretreatment or manipulation.
The transcriptional regulation of Podocin (NPHS2) by Lmx1b and a promoter single nucleotide polymorphism
Authors: Harendza Sigrid , Stahl Rolf , Schneider André 
Published: June 2009

AbstractPodocin (NPHS2) is a component of the glomerular slit membrane with major regulatory functions in the renal permeability of proteins. A loss of podocin and a decrease in its resynthesis can influence the outcome of renal diseases with nephrotic syndrome, such as minimal change glomerulonephritis, focal segmental glomerulosclerosis (FSGS) and membranous nephropathy. The transcriptional regulation of podocin may play a major role in these processes. We defined the transcriptional regulation of the human podocin gene and the influence of single nucleotide polymorphisms (SNPs) within its promoter region in the podocytes using reporter gene constructs and gel shift analysis. In addition, we took genomic DNA from healthy Caucasian blood donors and from biopsies of kidneys with defined renal diseases and screened it for podocin promoter SNPs. Our data shows that the transcription of podocin is mainly regulated by the transcription factor Lmx1b, which binds to a FLAT-F element and displays enhancer function. With the SNP variant −116T, there was a significant reduction in luciferase activity, and nuclear protein binding was observed, while the SNP −670C/T did not display functionality. The allelic distribution of −116C/T in patients with kidney diseases leading to nephrotic syndrome was not significantly different from that in the control group. Our data indicates that among other factors, podocin is specifically regulated by the transcription factor Lmx1b and by the functional polymorphism -116C/T. However, there is no association between −116C/T and susceptibility to minimal change glomerulonephritis, focal segmental glomerulosclerosis or membranous nephropathy.
Overexpression of human osteopontin increases cell proliferation and migration in human embryo kidney-293 cells
Authors: Liu Ya-Jun , Zhang Dao-Qiang , Sui Xiu-Mei , Tian Wei 
Published: June 2009

AbstractMalignant tumors are characterized by dysregulated cell growth and the metastasis of secondary tumors. Numerous studies have documented that osteopontin (OPN) plays a key role in regulating tumor progression and metastasis. Here, we show that the overexpression of OPN in human embryo kidney-293 cells significantly increases both the level of cell proliferation, by provoking the G1/S transition, and the level of cell migration in vitro. These findings suggest that augmented OPN contributes to cell growth and motility. Inhibiting OPN or the pathway it stimulates may therefore represent a novel approach for the treatment of primary tumors and associated metastases.
Molecular characterization of the niaD and pyrG genes from Penicillium camemberti, and their use as transformation markers
Authors: Navarrete Katherinne , Roa Amanda , Vaca Inmaculada , Espinosa Yeison , Navarro Claudio , Chávez Renato 
Published: June 2009

AbstractGenetic manipulation of the filamentous fungus Penicillium camemberti has been limited by a lack of suitable genetics tools for this fungus. In particular, there is no available homologous transformation system. In this study, the nitrate reductase (niaD) and orotidine-5′-monophosphate decarboxylase (pyrG) genes from Penicillium camemberti were characterized, and their suitability as metabolic molecular markers for transformation was evaluated. The genes were amplified using PCR-related techniques, and sequenced. The niaD gene is flanked by the nitrite reductase (niiA) gene in a divergent arrangement, being part of the putative nitrate assimilation cluster in P. camemberti. pyrG presents several polymorphisms compared with a previously sequenced pyrG gene from another P. camemberti strain, but almost all are silent mutations. Southern blot assays indicate that one copy of each gene is present in P. camemberti. Northern blot assays showed that the pyrG gene is expressed in minimal and rich media, and the niaD gene is expressed in nitrate, but not in reduced nitrogen sources. The functionality of the two genes as transformation markers was established by transforming A. nidulans pyrG- and niaD-deficient strains. Higher transformation efficiencies were obtained with a pyrG-containing plasmid. This is the first study yielding a molecular and functional characterization of P. camemberti genes that would be useful as molecular markers for transformation, opening the way for the future development of a non-antibiotic genetic transformation system for this fungus.
Upwelling characteristics in the Puck Bay (the Baltic Sea)
Authors: Nowacki Jacek , Matciak Maciej , Szymelfenig Maria , Kowalewski Marek 
Published: June 2009

Abstract
The spatial distributions of basic water parameters in the Puck Bay, a small semi-closed water body located on the southern coast of the Baltic Sea, were often typical of upwelling phenomenon. In such situations, like those observed in July of 1999, temperature decreased locally and water transparency increased locally. The present study analyzed conditions under which upwelling occurred using maps of horizontal currents at different depths, which were obtained from an operational hydrodynamic model. With north, northwest winds the upwelling in Puck Bay looked like the shallow-water upwelling arising as a direct dynamic response of the water body to the wind direction, without a distinct effect of the Coriolis force. However, upwelling water circulation during other wind directions, i.e. west and northeast winds, did not match this simple scheme and was affected by coastline configuration. The results of many years' measurements pointed at an important role of upwelling in hydrological regime formation in the shallow parts of the Puck Bay.
Centric diatoms (Coscinodiscophyceae) of fresh and brackish water bodies of the southern part of the Russian Far East
Authors: Medvedeva Lubov , Nikulina Tatyana , Genkal Sergey 
Published: June 2009

Abstract
Anotated list of centric diatoms (Coscinodiscophyceae) of fresh and brackish water bodies of the southern Russian Far East, based on the authors' data, supplemented by the published literature, is given. It includes 143 algae species (including varieties and forms - 159 taxa) representing 38 genera, 22 families and 14 orders.
The food preferences of three-spined stickleback, Gasterosteus aculeatus L., downstream from a dam reservoir
Authors: Dukowska Małgorzata , Grzybkowska Maria , Marszał Lidia , Zięba Grzegorz 
Published: June 2009

Abstract
Submersed plants appeared in the impounded section of the Warta River as a consequence of low discharge in summer and were colonized by epiphytic fauna dominated by Hydra sp., Simuliidae, and Chironomidae. The three-spined stickleback consumed it voraciously, and their diet composition closely reflected the available food resources. In May their alimentary tracts were filled with Cladocera drifting from the reservoir, and then by the dominant taxa associated with macrophytes, especially chironomid periphyton scrapers. A comparison of dipteran head capsule width in the food resources and in the alimentary tract proved the three-spined stickleback preference for the largest larvae (optimal foraging strategy).
Cytogenetic characteristics of species of the Chironomus genus (Diptera, Chironomidae) from Lake Łuknajno Biosphere Reserve (northwest Poland)
Authors: Jabłońska-Barna Izabela , Michailova Paraskeva 
Published: June 2009

Abstract
The cytotaxonomic characteristics of two species of the Chironomus genus from Lake Łuknajno (northwest Poland) were determined: Chironomus nuditarsis Strenzke, 1959 with the chromosome arm combinations of AB, CD, EF, and G (the "thummi" cytocomplex), and Camptochironomus tentans (Fabricius, 1805) with the chromosome arm combinations of AB, CF, DE, and G. A heterozygous inversion in arm F of the Chironomus nuditarsis chromosomes was detected. The polymorphism of Camptochironomus tentans as a homozygous inversion in arms A and E and a heterozygous inversion in arm F were revealed.
Chironomidae (Diptera) community response to improved oxygen conditions in a naturally recovering lake (Łękuk Wielki, northeast Poland)
Authors: Koszałka Jacek 
Published: June 2009

Abstract
A Study of the chironomid community was undertaken in Lake Łękuk Wielki during the 1997-1999 period. Twenty six taxon belonging to the subfamilies Tanypodinae and Chironomini were identified. Taxonomic diversity decreased with increasing depth in the lake, but the occurrence of Chironomidae larvae was noted even in the deepest part of the lake. Chironomidae clearly indicated that Lake Łękuk Wielki is recovering.
Composition and origin of amber ice and its influence on the behaviour of cold glaciers in the McMurdo Dry Valleys, Antarctica
Authors: Mager Sarah , Fitzsimons Sean , Frew Russell , Samyn Denis , Lorrain Reginald 
Published: June 2009

AbstractThis paper examines the basal ice sequence of Rhone Glacier, a cold-based glacier in the McMurdo Dry Valleys, Antarctica, using isotopic and solute chemistry data. Three different ice facies are identified: englacial, amber and stratified. The englacial facies is clean, bubbly ice of meteoric origin and is underlain by an amber facies. Amber ice is a characteristic of cold alpine glaciers in the McMurdo Dry Valleys and is distinctive for its high solute concentrations and much higher strain rates compared with the overlying englacial ice and the underlying stratified ice. Analysis of the stratified facies reveals an isotopic signature indicative of melt then refreeze processes and it is most likely associated with apron entrainment at the margin. By contrast, the amber facies has a co-isotopic slope of 8 and plots on a meteoric waterline. The inclusion of impurities in the amber ice reveals prolonged contact with the bed, and its depleted isotopic signature is consistent with ice formed during a cooler period. Comparison of the basal sequence of Rhone Glacier with other cold-based glaciers in the McMurdo Dry Valleys reveals strong similarities between valley-side glaciers (e.g. Meserve and Rhone Glaciers), whereas valley-floor glacier basal sequences (e.g. Suess Glacier) are characterized by structurally complex amalgamations of ice and debris.
Basal conditions for Pine Island and Thwaites Glaciers, West Antarctica, determined using satellite and airborne data
Authors: Joughin Ian , Tulaczyk Slawek , Bamber Jonathan L. , Blankenship Don , Holt John W. , Scambos Ted , Vaughan David G. 
Published: June 2009

AbstractWe use models constrained by remotely sensed data from Pine Island and Thwaites Glaciers, West Antarctica, to infer basal properties that are difficult to observe directly. The results indicate strong basal melting in areas upstream of the grounding lines of both glaciers, where the ice flow is fast and the basal shear stress is large. Farther inland, we find that both glaciers have ‘mixed’ bed conditions, with extensive areas of both bedrock and weak till. In particular, there are weak areas along much of Pine Island Glacier’s main trunk that could prove unstable if it retreats past the band of strong bed just above its current grounding line. In agreement with earlier studies, our forward ice-stream model shows a strong sensitivity to small perturbations in the grounding line position. These results also reveal a large sensitivity to the assumed bed (sliding or deforming) model, with non-linear sliding laws producing substantially greater dynamic response than earlier simulations that assume a linear-viscous till rheology. Finally, comparison indicates that our results using a plastic bed are compatible with the limited observational constraints and theoretical work that suggests an upper bound exists on maximum basal shear stress.
Measured shear rates in large dry and wet snow avalanches
Authors: Kern Martin , Bartelt Perry , Sovilla Betty , Buser Othmar 
Published: June 2009

AbstractWe present estimates of internal shear rates of real-scale avalanches that are based on velocity measurements. Optical velocity sensors installed on the instrument pylon at the Swiss Vallée de la Sionne test site are used to measure flow velocities at different flow heights of three large dry and wet snow avalanches. Possible sources of error in the correlation analysis of the time-lagged reflectivity signals measured by optical sensors are identified for real-size avalanches. These include spurious velocities due to noise and elongated peaks. An appropriate choice of the correlation length is essential for obtaining good velocity estimates. Placing restrictions on the maximum possible accelerations in the flow improves the analysis of the measured data. Coherent signals are found only in the dense flowing cores. We observe the evolution of shear rates at different depths between the front and tail of the flowing avalanche. At the front, large shear rates are found throughout the depth; at the tail, plug flows overriding highly sheared layers near the bottom of the flow are observed. The measured velocities change strongly with height above the ground and fluctuations around the measured mean velocity can be identified. We find that the dense flows are laminar, undergoing a transition from supercritical to subcritical flow behaviour from the head to the tail. Furthermore, we provide real-scale experimental evidence that the mean shear rate and the magnitude of velocity fluctuations increase with the mean discharge.
Age–depth correlation, grain growth and dislocation-density evolution, for three ice cores
Authors: Morland L.W. 
Published: June 2009

AbstractTwo previous theoretical analyses of data from the GRIP, Vostok and Byrd ice cores, presenting age–depth correlations, grain growth and dislocation-density evolution, are re-examined. It is found that the age–depth correlations are inconsistent with the idealized flow with unchanging history adopted, but that good correlations can be obtained by relaxing those restrictions. A modified grain-growth relation is proposed, consistent with the distinct growth profiles of the Vostok and other two cores, which can be solved simultaneously with the given dislocation-density evolution equation. These are solved for all three cores with the given parameters, and the depth profiles of grain diameter and dislocation density at the present time are determined with the new age–depth correlation and with that shown empirically in the papers. The varying flow history influences the age–depth correlation, and hence the depth profiles, which is important both for the interpretation of core data, and for the determination of constitutive variables at each depth at the present time.
Estimation of glacier runoff and future trends in the Yangtze River source region, China
Authors: Shiyin Liu , Yong Zhang , Yingsong Zhang , Yongjian Ding 
Published: June 2009

AbstractGlacier runoff from the Yangtze River source region (YRSR), China, is estimated for the period 1961–2000 using a degree-day approach. In the investigation area, glacier runoff accounts for 11.0% of the total river runoff during the period 1961–2000. In the 1990s its contribution to river runoff rises to 17.0%. Due to the current rate of glacier decline, the impact of glacier runoff on river runoff has recently increased in the source region. Based on two different climate-change scenarios derived from ECHAM5/MPI-OM, future glacier runoff is assessed for the period 2001–50. In all climate-change scenarios, annual glacier runoff shows a significant increase due to intensified ice melting. There is an increase in glacier runoff during spring and early summer, yet a significant decrease in late summer. This study highlights the current and future impact of glacier runoff on river runoff in the YRSR.
A cut-and-closure origin for englacial conduits in uncrevassed regions of polythermal glaciers
Authors: Gulley J.D. , Benn D.I. , Müller D. , Luckman A. 
Published: June 2009

AbstractOn uncrevassed regions of polythermal glaciers, englacial conduits can form by incision of supraglacial stream channels followed by roof closure. The origin and evolution of examples in Longyearbreen, Svalbard, and Khumbu Glacier, Nepal, were determined by speleological survey. The development of perennial incised channels requires that incision is significantly faster than glacier surface ablation, and thus will be favoured by high meltwater discharges in combination with cool climatic conditions or thick debris cover. Incised canyons can become blocked by drifted winter snow, refrozen meltwater, ice rafting from non-local sources (allochthonous breccias) and roof collapses (autochthonous breccias). Conduit closure can also occur in response to ice creep, particularly at depth. Following isolation from the surface, englacial conduits continue to evolve by vadose incision down to local base level. In the case of Longyearbreen, incision allowed the channel to reach the glacier bed, but on Khumbu Glacier deep incision is prevented because an effectively impermeable terminal moraine provides a high base level for the glacier drainage system. During our period of observations, deeper parts of the Longyearbreen conduit became blocked by a combination of ice accumulation and creep, causing the stream course to be re-routed to higher levels. On that glacier, incision, blockage and upward re-routing are cyclic. We conclude that ‘cut and closure’ is the dominant mechanism of englacial conduit formation on uncrevassed regions of polythermal glaciers.
Mass balance, flow and subglacial processes of a modelled Younger Dryas ice cap in Scotland
Authors: Golledge Nicholas R. , Hubbard Alun L. , Sugden David E. 
Published: June 2009

AbstractWe use an empirically validated high-resolution three-dimensional ice-sheet model to investigate the mass-balance regime, flow mechanisms and subglacial characteristics of a simulated Younger Dryas Stadial ice cap in Scotland, and compare the resulting model forecasts with geological evidence. Input data for the model are basal topography, a temperature forcing derived from GRIP δ18O fluctuations and a precipitation distribution interpolated from modern data. The model employs a positive-degree-day scheme to calculate net mass balance within a domain of 112500 km2, which, under the imposed climate, gives rise to an elongate ice cap along the axis of the western Scottish Highlands. At its maximum, the ice cap is dynamically and thermally zoned, reflecting topographic and climatic controls, respectively. In order to link these palaeoglaciological conditions to geological interpretations, we calculate the relative balance between sliding and creep within the simulated ice cap, forecast areas of the ice cap with the greatest capacity for basal erosion and predict the likely pattern of subglacial drainage. We conclude that ice flow in central areas of the ice cap is largely due to internal deformation, and is associated with geological evidence of landscape preservation. Conversely, the distribution of streamlined landforms is linked to faster-flowing ice whose velocity is predominantly the result of basal sliding. The geometry of the main ice mass focuses subglacial erosion in the mid-sections of topographic troughs, and produces glaciohydraulic gradients that favour subglacial drainage through low-order arterial routes.
Comparison of density cutters for snow profile observations
Authors: Conger Steven M. , McClung David M. 
Published: June 2009

AbstractAn investigation was made to estimate the variance, measurement errors and sampling error in currently accepted practices for manual snow density measurement carried out as part of snow profile observations using the available variety of density cutters. A field experiment in dry snow conditions was conducted using a randomized block design to account for layer spatial variability. Cutter types included a 500 cm3 aluminium tube, 200 and 100 cm3 stainless-steel box types, 200 cm3 stainless-steel wedge types and a 100 cm3 stainless-steel tube. Without accounting for variation due to weighing devices, the range of values for ‘accepted practice’ determined in this study included variation within individual cutters of 0.8–6.2%, variation between cutters of 3–12%, variation between cutter means and layer means of 2–7%, and under-sampling errors of 0–2%. The results of a statistical analysis suggest that snow density measurements taken using various density cutters are significantly different from each other. Without adjustment for under-sampling, and given that the mean of all measurements is the accepted true value of the layer density, variation exclusively between cutter types provides ‘accepted practice’ measurements that are within 11% of the true density.
Ambivalence: The Divided Self in Sylvia Plath's Poetry
Authors: Sharif Mohd Yasin 
Published: June 2009

Ambivalence, mixed good and bad feelings about particular entity, individual or circumstance, became a ruling passion in Sylvia Plath's life. These ambivalence and breakdown are closely dealt with in her poems. Confessional poets usually reveal their own personal experiences without straining excruciating sentiment. Sylvia Plath, one of the 1960s most influential confessional poets used the same resentment and anguish that developed from her personal grief as the subject of many of her poems. SP is well known among the celebrities for her ambivalence schizophrenic, schizoid and paranoid nature. As an obsessive-compulsive neurotic, ambivalence dominated both her works as well as her life. This ambivalent personality of SP made her and her works obscure and bizarre to the readers. Many of her poems bear the evidence of narcissism, self-hatred, deep attachment and simultaneously deep hatred towards her dear and near ones. The present study is an endeavor to interpret this complex ambivalent personality of SP in light of her poems, her journals and her letters where she clearly confesses all her neurotic obsessed activities directly, honestly and sincerely without any hesitation. The study will also dug out the true logical reasons that lead to the suicide of a blooming star in her make up. doi: 10.3329/iiucs.v3i0.2628 IIUC STUDIES Vol. - 3, December 2006 (p 7-18)
The Woman Question in the novels by the Bronte Sisters
Authors: Anis Rehnuma Bint 
Published: June 2009

The Victorian period lasted more than half a century. During this time England changed radically in almost all respects. One of these was the rising consciousness of women about their rights and potentials. Soon, the social awareness was transmitted to literature. In retrospect we find that many women writers emerged at this critical juncture in history when women were pleading to be given voice, to achieve their rights and to be given an opportunity to come out of the shells of quiet submission enforced upon them and achieve something of their own. Three sisters living deep in the Yorkshire moors surprised the world by taking part in this ongoing struggle. This article attempts to evaluate their contributions towards achieving women's rights in English history. doi: 10.3329/iiucs.v3i0.2629 IIUC STUDIES Vol. - 3, December 2006 (p 19-30)