bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulating Conscious Movement Intention by Noninvasive Brain Stimulation and the Underlying Neural Mechanisms
Authors: Douglas Zachary H. , Maniscalco Brian , Hallett Mark , Wassermann Eric M. , He Biyu J.
Published: May 2015

Conscious intention is a fundamental aspect of the human experience. Despite long-standing interest in the basis and implications of intention, its underlying neurobiological mechanisms remain poorly understood. Using high-definition transcranial DC stimulation (tDCS), we observed that enhancing spontaneous neuronal excitability in both the angular gyrus and the primary motor cortex caused the reported time of conscious movement intention to be ∼60–70 ms earlier. Slow brain waves recorded ∼2–3 s before movement onset, as well as hundreds of milliseconds after movement onset, independently correlated with the modulation of conscious intention by brain stimulation. These brain activities together accounted for 81% of interindividual variability in the modulation of movement intention by brain stimulation. A computational model using coupled leaky integrator units with biophysically plausible assumptions about the effect of tDCS captured the effects of stimulation on both neural activity and behavior. These results reveal a temporally extended brain process underlying conscious movement intention that spans seconds around movement commencement.
Evidence for Neural Computations of Temporal Coherence in an Auditory Scene and Their Enhancement during Active Listening
Authors: O'Sullivan James A. , Shamma Shihab A. , Lalor Edmund C.
Published: May 2015

The human brain has evolved to operate effectively in highly complex acoustic environments, segregating multiple sound sources into perceptually distinct auditory objects. A recent theory seeks to explain this ability by arguing that stream segregation occurs primarily due to the temporal coherence of the neural populations that encode the various features of an individual acoustic source. This theory has received support from both psychoacoustic and functional magnetic resonance imaging (fMRI) studies that use stimuli which model complex acoustic environments. Termed stochastic figure–ground (SFG) stimuli, they are composed of a “figure” and background that overlap in spectrotemporal space, such that the only way to segregate the figure is by computing the coherence of its frequency components over time. Here, we extend these psychoacoustic and fMRI findings by using the greater temporal resolution of electroencephalography to investigate the neural computation of temporal coherence. We present subjects with modified SFG stimuli wherein the temporal coherence of the figure is modulated stochastically over time, which allows us to use linear regression methods to extract a signature of the neural processing of this temporal coherence. We do this under both active and passive listening conditions. Our findings show an early effect of coherence during passive listening, lasting from ∼115 to 185 ms post-stimulus. When subjects are actively listening to the stimuli, these responses are larger and last longer, up to ∼265 ms. These findings provide evidence for early and preattentive neural computations of temporal coherence that are enhanced by active analysis of an auditory scene.
Layer 4 Pyramidal Neurons Exhibit Robust Dendritic Spine PlasticityIn Vivoafter Input Deprivation
Authors: Miquelajauregui Amaya , Kribakaran Sahana , Mostany Ricardo , Badaloni Aurora , Consalez G. Giacomo , Portera-Cailliau Carlos
Published: May 2015

Pyramidal neurons in layers 2/3 and 5 of primary somatosensory cortex (S1) exhibit somewhat modest synaptic plasticity after whisker input deprivation. Whether neurons involved at earlier steps of sensory processing show more or less plasticity has not yet been examined. Here, we used longitudinalin vivotwo-photon microscopy to investigate dendritic spine dynamics in apical tufts of GFP-expressing layer 4 (L4) pyramidal neurons of the vibrissal (barrel) S1 after unilateral whisker trimming. First, we characterize the molecular, anatomical, and electrophysiological properties of identified L4 neurons in Ebf2-Cre transgenic mice. Next, we show that input deprivation results in a substantial (∼50%) increase in the rate of dendritic spine loss, acutely (4–8 d) after whisker trimming. This robust synaptic plasticity in L4 suggests that primary thalamic recipient pyramidal neurons in S1 may be particularly sensitive to changes in sensory experience. Ebf2-Cre mice thus provide a useful tool for future assessment of initial steps of sensory processing in S1.
Unilateral Prefrontal Lesions Impair Memory-Guided Comparisons of Contralateral Visual Motion
Authors: Pasternak Tatiana , Lui Leo L. , Spinelli Philip M.
Published: May 2015

The contribution of the lateral prefrontal cortex (LPFC) to working memory is the topic of active debate. On the one hand, it has been argued that the persistent delay activity in LPFC recorded during some working memory tasks is a reflection of sensory storage, the notion supported by some lesion studies. On the other hand, there is emerging evidence that the LPFC plays a key role in the maintenance of sensory information not by storing relevant visual signals but by allocating visual attention to such stimuli. In this study, we addressed this question by examining the effects of unilateral LPFC lesions during a working memory task requiring monkeys to compare directions of two moving stimuli, separated by a delay. The lesions resulted in impaired thresholds for contralesional stimuli at longer delays, and these deficits were most dramatic when the task required rapid reallocation of spatial attention. In addition, these effects were equally pronounced when the remembered stimuli were at threshold or moved coherently. The contralesional nature of the deficits points to the importance of the interactions between the LPFC and the motion processing neurons residing in extrastriate area MT. Delay-specificity of the deficit supports LPFC involvement in the maintenance stage of the comparison task. However, because this deficit was independent of stimulus features giving rise to the remembered direction and was most pronounced during rapid shifts of attention, its role is more likely to be attending and accessing the preserved motion signals rather than their storage.
Comparative-Historical Analysis and Development Studies
Authors: Mahoney James
Published: May 2015

This essay first explores how the defining features of comparative-historical analysis (CHA) endow this approach with comparative advantages for substantive research on macro development. It identifies three major traits of CHA that make this tradition an especially powerful approach for the study of development: cased-based research; a focus on context and configurations; and a concern with mechanisms and temporal flow. It then considers what concretely we have learned about the sources of macro development from CHA studies. While some findings are tentative or open to debate, the list of empirical contributions from CHA is quite substantial. Finally, the essay considers some of the frontiers of CHA work on development. Included at this frontier is work on the concept of development itself, displacing the centrality of property institutions with a focus on identity institutions, and moving the focus of analysis from the national level to subnational and supranational levels.
Estrogen regulates luminal progenitor cell differentiation through H19 gene expression
Authors: Basak Pratima , Chatterjee Sumanta , Weger Steven , Bruce M Christine , Murphy Leigh C , Raouf Afshin
Published: May 2015

Although the role of estrogen signaling in breast cancer development has been extensively studied, the mechanisms that regulate the indispensable role of estrogen in normal mammary gland development have not been well studied. Because of the unavailability of culture system to maintain estrogen-receptor-positive (ERα+) cellsin vitro, the molecular mechanisms that regulate estrogen/ERα signaling in the normal human breast are unknown. In the present study, we examined the effects of estrogen signaling on ERα+human luminal progenitors using a modified matrigel assay and found that estrogen signaling increased the expansion potential of these progenitors. Furthermore, we found that blocking ERα attenuated luminal progenitor expansion and decreased the luminal colony-forming potential of these progenitors. Additionally, blocking ERα decreasedH19expression in the luminal progenitors and led to the development of smaller luminal colonies. We further showed that knocking down theH19gene in the luminal progenitors significantly decreased the colony-forming potential of the luminal progenitors, and this phenotype could not be rescued by the addition of estrogen. Lastly, we explored the clinical relevance of the estrogen–H19signaling axis in breast tumors and found that ERα+tumors exhibited a higher expression ofH19as compared with ERα−tumors and thatH19expression showed a positive correlation with ERα expression in those tumors. Taken together, the present results indicate that the estrogen–ERα–H19signaling axis plays a role in regulating the proliferation and differentiation potentials of the normal luminal progenitors and that this signaling network may also be important in the development of ER+breast cancer tumors.
Evidence That the Origin of Naked Kernels During Maize Domestication Was Caused by a Single Amino Acid Substitution intga1
Authors: Wang Huai , Studer Anthony J , Zhao Qiong , Meeley Robert , Doebley John F
Published: May 2015

teosinte glume architecture1 (tga1), a member of the SBP-box gene family of transcriptional regulators, has been identified as the gene conferring naked kernels in maize vs. encased kernels in its wild progenitor, teosinte. However, the identity of the causative polymorphism within tga1 that produces these different phenotypes has remained unknown. Using nucleotide diversity data, we show that there is a single fixed nucleotide difference between maize and teosinte in tga1, and this difference confers a Lys (teosinte allele) to Asn (maize allele) substitution. This substitution transforms TGA1 into a transcriptional repressor. While both alleles of TGA1 can bind a GTAC motif, maize-TGA1 forms more stable dimers than teosinte-TGA1. Since it is the only fixed difference between maize and teosinte, this alteration in protein function likely underlies the differences in maize and teosinte glume architecture. We previously reported a difference in TGA1 protein abundance between maize and teosinte based on relative signal intensity of a Western blot. Here, we show that this signal difference is not due to tga1 but to a second gene, neighbor of tga1 (not1). Not1 encodes a protein that has 92% amino acid similarity to TGA1 and that is recognized by the TGA1 antibody. Genetic mapping and phenotypic data show that tga1, without a contribution from not1, controls the difference in covered vs. naked kernels. No trait differences could be associated with the maize vs. teosinte alleles of not1. Our results document how morphological evolution can be driven by a simple nucleotide change that alters protein function.
Hacer como si nada hasta producir nada
Authors: Moreno Cardozo Belén Del Rocío
Published: May 2015

La indiferencia ante la matanza en masa fue novedad de la historia del siglo XX. Una tríada de “como si”, plenos de consecuencias, la especifican: “como si no viera”, “como si no escuchara”, “como si no existiera”… De allí, emerge una sentencia inapelable, “¡No eres nada!”, cuya figura queda realizada en el “musulmán” de los campos de concentración. Atendiendo a algunos inquietantes testimonios, trataré de trazar las coordenadas, tanto subjetivas como discursivas, que especifican esta sombría novedad de nuestra época.
La indiferencia como instrumento de poder
Authors: Staude Sergio Carlos
Published: May 2015

La indiferencia como respuesta ante las situaciones de horror que provoca la guerra llega a adquirir diferentes funciones. Puede ser un indicador del resguardo necesario para tramitar lo traumático de los acontecimientos, también un modo de desmentir la responsabilidad de estos o bien ser un instrumento siniestro de poder destinado a garantizar la eficacia de quienes ejercen la violencia, neutralizar las respuestas del medio social y marginar las reacciones posibles de las víctimas. Se destacan los recursos que aportan el psicoanálisis, la creación ficcional del arte y, en particular, los esfuerzos de legitimación de la justicia para paliar los efectos iatrogénicos de la indiferencia.
La persistencia de la angustia: memoria, ausencia y voz en el videoarte colombiano
Authors: Acosta Martínez Carolina
Published: May 2015

Parece que la estética no tiene lugar en un contexto conflictivo como el colombiano, pero los artistas locales insisten en entre-mostrar con sus obras esos reales a los cuales intentamos dar la espalda para resguardarnos. En este orden de ideas, este artículo pretende resaltar el carácter ético de un conjunto de obras colombianas de videoarte que son llamadas a “declarar” sobre las condiciones socioculturales bajo las cuales vieron la luz. Con su apelación a la memoria, la ausencia y la voz, parece que estas obras buscan angustiar al espectador creando sobresaltos en la profusión de textos e imágenes banales y obsolescentes que ofrecen los medios de comunicación (incluyendo el ya famoso significante “posconflicto”) como distractores ante los horrores de la guerra.
Poder y terror en La casa grande de Álvaro Cepeda Samudio. Una lectura de la modernidad en Colombia
Authors: Palacios Danilo
Published: May 2015

Más allá de ser una narrativa de la Masacre de las Bananeras, el libro de Cepeda Samudio condensa, en las relaciones entre sus personajes, algunas características del tránsito de Colombia hacia la modernidad y su asimilación de las lógicas del capitalismo. El contexto sociopolítico en el que Cepeda escribe su obra comparte características estructurales con aquel que el autor trata de re-escribir. Este artículo se propone entonces explorar cómo el autor crea nuevos sentidos y significados a partir de las interpretaciones que cada personaje hace de la Masacre desde condiciones políticas y sociales concretas y diferentes. Se muestra aquí que el argumento de la novela está atravesado por una asociación político-religiosa sobre la cual inició la edificación del capitalismo moderno en Colombia.
Effect of Charge-balancing Species on Sm3+ Incorporation in Calcium Vanadinite
Authors: Gilbert M. R.
Published: May 2015

Apatites are often seen as good potential candidates for the immobilization of halide-rich wastes. In particular, phosphate apatites have received much attention in recent years, however, their synthesis often produces complicated multi-phase systems, with a number of secondary phases forming [1.2]. Calcium vanadinite (Ca5(VO4)3Cl) demonstrates a much simpler phase system, with only a single Ca2V2O7 secondary phase which can easily be retarded by the addition of excess CaCl2. However, when doping with SmCl3 (as an inactive analogue for AnCl3) the Sm forms a wakefieldite (SmVO4) phase rather than being immobilized within the vanadinite, a result of having to form an energetically unfavourable Ca vacancy in order for the lattice to remain neutral overall. It has been postulated that charge-balancing the lattice via co-substitution of a monovalent cation will be less disfavoured and therefore help stabilise formation of a (Ca5-2xSmxAx)(VO4)3Cl solid solution (A = monovalent cation). This has been investigated using a combined modelling and experimental approach. Static lattice calculations performed using Li+, Na+ and K+ as charge-balancing species have shown the energy cost to be less than half that of charge-balancing via formation of a Ca vacancy. As a result, solid state synthesis of (Ca5-2xSmxLix)(VO4)3Cl, (Ca5−2xSmxNax)(VO4)3Cl and (Ca5-2xSmxKx)(VO4)3Cl solid solutions have been trialled, and analysis of the resulting products has shown a significant reduction in both the SmVO4 and Ca2V2O7 secondary phases across all dopant levels.
Analiza wybranych efektów sezonowości stóp zwrotu na rynku srebra w okresie 30.10.2003-31.12.2013
Authors: Borowski Krzysztof
Published: May 2015

This paper presents a study on the prevalence of selected effects of seasonality in silver prices quoted on the London Metal Exchange. The study was conducted for prices in the period from 30.10.2003 to 31.12.2013, and is based on 3172 observations. The results clearly indicate the presence of some seasonality effects in the case of commodities. While some of the results confirm the findings of other writers that have looked at financial markets, others contradict earlier research.
Inwestowanie społecznie odpowiedzialne - przejściowa moda czy trwała tendencja?
Authors: Duliniec Aleksandra
Published: May 2015

The dynamic growth of socially responsible investing has been observed globally in the last decade. The determinants of such investment decisions are described in the paper. A variety of criteria - both negative and positive - can be used in putting together a portfolio. The positive screening of companies to be included in a socially responsible portfolio is based mainly on environmental, social and governance (ESG) issues. However, because there is no explicit evidence that ethical (responsible) funds generate higher returns than conventional funds, it is worth considering the future of socially responsible investments. Will they continue to grow or, after a period of increased interest in social and ethical factors (undoubtedly as the result of the global financial crisis), will they lose their appeal? The paper discusses that issue.
Zmiany regulacyjne a rozwój pochodnych instrumentów kredytowych na polskim rynku finansowym
Authors: Jurkowska Aleksandra
Published: May 2015

The positive effects of the development of credit derivatives is accompanied by new areas of risk that threaten financial stability. Due to the phase of the market development (the foregoing development barriers were regulatory, procedural and technological constraints) the level of risk associated with credit derivatives in Poland is not comparable to the risk observed in developed ones. The new threats are supposed to be reduced by recent regulatory changes (implementing EMIR, the Regulation on short selling and certain aspects of credit default swaps and ISDA standards). Achieving this goal will enable the stable development of the credit derivatives market and will increase the chances for effective credit risk allocation in Poland. Some of the solutions may, however, have negative consequences: new requirements for the establishment and functioning of the CCP are not conducive to the transparency of derivatives trading, while the prohibition of „naked swaps" trading can increase the risk premium. This will be especially discernible in countries with weaker financial and economic potential, including Poland.
Determinanty rozwoju rynku emisji pierwotnych akcji na Giełdzie Papierów Wartościowych w Warszawie
Authors: Ostrowska Elżbieta , Deryło Marta
Published: May 2015

The article defines the term "initial public offerings", and identifies and classifies the determinants of the development of the initial public offerings market on the Warsaw Stock Exchange. The determinants are divided into those associated with how companies function and those related to the environment. We analyse trends in the IPO market on the basis of these criteria: the origin of the companies debuting on the market, their dependence on the WIG index, the increase in capitalisation, the number of withdrawals of companies on the stock exchange, the increase in the number of investment accounts, and GDP.
Teoria opcji i teoria gier. Porównanie narzędzi zarządzania ryzykiem kredytowym
Authors: Paliński Andrzej
Published: May 2015

The purpose of this article is to determine whether the theoretical models derived from option pricing theory and game theory correctly determine the interest rate on bank loans. First, the interest rates were calculated from the option model developed by Moody's-KMV. Obtained in this way, interest rates were compared with the real interest rate on bank loans of Polish publicly listed companies. It turns out that the theoretical interest rate is generally much lower than the actual one. A model built on the basis of the game theory and the concept of the liquidation value was then used, and on that basis theoretical interest rates were calculated using Monte Carlo simulation. In this case, divergence of the theoretical loan rates from the actual ones also proved significant. It seems that, in setting interest rates, Polish banks use many factors, not only the market values of company assets and their volatility.
Brak arbitrażu na rynkach z proporcjonalnymi kosztami transakcji
Authors: Rygiel Agnieszka
Published: May 2015

The aim of the paper was to present in a clear and unified way various results concerning the absence of arbitrage in the modelling of financial markets with proportional transaction costs. The absence of weak and strict arbitrage opportunities criteria in a finite time horizon discrete time market model are given. Sufficient conditions for the absence of simple arbitrage (i.e. arbitrage over simple investment strategies) in a continuous time market model are presented. Special attention is devoted to transactions without short selling.
Credit-Market Sentiment and the Business Cycle
Authors: López-Salido J. David , Stein Jeremy C. , Zakrajsek Egon
Published: May 2015

Using U.S. data from 1929 to 2015, we show that elevated credit-market sentiment in year t-2 is associated with a decline in economic activity in years t and t+1. Underlying this result is the existence of predictable mean reversion in credit-market conditions. When credit risk is aggressively priced, spreads subsequently widen. The timing of this widening is, in turn, closely tied to the onset of a contraction in economic activity. Exploring the mechanism, we find that buoyant credit-market sentiment in year t-2 also forecasts a change in the composition of external finance: Net debt issuance falls in year t, while net equity issuance increases, consistent with the reversal in credit-market conditions leading to an inward shift in credit supply. Unlike much of the current literature on the role of financial frictions in macroeconomics, this paper suggests that investor sentiment in credit markets can be an important driver of economic fluctuations.
Follow-up care of children suffered from burns
Authors: Afonichev Konstantin Aleksandrovich , Filippova Olga Vasilievna
Published: May 2015

Outcomes of III-VI AB degree burns in children,regardless of the nature of treatment in the acute andrecovery period, are the development of scar contractures and deformities of the joints. However, thecorrect organization of follow-up care and rehabilitation treatment can significantly reduce the severity and facilitates the full recovery of the affected segment. Based on the analysis of their own material, the author defines the early stage of rehabilitation in these patients before full maturation of scar tissue or before the formation of functionally significant joint contractures, and later period, when there are indications for surgical rehabilitation. In the early period, follow-up care is recommended in 1 month after discharge and then on a quarterly basis, and with the appearance of deformities - at least once in 2 months. At the2nd stage of rehabilitation, older children and children of secondary school age are subject to follow-up care at least 1 time per year of primary school age - atleast once in 6 months, preschool children - every3 months. The proposed assessment of scar tissuehelps to determine the terms of follow-up care. Usingthis scheme of follow-up care and appropriate treatment allowed the author to obtain excellent and goodresults in 87-90 % of cases at the stages of rehabilitaion.
Central polydactyly: an alternative method of treatment
Authors: Govorov Anton Vladimirovich , Golyana Sergei Ivanovich , Zavarukhin Vladimir Ivanovich , Safonov Andrey Valerievich
Published: May 2015

Polydactyly is a rare congenital malformationcharacterized by an increase in the number of segments of hand ray. Central polydactyly is much rarerthan other types of polydactyly and is characterizedby a doubling of the segments of the second, thirdand fourth fingers. The main methods of surgicaltreatment of central polydactyly consist in the resection of additional segments and removal of the existing union. Often, the result of this treatment is the development of secondary deformities, leading to unsatisfactory results. The article describes the clinical example of microsurgical reconstruction of the patient’s hand with central polydactyly of both hands and presentation of long-term outcome.
European initiatives for better training in medicines development
Authors: Hardman Mike
Published: May 2015

In the last decade, the environment for medicines development has undergone unprecedented change, including: a shift from predominantly big Pharma to one of extensive industry–academia and SME partnerships and collaborations, greater emphasis on understanding the molecular basis of disease for stratified and personalised medicine, and a focus on societal/patients’ needs and priorities.A variety of European initiatives have been established to support the training of scientists/professionals involved in medicines development in order to respond to this constantly changing, demanding, and chaotic landscape. Some of these initiatives are directed specifically at medicines development, some address scientific research including training relevant to medicines development, and some support general training needs which can include medicines development.There are a number of European initiatives supporting better training in medicines development. They differ in their approach, ranging from IMI (specific to medicines development) to Erasmus+ (boosting skills and employability in all areas). The scope, budgets, and requirements differ considerably and they each have to be reviewed in detail to decide which might be the most appropriate for a particular target group. The common theme is to support the aims of the European Research Area (ERA), i.e., a significant improvement in Europe’s research performance to promote growth and job creation.
Scanline in the Kainer Formation and its relationship with the major faults of the Edwards group limestones at Medina Lake, Texas
Authors: Neumann Virgínio Henrique , Barbosa José Antônio , Miranda Tiago Siqueira de , Lima Rafael Pereira de , Silveira Ana Cláudia da , Cabral Flávia Araújo de Arruda , Correia Filho Osvaldo José , Meneses Filho José Acioli
Published: May 2015

O objetivo principal deste trabalho é avaliar as relações gerais entre os dados de fraturas coletados nos trabalhos de campo e as principais falhas ocorrentes nos calcários do Grupo Edwards na região do lago de Medina (proximidades de Santo Antônio), no Texas. Observações de campo incluíram as relações entre scanline e porosidade. As observações de campo, combinadas com a interpretação de análise gráfica, ajudaram na modelagem do padrão de distribuição das fraturas de um reservatório fraturado análogo. As principais direções dos calcários do Grupo Edwards é 60-80Az. Nos afloramentos estudados foram observadas uma grande falha de direção 70Az e outras duas menores de direção 75Az. Este conjunto de falhas esta formando um pequeno graben. Dois scanlines foram executados na superfície de uma camada cinza escura de um grainstone, na qual foram observadas porosidades tipo vugular grande (microcavernas). Outras porosidades do tipo vugular grande foram observadas nas interseções das fraturas nas paredes dos afloramentos estudados. Um cimento branco de calcita foi observado preenchendo fraturas nas camadas de coloração cinza-escura de grainstone. Os gráficos com as informações sobre a distribuição das aberturas das fraturas nos calcários do Grupo Edwards de ambos os afloramentos estudados, mostraram resultados semelhantes, indicando a continuidade do padrão de fraturamento neles. O padrão de faturamento e as falhas também apresentam uma boa correlação com os padrões regionais. Estas falhas são de cunho regional. As porosidades do tipo vugular se encontram nos cruzamentos das fraturas. A média de fraturas abertas por metro foi de 0.5 e o espaçamento das fraturas abertas variou de 5 a 7 fraturas por metro.
Serpulide (annelida, polychaeta) do cretáceo inferior da Bacia Sergipe, Brasil
Authors: Vieira Fabiana Silva , Dantas Mário André Trindade , Sobral Anderson da Conceição Santos , Almeida Leonardo Ferreira de , Zucon Maria Helena
Published: May 2015

Fósseis de Serpula sergipensis Beurlen, 1965 (Serpulidae) foram encontrados em rochas da formação Riachuelo, Bacia de Sergipe, Brasil (10o43’389” S e 37o10’780” W). Esta espécie é descrita, e ilustrada, com base em sessenta fragmentos de tubos calcários. Os tubos de habitação de S. sergipensis são pequenos, solitários, em forma de gancho, com seção transversal quase circular, e com o aumento moderado do diâmetro (1.5 a 4.5 mm) do tubo. Os tubos podem ocorrer isolados, e são ornamentados com finos anéis de crescimento. Os amonóides Eodouvilleiceras e Vectisites simplex confirmam a idade desta assembleia como Aptiana superior. Uma análise preliminar da fauna associada encontrada com os fósseis de S. sergipensis indicam que localidade Porto dos Barcos 2 tratava-se de um ambiente de águas rasas, com baixa energia, alta taxa de oxigênio e nutrientes, habitada por uma comunidade bentônica composto por bivalves, equinoides e espécies de poliquetas.
Separating the role of biotic interactions and climate in determining adaptive response of plants to climate change
Authors: Tomiolo Sara , van der Putten Wim H. , Tielbörger Katja
Published: May 2015

Altered rainfall regimes will greatly affect the response of plant species to climate change. However, little is known about how direct effects of changing precipitation on plant performance may depend on other abiotic factors and biotic interactions. We used reciprocal transplants between climatically very different sites with simultaneous manipulation of soil, plant population origin, and neighbor conditions to evaluate local adaptation and possible adaptive response of four Eastern Mediterranean annual plant species to climate change. The effect of site on plant performance was negligible, but soil origin had a strong effect on fecundity, most likely due to differential water retaining ability. Competition by neighbors strongly reduced fitness.

We separated the effects of the abiotic and biotic soil properties on plant performance by repeating the field experiment in a greenhouse under homogenous environmental conditions and including a soil biota manipulation treatment. As in the field, plant performance differed among soil origins and neighbor treatments. Moreover, we found plant species‐specific responses to soil biota that may be best explained by the differential sensitivity to negative and positive soil biota effects. Overall, under the conditions of our experiment with two contrasting sites, biotic interactions had a strong effect on plant fitness that interacted with and eventually overrode climate. Because climate and biotic interactions covary, reciprocal transplants and climate gradient studies should consider soil biotic interactions and abiotic conditions when evaluating climate change effects on plant performance.
Stream invertebrate productivity linked to forest subsidies: 37 stream‐years of reference and experimental data
Authors: Wallace J. Bruce , Eggert Susan L. , Meyer Judy L. , Webster Jackson R.
Published: May 2015

Riparian habitats provide detrital subsidies of varying quantities and qualities to recipient ecosystems. We used long‐term data from three reference streams (covering 24 stream‐years) and 13‐year whole‐stream organic matter manipulations to investigate the influence of terrestrial detrital quantity and quality on benthic invertebrate community structure, abundance, biomass, and secondary production in rockface (RF) and mixed substrates (MS) of forested headwater streams. Using a mesh canopy covering the entire treatment stream, we examined effects of litter exclusion, small‐ and large‐wood removal, and addition of artificial wood (PVC) and leaves of varying quality on organic matter standing crops and invertebrate community structure and function. We assessed differences in functional feeding group distribution between substrate types as influenced by organic matter manipulations and long‐term patterns of predator and prey production in manipulated vs. reference years. Particulate organic matter standing crops in MS of the treatment stream declined drastically with each successive year of litter exclusion, approaching zero after three years. Monthly invertebrate biomass and annual secondary production was positively related to benthic organic matter in the MS habitats. Rockface habitats exhibited fewer changes than MS habitats across all organic matter manipulations. With leaf addition, the patterns of functional group distribution among MS and RF habitats returned to patterns seen in reference streams. Secondary production per unit organic matter standing crop was greatest for the leaf addition period, followed by the reference streams, and significantly less for the litter exclusion and wood removal periods. These data indicate that the limited organic matter remaining in the stream following litter exclusion and wood removal was more refractory than that in the reference streams, whereas the added leaf material was more labile and readily converted into invertebrate production. Predator production and total production were tightly coupled in reference and treatment streams, indicating strong relationships between predators and their prey. Results from the artificial wood addition demonstrate that physical structure alone will not restore invertebrate productivity without detrital resources from the riparian forest. Our long‐term studies conducted over three decades at the ecosystem scale unequivocally show the necessity of maintaining and restoring aquatic–terrestrial linkages in forested headwater streams.
Potential Use of Archaeological Snail Shells for the Calculation of Local Marine Reservoir Effect
Authors: Carvalho Carla , Macario Kita , Isabela De Oliveira Maria , Oliveira Fabiana , Chanca Ingrid , Alves Eduardo , Souza Rosa , Aguilera Orangel , Douka Katerina
Published: May 2015

Shellmounds are archaeological sites found across the Brazilian coast and form an important record of the human occupation of this area during the Holocene. The presence of both terrestrial and marine remains within the same archaeological context enables the comparison of different carbon reservoirs. There is only a small number of similar studies for the coast of south-southeastern Brazil. Previous work was based on the analysis of pre-bomb shells from museum collections and paired charcoal/marine shells from archaeological sites. This article assesses the potential use of terrestrial shells as representative of atmospheric carbon reservoir in the calculation of the marine reservoir effect (MRE) of the southeastern Brazilian coast. The presence of both terrestrial and marine shells over several archaeological layers represents a great potential for calculating reservoir corrections and their temporal variation.
Weldability of S500MC Steel in Underwater Conditions
Authors: Fydrych D. , Łabanowski J. , Rogalski G. , Haras J. , Tomków J. , Świerczyńska A. , Jakóbczak P. , Kostro Ł.
Published: May 2015

Wet welding with the use of covered electrodes is one of the methods of underwater welding. This method is the oldest, the most economic and the most versatile. The main difficulties during underwater wet welding are: high cooling rates of the joint, the presence of hydrogen in the arc area and formation of hard martensitic structure in the weld. These phenomena are often accompanied by porosity of welds and large number of spatters, which are more advanced with the increase of water depth. In this paper result of non-destructive tests, hardness tests and metallographic observations of S500MC steel joints performed underwater are presented. The weldability of 500MC steel at water environment was determined
Measurement of Force Components and Ra Surface Roughness Parameter During Grinding Titanium Alloy
Authors: Grdulska A.
Published: May 2015

The paper deals with the measurements of selected parameters during grinding process of aerospace industry alloy. Grinding is one of the most important methods of shaping machine elements. As a result of grinding with high dimensional and shape accuracy as well as with the expected parameters describing the state of the surface layer (SL) should be obtained. Grinding difficult to machine materials used in the aerospace industry is an issue currently being examined by various research centres. An excellent example is the analysis of the grinding process of titanium alloys, as these materials have very poor machinability due to the tendency to adherence to abrasive materials, low thermal conductivity, high strength and compliance at elevated temperatures, which may adversely impact on the quality of SL. A number of factors influence on shaping SL. Worth mentioning are mechanical and thermal phenomena, as well as the type of cutting fluid and abrasive materials
Effect of Carbon Content in Stainless Steels on Quantity of Grinding Energy
Authors: Wójcik R.
Published: May 2015

The paper presents a study of the process of grinding stainless steels with different carbon contents. Verified the size and scope of the energy which is introduced in the surface layers for different types of abrasive grains and binders. The influence of parameters in plunge grinding process was considered in studies. The energy ratio was used for this purpose, which was calculated by multiplying energy and time of grinding wheel contact with the workpiece. To investigate influence of different carbon content on the level of energy density generated during grinding process special parameter Bp have been evaluated. The grinding tests were conducted in dry grinding technique.
Degradation of Microstructure and Mechanical Properties of 15HM Steel after 420 000 Hours of Service
Authors: Golański G. , Pietryka I. , Jasak J. , Słania J. , Urbańczyk P. , Wieczorek P.
Published: May 2015

The results of a microstructure examination and mechanical properties of 15HM (13CrMo4-5) steel are presented in the article. The examined elements are the samples taken from the live steam pipeline serviced for about 420 000 hours at the temperature of about 510°C, and pressure of 11 MPa. It has been shown that after long-term operation the examined steel has a ferritic-pearlitic microstructure with a dominant content of quasipolygonal ferrite. The processes of fragmentation of lamellar precipitates and their spheroidization were observed in pearlite. On the grain boundaries, single lamellar precipitations were observed. Moreover, numerous precipitations at the interface of three grain boundaries were revealed. The examined steel, despite its long-term service time, was characterized by the strength properties (YS, TS) slightly lower than the required minimum, the impact energy value KV equal to 20 J, and the transition temperature shifted to a temperature above zero. Relatively low level of degradation of the microstructure and mechanical properties of the investigated steel can result from high stability of the ferritic-pearlitic microstructure.
Morphological and Chemical Relationships in Nanotubes Formed by Anodizing of Ti6al4v Alloy
Authors: Kaczmarek- Pawelska A. , Krasicka- Cydzik E.
Published: May 2015

The electrochemical formation of oxide nanotubes on the Ti6Al4V alloy has been so far difficult due to easy dissolution of vanadium reach β-phase of the two phase material. Due to the topographical heterogeneity of the anodic layer in nano and microscale at anodizing of the Ti6Al4V alloy we focused to establish the relationships between nanotube diameters on both phases of the alloy and fluorides concentration in electrolyte. We studied the effect of fluoride concentration (0.5-0.7 wt.%) in 99% ethylene glycol on morphological parameters of nanotube layer on the Ti6Al4V alloy anodized at 20V for 20 min. Nanotubes with diameter ~40-50 nm ±5nm on the entire Ti6Al4V alloy surface in electrolyte containing 0.6% wt. NH4F were obtained. Microscale roughness studies revealed that nanotubular layer on α-phase is thicker than on β-phase. The annealing of nanotube layers at 600°C for 2h in air, nitrogen and argon, typically performed to improve their electrical properties, influenced chemical composition and morphology of nanotubes on the Ti6Al4V alloy. The vanadium oxides (VO2, V2O3, V2O5) were present in surface nanotube layer covering both phases of the alloy and the shape of nanotubes was preserved after annealing in nitrogen.
Evaluation of Microstructural Changes of S235 Steel after Rolling on the Basis of Microscopic Observations and Eddy Current Non-Destructive Method
Authors: Kukla D. , Bałkowiec A. , Grzywna P.
Published: May 2015

The aim of the study was to determine the microstructure and residual stress changes which appears in the S235 steel (which is designed for operating in elevated temperatures) during cold rolling. The changes of orientation, both morphological and crystallographic, are occurring as a result of the rolling process. Analysis of the results allowed to determine the change in grain morphology (size, shape), determination of grain morphology of the rolling direction and determination of crystallographic texture. The dislocation density present in the material before and after the cold rolling process was estimated on the basis of dislocation structure images obtained via transmission electron microscope. The observed microstructural changes were correlated with the results of nondestructive testing using eddy current method. They allowed for the identification of the state of stress measured on three different surfaces of the rolled sheet (parallel and perpendicular to the rolling direction). As the result the usability of using the non - destructuve techniques of stress level determination was proved.
Characterisation and Optical Studies of Copper Oxide Nanostructures Doped with Lanthanum Ions
Authors: Varughese G. , Rini V. , Suraj S.P. , Usha K.T.
Published: May 2015

Copper Oxide is an extensively studied group II-VI semiconductor with optical properties. It exhibits a wide variety of morphologies in the nano regime that can be grown by tuning the growth habit of the CuO crystal. CuO nano materials with an average particle size of 15-27 nm are synthesized by chemical route. XRD, SEM, FTIR UV-Vis and EDS characterize the samples. The percentage of doping material is confirmed from the EDS spectra. The average crystal size of the prepared CuO: La nanopowder is determined by XRD. The UV absorption spectra revealed the absorption edge at wavelength 389 nm indicating the smaller size of CuO:La nano particle. The optical direct band gap energy of doped CuO nanoparticle is found to be in the range 3.149 eV. The increasing red shift with decreasing particle size suggests that the defects responsible for the intra gap states are primarily surface defect. The La doped CuO is highly effective and can significantly enhance the photo catalytic degradation.
Analysis of The Possibility of Applying of Alloy and Composite Coatings after Plastic Working in Shipbuilding
Authors: Dyl T.
Published: May 2015

Alloy and composite coatings are widely used in engineering, automotive and shipbuilding because of the possibility of improving the operational characteristics of the surface layer (mechanical, tribological, corrosion and decorative). The welding technology of applying alloy and composite coatings is widely used. The technology of infrasound thermal spraying of metal matrix composite coatings was presented. It is a simple technology and a very useful one in ship machinery regeneration during the cruise craft (e.g. internal combustion engines, torque pumps, separators). The metal matrix composite coatings must undergo finishing due to high surface roughness after application. Coatings obtained by thermal spraying have a large surface roughness, it is therefore necessary to make finishing coatings. Due to economic and technological developments it is essential that the coating was thin, abrasion-resistant, high smoothness, and the finishing was of chip that is not cause material loss. In order to ensure quality of technology offered the elements of the of machines used in shipbuilding of cold working by rolling, with small values of strain ratio, ultimately as a finishing alloy and composite coating is planned to use surface plastic forming of machine parts.
Expenditures on Collective and Individual Services: Discussion on the Classification of Government Expenditures with Regard to their Inclusion into Growth Models
Authors: Machová Zuzana , Kotlán Igor
Published: May 2015

The aim of this paper is to examine the effects of government expenditures on long-run economic growth in developed countries using their different breakdown. Empirical analysis is performed for a panel of 34 OECD countries in the period 2000-2012. Above all, the results support the idea that conclusions of previous studies on this topic may be strongly distorted by inappropriate classification of expenditures, typically in the case of expenditures on education and health. These are usually considered productive and thus growth enhancing, but if their part of R&D expenditures is detached, their effect on growth is in fact negative. In general, it is concluded that government expenditures on individual services have negative effects on growth, while the impact of expenditures on collective services is positive.
Climate change increases the drought risk in Central European forests: What are the options for adaptation?
Authors: Hlásny Tomáš , Mátyás Csaba , Seidl Rupert , Kulla Ladislav , Merganičová Katarína , Trombik Jiří , Dobor Laura , Barcza Zoltán , Konôpka Bohdan
Published: May 2015

The paper presents information on the projected drought exposure of Central Europe, describes the anticipated dynamics of the regional forests, and identifies measures facilitating the adaptation of forests to climate change-induced drought risk. On the basis of an ensemble of climate change scenarios we expect substantial drying in southern Slovakia and Hungary, while such trends were found to be less pronounced for the Czech Republic and Austria. In response to these climate trajectories, a change in species composition towards a higher share of drought tolerant species as well as the use of drought resistant provenances are identified as paramount actions in forest adaptation in the region. Adaptation to aggravating climate change may need to use artificial regeneration to enrich local gene pools and increase the drought tolerance of stands. Increasing risks from pests, pathogens and other disturbances are expected as a result of more frequent and severe droughts, underlining the need to put a stronger focus on risk management principles rather than on indicators of productivity in silviculture and forest planning. A consolidation of disturbance monitoring systems and a broader use of pest dynamics and hazard rating models are paramount tools to facilitate this adaptation process in forest management. The effectiveness of all the suggested measures needs to be controlled by efficient forest monitoring systems, the consolidation of which seems to be a timely task. Systematic and long-term implementation of the presented measures should increase forest stability and resilience, and further secure the sustainable provision of ecosystem services under climate change.