140 research outputs found
Compostos orgânicos e resíduos da cadeia produtiva do arroz como substrato para produção de mudas de cana-de-açúcar.
O objetivo do presente trabalho foi determinar o potencial agronômico de substratos produzidos a base de um composto orgânico para a produção, a partir de minitoletes, de mudas de cana-de-açúcar genótipo RB86751
(EIN)FACH? : Komplexität, Wissen, Fortschritt und die Grenzen der Germanistik
Spätestens seit den gesellschaftlichen Modernisierungsschüben in den sechziger Jahren identifiziert auch die Germanistik Erkenntnis- und Wissenszuwachs, ja allgemeiner den "Fortschritt" ihres Fachs, mit Komplexitätserhöhung. Vor diesem Hintergrund erscheint es mir wenig plausibel, die seitdem erfolgten inneren Ausdifferenzierungen und interdisziplinären Grenzüberschreitungen als durch Identitätsverlust, Zerstreuung und Desintegration gekennzeichnete Niedergangsszenarien zu beschreiben. Die Veränderungen gehorchen der immanenten Logik germanistischer Forschung, einer "disziplinierten", auf Leistung ausgerichteten, an kooperativen Großforschungsvorhaben partizipierenden Wissensproduktion
Why theory matters:Analytical strategies of critical psychology
Based on Critical Psychology from the Standpoint of the Subject the article describes analytical concerns and strategies of critical psychology. In a first step, the development of critical psychologies is located in current discussions on the production of knowledge, and three different typical approaches and major steps toward situated critique as a practice of mutual recognition are delineated. This shift, it is argued, has led to a historically new relevance of critique, and two basic analytical elements of critical research are introduced: Everyday conflictuality as the initiating moment of critique as well as the importance of theory for critical inquiry. On this basis a variety of analytic strategies and concepts are presented which inform Critical Psychology from the Standpoint of the Subject and suggest a constituent move from partial perspectives toward situated generalization
Transient Storage as a Function of Geomorphology, Discharge, and Permafrost Active Layer Conditions in Arctic Tundra Streams
Transient storage of solutes in hyporheic zones or other slow-moving stream waters plays an important role in the biogeochemical processes of streams. While numerous studies have reported a wide range of parameter values from simulations of transient storage, little field work has been done to investigate the correlations between these parameters and shifts in surface and subsurface flow conditions. In this investigation we use the stream properties of the Arctic (namely, highly varied discharges, channel morphologies, and subchannel permafrost conditions) to isolate the effects of discharge, channel morphology, and potential size of the hyporheic zone on transient storage. We repeated stream tracer experiments in five morphologically diverse tundra streams in Arctic Alaska during the thaw season (May–August) of 2004 to assess transient storage and hydrologic characteristics. We compared transient storage model parameters to discharge (Q), the Darcy-Weisbach friction factor (f), and unit stream power (ω). Across all studied streams, permafrost active layer depths (i.e., the potential extent of the hyporheic zone) increased throughout the thaw season, and discharges and velocities varied dramatically with minimum ranges of eight-fold and four-fold, respectively. In all reaches the mean storage residence time (tstor) decreased exponentially with increasing Q, but did not clearly relate to permafrost active layer depths. Furthermore, we found that modeled transient storage metrics (i.e., tstor, storage zone exchange rate (αOTIS), and hydraulic retention (Rh)) correlated better with channel hydraulic descriptors such as f and ω than they did with Q or channel slope. Our results indicate that Q is the first-order control on transient storage dynamics of these streams, and that f and ω are two relatively simple measures of channel hydraulics that may be important metrics for predicting the response of transient storage to perturbations in discharge and morphology in a given stream
Surface Energy Budgets of Arctic Tundra During Growing Season
This study analyzed summer observations of diurnal and seasonal surface energy budgets across several monitoring sites within the Arctic tundra underlain by permafrost. In these areas, latent and sensible heat fluxes have comparable magnitudes, and ground heat flux enters the subsurface during short summer intervals of the growing period, leading to seasonal thaw. The maximum entropy production (MEP) model was tested as an input and parameter parsimonious model of surface heat fluxes for the simulation of energy budgets of these permafrost‐underlain environments. Using net radiation, surface temperature, and a single parameter characterizing the thermal inertia of the heat exchanging surface, the MEP model estimates latent, sensible, and ground heat fluxes that agree closely with observations at five sites for which detailed flux data are available. The MEP potential evapotranspiration model reproduces estimates of the Penman‐Monteith potential evapotranspiration model that requires at least five input meteorological variables (net radiation, ground heat flux, air temperature, air humidity, and wind speed) and empirical parameters of surface resistance. The potential and challenges of MEP model application in sparsely monitored areas of the Arctic are discussed, highlighting the need for accurate measurements and constraints of ground heat flux.Plain Language SummaryGrowing season latent and sensible heat fluxes are nearly equal over the Arctic permafrost tundra regions. Persistent ground heat flux into the subsurface layer leads to seasonal thaw of the top permafrost layer. The maximum energy production model accurately estimates the latent, sensible, and ground heat flux of the surface energy budget of the Arctic permafrost regions.Key PointThe MEP model is parsimonious and well suited to modeling surface energy budget in data‐sparse permafrost environmentsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150560/1/jgrd55584.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150560/2/jgrd55584_am.pd
Host Sexual Dimorphism and Parasite Adaptation
Disease expression and prevalence often vary in the different sexes of the host. This is typically attributed to innate differences of the two sexes but specific adaptations by the parasite to one or other host sex may also contribute to these observations
Medium-term fluvial island evolution in a disturbed gravel-bed river (Piave River, Northeastern Italian Alps)
River islands are defined as discrete areas of woodland vegetation surrounded by either water-filled channels or exposed gravel. They exhibit some stability and are not submerged during bank-full flows. The aim of the study is to analyze the dynamics of established, building, and pioneer islands in a 30-km-long reach of the gravel-bed Piave River, which has suffered from intense and multiple human impacts. Plan-form changes of river features since 1960 were analyzed using aerial photographs, and a LiDAR was used to derive the maximum, minimum and mean elevation of island surfaces, and maximum and mean height of their vegetation. The results suggest that established islands lie at a higher elevation than building and pioneer islands, and have a thicker layer of fine sediments deposited on their surface after big floods. After the exceptional flood in 1966 (RI>200 years) there was a moderate increase in island numbers and extension, followed by a further increase from 1991, due to a succession of flood events in 1993 and 2002 with RI>10 years, as well as a change in the human management relating to the control of gravel-mining activities. The narrowing trend (1960-1999) of the morphological plan form certainly enhanced the chance of islands becoming established and this explains the reduction of the active channel, the increase in established islands and reduction of pioneer islands
Strategies to inhibit tumour associated integrin receptors: rationale for dual and multi-antagonists
YesThe integrins are a family of 24 heterodimeric transmembrane cell surface receptors. Involvement in cell attachment to the extracellular matrix, motility, and proliferation identifies integrins as therapeutic targets in cancer and associated conditions; thrombosis, angiogenesis and osteoporosis. The most reported strategy for drug development is synthesis of an agent that is highly selective for a single integrin receptor. However, the ability of cancer cells to change their integrin repertoire in response to drug treatment renders this approach vulnerable to the development of resistance and paradoxical promotion of tumor growth. Here, we review progress towards development of antagonists targeting two or more members of the RGD-binding integrins, notably αvβ3, αvβ5, αvβ6, αvβ8, α5β1, and αIIbβ3, as anticancer therapeutics
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