143 research outputs found
Markers of success: A study of twins' instructed second language acquisition
We examined the association between proficiency in instructed second language acquisition (ISLA) and previous bilingualism, starting age of ISLA, language anxiety and attitude. The analyses were conducted on 564 adolescent Australian twins. Additionally, by examining discrepancies within approximately 100 pairs of monozygotic twins, we sought to specifically identify the environmental effects related to attitude and anxiety on achievement (i.e. with genetic effects removed). We found a clear relationship between attitude towards language learning and proficiency in the second language. Furthermore, the analyses on the monozygotic twins point to the possibility that higher language anxiety is associated with higher proficiency. On the other hand, bilingualism and starting age of ISLA appear to be unrelated to proficiency in the language being learned.</p
Bone marrow-derived mesenchymal stem cells become anti-angiogenic when chondrogenically or osteogenically differentiated:implications for bone and cartilage tissue engineering
Osteochondral tissue repair requires formation of vascularized bone and avascular cartilage. Mesenchymal stem cells stimulate angiogenesis both in vitro and in vivo but it is not known if these proangiogenic properties change as a result of chondrogenic or osteogenic differentiation. We investigated the angiogenic/antiangiogenic properties of equine bone marrow-derived mesenchymal stem cells (eBMSCs) before and after differentiation in vitro. Conditioned media from chondrogenic and osteogenic cell pellets and undifferentiated cells was applied to endothelial tube formation assays using Matrigelâ˘. Additionally, the cell secretome was analysed using LC-MS/MS mass spectrometry and screened for angiogenesis and neurogenesis-related factors using protein arrays. Endothelial tube-like formation was supported by conditioned media from undifferentiated eBMSCs. Conversely, chondrogenic and osteogenic conditioned media was antiangiogenic as shown by significantly decreased length of endothelial tube-like structures and degree of branching compared to controls. Undifferentiated cells produced higher levels of angiogenesis-related proteins compared to chondrogenic and osteogenic pellets. In summary, eBMSCs produce an array of angiogenesis-related proteins and support angiogenesis in vitro via a paracrine mechanism. However, when these cells are differentiated chondrogenically or osteogenically, they produce a soluble factor(s) that inhibits angiogenesis. With respect to osteochondral tissue engineering, this may be beneficial for avascular articular cartilage formation but unfavourable for bone formation where a vascularized tissue is desired
Performance of bias corrected MPEG rainfall estimate for rainfall-runoff simulation in the upper Blue Nile Basin, Ethiopia
In many developing countries and remote areas of important ecosystems, good quality precipitation data are neither available nor readily accessible. Satellite observations and processing algorithms are being extensively used to produce satellite rainfall products (SREs). Nevertheless, these products are prone to systematic errors and need extensive validation before to be usable for streamflow simulations. In this study, we investigated and corrected the bias of Multi-Sensor Precipitation EstimateâGeostationary (MPEG) data. The corrected MPEG dataset was used as input to a semi-distributed hydrological model Hydrologiska ByrĂĽns Vattenbalansavdelning (HBV) for simulation of discharge of the Gilgel Abay and Gumara watersheds in the Upper Blue Nile basin, Ethiopia. The result indicated that the MPEG satellite rainfall captured 81% and 78% of the gauged rainfall variability with a consistent bias of underestimating the gauged rainfall by 60%. A linear bias correction applied significantly reduced the bias while maintaining the coefficient of correlation. The simulated flow using bias corrected MPEG SRE resulted in a simulated flow comparable to the gauge rainfall for both watersheds. The study indicated the potential of MPEG SRE in water budget studies after applying a linear bias correction
Cancer prevention and therapy through the modulation of the tumor microenvironment
Cancer arises in the context of an in vivo tumor microenvironment. This microenvironment is both a cause and consequence of tumorigenesis. Tumor and host cells co-evolve dynamically through indirect and direct cellular interactions, eliciting multiscale effects on many biological programs, including cellular proliferation, growth, and metabolism, as well as angiogenesis and hypoxia and innate and adaptive immunity. Here we highlight specific biological processes that could be exploited as targets for the prevention and therapy of cancer. Specifically, we describe how inhibition of targets such as cholesterol synthesis and metabolites, reactive oxygen species and hypoxia, macrophage activation and conversion, indoleamine 2,3-dioxygenase regulation of dendritic cells, vascular endothelial growth factor regulation of angiogenesis, fibrosis inhibition, endoglin, and Janus kinase signaling emerge as examples of important potential nexuses in the regulation of tumorigenesis and the tumor microenvironment that can be targeted. We have also identified therapeutic agents as approaches, in particular natural products such as berberine, resveratrol, onionin A, epigallocatechin gallate, genistein, curcumin, naringenin, desoxyrhapontigenin, piperine, and zerumbone, that may warrant further investigation to target the tumor microenvironment for the treatment and/or prevention of cancer
The Structure of Episodic Memory: Ganeri's âMental Time Travel and Attentionâ
We offer a framework for assessing what the structure of episodic memory might be, if one accepts the Buddhist denial of persisting selves. This paper is a response to Jonardon Ganeri's paper "Mental time travel and attention", which explores Buddhaghosa's ideas about memory. (It will eventually be published with a reply by Ganeri)
Efficient use of water for irrigation in the upper midwest
The objectives of this multidisciplinary interinstitutional regional study on the efficient use of water for irrigation in the upper Midwest were: (1) to determine parameters needed for existing or improved models of crop response; (2) to relate yield response to costs and revenues by assessing the water demand for irrigation; and (3) to study the demand for irrigation, present and projected, and its availability as related to public allocation decisions. From this series of studies it was concluded that: (1) There are many areas of the Midwest with sufficient groundwater and surface water resources to support the development of irrigation. (2) Soil moisture models indicate that only moderate yield response to irrigation can be expected on high moisture soils; on lighter soils and claypan soils, yield response is significant, even in regions with relatively high precipitation. (3) Irrigation and drainage on claypan soils can dramatically increase corn yields. (4) It appears economically worthwhile for the individual farmer operating on moderate soils or on claypan soils to evaluate capital investments in irrigation along with other capital investments. (5) Increases in yields and persistence of alfalfa due to irrigation appear to be insignificant when compared to conventional management practices; further research is needed. A potential, however, appears to exist for improving adaptation of a1 fa1 fa varieties to soil water deficits.U.S. Geological SurveyU.S. Department of the InteriorOpe
FLUXNET: A New Tool to Study the Temporal and Spatial Variability of Ecosystem-Scale Carbon Dioxide, Water Vapor, and Energy Flux Densities
FLUXNET is a global network of micrometeorological flux measurement sites that measure the exchanges of carbon dioxide, water vapor, and energy between the biosphere and atmosphere. At present over 140 sites are operating on a long-term and continuous basis. Vegetation under study includes temperate conifer and broadleaved (deciduous and evergreen) forests, tropical and boreal forests, crops, grasslands, chaparral, wetlands, and tundra. Sites exist on five continents and their latitudinal distribution ranges from 70°N to 30°S.
FLUXNET has several primary functions. First, it provides infrastructure for compiling, archiving, and distributing carbon, water, and energy flux measurement, and meteorological, plant, and soil data to the science community. (Data and site information are available online at the FLUXNET Web site, http://www-eosdis.ornl.gov/FLUXNET/.) Second, the project supports calibration and flux intercomparison activities. This activity ensures that data from the regional networks are intercomparable. And third, FLUXNET supports the synthesis, discussion, and communication of ideas and data by supporting project scientists, workshops, and visiting scientists. The overarching goal is to provide information for validating computations of net primary productivity, evaporation, and energy absorption that are being generated by sensors mounted on the NASA Terra satellite.
Data being compiled by FLUXNET are being used to quantify and compare magnitudes and dynamics of annual ecosystem carbon and water balances, to quantify the response of stand-scale carbon dioxide and water vapor flux densities to controlling biotic and abiotic factors, and to validate a hierarchy of soil-plant-atmosphere trace gas exchange models. Findings so far include 1) net C02 exchange of temperate broadleaved forests increases by about 5.7 g C m~2 day-1 for each additional day that the growing season is extended; 2) the sensitivity of net ecosystem C02 exchange to sunlight doubles if the sky is cloudy rather than clear; 3) the spectrum of C02 flux density exhibits peaks at timescales of days, weeks, and years, and a spectral gap exists at the month timescale; 4) the optimal temperature of net C02 exchange varies with mean summer temperature; and 5) stand age affects carbon dioxide and water vapor flux densities
Quantitative Concept Analysis
Formal Concept Analysis (FCA) begins from a context, given as a binary
relation between some objects and some attributes, and derives a lattice of
concepts, where each concept is given as a set of objects and a set of
attributes, such that the first set consists of all objects that satisfy all
attributes in the second, and vice versa. Many applications, though, provide
contexts with quantitative information, telling not just whether an object
satisfies an attribute, but also quantifying this satisfaction. Contexts in
this form arise as rating matrices in recommender systems, as occurrence
matrices in text analysis, as pixel intensity matrices in digital image
processing, etc. Such applications have attracted a lot of attention, and
several numeric extensions of FCA have been proposed. We propose the framework
of proximity sets (proxets), which subsume partially ordered sets (posets) as
well as metric spaces. One feature of this approach is that it extracts from
quantified contexts quantified concepts, and thus allows full use of the
available information. Another feature is that the categorical approach allows
analyzing any universal properties that the classical FCA and the new versions
may have, and thus provides structural guidance for aligning and combining the
approaches.Comment: 16 pages, 3 figures, ICFCA 201
Basic income and the right to work: a Keynesian approach
Among the proposals for radical reform of social policy are basic income, which would pay an unconditional cash benefit to all individuals, and the right to work, which would offer guaranteed employment arranged by the state if necessary. This paper examines the macroeconomic consequences of such reform proposals. It sets up a simple Keynesian income-expenditure model that includes basic income and the right to work as alternative methods of providing social assistance, along with the more traditional approach of paying unemployment benefits. The various schemes are compared and contrasted with regard to their implications for employment, stability, distribution, efficiency and the government budget. Potential benefits of basic income or the right to work are emphasised, despite the political obstacles to implementing them
A multi-targeted approach to suppress tumor-promoting inflammation
Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-ÎşB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes
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