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Search Results: 1 - 10 of 140597 matches for " Alexandre V. Grose "
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Diversidade e abundancia sazonal da avifauna em duas planícies de maré no estuário da baía da Babitonga, norte de Santa Catarina Diversity and abundance of birds in two tidal flat in Babitonga Bay estuary, north of Santa Catarina state, Brazil
Alexandre V. Grose,Cristiane C. Hillebrant,Marta J. Cremer
Iheringia. Série Zoologia , 2013,
Abstract: Informa es sobre a ocorrência de aves nos ambientes estuarinos de Santa Catarina ainda s o escassas. O objetivo deste trabalho foi registrar a diversidade, abundancia e varia o sazonal das aves em duas planícies de maré na baía da Babitonga. As amostragens foram realizadas durante um ano (maio de 2006 a abril 2007). No total foram identificadas 25 espécies, sendo 15 no Linguado (LG) e 24 na desembocadura do Monte de Trigo (MT). Apenas uma espécie foi exclusiva no LG Himantopus melanurus (Vieillot, 1817), enquanto dez espécies ocorreram apenas no MT. O número de espécies em MT foi superior ao encontrado em LG. A espécie mais abundante em MT foi Rynchops niger (Linnaeus, 1758) e em LG foi Egretta caerulea (Linnaeus, 1758). Durante alguns meses foram registradas espécies migratórias neárticas em ambas as áreas, o que representou um acréscimo na diversidade. A extensa planície de maré formada pelo fechamento do canal do Linguado tem sido muito ocupada por aves, possivelmente pela maior disponibilidade de alimento. Information of birds in estuaries of Santa Catarina is scarce. This work aimed to collect data on diversity, abundance and seasonal variation on this community. Sampling of birds in two tidal flats in Babitonga Bay estuary was carried out during one year (May 2006 to April 2007). A total of 25 species were identified, being 15 in Linguado (LG) and 24 in Monte de Trigo (MT). Only one species was unique in LG (Himantopus melanurus Vieillot, 1817) and 10 in MT. The number of species in MT was higher than in LG due to the conservation condition. The most abundant species on MT was the Black Skimmer [Rynchops niger (Linnaeus, 1758)] and in the LG was the Little Blue Heron [Egretta caerulea (Linnaeus, 1758)]. During some months Nearctic migratory species were recorded in both areas, representing an increase in diversity. The extensive tidal flat formed by the closure of the channel in LG is widely used by birds, possibly because of increased food availability.
Common ground in the transcriptional profiles of wounds and tumors
Richard Grose
Genome Biology , 2004, DOI: 10.1186/gb-2004-5-6-228
Abstract: Tumors have long been described as sharing many histological features with repairing tissues, an idea that likens them to wounds that do not heal [1]. Such an analogy is tempting, as in both cases cell proliferation, survival and migration - in response to a cocktail of growth factors and cytokines - is accompanied by an inflammatory and angiogenic response [2]. Signals facilitating survival and invasion come from many sources in the tumor environment, with tumor cells, fibroblasts and endothelial cells producing various growth and differentiation factors, extracellular matrix proteins and proteases. These signals, together with other factors such as signaling mediated by cell-cell and cell-matrix interactions, activate a wide range of intracellular signaling cascades to affect cell motility and survival [3]. At a wound site, various cell types release the same growth factors and proteases, activating similar downstream signaling pathways [4].Microarray analysis allows the screening of thousands of genes without a prior knowledge of, or bias for, which genes might be involved in the process being studied. It also allows the identification of panels of genes rather than individual ones, which may give a more complete picture of the process under investigation. Recent data have strengthened the link between tumors and wounds by providing molecular evidence of similar gene-expression profiles in keratinocytes at the wound margin and in squamous cell carcinoma [5]. Most recently, microarray studies using an in vitro model of the wound environment have identified a transcriptional signature for stromal fibroblasts, which may prove to be a useful clinical tool in assessing the stage of tumor progression [6].In pioneering work five years ago, the Brown lab used a DNA microarray approach to profile the genetic response of fibroblasts to serum, a fluid to which they should only be exposed in the context of a healing wound [7]. Accordingly, the spectrum of genes whose express
The Determinants of Cash Flows in Greek Bond Mutual Funds
Christos Grose
International Journal of Economic Sciences and Applied Research , 2011,
Abstract: This paper examines the factors that affect inflows – outflows of capital in bond mutual funds that operated in the Greek market during the period 1997-2005. Investors in bond mutual funds do not seek for high gross returns in order to determine their investment decisions incontrast with investors in the stock market. The risk weighted returns however represent a crucial factor in investment decision making. Bond mutual funds that invest primarily in government bonds, appear to be more affected by commissions charged by mutual fundmanagers, since investors avoid mutual funds charging high commissions, while on the other hand investors that prefer corporate bonds show reduced sensitivity in the commissions charged by mutual funds. Investors in government bonds increase their investment positions when stock markets experience small or negative returns, a clue that shows they seek for safe heavens for their investments. This phenomenon is more evident when investors face a temporary period of low stock market returns and is not as strong when low returns in the stock markets are extended to a period of years. In these cases investment positions in bond mutual funds appear to be part of a more permanent investment policy where bond investments are considered to be an integral part of a diversified portfolio.
PERSISTENCE IN PERFORMANCE FOR MUTUAL FUNDS IN PERIODS OF CRISIS
Chris GROSE,Theodoros KARGIDIS
Scientific Bulletin : Economic Sciences , 2012,
Abstract: The study investigates the persistence in performance for a sample of South European funds, domiciled in Portugal, Italy, Greece and Spain. Employing the Sharpe ratio, risk adjusted performance is measured in an attempt to judge the influence of the 2008 crisis and the current debt crisis on funds’ inclination to persist in their previous returns record. Examination period extends from January 2004 to December 2010 incorporating stages of relative stability in the stock and bond markets while also capturing the early stages of the eurozone crisis. We categorize funds as winners and losers in consecutive 6-monthly periods, thus being able to judge persistence in the short run, while our results suggest that the identification of winners and losers could enable us to investigate the possibility to gain investment advantages through this finding. Overall results suggest evidence of persistent results, whether positive or negative, both during the 2008 crisis and the current debt crisis, leading us to deduce that factors leading to performance persistence are not affected by market changes, since medium to long term persistence bypasses any temporary market mischief. This finding could be of use for fund managers aiming at establishing viable investment strategies, at their epicenter being the exploitation of such clues, suggesting persistence in returns. A fund of funds manager employing funds both in equities and fixed income could potentially choose to invest exclusively or more heavily in the winners of previous periods and avoid accordingly poor performers, thus achieving higher returns on average. For this purpose simple investment strategies are employed where we test the outcome of an investment strategy that would invest on fixed income securities by choosing those funds that were winners in the distribution of returns in the previous 6-monthly period, while disinvesting from poor performers and funds switching sides in performance persistence measurement in consecutive periods. The eurozone crisis makes more apparent the need to make use of such anomalies which could result in over performance relative to market benchmarks or reduction in overall losses during periods of unrest in fixed income markets like the one currently faced. Bond funds could also prove a valuable “helping hand” to portfolio managers when equity markets suffer, but that is not guaranteed by all funds under the same market conditions.
The Role of PAS Kinase in PASsing the Glucose Signal
Julianne H. Grose,Jared Rutter
Sensors , 2010, DOI: 10.3390/s100605668
Abstract: PAS kinase is an evolutionarily conserved nutrient responsive protein kinase that regulates glucose homeostasis. Mammalian PAS kinase is activated by glucose in pancreatic beta cells, and knockout mice are protected from obesity, liver triglyceride accumulation, and insulin resistance when fed a high-fat diet. Yeast PAS kinase is regulated by both carbon source and cell integrity stress and stimulates the partitioning of glucose toward structural carbohydrate biosynthesis. In our current model for PAS kinase regulation, a small molecule metabolite binds the sensory PAS domain and activates the enzyme. Although bona fide PAS kinase substrates are scarce, in vitro substrate searches provide putative targets for exploration.
Calling a spade a spade: Mathematics in the new pattern of division of labour
Alexandre V. Borovik
Mathematics , 2014,
Abstract: The growing disconnection of the majority of population from mathematics is becoming a phenomenon that is increasingly difficult to ignore. This paper attempts to point to deeper roots of this cultural and social phenomenon. It concentrates on mathematics education, as the most important and better documented area of interaction of mathematics with the rest of human culture. I argue that new patterns of division of labour have dramatically changed the nature and role of mathematical skills needed for the labour force and correspondingly changed the place of mathematics in popular culture and in the mainstream education. The forces that drive these changes come from the tension between the ever deepening specialisation of labour and ever increasing length of specialised training required for jobs at the increasingly sharp cutting edge of technology. Unfortunately these deeper socio-economic origins of the current systemic crisis of mathematics education are not clearly spelt out, neither in cultural studies nor, even more worryingly, in the education policy discourse; at the best, they are only euphemistically hinted at. This paper is an attempt to describe the socio-economic landscape of mathematics education without resorting to euphemisms.
Orthogonal and Symplectic Black Box Groups, Revisited
Alexandre V. Borovik
Mathematics , 2001,
Abstract: We propose a simple one sided Monte-Carlo algorithm to distinguish, to any given degree of certainty, between certain symplectic and orthogonal groups over fields of odd order. The algorithm does not use an order oracle and works in polynomial time.
Centralisers of Involutions in Black Box Groups
Alexandre V. Borovik
Mathematics , 2001,
Abstract: We discuss basic structural properties of finite black box groups. A special emphasis is made on the use of centralisers of involutions in probabilistic recognition of black box groups. In particular, we suggest an algorithm for finding the $p$-core of a black box group of odd characteristic. This special role of involutions suggest that the theory of black box groups reproduces, at a non-deterministic level, some important features of the classification of finite simple groups.
Representations of the braid group B_n and the highest weight modules of U(sl_{n-1}) and U_q(sl_{n-1})
Alexandre V. Kosyak
Mathematics , 2008,
Abstract: In [1] we have constructed a [n+1/2]+1 parameters family of irreducible representations of the Braid group B_3 in arbitrary dimension using a $q-$deformation of the Pascal triangle. This construction extends in particular results by S.P. Humphries (2000), who constructed representations of the braid group B_3 in arbitrary dimension using the classical Pascal triangle. E. Ferrand (2000) obtained an equivalent representation of B_3 by considering two special operators in the space ${\mathbb C}^n[X].$ Slightly more general representations were given by I. Tuba and H. Wenzl (2001). They involve [n+1/2] parameters (and also use the classical Pascal's triangle). The latter authors also gave the complete classification of all simple representations of $B_3$ for dimension $n\leq 5$. Our construction generalize all mentioned results and throws a new light on some of them. We also study the irreducibility and equivalence of the constructed representations. In the present article we show that all representations constructed in [1] may be obtained by taking exponent of the highest weight modules of U(sl}_2 and U_q(sl_2). We generalize these connections between the representation of the braid group $B_n$ and the highest weight modules of the U_q(sl_{n-1}) for arbitrary} n using the well-known reduced Burau representation.
Organotypic modelling as a means of investigating epithelial-stromal interactions during tumourigenesis
Athina-Myrto Chioni, Richard Grose
Fibrogenesis & Tissue Repair , 2008, DOI: 10.1186/1755-1536-1-8
Abstract: Tumourigenesis is a complex process during which tumour cells acquire a sequence of mutations in genes that directly or indirectly control processes such as cell proliferation, survival, migration and invasion. Such mutations may be activating or inactivating and affect proto-oncogenes or tumour suppressor genes, respectively. It is becoming increasingly clear that, despite the accrual of advantageous mutations occurring specifically in the cancer cells, cells in the stroma can play a critical role in mediating tumour growth and progression. Therefore, although simple cell culture studies have given us amazing insight into the cell and molecular biology underpinning cancer cell behaviour, researchers are increasingly turning to more complex and physiologically relevant cell culture models, where more than one cell type is present, to better understand the nature of cancer.Ultimately, tumour metastasis is the major cause of death for cancer patients. It comprises the formation of secondary tumours by cells escaping from a primary tumour, circulating around the body (via lymph or blood) and becoming lodged at tissue-specific or non-specific sites some distance away [1]. Metastasis involves intimate interactions between cancer cells and their environment at a number of stages [2]. According to the classical 'seed and soil' model of metastasis, the primary tumour is biologically heterogeneous and only some cells gain metastatic ability late in tumourigenesis [3,4]. Furthermore, subpopulations of cells may have a tissue-specific expression profile, predetermining the site of metastasis [5]. However, for the purposes of this review, we have focused on the evolution of techniques to study the relatively early metastatic events. Before turning to these experimental models, we consider the main cell types and behaviours involved in tumour progression.Adhesive interactions between tumour cells and the surrounding substrata are pivotal to metastatic potential, with decreasing
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