682 resultados para Atkinson
Resumo:
ABSTRACT: The ability of Antarctic krill Euphausia superba Dana to withstand the overwintering period is critical to their success. Laboratory evidence suggests that krill may shrink in body length during this time in response to the low availability of food. Nevertheless, verification that krill can shrink in the natural environment is lacking because winter data are difficult to obtain. One of the few sources of winter krill population data is from commercial vessels. We examined length-frequency data of adult krill (>35 mm total body length) obtained from commercial vessels in the Scotia-Weddell region and compared our results with those obtained from a combination of science and commercial sampling operations carried out in this region at other times of the year. Our analyses revealed body-length shrinkage in adult females but not males during overwinter, based on both the tracking of modal size classes over seasons and sex-ratio patterns. Other explanatory factors, such as differential mortality, immigration and emigration, could not explain the observed differences. The same pattern was also observed at South Georgia and in the Western Antarctic Peninsula. Fitted seasonally modulated von Bertalanffy growth functions predicted a pattern of overwintering shrinkage in all body-length classes of females, but only stagnation in growth in males. This shrinkage most likely reflects morphometric changes resulting from the contraction of the ovaries and is not necessarily an outcome of winter hardship. The sex-dependent changes that we observed need to be incorporated into life cycle and population dynamic models of this species, particularly those used in managing the fishery. KEY WORDS: Southern Ocean · Population dynamics · Production · Life cycle · Fishery
Resumo:
Growing evidence has shown a profound modification of plankton communities of the North East Atlantic and adjacent seas over the past decades. This drastic change has been attributed to a modification of the environmental conditions that regulate the dynamics and the spatial distribution of ectothermic species in the ocean. Recently, several studies have highlighted modifications of the regional climate station L4 (50° 15.00′N, 4° 13.02′W) in the Western English Channel. We here focus on the modification of the plankton community by studying the long-term, annual and seasonal changes of five zooplankton groups and eight copepod genera. We detail the main composition and the phenology of the plankton communities during four climatic periods identified at the L4 station: 1988–1994, 1995–2000, 2001–2007 and 2008–2012. Our results show that long-term environmental changes underlined by Molinero et al. (2013) drive a profound restructuration of the plankton community modifying the phenology and the dominance of key planktonic groups including fish larvae. Consequently, the slow but deep modifications detected in the plankton community highlight a climate driven ecosystem shift in the Western English Channel.
Resumo:
Growing evidence has shown a profound modification of plankton communities of the North East Atlantic and adjacent seas over the past decades. This drastic change has been attributed to a modification of the environmental conditions that regulate the dynamics and the spatial distribution of ectothermic species in the ocean. Recently, several studies have highlighted modifications of the regional climate station L4 (50° 15.00′N, 4° 13.02′W) in the Western English Channel. We here focus on the modification of the plankton community by studying the long-term, annual and seasonal changes of five zooplankton groups and eight copepod genera. We detail the main composition and the phenology of the plankton communities during four climatic periods identified at the L4 station: 1988–1994, 1995–2000, 2001–2007 and 2008–2012. Our results show that long-term environmental changes underlined by Molinero et al. (2013) drive a profound restructuration of the plankton community modifying the phenology and the dominance of key planktonic groups including fish larvae. Consequently, the slow but deep modifications detected in the plankton community highlight a climate driven ecosystem shift in the Western English Channel.
Resumo:
Quintus Curtius found in his sources a speech where a Scythian censured Alexander, followed by the King’s reply. Curtius drastically abridged this second discourse in order to highlight the criticism of the Macedonian. The Scythian’s words have a striking rhetorical language and some allusions taken from Greek literature, in addition to possible indirect references to Caligula. Curtius declares that he follows his source word-for-word aiming to justify these inconsistencies, but also trying to hide the manipulations he has done to achieve his own narrative purposes.
Resumo:
Deeply conflicting views on the political situation of Judaea under the Roman prefects (6-41 c.e.) have been offered. According to some scholars, this was a period of persistent political unrest and agitation, whilst according to a widespread view it was a quiescent period of political calm (reflected in Tacitus’ phrase sub Tiberio quies). The present article critically examines again the main available sources –particularly Josephus, the canonical Gospels and Tacitus– in order to offer a more reliable historical reconstruction. The conclusions drawn by this survey calls into question some widespread and insufficiently nuanced views on the period. This, in turn, allows a reflection on the non-epistemic factors which might contribute to explain the origin of such views.
Resumo:
Recent proxy measurements reveal that subglacial lakes beneath modern ice sheets periodically store and release large volumes of water, providing an important but poorly understood influence on contemporary ice dynamics and mass balance. This is because direct observations of how lake drainage initiates and proceeds are lacking. Here we present physical evidence of the mechanism and geometry of lake drainage from the discovery of relict subglacial lakes formed during the last glaciation in Canada. These palaeo-subglacial lakes comprised shallow (<10 m) lenses of water perched behind ridges orientated transverse to ice flow. We show that lakes periodically drained through channels incised into bed substrate (canals). Canals sometimes trend into eskers that represent the depositional imprint of the last high-magnitude lake outburst. The subglacial lakes and channels are preserved on top of glacial lineations, indicating long-term re-organization of the subglacial drainage system and coupling to ice flow.
Resumo:
FMRFamide-like peptide (FLP) signalling systems are core to nematode neuromuscular function. Novel drug discovery efforts associated with nematode FLP/FLP receptor biology are advanced through the accumulation of basic biological data that can reveal subtle complexities within the neuropeptidergic system. This study reports the characterisation of FMRFamide-like peptide encoding gene-11 (flp-11) and FMRFamide-like peptide encoding gene-32 (flp-32), two distinct flp genes which encode the analogous peptide, AMRN(A/S)LVRFamide, in multiple nematode species - the only known example of this phenomenon within the FLPergic system of nematodes. Using bioinformatics, in situ hybridisation, immunocytochemistry and behavioural assays we show that: (i) flp-11 and -32 are distinct flp genes expressed individually or in tandem across multiple nematode species, where they encode a highly similar peptide; (ii) flp-11 does not appear to be the most widely expressed flp in Caenorhabditis elegans; (iii) in species expressing both flp-11 and flp-32, flp-11 displays a conserved, restricted expression pattern across nematode clades and lifestyles; (iv) in species expressing both flp-11 and flp-32, flp-32 expression is more widespread and less conserved than flp-11; (v) in species expressing only flp-11, the flp-11 expression profile is more similar to the flp-32 profile observed in species expressing both; and (vi) FLP-11 peptides inhibit motor function in multiple nematode species. The biological significance and evolutionary origin of flp-11 and -32 peptide duplication remains unclear despite attempts to identify a common ancestor; this may become clearer as the availability of genomic data improves. This work provides insight into the complexity of the neuropeptidergic system in nematodes, and begins to examine how nematodes may compensate for structural neuronal simplicity. From a parasite control standpoint this work underscores the importance of basic biological data, and has wider implications for the utility of C. elegans as a model for parasite neurobiology.
Resumo:
Case study research has the advantage of investigating issues that are embedded within the context of the case. A novel approach to investigation of the implementation of service innovation process has been adopted through a longitudinal ethnographic case study. This approach was found useful, as the outcome of the study was intended to be an in-depth understanding of firm’s current innovation practices and its consequences with the implementation of a novel business process. In this applied research, an array of longitudinal data was generated chiefly through the technique of participant-observation. Participant-observation as a qualitative or naturalistic method has its roots in ethnographic research. Participant-observation involves “participating in the social world, in whatever role, and reflecting on the products of that participation” (Hammersley & Atkinson, 1983, p.16). This method offers a degree of understanding of the context under study that can come only from personal experience. In this presentation, I discuss the role of the researcher-practitioner as participant-observer and the usefulness of ethnographic case study methodology and participant-observation technique to investigating service innovation practices that are embedded within the context-specific setting of the case.
Resumo:
Recent advances in the massively parallel computational abilities of graphical processing units (GPUs) have increased their use for general purpose computation, as companies look to take advantage of big data processing techniques. This has given rise to the potential for malicious software targeting GPUs, which is of interest to forensic investigators examining the operation of software. The ability to carry out reverse-engineering of software is of great importance within the security and forensics elds, particularly when investigating malicious software or carrying out forensic analysis following a successful security breach. Due to the complexity of the Nvidia CUDA (Compute Uni ed Device Architecture) framework, it is not clear how best to approach the reverse engineering of a piece of CUDA software. We carry out a review of the di erent binary output formats which may be encountered from the CUDA compiler, and their implications on reverse engineering. We then demonstrate the process of carrying out disassembly of an example CUDA application, to establish the various techniques available to forensic investigators carrying out black-box disassembly and reverse engineering of CUDA binaries. We show that the Nvidia compiler, using default settings, leaks useful information. Finally, we demonstrate techniques to better protect intellectual property in CUDA algorithm implementations from reverse engineering.
Resumo:
The Internet of things (IoT) is still in its infancy and has attracted much interest in many industrial sectors including medical fields, logistics tracking, smart cities and automobiles. However, as a paradigm, it is susceptible to a range of significant intrusion threats. This paper presents a threat analysis of the IoT and uses an Artificial Neural Network (ANN) to combat these threats. A multi-level perceptron, a type of supervised ANN, is trained using internet packet traces, then is assessed on its ability to thwart Distributed Denial of Service (DDoS/DoS) attacks. This paper focuses on the classification of normal and threat patterns on an IoT Network. The ANN procedure is validated against a simulated IoT network. The experimental results demonstrate 99.4% accuracy and can successfully detect various DDoS/DoS attacks.
Resumo:
Since 1993 Atlantic menhaden has experienced sustained low juvenile production (recruitment) in the Chesapeake Bay. Factors controlling growth, abundance, and mortality of larval and juvenile menhaden change throughout ontogeny such that larval growth rates could carry over to juvenile growth and survival. The effects of winter thermal conditions on the hatch dates and growth of larval and juvenile Atlantic menhaden in Atlantic shelf and Chesapeake Bay habitats were examined using otolith (ear-stone) increment analyses and growth models. For 2010-2013, truncated hatch-date distributions provided evidence for a winter recruitment bottleneck in Atlantic menhaden caused by cold temperatures. Hatch-dates of surviving juveniles were skewed towards warmer months for years characterized by colder temperatures. Reduced larval growth rates, influenced by reduced temperature and food availability, carried over to juvenile growth rates. A growing degree-day model performed well in simulating observed juvenile growth rates in the Choptank River tributary of Chesapeake Bay.
Resumo:
Shows buildings, plantings, and the Ellipse.
Resumo:
Developing Cyber-Physical Systems requires methods and tools to support simulation and verification of hybrid (both continuous and discrete) models. The Acumen modeling and simulation language is an open source testbed for exploring the design space of what rigorousbut- practical next-generation tools can deliver to developers of Cyber- Physical Systems. Like verification tools, a design goal for Acumen is to provide rigorous results. Like simulation tools, it aims to be intuitive, practical, and scalable. However, it is far from evident whether these two goals can be achieved simultaneously. This paper explains the primary design goals for Acumen, the core challenges that must be addressed in order to achieve these goals, the “agile research method” taken by the project, the steps taken to realize these goals, the key lessons learned, and the emerging language design.
Resumo:
El objetivo fundamental de la investigación es demostrar que la representación teatral es una técnica didáctica válida y eficaz para la enseñanza gramatical de contenidos asociados al texto dialógico en ELE. Se introducen los conceptos de dramatización y representación como técnicas didácticas, así como el desarrollo del texto teatral sin representación en ELE en función de sus características y diferencias para favorecer el desarrollo de competencias y subcompetencias (como la comprensión lectora y la expresión escrita, gramatical y léxica, etc.) . En este marco teórico se presentan las dimensiones teatral, no verbal y lingüística del texto dialógico con una amplia base de estudios e investigaciones: Vygotski (1934) en cuanto al aprendizaje significativo e influencia en la memoria, y las reflexiones de Atkinson y Shiffrin (1968), Craik y Lockhart (1972), Tulving (1982), Squire (1986, 1987), Badeley (1990) y Forgas (1995) en referencia a los tipos de memoria y su vinculación en el aprendizaje. Se analizan varios estudios asociados a las teorías teatrales de Eines (2005, 2008, 2011, 2015), Richards (2005), Grotwski (1976), y Stanivslaski (1924, 1937, 1951) en relación con el análisis y reforzamiento del texto dialógico aplicado en ELE. En cuanto a la perspectiva pragmática en relación a los actos de habla y la comunicación no verbal se recurre a Hall (1966), Davis (1976) Asher (1969), Fischer- Lichte (1999), Austin (1962), Grice (1975) y Ubersfeld (1989). Por último, se analizaron las conexiones de la competencia comunicativa según las teorías de Chomsky (1955, 1957), Hymes (1962, 1964) y Widdowson (1995) con la representación teatral como técnica didáctica y se desarrolla la esfera psicolingüística que se potencia con dicha técnica según las teorías de Titone (1995), Rabault (2011), Koryakina (2013) y Petrovna Fesenko (2013). Conceptos teatrales relacionados con la disciplina piscolingüística son analizados gracias a los estudios de Pit Corder (1973), Finocchiaro y Brumfin (1983), Linell (1985) –cit. por Torres Núñez, 1996- y Torres Núñez (1996). En la parte experimental se desarrolla un diagnóstico previo para dilucidar las dificultades gramaticales más altas del texto dialógico en una muestra de 107 alumnos sinohablantes. Posteriormente se comprueba si el tratamiento en base a la representación como técnica didáctica tiene efecto en un Grupo de Control y un Grupo Experimental. Se seleccionan cinco de las categorías que suponen un mayor número de errores en el diagnóstico previo para el diseño experimental: Usos del Presente de Indicativo, Formas Reflexivas y Pronominales, Selección Léxica, Pretérito Perfecto Compuesto y Pretérito Imperfecto. El análisis estadístico revela que el tratamiento influyó significativamente en el descenso de errores en los alumnos del GE. Las conclusiones derivadas de la investigación permiten demostrar que la representación como técnica didáctica es un recurso válido en cuanto a la enseñanza- aprendizaje de contenidos gramaticales asociados al texto dialógico en ELE como técnica que integra todas las destrezas planteadas por el Marco Común Europeo de Referencia para las Lenguas y favorece el desarrollo de las competencias implicadas en el texto dialógico y establecidas en el Plan Curricular del Instituto Cervantes.
Resumo:
The goal of this project is to increase the amount of successful real estate license renewals while reducing the disruption caused by manual processing and calls for assistance with renewals and technical issues. The data utilized in this project will demonstrate that the Real Estate Commission renewal process can be improved by utilizing electronic resources such as more detailed website information and repeat e-mail notices, through modifications to the online renewal process to reduce applicant error, and by increasing the visibility of online renewal log-in instructions while decreasing the visibility and use of mail-in applications.