Prevalence, intensity, and effect of a nematode (Philometra saltatrix) in the ovaries of bluefish (Pomatomus saltatrix)

Examination of 203 adult bluefish (Pomatomus saltatrix) from Long Island, New York, in 2002 and 2003 and 66 from the Outer Banks, North Carolina, in 2003 revealed the presence of dracunculoid nematodes (Philometra saltatrix) in the ovaries of female fish. Percent prevalence reached 88% in July and then decreased after the peak of the spawning season. Bluefish contained up to 100 parasites per fish. Infection was associated with a range of disorders, including hemorrhage, inf lammation, edema, prenecrotic and necrotic changes, and follicular atresia, that may prevent proper development of oocytes and probably affect bluefish fecundity. Historical occurrences, life cycle, and geographical distribution of this nematode remain largely unknown, but may play important roles in recruitment processes of bluefish

U.S. & International accounting : understanding the differences

https://egrove.olemiss.edu/aicpa_guides/1816/thumbnail.jp

Dark-Season Survival Strategies of Coastal Zone Zooplankton in the Canadian Arctic

For herbivorous zooplankton, surviving the arctic winter requires that sufficient energy be stored in summer to enable ten months or more of possible starvation. Energy and materials for reproduction may also be totally derived from stored lipid and bodily protein. The predominant storage products are wax esters, often visible as translucent droplets or a fusiform inclusion in the tissues. Lipid may constitute more than 50% of dry weight at the end of summer. Reproduction is synchronized with season and environmental conditions to enable offspring to exploit the brief period of intense primary production. So far as we know, fertilization occurs only once in the copepods studied here, which make up more than 98% of the total zooplankton by numbers, and males are short lived, but in one species (Calanus hyperboreus) females may survive into a second productive season, thereby storing sufficient reserves to spawn a second time. Several plaktonic species, including larval invertebrates, start growth early by utilizing algae that develop on the under-ice surface serveral months before the pelagic phytoplankton bloom. The minimum water temperature (-1.8 C) is constant and much warmer than the atmosphere, so overwintering should be less stressful for aquatic species than for terrestrial forms. Additional adaptations used by zooplankton in winter include seeking deeper water to escape predation, reducing swimming costs by regulating buoyancy, and further lowering metabolic rates by limiting synthesis of enzymes and increasing the fraction of lipid used in respiration.Key words: copepods, zooplankton, phytoplankton, ice-algae, fast ice, lipid, overwintering, survival strategies, growth, reproduction Afin de survivre à l'hiver arctique, le zooplancton herbivore doit stocker suffisamment d'énergie en été pour faire face à 10 mois ou plus de famine potentielle. Il se peut aussi que l'énergie et les matériaux servant à la reproduction soient tirés en totalité des lipides emmagasinés et des protéines du tissu corporel. Les produits stockés les plus importants sont les esters cireux, souvent visibles sous la forme de gouttelettes translucides ou d'une inclusion fusiforme dans les tissus. Les lipides peuvent constituer plus de 50 p. cent du poids sec à la fin de l'été. La reproduction est synchronisée avec les saisons et les conditions environnementales de façon à permettre à la progéniture de profiter de la courte période de production primaire intense. Dans l'état de nos connaissances actuelles, la fertilisation a lieu une seule fois chez les copépodes qui nous intéressent, et qui constituent plus de 98 p. cent du zooplancton total sur le plan numérique. Les mâles ont une durée de vie relativement courte, mais dans l'espèce Calanus hyperboreus, les femelles peuvent vivre assez longtemps pour entrer dans une deuxième phase de reproduction, stockant ainsi suffisamment de réserves pour frayer une seconde fois. Plusieurs espèces planctoniques, y compris des invertébrés larvaires, commencent à croître de bonne heure, en utilisant les algues qui se développent sur le dessous de la glace plusieurs mois avant la prolifération du phytoplancton pélagique. La température minimale de l'eau (-1,8 °C) est constante et beaucoup plus élevée que l'atmosphère, ce qui devrait rendre la survie hiémale moins stressante pour les espèces aquatiques que pour les formes terrestres. Parmi les autres adaptations utilisées par le zooplancton en hiver, on compte la recherche d'eaux plus profondes pour échapper aux prédateurs, la réduction du coût de la natation grâce à une régulation de la flottabilité, ainsi que la réduction du taux de métabolisme par une limite de la synthèse des enzymes et l'augmentation de la portion de lipides utilisés dans la respiration.Mots clés : copépodes, zooplancton, phytoplancton, algues glaciaires, banquise côtière, lipides, survie hiémale, stratégies de survie, croissance, reproductio

Assessing candidate preference through web browsing history

Predicting election outcomes is of considerable interest to candidates, political scientists, and the public at large. We propose the use of Web browsing history as a new indicator of candidate preference among the electorate, one that has potential to overcome a number of the drawbacks of election polls. However, there are a number of challenges that must be overcome to effectively use Web browsing for assessing candidate preference—including the lack of suitable ground truth data and the heterogeneity of user populations in time and space. We address these challenges, and show that the resulting methods can shed considerable light on the dynamics of voters’ candidate preferences in ways that are difficult to achieve using polls.Accepted manuscrip

High connectivity among locally adapted populations of a marine fish (Menidia menidia)

Author Posting. © Ecological Society of America, 2010. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecology 91 (2010): 3526–3537, doi:10.1890/09-0548.1.Patterns of connectivity are important in understanding the geographic scale of local adaptation in marine populations. While natural selection can lead to local adaptation, high connectivity can diminish the potential for such adaptation to occur. Connectivity, defined as the exchange of individuals among subpopulations, is presumed to be significant in most marine species due to life histories that include widely dispersive stages. However, evidence of local adaptation in marine species, such the Atlantic silverside, Menidia menidia, raises questions concerning the degree of connectivity. We examined geochemical signatures in the otoliths, or ear bones, of adult Atlantic silversides collected in 11 locations along the northeastern coast of the United States from New Jersey to Maine in 2004 and eight locations in 2005 using laser ablation inductively coupled plasma mass spectrometry (ICP-MS) and isotope ratio monitoring mass spectrometry (irm-MS). These signatures were then compared to baseline signatures of juvenile fish of known origin to determine natal origin of these adult fish. We then estimated migration distances and the degree of mixing from these data. In both years, fish generally had the highest probability of originating from the same location in which they were captured (0.01–0.80), but evidence of mixing throughout the sample area was present. Furthermore, adult M. menidia exhibit highly dispersive behavior with some fish migrating over 700 km. The probability of adult fish returning to natal areas differed between years, with the probability being, on average, 0.2 higher in the second year. These findings demonstrate that marine species with largely open populations are capable of local adaptation despite apparently high gene flow.This work was funded by the National Science Foundation (grant OCE-0425830 to D. O. Conover and grant OCE- 0134998 to S. R. Thorrold) and the New York State Department of Environmental Conservation

The Digital Evolution of Occupy Wall Street

We examine the temporal evolution of digital communication activity relating to the American anti-capitalist movement Occupy Wall Street. Using a high-volume sample from the microblogging site Twitter, we investigate changes in Occupy participant engagement, interests, and social connectivity over a fifteen month period starting three months prior to the movement's first protest action. The results of this analysis indicate that, on Twitter, the Occupy movement tended to elicit participation from a set of highly interconnected users with pre-existing interests in domestic politics and foreign social movements. These users, while highly vocal in the months immediately following the birth of the movement, appear to have lost interest in Occupy related communication over the remainder of the study period.Comment: Open access available at: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.006467

Partisan Asymmetries in Online Political Activity

We examine partisan differences in the behavior, communication patterns and social interactions of more than 18,000 politically-active Twitter users to produce evidence that points to changing levels of partisan engagement with the American online political landscape. Analysis of a network defined by the communication activity of these users in proximity to the 2010 midterm congressional elections reveals a highly segregated, well clustered partisan community structure. Using cluster membership as a high-fidelity (87% accuracy) proxy for political affiliation, we characterize a wide range of differences in the behavior, communication and social connectivity of left- and right-leaning Twitter users. We find that in contrast to the online political dynamics of the 2008 campaign, right-leaning Twitter users exhibit greater levels of political activity, a more tightly interconnected social structure, and a communication network topology that facilitates the rapid and broad dissemination of political information.Comment: 17 pages, 10 figures, 6 table

Portraits of Complex Networks

We propose a method for characterizing large complex networks by introducing a new matrix structure, unique for a given network, which encodes structural information; provides useful visualization, even for very large networks; and allows for rigorous statistical comparison between networks. Dynamic processes such as percolation can be visualized using animations. Applications to graph theory are discussed, as are generalizations to weighted networks, real-world network similarity testing, and applicability to the graph isomorphism problem.Comment: 6 pages, 9 figure

A Group-Based Yule Model for Bipartite Author-Paper Networks

This paper presents a novel model for author-paper networks, which is based on the assumption that authors are organized into groups and that, for each research topic, the number of papers published by a group is based on a success-breeds-success model. Collaboration between groups is modeled as random invitations from a group to an outside member. To analyze the model, a number of different metrics that can be obtained in author-paper networks were extracted. A simulation example shows that this model can effectively mimic the behavior of a real-world author-paper network, extracted from a collection of 900 journal papers in the field of complex networks.Comment: 13 pages (preprint format), 7 figure