939 research outputs found

    Baltic sprat larvae: coupling food availability, larval condition and survival

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    Eggs and larvae of Baltic sprat Sprattus sprattus L. were collected during 14 cruises covering the spawning season in 2002 in Bornholm Basin. Main egg and larval production was in April, with a second small peak in June 2002. The in situ larval abundance was corrected for transport processes by hydrodynamic model runs. Corrected larval abundance estimates were compared to initial larval production to derive an index of larval mortality. This index suggested a much higher survival of summer- over spring-born sprat larvae, with pronounced differences in survival for larvae >11 mm. Independent evidence for this survival pattern was gained by measured RNA:DNA ratios in sprat larvae hatched from April to July 2002 and was linked to temporal variability in potential prey abundance. We found higher mean but less variable RNA:DNA ratios in spring- than in summer-born larvae, indicating a strong selection for fast growth in April and May but a less selective environment in June and July. Zooplankton data revealed high naupliar concentrations of Acartia spp. (a key dietary component of sprat) in April and May, but very low concentrations of larger prey items such as copepodites or adults. In contrast, abundance of larger prey increased considerably in June and July. The results suggest that larger sprat (>11 mm) in April and May 2002 may have been food limited and, therefore, had lower rates of survival, supporting the underlying hypothesis of size-specific, temporally limited ‘windows of survival’ linked to the availability of suitable prey

    Employees, Firm Size and Profitability of U.S. Manufacturing Industries

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    We examine the relation between firm size and profitability within 109 SIC four-digit manufacturing industries. Depending on our measure of profitability, we find that profitability increases at a decreasing rate and eventually declines in up to 47 of our industries. No relation between profitability and size is found in up to 52 of our industries. These two categories account for 97 of our 109 industries. Profitability continues to increase as firms become larger in up to 11 industries. Hence, the relation between size and profitability is industry specific. But, regardless of the shape of the size profitability function, we find that profitability is negatively correlated with the number of employees for firms of a given size measured in terms of total assets and sales. These results are puzzling in the context of work by others who report that common stock returns are negatively correlated with size when size is measured by the market value of a company or with the work of those who argue that size is a proxy for risk. Interpreted against these works, our findings may mean that large firms earn excess returns, that small firms fail to earn their cost of capital, or that accounting returns simply behave differently than market returns with respect to firm size

    Acoustic behavior of melon-headed whales varies on a diel cycle.

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    Many terrestrial and marine species have a diel activity pattern, and their acoustic signaling follows their current behavioral state. Whistles and echolocation clicks on long-term recordings produced by melon-headed whales (Peponocephala electra) at Palmyra Atoll indicated that these signals were used selectively during different phases of the day, strengthening the idea of nighttime foraging and daytime resting with afternoon socializing for this species. Spectral features of their echolocation clicks changed from day to night, shifting the median center frequency up. Additionally, click received levels increased with increasing ambient noise during both day and night. Ambient noise over a wide frequency band was on average higher at night. The diel adjustment of click features might be a reaction to acoustic masking caused by these nighttime sounds. Similar adaptations have been documented for numerous taxa in response to noise. Or it could be, unrelated, an increase in biosonar source levels and with it a shift in center frequency to enhance detection distances during foraging at night. Call modifications in intensity, directionality, frequency, and duration according to echolocation task are well established for bats. This finding indicates that melon-headed whales have flexibility in their acoustic behavior, and they collectively and repeatedly adapt their signals from day- to nighttime circumstances

    Die Potentiale von e-business in der Wertschöpfungskette

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    Unsere Gesellschaft macht sich auf den Weg zur sogenannten Informationsgesellschaft. Im ökonomischen Bereich zeigt sich dieser Trend durch die verstĂ€rkte Anwendung von Internet-Technologien. Der Trend der letzten Jahre zeigt deutlich, daß die Verbreitung des Internet und deren wirtschaftliche Nutzung nicht mehr aufzuhalten sind. Wir befinden uns inmitten einer tiefgreifenden Umgestaltung des wirtschaftlichen Lebens. Dieser Entwicklung können sich auch Unternehmen nicht entziehen. Das Internet und die damit verbundenen Anwendungen bringen bei einem immer stĂ€rker werdenden Wettbewerbs- und Kostendruck Chancen mit sich, UnternehmensablĂ€ufe neu zu gestalten, um sich so von Konkurrenten zu differenzieren und somit Wettbewerbsvorteilen zu erzielen. Integrierte Informationssysteme, die mit Hilfe des Internet arbeiten, machen es möglich, die Wertschöpfungskette zwischen Angestellten, Kunden, Lieferanten und HĂ€ndlern neu zu gestalten und somit Kosten zu sparen, kundenfreundlich zu agieren und fĂŒr alle Beteiligten Vorteile zu erzielen. Das weitreichende Potential des Internet ermöglicht gar eine komplette Neustrukturierung der Wertschöpfungskette eines Unternehmens und hat somit Auswirkungen auf alle Unternehmensbereiche. Die klassischen Grenzen der Unternehmung beginnen sich nach innen wie nach außen zu verĂ€ndern, teilweise auch aufzulösen. Viele Unternehmen nutzen die Potentiale des Internet jedoch nur in Teilbereichen und schöpfen nicht das gesamte Spektrum der Möglichkeiten aus. Insbesondere die internen Wertschöpfungsprozesse, die große Chancen beinhalten, werden hĂ€ufig vernachlĂ€ssigt

    Simulation of rotating drum experiments using non-circular particles

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    We investigate the flow of granular material in a rotating cylinder numerically using molecular dynamics in two dimensions. The particles are described by a new model which allows to simulate geometrically complicated shaped grains. The results of the simulation agree significantly better with experiments than the results which are based on circular particles.Comment: 15 pages, 9 figure

    Cisplatin-Based Chemotherapy for Pulmonary Metastasized Germ Cell Tumors of the Testis - Be Aware of Acute Respiratory Distress Syndrome

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    Background: Cisplatin-based combination chemotherapy is regarded as standard of care for patients with advanced germ cell tumors. In patients with lung metastases and a high tumor load, an association between induction chemotherapy and the development of a `tumor-associated' acute respiratory distress syndrome (ARDS) has been hypothesized. Case Report: We report the clinical course of a 19-year-old patient who rapidly developed fatal ARDS during the first cycle of chemotherapy using the PEI regimen (cisplatin, etoposide and ifosfamide) for a metastasized (lung, liver, lymph nodes) germ cell tumor of the testis. Conclusion: Further clinical research in order to better define risk factors for developing ARDS in this patient population as well as novel strategies for the prevention and treatment of ARDS in those patients are necessary

    Astheure und maintenant im Französischen Nordamerikas im Vergleich: Eine korpusbasierte Untersuchung

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    Der Aufsatz untersucht die Verwendung der beiden französischen Temporal­adverbien astheure und maintenant im Französischen Nordamerikas. Aufbauend auf einer Analyse von WörterbucheintrÀgen zum Adverb astheure wird zunÀchst dessen Verbreitung in Frankreich und Nordamerika aufgezeigt, wo astheure weitaus gebrÀuchlicher ist als in Frankreich selbst. Im zweiten Teil des Aufsatzes wird die Verwendung von astheure im Vergleich zu maintenant anhand einer Korpusuntersuchung analysiert, die auf den drei Korpora FRAN, Varitext und CFPQ basiert. Dabei wird ersichtlich, dass sich die beiden Adverbien zwar weitgehend als synonym erweisen, hinsichtlich ihres variationellen Status jedoch stark voneinander unterscheiden: WÀhrend sich maintenant in allen VarietÀten belegen lÀsst, erweist sich astheure im Französischen Nordamerikas als ein Element der NÀhesprache.The article examines the use of the French temporal adverbs astheure and maintenant in the French-speaking part of North America. Based on an analysis of dictionary entries of the adverb astheure, the article initially describes its distribution in France and North America, where astheure is by far more often used than in France. The second part of the article compares the usage of astheure and maintenant in North America on the basis of a corpus study. This study, which is based on the three corpora FRAN, Varitext and CFPQ, clearly shows that the two adverbs can largely be seen as synonyms, but that there is an important difference with regard to their variational status: Whereas maintenant is used in all varieties, astheure proves to be an element of the language of proximity in North American French

    Cell type-specific expression of endogenous cardiac Troponin I antisense RNA in the neonatal rat heart

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    Since the number of detected natural antisense RNA is growing, investigations upon the expression pattern of the antisense RNA become more important. As we focused our work on natural occurring antisense transcripts in human and rat heart tissues, we were interested in the question, whether the expression pattern of antisense and sense RNA can vary in different cell types of the same tissue. In our previous analysis of total neonatal rat heart tissue, we demonstrated the co-expression of both cTnI RNA species in this tissue. Now we investigated the expression of antisense and sense RNA quantitatively in neonatal cardiomyocytes (NCMs) and neonatal cardiac fibroblasts (NCFs). Performing northern blot as well as RT-PCR, we could detect natural antisense and sense RNA transcripts of cTnI in NCM and NCF implying that these transcripts are co-expressed in both cell types. The absolute amounts of the RNA transcripts were higher in NCM. Both RNA species showed identical sizes in the northern blot. Quantification by real-time PCR revealed a higher relative level of natural antisense RNA in NCF compared to NCM which points out to a cell type-specific expression of sense and antisense RNA. Our observations suggest that antisense RNA transcription may contribute to a cell type-specific regulation of the cTnI gen

    Detection of 133^{133}Xe from the Fukushima nuclear power plant in the upper troposphere above Germany

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    After the accident in the Japanese Fukushima Dai-ichi nuclear power plant in March 2011 large amounts of radioactivity were released and distributed in the atmosphere. Among them were also radioactive noble gas isotopes which can be used as tracers to test global atmospheric circulation models. This work presents unique measurements of the radionuclide 133^{133}Xe from Fukushima in the upper troposphere above Germany. The measurements involve air sampling in a research jet aircraft followed by chromatographic xenon extraction and ultra-low background gas counting with miniaturized proportional counters. With this technique a detection limit of the order of 100 133^{133}Xe atoms in litre-scale air samples (corresponding to about 100 mBq/m3^3) is achievable. Our results provide proof that the 133^{133}Xe-rich ground level air layer from Fukushima was lifted up to the tropopause and distributed hemispherically. Moreover, comparisons with ground level air measurements indicate that the arrival of the radioactive plume at high altitude over Germany occurred several days before the ground level plume.Comment: 8 pages, 5 figure

    A new Retention Index for the Central Baltic Sea: Long-Term Hydrodynamic Modelling Used to Improve Baltic Sprat, Sprattus sprattus, Recruitment Models

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    To study inter-annual differences in drift patterns of larval sprat from the Bornholm Basin, we used a 3D, eddy-resolving circulation model of the Baltic Sea and simulated the drift of Lagrangian particles for each of 24 years (1979-2002) of available forcing data. We observed that in some years particles were transported almost completely out of the basin, whereas circulation in other years retained the majority of drifters within the seeding area (Bornholm Basin). A new retention index was derived that is associated to age 0 sprat recruitment in ICES Subdivision 25, estimated from area-disaggregated MSVPA runs. The significant linear relationship (P 80%) than those derived from particles released earlier into the model domain. This intra-annual pattern may suggest that recruitment success in central Baltic sprat was – at least during the last decade - predominantly determined by the relative survival of larval cohorts emerging late in the spawning season. The index is significantly cross-correlated to other environmental time series, most importantly annual surface temperature in August, which makes it difficult to conclude on the processes crucial for central Baltic sprat recruitment success
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