1,721,353 research outputs found
Scanning a microhabitat: plant-microbe interactions revealed by confocal laser microscopy
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Shaking and stirring: Comparison of controlled laboratory stress conditions applied to the human growth hormone
No full textGastrocnemius medialis and vastus lateralis oxygenation during whole-body vibration exercise
No full textGastrocnemius Medialis and Vastus Lateralis Oxygenation during Whole-
Body Vibration Exercise. Med. Sci. Sports Exerc., Vol. 39, No. 4, pp. 694–700, 2007. Purpose: The aim of this study was to
investigate the effects of different whole-body vibration (WBV) frequencies on oxygenation of vastus lateralis (VL) and
gastrocnemius medialis (GM) muscles during static squatting in sedentary and physically active healthy males. Methods: Twenty
volunteers (age: 24.6 T 2.9 yr; body mass: 80.6 T 11.8 kg; height: 178.1 T 7.6 cm) participated in this study. Ten subjects were
sedentary individuals and 10 were athletes practicing different sports. All subjects completed four trials (control, and 30-, 40-, and
50-Hz WBV) in a randomized controlled crossover design. The trials consisted of static squatting on a vibrating platform for a total
duration of 110 s. Muscle-oxygenation status was recorded with near-infrared spectroscopy. Results: The data analysis revealed no
significant treatment-by-time interactions in tissue-oxygenation index (TOI) or $ total hemoglobin volume (tHb) in VL and GM
muscles. A significant main effect of time in TOI of both VL and GM muscles was identified (P G 0.001). VL TOI significantly
decreased by 2.8% at 90 s in the control condition and by 3.3% at 110 s in the 30-Hz condition; VL TOI significantly increased by 2.1
and 3.0% at 30 s in the 40- and 50-Hz conditions, respectively. GM TOI significantly decreased by 3.2% at 60 s, by 4.1% at 90 s, and
by 4.3% at 110 s in the control condition, and by 5.5% at 110 s in the 30-Hz condition. Conclusion: This study showed that WBV
exercise with frequencies of 30, 40, and 50 Hz and small amplitudes does not affect muscle oxygenation of VL and GM muscles to a
higher degree than a nonvibration condition
Feeding preferences of herring (Clupea harengus) and sprat (Sprattus sprattus) in the southern Baltic Sea
No full textNo field studies have been performed on the selectivity of herring and sprat in the southern
Baltic Sea in relation to their entire range of prey. Accordingly, we tested in the field the
following hypotheses: (i) sprat and herring are selective feeders and (ii) sprat and herring
selectivity is size- and season- dependent. The results show that (i) smaller herring and all
size classes of sprat are strictly zooplanktivorous, selecting principally Temora longicornis
and Bosmina maritima during the autumn and Pseudocalanus elongatus in winter; (ii)
larger herring are essentially nektobenthos feeders, predating on Mysis mixta during the
autumn and amphipods and polychaetes during the winter; and (iii) herring and sprat seem
to avoid Acartia spp. in both autumn and winter. During the autumn, herring are
zooplanktivorous up to 18e20 cm, whereas in winter herring feed on nektobenthos starting
from 14e15 cm. Selectivity was not an absolute process but it was related to prey relative
abundance in the sea and, possibly, to prey profitability (e.g. size, conspicuousness, and
reaction time)
Identification of the modal masses of an UAV structure in operational environment
No full textIn the framework of Operational Modal Analysis, several methods have been developed to estimate the modal parameters, that is natural frequencies, damping ratios, and mode shapes of a structure in its operative conditions. However, it is not possible to directly estimate the modal masses associated to each mode shape due to the unknown excitation. The modal masses are usually evaluated from the analysis of the change of the modal parameters by testing the structure in correspondence of two mass configurations. In this paper the efficiency and the accuracy of two procedures for the estimate of the modal masses are assessed by performing laboratory vibration tests. Vibration response data recorded during flight tests of an unmanned aerial vehicle (UAV) are used for this purpose as well as a mass changing device was developed to produce the mass variation of the structure. Results from the traditional input/output experimental modal analysis and the operational modal analysis are compared in terms of modal parameters, modal masses, and synthesized frequency response functions
Inter-annual variation in herring (Clupea harengus) and sprat (Sprattus sprattus) condition in the central Baltic Sea: what gives the tune?
No full textThe Baltic Sea ecosystem has undergone large changes during the last two decades, including a severe reduction in cod and herring biomass but, at the same time, a large increase in sprat abundance. The lower trophic levels of the Baltic Sea also changed due to environmental fluctuations, including variations in salinity and in volume of oxygenated water. In this apparently shifting environment, the conditions of herring and sprat have undergone large inter-annual variations during the past 15/20 years. In this study, we explore how abiotic factors (i.e. salinity and temperature) and biotic factors (biomass of the copepods Pseudocalanus elongatus, Temora longicornis, Acartia spp. and of cladocerans as well as clupeid abundance) in different seasons (May and August) affect clupeid body condition. Our analyses suggest that data of zooplankton biomass and abiotic factors in August have higher predictive power than May data. Although our analysis suggests that salinity (a bottom-up process) has an effect on sprat condition, total abundance of clupeids (a top-down process) is by far the most significant predictor of both herring and sprat condition. The strong correlation between clupeid abundance and total zooplankton biomass points to food competition and to top-down control by herring and sprat on common food resources. Furthermore, clupeid condition co-varied with the changes in the weight of zooplankton in the stomachs, which further suggest food competition being the main mechanism behind the changes in clupeid condition during the last two decades. Hence, our results are not in agreement with most of the current literature that has suggested that clupeid growth is regulated by environmentally mediated bottom-up processes acting on the abundance of copepods. This is, to our knowledge, the first evidence of food resources mediated density-dependent fish growth in a large marine ecosystem
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Disentangling the effect of adult biomass and temperature on the recruitment dynamics of fishes
No full textHere we analyzed the relation between recruitment dynamic (recruitment
or recruitment success) and temperature of 57 commercial fish
stocks of the North Atlantic. We showed that, although the effect of
temperature was generally significant, spawning biomass is the main
factor governing recruitment dynamic. A significant effect of spawning
biomass was evident for 67% of all stocks analyzed in this study. For
gadoids, the effect of spawning biomass was larger than the effect of
temperature (both in terms of number of stocks and proportion of variance
explained). For clupeids, spawning biomass was more important
than temperature for a higher number of stocks, but the strength of the
two effects, when present, was similar. Also, stocks living in colder and
warmer areas showed, respectively, a positive and negative response
to temperature for both families. Our results highlight that failing to
account for spawning biomass effect in climate-recruitment studies
could mask the influence of climate variability on recruitment dynamic.
In this context, although management of several exploited fish populations
cannot be entirely decoupled from the effect of climate on stock
reproductive success, it is likely that the observed changes in exploited
fish population dynamics are mainly the consequences of an unsustainable
human impact and not climate changes
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