1,721,095 research outputs found
Variational convergence of nonlinear diffusion equations: applications to concentrated capacity problems with change of phase
No full textWe study a variational formulation for a Stefan problem in two adjoining bodies, when the heat conductivity of one of them becomes infinitely large. We study the `concentrated capacity' model arising in the limit, and we justify it by an asymptotic analysis, which is developed in the general framework of abstract evolution equations of monotone type
Abundance of Rock Partridge (Alectoris graeca) in relation to the multi spatial structure of habitat and food availability.
Full text linkIn the Prealpi Giulie Natural Park the distribution and abundance of the Rock Partridge Alectoris graeca saxatilis have been studied in 5 sample areas using the play-back technique, and related to habitat availability (Vegetation Map of the park, 1:25.000) at different spatial scales. The UTM 1x1 kilometer regional grid has been used for a large scale approach, assigning the number of partridges counted to each quadrant. The mean geo-morphological aspects, the herbaceous and shrub vegetation characteristics (density, height, colour, etc), the abundance of insects (pitfall traps), and management applied on the area (pasture, mowing, etc) have also been measured for each quadrant. Buffer surfaces of 500 and 100 meters of radius from the detection-points of the animals have been used respectively as medium and small scale approaches and compared to randomly selected buffer areas. GIS analysis has been carried out to determine habitat coverage in each quadrant and buffer. Different parameters seem to describe properly the ecological requirements of this species in the study area. Its abundance was correlated at all scales to grasslands widely colonized by Genista radiata. This element, together with high herbaceous vegetation at large scales, could provide shelter from flying predators. At medium to small scales species-rich mesophile hay meadows seem to enhance the presence of Rock Partridges, locally providing a large stock of food resources and together with xeric grasslands representing the optimal mixture of habitats for this phasianid. In contrast pastures colonized by shrubs and trees (high density, large diameter) seem to have a negative effect on the species presence at large to small scales. This multiscale approach allows to detect more appropriately the ecological requirements of this animal
Relation between parasites, reproductive index and habitat change in Rock Partridge (Alectoris graeca) populations in the central Southern Alps.
Full text linkRelation between parasites, reproductive index and habitat change in
Rock Partridge (Alectoris graeca) populations in the central southern
alps.
FABRO C.1, VISINTIN A.1, FILACORDA S.1, FRANGIPANE DI REGALBONO A.2, ARTUSO I.3
1Department of Agriculture and Environmental Sciences – University of Udine
2Department of Experimental Veterinary Science- University of Padua
3Comprensorio Alpino N°1 Val Brembana Hunting district
Within the hunting district of Val Brembana the presence of parasites along the intestinal tract
in 60 individuals (32 adults and 22 juveniles, 6 indeterminate) has been studied and correlated
to the reproductive indexes (R.I, measured on 3 and 6 years) of Rock Partridges Alectoris graeca
saxatilis in 6 different sectors and the habitat change. Within these sectors the coverage (%) of
several environmental classes in different sample areas has been identified through photo
interpretation over a time interval of 25 years. In the whole area a high spread of the nematode
Ascaridia was observed and high values of prevalence (P = 69.49%) and mean abundance (MA
= 15.21) have been found, while the presence of genus Capillaria was low with MA = 0.17 and P
= 13.56%. Heterakis was isolated in 33.90% of the Rock Partridges, with MA = 1.45. For Ascaridia
and Heterakis the relationship between variance and mean abundance (s2/MA) was
significantly greater than one (Ascarids = 48.94; Heterakis: 7.90) and the aggregation index k (s2
/ (s2-MA) ) was very close to zero, proving that these parasites show a highly aggregated
distribution within host populations. When analyzing separately the 2 age classes there
seemed to be no significant difference in parasitic infection susceptibility between juveniles (P
= 95.45%) and adults (P = 84.95%). Only MA and P of Heterakis in different sectors was
negatively correlated to a change in reproductive success, both in short and medium term,
while the sectors with the greatest MA of Ascaridia, both in short and medium term, showed
the highest mean reproductive rates and the sectors with the highest k of Capillaria had the
highest R.I. The presence of parasites and particularly the value of MA of Capillaria and the
average total number of parasites seemed to increase with the decreasing of open areas
(coverage) in the different sectors of the study area, as well as with the decreasing of this
observed coverage throughout the 25 year period. A negative correlation between open areas
and the s2/AM ratio was discovered to be very clear. The presence of open areas seemed to
affect significantly the abundance of parasites that in turn seemed to only partially drive R.I
changes. The research was supported by Comprensorio Alpino N° 1 Val Brembana Hunting
district
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
Targeted therapy of solid malignancies via HLA class II antigens: a new biotherapeutic approach?
No full textVariations 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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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