112 research outputs found
Frontal White Matter Volume Is Associated with Brain Enlargement and Higher Structural Connectivity in Anthropoid Primates
Previous research has indicated the importance of the frontal lobe and its ‘executive’ connections to other brain structures as crucial in explaining primate neocortical adaptations. However, a representative sample of volumetric measurements of frontal connective tissue (white matter) has not been available. In this study, we present new volumetric measurements of white and grey matter in the frontal and non-frontal neocortical lobes from 18 anthropoid species. We analyze this data in the context of existing theories of neocortex, frontal lobe and white versus grey matter hyperscaling. Results indicate that the ‘universal scaling law’ of neocortical white to grey matter applies separately for frontal and non-frontal lobes; that hyperscaling of both neocortex and frontal lobe to rest of brain is mainly due to frontal white matter; and that changes in frontal (but not non-frontal) white matter volume are associated with changes in rest of brain and basal ganglia, a group of subcortical nuclei functionally linked to ‘executive control’. Results suggest a central role for frontal white matter in explaining neocortex and frontal lobe hyperscaling, brain size variation and higher neural structural connectivity in anthropoids
Georeferenced digital photography for an objective and reproducible quantification of staging sea birds
Ein Ausbau der Windenergienutzung auf See könnte zu einem
deutlichen Verlust an störungsfreien Überwinterungs- und
Rastgebieten für Seevögel führen. Um die Auswirkungen von
Windparks vor, während und nach ihrem Bau einschätzen zu
können, werden im derzeitigen Standarduntersuchungskonzept
des Bundesamtes für Seeschifffahrt und Hydrographie
(BSH) neben schiffs- auch flugzeugbasierte Vogelzählungen
empfohlen. Diese visuellen Transektzählungen haben jedoch
methodische Nachteile. Aus der zur Arterkennung erforderlichen
Flughöhe (78 m) und mit entsprechender Fluggeschwindigkeit
können bei hohem Vogelaufkommen lediglich
grobe Bestandskategorien geschätzt werden. Darüber hinaus
üben Flugzeuge in dieser Höhe eine Scheuchwirkung auf
Rastvögel aus, wodurch die Erfassbarkeit einiger Arten (v. a.
Trauerenten) zusätzlich erschwert und die zu untersuchende
Störwirkung von Windparks überlagert wird. In der vorliegenden
Pilotstudie vergleichen wir eine herkömmliche Flugzeugtransektzählung
mit einer kurz zuvor durchgeführten
fotografischen Seevogelerfassung über der Wismarbucht in
der deutschen Ostsee. Die fotografische Kartierung erfolgte
mit einer hoch auflösenden Digitalkamera (39 Megapixel) aus
200 m Höhe. Entlang definierter Transekte wurden in regelmäßigen
Abständen 415 entzerrte, maßstabsgetreue Digitalfotos
(Orthofotos) aufgenommen. Die Ergebnisse dieser
Studie zeigen, dass bei der herkömmlichen Flugzeugtransektzählung
die Bestände von Meeresenten (Eider-, Eis-, Trauerenten)
deutlich unterschätzt wurden. Die Abweichung gegenüber
der fotografischen Methode variierte deutlich zwischen
den Arten. Während des visuellen Zählflugs wurden ohne
Korrekturfaktoren 85 % (Eiderente), 41 % (Eisente) und lediglich
2 % (Trauerente) der fotografisch nachgewiesenen Individuen
erfasst. Die Ursachen für diese quantitativen Unterschiede
werden diskutiert.An expansion of offshore wind energy production could lead to a significant loss of wintering and staging habitats for seabirds.
To assess the impact of wind farms before, during and after their construction, the standard investigation concept of the
Federal Maritime and Hydrographic Agency (BSH) currently recommends ship- and aircraft-based bird surveys. Observationbased
aerial surveys, however, have methodological disadvantages: Low flight elevation (78 m), necessary for species recognition,
and high flight speed in combination with large numbers of birds allow only rough population estimates. In addition,
aircrafts flying at this elevation disturb resting birds, further obstructing their quantification. In this pilot study, we compared
visually estimated seabird numbers collected during an aerial transect survey with numbers derived from digital aerial photographs
of the same transects. The photographic survey was carried out shortly before the visual survey at a height of 200 m
above sea level using a high-resolution digital camera (39 Mega pixels). 415 vertical photos corrected for geometry and scale
were taken at regular intervals along defined transects. The results of this study suggest that the observational survey significantly
underestimated the number of sea ducks. The difference between visual and photographic methods varied considerably
among species: 85% (Common Eider, Somateria mollissima), 41% (Long-tailed Duck, Clangula hyemalis) and only 2% (Common
Scoter, Melanitta nigra) of the photographically documented individuals were observed. The reasons for these quantitative
differences are discussed
Influence of Deceased Donor and Pretransplant Recipient Parameters on Early Overall Kidney Graft-Survival in Germany
Background. Scarcity of grafts for kidney transplantation (KTX) caused an increased consideration of deceased donors with substantial risk factors. There is no agreement on which ones are detrimental for overall graft-survival. Therefore, we investigated in a nationwide multicentre study the impact of donor and recipient related risks known before KTX on graft-survival based on the original data used for allocation and graft acceptance. Methods. A nationwide deidentified multicenter study-database was created of data concerning kidneys donated and transplanted in Germany between 2006 and 2008 as provided by the national organ procurement organization (Deutsche Stiftung Organtransplantation) and BQS Institute. Multiple Cox regression (significance level 5%, hazard ratio [95% CI]) was conducted (n=4411, isolated KTX). Results. Risk factors associated with graft-survival were donor age (1.020 [1.013–1.027] per year), donor size (0.985 [0.977–0.993] per cm), donor’s creatinine at admission (1.002 [1.001–1.004] per µmol/L), donor treatment with catecholamine (0.757 [0.635–0.901]), and reduced graft-quality at procurement (1.549 [1.217–1.973]), as well as recipient age (1.012 [1.003–1.021] per year), actual panel reactive antibodies (1.007 [1.002–1.011] per percent), retransplantation (1.850 [1.484–2.306]), recipient’s cardiovascular comorbidity (1.436 [1.212–1.701]), and use of IL2-receptor antibodies for induction (0.741 [0.619–0.887]). Conclusion. Some donor characteristics persist to impact graft-survival (e.g., age) while the effect of others could be mitigated by elaborate donor-recipient match and care
Prospective evaluation of quality of life effects in patients undergoing palliative radiotherapy for brain metastases
Background: Recently published results of quality of life (QoL) studies indicated different outcomes of palliative radiotherapy for brain metastases. This prospective multi-center QoL study of patients with brain metastases was designed to investigate which QoL domains improve or worsen after palliative radiotherapy and which might provide prognostic information. Methods: From 01/2007-01/2009, n=151 patients with previously untreated brain metastases were recruited at 14 centers in Germany and Austria. Most patients (82 %) received whole-brain radiotherapy. QoL was measured with the EORTC-QLQ-C15-PAL and brain module BN20 before the start of radiotherapy and after 3 months. Results: At 3 months, 88/142 (62 %) survived. Nine patients were not able to be followed up. 62 patients (70.5 % of 3-month survivors) completed the second set of questionnaires. Three months after the start of radiotherapy QoL deteriorated significantly in the areas of global QoL, physical function, fatigue, nausea, pain, appetite loss, hair loss, drowsiness, motor dysfunction, communication deficit and weakness of legs. Although the use of corticosteroid at 3 months could be reduced compared to pre-treatment (63 % vs. 37 %), the score for headaches remained stable. Initial QoL at the start of treatment was better in those alive than in those deceased at 3 months, significantly for physical function, motor dysfunction and the symptom scales fatigue, pain, appetite loss and weakness of legs. In a multivariate model, lower Karnofsky performance score, higher age and higher pain ratings before radiotherapy were prognostic of 3-month survival. Conclusions: Moderate deterioration in several QoL domains was predominantly observed three months after start of palliative radiotherapy for brain metastases. Future studies will need to address the individual subjective benefit or burden from such treatment. Baseline QoL scores before palliative radiotherapy for brain metastases may contain prognostic information
The relentless variability of Mrk 421 from the TeV to the radio
The origin of the gamma-ray emission of the blazar Mrk 421 is still a matter
of debate. We used 5.5 years of unbiased observing campaign data, obtained
using the FACT telescope and the Fermi LAT detector at TeV and GeV energies,
the longest and densest so far, together with contemporaneous multi-wavelength
observations, to characterise the variability of Mrk 421 and to constrain the
underlying physical mechanisms. We studied and correlated light curves obtained
by ten different instruments and found two significant results. The TeV and
X-ray light curves are very well correlated with a lag of <0.6 days. The GeV
and radio (15 Ghz band) light curves are widely and strongly correlated.
Variations of the GeV light curve lead those in the radio. Lepto-hadronic and
purely hadronic models in the frame of shock acceleration predict proton
acceleration or cooling timescales that are ruled out by the short variability
timescales and delays observed in Mrk 421. Instead the observations match the
predictions of leptonic models.Comment: 10 pages, 8 figures, 1 tabl
Marina Abramović : from the artist to the present
Marina Abramovic: From the Artist to the Present mostra una investigació entom a l'artista serbia entre 2010 i 2014. El punt d'inici és The Artist is Present, la seva retrospectiva i obra homónima realitzada al Museum of Modern Art de Nova York, el punt de màxima consolidació d'una artista de performance a la historia de l'art i el reconeixement del públic i la crítica. El treball intenta mostrar la seva trajectoria posterior a l'obra per cobrir el buit bibliografic existent.Marina Abramovic: From the Artist to the Present muestra una investigación realizada entorno a la artista serbia entre 2010 y 2014. El punto de inicio es The Artist is Present, su retrospectiva y obra homónima en el Museum of Modern Art de Nueva York; el punto de máxima consolidación de una artista de performance en la historia del arte y el reconocimiento de público y crítica. El trabajo intenta mostrar la trayectoria posterior a esta obra para cubrir el vacío bibliográfico existente.Marina Abramovic: From the Artist to the Present is a research focused on the serbian artist between 2010 and 2014. The starting point is The Artist is Present, a retrospective in the Museum ofModem Art in New York and the main artwork of the exhibition. It was moment when a performance artist became most stablished by a big institution and art criticism. The main theme of the research is to create a documental resource to group all the artworks from 2010 in a single study
Broca's Region: Novel Organizational Principles and Multiple Receptor Mapping
A novel map of Broca's language region is proposed based on transmitter receptor distributions as functionally relevant molecular markers. It sheds new light on the relation between anatomy and functional segregation
Fractional variability—a tool to study blazar variability
Active Galactic Nuclei emit radiation over the whole electromagnetic spectrum up to TeV energies. Blazars are one subtype with their jets pointing towards the observer. One of their typical features is extreme variability on timescales, from minutes to years. The fractional variability is an often used parameter for investigating the degree of variability of a light curve. Different detection methods and sensitivities of the instruments result in differently binned data and light curves with gaps. As they can influence the physics interpretation of the broadband variability, the effects of these differences on the fractional variability need to be studied. In this paper, we study the systematic effects of completeness in time coverage and the sampling rate. Using public data from instruments monitoring blazars in various energy ranges, we study the variability of the bright TeV blazars Mrk 421 and Mrk 501 over the electromagnetic spectrum, taking into account the systematic effects, and compare our findings with previous results. Especially in the TeV range, the fractional variability is higher than in previous studies, which can be explained by the much longer (seven years compared to few weeks) and more complete data sample
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