468 research outputs found
The position of graptolites within Lower Palaeozoic planktic ecosystems.
An integrated approach has been used to assess the palaeoecology of graptolites both as a discrete group and also as a part of the biota present within Ordovician and Silurian planktic realms. Study of the functional morphology of graptolites and comparisons with recent ecological analogues demonstrates that graptolites most probably filled a variety of niches as primary consumers, with modes of life related to the colony morphotype. Graptolite coloniality was extremely ordered, lacking any close morphological analogues in Recent faunas. To obtain maximum functional efficiency, graptolites would have needed varying degrees of coordinated automobility. A change in lifestyle related to ontogenetic changes was prevalent within many graptolite groups. Differing lifestyle was reflected by differing reproductive strategies, with synrhabdosomes most likely being a method for rapid asexual reproduction. Direct evidence in the form of graptolithophage 'coprolitic' bodies, as well as indirect evidence in the form of probable defensive adaptations, indicate that graptolites comprised a food item for a variety of predators. Graptolites were also hosts to a variety of parasitic organisms and provided an important nutrient source for scavenging organisms
Power in Transition: An Interdisciplinary Framework to Study Power in Relation to Structural Change
This article conceptualizes power in the context of long-term process of structural change. First, it discusses the field of transition studies, which deals with processes of structural change in societal systems on the basis of certain
presumptions about power relations, but still lacks an explicit conceptualization of power. Then the article discusses some prevailing points of contestation in debates on power. It is argued that for the context of transition studies, it is necessary to develop an interdisciplinary framework in which
power is explicitly conceptualized in relation to change. Subsequently, such a framework is presented, with reference to existing literature on power.
Starting with a philosophical and operational definition of power, a typology is developed of the different ways in which power can be exercised, explicitly including innovative power and transformative power. Finally, the presented power framework is applied to transition studies, redefining pivotal transition
concepts in terms of power and formulating hypotheses on the role of power in transitions. By doing so, the article not only offers an interdisciplinary framework to study power in the context of transition studies, but also contributes to power debates more generally by including innovation and
transformation as acts of power, and thereby proposes a re-conceptualization of the relation between power and structural change
Physicians' acquaintance with a new procedure results in higher patient referral: experience of Kosovo in coronary angiography
The first coronary angiography in Kosovo was completed in 2003. We analyzed coronary angiographies performed in our center from October 2003 until October 2009 divided into two 3-year periods. The aims of our study were: to compare the number of coronary angiographies completed in the two periods; to evaluate the prevalence of normal coronary angiographies diagnosed in the first period compared to the second period; and to assess the prevalence of advanced coronary artery disease in the first three years compared to the last three years. This was a prospective angiography study that included 1,139 patients. The first group had 422 patients, who underwent the angiography procedure during the first three years, and the second group had 717 patients that went through the procedure during the last three years. In the first year, 109 coronary angiographies were completed, followed by 137, 176, 213, 218 and 286 (P<0.001) procedures in the subsequent years. In the first period, a normal or near-normal coronary artery profile was found in 27% of patients, while this figure rose to approximately 39% in the second period (P=0.004). Advanced coronary artery disease was found in 45% of the patients who underwent coronary angiography during the first three years, whereas this figure was only 24% of cases during the second period (P<0.001). We believe that the availability of specialized resources and the physicians' familiarity with coronary angiography in our country influenced their decision to refer more patients for this procedure
Genome-wide association analyses identify 13 new susceptibility loci for generalized vitiligo
We previously reported a genome-wide association study (GWAS) identifying 14 susceptibility loci for generalized vitiligo. We report here a second GWAS (450 individuals with vitiligo (cases) and 3,182 controls), an independent replication study (1,440 cases and 1,316 controls) and a meta-analysis (3,187 cases and 6,723 controls) identifying 13 additional vitiligo-associated loci. These include OCA2-HERC2 (combined P = 3.80 Ă 10 ), MC1R (P = 1.82 Ă 10 ), a region near TYR (P = 1.57 Ă 10 ), IFIH1 (P = 4.91 Ă 10 ), CD80 (P = 3.78 Ă 10 ), CLNK (P = 1.56 Ă 10 ), BACH2 (P = 2.53 Ă 10 ), SLA (P = 1.58 Ă 10 ), CASP7 (P = 3.56 Ă 10 ), CD44 (P = 1.78 Ă 10 ), IKZF4 (P = 2.75 Ă 10 ), SH2B3 (P = 3.54 Ă 10 ) and TOB2 (P = 6.81 Ă 10 ). Most vitiligo susceptibility loci encode immunoregulatory proteins or melanocyte components that likely mediate immune targeting and the relationships among vitiligo, melanoma, and eye, skin and hair coloration
Metal enrichment processes
There are many processes that can transport gas from the galaxies to their
environment and enrich the environment in this way with metals. These metal
enrichment processes have a large influence on the evolution of both the
galaxies and their environment. Various processes can contribute to the gas
transfer: ram-pressure stripping, galactic winds, AGN outflows, galaxy-galaxy
interactions and others. We review their observational evidence, corresponding
simulations, their efficiencies, and their time scales as far as they are known
to date. It seems that all processes can contribute to the enrichment. There is
not a single process that always dominates the enrichment, because the
efficiencies of the processes vary strongly with galaxy and environmental
properties.Comment: 18 pages, 8 figures, accepted for publication in Space Science
Reviews, special issue "Clusters of galaxies: beyond the thermal view",
Editor J.S. Kaastra, Chapter 17; work done by an international team at the
International Space Science Institute (ISSI), Bern, organised by J.S.
Kaastra, A.M. Bykov, S. Schindler & J.A.M. Bleeke
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory
Data from the Pierre Auger Observatory are analyzed to search for
anisotropies near the direction of the Galactic Centre at EeV energies. The
exposure of the surface array in this part of the sky is already significantly
larger than that of the fore-runner experiments. Our results do not support
previous findings of localized excesses in the AGASA and SUGAR data. We set an
upper bound on a point-like flux of cosmic rays arriving from the Galactic
Centre which excludes several scenarios predicting sources of EeV neutrons from
Sagittarius . Also the events detected simultaneously by the surface and
fluorescence detectors (the `hybrid' data set), which have better pointing
accuracy but are less numerous than those of the surface array alone, do not
show any significant localized excess from this direction.Comment: Matches published versio
Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory
Atmospheric parameters, such as pressure (P), temperature (T) and density,
affect the development of extensive air showers initiated by energetic cosmic
rays. We have studied the impact of atmospheric variations on extensive air
showers by means of the surface detector of the Pierre Auger Observatory. The
rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find
that the observed behaviour is explained by a model including the effects
associated with the variations of pressure and density. The former affects the
longitudinal development of air showers while the latter influences the Moliere
radius and hence the lateral distribution of the shower particles. The model is
validated with full simulations of extensive air showers using atmospheric
profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle
Physic
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