200 research outputs found
Idiopathic orthostatic hypotension: Recent data (eleven cases) and review of the literature
Eight cases of Shy-Drager syndrome and three of Bradbury-Eggleston idiopathic orthostatic hypotension were examined. In all cases, examination of circulatory reflexes showed major dysfunction of the sympathetic vasoconstrictor system. Anomalies in the vagal cardiomoderator system were less constant. Normal urinary elimination of catecholamines was recorded daily. Characteristically, no elevation of blood or urine norepinephrine levels were found in orthostatism. Insulin hypoglycemia normally raised urinary adrenalin elimination in three of ten patients. Plasma dopa-beta-hydroxylase activity was normal. Renin-angiotensin-aldosterone system showed variable activity at basal state but usually rose during orthostatism. On the average, very low homovanillic acid levels were found in cerebrospinal fluid before and after probenecid; hydroxyindolacetic acid was normal. Cerebral autoregulation had deteriorated in two of four cases. Physiopathologically the two clinical types are indistinguishable with or without central neurological signs
One dimensional exciton luminescence induced by extended defects in nonpolar (Al,Ga)N/GaN quantum wells
In this study, we present the optical properties of nonpolar GaN/(Al,Ga)N single quantum wells (QWs) grown on either a- or m-plane GaN templates for Al contents set below 15%. In order to reduce the density of extended defects, the templates have been processed using the epitaxial lateral overgrowth technique. As expected for polarization-free heterostructures, the larger the QW width for a given Al content, the narrower the QW emission line. In structures with an Al content set to 5 or 10%, we also observe emission from excitons bound to the intersection of I1-type basal plane stacking faults (BSFs) with the QW. Similarly to what is seen in bulk material, the temperature dependence of BSF-bound QW exciton luminescence reveals intra-BSF localization. A qualitative model evidences the large spatial extension of the wavefunction of these BSF-bound QW excitons, making them extremely sensitive to potential fluctuations located in and away from BSF. Finally, polarization-dependent measurements show a strong emission anisotropy for BSF-bound QW excitons, which is related to their one-dimensional character and that confirms that the intersection between a BSF and a GaN/(Al,Ga)N QW can be described as a quantum wire
How stratospheric are deep stratospheric intrusions? LUAMI 2008
A large-scale comparison of water-vapour vertical-sounding instruments took place over central Europe on 17 October 2008, during a rather homogeneous deep stratospheric intrusion event (LUAMI, Lindenberg Upper-Air Methods Intercomparison). The measurements were carried out at four observational sites: Payerne (Switzerland), Bilthoven (the Netherlands), Lindenberg (north-eastern Germany), and the Zugspitze mountain (Garmisch-Partenkichen, German Alps), and by an airborne water-vapour lidar system creating a transect of humidity profiles between all four stations. A high data quality was verified that strongly underlines the scientific findings. The intrusion layer was very dry with a minimum mixing ratios of 0 to 35âŻppm on its lower west side, but did not drop below 120âŻppm on the higher-lying east side (Lindenberg). The dryness hardens the findings of a preceding study (âPart 1â, Trickl et al., 2014) that, e.g., 73âŻ% of deep intrusions reaching the German Alps and travelling 6 days or less exhibit minimum mixing ratios of 50âŻppm and less. These low values reflect values found in the lowermost stratosphere and indicate very slow mixing with tropospheric air during the downward transport to the lower troposphere. The peak ozone values were around 70âŻppb, confirming the idea that intrusion layers depart from the lowermost edge of the stratosphere. The data suggest an increase of ozone from the lower to the higher edge of the intrusion layer. This behaviour is also confirmed by stratospheric aerosol caught in the layer. Both observations are in agreement with the idea that sections of the vertical distributions of these constituents in the source region were transferred to central Europe without major change. LAGRANTO trajectory calculations demonstrated a rather shallow outflow from the stratosphere just above the dynamical tropopause, for the first time confirming the conclusions in âPart 1â from the Zugspitze CO observations. The trajectories qualitatively explain the temporal evolution of the intrusion layers above the four stations participating in the campaign
Disorder Effects on Exciton-Polariton Condensates
The impact of a random disorder potential on the dynamical properties of Bose
Einstein condensates is a very wide research field. In microcavities, these
studies are even more crucial than in the condensates of cold atoms, since
random disorder is naturally present in the semiconductor structures. In this
chapter, we consider a stable condensate, defined by a chemical potential,
propagating in a random disorder potential, like a liquid flowing through a
capillary. We analyze the interplay between the kinetic energy, the
localization energy, and the interaction between particles in 1D and 2D
polariton condensates. The finite life time of polaritons is taken into account
as well. In the first part, we remind the results of [G. Malpuech et al. Phys.
Rev. Lett. 98, 206402 (2007).] where we considered the case of a static
condensate. In that case, the condensate forms either a glassy insulating phase
at low polariton density (strong localization), or a superfluid phase above the
percolation threshold. We also show the calculation of the first order spatial
coherence of the condensate versus the condensate density. In the second part,
we consider the case of a propagating non-interacting condensate which is
always localized because of Anderson localization. The localization length is
calculated in the Born approximation. The impact of the finite polariton life
time is taken into account as well. In the last section we consider the case of
a propagating interacting condensate where the three regimes of strong
localization, Anderson localization, and superfluid behavior are accessible.
The localization length is calculated versus the system parameters. The
localization length is strongly modified with respect to the non-interacting
case. It is infinite in the superfluid regime whereas it is strongly reduced if
the fluid flows with a supersonic velocity.Comment: chapter for a book "Exciton Polaritons in Microcavities: New
Frontiers" by Springer (2012), the original publication is available at
http://www.springerlink.co
Haematopoietic cell transplantation in Switzerland, changes and results over 20 years: a report from the Swiss Blood Stem Cell Transplantation Working Group for Blood and Marrow Transplantation registry 1997-2016.
In 1997, the Swiss Blood Stem Cell Transplantation Group (SBST) initiated a mandatory national registry for all haematopoietic stem cell transplants (HCTs) in Switzerland. As of 2016, after 20 years, information was available for 7899 patients who had received an HCT (2781 allogeneic [35%] and 5118 autologous [65%]). As some patients had more than one transplant the total number of transplants was 3067 allogeneic and 6448 autologous. We compared patient characteristics and outcome of the first decade (1997-2006) and second decade (2007-2016) of the registry. There were numerous changes over time. For allogeneic HCT, transplant rates, and therefore use of HCT technology, increased from 14 to 21.8 HCTs per 1 million inhabitants per year from the first to the second decade. Likewise autologous HCTs increased from 24.8 to 37.2 annually corrected for population growth. Allogeneic transplant recipients were older (38.4 vs 48.3 years) and more frequently had unrelated donors in the second decade. Similarly, age increased for recipients of autologous HCT (50.8 vs 56.4 years). Analysis of outcome showed that the probabilities of overall and progression-free survival were stable over time, in spite of the treatment of older and higher risk patients. In multivariate analysis, nonrelapse mortality decreased in recipients of allogeneic HCT (relative risk 0.68, 95% confidence interval 0.52-0.87) over the two decades. Improvement in adjusted nonrelapse mortality compensated for the fact that higher risk patients were treated in more recent years, resulting in similar overall survival. Five-year survival probabilities were 56% (53-59%) in the first and 54% (51-57%) in the second decade for allogeneic HCT, and 59% (57-61%) in the first and 61% (59-63%) in the second decade for autologous HCT. Detailed analyses of changes over time are presented. This study included all HCTs performed in Switzerland during the period of observation and the data are useful for quality assurance programmes, healthcare cost estimation and healthcare planning. Between 50 and 60% of patients were long-term survivors after both types of HCT, indicating growing populations of surviving patients requiring long-term care and observation
Building a multisystemic understanding of societal resilience to the COVID-19 pandemic
The current global systemic crisis reveals how globalised societies are unprepared to face a pandemic. Beyond the dramatic loss of human life, the COVID-19 pandemic has triggered widespread disturbances in health, social, economic, environmental and governance systems in many countries across the world. Resilience describes the capacities of natural and human systems to prevent, react to and recover from shocks. Societal resilience to the current COVID-19 pandemic relates to the ability of societies in maintaining their core functions while minimising the impact of the pandemic and other societal effects. Drawing on the emerging evidence about resilience in health, social, economic, environmental and governance systems, this paper delineates a multisystemic understanding of societal resilience to COVID-19. Such an understanding provides the foundation for an integrated approach to build societal resilience to current and future pandemics
The Development of Cephalic Armor in The Tokay Gecko (Squamata: Gekkonidae: \u3cem\u3eGekko gecko\u3c/em\u3e)
Armored skin resulting from the presence of bony dermal structures, osteoderms, is an exceptional phenotype in gekkotans (geckos and flap-footed lizards) only known to occur in three genera: Geckolepis, Gekko, and Tarentola. The Tokay gecko (Gekko gecko LINNAEUS 1758) is among the best-studied geckos due to its large size and wide range of occurrence, and although cranial dermal bone development has previously been investigated, details of osteoderm development along a size gradient remain less well-known. Likewise, a comparative survey of additional species within the broader Gekko clade to determine the uniqueness of this trait has not yet been completed. Here, we studied a large sample of gekkotans (38 spp.), including 18 specimens of G. gecko, using X-rays and high-resolution computed tomography for visualizing and quantifying the dermal armor in situ. Results from this survey confirm the presence of osteoderms in a second species within this genus, Gekko reevesii GRAY 1831, which exhibits discordance in timing and pattern of osteoderm development when compared with its sister taxon, G. gecko. We discuss the developmental sequence of osteoderms in these two species and explore in detail the formation and functionality of these enigmatic dermal ossifications. Finally, we conducted a comparative analysis of endolymphatic sacs in a wide array of gekkotans to explore previous ideas regarding the role of osteoderms as calcium reservoirs. We found that G. gecko and other gecko species with osteoderms have highly enlarged endolymphatic sacs relative to their body size, when compared to species without osteoderms, which implies that these membranous structures might fulfill a major role of calcium storage even in species with osteoderms
Genetic and phenotypic spectrum associated with IFIH1 gain-of-function
IFIH1 gainâofâfunction has been reported as a cause of a type I interferonopathy encompassing a spectrum of autoinflammatory phenotypes including AicardiâGoutiĂšres syndrome and Singleton Merten syndrome. Ascertaining patients through a European and North American collaboration, we set out to describe the molecular, clinical and interferon status of a cohort of individuals with pathogenic heterozygous mutations in IFIH1. We identified 74 individuals from 51 families segregating a total of 27 likely pathogenic mutations in IFIH1. Ten adult individuals, 13.5% of all mutation carriers, were clinically asymptomatic (with seven of these aged over 50 years). All mutations were associated with enhanced type I interferon signaling, including six variants (22%) which were predicted as benign according to multiple in silico pathogenicity programs. The identified mutations cluster close to the ATP binding region of the protein. These data confirm variable expression and nonpenetrance as important characteristics of the IFIH1 genotype, a consistent association with enhanced type I interferon signaling, and a common mutational mechanism involving increased RNA binding affinity or decreased efficiency of ATP hydrolysis and filament disassembly rate
Catalonia rescaling Spain : is it feasible to accommodate its "stateless citizenship"?
The Spanish nation-state is gradually being rescaled by Catalonia's âsecession crisis.â Recently and dramatically, in the aftermath of the âillegalâ and âconstitutive referendumâ that took place on 1 October 2017, 2,286,217 Catalan citizens attempted to exercise the âright to decideâ to ultimately become âstateless citizens.â This paper examines this rescaling process that has been forming in Barcelona since 10 July 2010 when 1 million Catalan citizens marched to claim their âright to decideâ on secession. This paper concludes that, at present, it is not feasible for the Spanish nation-state to accommodate Catalonia's âstateless citizenship.â
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