Non-substitutional single-atom defects in the Ge_(1-x)Sn_x alloy

Ge_(1-x)Sn_x alloys have proved difficult to form at large x, contrary to what happens with other group IV semiconductor combinations. However, at low x they are typical examples of well-behaved substitutional compounds, which is desirable for harnessing the electronic properties of narrow band semiconductors. In this paper, we propose the appearance of another kind of single-site defect ($\beta-Sn$), consisting of a single Sn atom in the center of a Ge divacancy, that may account for these facts. Accordingly, we examine the electronic and structural properties of these alloys by performing extensive numerical ab-initio calculations around local defects. The results show that the environment of the $\beta$ defect relaxes towards a cubic octahedral configuration, facilitating the nucleation of metallic white tin and its segregation, as found in amorphous samples. Using the information stemming from these local defect calculations, we built a simple statistical model to investigate at which concentration these $\beta$ defects can be formed in thermal equilibrium. These results agree remarkably well with experimental findings, concerning the critical concentration above which the homogeneous alloys cannot be formed at room temperature. Our model also predicts the observed fact that at lower temperature the critical concentration increases. We also performed single site effective-field calculations of the electronic structure, which further support our hypothesis.Comment: 12 pages, 1 table, 16 figure

Spatial patterning in modified Turing systems: Application to pigmentation patterns on marine fish

In this paper we extend the study of Turing models to investigate the rôle of boundary conditions, parameter modulation, domain growth, and coupling of models. Our numerical simulations show that such modifications lead to patterns that cannot be reproduced by the standard model. By comparing our results with pigmentation patterning on marine fish we conclude that such models may have wider application than originally imagined

Rangeland Degradation in Mongolia – Using State and Transition Models to Help Understand Rangeland Dynamics

Rangeland degradation and soil erosion pose constant challenges to the management of natural resources in Mongolia. Large increases in livestock numbers since the early 1990s, together with increasing temperatures and higher frequency of extreme weather events have led to widespread degradation of rangeland resources, to the extent that today, nearly 57% of rangelands in Mongolia are considered degraded to some degree. New ways of understanding the dynamics of rangeland ecosystems and guidelines to conserve healthy and productive rangelands are urgently needed. The application of State and Transition Models (STMs) in ecosystem management has shown promise to understand the mechanistic processes behind rangeland degradation and to suggest appropriate interventions for maintaining the health or restoring degraded rangelands. The Green Gold-Animal Health project funded by the Swiss Development Agency in Mongolia was the first initiative aimed at developing and applying STMs to Mongolian rangeland management. Here we describe the development of STMs for the most common rangeland types in Mongolia, including the definition of reference and alternative rangeland states and “recovery classes”, based on the timelines and management actions needed to recover a reference state. Our results show that STMs are effective tools for analysing and interpreting rangeland health monitoring data and provide a scientific basis for planning and implementing resilience-based rangeland management. Furthermore, STMs facilitate synthesis of available knowledge and help identify areas where more information is needed. In summary, STMs have the potential to serve as a valuable tool for better communication of rangeland health assessments and decision making to facilitate appropriate management

Multinet : enabler for next generation enterprise wireless services

Wireless communications are currently experiencing a fast migration toward the beyond third-generation (B3G)/fourth generation (4G) era. This represents a generational change in wireless systems: new capabilities related to mobility and new services support is required and new concepts as individual-centric, user-centric or ambient-aware communications are included. One of the main restrictions associated to wireless technology is mobility management, this feature was not considered in the design phase; for this reason, a complete solution is not already found, although different solutions are proposed and are being proposed. In MULTINET project, features as mobility and multihoming are applied to wireless network to provide the necessary network and application functionality enhancements for seamless data communication mobility considering end-user scenario and preferences. The aim of this paper is to show the benefits of these functionalities from the Service Providers and final User point of view

Fitness for purpose of routinely recorded health data to identify patients with complex diseases: The case of Sjögren's syndrome

Background: This study is part of the EU-funded project HarmonicSS, aimed at improving the treatment and diagnosis of primary Sjögren's syndrome (pSS). pSS is an underdiagnosed, long-term autoimmune disease that affects particularly salivary and lachrymal glands. Objectives: We assessed the usability of routinely recorded primary care and hospital claims data for the identification and validation of patients with complex diseases such as pSS. Methods: pSS patients were identified in primary care by translating the formal inclusion and exclusion criteria for pSS into a patient selection algorithm using data from Nivel Primary Care Database (PCD), covering 10% of the Dutch population between 2006 and 2017. As part of a validation exercise, the pSS patients found by the algorithm were compared to Diagnosis Related Groups (DRG) recorded in the national hospital insurance claims database (DIS) between 2013 and 2017. Results: International Classification of Primary Care (ICPC) coded general practitioner (GP) contacts combined with the mention of “Sjögren” in the disease episode titles, were found to best translate the formal classification criteria to a selection algorithm for pSS. A total of 1462 possible pSS patients were identified in primary care (mean prevalence 0.7‰, against 0.61‰ reported globally). The DIS contained 208 545 patients with a Sjögren related DRG or ICD10 code (prevalence 2017: 2.73‰). A total of 2 577 577 patients from Nivel PCD were linked to the DIS database. A total of 716 of the linked pSS patients (55.3%) were confirmed based on the DIS. Conclusion: Our study finds that GP electronic health records (EHRs) lack the granular information needed to apply the formal diagnostic criteria for pSS. The developed algorithm resulted in a patient selection that approximates the expected prevalence and characteristics, although only slightly over half of the patients were confirmed using the DIS. Without more detailed diagnostic information, the fitness for purpose of routine EHR data for patient identification and validation could not be determined

Un nuevo Eleutherodactylus (Anura, Leptodactylidae) de la Cordillera de Mérida, Andes de Venezuela

A new frog of the genus Eleutherodactylus is described from the Cordillera de Mérida, Venezuelan Andes. The species is distinguished from others by its moderate size, first finger equal or shorter than second, basal webbing on toes, and dominant colour immaculate brown or with a few spots. The species is compared with the groups unistrigatus and conspicillatus, but not assigned to either of them. A distribution map and a sonogram (of the song) are presented. Comments about current knowledge of frogs of the genus Eleutherodactylus in Venezuela are provided.Se describe una nueva rana del género Eleutherodactylus de la Cordillera de Mérida, Andes de Venezuela. La especie se distingue del resto de congéneres por su tamaño moderado, primer dedo de la mano igual o más corto que el segundo, palmeadura pedal basal, y color dominante marrón uniforme o con pocas manchas. Se compara la especie con los grupos unistrigatus y conspicillatus, pero no se asigna a ninguno de ellos. Se presenta un mapa de distribución y un sonograma del canto. Se comenta brevemente sobre el conocimiento actual de las ranas del género Eleutherodactylus en Venezuela

Patrones de diversidad de poliquetos en hábitats intermareales tropicales selectos

Few studies have quantitatively compared benthic macrofaunal assemblages between different tropical intertidal habitats over differing spatial scales. The present study uses spatially nested material from vegetated (seagrass) and non-vegetated (mudflat) habitats in SW Thailand to address this issue. Polychaetes were the numerically dominant component of benthic assemblages throughout the region, comprising over 74% of the total macrofauna. Despite great within-site and sample variation, based on species diversity, polychaete assemblages were mostly site-specific. Not so visibly obvious were the evident differences in polychaete assemblages between habitats. The spatial pattern of polychaete diversity is explored.Pocos estudios han comparado cuantitativamente el macrozoobentos entre diferentes hábitats intermareales tropicales a diferentes escalas espaciales. Para remediar esta situación, esta investigación utiliza y compara material colectado en praderas marinas y zonas sin vegetación en la costa suroeste de Tailandia a diferentes escalas espaciales. Los poliquetos formaron la mayor parte del zoobentos, constituyendo el 74% del total. Pese al alto nivel de variación entre muestras, basado en la diversidad de especies, los conjuntos de poliquetos mostraron mayor afinidad a su lugar de colecta. Diferencias entre cada hábitat, aunque difíciles de apreciar a simple vista, son corroboradas estadísticamente. Se exploran cambios en la diversidad asociados con cambios en la escala espacial. &nbsp

A retrospective report (2003–2013) of the complications associated with the use of a one-man (head and tail) rope recovery system in horses following general anaesthesia

Abstract Background The mortality rate of horses undergoing general anaesthesia is high when compared to humans or small animal patients. One of the most critical periods during equine anaesthesia is recovery, as the horse attempts to regain a standing position. This study was performed in a private equine practice in Belgium that uses a purpose-designed one-man (head and tail) rope recovery system to assist the horse during the standing process. The main purpose of the retrospective study was to report and analyse complications and the mortality rate in horses during recovery from anaesthesia using the described recovery system. Information retrieved from the medical records included patient signalment, anaesthetic protocol, duration of anaesthesia, ASA grade, type of surgery, recovery time and complications during recovery. Sedation was administered to all horses prior to recovery with the rope system. Complications were divided into major complications in which the horse was euthanized and minor complications where the horse survived. Major complications were further subdivided into those where the rope system did not contribute to the recovery complication (Group 1) and those where it was not possible to determine if the rope system was of any benefit (Group 2). Results Five thousand eight hundred fifty two horses recovered from general anaesthesia with rope assistance. Complications were identified in 30 (0.51%). Major complications occurred in 12 horses (0.20%) of which three (0.05%) were assigned to Group 1 and nine (0.15%) to Group 2. Three horses in Group 2 suffered musculoskeletal injuries (0.05%). Eighteen horses (0.31%) suffered minor complications, of which five (0.08%) were categorised as failures of the recovery system. Conclusions This study reports the major and minor complication and mortality rate during recovery from anaesthesia using a specific type of rope recovery system. Mortality associated with the rope recovery system was low. During recovery from anaesthesia this rope system may reduce the risk of lethal complications, particularly major orthopaedic injuries

Reactivity of Gold Hydrides: O2 Insertion into the Au–H Bond

Dioxygen reacts with the gold(I) hydride (IPr)AuH under insertion to give the hydroperoxide, (IPr)AuOOH, a long-postulated reaction in gold catalysis and the first demonstration of O2 activation by Au-H in a well-defined system. Subsequent condensation gave the peroxide (IPr)Au-OO-Au(IPr) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene). The reaction kinetics are reported, as well as the reactivity of Au(I) hydrides with radical scavengers