Silicon surface passivation by Al2O3: Recombination parameters and inversion layer solar cells

The interface between p- and n-type FZ-Si and an amorphous aluminum oxide (Al2O3) surface passivation layer deposited by plasma-assisted atomic layer deposition (ALD) was investigated by frequency-dependent conductance measurements. The hole capture cross section in the lower half of the bandgap, σp = (4±3)×10 -16 cm2, was found to be independent of energy. The electron capture cross section σn in the upper half of the bandgap decreases from σn = (7±4)×10-15 cm2 at midgap over two orders of magnitude towards the conduction band edge. Numerical simulations of the effective surface recombination velocity based on these recombination parameters show a good agreement with experimental surface recombination velocities for a wide range of excess carrier and surface charge densities. Carrier transport in the inversion layer formed at the n-Si/Al2O3 interface was investigated yielding a sheet resistance of 15 kΩ/, which was reduced to 6 kΩ/ for a surface charge density of -2×1013 cm-2 obtained by corona charging. The applicability of Al2O3 inversion layers as emitters in n-type inversion layer solar cells was demonstrated by short circuit current densities of up to 25 mA/cm2, which show a pronounced dependence on surface charge density.BMU/032505

Diagnostic Performance of the Darth Vader Sign for the Diagnosis of Lumbar Spondylolysis in Routinely Acquired Abdominal CT

Spondylolysis is underdiagnosed and often missed in non-musculoskeletal abdominal CT imaging. Our aim was to assess the inter-reader agreement and diagnostic performance of a novel "Darth Vader sign" for the detection of spondylolysis in routine axial images. We performed a retrospective search in the institutional report archives through keyword strings for lumbar spondylolysis and spondylolisthesis. Abdominal CTs from 53 spondylolysis cases (41% female) and from controls (n = 6) without spine abnormalities were identified. A total of 139 single axial slices covering the lumbar spine (86 normal images, 40 with spondylolysis, 13 with degenerative spondylolisthesis without spondylolysis) were exported. Two radiology residents rated all images for the presence or absence of the "Darth Vader sign". The diagnostic accuracy for both readers, as well as the inter-reader agreement, was calculated. The "Darth Vader sign" showed an inter-reader agreement of 0.77. Using the "Darth Vader sign", spondylolysis was detected with a sensitivity and specificity of 65.0-88.2% and 96.2-99.0%, respectively. The "Darth Vader sign" shows excellent diagnostic performance at a substantial inter-reader agreement for the detection of spondylolysis. Using the "Darth Vader sign" in the CT reading routine may be an easy yet effective tool to improve the detection rate of spondylolysis in non-musculoskeletal cases and hence improve patient care

Mercados de trabalho digitais na economia de plataforma. Mapeando os Desafios Políticos do Crowd Work e Gig Work

La llamada “economía colaborativa” es un tema muy debatido. Uber, Airbnb, Helpling y muchos otros modelos de negocios basados en plataformas buscan “trastocar” aquellas industrias que describen como “anquilosadas” y poco amigables para el usuario. Estos jugadores afirman estar creando nuevos servicios más flexibles y rentables. En efecto, las nuevas plataformas que sirven como intermediarias entre la oferta y la demanda, tienen muchas contribuciones valiosas para ofrecer. Sin embargo, las nuevas plataformas se encuentran cada vez más asediadas por las críticas. Por lo general, estas dependen de una fuerza laboral conformada por trabajadores independientes [independent contractors], que trabajan por cuenta propia y bajo su propio riesgo, por salarios bajos y sin ningún tipo de seguridad social. En este sentido, ni los proveedores de la plataforma ni sus clientes asumen el papel y las responsabilidades de un empleador. Las leyes laborales, la protección de los trabajadores, las normas de salud y seguridad, la calidad del trabajo y las cargas sociales recaen principalmente sobre los trabajadores, quienes tampoco tienen derecho al tipo de participación común en otros sectores. Los clientes de las plataformas obtienen acceso a una fuerza laboral a demanda [on-demand], mientras que los trabajadores que proveen la mano de obra están sujetos a condiciones laborales precarias. En este contexto, la Friedrich-Ebert-Stiftung (FES) decidió examinar más de cerca los modelos de negocio digitales basados en plataformas y sus implicancias para la economía y la sociedad. Si bien las plataformas digitales han llegado a desempeñar un rol relevante en muchas ramas de la economía, la presente publicación se centra en las más controvertidas sociopolíticamente, es decir, las plataformas de trabajo digital [digital labour platforms]. El estudio explica los mecanismos básicos de las tres caras de los mercados de trabajo digital y compara sus variantes y subcategorías. También explica las características específicas y los desafíos de las diferentes categorías y propone puntos de partida para la toma de decisiones políticas.The so-called “sharing economy” is a much-debated topic. Uber, Airbnb, Helpling and many other platform-based business models want to “disrupt” industries that they portray as “ossified” and user-unfriendly. The contenders claim to create new services that are more flexible and cost-efficient. And indeed, the new platforms, which serve as an intermediary between supply and demand, have many valuable contributions to offer. Nevertheless, the new platforms are increasingly beset by criticism. Usually they rely on a workforce of independent contractors, who work on their own account and at their own risk, for low wages and without social security. Neither the platform providers nor their clients take on the role and responsibilities of an employer. Labour laws, worker protection, health and safety regulations, quality of work and social security contributions mostly fall to the responsibility of the independent contractors alone, who are also not entitled to the kind of workers’ participation common in other sectors. The clients of the platforms essentially gain access to an on-demand workforce, while the independent contractors who provide the labour are subject to precarious working conditions. Against this background, the Friedrich-Ebert-Stiftung (FES) decided to have a closer look at platform-based digital business models and their implications for the economy and for society. While digital platforms have come to play a role in many branches of the economy, the present publication is focussed on the socio-politically most contested ones, namely digital labour platforms. The study explains the basic mechanisms of three-sided digital labour markets and compares its variants and subcategories. It also explains the specific features and challenges of the different categories and pro-poses starting points for political measures.A chamada “economia compartilhada” é um tema muito debatido. Uber, Airbnb, Helpling e muitos outros modelos de negócios baseados em plataforma querem “perturbar” setores que eles retratam como “ossificados” e hostis ao usuário. Os concorrentes pretendem criar novos serviços mais flexíveis e econômicos. E, de fato, as novas plataformas, que servem como intermediárias entre a oferta e a demanda, têm muitas contribuições valiosas a oferecer. No entanto, as novas plataformas são cada vez mais assediadas por críticas. Normalmente contam com uma força de trabalho de contratados independentes, que trabalham por conta própria e por sua conta e risco, com baixos salários e sem seguridade social. Nem os fornecedores de plataforma nem seus clientes assumem o papel e as responsabilidades de um empregador. As leis trabalhistas, a proteção do trabalhador, os regulamentos de saúde e segurança, a qualidade do trabalho e as contribuições para a seguridade social recaem principalmente sobre a responsabilidade dos contratantes independentes, que também não têm direito ao tipo de participação dos trabalhadores comum em outros setores. Os clientes das plataformas têm essencialmente acesso a mão-de-obra on-demand, enquanto os autônomos que fornecem a mão-de-obra estão sujeitos a condições de trabalho precárias. Neste contexto, a Friedrich-Ebert-Stiftung (FES) decidiu examinar mais de perto os modelos de negócios digitais baseados em plataformas e suas implicações para a economia e a sociedade. Embora as plataformas digitais tenham vindo a desempenhar um papel em muitos ramos da economia, a presente publicação centra-se nos mais contestados sócio-politicamente, nomeadamente as plataformas digitais de trabalho. O estudo explica os mecanismos básicos dos mercados de trabalho digitais de três lados e compara suas variantes e subcategorias. Também explica as características específicas e os desafios das diferentes categorias e propõe pontos de partida para medidas políticas.Facultad de Trabajo Socia

Evaluating sociometer theory in children\u27s everyday lives. Inclusion, but not exclusion by peers at school is related to within-day change in self-esteem

Sociometer theory proposes that a person\u27s self-esteem is a permanent monitor of perceived social inclusion and exclusion in a given situation. Despite this within-person perspective, respective research in children\u27s everyday lives is lacking. In three intensive longitudinal studies, we examined whether children\u27s self-esteem was associated with social inclusion and exclusion by peers at school. Based on sociometer theory, we expected social inclusion to positively predict self-esteem and social exclusion to negatively predict self-esteem on within- and between-person levels. Children aged 9-12 years reported state self-esteem twice per day (morning and evening) and social inclusion and exclusion once per day for two (Study 1) and four weeks (Studies 2-3). Consistently across studies, we found that social inclusion positively predicted evening self-esteem on within- and between-person levels. By contrast, social exclusion was not associated with evening self-esteem on the within-person level. On the between-person level, social exclusion was negatively linked to evening self-esteem only in Study 1. Multilevel latent change score models revealed that children\u27s self-esteem changed from mornings (before school) to evenings (after school) depending on their perceived daily social inclusion, but not exclusion. The findings are discussed in light of sociometer theory and the bad-is-stronger-than-good phenomenon. (DIPF/Orig.

Optomechanical circuits for nanomechanical continuous variable quantum state processing

We propose and analyze a nanomechanical architecture where light is used to perform linear quantum operations on a set of many vibrational modes. Suitable amplitude modulation of a single laser beam is shown to generate squeezing, entanglement, and state-transfer between modes that are selected according to their mechanical oscillation frequency. Current optomechanical devices based on photonic crystals may provide a platform for realizing this scheme.Comment: 11 pages, 5 figure

All eyes on the signal? - Mapping cohesive discourse structures with eye-tracking data of explanation videos

In this paper, we consider the issue of how the fine-grained multimodal design of educational explanation videos, such as those widely available on YouTube and other platforms, may be made accessible to empirical studies of reception and effectiveness. This is necessary because previous research has often led to conflicting conclusions concerning the roles of particular design elements. We argue that this may largely be due to insufficient characterizations of multimodal design itself. To achieve tighter control of this potential source of variation, we present a multimodal descriptive annotation framework drawing on multimodal (cohesive) film discourse analysis. This framework is seen as a critical first step toward being able to highlight just those differences in design that have functional consequences. For such consequences to accrue, however, viewers need to attend differently to corresponding design differences. The goal of the current paper, therefore, is to use eye-tracking techniques to explore the extent to which discourse structures revealed by our analytic framework relate to recipients' attention allocation. We hypothesize that any potentially emerging anomalies in regards to discourse organization, such as instances of unsuccessful cohesion signaling, may have correlations in the behavioral data. We report our current state of development for performing this kind of multimodal cohesion analysis and some of the unresolved challenges raised when considering how such analyses may be related to performance data

Heavy-quark mass effects in Higgs boson production at the LHC

We study the impact of heavy-quark masses in Higgs boson production through gluon fusion at the LHC. We extend previous computations of the fully differential cross section and of the transverse momentum spectrum of the Higgs boson by taking into account the finite top- and bottom-quark masses up to O(alpha_S^3). We also discuss the issues arising when the heavy-quark mass is much smaller than the Higgs mass. Our results are implemented in updated versions of the HNNLO and HRes numerical programs.Comment: Minor modifications, results unchanged. Discussion on uncertainties added. Version published on JHE

Olfactory and Gustatory Dysfunction in Patients With Autoimmune Encephalitis

Objective: To test the hypothesis that olfactory (OF) and gustatory function (GF) is disturbed in patients with autoimmune encephalitides (AE). Methods: The orthonasal OF was tested in 32 patients with AE and 32 age- and sex-matched healthy controls (HC) with the standardized Threshold Discrimination Identification (TDI) score. This validated olfactory testing method yields individual scores for olfactory threshold (T), odor discrimination (D), and identification (I), along with a composite TDI score. The GF was determined by the Taste Strip Test (TST). Results: Overall, 24/32 (75%) of patients with AE, but none of 32 HC (p < 0.001) had olfactory dysfunction in TDI testing. The results of the threshold, discrimination and identification subtests were significantly reduced in patients with AE compared to HC (all p < 0.001). Assessed by TST, 5/19 (26.3%) of patients with AE, but none of 19 HC presented a significant limitation in GF (p < 0.001). The TDI score was correlated with the subjective estimation of the olfactory capacity on a visual analog scale (VAS; r(s) = 0.475, p = 0.008). Neither age, sex, modified Rankin Scale nor disease duration were associated with the composite TDI score. Conclusions: This is the first study investigating OF and GF in AE patients. According to unblinded assessment, patients with AE have a reduced olfactory and gustatory capacity compared to HC, suggesting that olfactory and gustatory dysfunction are hitherto unrecognized symptoms in AE. Further studies with larger number of AE patients would be of interest to verify our results

Atomistic defect states as quantum emitters in monolayer MoS2_2

Quantum light sources in solid-state systems are of major interest as a basic ingredient for integrated quantum device technologies. The ability to tailor quantum emission through deterministic defect engineering is of growing importance for realizing scalable quantum architectures. However, a major difficulty is that defects need to be positioned site-selectively within the solid. Here, we overcome this challenge by controllably irradiating single-layer MoS$_{2}$ using a sub-nm focused helium ion beam to deterministically create defects. Subsequent encapsulation of the ion bombarded MoS$_{2}$ flake with high-quality hBN reveals spectrally narrow emission lines that produce photons at optical wavelengths in an energy window of one to two hundred meV below the neutral 2D exciton of MoS$_{2}$. Based on ab-initio calculations we interpret these emission lines as stemming from the recombination of highly localized electron-hole complexes at defect states generated by the helium ion bombardment. Our approach to deterministically write optically active defect states in a single transition metal dichalcogenide layer provides a platform for realizing exotic many-body systems, including coupled single-photon sources and exotic Hubbard systems.Comment: Main: 9 pages, 3 figures + SI: 19 pages, 10 figure

Essential role of glucose transporter GLUT3 for post-implantation embryonic development

Deletion of glucose transporter gene Slc2a3 (GLUT3) has previously been reported to result in embryonic lethality. Here, we define the exact time point of growth arrest and subsequent death of the embryo. Slc2a3−/− morulae and blastocysts developed normally, implanted in vivo, and formed egg-cylinder-stage embryos that appeared normal until day 6·0. At day 6·5, apoptosis was detected in the ectodermal cells of Slc2a3−/− embryos resulting in severe disorganization and growth retardation at day 7·5 and complete loss of embryos at day 12·5. GLUT3 was detected in placental cone, in the visceral ectoderm and in the mesoderm of 7·5-day-old wild-type embryos. Our data indicate that GLUT3 is essential for the development of early post-implanted embryos