Influence of the heterointerface sharpness on exciton recombination dynamics in an ensemble of (In,Al)As/AlAs quantum dots with indirect band-gap

The dynamics of exciton recombination in an ensemble of indirect band-gap (In,Al)As/AlAs quantum dots with type-I band alignment is studied. The lifetime of confined excitons which are indirect in momentum-space is mainly influenced by the sharpness of the heterointerface between the (In,Al)As quantum dot and the AlAs barrier matrix. Time-resolved photoluminescence experiments and theoretical model calculations reveal a strong dependence of the exciton lifetime on the thickness of the interface diffusion layer. The lifetime of excitons with a particular optical transition energy varies because this energy is obtained for quantum dots differing in size, shape and composition. The different exciton lifetimes, which result in photoluminescence with non-exponential decay obeying a power-law function, can be described by a phenomenological distribution function, which allows one to explain the photoluminescence decay with one fitting parameter only.Comment: 10 pages, 7 figure

Body image, cosmesis, quality of life, and functional outcome of hand-assisted laparoscopic versus open restorative proctocolectomy: long-term results of a randomized trial

BACKGROUND: This study aimed to compare quality of life (QOL), functional outcome, body image, and cosmesis after hand-assisted laparoscopic (LRP) versus open restorative proctocolectomy (ORP). The potential long-term advantages of LRP over ORP remain to be determined. The most likely advantage of LRP is the superior cosmetic result. It is, however, unclear whether the size and location of incisions affect body image and QOL. METHODS: In a previously conducted randomized trial comparing LRP with ORP, 60 patients were prospectively evaluated. The primary end points were body image and cosmesis. The secondary end points were morbidity, QOL, and functional outcome. A body image questionnaire was used to evaluate body image and cosmesis. The Short Form-36 Health Survey and the Gastrointestinal Quality of Life Inventory were used to assess QOL. Body image and QOL also were assessed preoperatively. RESULTS: A total of 53 patients completed the QOL and functional outcome questionnaires. There were no differences in functional outcome, morbidity, or QOL between LRP and ORP. At a median of 2.7 years after surgery, 46 patients returned the questionnaires regarding body image, cosmesis, and morbidity. The body image and cosmesis scores of female patients were significantly higher in the LRP group than in the ORP group (body image, 17.4 vs 14.9; cosmesis, 19.1 vs 13.0, respectively). The female patients in the ORP group had significantly lower body image scores than the male patients (14.9 vs 18.3). CONCLUSIONS: This study is the first to show that ORP has a negative impact on body image and cosmesis as compared with LRP. Functional outcome, QOL, and morbidity are similar for the two approaches. The advantages of a long-lasting improved body image and cosmesis for this relatively young patient population may compensate for the longer operating times and higher costs, particularly for wome

The Supremum Norm of the Discrepancy Function: Recent Results and Connections

A great challenge in the analysis of the discrepancy function D_N is to obtain universal lower bounds on the L-infty norm of D_N in dimensions d \geq 3. It follows from the average case bound of Klaus Roth that the L-infty norm of D_N is at least (log N) ^{(d-1)/2}. It is conjectured that the L-infty bound is significantly larger, but the only definitive result is that of Wolfgang Schmidt in dimension d=2. Partial improvements of the Roth exponent (d-1)/2 in higher dimensions have been established by the authors and Armen Vagharshakyan. We survey these results, the underlying methods, and some of their connections to other subjects in probability, approximation theory, and analysis.Comment: 15 pages, 3 Figures. Reports on talks presented by the authors at the 10th international conference on Monte Carlo and Quasi-Monte Carlo Methods in Scientific Computing, Sydney Australia, February 2011. v2: Comments of the referee are incorporate

Widespread recombination, reassortment, and transmission of unbalanced compound viral genotypes in natural arenavirus infections.

Arenaviruses are one of the largest families of human hemorrhagic fever viruses and are known to infect both mammals and snakes. Arenaviruses package a large (L) and small (S) genome segment in their virions. For segmented RNA viruses like these, novel genotypes can be generated through mutation, recombination, and reassortment. Although it is believed that an ancient recombination event led to the emergence of a new lineage of mammalian arenaviruses, neither recombination nor reassortment has been definitively documented in natural arenavirus infections. Here, we used metagenomic sequencing to survey the viral diversity present in captive arenavirus-infected snakes. From 48 infected animals, we determined the complete or near complete sequence of 210 genome segments that grouped into 23 L and 11 S genotypes. The majority of snakes were multiply infected, with up to 4 distinct S and 11 distinct L segment genotypes in individual animals. This S/L imbalance was typical: in all cases intrahost L segment genotypes outnumbered S genotypes, and a particular S segment genotype dominated in individual animals and at a population level. We corroborated sequencing results by qRT-PCR and virus isolation, and isolates replicated as ensembles in culture. Numerous instances of recombination and reassortment were detected, including recombinant segments with unusual organizations featuring 2 intergenic regions and superfluous content, which were capable of stable replication and transmission despite their atypical structures. Overall, this represents intrahost diversity of an extent and form that goes well beyond what has been observed for arenaviruses or for viruses in general. This diversity can be plausibly attributed to the captive intermingling of sub-clinically infected wild-caught snakes. Thus, beyond providing a unique opportunity to study arenavirus evolution and adaptation, these findings allow the investigation of unintended anthropogenic impacts on viral ecology, diversity, and disease potential

A estrutura dos mitos no pensamento freudiano: das origens da cena analítica à cena das origens:

This article seeks to explain the axes that structure a theory of myth since the beginnings of Freudian thought, in order to comprehend the conditions for the methodological twist present in the theses of Totem and Taboo. The category of myth operates both as a privileged resource for anthropological anchoring to the construction of a theory of the unconscious and as a method for apprehending the limits of this same knowledge. We demonstrate how the emergence of the psychoanalysis would be tributary of this movement and how an epistemological isonomy was the basis for the myth of the primeval horde.Este artículo busca explicar los ejes estructurales de la teoría del mito presente desde los inicios del pensamiento freudiano, con miras a una comprensión amplia de las condiciones de posibilidad del doble giro metodológico presente en Tótem y Tabú. La categoría de mito opera tanto como un recurso privilegiado para el anclaje antropológico a la construcción de una teoría del inconsciente como un método para aprehender los límites de este mismo conocimiento. Demostramos cómo la emergencia de la escena psicoanalítica sería tributaria de este movimiento y cómo una isonomía epistemológica fue la base del mito de la horda primitiva.O presente artigo busca explicitar os eixos que estruturam uma teoria do mito latente desde os primórdios do pensamento freudiano, com vistas a uma compreensão ampla das condições de possibilidade da dupla torção metodológica presente nas teses de Totem e Tabu.  A categoria de mito opera tanto como recurso privilegiado de ancoragem antropológica à construção de uma teoria do inconsciente, quanto de um método de apreensão dos limites deste mesmo saber. Demonstramos como a emergência da cena psicanalítica seria tributária desse movimento e como uma isonomia epistemológica foi a base para o mito da horda primeva

The N-terminal intrinsically disordered domain of mgm101p is localized to the mitochondrial nucleoid.

The mitochondrial genome maintenance gene, MGM101, is essential for yeasts that depend on mitochondrial DNA replication. Previously, in Saccharomyces cerevisiae, it has been found that the carboxy-terminal two-thirds of Mgm101p has a functional core. Furthermore, there is a high level of amino acid sequence conservation in this region from widely diverse species. By contrast, the amino-terminal region, that is also essential for function, does not have recognizable conservation. Using a bioinformatic approach we find that the functional core from yeast and a corresponding region of Mgm101p from the coral Acropora millepora have an ordered structure, while the N-terminal domains of sequences from yeast and coral are predicted to be disordered. To examine whether ordered and disordered domains of Mgm101p have specific or general functions we made chimeric proteins from yeast and coral by swapping the two regions. We find, by an in vivo assay in S.cerevisiae, that the ordered domain of A.millepora can functionally replace the yeast core region but the disordered domain of the coral protein cannot substitute for its yeast counterpart. Mgm101p is found in the mitochondrial nucleoid along with enzymes and proteins involved in mtDNA replication. By attaching green fluorescent protein to the N-terminal disordered domain of yeast Mgm101p we find that GFP is still directed to the mitochondrial nucleoid where full-length Mgm101p-GFP is targeted

Spin-flip Raman scattering of the Γ\Gamma-X mixed exciton in indirect band-gap (In,Al)As/AlAs quantum dots

The band structure of type-I (In,Al)As/AlAs quantum dots with band gap energy exceeding 1.63 eV is indirect in momentum space, leading to long-lived exciton states with potential applications in quantum information. Optical access to these excitons is provided by mixing of the $\Gamma$- and X-conduction band valleys, from which control of their spin states can be gained. This access is used here for studying the exciton spin-level structure by resonant spin-flip Raman scattering, allowing us to accurately measure the anisotropic hole and isotropic electron $g$ factors. The spin-flip mechanisms for the indirect exciton and its constituents as well as the underlying optical selection rules are determined. The spin-flip intensity is a reliable measure of the strength of $\Gamma$-X-valley mixing, as evidenced by both experiment and theory.Comment: 5 pages, 3 figure

Tight regulation of unstructured proteins: from transcript synthesis to protein degradation

Altered abundance of several intrinsically unstructured proteins ( IUPs) has been associated with perturbed cellular signaling that may lead to pathological conditions such as cancer. Therefore, it is important to understand how cells precisely regulate the availability of IUPs. We observed that regulation of transcript clearance, proteolytic degradation, and translational rate contribute to controlling the abundance of IUPs, some of which are present in low amounts and for short periods of time. Abundant phosphorylation and low stochasticity in transcription and translation indicate that the availability of IUPs can be finely tuned. Fidelity in signaling may require that most IUPs be available in appropriate amounts and not present longer than needed.Royal Society; MRC Special Training Fellowship; Medical Research Council [MC_U105161047, MC_U105185859, G0600158]info:eu-repo/semantics/publishedVersio

Bayesian statistical modelling of human protein interaction network incorporating protein disorder information

<p>Abstract</p> <p>Background</p> <p>We present a statistical method of analysis of biological networks based on the exponential random graph model, namely p2-model, as opposed to previous descriptive approaches. The model is capable to capture generic and structural properties of a network as emergent from local interdependencies and uses a limited number of parameters. Here, we consider one global parameter capturing the density of edges in the network, and local parameters representing each node's contribution to the formation of edges in the network. The modelling suggests a novel definition of important nodes in the network, namely <it>social</it>, as revealed based on the local <it>sociality </it>parameters of the model. Moreover, the sociality parameters help to reveal organizational principles of the network. An inherent advantage of our approach is the possibility of hypotheses testing: <it>a priori </it>knowledge about biological properties of the nodes can be incorporated into the statistical model to investigate its influence on the structure of the network.</p> <p>Results</p> <p>We applied the statistical modelling to the human protein interaction network obtained with Y2H experiments. Bayesian approach for the estimation of the parameters was employed. We deduced <it>social </it>proteins, essential for the formation of the network, while incorporating into the model information on protein disorder. <it>Intrinsically disordered </it>are proteins which lack a well-defined three-dimensional structure under physiological conditions. We predicted the fold group (ordered or disordered) of proteins in the network from their primary sequences. The network analysis indicated that protein disorder has a positive effect on the connectivity of proteins in the network, but do not fully explains the interactivity.</p> <p>Conclusions</p> <p>The approach opens a perspective to study effects of biological properties of individual entities on the structure of biological networks.</p