Equivalence of cost generators for minimum cost flow phase unwrapping.

Phase unwrapping represents a crucial step in processing phase data obtained with techniques such as synthetic aperture radar interferometry, speckle interferometry, and magnetic resonance imaging. The so-called branch-cut approaches form an important class of phase unwrapping algorithms. In 1996, Costantini proposed to transform the problem of correctly placing branch cuts into a minimum cost flow problem [Proceedings of the Fringe '96 Workshop (European Space Agency, Munich, 1996), pp. 261-272]. The critical point of this new approach is to generate cost functions that have to represent all the a priori knowledge necessary for phase unwrapping. Any function transforming a priori knowledge into a cost function is called a cost generator. Several types of algorithms ranging from heuristic approaches to generators based on probability-theory interpretations were suggested. A problem arising from the growing diversity of algorithms is to find a criterion for the equivalence of different cost generators. Two cost generators are equivalent if they produce cost functions with the same minimal flow for every residue configuration on every image with all possible a priori knowledge. Comparing the results of different cost generators on test scenes can show only their non-equivalence. We solve this problem by proving the following mathematical classification theorem: Two cost generators are equivalent if and only if one can be transformed into the other by multiplication by a fixed constant.     

The contribution of metamemory deficits to schizophrenia.

A number of recent studies have demonstrated that individuals with schizophrenia display knowledge corruption; that is, they hold false information with strong conviction. This aberration in metamemory is thought to stem from poor memory accuracy in conjunction with impaired discrimination of correct and incorrect judgments in terms of confidence. Thirty-one participants with schizophrenia, along with 61 healthy control participants and 48 control participants with other psychiatric conditions, participated in a computerized source memory task. Whereas no differences in memory accuracy were observed between the group with schizophrenia and the group with other psychiatric diagnoses, knowledge corruption was specifically impaired in those with schizophrenia. Schizophrenia participants showed a significantly decreased confidence gap: They were more confident in errors and less confident in correct responses relative to those in the control groups. Knowledge corruption is theorized to be a potential risk factor for the emergence of delusions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Routine immunization of infants in the Canton of Zurich

At present there is a shortage of data regarding the rate of routine immunization in Swiss children. To address this deficit, a representative cross sectional study was conducted in the Canton of Zurich with 210 children aged between 24 and 36 months. Data was taken from the individual official vaccination certificates. 178 vaccination certificates (55.1% female and 44.9% male) were evaluated, corresponding to a response rate of 84.8%. With children of foreign nationalities, the response rate was 66.7%, whereas the response rate of Swiss children was 90.6% (p < 0.001). The response rate of children of a European nationality outside the European Union was especially poor (33.3%). The immunization rate with three doses of diphtheria, tetanus and poliomyelitis vaccines was 99.4%, and that of the pertussis vaccine was 93.3%. With the vaccines for measles, mumps and rubella the rates were 80.3%, 78.1% and 77.5% respectively. Vaccination rate against Haemophilus influenzae type B was 74.7% with two doses, and 61.2% with three doses. The timing and the number of doses of the vaccines used for infants in the Canton of Zurich were satisfactory. However, the vaccination rate for measles, mumps and rubella is inadequate. Attention should be paid to this problem and also to possible insufficient care of foreign children.     

Combination of Surface Charge and Size Controls the Cellular Uptake of Functionalized Graphene Sheets

A fundamental issue for biomedical applications of graphene is the correlation between its physicochemical properties and cellular uptake mechanism. However, such studies are challenging due to the intrinsic polydispersity of graphene. In this work, a series of water soluble graphene sheets with the same polymer coverage, density of functional groups, and fluorescence intensity but three different sizes and surface charges are produced. The effect of the latter two factors and their combination on the mechanism of cellular uptake and intracellular pathways of these defined nanosheets is investigated via confocal and Raman microscopies. While positively (? NH₃⁺) and negatively (? OSO₃^?) charged sheets show an energy dependent uptake, their neutral analogs do not show any significant uptake. The cellular uptake efficacy of positively charged graphene sheets is independent of the size and occurs both through phagocytosis and clathrin‐mediated endocytosis pathways. However, cellular uptake efficacy of graphene sheets with negative surface charge strongly depends on the size of the sheets. They cross the membrane mainly through phagocytosis and sulfate‐receptor‐mediated endocytosis. This study demonstrates that the impact of the size of graphene derivatives on their cellular uptake pathways highly depends on their surface charges and vice versa.     

Nanostructured Si/Organic Heterojunction Solar Cells with High Open‐Circuit Voltage via Improving Junction Quality

Nanostructured silicon (Si) can provide improved light harvest efficiencies in organic‐Si heterojunction solar cells due to its low light reflection ratio compared with planar one. However, the associated large surface/volume ratio of nanostructured Si suffers from serious surface recombination as well as poor adhesion with organics in organic‐Si heterojunction solar cells, which leads to an inferior open‐circuit voltage (V_oc). Here, we develop a simple and effective method to suppress charge recombination as well as enhancing adhesion force between nanostructured Si and organics by incorporating a silane chemical, namely 3‐glycidoxypropyltrimethoxydsilane (GOPS). GOPS can chemically graft onto nanostructured Si and improve the aqueous organic wetting properties, suppressing surface charge recombination velocity dramatically. In addition, this chemically grafted layer can enhance adhesion force between organics and Si. In such a way, a record V_oc of 640 mV associated with a power conversion efficiency of 14.1% is obtained for organic‐nanostructured Si heterojunction devices. These findings suggest a promising approach to low‐cost and simple fabrication for high‐performance organic‐Si solar cells.     

Zum Tragverhalten von Stützen semi‐integraler Brücken

Load‐bearing behaviour of columns of integral bridges – realistic calculation of columns of integral bridges for the ultimate limit state Due to the complex and interactive load‐bearing behaviour, calculation of integral bridges is more expensive than the calculation of bridges with its superstructure uncoupled from the substructure. Apparently conservatively chosen reinforcement ratios lead to increased stiffness of the columns and thus inherently increased the constraining forces. Therefore, a greater reinforcement ratio is not imperatively connected with a better load‐bearing behaviour of the columns. To better understand the load‐bearing behavior of integral bridges, it is necessary to consider the physical non‐linearity in the calculation. In this contribution, the non‐linear behaviour of integral columns is examined by varying the cross section dimensions and the reinforcement ratios. The results are analyzed with regard to the columns ductility and the constraining forces. Finally, this contribution offers conceptual proposals, which can be used for the dimensioning of integral bridges.