Cascading Gravity and Degravitation

We construct a cascading brane model of gravity in which the behavior of the gravitational force law interpolates from (n+4)-dimensional to (n+3)-dimensional all the way down to 4-dimensional from longer to shorter length scales. We show that at the linearized level, this model exhibits the features necessary for degravitation of the cosmological constant. The model is shown to be ghost free with the addition of suitable brane kinetic operators, and we demonstrate this using a number of independent procedures. Consequently this is a consistent IR modification of gravity, providing a promising framework for a dynamical, degravitating solution of the cosmological constant problem.Comment: 31 pages, 1 figur

Development cooperation and non-state armed groups

As CPU chips integrate more processor cores, computer systems are evolving from multi-core to many-core. How to utilize them fully and efficiently is a great challenge. With message passing and native support of concurrent programming, Erlang is a convenient way of developing applications on these systems. The scalability of applications is dependent on the performance of the underlying Erlang runtime system or virtual machine (VM). This thesis presents a study on the scalability of the Erlang VM on a many-core processor with 64 cores, TILEPro64. The purpose is to study the implementation of parallel Erlang VM, investigate its performance, identify bottlenecks and provide optimization suggestions. To achieve this goal, the VM is tested with some benchmark programs. Then discovered problems are examinedmore closely with methods such as profiling and tracing. The results show that the current version of Erlang VM achieves good scalability on the processor with most benchmarks used. The maximum speedup is from about 40 to 50 on 60 cores. Synchronization overhead caused by contention is a major bottleneck of the system. The scalability can be improved by reducing lock contention. Another major problem is that the parallel version of the virtual machine using one core is much slower than the sequential version with a benchmark program containing a huge amount of message passing. Further analysis indicates that synchronization latency induced by uncontended locks is one of the main reasons. Low overhead locks, lock-free structures or algorithms are recommended for improving the performance of the Erlang VM. Our evaluation result suggests Erlang is ready to be used to develop applications on many-core systems

Development cooperation and non-state armed groups

Die vorliegende Studie ist das Ergebnis eines Forschungsvorhabens des Deutschen Instituts für Entwicklungspolitik (DIE). Ziel der Studie ist es, zu einem besseren Verständnis des Themas beizutragen und zu helfen, sowohl die Reaktionsfähigkeit der entwicklungspolitischen Akteure in Bezug auf non-state armed groups/nichtstaatliche Gewaltakteure (NSAG) in Krisensituationen als auch ihre Möglichkeiten im Umgang mit NSAG zur Konfliktbearbeitung zu verbessern. Hintergrund des Forschungsvorhabens sind Situationen gewalttätiger Auseinandersetzungen, mit denen Entwicklungspolitik in vielen Ländern und Regionen konfrontiert ist. Nichtstaatliche bewaffnete Gruppierungen sind ein Hauptmerkmal innerstaatlicher Konflikte und vieler regionaler Kriege. Typische Erscheinungsformen nichtstaatlicher Gewaltakteure sind Rebellenarmeen, Kriegsherren oder Terroristen. Unter NSAG werden im Rahmen der vorliegenden Untersuchung Gruppen verstanden, die durch ihr Handeln das Gewaltmonopol des Staates in Frage stellen. "Interaktion" oder "Umgang" mit NSAG bedeutet im Sinne der vorliegenden Studie ausschließlich ein reflektiertes Vorgehen gegenüber diesen Gruppen. Interaktion ist also nicht gleichbedeutend mit "Kooperation" oder der expliziten oder impliziten Anerkennung oder Legitimierung von Zielen oder Methoden einer NSAG. (ICD2

Inflammatory Bowel Diseases: When Natural Friends Turn into Enemies—The Importance of CpG Motifs of Bacterial DNA in Intestinal Homeostasis and Chronic Intestinal Inflammation

From numerous studies during the last years it became evident that bacteria and bacterial constituents play a decisive role both in the maintenance of intestinal immune homeostasis as well as in the development and perpetuation of chronic intestinal inflammation. In this review we focus on the role of bacterial DNA which is a potent immunomodulatory component of the bacterial flora. Bacterial DNA has been shown to be protective against experimental colitis. In contrast bacterial DNA essentially contributes to the perpetuation of an already established chronic intestinal inflammation in a Toll-like receptor (TLR)9-dependent manner. This dichotomic action may be explained by a different activation status of essential regulators of TLR signaling like Glycogen synthase kinase 3-β (GSK3-β) depending on the pre-activation status of the intestinal immune system. In this review we suggest that regulators of TLR signaling may be interesting therapeutic targets in IBD aiming at the restoration of intestinal immune homeostasis

Transition from low-threshold vocational education and training to work in Switzerland: factors influencing objective and subjective career success

Context: There are currently two low-threshold vocational education and training (VET) options in Switzerland for young people at risk: A two-year programme for a Federal VET certificate and a practical training programme designed for young people with special needs. In the present study, we looked at transitions from these programmes to the labour market. Possible influences on objective and subjective indicators of career success, such as social background, personal disposition, and training, were considered. Methods: Data were collected from 418 apprentices in the French- and German-speaking parts of Switzerland at three measurement points: t1, at the beginning of training; t2, upon completion of training; and t3, 10 months later. Participants responded to a written questionnaire. Findings: Ten months after completing their apprenticeships, the majority of participating young people were either employed or continuing their education. Results of the multinomial logistic and linear regressions showed a differentiated, rather than uniform, picture depending on the criteria for career success. The background factors of gender and school (9th grade) were associated with objective success after the apprenticeship ended but not with subjective career success (hypothesis 1). For the variables concerning person disposition and agency (hypothesis 2), we found two plausible associations: A positive attitude towards life helped with unemployment avoidance and a highly self-rated school performance was associated with later satisfaction. As predicted in hypothesis 3, situational factors related to the VET company and school showed a number of significant but sometimes weak associations with objective and subjective career success. Additionally, competencies and support of VET trainers related to continuance in the learned profession. Conclusions: The career development paths of young people are influenced by various background and personality factors, as well as the training situation. VET trainers should be aware of their crucial role and understand how their interventions affect apprentices’ self-perceptions and perceptions of their learned professions, which consequently influence their motivations and career aspirations. The situation at the VET school (as a learning and social place) is equally important, especially because of the aim to increase permeability for further training. Young people not in employment, education or training (NEET) are of particular concern. Even though this group is smaller in Switzerland than in most other countries, a number of problematic symptoms can be detected during apprenticeship that point to the need for the prevention of a later NEET status. (DIPF/Orig.

Size tunable visible and near-infrared photoluminescence from vertically etched silicon quantum dots

Corrugated etching techniques were used to fabricate size-tunable silicon quantum dots that luminesce under photoexcitation, tunable over the visible and near infrared. By using the fidelity of lithographic patterning and strain limited, self-terminating oxidation, uniform arrays of pillar containing stacked quantum dots as small as 2 nm were patterned. Furthermore, an array of pillars, with multiple similar sized quantum dots on each pillar, was fabricated and tested. The photoluminescence displayed a multiple, closely peaked emission spectra corresponding to quantum dots with a narrow size distribution. Similar structures can provide quantum confinement effects for future nanophotonic and nanoelectronic devices

Cascading DGP

We present a higher codimension generalization of the DGP scenario which, unlike previous attempts, is free of ghost instabilities. The 4D propagator is made regular by embedding our visible 3-brane within a 4-brane, each with their own induced gravity terms, in a flat 6D bulk. The model is ghost-free if the tension on the 3-brane is larger than a certain critical value, while the induced metric remains flat. The gravitational force law `cascades' from a 6D behavior at the largest distances followed by a 5D and finally a 4D regime at the shortest scales.Comment: 4 pages; one reference added and a typo correcte

Gender, Family, and Community Attachment in a New Destination

As new immigrant destinations in the USA have become home to more settled immigrant populations, they are also becoming less male-dominated and attracting more women and families. But this process is occurring unevenly, with some new destinations much more attractive to women than others. The factors that might lead a destination to attract or retain women are not well understood. We draw on interviews with long-time Latin American residents in a non-metropolitan community in Utah with a fairly high proportion of women immigrants to analyze the ways in which gender and other factors relate to community attachment in this specific context. We examine gender differences in satisfaction with the community and experiences of discrimination and plans to remain in the community. Surprisingly, given current anti-immigrant trends in national politics, we found high levels of community attachment among both men and women. Although experiences of racism were common in our sample, many of the respondents were quick to downplay these experiences and focused instead on their overall positive assessment of the community. Women were more attuned to the experience of discrimination and less willing to downplay it. They were also less likely to have a long-term plan to remain in the community, but this appeared to be more related to their consideration of other family members’ long-term plans, rather than due to their experiences of discrimination. These findings have implications for understanding gendered settlement patterns as well as for promoting immigrant integration at the local level in an unfavorable political context