A thin ring model for the OH megamaser in IIIZw35

We present a model for the OH megamaser emission in the starburst galaxy IIIZw35. The observed diffuse and compact OH maser components in this source are explained by a single phase of unsaturated clumpy gas distributed in a thin ring structure and amplifying background continuum. We emphasize the importance of clumpiness in the OH masing medium, an effect that has not been fully appreciated previously. The model explains why multiple bright spots are seen only at the ring tangents while smoother emission is found elsewhere. Both the observed velocity gradients and the line to continuum ratios around the ring enquire a geometry where most of the seed photons come from a continuum emission which lies outside the OH ring. To explain both the OH and continuum brightness, free-free absorbing gas is required along the ring axis to partially absorb the far side of the ring. It is proposed that the required geometry arises from an inwardly propagating ring of starburst activity

Assessment of National Natural Resources Policies Implementation in Kilimanjaro Region, Tanzania

The Kilimanjaro landscape provides a range of ecosystem services such as water, local climate modification, tourism and support of local livelihoods. Land degradation has, however, seriously threatened the landscape ability in providing these services, leading to decreased land productivity This paper is based on a study conducted in Kilimanjaro region to provide an understanding of how effectively natural resources-related policies are implemented by land users, and how they practically guide sustainable land management. Data collection involved interviews with purposively selected progressive farmers using a structured questionnaire, in-depth interviews with key informants, mainly district officials, NGOs and CBOs representatives and focus group discussions, as well as review of relevant literature. Quantitative data were analysed using SPSS, while qualitative data were triangulated using content analysis. Findings indicated that there are several policies related to natural resource management that are both cross-cutting and cross-sectoral in nature. While majority of respondents were aware of the various policies, male respondents were more aware than females, influenced by customary male dominance in natural resource issues. The policies are implemented at various levels, taking different forms and involve various stakeholders, including individuals, groups, NGOs, CBOs and public institutions. Generally, communities are actively participating in SLM activities though influenced by several pull and push factors in policy implementation in the area. The paper argues that for effective implementation of the natural resources policies there is a need to review and harmonise the sectoral policies with changing internal and external conditions such as economic transformation, globalization and climate change.

Assessment of the Extent to which Productive Sector Policies Mainstream Sustainable Land Management Principles

This paper provides an assessment of the extent to which productive sector policies mainstream sustainable land management (SLM) principles and suggests how mainstreaming of these principles could be strengthened and be more effective in Kilimanjaro region. Primary data was collected using qualitative methods including in-depth interviews with key informants and focus group discussions. Key informants included government officials, SLM project staff, NGOs and representatives of communities. Secondary data was gathered from review of relevant literature including government policies, strategies, project documents and other research materials. The data collected were analysed using content analysis and synthesised to determine the extent to which the productive sector policies mainstream sustainable land management principles. Findings indicate that several relevant NRM sectors have mainstreamed SLM principles, namely improved land productivity, improved livelihood and improved ecosystems. The degree to which these policies have mainstreamed SLM principles vary from adequately, moderately, and slightly. Despite the reported degree of mainstreaming the SLM principles in sector polices several challenges undermine the process, including land scarcity, land tenure, inadequate enforcement of policies, land use conflicts, human and financial resources constraints, and climate change. Various stakeholders are involved in SLM initiatives, ranging from local communities to international organisations. The diversity of stakeholders requires well coordinated efforts so as to maximise synergies and complementarities between the various actors. Also more effort has to be done at policy level to ensure that all sector policies adequately address sustainability in natural resources management to ensure that land productivity, livelihoods and ecosystems are improved.

Granular Solid Hydrodynamics

Granular elasticity, an elasticity theory useful for calculating static stress distribution in granular media, is generalized to the dynamic case by including the plastic contribution of the strain. A complete hydrodynamic theory is derived based on the hypothesis that granular medium turns transiently elastic when deformed. This theory includes both the true and the granular temperatures, and employs a free energy expression that encapsulates a full jamming phase diagram, in the space spanned by pressure, shear stress, density and granular temperature. For the special case of stationary granular temperatures, the derived hydrodynamic theory reduces to {\em hypoplasticity}, a state-of-the-art engineering model.Comment: 42 pages 3 fi

Universal fluctuations in subdiffusive transport

Subdiffusive transport in tilted washboard potentials is studied within the fractional Fokker-Planck equation approach, using the associated continuous time random walk (CTRW) framework. The scaled subvelocity is shown to obey a universal law, assuming the form of a stationary Levy-stable distribution. The latter is defined by the index of subdiffusion alpha and the mean subvelocity only, but interestingly depends neither on the bias strength nor on the specific form of the potential. These scaled, universal subvelocity fluctuations emerge due to the weak ergodicity breaking and are vanishing in the limit of normal diffusion. The results of the analytical heuristic theory are corroborated by Monte Carlo simulations of the underlying CTRW

Restoration of supersymmetric Slavnov-Taylor and Ward identities in presence of soft and spontaneous symmetry breaking

Supersymmetric Slavnov-Taylor and Ward identities are investigated in presence of soft and spontaneous symmetry breaking. We consider an abelian model where soft supersymmetry breaking yields a mass splitting between electron and selectron and triggers spontaneous symmetry breaking, and we derive corresponding identities that relate the electron and selectron masses with the Yukawa coupling. We demonstrate that the identities are valid in dimensional reduction and invalid in dimensional regularization and compute the necessary symmetry-restoring counterterms.Comment: 35 pages, LaTeX, 9 postscript figure

A comparison of twin birthweight data from Australia, the Netherlands, the United States, Japan and South Korea: are genetic and environmental variations in birthweight similar in Caucasians and East Asians?

Birthweight has implications for physical and mental health in later life. Using data from Caucasian twins collected in Australia, the Netherlands and the United States, and from East Asian twins collected in Japan and South Korea, we compared the total phenotypic, genetic and environmental variances of birthweight between Caucasians and East Asians. Model-fitting analyses yielded four major findings. First, for both males and females, the total phenotypic variances of birthweight were about 45% larger in Caucasians than in East Asians. The larger phenotypic variances were mainly attributable to a greater shared environmental variance of birthweight in Caucasians (ranging from 62% to 67% of variance) than Asians (48% to 53%). Second, the genetic variance of birthweight was equal in Caucasians and East Asians for both males and females, explaining a maximum of 17% of variance. Third, small variations in total phenotypic variances of birthweight within Caucasians and within East Asians were mainly due to differences in nonshared environmental variances. We speculate that maternal effects (both genetic and environmental) explain the large shared environmental variance in birthweight and may account for the differences in phenotypic variance in birthweight between Caucasians and East Asians. Recent molecular findings and specific environmental factors that are subsumed by maternal effects are discussed

Leading strategies in competitive on-line prediction

We start from a simple asymptotic result for the problem of on-line regression with the quadratic loss function: the class of continuous limited-memory prediction strategies admits a "leading prediction strategy", which not only asymptotically performs at least as well as any continuous limited-memory strategy but also satisfies the property that the excess loss of any continuous limited-memory strategy is determined by how closely it imitates the leading strategy. More specifically, for any class of prediction strategies constituting a reproducing kernel Hilbert space we construct a leading strategy, in the sense that the loss of any prediction strategy whose norm is not too large is determined by how closely it imitates the leading strategy. This result is extended to the loss functions given by Bregman divergences and by strictly proper scoring rules.Comment: 20 pages; a conference version is to appear in the ALT'2006 proceeding

Exhaustion of the CD8+ T cell compartment in patients with mutations in phosphoinositide 3-kinase delta

Pathogenic gain-of-function mutations in the gene encoding phosphoinositide 3-kinase delta (PI3Kδ) cause activated PI3Kδ syndrome (APDS), a disease characterized by humoral immunodeficiency, lymphadenopathy, and an inability to control persistent viral infections including Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infections. Understanding the mechanisms leading to impaired immune response is important to optimally treat APDS patients. Immunosenescence of CD8+ T cells was suggested to contribute to APDS pathogenesis. However, the constitutive activation of T cells in APDS may also result in T cell exhaustion. Therefore, we studied exhaustion of the CD8+ T cell compartment in APDS patients and compared them with healthy controls and HIV patients, as a control for exhaustion. The subset distribution of the T cell compartment of APDS patients was comparable with HIV patien