Magnetic Bound States in Dimerized Quantum Spin Systems

Magnetic bound states are a general phenomenon in low dimensional antiferromagnets with gapped singlet states. Using Raman scattering on three compounds as dedicated examples we show how exchange topology, dimensionality, defects and thermal fluctuations influence the properties and the spectral weight of these states.Comment: 3 pages, 1 figure, proceedings of the SCES'98, Paris, to be published in Physica

Dopant-Bound Spinons in Cu_(1-x)Zn_xGeO_3

Polarized inelastic light scattering experiments on Cu_(1-x)Zn_xGeO_3 (0<= x 0 a new distinct mode at nearly half the energy of the singlet response below the spin-Peierls transition. The temperature, magnetic field, polarization, and doping dependencies of this mode are similar to those of the singlet bound state. The data are interpreted in terms of a spinon-assisted light scattering process. Position and form of the peak provide strong evidence for the presence of dopant-bound spinons in Cu_(1-x)Zn_xGeO_3.Comment: 4 pages, Latex with 3 figures, including EPL style files, Eur. Phys. Lett. in pres

Efficiency of antenatal care and childbirth services in selected primary health care facilities in rural Tanzania : a cross-sectional study

Background: Cost studies are paramount for demonstrating how resources have been spent and identifying opportunities for more efficient use of resources. The main objective of this study was to assess the actual dimension and distribution of the costs of providing antenatal care (ANC) and childbirth services in selected rural primary health care facilities in Tanzania. In addition, the study analyzed determining factors of service provision efficiency in order to inform health policy and planning. Methods: This was a retrospective quantitative cross-sectional study conducted in 11 health centers and dispensaries in Lindi and Mtwara rural districts. Cost analysis was carried out using step down cost accounting technique. Unit costs reflected efficiency of service provision. Multivariate regression analysis on the drivers of observed relative efficiency in service provision between the study facilities was conducted. Reported personnel workload was also described. Results: The health facilities spent on average 7 USD per capita in 2009. As expected, fewer resources were spent for service provision at dispensaries than at health centers. Personnel costs contributed a high approximate 44% to total costs. ANC and childbirth consumed approximately 11% and 12% of total costs; and 8% and 10% of reported service provision time respectively. On average, unit costs were rather high, 16 USD per ANC visit and 79.4 USD per childbirth. The unit costs showed variation in relative efficiency in providing the services between the health facilities. The results showed that efficiency in ANC depended on the number of staff, structural quality of care, process quality of care and perceived quality of care. Population-staff ratio and structural quality of basic emergency obstetric care services highly influenced childbirth efficiency. Conclusions: Differences in the efficiency of service provision present an opportunity for efficiency improvement. Taking into consideration client heterogeneity, quality improvements are possible and necessary. This will stimulate utilization of ANC and childbirth services in resource-constrained health facilities. Efficiency analyses through simple techniques such as measurement of unit costs should be made standard in health care provision, health managers can then use the performance results to gauge progress and reward efficiency through performance based incentives

Thirty Meter Telescope Site Testing I: Overview

As part of the conceptual and preliminary design processes of the Thirty Meter Telescope (TMT), the TMT site testing team has spent the last five years measuring the atmospheric properties of five candidate mountains in North and South America with an unprecedented array of instrumentation. The site testing period was preceded by several years of analyses selecting the five candidates, Cerros Tolar, Armazones and Tolonchar in northern Chile; San Pedro Martir in Baja California, Mexico and the 13 North (13N) site on Mauna Kea, Hawaii. Site testing was concluded by the selection of two remaining sites for further consideration, Armazones and Mauna Kea 13N. It showed that all five candidates are excellent sites for an extremely large astronomical observatory and that none of the sites stands out as the obvious and only logical choice based on its combined properties. This is the first article in a series discussing the TMT site testing project.Comment: Accepted for publication in PASP, April 2009 issu

Parkin-independent mitophagy controls chemotherapeutic response in cancer cells

Mitophagy is an evolutionarily conserved process that selectively targets impaired mitochondria for degradation. Defects in mitophagy are often associated with diverse pathologies, including cancer. Because the main known regulators of mitophagy are frequently inactivated in cancer cells, the mechanisms that regulate mitophagy in cancer cells are not fully understood. Here, we identified an E3 ubiquitin ligase (ARIH1/HHARI) that triggers mitophagy in cancer cells in a PINK1-dependent manner. We found that ARIH1/HHARI polyubiquitinates damaged mitochondria, leading to their removal via autophagy. Importantly, ARIH1 is widely expressed in cancer cells, notably in breast and lung adenocarcinomas; ARIH1 expression protects against chemotherapy-induced death. These data challenge the view that the main regulators of mitophagy are tumor suppressors, arguing instead that ARIH1-mediated mitophagy promotes therapeutic resistance

An impact assessment methodology for small scale renewable energy projects in developing countries funded under Dutch policies defined to contribute to the millennium development goals

Vulnerable groups, such as poor people in developing countries, are often hit hard by the effects of climate change since they lack the resources needed to cope or adapt to the changing environment. To conduct poverty reduction without compromising on the environment, the Dutch government defined a variety of policy measures. One is the so‐called Daey Ouwens Fund, established to implement small scale renewable energy projects in the poorest countries of the world. This Fund aims to contribute to Millennium Developing Goal 1, eradication of extreme poverty, and MDG 7, ensuring environmental sustainability. This paper describes the methodology developed to get a better understanding of the socioeconomic and environmental impact of projects to be implemented under the Daey Ouwens Fund. This methodology uses the multi level “Strategic Niche Management (SNM)” framework to systematically assess drivers and barriers crucial in process of innovation. For three selected projects, indicators are defined within this SNM framework, based on the MGD 1 and MGD 7 and the local socio‐economic situation as well as the existing energy system and the innovative renewable energy technology of the project. These indicators are translated into sets of questions to be quantified through a limited number of semi‐structured interviews with key persons and questionnaire inquiries of a large number of potential end‐users. The data of the conducted baseline study will be presented in this paper to provide an overall picture of the current socio‐economic situation and the energy consumption in the areas were the three selected project are going to be implemented. Based on these data and the SNM framework, an overview will be provided of drivers and barriers for the projects and the expected contribution to MDG 1 and 7. The methodology will be assessed and adapted for the impact monitoring assessment that will be held in 2013