Identification of a high-velocity compact nebular filament 2.2 arcsec south of the Galactic Centre

The central parsec of the Milky Way is a very special region of our Galaxy; it contains the supermassive black hole associated with Sgr A* as well as a significant number of early-type stars and a complex structure of streamers of neutral and ionized gas, within two parsecs from the centre, representing a unique laboratory. We report the identification of a high velocity compact nebular filament 2.2 arcsec south of Sgr A*. The structure extends over ~1 arcsec and presents a strong velocity gradient of ~200 km s^{-1} arcsec^{-1}. The peak of maximum emission, seen in [Fe III] and He I lines, is located at d{\alpha} = +0.20 +/- 0.06 arcsec and d{\delta} = -2.20 +/- 0.06 arcsec with respect to Sgr A*. This position is near the star IRS 33N. The velocity at the emission peak is Vr = -267 km s^{-1}. The filament has a position angle of PA = 115{\degr} +/- 10{\degr}, similar to that of the Bar and of the Eastern Arm at that position. The peak position is located 0.7 arcsec north of the binary X-ray and radio transient CXOGX J174540.0-290031, a low-mass X-ray binary with an orbital period of 7.9 hr. The [Fe III] line emission is strong in the filament and its vicinity. These lines are probably produced by shock heating but we cannot exclude some X-ray photoionization from the low-mass X-ray binary. Although we cannot rule out the idea of a compact nebular jet, we interpret this filament as a possible shock between the Northern and the Eastern Arm or between the Northern Arm and the mini-spiral "Bar".Comment: 7 pages, 4 figures, published online in MNRA

Housing tenure and housing demand in Colombia.

Using the 2003 and 2008 Quality of Life Surveys, we identify the factors that affect housing tenure decisions in Colombia and explore the determinants of the demand for rentals and purchases. Variables affecting the choice between buying and renting include civil status, education, age of the household head, size of the household and whether the household resides in an urban area. Households with higher income are more likely to purchase than to rent and the choice of formal housing is positively associated to wealth. Interestingly, households eligible for social housing subsidies are more likely to purchase than to rent and those working in the informal sector are more likely to purchase informal dwellings. Demand is quite responsive to price changes as well as to changes in the price of rental (its closest substitute). The elasticity to permanent income for both buying and renting is similar to that observed in other developing countries, and is higher for those working in the informal sector. This suggests that subsidies and other interventions aimed at fostering demand should not exclude those holding informal sector jobs. Demand is highly responsive to positive shocks to income, a fact probably associated with credit constraints being binding. Subsidies have a large positive impact on demand. Likewise, access to mortgage credit is an important determinant of demand. Finally, savings have a positive effect on demand in 2008, not in 2003. A plausible explanation is that a policy intervention that began in 2000 -i.e, a tax exemption for households that established savings accounts destined for housing purchases-only had an effect in the upper part of the business cycle. In both cases (i.e. subsidies and credit) the positive effect on demand is entirely explained by demand for social housing. "This paper is part of a cross-country project sponsored by the IADBs Research Network".Housing demand, tenure choices, housing market policies, Colombia.

Housing tenure and housing demand in Colombia

Using the 2003 and 2008 Quality of Life Surveys, we identify the factors that affect housing tenure decisions in Colombia and explore the determinants of the demand for rentals and purchases. Variables affecting the choice between buying and renting include civil status, education, age of the household head, size of the household and whether the household resides in an urban area. Households with higher income are more likely to purchase than to rent and the choice of formal housing is positively associated to wealth. Interestingly, households eligible for social housing subsidies are more likely to purchase than to rent and those working in the informal sector are more likely to purchase informal dwellings. Demand is quite responsive to price changes as well as to changes in the price of rental (its closest substitute). The elasticity to permanent income for both buying and renting is similar to that observed in other developing countries, and is higher for those working in the informal sector. This suggests that subsidies and other interventions aimed at fostering demand should not exclude those holding informal sector jobs. Demand is highly responsive to positive shocks to income, a fact probably associated with credit constraints being binding. Subsidies have a large positive impact on demand. Likewise, access to mortgage credit is an important determinant of demand. Finally, savings have a positive effect on demand in 2008, not in 2003. A plausible explanation is that a policy intervention that began in 2000 –i.e, a tax exemption for households that established savings accounts destined for housing purchases— only had an effect in the upper part of the business cycle. In both cases (i.e. subsidies and credit) the positive effect on demand is entirely explained by demand for social housing.

Interaction of infalling solid bodies with primordial atmospheres of disk-embedded planets

Planets that form early enough to be embedded in the circumstellar gas disk accumulate thick atmospheres of nebular gas. Models of these atmospheres need to specify the surface luminosity (i.e. energy loss rate) of the planet. This luminosity is usually associated with a continuous inflow of solid bodies, where the gravitational energy released from these bodies is the source of energy. However, if these bodies release energy in the atmosphere instead of at the surface, this assumption might not be justified. Our aim is to explore the interactions of infalling planetesimals with primordial atmospheres at an embedded phase of evolution. We investigate effects of atmospheric interaction on the planetesimals (mass loss) and the atmosphere (heating/cooling). We used atmospheric parameters from a snapshot of time-dependent evolution simulations for embedded atmospheres and simulated purely radial, infall events of siliceous planetesimals in a 1D, explicit code. We implemented energy transfer between friction, radiation transfer by the atmosphere and the body and thermal ablation; this gives us the possibility to examine the effects on the planetesimals and the atmosphere. We find that a significant amount of gravitational energy is indeed dissipated into the atmosphere, especially for larger planetary cores, which consequently cannot contribute to the atmospheric planetary luminosity. Furthermore, we examine that planetesimal infall events for cores, $M_\mathrm{C} > 2$M$_{\oplus}$, which actually result in a local cooling of the atmosphere; this is totally in contradiction with the classical model

External control strategies for self-propelled particles: optimizing navigational efficiency in the presence of limited resources

We experimentally and numerically study the dependence of different navigation strategies regarding the effectivity of an active particle to reach a predefined target area. As the only control parameter, we vary the particle's propulsion velocity depending on its position and orientation relative to the target site. By introducing different figures of merit, e.g. the time to target or the total consumed propulsion energy, we are able to quantify and compare the efficiency of different strategies. Our results suggest, that each strategy to navigate towards a target, has its strengths and weaknesses and none of them outperforms the other in all regards. Accordingly, the choice of an ideal navigation strategy will strongly depend on the specific conditions and the figure of merit which should be optimized

Bio Weide-Beef Präsentation

Die Präsentation umfasst 77 Seiten zu allen Aspekten der Produktion, von der Zucht über die Remontenproduktion und den Stallbau bis hin zur Parasitenkontrolle und Vermarktung. Die Produktion von Rindfleisch gemäss den Anforderungen von Bio Weide-Beef ist in der Schweiz ein Betriebszweig mit grossem Wachstumspotenzial

Nonlinear predictive control for durability enhancement and efficiency improvement in a fuel cell power system

© . This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/In this work, a nonlinear model predictive control (NMPC) strategy is proposed to improve the efficiency and enhance the durability of a proton exchange membrane fuel cell (PEMFC) power system. The PEMFC controller is based on a distributed parameters model that describes the nonlinear dynamics of the system, considering spatial variations along the gas channels. Parasitic power from different system auxiliaries is considered, including the main parasitic losses which are those of the compressor. A nonlinear observer is implemented, based on the discretised model of the PEMFC, to estimate the internal states. This information is included in the cost function of the controller to enhance the durability of the system by means of avoiding local starvation and inappropriate water vapour concentrations. Simulation results are presented to show the performance of the proposed controller over a given case study in an automotive application (New European Driving Cycle). With the aim of representing the most relevant phenomena that affects the PEMFC voltage, the simulation model includes a two-phase water model and the effects of liquid water on the catalyst active area. The control model is a simplified version that does not consider two-phase water dynamics.Peer ReviewedPostprint (author's final draft

We need to teach human rights in medical schools

There are protocols of the questioning of a young military physician in the Israeli Defense Forces, who performed a vaginal examination on a Palestinian woman under arrest, against the latter’s expressed will and without a medical indication. In support of the WMA guidelines on including human rights courses in medical schools, we call on medical schools to integrate a human rights perspective and introduce sufficient material on human rights, prisoners’ rights and medical ethics to help physicians like her make the right decisions in challenging situations such as the one described