52 research outputs found

    Effects of cold winters and roost site stability on population development of non-native Asian ring-necked parakeets (Alexandrinus manillensis) in temperate Central Europe – Results of a 16-year census

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    Asian ring-necked parakeets (Alexandrinus manillensis, formerly Psittacula krameri, hereafter RNP) first bred in Germany in 1969. Since then, RNP numbers increased in all three major German subpopulations (Rhineland, Rhine-Main, Rhine-Neckar) over the period 2003–2018. In the Rhine-Neckar region, the population increased to more than fivefold within only 15 years. Interestingly, there was no significant breeding range expansion of  RNP in the period 2010–2018. In 2018, the total number of RNP in Germany amounted to >16,200 birds. Differences in RNP censuses between years were evident. Surprisingly, cold winters (extreme value, −13.7 °C) and cold weather conditions in the breeding season (coldest month average, −1.36 °C) were not able to explain between-year variation. This finding suggests that in general winter mortality is low – with exceptions for winters 2008/2009 and 2009/2010, and a population-relevant loss of broods is low in our study population. Surprisingly, the social behaviour in terms of spatio-temporal stability of roost sites could well explain positive and negative population trends. Years of spatially stable and regularly used roost sites seem to correlate with increasing population sizes. In contrast, known shifts of RNP among different roost sites or the formations of new roost sites by split are related to population stagnation or a decrease in numbers. Climate change may lead to further range expansion as cities not suitable yet for RNP may become so in the near future.

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    From Duty to Right: The Role of Public Education in the Transition to Aging Societies

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    This paper argues that the introduction of compulsory schooling in early industrialization promoted the growth process that eventually led to a vicious cycle of population aging and negative pressure on education policy. In the early phases of industrialization, public education was undesirable for the young poor who relied on child labor. Compulsory schooling therefore discouraged childbirth, while the accompanying industrialization stimulated their demand for education. The subsequent rise in the share of the old population, however, limited government resources for education, placing heavier financial burdens on the young. This induced further fertility decline and population aging, and the resulting cycle may have delayed the growth of advanced economies in the last few decades

    Aid on Demand: African Leaders and the Geography of China's Foreign Assistance

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    Measurement of jet fragmentation in Pb+Pb and pppp collisions at sNN=2.76\sqrt{{s_\mathrm{NN}}} = 2.76 TeV with the ATLAS detector at the LHC

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    Teaching medicine web-based with the help of interactive audience response systems

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    The COVID-19 pandemic confronted the medical community worldwide with numerous challenges, not only with respect to medical care, but also for teaching the next generation of physicians. To minimize the risk of infections patient-unrelated classes can be held digitally. Here we present a student initiated, web-based teaching approach, called “From symptom to diagnosis”. In this seminar case reports of rare diseases were presented to the audience in a symptom-focused manner. The patients´ most significant symptoms were presented, followed by an in-depth discussion about differential diagnosis. First glance diagnosis pictures were shown to improve students´ ability to identify important clinical scenarios. We used chat functions as well as an audience response system to make the seminar more interactive. By this we attracted between 71 and 147 participants per session. The online seminar was very well perceived and 97% of the students saw an improvement of their diagnostic skills. In summary, we successfully established an interactive, web-based teaching format for medical students

    A Hardware Architecture for Dynamic Performance and Energy Adaptation

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    Energy consumption of any component in a system may sometimes constitute just a small percentage of that of the overall system, making it necessary to address the issue of energy efficiency across the entire range of system components, from memory, to the CPU, to peripherals. Presented is a hardware architecture for detecting regions of application execution at runtime, for which there is opportunity to run a device at a slightly lower performance level, by reducing the operating frequency and voltage, to save energy. The proposed architecture, the Power Adaptation Unit (PAU) may be used to control the operating voltage of various system components, ranging from the CPU core, to memory and peripherals

    On-orbit servicing

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    You have a flat tire. You will have to buy a new car!" While on earth, nobody would follow such advice; in space, there are few other options than to replace a malfunctioning spacecraft. There are no repair shops and gas stations in the earth orbit. Because of the lack of so-called on-orbit servicing (OOS) opportunities, some malfunctioning spacecraft continue operational work with reduced or hardly any performance. The only general modification, which can currently be undertaken to an arbitrary spacecraft in orbit, is a software update. For example, the bispectral infrared detection (BIRD) satellite [1] started in 2001 with a configuration of four high-precision reaction wheels. Losing one after the other and with only one functional remaining, a significant effort has been made to optimize the attitude-control software with regards to the new constraints. Thus, BIRD is still operational, but other hardware failures, e.g., the inability to deploy solar panels, cannot be compensated by modifying the onboard software. In case of TV-SAT 1 [2], solar panel problems (the fastening bolt for the solar array had accidentally not been removed before launch) prevented the use of the Ku-band transmit antenna and subsequently any TV broadcast service after launch. The satellite had to be moved into a graveyard orbit
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