Highest weight irreducible representations of the Lie superalgebra gl(1/∞)gl(1/\infty)

Two classes of irreducible highest weight modules of the general linear Lie superalgebra $gl(1/\infty)$ are constructed. Within each module a basis is introduced and the transformation relations of the basis under the action of the algebra generators are written down.Comment: 24 pages, TeX; Journ. Math. Phys. (to be published

Computation and interpretation of insolation tables

IBM 7074 computer program for computation of insolation tables for surface of Mar

The influence of the synoptic regime on stable water isotopes in precipitation at Dome C, East Antarctica

Abstract. The correct derivation of paleotemperatures from ice cores requires exact knowledge of all processes involved before and after the deposition of snow and the subsequent formation of ice. At the Antarctic deep ice core drilling site Dome C, a unique data set of daily precipitation amount, type, and stable water isotope ratios is available that enables us to study in detail atmospheric processes that influence the stable water isotope ratio of precipitation. Meteorological data from both automatic weather station and a mesoscale atmospheric model were used to investigate how different atmospheric flow patterns determine the precipitation parameters. A classification of synoptic situations that cause precipitation at Dome C was established and, together with back-trajectory calculations, was utilized to estimate moisture source areas. With the resulting source area conditions (wind speed, sea surface temperature, and relative humidity) as input, the precipitation stable isotopic composition was modeled using the so-called Mixed Cloud Isotope Model (MCIM). The model generally underestimates the depletion of 18O in precipitation, which was not improved by using condensation temperature rather than inversion temperature. Contrary to the assumption widely used in ice core studies, a more northern moisture source does not necessarily mean stronger isotopic fractionation. This is due to the fact that snowfall events at Dome C are often associated with warm air advection due to amplification of planetary waves, which considerably increases the site temperature and thus reduces the temperature difference between source area and deposition site. In addition, no correlation was found between relative humidity at the moisture source and the deuterium excess in precipitation. The significant difference in the isotopic signal of hoarfrost and diamond dust was shown to disappear after removal of seasonality. This study confirms the results of an earlier study carried out at Dome Fuji with a shorter data set using the same methods

Topological properties of quantum periodic Hamiltonians

We consider periodic quantum Hamiltonians on the torus phase space (Harper-like Hamiltonians). We calculate the topological Chern index which characterizes each spectral band in the generic case. This calculation is made by a semi-classical approach with use of quasi-modes. As a result, the Chern index is equal to the homotopy of the path of these quasi-modes on phase space as the Floquet parameter (\theta) of the band is varied. It is quite interesting that the Chern indices, defined as topological quantum numbers, can be expressed from simple properties of the classical trajectories.Comment: 27 pages, 14 figure

COMMUNITY AND NETWORK RESPONSES FOR ASSISTING MOBILE VULNERABLE POPULATIONS

The COVID-19 crisis highlighted the increasing vulnerability of individuals, households, and communities. It has almost certainly been even more devastating for those who rely on community networks and organizations for aid but are less able to access aid networks in conditions of reduced mobility. This is the case for “mobile vulnerable populations,” among which include persons experiencing homelessness, victims of human trafficking,immigrants, refugees, and Latinos/as. This report summarizes our research with local Omaha service providers about what they need to serve mobile vulnerable populations in the community, how the pandemic has affected their ability to do so, and whether there have been any substantial and/or institutionalized partnerships between UNO/UNMC and these community organizations. In our research, we used a multi-method approach consisting of a survey of community organization leaders and interviews with organization workers engaged into day-to-day service provision to meet the needs of their clients. Our findingscan be summarized in four main themes: (a) organizations were already under-resourced prior to the pandemic; (b) the impact of the COVID-19 pandemic on organizations was substantial; (c) organizations described similar strengths and innovative responses to the pandemic; and (d) there is a lack of institutionalized collaboration with UNO/UNMC. We argue that building connections between UNO/UNMC and community organizations, as well as assisting in the development of networks among various organizations, is central to the mission of the University of Nebraska system and could benefitthe community more broadly. Concluding, we present four main recommendations: (1) more connections are needed between UNO/UNMC and agencies in the Omaha area; (2) it is likely that there are existing relationships between agency partners and UNO/UNMC faculty, staff and students that could be leveraged; (3) there is an opportunity to prepare students and emphasize workforce growth among providers; and (4) the important work of serving mobile vulnerable populations can be rewarding but also challenging for Omaha providers

Coping With COVID-19: Mindfulness-Based Approaches for Mitigating Mental Health Crisis

The novel coronavirus disease COVID-19 that first emerged in Wuhan, China, in Nov-Dec 2019 has already impacted a significant proportion of the world population. Governments of many countries imposed quarantines and social distancing measures in 2020, many of which remain in place, to mitigate the spread of the SARS-Cov-2 virus causing the COVID-19 disease. The direct impact of COVID-19 on people infected with the virus, their families and the health care workers, as well as the impact of the mitigation measures such as quarantine, social distancing, and self-isolation on the rest of the population have contributed to a global mental health pandemic, including anxiety, depression, panic attacks, posttraumatic stress symptoms, psychosis, addiction, obsessive-compulsive disorder, and suicidality. These effects are present acutely (for example, due to fear of contamination or losing loved ones, effects of quarantine/isolation, withdrawal of community and social services, etc.) and may continue long after the pandemic is over (for example, due to bereavement, unemployment, financial losses, etc). The COVID-19 pandemic has triggered mental health problems in people without previous history of mental illness, as well as worsened the symptoms in those with pre-existing psychiatric diagnosis. Therefore, the global effort is called for to deal with this mental health pandemic secondary to COVID-19 itself to address the emergence of new as well as the exacerbation of the existing mental health issues. Conversely, this global context provides an extraordinary opportunity for studying individual differences in response to and resilience in the face of physical and psychological threat, challenge to “normal” way of life, and long-term uncertainty. In this viewpoint article we outline the particular suitability of mindfulness, its skills and mechanisms, as an approach to the prevention and management of mental health issues, as well as to the promotion of well-being and building the foundations of adaptability and flexibility in dealing with the long-term uncertainty and profound changes to the social, economic, and possibly political systems as this pandemic continues to unfold.BIAL Foundation grant

Aminoacyl-tRNA-Charged Eukaryotic Elongation Factor 1A Is the Bona Fide Substrate for Legionella pneumophila Effector Glucosyltransferases

Legionella pneumophila, which is the causative organism of Legionnaireś disease, translocates numerous effector proteins into the host cell cytosol by a type IV secretion system during infection. Among the most potent effector proteins of Legionella are glucosyltransferases (lgt's), which selectively modify eukaryotic elongation factor (eEF) 1A at Ser-53 in the GTP binding domain. Glucosylation results in inhibition of protein synthesis. Here we show that in vitro glucosylation of yeast and mouse eEF1A by Lgt3 in the presence of the factors Phe-tRNAPhe and GTP was enhanced 150 and 590-fold, respectively. The glucosylation of eEF1A catalyzed by Lgt1 and 2 was increased about 70-fold. By comparison of uncharged tRNA with two distinct aminoacyl-tRNAs (His-tRNAHis and Phe-tRNAPhe) we could show that aminoacylation is crucial for Lgt-catalyzed glucosylation. Aminoacyl-tRNA had no effect on the enzymatic properties of lgt's and did not enhance the glucosylation rate of eEF1A truncation mutants, consisting of the GTPase domain only or of a 5 kDa peptide covering Ser-53 of eEF1A. Furthermore, binding of aminoacyl-tRNA to eEF1A was not altered by glucosylation. Taken together, our data suggest that the ternary complex, consisting of eEF1A, aminoacyl-tRNA and GTP, is the bona fide substrate for lgt's

Investigation of defect formation and electronic transport in microcrystalline silicon deposited by hot-wire CVD

We have investigated doped and undoped layers of microcrystalline silicon prepared by hot-wire chemical vapour deposition optically, electrically and by means of transmission electron microscopy. Besides needle-like crystals grown perpendicular to the substrate's surface, all of the layers contained a noncrystalline phase with a volume fraction between 4% and 25%. A high oxygen content of several per cent in the porous phase was detected by electron energy loss spectrometry. Deep-level transient spectroscopy of the crystals suggests that the concentration of electrically active defects is less than 1% of the undoped background concentration of typically 10^17 cm -3. Frequency-dependent measurements of the conductance and capacitance perpendicular to the substrate surface showed that a hopping process takes place within the noncrystalline phase parallel to the conduction in the crystals. The parasitic contribution to the electrical circuit arising from the porous phase is believed to be an important loss mechanism in the output of a pin-structured photovoltaic solar cell deposited by hot-wire CVD