Decomposition of jacobians of generalized Fermat curves

We give a decomposition of the jacobian variety of a generalized Fermat curve. This extends a result obtained by Auffarth, Lucchini-Arteche and Rojas on Humbert-Edge curves, which are a particular case of generalized Fermat curves.Comment: 12 page

Assignment markets with the same core

In the framework of bilateral assignment games, we study the set of matrices associated with assignment markets with the same core. We state conditions on matrix entries that ensure that the related assignment games have the same core. We prove that the set of matrices leading to the same core form a join-semilattice with a nite number of minimal elements and a unique maximum. We provide a characterization of the minimal elements. A sucient condition under which the join-semilattice reduces to a lattice is also given.core, semilattice, assignment game

Stated Willingness to Pay for Residential Renewable Electricity and Green Jobs in Aguascalientes, Mexico

Via a discrete choice experiment, this paper documents that residential electricity consumers in Aguascalientes, Mexico, are willing to pay a premium for renewable energies as well as for the creation of green jobs. These results are particularly timely because the current Federal administration has redirected priorities from an energy transition that was expected to boost renewable energies to the pursuing of energy sovereignty. Concerns regarding this prioritization have been raised by national and international stakeholders due to its potential economic inefficiency and its implications for the achievement of climate change goals. These concerns have only intensified as discussions begin on how Mexico should face the post-coronavirus recession. This paper’s findings open the door to discuss whether a combination of a just energy transition together with the boosting of renewable energies should be part of a strategy to reach energy sovereignty at the same time that Mexico deals with a post-coronavirus world

Variability in high-mass X-ray binaries

Strongly magnetized, accreting neutron stars show periodic and aperiodic variability over a wide range of time scales. By obtaining spectral and timing information on these different time scales, we can have a closer look into the physics of accretion close to the neutron star and the properties of the accreted material. One of the most prominent time scales is the strong pulsation, i.e., the rotation period of the neutron star itself. Over one rotation, our view of the accretion column and the X-ray producing region changes significantly. This allows us to sample different physical conditions within the column but at the same time requires that we have viewing-angle-resolved models to properly describe them. In wind-fed high-mass X-ray binaries, the main source of aperiodic variability is the clumpy stellar wind, which leads to changes in the accretion rate (i.e., luminosity) as well as absorption column. This variability allows us to study the behavior of the accretion column as a function of luminosity, as well as to investigate the structure and physical properties of the wind, which we can compare to winds in isolated stars.Comment: 6 pages, 4 figures, accepted for publication in Astronomische Nachrichten (proceedings of the XMM-Newton Workshop 2019

Submitral left ventricular aneurysm associated with thrombus

Background: Submitral left ventricular aneurysm is a rarely reported cardiac abnormality that is encountered commonly among blacks. So far, only one case has been reported from Ethiopia and East Africa.Our aim is to report an interesting and rare case that we encountered at St. Paul’s Hospital Millennium Medical College.Methods: In April 2017, a 25-year-old patient havingsubmitral left ventricular aneurysm with New York Heart Association (NYHA) class IV heart failure and mild left ventricular systolic dysfunctionreceived medical treatment at our institution. She had severe mitral regurgitation and aneurysmal thrombus. The diagnosis was easily made using GE Vivid E9 transthoracic echocardiography. She was given drugs for management of heart failure and anticoagulation.Results: Our patient was discharged with a stable condition, and she had no early mortality. At 3 months’ follow-up,shehad clinical improvement with NYHA class II heart failure, slight improvement of left ventricular systolic function, and resolution of the left ventricular thrombus. However, there waspersistent severe mitral regurgitation and aneurysm.Conclusion: Submitral left ventricular aneurysm is a rare cardiac abnormality. Diagnosis can be easily made with echocardiography. Surgery is the definitive treatment. However, it is not currently available in the country and patients cannot afford treatment abroad.Keywords: Ethiopia, heart failure, submitral aneurysm, thrombu

Gas-phase formation of glycolonitrile in the interstellar medium

Our automated reaction discovery program, AutoMeKin, has been utilized to investigate the formation of glycolonitrile (HOCH$_{2}$CN) in the gas phase under the low temperatures of the interstellar medium (ISM). The feasibility of a proposed pathway depends on the absence of barriers above the energy of reactants and the availability of the suggested precursors in the ISM. Based on these criteria, several radical-radical reactions and a radical-molecule reaction have been identified as viable formation routes in the ISM. Among the radical-radical reactions, OH+CH$_{2}$CN appears to be the most relevant, considering the energy of the radicals and its ability to produce glycolonitrile in a single step. However, our analysis reveals that this reaction produces hydrogen isocyanide (HNC) and formaldehyde (CH$_{2}$O), with rate coefficients ranging from (7.3-11.5)$\times$10$^{-10}$ cm$^3$ molecule$^{-1}$ s$^{-1}$ across the temperature range of 10-150 K. This finding is particularly interesing given the persistently unexplained overabundance of hydrogen isocyanide in the ISM. Among the radical-molecule reactions investigated, the most promising one is OH+CH$_{2}$CNH, which forms glycolonitrile and atomic hydrogen with rate coefficients in the range (0.3-6.6)$\times$10$^{-10}$ cm$^3$ molecule$^{-1}$ s$^{-1}$ within the 10-150 K temperature range. Our calculations indicate that the formation of both hydrogen isocyanide and glycolonitrile is efficient under the harsh conditions of the ISM

Changes in growth of tropical forests: evaluating potential biases

Over the past century almost every ecosystem on Earth has come under the influence of changes in atmospheric composition and climate caused by human activity. Tropical forests are among the most productive and extensive ecosystems, and it has been hypothesized that both the dynamics and biomass of apparently undisturbed, old-growth tropical forests have been changing in response to atmospheric changes. Long-term forest sample plots are a critical tool in detecting and monitoring such changes, and our recent analysis of pan-tropical-forest plot data has suggested that the biomass of tropical forests has been increasing, providing a modest negative feedback on the rate of accumulation of atmospheric CO2. However, it has been argued that some of these old forest plot data sets have significant problems in interpretation because of the use of nonstandardized methodologies. In this paper we examine the extent to which potential field methodological errors may bias estimates of total biomass change by detailed examination of tree-by-tree records from up to 120 Neotropical plots to test predictions from theory. Potential positive biases on measurements of biomass change include a bias in site selection, tree deformities introduced by the measurement process, poor methodologies to deal with tree deformities or buttresses, and nonrecording of negative growth increments. We show that, while it is important to improve and standardize methodologies in current and future forest-plot work, any systematic errors introduced by currently identified biases in past studies are small and calculable. We conclude that most tropical-forest plot data are of useful quality, and that the evidence does still weigh conclusively in favor of a recent increase of biomass in old-growth tropical forests

INTEGRAL-RXTE observations of Cygnus X-1

We present first results from contemporaneous observations of Cygnus X-1 with INTEGRAL and RXTE, made during INTEGRAL's performance verification phase in 2002 November and December. Consistent with earlier results, the 3-250 keV data are well described by Comptonization spectra from a Compton corona with a temperature of kT~50-90 keV and an optical depth of tau~1.0-1.3 plus reflection from a cold or mildly ionized slab with a covering factor of Omega/2pi~0.2-0.3. A soft excess below 10 keV, interpreted as emission from the accretion disk, is seen to decrease during the 1.5 months spanned by our observations. Our results indicate a remarkable consistency among the independently calibrated detectors, with the remaining issues being mainly related to the flux calibration of INTEGRAL.Comment: 6 pages, 3 figures. Figs. 2 and 3 are best viewed in color. Accepted for publication in the INTEGRAL special edition of A&A