Earnings and wealth inequality and income taxation: quantifying the tradeoffs of switching to a proportional income tax in the U.S.

This paper quantifies the steady-state aggregate, distributional, and mobility effects of switching the U.S. to a proportional income tax system.Income tax

Degradation of microbial fluorescence biosignatures by solar ultraviolet radiation on Mars

Recent and proposed robotic missions to Mars are equipped with implements to expose or excavate fresh material from beneath the immediate surface. Once brought into the open, any organic molecules or potential biosignatures of present or past life will be exposed to the unfiltered solar ultraviolet (UV) radiation and face photolytic degradation over short time courses. The key question, then, is what is the window of opportunity for detection of recently exposed samples during robotic operations? Detection of autofluorescence has been proposed as a simple method for surveying or triaging samples for organic molecules. Using a Mars simulation chamber we conduct UV exposures on thin frozen layers of two model microorganisms, the radiation-resistant polyextremophile Deinococcus radiodurans and the cyanobacterium Synechocystis sp. PCC 6803. Excitation–emission matrices (EEMs) are generated of the full fluorescence response to quantify the change in signal of different cellular fluorophores over Martian equivalent time. Fluorescence of Deinococcus cells, protected by a high concentration of carotenoid pigments, was found to be relatively stable over 32 h of Martian UV irradiation, with around 90% of the initial signal remaining. By comparison, fluorescence from protein-bound tryptophan in Synechocystis is much more sensitive to UV photodegradation, declining to 50% after 64 h exposure. The signal most readily degraded byUV irradiation is fluorescence of the photosynthetic pigments – diminished to only 35% after 64 h. This sensitivity may be expected as the biological function of chlorophyll and phycocyanin is to optimize the harvesting of light energy and so they are readily photobleached. A significant increase in a *450 nm emission feature is interpreted as accumulation of fluorescent cellular degradation products from photolysis. Accounting for diurnal variation in Martian sunlight, this study calculates that frozen cellular biosignatures would remain detectable by fluorescence for at least several sols; offering a sufficient window for robotic exploration operations

Nd3+-doped TeO2–PbF2–AlF3 glasses for laser applications

A study of the optical properties of Nd3+ ion in TeO2–PbF2–AlF3 glasses has been carried out for different Nd3+ concentrations. Based on the Judd–Ofelt theory, intensity parameters and radiative properties were determined from the absorption spectra. Focusing on the suitability of this host for laser applications, the spectroscopic quality factor v was obtained with a value of 1.07, a value of the order of other compositions proposed as laser hosts. For the most intense emission corresponding with the 4F3/2?4I11/2 transition (1.06 lm), the absorption and emission and have been calculated with values of 1.20 10 20 cm2, 2.08 10 20 cm2. A positive value for the gain cross-sections has been found for a population inversion factor c of 0.4 in the spectral range from 1060 to 1110 nm. All these results suggest the potentially use of this system as a laser host

Surface and capillary transitions in an associating binary mixture model

We investigate the phase diagram of a two-component associating fluid mixture in the presence of selectively adsorbing substrates. The mixture is characterized by a bulk phase diagram which displays peculiar features such as closed loops of immiscibility. The presence of the substrates may interfere the physical mechanism involved in the appearance of these phase diagrams, leading to an enhanced tendency to phase separate below the lower critical solution point. Three different cases are considered: a planar solid surface in contact with a bulk fluid, while the other two represent two models of porous systems, namely a slit and an array on infinitely long parallel cylinders. We confirm that surface transitions, as well as capillary transitions for a large area/volume ratio, are stabilized in the one-phase region. Applicability of our results to experiments reported in the literature is discussed.Comment: 12 two-column pages, 12 figures, accepted for publication in Physical Review E; corrected versio

Orientational transitions in a nematic confined by competing surfaces

The effect of confinement on the orientational structure of a nematic liquid crystal model has been investigated by using a version of density-functional theory (DFT). We have focused on the case of a nematic confined by opposing flat surfaces, in slab geometry (slit pore), which favor planar molecular alignment (parallel to the surface) and homeotropic alignment (perpendicular to the surface), respectively. The spatial dependence of the tilt angle of the director with respect to the surface normal has been studied, as well as the tensorial order parameter describing the molecular order around the director. For a pore of given width, we find that, for weak surface fields, the alignment of the nematic director is perpendicular to the surface in a region next to the surface favoring homeotropic alignment, and parallel along the rest of the pore, with a interface separating these regions (S phase). For strong surface fields, the director is distorted uniformly, the tilt angle exhibiting a linear dependence with the distance normal to the surface (L phase). Our calculations reveal the existence of a first-order transition between the two director configurations, which is driven by changes in the surface field strength, and also by changes in the pore width. In the latter case the transition occurs, for a given surface field, between the S phase for narrow pores and the L phase for wider pores. A link between the L-S transition and the anchoring transition observed for the semi-infinite case is proposed. We also provide calculations with a phenomenological approach that yields the same main result that DFT in the scale length where this is valid.Comment: submitted to PR

Raman spectroscopic analysis of the calcium oxalate producing extremotolerant lichen Circinaria gyrosa

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.In the context of astrobiological exposure and simulation experiments in the BIOMEX project, the lichen Circinaria gyrosa was investigated by Raman microspectroscopy. Owing to the symbiotic nature of lichens and their remarkable extremotolerance, C. gyrosa represents a valid model organism in recent and current astrobiological research. Biogenic compounds of C. gyrosa were studied that may serve as biomarkers in Raman assisted remote sensing missions, e.g. ExoMars. The surface as well as different internal layers of C. gyrosa have been characterized and data on the detectability and distribution of β-carotene, chitin and calcium oxalate monohydrate (whewellite) are presented in this study. Raman microspectroscopy was applied on natural samples and thin sections. Although calcium oxalates can also be formed by rare geological processes it may serve as a suitable biomarker for astrobiological investigations. In the model organism C. gyrosa, it forms extracellular crystalline deposits embedded in the intra-medullary space and its function is assumed to balance water uptake and gas exchange during the rare, moist to wet environmental periods that are physiologically favourable. This is a factor that was repeatedly demonstrated to be essential for extremotolerant lichens and other organisms. Depending on the decomposition processes of whewellite under extraterrestrial environmental conditions, it may not only serve as a biomarker of recent life, but also of past and fossilized organisms.BMWi, 50WB1153, Analysen zur Stabilität und Degradation biogener Substanzen sowie zum Resistenzpotential der Fleche Buellia frigida unter simulierten Marsbedingungen und nach Exposition im LEO-Weltrau

Haplotype Structure of FSHB, the Beta-Subunit Gene for Fertility-Associated Follicle-Stimulating Hormone: Possible Influence of Balancing Selection

Follicle-stimulating hormone (FSH) is essential for human reproduction. The unique functions of this hormone are provided by the FSH receptor-binding beta-subunit encoded by the FSHB gene. Resequencing and genotyping of FSHB in three European, two Asian and one African population, as well as in the great apes (chimpanzee, gorilla, orangutan), revealed low diversity and significant excess of polymorphisms with intermediate frequency alleles. Statistical tests for FSHB showed deviations from neutrality in all populations suggesting a possible effect of balancing selection. Two core haplotypes were identified (carried by 76-96.6% of each population's sample), the sequences of which are clearly separated from each other. As fertility most directly affects an organism's fitness, the carriers of these haplotypes have apparently had more success in human history to contribute to the next generation. There is a preliminary observation suggesting that the second most frequent FSHB haplotype may be associated with rapid conception success in females. Interestingly, the same haplotype is related to an ancestral FSHB variant shared with the ancestor of the great apes. The determination of the functional consequence of the two core FSHB variants may have implications for understanding and regulating human fertility, as well as in assisting infertility treatments

Glycoprotein profile assessed by1h-nmr as a global inflammation marker in patients with HIV infection. A prospective study

Plasma glycoproteins are a composite biomarker of inflammation and can be detected byH-NMR. The aim of this study was to prospectively appraise the clinical value of plasma glycopro-teins assessed byH-NMR in people living with HIV (PLWH). A total of 221 patients with HIV infection were recruited and studied at baseline and at 48 and 144 weeks. Patients were distributed into two groups according to baseline CD4 T-cell number below or above 200 cells/µL. Patients with fewer than 200 cells/µL were distributed into the responders and nonresponders according to antiretroviral therapy (ART) response at 144 weeks. Glycoprotein concentrations were determined byH-NMR arising from the protein bond N-acetylglucosamine and N-acetylgalactosamine signals (GlycA); and N-acetylneuraminic acid signal (GlycB) associated with the sugar-protein bond con-centration and aggregation state (shapes (height/width)). Basal glycoprotein concentrations were higher in patients with < 200 CD4 T-cell/µL (Glyc A: 1040(917.9-1199.1) vs. 950.4(845.5-1050.9), p < 0.001, and Glyc B: 521(440.3-610.3) vs. 468.6(417.9-507.0) µ mol/L, p < 0.001) being reduced by ART. The height/width (H/W) ratio was the parameter showing a better association with this clinical sta-tus. Baseline glycoproteins predict the condition of responder/nonresponder. In this study,H-NMR glycoproteins provide novel insights to assess inflammation status and have prognostic value in PLWH

Updated site compilation of the Latin American Pollen Database

Flantua, Suzette G A et al.The updated inventory of the Latin American Pollen Database (LAPD) offers a wide range of new insights. This paper presents a systematic compilation of palynological research in Latin America. A comprehensive inventory of publications in peer-reviewed and grey literature shows a major expansion of studies over the last decades. The inventory includes 1379 cores and sections with paleoecological data and more than 4800 modern samples from throughout the continent. Through the years, pollen datasets extend over increasing spans of time and show improved taxonomic and temporal resolution. Currently, these datasets are from 12 modern biomes and 30 countries, covering an altitudinal range of 0 to 6300. m asl. The most densely sampled regions are the Colombian Andes, the southeast coast of Brazil, and Patagonia. Underrepresented biomes are the warm temperate mixed forest (3%), dry forests (3%), and warm temperate rainforest (1%); whereas steppe, tropical rainforest, and cool grass shrublands, such as the páramos, are generally well represented (all >. 17%). There are 126 records that span the late Pleistocene to the Last Glacial Maximum transition (21,000. cal. yr BP), and >. 20% of the records cover the Younger Dryas interval and the Pleistocene/Holocene transition. Reanalysis of numerous sites using multiproxy tools emphasize the informative value of this approach in paleoenvironmental reconstruction. We make suggestions for several pollen sites and regions to be visited again; similarly we identify some key research questions that have yet to be answered. The updated LAPD now provides the platform to support an exciting new phase of global palynological research in which multi-site data are being integrated to address current cutting-edge research questions. The LAPD compilation of sites and the literature database will be available through the Neotoma Paleoecology Database website and a new LAPD website by the end of 2015We thank the Netherlands Organization for Scientific Research (NWO, grant 2012/13248/ALW) for financial support of this project.Peer reviewe