Linking the Quark Meson Model with QCD at High Temperature

We model the transition of a system of quarks and gluons at high energies to a system of quarks and mesons at low energies in a consistent renormalization group approach. Flow equations interpolate between the physics of the high-temperature degrees of freedom and the low-temperature dynamics at a scale of 1 GeV. We also discuss the dependence of the equation of state on baryon density and compare our results with recent lattice gauge simulations.Comment: 11 pages, 4 figures additional discussion of the second order phase transitio

Neutrino Emission from Ungapped Quark Matter

We study neutrino emission from a normal, ungapped, quark phase in the core of a compact star. Neutrino emission from non-interacting quark matter leads to an emissivity that scales as $\epsilon\sim T^7$. We show that the emissivity is enhanced by a combination of Fermi liquid and non-Fermi liquid effects. Fermi liquid effects lead to an emissivity that scales as $\epsilon\sim \alpha_s T^6$, as originally shown by Iwamoto. We demonstrate that non-Fermi liquid effects further enhance the rate, leading to $\epsilon\sim \alpha_s^3 T^6\log(m/T)^2$, where $m$ is the electric screening scale and $m\gg T$ under the conditions found in compact stars. We show, however, that combined with non-Fermi liquid effects in the specific heat the enhancement in the emissivity only leads to a modest reduction in the temperature of the star at late times. Our results confirm existing bounds on the presence of ungapped quark matter in compact stars. We also discuss neutrino emission from superconducting phases with ungapped fermionic excitations.Comment: minor corrections, published versio

Trace element mobility in cold desert alteration systems

Introduction: Alteration of rocks is a fundamental process that occurs in all environments across the solar system in different forms. Understanding the patterns of alteration, the formation of different products, the liberation of certain elements from minerals can inform us about environments billions of years old. They can give us information about quantities of water, temperatures, atmospheres and biology. This study focuses on cold desert environments and the geochemical fingerprints processes leave in some of the most abundant minerals in the solar system. Specifically, this study looks at how trace elements move in cold weathering systems, using Antarctic ordinary chondrites as an analogue, and how weathering features of cold environments combine with little water to interact with rocks.</br

Labelmars.det: Crowd-sourcing an extremely large high quality Martian image dataset.

The observation of landforms, outcrops and small features within a (Martian) landscape is key to the understanding of its geologic past as well as present environmental conditions. Studies of such features have – for example – revealed the nature of streambeds at Gale Crater, and allowed to study Aeolian bedforms as they were encountered by the Curiosity, and Spirit rovers. With two active rovers (Opportunity, Curiosity) currently on Mars, and two more to be launched in 2020 (ExoMars, Mars2020), the imaging data sets are a huge, growing resource, which need to be explored as best as possible. LabelMars (www.labelmars.net) is a citizen science activity to collect geological annotations of Martian rover navigation camera images. As part of the ESA NOAH (Novelty Or Anomaly Hunter) project it will provide a large, high quality dataset to develop stateof-the-art machine vision algorithms for autonomous science detection, targeted at future rover missions

Cold desert weathering effects on magnetic properties of L6 chondrites

Antarctic weathering of ordinary chondrites primarily affects Fe-Ni metals which are the main magnetic minerals of the meteorites. The magnetic properties of meteorites can thus be used as proxies to weathering state. The alteration products resulting from oxidation and weathering of the metals can also have magnetic properties of their own. However, the mode of weathering that operates in different environments varies, as do the products. As such, understanding how the magnetic properties are affected in Antarctica is important to recognize and understand

Large sulfur isotope fractionations in Martian sediments at Gale crater

Variability in the sulfur isotopic composition in sediments can reflect atmospheric, geologic and biological processes. Evidence for ancient fluvio-lacustrine environments at Gale crater on Mars and a lack of efficient crustal recycling mechanisms on the planet suggests a surface environment that was once warm enough to allow the presence of liquid water, at least for discrete periods of time, and implies a greenhouse effect that may have been influenced by sulfur-bearing volcanic gases. Here we report in situ analyses of the sulfur isotopic compositions of SO2 volatilized from ten sediment samples acquired by NASA’s Curiosity rover along a 13 km traverse of Gale crater. We find large variations in sulfur isotopic composition that exceed those measured for Martian meteorites and show both depletion and enrichment in 34S. Measured values of δ34S range from −47 ± 14‰ to 28 ± 7‰, similar to the range typical of terrestrial environments. Although limited geochronological constraints on the stratigraphy traversed by Curiosity are available, we propose that the observed sulfur isotopic signatures at Gale crater can be explained by equilibrium fractionation between sulfate and sulfide in an impact-driven hydrothermal system and atmospheric processing of sulfur-bearing gases during transient warm periods

Comparative Interpretation Standards in Uniform International Law

In this chapter, the author offers a horizontal comparison of interpretation standards contained in international legal instruments of different origin. These legal instruments range from international treaties to model laws. They also originate from different law makers such as the United Nations or individual states as well as trade or academic organisations, mainly regulating civil and commercial matters. The author argues that this comparison can provide the basis for the development of a uniform standard in the application of such law, which is often referred to as uniform law because it provides a single source of law to regulate a multitude of situations spanning across national boundaries. The main point of reference is the 1969 Vienna Convention on the Law of Treaties, also known as the VCLT. This UN treaty specifically provides a general interpretation standard. From there newer standards occurring in subsequent uniform laws can be integrated using the lex specialis doctrine. This, in turn, provides opportunities for comprehensive usable methods to be developed for uniform law both in a public and private law settings. These then facilitate transparency, fairness and reasonableness. The correct identification of object and purposes of any given instrument is crucial for the successful interpretation of its content. It is this point that needs further research, and this chapter offers a starting point by providing some detailed examples from a range of uniform laws of varying nature including international sales laws, arbitration laws and Double Taxation Conventions

Chemical vapor deposited polymer layer for efficient passivation of planar perovskite solar cells

Reducing non-radiative recombination losses by advanced passivation strategies is pivotal to maximize the power conversion efficiency (PCE) of perovskite solar cells (PSCs). Previously, polymers such as poly(methyl methacrylate), poly(ethylene oxide), and polystyrene were successfully applied in solution-processed passivation layers. However, controlling the thickness and homogeneity of these ultra-thin passivation layers on top of polycrystalline perovskite thin films is a major challenge. In response to this challenge, this work reports on chemical vapor deposition (CVD) polymerization of poly(p-xylylene) (PPX) layers at controlled substrate temperatures (14–16 °C) for efficient surface passivation of perovskite thin films. Prototype double-cation PSCs using a ∼1 nm PPX passivation layer exhibit an increase in open-circuit voltage (V$_{OC}$) of ∼40 mV along with an enhanced fill factor (FF) compared to a non-passivated PSC. These improvements result in a substantially enhanced PCE of 20.4% compared to 19.4% for the non-passivated PSC. Moreover, the power output measurements over 30 days under ambient atmosphere (relative humidity ∼40–50%) confirm that the passivated PSCs are more resilient towards humidity-induced degradation. Considering the urge to develop reliable, scalable and homogeneous deposition techniques for future large-area perovskite solar modules, this work establishes CVD polymerization as a novel approach for the passivation of perovskite thin films

Constraints on possible phase transitions above the nuclear saturation density

We compare different models for hadronic and quark phases of cold baryon-rich matter in an attempt to find a deconfinement phase transition between them. For the hadronic phase we consider Walecka-type mean-field models which describe well the nuclear saturation properties. We also use the variational chain model which takes into account correlation effects. For the quark phase we consider the MIT bag model, the Nambu-Jona-Lasinio and the massive quasiparticle models. By comparing pressure as a function of baryon chemical potential we find that crossings of hadronic and quark branches are possible only in some exceptional cases while for most realistic parameter sets these branches do not cross at all. Moreover, the chiral phase transition, often discussed within the framework of QCD motivated models, lies in the region where the quark phases are unstable with respect to the hadronic phase. We discuss possible physical consequences of these findings.Comment: 28 pages, 18 PostScript figures, submitted to Phys. Rev.