Pattern orientation in finite domains without boundaries

We investigate the orientation of nonlinear stripe patterns in finite domains. Motivated by recent experiments, we introduce a control parameter drop from supercritical inside a domain to subcritical outside without boundary conditions at the domain border. As a result, stripes align perpendicular to shallow control parameter drops. For steeper drops, non-adiabatic effects lead to a surprising orientational transition to parallel stripes with respect to the borders. We demonstrate this effect in terms of the Brusselator model and generic amplitude equations

Dimensions of Imaginary Root Spaces of Hyperbolic Kac--Moody Algebras

We discuss the known results and methods for determining root multiplicities for hyperbolic Kac--Moody algebras

Grain boundaries in ultrathin organic semiconductors

Organic semiconductors stand out over their inorganic counterparts, since they can be processed in thinner films and at lower energies, onto nearly any surface, and with tunable optical and electrical properties for specific purposes. These unique properties of organic semiconductors allow to save material, energy, space and cost and make them ideal for applications in customer-specific end-products. Although organic semiconductors have been implemented in semiconductor devices such as organic solar-cells, organic light-emitting diodes, organic field-effect transistors or sensors for years, these devices still show inferior performances compared to inorganic devices, especially in terms of reduced mobility, efficiency, reproducibility and stability. It is widely accepted that grain boundaries in organic semiconductors are one of the main responsibles for these drawbacks, since they act as trapping, recombination and/or degradation sites. However, why and how grain boundaries emerge (structurally and energetically), and which properties of grain boundaries mainly influence the device performance is still under investigation. Since addressing these questions will help to control charge transport in organic semiconductors and improve device performance, this work presents a fundamental investigation of grain boundaries in monolayer-thin films of an organic small molecule. These films stand out due to high crystallinity and atomically smoothness across grain boundaries. This, as well as their thinness, allows to characterize single grains and grain boundaries at the location where charge transport takes place in organic field-effect transistors, namely at the semiconductor-insulator interface. By Kelvin probe force microscopy (KPFM) grain boundaries are found as a first result to act as energy barriers or valleys, and different thin-film application techniques are presented resulting in films in which either a specific type of grain boundary predominates, or in films where barriers and valleys coexist. While it is particularly advantageous for future experiments to be able to control the existence of different types of grain boundaries in organic materials, the films with both types prove the fundamental difference between energy barriers and valleys. KPFM measurements not only allow a qualitative differentiation of barriers and valleys, but also a quantitative description of „grain boundary heights“. Valley depths and barrier heights can both be decreased by increasing the charge-carrier density in the organic semiconductor-film. However, they only vanish at charge-carrier densities above the typical operating regime of organic solar-cells and organic light-emitting diodes, which underlines the relevance of investigating charge transport at grain boundaries. Consequently, time-resolved KPFM measurements are conducted to investigate the trapping and detrapping mechanisms at grain boundaries and other local impurities, as well as their influence on global device parameters. While valleys trap charge carriers in deep traps, barriers backscatter electrons, but also indicate an increased trap-state density at the organic-semiconductor interface, thereby leading to a stronger reduction of charge transport than valleys. Valleys, on the contrary, are found to mainly define the global device parameters such as the turn-on and threshold voltage or the qualitative behavior of hysteresis. This finding underlines the need to be able to control not only the grain-boundary density in organic semiconductors, but also their type and absolute height. However, since it is challenging to control the emergence and electric properties of grain boundaries in organic semiconductors by experimental methods, an alternative experiment is presented with the aim to manipulate charge transport across grain boundaries by illumination with far-infrared light. It is assumed that photons from this light source are absorbed, leading to the excitation of charge carriers out of valleys or across barriers and thus to a measurable photocurrent. This photocurrent can be measured energy-resolved by using a modified Fourier transform infrared spectrometer, which allows to detect and characterize grain boundaries even in bulk-like materials. Finally, charge transport in a novel metal-organic framework is investigated directionally, globally and locally, to put the role of grain boundaries in organic semiconductors into a context. It is found that in this special material grain boundaries do not play an as important role as the stacking direction of single planes of the metal-organic framework. To summarize, the findings of this work lead toward controlling the properties of grain boundaries in organic semiconductors and their role in organic semiconductor devices such as field-effect transistors, organic solar-cells or organic light-emitting diodes

Transcending borders: Strategic engagement with cultural heritage organizations in Mexico at San Diego State University

In 2022, San Diego State University (SDSU), located in San Diego, California, USA, established the SDSU Center for Mesoamerican Studies as part of its strategic commitment to establish academic partnerships with institutions of higher education and other cultural heritage organizations in Mexico. As a key contributor to this strategic goal of the university, the SDSU Library has established new partnerships around teaching and learning services, digital collections, and professional development with institutions including the Instituto Municipal de Arte y Cultura in Tijuana and the Biblioteca de Investigación Juan de Córdova in Oaxaca. This paper will provide an introduction to the institutional vision for strategic collaboration with Mexican institutions as part of a broader internationalization strategy and highlight current partnership activities focused on digitization and digital collections, discovery and access to faculty and student scholarship reflecting the university interests in Oaxaca, and shared approaches to professional development of library and archives staff

Estimation of CO2 release from thermal springs to the atmosphere

Introduction Geodynamically active regions have long been recognized as areas of anomalous Earth degassing [Irwin and Barnes, 1980]. Areas found at plate boundaries are characterized by seismic, volcanic and geothermal activity as well as ore deposition. These processes are enhanced by the circulation of hydrothermal fluids in the crust, which transport volatiles from the deep crust or mantle to the surface [King, 1986]. Kerrick and Caldera, [1998], were the first to indicate the significant contribution of the CO2 degassing by extensional tectonic and hydrothermal activity in metamorphic belts during the Phanerozoic. Moreover, further studies concerning gas emissions from diffuse degassing tectonic structures on various geological regimes suggested in their majority elevated CO2 concentrations [Klusman, 1993]. In fact, it is worth noting that the estimated global hydrothermal CO2 flux from subaerial geothermal environments can be comparable to that of direct volcanic discharges [Kerrick et al., 1995; Seward and Kerrick, 1996]. Study Area The back-arc geothermal fields of Greece include, among others, the Tertiary sedimentary basins of both Sperchios Basin and north Euboea, which are located in central Greece. Their tectonic activity contributes in crust thinning [Papadakis at al., 2016 and references therein] and elevated heat flow values [Fytikas and Kolios, 1979]. These geothermal anomalies due to the tectonic activity and the geological and volcanic regime are expressed as hot springs (Ypatis, Psoroneria, Thermopyles and Kamena Vourla in Sperchios Basin and Edipsos and Ilion in north Euboea). Tectonics of central Greece seems to be of particular interest as major fault structures are found in the area. Sperchios Basin was formed through the activity of WNW-ESE trending faults [Georgalas and Papakis, 1966; Marinos et al., 1973], whilst the Sperchios tectonic graben itself is considered to be the extension of the North Anatolia strike-slip fault. Moreover, in the north Euboean Gulf, the major fault structures are those of the Atalanti Fault Zone (AFZ) that consist of several segments of normal faults, trending about NW-SE [Pavlides et al., 2004]. Materials and Methods Six groups of springs (Ypatis, Psoroneria, Thermopyles, Kamena Vourla, Edipsos and Ilion) were investigated in this study. Bubbling gases were sampled using an inverted funnel positioned above the bubbles and stored in glass flasks equipped with two stopcocks until analysis. Samples for dissolved gas analyses were collected in glass vials and were sealed underwater. In the laboratory, the concentrations of He, H2, H2S, O2, N2, CO2 and CH4, on the samples were analysed by an Agilent 7890B gas chromatograph with Ar as carrier. The total CO2 emitted through bubbling was measured at 6 different pools (Psoroneria, Psoroneria 2,Thermopyles, Leonidas, Kamena Vourla and Ilion), whereas at other springs (Koniavitis-Sperchios Basin, Edipsos-Damaria and Edipsos-Thermopotamos) an estimation of the release was made by visual inspection. The CO2 fluxes were measured using the floating chamber method [Mazot and Bernard, 2015] that was equipped with a portable fluxmeter (WEST Systems, Italy) based on the accumulation chamber method as suggested by Chiodini et al., [1998]. The flux data were processed with both the Graphical Statistical Approach (GSA) and the Stochastic Simulation Approach (SSA), with the latter being based on the algorithm of sequential Gaussian simulation [Deutsch and Journal 1998; Cardellini et al., 2003]. Zonal Statistics on the final CO2 flux maps was obtained using the ArcMap 10.3 (ESRI) Spatial Analyst tool and were used to estimate the total CO2 output to the atmosphere. Results and Conclusions Carbon dioxide is the prevailing gas species for the great majority of the under investigation sites, with only gases collected in the area of Kamena Vourla (Kamena Vourla and Koniavitis) being rich in N2. The total bubbling CO2 emission from the pools to the atmosphere ranged from 314 to 44,800 g/m2/day. At sites with greater surfaces, the CO2 release was estimated after performing direct measurements (28-Thermopyles, 74-Psoroneria) with the most elevated values being found in the areas of Thermopyles and Psoroneria (1 and 2 t/d, respectively) (Tab. 1); the maps were drawn following the SSA (Figure 1). The outgoing channels of the springs showed an elevated flow (> 250 l/s) of gas-charged water (> 15 mmol/l of dissolved CO2). Even though no bubbling was visible along the stream, the dissolved CO2 content sampled at different distances from springs of Psoroneria and Thermopyles, decreased up to an order of magnitude after few hundreds of metres, indicating an evident and intense, although not visible, CO2 degassing versus the atmosphere. Physico-chemical parameters (temperature and pH) along the outlet channels were also measured at the same sampling points showing correlations (negative in terms of temperature; T decreased from 33.1 to 30.3 and 40.8 to 39 °C, respectively and positive in terms of pH; pH increased from 6.11 to 7.05 and 6.05 to 7.70, respectively) with the distance. The CO2 output of the outgoing channels to the atmosphere was quantified considering thedifference between the initial and the final content of the dissolved CO2 as well as the water flow, obtaining values of > 10 t/d for Thermopyles and ~9 t/d for Psoroneria. Estimations were also made at Ypatis, Kamena Vourla, Koniavitis and Edipsos, where the mean values reached 1 t/d of CO2 for each spring. The obtained CO2 released from the bubbling pools to the atmosphere was directly compared with the one estimated from the outgoing channels (Tab. 1). The degassing along the outflow channel was almost always higher than the corresponding bubbling pool, sometimes even an order of magnitude, suggesting that most of the degassing is “hidden”. For each site the amount of CO2 released versus the atmosphere was calculated as (Figure 2): ΦtotCO2 = Φpool + Φstream The total CO2 released to the atmosphere as estimated for the study area is at ~ 30 t/d, with the major contribution deriving from the degassing along the outflow channels of the thermal springs. Such output is comparable and sometimes higher than that of each single active volcanic system along the South Aegean Volcanic Arc (15 - 38 t/d) and highlights the importance of “hidden” degassing along CO2 - oversaturated streams

Microbial impact on the isotope composition of methane in both thermal and hyperalkaline waters of central Greece

Introduction The different origins of methane can be subdivided in biogenic (either directly produced by microbial activity or deriving by decay of organic matter at T > 150\ub0C) and abiogenic (from pure inorganic reactions). Among the latter, one of the most debated origins comes from serpentinization processes of ultramafic rocks in ophiolitic sequences at low temperatures (T < 80 \ub0C). Moreover, further secondary processes (diffusion, inorganic or microbial oxidation, etc.) may also contribute and thus mask the original chemical and/or isotope composition. Primary and secondary processes acting on CH4 can be recognised mainly through its isotope (d13C and d2H) composition and the ratio between CH4 and C2+C3 light hydrocarbons [Bernard et al. 1978; Schoell 1980]. Microorganisms may be involved in the methane cycle not only as active producers but also as consumers. Methane oxidizing bacteria (or methanotrophs) are microorganisms with the ability to use methane as the only source of carbon for energy and biomass production. Methanotrophs are ubiquitous and play an important role in the global carbon cycle, acting as a natural filter between the subsoil and the atmosphere. They were isolated from several environments such as soils, wetlands, freshwater, marine sediments, water columns, groundwater, rice paddies, and peat bogs [Murrell and Jetten, 2009]. Some species were adapted also at extreme environments characterized by high temperature (up to 81.6 \ub0C), extremely low or high pHs (1.5-11) or even anaerobic conditions. Due to the fact that methanotrophs metabolize preferentially light isotopes, biologic methane oxidation brings sometimes to extremely positive d13C and d2H values [Cadieux et al., 2016]. The Greek territory belongs to the geodynamically active Alpine-Himalayan orogenic belt. As such, it shows intense seismic activity, active volcanic systems and areas of enhanced geothermal fluxes. One of these areas is the Sperchios Basin and the northern part of Euboea Island in central Greece, where thermal manifestations are widespread [D\u2019Alessandro et al., 2014]. The complex geology of Greece includes also two important parallel running ophiolitic belts, with the Othrys Massif (central Greece) belonging to the westernmost of them. In and around this wide ophiolite outcrop, some cold hyperalkaline and some hypothermal (T < 30\ub0C) alkaline waters are present. In the present paper we discuss data about chemistry and methane isotope composition of bubbling or dissolved gases in both thermal springs and hyperalkaline springs of Central Greece. Sampling and Analytical Methods Free bubbling gas samples were taken using an inverted funnel. All free gas samples were stored in Pyrex bottles with two vacuum stopcocks. Samples for dissolved gas analyses were collected in glass vials sealed underwater. In the laboratory, the chemical analyses were carried out by gaschromatography (Agilent 7890B GC System) using Ar as the carrier gas. Dissolved gases were extracted after equilibrium was reached at constant temperature with a host-gas (high-purity argon) injected in the sample bottle. The measurement precision was better than \ub15% for common gases and \ub110% for trace gases such as the alkanes. The chemical composition of the dissolved gas phase was obtained from the gas-chromatographic analyses taking into account the solubility coefficients (Bunsen coefficient \u201c\u3b2\u201d, ccgas/mlwater STP) of each gas specie, the volume of gas extracted and the volume of the water sample (details in Capasso and Inguaggiato, [1998] and Liotta and Martelli, [2012]). Starting from the total amount of dissolved gases (ccSTP/L) we calculated the relative abundances for every single gas species in equilibrium with the dissolved gas phase and expressed the analytical results in \u3bcmol/mol of gas at atmospheric pressure, allowing the comparison of dissolved gases with free gases. Carbon and hydrogen isotope compositions of CH4 were measured using a Thermo TRACE GC and a Thermo GC/C III interfaced to a Delta Plus XP gas source mass spectrometer. 13C/12C ratios are reported here as d13C values (\ub10.1 \u2030) with respect to the V-PDB standard. 1H/2H ratios are reported here as d2H values (\ub12 \u2030) with respect to the V-SMOW standard. The oxygen and hydrogen isotopic compositions of water were analysed on unfiltered samples with the use of Analytical Precision AP 2003 and FinniganMAT Delta Plus IRMS devices, respectively. The isotope ratios are expressed as the deviation per mil (\u3b4\u2030) from the reference V-SMOW. The uncertainties (\ub11\u2030 were \ub10.1% for \u3b418O and \ub11% for \u3b42H. Results Five thermal springs, with temperatures from 33 to 80\ub0C, were sampled in the study area. All show elevated fluxes of bubbling gases whose prevailing species are either CO2 or N2. Methane concentrations range from 27 to 4000 \u3bcmol/mol, whilst the isotope composition of CH4 covers a wide range with d13C values ranging from -21.7 to +16.9\u2030 and d2H values ranging from -124 to +370\u2030. Seven alkaline hypothermal waters were collected in five areas (Amplas, Platystomo, Kaitsa, Smokovo and Soulanta) while 10 hyperalkaline waters in two areas (Archani and Ekkara); all samples were collected from different springs and wells and some of the sites presented bubbling. All samples present low concentrations of H2 (from <2 to 2500 \u3bcmol/mol), CO2 (up to 26,000 but generally below 1000 \u3bcmol/mol) and O2 (up to 16,000 but generally below 3000 \u3bcmol/mol). Gases in alkaline waters (pH <10) are in their majority dominated by CH4 (from 128,000 to 915,000 \u3bcmol/mol). Hyperalkaline (pH > 11) waters are N2 dominated (from 727,000 to 977,000 \u3bcmol/mol) and have CH4 concentrations from 11,500 to 279,000 \u3bcmol/mol. Also all these samples display a wide range of isotope compositions of CH4 (d13C from -74.5 to -14.5 \u2030 and d2H from -343 to -62 \u2030). Discussion Thermal springs Methane in most of the bubbling gases found in the thermal waters of Greece display a small range in isotope composition close to -21\u2030 for carbon and to -130\u2030 for hydrogen [Daskalopoulou et al., 2018] and plot in the middle of the field of volcanic and geothermal systems (Figure 1). In the study area, only the hottest (Edipsos) of the thermal manifestations displays similar values. All the remaining samples fit a methane oxidation trend reaching extremely positive values (Figure 1). If we consider the lowest values as the deep hydrothermal marker the obtained \u394H/\u394C values range between 5 and 13 which are close to those typical of microbially driven oxidation [Coleman et al., 1981]. Although the outlet temperature of the hottest manifestations is at the upper limit for methanotrophic microrganisms [Sharp et al., 2014], we can hypothesize that environmental conditions are not favourable for their survival at this site. On the contrary, methanotrophs can thrive in the sites characterized by lower temperatures (33-65 \ub0C), strongly consuming methane. The most positive values were measured at Psoroneria and indicate a very high consumption fraction. Considering again the values of Edipsos as the deep hydrothermal marker, a Rayleigh fractionation modelling in a closed system and kinetic fractionation factors for microbial oxidation [Coleman et al., 1981] we estimate a consumption of more than the 75% of the initial CH4. Alkaline and hyperalkaline waters Alkaline waters present mostly isotope values for CH4 compatible with a biogenic origin (d13C from - 62.0 to -37.5 \u2030 and d2H from -247 to -154 \u2030). Only the sample of Kaitsa falls above the biogenic field, indicating possible fractionation due to CH4 oxidation (Figure 2). Most of the hyperalkaline waters have CH4 isotope values compatible with an abiogenic origin through serpentinization processes (Figure 2). But some of the CH4 collected in the hyperalkaline waters show values falling in the biogenic field, with at points, very negative d13C values (< -70\u2030). Methanogens were found also in other hyperalkaline waters taking advantage of the presence of sometimes very high hydrogen concentrations [Woycheese et al., 2015; Miller et al., 2018]. Also methanotrophs were rarely found in hyperalkaline waters [Woycheese et al., 2015; Miller et al., 2018] and their presence may justify the most positive values found in the study area (Figure 2)

Observing compact quark matter droplets in relativistic nuclear collisions

Compactness is introduced as a new method to search for the onset of the quark matter transition in relativistic heavy ion collisions. That transition supposedly leads to stronger compression and higher compactness of the source in coordinate space. That effect could be observed via pion interferometry. We propose to measure the compactness of the source in the appropriate principal axis frame of the compactness tensor in coordinate space

PRODUCER VALUATION OF HERD BULL CHARACTERISTICS

This study evaluates the importance of certain bull characteristics (disposition, EPD's, conformation, etc.) on a cow-calf producer's herd bull purchase decision. Data were collected from the Auburn University Bull Test Sale from 1997 to 2004. A total of 260 buyers purchased a total of 370 bulls during this six-year period. These buyers will be surveyed to determine demographics, farm characteristics, and the importance of factors influencing their bull purchase decision. A hedonic pricing model will be utilized to determine the value that individual buyers place on various factors or bull characteristics when purchasing a bull.Livestock Production/Industries,