Galactic Cosmic Rays from Superbubbles and the Abundances of Lithium, Beryllium, and Boron

In this article we study the galactic evolution of the LiBeB elements within the framework of a detailed model of the chemical evolution of the Galaxy that includes galactic cosmic ray nucleosynthesis by particles accelerated in superbubbles. The chemical composition of the superbubble consists of varying proportions of ISM and freshly supernova synthesized material. The observational trends of 6 LiBeB evolution are nicely reproduced by models in which GCR come from a mixture of 25% of supernova material with 75% of ISM, except for 6 Li, for which maybe an extra source is required at low metallicities. To account for 7 Li evolution several additional sources have been considered (neutrino-induced nucleosynthesis, nova outbursts, C-stars). The model fulfills the energetic requirements for GCR acceleration.Comment: 25 pages, 9 figures. Accepted for publication in the Astrophysical Journa

Conservation Status of the Plains Spotted Skunk, Spilogale putorius interrupta, in Texas, with an Assessment of Genetic Variability in the Species

Robert C. Dowler, Department of Biology at Angelo State University is the corresponding author, robert dot dowler at angelo dot eduIn this report, we present results of research on the conservation status of the plains spotted skunk (Spilogale putorius interrupta) in Texas and an assessment of the genetic variability in populations throughout the range of the species. The conservation status portion of the study included (1) mapping the species’ potential habitat in Texas using maximum entropy modeling (Maxent) with historic museum specimen records, (2) field-based surveying of locations in 10 counties to determine occurrence of the plains spotted skunk, (3) seeking additional occurrence records in Texas through crowd sourcing and citizen scientist approaches (4) using all current (2001 – 2017) occurrences to produce a model of probable geographic distribution in Texas and (5) assessing anthropogenic changes in land use, which may threaten the species’ habitats, by mapping current and forecasted oil and gas development and urbanization within the species’ modeled range. The species distribution model, combined with the land-change assessment, was used to select sites in 10 representative counties for field-based surveys in the hopes of revealing patterns of current distribution. Field surveys were carried out using live traps, enclosed track plates, and camera traps. These methods documented detections of plains spotted skunks (n = 12) in 4 of the 10 sites sampled. All methods of detection were successful, but cameras and live traps out-performed track plates. Crowd-sourced approaches and citizen scientist camera trapping revealed an additional 82 occurrences in the state, 79 of which were since 2009. These recent records were used to produce a species distribution model that provides relative probability of occurrence for the plains spotted skunk in the state. Our land-change mapping revealed potential anthropogenic threats to habitats at 2 of the sites (Katy Prairie and Fort Hood), which also had robust populations of plains spotted skunks based on 25 and 51detections, respectively). For our genetic assessment, samples of tissue from three sources (i.e., field surveys, state agencies throughout the distribution of the eastern spotted skunk, and museum tissue collections) allowed a detailed assessment of the genetic variability in the species (S. putorius) using both microsatellite markers and cytochrome b gene sequence. Our analysis of 119 specimens was able to establish that genetic patterns were consistent with currently accepted taxonomy of the 3 recognized subspecies of S. putorius (S. p. putorius, S. p. ambarvalis, and S. p. interrupta). We also determined that there was no evidence for hybridization with the congener, S. gracilis (western spotted skunk), a species co-occurring with the eastern spotted skunk in parts of Texas. The differentiation between S. p. putorius and S. p. ambarvalis was less pronounced (FST = 0.178; cytochrome b sequence divergence = 1.2%) than between these subspecies and the plains spotted skunk (average FST = 0.278; cytochrome b sequence divergence = 2.9%). Overall, genetic variability (observed heterozygosity = 0.474) in the plains spotted skunk was lower than that seen in common carnivores (striped skunks, raccoons), but slightly higher than some endangered carnivores (black-footed ferret). The heterozygosity levels more closely resemble the levels found within the island spotted skunk (S. gracilis amphiala) from the Channel Islands of California and other vertebrates that have a “threatened” conservation status. Key findings of the study include: 1) the current geographic distribution of the plains spotted skunk in Texas is reduced relative to historic records; 2) the species distribution model based on recorded occurrences since 2001 suggests areas of the state that are in need of further survey efforts; 3) genetic variability of plains spotted skunks is lower than more common carnivores, but higher than some recognized endangered species; 4) the subspecies, S. p. interrupta is a distinct genetic subunit of the eastern spotted skunk; and 5) continued energy development and especially future urbanization in some parts of Texas may affect populations of the plains spotted skunk.Texas Comptroller of Public AccountsBureau of Economic Geolog

Non-syndromic Hearing Impairment in a Hungarian Family with the m.7510T>C Mutation of Mitochondrial tRNA^^Ser(UCN)^^^ and Review of Published Cases

The m.7510T>C mitochondrial DNA (mtDNA) mutation is a tRNA(Ser(UCN)) alteration leading to matrilineal isolated hearing impairment. The current paper reviews the available reports on the m.7510T>C mtDNA mutation, with special attention to phenotypic variations and haplogroup background. A Hungarian family, the fourth family reported in the literature, is presented, in which analysis of three generations with bilateral isolated hearing loss revealed the m.7510T>C tRNA(Ser(UCN)) mutation in homoplasmic form in the affected members. Haplogroup analysis verified an unnamed subgroup of mitochondrial haplogroup H. Previously reported Spanish and North American Caucasian families belong to different subgroups of haplogroup H. Analyzing our biobank of Hungarian patients with sensorineural hearing loss, we did not detect this mutation in any other patient, nor was it found in Caucasian haplogroup H control samples. Comparing the cases reported so far, there is interfamilial variablity in the age of onset, accompanying symptoms, and haplogroup background. Our case adds further genetic evidence for the pathogenicity of the m.7510T>C mutation and underlines the need to include full mtDNA sequencing in the screening for unexplained hearing loss

Assessing Historical Fish Community Composition Using Surveys, Historical Collection Data, and Species Distribution Models

Accurate establishment of baseline conditions is critical to successful management and habitat restoration. We demonstrate the ability to robustly estimate historical fish community composition and assess the current status of the urbanized Barton Creek watershed in central Texas, U.S.A. Fish species were surveyed in 2008 and the resulting data compared to three sources of fish occurrence information: (i) historical records from a museum specimen database and literature searches; (ii) a nearly identical survey conducted 15 years earlier; and (iii) a modeled historical community constructed with species distribution models (SDMs). This holistic approach, and especially the application of SDMs, allowed us to discover that the fish community in Barton Creek was more diverse than the historical data and survey methods alone indicated. Sixteen native species with high modeled probability of occurrence within the watershed were not found in the 2008 survey, seven of these were not found in either survey or in any of the historical collection records. Our approach allowed us to more rigorously establish the true baseline for the pre-development fish fauna and then to more accurately assess trends and develop hypotheses regarding factors driving current fish community composition to better inform management decisions and future restoration efforts. Smaller, urbanized freshwater systems, like Barton Creek, typically have a relatively poor historical biodiversity inventory coupled with long histories of alteration, and thus there is a propensity for land managers and researchers to apply inaccurate baseline standards. Our methods provide a way around that limitation by using SDMs derived from larger and richer biodiversity databases of a broader geographic scope. Broadly applied, we propose that this technique has potential to overcome limitations of popular bioassessment metrics (e.g., IBI) to become a versatile and robust management tool for determining status of freshwater biotic communities

Recuperação hidrofóbica de polipropileno tratado por VUV ou plasma

Tratamentos superficiais por plasma e ultravioleta de vácuo (VUV) foram utilizados para introduzir grupos funcionais contendo oxigênio em amostras de polipropileno, com objetivo de modificar sua molhabilidade. Análises por ATR-FTIR, AFM e ângulo de contato (AC) foram utilizadas para analisar as mudanças químicas e físicas na superfície do PP em função do tempo. Os resultados mostraram que as mudanças na molhabilidade das amostras tratadas por VUV ocorreram principalmente devido à alteração química da superfície. Nas amostras tratadas por plasma, o envelhecimento ocorreu mais rapidamente que as amostras tratadas por VUV. Para ambos os tratamentos, provavelmente ocorreu um rearranjo das cadeias durante o envelhecimento, além de uma possível reticulação da superfície na amostra tratada por VUV