Prevalence of alkane monooxygenase genes in Arctic and Antarctic hydrocarbon-contaminated and pristine soils

The prevalence of four alkane monooxygenase genotypes (Pseudomonas putida GPo1, Pp alkB; Rhodococcus sp. strain Q15, Rh alkB1 and Rh alkB2; and Acinetobacter sp. strain ADP-1, Ac alkM) in hydrocarbon-contaminated and pristine soils from the Arctic and Antarctica were determined by both culture-independent (PCR hybridization analyses) and culture-dependent (colony hybridization analyses) molecular methods, using oligonucleotide primers and DNA probes specific for each of the alk genotypes. PCR hybridization of total soil community DNA detected the rhodococcal alkB genotypes in most of the contaminated (Rh alkB1, 18/20 soils; Rh alkB2, 13/20) and many pristine soils (Rh alkB1, 9/10 soils; Rh alkB2, 7/10), while Pp alkB was generally detected in the contaminated soils (15/20) but less often in pristine soils (5/10). Ac alkM was rarely detected in the soils (1/30). The colony hybridization technique was used to determine the prevalence of each of the alk genes and determine their relative abundance in culturable cold-adapted (5°C) and mesophilic populations (37°C) from eight of the polar soils. The cold-adapted populations, in general, possessed relatively higher percentages of the Rh alkB genotypes (Rh alkB1, 1.9% (0.55); Rh alkB2, 2.47% (0.89)), followed by the Pp alkB (1.13% (0.50)), and then the Ac alkM (0.53% (0.36)). The Rh alkB1 genotype was clearly more prevalent in culturable cold-adapted bacteria (1.9% (0.55)) than in culturable mesophiles (0.41 (0.55)), suggesting that cold-adapted bacteria are the predominant organisms possessing this genotype. Overall, these results indicated that (i) Acinetobacter spp. are not predominant members of polar alkane degradative microbial communities, (ii) Pseudomonas spp. may become enriched in polar soils following contamination events, and (iii) Rhodococcus spp. may be the predominant alkane-degradative bacteria in both pristine and contaminated polar soil

Momentum-resolved electronic structure at a buried interface from soft x-ray standing-wave angle-resolved photoemission

Angle-resolved photoemission spectroscopy (ARPES) is a powerful technique for the study of electronic structure, but it lacks a direct ability to study buried interfaces between two materials. We address this limitation by combining ARPES with soft x-ray standing-wave (SW) excitation (SWARPES), in which the SW profile is scanned through the depth of the sample. We have studied the buried interface in a prototypical magnetic tunnel junction La0.7Sr0.3MnO3/SrTiO3. Depth- and momentum-resolved maps of Mn 3d eg and t2g states from the central, bulk-like and interface-like regions of La0.7Sr0.3MnO3 exhibit distinctly different behavior consistent with a change in the Mn bonding at the interface. We compare the experimental results to state-of-the-art density-functional and one-step photoemission theory, with encouraging agreement that suggests wide future applications of this technique.Comment: 18 pages, 4 figures and Supplementary Informatio

Attentive Learning of Sequential Handwriting Movements: A Neural Network Model

Defense Advanced research Projects Agency and the Office of Naval Research (N00014-95-1-0409, N00014-92-J-1309); National Science Foundation (IRI-97-20333); National Institutes of Health (I-R29-DC02952-01)

On a coupled PDE model for image restoration

In this paper, we consider a new coupled PDE model for image restoration. Both the image and the edge variables are incorporated by coupling them into two different PDEs. It is shown that the initial-boundary value problem has global in time dissipative solutions (in a sense going back to P.-L. Lions), and several properties of these solutions are established. This is a rough draft, and the final version of the paper will contain a modelling part and numerical experiments

Economic analysis of soilless and soil-based greenhouse cucumber production in Turkey

Since the onset of the commercial application of soilless culture, this production approach has evoluted at a fast pace, gaining popularity among growers throughout the world. As a result, a lot of information has been developed by growers, advisors, researchers, and suppliers of equipment and substrate. This study aimed to determine the cost and return of soilless greenhouse cucumber (Cucumis sativus L.) production and to prepare a sample budget for growers. Soilless cultivation is an alternative production method for Turkish growers and it is being practised on a commercial basis on 180 ha. Cost and return budgets can be useful for growers because they allows growers to compare total production cost and revenue varying grower type, production time, geographical location, operation size, and cost structure. Growers can identify items in their budget that have a greater effect on profitability, and make adjustments. In this study, economic aspects of soilless and soil-based greenhouse cucumber production was analysed as comparative. Total costs were subtracted from total gross revenue to calculate the net return of soilless and soil-based greenhouse cucumber production. The cost items of soilless and soil-based greenhouse cucumber production were initial investment costs, variable costs, and fixed costs. Net return obtained from cucumbers grown in a mixture of perlite and zeolite was determined as € 1.84 m-2, whereas it was € 1.48 m-2 in conventional soil-based production. Production and market risks both affect profitability and economic viability of soilless grown vegetables.Desde o início da implantação de cultivos comerciais sem solo suas técnicas de produção tem evoluido em ritmo acelerado, ganhando popularidade entre agricultores de todo o mundo. Como resultado, uma grande quantidade de informação tem sido desenvolvida pelos produtores, consultores, pesquisadores e fornecedores de equipamentos e substratos. Determinaram-se o custo e retorno financeiro da produção de pepino (Cucumis sativus L.) e preparou-se um exemplo de orçamento para produtores. Na Turquia o cultivo sem solo é um método alternativo de produção para agricultores e é praticado em bases comerciais em 180 hectares. Por conseguinte, avaliações de custos e retornos podem ser úteis para produtores porque permitem aos mesmos comparar o custo total da produção e o retorno segundo variações de tipo de olericultor, tempo de produção, localização geográfica, tamanho do empreendimento e custo das estruturas. Os produtores podem assim identificar quais itens em seus orçamantos tem maior efeito na rentabilidade e fazer ajustes. Nesse estudo aspectos econômicos de cultivos de pepino em casas de vegetação sem solo e com solo foram analisados e comparados.Os custos totais foram subtraidos das receitas brutas para fins de cálculo do retorno líquido de produções de pepino em cultivos com e sem solo. Os custos dos itens dos cultivos com e sem solo foram: investimentos iniciais, custos variáveis e custos fixos. O retorno líquido obtido pelos produtores de pepino cultivados em um substrato de perlita e zeolita foi de € 1.84 m-2 e de € 1.48 m-2 para o cultivo convencional com solo. Contudo, riscos de produção e de mercado afetam a rentabilidade e viabilidade econômica de hortaliças cultivadas sem solo

The ELFIN mission

The Electron Loss and Fields Investigation with a Spatio-Temporal Ambiguity-Resolving option (ELFIN-STAR, or heretoforth simply: ELFIN) mission comprises two identical 3-Unit (3U) CubeSats on a polar (∼93∘ inclination), nearly circular, low-Earth (∼450 km altitude) orbit. Launched on September 15, 2018, ELFIN is expected to have a >2.5 year lifetime. Its primary science objective is to resolve the mechanism of storm-time relativistic electron precipitation, for which electromagnetic ion cyclotron (EMIC) waves are a prime candidate. From its ionospheric vantage point, ELFIN uses its unique pitch-angle-resolving capability to determine whether measured relativistic electron pitch-angle and energy spectra within the loss cone bear the characteristic signatures of scattering by EMIC waves or whether such scattering may be due to other processes. Pairing identical ELFIN satellites with slowly-variable along-track separation allows disambiguation of spatial and temporal evolution of the precipitation over minutes-to-tens-of-minutes timescales, faster than the orbit period of a single low-altitude satellite (Torbit ∼ 90 min). Each satellite carries an energetic particle detector for electrons (EPDE) that measures 50 keV to 5 MeV electrons with Δ E/E 1 MeV. This broad energy range of precipitation indicates that multiple waves are providing scattering concurrently. Many observed events show significant backscattered fluxes, which in the past were hard to resolve by equatorial spacecraft or non-pitch-angle-resolving ionospheric missions. These observations suggest that the ionosphere plays a significant role in modifying magnetospheric electron fluxes and wave-particle interactions. Routine data captures starting in February 2020 and lasting for at least another year, approximately the remainder of the mission lifetime, are expected to provide a very rich dataset to address questions even beyond the primary mission science objective.Published versio

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease