Direct evidence of electron spin polarization from an organic-based magnet: [FeII(TCNE)(NCMe)2][FeIII Cl4]

Journal ArticleDirect evidence of an organic-based magnet with a finite electron spin polarization at the Fermi edge is shown from spin-resolved photoemission of the [FeII(TCNE)(NCMe)2][FeIIICl4] organic-based magnet. The 23% majority-based spin polarization at the Fermi edge is observed at 80 K in zero applied field. Ab initio calculations at the density functional level (O K) are in accord with a semiconductor with 100% majority-based electron spin polarization at the band edges, commensurate with our experimental results and model prediction for a half-semiconductor. Organic-based magnets may prove to be important for realizing polarized electron injection into semiconductors for magnetoelectronic applications

Concepts for radically increasing the numerical convergence rate of the Euler equations

Integral equation and finite difference methods have been developed for solving transonic flow problems using linearized forms of the transonic small disturbance and Euler equations. A key element is the use of a strained coordinate system in which the shock remains fixed. Additional criteria are developed to determine the free parameters in the coordinate straining; these free parameters are functions of the shock location. An integral equation analysis showed that the shock is located by ensuring that no expansion shocks exist in the solution. The expansion shock appears as oscillations in the solution near the sonic line, and the correct shock location is determined by removing these oscillations. A second objective was to study the ability of the Euler equation to model separated flow

Micro-X-Ray Fluorescence and the Old Masters: Non-destructive in situ characterisation of the varnish of historical Low Countries stringed musical instruments

In recent years, a growing attention has been addressed to the study of the varnish from early musical instruments. The surfaces of nine historical Low Countries stringed musical instruments from the collection of the "Musical Instruments Museum” in Brussels were non-destructively analysed by in situ micro-X-Ray Fluorescence spectroscopy in dispersive mode. It was found that the main pigments dispersed in the varnish were iron- and manganese-based earths. The presence of a chromium-based pigment in one of the analysed instruments makes it appreciably different from the others. Other findings were discussed and compared with previously published results. The collection of such information plays a relevant role in the recovery of the applied formulations that is an interesting issue for conservators, luthiers and art historian

The transcriptional regulator CtrA controls gene expression in Alphaproteobacteria phages: Evidence for a lytic deferment pathway

Pilitropic and flagellotropic phages adsorb to bacterial pili and flagella. These phages have long been used to investigate multiple aspects of bacterial physiology, such as the cell cycle control in the Caulobacterales. Targeting cellular appendages for adsorption effectively constrains the population of infectable hosts, suggesting that phages may have developed strategies to maximize their infective yield. Brevundimonas phage vB_BsubS-Delta is a recently characterized pilitropic phage infecting the Alphaproteobacterium Brevundimonas subvibrioides. Like other Caulobacterales, B. subvibrioides divides asymmetrically and its cell cycle is governed by multiple transcriptional regulators, including the master regulator CtrA. Genomic characterization of phage vB_BsubS-Delta identified the presence of a large intergenic region with an unusually high density of putative CtrA-binding sites. A systematic analysis of the positional distribution of predicted CtrA-binding sites in complete phage genomes reveals that the highly skewed distribution of CtrA-binding sites observed in vB_BsubS-Delta is an unequivocal genomic signature that extends to other pilli- and flagellotropic phages infecting the Alphaproteobacteria. Moreover, putative CtrA-binding sites in these phage genomes localize preferentially to promoter regions and have higher scores than those detected in other phage genomes. Phylogenetic and comparative genomics analyses show that this genomic signature has evolved independently in several phage lineages, suggesting that it provides an adaptive advantage to pili/flagellotropic phages infecting the Alphaproteobacteria. Experimental results demonstrate that CtrA binds to predicted CtrA-binding sites in promoter regions and that it regulates transcription of phage genes in unrelated Alphaproteobacteria-infecting phages. We propose that this focused distribution of CtrA-binding sites reflects a fundamental new aspect of phage infection, which we term lytic deferment. Under this novel paradigm, pili- and flagellotropic phages exploit the CtrA transduction pathway to monitor the host cell cycle state and synchronize lysis with the presence of infectable cells

The transcriptional regulator CtrA controls gene expression in Alphaproteobacteria phages : Evidence for a lytic deferment pathway

Pilitropic and flagellotropic phages adsorb to bacterial pili and flagella. These phages have long been used to investigate multiple aspects of bacterial physiology, such as the cell cycle control in the Caulobacterales. Targeting cellular appendages for adsorption effectively constrains the population of infectable hosts, suggesting that phages may have developed strategies to maximize their infective yield. Brevundimonas phage vB_BsubS-Delta is a recently characterized pilitropic phage infecting the Alphaproteobacterium Brevundimonas subvibrioides. Like other Caulobacterales, B. subvibrioides divides asymmetrically and its cell cycle is governed by multiple transcriptional regulators, including the master regulator CtrA. Genomic characterization of phage vB_BsubS-Delta identified the presence of a large intergenic region with an unusually high density of putative CtrA-binding sites. A systematic analysis of the positional distribution of predicted CtrA-binding sites in complete phage genomes reveals that the highly skewed distribution of CtrA-binding sites observed in vB_BsubS-Delta is an unequivocal genomic signature that extends to other pilli- and flagellotropic phages infecting the Alphaproteobacteria. Moreover, putative CtrA-binding sites in these phage genomes localize preferentially to promoter regions and have higher scores than those detected in other phage genomes. Phylogenetic and comparative genomics analyses show that this genomic signature has evolved independently in several phage lineages, suggesting that it provides an adaptive advantage to pili/flagellotropic phages infecting the Alphaproteobacteria. Experimental results demonstrate that CtrA binds to predicted CtrA-binding sites in promoter regions and that it regulates transcription of phage genes in unrelated Alphaproteobacteria-infecting phages. We propose that this focused distribution of CtrA-binding sites reflects a fundamental new aspect of phage infection, which we term lytic deferment. Under this novel paradigm, pili- and flagellotropic phages exploit the CtrA transduction pathway to monitor the host cell cycle state and synchronize lysis with the presence of infectable cells

Ecohydrologic Connections in Semiarid Watershed Systems of Central Oregon USA

An improved understanding of ecohydrologic connections is critical for improving land management decisions in water-scarce regions of the western United States. For this study, conducted in a semiarid (358 mm) rangeland location in central Oregon, we evaluated precipitation-interception-soil moisture dynamics at the plot scale and characterized surface water and groundwater relations across the landscape including areas with and without western juniper (Juniperus occidentalis). Results from this study show that juniper woodlands intercepted up to 46% of total precipitation, altering soil moisture distribution under the canopy and in the interspace. Results indicate that precipitation reaching the ground can rapidly percolate through the soil profile and into the shallow aquifer, and that strong hydrologic connections between surface and groundwater components exist during winter precipitation and snowmelt runoff seasons. Greater streamflow and springflow rates were observed in the treated watershed when compared to the untreated. Streamflow rates up to 1020 L min(-1) and springflow rates peaking 190 L min(-1) were observed in the watershed where juniper was removed 13 years ago. In the untreated watershed, streamflow rates peaked at 687 L min(-1) and springflow rates peaked at 110 L min(-1). Results contribute to improved natural resource management through a better understanding of the biophysical connections occurring in rangeland ecosystems and the role that woody vegetation encroachment may have on altering the hydrology of the site

The 1995 Georges Bank Stratification Study and moored array measurements

The 1995 Geoges Bank Stratification Study (GBSS) was the first intensive process study conducted as part of the U.S. GLOBEC Northwest Atlantic/Georges Bank field program. The GBSS was designed to investigate the physical processes which control the seasonal development of stratification along the southern flank of Georges Bank during spring and summer. Past work suggested that during this period, larval cod and haddock tended to aggregate to the thermocline on the southern flank where higher concentrations of their copepod prey were found. A moored array was deployed as part of GBSS to observe the onset and evolution of sesonal stratification over the southern flank with sufficient vertical and horizontal resolution that key physical processes could be identified and quantified. Moored current, temperature, and conductivity (salinity) measurements were made at three sites along the southern flank, one on the crest, and one on the northeast peak of the bank. Moored surface meteorological measurements were also made at one southern flank site to determine the surface wind stress and heat and moisture fluxes. The oceanographic and meteorological data collected with the GBSS array during January-August 1995 are presented in this report. Meteorological data collected on National Data Buoy Center environmental buoys 44011 (Georges Bank), 44008 (Nantucket Shoals), and 44005 (Gulf of Maine) are included in this report for completeness and comparison with the GBSS southern flank meteorological measurements.Funding was provided by the National Science Foundation under Grant Numbers OCE-98-06379 and OCE-98-06445

Análisis del nivel de productividad por ausentismo en las empresas. Revisión de la literatura.

This paper analyzes how absenteeism negatively affects the achievement of the objectives set in the different areas of the companies, mainly in productivity. For the analysis, articles related to absenteeism and labor productivity, published between 2017 and 2021, generated by national and international authors, were taken as references, to which the research methodology, findings and conclusions were analyzed. Bibliographic databases such as Scopus, academic Google and Science were used, 25 articles were characterized and finally the 10 most relevant consulted citations on the topic under study were selected. Through the bibliographic review, the diverse documentary production regarding absenteeism and its influence on productivity was identified. More than 40% of the research found corresponds to areas of knowledge related to medicine, where the prevalent diseases among the working population with the highest degree of absenteeism are analyzed. However, there were very few texts that presented the causes associated with absenteeism that are not related to illnesses.  Once the analysis of the results presented by the different authors consulted has been completed, we can understand the relationship between absenteeism and productivity in organizations, the importance of continuous improvement in work processes and good management of the work environment, which are directly related to employees as the main focus of these studies. It is important to mention that each day of absenteeism of a collaborator represents high costs to the organization and for this reason it is recommended to implement health and safety programs at work, which help to minimize risks and improve the quality of life of employees.En el presente documento se analiza cómo el ausentismo afecta negativamente en el logro de los objetivos planteados en las diferentes áreas de las empresas, principalmente en la productividad. Para el análisis, se tomaron como referencias artículos relacionados con el ausentismo y la productividad laboral, publicados entre los años 2017 y 2021, generados por autores nacionales e internacionales, a los cuales se les analizó la metodología investigativa, sus hallazgos y conclusiones. Se utilizaron bases de datos bibliográficas como Scopus, Google académico y Science, se caracterizaron 25 artículos y finalmente se seleccionaron las 10 citas consultadas más relevantes sobre el tema en estudio. A través de la revisión bibliográfica se identificó la diversa producción documental con respecto al ausentismo y su influencia en la productividad. Más del 40% de las investigaciones encontradas corresponden a áreas del conocimiento relacionadas con la medicina, donde se analizan las enfermedades prevalentes entre la población trabajadora que presenta mayor grado de ausentismo. Sin embargo, fueron muy escasos los textos que exponen las cusas asociadas al ausentismo que no están relacionadas con enfermedades. Una vez finalizado el análisis de los resultados presentados por los diferentes autores consultados, podemos comprender la relación que existe entre el ausentismo y la productividad en las organizaciones, la importancia de la mejora continua en los procesos laborales y el buen manejo del clima laboral, los cuales están directamente relacionados con los empleados como foco principal de dichos estudios. Es importante mencionar que cada día de ausentismo de un colaborador representa altos costos a la organización es por esta razón que se recomienda implementar programas de salud y seguridad en el trabajo, que ayuden a minimizar riesgos y a mejorar la calidad de vida de los empleados