2,067 research outputs found

    The Relation between Radio Polarization and Gamma-ray Emission in AGN Jets

    Full text link
    We have compared the parsec-scale jet linear polarization properties of the Fermi LAT-detected and non-detected sources in the complete flux-density-limited (MOJAVE-1) sample of highly beamed AGN. Of the 123 MOJAVE sources, 30 were detected by the LAT during its first three months of operation. We find that during the era since the launch of Fermi, the unresolved core components of the LAT-detected jets have significantly higher median fractional polarization at 15 GHz. This complements our previous findings that these LAT sources have higher apparent jet speeds, brightness temperatures and Doppler factors, and are preferentially found in higher activity states.Comment: 6 pages, 3 figures, to appear in the proceedings of "High Energy Phenomena In Relativistic Outflows II" (Buenos Aires, Argentina, October 26-30, 2009) International Journal of Modern Physics

    Long-term changes in extreme temperatures and precipitation in Spain

    Get PDF
    La creació de les bases de dades de temperatura i precipitació diàries anomenades, respectivament, Spanish Daily Adjusted Temperature Series (SDATS) i Spanish Daily Adjusted Precipitation Series (SDAPS), en el marc del projecte finançat per la Comissió Europea EMULATE (European and North Atlantic daily to MULtidecadal climATE variability), ha permès als autors analitzar el canvi a llarg termini que s'ha produït en el comportament anual dels extrems climàtics a l'Espanya peninsular durant el període 1901-2005. El conjunt de procediments desenvolupats pels autors per tal de crear registres homogenis de la temperatura i de la precipitació diàries són descrits de manera breu abans d'analitzar els canvis observats en l'ocurrència d'extrems climàtics. S'han utilitzat els indicadors se - güents per a dur a terme aquest estudi: excedències dels percentils inferiors i superiors de les temperatures màximes (Tmax) i mínimes (Tmin) diàries, excedències de la precipitació diària per sobre dels percentils 95è i 99è, l'índex simple d'intensitat diària (SDII) i els indicadors d'1 i 5 dies amb la precipitació més alta de l'any. Tant l'anàlisi dels percentils superiors de les temperatures com la dels inferiors mostren que s'ha produït un escalfament important sobre l'Espanya peninsular al llarg del segle XX, i que aquest ha estat més important en les temperatures màximes que en les temperatures mínimes. No obstant això, aquest patró presenta un lleuger canvi en el període més recent d'escalfament, en el qual la tendència d'ambdues variables presenta valors similars. Els canvis en els indicadors pluviomètrics no són tan clars com els estimats per la temperatura, però s'ha detectat una tendència cap a l'ocurrència de pluges més intenses.The development of the Spanish daily adjusted temperature series (SDATS) and the Spanish daily adjusted precipitation series (SDAPS) datasets in the framework of the European Community (EC)-funded project EMULATE (European and North Atlantic daily to MULtidecadal climATE variability) enabled the assessment of long-term annual changes of extreme temperature and precipitation indices over peninsular Spain for the period 1901–2005. Within this framework, a set of procedures was developed to generate long-term (1850–2005) daily adjusted temperature and precipitation series and to use them to assess changes in climatic extremes. The present report describes details of the data employed to analyze the behavior of Spanish climate extremes and discusses the results of investigations into the annual changes in selected indices that occurred during the 20th century: exceedances of upper and lower percentiles of daily maximum (Tmax) and minimum (Tmin) temperatures, cold-spell duration index (CSDI), warm-spell duration index (WSDI), daily rainfall (R) exceeding the 95th and 99th percentiles, simple daily intensity index (SDII), and greatest 1- and 5-day total precipitation. Upper and lower temperature percentiles increased during the 20th century over mainland Spain, but changes in daytime extreme temperatures were larger than changes in night-time extreme temperatures. This pattern, however, shifted slightly in the recent period of strong warming, with more similar rates of change among daytime and night-time extreme temperatures. Changes in extreme precipitation indices were not as evident as those in extremetemperature indices, but there was a tendency towards heavier precipitation

    Genotype and environment affect the grain quality and yield of winter oats (Avena sativa L.)

    Get PDF
    The extent to which the quality and yield of plant varieties are influenced by the environment is important for their successful uptake by end users particularly as climatic fluctuations are resulting in environments that are highly variable from one growing season to another. The genotype-by-environment interaction (GEI) of milling quality and yield was studied using four winter oat varieties in multi-locational trials over 4 years in the U.K. Significant differences across the 22 environments were found between physical grain quality and composition as well as grain yield, with the environment having a significant effect on all of the traits measured. Grain yield was closely related to grain number m−2 whereas milling quality traits were related to grain size attributes. Considerable genotype by environment interaction was obtained for all grain quality traits and stability analysis revealed that the variety Mascani was the least sensitive to the environment for all milling quality traits measured whereas the variety Balado was the most sensitive. Examination of environmental conditions at specific within-year stages of crop development indicated that both temperature and rainfall during grain development were correlated with grain yield and β-glucan content and with the ease of removing the hull (hullability)

    A new daily observational record from Grytviken, South Georgia: exploring 20th century extremes in the South Atlantic

    Get PDF
    Although recent work has highlighted a host of significant late 20th century environmental changes across the mid to high latitudes of the Southern Hemisphere, the sparse nature of observational records limits our ability to place these changes in the context of long-term (multi-decadal and centennial) variability. Historical records from sub-Antarctic islands offer considerable potential for developing highly resolved records of change. In 1905, a whaling and meteorological station was established at Grytviken on sub-Antarctic South Georgia in the South Atlantic (54°S, 36°W) providing near-continuous daily observations through to present day. Here we report a new, daily observational record of temperature and precipitation from Grytviken, which we compare to regional datasets and historical reanalysis (Twentieth Century Reanalysis; 20CR version 2c). We find a shift towards increasingly warmer daytime extremes commencing from the mid-20th century and accompanied by warmer night-time temperatures, with an average rate of temperature rise of 0.13°C per decade over the period 1907-2016 (p<0.0001). Analysis of these data, and reanalysis products, suggest a change of particular synoptic conditions across the mid to high-latitudes since the mid-20th century, characterised by stronger westerly airflow and associated warm föhn winds across South Georgia. This rapid rate of warming and associated declining habitat suitability has substantial negative implications for biodiversity levels and survival of key marine biota in the region

    Effectiveness Test on Centella asiatica Extract on Increasing Elasticity Level on Male Mus Musculus

    Get PDF
    Gotu kola (Centella asiatica), is one of the plants with a potential development in dermatocosmetology, because it contains triterpenoid compounds, asiaticoside, madecassoside, flavonoids, efficacious as an antioxidant and prevent skin premature aging. The aim of this study was to compare the effectiveness of anti-aging extract of Centella asiatica to increase elasticity levels. Phytochemical test results of extracts contain alkaloids, tannins, triterpenoid, flavonoids, glycosides. The results showed that the research data were abnormally distributed (p &lt;0.05), the average highest measurement of skin elasticity levels was found in the 10% extraction treatment group. The difference in the average measurement of significant elasticity levels at weeks 2, 3, and 4 were p &lt;0.005 (p0,045; p0,008; p0,009). The difference in average elasticity level will increase significantly (p &lt;0.005) in line with the length of time spent. Cream with 10% of Centella asiatica&nbsp; extract showed an increase in skin elasticity levels by 40.58%. The multiple linear regression test, the greatest Pearson correlation value at week 4 on all measurements was found in comparison with week 3, elasticity levels (94.2% p0,000) and the results of the correlation value increased significantly with the addition of treatment time (p &lt;0.005). In conclusion, the results of this study indicate the administration of Centella asiatica extract increased the average of elasticity level compared to the control group, positively correlated with the increase of the duration and the quantity of Centella asiatica extract were given

    Identification of Extracellular DNA-Binding Proteins in the Biofilm Matrix.

    Get PDF
    We developed a new approach that couples Southwestern blotting and mass spectrometry to discover proteins that bind extracellular DNA (eDNA) in bacterial biofilms. Using Staphylococcus aureus as a model pathogen, we identified proteins with known DNA-binding activity and uncovered a series of lipoproteins with previously unrecognized DNA-binding activity. We demonstrated that expression of these lipoproteins results in an eDNA-dependent biofilm enhancement. Additionally, we found that while deletion of lipoproteins had a minimal impact on biofilm accumulation, these lipoprotein mutations increased biofilm porosity, suggesting that lipoproteins and their associated interactions contribute to biofilm structure. For one of the lipoproteins, SaeP, we showed that the biofilm phenotype requires the lipoprotein to be anchored to the outside of the cellular membrane, and we further showed that increased SaeP expression correlates with more retention of high-molecular-weight DNA on the bacterial cell surface. SaeP is a known auxiliary protein of the SaeRS system, and we also demonstrated that the levels of SaeP correlate with nuclease production, which can further impact biofilm development. It has been reported that S. aureus biofilms are stabilized by positively charged cytoplasmic proteins that are released into the extracellular environment, where they make favorable electrostatic interactions with the negatively charged cell surface and eDNA. In this work we extend this electrostatic net model to include secreted eDNA-binding proteins and membrane-attached lipoproteins that can function as anchor points between eDNA in the biofilm matrix and the bacterial cell surface.IMPORTANCE Many bacteria are capable of forming biofilms encased in a matrix of self-produced extracellular polymeric substances (EPS) that protects them from chemotherapies and the host defenses. As a result of these inherent resistance mechanisms, bacterial biofilms are extremely difficult to eradicate and are associated with chronic wounds, orthopedic and surgical wound infections, and invasive infections, such as infective endocarditis and osteomyelitis. It is therefore important to understand the nature of the interactions between the bacterial cell surface and EPS that stabilize biofilms. Extracellular DNA (eDNA) has been recognized as an EPS constituent for many bacterial species and has been shown to be important in promoting biofilm formation. Using Staphylococcus aureus biofilms, we show that membrane-attached lipoproteins can interact with the eDNA in the biofilm matrix and promote biofilm formation, which suggests that lipoproteins are potential targets for novel therapies aimed at disrupting bacterial biofilms

    Comparison of sequencing-based methods to profile DNA methylation and identification of monoallelic epigenetic modifications.

    Get PDF
    Analysis of DNA methylation patterns relies increasingly on sequencing-based profiling methods. The four most frequently used sequencing-based technologies are the bisulfite-based methods MethylC-seq and reduced representation bisulfite sequencing (RRBS), and the enrichment-based techniques methylated DNA immunoprecipitation sequencing (MeDIP-seq) and methylated DNA binding domain sequencing (MBD-seq). We applied all four methods to biological replicates of human embryonic stem cells to assess their genome-wide CpG coverage, resolution, cost, concordance and the influence of CpG density and genomic context. The methylation levels assessed by the two bisulfite methods were concordant (their difference did not exceed a given threshold) for 82% for CpGs and 99% of the non-CpG cytosines. Using binary methylation calls, the two enrichment methods were 99% concordant and regions assessed by all four methods were 97% concordant. We combined MeDIP-seq with methylation-sensitive restriction enzyme (MRE-seq) sequencing for comprehensive methylome coverage at lower cost. This, along with RNA-seq and ChIP-seq of the ES cells enabled us to detect regions with allele-specific epigenetic states, identifying most known imprinted regions and new loci with monoallelic epigenetic marks and monoallelic expression

    Measuring the jet power of flat spectrum radio quasars

    Full text link
    We use frequency-dependent position shifts of flat spectrum radio cores to estimate the kinetic power of AGN jets. We find a correlation between the derived jet powers and AGN narrow-line luminosity, consistent with the well-known relation for radio galaxies and steep spectrum quasars. This technique can be applied to intrinsically weak jets even at high redshift.Comment: 6 pages, 3 figures. ApJ in pres
    • …
    corecore