1,461 research outputs found
Pure Spinor Integration from the Collating Formula
We use the technique developed by Becchi and Imbimbo to construct a
well-defined BRST-invariant path integral formulation of pure spinor
amplitudes. The space of pure spinors can be viewed from the algebraic geometry
point of view as a collection of open sets where the constraints can be solved
and a free independent set of variables can be defined. On the intersections of
those open sets, the functional measure jumps and one has to add boundary terms
to construct a well-defined path integral. The result is the definition of the
pure spinor integration measure constructed in term of differential forms on
each single patch.Comment: 22 page
Impact of the covid-19 pandemic on teacher quality of life: A longitudinal study from before and during the health crisis
Background: Prior to the COVID-19 pandemic, teachers were already reporting a low quality of life (QoL) perception, with a significant impact on mental and physical health due to various stress factors associated with work overload. The objective of this study was to evaluate the QoL impact on Chilean teachers before and during the COVID-19 pandemic. The analysis was performed following a longitudinal design on a sample of 63 Chilean teachers in pre-pandemic and COVID-19 pandemic timeframes. QoL perception, along with teachers’ sociodemographic data, was evaluated via the Short-Form 36 Health Survey (SF-36) questionnaire. Sociodemographic variables presented no significant variations in pre-pandemic and pandemic comparisons. QoL, however, showed a significant decrease during the pandemic compared to the pre-pandemic measurement (p < 0.01). In each gender, there were significant differences between pre-pandemic and pandemic timeframes, with a greater impact among women in the mental and physical component summary variables and seven of the eight QoL scales (p < 0.01). Between age categories, people under 45 presented significant differences (p < 0.05) between pre-pandemic and pandemic timeframes in all summary dimensions and measurements. In conclusion, Chilean teachers’ QoL perception has been affected by the COVID-19 pandemic. These findings could be related to work overload due to teleworking or feelings of uncertainty, loneliness, and fear that the pandemic and its associated confinements will worsen
Tools to support the self assessment of the performance of Food Safety Management Systems
Changes in food supply chains, health and demographic situations, lifestyle and social situations, environmental conditions, and increased legislative requirements have led to significant efforts in the development of quality and safety management systems in agribusiness and food industry worldwide (Ropkins and Beck, 2000; Efstratiadis, Karirti, and Arvanitoyannis, 2000; Jacxsens, et al, 2009a, Luning and Marcelis, 2009a). Nowadays, companies have implemented various quality assurance (QA) guidelines and standards, such as GMP and HACCP guidelines (like General Principles of food hygiene (Codex Alimentarius 2003), GFSI guidance document (GFSI (2007), and quality assurance standards (like ISO 9001:2008 (2008), ISO22000:2005 (2005), BRC (2008), and IFS (2007) into their company own food safety management system. The performance of such systems in practice is, however, still variable. Moreover, the continuous pressure on food safety management system (FSMS) performance and the dynamic environment wherein the systems operate (such as emerging pathogens, changing consumer demands, developments in preservation techniques) require that they can be systematically analysed to determine opportunities for improvement (Wallace, et al, 2005; Manning et al, 2006; Van der Spiegel et al, 2006; Cornier et al, 2007; Luning et al, 2009a). Within the European project entitled ‘PathogenCombat- EU FOOD-CT-2005-007081’ various tools have been developed to support food companies and establishments in systematically analysing and judging their food safety management system and its microbiological performance as basis for strategic choices on interventions to improve the FSMS performance. This chapter describes briefly principles of the major tools that have been developed and some others, which are still under still under construction
Combined effect of salinity and led lights on the yield and quality of purslane (Portulaca oleracea l.) microgreens
The present work aims to explore the potential to improve quality of purslane microgreens by combining water salinity and LED lighting during their cultivation. Purslane plants were grown in a growth chamber with light insulated compartments, under different lighting sources on a 16 h d-1 photoperiod\u2014fluorescent lamps (FL) and two LED treatments, including a red and blue (RB)) spectrum and a red, blue and far red (RB+IR) LED lights spectrum\u2014while providing all of them a light intensity of 150 umol m-2 s-1. Plants were exposed to two salinity treatments, by adding 0 or 80 mM NaCl. Biomass, cation and anions, total phenolics (TPC) and flavonoids content (TFC), total antioxidant capacity (TAC), total chlorophylls (Chl) and carotenoids content (Car) and fatty acids were determined. The results showed that yield was increased by 21% both in RB and RB+FR lights compared to FL and in salinity compared to non-salinity conditions. The nitrate content was reduced by 81% and 91% when microgreens were grown under RB and RB+FR, respectively, as compared to FL light, and by 9.5% under saline conditions as compared with non-salinity conditions. The lowest oxalate contents were obtained with the combinations of RB or RB+FR lighting and salinity. The content of Cl and Na in the leaves were also reduced when microgreens were grown under RB and RB+FR lights under saline conditions. Microgreens grown under RB light reached the highest TPC, while salinity reduced TFC, Chl and Car. Finally, the fatty acid content was not affected by light or salinity, but these factors slightly influenced their composition. It is concluded that the use of RB and RB+FR lights in saline conditions is of potential use in purslane microgreens production, since it improves the yield and quality of the product, reducing the content of anti-nutritional compounds
Enhanced Fusion-Evaporation Cross Sections in Neutron-Rich Sn on Ni
Evaporation residue cross sections have been measured with neutron-rich
radioactive Sn beams on Ni in the vicinity of the Coulomb
barrier. The average beam intensity was particles per second
and the smallest cross section measured was less than 5 mb. Large subbarrier
fusion enhancement was observed. Coupled-channels calculations taking into
account inelastic excitation and neutron transfer underpredict the measured
cross sections below the barrier.Comment: 4 pages including 1 table and 3 figure
RIAM-VASP module relays integrin complement receptors in outside-in signaling driving particle engulfment
The phagocytic integrins and complement receptors M 2/CR3 and X 2/CR4 are classically
associated with the phagocytosis of iC3b-opsonized particles. The activation of this receptor is
dependent on signals derived from other receptors (inside-out signaling) with the crucial involvement
of the Rap1-RIAM-Talin-1 pathway. Here, we analyze the implication of RIAM and its binding
partner VASP in the signaling events occurring downstream of 2 integrins (outside-in) during
complement-mediated phagocytosis. To this end, we used HL-60 promyelocytic cell lines deficient in
RIAM or VASP or overexpressing EGFP-tagged VASP to determine VASP dynamics at phagocytic
cups. Our results indicate that RIAM-deficient HL-60 cells presented impaired particle internalization
and altered integrin downstream signaling during complement-dependent phagocytosis. Similarly,
VASP deficiency completely blocked phagocytosis, while VASP overexpression increased the random
movement of phagocytic particles at the cell surface, with reduced internalization. Moreover,
the recruitment of VASP to particle contact sites, amount of pSer157-VASP and formation of actin-rich
phagocytic cups were dependent on RIAM expression. Our results suggested that RIAM worked as a
relay for integrin complement receptors in outside-in signaling, coordinating integrin activation and
cytoskeletal rearrangements via its interaction with VASPThis work has been supported by Ministerio Español de Economía y Competitividad (MINECO)
grants: SAF2016-77096-R (ELD and CC), BIO2014:54164-R (PAR), BIO2017-86500-R (MY-M), EI/MICIU EXPLORA
BIO2017-91272-EXP & FEDER (PI17/02303) (S.R.-P). AT-G is supported by a predoctoral fellowship from MINECO,
JLS-T is supported by a predoctoral fellowship from Universidad Complutense de Madrid, RT-R is supported by a
postdoctoral fellowship from Asociación Española Contra el Cáncer (AECC
Characterization of oral yeasts isolated from healthy individuals attended in different Colombian dental clinics
The aim of this study was to identify the most frequent yeasts in the oral cavity of adult individuals without immune disorders and to associate the presence of these oral yeasts with different characteristics of each individual. Oral rinse samples were obtained from 96 healthy adults and cultured in Sabouraud dextrose agar media and CHROMagar. Yeasts were identified by sequencing the D1/D2 region of the 28S rRNA gene. Probable association among the socio-demographic characteristics, body mass index, family and personal medical history, oral hygiene, tobacco and/or alcohol consumption habits and presence of oral fungi was analyzed. Contingency tables and logistic regression were employed to evaluate possible relationships between the presence of oral fungi and mixed colonization with these variables. 57.3% of the healthy individuals had oral yeasts and 21.8% had mixed colonization. The most prevalent yeasts were Candida albicans (52%), C. parapsilosis (17.9%), and C. dubliniensis (7.57%). Yeasts with most frequently mixed colonization were C. albicans and C. parapsilosis. No relationships were found among the variables analyzed. However, the presence of mixed colonization was related to the presence of dental prostheses (P less than 0.006), dental apparatuses (P=0.016) and O'Leary index (P=0.012). This is the first study that characterized oral yeasts in Colombian healthy individuals, determined the most prevalent oral yeasts C. albicans, C. parapsilosis and C. dublinensis and an association of mixed colonization with the use of dental prostheses and aparatology and poor hygiene. © 2019 by the Journal of Biomedical Research
Номінація частин руки в говірці села Невгоди Овруцького району Житомирської області
У статті розглянуто лексеми на позначення частин руки в сучасній середньополіській говірці, зокрема проаналізовано їхню семантику та мотивацію.В статье рассматриваются лексемы, обозначающие части руки, в современном среднеполесском говоре, а именно проанализирована их семантика и мотивация.The article deals with lexemes on designations of parts of the manuscript in the middle-polissya dialect. Their semantics and motivation are also analyzed
Reaction and Axial Vector Coupling
The reaction is studied in the region of low
to investigate the effect of deuteron structure and width of the
resonance on the differential cross section. The results are used to extract
the axial vector coupling from the experimental data on
this reaction. The possibility to determine this coupling from electroweak
interaction experiments with high intensity electron accelerators is discussed.Comment: 14 pages, REVTEX, 5 figure
Breakup of F on Pb near the Coulomb barrier
Angular distributions of oxygen produced in the breakup of F incident
on a Pb target have been measured around the grazing angle at beam
energies of 98 and 120 MeV. The data are dominated by the proton stripping
mechanism and are well reproduced by dynamical calculations. The measured
breakup cross section is approximately a factor of 3 less than that of fusion
at 98 MeV. The influence of breakup on fusion is discussed.Comment: 7 pages, 8 figure
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