On the Nonrelativistic Limit of the phi^4 Theory in 2+1 Dimensions

We study the nonrelativistic limit of the quantum theory of a real scalar field with quartic self-interaction. The two body scattering amplitude is written in such way as to separate the contributions of high and low energy intermediary states. From this result and the two loop computation of the self energy correction, we determine an effective nonrelativistic action.Comment: 15 pages, 2 figures, revte

On the long-term correlation between the flux in the Ca II H & K and Halpha lines for FGK stars

The re-emission in the cores of the Ca II H & K and H$\alpha$ lines, are well known proxies of stellar activity. However, these activity indices probe different activity phenomena, the first being more sensitive to plage variation, while the other one being more sensitive to filaments. In this paper we study the long-term correlation between $\log R'_{HK}$ and $\log I_{H\alpha}$, two indices based on the Ca II H & K and H$\alpha$ lines respectively, for a sample of 271 FGK stars using measurements obtained over a $\sim$9 year time span. Because stellar activity is one of the main obstacles to the detection of low-mass and long-period planets, understanding further this activity index correlation can give us some hints about the optimal target to focus on, and ways to correct for these activity effects. We found a great variety of long-term correlations between $\log R'_{HK}$ and $\log I_{H\alpha}$. Around 20% of our sample has strong positive correlation between the indices while about 3% show strong negative correlation. These fractions are compatible with those found for the case of early-M dwarfs. Stars exhibiting a positive correlation have a tendency to be more active when compared to the median of the sample, while stars showing a negative correlation are more present among higher metallicity stars. There is also a tendency for the positively correlated stars to be more present among the coolest stars, a result which is probably due to the activity level effect on the correlation. Activity level and metallicity seem therefore to be playing a role on the correlation between $\log R'_{HK}$ and $\log I_{H\alpha}$. Possible explanations based on the influence of filaments for the diversity in the correlations between these indices are discussed in this paper.Comment: 18 pages, 13 figures, 4 tables, accepted for publication in Astronomy and Astrophysic

Recomendações técnicas para o processamento de conservas de cogumelos comestíveis.

Conservas de cogumelos: conservas de cogumelos esterilizados; conservas de cogumelos pasteurizados.bitstream/item/34412/1/2000-DOC-0043.pd

Competição de variedades e híbridos de sorgo forrageiro (Sorghum vulgare Pers).

bitstream/item/126643/1/Competicao-de-variedades-e-hibridos-de-sorgo-e-forrageiro.pd

The role of dogs in the relationship between telework and performance via affect: A moderated moderated mediation analysis

Although there is evidence that pets may help individuals facing significant daily stressors, and that they may enhance the well-being of their owners, little is known about the benefits of pets for job performance. Since the COVID-19 pandemic crisis, teleworking was a strategy implemented in many countries to reduce the virus widespread and to assure organizational productivity. Those who work from home and who own pets may work close to them. Based on the conservation of resources theory, this study aimed to analyze whether positive affect mediated the relationship between telecommuting and self-reported job performance and if psychological and physical closeness to the pet would moderate this relationship in such a way that it would be stronger for those who worked closer to their pet, and who were more emotionally attached to them. For this study, we collected data from 81 teleworkers who did not own pets, and from 320 teleworkers who owned pets. Both answered an online questionnaire. Findings: Results from the study showed the existence of significant differences between those who owned and who did not own pets regarding positive affect and performance, in which those who owned pets reported higher levels of positive affect and self-reported performance and perceived telework more positively. Moreover, positive affect mediated the relationship between telework and self-reported job performance. Furthermore, emotional and physical closeness moderated the mediating effect. This study contributes to a better understanding of the human-animal interaction and how pets can be a personal resource able to change their owners’ affective experiences and job performance while they are working from home. The findings demonstrate that telework may be a suitable organizational strategy for pet-owners.info:eu-repo/semantics/publishedVersio

The role of satisfaction with the performance appraisal: A comparative study between the public and private sectors

Purpose – To study in Portugal (a) whether satisfaction with the performance appraisal (PA) differs depending on the sector where the workers perform their functions (private versus public), and (b) whether the relationship between workers’ perception of usefulness and accuracy of the performance appraisal process (PAP) and satisfaction with the outcome of their last PA is mediated by their satisfaction with the PAP.Theoretical framework – The PA has come to occupy a prominent place in organizations, because only it can be used to measure the skills of their workers and the way they contribute to achieving organizational success both qualitatively and quantitatively.Design/methodology/approach – Eight hundred and sixty-six professionals from the public and private sectors participated in this study. Data were collected using two multi-item questionnaires and two single-item scales.Findings – The results revealed that private sector employees showed higher levels of satisfaction with their PAs than those from the public sector. Furthermore, the results indicated that the usefulness and accuracy of the PAP had a significant and positive relationship with employees’ satisfaction with their last PA, and this relationship was partially mediated by satisfaction with the PAP, both in the public and private sectors.Practical & social implications of research – Regardless of the activity sector, it is fundamental that the PAP is useful and accurate; otherwise it is discredited, which prevents it from fulfilling its purpose and contributes to increasing the levels of worker dissatisfaction.Originality/value – This study clarified the differences that may emerge regarding satisfaction with PAs between the Portuguese public and private sectors. In addition, this is the first national or international study to analyse the aforementioned constructs in an integrated manner.info:eu-repo/semantics/publishedVersio

Pneumoperitoneum in Peritoneal Dialysis Patients

O Pneumoperitoneu no doente em diálise peritoneal é uma complicação rara, no entanto deve ser tida em atenção de forma a evitar uma laparotomia desnecessária que possa comprometer esta opção dialítica. Os autores qpresentam o cado de uma doente de 70 anos de idade com insuficiência renal crónica, em diálise peritoneal há 21 meses, sem qualquer complicação ou sinal de peritonite. Admitida no serviço de urgência com dor epigástrica súbita. À observação, um abdómen timpanizado, sem alterações na porção externa do cateter de Tenckhoff. Analiticamente sem leucocitose. O Rx Abdominal demonstrou a existência de pneumoperitoneu. A TC abdominal confirmou uma pneumoperitoneu generalizado mas predominante no andar supramesocólico, sem extravasamento de contraste oral e com o cateter de diálise bem posicionado no quadrante inferior esquerdo. Procedeu-se à aspiração do pneumoperitoneu através de um técnica asséptica em posição de Trendlenburg, com confirmação radiológica da resolução do mesmo. Constatou-se recorrência do penumoperitoneu no dia seguinte, apesar da doente permanecer assintomática, pelo que se procedeu à remoção do cateter, sem recorrência do pneumoperitoneu.info:eu-repo/semantics/publishedVersio

Antimicrobial peptides as potential anti-tubercular leads: A concise review

Despite being considered a public health emergency for the last 25 years, tuberculosis (TB) is still one of the deadliest infectious diseases, responsible for over a million deaths every year. The length and toxicity of available treatments and the increasing emergence of multidrugresistant strains of Mycobacterium tuberculosis renders standard regimens increasingly inefficient and emphasizes the urgency to develop new approaches that are not only cost-and time-effective but also less toxic. Antimicrobial peptides (AMP) are small cationic and amphipathic molecules that play a vital role in the host immune system by acting as a first barrier against invading pathogens. The broad spectrum of properties that peptides possess make them one of the best possible alternatives for a new “post-antibiotic” era. In this context, research into AMP as potential anti-tubercular agents has been driven by the increasing danger revolving around the emergence of extremely-resistant strains, the innate resistance that mycobacteria possess and the low compliance of patients towards the toxic anti-TB treatments. In this review, we will focus on AMP from various sources, such as animal, non-animal and synthetic, with reported inhibitory activity towards Mycobacterium tuberculosis.This research was funded by Fundação para a Ciência e Tecnologia (FCT), Portugal, through projects UIDB/50006/2020, and PTDC/BTM-SAL/29786/2017

Microbial lipids and added value metabolites production by Yarrowia lipolytica from pork lard

Yarrowia lipolytica is a suitable microbial platform to convert low-value hydrophobic substrates into microbial oils and other important metabolites. In this work, this yeast species was used to simultaneously synthetize ex novo lipids and produce citric acid and lipase from animal fat (pork lard) adding higher value to the low-cost fatty substrate. The effect of pH, lard concentration, arabic gum concentration and oxygen mass transfer rate (OTR) on lipids accumulation on Y. lipolytica batch cultures was assessed by an experimental design based on Taguchi method. OTR was by far the most influential parameter in the range of 96 mg L1 h1 to 480 mg L1 h1. A bio-modification of initial lipidic substrate was observed and, depending on the nutritional and operational conditions, specialty lipids with specific composition and high added-value were obtained. The unsaturated-to-saturated fatty acids ratio of these microbial lipids is higher than in initial substrate, which indicates that they are more suitable than animal fat for food additives. Moreover, the simultaneous induction of lipase and citric acid by Y. lipolytica growing in animal fat demonstrate that a biorefinery approach may be designed based on animal fat raw material.This work was financially supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the project TÜBITAK 2014 (TUBITAK/0009/2014) and of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145FEDER-006684), Post-Doctoral grant (SFRH/BPD/101034/2014) attributed to Marlene Lopes and BioTecNorte operation (NORTE-010145-FEDER-000004) funded by European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio