A study of the elements copper through uranium in Sirius A: Contributions from STIS and ground-based spectra

We determine abundances or upper limits for all of the 55 stable elements from copper to uranium for the A1 Vm star Sirius. The purpose of the study is to assemble the most complete picture of elemental abundances with the hope of revealing the chemical history of the brightest star in the sky, apart from the Sun. We also explore the relationship of this hot metallic-line (Am) star to its cooler congeners, as well as the hotter, weakly- or non-magnetic mercury-manganese (HgMn) stars. Our primary observational material consists of {\em Hubble Space Telescope} ($HST$) spectra taken with the Space Telescope Imaging Spectrograph (STIS) in the ASTRAL project. We have also used archival material from the %\citep/{ayr10}. $COPERNICUS$ satellite, and from the $HST$ Goddard High-Resolution Spectrograph (GHRS), as well as ground-based spectra from Furenlid, Westin, Kurucz, Wahlgren, and their coworkers, ESO spectra from the UVESPOP project, and NARVAL spectra retrieved from PolarBase. Our analysis has been primarily by spectral synthesis, and in this work we have had the great advantage of extensive atomic data unavailable to earlier workers. We find most abundances as well as upper limits range from 10 to 100 times above solar values. We see no indication of the huge abundance excesses of 1000 or more that occur among many chemically peculiar (CP) stars of the upper main sequence. The picture of Sirius as a hot Am star is reinforced.Comment: With 6 Figures and 4 Tables; accepted for publication in Ap

Functional metathesis catalyst through ring closing enyne metathesis: one pot protocol for living heterotelechelic polymers

Enyne ring closing metathesis has been used to synthesize functional group carrying metathesis catalysts from a commercial (Ru-benzylidene) Grubbs’ catalysts. The new Grubbs-type ruthenium carbene was used to synthesize living heterotelechelic ROMP polymers without any intermediate purification. Olefin metathesis with a mono substituted alkyne followed by ring closing metathesis with an allylic ether provided efficient access to new functional group carrying metathesis catalysts. Different functional benzylidene and alkylidene derivatives have been investigated in the synthesis of heterotelechelic polymers in one pot

Polarizations and differential calculus in affine spaces

Within the framework of mappings between affine spaces, the notion of $n$-th polarization of a function will lead to an intrinsic characterization of polynomial functions. We prove that the characteristic features of derivations, such as linearity, iterability, Leibniz and chain rules, are shared -- at the finite level -- by the polarization operators. We give these results by means of explicit general formulae, which are valid at any order $n$, and are based on combinatorial identities. The infinitesimal limits of the $n$-th polarizations of a function will yield its $n$-th derivatives (without resorting to the usual recursive definition), and the above mentioned properties will be recovered directly in the limit. Polynomial functions will allow us to produce a coordinate free version of Taylor's formula

Genetic tools discriminate strains of leishmania infantum isolated from humans and dogs in Sicily, Italy

Background Leishmaniasis is one of the most important vector-borne diseases and it represents a seri-ous world health problem affecting millions of people. High levels of Leishmania infections, affecting both humans and animals, are recognized among Italian regions. Among these, Sicily has one of the highest prevalence of Leishmania infection. Methodology/Principal Findings Seventy-eight Leishmania strains isolated from human and animal samples across Sicily, were analyzed for the polymorphic k26-gene and genotypes were assigned according to the size of the PCR products. A multilocus microsatellite typing (MLMT) approach based on the analysis of 11 independent loci was used to investigate populations structure and genetic diversity of the isolated strains. Six L. infantum reference strains were included in the analysis for comparison. Bayesian clustering analysis of microsatellite data showed that all the isolated strains clustered in two genetically distinct populations, corresponding to human and canine isolates respectively. A further subdivision was observed between the two main groups, giving a good correlation between human strains and their geographic origin, conversely canine population showed a great genetic variability diffused in the territory. Conclusions/Significance Among the 78 Leishmania isolates, K26 analysis detected 71 samples (91%) as MON-1 zymodeme, confirming it as the predominant strain in Mediterranean area and 7 human samples (9%) as non-MON-1. MLMT gives important insights into the epidemiology of leish-maniases and allows characterization of different strains to a higher resolution than possible with zymodeme typing. Two main populations presented a strong correlation respect to the different hosts, exhibiting a co-circulation of two distinct populations of L. infantum. The population found in infected humans exhibited a correlation with geographic origin. These clusters could represent a geographically restricted population of strains with the same or related genotypes. This study can contribute to an understanding of Leishmania epidemiol-ogy, including the spread of reservoirs and sand fly vectors in the different foci of infection, characterizing parasites within the different hosts

The impact of COVID-19 on diet quality, food security and nutrition in low and middle income countries: a systematic review of the evidence

Background & Aims: The current global pandemic of Coronavirus (COVID-19), and measures adopted to reduce its spread, threaten the nutritional status of populations in Low- and middle-income countries (LMICs). Documenting how the COVID-19 affects diets, nutrition and food security can help generating evidence-informed recommendations for mitigating interventions and policies. Methods: We carried out a systematic literature review. A structure search strategy was applied in MEDLINE (Pubmed®), EMBASE®, Scopus® and Web of Science®. Grey literature was retrieved by screening a pre-set list of institutions involved in monitoring the impact of COVID-19 pandemic on nutrition and food security. The first search was done on 20th August 2020, and updated in mid-November 2020 and mid-January 2021. All research steps were described as recommended in the PRISMA statement. Results: Out of the 2085 references identified, thirty-five primary studies were included. In spite of their heterogeneity, studies converge to demonstrate a detrimental effect of COVID-19 pandemic and associated containment measures on diet quality and food insecurity. One of the major direct effects of COVID-19 on food and nutrition outcomes has been through its impact on employment, income generating activities and associated purchasing power. Other channels of impact, such as physical access, availability and affordability of food provided a heterogeneous picture and were assessed via binary and often simplistic questions. The impacts of COVID-19 manifested with various intensity degrees, duration and in different forms. Factors contributing to these variations between and within countries were: 1) timing, duration and stringency of national COVID-19 restriction measures and policies to mitigate their adverse impacts; 2) context specific food value chain responses to domestic and international containment measures; 3) differentiated impacts of restriction measures on different groups, along lines of gender, age, socio-economic status and employment conditions. Dietary changes and food insecurity manifested various intensity degrees, duration and in different forms between and within countries. Shorter value chains and traditional smallholder farms were somewhat more resilient in the face of COVID-19 pandemic. Additionally, the impact of the pandemic has been particularly adverse on women, individuals with a low socio-economic status, informal workers and young adults that relied on daily wages. Finally, there were heterogeneous government responses to curb the virus and to mitigate the damaging effects of the pandemic. It has been demonstrated that existing and well-functioning social protection programmes and public distribution of food can buffer the adverse effects on food insecurity. But social safety nets cannot be effective on their own and there is a need for broader food systems interventions and investments to support sustainable and inclusive food systems to holistic achieve food and nutrition security. Conclusion: In conclusion, the current economic and heath crisis impact diet quality and food security, and this raises concerns about long term impacts on access to and affordability of nutrient-rich, healthy diets and their health implications. Women and individuals with a low socio-economic are the most at risk of food insecurity. Social safety nets can be effective to protect them and must be urgently implemented. We advocate for improved data collection to identify vulnerable groups and measure how interventions are successful in protecting them

El Estado contra el Estado: el modelo peruano de eliminación de barreras burocráticas como propuesta para el crecimiento económico de países en vías de desarrollo

In this paper, the authors describe the Peruvian model for removing of bureaucratic barriers and argue that this has become a positive practice for internal control -from and to - the administration itself against bureaucratic obstacles affecting the growth of a country. They understand that this model can serve to encourage other developing countries to have a debate about the need to seek mechanisms that support investment and legal economic stability.En el presente artículo los autores describen el modelo peruano de eliminación de barreras burocráticas y consideran que este se ha convertido en un ejercicio positivo de control interno desde y hacia la propia Administración frente a trabas burocráticas que afectan el crecimiento de un país. Entienden que este modelo puede servir de impulso a otros países en vías de desarrollo para plantear la discusión acerca de la necesidad de buscar mecanismos que incentiven la inversión y la estabilidad económica y legal