640 research outputs found
Oblique surface waves at an interface of metal-dielectric superlattice and isotropic dielectric
We investigate the existence and the dispersion characteristics of surface
waves that propagate at an interface between metal-dielectric superlattice and
isotropic dielectric. Within the long wavelength limit, when the
effective-medium approximation is valid, the superlattice behaves like a
uniaxial plasmonic crystal with the main optical axes perpendicular to the
metal-dielectric interfaces. We demonstrate that if such a semi-infinite
plasmonic crystal is cut normally to the layer interfaces and brought into the
contact with semi-infinite dielectric, a new type of surface modes can appear.
The propagation of such modes obliquely to the optical axes occurs under
favorable conditions that regard thicknesses of the layers, as well as the
proper choice of dielectric permittivity of the constituent materials. We show
that losses within the metallic layers can be substantially reduced by making
the layers sufficiently thin. At the same time, a dramatic enlargement of the
range of angles for oblique propagation of the new surface modes is observed.
This can lead, however, to the field non-locality and consequently to the
failure of the effective-medium approximation.Comment: 4 pages, 3 figure
High-throughput Quantum Chemistry: Empowering the Search for Molecular Candidates behind Unknown Spectral Signatures in Exoplanetary Atmospheres
The identification of molecules in exoplanetary atmospheres is only possible
thanks to the availability of high-resolution molecular spectroscopic data.
However, due to its intensive and time-consuming generation process, at
present, only on order 100 molecules have high-resolution spectroscopic data
available, limiting new molecular detections.
Using routine quantum chemistry calculations (i.e., scaled harmonic frequency
calculations using the B97-1/def2-TZVPD model chemistry with median errors of
10cm-1), here we present a complementary high-throughput approach to rapidly
generate approximate vibrational spectral data for 2743 molecules made from the
biologically most important elements C, H, N, O, P and S. Though these data are
not accurate enough to enable definitive molecular detections and does not seek
to replace the need for high-resolution data, it has powerful applications in
identifying potential molecular candidates responsible for unknown spectral
features. We explore this application for the 4.1 micron (2439cm-1) feature in
the atmospheric spectrum of WASP-39b, listing potential alternative molecular
species responsible for this spectral line, together with SO2. Further
applications of this big data compilation also include identifying molecules
with strong absorption features that are likely detectable at quite low
abundances, and training set for machine learning predictions of vibrational
frequencies.
Characterising exoplanetary atmospheres through molecular spectroscopy is
essential to understand the planet's physico-chemical processes and likelihood
of hosting life. Our rapidly generated quantum chemistry big data set will play
a crucial role in supporting this understanding by giving directions into
possible initial identifications of the more unusual molecules to emerge
Synthesis, In Silico Studies, Antiprotozoal and Cytotoxic Activities of Quinoline‐Biphenyl Hybrids
This is the pre-peer reviewed version of the following article: Synthesis, In Silico Studies, Antiprotozoal and Cytotoxic Activities of Quinoline‐Biphenyl Hybrids, which has been published in final form at https://doi.org/10.1002/slct.201903835. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsThe synthesis, in silico studies, antiprotozoal and cytotoxic activities of eleven quinoline‐biphenyl hybrids are described herein. The structure of the synthesized products was elucidated by a combination of spectrometric analyses. The synthesized compounds were evaluated against Plasmodium falciparum, and amastigotes forms both Leishmania (V) panamensis and Trypanosoma cruzi. Cytotoxicity was evaluated against human U‐937 macrophages. 8‐phenylquinoline (4 a) showed similar activity than meglumine antimoniate and 4‐(quinolin‐8‐yl)phenol (4 b) exhibited an activity similar to that of benznidazole. 8‐(3,4‐dimethoxyphenyl) quinoline (4 k) showed the best activity against P. falciparum. Although these compounds were toxic for mammalian U‐937 cells, however they may still have potential to be considered as candidates for drug development because of their antiparasite activity. Molecular docking was used to determine the in silico inhibition of some of the designed compounds against PfLDH and cruzipain, two important pharmacological targets involved in antiparasitic diseases. All hybrids were docked to the three‐dimensional structures of PfLDH and T. cruzi cruzipain as enzymes using AutoDock Vina. Notably, the docking results showed that the most active compounds 4‐(quinolin‐8‐yl)phenol (4 b, CE50: 11.33 μg/mL for T. cruzi) and 8‐(3,4‐dimethoxyphenyl) quinoline (4 k, CE50: 8.84 μg/mL for P. falciparum) exhibited the highest scoring pose (−7.5 and −7.7 kcal/mol, respectively). This result shows a good correlation between the predicted scores with the experimental data profile, suggesting that these ligands could act as competitive inhibitors of PfLDH or T. cruzi cruzipain enzymes, respectively. Finally, in silico ADME studies of the quinoline hybrids showed that these novel compounds have suitable drug‐like properties, making them potentially promising agents for antiprotozoal therapy
The Effect of Lifestyle Intervention on Pregnancy and Birth Outcomes on Obese Infertile Women : a Systematic Review and Meta-Analysis
Obesity has been associated with negative effects on natural fertility and poor prognosis when assisted reproductive technologies (ART) are performed. Patients attending for fertility treatments are often advised to optimize their weights to improve the outcomes. There is lack of enough information on how weight-loss would be effective for improving fertility in women who are overweight or obese. We conducted a systematic review to evaluate whether weight-loss achieved by lifestyle program improves natural or assisted reproduction in obese infertile women. We searched CENTRAL, MEDLINE, and EMBASE up to March 2018. Two reviews were selected as randomised trials assessing a lifestyle intervention in women with obesity before receiving treatments for infertility and appraised their risk of bias. We extracted data on pregnancy, birth, and miscarriage rates as the primary outcomes and pooled effect estimates using a random effects model. The primary outcome was the live birth rate. We reported summary measures as the relative risk (RR), 95% confidence interval (CI), and percentage of heterogeneity (I2). We included eight randomised trials with 1175 women. Lifestyle programmes, improved pregnancy rates (RR: 1.43, CI: 95% 1.02 to 2.01; I2=60%; 8 RCTs; N=1098) but had no impact on live births (RR: 1.39, CI: 95% 0.90 to 2.14; I2=64%; 7RCTs; N=1034). Our findings suggest that women participating in lifestyle interventions had an increased risk of miscarriage (RR: 1.50, CI: 95% 1.04 to 2.16; I2=0; 6RCTs; N=543). We rated the quality of evidence for these outcomes as the moderate-to-low. Lifestyle interventions slightly increased the pregnancy rate, while it would be uncertain whether it can improve the live birth. Lifestyle interventions can increase the risk of miscarriage. More research is needed to further explore lifestyle interventions on reproductive outcomes in obese infertile women. Instituto de Salud Carlos II
Scavenger guild and consumption patterns of an invasive alien fish species in a Mediterranean wetland
Invasive Alien Species (IAS) alter ecosystems, disrupting ecological processes and driving the loss of ecosystem services. The common carp Cyprinus carpio is a hazardous and widespread IAS, becoming the most abundant species in many aquatic ecosystems. This species transforms ecosystems by accumulating biomass to the detriment of other species, thus altering food webs. However, some terrestrial species, such as vertebrate scavengers, may benefit from dead carps, by incorporating part of the carp biomass into the terrestrial environment. This study describes the terrestrial vertebrate scavenger assemblage that benefits from carp carcasses in a Mediterranean wetland. We also evaluate the seasonal differences in the scavenger assemblage composition and carrion consumption patterns. Eighty carp carcasses (20 per season) were placed in El Hondo Natural Park, a seminatural mesohaline wetland in south-eastern Spain, and we monitored their consumption using camera traps. We recorded 14 scavenger species (10 birds and four mammals) consuming carp carcasses, including globally threatened species. Vertebrates consumed 73% of the carrion biomass and appeared consuming at 82% of the carcasses. Of these carcasses consumed, 75% were completely consumed and the mean consumption time of carcasses completely consumed by vertebrates was 44.4 h (SD = 42.1 h). We recorded differences in species richness, abundance, and assemblage composition among seasons, but we did not find seasonal differences in consumption patterns throughout the year. Our study recorded a rich and efficient terrestrial vertebrate scavenger assemblage benefitting from carp carcasses. We detected a seasonal replacement on the scavenger species, but a maintenance of the ecological function of carrion removal, as the most efficient carrion consumers were present throughout the year. The results highlight the importance of vertebrate scavengers in wetlands, removing possible infectious focus, and moving nutrients between aquatic and terrestrial environments.JMPG was supported by Spanish Ministry of Science, Innovation and Universities contracts (IJC-2019-038968). ESG received the grants PID 2021-124744NA-I00 and RYC2019-027216-I funded by MCIN/AEI/ https://doi.org/10.13039/501100011033 and by ESF Investing in your future
Reporte de análisis cuantitativo de datos: estudio de mercado preferencias de consumo aceite de aguacate hass
This article presents the results of the study that sought to determine the consumption preferences of Hass avocado oil in the cities of Bogotá, Tunja, Bucaramanga and Villavicencio (Colombia), it was carried out through a non-experimental exploratory cross-sectional design taking into account He says that the objective was to obtain a panoramic view of people’s interest in avocado oil products, and identify possible uses and aspects for the development of the product, for which an information collection instrument focused on the supply was designed, demand and price for Hass avocado oil, the population size of this study was 8.465.949, the sample size is 1,872. A very favorable aspect was observed at a general level, such as the great possibility of substituting the different oils that are commonly used with the use of avocado oil, for nutritional purposes (72%), pharmacological use (45%), cosmetic use (57 %) uses as a dressing (75%), in fried foods (63%) and in food cooking (78%). The price that they would be willing to pay for 100mL of avocado oil is in the range of 15.000; 98% of the respondents indicated their interest in the use of avocado oil.En el presente artículo se presenta el resultado del estudio que buscaba determinar las preferencias de consumo de aceite de aguacate Hass en las ciudad de Bogotá, Tunja, Bucaramanga y Villavicencio (Colombia), se llevó a cabo mediante un diseño transversal exploratorio no experimental teniendo en cuenta que el objetivo era obtener una visión panorámica del interés de las personas por los productos de aceite de aguacate, e identificar posibles sus usos y aspecto para el desarrollo del producto, para lo cual se diseñó un instrumento de recolección de información enfocado a la oferta, demanda y precio para el aceite de aguacate hass, el tamaño de la población de este estudio fue de 8.465.949, el tamaño de la muestra es de 1.872. Se observó a nivel general un aspecto muy favorable como lo fue la gran posibilidad de sustituir los diferentes aceites que usan habitualmente con el uso del aceite de aguacate, para fines nutricionales (72%), uso farmacológico (45%), uso cosmético (57%) uso como aderezo (75%), en frituras (63%) y en cocción de alimentos (78%). El precio que estarían dispuestos a pagar por 100mL de aceite de aguacate esta entre un rango de 15.000; el 98% de los encuestados indicaron su interés en el uso del aceite de aguacate.Este artigo apresenta os resultados do estudo que procurou determinar as preferências de consumo do óleo de abacate Hass nas cidades de Bogotá, Tunja, Bucaramanga e Villavicencio (Colômbia), foi realizado através de um desenho transversal exploratório não experimental tendo em conta que o objectivo era obter uma visão panorâmica do interesse das pessoas pelos produtos de óleo de abacate, e para identificar possíveis usos e aspectos para o desenvolvimento do produto, para o qual foi concebido um instrumento para recolher informação centrada na oferta, procura e preço do óleo de abacate, a dimensão da população deste estudo foi 8. 465.949, a dimensão da amostra é de 1.872. Observou-se um aspecto muito favorável a nível geral, como a grande possibilidade de substituir os diferentes óleos que normalmente utilizam pelo óleo de abacate, para fins nutricionais (72%), farmacológicos (45%), cosméticos (57%), como molho (75%), em frituras (63%) e na confecção de alimentos (78%). O preço que estariam dispostos a pagar por 100mL de óleo de abacate varia entre 15.000; 98% dos inquiridos indicaram interesse em utilizar óleo de abacate
Discriminant analysis using fatty acids profile, stable carbon isotopes and tocopherols content as tool for feeding system prediction in Iberian pigs
Aim of study: The application of three analytical methods (fatty acids: FA, tocopherols: TOC, and isotope ratio: ISO) to distinguish the feeding type received by Iberian pigs during the fattening stage.Area of study: This distinction is very important for the labelling of Iberian high-quality products in the Quercus forest located on the southwest of Iberian Peninsula, where several production systems coexist.Material and methods: Discriminant analysis on fat samples with unknown background obtained from commercial pigs was applied. The feasibility of the combination method to determine the authentication of feeding background was studied on samples from different fattening system: free-range feeding with acorn and pastures (BE); free-range feeding acorn and pastures plus commercial feeds (RE); open-air feeding with commercial feeds (CA); standard feeding with commercial feeds (CE).Main results: In a first application of the methods, the overall success rate was 60.1% for FA, 49.7% for ISO and 49.3% for TOC. When some of the batches were reclassified attending to those previous results and additional information available about farm characteristics, ISO and TOC analyses had a 70% of success rate in the four categories, whereas FA showed 40.5%, attributable to the use of high-oleic commercial diets. The predictions improved with the method combination. The ISO+TOC combination achieved a 84.1% of success in prediction. When it was reduced to just two categories (acorn vs non-acorn), the success reached a 95% for FA+TOC and ISO+TOC.Research highlights: The use of these methods as a complementary tool for quality controls is highly recommended to avoid undesirable misclassifications
Evidence for subaerial development of the Caribbean oceanic plateau in the Late Cretaceous and palaeo-environmental implications
The formation of oceanic plateaus in the Pacific in the Mesozoic has been proposed to create major environmental impacts, including global anoxic events OAE-1 in the Aptian (ca. 120 Ma) and OAE-2 in the Cenomanian–Turonian (ca. 90 Ma). However, our understanding of the formation of these large volcanic systems and their environmental effects are strongly limited by difficulties in accessing them and characterising their volcanic evolution. In particular, it remains significant to determine whether Pacific oceanic plateaus experience a phase of subaerial volcanic activity as this has critical implications in terms of their environmental impacts. Herein we provide the first unequivocal evidence for an emergent volcanic phase of the Caribbean oceanic plateau in the Late Cretaceous. This subaerial phase is evidenced by accreted oceanic sequences in Colombia that include fallout tuffs with accretionary lapilli and lahar deposits. This facies assemblage, recognised for the first time in an oceanic plateau, reflects phreatomagmatic eruptions coeval with subaerial erosion on an oceanic island. This result, combined with previous evidence of subaerial development of the Ontong Java Plateau and Shatsky Rise, suggests that syn-volcanic emergence of oceanic plateaus was common in the Pacific during the Mesozoic. Although temporal and spatial scales of these emergences remain poorly constrained it confirms that emergence of the Caribbean plateau in the Late Cretaceous (ca. 90 Ma) could have actively contributed to atmospheric changes and the establishment of OAE-2. Significantly, emergence of the Caribbean plateau occurred synchronously to the beginning of its tectonic displacement between the Americas. We propose that this unusual volcanic and tectonic evolution led to drastic reduction of the flow of Pacific oxygenated bottom waters into the early Atlantic basin, leading to a series of regional anoxic events previously documented between the Coniacian and Santonian (OAE-3, ca. 89 to 84 Ma). In addition, emergence of the Caribbean Plateau in the early inter-American seaway could have facilitated migration of terrestrial organisms between the Americas in the Late Cretaceous. The formation of the Caribbean plateau had therefore a large range of possible environmental effects, from atmospheric to palaeo-oceanographic and biotic impacts
- …