Pulsed DC reactive magnetron sputtering of vanadium dioxide thermochromic thin films

Vanadium oxides are an important class of materials with a large diversity of physical and chemical properties which derive from a range of single or mixed valences and a large variety of structures. They are already being used in many technological applications such as electrical and optical switching devices, light detectors, temperature sensors, etc. There has been a great interest in a particular phase, VO2(M), due to its thermochromic behaviour near room temperature which allows the development of smart windows with active control of the solar spectrum, for energy efficiency purposes. However, stoichiometric VO2 is difficult to deposit because of a narrow stability range due to the complex vanadium–oxygen reactive system. In this work, vanadium oxide thin films were synthesised on glass substrates by reactive pulsed direct current magnetron sputtering from a vanadium metal target in an O2/Ar atmosphere. Different processing conditions have been chosen in order to evaluate their influence on the crystal phases formed, surface morphologies and thicknesses and optical performance. The films were characterised by X-ray diffractometry in order to examine the crystal structure and identify the phases present in different films. The obtained VO2(M) films were thereafter analysed in terms of surface morphology by scanning electron microscopy and the characteristic reversible semiconductor-metal transition of the VO2 films was evaluate by optical spectrophotometry in the ultraviolet-visible-near infrared.Fundação para a Ciência e a Tecnologia (FCT) SFRH/BD/40512/2007

New trends in the management of postpartum haemorrhage

If the World Health Organization (WHO) global maternal mortality by cause is examined for the period 1997-2007, haemorrhage constitutes 35% of deaths. Published data from the triennium 2008-2010 in South Africa indicate that if non-pregnancy-related sepsis is excluded, haemorrhage still ranks with hypertension as the most common cause of maternal deaths (24%). So how can anaesthetists improve this situation and save lives? Sadly, the main reason for the appalling figures in respect of maternal deaths in sub-Saharan Africa is poor access to basic obstetric care, blood products and basic commodities, such as electricity, for the refrigeration of blood and drugs such as oxytocin.1 Nevertheless, there are many areas where management, and hence outcomes, could be improved. This article addresses the crucial issues of predicting haemorrhage, assessing blood loss, point-of-care monitoring and transfusion protocols. Surgical techniques and oxytocic therapy are equally important, and are the subject of many other reviews.Keywords: postpartum haemorrhage; management; new trend

Surface laser-glazing of plasma-sprayed thermal barrier coatings

Atmospheric plasma-sprayed (APS) ZrO2–8%WtY2O3 thermal barrier coatings (TBCs) were subjected to a CO2 continuous wave laser-glazing process in order to generate an external dense layer produced by different processing parameters. For that purpose, different beam scanning speeds and track overlapping were chosen. Surface roughness has been reduced significantly after laser-glazing. Despite the surface crack network, all laser-glazed specimens presented a fully dense and porous free external layer with a columnar microstructure. Surface cracks along the densified layer were found to have tendency to be oriented in two perpendicular directions, one in the direction of the laser beam travel, the other perpendicular to it. Moreover, the cracks parallel to the beam moving direction are found to be on the overlapping zone, coinciding with the edge of the subsequent track. The cracks along the densified layer are vertical and tend to branch and deviate from the vertical direction within the porous PS coating. The largest overlapping allied to the smallest amount of irradiated energy generated the most uniform layer with the shortest crack branches within the PS coating. For the as-sprayed coating, the XRD results revealed mainly t0 non-transformable tetragonal zirconia with a small percentage of residual monoclinic zirconia. All glazed coatings presented only t0 non-transformable tetragonal zirconia with some variations on preferable crystal orientation.União Europeia (UE). Fundo Europeu de Desenvolvimento Regional (FEDER).Fundação para a Ciência e a Tecnologia (FCT) - Project POCTI/CTM44590/2002

Evidences on overweight of regular blood donors in a center of Southern Italy

Objective: Smoking, unhealthy diet and obesity, sedentary behavior and inability to maintain adequate exercise have significant consequences for several chronic disorders. Blood centers can play a public health role in obesity surveillance and interventions. The purpose study was to evaluate the health status of the blood donors by monitoring the nutritional habits and lifestyle. Methods: A descriptive cross-sectional face-to-face questionnaire was developed. It included a 41 item dietary assessment, reporting semi-quantitative food frequency, dietary behavior and questions on self-rated health status. Donors were regular repeat blood donors, eligible to donate. Results: Of the 2468 blood donors enrolled between July 2017 and January 2018, 1390 were repeat donors. Only 205 agreed to respond to the questionnaire. Data showed that donors followed mainly a Mediterranean diet and had more awareness to lifestyle, women more than men, in comparison with general population. The prevalence of overweight was found 50.7% in men and 16.9% in women. Conclusions: Overweight and obesity are common among regular blood donors and it is more frequent in men than women. The female blood donors seem to be characterized by better knowledge on the relationship between lifestyle and health, and by a better “putting into practice” of the information possessed

Post Quantum Cryptography from Mutant Prime Knots

By resorting to basic features of topological knot theory we propose a (classical) cryptographic protocol based on the `difficulty' of decomposing complex knots generated as connected sums of prime knots and their mutants. The scheme combines an asymmetric public key protocol with symmetric private ones and is intrinsecally secure against quantum eavesdropper attacks.Comment: 14 pages, 5 figure

An individual-based Model of the Red Alga Agarophyton chilense unravels the complex demography of Its intertidal stands

Algal demographic models have been developed mainly to study their life cycle evolution or optimize their commercial exploitation. Most commonly, structured-aggregated population models simulate the main life cycle stages considering their fertility, growth and survival. Their coarse resolution results in weak predictive abilities since neglected details may still impact the whole. In our case, we need a model of Agarophyton chilense natural intertidal populations that unravels the complex demography of isomorphic biphasic life cycles and be further used for: (i) introduction of genetics, aimed at studying the evolutionary stability of life cycles, (ii) optimizing commercial exploitation, and (iii) adaptation for other species. Long-term monitoring yield 6,066 individual observations and 40 population observations. For a holistic perspective, we developed an Individual-Based Model (IBM) considering ploidy stage, sex stage, holdfast age and survival, frond size, growth and breakage, fecundity, spore survival, stand biomass, location and season. The IBM was calibrated and validated comparing observed and estimated sizes and abundances of gametophyte males, gametophyte females and tetrasporophytes, stand biomass, haploid:dipoid ratio (known as H:D or G:T), fecundity and recruitment. The IBM replicated well the respective individual and population properties, and processes such as winter competition for light, self-thinning, summer stress from desiccation, frond breakage and re-growth, and different niche occupation by haploids and diploids. Its success depended on simulating with precision details such as the holdfasts' dynamics. Because "details" often occur for a reduced number of individuals, inferring about them required going beyond statistically significant evidences and integrating these with parameter calibration aimed at maximized model fit. On average, the population was haploid-dominated (H:D > 1). In locations stressed by desiccation, the population was slightly biased toward the diploids and younger individuals due to the superior germination and survival of the diploid sporelings. In permanently submerged rock pools the population was biased toward the haploids and older individuals due to the superior growth and survival of the haploid adults. The IBM application demonstrated that conditional differentiation among ploidy stages was responsible for their differential niche occupation, which, in its turn, has been argued as the driver of the evolutionary stability of isomorphic biphasic life cycles.info:eu-repo/semantics/publishedVersio

Influence of oxygen/argon pressure ratio on the morphology, optical and electrical properties of ITO thin films deposited at room temperature

Transparent conductive oxides (TCOs) such as indium tin oxide (ITO) thin films onto glass substrates are widely used as transparent and conductive electrodes for a variety of technological applications including flat panel displays, solar cells, smart windows, touch screens, etc. ITO films on glass and polycarbonate (PC) substrates were prepared at room temperature (RT) and at different PO2 . The films were characterized in terms of the surface roughness (d), sheet resistance, the refractive index (n) and extinction coefficient (k). The free carrier density (nc) and the carrier mobility (m) of the ITO (In2O3:Sn) films were measured and studied. The nc and m values vary in different ratio of oxygen partial pressure ðPO2 Þ of ITO deposition. The observed changes in the ITO film resistivity are due to the combined effect of different parameter values for nc and m. From AFM analysis and spectra calculations, the surface roughness values of the ITO films were studied and it was observed that the d values were lower than 15 nm. The energy band gap Eg ranges from 3.26 eV to 3.66 eV as determined from the absorption spectrum. It was observed an increase on the energy band gap as the PO2 decrease in the range of 20–2% PO2 . The Lorentz oscillator classical model has also been used to fit the ellipsometric spectra in order to obtain both refractive index n and extinction coefficient k values.Fundação para a Ciência e a Tecnologia (FCT)

Haploid females in the isomorphic biphasic life-cycle of Gracilaria chilensis excel in survival

Background Conditional differentiation is one of the most fundamental drivers of biodiversity. Competitive entities (usually species) differ in environmental or ecological niche enabling them to co-exist. Conditional differentiation of haploid and diploid generations is considered to be a requirement for the evolutionary stability of isomorphic biphasic life-cycles and the cause for the natural occurrence of both phases at uneven abundances. Theoretically, stage dependent survival rates are the most efficient way to explain conditional differentiation. Results We tested for conditional differentiation in survival rates among life stages (haploid males, haploid females, and diploids) of Gracilaria chilensis, an intertidal red alga occurring along the Chilean shores. Therefore, the fate of individuals was followed periodically for 3 years in five intertidal pools and, for the first time in isomorphic red algae, a composite model of the instantaneous survival rates was applied. The results showed the survival dependency on density (both competition and Allee effects), fertility, age, size, season and location, as well as the differentiation among stages for the survival dependencies of these factors. The young haploid females survived more than the young of the other stages under Allee effects during the environmentally stressful season at the more exposed locations, and under self-thinning during the active growth season. Furthermore, fertile haploid females had a higher survival than fertile haploid males or fertile diploids. Conclusions Here, we show a survival advantage of haploids over diploids. The haploid females probably optimize their resource management targeting structural and physiological adaptations that significantly enhance survival under harsher conditions. In a companion paper we demonstrate a fertility advantage of diploids over haploids. Together, the survival and fertility differentiation support the evolution and prevalence of biphasic life-cycles.info:eu-repo/semantics/publishedVersio

Dating minerals by ID-TIMS geochronology at times of in situ analysis: selected case studies from the CPGeo-IGc-USP laboratory

Since 1964, the Center for Geochronological Research - CPGeo, one of the interdepartmental centers of the Instituto de Geociências (IG) of São Paulo University, has developed studies related to several geological processes associated with different rock types. Thermal Ionization Mass Spectrometry Isotopic Dilution (ID-TIMS) has been the technique widely used in the CPGeo U-Pb Laboratory. It provides reliable and accurate results in age determination of superposed events. However, the open-system behavior such as Pb-loss, the inheritance problem and metamictization processes allow and impel us to a much richer understanding of the power and limitations of U-Pb geochronology and thermochronology. In this article, we present the current methodology used at the CPGeo-IGc-USP U-Pb laboratory, the improvements on ID-TIMS method, and report high-precision U-Pb data from zircon, monazite, epidote, titanite, baddeleyite and rutile from different rock types of several domains of the Brazilian south-southeast area, Argentina and Uruguay.O Centro de Pesquisas Geocronológicas (CPGeo), um dos centros interdepartamentais do Instituto de Geociências (IG) da Universidade de São Paulo (USP), desde 1964 desenvolve estudos relacionados a diversos processos geológicos que se associam a diferentes tipos de rochas. A técnica amplamente utilizada no Laboratório U-Pb é a diluição isotópica por espectrometria de massa termo ionizada (ID-TIMS). Esta sistemática proporciona resultados bastante confiáveis e precisos na determinação das idades de eventos geológicos superpostos. Entretanto, o comportamento de sistema aberto como perda de Pb, problemas de herança isotópica e processos de metamictização, nos permite o entendimento do poder e limitação da geocronologia e termocronologia U-Pb. Neste artigo apresentamos a metodologia atualmente utilizada no Laboratório U-Pb do CPGeo-IGc-USP, as melhorias atingidas na técnica ID-TIMS e alguns dados obtidos em zircão, epídoto, titanita, baddeleyita e rutilo de diferentes tipos de rochas de alguns domínios da região sul-sudeste brasileira e da Argentina e Uruguai.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP