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Carnivores play an important role in ecosystem functioning as apex predators. However, most carnivore species are threatened or have been extirpated in human-dominated landscapes. The Mediterranean region of central Chile is a biodiversity hotspot, but expansion of agricultural areas such as vineyards is degrading wildlife habitat. We estimated the species richness and composition of carnivore communities in remnant fragments of sclerophyllous forest-shrubland in the vineyard landscapes of central Chile to evaluate the effects of human disturbance at different spatial scales. We tested two hypotheses: (1) vineyard landscapes with higher levels of human disturbance support a lower diversity of native carnivores in fragments of remnant native vegetation compared to landscapes with larger areas of natural habitat, and (2) habitat specialists and generalists respond differentially to human influence at the habitat vs landscape spatial scale. We used camera traps at 12 sites across the study area and evaluated the impact of human disturbance indicators on the richness and detection frequency of carnivore species. We found that human population density negatively affected carnivore richness and was associated with a lower detection frequency of the Vulnerable guiña Leopardus guigna. The presence of domestic dogs also had a negative effect on the detection frequency of the guiña and the two native species of foxes, the culpeo Lycalopex culpaeus and South American grey fox Lycalopex griseus. We conclude that protecting remnants of native forest in vineyard landscapes is crucial for carnivore conservation in central Chile.
Options with extendable features have many applications in finance and these provide the motivation for this study. The pricing of extendable options when the underlying asset follows a geometric Brownian motion with constant volatility has appeared in the literature. In this paper, we consider holder-extendable call options when the underlying asset follows a mean-reverting stochastic volatility. The option price is expressed in integral forms which have known closed-form characteristic functions. We price these options using a fast Fourier transform, a finite difference method and Monte Carlo simulation, and we determine the efficiency and accuracy of the Fourier method in pricing holder-extendable call options for Heston parameters calibrated from the subprime crisis. We show that the fast Fourier transform reduces the computational time required to produce a range of holder-extendable call option prices by at least an order of magnitude. Numerical results also demonstrate that when the Heston correlation is negative, the Black–Scholes model under-prices in-the-money and over-prices out-of-the-money holder-extendable call options compared with the Heston model, which is analogous to the behaviour for vanilla calls.
In recent years, modified graphene has been used in various biomedical applications due to its excellent properties that allow the development of devices capable of detecting macromolecules within the human organism, also for biomolecular analysis, discovery of biomarkers, bioimaging and target delivery. These applications involve interactions between enzymes, proteins, peptides, DNA, RNA, etc. and modified graphene, therefore the study and the theoretical and experimental investigation of these interactions is essential for the development of nanobio-technology. For example, many applications based on using modified graphene to detect macromolecules require studying the changes in the properties of doped graphene when interacting with macromolecules. In this work, DFT and molecular dynamics methods were used to obtain results of the changes in energy density of states of graphene doped with iron when it is made to interact with coenzyme A. Besides, we presented a study of molecular dynamics in order to determine the quantum factors that guide the interaction graphene-coenzyme A. The system was studied in aqueous medium which it was simulated by the dielectric constant of water. The results confirm that the methodology presented in this work can be used to theoretically detect various macromolecules.
Important Bird and Biodiversity Areas (IBAs) are sites identified as being globally important for the conservation of bird populations on the basis of an internationally agreed set of criteria. We present the first review of the development and spread of the IBA concept since it was launched by BirdLife International (then ICBP) in 1979 and examine some of the characteristics of the resulting inventory. Over 13,000 global and regional IBAs have so far been identified and documented in terrestrial, freshwater and marine ecosystems in almost all of the world’s countries and territories, making this the largest global network of sites of significance for biodiversity. IBAs have been identified using standardised, data-driven criteria that have been developed and applied at global and regional levels. These criteria capture multiple dimensions of a site’s significance for avian biodiversity and relate to populations of globally threatened species (68.6% of the 10,746 IBAs that meet global criteria), restricted-range species (25.4%), biome-restricted species (27.5%) and congregatory species (50.3%); many global IBAs (52.7%) trigger two or more of these criteria. IBAs range in size from < 1 km2 to over 300,000 km2 and have an approximately log-normal size distribution (median = 125.0 km2, mean = 1,202.6 km2). They cover approximately 6.7% of the terrestrial, 1.6% of the marine and 3.1% of the total surface area of the Earth. The launch in 2016 of the KBA Global Standard, which aims to identify, document and conserve sites that contribute to the global persistence of wider biodiversity, and whose criteria for site identification build on those developed for IBAs, is a logical evolution of the IBA concept. The role of IBAs in conservation planning, policy and practice is reviewed elsewhere. Future technical priorities for the IBA initiative include completion of the global inventory, particularly in the marine environment, keeping the dataset up to date, and improving the systematic monitoring of these sites.
We analyse the evolution with redshift of the radial gradient of oxygen abundances in spiral disks resulting from our MULCHEM chemical evolution models, computed for galaxies of different sizes or masses, studying the relationships between the gradients and galaxy characteristics as the stellar mass, the size, the gas fraction or the star formation rate for z < 4.
Recently, low-density steels have received increased attention as promising alternatives for automotive applications of the next generation of Advanced High-Strength Steels (AHSS), considering that vehicle´s weight decrease has been the subject of intense interest. It is well-known that the addition of rare earth metals (REM) has a remarkable effect on shape control and the modification of inclusions. Also, REM additions affect the grain size refinement as well as the tendency to form oxides and sulfides. The aim of this research work was to determine the effect of REM (Ce, La) addition on the microstructure and mechanical properties of the Fe-30Mn-8Al-1.8C low-density steel in as-cast condition. In order to clarify the REM effect on the Fe-Mn-Al-C system, non-microalloyed (LD-NM) and REM microalloyed (LD-REM) specimens were examined in detail by means of light optical and scanning electron microscopy for microstructural characterization. In the same way, the primary and secondary phases founded in the studied steels were identified by X-ray diffraction (XRD). Meanwhile, in order to evaluate the mechanical properties, ten microhardness measurements were carried out on the overall bulk by the Vickers hardness testing. In general, the results showed a dendritic refinement effect due to the addition of REM to low-density steel. REM acted as effective inoculants agents which reduced the primary and secondary arm spacing. Also, the strong segregation tendency at the grain boundaries in the liquid phase was limited. XRD profiles revealed the presence of austenite, ferrite, κ and DO3 phases. Low density steel microalloyed with REM showed a moderate increase in hardness compared to the non-microalloyed steel in the as-cast condition.
Abnormalities in the hippocampus have been implicated in the pathophysiology of psychosis. However, it is still unclear whether certain abnormalities are a pre-existing vulnerability factor, a sign of disease progression or a consequence of environmental factors. We hypothesized that first-episode psychosis patients who progress to schizophrenia after one year of follow up will display greater volumetric and morphological changes from the very beginning of the disorder.
We studied the hippocampus of 41 patients with a first-episode psychosis and 41 matched healthy controls. MRI was performed at the time of the inclusion in the study. After one year, the whole sample was reevaluated and divided in two groups depending on the diagnoses (schizophrenia vs. non-schizophrenia).
Patients who progressed to schizophrenia showed a significantly smaller left hippocampus volume than control group and no-schizophrenia group (F = 3.54; df = 2, 77; P = 0.03). We also found significant differences in the morphology of the anterior hippocampus (CA1) of patients with first-episode psychosis who developed schizophrenia compared with patients who did not.
These results are consistent with the assumption of hyperfunctioning dopaminergic cortico-subcortical circuits in schizophrenia, which might be related with an alteration of subcortical structures, such as the hippocampus, along the course of the disease. According with these results, hippocampus abnormalities may serve as a prognostic marker of clinical outcome in patients with a first-episode psychosis.
The improvement in porcine embryo preservation and non-surgical embryo transfer (ET) procedures achieved in recent years represents essential progress for the practical use of ET in the pig industry. This study aimed to evaluate the effects of parity, weaning-to-estrus interval (WEI) and season on reproductive and embryonic parameters at day 6 after insemination of donor sows superovulated after weaning. The selection of donor sows was based on their reproductive history, body condition and parity. The effects of parity at weaning (2 to 3, 4 to 5 or 6 to 7 litters), season (fall, winter and spring), and WEI (estrus within 3 to 4 days), and their interactions on the number of corpus luteum, cysts in sows with cysts, number and quality of viable and transferable embryos, embryo developmental stage and recovery and fertilization rates were evaluated using linear mixed effects models. The analyses showed a lack of significant effects of parity, season, WEI or their interactions on any of the reproductive and embryonic parameters examined. In conclusion, these results demonstrate that fertilization rates and numbers of viable and transferable embryos collected at day 6 of the cycle from superovulated donor sows are not affected by their parity, regardless of the time of the year (from fall to spring) and WEI (3 or 4 days).
We review the state of our chemical evolution models for spiral and low mass galaxies. We analyze the consequences of using different stellar yields, infall rate laws and star formation prescriptions in the time/redshift evolution of the radial distributions of abundances, and other quantities as star formation rate or gas densities, in the Milky Way Galaxy; In particular we will study the evolution of the oxygen abundance radial gradient analyzing its relation with the ratio SFR/infall. We also compare the results with our old chemical evolution models, cosmological simulations and with the existing data, mainly with the planetary nebulae abundances.
We present the first submillimetric line survey of extragalactic sources carried out by APEX. The surveys cover the 0.8 mm atmospheric window from 270 to 370GHz toward NGC253, NGC4945 and Arp220. We found in NGC 253, 150 transitions of 26 molecules. For NGC 4945, 136 transitions of 24 molecules, and 64 transitions of 17 molecules for Arp 220. Column densities and rotation temperatures have been determinate using the Local Thermodinamical Equilibrium(LTE) line profile simulation and fitting in the MADCUBA IJ software. The differences found in ratios between the Galactic Center and the starburst galaxies NGC 4945 and NGC 253 suggest that the gas is less processed in the latter than in the Galactic Center. The high 18O/17O ratios in the galaxies NGC 4945 and NGC 253 suggest also material less processed in the nuclei of these galaxies than in the Galactic Center. This is consistent with the claim that 17O is a more representative primary product than 18O in stellar nucleosynthesis (Wilson and Rood 1994); Also, we did a Multitransitions study of H3O+ at 307GHz, 364GHz, 388GHz and 396GHz. From our non-LTE analysis of H3O+ in NGC253 with RADEX we found that the collisional excitation can not explain the observed intensity of the ortho 396 GHz line. Excitation by radiation from the dust in the Far-IR can roughly explain the observations if the H2 densities are relatively low. From the derived H3O+ column densities we conclude that the chemistry of this molecule is dominated by ionization produce by the starburst in NGC253 (UV radiation from the O stars) and Arp 220 (cosmic rays from the supernovae) and likely from the AGN in NGC4549 (X-rays ); Finally, we report, for the first time, the tentative detection of the molecular ion HCNH+ (precursor of HCN and HNC) toward a galaxy, NGC4945, abundance explain the claimed enhancement of HCN abundance in the AGN, due to the enhancement of the ionization rate by X-rays. The abundance is much larger than the Galactic center of the Milky Way.
We summarize the results obtained from our suite of chemical evolution models for spiral disks, computed for different total masses and star formation efficiencies. Once the gas, stars and star formation radial distributions are reproduced, we analyze the Oxygen abundances radial profiles for gas and stars, in addition to stellar averaged ages and global metallicity. We examine scenarios for the potential origin of the apparent flattening of abundance gradients in the outskirts of disk galaxies, in particular the role of molecular gas formation prescriptions.
The objective of this study was to assess the effectiveness of a catheter-related bloodstream infection (CR BSI) reduction programme and healthcare workers' compliance with recommendations. A 3-year surveillance programme of CR BSIs in all hospital settings was implemented. As part of the programme, there was a direct observation of insertion and maintenance of central venous catheters (CVCs) to determine performance. A total of 38 education courses were held over the study period and feedback reports with the results of surveillance and recommendations were delivered to healthcare workers every 6 months. A total of 6722 short-term CVCs were inserted in 4982 patients for 58 763 catheter-days. Improvements of compliance with hand hygiene was verified at the insertion (87·1–100%, P < 0·001) and maintenance (51·1–72·1%, P = 0·029) of CVCs; and the use of chlorhexidine for skin disinfection was implemented at insertion (35·7–65·4%, P < 0·001) and maintenance (33·3–45·9%, P < 0·197) of CVCs. There were 266 CR BSI incidents recorded with an annual incidence density of 5·75/1000 catheter-days in the first year, 4·38 in the second year [rate ratio (RR) 0·76, 95% confidence interval (CI) 0·57–1·01] and 3·46 in the third year (RR 0·60, 95% CI 0·44–0·81). The education programme clearly improved compliance with recommendations for CVC handling, and was effective in reducing the burden of CR BSIs.
To assess the prescription of benzodiazepines (BZD) in elderly patients, and to explore any gender differences.
Six hundred and fifty-four patients (≥ 65) admitted in an emergency service of a general hospital due to a fall. BZD use information was collected (dose, half-life profile).
BZD are significantly more prescribed to women (47.6%) than men (36.1%) (X2 = 8.097, P = 0.004). We conducted a logistic regression analysis using as dependent variable taking or not BZD and sex as the independent one, covariating the model by age. We noted that sex remains significant despite enter the age variable in the model (OR = 1.5, P = 0.013). A total of 21.6% of patients consumed intermediate or long half-life BZDs, appearing a greater tendency to prescribe such BZD to women (X2 = 3.606, P = 0.058). In the 58.0% of prescriptions, prescribed dose was higher than the recommended for the elderly. The percentage is significantly higher for men (70.0%) than women (53.1%). Furthermore, a total of 54 prescriptions (15.8%) were even higher than the recommended adult dose, with no significant differences between men and women.
We found evidence of a higher prescription of BZD in women independently of age. Despite not being recommended, prescription of intermediate or long half-life BZD continues, in a slightly higher manner in women. BZD are prescribed above the recommended dose for elderly in a large number of patients, especially in men. A considerable proportion of elderly patients (15.8%) consume BZD doses even higher than the recommended for adults.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
Tephritid pests controlled through the sterile insect technique (SIT) are mass-reared and subsequently released in affected areas. Several quality parameters are currently used to test adults, but none take into account interactions with a predator. When sterile males are released in the field, they will need to avoid predators until they reach sexual maturity and survive long enough to mate with wild females. Spiders are one of the most common predators that flies may encounter in release sites. In this study, we evaluated the antipredator behavior of a mass-reared sterile unisexual strain (‘Tapachula-7’) of the Mexican fruit fly Anastrepha ludens (Diptera: Tephritidae) against their spider predators. We sampled spiders in citrus trees to determine which families could be more common. We established the baseline activity rates of sterile Tapachula-7 (Tap-7) flies in comparison with wild flies. We also tested the behavior of the fertile and sterile bisexual strain and wild flies against hunting spiders (Family Salticidae) and orb building spiders (Family Tetragnathidae). We recorded 18 spider families, with Salticidae being the most dominant. Tap-7 flies diminished their activity in comparison with wild males at 1800 h but showed similar activity levels earlier in the day. When exposed to orb-web spiders (Leucauge venusta), Tap-7, fertile and sterile males from the bisexual strain had similar rates of survival, but Tap-7 males showed lower survival than wild males. Against hunting spiders (Phidippus audax), wild males had higher probability of defensive wing displays, but there was no difference in spider attack rates. In general, sterile Tap -7 males performed as well as males from the bisexual strain, although they had lower survival than wild males. This could be due to either mass-rearing and/or irradiation effects. We recommend the use of the defensive wing display behavior as a quality parameter and propose a rapid and effective method to evaluate fly activity. The efficiency of SIT will be improved if released sterile males have the same antipredator repertoire as their wild counterparts.
In traditional transit timing variations (TTVs) analysis of multi-planetary systems, the individual TTVs are first derived from transit fitting and later modelled using n-body dynamic simulations to constrain planetary masses. We show that fitting simultaneously the transit light curves with the system dynamics (photo-dynamical model) increases the precision of the TTV measurements and helps constrain the system architecture. We exemplify the advantages of applying this photo-dynamical model to a multi-planetary system found in K2 data very close to 3:2 mean motion resonance, K2-19. In this case the period of the larger TTV variations (libration period) is much longer (>1.5 years) than the duration of the K2 observations (80 days). However, our method allows to detect the short period TTVs produced by the orbital conjunctions between the planets that in turn permits to uniquely characterise the system. Therefore, our method can be used to constrain the masses of near-resonant systems even when the full libration curve is not observed.
In the coast of Galicia an average of 200 stranded cetaceans are reported annually. From 1990 to 2013, 21 individuals of four species of the family Ziphiidae were found: 15 Cuvier's beaked whales (Ziphius cavirostris), two Sowerby's beaked whales (Mesoplodon bidens), one True's beaked whale (Mesoplodon mirus) and one Blainville's beaked whale (Mesoplodon densirostris), as well as two unidentified ones. These were the first records in Galicia for True's beaked whale and Blainville's beaked whale. The study of the distribution of oceanic species considering only stranded animals has limitations, but is a good approach to this not well-known cetacean family. Due to the small number of individuals of the different species, statistical analyses for geographic or seasonal patterns were only carried out for the Cuvier's beaked whales. Between the periods of 1990–2002 and 2003–2013 significant differences were found for geographic and seasonal occurrence patterns. Over the last decade strandings were located only in the north area of the region, mainly during the spring season, while in the previous decade they were located along the three considered areas and only in autumn and winter.
This contribution presents a critical review about some materials used in dosimetry and the interest that has emerged on topaz recently. In addition, results about the feasibility for synthesizing topaz by the HYSY-CVD route using Na2SiF6 and Al2O3 are shown. Synthesis tests in nitrogen atmosphere were conducted varying temperature (700 and 750°C) and time (60 and 90 min) while maintaining constant the amounts of Al2O3 and Na2SiF6. The microstructural characterization by XRD, SEM and EDS revealed the succesful formation of topaz and aluminium fluoride.