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The Bay of Málaga is located in a high biodiversity and productivity area that harbours a wide variety of commercial species exploited by different fishing fleets. Benthic and demersal fauna from circalittoral soft bottoms have been studied using a benthic dredge (BD) (8 sampling stations) and an otter trawl (OT) (8 sampling stations on a seasonal basis). Some sediment and water column variables, as well as the trawling activity, have also been studied and used for analysing their linkage with the fauna. A total of 287 species have been found in these bottoms and fish, molluscs and crustaceans represented the most diverse and abundant faunistic groups. A new record of the decapod Hippolyte leptometrae for Spanish waters is also included in this study. Some multivariate analyses using BD samples indicated the presence of three assemblages, but these seem to represent different facies of a single benthic community due to the absence of acute sediment changes and significant differences in the fauna. OT samples only displayed differences related to seasons but not to sediment types or depth. These seasonal differences seem to be linked to biological and ecological features of both dominant and/or commercial species. Mud and organic matter contents (%OM) in sediment, as well as the temperature, were the main variables linked to the spatial distribution of the benthic community identified with BD, whereas medium and coarse sand as well as gravel contents were the main variables linked to the changes of the epibenthic and demersal assemblage resulting from OT samples. The information of this study is of importance for improving the knowledge on the biodiversity of circalittoral soft bottoms of the Mediterranean and Alboran Sea as well as for the potential creation of a Marine Fisheries Reserve in the Bay of Málaga.
Predation by Engytatus varians (Distant) adults on different development stages of the prey species Bactericera cockerelli (Sulcer) (egg, second, and third nymphal instars), Spodoptera exigua (Hübner) and Spodoptera frugiperda (J. E. Smith) (egg, first, and second larval instars) was evaluated using tomato (Solanum lycopersicum L.) leaflets or plants. These insects are the primary pest of several agriculturally important crops. The influence of E. varians age on the predation capacity was also analysed. Engytatus varians females consumed significantly more B. cockerelli eggs and nymphs than males. Additionally, female predators consumed significantly more second than third instar prey at two predator ages, while males consumed significantly more the second instar than third instar prey at all predator ages. In most of the cases, females also consumed significantly more S. exigua and S. frugiperda eggs than males; however, in terms of larvae consumption, this difference was observed only in some predator ages. Females consumed more the first than second instar S. exigua than males, whereas this behaviour was only observed in males when the predators were 15 and 17 days old. No significant differences were observed in the consumption of first and second instar of S. frugiperda for both sexes of the predators. Predator age did not cause any systematic effects on the predation rates of any prey species. Based on these results, we confirmed that E. varians has potential as a biological control agent for B. cockerelli and also for the Spodoptera species bioassayed.
Here we report the production of monodisperse microbubbles by taking advantage of the large values of both the pressure gradients and of the local velocities existing at the leading edge of airfoils in relative motion with a liquid. It is shown here that the scaling laws for the bubbling frequencies and the bubble diameters are identical to those found in microfluidics. Therefore, the metre-sized geometry presented here is a feasible candidate to circumvent the inherent problems of using micron-sized geometries in real applications – namely, wettability, the low productivity and the clogging of the microchannels by particles or other impurities.
The photometric behaviour of AGK3-0°965, the central star of the bipolar planetary nebula NGC 2346, has been monitored photometrically for several months at the Observatorio Astronómico Nacional at Tonantzintla and San Pedro Mértir, Mexico. A model is proposed in which the eclipses were caused by the passage of an elongated cool dust cloudlet of size ~ 2–5 × 1012 cm and total mass ~ 10−12 M⊙. This model can explain most of the observations. The velocity of the cloud in the direction of the major axis of the projected central binary orbit is vp = 0.14 km s−1. Another warmer (T ≲ 1000 K) circumstellar cloud is responsible for the infrared excess at wavelengths from 3 to 12 μm. Its emission, as seen from the Earth, has not changed significantly at λ > 3 μm during the past twelve years, as shown by new infrared observations also reported. Its most relevant physical properties are still to be determined. The present results provide the first evidence of a dense circumstellar cloudlet of mass similar to that of a minor planet which is probably the result of the fragmentation of a disk or toroid around the central star of NGC 2346. Although the presence of many other similar cloudlets in its vicinity is expected, the probability of similar events occurring in the next few hundred years is very small.
The details of the present work will be published in the Revista Mexicana de Astronomía y Astrofísica.
The sexual performance of Anastrepha ludens males of the Tapachula-7 genetic sexing strain, produced via selection based on mating success, was compared with that of males produced without selection in competition with wild males. Mating competition, development time, survival, mass-rearing quality parameters and pheromone production were compared. The results showed that selection based on mating competitiveness significantly improved the sexual performance of offspring. Development time, survival of larvae, pupae and adults, and weights of larvae and pupae increased with each selection cycle. Differences in the relative quantity of the pheromone compounds (Z)-3-nonenol and anastrephin were observed when comparing the parental males with the F4 and wild males. The implications of this colony management method on the sterile insect technique are discussed.
The historical monuments such as cathedrals, public buildings and so on, are a fundamental part of artistic heritage of a country. They reflect, ultimately, much of its culture and history. For several decades, their aspect has been seriously changed by graffiti, which clearly endangers their preservation state and causes loss of their esthetic appearance and historic value. This damages seriously the self-esteem of residents who witness the continued and strong degradation of their cultural heritage. The aim of this work is to study the removal of graffiti from a characteristic stone which is used in Morelia (México) as the raw material for architectural monuments, using a high power diode laser treatment. We concluded that continuous wave regime leads to better results than modulated wave regime; additionally, a two laser passes process demonstrated a high performance.
In June 2011, a cluster of suspected cases of Guillain–Barré syndrome (GBS), which can follow Campylobacter jejuni infection, was identified in San Luis Río Colorado (SLRC), Sonora, Mexico and Yuma County, Arizona, USA. An outbreak investigation identified 26 patients (18 from Sonora, eight from Arizona) with onset of GBS 4 May–21 July 2011, exceeding the expected number of cases (n = 1–2). Twenty-one (81%) patients reported antecedent diarrhoea, and 61% of 18 patients tested were seropositive for C. jejuni IgM antibodies. In a case-control study matched on age group, sex, ethnicity, and neighbourhood of residence, all Arizona GBS patients travelled to SLRC during the exposure period vs. 45% of matched controls (matched odds ratio 8·1, 95% confidence interval 1·5–∞). Exposure information and an environmental assessment suggested that GBS cases resulted from a large outbreak of C. jejuni infection from inadequately disinfected tap water in SLRC. Binational collaboration was essential in investigating this cross-border GBS outbreak, the first in mainland North America since 1976.
The effect of four temperatures (18, 20, 25 and 30°C) on pupa development and sexual maturity of Anastrepha obliqua adults was investigated under laboratory conditions. The results showed that the duration of the pupal stage decreased with an increase in temperature (29, 25, 13 and 12 days, respectively), and maintaining the pupae at 18°C and 20°C results in a low percentage of pupation, pupa weight loss and lesser flying ability. However, it significantly favored sexual behavior, a higher proportion of sexual calls and matings. While enhanced pupa development was observed at a temperature of 30°C, adults had low sexual efficiency, as well as a lower proportion of calls and matings. Gas chromatography-mass spectrometry (GC-MS) analysis of male volatiles showed that the amount of (Z,E)-α-farnesene did not vary among males from pupae reared at different temperatures; however, less (E,E)-α-farnesene was emitted by males obtain from pupa reared at 30°C. Male flies kept at 30°C during their larval stage had more (Z)-3-nonenol and, also, an unknown compound was detected. The fecundity of the females was higher at low temperatures. Regarding fertility, no significant differences were found between temperatures. The optimal temperature on pupa development was 25°C when males displayed ideal attributes for rearing purposes.
This paper presents simulation results for a microwave (2.45 GHz) plasma reactor, operated by an axial injection torch (AIT). The study gives a two-dimensional description of the AIT-reactor system, based on an electromagnetic model (that solves Maxwell's equations adopting a time-harmonic description, yielding the distribution of the electromagnetic fields and the average power absorbed by the plasma), and a hydrodynamic model (that solves the Navier-Stokes' equations for the flowing neutral gas, yielding the distribution of mass density, pressure, temperature, and velocities). Comparison between model results and experimental measurements reveal common variation trends, with changes in the reactor height, for the power reflected by the system, and yield a qualitative agreement for the axial profile of the gas rotational temperature. Model results, such as the power transmission coefficient and the gas temperature, are particularly dependent on the reactor dimensions, the electron density and temperature, and the gas input flow, which indicates that simulations can be used to provide general guidelines for device optimization.
Tropical dry forests may be among the world's most threatened ecosystems, but few studies have objectively quantified their status and threats. This study analysed Venezuelan dry forests at multiple scales, assessing status, present threats and the policy context shaping their future. Historical and current dry forest cover at both national and local scales were contrasted, and a set of quantitative risk assessment criteria applied. While dry forests were vulnerable nationally, in northern-central locations they were endangered. Clearing for cattle ranching and for intensive and subsistence agriculture were the principal factors driving dry forest loss at the national scale, while at a local level, urbanization and fire seemed to be the primary threats. The analysis emphasized the separation of risk assessment from the very different task of establishing conservation priorities; high risk areas may not necessarily be the highest priority for investment, and policy makers may become explicitly aware of the spatial scale at which their policies are implemented, as well as how these policies may affect or be affected by the status of ecosystems beyond their area of influence. The main challenge to future dry forest conservation is a paucity of explicit policies for management and use. However, scientifically-based management can support positive dry forest policies in many ways, including identifying locations and protocols for ecological restoration, maintaining seed banks, quantifying baseline conditions, and monitoring genetic diversity and other indicators.
The need of techniques for determining the mechanical properties of
thin films, e.g. hardness coatings on ion beam treated surfaces has
prompted a study of the microindentation hardness technique. The present
interest is driven to a good understanding of the adhesion, friction,
wear, and indentation processes. In most of the solid-solid interfaces
of technological relevance, it occurs contact in many asperities, and
this is why the study of fundamental properties of micro-mechanic and
tribology of surfaces and interfaces is very important. The recent
developments of different microscopic techniques based on tips and force
surface devices (i.e. AFM, FM, LFM) allowed investigations of
interfacial problems with high resolution and have led to the nanoscale
regime the mechanical properties study for a wide spectrum of materials.
In this work a method for Young's modulus determination of hard coatings
multilayers of TiN/ZrN is evaluated. This method is based on AFM and
spectroscopy-force modes [1-2].
The lymphocyte profile of 521 HIV-infected subjects hospitalized at Jackson Memorial (2001–2002) was compared across main respiratory diseases. Study data included medical history and all laboratory evaluations performed during hospitalization. Community-acquired pneumonias (CAP, 52%), Pneumocystis jiroveci pneumonia (PCP, 24%), tuberculosis (TB, 9%) and non-tuberculous mycobacterial diseases (NTM, 12%) were the most frequent causes of admission. Patients hospitalized with PCP and NTM exhibited the lowest CD4 counts (P=0·003). PCP patients had the highest B-cell percentages (P=0·04). CAP patients had the highest CD8 and CD4 percentages and the lowest percentage of Natural Killer (NK) cells and viral burdens. TB patients exhibited the lowest NK-cell (11·4±6·3) and B-cell percentages (13·6±12) and the highest CD8 (59±14) percentage. NTM patients, in contrast, had the highest NK-cell percentages of the groups (19·1±11·6, P=0·01). Additionally, immune responses associated with respiratory pathogens differed in HIV-infected patients with CD4+ cells above and below 200 counts.
The mechanisms are studied for enhanced formation of C54–TiSi2 at about 700 °C when rapid thermal annealing at 3 °C/s in N2 is performed on 32-nm-thick codeposited Ti–5.9 at.% Ta on Si(100) single-crystal substrates. The enhancement is related to an increased C54–TiSi2 nucleation rate due to the development of a multilayered microstructure. The multilayer microstructure forms at temperatures below 600 °C with the formation of an amorphous disilicide adjacent to the Si substrate and a M5Si3 (M = Ti, Ta) capping layer. This amorphous disilicide crystallizes at higher temperatures to C49–TiSi2. The multilayer microstructure introduces an additional interface that increases the area available for the heterogeneous nucleation of C54. The capping layer is identified as hexagonal Ti 5Si3 or its isomorphous compound (Ti1–xTax)5Si3. Crystal simulations demonstrate that C54(040) has a lattice mismatch of 6–7% relative to Ti5Si3(300) suggesting that a pseudomorphic epitaxial relationship may lower the interfacial energy between these two phases and reduce the energy barrier for C54 nucleation. A C40 disilicide phase was also observed at temperatures above that required to form C54–TiSi2 suggesting that, in the present experiments, the C40 phase does not play a major role in catalyzing C54 formation.
The X-ray powder diffraction pattern of the room temperature phase of Cd4GeSe6, a II4 □ IV VI6 semiconducting material, has been recorded and evaluated. This material crystallizes in the monoclinic space group Cc [No. 9] with a=12.847(3), b=7.407(2), c=12.854(2) Å, β=109.82(1)°, and Z=4. The powder diffraction pattern was also used to refine the crystal structure of this material employing the Rietveld method. The refinement of 56 parameters led to RWP=13.2%, RP=9.95% for 3751 step intensities and RB=7.05% and RF=5.20% for 833 reflections. Cd4GeSe6 can be considered a defect “adamantane-structure” material with a sphalerite-related superstructure.
The room temperature X-ray powder diffraction pattern of Fe2GeSe4, a II2 □ IV VI4 semiconducting compound, has been recorded and evaluated. This material was found to be orthorhombic, a=13.069(1), b=7.559(1), c=6.2037(6) Å, V=612.83(9) Å3, Z=4, Dx=5.42 gcm−3. The structure refinement carried out using the Rietveld method indicated that this material crystallizes in space group Pnma (No. 62) with an olivine type of structure. The refinement of 33 parameters led to RWP=15.3%, RP=10.2% for 5251 step intensities and RB=9.44% and RF=9.36% for 913 reflections.
Laryngeal papillomatosis is one of the first diseases where interferon (IFN) was found to be effective. In 1983, a programme for the treatment of all such cases started in Cuba. Up to December 1991, 125 patients (92 children, 33 adults) have been treated: 102 with leucocyte IFN-α, 12 with recombinant IFN-α-2b, and 11 have received both preparations. Case management consisted of surgical removal of the lesions followed by an IFN schedule starting with 105 IU/kg of weight in children or 6 × 106 IU in adults, i.m. daily. The dose was progressively reduced, as long as no relapses occurred. At the end of the one-year schedule the doses were reduced to 5 × 104 IU/kg in children or 3 × 106 IU in adults, weekly. If there was a relapse, it was removed surgically and the patient returned to a higher dose level. Most cases (89; 71 per cent) have not relapsed after the treatment; 60 of them have been followed for more than three years. In those with relapses, the frequency of recurrence decreased in all but four patients. The treatment seemed to be more effective if initiated less than three months after the disease onset. The tracheostomy could be removed in five out of seven patients who needed it before the IFN treatment and was necessary in only three new cases during IFN treatment. In two of these, decannulation was possible later on. In a total of 14 patients relapses persisted after several cycles of IFN treatment. They were considered resistant to such treatment. No severe side effects were reported. The most frequent ones were fever, drowsiness, increased bronchial secretion, chills and headache. The establishment of this programme has maintained the disease under control in Cuba.
Recent X-ray single-crystal diffraction studies have shown that CuFeSe2 crystallizes in the tetragonal system with space group P2c [, No. 112], Z = 4, with a =5.530(1) Å and c = 11.049(2) Å, c/a = 1.998. This material had been reported as pseudocubic with a =5.53 Å. The purpose of this paper is to present new X-ray powder diffraction data for CuFeSe2 and to compare the results with those reported for eskebornite, a mineral with ideal chemical composition CuFeSe2, and with those obtained from single-crystal structure data.