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A 6–18 GHz high-power amplifier (HPA) design in GaN on SiC technology is presented. This power amplifier consists of a two-stage corporate amplifier with two and four transistors, respectively. It has been fabricated on UMS using their 0.25 µm gate length process, GH25. A study of the suitable attachment method and measurement on wafer and on jig are detailed. This HPA exhibits an averaged output power of 39.2 dBm with a mean gain of 11 dB in saturation and a 24.5% maximum power added efficiency in pulse mode operation with a duty cycle of 10% with a 25 µs pulse width.
The Endangered Cuvier's gazelle Gazella cuvieri is an endemic ungulate of north-western Africa. Information on the species has been based primarily on non-systematic surveys, and the corresponding status estimates are of unknown quality. We evaluate the effectiveness and efficiency of two field methods for systematic surveys of populations of Cuvier's gazelle in arid environments: distance sampling (based on sightings) and sampling indirect sign (tracks and scats). The work was carried out in the north-western Sahara Desert, in Morocco, where what is possibly the largest population of Cuvier's gazelle persists. A logistically viable survey was conducted over a total area of c. 20.000 km2 in 10 expeditions during 2011–2014. A total of 67 sites were surveyed, with 194 walking surveys (2,169 km in total). Gazelle signs were detected at 50 sites, and gazelles were sighted at 21 sites (61 individuals). We found a relationship between sightings and abundance indices based on indirect sign, which could be useful for population monitoring or ecological studies. Additionally, the data could be used in occupancy modelling. Density estimates based on distance sampling required considerable effort; however, it is possible to survey large areas during relatively short campaigns, and this proved to be the most useful approach to obtain data on the demographic structure of the population.
This paper focus on evaluating the ability to use Mexican fly ash (FA) and copper slag (CS) to produce alkali cements (0% OPC) or hybrid cements (20% OPC + 80% fly ash). The alkali activators used were two: 8 M NaOH solution for alkali cements and NaCl with sodium silicate for hybrid cement (HYC). Results of mechanical testing and characterization of the reaction products formed after 2 and 28 days are presented and discussed. Mechanical strength in some cases exceeded 20 MPa, at 2 days curing. The chemical characterization techniques used were X-Ray Diffraction (XRD) and scanning electron microscopy (SEM).
Objective: To longitudinally analyze the course of cognitive dimensions in schizophrenic women over a period of 31 years. Method: Accidental sampling. Developmental longitudinal design. Diagnosis according to the ICD-10. Thirty institutionalized women were evaluated using the WAIS on three separate occasions (in 1981, 1997, and 2012). The data were analyzed using a repeated measures split-plot method. Results: Patients scored one to two standard deviations below the average on the WAIS. At all three evaluation times, they scored consistently, significantly worse on Performance IQ scales than on Verbal IQ in the following sequence: Processing Speed (PS) < Perceptual Organization (PO) < Working Memory (WM) < Verbal Comprehension (VC). Longitudinally, there was a significant, linear average trend that was stable between the first and second assessments, with a significant drop in scores at the third evaluation on Performance IQ (η2 = .586) and Verbal IQ scales (η2 = .299). The same trend was observed in PS (η2 = .655) and WM (η2 = .438), while PO decreased across the three evaluations (η2 = .509) and no difference in VC was found (η2 = .126). Conclusion: Patients with schizophrenia presented with a low cognitive level. Longitudinally, they had a stable, differential profile of WAIS factors until late life, when performance dropped significantly.
We examined the effect of a tidal-mixing front on the three-dimensional distribution of larval fish habitats (LFHs) in the Midriff Archipelago Region in the Gulf of California during winter. Zooplankton and environmental variables were sampled from 0 to 200 m in 50 m strata. Four LFHs were defined in association with the front, two on the northern side and two on the southern side. The northern LFHs were: (1) the Mainland Shelf Habitat, located from the surface to 100 m depth on the north-east mainland shelf, characterized mainly by the presence of Citharichtys fragilis; and (2) the Wide Distribution Habitat, extending from north-west to south across the front from the surface to 200 m depth, dominated by the ubiquitous Engraulis mordax. The southern LFHs were: (3) the Eddy Zone Habitat, defined nearly on an anticyclonic eddy, with the highest larval abundance and richness from the surface to 100 m depth, dominated by Leuroglossus stilbius; and (4) the Southern Gulf Habitat, associated with low temperature waters from the southern Gulf of California, dominated by southern-gulf species (e.g. Scomber japonicus and Sardinops sagax). Despite the weak stratification and low thermal contrast (~1.5°C) across the south front compared to summer (~3°C), our results demonstrate that the frontal zone may influence the formation of planktonic habitats even during generally homogeneous periods, which may also be relevant in other regions of the world.
Beyond academic vocabulary, the constellation of skills that comprise academic language proficiency has remained imprecisely defined. This study proposes an expanded operationalization of this construct referred to as core academic language skills (CALS). CALS refers to the knowledge and deployment of a repertoire of language forms and functions that co-occur with school learning tasks across disciplines. Using an innovative instrument, we explored CALS in a cross-sectional sample of 235 students in Grades 4–8. The results revealed between- and within-grade variability in CALS. Psychometric analyses yielded strong reliability and supported the presence of a single CALS factor, which was found to be predictive of reading comprehension. Our findings suggest that the CALS construct and instrument appear promising for exploring students’ school-relevant language skills.
At the present time, no material is known that is completely inert to chemical or biochemical action and immune to weathering damage. Concrete is no exception, but, under what might be considered normal exposure conditions, it has a very long life. Concrete made by the Romans from natural cement is in excellent condition after more than 2000 years of service. The controversies generated by contradictory expert testimonies in several lawsuits involving sulfate attack on concrete, and by the large numbers of recently published papers containing data on the subject, have caused considerable anxiety about sulfate attack mechanisms and the service life of concrete structures. Furthermore, frequently the physical attack by salt crystallization is being confused with the classical sulfate attack, which involves the chemical interaction between sulfate ions from an external source and the constituents of cement paste. In addition, there is also an internal sulfate attack –a chemical attack in which the source of sulfate ions resides in the concrete aggregates or cement–. Additionally, modern concrete as been affected by the products of microorganism metabolism, in particular sulfuric acid, this damage done to hardened concrete is known as concrete biodeterioration and also known as microbiologically induced corrosion of concrete (MICC). Being perhaps this biodeterioration the most important cause of concrete decay and perhaps the true explanation of sulfate attack on concrete. Some of the controversies about sulfate attack are addressed in this article, we have studied the case applying simple considerations concerning concrete composition and flouting at the same time some of the stricter observed paradigms in the cement and concrete industry. It is concluded that a holistic approach is necessary to separate the real causes of sulfate attack on concrete from the imaginary ones.
The effectiveness of lightweight aggregate (LWA) as an internal curing agent (ICA) to reduce concrete shrinkage is evaluated for repair concrete used in cultural heritage works (RCCHW) using curing periods of 30 days. Normal weight aggregate is replaced by LWA at volume replacement levels ranging from 10 to 14%. The mixtures contain Portland cement maintaining the paste content at approximately 24.1% of concrete volume. Comparisons are made with mixtures containing low-absorption granite and high-absorption limestone normal weight coarse aggregates. At the replacement levels used in this study, LWA results in a small reduction in concrete density, no appreciable effect on concrete compressive strength, and a decrease in concrete shrinkage for drying periods up to 30 days. With a curing period of 14 days, all mixtures with LWA exhibited less shrinkage than the mixtures with either low- or high-absorption normal weight aggregates.
The objective of this study was to elucidate the signalling pathways initiated by cAMP once inside the Xenopus laevis oocyte, where it triggers and maintains vitellogenin endocytic uptake. Our results showed the presence of Xepac transcripts at all stages of oogenesis and we demonstrated that a cAMP analogue that exclusively activates Xepac, 8-CPT, was able to rescue the endocytic activity in oocytes with uncoupled gap junctions. Inhibition experiments for the IP3/Ca2+ signalling pathway showed either a complete inhibition or a significant reduction of the vitellogenic process. These results were confirmed with the rescue capability of the A-23187 ionophore in those oocyte batches in which the IP3/Ca2+ pathway was inhibited. Taking our findings into account, we propose that the cAMP molecule binds Xepac protein enabling it to activate the IP3/Ca2+ pathway, which is necessary to start and maintain X. laevis vitellogenin uptake.
This work covers the design of stimuli-responsive membranes and their ever-expanding range of use. Stimuli-responsive membranes that change their physicochemical properties in response to changes in their environment were synthesized for biomedical application. Responsive cotton-g-[2-(dimethylamino) ethyl methacrylate] membranes were obtained using γ-rays by mutual irradiation (direct method). The effect of absorbed dose, dose rate, and monomer concentration on the grafting yield was determined. The grafted samples were verified by the FTIR-ATR, 1H and 13C HRMAS NMR and 13C CPMAS NMR spectroscopies; thermal properties were analyzed by TGA and DSC and the stimuli-responsive behavior was studied by DSC.
Sulfate attack on concrete has been studied worldwide for more than 60 years. However, the mechanisms of attack are still not entirely understood, and deterioration of concrete from sulfates still occurs. The source of the sulfates may be either external or internal. External sources are the naturally occurring sulfates in the environment or those sulfates that are the product of industrial processes or various human activities (e.g. fertilizers often release sulfates into the soil and groundwater). Internal sources of sulfates may include the sulfates introduced in the cements from which concrete is made. The purpose of this study is to find out the amount of sulfates that concrete can withstand in the water. Standards tests have been developed to evaluate the resistance of concretes to sulfate attack. Some, but not all of these tests, take into account the mechanisms of sulfate attack so far discovered in research work. The tests range from those that monitor changes in the strength of concrete specimens after set periods of immersion in known compositions sulfate solutions, to those that use x- ray diffraction to examine concrete specimens for expansive products (e.g. ettringite and thaumasite) that have resulted from sulfate attack.
This article examines changes in ritual practices during the Epiclassic period in central Mexico. It presents data recovered from recent excavations of a shrine discovered in Lake Xaltocan in the northern Basin of Mexico. Pottery and AMS dates place the construction and use of the shrine in the Epiclassic period. The shrine was first built during or soon after the collapse of the Teotihuacan state. With the decline of Teotihuacan and the emergence of competing centers, ritual practitioners began human sacrifice: the remains of over 30 individuals were documented, including 13 complete severed crania. This practice suggests conflict as the political landscape became decentralized. Despite how broader processes may have affected behavior, the shrine, ritual practice was fundamentally local. We present archaeobotanical evidence of offerings of food, incense, and flowers that elucidates the microlevel nature of ritual at the shrine.
The damage that the products of microorganism metabolism, in particular biogenic sulfuric acid, do to hardened concrete is known as concrete biodeterioration. These microorganisms, Acidithiobacillus thiooxidans, Acidithiobacillus ferrooxidans and sulfate-reducing bacteria (SRB) are ubiquitous in the environment and they produce either hydrogen sulfide or sulfuric acid that can dissolve and disintegrate the concrete matrix. Their activity plays a very important function in the whole spectrum of degradation processes such as corrosion of reinforced metals and concrete.
In Canada and in the northern part of the United States, concrete structure failures from concrete biodeterioration are less common than in the southern part of the United States and in Mexico, nevertheless, it is a serious and expensive problem in hydraulic structures and sewage collection systems, which rapidly deteriorate. Also, leaking sewage systems result in the loss of groundwater resources particularly important in this arid region. Almost every city in the Mexican-American border region, who’s combined population is more than 15 million people, faces this problem. The U.S. cities have made some provision to face these concrete structure problems, but the Mexican cities have made less effort. Additives and admixtures are used to improve the properties of the concrete; nonetheless, we have exposed here the importance of the factual composition of the Portland cement and concrete to mitigate concrete biodeterioration in the hydraulic structures and sewage collection systems.
This study examined the relationship between medical advice to engage in physical activity with type of demand required by physical activity and demographic variables. A cross-sectional study was developed, featuring a questionnaire on physicians’ advice, and type of demand. The questionnaire was completed by a probability and nationwide sample of older adults in Spain (n = 933, M = 74.1, range 65–93), randomly selected using multistage sampling. More physically active older adults have, more often than the less active, received physicians’ advice to engage in physical activity. There is a significant relationship between medical advice and type of demand (p < .01) and age (p < .05). However, no relationship was found between physician medical advice and gender, social class, or income. Physicians can effectively promote physical activity among sedentary older adults through appropriate advice. Consequently, health authorities should promote physicians’ advising older patients to pursue physical activity.
Relapses in cocaine abusers in treatment are an important problem. The majority of patients are incapable of sustaining abstinence over any length of time. To identify the factors associated to relapses risk in the cocaine use can be an optimal choice to improve the treatment strategies. The aim of this study was to analyze relapse-risk factors in cocaine-dependent patients on treatment. Participants were 102 patients who had begun outpatient treatment at a public health center in Spain. Some functional areas and cocaine use are evaluated for a period of six months. A structural equations model was used to identify possible predictive variables. The results show that social-family environment and economic-employment situation were associated with greater risk of relapse. Likewise, the social-family environment was related to severity of addiction. It is concluded that the incorporation of family intervention strategies and vocational/employment counseling may help to reduce relapse rates in cocaine addicts receiving treatment.
Cancer patients receiving chemotherapy have a high risk of malnutrition secondary to the disease and treatment, and 40–80 % of cancer patients suffer from different degrees of malnutrition, depending on tumour subtype, location, staging and treatment strategy. Malnutrition in cancer patients affects the patient's overall condition, and it increases the number of complications, the adverse effects of chemotherapy and reduces the quality of life. The aim of the present study was to evaluate weight-loss prevalence depending on the tumour site and the gastrointestinal (GI) symptoms of oncology patients receiving chemotherapy. We included 191 cancer patients receiving chemotherapy. Files of all patients were reviewed to identify symptoms that might potentially influence weight loss. The nutritional status of all patients was also determined. The cancer sites in the patients were as follows: breast (31·9 %); non-colorectal GI (18·3 %); colorectal (10·4 %); lung (5·8 %); haematological (13·1 %); others (20·5 %). Of these patients, 58 % experienced some degree of weight loss, and its prevalence was higher among the non-colorectal GI and lung cancer patients. Common symptoms included nausea (59·6 %), anorexia (46 %) and constipation (31·9 %). A higher proportion of patients with ≥ 5 % weight loss experienced anorexia, nausea and vomiting (OR 9·5, 2·15 and 6·1, respectively). In conclusion, these results indicate that GI symptoms can influence weight loss in cancer patients, and they should be included in early nutritional evaluations.
Many migratory waterbird populations are in decline and loss of natural wetlands is one of the main causes. However, some species may respond positively to artificial wetland recreation. In Extremadura (south-west Europe), several large reservoirs were created for irrigation since the 1960s and some comparatively small reservoirs were built from the late 1990s onwards close to rice fields. Here we analyse the abundance of wintering dabbling ducks (Anas spp.) in Extremadura before (1991–1994) and after (2007–2010) the creation of these new reservoirs in order to address the current importance of the area for this guild within the East Atlantic Flyway (EAF). A mean of 25,277 dabbling ducks wintered in the study area during 1991–1994, increasing to 46,163 individuals during 2007–2010. After controlling for environmental variables, Northern Pintail Anas acuta, Common Teal A. crecca and Northern Shoveler A. clypeata experienced significant increases in the area between both periods, and only Eurasian Wigeon A. penelope suffered a significant decrease. Mallard A. platyrhynchos and Gadwall A. strepera populations did not show any significant trend. The large older reservoirs experienced overall population decreases between the two periods, with four new reservoirs holding more than 35,000 wintering dabbling ducks. Our results reflect an overall improvement in habitat conditions, driven by the creation of reservoirs near to rice fields that could have resulted in a partial redistribution of wintering dabbling ducks in the EAF. The area emerges as one of the most important wintering sites for dabbling ducks in southern Europe, regularly exceeding two of the Ramsar Convention criteria for the conservation of several populations. The protection of these new reservoirs by legal mechanisms would guarantee the existence of a large functional wetland area, which could also mitigate the loss of natural wetlands for populations using the EAF.
The aim of the present study was to show the participation and physiological role of calmodulin (CaM) and cAMP during vitellogenin endocytic uptake in the amphibian Xenopus laevis. The results showed a differential distribution of CaM in the ovary follicles during oogenesis. The CaM intracellular localization was not affected by gap junction's downregulation and CaM inhibition did not completely abolished the endocytic activity of oocytes. We showed that cAMP was able to completely rescue the endocytic competence in follicles in which gap junctional communication had been disrupted by octanol. Moreover cAMP was capable of restoring oocyte endocytic capability in the presence of octanol and stelazine, a CaM inhibitor. We propose that, in Vtg uptake regulation, cAMP is upstream of CaM during the endocytic signalling pathway.
The spatial distribution of the subtidal crustacean assemblages of the Guadiana River
estuary was studied previous to the building of the Alqueva Dam (the biggest dam in
Europe). The differences between an estuarine and marine environment seem to be the main
reason responsible for the composition and distribution of the crustaceans along the study
zone. The Guadiana estuary has shown high number of species in comparison with other
nearby estuaries and this richness seems justified by the scarce influence of pollutants
(most of them have shown low or moderate values) and their hydrodynamic and granulometric
characteristics (76 species were found, 39 in the estuarine area). A gradient of
enrichment and structuring of the assemblages was shown from the upstream to the marine
zones and a spatial segregation of species was found along this estuarine environmental
gradient, e.g. the amphipod Corophium multisetosum and the isopod
Cyathura carinata in the upper estuary; the amphipod
Bathyporeia cf. pilosa and the isopods
Lekanesphera levii and Saduriella losadoi in the
middle estuary; the amphipod Melita hergensis in the mouth; and a high
number of species in the marine area. Since the Alqueva Dam will reduce the river
discharges and may cause changes in the abiotic characteristics such as granulometry of
sediments or salinity, this study establishes a baseline against which a monitoring
programme or follow-up studies could measure any significant effects of the dam or related