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In this paper, a general solution to the formation control problem without collisions for first-order multi-agent systems is proposed. The case of an arbitrary number of mobile agents on a plane with saturated input velocity is analysed. Besides, conditions on the communication graph among agents are relaxed to the only requirement of containing a directed spanning tree. This general approach is an extended result from the simpler case of combinations of cyclic pursuit communication graphs. The proposed solution to this problem is designed in two steps. First, the asymptotic convergence in the absence of collisions is ensured. After this, the non-collision problem is faced by analysing the most general possible geometrical scenario which can lead to collision among agents. Discontinuous vector fields with unstable counterclockwise focus behaviour are applied by every agent in order to repel each other. Numerical simulations illustrate the performance of the proposed scheme.
This research communication addresses the hypothesis that in dual-purpose goats, exposure to 1 h of extra-light given from 16 to 17 h after dawn (pulse of light) in winter stimulates milk yield. One group of goats was maintained under natural short photoperiod (natural day; ND (n = 7)). Another group of lactating females was submitted to an artificial long-day photoperiod consisting of 16 h light and 8 h darkness (long days; LD (n = 7)). A third group of females received one single hour of extra-light 16 h after the fixed dawn (pulse of light; PL (n = 6)). Goats from LD and PL yielded 30% more milk than goats from ND. Mean percentages of fat, protein and lactose contents in milk did not differ between the 3 groups at any stage of lactation, but these components in grams/day were higher in goats from PL than in the others two groups within the first 45 d of lactation. In conclusion, dual-purpose lactating goats that started their lactation during natural short days, the daily exposition to a 1-h pulse of light is sufficient to stimulate milk yield compared to females maintained under natural short photoperiod.
This study analyzes the relationship between the two intrapersonal perfectionism dimensions (i.e., Self-Oriented Perfectionism-Critical, SOP-C, and Self-Oriented Perfectionism-Strivings, SOP-S) and the components of aggressive behavior (cognitive, emotional and motor) in a sample of 804 (48.3% females) Spanish students between the ages of 8 and 11 (M = 9.57; DE = 1.12). The Spanish versions of the SOP-C and SOP-S subscales of the Child/Adolescent Perfectionism Scale and the Aggression Questionnaire were used. Students with high SOP-C scored significantly higher (p < .001) than their peers with low SOP-C on all components of aggressive behavior. The magnitude of these differences (Cohen’s d index) ranged from .40 to .59. In contrast, non-significant statistical differences were found between students with high and low SOP-S. Moreover, logistic regression analysis revealed that SOP-C significantly and positively predicted high Hostility, Anger and Physical and Verbal Aggression, whereas none of these components were significantly predicted by SOP-S (95% CI). Results are discussed, taking into account the debate on the conceptualization and nature of intrapersonal perfectionism.
At a global level, dairy cow production systems (DCPS) are important sources of nourishment and profits, but they generate environmental impacts such as overexploitation of different resources including water, lands and fossil energy. Quantification of water and carbon footprint to define mitigation strategies and a more rational use of natural resources, is a reiterated claim. The aim of this study was to perform an economic evaluation of the environmental impact of the DCPS from the Comarca Lagunera, Mexico (24°N, 102°W, 220 mm, hot-semiarid climate) We contrasted the economic value (EV) generated by the DCPS with respect to the economic costs (EC) due to the greenhouse gas emissions (GHGE) and the water footprint (WFP) of this DCPS. While quantifications of GHGE considered those proposed by the Intergovernmental Panel on Climate Change, the WFP involved the use of blue, gray and green water by the DCPS and related activities. Quantification of the EC of WFP considered an international average price of water. In the year 2017, the Comarca Lagunera registered a dairy cow inventory of 493 144 heads, with 227 142 lactating cows, which produced 2386 million liters of milk per year with an annual average EV of €525.3 million. The EC (€, millions) generated by the GHGE and WFP were €311.8 and €11 980.7, respectively, with a total EC of € 12 292.5 million. When the EV of milk production and the total environmental EC are compared, the contrast demonstrates not only the noteworthy environmental impact but also the significant and senseless biological and EC. In addition, having a large dairy cow concentration creates pollution concerns and the DCPS transfers both nutrients and water resources from an ecologically vulnerable arid region. Therefore, some mitigation strategies such as, better cow genotype, feed and manure management combined with the production of forages and grains in a different geographical region are suggested to promote an optimum use of water in order to uphold the social, economic and biologic sustainability of the Comarca Lagunera, Mexico.
Composites from carbon nanotubes and polymers have been synthesized and studied. The composites were obtained joining carbon nanotubes with polymethyl methacrylate, nylon-6 and polystyrene. The materials were observed through scanning electron microscopy to evaluate the carbon nanotubes dispersion in the polymeric matrices. FTIR and Raman spectroscopies were used to analyze the interactions among functionalized and non-functionalized multiwalled carbon nanotubes and polymers, demonstrating affinity and peculiar spectra behaviors for each composite with different carbon nanotubes loads.
The pestiviruses bovine viral diarrhea virus 1 (BVDV-1), 2 (BVDV-2), and HoBi-like (HoBiPeV) are endemic among Brazilian cattle, the world's largest commercial bovine herd. In the last two decades (1998–2018) over 300 bovine pestiviruses have been partially or fully sequenced in Brazil, including viruses from different regions, different epidemiological backgrounds, and associated with diverse clinical presentations. Phylogenetic analysis of these viruses demonstrated a predominance of BVDV-1 (54.4%), with subgenotypes −1a (33.9% of total) and −1b (16.3%) being more frequent and subgenotypes −1d, −1e, and −1i at very low frequencies. The overall BVDV-2 frequency was 25.7% but it varied largely by region, reaching up to 48% in Southern states. BVDV-2b was the predominant subgenotype (84.8% of BVDV-2), followed by BVDV-2a (8.86%). HoBiPeV accounted for 19.9% (61/307) of the genotyped viruses and were detected at high frequency in cattle from Northeastern states. These findings demonstrate a unique mix of pestivirus species and subgenotypes, unlike that seen in Europe or North America. The design of effective diagnostic tools, vaccines, and control programs for limiting bovine pestivirus infections in Brazil must take into consideration this unique mix of viruses. This article provides a critical review of two decades of genetic identification of pestiviruses in Brazil.
Inclusion of legume in grass pastures optimizes protein values of the forage and promotes improved digestibility. Therefore, we hypothesized that finishing steers on a novel combination of legumes and grass pasture would produce carcasses with acceptable traits when compared to carcasses from steers finished in feedlot systems. In this study, we evaluated the effects of finishing steers on three systems including: grazing legume–grass pasture containing oats, ryegrass, white and red clover (PAST), grazing PAST plus supplementation with whole corn grain (14 g/kg BW (SUPP)), and on a feedlot-confined system with concentrate only (28 g/kg BW, consisting of 850 g/kg of whole corn grain and 150 g/kg of protein–mineral–vitamin supplement (GRAIN)) on growth performance of steers, carcass traits and digestive disorders. Eighteen steers were randomly assigned to one of three dietary treatments and finished for 91 days. Data regarding pasture and growth performance were collected during three different periods (0 to 28, 29 to 56 and 57 to 91 days). Subsequently, steers were harvested to evaluate carcass traits, presence of rumenitis, abomasitis and liver abscesses. The legume–grass pasture provided more than 19% dry matter of protein. In addition, pasture of paddocks where steers were assigned to SUPP and PAST treatments showed similar nutritional quality. When compared to PAST, finishing on SUPP increased total weight gain per hectare, stocking rate, daily and total weight gains. The increase of weight gain was high to GRAIN than SUPP and PAST. Steers finished on GRAIN had high hot carcass weight, fat thickness and marbling score when compared to PAST. However, these attributes did not differ between GRAIN and SUPP. Abomasum lesions were more prevalent in steers finished on GRAIN when compared to PAST. Results of this research showed that it is possible to produce carcasses with desirable market weight and fat thickness by finishing steers on legume–grass pasture containing oats, ryegrass, white and red clover. Moreover, supplementing steers with corn when grazing on legume–grass pasture produced similar carcass traits when compared to beef fed corn only.
This work presents the synthesis and characterization of TiO2 nanotubes (NTT) with chitosan (CS). In a first stage, electrochemical anodization of titanium foils was used to generate NTT in a membrane-type arrangement. From these experiments, suitable experimental conditions were selected. In a second stage, the synthesized NTT were detached from the titanium foils by sonication. In the third stage, the detached NTT were dispersed in an acid solution containing CS in various concentrations. Finally, the nanotubes-chitosan (NTT/CS) samples were characterized by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and Fourier Transform Infrared Spectrometry (FTIR). Our results showed that the NTT presented very regular tube morphology with -OH and Ti-O- functional groups on the surface. The interaction of NTT and chitosan was enhanced by increasing the time of contact during the synthesis of the titanium composites.
PA6 and PMMA polymers with different MWCNTs addition (5, 7 and 9 wt %) were synthetized through casting solution, resulting in improvement properties in contrast to pristine polymers. SEM images showed the MWCNTs embedded into polymeric matrices. D, G and G´ bands of MWCNTs were confirmed by Raman spectroscopy and functional groups observed in both nanocomposites by FTIR demonstrated a strong interaction. A significant increasing in electrical conductivity and microhardness was observed in all the nanocomposites. Major microhardness values were obtained in MWCNTs/PA6 (50 HV) however the MWCNTs/PMMA nanocomposites showed the highest electrical conductivity value (6.4×10-4 S/cm).
People with psychotic disorders face impairments in their global functioning and their quality of life (QoL). The relationship between the two outcomes has not been systematically investigated. Through a systematic review, we aim to explore the presence and extent of associations between global functioning and QoL and establish whether associations depend on the instruments employed.
In May 2016, ten electronic databases were searched using a two-phase process to identify articles in which associations between global functioning and QoL were assessed. Basic descriptive data and correlation coefficients between global functioning and QoL instruments were extracted, with the strength of the correlation assessed according to the specifications of Cohen 1988. Results were reported with reference to the Meta-analysis of Observational Studies in Epidemiology guidelines and PRISMA standards. A narrative synthesis was performed due to heterogeneity in methodological approaches.
Of an initial 15 183 non-duplicate articles identified, 756 were deemed potentially relevant, with 40 studies encompassing 42 articles included. Fourteen instruments for measuring global functioning and 22 instruments for measuring QoL were used. Twenty-nine articles reported linear associations while 19 assessed QoL predictors. Correlations between overall scores varied in strength, primarily dependent on the QoL instrument employed, and whether QoL was objectively or subjectively assessed. Correlations observed for objective QoL measures were consistently larger than those observed for subjective measures, as were correlations for an interviewer than self-assessed QoL. When correlations were assessed by domains of QoL, the highest correlations were found for social domains of QoL, for which most correlations were moderate or higher. Global functioning consistently predicted overall QoL as did depressive and negative symptoms.
This review is the first to explore the extent of associations between global functioning and QoL in people with psychotic disorders. We consistently found a positive association between global functioning and QoL. The strength of the association was dependent on the QoL instrument employed. QoL domains strongly associated with global functioning were highlighted. The review illustrates the extensive array of instruments used for the assessment of QoL and to a lesser extent global functioning in people with psychotic disorders and provides a framework to understand the different findings reported in the literature. The findings can also inform the future choice of instruments by researchers and/or clinicians. The observed associations reassure that interventions for improving global functioning will have a positive impact on the QoL of people living with a psychotic disorder.