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X-ray diffractometer studies of single-crystal quartz and orthoclase reveal the peak shock pressure experienced by the samples. This procedure may facilitate tapid, quantitative interpretation of the peak shock pressures experienced by materials occurring in lunar or terrestrial impact structures. Shocked specimens were obtained from the NASA 20 mm flat-plate accelerator at Johnson Space Center, Houston. Orthoclase single crystals were shocked normal to the (001) plane at pressure intervals between 0 and 297 kb. The amplitude of the 27.6° two-theta (002) maximum decreases as a function of increasing shock pressure. Quartz single crystals were shocked normal to the (0001) plane at pressure intervals between 0 and 310 kb. Examination of the peak amplitude/ half-width ratios for the 26.6° two-theta (101) and the 20.8° twotheta (100) reveals a general correlation of these ratios with shock pressure. This method seems appropriate for the calibration of shock pressures experienced by crystalline materials.
Intensive silvopastoral systems (ISS) are a sustainable alternative to monoculture systems (MS). The presence of trees and legumes improves animal welfare due to the increased food quality and quantity and the presence of shade while providing a variety of environmental services. As cattle behaviour is greatly affected by environmental conditions, knowledge on the behavioural trade-offs that cattle make to meet their demands while foraging in different grazing systems is important, as this will help us understand the perceived advantages of ISS. This pilot study assessed the behaviour of heifers in an ISS (n=8 heifers) and MS (n=8 heifers) in the Mexican tropics during the dry and rainy seasons, and its relationship with forage availability, mean travelled distance and the temperature humidity index (THI). In both seasons, daily foraging times were longer in the MS than the ISS (P<0.01). The duration of rumination was higher for ISS (P<0.01) and the duration of lying was higher for the dry season (P<0.05). The decrease in foraging times in relation to THI was significantly higher in the ISS than in the MS (mean slope±SE: ISS=−4.64±0.34; MS=−2.34±0.22; t=−14.20, P<0.001). The results suggest that the forage availability and access to shade in the ISS allow cattle to rest longer and increase rumination, whereas cattle in MS spend more time searching for food and foraging at times of the day were the temperatures were higher as a compensatory strategy, which potentially decreases cattle’s welfare and production qualities when compared with the ISS. In conclusion, ISS are likely to generate positive behavioural trade-offs that result in better welfare conditions and higher productive potential.
Symbiotic relationships are a common phenomenon among marine invertebrates, forming both obligatory and facultative dependencies with their host. Here, we investigate and compare the population structure of two crustacean species associated with both shallow and mesophotic ecosystems: an obligate symbiont barnacle (Ceratoconcha domingensis), of the coral Agaricia lamarcki and a meiobenthic, free-living harpacticoid copepod (Laophontella armata). Molecular analyses of the Cytochrome Oxidase Subunit I (COI) gene revealed no population structure between mesophotic and shallow barnacle populations within south-west Puerto Rico (ΦST = 0.0079, P = 0.33). The absence of population structure was expected due to the pelagic naupliar larvae of the barnacles and the connectivity patterns exhibited by the coral itself within the same region. Laophontella armata exhibited significant structure based on the mitochondrial COI gene between the mesophotic reef ecosystem of El Seco, Puerto Rico and mangrove sediments of Curaçao (ΦST = 0.2804, P = 0.0). The El Seco and Curaçao copepods shared three COI haplotypes despite the obligatory benthic development of harpacticoid copepods and the geographic distance between the two locations. Three other COI haplotypes from El Seco exhibited higher than expected (up to 7%) intra-species variability, potentially representing three new cryptic species of harpacticoid copepods or rare, deeply divergent lineages of L. armata. This result is evidence for the urgent need of a deeper investigation into the meiofauna diversity associated with mesophotic coral ecosystems (MCEs), arguably the most diverse metazoan component of MCEs.
The International Court of Justice (ICJ)’s 2016 judgments on the three
cases Obligations concerning negotiations relating to cessation of the
nuclear arms race and to nuclear disarmament show the omnipresence
of the dichotomy between form and substance in the Court's case-law.
Commentators and several dissenting judges have stressed that the judgments
represent a landmark in the sense that the Court has radically
departed from the consideration of flexible standards in applying
procedural rules to the determination of the issue of identification of a legal
dispute. In other words, it made form prevail over substance.
Zinc oxide thin films were prepared via the sol-gel spin-coating method with the use of a spin processor. The film’s annealing parameters were varied to study their impact on the final film morphology and electrical properties. Characterization of the structural properties of the samples was carried on a X-ray diffractometer (XRD) and scanning electron microscopy. Electrical characterization was obtained with the use of a four point probe. Optical characterization of the samples was carried on a UV-Vis-NIR Spectrophotometer. Samples annealed under a cover are observed to have a higher transmission percentage on the visible light range while having a very small grain size and small relative resistivity. Samples annealed under standard atmospheric conditions show a larger grain size and resistivity, and correlated to it, a smaller transmission percentage. Samples annealed under vacuum prove to have a much more reduced optical, electrical, and structural properties when compared to the rest of the samples.
Magnetic nanoparticles (MNPs) are a class of materials that can be manipulated under the influence of an external magnetic field. Thanks to the ability of the MNPs to be guided by an external magnetic field that is like "action at a distance", combined with their low cytotoxicity and the intrinsic penetrability of magnetic fields into human tissue, opens up many applications involving the transport and/or immobilization of biological entities [1, 2].
This work is focused on the synthesis of magnetite nanoparticles by varied methods, their functionalization with nickel tetrasulfonated phthalocyanine, and the corresponding physicochemical characterization and colloidal stability studies in biologically compatible media. The in vitro production of singlet oxygen by these nanoparticles through photochemical stimulation in ultraviolet and visible region was evaluated, resulting in 4.5 and 4 µM respectly to magnetite synthetized in the group. The increase reactive oxygen species concentration in the cellular environment can result in modification and damage of cellular components, and potentially, cell death and necrosis. Therefore, these materials offer the promise of revolutionary tools for photodynamic therapy and hyperthermia, which are attractive strategies for cancer therapy without systemic toxicity.
Silvopastoral systems can be a good alternative for sustainable livestock production because they can provide ecosystem services and improve animal welfare. Most farm animals live in groups and the social organization and interactions between individuals have an impact on their welfare. Therefore, the objective of this study was to describe and compare the social behaviour of cattle (Bos indicus×Bos taurus) in a silvopastoral system based on a high density of leucaena (Leucaena leucocephala) combined with guinea grass (Megathyrsus maximus), star grass (Cynodon nlemfuensis) and some trees; with a monoculture system with C. nlemfuensis, in the region of Merida, Yucatán. Eight heifers in each system were observed from 0730 to 1530 h each day for 12 consecutive days during the dry season and 12 consecutive days during the rainy season. The animals followed a rotation between three paddocks, remaining 4 days in each paddock. The vegetation was characterized in the paddocks of the silvopastoral system to estimate the average percentage of shade provided. To make a comparison between systems, we used a t test with group dispersion, and Mann–Whitney tests with the frequency of affiliative and agonistic behaviours. We assessed differences in linearity and stability of dominance hierarchies using Landau’s index and Dietz R-test, respectively. The distance of cows with respect to the centroid of the group was shorter, and non-agonistic behaviours were 62% more frequent in the intensive silvopastoral system than in the monoculture one. Heifers in the silvopastoral system had a more linear and non-random dominance hierarchy in both seasons (dry season: h’=0.964; rainy season: h’=0.988), than heifers in the monoculture system (dry season: h’=0.571, rainy season: h’=0.536). The dominance hierarchy in the silvopastoral system was more stable between seasons (R-test=0.779) than in the monoculture system (R-test=0.224). Our results provide the first evidence that heifers in the silvopastoral system maintain more stable social hierarchies and express more sociopositive behaviours, suggesting that animal welfare was enhanced.
The highlight of this work is the synthesis of copper sulfide nanocrystals by a simple one-pot colloidal process, and the study of its electrochemical, electrical and morphological properties. Nanocrystals of Cu1.8S of about 15-30 nm were obtained at a temperature of 240°C under an argon atmosphere. The colloidal solution of the nanocrystals was analyzed by cyclic voltammetry. Agreeing to the values of EOx and ERedvs. SCE, and the average of three samples the HOMO and LUMO levels are 6.16 and 4.27 eV, respectively, the calculated HOMO – LUMO (Eg) is 1.89 eV. The Eg value, differs of that value obtained from Kubelka-Munk equation (1.7 eV). The photocurrent vs. time results showed that the Cu1.8S/Cu junction is photosensitive and could be used as absorbing material. The morphology and the topography of the film were analyzed by SEM and AFM techniques. Irregular agglomeration of nanocrystals was observed and a roughness of about 194 nm.
The study of corrosion behavior of polyurethane/nanohydroxyapatite hybrid coating in aerated Hank solution at 25 °C by Potentiodinamic and Electrochemical Impedance techniques was realized. The nanohydroxyapatite (nHA) powders were synthesized by ultrasonic assisted co-precipitation wet chemical method and then mixed with pure polyurethane (PU) during the polymerization. Results were supported by SEM morphologic characterization. Results showed that good corrosion resistance of hybrid coating, showing small corrosion product layer formation. Corrosion mechanisms are affected by an increasing of polarization resistance, promoting decreasing in the corrosion rates. Diffusion of ionic species was the governing mechanism in the corrosion behavior of polyurethane/nanohydroxyapatite hybrid coating.
Electrodes made of single-walled carbon nanotubes (SWCNTs) chemically modified by a series of anthraquinone derivatives (AQ) have been prepared and characterized by cyclic voltammetry in 0.1M H2SO4, using the standard 3 electrode set-up and by Raman spectroscopy. It has been demonstrated that a AQ modified SWCNT electrode provided between 114 to 220% higher specific capacitance, compared to pristine SWCNT electrode, depending on the length of the spacer between SWCNT and AQ.
This study investigates possible circularity in mechanisms of change in participants of Master Your Mood (MYM), a cognitive-based, online intervention for young adults with depressive symptoms. A previous study showed that MYM effectively reduced depression and anxiety and strengthened mastery.
We randomized 244 participants with depressive symptoms into MYM or a wait-list control condition. We explored the circularity hypothesis by several analyses. Correlations were computed to determine the association between (change in) depression and anxiety. Path analysis mediation models were used to explore whether change in anxiety and mastery mediated the intervention effect on depression, whether depression and mastery mediated the effect on anxiety and whether depression and anxiety mediated the effect on mastery. We used linear regression to explore whether early changes in anxiety predicted later changes in depression, and whether early changes in depression predicted later changes in anxiety.
Co-morbidity between depression and anxiety was high (69.2%) and the association between depression and anxiety change was strong (r = 0.677, p < 0.01). Changes in anxiety and mastery mediated change in depression (mediation proportion 44%); changes in depression mediated change in anxiety (79%) and mastery (75%). We did not find an early change in anxiety predictive for a late change in depression, and vice versa.
This study appears to confirm the hypothesized circularity in the recovery process. We found high co-morbidity and strong correlation between depression and anxiety levels and bi-directional relationships between potential mediators and outcomes. Early anxiety change scores were not predictive of late depression change scores, and vice versa.
In this paper we study the density of states in n-type N,N’-ditridecylperylene-3,4,9,10-tetracarboxylic diimide organic semiconductor using two different methods. The first one is based on the temperature dependence of the channel conductance in field-effect transistors. The second one is based on the subgap optical absorption coefficient measured using the Photothermal Deflection Spectroscopy technique. Both techniques allow estimating the distribution of localized states in the band gap of the semiconductor.
Multiwalled carbon nanotube (MWCNT)/Nylon-6 nanohybrids were prepared by in situ polymerization under microwave irradiation. The effect of time and power of irradiation on the surface conductivity of the nanohybrid was studied. It was observed that the resistivity increases with irradiation time at low microwave power (200W). On the other hand, at high power (600W) an opposite behavior was observed. And at intermediate power (400W) the resistivity was independent of the irradiation time. Resistivity values range from 102 to 101 Ω/sq. This behavior was associated with the polymer nanocoating covering the surface of the carbon nanotubes.
Positron Beam Analysis was for the first time performed in combination with a four-point bending stage. Applications of this novel technique on PVD TiN (5 m thick), WC:H (2.5 m) and CrN (1.5 m m) layers on tool steel, low carbon steel and stainless steel substrates are discussed. It appeared from PBA results that for these systems the coatings did not fail by delamination during bending. SEM confirmed that there was no decohesion but instead, cracking of the coatings was observed. In order to weaken the interface and quantify adhesion properties we propose to induce blistering based on localised gas implantation.