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Climate change is producing an increase on extreme weather events around the world such as flooding, drought and extreme ambient temperatures impacting animal production and animal welfare. At present, there is a lack of studies addressing the effects of climatic conditions associated with energy intake in finishing cattle in South American feed yards. Therefore, two experiments were conducted to assess the effects of environmental variables and level of metabolizable energy intake above maintenance requirements (MEI) on performance and carcass quality of steers. In each experiment (winter and summer), steers were fed with 1.85 or 2.72 times of their requirements of metabolizable energy of maintenance. A total of 24 crossbred steers per experiment were used and located in four pens (26.25 m2/head) equipped with a Calan Broadbent Feeding System. Animals were fed with the same diet within each season, varying the amount offered to adjust the MEI treatments. Mud depth, mud scores, tympanic temperature (TT), environmental variables, average daily gain, respiration rates and carcass characteristics plus three thermal comfort indices were collected. Data analysis considered a factorial arrangement (Season and MEI). In addition, a repeated measures analysis was performed for TT and respiration rate. Mean values of ambient temperature, solar radiation and comfort thermal indices were greater in the summer experiment as expected (P<0.005). The mean values of TT were higher in steers fed with higher MEI and also in the summer season. The average daily gain was greater during summer v. winter (1.10±0.11 v. 0.36±0.06) kg/day, also when steers were fed 2.72 v. 1.85 MEI level (0.89±0.12 v. 0.57±0.10) kg/day. In summer, respiration rate increased in 41.2% in the afternoon. In winter, muddy conditions increased with time of feeding, whereas wind speed and rainfall had significant effects on TT and average daily gain. We conclude that MEI and environmental variables have direct effects on the physiology and performance of steers, including TT and average daily gain, particularly during the winter. In addition, carcass characteristics were affected by season but not by the level of MEI. Finally, due to the high variability of data as well as the small number of animals assessed in these experiments, more studies on carcass characteristics under similar conditions are required.
Roman bronze coins from the 3rd and 4th century AD exhibit a wide variety of chemistries on their surfaces. This variation has been attributed to the variable methods used to produce the coins, a large number of mints producing bronze currency, and the periods of currency devaluation within the Roman Empire. Besides the base bronze metallurgy (Cu,Sn), Ag, Pb, and Zn were frequently used as coinage metals. Silver coatings were often applied to increase the apparent value of the coins. Over the centuries these surfaces corroded producing a range of patinas. Non-destructive X-ray diffraction and X-ray fluorescence methods were used to evaluate ancient bronze coins. These methods are limited by their half depth of penetration into the coins, so the focus was on the chemistry of the patina's and how they related to the current appearance. Several 3rd-century bronze coins exhibited a very dark patina that was often composed of CuCl, Cu2O (cuprite) and several forms of copper hydroxyl chloride, resulting from surface deterioration caused by corrosion and is often referred to as bronze disease. Coins of the latter 3rd century and 4th century often exhibit patinas that are corrosion products of lead, silver, and tin, as lead and tin preferentially oxidize relative to the bronze alloys.
Using the liquid phase epitaxy technique (LPE) Ga0.86In0.14As0.13Sb0.87 layers lattice-matched to (100) Te-GaSb have been deposited, which were intentionally doped with Te and Zn in a wide range. The Raman spectra show that the layers become more defective as the dopant molar fraction is increased. Two main vibrational bands are observed in the Raman spectra centred at 230 and 245 cm-1 that depend strongly on the Te (Zn) molar concentration, which are assigned to the vibrational modes GaAs-like and to (GaSb+InAs)-like mixture. The low-temperature photoluminescence of n (p)-type GaInAsSb was obtained as a function of Te (Zn) concentration added to the melt solution. The photoluminescence was interpreted taking into account nonparabolicity of the conduction (valence) band. It is shown that the band-to-band radiative transition energy can be used to estimate the free carrier concentration in GaInAsSb, for a wide range of doping concentration.
The evolution of massive stars encompasses short-lived transition phases in which mass-loss is more enhanced and usually eruptive. A complex environment, combining atomic, molecular and dust regions, is formed around these stars. In particular, the circumstellar environment of B[e] Supergiants is not well understood. To address that, we have initiated a campaign to investigate their environments for a sample of Galactic and Magellanic Cloud sources. Using high-resolution optical and near-infrared spectra (MPG-ESO/FEROS, GEMINI/Phoenix and VLT/CRIRES, respectively), we examine a set of emission features ([OI], [CaII], CO bandheads) to trace the physical conditions and kinematics in their formation regions. We find that the B[e] Supergiants are surrounded by a series of rings of different temperatures and densities, a probable result of previous mass-loss events. In many cases the CO forms very close to the star, while we notice also an alternate mixing of densities and temperatures (which give rise to the different emission features) along the equatorial plane.
We present a tool for analysis and fit of stellar spectra using a mega database of 15,000 atmosphere models for OB stars. We have developed software tools, which allow us to find the model that best fits to an observed spectrum, comparing equivalent widths and line ratios in the observed spectrum with all models of the database. We use the Hα, Hβ, Hγ, and Hδ lines as criterion of stellar gravity and ratios of He II λ4541/He I λ4471, He II λ4200/(He I+He II λ4026), He II λ4541/He I λ4387, and He II λ4200/He I λ4144 as criterion of Teff.
V923 Aquilae (HD 183656) is a Be star which shows emission in Hα, cyclic V/R variations and variations in the near infrared region. This star displays a shell spectrum recognized by Harper(1937) and Bidelman (1950) who both remarked the presence of shell H lines, strong Fe II lines and variable radial velocity. Koubský et al. (1989) proposed V923 Aquilae to be a spectroscopy binary with an orbital period of 214.756 days and a semi-amplitude of 6.2 km/s. Iliev et al. (1994) found a correlation between the changes of the Balmer progression and the asymmetries of the Balmer lines with the orbital phase, considering the period calculated by Koubský.
The crayfish Cherax quadricarinatus stores calcium ions, easily mobilizable after molting, for calcifying parts of the new exoskeleton. They are chiefly stored as amorphous calcium carbonate (ACC) during each premolt in a pair of gastroliths synthesized in the stomach wall. How calcium carbonate is stabilized in the amorphous state in such a biocomposite remains speculative. The knowledge of the microstructure at the nanometer level obtained by field emission scanning electron microscopy and atomic force microscopy combined with scanning electron microscopy energy-dispersive X-ray spectroscopy, micro-Raman and X-ray absorption near edge structure spectroscopy gave relevant information on the elaboration of such an ACC-stabilized biomineral. We observed nanogranules distributed along chitin-protein fibers and the aggregation of granules in thin layers. AFM confirmed the nanolevel structure, showing granules probably surrounded by an organic layer and also revealing a second level of aggregation as described for other crystalline biominerals. Raman analyses showed the presence of ACC, amorphous calcium phosphate, and calcite. Elemental analyses confirmed the presence of elements like Fe, Na, Mg, P, and S. P and S are heterogeneously distributed. P is present in both the mineral and organic phases of gastroliths. S seems present as sulfate (probably as sulfated sugars), sulfonate, sulfite, and sulfoxide groups and, in a lesser extent, as sulfur-containing amino acids.
Including a multi-year collection of samples (2004–2011) the present research fills 20 years of an information gap regarding the PCB burden in south-west Atlantic franciscana dolphins (Pontoporia blainvillei) while aiming to test the null hypothesis that PCBs congeners are increasingly bioaccumulating in south-west Atlantic specimens in relation to northern hemisphere records. In addition, the present survey analyses indicators of potential biological impairment associated to PCBs tissue burden. The results could associate each sampling area group of dolphins to one or two Aroclor® patterns and point to dominant regional diffuse sources entering PCBs mixtures to the marine environment with a possible regional/long-range atmospheric contribution. In addition, total PCB levels were from four to seven times lower than the closer precedents for the area (18–26 years ago) indicating a progress in the environmental release and biota exposure of PCBs and posing an objective indicator of success of the present international elimination programme. Further, when compared with regional and global bioaccumulation patterns, PCBs congeners in Argentinean specimens appeared to occur in a decreasing tendency. Finally, calculated TEQs TCDD levels raised a concern in regards to environmental safety, showing guideline values to be widely exceeded and the occasional occurrence of positive correlations between PCBs bioaccumulation vs. sexual immaturity.
Poly(vinyl alcohol) (PVA) is a synthetic polymer which has been used in a wide variety of applications. This polymer has been extensively investigated by a large number of techniques to shed light about its physical and chemical properties. In this work, for fist time, high frequency (1x109-3x109 Hz) relaxation process has been observed in the PVA films in the temperature range of -100C to +1200C. This relaxation exhibits negative activation energy below glass transition temperature Tg and at higher temperature positive activation energy with subsequent saturation. Upon cooling the activation energy was negative again. This high frequency relaxation process and its temperature dependence can be attributed to the interaction of the bounded water and the changes of energy and freedom of movement of OH side molecular chains groups. This conclusion has been supported by in situ FTIR measurements. A possible scenario of this relaxation and dynamics of molecular motion has been proposed.
In fish, in vitro fertilization is an important reproductive tool used as first step for application of others biotechniques as chromosome and embryo manipulation. In this study, we aimed to optimize gamete quality and their short-term storage from the yellowtail tetra Astyanax altiparanae, for future application in laboratory studies. Working with sperm, we evaluated the effects of spawning inducers (carp pituitary gland and Ovopel® [(D-Ala6, Pro9-NEt) – mGnRH+metoclopramide]) and the presence of female on sperm motility. Additionally, we developed new procedures for short-term storage of sperm and oocytes. Briefly, sperm motility was higher when male fish were treated with carp pituitary gland (73.1±4.0%) or Ovopel® (79.5±5.5%) when compared with the control group treated with 0.9% NaCl (55.6±27.2%; P=0.1598). Maintenance of male fish with an ovulating female fish also improved sperm motility (74.4±7.4%) when compared with untreated male fish (42.1±26.1%; P=0.0018). Storage of sperm was optimized in modified Ringer solution, in which the sperm was kept motile for 18 days at 2.5°C. The addition of antibiotics or oxygen decreased sperm motility, but partial change of supernatant and the combination of those conditions improve storage ability of sperm. Fertilization ability of oocytes decreased significantly after storage for 30, 60 90 and 120 min at 5, 10, 15 and 20°C when compared with fresh oocytes (P=0.0471), but considering only the stored samples, the optimum temperature was 15°C. Those data describe new approaches to improve semen quality and gametes short-term storage in yellowtail tetra A. altiparanae and open new possibilities in vitro fertilization.
To prepare cholesteric liquid crystalline nonlinear optical materials with ability to be vitrified on cooling and form long time stability cholesteric glasses at room temperature, a series of platinum acetylide complexes modified with cholesterol has been synthesized. The materials synthesized have the formula trans-Pt(PR3)(cholesterol (3 or 4)-ethynyl benzoate)(1-ethynyl-4-X-benzene), where R = Et, Bu or Oct and X = H, F, OCH3 and CN. A cholesteric liquid crystal phase was observed in the complexes R = Et, and X = F, OCH3 and CN but not in any of the other complexes. When X = CN, a cholesteric glass was observed at room temperature which remained stable up to 130 °C, then converted to a mixed crystalline/cholesteric phase and completely melted to an isotropic phase at 230 °C. When X = F or OCH3 the complexes were crystalline at room temperature with conversion to the cholesteric phase upon heating to 190 and 230 °C, respectively. In the series X = CN, OCH3 and F, the cholesteric pitch was determined to be 1.7, 3.4 and 9.0 µ, respectively.
Illegal exploitation of resources is a cause of environmental degradation worldwide. The effectiveness of conservation initiatives such as marine protected areas relies on users' compliance with regulations. Although compliance can be motivated by social norms (e.g. peer pressure and legitimacy), some enforcement is commonly necessary. Enforcement is expensive, particularly in areas far from land, but costs can be reduced by optimizing enforcement. We present a case study of how enforcement could be optimized at Cocos Island National Park, Costa Rica, an offshore protected area and World Heritage Site. By analysing patrol records we determined the spatial and temporal distribution of illegal fishing and its relationship to patrol effort. Illegal fishing was concentrated on a seamount within the Park and peaked during the third year-quarter, probably as a result of oceanographic conditions. The lunar cycle in conjunction with the time of year significantly influenced the occurrence of incursions. The predictability of illegal fishing in space and time facilitates the optimization of patrol effort. Repeat offenders are common in the Park and we suggest that unenforced regulations and weak governance are partly to blame. We provide recommendations for efficient distribution of patrol effort in space and time, establishing adequate governance and policy, and designing marine protected areas to improve compliance. Our methods and recommendations are applicable to other protected areas and managed natural resources.
We introduce a new approach for fabricating hollow microneedles using vertically-aligned carbon nanotubes (VA-CNTs) for rapid transdermal drug delivery. Here, we discuss the fabrication of the microneedles emphasizing the overall simplicity and flexibility of the method to allow for potential industrial application. By capitalizing on the nanoporosity of the CNT bundles, uncured polymer can be wicked into the needles ultimately creating a high strength composite of aligned nanotubes and polymer. Flow through the microneedles as well as in vitro penetration of the microneedles into swine skin is demonstrated. Furthermore, we present a trade study comparing the difficulty and complexity of the fabrication process of our CNT-polymer microneedles with other standard microneedle fabrication approaches.
Three-dimensional (3D) composites of hydroxyapatite, phosphorylated and/or nonphosphorylated chitosan and sulphonated methylsiloxane polymer (HA/P-CHI: CHI/ S-MSP) were prepared by solid-liquid phase separation and solvent sublimation method. The HA, P-CHI and S-MSP were synthesized by chemical continuous wet-calcination, phosphorylation reaction and hydrosilylation-sulphonation reactions, respectively. 3D composites were analyzed by scanning electron microscopy (SEM). Swelling ability, stability and formation of HA particles on the composites immersed in simulated body fluid (SBF) were analyzed. Osteoblasts showed high viability when cultured on composite scaffolds. 3D composites were not degraded after 8 weeks of subcutaneous implantation in rats.
Natural composite bioceramics such as bone, teeth, carapaces and shells contain organic and inorganic moieties, with the organic matrix components directly involved in the precise formation of these structures. We have previously shown that chicken eggshell contains two main sulfated polymers (proteoglycans), referred to as mammillan and ovoglycan which are involved in nucleation and growth of the eggshell calcite crystals. They differ on their anionic properties due to the carboxylate and sulfate content of their glycosaminoglycan component. Based on biological and biochemical evidences, the putative role of mammillan, a keratan sulfate proteoglycan, is in the nucleation of the first calcite crystals, while that of ovoglycan, a dermatan sulfate proteoglycan, is to regulate the growth and orientation of the later forming crystals of the chicken eggshell. In this communication, a systematic study of the influence of variable concentrations of glycosaminoglycans differing in their sulfation status on the morphology, size and number of calcium carbonate crystals after crystallization on microbridges from a calcium chloride solution under an atmosphere of ammonium carbonate at different pH is presented. Depending on the pH and concentration, the variation of sulfation status drastically changed the morphology, size and number of calcite crystals. The produced calcite particles with various morphologies are promising candidates for some novel materials with desirable shape- and texture-depending properties.
Graphene grown by Chemical Vapor Deposition (CVD) on nickel subsrate is oxidized by means of oxygen plasma and UV/Ozone treatments to introduce bandgap opening in graphene. The degree of band gap opening is proportional to the degree of oxidation on the graphene. This result is analyzed and confirmed by Scanning Tunnelling Microscopy/Spectroscopy and Raman spectroscopy measurements. Compared to conventional wet-oxidation methods, oxygen plasma and UV/Ozone treatments do not require harsh chemicals to perform, allow faster oxidation rates, and enable site-specific oxidation. These features make oxygen plasma and UV/Ozone treatments ideal candidates to be implemented in high-throughput fabrication of graphene-based microelectronics.
The avian eggshell is one of the most rapidly mineralizing biological systems known. By understandi'ng the key components and steps in this process, we hope to provide relevant information for fabrication of ceramic composites. The calcification of the eggshell occurs in three main steps: 1) fabrication of an organic matrix, 2) nucleation of an inorganic phase on the organic matrix, and 3) space-filling growth of the calcite phase. The different layers of an eggshell can be separately isolated and studied. Three approaches have been used in our study of the eggshell: 1) characterization of the organization and chemical composition of the shell, 2) selective removal or blocking of particular components to improve the remineralization of demineralized shells, and 3) addition of new components to produce composite ceramics of different kinds. In this preliminary communication, the organization of the shell matrix and membranes and their association with the crystal phase, the immunohistochemical occurrence and distribution of types I and X collagen, and of different proteoglycans are reviewed. Also the preliminary findings of the remineralization of the intact or modified eggshell are presented. These experiments allow us to identify the essential steps in forming a natural composite ceramic.
In this paper, CdO thin films are used for the first time as transparent anodes for organic light-emitting diodes (OLEDs). Highly conductive and transparent CdO thin films have been grown on glass and on single-crystal MgO(100) by low pressure metal-organic chemical vapor deposition (MOCVD) at 400°C, and were implemented in small-molecule OLED fabrication. Device response and applications potential have been investigated and compared with those of commercial ITO-based control devices. It is found that as-deposited CdO thin films are capable of injecting holes into such devices, rendering them promising anode materials for OLEDs. A maximum luminance of 32,000 cd/m2 and an external forward quantum efficiency of 1.4 %, with a turn-on voltage of 3.2 V are achieved on MgO(100)/CdO-based devices.