Effects of chromium (Cr) and zinc (Zn) supplementation on metabolism, inflammation, and production parameters in heat-stressed and nutrient-restricted pigs

Heat stress (HS) adversely impacts all aspects of global agriculture, and it particularly constrains domestic animal productivity and compromises animal welfare. Heat-stressed animals employ physiologic and metabolic adjustments to ameliorate the heat insult; consequently, efficiency is compromised because nutrients are partly diverted away from production purposes to maintain euthermia. Reduced animal productivity during HS can also be attributed to the direct effects of HS (independent of nutrient intake) on metabolism, physiology, reproduction, and health. Therefore, identifying nutritional alternatives with the potential to ameliorate the detrimental effects of HS on economically important performance and health is of particular interest. The overall thesis objectives were to investigate the dietary effects of chromium (Cr) and zinc (Zn) supplementation in heat-stressed and nutrient-restricted pigs. In the first study (Chapter 2), finishing pigs were used in a replicated experiment to evaluate the effects of Cr propionate supplementation on growth performance and metabolism during HS. As expected, pigs exposed to HS had increased thermal indices and decreased growth performance. However, Cr supplementation tended to increase average daily gain in chronically heat-stressed pigs. Regardless of environmental treatments, pigs supplemented with Cr had numerically increased feed intake. Further, adding Cr to the HS pig diet increased circulating neutrophils and monocytes. The second study (Chapter 3) evaluated the effects of Zn amino acid complex on metabolism, leaky gut biomarkers, and inflammation during and following HS. Pigs exposed to HS had increased body temperature and respiration rates as well as reduced production metrics. Despite marked reductions in feed intake, circulating insulin increased during HS and remained increased during thermal neutral recovery. Interestingly, supplemental Zn tended to decrease plasma tumor necrosis factor alpha (TNFα) levels before and after HS exposure. However, no effects of dietary Zn were observed on production parameters or other blood metabolites. In conclusion, both experiments demonstrated that HS adversely impacts animal productivity and health. Results suggest that Cr supplementation might be beneficial on growth performance and health during HS. Additionally, Zn supplementation might be advantageous at reducing basal inflammation. Altogether, these findings suggest that dietary interventions aimed at alleviating the negative consequences of HS are plausible. However, additional research is needed to better understand the biology and mode of action of both Cr and Zn supplementation during HS

Group delay in THz spectroscopy with ultra-wideband log-spiral antennae

We report on the group delay observed in continuous-wave terahertz spectroscopy based on photomixing with phase-sensitive homodyne detection. We discuss the different contributions of the experimental setup to the phase difference \Delta\phi(\nu) between transmitter arm and receiver arm. A simple model based on three contributions yields a quantitative description of the overall behavior of \Delta\phi(\nu). Firstly, the optical path-length difference gives rise to a term linear in frequency. Secondly, the ultra-wideband log-spiral antennae effectively radiate and receive in a frequency-dependent active region, which in the most simple model is an annular area with a circumference equal to the wavelength. The corresponding term changes by roughly 6 pi between 100 GHz and 1 THz. The third contribution stems from the photomixer impedance. In contrast, the derivative (d\Delta\phi / d\nu) is dominated by the contribution of periodic modulations of \Delta\phi(\nu) caused by standing waves, e.g., in the photomixers' Si lenses. Furthermore, we discuss the Fourier-transformed spectra, which are equivalent to the waveform in a time-domain experiment. In the time domain, the group delay introduced by the log-spiral antennae gives rise to strongly chirped signals, in which low frequencies are delayed. Correcting for the contributions of antennae and photomixers yields sharp peaks or "pulses" and thus facilitates a time-domain-like analysis of our continuous-wave data.Comment: 7 pages, 7 figure

Donor-acceptor polymers for applications in organic electronics and photovoltaics

We have synthesized a new series of high-mobility polymeric semiconductors with good processability and excellent environmental stability for organic electronics and photovoltaics. Using these materials, solar cells were fabricated with power conversion efficiencies of up to 8.7% and remarkable fill factors of 76-80%.MINECO, Junta de Andalucí

How much dark matter is there inside early-type galaxies?

We study the luminous mass as a function of the dynamical mass inside the effective radius (r_e) of early-type galaxies (ETGs) to search for differences between these masses. We assume Newtonian dynamics and that any difference between these masses is due to the presence of dark matter. We use several samples of ETGs -ranging from 19 000 to 98 000 objects- from the ninth data release of the Sloan Digital Sky Survey. We perform Monte Carlo (MC) simulations of galaxy samples and compare them with real samples. The main results are: i) MC simulations show that the distribution of the dynamical vs. luminous mass depends on the mass range where the ETGs are distributed (geometric effect). This dependence is caused by selection effects and intrinsic properties of the ETGs. ii) The amount of dark matter inside r_e is approximately 7% +- 22%. iii) This amount of dark matter is lower than the minimum estimate (10%) found in the literature and four times lower than the average (30%) of literature estimates. However, if we consider the associated error, our estimate is of the order of the literature average.Comment: 24 pages, 12 figures. MNRAS accepte