Alternatives to formic acid as a grass silage additive under two contrasting ensilability conditions

peer-reviewedThe effects of formic acid and four alternative additives on silage fermentation, in-silo DM losses and aerobic stability were compared in an experiment using both difficultto- ensile (DIFF) and easier-to-ensile (EASI) herbages. Both were ensiled in laboratory silos with either no additive or following the application of formic acid (FA; 850 g/kg) at 3 mL/kg herbage, Add-SaFeR® (ATF1) and GrasAAT® (ATF2), both based on ammonium tetraformate, at 4 mL/kg herbage, an antimicrobial mixture (MIX; potassium formate, sodium disulfite and sodium benzoate) at 3 g/kg herbage, or Ecosyl (LAB; Lactobacillus plantarum) at 3 mL/kg herbage. There were four replicates per treatment and the silos were stored for 132 days. DIFF silage made without additive was poorly fermented. All additives increased the extent and improved the direction of DIFF silage fermentation, and reduced in-silo losses. However, MIX did not reduce butyric acid concentration and increased the extent of aerobic deterioration. LAB had a smaller effect on fermentation and in-silo losses than FA. With EASI silages, all additives restricted the extent of fermentation and improved fermentation quality, with the latter effect being smaller than for DIFF silages. LAB promoted a particularly homolactic fermentation but subsequently increased aerobic deterioration. In both DIFF and EASI silages additive treatment improved in vitro digestibility. It is concluded that only ATF1, ATF2 and MIX were as effective as FA at improving silage preservation and reducing in-silo losses with both DIFF and EASI herbages. However, ATF1 and ATF2 were superior in reducing the apparent extent of proteolysis and MIX was slightly less effective at reducing the activity of saccharolytic Clostridia

Effects of percentage of blockage and flameholder downstream counterbores on lean combustion limits of premixed, prevaporized propane-air mixture

Lean combustion limits were determined for a premixed prevaporized propane air mixture with flat plate flame stabilizers. Experiments were conducted in a constant area flame tube combustor utilizing flameholders of varying percentages of blockage and downstream counterbores. Combustor inlet air velocity at ambient conditions was varied from 4 to 9 meters per second. Flameholders with a center hole and four half holes surrounding it were tested with 63, 73, and 85 percent blockage and counterbore diameters of 112 and 125 percent of the thru hole diameter, in addition to the no counterbore configuration. Improved stability was obtained by using counterbore flameholders and higher percentages of blockage. Increases in mixture velocity caused the equivalence ratio at blowout to increase in all cases

Multiple path prediction for traffic scenes using LSTMs and mixture density models

This work presents an analysis of predicting multiple future paths of moving objects in traffic scenes by leveraging Long Short-Term Memory architectures (LSTMs) and Mixture Density Networks (MDNs) in a single-shot manner. Path prediction allows estimating the future positions of objects. This is useful in important applications such as security monitoring systems, Autonomous Driver Assistance Systems and assistive technologies. Normal approaches use observed positions (tracklets) of objects in video frames to predict their future paths as a sequence of position values. This can be treated as a time series. LSTMs have achieved good performance when dealing with time series. However, LSTMs have the limitation of only predicting a single path per tracklet. Path prediction is not a deterministic task and requires predicting with a level of uncertainty. Predicting multiple paths instead of a single one is therefore a more realistic manner of approaching this task. In this work, predicting a set of future paths with associated uncertainty was archived by combining LSTMs and MDNs. The evaluation was made on the KITTI and the CityFlow datasets on three type of objects, four prediction horizons and two different points of view (image coordinates and birds-eye vie

Genetics and Genomics of Golden Eagle Populations with Contrasting Demographic Histories

Most species are constrained by geographic barriers to dispersal and geneflow, and such limitations have demographic and genetic consequences. We tested whether a highly vagile bird of prey, the golden eagle (GOEA; Aquila chrysaetos), exhibits disparate genetic signatures among island (Channel Islands, California, USA), peninsular (Baja California Peninsular region, USA) and mainland (California, USA) regions given the contrasting demography and phylogeography among regions. We utilized a SNP assay to estimate heterozygosity, inbreeding coefficients, and the effective population sizes (Ne) of GOEAs. In addition, we sequenced six GOEA genomes to obtain comprehensive measures of homozygosity (i.e., runs of homozygosity, ROHs) burden as well as estimates of nucleotide diversity. Our samples from the Channel Islands were clearly differentiated from both the peninsular and mainland samples, but there was no genetic differentiation between the peninsular and mainland samples. We found that the island samples exhibited signatures of a founder effect, including lower heterozygosity, reduced Ne, and a higher ROH burden than the mainland or peninsular samples. Overall, the genetic markers and the whole-genome sequence data indicate that the Channel Islands samples are genetically distinct from the mainland and peninsular samples, likely as a result of a relatively recent demographic bottleneck followed by bouts of genetic drift and inbreeding. We also found that, unlike smaller and less mobile vertebrates (e.g., rodents, passerines, and lizards), the GOEA gene pool near Baja California is relatively homogenous across distinct phylogeographic domains separated by the San Andreas fault. The genetic isolation exhibited by the island GOEAs almost certainly results from their recent colonization (due to bald eagle extirpation associated with DDT exposure) and subsequent anthropogenic removal (due to predation on an endangered island fox)

Exploring the Efficacy of Social Media Based HIV Prevention Strategies for Hispanic College Students

Hispanics now constitute the largest ethnic minority group in the U.S. As the country’s fastest growing demographic, social welfare and public health professionals should focus on ameliorating health issues affecting this population. However, Hispanics continue to experience health disparities including high rates of HIV infection. Moreover, South Florida, is home to two counties with the highest per capita incidence of HIV in the U.S. Risks for HIV are heightened in college settings where individuals may have multiple partners and inconsistent condom use. As such, Hispanic college students in a minority serving institution in Miami, FL comprise an ideal group for the implementation of targeted prevention efforts to decrease health disparities related to HIV. This dissertation evaluated the implementation of an HIV prevention effort that utilized social media based technologies to engage Hispanic college students in HIV prevention conversations and services. This dissertation (1) evaluated the effectiveness of exposure to a social media based campaign using an experimental design and (2) provided a systematic review of the campaign’s content and user interactivity. Participants were recruited from students electing to receive free HIV testing on-campus as part of a SAMHSA-funded project. Hispanic young adults (ages 18-24 years) completed baseline and follow-up assessments—reporting demographic and background characteristics as well as perceptions and incorporation of HIV preventive behaviors. Participants were randomized to social media exposure (n=30) or control (n=30) conditions. The exposure condition received three updates per week in the form of social media post updates. Follow-up assessments occurred 4 weeks after HIV testing. Mixed ANOVA and logistic regression analysis were used to examine the impact of exposure over time by comparing mean scores of baseline and follow-up responses between conditions. This dissertation examined the following outcomes: awareness of HIV testing and prevention services, confidence of using condoms, perceived benefits of using condoms, and frequency of reported protected sex acts. While analyses revealed no statistically significant differences between groups, McNemar’s test results indicated a statistically significant increase in awareness of HIV prevention services on the university campus for participants in both study conditions (p\u3c .001). These exploratory results indicate further research is needed to determine the effectiveness of social media based strategies and how such technologies should be harnessed to achieve HIV prevention goals

Dual regimes of ion migration in high repetition rate femtosecond laser inscribed waveguides

Ion migration in high repetition rate femtosecond laser inscribed waveguides is currently being reported in different optical glasses. For the first time we discuss and experimentally demonstrate the presence of two regimes of ion migration found in laser written waveguides. Regime-I, corresponds to the initial waveguide formation mainly via light element migration (in our case atomic weight < 31u), whereas regime-II majorly corresponds to the movement of heavy elements. This behavior brings attention to a problem which has never been analyzed before and that affects laser written active waveguides in which active ions migrate changing their local spectroscopic properties. The migration of active ions may in fact detune the pre-designed optimal values of active photonic devices. This paper experimentally evidences this problem and provides solutions to avert it.Comment: 4 pages, 5 figure