155 research outputs found
Evaluation of inertial devices for the control of large, flexible, space-based telerobotic arms
Inertial devices, including sensors and actuators, offer the potential of improving the tracking of telerobotic commands for space-based robots by smoothing payload motions and suppressing vibrations. In this paper, inertial actuators (specifically, torque-wheels and reaction-masses) are studied for that potential application. Batch simulation studies are presented which show that torque-wheels can reduce the overshoot in abrupt stop commands by 82 percent for a two-link arm. For man-in-the-loop evaluation, a real-time simulator has been developed which samples a hand-controller, solves the nonlinear equations of motion, and graphically displays the resulting motion on a computer workstation. Currently, two manipulator models, a two-link, rigid arm and a single-link, flexible arm, have been studied. Results are presented which show that, for a single-link arm, a reaction-mass/torque-wheel combination at the payload end can yield a settling time of 3 s for disturbances in the first flexible mode as opposed to 10 s using only a hub motor. A hardware apparatus, which consists of a single-link, highly flexible arm with a hub motor and a torque-wheel, has been assembled to evaluate the concept and is described herein
Using a mixture of cottonseed hulls and cottonseed meal to replace alfalfa hay in diets for stressed feeder calves
One 28-day receiving experiment was
conducted using 625 exotic Ă British cross
heifers to evaluate growth performance and
morbidity on receiving diets that contained
either alfalfa hay or a pellet composed of
65% cottonseed hulls and 35% cottonseed
meal as the roughage source. Heifers fed the
cotton byproduct pellet consumed more feed
(P<0.01) but tended to be less efficient than
those fed alfalfa hay. Daily gain was comparable
between diets (P>0.05), and the percentages
of heifers diagnosed, treated, or
retreated for respiratory disease were similar
Night feeding to reduce bird predation in feedlots
During times of heavy infestations by birds, feedlots can have 25 to 30% increases in feed usage, thereby resulting in large economic losses. Because starlings, blackbirds, grackles, and other avian pests normally feed during daylight hours, we hypothesized that feeding cattle at night would minimize feed contamination and feed loss due to bird infestation. Crossbred beef heifers (n=96; 770 lb) were used to evaluate the effects of feeding at night on performance and carcass characteristics.
Heifers were fed for 107 days during the
months of November to March, when large
bird populations were observed. Feed was delivered once daily at approximately 10:00 a.m. for heifers with continuous access to feed and 30 minutes before dusk for heifers that had access to feed only at night. Feed calls for heifers fed at night were managed so that no feed remained in the bunk at dawn, whereas the control heifers were allowed ad libitum access to feed. Daily feed deliveries per animal (21.51 vs. 18.15 lb for heifers fed continuously or only at night, respectively) were decreased by 16% (P<0.01) when cattle were provided access to feed only at night, but daily gain was not different. Feed efficiency was improved by 14% (P=0.05) with night time feeding, but carcass weights and dressing percentage
remained similar. Overall, feeding cattle only during hours of darkness yielded similar growth performance compared to cattle
fed continuously. However, feed efficiency
was improved substantially, which we attribute to reduced theft by birds
Effects of milk, pasteurized milk, and milk replacer on health and productivity of dairy calves
Dairy Research, 2014 is known as Dairy Day, 2014Our objectives were to determine the health and blood parameters before, during, and
after weaning of 114 Holstein heifers fed either accelerated milk replacer (MR; 28%
CP, 18% fat) or non-saleable milk (3.59 ± 0.28% true protein; 4.12 ± 0.37% fat) that
was either pasteurized (PM) or raw (RM; refrigerated and fed <24 h after collection).
Calves were randomly assigned to feeding treatments at birth. Colostrum (1 L) was fed
less than 14 hours after birth (MR and PM = pasteurized colostrum; RM = raw colostrum).
All calves were bottle-fed 1.8 ± 0.20 L, 3 times daily; all calves were provided
fresh water and grain ad libitum throughout the experiment. Calves began step-down
weaning at age 5 weeks and completed weaning at age 6 weeks. Blood samples were collected
at ages 3, 5, and 7 weeks and were analyzed for complete blood counts (CBC) using
a Procyte Idexx Analyzer (IDEXX Laboratories, Inc., Westbrook, ME). Fecal scores
were observed twice daily, on a 1 to 3 scale (FS1 = normal, FS2 = loose, FS3 = scours).
Results showed that MR-fed calves had more (P < 0.01) observations (%obs) with
FS > 2 than the PM- and RM-fed calves (2.3 vs. 1.6 and 1.7 ± 0.2 %obs, respectively).
In addition, there were no differences in body weight or shoulder or hip height between
treatments, but a treatment Ă week interaction (P = 0.05) occurred for grain consumed,
with a noticeably higher increase between 6 and 7 weeks of age for MR calves.
When CBC was considered, there were no differences in blood cell types, but MR-fed
calves had greater mean corpuscular volume (MCV) than the other calves (P < 0.01),
leading to higher resistance for iron deficiency anemia. In conclusion, these findings
suggest that calf performance and feed intake are not affected by the administration of
raw milk, pasteurized milk, or milk replacer. Moreover, CBC health parameters showed
no significant changes due to administration of the different types of milk sources
Dakota GoldÂź-brand dried distillerâs grains with solubles: effects on finishing performance and carcass characteristics
A 153-day trial was conducted using
345 heifers to determine optimal level of
Dakota Gold dried distillerâs grains with
solubles (DDGS) in finishing diets based
on steam-flaked corn. Diets contained six
levels of DDGS: 0%, 15%, 30%, 45%,
60%, and 75%. DDGS affected average
daily gain, final weight and hot carcass
weight, all of which increased with 15%
DDGS and then decreased as additional
DDGS was added. Growth performance of
heifers fed 30% DDGS was similar to those
fed no DDGS. In general, heifers were
overfinished, with 61% being Yield Grade
3 or greater and 83% grading Choice or
Prime. Backfat tended to decrease with
addition of DDGS, and kidney, pelvic, and
heart fat and marbling scores tended to be
greatest for intermediate levels of DDGS.
Percentage of carcasses grading Choice or
Prime tended to be lower for heifers fed 60
or 75% DDGS
Evaluation of RalgroÂź on pasture and subsequent feedlot performance and carcass merit of mexican crossbred steers
A pasture/feedlot field study was conducted
to evaluate the effects of a single
RalgroÂź implant during the stocker phase on
steer grazing performance and subsequent
feedlot performance and carcass merit. A
total of 2,764 steers of Mexican origin averaging
449 lb were assembled in Texas and
shipped to Kansas, where they grazed on
three intensively-early-stocked Flint Hills
pastures. At initial processing, the steers
were individually weighed and randomly
assigned to either a non-implanted control
group or a Ralgro implant group. Ralgro
steers gained more (23 lb; P<0.01) than
controls during the 82- to 93-day grazing
phase. Following the grazing phase, all steers
were shipped to a commercial feedlot in
southwestern Kansas where steers from each
pasture were individually weighed and given
a single Component E-SÂź implant. Immediately
after processing, steers from each
pasture were sorted into either a light- or
heavy-weight pen, regardless of pasture
implant treatment, resulting in six feedlot
pens. Days on feed ranged from 127 to 197.
Control steers gained faster (P<0.01) during
the feedlot phase; however, Ralgro steers had
higher cumulative weight gains across the
combined pasture and feedlot phases
(P<0.01) and averaged three fewer days on
feed (P<0.05). There were no significant
differences for marbling, fat thickness, ribeye
area, KPH fat, or yield grade. Ralgro
steers had lower (P<0.05) quality grades
because of a higher incidence (P<0.001) of
steers with B and C carcass maturities
Effects of Dietary Energy Concentration and Feed Intake on Growth Performance of Newly Received Growing Cattle Fed Diets Based on Corn and Corn Co-Products
Objective:This studyâs focus was to evaluate if feeding equal amounts of energy from a high-energy limit-fed diet has an effect on growth performance of growing beef cattle when compared to traditional high-roughagead libitumdiets.
Study Description:A total of 392 crossbred heifers were fed one of four experimental diets for a 70-day receiving period. Treatments included a high-roughage diet formulated to provide 45 Mcal of net energy for gain (NEg) per 100 lb of dry matter (DM) and fed forad libitumintake (AL) or a high-energy diet formulated to provide 60 Mcal of NEgper 100 lb of DM and fed at 75% (LIM-75), 80% (LIM-80), or 85% (LIM-85) ofad libitumintake. Treatments were designed to equalize for energy intake between calves assigned to AL and LIM-75.
The Bottom Line:Restricting feed intake while maintaining energy intake does not negatively influence growth performance of newly received growing beef cattle. In times of high forage cost or shortened growing periods producers could program gains based on their own financial and personal needs
Fine-mapping of the HNF1B multicancer locus identifies candidate variants that mediate endometrial cancer risk.
Common variants in the hepatocyte nuclear factor 1 homeobox B (HNF1B) gene are associated with the risk of Type II diabetes and multiple cancers. Evidence to date indicates that cancer risk may be mediated via genetic or epigenetic effects on HNF1B gene expression. We previously found single-nucleotide polymorphisms (SNPs) at the HNF1B locus to be associated with endometrial cancer, and now report extensive fine-mapping and in silico and laboratory analyses of this locus. Analysis of 1184 genotyped and imputed SNPs in 6608 Caucasian cases and 37 925 controls, and 895 Asian cases and 1968 controls, revealed the best signal of association for SNP rs11263763 (P = 8.4 Ă 10(-14), odds ratio = 0.86, 95% confidence interval = 0.82-0.89), located within HNF1B intron 1. Haplotype analysis and conditional analyses provide no evidence of further independent endometrial cancer risk variants at this locus. SNP rs11263763 genotype was associated with HNF1B mRNA expression but not with HNF1B methylation in endometrial tumor samples from The Cancer Genome Atlas. Genetic analyses prioritized rs11263763 and four other SNPs in high-to-moderate linkage disequilibrium as the most likely causal SNPs. Three of these SNPs map to the extended HNF1B promoter based on chromatin marks extending from the minimal promoter region. Reporter assays demonstrated that this extended region reduces activity in combination with the minimal HNF1B promoter, and that the minor alleles of rs11263763 or rs8064454 are associated with decreased HNF1B promoter activity. Our findings provide evidence for a single signal associated with endometrial cancer risk at the HNF1B locus, and that risk is likely mediated via altered HNF1B gene expression
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(Abridged) We describe here the most ambitious survey currently planned in
the optical, the Large Synoptic Survey Telescope (LSST). A vast array of
science will be enabled by a single wide-deep-fast sky survey, and LSST will
have unique survey capability in the faint time domain. The LSST design is
driven by four main science themes: probing dark energy and dark matter, taking
an inventory of the Solar System, exploring the transient optical sky, and
mapping the Milky Way. LSST will be a wide-field ground-based system sited at
Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m
effective) primary mirror, a 9.6 deg field of view, and a 3.2 Gigapixel
camera. The standard observing sequence will consist of pairs of 15-second
exposures in a given field, with two such visits in each pointing in a given
night. With these repeats, the LSST system is capable of imaging about 10,000
square degrees of sky in a single filter in three nights. The typical 5
point-source depth in a single visit in will be (AB). The
project is in the construction phase and will begin regular survey operations
by 2022. The survey area will be contained within 30,000 deg with
, and will be imaged multiple times in six bands, ,
covering the wavelength range 320--1050 nm. About 90\% of the observing time
will be devoted to a deep-wide-fast survey mode which will uniformly observe a
18,000 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . The
remaining 10\% of the observing time will be allocated to projects such as a
Very Deep and Fast time domain survey. The goal is to make LSST data products,
including a relational database of about 32 trillion observations of 40 billion
objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures
available from https://www.lsst.org/overvie
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