1,463 research outputs found
Glucosamine supplementation during late gestation alters placental development and increases litter size
Background:
During late gestation the placental epithelial interface becomes highly folded, which involves changes in stromal hyaluronan. Hyaluronan is composed of glucoronate and N-acetyl-glucosamine. We hypothesized that supplementing gestating dams with glucosamine during this time would support placental folded-epithelial-bilayer development and increase litter size. In Exp. 1, gilts were unilaterally hysterectomizedovariectomized (UHO). UHO gilts were mated and then supplemented daily with 10 g glucosamine (n = 16) or glucose (control, n = 17) from d 85 of gestation until slaughter (d 105). At slaughter, the number of live fetuses was recorded and each live fetus and its placenta was weighed. Uterine wall samples adjacent to the largest and smallest fetuses within each litter were processed for histology. In Exp. 2, pregnant sows in a commercial sow farm were supplemented with either 10 g glucosamine or glucose daily from d 85 of gestation to farrowing. Total piglets born and born alive were recorded for each litter. In Exp. 3, the same commercial farm and same protocol were used except that the dose of glucosamine and glucose was doubled to 20 g/d.
Results:
In Exp. 1, the number of live fetuses tended to be greater in glucosamine-treated UHO gilts (P = 0.098). Placental morphometry indicated that the width of the folded bilayer was greater (P = 0.05) in glucosamine-treated gilts. In Exp. 2, litter size did not differ between glucosamine- and glucose-treated sows. However in Exp. 3, the increased dose of glucosamine resulted in a significant treatment by parity interaction (P ≤ 0.01), in which total piglets born and born alive were greater in glucosamine treated sows of later parity (5 and 6).
Conclusions:
These results indicated that glucosamine supplementation increased the width of the folds of the placental bilayer and increased litter size in later parity, intact pregnant commercial sows
Identification to species level of live single microalgal cells from plankton samples with matrix-free laser/desorption ionization mass spectrometry
Beams in the CERN PS complex after the RF upgrades for LHC
In preparation for the Large Hadron Collider (LHC), extensive modifications have been made to the RF equipment of the PS Booster (PSB) and of the PS during the winter shut down 97-98. Low-frequency RF systems (0.6 - 1.8 MHz and 1.2 - 3.9 MHz) have been installed in the PSB and fixed frequency (40 and 80 MHz) systems in the PS. The longitudinal characteristics of all beams are changed to make the best use of the new capabilities. This paper summarises the characteristics of the new equipment and describes the RF gymnastics used to generate the various beams. The performances achieved so far ar e reported and compared to former results. Future plans are sketched
High-resolution data reveal a surge of biomass loss from temperate and Atlantic pine forests, contextualizing the 2022 fire season distinctiveness in France
The frequency and intensity of summer droughts and heat
waves in Western Europe have been increasing, raising concerns about the
emergence of fire hazard in less fire-prone areas. This exposure of
old-growth forests hosting unadapted tree species may cause
disproportionately large biomass losses compared to those observed in
frequently burned Mediterranean ecosystems. Therefore, analyzing fire
seasons from the perspective of exposed burned areas alone is insufficient;
we must also consider impacts on biomass loss. In this study, we focus on
the exceptional 2022 summer fire season in France and use very
high-resolution (10 m) satellite data to calculate the burned area, tree
height at the national level, and subsequent ecological impact based on
biomass loss during fires. Our high-resolution semi-automated detection
estimated 42 520 ha of burned area, compared to the 66 393 ha estimated by
the European automated remote sensing detection system (EFFIS), including
48 330 ha actually occurring in forests. We show that Mediterranean forests
had a lower biomass loss than in previous years, whereas there was a drastic
increase in burned area and biomass loss over the Atlantic pine forests and
temperate forests. High biomass losses in the Atlantic pine forests were
driven by the large burned area (28 600 ha in 2022
vs. 494 ha yr−1 in
2006–2021 period) but mitigated by a low exposed tree biomass mostly located
on intensive management areas. Conversely, biomass loss in temperate forests
was abnormally high due to both a 15-fold increase in burned area compared
to previous years (3300 ha in 2022 vs. 216 ha in the 2006–2021 period) and
a high tree biomass of the forests which burned. Overall, the biomass loss
(i.e., wood biomass dry weight) was 0.25 Mt in Mediterranean forests and
shrublands, 1.74 Mt in the Atlantic pine forest, and 0.57 Mt in temperate
forests, amounting to a total loss of 2.553 Mt, equivalent to a 17 %
increase of the average natural mortality of all French forests, as reported
by the national inventory. A comparison of biomass loss between our
estimates and global biomass/burned areas data indicates that higher
resolution improves the identification of small fire patches, reduces the
commission errors with a more accurate delineation of the perimeter of each
fire, and increases the biomass affected. This study paves the way for the
development of low-latency, high-accuracy assessment of biomass losses and
fire patch contours to deliver a more informative impact-based
characterization of each fire year.</p
Identification of Quantitative Trait Loci Affecting Female Reproductive Traits in a Multigeneration Meishan-White Composite Swine Population
A multigeneration crossbred Meishan- White composite resource population was used to identify quantitative trait loci (QTL) for age at first estrus (AP) and the components of litter size: ovulation rate (OR; number of ova released in an estrous period) and uterine capacity (UC). The population was established by reciprocally mating Meishan (ME) and White composite (WC) pigs. Resultant F1 females were mated to either ME or WC boars to produce backcross progeny (BC) of either ¾ WC ¼ ME or ¼ WC ¾ ME. To produce the next generation (F3) , ¾ WC ¼ ME animals were mated to ¼ WC ¾ ME animals yielding half-blood (½ WC ½ ME) progeny. A final generation (F4) was produced by inter se mating F3 animals. Measurements for AP and OR were recorded on 101 BC, 389 F3, and 110 F4 gilts, and UC data were from 101 BC and 110 F4 first parity litters. A genomic scan was conducted with markers (n = 157) spaced &#;20 cM apart. All parental, F1, BC, and F4 animals but only 84 F3 animals were genotyped and included in this study. The QTL analysis fitted a QTL at 1-cM intervals throughout the genome, and QTL effects were tested using approximate genome-wide significance levels. For OR, a significant (E[false positive] \u3c .05) QTL was detected on chromosome 8, suggestive (E[false positive] \u3c 1.0) QTL were detected on chromosomes 3 and 10, and two additional regions were detected that may possess a QTL (E[false positive] \u3c 2.0) on chromosomes 9 and 15. Two regions possessed suggestive evidence for QTL affecting AP on chromosomes 1 and 10, and one suggestive region on chromosome 8 was identified for UC. Further analyses of other populations of swine are necessary to determine the extent of allelic variation at the identified QTL
External and internal noise surveys of London primary schools
Internal and external noise surveys have been carried out around schools in London, UK, to provide information on typical levels and sources to which children are exposed while at school. Noise levels were measured outside 142 schools, in areas away from flightpaths into major airports. 86% of the schools surveyed were exposed to noise from road traffic, the average external noise level outside a school being 57 dB LAeq. Detailed internal noise surveys have been carried out in 140 classrooms in 16 schools, together with classroom observations. It was found that noise levels inside classrooms depend upon the activities in which the children are engaged, with a difference of 20 dB LAeq between the 'quietest' and 'noisiest' activities. The average background noise level in classrooms exceeds the level recommended in current standards. The number of children in the classroom was found to affect noise levels. External noise influenced internal noise levels only when children were engaged in the quietest classroom activities. The effects of the age of the school buildings and types of window upon internal noise were examined but results were inconclusive
A two step algorithm for learning from unspecific reinforcement
We study a simple learning model based on the Hebb rule to cope with
"delayed", unspecific reinforcement. In spite of the unspecific nature of the
information-feedback, convergence to asymptotically perfect generalization is
observed, with a rate depending, however, in a non- universal way on learning
parameters. Asymptotic convergence can be as fast as that of Hebbian learning,
but may be slower. Moreover, for a certain range of parameter settings, it
depends on initial conditions whether the system can reach the regime of
asymptotically perfect generalization, or rather approaches a stationary state
of poor generalization.Comment: 13 pages LaTeX, 4 figures, note on biologically motivated stochastic
variant of the algorithm adde
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