440 research outputs found
Water Intake in Growing Beef Cattle
Water is an essential part of livestock and human diets and is often thought of as an inexpensive, readily available renewable natural resource. However, the amount of competition between humans, wildlife, feed production, and livestock for high-quality water is increasing, not only from the effects of drought but from the pressure of a growing global population (Nardone et al., 2010). With limited resources available for production agriculture, there is a need to identify and select for efficient animals that can produce more product with fewer inputs. Although some work has been done in dairy cattle, very little data is available on individual animal water intake in modern beef cattle (Brew et al., 2011). The majority of the water intake data available in growing beef cattle is derived from dividing the total amount of water drunk in a pen divided by the number of animals in that pen (Sexson et al., 2010; Mader and Davis, 2004). Data derived from groups are not generally useful for the purposes of genetic evaluation, which aims to quantify individual animal variation in a trait for selection. However, in order to practice selection on a large scale, parameters for collecting phenotypic data must be established. The objectives of this study were to measure daily water intake on a large number of beef steers and to estimate the number of test days necessary to collect accurate water intake phenotypes
Polishing material removal correlation on PMMA – FEM simulation
The complexity of polishing is very high and experience in this field is required to achieve reproducible deterministic results concerning shape accuracy. The goal of this work is to predict the material removal of the polishing process on PMMA (Polymethylmethacrylate) using an industrial robot polisher. In order to predict the material removal, a FEM Model was created representing the polishing process. This model will help to predict the material removal when polishing parameters are changed. Experiments were carried out and compared to the results obtained from the different parameters tested in the simulation
The Foot of Homo Naledi
Modern humans are characterized by a highly specialized foot that reflects our obligate bipedalism. Our understanding of hominin foot evolution is, although, hindered by a paucity of well-associated remains. Here we describe the foot of Homo naledi from Dinaledi Chamber, South Africa, using 107 pedal elements, including one nearly-complete adult foot. The H. naledi foot is predominantly modern human-like in morphology and inferred function, with an adducted hallux, an elongated tarsus, and derived ankle and calcaneocuboid joints. In combination, these features indicate a foot well adapted for striding bipedalism. However, the H. naledi foot differs from modern humans in having more curved proximal pedal phalanges, and features suggestive of a reduced medial longitudinal arch. Within the context of primitive features found elsewhere in the skeleton, these findings suggest a unique locomotor repertoire for H. naledi, thus providing further evidence of locomotor diversity within both the hominin clade and the genus Homo
The foot of Homo naledi
Modern humans are characterized by a highly specialized foot that reflects our obligate bipedalism. Our understanding of hominin foot evolution is, although, hindered by a paucity of well-associated remains. Here we describe the foot of Homo naledi from Dinaledi Chamber, South Africa, using 107 pedal elements, including one nearly-complete adult foot. The H. naledi foot is predominantly modern human-like in morphology and inferred function, with an adducted hallux, an elongated tarsus, and derived ankle and calcaneocuboid joints. In combination, these features indicate a foot well adapted for striding bipedalism. However, the H. naledi foot differs from modern humans in having more curved proximal pedal phalanges, and features suggestive of a reduced medial longitudinal arch. Within the context of primitive features found elsewhere in the skeleton, these findings suggest a unique locomotor repertoire for H. naledi, thus providing further evidence of locomotor diversity within both the hominin clade and the genus Homo
The Foot of \u3cem\u3eHomo naledi\u3c/em\u3e
Modern humans are characterized by a highly specialized foot that reflects our obligate bipedalism. Our understanding of hominin foot evolution is, although, hindered by a paucity of well-associated remains. Here we describe the foot of Homo naledi from Dinaledi Chamber, South Africa, using 107 pedal elements, including one nearly-complete adult foot. The H. naledi foot is predominantly modern human-like in morphology and inferred function, with an adducted hallux, an elongated tarsus, and derived ankle and calcaneocuboid joints. In combination, these features indicate a foot well adapted for striding bipedalism. However, the H. naledi foot differs from modern humans in having more curved proximal pedal phalanges, and features suggestive of a reduced medial longitudinal arch. Within the context of primitive features found elsewhere in the skeleton, these findings suggest a unique locomotor repertoire for H. naledi, thus providing further evidence of locomotor diversity within both the hominin clade and the genus Homo
The Glial Regenerative Response to Central Nervous System Injury Is Enabled by Pros-Notch and Pros-NFκB Feedback
Organisms are structurally robust, as cells accommodate changes preserving structural integrity and function. The molecular mechanisms underlying structural robustness and plasticity are poorly understood, but can be investigated by probing how cells respond to injury. Injury to the CNS induces proliferation of enwrapping glia, leading to axonal re-enwrapment and partial functional recovery. This glial regenerative response is found across species, and may reflect a common underlying genetic mechanism. Here, we show that injury to the Drosophila larval CNS induces glial proliferation, and we uncover a gene network controlling this response. It consists of the mutual maintenance between the cell cycle inhibitor Prospero (Pros) and the cell cycle activators Notch and NFκB. Together they maintain glia in the brink of dividing, they enable glial proliferation following injury, and subsequently they exert negative feedback on cell division restoring cell cycle arrest. Pros also promotes glial differentiation, resolving vacuolization, enabling debris clearance and axonal enwrapment. Disruption of this gene network prevents repair and induces tumourigenesis. Using wound area measurements across genotypes and time-lapse recordings we show that when glial proliferation and glial differentiation are abolished, both the size of the glial wound and neuropile vacuolization increase. When glial proliferation and differentiation are enabled, glial wound size decreases and injury-induced apoptosis and vacuolization are prevented. The uncovered gene network promotes regeneration of the glial lesion and neuropile repair. In the unharmed animal, it is most likely a homeostatic mechanism for structural robustness. This gene network may be of relevance to mammalian glia to promote repair upon CNS injury or disease
Stark Broadening of the B III 2s-2p Lines
We present a quantum-mechanical calculation of Stark line widths from
electron-ion collisions for the , lambda = 2066 and 2067
A, resonance transitions in B III. The results confirm the previous
quantum-mechanical R-matrix calculations but contradict recent measurements and
semi-classical and some semi-empirical calculations. The differences between
the calculations can be attributed to the dominance of small L partial waves in
the electron-atom scattering, while the large Stark widths inferred from the
measurements would be substantially reduced if allowance is made for
hydrodynamic turbulence from high Reynolds number flows and the associated
Doppler broadening.Comment: 21 pages, 4 figures; to be published in Phys. Rev.
4-Aminopyridine-induced epileptogenesis depends on activation of mitogen-activated protein kinase ERK
Extracellular signal-regulated kinases such as ERK1 [p44
mitogen-activated protein kinase (MAPK)] and ERK2 (p42
MAPK) are activated in the CNS under physiological and
pathological conditions such as ischemia and epilepsy. Here,
we studied the activation state of ERK1/2 in rat hippocampal
slices during application of the K+ channel blocker 4-aminopyridine
(4AP, 50 lM), a procedure that enhances synaptic
transmission and leads to the appearance of epileptiform
activity. Hippocampal slices superfused with 4AP-containing
medium exhibited a marked activation of ERK1/2 phosphorylation
that peaked within about 20 min. These effects
were not accompanied by changes in the activation state of
c-Jun N-terminal kinase (JNK), another member of the MAP
kinase superfamily. 4AP-induced ERK1/2 activation
was inhibited by the voltage-gated Na+ channel blocker
tetrodotoxin (1 lM). We also found that application of the ERK
pathway inhibitors U0126 (50 lM) or PD98059 (100 lM)
markedly reduced 4AP-induced epileptiform synchronization,
thus abolishing ictal discharges in the CA3 area. The effects
induced by U0126 or PD98059 were not associated with
changes in the amplitude and latency of the field potentials
recorded in the CA3 area following electrical stimuli delivered
in the dentate hylus. These data demonstrate that activation of
ERK1/2 accompanies the appearance of epileptiform activity
induced by 4AP and suggest a cause-effect relationship
between the ERK pathway and epileptiform synchronization
When is a GIST not a GIST? A case report of synchronous metastatic gastrointestinal stromal tumor and fibromatosis
<p>Abstract</p> <p>Background</p> <p>A number of non-malignant diseases that share similar morphological features as gastrointestinal stromal tumor (GIST) have been reported. Co-existence of GIST with these other diseases is rarely recognized or reported.</p> <p>Case presentation</p> <p>We report a case of a 62 year-old man with long-term stable control of metastatic GIST with systemic therapy, presented with an apparent intra-abdominal progression but not supported by imaging with positron emission tomography. Subsequent resection of the intra-abdominal tumor identified a non-malignant fibroid.</p> <p>Conclusion</p> <p>Differentiating localized progression of GIST from other diseases has important prognostic and therapeutic implications. The potential for co-existence of non-malignant soft tissue neoplasm should always be considered.</p
An Experimental Exploration of the QCD Phase Diagram: The Search for the Critical Point and the Onset of De-confinement
The QCD phase diagram lies at the heart of what the RHIC Physics Program is
all about. While RHIC has been operating very successfully at or close to its
maximum energy for almost a decade, it has become clear that this collider can
also be operated at lower energies down to 5 GeV without extensive upgrades. An
exploration of the full region of beam energies available at the RHIC facility
is imperative. The STAR detector, due to its large uniform acceptance and
excellent particle identification capabilities, is uniquely positioned to carry
out this program in depth and detail. The first exploratory beam energy scan
(BES) run at RHIC took place in 2010 (Run 10), since several STAR upgrades,
most importantly a full barrel Time of Flight detector, are now completed which
add new capabilities important for the interesting physics at BES energies. In
this document we discuss current proposed measurements, with estimations of the
accuracy of the measurements given an assumed event count at each beam energy.Comment: 59 pages, 78 figure
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