5,246 research outputs found

    A GUIDE TO SWINE MARKETING CONTRACTS

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    Livestock Production/Industries, Marketing,

    The slipper lobster, Scyllarides latus, uses apatite and fluorapatite to protect its sensory organules

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    The cuticle of arthropods has been intensely studied not only to better understand the properties of a natural composite material, but also to understand how structural properties and mineral contributions to this composite offer a durable protective covering from predator and microbial attack. Thus far, most marine cuticular studies have focused on the American lobster, Homarus americanus, or several crab species, but have largely ignored other types of lobsters, such as spiny or slipper lobsters that have exoskeletons differing in both structural properties (i.e., amount of trabeculae present in pits and spines) and resistance to structural failure. Using an electron microprobe, we analyzed various segments of the exoskeleton of the Mediterranean slipper lobster, Scyllarides latus, to determine the mineral content in discrete domains of cuticle. EMP analysis determined that the cuticle of S. latus is similar to that of H. americanus in that it contains carbonate apatite in canal linings and in the areas surrounding sensory organules (setae). The slipper lobster also uses a fluorapatite mineral that further adds strength to the shell. Results will be discussed in the context of what this means for defense against attack and differences in environmental water chemistry and resilience to climate change

    Failure of Opioids to Modify Noradrenergic Neuronal Recovery From a Dorsal Bundle Lesion in Neonatal Rats

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    Morphine and exogenous opioid peptides alter the development of central noradrenergic neurons damaged by neonatal treatment with the neurotoxin 6-hydroxydopa. Transection of the dorsal noradrenergic bundle (DNB) in neonatal rats produces nearly the same alteration in the developmental pattern. It was of interest to determine whether morphine or an exogenous opioid peptide (metenkephalin) was able to modify the recovery of noradrenergic neurons after neonatal surgical transection of the DNB. Neonatal rats were divided into two groups. Both groups received saline (0.85%) or naloxone (2.0 mg/kg) by the intraperitoneal (i.p.) route. In the first group the animals received an additional i.p. injection of either saline or morphine sulfate (3.33 mg/kg). The second group received an intraventricular injection of either saline, morphine (10 (mu)g/5 (mu)l), or methionine-enkephalin (25 (mu)g/5 (mu)l) ten minutes after the i.p. injection. Half the animals in these groups then received a DNB lesion, made with a blade 3mm (depth) by 5mm (width) at the level of the colliculi. At 6 weeks brains were removed for assay of norepinephrine (NE) content by a fluorometric method, and for determination of the rate of (\u273)H-NE uptake, in order to assess noradrenergic fiber number. It was found that in the cerebellum both the (\u273)H-NE uptake rate and NE content were significantly elevated by approximately 75% in the animals that received the lesion. The recovery in the anterior cortex (39%) was significantly greater than in the posterior cortex (27%), while recovery in the hippocampus (21%) was the least. This indicates a regional difference in recovery in the more distal projections of the DNB. Within the lesion group, however, there was no alteration in (\u273)H-NE uptake rate nor NE content in any of the above regions with any of the drug treatments. Therefore, none of the drug treatments effectively altered the recovery from surgical transection of the DNB. It is suggested that opioids are capable of modifying neurotoxin damage per se, but not capable of modifying regeneration of noradrenergic neurons

    The Role of Arachidonic Acid Metabolites in Mononuclear Phagocytic Cell Interactions

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65162/1/j.1365-4362.1986.tb04543.x.pd

    Completions of implicitly defined linear time varying vector fields

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    AbstractThe stabilization of constraints through such techniques as Baumgarte stabilization has been used in the simulation community for some time. This and a number of control problems can be viewed as either extending, or modifying, a vector field off of some manifold. Generally these approaches required the equations to have a special structure. Motivated by numerical simulation there has recently been new progress on doing this stabilization in numerically robust ways for larger classes of systems. In this paper we point out how earlier linear time invariant results do not immediately apply to the linear time varying case and then analyze the linear time varying case

    Artifact Rejection Methodology Enables Continuous, Noninvasive Measurement of Gastric Myoelectric Activity in Ambulatory Subjects.

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    The increasing prevalence of functional and motility gastrointestinal (GI) disorders is at odds with bottlenecks in their diagnosis, treatment, and follow-up. Lack of noninvasive approaches means that only specialized centers can perform objective assessment procedures. Abnormal GI muscular activity, which is coordinated by electrical slow-waves, may play a key role in symptoms. As such, the electrogastrogram (EGG), a noninvasive means to continuously monitor gastric electrical activity, can be used to inform diagnoses over broader populations. However, it is seldom used due to technical issues: inconsistent results from single-channel measurements and signal artifacts that make interpretation difficult and limit prolonged monitoring. Here, we overcome these limitations with a wearable multi-channel system and artifact removal signal processing methods. Our approach yields an increase of 0.56 in the mean correlation coefficient between EGG and the clinical "gold standard", gastric manometry, across 11 subjects (p < 0.001). We also demonstrate this system's usage for ambulatory monitoring, which reveals myoelectric dynamics in response to meals akin to gastric emptying patterns and circadian-related oscillations. Our approach is noninvasive, easy to administer, and has promise to widen the scope of populations with GI disorders for which clinicians can screen patients, diagnose disorders, and refine treatments objectively
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