Fysisk aktivitet i kroppsøving : en felteksperimentell studie på videregående elever

Formål: Studiens formål var å undersøke om et utvalg elever i den videregående skole ble stimulert til å være i tilstrekkelig fysisk aktivitet i kroppsøvingstimene, i forhold til helsemyndigheters anbefalinger for kroppsøving. Metode: 62 elever (37 gutter og 25 jenter) var med i undersøkelsen. Utvalget var fra en studiespesialisert klasse og to yrkesfaglige klasser. Datainnsamlingen foregikk på fire kroppsøvingsøkter: Sirkeltrening, turn og frisbee, innebandy og utholdenhetstrening. Aktivitetsnivået målt med akselerometer. Observasjon av timen ble gjennomført for å styrke den økologiske validiteten til studien. Resultat: Elevene i denne studien var i moderat til hard aktivitet 41,5 % av tiden, noe som er under anbefalingene for fysisk aktivitet i kroppsøvingstimer. Turn og frisbee var den eneste aktiviteten som var i moderat til hard aktivitet 50 % av tiden, mens innebandy var aktiviteten med lavest aktivitetsnivå med moderat til hard aktivitet 9,5 % av tiden. Målinger med akselerometer fant ingen signifikante forskjeller mellom studiespesialiserte og yrkesfaglige elever, en fant heller ikke forskjell mellom gutter og jenter. Diskusjon: Min studie viser at elever i den videregående skole ikke blir tilstrekkelig stimulert til fysisk aktivitet i kroppsøvingstimene. Som følge av en lav svarprosent og en ikke-sannsynlighetsutvelgelse av respondenter kan en kun se trender, ikke generalisere resultatene

The effect of estrus synchronization and post-partum interval on fertility in beef cattle

Call number: LD2668 .T4 1978 O36Master of Scienc

Effect of post-partum breeding interval on conception rates in beef cows

We analyzed date on 1536 fall calving Angus cows to determine the effect of post-partum breeding interval on conception rates in beef cows. Normal fertility was observed for cows showing heat 40 or more days post-partum

Cell-Length-Dependent Microtubule Accumulation during Polarization

SummaryBackgroundBreaking cell symmetry, known as polarization, requires dynamic reorganization of microtubules (MTs) and is essential to many cellular processes, including axon formation in neurons. A critical step in polarization is believed to be the “selective stabilization” of MTs, which hypothesizes a spatial and/or temporal shift toward net MT assembly in a preferred direction of growth.ResultsWe now find that a simpler “length-dependent” model, in which MT assembly parameters are spatially and temporally constant, predicts MT accumulation in the direction of growth because of longer mean first passage times in the longer direction. We experimentally tested both models by tracking MT assembly dynamics in polarizing embryonic chick forebrain neurons, and we confirmed that assembly is spatially and temporally constant during axon formation.ConclusionCell polarization occurs most simply through cell-length-dependent accumulation of MTs without MT stabilization or capture. In this way, F-actin-mediated cell shape and size changes can be read out by dynamic MTs undergoing simple dynamic instability to ultimately break cell symmetry

Optical Control of Microtubule Dynamics in Time and Space

Small molecule inhibitors of microtubule dynamics are widely used as cell biology research tools and clinically as cancer chemotherapeutics. By slight modification to the chemical structure of a known microtubule inhibitor, combretastatin A-4, Borowiak et al. develop a photoswitchable derivative that can be turned “on” and “off” with low-intensity light to spatially and temporally control microtubule dynamics

Regulation of the MEX-5 Gradient by a Spatially Segregated Kinase/Phosphatase Cycle

SummaryProtein concentration gradients encode spatial information across cells and tissues and often depend on spatially localized protein synthesis. Here, we report that a different mechanism underlies the MEX-5 gradient. MEX-5 is an RNA-binding protein that becomes distributed in a cytoplasmic gradient along the anterior-to-posterior axis of the one-cell C. elegans embryo. We demonstrate that the MEX-5 gradient is a direct consequence of an underlying gradient in MEX-5 diffusivity. The MEX-5 diffusion gradient arises when the PAR-1 kinase stimulates the release of MEX-5 from slow-diffusive, RNA-containing complexes in the posterior cytoplasm. PAR-1 directly phosphorylates MEX-5 and is antagonized by the spatially uniform phosphatase PP2A. Mathematical modeling and in vivo observations demonstrate that spatially segregated phosphorylation and dephosphorylation reactions are sufficient to generate stable protein concentration gradients in the cytoplasm. The principles demonstrated here apply to any spatially segregated modification cycle that affects protein diffusion and do not require protein synthesis or degradation

The Reluctance of Cattle to Change a Learned Choice May Confound Preference Tests

The conclusion of the article states "it appears that previously learned choices may affect future choices in Y-mazes for cattle. Another area that needs to be researched is the effects of a mildly aversive treatment versus a severely aversive treatment on the tendency of a bovine to resist changing a learned choice"

Raltegravir, elvitegravir, and metoogravir: the birth of "me-too" HIV-1 integrase inhibitors

Merck's MK-0518, known as raltegravir, has recently become the first FDA-approved HIV-1 integrase (IN) inhibitor and has since risen to blockbuster drug status. Much research has in turn been conducted over the last few years aimed at recreating but optimizing the compound's interactions with the protein. Resulting me-too drugs have shown favorable pharmacokinetic properties and appear drug-like but, as expected, most have a highly similar interaction with IN to that of raltegravir. We propose that, based upon conclusions drawn from our docking studies illustrated herein, most of these me-too MK-0518 analogues may experience a low success rate against raltegravir-resistant HIV strains. As HIV has a very high mutational competence, the development of drugs with new mechanisms of inhibitory action and/or new active substituents may be a more successful route to take in the development of second- and third-generation IN inhibitors