1,734 research outputs found

    An alternative singularity-free cosmological scenario from cusp geometries

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    We study an alternative geometrical approach on the problem of classical cosmological singularity. It is based on a generalized function f(x,y)=x2+y2=(1−z)znf (x, y) = x^{2} + y^{2} = (1 - z)z^{n} which consists of a cusped coupled isosurface. Such a geometry is computed and discussed into the context of Friedmann singularity-free cosmology where a pre-big bang scenario is considered. Assuming that the mechanism of cusp formation is described by non-linear oscillations of a pre-big bang extended very high energy density field (>3×1094kg/m3> 3 \times 10^{94} kg/m^{3} ), we show that the action under the gravitational field follows a tautochrone of revolution, understood here as the primary projected geometry that alternatively replaces the Friedmann singularity in the standard big bang theory. As shown here this new approach allows us to interpret the nature of both matter and dark energy from first geometric principles.Comment: Proceedings of Sixth International School on Field Theory and Gravitation-2012 - by American Institute of Physic

    Capturing genetic gains in productivity with heterosis

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    The National Swine Registry (NSR) has two long term goals: 1) to register purebred pigs and thus assure breed purity and 2) encourage genetic progress through performance testing - genetic selection programs. The continued production of purebred lines assures that a number of breeds are available to produce females and terminal cross pigs with high levels of heterosis. Purebred breeders, whose customers are commercial swine producers, have produced substantial rates of genetic progress by use of the STAGES program

    The Effects of Long Term Selection for Reduced Backfat and Increased Loin Muscle Area on Meat and Eating Quality Traits in Duroc Swine

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    A study was conducted to evaluate differences in performance, carcass composition, and eating quality characteristics of pigs sired by purebred Duroc boars currently available and pigs sired by purebred Duroc boars from the mid 1980’s. Two lines were developed by splitting and randomly allocating littermate and ½ sib pairs of females to matings by current (CTP) or old (OTP) time period boars. Subsequent boar, barrow, and gilt progeny from two replications were weighed on test at a group mean live weight of 140 lbs. Off-test ultrasonic LMA, BF10, and IMF measurements were collected on 789 pigs at a mean live weight of 240 lb. Records on pigs sired by CTP boars, from both replications (n=556), represented 23 sires while pigs sired by OTP boars (n=231) consisted of 15 sire groups. All available barrows and randomly selected gilts (n=277) were sent to a commercial abattoir and measurements of tenth-rib backfat (CBF10), last rib backfat (CLRBF), last lumbar backfat (CLLBF), and loin muscle area (CLMA) were collected. Chemical intramuscular fat percentage was determined by lab analysis of a loin sample from the 10th rib face of the longissimus muscle. Additional meat and eating quality traits measured were: Minolta reflectance and Hunter L (24 and 48 h); pH (24 h and 7 d); water holding capacity; subjective visual scores for color, marbling, and firmness (48 h); Instron tenderness, cooking loss, and trained sensory panel evaluations (7 d). Six serial ultrasonic measurements of 10th rib loin muscle area (LMA), off-midline backfat (BF10), and intramuscular fat percentage (IMF) from the first replication were collected every two weeks and used to assess deposition rate and growth pattern differences. There was no significant difference in average daily gain of pigs sired by boars from the two time periods. Pigs sired by CTP boars had larger (P \u3c 0.05) LMA measurements and less BF10, while pigs sired by OTP had significantly more IMF. Carcass evaluation revealed larger CLMA measurements, and significantly less CBF10, CLRBF, and CLLBF measurements for pigs sired by CTP boars. Pigs sired by OTP boars had a higher intramuscular fat percentage, lower Instron tenderness values, and higher subjective marbling and color scores than pigs sired by CTP boars (P \u3c 0.05). There were no significant differences between time periods for Minolta reflectance, Hunter L (24 and 48 h), water holding capacity, pH (24 h and 7 d), and subjective firmness scores. Trained sensory evaluations revealed higher (P \u3c 0.05) flavor scores and lower off-flavor scores for OTP sired pigs; however, no significant differences in tenderness score, juiciness score, chewiness score, and cooking loss were found between lines. Progeny of OTP boars began the test period at heavier weights and begin to decrease in daily body weight gain toward the conclusion of the test period, finishing with no advantage in body weight when compared to progeny of CTP boars. The analysis of serial backfat measurements revealed a linear pattern of backfat deposition between 150 and 270 lbs. Pigs sired by OTP boars deposited more backfat (

    Early appearance of 2, 3-butanediol in acute myocardial infarction. A new marker for ischaemia?

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    In 28 patients with acute myocardial infarction, the release pattern of 2, 3-butanediol (BD), a product of intermediary metabolism, and creatine kinase activity (CK) in blood were compared. Whereas CKat entry was low in all patients, the BD level was elevated in 18 (64%). However, BD returned to normal levels during the next 24 h whereas CK increased. The BD level at entry did not allow differentiation between patients with transmural or non-transmural infarction; it was independent of clinical findings and biochemical parameters. We suggest that, in patients with acute myocardial infarction, elevated levels of BD originates from myo-cardial metabolism. Whether it reflects ongoing ischaemia or reperfusion of the infarcted area remains unresolve

    Heat transfer to bodies traveling at high speed in the upper atmosphere

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    A general method has been developed, using the methods of kinetic theory, whereby the surface temperatures of bodies can be calculated for steady flight at any speed in a rarefied gas. The particular solution was made for a flat plate; however, the calculations can be easily extended to bodies of arbitrary shape
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