EC67-1421 Nebraska Turkey Production Prospectus

Extension Circular 67-1421 talks about past and predicts future prospects for turkey production in the US

Local bifurcations in differential equations with state-dependent delay

This is the author accepted manuscript. The final version is available from AIP Publishing via the DOI in this record.A common task when analysing dynamical systems is the determination of normal forms near local bifurcations of equilibria. As most of these normal forms have been classified and analysed, finding which particular class of normal form one encounters in a numerical bifurcation study guides follow-up computations. This paper builds on normal form algorithms for equilibria of delay differential equations with constant delay that were developed and implemented in DDE-Biftool recently. We show how one can extend these methods to delay-differential equations with state-dependent delay (sd-DDEs). Since higher degrees of regularity of local center manifolds are still open for sd-DDEs, we give an independent (still only partial) argument which phenomena from the truncated normal must persist in the full sd-DDE. In particular, we show that all invariant manifolds with a sufficient degree of normal hyperbolicity predicted by the normal form exist also in the full sd-DDEJ.S. gratefully acknowledges the financial support of the EPSRC via grants EP/N023544/1 and EP/N014391/1. J.S. has also received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement number 643073

1978 Nebraska Beef Cattle Report

Retail value of wholesale meat cuts is influenced by quality and the proportion of lean, fat and bone. Wholesale cuts vary widely in value; for example, loins and ribs sell for more than rounds, rounds more than chucks, and chucks more than flanks, plates, or briskets. This value difference has prompted many attempts to find breeding and feeding systems that will increase the proportion of high-priced cuts. Results shown here characterize the composition of carcass wholesale cuts from 14 breed combinations that were part of a cattle germ plasm evaluation program at the U.S. Meat Animal Research Center, Clay Center, Neb. The program involved breeding Hereford and Angus cows by artificial insemination to Hereford, Angus, Jersey, South Devon, Limousin, Charolais and Simmental sires to produce three calf crops. Calves averaged 215-daysold at weaning and were fed an average of 243 days before slaughtering

Beurteilung der Lungengesundheit von Schweinen aus verschiedenen ökologischen Haltungssystemen mittels BAL und Lungenhistologie

Im vorliegenden Forschungsvorhaben wurde die Lungengesundheit von Schweinen in Abhängigkeit von verschiedenen Haltungs- und Managementbedingungen beschrieben. Die Untersuchung erfolgte an Mastschweinen verschiedener Herkünfte (konventionell – ökologischer Tiefstreustall – Stall nach EU-Öko-VO – Freilandhaltung) und an Tieren unterschiedlichen Alters. In der konventionellen Schweinemast handelte es sich hierbei um Ferkel, Läufer und Mastschweine derselben Herkunft, in der ökologischen Schweinemast um Läufer, Mastschweine und XXL-Schweine von jeweils zwei Beständen. Letztere Untersuchung diente vor allem der Abbildung möglicher Effekte von Unterschieden im betrieblichen und Hygienemanagement auf die Tiergesundheit in den beiden ökologischen Beständen. Der Gesundheitszustand der Tiere mit Betonung des Lungenbefundes wurde über Schlachtkörperuntersuchungen, bronchoalveoläre Lavage (BAL) und histologische Untersuchung makroskopisch auffälliger Lungenbefunde erfasst. Allgemein wurde festgestellt, dass die Tiere im Zeitverlauf und in Abhängigkeit von den Haltungsbedingungen Zeichen einer zunehmenden entzündlichen Veränderung im Bereich der Atemwege zeigten (BAL: prozentuale Reduktion der Makrophagen bei gleichzeitigem relativen Anstieg der Lymphozyten). Die histologische Untersuchung wies auf ein unterschiedlich ausgeprägtes v.a. viral bedingtes infektiöses Geschehen hin, das möglicherweise durch eine in unterschiedlichem Ausmaß bestehende irritative Schädigung der Atemwege gefördert wurde. Sowohl bei Untersuchung der Mastschweine als auch bei Probenahme bei unterschiedlich alten Tieren wurde deutlich, dass den Managementfaktoren (Entwurmung, Impfstatus, Hygiene) eine bedeutende Rolle im Hinblick auf den Gesundheitszustand zukommt. Im negativen Fall führte dieser Effekt dazu, dass die Anzahl auffälliger Befunde trotz vergleichsweiser guter Stallluftqualität (sehr) hoch war. Neben baulich-technischen Faktoren kommt folglich dem Management eine sehr große Bedeutung zu

Immunotoxicology: challenges in the 21st century and in vitro opportunities

Over the last two decades, little has changed in the practice of immunotoxicity testing for regulatory purposes, especially for immunosuppression, and autoimmunity is still a challenge. Current guidelines still rely on animal tests, which include some immune endpoints in repeated dose tests and trigger dedicated tests only when certain alerts indicate a problem. At the same time, however, a wealth of in vitro approaches has been developed, but few have been adopted for routine testing. The extent to which immunotoxicity of chemicals represents a health problem for the human population at low levels of exposure is unclear: it appears that responses of healthy individuals to immunological challenges differ widely and most immunomodulators have few adverse effects except when they coincide with an infectious or malignant challenge or when early in life exposure is expected, in which cases the odds of progressing into infection, autoimmune diseases, or cancer can be changed. The enormous overcapacity of immune defense, the presence of compensatory mechanisms, and their fast restoration each contribute to limiting health threats for the individual, though on a population base also minor immunomodulation may result in increased morbidity. In vitro alternative approaches may allow screening for problematic substances and prioritize them for in vivo testing. New approaches are emerging from mapping pathways of immunotoxicity. Increasingly, the contribution of inflammatory and infectious components to the adverse outcome pathways of chemicals is recognized for various hazards, urging inclusion of tests for proinflammatory and immunomodulatory properties of chemicals into integrated testing strategies

Hybridization of electron subbands in a double quantum well at quantizing magnetic field

We employ magnetocapacitance and far-infrared spectroscopy techniques to study the spectrum of the double-layer electron system in a parabolic quantum well with a narrow tunnel barrier in the centre. For gate-bias-controlled asymmetric electron density distributions in this soft two-subband system we observe both individual subband gaps and double layer gaps at integer filling factor $\nu$. The bilayer gaps are shown to be either trivial common for two subbands or caused by hybridization of electron subbands in magnetic field. We describe the observed hybrid gaps at $\nu=1$ and $\nu=2$ within a simple model for the modified bilayer spectrum.Comment: REVTeX, 24 pages, 9 figures included. Submitted to Phys. Rev.

Fragen des Arbeits-, Tier- und Umweltschutzes bei der Schweinemast in verschiedenen Systemen unter besonderer Berücksichtigung mikrobieller Belastungen

Vor dem Hintergrund häufiger Atemwegserkrankungen bei Schweinen und landwirtschaftlich Beschäftigten war es das Ziel eines interdisziplinären Verbundprojektes, Belastungen von Mensch, Tier und Umwelt in ökologischen und konventionellen Haltungssystemen für die Schweinemast zu erfassen. Die Untersuchungen wurden in zwei konventionellen (Stall A, B) (BVT-Stall, 50% reduzierter Schlitzanteil, Zwangsbelüftung) und zwei ökologischen Ställen durchgeführt: Stall C (Praxisstall: Tiefstreu, freie Fenster-Lüftung), Stall D (Praxisstall: EU-Öko-VO, Trauf-First-Lüftung). Über 2 Mastperioden (je 3 Messungen; kalte / warme Jahreszeit) wurden die Parameter erfasst: luftgetragene Endotoxine, Schimmelpilze, Bakterien mit Differenzierung, arbeitsmedizinische Staubfraktionen, Materialproben, Staubfraktion PM10, NH3, CO2 und CH4, Lufttemperatur, Luftfeuchte. Die Beschreibung der Tiergesundheit erfolgte über serologische (Mycoplasmen, PRRS-, Influenza-A- und Circo-Virus) und koprologische (Parasitenbefall) Analysen und über Schlachtkörper- und Organbefundungen (Lunge, Pleura, Perikard, Leber). Am Beispiel der Endotoxin-Konzentration wurden die z.T. sehr hohen biologischen Belastungen deutlich: Stall C (Median: 14.495 EU/m3), Stall A/B (5.544 EU/m3), Stall D (2.876 EU/m3). Personengetragene Messungen führten zu deutlich höheren Werten. Die CO2- und NH3-Konzentrationen lagen in allen Ställen im Durchschnitt deutlich unter dem Grenzwert von 3000 ppm bzw. 20 ppm. In Stall C und D war die CH4-Konzentration allerdings höher als in Stall A/B (oberer Bereich der Literaturangaben). Auffällige Lungenbefunde fanden sich bei ca. 45% der untersuchten Schlachttiere, unabhängig vom Haltungssystem; parasitäre Leberveränderungen wurden ausschließlich in den Ställen C und D ermittelt. Die Untersuchungsergebnisse unterstreichen die Bedeutung der Ausführung, Dimensionierung und Regelung des Lüftungssystems sowie die Sauberkeit bzw. Hygiene und insbesondere das Betriebsmanagement im Stall und ihre Schlüsselrolle hinsichtlich der Freisetzungsmengen von Schadstoffen sowie der Tiergesundheit. Demgegenüber kommt der Klassifizierung der Haltungsumwelt durch die Einteilung in Haltungssystemen nur eine geringe Aussagekraft zu

Magnetic-Field-Induced Hybridization of Electron Subbands in a Coupled Double Quantum Well

We employ a magnetocapacitance technique to study the spectrum of the soft two-subband (or double-layer) electron system in a parabolic quantum well with a narrow tunnel barrier in the centre. In this system unbalanced by gate depletion, at temperatures T\agt 30 mK we observe two sets of quantum oscillations: one originates from the upper electron subband in the closer-to-the-gate part of the well and the other indicates the existence of common gaps in the spectrum at integer fillings. For the lowest filling factors $\nu=1$ and $\nu=2$, both the common gap presence down to the point of one- to two-subband transition and their non-trivial magnetic field dependences point to magnetic-field-induced hybridization of electron subbands.Comment: Major changes, added one more figure, the latest version to be published in JETP Let

Opening an energy gap in an electron double layer system at integer filling factor in a tilted magnetic field

We employ magnetocapacitance measurements to study the spectrum of a double layer system with gate-voltage-tuned electron density distributions in tilted magnetic fields. For the dissipative state in normal magnetic fields at filling factor $\nu=3$ and 4, a parallel magnetic field component is found to give rise to opening a gap at the Fermi level. We account for the effect in terms of parallel-field-caused orthogonality breaking of the Landau wave functions with different quantum numbers for two subbands.Comment: 4 pages, 4 figures included, to appear in JETP Letter

Electrical stimulation alleviates depressive-like behaviors of rats: investigation of brain targets and potential mechanisms

Deep brain stimulation (DBS) is a promising therapy for patients with refractory depression. However, key questions remain with regard to which brain target(s) should be used for stimulation, and which mechanisms underlie the therapeutic effects. Here, we investigated the effect of DBS, with low- and high-frequency stimulation (LFS, HFS), in different brain regions (ventromedial prefrontal cortex, vmPFC; cingulate cortex, Cg; nucleus accumbens (NAc) core or shell; lateral habenula, LHb; and ventral tegmental area) on a variety of depressive-like behaviors using rat models. In the naive animal study, we found that HFS of the Cg, vmPFC, NAc core and LHb reduced anxiety levels and increased motivation for food. In the chronic unpredictable stress model, there was a robust depressive-like behavioral phenotype. Moreover, vmPFC HFS, in a comparison of all stimulated targets, produced the most profound antidepressant effects with enhanced hedonia, reduced anxiety and decreased forced-swim immobility. In the following set of electrophysiological and histochemical experiments designed to unravel some of the underlying mechanisms, we found that vmPFC HFS evoked a specific modulation of the serotonergic neurons in the dorsal raphe nucleus (DRN), which have long been linked to mood. Finally, using a neuronal mapping approach by means of c-Fos expression, we found that vmPFC HFS modulated a brain circuit linked to the DRN and known to be involved in affect. In conclusion, HFS of the vmPFC produced the most potent antidepressant effects in naive rats and rats subjected to stress by mechanisms also including the DRN.postprin