SU(3) Breaking Effects in Hyperon Semi-Leptonic Decays and the extraction of F and D

The analysis of hyperon semi-leptonic decay data is re-examined in the light of a recent suggestion that SU(3) symmetry breaking effects may be taken into account by applying a correction to the $F/D$ ratio obtained via naive linear extrapolation in the hyperon masses. Comparison is made with the physically better motivated approach of applying so-called centre-of-mass corrections. This study (including all available data) reveals certain short-comings of the former of the above treatments, highlights some interesting aspects of this type of analysis and attempts to pinpoint the decay data that might usefully be improved. A tantalising result of the SU(3) breaking analysis performed here is that the magnitude of recoil correction required by the data corresponds closely to that required for the standard explanation of the reduction of \gA from its SU(6) value of 5/3. We also comment on other recent suggestions for taking into account the effects of SU(3) breaking. Finally a few remarks are made on the relevance for predicting the flavour non-singlet contribution to the proton $g_1$ and the Ellis-Jaffe sum rule.Comment: 12 pages, latex, no figures. Removed extended ascii set characters in the source file that were being corrupted by some mailer

SU(3) Breaking in Hyperon Beta Decays: a Prediction for Xi^0 -> Sigma^+ e nu-bar

On the basis of a previous analysis of hyperon semi-leptonic decay data, a prediction is presented for g_1/f_1 in the Xi^0 -> Sigma^+ e nu-bar beta-decay. The analysis takes into account SU(3) breaking in this sector via the inclusion of mass-driven corrections. A rather precise measurement of the above channel by the KTeV experiment at Fermilab will shortly be available. Since the dependence on the SU(3) parameters, F and D, is identical to that of the neutron beta-decay, such a measurement will provide a rather stringent test of SU(3) and the models used to describe its violation in these decays. The prediction given here for the above decay is g_1/f_1=1.17, which leads to a rate of 0.80 x 10^6 s^-1 and thus a branching fraction of 2.3 x 10^-4.Comment: LaTeX, 7 pages, uses acromake, cite and topcapt packages. Non-printing extended ascii characters replaced plus minor correction

Der Einfluß von CCC und B-995 auf das Triebwachstum von Reben

In der vorliegenden Arbeit wurden Untersuchungen über die Wirkung der beiden Hemmstoffe 2-Chloräthyl-trimethylammoniumchlorid (CCC) und 2-2- Dimethylbemsteinsäuredehydrazid (B-995) auf das Triebwachstum von Reben durchgeführt.Die Wirkungsweise beider Substanzen auf das Trieblängenwachstum ist sortenspezifisch, von der Konzentration, der Dosis und dem wachstumsphysiologischen Alter abhängig. Während bei allen untersuchten Sorten eine quantitativ unterschiedliche Hemmung des Trieblängenwachstums nachzuweisen war, lassen sich die Sorten hinsichtlich der Reaktion auf B-995 in 3 Reaktionsgruppen zusammenfassen: a) Hemmung des Trieblängenwachstums: V. silvestris, Fosters White Seedling, Gutedel, Morio-Muskat, Portugieser, Riesling, Ruländer, Scheurebe, Siegfried, Silvaner, blauer Spätburgunder, Traminer sowie die Zuchtstämme B-7-2 und B-2-11.b) Keine oder eine nur sehr schwache Veränderung des Trieblängenwachstums nach Applikation von B-995; V. rupestris, G 157, Kober 5 BB, Müller-Thurgau sowie die Neuzuchten Aris, Deckerrebe, Vi. 5861, Gf. 1-23-16, Gf. 30n-9-129 und B-6-18.c) Förderung des Trieblängenwachstums; V. labrusca.Die Beeinflussung der Trieblängenzunahme - ob Förderung oder Hemmung beruht hauptsächlich auf einer Veränderung der Internodienlänge. Die Einwirkung auf die Nodienzahl ist gering.Die Hemmwirkung von CCC und B-995 auf das Triebwachstum folgt einer logarithmischen Funktion.Bei gemeinsamer Applikation von CCC und Gibberellinsäure (GS) wird die durch GS hervorgerufene Wachstumsstimulation bei Riesling weder im Langtag noch im Kurztag durch CCC verändert.Die möglichen Ursachen der Reaktionsvariabilität, namentlich die Wechselwirkungen mit endogenem Gibberellin und Auxin, werden diskutiert. Abschließend werden die sich für die Weinbaupraxis ergebenden Konsequenzen aufgeführt

Der Einfluß von CCC und B-9 auf die Substanzproduktion von Reben

In der vorliegenden Arbeit wurden Untersuchungen an bewurzelten Rebstecklingen mit CCC (2-Chloräthyl-trimethylammoniumchlorid) und B-9 (2,2-Dimethylbernsteinsäurehydrazid) auf das Pflanzengewicht und die Blattstruktur durchgeführt. Mit zunehmender Hemmung des Triebwachstums wird zunächst das Stengelgewicht und bei stärkerer Hemmung auch das Blattgewicht vermindert. Eine Veränderung des Wurzelgewichtes durch die Behandlung des Sprosses mit Hemmstoffen konnte nicht festgestellt werden. Der Wassergehalt des Sprosses wird nicht verändert.Durch CCC und B-9 werden die Oberflächenentwicklung reduziert und der Hartlaubcharakter erhöht

Gliotransmission modulates baseline mechanical nociception

Pain is a physiological and adaptive process which occurs to protect organisms from tissue damage and extended injury. Pain sensation beyond injury, however, is a pathological process which is poorly understood. Experimental models of neuropathic pain demonstrate that reactive astrocytes contribute to reduced nociceptive thresholds. Astrocytes release "gliotransmitters" such as D-serine, glutamate, and ATP, which is extracellularly hydrolyzed to adenosine. Adenosine 1 receptor activation in the spinal cord has anti-nociceptive effects on baseline pain threshold, but the source of the endogenous ligand (adenosine) in the spinal cord is unknown. In this study we used a transgenic mouse model in which SNARE-mediated gliotransmission was selectively attenuated (called dnSNARE mice) to investigate the role of astrocytes in mediating baseline nociception and the development of neuropathic pain. Under baseline conditions, immunostaining in the dorsal horn of the spinal cord showed astrocyte-specific transgene expression in dnSNARE mice, and no difference in expression levels of the astrocyte marker GFAP and the microglia marker Iba1 relative to wild-type mice. The Von Frey filament test was used to probe sensitivity to baseline mechanical pain thresholds and allodynia following the spared nerve injury model of neuropathic pain. DnSNARE mice exhibit a reduced nociceptive threshold in response to mechanical stimulation compared to wild-type mice under baseline conditions, but nociceptive thresholds following spared nerve injury were similar between dnSNARE and wild-types. This study is the first to provide evidence that gliotransmission contributes to basal mechanical nociception

Experiments to Find or Exclude a Long-Lived, Light Gluino

Gluinos in the mass range ~1 1/2 - 3 1/2 GeV are absolutely excluded. Lighter gluinos are allowed, except for certain ranges of lifetime. Only small parts of the mass-lifetime parameter space are excluded for larger masses unless the lifetime is shorter than ~ 2 10^{-11} (m_{gluino}/ GeV) sec. Refined mass and lifetime estimates for R-hadrons are given, present direct and indirect experimental constraints are reviewed, and experiments to find or definitively exclude these possibilities are suggested.Comment: 27 pp, latex with 1 uufiled figure, RU-94-35. New version amplifies discussion of some points and corresponds to version for Phys. Rev.

Differences and similarities in instant countertransference towards patients with suicidal ideation and personality disorders.

Previous findings showed that suicidal patients elicit mostly negative countertransference such as distress, hopelessness, feelings of inadequacy, and apprehension, and that a concurrent personality disorder is associated with more feelings of entrapment and mistreatment, among other adverse reactions. No studies were however conducted on instant countertransference (iCT), i.e., after a single encounter, for example in an emergency setting. We aimed to evaluate the impact of suicidal ideations, self-harm and presence of personality disorders on instant Countertransference (iCT). Caregivers rated their iCT with two validated and standardized questionnaires after a first emergency or outpatient consultation. Suicidal ideation, self-harm and personality disorders were tested as predictors for iCT in a multivariate and multilevel analysis. Thirty caregivers rated their iCT towards 321 patients. Personality disorders and suicidal ideation, but neither recent nor past history of self-harm, predicted iCT. Common iCT included tension, lack of self-confidence and feeling of being tied. iCT specifically associated with suicidal ideation included distress, lack of hope, confusion, and sense that the patient's life had little worth. In contrast, iCT towards patients with personality disorders suggested tension in the therapeutic relationship (low affiliation with patient, anger, disappointment, devaluation). Caregiver's characteristics were not considered in the analysis. Furthermore, while countertransference also includes unconscious phenomena, only conscious iCT was assessed. Patients with suicidal ideation and personality disorders elicit common but also specific negative iCT. Mental health institutions need to devote specific resources (such as clinical supervision and training) to help caregivers manage their iCT

Critical Analysis of Baryon Masses and Sigma-Terms in Heavy Baryon Chiral Perturbation Theory

We present an analysis of the octet baryon masses and the $\pi N$ and $KN$ $\sigma$--terms in the framework of heavy baryon chiral perturbation theory. At next-to-leading order, ${\cal O}(q^3)$, knowledge of the baryon masses and $\sigma_{\pi N}(0)$ allows to determine the three corresponding finite low--energy constants and to predict the the two $KN$ $\sigma$--terms $\sigma^{(1,2)}_{KN} (0)$. We also include the spin-3/2 decuplet in the effective theory. The presence of the non--vanishing energy scale due to the octet--decuplet splitting shifts the average octet baryon mass by an infinite amount and leads to infinite renormalizations of the low--energy constants. The first observable effect of the decuplet intermediate states to the baryon masses starts out at order $q^4$. We argue that it is not sufficient to retain only these but no other higher order terms to achieve a consistent description of the three--flavor scalar sector of baryon CHPT. In addition, we critically discuss an SU(2) result which allows to explain the large shift of $\sigma_{\pi N}(2M_\pi^2) - \sigma_{\pi N}(0)$ via intermediate $\Delta (1232)$ states.Comment: 18 pp, TeX, BUTP-93/05 and CRN-93-0

The Proton Spin and the Wigner Rotation

It is shown that in both the gluonic and strange sea explanations of the Ellis-Jaffe sum rule violation discovered by the European Muon Collaboration (EMC), the spin of the proton, when viewed in in its rest reference frame, could by fully provided by quarks and antiquarks within a simple quark model picture, taken into account the relativistic effect from the Wigner rotation.Comment: 13 latex page