1,028 research outputs found
Bottom-Tau Yukawa Unification in the Next-to-Minimal Supersymmetric Standard Model
We discuss the unification of the bottom quark and tau lepton Yukawa
couplings within the framework of the next-to-minimal supersymmetric standard
model. We compare the allowed regions of the - plane to those
in the minimal supersymmetric standard model, and find that over much of the
parameter space the deviation between the predictions of two models is small,
and nearly always much less than the effect of current theoretical and
experimental uncertainties in the bottom quark mass and the strong coupling
constant. However over some regions of parameter space top-bottom Yukawa
unification cannot be achieved. We also discuss the scaling of the light
fermion masses and mixing angles, and show that to within current uncertainties
the results of recent texture analyses performed for the minimal model also
apply to the next-to-minimal model.Comment: Southampton preprint SHEP 93/94-15, This is a latex file with
postscript figures attached to the end of the documen
Albert algebras over curves of genus zero and one
Albert algebras and other Jordan algebras are constructed over curves of
genus zero and one, using a generalization of the Tits process and the first
Tits construction due to Achhammer.Comment: 37 page
A Midwest School District’s Implementation Process Of A New Teacher Evaluation Model
The purpose of this study was to test the effectiveness of the implementation of the Marzano Teacher Evaluation Framework (MTEF) in a Midwest school district. The study used quantitative methods to examine the process used to bring about change in the school district’s teacher evaluation model. The researcher examined teacher and administrator perceptions regarding change, professional development, instructional improvement, reliability, and overall satisfaction with ease of use of the MTEF model.
The researcher used data collected from one Midwest school district. The school district consisted of twelve elementary schools, four middle schools, and three high schools. A total of 682 teachers and 26 administrators were surveyed. Data was collected by way of an on-line survey. The survey included three sections. The first section contained three demographic questions. The second section consisted of five questions regarding the study’s research constructs: (a) change, (b) professional development, (c) instructional improvement, (d) reliability, and (e) overall satisfaction with the MTEF model’s ease of use. The final section consisted of 19 questions that aligned with the study’s research constructs. For each research construct, there were three to five questions. Data gathered from participants’ responses were analyzed and used to provide recommendations to other school districts and educators around the state and nation as they implement new teacher evaluation models
Heavy neutrino mass scale and quark-lepton symmetry
Assuming hierarchical neutrino masses we calculate the heavy neutrino mass
scale in the seesaw mechanism from experimental data on oscillations of solar
and atmospheric neutrinos and quark-lepton symmetry. The resulting scale is
around or above the unification scale, unless the two lightest neutrinos have
masses of opposite sign, in which case the resulting scale can be intermediate.Comment: 7 pages RevTex, without figures. Corrected version with more comment
The association of complement with common connective tissue diseases - a review
Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenA strong association has been found between complement and common connective tissue diseases, such as systemic lupus erythema and Henoch Schoenlein Purpura. This has led to the notion that the pathogenesis of such diseases may involve a defect in the safe disposal of immune complexes, which is mediated by complement. To bring further light on this subject, a sensitive assay was developed to measure the ability of serum to prevent immune precipitation. This assay was then employed to study various Icelandic patient groups, and a defect in this function of complement was found to be common in patients with systemic lupus erythematosus and systemic sclerosis. Partial deficiency in complement C4A (C4A Q0) can not account for this defect, as it was not observed in patients with diabetes, gluten-sensitive enteropathy or autoimmune thyroiditis, in which C4A Q0 is common. The defect is strongly correlated with anti-C1q antibodies. Further studies are needed to test the possible role of anti-C1q antibodies in the pathogenesis of immune complex disease.Sterk tengsl hafa greinst milli magnakerfis og algengra bandvefssjúkdóma, svo sem rauðra úlfa og Henoch Schönlein Purpura. Þetta hefur leitt til hugmynda um að galli í virkni magnakerfis geti átt þátt í meinferli slíkra sjúkdóma, og er þá einkum litið til hlutverks kerfisins í eyðingu mótefnafléttna. Til að varpa ljósi á málið var þróað próf sem mælir getu blóðvökva til að halda mótefnafléttum í lausn. Þessu prófi hefur verið beitt á ýmsa hópa íslenskra sjúklinga og reyndist gölluð meðhöndlun mótefnafléttna algeng í rauðum úlfum og herslismeini. Vantjáð afurð C4A-gens (C4A*Q0) nægir ekki til að skýra þennan galla því hann finnst ekki í sjúklingum með sykursýki, glútenóþol eða skjaldkirtilssjúkdóm, þrátt fyrir háa tíðni C4A*Q0 í þessum hópum. Gallinn hefur á hinn bóginn sterka fylgni við hækkuð mótefni gegn C1q. Frekari rannsókna er þörf til að skera úr um hvort mótefni gegn C1q geti átt þátt í meinþróun sjúkdómsin
Quadruple Yukawa Unification in the Minimal Supersymmetric Model
Predictions for m_t, tan beta, m_nu_tau are calculated for quadruple third
family t-b-tau-nu_tau Yukawa unified models in the MSSM. The renormalisation
group equations for the 3 families of the MSSM, including the right handed
neutrino, are presented. For right handed tau neutrino Majorana masses that are
bigger than 10^11 GeV, the tau neutrino mass is consistent with present
cosmological bounds. The m_t, tan beta predictions are approximately equivalent
to those in triple third family Yukawa unified models.Comment: 10 pages plain LaTex, uuencoded .epsf files in part 2. Revised
version has NO changes to content, merely changed format to .tex fil
CASES OF LARGE FORECAST ERRORS OVER ICELAND
Forty-eight hour numerical forecasts during a period of 5 years are studied with emphasis on cases of false alarms and missed windstorms at 850 hPa. The overall performance of the forecast system is very good. Windstorms from the southwest are very well predicted, there are a few false alarms in southeasterly winds and northeasterly windstorms tend to be underestimated by the forecast model. The false alarms are in many cases associated with fronts, where a slight shift of a position of the weather system in time may give a large difference in the forecasted and observed winds. Yet, the true value of the forecast may be high. We attribute an underestimation in the wind speed in northeasterly windstorms to non-resolved orography, leading to an underestimation of the corner effect SW-Iceland, and possibly to winds that are generated by a pressure gradient at the western side of the Iceland wake
CASES OF LARGE FORECAST ERRORS OVER ICELAND
Forty-eight hour numerical forecasts during a period of 5 years are studied with emphasis on cases of false alarms and missed windstorms at 850 hPa. The overall performance of the forecast system is very good. Windstorms from the southwest are very well predicted, there are a few false alarms in southeasterly winds and northeasterly windstorms tend to be underestimated by the forecast model. The false alarms are in many cases associated with fronts, where a slight shift of a position of the weather system in time may give a large difference in the forecasted and observed winds. Yet, the true value of the forecast may be high. We attribute an underestimation in the wind speed in northeasterly windstorms to non-resolved orography, leading to an underestimation of the corner effect SW-Iceland, and possibly to winds that are generated by a pressure gradient at the western side of the Iceland wake
STATISTICS OF FORECAST ERRORS AND OROGRAPHY
We have compared differences between radiosonde observations in SW-Iceland and 48 hour forecast by a numerical weather prediction model over a period of five years (2000-2004). Temperature and height of the pressure levels of 925, 850 and 500 hPa were compared in search for systematic errors. In the overall mean, the predictions have little error and very limited bias. There are however slight seasonal variations and indications of situations
where the model does relatively poorly. At 500 hPa there is a cold bias in the forecasts in late winter, but no such bias in the autumn and early winter. At the lowest level there is a tendency of a cyclonic bias in the forecasted wind direction in northeasterly winds and in westerly flow, there is a warm bias in the forecasts. Both of these systematic low-level errors are attributed to non-resolved orography; the bias in the wind direction is most likely due to an underestimation of the deviation of the flow by the mountains and the warm bias appears to be associated with an underestimation of the accumulation of low level cold air upstream of Iceland
STATISTICS OF FORECAST ERRORS AND OROGRAPHY
We have compared differences between radiosonde observations in SW-Iceland and 48 hour forecast by a numerical weather prediction model over a period of five years (2000-2004). Temperature and height of the pressure levels of 925, 850 and 500 hPa were compared in search for systematic errors. In the overall mean, the predictions have little error and very limited bias. There are however slight seasonal variations and indications of situations
where the model does relatively poorly. At 500 hPa there is a cold bias in the forecasts in late winter, but no such bias in the autumn and early winter. At the lowest level there is a tendency of a cyclonic bias in the forecasted wind direction in northeasterly winds and in westerly flow, there is a warm bias in the forecasts. Both of these systematic low-level errors are attributed to non-resolved orography; the bias in the wind direction is most likely due to an underestimation of the deviation of the flow by the mountains and the warm bias appears to be associated with an underestimation of the accumulation of low level cold air upstream of Iceland
- …