Study of the Decay $\Lambda_c \to \Lambda l^+ \nu_{l}

Using the CLEO II detector at CESR, we observe 500 $\Lambda l^+$ pairs consistent with the semileptonic decay $\Lambda_c \to \Lambda l^+ \nu_{l}$. We measure $\sigma (e^+ e^- \to \Lambda_c X) \dot {cal B}(\Lambda_c^+ \to \Lambda l \nu_{l}) =4.77 \pm 0.25 \pm 0.66$pb. Combining with the charm semileptonic width and the lifetime of the $\Lambda_c$, we also obtain ${\cal B}(\Lambda_c \to p K^- \pi^+)$. We find no evidence for $\Lambda l^+ \nu_{l}$ final states in which there are additional $\Lambda_c^+$ decay products. We measure the decay asymmetry parameter of $\Lambda_c \to \Lambda l^+ \nu_{l}$ to be $\alpha_{\Lambda_c} =-0.89\pm{^{0.17}_{0.11}}\pm{^{0.09}_{0.06}}.Comment: 18 pages uuencoded compressed postscript (process with uudecode then gunzip). hardcopies with figures can be obtained by sending mail to: [email protected]

Clarifying Survey Questions

Although comprehension is critical to the survey response process, much about it remains unknown. Research has shown that concepts can be clarified through the use of definitions, instructions or examples, but respondents do not necessarily attend to these clarifications. This dissertation presents the results of three experiments designed to investigate where and how to present clarifying information most effectively. In the first experiment, eight study questions, modeled after questions in major federal surveys, were administered as part of a Web survey. The results suggest that clarification improves comprehension of the questions. There is some evidence from that initial experiment that respondents anticipate the end of a question and are more likely to ignore clarification that comes after the question than before it. However, there is considerable evidence to suggest that clarifications are most effective when they are incorporated into a series of questions. A second experiment was conducted in both a Web and Interactive Voice Response (IVR) survey. IVR was chosen because it controlled for the effects of interviewers. The results of this experiment suggest that readers appear no more capable of comprehending complex clarification than listeners. In both channels, instructions were least likely to be followed when they were presented after the question, more likely to be followed when they were placed before the question, and most likely to be followed when they were incorporated into a series of questions. Finally, in a third experiment, five variables were varied to examine the use of examples in survey questions. Broad categories elicited higher reports than narrow categories and frequently consumed examples elicited higher reports than infrequently consumed examples. The implication of this final study is that the choice of categories and examples require careful consideration, as this choice will influence respondents' answers, but it does not seem to matter where and how a short list of examples are presented

Measurement of Orbitally Excited D-Mesons at CDF II

Measurement of Orbitally Excited D-Mesons at CDF II Igor V. Gorelov (For the CDF Collaboration) Talk given on behalf of the CDF Collaboration at the First Meeting of the APS Topical Group on Hadronic Physics, GHP 2004, 24-26 October 2004, FERMILAB. Results on the first measurement of orbitally excited neutral D-meson states, D*_2 and D_1, produced in hadron collisions at Tevatron are presented. Using data from the displaced track trigger, CDF II collects the largest world sample of these states in decay modes D*+ pi-, D+ pi-. Masses and widths of both states have been measured with precision better than or comparable to the world average.Comment: 6 pages, 5 figures, talk given on behalf of the CDF Collaboration at the First Meeting of the APS Topical Group on Hadronic Physics, GHP 2004, Oct 24-26,2004, Fermilab, Batavia, Illinoi

An alternative fit to Belle mass spectra for DD, D*D* and Lambda_C Lambda_c

Peaks observed by Belle in DD at 3.878 GeV and in D*D* at 4.156 GeV may be fitted by phase space multiplied by a form factor with an RMS radius of interaction 0.63 fm. The peak observed in Lambda_C Lambda_C at 4.63 GeV may be explained by Y(4660), multiplied by a corresponding form factor with RMS radius 0.94 fm.Comment: 3 pages, 1 figures Shorted version, conclusions unchange

New Results From CLEO and BES

Latest experimental results from BES in the charmonium mass region, and those from CLEO in the bottomonium and charmonium spectroscopy are reviewed.Comment: 12 pages, 12 figures, Presented at First Meeting of the APS Topical Group on Hadron Physics, Fermilab, Batavia, Illinois, Oct 24-26, 200

THE MEDIATING EFFECT OF SCHOOL CLIMATE ON THE RELATIONSHIP BETWEEN TEACHER COMMUNICATION BEHAVIOR AND STUDENT ENGAGEMENT

The purpose of this study was to determine the mediating effect of school climate on the relationship between teacher communication behavior and student engagement. Utilizing quantitative, non-experimental design via correlational technique, data were obtained from 300 respondents of the study who are students who belong to the senior high school department, particularly Grade levels 11 and 12 of the three national high schools under the division of Davao Del Sur in the province of Davao Del Sur. The researcher utilized a stratified random sampling technique and an online survey mode of data collection. The researcher also utilized the statistical tools mean, Pearson r, and Medgraph using Sobel z-test. From the results of the study, it was found that there is a high level of mean score for teacher communication behaviour and very high levels of mean scores for school climate and student engagement. Also, results revealed that there is a significant relationship between teacher communication behaviour and student engagement, a significant relationship between teacher communication behaviour and school climate and a significant relationship between school climate and student engagement. Further, it was revealed that there was full mediation on the effect of school climate on the relationship between teacher communication behaviour and student engagement. This implies that the teacher’s communication behaviour conveys the school climate