Update of High Resolution (e,e'K^+) Hypernuclear Spectroscopy at Jefferson Lab's Hall A

Updated results of the experiment E94-107 hypernuclear spectroscopy in Hall A of the Thomas Jefferson National Accelerator Facility (Jefferson Lab), are presented. The experiment provides high resolution spectra of excitation energy for 12B_\Lambda, 16N_\Lambda, and 9Li_\Lambda hypernuclei obtained by electroproduction of strangeness. A new theoretical calculation for 12B_\Lambda, final results for 16N_\Lambda, and discussion of the preliminary results of 9Li_\Lambda are reported.Comment: 8 pages, 5 figures, submitted to the proceedings of Hyp-X Conferenc

Activation Cascading in Sign Production

In this study, we investigated how activation unfolds in sign production by examining whether signs that are not produced have their representations activated by semantics (cascading of activation). Deaf signers were tested with a picture-picture interference task. Participants were presented with pairs of overlapping pictures and named the green picture (target) while ignoring the red picture (distractor). In Experiment 1 we varied whether target and distractor pictures had similar signs. Signs were produced faster with sign-related picture pairs compared to unrelated picture pairs. The facilitation observed with sign-related pairs replicates the 1 obtained in speaking with sound-related pairs (e.g., bed-bell), a finding cited in support of cascading of activation. In Experiments 2A and 2B we focused on sign iconicity, anticipating that cascading of activation would lead to a facilitatory effect of iconicity. Consistent with this prediction, picture distractors with iconic signs induced faster responses. Furthermore, in Experiment 3, facilitation was found for iconic signs in picture naming. Altogether, our results reveal that cascading of activation is a fundamental aspect of language processing that is at play not only in speaking, but also in signing. Our results also help to define which signs are activated in sign production. (PsycINFO Database Record)

Thyroid surgery in geriatric patients: a literature review.

BACKGROUND: Thyroid disease is common in the elderly population. The incidence of hypothyroidism and multinodular goitre gradually increases with age. In view of a growth of aging population, we performed a literature review about the feasibility of thyroid surgery in the elderly. METHODS: We conducted a literature search in the PubMed database in September 2012 and all English-language publications on thyroidectomy in geriatric patients since 2002 were retrieved. The potential original articles mainly focusing on thyroidectomy in elderly patients were all identified and full texts were obtained and reviewed for further hand data retrieving. RESULTS: We retrieved five papers based on different primary end-point. Four were retrospective non randomized studies and one was prospective non randomized study. At last 65, 70, 75 and 80 years were used as an age cut-off. All studies evaluate the indications of thyroidectomy in geriatric patients, postoperative morbility and mortality. Only one study specifically assesses the rate of the rehospitalization after thyroidectomy among the elderly. CONCLUSIONS: Thyroid nodules are particularly important in elderly patients, as the incidence of malignancy increases and they are usually more aggressive tumors. An age of at least 70 years is an independent risk factor for complications after general surgery procedures. Thyroid surgery in patients aged 70 years or older is safe and the relatively high rate of thyroid carcinoma and toxic goiter may justify an aggressive approach. A programmed operation with a careful pre-operative evaluation and a risk stratification should make the surgical procedures less hazardous, specially in 80 years old patients with an high ASA score

Performance of the Two Aerogel Cherenkov Detectors of the JLab Hall A Hadron Spectrometer

We report on the design and commissioning of two silica aerogel Cherenkov detectors with different refractive indices. In particular, extraordinary performance in terms of the number of detected photoelectrons was achieved through an appropriate choice of PMT type and reflector, along with some design considerations. After four years of operation, the number of detected photoelectrons was found to be noticeably reduced in both detectors as a result of contamination, yellowing, of the aerogel material. Along with the details of the set-up, we illustrate the characteristics of the detectors during different time periods and the probable causes of the contamination. In particular we show that the replacement of the contaminated aerogel and parts of the reflecting material has almost restored the initial performance of the detectors.Comment: 18 pages, 9 Figures, 4 Tables, 44 Reference

Nonequilibrium phenomena in quantum many-body systems with long-range interactions

The focus of this thesis work is on the role of long-range interactions in the nonequilibrium coherent quantum dynamics. I have explored a number of settings in which long-range interactions allow for phenomena which do not possess a counterpart in equilibrium. The results contained in this thesis contribute to establish long-range interactions as a source of anomalous nonthermal behavior in quantum many-particle systems. In particular, the two parts of the thesis discuss two relative underlying mechanisms, which involve long-range interactions in different ways

Halla A JLaba nakon postizanja 12 GeV

An overview is presented of the planned physics program for JLab\u27s Hall A following the 12 GeV upgrade with emphasis on the equipment needed to achieve the desired experimental goals. Results of simulations of sample experiments with anticipated uncertainties are presented.Predstavlja se plan fizičkih istraživanja u Halli A JLaba nakon podizanja energije na 12 GeV, s naglaskom na potrebnu opremu za postizanje željenih eksperimentalnih ciljeva. Izlažu se ishodi simulacija nekih mjerenja s očekivanim pogreškama

Quark-Hadron Duality in Neutron (3He) Spin Structure

We present experimental results of the first high-precision test of quark-hadron duality in the spin-structure function g_1 of the neutron and $^3$He using a polarized 3He target in the four-momentum-transfer-squared range from 0.7 to 4.0 (GeV/c)^2. Global duality is observed for the spin-structure function g_1 down to at least Q^2 = 1.8 (GeV/c)^2 in both targets. We have also formed the photon-nucleon asymmetry A_1 in the resonance region for 3He and found no strong Q^2-dependence above 2.2 (GeV/c)^2.Comment: 13 pages, 3 figure