Decays of Heavy Mesons

We present preliminary results for heavy to light transitions of pseudoscalar mesons, induced by the vector and tensor operators. This lattice study is performed in quenched approximation, by using the nonperturbatively improved Wilson action and operators. We also update the values of the heavy-light meson decay constants.Comment: LATT99(Heavy Quarks), 3 pages, 2 figure

Collecting genetic material from beef cattle (2005)

The beef cattle industry has long awaited the development of genetic tests to assist producers in breeding selection and management and to improve the marketability of cattle. Currently, there are only a handful of genetic tests commercially available for beef cattle. Beef producers interested in using genetic testing to improve their breeding stock need to know how to collect and store various genetic materials for testing.New February 2005 -- Extension website

Balancing the robustness and predictive performance of biomarkers.

Recent studies have highlighted the importance of assessing the robustness of putative biomarkers identified from experimental data. This has given rise to the concept of stable biomarkers, which are ones that are consistently identified regardless of small perturbations to the data. Since stability is not by itself a useful objective, we present a number of strategies that combine assessments of stability and predictive performance in order to identify biomarkers that are both robust and diagnostically useful. Moreover, by wrapping these strategies around logistic regression classifiers regularized by the elastic net penalty, we are able to assess the effects of correlations between biomarkers upon their perceived stability. We use a synthetic example to illustrate the properties of our proposed strategies. In this example, we find that: (i) assessments of stability can help to reduce the number of false-positive biomarkers, although potentially at the cost of missing some true positives; (ii) combining assessments of stability with assessments of predictive performance can improve the true positive rate; and (iii) correlations between biomarkers can have adverse effects on their stability and hence must be carefully taken into account when undertaking biomarker discovery. We then apply our strategies in a proteomics context to identify a number of robust candidate biomarkers for the human disease HTLV1-associated myelopathy/tropical spastic paraparesis (HAM/TSP)

HUBUNGAN PANJANG-BOBOT, POLA PERTUMBUHAN DAN FAKTOR KONDISI IKAN PELAGIS KECIL DI PERAIRAN SUKABUMI DAN LEBAK

Perairan Lebak, Banten dan Sukabumi, Jawa Barat yang merupakan bagian dari WPPNRI 573 adalah daerah penangkapan ikan pelagis. Kajian mengenai hubungan panjang-bobot serta faktor kondisi ikan pelagis kecil di kedua daerah tersebut masih sangat terbatas. Penelitian ini dilakukan untuk menganalisis hubungan panjang-bobot, pola pertumbuhan dan faktor kondisi ikan pelagis kecil di perairan Sukabumi dan Lebak. Ikan pelagis kecil yang dijadikan sampel meliputi kembung lelaki (Rastrelliger kanagurta) dan layang (Decapterus macarellus). Sampel ikan diperoleh dari tiga pendaratan ikan yaitu PPI Binuangeun, PPN Palabuhanratu dan PPI Ciwaru dari bulan Juli-Desember 2022. Persamaan hubungan panjang-bobot ikan kembung lelaki adalah W=0,0000075.L3,125 (R2 = 0,93), sedangkan pada ikan layang adalah W=0,0000059.L3,136 (R2 = 0,96). Pola pertumbuhan ikan kembung lelaki dan ikan layang diperoleh alometrik positif. Hasil kondisi relatif (Kn) ikan kembung lelaki berada pada kisaran 0,91-1,06, nilai paling rendah ditemukan pada bulan Agustus dan nilai paling tinggi ditemukan pada bulan Desember. Sementara itu nilai faktor kondisi relatif ikan layang berkisar antara 0,87-1,06, dengan nilai terendah saat bulan Juli dan tertinggi saat bulan Desember. Pola pertumbuhan alometrik positif dan faktor kondisi yang tinggi mengindikasikan bahwa status ikan kembung lelaki dan ikan layang di perairan Sukabumi dan Lebak berada dalam kondisi yang baik

Time-resolved spectroscopy of multi-excitonic decay in an InAs quantum dot

The multi-excitonic decay process in a single InAs quantum dot is studied through high-resolution time-resolved spectroscopy. A cascaded emission sequence involving three spectral lines is seen that is described well over a wide range of pump powers by a simple model. The measured biexcitonic decay rate is about 1.5 times the single-exciton decay rate. This ratio suggests the presence of selection rules, as well as a significant effect of the Coulomb interaction on the biexcitonic wavefunction.Comment: one typo fixe

The acquisition of inductive constraints

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Brain and Cognitive Sciences, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 197-216).Human learners routinely make inductive inferences, or inferences that go beyond the data they have observed. Inferences like these must be supported by constraints, some of which are innate, although others are almost certainly learned. This thesis presents a hierarchical Bayesian framework that helps to explain the nature, use and acquisition of inductive constraints. Hierarchical Bayesian models include multiple levels of abstraction, and the representations at the upper levels place constraints on the representations at the lower levels. The probabilistic nature of these models allows them to make statistical inferences at multiple levels of abstraction. In particular, they show how knowledge can be acquired at levels quite remote from the data of experience--levels where the representations learned are naturally described as inductive constraints. Hierarchical Bayesian models can address inductive problems from many domains but this thesis focuses on models that address three aspects of high-level cognition. The first model is sensitive to patterns of feature variability, and acquires constraints similar to the shape bias in word learning. The second model acquires causal schemata--systems of abstract causal knowledge that allow learners to discover causal relationships given very sparse data. The final model discovers the structural form of a domain--for instance, it discovers whether the relationships between a set of entities are best described by a tree, a chain, a ring, or some other kind of representation. The hierarchical Bayesian approach captures several principles that go beyond traditional formulations of learning theory.(cont.) It supports learning at multiple levels of abstraction, it handles structured representations, and it helps to explain how learning can succeed given sparse and noisy data. Principles like these are needed to explain how humans acquire rich systems of knowledge, and hierarchical Bayesian models point the way towards a modern learning theory that is better able to capture the sophistication of human learning.by Charles Kemp.Ph.D

Study on Food Habits of Moustached Thryssa (Thryssa Mystax) at Ujung Pangkah Waters, East Java

Moustached thryssa is one of an important fishery commodity in ujung pangkah waters. The study aimed toinvestigate food habits of the fish caught in the area. This study was conducted in ujung pangkah waters, gresik,east java using fish samples (n=76 males, n=119 females) collected during january to june 2006. Research resultshows that shrimps was a main food, bivalva and parts of crustacean were complementary food, while copepodsand pollychaeta were suplementary food both for male and female fish. Based on index of stomach contents, theindex was higher during january and april for male and female fish. Percentage of food of the fish variedaccording to size. According to simmilariy index, the main food of male and female fish was simmilar.

Nitrene transfer reactions by late transition metal complexes

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2007.Vita.Includes bibliographical references.This thesis presents nitrene transfer reactions that are catalyzed or mediated by late transition metal complexes. Sterically large, fluorinated supporting ligands are used to minimize potential side reactions. A new 1,10-phenanthroline ligand has been synthesized with 2,4,6-(CF3)3C6H2- groups in the 2- and 9-positions (1). A cationic copper(l) complex of 1 catalyzes nitrene transfer from N-(p-toluenesulfonylimino)phenyliodinane (PhlNTs) to the C-H bonds of 1,3-dimethoxybenzene in 63% yield. Altering the stoichiometry results in the formation of a different major product, N,N-bis(2',4'-dimethoxyphenyl)-p-toluenesulfonamide, in 33% yield. Treatment of a cationic copper(l) complex of 1 with p-nitrobenzenesulfonyl azide (NsN3) results in the formation of a rare mononuclear sulfonamido complex of copper(ll), 2. This complex is presumably formed via decomposition of a reactive sulfonimido complex of copper(lll). Although not a proficient nitrene transfer reagent to benzene, complex 2 is a precatalyst for nitrene transfer from NsN3 to benzene. Deprotonation of a palladium(ll) sulfonamido complex of 1 results in the formation of the first mononuclear sulfonimido complex of palladium,(cont.) 3. The sulfonimido ligand is bound in a K2-N,O chelate. This complex is a proficient nitrene transfer reagent to carbon monoxide, phosphines, and ethyl vinyl ether. A rhodium(lll) hydride chloride complex containing two N-heterocyclic carbene ligands, one of which is cyclometallated, is a convenient synthetic equivalent of a rhodium(l) chloride complex. Treatment of the rhodium(Ill) hydride with acetonitrile results in reductive elimination to form a rhodium(l) chloride complex. The chloride is readily abstracted by sodium azide to form a cationic rhodium(l) complex coordinated by two molecules of acetonitrile and containing an unbound azide. Upon exposure to UV light, this molecule undergoes cyclometallation to form a cationic rhodium(lll) hydride complex. The rhodium(lll) hydride chloride complex can be treated with oxygen to form a rhodium(lll) peroxide complex. The neutral peroxide complex has poor reactivity with trimethylphosphite and t-stilbene. However, a cationic rhodium peroxide complex oxidizes trimethylphosphite and t-stilbene at elevated temperatures.by Charles W. Hamilton.Ph.D

Multifocal Joint Osteonecrosis in Sickle Cell Disease

The purpose of this study was to evaluate the frequency of multifocal osteonecrosis in patients with sickle cell disease. Between 1980 and 1989, 200 patients with sickle cell disease were treated in our institution for osteonecrosis. The patient population consisted of 102 males and 88 females with a mean age of twenty-six years at the time of presentation (range, eighteen to thirty-five years) and was followed until the year 2005. This cohort of patients was follow-up during average 15 years (until the year 2005). Multifocal osteonecrosis was defined as a disease of 3 or more anatomic sites. At the time of presentation, 49 patients were identified as having multifocal osteonecrosis. At the most recent follow-up, 87 patients had multifocal osteonecrosis. So at the last follow up among these eighty-seven patients, the occurrence of osteonecrosis was 158 lesions of the proximal femur associated with 151 proximal humerus osteonecroses, thirty-three lateral femoral condyle osteonecroses, twenty-eight distal femoral metaphysis osteonecroses, twenty-seven medial femoral condyle osteonecroses, twenty-three tibial plateau osteonecroses, twenty-one upper tibial metaphysis osteonecroses and forteen ankle osteonecroses. The total number of osteonecrosis was 455 in these 87 patients. The epiphyseal lesions were more frequent than the metadiaphyseal lesions excepted in the proximal tibia (Table 3). In conclusion, in patients with sickle cell disease, the risk of multifocal osteonecrosis is very high. In patients with hip osteonecrosis, the other joints should be evaluated with radiograph and MRI if the joint is symptomatic. In patients with osteonecrosis of the knee, shoulder or ankle, the patients’ hip should be evaluated by radiographs or MRI, regardless of whether the hip is symptomatic