DMRG Study of Critical Behavior of the Spin-1/2 Alternating Heisenberg Chain

We investigate the critical behavior of the S=1/2 alternating Heisenberg chain using the density matrix renormalization group (DMRG). The ground-state energy per spin and singlet-triplet energy gap are determined for a range of alternations. Our results for the approach of the ground-state energy to the uniform chain limit are well described by a power law with exponent p=1.45. The singlet-triplet gap is also well described by a power law, with a critical exponent of p=0.73, half of the ground-state energy exponent. The renormalization group predictions of power laws with logarithmic corrections can also accurately describe our data provided that a surprisingly large scale parameter is present in the logarithm.Comment: 6 pages, 4 eps-figure

Dental Caries, Fluorosis, and Fluoride Exposure in Michigan Schoolchildren

This study relates the prevalence of caries and fluorosis among Michigan children, residing in four different areas, to the various concentrations of F in the communities' water supplies. Demographic information, details of F history, and dental attendance data were collected by a questionnaire form filled out by parents. Children ages six to 12 were screened for caries by means of the NIDR criteria and for fluorosis by means of the TSIF index. Results pertain only to continuous residents and the permanent dentition. The prevalence of both caries and fluorosis was significantly associated with the F concentration in the community water supply. Approximately 65% of all children were caries-free, ranging from 55.1 % in fluoride-deficient Cadillac to 73.7% in Redford (1. 0 ppm F). About 36% of all children had dental fluorosis, ranging from 12.2 in Cadillac to 51.2 in Richmond (1.2 ppm). All of the fluorosis was very mild. From logistic regression, the prevalence of caries was significantly associated with age, dental attendance, and the use of a water supply fluoridated at 1.0 ppm. The odds of experiencing fluorosis increased at every F level above the baseline (Cadillac), with the use of topical F rinses, and with age. Results suggest that children in the four communities may be ingesting a similar level of F from sources such as dentifrices, dietary supplements, and professional applications, but the factor that differentiates them with respect to the prevalence of caries and fluorosis is the F concentration in the community water supply.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66926/2/10.1177_00220345880670050101.pd

Relationship between protein O -linked glycosylation and insulin-stimulated glucose transport in rat skeletal muscle following calorie restriction or exposure to O -(2-acetamido-2-deoxy-d-glucopyranosylidene)amino- N -phenylcarbamate

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65566/1/j.1365-201X.2004.01403.x.pd

Phenotypic Diversity for Seed Mineral Concentration in North American Dry Bean Germplasm of Middle American Ancestry

Dry bean (Phaseolus vulgaris L.) seeds are a major protein, carbohydrate, and mineral source in the human diet of peoples in multiple regions of the world. Seed mineral biofortification is an ongoing objective to improve this important food source. The objective of this research was to assess the seed mineral concentration of five macroelements and eight microelements in a large panel (n = 277) of modern race Durango and race Mesoamerica genotypes to determine if variability existed that could be exploited for targeted seed biofortification. Varieties that derive from these races are found in many diets throughout the world. The panel was grown in replicated trials under typical production conditions in the major bean growing regions of the United States, and a subset of the panel was also grown in replicated trials at three locations under control and terminal drought conditions. Except for K, seed mineral concentrations were higher for race Mesoamerica genotypes. Significantly higher seed concentrations for the majority of the minerals were observed for white-seeded genotypes and race Durango genotypes with the now preferred indeterminate, upright growth habit. Modern genotypes (since 1997) had equal or increased mineral concentrations compared with older genotypes. Drought affected mineral content differentially, having no effect on the microelement content but increased Co, Fe, and Ni concentrations. The correlation of Ca and Mn concentrations suggests that these elements may share seed deposition mechanisms. The high heritability for seed mineral concentration implies that breeding progress can be achieved by parental selection from this panel

Workshop on the design and use of clinical trials with multiple endpoints, with a focus on prevention of RSV

A meeting held in Lisbon, Portugal, in February 2023 focused on critical aspects of clinical trial design for respiratory syncytial virus (RSV) preventative therapies. The meeting addressed two primary areas: enhancing the efficiency and success of randomized controlled trials (RCTs) for RSV preventative therapies and designing RCTs to better inform post-licensure decision-making. Topics included the selection of primary endpoints, innovative approaches to incorporating multiple endpoints and historical data, and the challenges and benefits of sequential trial designs. The discussion also touched on meta-regression models for obtaining more robust, context-specific estimates of vaccine efficacy. Overall, the meeting underscored the importance of balancing efficiency and robustness in RSV vaccine trial design, while recognizing the need for further discussions involving regulatory and advisory bodies

Multifragmentation of a very heavy nuclear system (II): bulk properties and spinodal decomposition

The properties of fragments and light charged particles emitted in multifragmentation of single sources formed in central 36AMeV Gd+U collisions are reviewed. Most of the products are isotropically distributed in the reaction c.m. Fragment kinetic energies reveal the onset of radial collective energy. A bulk effect is experimentally evidenced from the similarity of the charge distribution with that from the lighter 32AMeV Xe+Sn system. Spinodal decomposition of finite nuclear matter exhibits the same property in simulated central collisions for the two systems, and appears therefore as a possible mechanism at the origin of multifragmentation in this incident energy domain.Comment: 28 pages including 14 figures; submitted to Nucl. Phys.