Interaction Spectroscopy of a Two-component Mott Insulator

We prepare and study a two-component Mott insulator of bosonic atoms with two particles per site. The mapping of this system to a magnetic spin model, and the subsequent study of its quantum phases, require a detailed knowledge of the interaction strengths of the two components. In this work, we use radio frequency (RF) transitions and an on-site interaction blockade for precise, empirical determination of the interaction strengths of different combinations of hyperfine states on a single lattice site. We create a map of the interactions of the lowest two hyperfine states of $^7$Li as a function of magnetic field, including measurements of several Feshbach resonances with unprecedented sensitivity, and we identify promising regions for the realization of magnetic spin models

The independence of control structures in abstract programming systems

AbstractAn instance of a control structure is a mapping which takes one or more programs into a new program whose behavior is based on that of the original programs. An instance of a control structure is effective iff it is effectively computable. In order to study the interrelationships of control structures, . we consider abstract programming systems (numberings of the partial recursive functions) in which some control structures, effective or otherwise, are present, but others are not. This paper uses the techniques of recursive function theory, including recursion theorems and priority arguments to prove the independence of certain control structures in abstract programming systems. For example, we have obtained the following results. In effective numberings of the partial recursive functions, the one-one effective Kleene recursion theorem and the one-one effective (partial) if-then-else control structure are independent, but together, they yield all effective control structures. In any effective numbering, the effective Kleene form of the double recursion theorem yields all effective control structures

High-precision analysis of Feshbach resonances in a Mott insulator

We show that recent high-precision measurements of relative on-site interaction energies $\Delta U$ in a Mott insulator require a theoretical description beyond the standard Hubbard-model interpretation, when combined with an accurate coupled-channels calculation. In contrast to more sophisticated lattice models, which can be elaborate especially for parameter optimization searches, we introduce an easy to use effective description of $U$ valid over a wide range of interaction strengths modeling atomic pairs confined to single lattice sites. This concise model allows for a straightforward combination with a coupled-channels analysis. With this model we perform such a coupled-channels analysis of high-precision $^7$Li spectroscopic data on the on-site interaction energy $U$, which spans over four Feshbach resonances and provide an accurate and consistent determination of the associated resonance positions. Earlier experiments on three of the Feshbach resonances are consistent with this new analysis. Moreover, we verify our model with a more rigorous numerical treatment of the two atom system in an optical lattice

Therapeutic effect of Vitamin E in patients with primary osteoarthritis

INTRODUCTION: Osteoarthritis (OA) is a disease affecting articular cartilage, bone and soft tissue. It is the most common form of joint disease and one of the most frequent causes of physical impairment. It is a universal disorder affecting both sexes and all races. It is more common in women than in men and in women the disease prevalence increases with age. It commonly involves weight bearing joints like hip and knee. The knee is often affected especially in women. AIM OF THE STUDY: To study the disease modifying action of vitamin E (α- tocopherol) in patients with primary OA of the knee joint. OBJECTIVES: 1. To study the analgesic effect of Vitamin E in OA by measuring WOMAC index score. 2. To study the anti-inflammatory effect of Vitamin E by measuring joint circumference of the knee. 3. To study the antioxidant effect of Vitamin E by measuring serum malondialdehyde. 4. To study the disease modifying action of Vitamin E using radiograph of the knee joint. METHODOLOGY: This prospective study was done to assess the therapeutic effect of oral Vitamin E capsule in comparison with oral Diclofenac sodium tablet in patients suffering from primary OA of the knee joint. STUDY DESIGN: This study was an open, prospective, single blinded, parallel group, two arm, out patient randomized control study. STUDY CENTRE: Out patient department of Orthopedics, Stanley Medical College Hospital, Chennai. STUDY DURATION: This study was carried out from January 2007 to December 2007. 4 months for each patient. Active drug therapy was given for 2 months and follow up for the next 2 months. STUDY SUBJECTS: Patients attending the Orthopedic OPD of Stanley Medical College Hospital, Chennai. SAMPLE SIZE: 80 Patients. 40 Patients in each group. Inclusion Criteria: 1. Age 40 years and above, 2. Both sexes, 3. Patient with primary OA, 4. Duration of disease < 3 months, 5. Patient with radiological changes of OA. Exclusion Criteria: 1. Secondary OA, 2. Hypertension, 3. Drug allergy, 4. Renal and liver disease, 5. Bleeding disorder, 6. Patients already on treatment for OA. RESULTS: Results of the comparative study of Vitamin E (E Group) and diclofenac sodium (D Group) were analysed statistically by student independent t test and chi square test. P < 0.05 was considered significant. A total of 85 patients were enrolled in the study. 81 patients completed the study. There were 4 drop outs, the reason for this was not known. CONCLUSION: In conclusion, this study provides evidence that free radicals are a major etiological factor for chondrocyte damage in OA. Oral vitamin E therapy, by inhibiting lipid peroxidation and nitric oxide formation is shown to have analgesic, anti-inflammatory and disease modifying action in addition to its anti-oxidant effect. Therefore, vitamin E therapy can be considered as a novel and safer alternative to NSAIDs in the treatment of primary OA

THE ANTIOXIDANT ROLE OF α-TOCOPHEROL IN THE NUTRITION

The role of the lipid-soluble antioxidant α-tocopherol (vitamin E) in the nutrition of African catfish (Clarias gariepinus Burchell) has been investigated with respect to effects on growth, certain indices of health and prevention of tissue lipid peroxidation. Although juvenile C. gariepinus were not found to show an immediate dependency on vitamin E for growth, even during rapid growth stages, a minimum requirement of α-tocopherol based on the prevention of hepatic lipid peroxidation was established at 30-40 mg α-tocopherol per kg dry diet. This is in line with published values for numerous cultured fish species. Tissue α-tocopherol accretion was found to be dependent on dietary dose of the vitamin (supplied as all-rac-α-tocopheryl acetate) and, with the exception of blood-plasma, increased tissue tocopherol status resulted in increased stability against lipid peroxidation. Assessment of iron-ascorbate induced peroxidation (as TBARS) revealed that feeding catfish with diets containing a-tocopherol at several times the currently supplemented level, improved the stability of catfish muscle and this has fillet quality implications. Similarly, heightened fillet vitamin E content resulted in lower moisture exudation from previously frozen fillets, thus demonstrating the role of a-tocopherol in the maintenance of membrane integrity. Oxidation of dietary oils and elevated ingestion of iron were found to be antagonistic of tissue vitamin E concentration. Consumption of feed containing rancid oil had marked effects on tissue fatty acid composition and these effects were modulated by increased intake of α-tocopheryl acetate. In catfish fed diets containing similar amounts of ascorbate, a higher α-tocopherol supplement marginally improved ascorbate retention indicating a possible sparing of vitamin C by vitamin E. The present work will contribute significantly to the understanding of antioxidant nutrition in this poorly researched cultured species. Furthermore, these investigations have improved and strengthened the database of knowledge accumulated within the field of nutrition of finfish.Department of Nutrition, University College Cork, Cork, Eir

Microstructural and metabolic changes in the brains of concussed athletes

Les commotions cérébrales ont longtemps été considérées comme une blessure ne comportant que peu ou pas de conséquences. Cependant, la mise à la retraite forcée de plusieurs athlètes de haut niveau, liée au fait d'avoir subi des commotions cérébrales multiples, a porté cette question au premier plan de la culture scientifique et sportive. Malgré la sensibilisation croissante du public et la compréhension scientifique accrue des commotions cérébrales, il reste encore beaucoup d’inconnus au sujet de ces blessures. En effet, il est difficile de comprendre comment cette atteinte peut avoir des effets si profonds malgré le fait qu’elle n’entraîne apparemment pas de conséquences physiques apparentes lorsque les techniques traditionnelles d’imagerie cérébrale sont utilisées. Les techniques de neuroimagerie fonctionnelle ont cependant contribué à répondre aux nombreuses questions entourant les conséquences des commotions cérébrales ainsi qu'à accroître la compréhension générale de la physiopathologie de commotions cérébrales. Bien que les techniques de base telles que l'imagerie structurelle comme les scans TC et IRM soient incapables de détecter des changements structurels dans la grande majorité des cas (Ellemberg, Henry, Macciocchi, Guskiewicz, & Broglio, 2009; Johnston, Ptito, Chankowsky, & Chen, 2001), d'autres techniques plus précises et plus sensibles ont été en mesure de détecter avec succès des changements dans le cerveau commotionné. Des études d’IRM fonctionelle ont entre autres établi une solide relation entre les altérations fonctionnelles et les symptômes post-commotionels (Chen, Johnston, Collie, McCrory, & Ptito, 2007; Chen et al., 2004; Chen, Johnston, Petrides, & Ptito, 2008; Fazio, Lovell, Pardini, & Collins, 2007). Les mesures électrophysiologiques telles que les potentiels évoqués cognitifs (ERP) (Gaetz, Goodman, & Weinberg, 2000; Gaetz & Weinberg, 2000; Theriault, De Beaumont, Gosselin, Filipinni, & Lassonde, 2009; Theriault, De Beaumont, Tremblay, Lassonde, & Jolicoeur, 2010) et la stimulation magnétique transcrânienne ou SMT (De Beaumont, Brisson, Lassonde, & Jolicoeur, 2007; De Beaumont, Lassonde, Leclerc, & Theoret, 2007; De Beaumont et al., 2009) ont systématiquement démontré des altérations fonctionnelles chez les athlètes commotionnés. Cependant, très peu de recherches ont tenté d'explorer davantage certaines conséquences spécifiques des commotions cérébrales, entre autres sur les plans structural et métabolique. La première étude de cette thèse a évalué les changements structurels chez les athlètes commotionnés à l’aide de l'imagerie en tenseur de diffusion (DTI) qui mesure la diffusion de l'eau dans la matière blanche, permettant ainsi de visualiser des altérations des fibres nerveuses. Nous avons comparé les athlètes commotionnés à des athlètes de contrôle non-commotionnés quelques jours après la commotion et de nouveau six mois plus tard. Nos résultats indiquent un patron constant de diffusion accrue le long des voies cortico-spinales et dans la partie du corps calleux reliant les régions motrices. De plus, ces changements étaient encore présents six mois après la commotion, ce qui suggère que les effets de la commotion cérébrale persistent bien après la phase aiguë. Les deuxième et troisième études ont employé la spectroscopie par résonance magnétique afin d'étudier les changements neurométaboliques qui se produisent dans le cerveau commotionné. La première de ces études a évalué les changements neurométaboliques, les aspects neuropsychologiques, et la symptomatologie dans la phase aiguë post-commotion. Bien que les tests neuropsychologiques aient été incapables de démontrer des différences entre les athlètes commotionnés et non-commotionnés, des altérations neurométaboliques ont été notées dans le cortex préfrontal dorsolatéral ainsi que dans le cortex moteur primaire, lesquelles se sont avérées corréler avec les symptômes rapportés. La deuxième de ces études a comparé les changements neurométaboliques immédiatement après une commotion cérébrale et de nouveau six mois après l’atteinte. Les résultats ont démontré des altérations dans le cortex préfrontal dorsolatéral et moteur primaire dans la phase aiguë post-traumatique, mais seules les altérations du cortex moteur primaire ont persisté six mois après la commotion. Ces résultats indiquent que les commotions cérébrales peuvent affecter les propriétés physiques du cerveau, spécialement au niveau moteur. Il importe donc de mener davantage de recherches afin de mieux caractériser les effets moteurs des commotions cérébrales sur le plan fonctionnel.Concussions had long been considered an injury of little to no consequence. However, the forced retirement of several high profile athletes due to the impact of having suffered multiple concussions has pushed the issue to the forefront of scientific and sports culture alike. Despite the growing public awareness and the ever-expanding scientific understanding of concussions there is still much that remains unknown about these injuries. Indeed, understanding how an injury can have such profound effects, though mostly transient, without any apparent physical consequence continues to confound how concussions are conceptualized in research. Neuroimaging techniques have helped answer many of the questions surrounding the physical consequences of concussions on the brain as well as increasing the general understanding of the pathophysiology of concussions. While basic structural imaging techniques such as CT scans and MRI are unable to detect any structural changes in the vast majority of cases (Ellemberg, et al., 2009; Johnston, et al., 2001), other more precise and sensitive techniques have been able to successfully detect changes in the concussed brain. Functional MRI studies have further established a strong relationship between functional alterations and post-concussion symptoms (Chen, et al., 2007; Chen, et al., 2004; Chen, et al., 2008; Fazio, et al., 2007). Electrophysiological measures such as ERP (Gaetz, et al., 2000; Gaetz & Weinberg, 2000; Theriault, et al., 2009; Theriault, et al., 2010) and TMS (De Beaumont, Brisson, et al., 2007; De Beaumont, Lassonde, et al., 2007; De Beaumont, et al., 2009) have consistently demonstrated alterations in concussed athletes. However, there has been very little research that has attempted to further explore the specific structural and metabolic aspects of concussion. The first study assessed structural changes in concussed athletes using diffusion tensor imaging which measures water diffusion in white matter. We compared concussed athletes with non-concussed control athletes in the days immediately after injury and again six months later. Our results indicated a consistent pattern of increased diffusion along neural tracts of the cortical spinal tract and in the corpus callosum underlying motor cortex. Furthermore, these changes were still present six months after injury suggesting that the effects of concussion are persistent past the acute phase. The second and third studies employed magnetic resonance spectroscopy as a means of investigating the neurometabolic changes that occur in the concussed brain. The first of these studies investigated the neurometabolic changes, neuropsychological aspects, and symptomatology in the acute post-injury phase. While neuropsychological testing was unable to show differences between concussed and non-concussed athletes, neurometabolic alterations were noted in the dorsal lateral prefrontal cortex as well as in primary motor cortex which correlated with reported symptoms. The second study investigated neurometabolic changes immediately after concussion and again six months after injury. Results indicated alterations in the dorsolateral prefrontal and primary motor cortices in the acute post-injury phase, but only those in primary motor cortex persisted to the six month time point

Exploring linear size-change terminating programs

Ph.DDOCTOR OF PHILOSOPH