Gapless Singlet modes in the Kagome strips: A study through DMRG and strong coupling analysis

Recently Azaria et al have studied strips of the Kagome-lattice in the weak-coupling limit, where they consist of two spin-half chains on the outside weakly coupled to an array of half-integer spins in the middle. Using a number of mappings they have arrived at the interesting result that in this system all spin excitations are gapped but there are gapless spinless modes. Here we study these Kagome strips in the limit where the interchain couplings are comparable to the coupling to the middle spins by density matrix renormalization group and by a strong coupling analysis. In the limit when the coupling to the middle-spin dominates, the 5-spins of the unit-cell reduce to a single S=3/2 spin, and the overall system has well known gapless spin excitations. We study the phase transition from this phase to the weak-coupling phase. We also carry out a strong coupling analysis away from the S=3/2 limit, where the five-spin blocks have four degenerate ground states with S=1/2, which can be thought of as two spin and two pseudospin degrees of freedom. A numerical study of this strong coupling model also suggests a finite spin-gap.Comment: 4 pages, 4 PS figure

Depression after Traumatic Brain Injury

Background Depression is known to be common after traumatic brain injury (TBI) and associated with worse functional and psychosocial outcomes. However, there remains considerable uncertainty over the exact prevalence of the condition. Aims The aim of this study was to accurately assess the prevalence of post TBI depression and its changes over a period of one year. The associated demographic and injury features were also examined for possible association with risk of depression in the hope that those with higher susceptibility to depression may be identified. Methods The study population was a prospective cohort of TBI admissions to a teaching hospital emergency department over a two year period. Minimal exclusions were applied in order to recruit a representative TBI population who were then assessed in a specialist brain injury clinic at ten weeks and at one year post injury. Demographic and injury features were recorded to establish links with risk of depression which was recorded with a HADS (Hospital Anxiety and Depression Scale). Results Over a two year period, 774 individuals were recruited of whom 690 attended one year follow-up and 38 had died. Only 6% of the cohort was lost to follow-up after one year. The prevalence of depression at ten weeks was 56.3% [95% CI 52.8-59.8] and at one year 41.2% [95% CI 37.6-44.9] A multivariable analysis identified the independent predictors of depression; at ten weeks these were TBI severity, abnormal CT scan, past psychiatric history, alcohol intoxication at the time of injury, female gender and non-white ethnicity. At one year the independent predictors were; abnormal CT scan, past psychiatric history, alcohol intoxication at the time of injury and female gender. TBI severity was no longer significant. Features such as injury aetiology, social isolation, age, length of stay and medical comorbidity were not associated with depression risk. All other outcome measures in the study, including psychosocial function, symptom severity and global overall outcome showed very high correlations with depression. Discussion The prevalence of depression is very high after TBI and associated with a number of injury features. While the prevalence drops over a year it still remains considerably elevated. There is also evidence that features related to the injury itself, such as TBI severity, become less significant in long term outcome compared to the initial period. It is possible that other psychosocial features such as personality and coping mechanisms are more important in determining long term outcome than injury features such as severity and aetiology. Some population features have been identified that may allow targeting of susceptible populations for intervention. The close correlations between all 4 outcome measures including depression suggest that they might be measuring a similar construct of emotional distress. Future work will seek to reassess the prevalence of depression at three or five years as well as associated features, re-examining the relationship between various outcomes and use of interventions and treatments, especially in targeting at risk individuals

Giant intra-abdominal hydatid cysts with multivisceral locations

The disseminated intra-peritoneal hydatid disease is a very rare finding. A case of disseminated intra abdominal hydatid disease is presented along with a review of literature and various therapeutic modalitie

Water Use Efficiency and Evapotranspiration of Hybrid Napier (\u3cem\u3ePennisetum purpureum\u3c/em\u3e x \u3cem\u3eP. americanum\u3c/em\u3e) under Semi-Arid Indian Region

Napier bajra hybrid (Pennisetum glaucum x P. purpureum) is a highly valued for its abundant quality forage, round the year fodder availability, regenerative ability and suitability to silage and hay making. It yields upto 110-120 t/ha fresh fodder as sole crop. Though, it requires moist regimes for optimum growth, but it can withstand drought for a short spell and regenerate with rains. It contains 8.7-10.2 % crude protein, 28-30.5% crude fibre and 10-11.5 % ash on dry matter basis (Agrawal et al., 2001). The hybrid napier has wider adaptability and is grown all over the country, particularly in milk shed area of Gujrat, Maharashtra and north and central India. Estimation of evapotranspiration (ET) as a function of crop stages is important in determining crop water use for efficient irrigation management. Evapotranspiration loss and the rate of evapotranspiration at different cutting stages indicate the amount of water required at different growth periods for its satisfactory growth and optimum production. Few results in measurement of evapotranspiration and water use efficiency of fodder crops are available (Alvarez and Quiroga, 1992; Pradeep Behari et al., 2003). The water stress in the plant can be quantified by actual evapotranspiration rate, as the level of evapotranspiration is related to the evaporative demand of the air (Doorenbos and Kassam, 1979). However, the information on these aspects for hybrid napier is lacking. In present study we estimate, the water use efficiency and evapotranspiration of the hybrid napier in central India

Sustainable Operations in Reverse Supply Chain of Shipbuilding Business - Benefits of Green Practices

Sustainable operations have become extremely important for survival of present day shipbuilding business wherein triple bottom-line criteria – profit, planet and people, needs to be satisfied. This paper discusses about recapturing value at the end-of-life of a ship and reintroducing it to the value chain through reverse supply chain channel, thereby reducing environmental impact and also benefitting humans and ecology.  It also describes about the advantages of recycling ship vis-à-vis scrapping it in terms of environmental and human impact

Effect of Sugar Promoters on Biomass Yield and Sugar Content of Napier Bajra Hybrids

In India deficiency of green fodder is estimated to the tune of 35.7% and this difference is likely to increase in coming period due to possible decrease in acreage under fodder crops as the cultivated land is being utilized for urbanization and other industrial uses. In tropical countries like India, crop residues from cultivated crops and grasses (mainly monsoon grasses) constitute the basal diet of livestock. But the nutritive value of these grasses is low (protein and digestibility) than the fodder crops and even in green stage is able only to meet the maintenance requirement of animals. A conservative estimate is that around 220 million tones of surplus green herbages is available during flush season of monsoon and can be conserved through ensiling. But due to the low DM (dry matter) and WSC (water soluble carbohydrate) content (2-4%) in such tropical grasses, they results in poor fermentation of freshly cut materials under anaerobic environment of ensiling. A minimum of 7-8% of water-soluble carbohydrate is needed to initiate the fermentation process. Hence, there is a need to improve in the quality of grasses even to conserve them as silage. The research efforts put forth by animal nutritionist to conserve these grasses as silage were not successful mainly due to their low water soluble carbohydrate contents. The use of chemicals to increase immature internodal sucrose levels in sugarcane has been made in some parts of the world. In forages, such efforts may solve the issue of conservation of monsoon grass as hay. Keeping in the view, an attempt has been made to explore the possibility of improving the sugar content of BN Hybrid grass