Direct and indirect effects of zooplankton on algal composition in in situ grazing experiments

To examine both direct and indirect effects of macrozooplankton on phytoplankton species in Lake Biwa, we conducted in situ grazer-gradient experiments under different nutrient levels in summer, when Daphnia galeata dominated, and in autumn, when Eodiaptomus japonicus dominated. The experiments revealed that grazing pressure on phytoplankton was highly dependent on zooplankton species composition. Smaller phytoplankton species such as Stephanodiscus carconensis were more grazed when D. galeata was abundant, whereas large colonial diatom species such as Aulacoseira granulata were preferentially grazed when E. japonicus dominated. In addition, indirect effect of macrozooplankton through nutrient regeneration was suggested, although the magnitude of nutrient regeneration effects seemed to differ between D. galeata and E. japonicus. Specifically, growth rates of Sphaerocystis schroeteri were stimulated more by E. japonicus than by D. galeata. Macrozooplankton also enhanced the growth rates of colonial cyanobacteria such as Microcystis incerta, probably through decreasing the density of microzooplankton grazers (ciliates and rotifers). The results suggest that the effects of large zooplankton on phytoplankton populations are species-specific and cannot be understood without consideration of changes in abundance of other components of plankton communities.     

The epidemiology of tuberculosis in Phuentsholing General Hospital: a six-year retrospective study

ABSTRACT: BACKGROUND: This study was carried out to describe the epidemiology and treatment outcomes of TB infection in Bhutan at Phuentsholing General Hospital (PGH). Retrospective analysis of TB data was carried out using data from the TB registry of PGH from 2004-2009. Comparisons were made between TB, clinical presentation, diagnosis, and outcomes amongst male and female. RESULTS: A total of 735 patients were analyzed, 12.4% (91) of whom were children ([less than or equal to]14 years). The highest cases was reported in 2009 (148), lowest in 2004 (93). Males and females were equally infected with TB. The median age was 25 years, (range 11 months - 98 years; IQR=20-35). Extra-pulmonary Tuberculosis (EPT) 62.6% (57) was the commonest form of TB in children. Pleural effusion was more common in males 62.8% (27) (p=0.013). Smear positive pulmonary tuberculosis (SPPT) 54.3% (207) (p=0.02) and treatment defaulted 84.2% (16) (p=0.004) was higher in males. However, transfer-in cases 57.0% (90) (p=0.036) and treatment outcome-failure 92.3% (12) (p=0.002) were more in females than males. The cure rate for SPPT was 69.0% (293) and unknown treatment outcome for all forms of TB was 11.2% (82). CONCLUSION: TB infection has increase over the study period; SPPT increased more than other two forms of TB. The majority of the TB patients were in the age group of 15-34 years. Males and females were equally infected with TB and children made up 12.4% of TB patients. The cure rate amongst SPPT was 69%, which is much lower that the national target of 85% set by National Tuberculosis Control Programme (NTCP). Further studies need to be undertaken to identify the risk factor for TB in the economically productive age group. There is a need for improvement in the services, recording and reporting so as to meet the target of cure rate of 85% in SPPT patients.     

Highly Efficient Perovskite Solar Cell Photocharging of Lithium Ion Battery Using DC–DC Booster

Solar cells become a viable energy source to charge lithium ion batteries. Here a simple and efficient photocharging design approach is demonstrated, where a promising low cost single junction solar cell such as perovskite solar cell or dye sensitized solar cell efficiently charges a Li₄Ti₅O₁₂‐LiCoO₂ Li‐ion cell using a DC–DC voltage boost converter. The converter boosts the low input voltage of a single junction solar cell to charge a lithium ion cell and offers advantages including maximum power point tracking of solar photovoltaics and overvoltage protection for the lithium ion cell. This is the first demonstration of this technology. This approach leads to the highest reported overall efficiency of 9.36% and average storage efficiency of 77.2% at 0.5 C discharge for a perovskite solar cell‐converter charging. The high efficiency for the perovskite solar cell‐converter charging is attributed to maximum power harvesting along with high power conversion efficiency of the perovskite solar cell and low potential polarization between the charge and discharge voltage plateaus for the Li₄Ti₅O₁₂‐LiCoO₂ Li‐ion cell.     

Spatial and temporal movement of the Bearded Vulture using GPS telemetry in the Himalayas of Nepal

This study addresses for the first time the movement patterns of the globally near-threatened Bearded Vulture Gypaetus barbatus in its most important stronghold, the high-altitude mountain ranges of Asia. Tracked individuals (n = 8) in the Annapurna Himalayan range (Nepal) foraged over a vast range of 60 715.9 km² and our results indicated age-class differences in the use of space. Territorial adults showed very small annual home-ranges (K90 = 150.3 km²), whereas immatures wandered extensively and covered vast ranges of the mountains (K90 = 23 930.8 km²). For adults and immatures, these values are notably larger than the other two studied populations in the world (Pyrenees and South Africa). This suggests that the studied Annapurna population might exhibit lower breeding density than in the Pyrenees or South Africa, possibly due to lower food availability.