Search

The harvesting of solar energy is gaining increasing attention as it is pollution free and is available in abundance. Various researches and experiments are being carried out to improve the efficiency of power conversion by altering the material of the photovoltaic panels, by incorporating tracking systems and by making use of Maximum Power Point Tracking (MPPT) algorithms. The conventional rigidly fixed solar panels limit their area of exposure to the sun during the entire day. The use of tracker increases the area of panel exposed to direct beam of the sun, thus increasing the power generated. MPPT algorithm tracks the maximum power point attained at all loads and extracts the power from the panel at that voltage. Despite the variations in the external environment, the power obtained from the panel is always maximum. This paper reviews various tracking methods and MPPT techniques to increase the energy harvesting capacity of the panel and in turn improve its efficiency.

Background Indications for placement of implantable cardioverter-defibrillators (ICD) and pacemakers have expanded, and traditional transvenous implantation may not be feasible in patients with aberrant anatomy or venous obstruction. In these settings, successful lead placement has required innovative surgical approaches. A case series of successful placement of these systems in challenging patients is presented. Methods A 2-year retrospective study of patients undergoing placement of minimally invasive epicardial pacing leads or ICD coils was performed. Results Eleven patients underwent minimally invasive surgical placement of leads or coils. None were converted to open sternotomy. One required extension to minianterior thoracotomy. Causes of intravenous placement failure included aberrant anatomy with failure to access coronary sinus in 9 and venous occlusion in 2. Four patients had previous operations through a median sternotomy. Procedures included left video-assisted thoracoscopic (VATS) placement of a left ventricular epicardial lead in 8, left VATS conversion to minianterior thoracotomy left ventricular epicardial lead placement in 1, left VATS placement of ICD coil in 1, subxiphoid placement of a right ventricular epicardial lead in 1, subxiphoid ICD coil in 2, and subcutaneous ICD coil placement in 3. Mean hospitalization was 4.6 days. Postoperative hypotension and pulmonary edema occurred in 27% of patients. No patients died. Conclusions Conventional transvenous lead implantation may be difficult or impossible in some patients with aberrant or occluded venous access. Novel surgical approaches with the use of minimally invasive procedures can establish optimally functional pacing and ICD systems without sternotomy and low associated morbidity.

Ang, A., Srivasthan, A., Md.-Zain, B. M., Ismail, M. R. B. (2012): Low Genetic Variability In The Recovering Urban Banded Leaf Monkey Population Of Singapore. Raffles Bulletin of Zoology 60 (2): 589-594, DOI: http://doi.org/10.5281/zenodo.5350757, {"references":["Ang, A., M. Ismail & R. Meier, 2010. Reproduction and infant pelage coloration of the banded leaf monkey in Singapore. Raffles Bulletin of Zoology, 58: 411-415.","Bayona-Bafaluy, M. P., R. Acin-Perez, J. C. Mullikin, J. S. Park, R. Moreno-Loshuertos, P. Hu, A. P Perez-Martos, P. Fernandez- Silva, Y. Bai & J. A, Enr quez, 2003 Revisiting the mouse mitochondrial DNA sequence. Nucleic Acids Research, 31: 5349-5355.","Brook, B. W., N. S. Sodhi & P. K. L. Ng, 2003. Catastrophic extinctions follow deforestation in Singapore. Nature, 424: 420-423.","Charpentier, M. J. E., C. V. Williams & C. M. Drea, 2008. Inbreeding depression in ring-tailed lemurs (Lemur catta): genetic diversity predicts parasitism, immunocompetence, and survivorship. Conservation Genetics, 9: 1605-1615.","Chasen, F. N., 1924. A preliminary account of the mammals of Singapore Island. Singapore Naturalist, 4: 76-86.","Chasen, F. N., 1940. A handlist of Malayan mammals. Bulletin of the Raffles Museum, 15: 1-209.","Edmands, S., 2007. Between a rock and a hard place: Evaluating the relative risks of inbreeding and outbreeding for conservation and management. Molecular Ecology, 16: 463-475.","Groves, C. P., 2001. Primate Taxonomy. Smithsonian Institution Press, Washington.","Hayasaka, K., T. Ishida, & S. Horai, 1991. Heteroplasmy and polymorphism in the major noncoding region of mitochondrial DNA in Japanese monkeys:Association with tandemly repeated sequences. Molecular Biology and Evolution, 8: 399-415.","IUCN, 1987. IUCN Position Statement on Translocation of Living Organisms: Introductions, Re-introductions and Re-stocking. http://intranet.iucn.org/webfiles/doc/SSC/SSCwebsite/Policy_ statements/IUCN_Position_Statement_on_Translocation_of_ Living_Organisms.pdf. (Accessed 7 Jul.2011).","Kalinowski, S. T., 2004. Counting alleles with rarefaction: Private alleles and hierarchical sampling designs. Conservation Genetics, 5: 539-543.","Lande, R. & G. Barrowclough, 1987. Effective population size, genetic variation and their use in population management. In: Soule, M. E. (ed.), Viable Populations for Conservation. Cambridge University Press, New York. Pp. 87-124.","Lim, K. K. P., R. Subaraj, S. H. Yeo, N. Lim, D. Lane & B. Y. H. Lee, 2008. Mammals. In: Davison, G. W. H., P. K. L. Ng & H. C. Ho (eds.), The Singapore Red Data Book: Threatened Plants and Animals of Singapore. The Nature Society, Singapore. P. 198.","Liu, Z. J., B. P. Ren, F. W. Wei, Y. C. Long, Y. L. Hao & M. Li, 2007. Phylogeography and population structure of the Yunnan snub-nosed monkey (Rhinopithecus bieti) inferred from mitochondrial control region DNA sequence analysis. Molecular Ecology, 16: 3334-3349.","Lo, M. C., H. M. Lee, M. W. Lin & C. Y. Tzen, 2005. Analysis of heteroplasmy in hypervariable region II of mitochondrial DNA in maternally related individuals. In: Wei, Y. H., H. M. Lee & C. Y. Hsu (eds.), Role of the Mitochondria in Human Aging and Disease: From Genes to Cell Signaling. Pp. 130-135.","Lopez, J. V., M. Culver, J. C. Stephens, W. E. Johnson & S. J. O'Brien, 1997. Rates of nuclear and cytoplasmic mitochondrial DNA sequence divergence in mammals. Molecular Biology and Evolution, 14: 277-286.","Lutz, S., H. J. Weisser, J. Heizmann & S. Pollak, 2000. Mitochondrial heteroplasmy among maternally related individuals.International Journal of Legal Medicine, 113: 155-161.","McDonald, M. & H. Hamilton, 2010. Phylogeography of the Angolan black and white colobus monkey, Colobus angolensis palliatus, in Kenya and Tanzania. American Journal of Primatology, 72: 715-724.","Md.-Zain, B. M., J. C. Morales, M. N. Hasan, J. Abdul, M. Lakim, J. Supriatna & D. J. Melnick, 2008. Is Presbytis a distinct monophyletic genus: Inferences from mitochondrial DNA sequences. Asian Primates Journal, 1: 26-36.","Meier, R., S. Kwong, G. Vaidya & P. K. L. Ng, 2006. DNA barcoding and taxonomy in Diptera: A tale of high intraspecific variability and low identification success. Systematic Biology, 55: 715-728.","Meijaard, E. & C. P. Groves, 2004. The biogeographical evolution and phylogeny of the genus Presbytis. Primate Report, 68: 71-90.","Meyer, D., IrD. Rinaldi, H. Ramlee, D. Perwitasari-Farajallah, J. K. Hodges & C. Roos, 2011. Mitochondrial phylogeny of leaf monkeys with implications for taxonomy and conservation. Molecular Phylogenetics and Evolution, 59: 311-319.","Munshi-South, J. & H. Bernard, 2011. Genetic diversity and distinctiveness of the proboscis monkeys (Nasalis larvatus) of the Klia Peninsula, Sabah, Malaysia. Journal of Heredity, 102: 342-346.","Ng, P. K. L., R. T. Corlett & H. T. W. Tan, 2011. Singapore Biodiversity: An Encyclopedia of the Natural Environment and Sustainable Development. The Nature Society, Singapore. 496 pp.","Njiman, V., T. Geissman & E. Meijaard, 2008. Presbytis femoralis ssp. femoralis. In: IUCN, 2011. IUCN Red List of Threatened Species. Version 2011.1. www.iucnredlist.org.","Pan, D., H.-X. Hu, S.-J. Meng, Z.-M. Men, Y.-X. Fu & Y.-P. Zhang, 2009. A high polymorphism level in Rhinopithecus roxellana. International Journal of Primatology, 30: 337-351.","Pitra, C., C. Huttche & C. Niemitz, 1995. Population viability assessment of the banded leaf monkey in Singapore. Primate Report, 42: 47-59.","Schwarz, M. & J. Vissing, 2002. Paternal inheritance of mitochondrial DNA. The New England Journal of Medicine, 347: 576-580.","Spielman, D., B. W. Brook, D. A. Briscoe & R. Frankham, 2004. Does inbreeding and loss of genetic diversity decrease disease resistance? Conservation Genetics, 5: 439-448.","Sterner, K. N., R. L. Raaum, Y.-P. Zhang, C.-B. Stewart & T. R. Disotell, 2006. Mitochondrial data support an odd-nosed colobine clade. Molecular Phylogenetics and Evolution, 40: 1-7.","Viggers, K. L., D. B. Lindenmayer & D. M. Spratt, 1993. The importance of disease in reintroduction programmes. Wildlife Research, 20: 687-698.","Vun, V. F., M. C. Mahani, M. Lakim,A. Ampeng & B. M. Md.-Zain, 2011. Phylogenetic relationships of leaf monkeys (Presbytis; Colobinae) based on cytochrome b and 12S rRNA genes. Genetics and Molecular Research, 10: 368-381.","Weeks, A., C. M. Sgro, A. G. Young, R. Frankham, N. J. Mitchell, K. A. Miller et al., 2011. Assessing the benefits and risks of translocations in changing environments:A genetic perspective. Evolutionary Applications, 4: 709-725.","Westemeier, R. L., J. D. Brawn, S. A. Simpson, T. L. Esker, R. W. Jansen, J. W. Walk, E. L. Kershner, 1998. Tracking the longterm decline and recovery of an isolated population. Science, 282(5394): 1695-1698.","Yang, C. M. & H. K. Lua, 1988. A report of a banded leaf monkey found dying near the Bukit Timah Nature Reserve. Pangolin, 1: 23.","Yang, C. M., K. Yong & K. K. P. Lim, 1990. Wild mammals of Singapore. In: Chou, L. M. & P. K. L. Ng (eds.), Essays in Zoology. Department of Zoology, National University of Singapore. Pp. 1-23."]}

To investigate the incidence of atrial fibrillation after successful radiofrequency ablation for typical atrial flutter (AFL) and to compare its incidence with that of a reference population from the Framingham Heart Study to determine whether atrial flutter is an independent predictor for development of atrial fibrillation.Medical records of 234 patients who underwent radiofrequency ablation for AFL between January 1, 2002, and June 30, 2006, were reviewed. Patients were excluded if they had a history of atrial fibrillation or sustained atrial arrhythmia other than AFL or if they had atrial tachyarrhythmias other than AFL that could be induced during electrophysiology study (133 total patients excluded). The remaining 101 patients who underwent successful radiofrequency ablation for AFL were monitored for new-onset atrial fibrillation.During the mean+/-SD follow-up period of 574+/-315 days, atrial fibrillation developed in 13 (12.9%) of 101 patients. Atrial fibrillation developed in 12 of these patients within 6 months of ablation. The cumulative event-free rates (95% confidence intervals) were 97% (94%-100%) at 1 month, 91% (87%-97%) at 3 months, and 86% (81%-94%) at 6 months. Compared with the general population, patients aged 50 to 79 years who had ablation had a significantly higher incidence of atrial fibrillation (50-59 years, P=.01; 60-69 years, P=.001; 70-79 years, P=.007).Our finding of atrial fibrillation in 12.9% of patients whose atrial flutter was successfully eradicated suggests that patients with atrial flutter are at increased risk of developing atrial fibrillation, especially within the first 6 months after ablation.