CDMS, Supersymmetry and Extra Dimensions

The CDMS experiment aims to directly detect massive, cold dark matter particles originating from the Milky Way halo. Charge and lattice excitations are detected after a particle scatters in a Ge or Si crystal kept at ~30 mK, allowing to separate nuclear recoils from the dominating electromagnetic background. The operation of 12 detectors in the Soudan mine for 75 live days in 2004 delivered no evidence for a signal, yielding stringent limits on dark matter candidates from supersymmetry and universal extra dimensions. Thirty Ge and Si detectors are presently installed in the Soudan cryostat, and operating at base temperature. The run scheduled to start in 2006 is expected to yield a one order of magnitude increase in dark matter sensitivity.Comment: To be published in the proceedings of the 7th UCLA symposium on sources and detection of dark matter and dark energy in the universe, Marina del Rey, Feb 22-24, 200

Black Hole Entropy Function, Attractors and Precision Counting of Microstates

In these lecture notes we describe recent progress in our understanding of attractor mechanism and entropy of extremal black holes based on the entropy function formalism. We also describe precise computation of the microscopic degeneracy of a class of quarter BPS dyons in N=4 supersymmetric string theories, and compare the statistical entropy of these dyons, expanded in inverse powers of electric and magnetic charges, with a similar expansion of the corresponding black hole entropy. This comparison is extended to include the contribution to the entropy from multi-centered black holes as well.Comment: LaTeX file, 196 pages, based on lectures given at various schools; v2: added appendix E containing analysis of the multiple D5-brane system, expanded discussion on duality orbits, other minor changes, references added; v3: equations (5.6.20) and (5.6.21) corrected; v4: minor corrections to equations (C.19), (C.20

Size Doesn't Matter: Towards a More Inclusive Philosophy of Biology

notes: As the primary author, O’Malley drafted the paper, and gathered and analysed data (scientific papers and talks). Conceptual analysis was conducted by both authors.publication-status: Publishedtypes: ArticlePhilosophers of biology, along with everyone else, generally perceive life to fall into two broad categories, the microbes and macrobes, and then pay most of their attention to the latter. ‘Macrobe’ is the word we propose for larger life forms, and we use it as part of an argument for microbial equality. We suggest that taking more notice of microbes – the dominant life form on the planet, both now and throughout evolutionary history – will transform some of the philosophy of biology’s standard ideas on ontology, evolution, taxonomy and biodiversity. We set out a number of recent developments in microbiology – including biofilm formation, chemotaxis, quorum sensing and gene transfer – that highlight microbial capacities for cooperation and communication and break down conventional thinking that microbes are solely or primarily single-celled organisms. These insights also bring new perspectives to the levels of selection debate, as well as to discussions of the evolution and nature of multicellularity, and to neo-Darwinian understandings of evolutionary mechanisms. We show how these revisions lead to further complications for microbial classification and the philosophies of systematics and biodiversity. Incorporating microbial insights into the philosophy of biology will challenge many of its assumptions, but also give greater scope and depth to its investigations

Postharvest evaluation of Colletotrichum gloeosporiodes f. sp. manihotis on cassava genotypes

The aim of this study was to evaluate the post-harvest survival of Colletotrichum gloeosporioides f. sp. manihotis on infected cassava materials. Infected stem cuttings from 5 cassava cultivars 88/01084, 88/01983, 91/00395, 91/00317 and 91/00052, incubated at 25±2°C for 8 months, showed a significant decrease in fungal survival amongst the cassava cultivars. At 8 months incubation fungal recovery was lowest below 10% among the infected cultivars. Cassava stakes, stored at humid conditions under tree shades for 16 months, showed a gradual decrease in fungal survival up to the 10th month, after which survival peaked again from the 12th up to the 16th month of storage. Survival of the fungus on soil significantly reduced with incubation time and at the 6th month of sampling, there was no recovery recorded for all the soils from the field plot sites. Burial of infected materials for 150 days below 20-30 cm depth significantly reduced the survival of C. gloeosporioides f. sp. manihotis on infected materials. Burial at 30 cm depth for 150 days completely eradicated the fungus on the infected cuttings. These studies have shown that C. gloeosporioides f. sp. manihotis could survive on infected cuttings for more than 8 months, but less likely to survive in soil for up to 4 months. The potential of high cassava anthracnose disease transmission in cassava planting materials during storage is also reported

Efficacy of antimicrobial plant crude extracts on the growth in Colletotrichum gloeosporiodes f. sp. manihotis

This study was conducted to investigate a cheap and readily available alternative control measure for cassava anthracnose disease causal agent (Colletotrichum gloeosporioides f. sp. manihotis), through the use of antimicrobial crude plant extracts such as neem (Azadirachta indica), bitter leaf (Vernonia amygdalina), Ocimum gratissimum and Xylopia aethiopica, on the fungal growth parameters (mycelial growth, sporulation and germ tube development). The extracts at concentration levels of 25, 50, 75 and 100% full strength concentration showed an inhibitory effect on mycelial growth, germ tube development and sporulation of fungal isolates 05FCN, 10FCN, 12FCN and 26FCN. Neem seed and leaf extracts at 100% showed a total reduction in sporulation in most of the fungal isolates. The inhibitory properties of the plant crude extracts indicated a promising control option for consideration in cassava treatments of planting stocks, particularly in areas where farming is at a basic subsistent level, and less available money to meet the high cost of pesticides

Effect of planting season on cassava anthracnose disease development

Twelve cassava (Manihot esculenta Crantz) genotypes were planted under natural field conditions for two different cropping seasons (wet and dry), in 1992 and 1993 at the research farm of the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria. The trial studied the effect of planting season on cassava anthracnose disease (CAD) symptoms expression (disease severity index, canker size and first canker distance from the ground). Another trial was carried out to investigate genotype susceptibility over three consecutive planting seasons using CAD incidence and severity. Disease severity index (DSI) differed significantly (p⩽0.05) among cassava genotypes in both wet and dry season planting. CAD incidence and severity also differed significantly (p⩽0.05) among genotypes, with the wet season recording higher disease incidence and canker size. CAD incidence and severity showed significant correlation in the dry season (r=0.91), but were negatively correlated (r=−0.87) in the wet season. Necrotic lesion size and disease severity in the dry season were not significantly correlated (r=0.23). Differences in genotypic reaction to CAD incidence and severity were found in 1992, 1993 and 1994 plantings. Genotypes 30211 and 91/00684 showed more stable resistance over the three years of planting when compared with genotypes 90/00333, 91/00396 and 89/00011 which showed fluctuations in CAD disease symptom expression. Yield assessment of cassava genotypes during the cropping seasons, over the 2-year period, showed great variation in plant stand, tuber number and weight and percent dry matter content

Field reaction of cassava genotypes to anthranose, bacterial blight, cassava mosaic disease and their effects on yield

Thirteen cassava genotypes were evaluated at the International Institute of Tropical Agriculture, Ibadan, Nigeria for anthracnose (CAD), bacterial blight (CBB) and cassava mosaic disease (CMD) incidence and severity, and their effects on yield, for three consecutive planting seasons. There were significant differences (P<0.05) in CAD, CBB and CMD incidence and severity amongst the cassava genotypes across the planting seasons. Yield assessment showed significant differences (P<0.05) in storage root number, plant stand, root fresh weight and dry matter content among the cassava genotypes. There was no significant variation in tuber rot among the genotypes, and 80% of the genotypes did not show any tuber root rot when harvested 12 months after planting. CBB and CAD incidences were significantly and positively correlated (r=0.43), whereas CBB and CMD incidences were not significantly correlated (r=0.03). CAD and CMD incidence and severity were highly correlated (r=0.82 and r=0.76, respectively). CBB incidence was negatively correlated with storage root weight and fresh root tuber number (r=-0.45 and r=-0.48, respectively). CMD severity showed a significant negative correlation with storage root weight (r=0.44). Cassava genotypes TMS 30001, 30211 and 88/01087 showed a stable resistance over 3 planting seasons to CAD, CBB and CMD

Mycelial growth, sporulation and spore germination of virulent Colletotrichum gloeosporiodes f. sp. manihotis isolates under selected growth conditions

Thirty isolates of Colletotrichum gloeosporioides f. sp. manihotis causal organism of cassava anthracnose disease (CAD), were collected from cankers on cassava stems in cassava-growing zones of Nigeria. Using a pathogenicity test, five virulent isolates (05FCN, 10FCN, 12FCN, 18FCN and 26FCN) were identified and subsequently used in determining the effect of temperature, pH, light and growth medium on mycelial growth, sporulation and spore germination