The efficacy of neem seed extract (Azadirachta indica) to control tick infestation in Tswana, Simmentaler and Brahman cattle

The aim of this experiment was to evaluate the use of neem seed extract for controlling common cattle ticks of the Ixodidae species. Three bulls and three cows of the Tswana, Brahman and Simmentaler breeds were cleared of ticks using ether and hand-picking techniques. Each animal was then naturally infested with ticks. A 5% (w/v) water extract of neem seed kernel was applied at a rate of 5 g/kg body weight to various anatomical sites on the animals allocated to the experimental treatment, while the control treatment animals were sprayed with tap water. Treated and control animals grazed together and were mustered at weekly intervals for examination. Tick population densities on animals treated with neem seed extract were lower than on untreated animals. Indigenous Tswana cattle harboured fewer ticks during periods of tick abundance than Brahman or Simmentaler cattle. It was concluded that neem seed extract is effective in controlling ectoparasites on livestock. South African Journal of Animal Science Vol.32(1) 2002: 1-

Irregular Satellites of the Planets: Products of Capture in the Early Solar System

All four giant planets in the Solar system possess irregular satellites, characterized by large, highly eccentric and/or inclined orbits that are distinct from the nearly circular, uninclined orbits of the regular satellites. This difference can be traced directly to different modes of formation. Whereas the regular satellites grew by accretion within circumplanetary disks the irregular satellites were captured from initially heliocentric orbits at an early epoch. Recently, powerful survey observations have greatly increased the number of known irregular satellites, permitting a fresh look at the group properties of these objects and motivating a re-examination of the mechanisms of capture. None of the suggested mechanisms, including gas-drag, pull-down, and three-body capture, convincingly fit the group characteristics of the irregular satellites. The sources of the satellites also remain unidentified.Comment: 51 pages, 17 figures, 5 tables, to appear in ARAA 200

Sliding Crack Model for Nonlinearity and Hysteresis in the Triaxial Stress‐Strain Curve of Rock, and Application to Antigorite Deformation

Under triaxial deviatoric loading at stresses below failure, rocks generally exhibit nonlinearity and hysteresis in the stress‐strain curve. In 1965, Walsh first explained this behavior in terms of frictional sliding along the faces of closed microcracks. The hypothesis is that crack sliding is the dominant mode of rock inelasticity at moderate compressive stresses for certain rock types. Here we extend the model of David et al. (2012, https://doi.org/10.1016/j.ijrmms.2012.02.001) to include (i) the effect of the confining stress; (ii) multiple load‐unload cycles; (iii) calculation of the dissipated strain energy upon unload‐reload; (iv) either frictional or cohesive behavior; and (v) either aligned or randomly oriented cracks. Closed‐form expressions are obtained for the effective Young's modulus during loading, unloading, and reloading, as functions of the mineral's Young's modulus, the crack density, the crack friction coefficient and cohesion for the frictional and cohesive sliding models, respectively, and the crack orientation in the case of aligned cracks. The dissipated energy per cycle is quadratic and linear in stress for the frictional and cohesive models, respectively. Both models provide a good fit to a cyclic loading data set on polycrystalline antigorite, based on a compilation of literature and newly acquired data, at various pressures and temperatures. At high pressure, with increasing temperature, the model results reveal a decrease in friction coefficient and a transition from a frictionally to a cohesively controlled behavior. New measurements of fracture toughness and tensile strength provide quantitative support that inelastic behavior in antigorite is predominantly caused by shear crack sliding and propagation without dilatancy

An artificial neural network-based rainfall runoff model for improved drainage network modelling

This Presentation is brought to you for free and open access by the City College of New York at CUNY Academic Works. It has been accepted for inclusion in International Conference on Hydroinformatics by an authorized administrator of CUNY Academic Works. For more information, please contact [email protected] th International Conference on Hydroinformatics HIC 2014, New York City, USAModelling rainfall-runoff processes enables hydrologists to plan their response to flooding events. Urban drainage catchment modelling requires rainfall-runoff models as a prerequisite. In the UK, one of the main software tools used for drainage modelling is InfoWorks CS, based on relatively simple methods which are relatively robust in predicting runoff. This paper presents an alternative approach to modelling runoff that will allow for the complex inter-relation of runoff that occurs from impermeable areas, permeable areas, local surface storage and variation in rainfall induced infiltration. Apart from the uncertainties associated with the measurement of connected surfaces to the drainage system, the physical processes involved in runoff are nonlinear, making artificial neural networks (ANNs) an ideal candidate for modelling them. ANNs have been used for runoff prediction in natural catchments, and recently on a study for predicting the performance of urban drainage systems. This study seeks to determine an input set that predicts sewerage flow in urban catchments where the runoff is dominated by infiltration, a major issue for the water industry. A framework is proposed in which an ANN is trained by an evolutionary algorithm, which optimises ANN weights; results are assessed using the Nash-Sutcliffe Efficiency Coefficient. The model is demonstrated on a real-world case study site for which rainfall, flow, air temperature and groundwater levels in three boreholes have been measured. Various combinations of these data are used as model inputs, examining a mixture of daily and sub-daily timesteps. The best predictions are generated from daily linearly combined antecedent rainfall and air temperature, although sub-daily information improves the worst-case performance of the model. Although infiltration is affected by groundwater levels, incorporating groundwater into the model does not improve predictions. The proposed ANN model is capable of producing acceptable predictions, thus avoiding many of the uncertainties involved in traditional infiltration modelling

Is youth unemployment really the major worry? (AOM)

Youth unemployment is neither the only nor the basic problem of the European labour market. The comparative analysis of unemployment data demonstrates that the unemployment of older people is even more serious. The article proves that the weight of young people in total unemployment has as a tendency been declining in the “inner periphery” of the EU, among them in Central and Eastern European member states (CEECs). The trend is just the opposite in the developed or “core” countries of the Union where youngsters took a higher share in total unemployment in 2012 than 10-12 years ago. In Europe there are millions of young people beyond the active unemployed who do not want to work or think they cannot find a job that fulfils their expectations and refuse to take part in any kind of education or training (NEETs-“Not in Employment, Education or Training”). By estimating the rate of NEETs in the adult population the article claims that the NEETs-phenomenon is not the differentia specifica of the youth. At the end the article details two suggestions for the mitigation of the problem. It concludes that the joblessness in Europe is an old and tendencially worsening problem that cannot be solved by particular policies

Influence of fluids on VP/VS ratio: increase or decrease?

The evolution of the ratio between P- and S-wave velocities (VP/VS) with increasing fluid-saturated porosity is computed for isotropic rocks containing spheroidal pores. The ratio VP/VS is shown to either decrease or increase with increasing porosity, depending on the aspect ratio α of the pores, fluid to solid bulk modulus ratio ζ and Poisson’s ratio ν0 of the solid constituents of the rock. A critical initial Poisson’s ratio ν0, crit is computed, separating cases where VP/VS increases (if ν0 ν0, crit) with increasing porosity. For thin cracks and highly compressible fluids, ν0, crit is approximated by 0.157ζ/α⁠, whereas for spherical pores ν0, crit is given by 0.2 + 0.8ζ. When ν0 is close to ν0, crit, the evolution of VP/VS with increasing fluid-saturated porosity is near neutral and depends on subtle changes in pore shape and fluid properties. This regime is found to be relevant to partially dehydrated serpentinites in subduction zones (porosity of aspect ratio near 0.1 and ζ in the range 0.01–0.1), and makes detection of these rocks and possibly elevated fluid pressures difficult from VP/VS only

Long term adverse drug reaction to Efavirenz in a HIV infected adolescent

Efavirenz is one of the medications used in combined antiretroviral therapy (ART) for the management of HIV infection in adolescents. Various central nervous system adverse reactions have been reported in patients commencing antiretroviral therapy with a regimen containing Efavirenz. These reactions tend to be acute, commonly occurring in the first six months of therapy. Adverse reactions following long term use of Efavirenz for ART is rare among adults and rarer still among children and adolescents. There is only one published case of serious adverse reaction to Efavirenz in an adolescent after long-term use. The case of a male HIV Positive Nigerian patient aged 13 years. He presented with five-day history of Difficulty sleeping, abnormal dreams, inability to concentrate, restlessness, irrational behavior and long-term memory loss. There was no previous history of psychiatric illness and no suggestive social or family history. Patient was on Efavirenz containing regimen about 6.5 years till presentation with adverse reaction mainly affecting behavior, thought processes and memory. After discontinuing Efavirenz and replacing with Nevirapine in his combined ART regimen, all neuropsychiatric manifestations ceased .He regained his memory, no longer had bad dreams or demonstrated any irrational behavior or attitude. Physicians who are involved in the care of HIV infected patients need to be aware of the possibility of adverse Drug reactions occurring in patients who have been on antiretroviral drugs for years. This possibility should not be excluded from possible differential diagnosis.KEY WORDS: Adolescent; Efavirenz; HIV Infection; Reactions; Adverse drug; Psychomotor Agitation; Long ter

Genetics University of Toronto Thrombophilia Study in Women (GUTTSI): genetic and other risk factors for venous thromboembolism in women

BACKGROUND: Women may be at increased risk for venous thromboembolism (VTE) as compared with men. We studied the effects of genetic and biochemical markers of thrombophilia in women, in conjunction with other established risk factors for VTE. METHOD: The present retrospective case-control study was conducted in a thrombosis treatment programme at a large Toronto hospital. The cases were 129 women aged 16-79 years with objectively confirmed VTE. Age-matched control individuals were women who were free of venous thrombosis. Neither cases nor control individuals had known cardiovascular disease. Participants were interviewed regarding personal risk factors for VTE, including smoking, history of malignancy, pregnancy, and oestrogen or oral contraceptive use. Blood specimens were analyzed for common single nucleotide polymorphisms of prothrombin, factor V and methylenetetrahydrofolate reductase (MTHFR; C677T, A1298C and T1317C), and the A66G polymorphism for methionine synthase reductase (MTRR).Fasting plasma homocysteine was also analyzed. RESULTS: Women with VTE were significantly more likely than female control individuals to carry the prothrombin polymorphism and the factor V polymorphism, or to have fasting hyperhomocysteinaemia. Homozygosity for the C677T MTHFR gene was not a significant risk factor for VTE, or were the A1298C or T1317C MTHFR homozygous variants. Also, the A66G MTRR homozygous state did not confer an increased risk for VTE. CONCLUSION: Prothrombin and factor V polymorphisms increased the risk for VTE in women, independent from other established risk factors. Although hyperhomocysteinaemia also heightens this risk, common polymorphisms in two genes that are responsible for homocysteine remethylation do not. These findings are consistent with previous studies that included both men and women

Rupture Energetics in Crustal Rock From Laboratory‐Scale Seismic Tomography

The energy released during earthquake rupture is partly radiated as seismic waves and mostly dissipated by frictional heating on the fault interface and by off‐fault fracturing of surrounding host rock. Quantification of these individual components is crucial to understand the physics of rupture. We use a quasi‐static rock fracture experiment combined with a novel seismic tomography method to quantify the contribution of off‐fault fracturing to the energy budget of a rupture and find that this contribution is around 3% of the total energy budget and 10% of the fracture energy Gc. The off‐fault dissipated energy changes the physical properties of the rock at the early stages of rupture, illustrated by the 50% drop in elastic moduli of the rock near the fault, and thus is expected to greatly influence later stages of rupture and slip. These constraints are a unique benchmark for calibration of dynamic rupture models

Low-Frequency Measurements of Seismic Moduli and Attenuation in Antigorite Serpentinite

Laboratory measurements of seismic moduli and attenuation in antigorite serpentinite at a confining pressure of 200 MPa and temperatures up to 550 °C provide new results relevant to the interpretation of geophysical data in subduction zones. A polycrystalline antigorite specimen was tested via forced oscillations at small strain amplitudes and seismic frequencies (millihertz to hertz). The shear modulus has a temperature sensitivity, ∂G/∂T, averaging −0.017 GPa/K. Increasing temperature above 500 °C results in more intensive shear attenuation ( equation/grl58579-math-0001.png) and associated modulus dispersion, with equation/grl58579-math-0002.png increasing monotonically with increasing oscillation period and temperature. This “background” relaxation is adequately captured by a Burgers model for viscoelasticity and possibly results from intergranular mechanisms. Attenuation is higher in antigorite ( equation/grl58579-math-0003.png at 550 °C and 0.01 Hz) than in olivine ( equation/grl58579-math-0004.png below 800 °C), but such contrast does not appear to be strong enough to allow robust identification of antigorite from seismic models of attenuation only