Speculation and Volatility Spillover in the Crude Oil and Agricultural Commodity Markets: A Bayesian Analysis

This paper assesses the roles of various factors influencing the volatility of crude oil prices and the possible linkage between this volatility and agricultural commodity markets. Stochastic volatility models are applied to weekly crude oil, corn and wheat futures prices from November 1998 to January 2009. Model parameters are estimated using Bayesian Markov chain Monte Carlo methods. The main results are as follows. Speculation, scalping, and petroleum inventories are found to be important in explaining oil price variation. Several properties of crude oil price dynamics are established including mean-reversion, a negative correlation between price and volatility, volatility clustering, and infrequent compound Poisson jumps. We find evidence of volatility spillover among crude oil, corn and wheat markets after the fall of 2006. This could be largely explained by tightened interdependence between these markets induced by ethanol production.Gibbs sampling, Merton jump, leverage effect, stochastic volatility, Demand and Price Analysis, Financial Economics, Resource /Energy Economics and Policy, G13, Q4,

Prevalence and resistance gene mutations of multi-drug resistant and extensively drug resistant mycobacterium tuberculosis in the Eastern Cape

The emergence and spread of multi-drug resistant (MDR-TB) and extensively drugresistant tuberculosis (XDR-TB) are a major medical and public problem threatening the global health. The objectives of this study were to (i) determine the prevalence of MDR-TB and XDR-TB in the Eastern Cape; (ii) analyze patterns of gene mutations in MDR-TB and (iii) identify gene mutations associated with resistance to second line injectable drugs in XDR-TB isolates. A total of 1520 routine sputum specimens sequentially received within a period of 12 months i.e. February 2012 to February 2013 from all MDR-TB and XDR-TB patients treated by Hospitals and clinics in the Eastern Cape were included in this study, of which 1004 had interpretable results. Samples were analyzed with the Genotype MTBDRplus VER 2.0 assay kit (Hain Lifescience) for detection of resistance to Rifampicin and Isoniazid while solid and liquid culture drug susceptibility tests were used for ethambutol, streptomycin, ethionamide, ofloxacin, capreomycin and amikacin. PCR and sequence analysis of short regions of target genes gyrA, (encode subunit of DNA topoisomerase gyrase), rrs (16S rRNA) and tlyA (encodes a 2’-O-methyltransferase) were performed on 20 XDR-TB isolates. MTBDRplus kit results and drug susceptibility tests identified 462 MDR-TB, 284 pre-XDR and 258 XDR-TB isolates from 267 clinics and 25 hospitals in the Eastern Cape. There was a high frequency of resistance to streptomycin, ethionamide, amikacin, ofloxacin and capreomycin. Mutation patterns indicated differences between the health districts as well as differences between the facilities within the health districts. The most common mutation patterns observed were: (i) ΔWT3, ΔWT4, MUT1 [D516V+del515] (rpoB), ΔWT, MUT1 [S315T1] (katG), ΔWT1 [C15T] (inhA) [39 MDR, 204 XDR-TB and 214 pre XDR-TB isolates], (ii) ΔWT8, MUT3 [L533P+S531L] (rpoB), ΔWT, MUT1 [S315T1] [145 MDR, 18 pre-XDR and 3 XDR-TB solates] and (iii) ΔWT3, WT4 [D516Y+del515] (rpoB), ΔWT, MUT1 [S315T1] (katG) [75 MDR, 1 pre-XDR and 7 XDR-TB isolates]. Mutations in inhA promoter regions were strongly associated with XDR-TB isolates. Two thirds (66.6 percent (669/1004) of the isolates had inhA mutations present with 25.4 percent (170/669) found among the MDR isolates, 39.2 percent (262/669) among the pre-XDR isolates and 35.4 percent (237/669) among the XDR-TB isolates, which implies that these resistant isolates are being spread by transmission within the community and circulating in the province. There was good correlation between XDR-TB drug susceptibility test results and sequence analyses of the gyrA and rrs genes. The majority of XDR-TB isolates contained mutations at positions C269T (6/20) and 1401G (18/20) in gyrA and rrs genes respectively. Sequence analysis of short regions of gyrA and rrs genes may be useful for detection of fluoroquinolone and amikacin/ kanamycin resistance in XDR-TB isolates but the tlyA gene is not a sensitive genetic marker for capreomycin resistance. This study highlighted the urgent need for the development of rapid diagnostics for XDR-TB and raised serious concerns regarding ineffective patientmanagement resulting in ongoing transmission of extremely resistant strains of XDRTB in the Eastern Cape suggesting that the Eastern Cape could be fast becoming the epicenter for the development of Totally Drug-resistant Tuberculosis (TDR-TB) in South Africa

Reclaiming the Spiritual Leadership Role of Christian Parents in Family Life: Coaching and Markers

Christians in the Western culture often struggle to pass on their faith to the next generation and as a result, the way God designed the family to function is being unwittingly abandoned. Countless parents today are leaving genuine faith and reliance on God behind. Though God\u27s Word gives specific instructions on how to maintain and pass on faith, many have abdicated this injunction. In an effort to encourage authentic faith within the family, the local church can come alongside parents to help them understand and share their faith by offering training and coaching to embrace their own faith and pass it on to their children. This project is designed as a model to teach and celebrate spiritual mile markers, coupled with coaching for parents so they may reclaim their place as spiritual leaders within their families and guide their children in the legacy of Christian faith

Characterization of germanium/silicon p-n junction fabricated by low temperature direct wafer bonding and layer exfoliation

The current transport across a p-Ge/n-Si diode structure obtained by direct wafer bonding and layer exfoliation is analysed. A low temperature anneal at 400 degrees C for 30 min was used to improve the forward characteristics of the diode with the on/off ratio at -1 V being > 8000. Post anneal, the transport mechanism has a strong tunnelling component. This fabrication technique using a low thermal budget (T <= 400 degrees C) is an attractive option for heterogeneous integration. (C) 2012 American Institute of Physics. (doi:10.1063/1.3688174

Retrospective Assessment of Childhood Sexual and Physical Abuse: A Comparison of Scaled and Behaviorally Specific Approaches

This study compared retrospective reports of childhood sexual and physical abuse as assessed by two measures: the Childhood Trauma Questionnaire (CTQ), which uses a Likert-type scaling approach, and the Computer Assisted Maltreatment Inventory (CAMI), which employs a behaviorally specific means of assessment. Participants included 1,195 undergraduate students recruited from three geographically diverse universities. Agreement was high across the two measures in the classification of victim status (92% and 80% for sexual and physical abuse, respectively). However, the CTQ classified more participants as sexually abused than did the CAMI, whereas the opposite trend was found for physical abuse. For child physical abuse, many participants reporting abusive acts on the CAMI scored below the cut-point for physical abuse on the CTQ. Classifi cation differences for both types of abuse were largely unrelated to demographic factors, socially desirable responding, or self-reported withholding of information. The implications of these results are discussed in light of future research using retrospective methods of assessing childhood abuse

Differences in Brain Structure and Function Among Yoga Practitioners and Controls

Background: Yoga is a mind-body based physical activity that has demonstrated a variety of physiological, psychological and cognitive health benefits. Although yoga practice has shown to improve cognitive performance, few studies have examined the underlying neurological correlates.Objective: The current study aimed to determine the differences in gray matter volume of the hippocampus, thalamus and caudate nucleus and brain activation during the Sternberg working memory task.Method: Participants were 13 experienced yoga practitioners (mean age = 35.8), defined as having more than 3 years of regular yoga practice, and 13 age- and sex-matched controls (mean age = 35.7). All participants completed a 6-min walk test to assess fitness, psychosocial and demographic questionnaires; and underwent magnetic resonance imaging to assess gray matter volume and brain activation.Results: There were no group differences on demographic measures of income, education and on estimated VO2max or physical activity levels. Gray matter volume differences were observed in the left hippocampus, showing greater volume in experienced yoga practitioners compared to controls (p = 0.017). The functional MRI results revealed less activation in the dorsolateral prefrontal cortex in yoga practitioners compared to controls during the encoding phase of the Sternberg task (p &lt; 0.05). Reaction time and accuracy on the task did not differ between the groups.Conclusions: Our results suggest an association between regular long-term yoga practice and differential structure and function of specific brain regions involved in executive function, specifically working memory, which has previously shown to improve with yoga practice. Future studies need to examine intervention effects of yoga and explore its potential to maintain and improve cognitive health across the lifespan through longitudinal and intervention studies

Estimating the effect of a rifampicin resistant tuberculosis diagnosis by the Xpert MTB/RIF assay on two-year mortality

Studies assessing patient-centred outcomes of novel rifampicin resistant tuberculosis (RR-TB) diagnostics are rare and mostly apply conventional methods which may not adequately address biases. Even though the Xpert MTB/RIF molecular assay was endorsed a decade ago for simultaneous diagnosis of tuberculosis and RR-TB, the impact of the assay on mortality among people with RR-TB has not yet been assessed. We analysed data of an observational prospective cohort study (EXIT-RIF) performed in South Africa. We applied a causal inference approach using inverse odds of sampling weights to rectify survivor bias and selection bias caused by differing screening guidelines. We also adjusted for confounding using a marginal structural model with inverse probability of treatment weights. We estimated the total effect of an RR-TB diagnosis made by the Xpert assay versus the pre-Xpert diagnostic algorithm (entailing a targeted Line Probe Assay (LPA) among TB-confirmed patients) on two-year mortality and we assessed mediation by RR-treatment initiation. Of the 749 patients diagnosed with RR-TB [247 (33%) by the pre-Xpert diagnostic algorithm and 502 (67%) by the Xpert assay], 42.7% died. Of these, 364 (48.6%) patients died in the pre-Xpert group and 200 (39.8%) in the Xpert group. People diagnosed with RR-TB by the Xpert assay had a higher odds of RR-TB treatment initiation compared to those diagnosed by the targeted LPA-based diagnostic process (OR 2.79; 95%CI 2.19–3.56). Receiving an RR-TB diagnosis by Xpert resulted in a 28% reduction in the odds of mortality within 2 years after presentation to the clinic (ORCI 0.72; 95%CI 0.53–0.99). Causal mediation analysis suggests that the higher rate of RR-TB treatment initiation in people diagnosed by the Xpert assay explains the effect of Xpert on 2-year mortality [natural indirect effect odds ratio 0.90 (95%CI 0.85–0.96). By using causal inference methods in combination with high quality observational data, we could demonstrate that the introduction of the Xpert assay caused a 28% reduction in 2-year odds of mortality of RR-TB. This finding highlights the need for advocacy for a worldwide roll-out of rapid molecular tests. Because the effect is mainly caused by increased RR-TB treatment initiation, health care systems should also ensure timely initiation of effective treatment upon an RR-TB diagnosis

Negative impacts of invasive predators used as biological control agents against the pest snail Lissachatina fulica: the snail Euglandina ‘rosea’ and the flatworm Platydemus manokwari

Since 1955 snails of the Euglandina rosea species complex and Platydemus manokwari flatworms were widely introduced in attempted biological control of giant African snails (Lissachatina fulica) but have been implicated in the mass extinction of Pacific island snails. We review the histories of the 60 introductions and their impacts on L. fulica and native snails. Since 1993 there have been unofficial releases of Euglandina within island groups. Only three official P. manokwari releases took place, but new populations are being recorded at an increasing rate, probably because of accidental introduction. Claims that these predators controlled L. fulica cannot be substantiated; in some cases pest snail declines coincided with predator arrival but concomitant declines occurred elsewhere in the absence of the predator and the declines in some cases were only temporary. In the Hawaiian Islands, although there had been some earlier declines of native snails, the Euglandina impacts on native snails are clear with rapid decline of many endemic Hawaiian Achatinellinae following predator arrival. In the Society Islands, Partulidae tree snail populations remained stable until Euglandina introduction, when declines were extremely rapid with an exact correspondence between predator arrival and tree snail decline. Platydemus manokwari invasion coincides with native snail declines on some islands, notably the Ogasawara Islands of Japan, and its invasion of Florida has led to mass mortality of Liguus spp. tree snails. We conclude that Euglandina and P. manokwari are not effective biocontrol agents, but do have major negative effects on native snail faunas. These predatory snails and flatworms are generalist predators and as such are not suitable for biological control