201 research outputs found
Optical spectroscopy of the low-mass X-ray binary GX 9+9
No full textPhase-resolved medium-resolution VLT spectroscopy of the low-mass X-ray binary GX 9+9 has revealed narrow C ill emission lines that move in phase relative to our new estimate of the ephemeris, and show a velocity amplitude of 230 +/not superset of 35 km s(-1). We identify the origin of these lines as coming from the surface of the donor star, thereby providing the first estimate of the mass function of f(M-1) >= 0.22 M-circle dot. Rotational broadening estimates together with assumptions for the mass donor give 0.07 <= q <= 0.35 and 182 <= K-2 <= 406 km s(-1). Despite a low-mass ratio, there is no evidence for a superhump in our data set. Doppler maps of GX 9+9 show the presence of a stream overflow, either in the form of material flowing downward along the accretion disc rim or in a similar fashion as occurs in high mass transfer rate cataclysmic variables known as the SW Sex stars. Finally, we note that the Bowen region in GX 9+9 is dominated by C in instead of N III emission as has been the case for most other X-ray binaries
Attentional focus, dispositional reinvestment, and skilled motor performance under pressure
No full textCopyright @ 2006 Human KineticsAttentional processes governing skilled motor behavior were examined in two studies. In Experiment 1, field hockey players performed a dribbling task under single-task, dual-task, and skill-focused conditions under both low and high pressure situations. In Experiment 2, skilled soccer players performed a dribbling task under single-task, skill-focused, and process-goal conditions, again under low and high pressure situations. Results replicated recent findings regarding the detrimental effect of skill-focused attention and the facilitative effect of dual-task conditions on skilled performance. In addition, focusing on movement related process goals was found to adversely affect performance. Support for the predictive validity of the Reinvestment Scale was also found, with high reinvesters displaying greater susceptibility to skill failure under pressure. Results were consistent with explicit monitoring theories of choking and are further discussed in light of the conceptual distinction between explicit monitoring and reinvestment of conscious control
Targeted genetic testing for familial hypercholesterolaemia using next generation sequencing:a population-based study
No full textBACKGROUND: Familial hypercholesterolaemia (FH) is a common Mendelian condition which, untreated, results in premature coronary heart disease. An estimated 88% of FH cases are undiagnosed in the UK. We previously validated a method for FH mutation detection in a lipid clinic population using next generation sequencing (NGS), but this did not address the challenge of identifying index cases in primary care where most undiagnosed patients receive healthcare. Here, we evaluate the targeted use of NGS as a potential route to diagnosis of FH in a primary care population subset selected for hypercholesterolaemia.METHODS: We used microfluidics-based PCR amplification coupled with NGS and multiplex ligation-dependent probe amplification (MLPA) to detect mutations in LDLR, APOB and PCSK9 in three phenotypic groups within the Generation Scotland: Scottish Family Health Study including 193 individuals with high total cholesterol, 232 with moderately high total cholesterol despite cholesterol-lowering therapy, and 192 normocholesterolaemic controls.RESULTS: Pathogenic mutations were found in 2.1% of hypercholesterolaemic individuals, in 2.2% of subjects on cholesterol-lowering therapy and in 42% of their available first-degree relatives. In addition, variants of uncertain clinical significance (VUCS) were detected in 1.4% of the hypercholesterolaemic and cholesterol-lowering therapy groups. No pathogenic variants or VUCS were detected in controls.CONCLUSIONS: We demonstrated that population-based genetic testing using these protocols is able to deliver definitive molecular diagnoses of FH in individuals with high cholesterol or on cholesterol-lowering therapy. The lower cost and labour associated with NGS-based testing may increase the attractiveness of a population-based approach to FH detection compared to genetic testing with conventional sequencing. This could provide one route to increasing the present low percentage of FH cases with a genetic diagnosis.</p
A Versus K Revisited: Evidence from Selected MENA Countries
No full textThis paper reconsiders the A versus K debate, namely, which factor is the leading contributor to economic growth? productivity gains (A) or factor accumulation (K). The growth accounting analysis is conducted for ten Middle Eastern and North African (MENA) countries over the period 1960-1998. The long-run share of capital in national income is estimated using cointegration (country-specific) and panel data (region-specific) methods. We find that for most of the countries in our sample the share of capital is much higher than the conventional share of 0.3-0.4. The growth accounting exercise conducted with the incorporation of human capital reveals that for the MENA region the contribution of productivity gains to economic growth is negligible and frequently even detrimental. Thus, we conclude that it is factor (both physical and human) accumulation that drives the economic performance of MENA economies.Growth Accounting, Productivity and Factor Accumulation, MENA, Middle-East, Cointegration, Panel Data
Seed production of barnyardgrass (Echinochloa crus-galli) in response to time of emergence in cotton and rice
No full textThe spread of herbicide resistance in barnyardgrass (Echinochloa crus-galli (L.) Beauv.) poses a serious threat to crop production in the southern United States. A thorough knowledge of the biology of barnyardgrass is fundamental for designing effective resistance-management programmes. In the present study, seed production of barnyardgrass in response to time of emergence was investigated in cotton and rice, respectively, in Fayetteville and Rohwer, Arkansas, over a 2-year period (2008–09). Barnyardgrass seed production was greater when seedlings emerged with the crop, but some seed production was observed even if seedlings emerged several weeks after crop emergence. Moreover, barnyardgrass seed production was highly variable across environments. When emerging with the crop (0 weeks after crop emergence (WAE)), barnyardgrass produced c. 35 500 and 16 500 seeds/plant in cotton, and c. 39 000 and 2900 seeds/plant in rice, in 2008 and 2009, respectively. Seed production was observed when seedlings emerged up to 5 WAE (2008) or 7 WAE (2009) in cotton and up to 5 WAE (2008, 2009) in rice; corresponding seed production was c. 2500 and 1500 seeds/plant in cotton, and c. 14 700 and 110 seeds/plant in rice, in 2008 and 2009, respectively. The results suggest that cultural approaches that delay the emergence of barnyardgrass or approaches that make the associated crop more competitive will be useful in integrated management programmes. In the context of herbicide resistance management, it may be valuable to prevent seed return to the seedbank, irrespective of cohorts. The findings are vital for parameterizing herbicide resistance simulation models for barnyardgrass
Timing and Application Rate for Sequential Applications of Glufosinate are Critical for Maximizing Control of Annual Weeds in LibertyLink® Soybean
No full textPreserving the utility of glufosinate in both LibertyLink soybean and other glufosinate-resistant crops is critical for managing herbicide-resistant weeds. An experiment with a two-factor factorial arrangement was conducted at the Arkansas Agricultural Research and Extension Center in Fayetteville, AR, in 2015, 2016, and 2017 to evaluate the efficacy of glufosinate in single and sequential applications at various rates on 8–32 cm tall Palmer amaranth, barnyardgrass, and broadleaf signalgrass. Herbicide treatments consisted of glufosinate applied at 454, 595, 738, and 882 g ai ha−1 (Factor 1) with either no sequential application or a sequential application occurring 7, 10, 14, or 21 days after the initial application (DAI) (Factor 2). For treatments that contained a sequential application, the same rate used in the initial application (e.g., 451 g ai ha−1) was also used in the sequential. Regardless of species and rate, sequential applications were always superior to single applications. Palmer amaranth control 3 weeks after the final treatment (WAF) was 8% greater when the sequential application occurred 10 DAI compared to 21 DAI, averaged over glufosinate rates. When at least 595 g ai ha−1 glufosinate was used in a treatment, no differences between the 7-, 10-, 14-, and 21-day sequential application intervals were observed for barnyardgrass or broadleaf signalgrass control, 3 WAF. Soybean yields were greater when the glufosinate applications occurred 7 or 10 d apart compared to 21 d, averaged over glufosinate rates. When large weeds are present in the field, these data suggest that glufosinate should be applied sequentially with a 7- to 14-day interval between applications. If sequential applications of glufosinate are used in combination with a comprehensive weed control management program, the value of the LibertyLink technology should be preserved by mitigating the risk of glufosinate resistance
Changes in Senna obstuifolia Germination Requirements over 12 Months under Field Conditions
No full textSenna
obtusifolia seeds were collected in
Fall 2003 and immediately field sown to assess
dormancy alleviation and effect of
after-ripening over a 12-month period on light
and temperature requirements for germination.
Seeds did not exhibit physical dormancy at
maturation and readily germinated over a broad
range of light and thermal conditions. Dormancy
gradually increased during Winter months,
resulting in only a small fraction of the
population capable of germination by early
Spring. Dormancy break did not occur at a
specific time of the year nor did dormancy
alleviation increase over the 12-month period
following maturation. Conditions during Spring
and Summer coincided with thermal requirements
for germination of the nondormant fraction of
the population. Senna
obtusifolia seeds were nonresponsive to
red and far-red lights, and seeds did not acquire
a light requirement following burial for 6
months
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