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Search Results: 1 - 10 of 12435 matches for " Christopher Ference "
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Use of carnauba based carrier for copper sprays reduces infection by Xanthomonas citri subsp. citri and Diaporthe citri in Florida commercial grapefruit groves  [PDF]
Jan Narciso, Wilbur Widmer, Christopher Ference, Mark Ritenour, Ricardo Diaz
Agricultural Sciences (AS) , 2012, DOI: 10.4236/as.2012.37117
Abstract: Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), is a bacterial disease of citrus and results in peel blemishes rendering fresh fruit unsalable. Xcc is most active in warm, wet Florida summers where tissues are infected during periods of active growth. Melanose, caused by Diaporthe citri, is common in citrus producing countries, but, like canker, is only important for fresh market fruit. To control canker and melanose, Florida growers spray trees with copper formulations (Cu), but these sprays are removed by strong rains and intense radiation of Florida summers. A study was undertaken in FL commercial grapefruit groves in 2009 and 2010 to assess the efficiency of a spray combining copper with a specially formulated, hydrating wax (WashGard?) (WG). Using a 21-day spray schedule for the season, fruit were sprayed with WG + Cu, Cu and Control (no spray). Fruit from trees sprayed with WG + Cu had approximately 10 and17% more canker free fruit in 2009 and 2010 respectively compared to trees sprayed with copper alone. Compared to control trees the canker free fruit incidence was increased by ≈10% in 2009 and 57% in 2010. For melanose there was 40% more disease free fruit (treated) over fruit from trees with no treatment in 2009 and approximately 20% more in 2010. Controlling infection with this spray significantly reduces citrus canker and melanose, increasing the percentage of marketable fruit.
A Common KIF6 Polymorphism Increases Vulnerability to Low-Density Lipoprotein Cholesterol: Two Meta-Analyses and a Meta-Regression Analysis
Brian A. Ference, Wonsuk Yoo, John M. Flack, Michael Clarke
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0028834
Abstract: Background We sought to determine if a common polymorphism can influence vulnerability to LDL cholesterol, and thereby influence the clinical benefit derived from therapies that reduce LDL cholesterol. Methods We conducted a meta-analysis of the association between a common Trp719Arg polymorphism in the kinesin-like protein 6 (KIF6) gene and the risk of cardiovascular disease (CVD), and a meta-regression analysis to measure the effect modification of this polymorphism on the association between LDL cholesterol and the risk of CVD. We used this measure of genetic effect modification to predict the expected difference in clinical benefit among KIF6 719Arg allele carriers and non-carriers in response to therapies that reduce LDL cholesterol. We then conducted a meta-analysis of statin trials to compare the expected difference in clinical benefit with the observed difference during treatment with a statin. Results In a meta-analysis involving 144,931 participants, the KIF6 719Arg allele was not associated with the relative risk (RR) of CVD (RR: 1.02, 95%CI: 0.98–1.07, p = 0.288). Meta-regression analysis involving 88,535 participants, however, showed that the 719Arg allele appears to influence the effect of LDL cholesterol on the risk of CVD. KIF6 carriers experienced a 13% greater reduction in the risk of CVD per mmol/L decrease in LDL cholesterol than non-carriers. We interpreted this difference as the expected difference in clinical benefit among KIF6 carriers and non-carriers in response to therapies that lower LDL cholesterol. The difference in clinical benefit predicted by the increased vulnerability to LDL cholesterol among KIF6 carriers (ratio of RR: 0.87, 95%CI: 0.80–0.94, p = 0.001) agreed very closely with the observed difference among 50,060 KIF6 carriers and non-carriers enrolled in 8 randomized trials of statin therapy (ratio of RR: 0.87, 95%CI: 0.77–0.99, p = 0.038). Conclusion The KIF6 719Arg allele increases vulnerability to LDL cholesterol and thereby influences the expected clinical benefit of therapies that reduce LDL cholesterol.
What Role Can Propinquity Play in the Development of New National Allegiances? Immigrant Latinos Establishing Ties to the United States through Out-Group Contact  [PDF]
Christopher Olds
Advances in Applied Sociology (AASoci) , 2012, DOI: 10.4236/aasoci.2012.21002
Abstract: Contact theory has primarily been applied to the study of interactions between Blacks and Whites, with particular emphasis on changes in the attitudes of Whites towards Blacks. How individual contact with an out-group can influence not just attitudes, but also actual behavior, has not been thoroughly explored. Through an analysis of the 2006 Latino National Survey, using a measure that contrasts the intensity of individual social interaction with various ethnic and racial groups, the study shows that a high intensity of friendly social contact with African-Americans increases the likelihood Latino immigrants will establish a closer link to the social and political structures of the United States. Latino immigrants are potentially experiencing movement towards deprovincialization through high levels of friendly social interaction with African-Americans. The development of friendly personal interactions with an out-group stigmatized in the mother country can help Latino immigrants develop an optimistic view of life in the host country.
Net primary production and carbon cycling in coast redwood forests of central California  [PDF]
Christopher Potter
Open Journal of Ecology (OJE) , 2012, DOI: 10.4236/oje.2012.23018
Abstract: A simulation model to estimate net primary productivity (NPP) has been combined with in situ measurements of soil carbon dioxide (CO2) emissions and leaf litter pools in three coast redwood forest stands on the central California coast. Monthly NPP was predicted from the CASA model using 250-meter resolution vegetation index (VI) inputs. Annual NPP was predicted to vary from 380 g·C·m-2·yr-1 to 648 g·C·m-2·yr-1 at central coast redwood sites over the years 2007 to 2010. Measured soil respiration rates at between 0.5 to 2.2 g·C·m-2·d-1 were slightly below the range of measurements previously reported for a second-growth mixed (redwood and Douglas-fir) conifer forests. Although warm monthly temperatures at the southern-most redwood forest sites evidently results in elevated stress levels to sustained redwood growth into the dry summer months of June and July, these redwood stands appear to sequester CO2 from that atmosphere into forest biomass for a net positive ecosystem carbon balance each year.
Ten Years of Vegetation Change in Northern California Marshlands Detected Using Landsat Satellite Image Analysis  [PDF]
Christopher Potter
Journal of Water Resource and Protection (JWARP) , 2013, DOI: 10.4236/jwarp.2013.55048

The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) methodology was applied to detect changes in perennial vegetation cover at marshland sites in Northern California reported to have undergone restoration between 1999 and 2009. Results showed extensive contiguous areas of restored marshland plant cover at 10 of the 14 sites selected. Gains in either woody shrub cover and/or from a recovery of herbaceous cover that remains productive and evergreen on a year round basis could be mapped out from the image results. However, LEDAPS may not be highly sensitive changes in wetlands that have been restored mainly with seasonal herbaceous cover (e.g., vernal pools), due to the ephemeral nature of the plant greenness signal. Based on this evaluation, the LEDAPS methodology would be capable of fulfilling a pressing need for consistent, continual, low-cost monitoring of changes in marshland ecosystems of the Pacific Flyway.

Ex Post Efficient Set Mathematics  [PDF]
Christopher Adcock
Journal of Mathematical Finance (JMF) , 2013, DOI: 10.4236/jmf.2013.31A019

This paper considers efficient set mathematics for the case where the covariance matrix of asset returns is assumed known but ex ante the vector of expected returns is replaced by an estimated or forecast value. It is shown that the ex post mean and variance differ from the standard results. Consequently the maximum Sharpe ratio portfolio also differs from the standard result. However, even with uncertainty about the vector of expected returns, subject to the assumptions made about the joint distribution of actual returns and estimated mean returns, ex post Sharpe ratio maximisers hold the ex post market portfolio. The properties of the zero beta portfolio are similar to the standard results leading to a capital market line. The ex post Capital Asset Pricing Model incorporates an intercept and the betas are not the same as those computed ex ante. The results are illustrated with an example.


Mortality and motivations: Clinicians’ integrity engaging death within complex cultural context  [PDF]
Christopher Jenner
Open Journal of Nursing (OJN) , 2013, DOI: 10.4236/ojn.2013.31011

This broad ranging discussion examines the clinical encounter and deconstructs psychological and cultural context and implications, finally honoring the comprehensive awareness that the clinician requires for best practice in encountering mortality. Clinicians engage client disease and dying presentions, and ultimate mortality. Communicating mortality openly or subliminally is not always conscious. Mortality awareness can produce stress and untoward behaviors. Psychological mortality avoidance, citing Kierke-gaard’s existential paradox, and the death (in both senses) of Joseph Campbell’s cultural hero illumine socio-cultural elements including the elusive “good death”, sequestration of death from society, and the concept of managing death in volume. Cultural diversity awareness and the concept of transcendence clarify outlier and hybrid cultural client presentations demanding maximal clinician flexibility. Mortality Salience Theory predicts contracted world view when confronted with mortality, demanding sensitivity to a variety of responses. A hospice approach may not be best for some, despite a lack of new alternative to that paradigm. Managing mortality awareness and dying stresses the clinician by the weight and loneliness of perhaps unpopular decisions, by responsibility to community in managing death, and by the take-home exposure of the clinician’s family to the concept of death and mortality. Aptitude for managing death depends on clinician self awareness and a good match with practice venue. Clinician integrity and consciousness of motives and responses allows engagement or deferral as necessary without threat to identity.

Regional Analysis of NASA Satellite Greenness Trends for Ecosystems of Arctic Alaska  [PDF]
Christopher Potter
International Journal of Geosciences (IJG) , 2014, DOI: 10.4236/ijg.2014.59085

Trends in the growing season MODerate resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) time-series were analyzed for the period from 2000 to 2010 to understand landscape-level patterns of vegetation change in ecosystems of arctic Alaska. We compared datasets for vegetation cover types, wetland cover classes, wildfire boundaries since the 1940s, permafrost type, and elevation to identify the most likely combination of factors driving regional changes in habitat quality and ecosystem productivity. Approximately 57% of all arctic ecosystem areas in Alaska were detected with significant (p < 0.05) positive or negative MODIS growing season EVI trends from 2000 to 2010. Nearly all (99%) of these ecosystem areas (covering 178,050 km2) were detected with significant positive growing season EVI trends. The vast majority of the arctic Alaska region detected with significant positive growing season EVI trends was classified as upland tundra cover, although non-forested wetlands (marshes, bogs, fens, and floodplains) were co-located on 8% of that area. Herbaceous wetlands were co-located on 55% of the total area detected with significant negative growing season EVI trends, mostly on the arctic coastal plain and foothills. This evidence supports the hypothesis that temperature (warming) has markedly enhanced the rates of upland tundra vegetation growth across most of arctic Alaska over recent years.

Geographic Analysis of Burn Severity for the 2013 California Rim Fire  [PDF]
Christopher Potter
Natural Resources (NR) , 2014, DOI: 10.4236/nr.2014.511052
Analysis of Landsat imagery was applied to classify burn severity within the 2013 Rim Fire area using the relative difference normalized burn ratio (RdNBR). Results showed 53,220 ha in the High Burn Severity (HBS) class and another 34,214 ha in the Moderate Burn Severity (MBS) class. Within Yosemite National Park, 12,084 ha were detected by RdNBR analysis in the HBS class and another 11,089 ha in the MBS class. The most typical ecosystem habitat detected within the HBS class was Ponderosa pine—Mixed Conifer forest, between the elevations of 1000 and 2000 meters or on slopes between 5 and 30 percent. Most of the HBS areas were located in areas where high levels of pre-fire fuels were quantified by 2013 Landsat vegetation index (NDVI) values between 500 and 800. The Low Burn Severity (LBS) class covered a higher fraction of areas where the duration since last fire (YSF) was less than 25 years, compared to the HBS class, which covered a higher fraction of areas where the YSF was greater than 60 years.
Diglossia in the Arab World
—Educational Implications and Future Perspectives

Christopher Horn
Open Journal of Modern Linguistics (OJML) , 2015, DOI: 10.4236/ojml.2015.51009
Abstract: This essay will offer an introduction to the long-debated issue of diglossia in the Arabic-speaking world, together with an overview of some of the effects it brings about within the Arab society against the background of the governing Islamic creed. After a definition of the issue, backed by the most relevant, related academic literature, a brief overview will be offered of the social setting in which this situation has perpetuated itself to this day. The author will then proceed to assess the impact of diglossia on Arab youth, nowadays, with an eye on educational concerns, and will conclude with a tentative speculation on the future of Arabic as a language, in hopes to inspire further academic endeavor.
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