78 research outputs found
Behavior of Poly-A onto Kaolin
A combination of geochemical variables is necessary to explain the origin of life on Earth. Thus, in this work the sorption of Poly-A on a clay mineral (kaolinite) was studied to get an insight about the sorption capacity at different times and pH values, as well as to confirm the capabilities of the clay to protect the sorbate from an external source of ionizing radiation. Poly-A presented a high percentage of sorption in the clay, especially in acidic environments, and this percentage sharply decrease in alkaline media. On the other hand, Poly-A’s recovery was higher in the system with clay, confirming its protection role
Using concepts of shoot growth and architecture to understand and predict responses of peach trees to pruning
International audienceOne definition of horticulture is "the art of cultivating garden plants" and pruning is a horticultural practice that is traditionally approached as more of an art than a science. This is largely because of the complexity of tree growth and development and a lack of general understanding and appreciation about the processes involved in governing shoot and tree growth and development. However recent tree architectural studies have provided systematic analyses of the shoot growth and statistical and dynamic simulation models have been developed that predict tree development and responses to pruning based on scientific concepts. These concepts include apical dominance (and its subcomponents; correlative inhibition, apical control and shoot epinasty); prolepsis and syllepsis; preformation and neoformation; epicormic shoot formation and plastochron (leaf emergence rates). In this paper we will discuss how many of these concepts can be combined with hidden semi-Markov chain models of shoot bud fates and a simulation model of source-sink interactions in peach trees (L-PEACH) to understand and predict natural development of peach trees and their responses to pruning. The results of these modeling efforts help explain the architectural and physiological basis of several common, empirically-based pruning systems used in California. These concepts also provide an understanding of the limitations of relying primarily on the use of pruning to control size of trees growing on commonly used invigorating rootstocks. This research demonstrates how computer simulation modeling can be used to test and analyze interactions between environmental factors and management practices in determining patterns of tree growth and development
Isolation and Genetic Analysis of Bovine Viral Diarrhea Virus from Infected Cattle in Indiana
Species and biotype distribution was determined in 44 bovine viral diarrhea virus- (BVDV-) positive samples submitted to the Animal Disease Diagnostic Laboratory (ADDL) in Indiana during 2006–2008. BVDV RNA was detected in the 5′-untranslated region and Npro region using reverse transcriptase PCR followed by sequencing analysis of the PCR product. Additionally, cases were classified into one of six categories according to history and/or lesions: acute symptomatic, hemorrhagic, respiratory distress, reproductive, persistent infection (PI), and mucosal disease (MD). Of 44 BVDV-positive samples, 33 were noncytopathic (ncp), 10 were cytopathic (cp), and one presented both ncp and cp biotypes. Sequencing analysis demonstrated that all samples belonged to BVDV-1a, BVDV-1b, or BVDV-2. The most common isolate was ncp BVDV-1b, (44%) followed by ncp BVDV-2a (24%). Among the six categories, respiratory clinical signs were the most common (36%) followed by PI (25%) and MD (16%)
Enhancing organizational capacity to provide cancer control programs among Latino churches: design and baseline findings of the CRUZA Study
Abstract Background Faith-based organizations (FBOs) have been successful in delivering health promotion programs for African Americans, though few studies have been conducted among Latinos. Even fewer have focused on organizational change, which is required to sustain community-based initiatives. We hypothesized that FBOs serving Latinos would be more likely to offer evidence-based strategies (EBS) for cancer control after receiving a capacity enhancement intervention to implement health programs, and designed the CRUZA trial to test this hypothesis. This paper describes the CRUZA design and baseline findings. Methods We identified Catholic parishes in Massachusetts that provided Spanish-language mass (n = 65). A baseline survey assessed organizational characteristics relevant to adoption of health programs, including readiness for adoption, “fit” between innovation and organizational mission, implementation climate, and organizational culture. In the next study phase, parishes that completed the baseline assessment will be recruited to a randomized cluster trial, with the parish as the unit of analysis. Both groups will receive a Program Manual and Toolkit. Capacity Enhancement parishes will also be offered technical support, assistance forming health committees and building inter-institutional partnerships, and skills-based training. Results Of the 49 parishes surveyed at baseline (75%), one-third (33%) reported having provided at least one health program in the prior year. However, only two program offerings were cancer-specific. Nearly one-fifth (18%) had an active health ministry. There was a high level of organizational readiness to adopt cancer control programs, high congruence between parish missions and CRUZA objectives, moderately conducive implementation climates, and organizational cultures supportive of CRUZA programming. Having an existing health ministry was significantly associated with having offered health programs within the past year. Relationships between health program offerings and other organizational characteristics were not statistically significant. Conclusions Findings suggest that many parishes do not offer cancer control programs, yet many may be ready to do so. However, the perceptions about existing organizational practices and policies may not be conducive to program initiation. A capacity enhancement intervention may hold promise as a means of increasing health programming. The efficacy of such an intervention will be tested in phase two of this study
Predictors of Ips confusus Outbreaks During a Record Drought in Southwestern USA: Implications for Monitoring and Management
In many ecosystems the effects of disturbance can be cryptic and disturbance may vary in subtle spatiotemporal ways. For instance, we know that bark beetle outbreaks are more frequent in temperate forests during droughts; however, we have little idea about why they occur in some locations and not others. Understanding biotic and abiotic factors promoting bark beetle outbreaks can be critical to predicting and responding to pest outbreaks. Here we address the environmental factors which are associated with Ips confusus outbreaks during the 2002 widespread drought within the distribution range of pinyon pine woodlands in Arizona. We used univariate statistics to test if whether tree characteristics, other herbivores, stand properties, soil type, wind, and topography were associated with I. confusus outbreak, and logistic regression to create a predictive model for the outbreaks. We found that I. confusus attacks occur in low elevation stands on steeper slopes, where favorable winds for I. confusus dispersion occur. I. confusus select larger trees, in high density stands with understory shrubs that exhibit phenotypic traits characteristic of resistance to stem-boring moths. The model was highly accurate, and explained 95% of the variability in occurrence (98% of the absences and 95% of the presences). Accurate prediction of the impacts of disturbance allow us to anticipate, minimize or mitigate for and eventually counteract its effects, especially those affecting diversity and ecosystem function. Identification of outbreak risk areas can guide regional and national management towards the reduction of infestation risk and enhancing conservation of pinyon-juniper woodlands
Seasonal changes of whole root system conductance by a drought-tolerant grape root system
The role of root systems in drought tolerance is a subject of very limited information compared with above-ground responses. Adjustments to the ability of roots to supply water relative to shoot transpiration demand is proposed as a major means for woody perennial plants to tolerate drought, and is often expressed as changes in the ratios of leaf to root area (AL:AR). Seasonal root proliferation in a directed manner could increase the water supply function of roots independent of total root area (AR) and represents a mechanism whereby water supply to demand could be increased. To address this issue, seasonal root proliferation, stomatal conductance (gs) and whole root system hydraulic conductance (kr) were investigated for a drought-tolerant grape root system (Vitis berlandieri×V. rupestris cv. 1103P) and a non-drought-tolerant root system (Vitis riparia×V. rupestris cv. 101-14Mgt), upon which had been grafted the same drought-sensitive clone of Vitis vinifera cv. Merlot. Leaf water potentials (ψL) for Merlot grafted onto the 1103P root system (–0.91±0.02 MPa) were +0.15 MPa higher than Merlot on 101-14Mgt (–1.06±0.03 MPa) during spring, but dropped by approximately –0.4 MPa from spring to autumn, and were significantly lower by –0.15 MPa (–1.43±0.02 MPa) than for Merlot on 101-14Mgt (at –1.28±0.02 MPa). Surprisingly, gs of Merlot on the drought-tolerant root system (1103P) was less down-regulated and canopies maintained evaporative fluxes ranging from 35–20 mmol vine−1 s−1 during the diurnal peak from spring to autumn, respectively, three times greater than those measured for Merlot on the drought-sensitive rootstock 101-14Mgt. The drought-tolerant root system grew more roots at depth during the warm summer dry period, and the whole root system conductance (kr) increased from 0.004 to 0.009 kg MPa−1 s−1 during that same time period. The changes in kr could not be explained by xylem anatomy or conductivity changes of individual root segments. Thus, the manner in which drought tolerance was conveyed to the drought-sensitive clone appeared to arise from deep root proliferation during the hottest and driest part of the season, rather than through changes in xylem structure, xylem density or stomatal regulation. This information can be useful to growers on a site-specific basis in selecting rootstocks for grape clonal material (scions) grafted to them
Exploiting social influence to magnify population-level behaviour change in maternal and child health: study protocol for a randomised controlled trial of network targeting algorithms in rural Honduras
Introduction: Despite global progress on many measures of child health, rates of neonatal mortality remain high in the developing world. Evidence suggests that substantial improvements can be achieved with simple, low-cost interventions within family and community settings, particularly those designed to change knowledge and behaviour at the community level. Using social network analysis to identify structurally influential community members and then targeting them for intervention shows promise for the implementation of sustainable community-wide behaviour change. Methods and analysis We will use a detailed understanding of social network structure and function to identify novel ways of targeting influential individuals to foster cascades of behavioural change at a population level. Our work will involve experimental and observational analyses. We will map face-to-face social networks of 30 000 people in 176 villages in Western Honduras, and then conduct a randomised controlled trial of a friendship-based network-targeting algorithm with a set of well-established care interventions. We will also test whether the proportion of the population targeted affects the degree to which the intervention spreads throughout the network. We will test scalable methods of network targeting that would not, in the future, require the actual mapping of social networks but would still offer the prospect of rapidly identifying influential targets for public health interventions. Ethics and dissemination The Yale IRB and the Honduran Ministry of Health approved all data collection procedures (Protocol number 1506016012) and all participants will provide informed consent before enrolment. We will publish our findings in peer-reviewed journals as well as engage non-governmental organisations and other actors through venues for exchanging practical methods for behavioural health interventions, such as global health conferences. We will also develop a ‘toolkit’ for practitioners to use in network-based intervention efforts, including public release of our network mapping software. Trial registration number NCT02694679; Pre-results
Genotype-Phenotype Correlation in NF1: Evidence for a More Severe Phenotype Associated with Missense Mutations Affecting NF1 Codons 844–848
Neurofibromatosis type 1 (NF1), a common genetic disorder with a birth incidence of 1:2,000–3,000, is characterized by a highly variable clinical presentation. To date, only two clinically relevant intragenic genotype-phenotype correlations have been reported for NF1 missense mutations affecting p.Arg1809 and a single amino acid deletion p.Met922del. Both variants predispose to a distinct mild NF1 phenotype with neither externally visible cutaneous/plexiform neurofibromas nor other tumors. Here, we report 162 individuals (129 unrelated probands and 33 affected relatives) heterozygous for a constitutional missense mutation affecting one of five neighboring NF1 codons—Leu844, Cys845, Ala846, Leu847, and Gly848—located in the cysteine-serine-rich domain (CSRD). Collectively, these recurrent missense mutations affect ∼0.8% of unrelated NF1 mutation-positive probands in the University of Alabama at Birmingham (UAB) cohort. Major superficial plexiform neurofibromas and symptomatic spinal neurofibromas were more prevalent in these individuals compared with classic NF1-affected cohorts (both p < 0.0001). Nearly half of the individuals had symptomatic or asymptomatic optic pathway gliomas and/or skeletal abnormalities. Additionally, variants in this region seem to confer a high predisposition to develop malignancies compared with the general NF1-affected population (p = 0.0061). Our results demonstrate that these NF1 missense mutations, although located outside the GAP-related domain, may be an important risk factor for a severe presentation. A genotype-phenotype correlation at the NF1 region 844–848 exists and will be valuable in the management and genetic counseling of a significant number of individuals
Non-medical reasons for colectomy among ulcerative colitis patients
Approximately 16% of ulcerative colitis (UC) patients will have a colectomy within 10 years of their diagnosis of UC. Due to the high morbidity and mortality associated with colectomy procedures, clinicians and patients strive to avoid surgery. The decline of colectomy rates over the last 6 decades has been mainly attributed to advances in medical management of UC. Clostridium difficile infection and colorectal neoplasia have also been associated with driving the risk of colectomy. This dissertation focuses on describing the effect of C. difficile and colorectal neoplasia on the risk of colectomy for UC patients. Chapters 2 and 3 establish the cumulative risk of acquiring C. difficile infection after the diagnosis of UC and demonstrated that C. difficile infections increase the short- and long-term risk of colectomy. Further, both Chapters 2 and 3 demonstrate that C. difficile infections increased the risk of postoperative complications following colectomy for UC. Chapter 4 demonstrate that the incidence of colectomy for colorectal dysplasia and cancer has remained stable over time, and showed that the observed decrease in colectomy rates is most likely due to a decrease in colectomies from medically refractory disease. Finally, Chapter 5 determined the cost-effectiveness of different surveillance colonoscopy intervals for colorectal dysplasia among a subgroup of inflammatory bowel disease (IBD) patients with a higher risk of developing colorectal dysplasia and cancer; i.e., patients with IBD and primary sclerosing cholangitis (PSC)
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