Caracterização de Rhizoctonia solani Kühn, agente causal da mela da soja (Glycine max (L.) Merrill), seleção de genótipos e controle químico

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

Antiresorptive drugs (bisphosphonates), atypical fractures and rebound effect: new evidence of similitude

Background: Homeopathy is based on treatment by similitude ('like cures like') administering to sick individuals substances that cause similar symptoms in healthy individuals, employing the secondary and paradoxical action of the organism as therapeutic response. This vital or homeostatic reaction of the organism can be scientifically explained by the rebound effect of drugs, resulting in worsening of symptoms after suspension of treatment. Bisphosphonates (BPs) reduce 'typical' fractures in patients with osteoporosis, but recent studies report 'atypical' fractures of the femur after stopping the BPs, a rebound effect may be the causal mechanism. Method: Review of the literature concerning the relationship between atypical femoral fractures and antiresorptive drugs (bisphosphonates), identifying the pathogenesis of this adverse event. Results: Several studies have described multiple cases of 'atypical' low-impact subtrochanteric stress fractures or complete fractures of the femur. These fractures are often bilateral, preceded by pain in the affected thigh, may have a typical X-ray appearance, and may delayed healing. Rebound of osteoclastic activity after suspension of antiresorptive drugs is a plausible mechanism to explain this phenomenon. Conclusion: As for other classes of drugs, the rebound effect of antiresorptive drugs supports Hahnemann's similitude principle (primary action of the drugs followed by secondary and opposite action of the organism), and clarifies this 'unresolved' issue. Unfortunately, the rebound effect is little discussed among health professionals, depriving them of important knowledge ensure safe management of drugs. Homeopathy (2012) 101, 231-242.

Effect of fungicides and alternative products in control of anthracnose and black spot of guava

This work aimed to evaluate the efficiency of fungicides in controlling in vitro and in vivo the causal agents of anthracnose (Colletotrichum gloeosporioides and C. acutatum) and black spot (Guignardia psidii) and evaluate the effect of alternative products to control these diseases. Inhibition of mycelial growth of the pathogens was evaluated for ten fungicides at concentrations of 1, 10 and 100 mg L-1 of active ingredient in potato-dextrose-agar medium. The effectiveness of the fungicides azoxystrobin + difenoconazole, cyproconazole, pyraclostrobin, tebuconazole and tebuconazole + trifloxystrobin in controlling disease incidence and severity of anthracnose, through applications in the field, was measured in fruits collected at three stages of maturation, according to the skin color ( dark green, light green and yellowish green). In postharvest dipping of fruits, the products evaluated were citric acid, peracetic acid, salicylic acid, sodium bicarbonate, chlorine dioxide, Ecolife (R) and chitosan. The fungicides azoxystrobin + difenoconazole, pyraclostrobin, tebuconazole and trifloxystrobin + tebuconazole were highly effective in inhibiting the in vitro mycelial growth of G. psidii and moderately to highly effective in inhibiting C. acutatum and C. gloeosporioides. In field conditions, the fungicide azoxystrobin + difenoconazole was effective in controlling anthracnose and black spot in fruit at three maturity stage ( skin color yellowish green). The alternative products tested were ineffective in the curative control of anthracnose and early blight at postharvest of guava.

Is the allegiance effect an epiphenomenon of true efficacy differences between treatments? a meta-analysis

Many meta-analyses of comparative outcome studies found a substantial association of researcher allegiance (RA) and relative treatment effects. Therefore, RA is regarded as a biasing factor in comparative outcome research (RA bias hypothesis). However, the RA bias hypothesis has been criticized as causality might be reversed. That is, RA might be a reflection of true efficacy differences between treatments (true efficacy hypothesis). Consequently, the RA-outcome association would not be indicative of bias but an epiphenomenon of true efficacy differences. This meta-analysis tested the validity of the true efficacy hypothesis. This was done by controlling the RA-outcome association for true efficacy differences by restricting analysis to direct comparisons of treatments with equivalent efficacy. We included direct comparisons of different versions of trauma-focused therapy (TFT) in the treatment of posttraumatic stress disorder (PTSD). RA was measured from the research reports. Relative effect sizes for symptoms of PTSD were calculated. Random effects meta-regression was conducted. Twenty-nine comparisons of TFTs from 20 studies were identified. Initial heterogeneity among relative effect sizes was low. RA was a significant predictor of outcome and explained 12% of the variance in outcomes. The true efficacy hypothesis predicted the RA-outcome association to be zero; however, a substantial association was found. Thus, this study does not support the true efficacy hypothesis. Given findings from psychotherapy research and other fields that support a biasing influence of researcher preferences, RA should be regarded as a causal factor and conceptualized as a threat to the validity of conclusions from comparative outcome studies.

The effect of efavirenz versus nevirapine-containing regimens on immunologic, virologic and clinical outcomes in a prospective observational study

OBJECTIVE: To compare regimens consisting of either efavirenz or nevirapine and two or more nucleoside reverse transcriptase inhibitors (NRTIs) among HIV-infected, antiretroviral-naive, and AIDS-free individuals with respect to clinical, immunologic, and virologic outcomes. DESIGN: Prospective studies of HIV-infected individuals in Europe and the US included in the HIV-CAUSAL Collaboration. METHODS: Antiretroviral therapy-naive and AIDS-free individuals were followed from the time they started an NRTI, efavirenz or nevirapine, classified as following one or both types of regimens at baseline, and censored when they started an ineligible drug or at 6 months if their regimen was not yet complete. We estimated the 'intention-to-treat' effect for nevirapine versus efavirenz regimens on clinical, immunologic, and virologic outcomes. Our models included baseline covariates and adjusted for potential bias introduced by censoring via inverse probability weighting. RESULTS: A total of 15 336 individuals initiated an efavirenz regimen (274 deaths, 774 AIDS-defining illnesses) and 8129 individuals initiated a nevirapine regimen (203 deaths, 441 AIDS-defining illnesses). The intention-to-treat hazard ratios [95% confidence interval (CI)] for nevirapine versus efavirenz regimens were 1.59 (1.27, 1.98) for death and 1.28 (1.09, 1.50) for AIDS-defining illness. Individuals on nevirapine regimens experienced a smaller 12-month increase in CD4 cell count by 11.49 cells/mul and were 52% more likely to have virologic failure at 12 months as those on efavirenz regimens. CONCLUSIONS: Our intention-to-treat estimates are consistent with a lower mortality, a lower incidence of AIDS-defining illness, a larger 12-month increase in CD4 cell count, and a smaller risk of virologic failure at 12 months for efavirenz compared with nevirapine.

On Causal Mediation Analysis with a Survival Outcome

Suppose that having established a marginal total effect of a point exposure on a time-to-event outcome, an investigator wishes to decompose this effect into its direct and indirect pathways, also know as natural direct and indirect effects, mediated by a variable known to occur after the exposure and prior to the outcome. This paper proposes a theory of estimation of natural direct and indirect effects in two important semiparametric models for a failure time outcome. The underlying survival model for the marginal total effect and thus for the direct and indirect effects, can either be a marginal structural Cox proportional hazards model, or a marginal structural additive hazards model. The proposed theory delivers new estimators for mediation analysis in each of these models, with appealing robustness properties. Specifically, in order to guarantee ignorability with respect to the exposure and mediator variables, the approach, which is multiply robust, allows the investigator to use several flexible working models to adjust for confounding by a large number of pre-exposure variables. Multiple robustness is appealing because it only requires a subset of working models to be correct for consistency; furthermore, the analyst need not know which subset of working models is in fact correct to report valid inferences. Finally, a novel semiparametric sensitivity analysis technique is developed for each of these models, to assess the impact on inference, of a violation of the assumption of ignorability of the mediator.

Prognostic relevance of coronary collateral function: confounded or causal relationship?

OBJECTIVE To expand the limited information on the prognostic impact of quantitatively obtained collateral function in patients with coronary artery disease (CAD) and to estimate causality of such a relation. DESIGN Prospective cohort study with long-term observation of clinical outcome. SETTING University Hospital. PATIENTS One thousand one hundred and eighty-one patients with chronic stable CAD undergoing 1771 quantitative, coronary pressure-derived collateral flow index measurements, as obtained during a 1-min coronary balloon occlusion (CFI is the ratio between mean distal coronary occlusive pressure and mean aortic pressure both subtracted by central venous pressure). Subgroup of 152 patients included in randomised trials on the longitudinal effect of different arteriogenic protocols on CFI. INTERVENTIONS Collection of long-term follow-up information on clinical outcome. MAIN OUTCOME MEASURES All-cause mortality and major adverse cardiac events. RESULTS Cumulative 15-year survival rate was 48% in patients with CFI<0.25 and 65% in the group with CFI≥0.25 (p=0.0057). Cumulative 10-year survival rate was 75% in patients without arteriogenic therapy and 88% (p=0.0482) in the group with arteriogenic therapy and showing a significant increase in CFI at follow-up. By proportional hazard analysis, the following variables predicted increased all-cause mortality: age, low CFI, left ventricular end-diastolic pressure and number of vessels with CAD. CONCLUSIONS A well-functioning coronary collateral circulation independently predicts lowered mortality in patients with chronic CAD. This relation appears to be causal, because augmented collateral function by arteriogenic therapy is associated with prolonged survival.

The effect of cumulating exposure to abacavir on the risk of cardiovascular disease events in patients from the Swiss HIV Cohort Study.

BACKGROUND Patients with HIV exposed to the antiretroviral drug abacavir may have an increased risk of cardiovascular disease (CVD). There is concern that this association arises because of a channelling bias. Even if exposure is a risk, it is not clear how that risk changes as exposure cumulates. METHODS We assess the effect of exposure to abacavir on the risk of CVD events in the Swiss HIV Cohort Study. We use a new marginal structural Cox model to estimate the effect of abacavir as a flexible function of past exposures while accounting for risk factors that potentially lie on a causal pathway between exposure to abacavir and CVD. RESULTS 11,856 patients were followed for a median of 6.6 years; 365 patients had a CVD event (4.6 events per 1000 patient years). In a conventional Cox model, recent - but not cumulative - exposure to abacavir increased the risk of a CVD event. In the new marginal structural Cox model, continued exposure to abacavir during the past four years increased the risk of a CVD event (hazard ratio 2.06, 95% confidence interval 1.43-2.98). The estimated function for the effect of past exposures suggests that exposure during the past 6 to 36 months caused the greatest increase in risk. CONCLUSIONS Abacavir increases the risk of a CVD event: the effect of exposure is not immediate, rather the risk increases as exposure cumulates over the past few years. This gradual increase in risk is not consistent with a rapidly acting mechanism, such as acute inflammation.

Methodological Report on Kaul and Wolf's Working Papers on the Effect of Plain Packaging on Smoking Prevalence in Australia and the Criticism Raised by OxyRomandie

This report contains a methodological assessment of two working papers by Ashok Kaul and Michael Wolf on the effect of plain packaging on smoking prevalence in Australia and the criticism raised against these working papers by OxyRomandie. First, the potential of the data used by Kaul and Wolf for identifying causal effects is discussed. Second, a reanalysis of the data is provided. Third, the criticism raised by OxyRomandie is commented.

Evaluation of the causal pathways through which subjective norms influence mammography intention and stage of change in a national sample of women veterans

Few studies have investigated causal pathways linking psychosocial factors to each other and to screening mammography. Conflicting hypotheses exist in the theoretic literature regarding the role and importance of subjective norms, a person's perceived social pressure to perform the behavior and his/her motivation to comply. The Theory of Reasoned Action (TRA) hypothesizes that subjective norms directly affect intention; while the Transtheoretical Model (TTM) hypothesizes that attitudes mediate the influence of subjective norms on stage of change. No one has examined which hypothesis best predicts the effect of subjective norms on mammography intention and stage of change. Two statistical methods are available for testing mediation, sequential regression analysis (SRA) and latent variable structural equation modeling (LVSEM); however, software to apply LVSEM to dichotomous variables like intention has only recently become available. No one has compared the methods to determine whether or not they yield similar results for dichotomous variables. ^ Study objectives were to: (1) determine whether the effect of subjective norms on mammography intention and stage of change are mediated by pros and cons; and (2) compare mediation results from the SRA and LVSEM approaches when the outcome is dichotomous. We conducted a secondary analysis of data from a national sample of women veterans enrolled in Project H.O.M.E. (H&barbelow;ealthy O&barbelow;utlook on the M&barbelow;ammography E&barbelow;xperience), a behavioral intervention trial. ^ Results showed that the TTM model described the causal pathways better than the TRA one; however, we found support for only one of the TTM causal mechanisms. Cons was the sole mediator. The mediated effect of subjective norms on intention and stage of change by cons was very small. These findings suggest that interventionists focus their efforts on reducing negative attitudes toward mammography when resources are limited. ^ Both the SRA and LVSEM methods provided evidence for complete mediation, and the direction, magnitude, and standard errors of the parameter estimates were very similar. Because SRA parameter estimates were not biased toward the null, we can probably assume negligible measurement error in the independent and mediator variables. Simulation studies are needed to further our understanding of how these two methods perform under different data conditions. ^

What is the Impact of the Underserved Pathway program on Entering an Underserved Family Medicine Residency? A Comparison of Three Approaches for Estimating the Average Treatment Effect

Thesis (Master's)--University of Washington, 2016-06

The effect of forearm support on musculoskeletal discomfort during call centre work

Using a computer keyboard with the forearms unsupported has been proposed as a causal factor for neck/shoulder and arm/hand diagnoses. Recent laboratory and field studies have demonstrated that forearm support might be preferable to working in the traditional floating posture. The aim of this study was to determine whether providing forearm Support when using a normal computer workstation would decrease musculoskeletal discomfort in intensive computer users in a call centre. A randomised controlled study (n = 59), of 6 weeks duration was conducted. Thirty participants (Group 1) were allocated to forearm support using the desk surface with the remainder (Group 2) acting as a control group. At 6 weeks, the control group was also set up with forearm support. Both groups were then monitored for another 6 weeks. Questionnaires were used at 1, 6 and 12 weeks to obtain information about discomfort, workstation setup, working posture and comfort. Nine participants (Group 1 n = 6, Group 2 n = 3) withdrew within a week of commencing forearm support either due to discomfort or difficulty in maintaining the posture. At 6 weeks, the group using forearm support generated significantly fewer reports of discomfort in the neck and back, although the difference between the groups was not statistically significant. At 12 weeks, there were fewer reports of neck, back and wrist discomfort when preintervention discomfort was compared with post intervention discomfort. These findings indicate that for the majority of users, forearm support may be preferable to the floating Posture implicit in current guidelines for computer workstation setup. (C) 2004 Elsevier Ltd. All rights reserved.

Are pathological lesions in neurodegenerative disorders the cause or the effect of the degeneration?

Pathological lesions in the form of extracellular protein deposits, intracellular inclusions and changes in cell morphology occur in the brain in the majority of neurodegenerative disorders. Studies of the presence, distribution, and molecular determinants of these lesions are often used to define individual disorders and to establish the mechanisms of lesion pathogenesis. In most disorders, however, the relationship between the appearance of a lesion and the underlying disease process is unclear. Two hypotheses are proposed which could explain this relationship: (i) lesions are the direct cause of the observed neurodegeneration ('causal' hypothesis); and (ii) lesions are a reaction to neurodegeneration ('reaction' hypothesis). These hypotheses are considered in relation to studies of the morphology and molecular determinants of lesions, the effects of gene mutations, degeneration induced by head injury, the effects of experimentally induced brain lesions, transgenic studies and the degeneration of anatomical pathways. The balance of evidence suggests that in many disorders, the appearance of the pathological lesions is a reaction to degenerative processes rather than being their cause. Such a conclusion has implications both for the classification of neurodegenerative disorders and for studies of disease pathogenesis.

Innováció és dinamizmus. Kölcsönhatás a rendszerek és a technikai haladás között = Innovation and dynamism. Reciprocal effect between systems and technical advance

A posztszocialista átalakulással foglalkozó irodalom rendszerint az átmenet politikai, gazdasági és társadalmi oldalával foglalkozik, holott az elmúlt húsz évben fontos változások mentek végbe a technikai haladás terén is. A kapitalizmus egyik fő erénye a dinamizmus, a vállalkozás, az innovációs folyamat erős ösztönzése. Valamennyi (polgári célokra használt) forradalmian új terméket a kapitalista rendszer hozta létre, a szocialista rendszer legfeljebb katonai rendeltetésű új termékekkel tudott előállni. A cikk azt elemzi, hogy mennyiben magyarázható ez a mélyreható különbség a két rendszer veleszületett hajlamaival, alapvető tulajdonságaival. Az új termékek térhódítása (köztük a számítógép, a mobiltelefon, az internet, az információs-kommunikációs szféra radikális átalakulása) megváltoztatta az emberek mindennapi életét. Miközben sokan mindezt kedvező változásként élik meg, nem vesznek tudomást a kapitalista rendszer és a gyors technikai haladás közötti okozati összefüggésről. A kapitalizmusnak e fontos erényét a mikroökonómia szokványos oktatása sem világítja meg a diákok számára, és nem kap kellő hangsúlyt a vezető politikusok megnyilvánulásaiban sem. _________________ Literature on post-socialist transformation usually deals with the political, economic and social sides of it, although there have also been important changes in the field of technical advance in the last twenty years. One of capitalisms main virtues is the strong incentive it gives to dynamism, enterprise and the innovation process. Every revolutionary new prodŹuct (for civilian use) has been brought about by the capitalist system. The socialist system was capable at most of developing new military products. The article analyses how far this radical difference can be explained by the innate tendencies and basis attributes of the two systems. Our daily lives have been transformed by these new products (for instance, the sphere of information and communications by the computer, the mobile phone and the internet). While many people see all these as favourable changes, fewer discern the causal relation between the capitalist system and rapid technical progress. Yet the usual syllabus of microeconomics does not enlighten students on this important virtue of capitalism, which is not adequately emphasized in the statements of leading politicians either.

Cognitive dissonance and the effect of acceptance of methodology, beliefs about religion, religious orientation, and dogmatism on the success of university students in a religious studies course

The problem investigated was negative effects on the ability of a university student to successfully complete a course in religious studies resulting from conflict between the methodologies and objectives of religious studies and the student's system of beliefs. Using Festinger's theory of cognitive dissonance as a theoretical framework, it was hypothesized that completing a course with a high level of success would be negatively affected by (1) failure to accept the methodologies and objectives of religious studies (methodology), (2) holding beliefs about religion that had potential conflicts with the methodologies and objectives (beliefs), (3) extrinsic religiousness, and (4) dogmatism. The causal comparative method was used. The independent variables were measured with four scales employing Likert-type items. An 8-item scale to measure acceptance of the methodologies and objectives of religious studies and a 16-item scale to measure holding of beliefs about religion having potential conflict with the methodologies were developed for this study. These scales together with a 20-item form of Rokeach's Dogmatism Scale and Feagin's 12-item Religious Orientation Scale to measure extrinsic religiousness were administered to 144 undergraduate students enrolled in randomly selected religious studies courses at Florida International University. Level of success was determined by course grade with the 27% of students receiving the highest grades classified as highly successful and the 27% receiving the lowest grades classified as not highly successful. A stepwise discriminant analysis produced a single significant function with methodology and dogmatism as the discriminants. Methodology was the principal discriminating variable. Beliefs and extrinsic religiousness failed to discriminate significantly. It was concluded that failing to accept the methodologies and objectives of religious studies and being highly dogmatic have significant negative effects on a student's success in a religious studies course. Recommendations were made for teaching to diminish these negative effects.