Evaluación de modelos aplicados a la producción de materia seca de Brachiaria brizantha en el periodo lluvioso

En éste trabajo se compararon modelos no lineales para describir la dinámica de crecimiento de plantas con base en la producción de materia seca en Brachiaria brizantha CV. Toledo a diferentes edades de corte y bajo fertilización nitrogenada en época de lluvias, la cual permitió establecer puntos de equilibrio, estudio de la monotonía y concavidad. Los resultados mostraron que cuatro modelos están relacionados con la constante A concerniente al rendimiento máximo de materia seca. Los puntos de equilibrio se ven afectados por factores vinculados al desarrollo del cultivo. En condiciones de sequía el modelo Gompertz muestra una debilidad frente al resto, por lo que su uso estaría restringido en tales condiciones climatológicas. Los modelos Von Bertalanffy y Brody carecen de un punto de inflexión, por lo que en ensayos donde se presume la presencia de inflexiones en la producción de materia seca, su implementación no es conveniente. Se puede sugerir el uso del modelo logístico en condiciones de sequía, mientras que en períodos lluviosos, el uso de un modelo logístico o Gompertz está sujeto a la realización previa del Análisis de Covarianza. La fertilización nitrogenada, la edad de corte, la tasa intrínseca de crecimiento del pasto B. brizantha, así como los demás factores que afectan el desarrollo de ésta especie determinan la sustentabilidad en la producción de materia seca

Study protocol for a pragmatic randomised controlled trial in general practice investigating the effectiveness of acupuncture against migraine

<p>Abstract</p> <p>Background</p> <p>Migraine is a chronic neurologic disease that can severely affect the patient's quality of life. Although in recent years many randomised studies have been carried out to investigate the effectiveness of acupuncture as a treatment for migraine, it remains a controversial issue. Our aim is to determine whether acupuncture, applied under real conditions of clinical practice in the area of primary healthcare, is more effective than conventional treatment.</p> <p>Methods/Design</p> <p>The design consists of a pragmatic multi-centre, three-armed randomised controlled trial, complemented with an economic evaluation of the results achieved, comparing the effectiveness of verum acupuncture with sham acupuncture, and with a control group receiving normal care only.</p> <p>Patients eligible for inclusion will be those presenting in general practice with migraine and for whom their General Practitioner (GP) is considering referral for acupuncture. Sampling will be by consecutive selection, and by randomised allocation to the three branches of the study, in a centralised way following a 1:1:1 distribution (verum acupuncture; sham acupuncture; conventional treatment). Secondly, one patient in three will be randomly selected from each of the acupuncture (verum or sham) groups for a brain perfusion study (by single photon emission tomography). The treatment with verum acupuncture will consist of 8 treatment sessions, once a week, at points selected individually by the acupuncturist. The sham acupuncture group will receive 8 sessions, one per week, with treatment being applied at non-acupuncture points in the dorsal and lumbar regions, using the minimal puncture technique. The control group will be given conventional treatment, as will the other two groups.</p> <p>Discussion</p> <p>This trial will contribute to available evidence on acupuncture for the treatment of migraine. The primary endpoint is the difference in the number of days with migraine among the three groups, between the baseline period (the 4 weeks prior to the start of treatment) and the period from weeks 9 to 12. As a secondary aspect, we shall record the index of laterality and the percentage of change in the mean count per pixel in each region of interest measured by the brain perfusion tomography, performed on a subsample of the patients within the real and sham acupuncture groups.</p> <p>Trial registration</p> <p>Current Controlled Trials ISRCTN98703707.</p

Effectiveness of acupuncture, special dressings and simple, low-adherence dressings for healing venous leg ulcers in primary healthcare: study protocol for a cluster-randomized open-labeled trial

<p>Abstract</p> <p>Background</p> <p>Venous leg ulcers constitute a chronic recurring complaint that affects 1.0–1.3% of the adult population at some time in life, and which corresponds to approximately 75% of all chronic ulcers of the leg. Multilayer compression bandaging is, at present, the only treatment that has been proved to be effective in treating this type of ulcer. There is no consensus, however, about the dressings that may be applied, beneath the compression, to promote the healing of this type of ulcer, as there does not seem to be any added benefit from using special dressings rather than simple, low-adherence ones. As well as analgesia, acupuncture provokes peripheral vasodilation, in skin and muscles – which has been demonstrated both experimentally and in clinical practice – probably due to the axon reflex, among other mechanisms. The aim of the present study is to measure the effectiveness and cost of compression treatment for venous leg ulcers combined with special dressings, in comparison with low-adherence ones and acupuncture.</p> <p>Methods/design</p> <p>Cluster-randomized open-labeled trial, at 15 primary healthcare clinics in the Sevilla-Sur Healthcare District, with a control group treated with compression bandaging and low-adherence dressings; the experiment will consist, on the one hand, of the compression treatment applied in combination with special dressings (Treatment 1), and on the other, the compression treatment applied in association with low-adherence dressings, together with acupuncture (Treatment 2).</p> <p>Discussion</p> <p>The results will be measured and recorded in terms of the median time elapsed until complete healing of the ulcer, and the rate of complete healing at 3 months after beginning the treatment. An economic analysis will also be made.</p> <p>This study, carried out in the context of real clinical practice, will provide information for decision-taking concerning the effectiveness of special dressings. Moreover, for the first time a high-quality study will evaluate the effectiveness of acupuncture in the process of healing venous leg ulcers.</p> <p>Trial registration</p> <p>Current Controlled Trials ISRCTN26438275.</p

Risk of secondary haematological malignancies in patients with follicular lymphoma:an analysis of 1028 patients treated in the rituximab era

Summary Follicular lymphoma (FL) is the most common indolent lymphoma. Currently there are many comparable treatment options available for FL. When selecting the most optimal therapy it is important to consider possible late effects of the treatment as well as survival. Secondary haematological malignancy (SHM) is a severe late effect of treatments, but the incidence of SHMs is still largely unknown. The goal of the present study was to determine the incidence of SHMs and how therapeutic decisions interfere with this risk. The study included 1028 FL patients with a median follow‐up time of 5·6 years. The 5‐year risk of SHM was 1·1% and the risk was associated with multiple lines of treatment (P = 0·016). The 5‐year risk of SHM was 0·5% after the first‐line treatment and 1·6% after the second‐line. The standardized incidence ratio (SIR) was 6·2 (95% confidence interval 3·4–10·5) for SHM overall. This retrospective study found that the risk of SHM was low after first‐line treatment in FL patients from the rituximab era. However, the risk of SHM increases with multiple lines of treatment. Therapeutic approaches should aim to achieve as long a remission as possible with first‐line treatment, thereby postponing the added risk of SHM

Epidemiological pattern, incidence, and outcomes of COVID-19 in liver transplant patients

In liver transplant patients, chronic immunosuppression increases the risk of acquiring COVID-19 but it could reduce disease severity. Com- plete immunosuppression with- drawal may not be justified. However, mycophenolate withdrawal or tem- porary conversion to calcineurin inhibitors or everolimus until disease resolution could be beneficial in hos- pitalised patients

Predictors of adherence to public health behaviors for fighting COVID-19 derived from longitudinal data

The present paper examines longitudinally how subjective perceptions about COVID-19, one’s community, and the government predict adherence to public health measures to reduce the spread of the virus. Using an international survey (N = 3040), we test how infection risk perception, trust in the governmental response and communications about COVID-19, conspiracy beliefs, social norms on distancing, tightness of culture, and community punishment predict various containment-related attitudes and behavior. Autoregressive analyses indicate that, at the personal level, personal hygiene behavior was predicted by personal infection risk perception. At social level, social distancing behaviors such as abstaining from face-to-face contact were predicted by perceived social norms. Support for behavioral mandates was predicted by confidence in the government and cultural tightness, whereas support for anti-lockdown protests was predicted by (lower) perceived clarity of communication about the virus. Results are discussed in light of policy implications and creating effective interventions

Politicization of COVID-19 health-protective behaviors in the United States: Longitudinal and cross-national evidence

During the initial phase of the COVID-19 pandemic, U.S. conservative politicians and the media downplayed the risk of both contracting COVID-19 and the effectiveness of recommended health behaviors. Health behavior theories suggest perceived vulnerability to a health threat and perceived effectiveness of recommended health-protective behaviors determine motivation to follow recommendations. Accordingly, we predicted that—as a result of politicization of the pandemic—politically conservative Americans would be less likely to enact recommended health-protective behaviors. In two longitudinal studies of U.S. residents, political conservatism was inversely associated with perceived health risk and adoption of health-protective behaviors over time. The effects of political orientation on health-protective behaviors were mediated by perceived risk of infection, perceived severity of infection, and perceived effectiveness of the health-protective behaviors. In a global cross-national analysis, effects were stronger in the U.S. (N = 10,923) than in an international sample (total N = 51,986), highlighting the increased and overt politicization of health behaviors in the U.S