629 research outputs found

    Peyronie's disease - a perspective on the disease and the long-term results of radiotherapy

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    From 1966 to 1988, 98 of 108 patients with symptomatic Peyronie's disease received radiotherapy at our institution. In 11 of 61 patients (18%) who attended the clinic regularly for follow-up for longer than a year, new lesions distinct from the original lesions developed. This confirms that there is progression of the disease in a substantial number of cases after treatment. Long-term follow-up over an average of 111,5 months was achieved by means of a questionnaire in 47 of the 98 cases (48%). Forty-one of these patients (87,2%) had sexual intercourse after radiation. Twenty-eight of the 41 (68,3%) still have intercourse. Their average age at present is 59,6 years while the average age of the 13 patients (31,7%) not having intercourse is 70,9 years. The decline in sexual activity is thus age-related. Twenty-one of 25 patients (84%) experienced relief from pain, and angulation of the penis improved in 17 of 44 patients (38,6%) after radiotherapy. Radiotherapy may therefore be of benefit to patients with active Peyronie's disease and should be investigated in a randoIIlised controlled study

    Solitary waves and supersonic reaction front in metastable solids

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    Motivated by an increasing number of remarkable experimental observations on the role of pressure and shear stress in solid reactions, explosions and detonations, we present a simple toy model that embodies nonlinear elasticity and dispersion as well as chemical or phase transformation. This generalization of the Toda Lattice provides an effective model for the description of the organization during an abrupt transformation in a solid. One of the challenges is to capture both the equilibrium degrees of freedom as well as to quantify the possible role of out-of-equilibrium perturbations. In the Toda Lattice, we verify that the particle velocities converge in distribution towards the Maxwell-Boltzmann distribution, thus allowing us to define a bona-fide temperature. In addition, the balance between nonlinearity and wave dispersion may create solitary waves that act as energy traps. In the presence of reactive chemistry, we show that the trapping of the released chemical energy in solitary waves that are excited by an initial perturbation provides a positive feedback that enhances the reaction rate and leads to supersonic explosion front propagation. These modes of rupture observed in our model may provide a first-order description of ultrafast reactions of heterogeneous mixtures under mechanical loading

    Factors influencing the distribution of Cactoblastis cactorum, a biological control agent of Opuntia stricta in Kruger National Park, South Africa

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    Cactoblastis cactorum, a phycitid moth, has been used with considerable success as a biological control agent against several different cactus species in many parts of the world, including Opuntia stricta in Kruger National Park [KNP], South Africa. Although the moth has become widespread and abundant in KNP, its populations have not reached levels where it is able to provide the desired level of control on the alien species which has invaded more than 35 000 ha of the park and continues to spread. Although several factors, especially acquired predators and parasitoids, are known to curb the abundance of C. cactorum in South Africa, the extent to which this applies in KNP is unknown. Logistic regression and Canonical Community Analysis were used to determine the biotic and abiotic factors affecting the distribution and abundance of C. cactorum in KNP. To do this, maps of the ranges of the insect and host plant were constructed and integrated with other environmental features. The logistic regression showed that O. stricta density had no influence on whether or not C. cactorum was present in an area. The Canonical Community Analysis suggested that a high fire frequency, the herbicide control programme and the presence of small host plants may be important in limiting the distribution of C. cactorum, either directly or indirectly, through impacts on associated predators or parasitoids

    Environmental factors influencing the distribution of Opuntia stricta, an invasive alien plant in the Kruger National Park, South Africa

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    Opuntia stricta (Cactaceae), an alien weed, has invaded an area of more than 35 000 ha in the Skukuza region of the Kruger National Park [KNP]. The distribution of the plant and features of the environment were used to identify biotic and abiotic factors which may be affecting the distribution and density of the plant. A Canonical Community Analysis revealed that none of the environmental factors that were monitored influenced the distribution or abundance of O. stricta in KNP. There were no apparent natural barriers that might limit the occurrence of O. stricta within the KNP. The study provides insight into the relationship between the invader and host environment, showing that there is a high probability that, unless there is appropriate intervention, O. stricta will eventually colonise the entire KNP

    Experimental and theoretical study of vibrations of a cantilevered beam using a ZnO piezoelectric sensor

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    Piezoelectric sensors can measure vibrations of solid structures very accurately. A model of a cantilevered beam, with a ZnO film on one side is presented. Both viscous and internal damping are considered. The output of the sensor is modeled and matched with experimental results by adjusting the damping parameters. A theoretical formulation for damage is introduced. Experimental results for a damaged beam confirm the shift in frequencies to lower values. The model is used to identify the extent of the damage

    Changes in J-SOAP-II and SAVRY Scores Over the Course of Residential, Cognitive-Behavioral Treatment for Adolescent Sexual Offending

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    Although the Juvenile Sex Offender Assessment Protocol-II (J-SOAP-II) and the Structured Assessment of Violence Risk in Youth (SAVRY) include an emphasis on dynamic, or modifiable factors, there has been little research on dynamic changes on these tools. To help address this gap, we compared admission and discharge scores of 163 adolescents who attended a residential, cognitive-behavioral treatment program for sexual offending. Based on reliable change indices, one-half of youth showed a reliable decrease on the J-SOAP-II Dynamic Risk Total Score and one-third of youth showed a reliable decrease on the SAVRY Dynamic Risk Total Score. Contrary to expectations, decreases in risk factors and increases in protective factors did not predict reduced sexual, violent nonsexual, or any reoffending. In addition, no associations were found between scores on the Psychopathy Checklist: Youth Version and levels of change. Overall, the J-SOAP-II and the SAVRY hold promise in measuring change, but further research is needed

    Risk and Protective Factors for Recidivism Among Juveniles Who Have Offended Sexually

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    Literature on risk factors for recidivism among juveniles who have sexually offended (JSOs) is limited. In addition, there have been no studies published concerning protective factors among this population. The purpose of this study was to examine the relationship of risk and protective factors to sexual and nonsexual recidivism among a sample of 193 male JSOs (mean age = 15.26). Youths were followed for an average of 7.24 years following discharge from a residential sex offender treatment program. The risk factor opportunities to reoffend, as coded based on the Estimate of Risk of Adolescent Sexual Offense Recidivism, was associated with sexual recidivism. Several risk factors (e.g., prior offending; peer delinquency) were associated with nonsexual recidivism. No protective factors examined were associated with sexual recidivism, although strong attachments and bonds as measured by the Structured Assessment of Violence Risk in Youth was negatively related to nonsexual recidivism. These findings indicate that risk factors for nonsexual recidivism may be consistent across both general adolescent offender populations and JSOs, but that there may be distinct protective factors that apply to sexual recidivism among JSOs. Results also indicate important needs for further research on risk factors, protective factors, and risk management strategies for JSOs

    Sacroiliac tuberculosis masquerading as mechanical lower back pain in a collegiate basketball athlete: a case presentation

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    Background: Sacroiliac tuberculosis is a rare condition for which early diagnosis and effective management frequently proves challenging. This report describes a case that was initially overlooked due to its presentation and unreported constitutional symptoms.Aim: To alert clinicians about skeletal tuberculosis, an often neglected diagnostic differential, which requires a high index of clinical suspicion, especially for patients from endemic areas.Findings: This patient’s presentation (sports injury) and unreported constitutional symptoms resulted in a delay in the diagnosis and initial institution of treatment.Implications: This report illustrates the importance of specifically asking about constitutional symptoms, even in sports injury settings and being mindful of infectious diseases or other chronic medical conditions, which may masquerade as common sports injuries.Keywords: skeletal tuberculosis, sacroiliitis, hip pai

    "The difference that makes a difference": highlighting the role of variable contexts within an HIV Prevention Community Randomised Trial (HPTN 071/PopART) in 21 study communities in Zambia and South Africa.

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    This paper explores contextual heterogeneity within a community randomised trial HPTN 071 (Population Effects of Antiretroviral Treatment to Reduce HIV Transmission) carried out in 21 study communities (12 Zambian, 9 South African). The trial evaluates the impact of a combination HIV prevention package (including household-based HIV counselling and testing and anti-retroviral treatment (ART) eligibility regardless of CD4-count) on HIV incidence. The selection, matching and randomisation of study communities relied on key epidemiological and demographic variables and community and stakeholder support. In 2013, following the selection of study communities, a "Broad Brush Survey" (BBS) approach was used to rapidly gather qualitative data on each study community, prior to the implementation of the trial intervention. First-year process indicator intervention data (2014-2015) were collected during the household-based intervention by community lay workers. Using an open/closed typology of urban communities (indicating more or less heterogeneity), this qualitative inquiry presents key features of 12 Zambian communities using a list of four meta-indicators (physical features, social organisation, networks and community narratives). These indicators are then compared with four intervention process indicators in a smaller set of four study communities. The process indicators selected for this analysis indicate response to the intervention (uptake) amongst adults. The BBS qualitative data are used to interpret patterns of similarity and variability in the process indicators across four communities. We found that meta-indicators of local context helped to interpret patterns of similarity and variability emerging across and within the four communities. Features especially significant for influencing heterogeneity in process indicators include proportion of middle-class residents, proximity to neighbouring communities and town centre, the scale of the informal economy, livelihood-linked mobility, presence of HIV stakeholders over time and commitment to community action. Future interdisciplinary analysis is needed to explore if these patterns of difference continue to hold up over the full intervention period and all intervention communities
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