instruction:
In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
question:
Context: It is common in public health and epidemiology that the outcome of interest is counts of events occurrence. Analysing these data using classical linear models is mostly inappropriate, even after transformation of outcome variables due to overdispersion. Zero-adjusted mixture count models such as zero-inflated and hurdle count models are applied to count data when over-dispersion and excess zeros exist. Main objective of the current paper is to apply such models to analyse risk factors associated with human helminths (S. haematobium) particularly in a case where there's a high proportion of zero counts.", 'The data were collected during a community-based randomised control trial assessing the impact of mass drug administration (MDA) with praziquantel in Malawi, and a school-based cross sectional epidemiology survey in Zambia. Count data models including traditional (Poisson and negative binomial) models, zero modified models (zero inflated Poisson and zero inflated negative binomial) and hurdle models (Poisson logit hurdle and negative binomial logit hurdle) were fitted and compared.', 'Using Akaike information criteria (AIC), the negative binomial logit hurdle (NBLH) and zero inflated negative binomial (ZINB) showed best performance in both datasets. With regards to zero count capturing, these models performed better than other models.\Question: Do zero adjusted models with applications to analysing helminths count data?
answer:
This paper showed that zero modified NBLH and ZINB models are more appropriate methods for the analysis of data with excess zeros. The choice between the hurdle and zero-inflated models should be based on the aim and endpoints of the study.

question:
Context: The aim of this study was the analysis of total, early and late complications following venous access port implantation between 1998 and 2008 at the Department of Surgery of the University of Rostock, Germany. A comparison between different implantation techniques addressing success rate, complication rate and duration of operation was performed. These results were further analysed in regard to the level of training of the participating surgeons.', 'A retrospective analysis of 1423 venous access port implantations between 1998 and 2008 was performed.', "The rate of total complications was 13.8%. Among 4.7% early complications pneumothorax was the most common. The rate of late complications was 9.1%. Most common were infection (4.9%) followed by dysfunction of the catheter (3.5%). 1322 venous access port implantations were performed using puncture of the subclavian vein and Seldinger's technique. 101 operations were performed by direct access through dissection of the cephalic vein and open introduction of the catheter. Operation time in the open group was significantly longer than in the puncture group (46.5min vs. 38.7min, p=0.005). There were significantly more late complications (9.6% vs. 2%, p=0.01) and total complications (14.5% vs. 4%, p=0.005) in the puncture group vs. the open access group. Primary success rates of open access vs. puncture were 100% and 96.8%, respectively. The rate of complications was independent of the experience status of the surgeon. However, the rate of total and late complications significantly decreases with number of performed operations.\Question: Is [ Venous Access Port Implantation an Ideal Teaching Operation - An Analysis of 1423 Cases ]?
answer:
Venous port implantation is a relatively simple procedure despite its possible complications. An open access technique is safer than puncture. The rate of complications significantly decreases with increasing number of performed operations. Therefore venous port implantation and especially the open access method is an ideal teaching operation in a structured surgical training programme.

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Context: The aim of this study was to review the impact of salvage external beam radiotherapy (EBRT) of postprostatectomy patients with long-term follow-up on biochemical-free recurrence (BFR) and metastatic-free survival, and to describe pathological and clinical predictors of outcome.', 'In the period 1987-2010, 76 postprostatectomy patients with biochemical and clinical recurrence received salvage EBRT. Patients were treated with conformal EBRT and 68 (90%) received a dose of 70 Gy; eight patients (10%) received a dose of 60-64 Gy. No patients received adjuvant or neoadjuvant androgen deprivation therapy in conjunction with salvage EBRT.', 'The median follow-up time after salvage EBRT was 82 months (range 5-192 months). Seventeen patients (22%) developed biochemical recurrence subsequent to postprostatectomy salvage EBRT during the observation time, and the overall 50 and 75 month actuarial BFR rates after salvage EBRT were 84% and 79%, respectively. Seven patients (9%) developed metastatic disease and two patients died of prostate cancer. Independent predictors of biochemical recurrence were seminal vesicle invasion (SVI) in the prostatectomy specimen (p < 0.05) and prostate-specific antigen doubling time (PSADT) of 6 months or less (p = 0.041) before salvage EBRT.\Question: Is prostate-specific antigen doubling time subsequent to radical prostatectomy a predictor of outcome following salvage external beam radiation therapy : a single-centre experience?
answer:
Salvage EBRT provides effective long-term BFR and metastatic-free survival in a selected group of patients with detectable, rising prostate-specific antigen values following radical prostatectomy. SVI and PSADT are prognostic variables for a non-durable response to salvage EBRT and thus predictors of high-risk prostate cancer in patients in whom neoadjuvant and adjuvant androgen deprivation therapy should be considered.