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The von Mises distribution, which is also known as the Circular Normal distribution is a well-studied and commonly used distribution for analyzing data on a unit circle. It has many properties and similarities to the normal distribution defined on the real line, making it popular for modeling circular data. Since it is unimodal, finite mixtures of von Mises distributions may be used to deal with circular data that may potentially have more than one mode. In this paper, our goal is to cluster such data sets after approximating each data set as a finite mixture of von Mises distributions. To accomplish such clustering we need a distance measure between any two such finite mixtures. For this, we propose using the Kullback-Liebler and Bhattacharyya distance measures. The applicability and usefulness of the proposed measures in identifying clusters present in a data set is first demonstrated through a simulation study. A real-life application that clusters the surface wind direction data in five major Indian cities is then studied using the proposed measures. [ABSTRACT FROM AUTHOR]

Background: Repair of thoracic aortic aneurysms with either endovascular repair (TEVAR) or open surgical repair (OSR) represents major surgery, is costly and associated with significant complications. The aim of this study was to establish accurate costs of delivering TEVAR and OSR in a cohort of UK NHS patients suitable for open and endovascular treatment for the whole treatment pathway from admission and to discharge and 12-month follow-up. Methods: A prospective study of UK NHS patients from 30 NHS vascular/cardiothoracic units in England aged ≥18, with distal arch/descending thoracic aortic aneurysms (CTAA) was undertaken. A multicentre prospective cost analysis of patients (recruited March 2014–July 2018, follow-up until July 2019) undergoing TEVAR or OSR was performed. Patients deemed suitable for open or endovascular repair were included in this study. A micro-costing approach was adopted. Results: Some 115 patients having undergone TEVAR and 35 patients with OSR were identified. The mean (s.d.) cost of a TEVAR procedure was higher £26 536 (£9877) versus OSR £17 239 (£8043). Postoperative costs until discharge were lower for TEVAR £7484 (£7848) versus OSR £28 636 (£23 083). Therefore, total NHS costs from admission to discharge were lower for TEVAR £34 020 (£14 301), versus OSR £45 875 (£43 023). However, mean NHS costs for 12 months following the procedure were slightly higher for the TEVAR £5206 (£11 585) versus OSR £5039 (£11 994). Conclusions: Surgical procedure costs were higher for TEVAR due to device costs. Total in-hospital costs were higher for OSR due to longer hospital and critical care stay. Follow-up costs over 12 months were slightly higher for TEVAR due to hospital readmissions. Detailed micro-costing of endovascular stent grafting (TEVAR) and open surgical repair (OSR) in a cohort of UK NHS patients for whole of treatment pathway up to 12 months follow-up. Overall costs are higher for OSR, driven by length of stay and critical care post-procedure, compared to TEVAR, with costs driven by stent graft devices. These detailed micro-costing estimates exceed current NHS tariffs for reimbursement. [ABSTRACT FROM AUTHOR]

We generated Optical Coherence Tomography (OCT) data of much higher resolution than usual on retinal nerve fiber layer (RNFL) thickness of a given eye. These consist of measurements made at hundreds of angular-points defined on a circular coordinate system. Traditional analysis of OCT RNFL data does not utilize insightful characteristics such as its circularity and granularity for common downstream applications. To address this, we present a new circular statistical framework that defines an Angular Decay function and thereby provides a directionally precise representation of an eye with attention to patterns of focused RNFL loss. By applying to a clinical cohort of Asian Indian eyes, the generated circular data were modeled with a finite mixture of von Mises distributions, which led to an unsupervised identification in different age-groups of recurrent clusters of glaucomatous eyes with distinct directional signatures of RNFL decay. New indices of global and local RNFL loss were computed for comparing the structural differences between these glaucoma clusters across the age-groups and improving classification. Further, we built a catalog of directionally precise statistical distributions of RNFL thickness for the said population of normal eyes as stratified by their age and optic disc size. [ABSTRACT FROM AUTHOR]

Mango fruits majorly suffers from anthracnose and fruit fly infestations during storage, transportation and marketing. Hot water treatments (HWTs) at specific levels have shown to control the incidence of these important threats. Application of HWT not only act as a quarantine measure, but also maintains the quality and enhance the marketability of fruits, even at room temperature (RT), leading to its vast applicability in local / international markets. In this study, post harvest application of HWTs (48°C for 60 min and 55°C for 10 min) in mango cv. Banganapalli recorded reduced ethylene production rate, physiological loss in weight, improved sugar content, ascorbic acid, total carotenoids, phenolics and antioxidants compared to control. Combination of HWTs (48°C for 60 min followed by 55°C for 10 min) resulted in degradation of some quality parameters compared to individual HWT and control. [ABSTRACT FROM AUTHOR]

In this paper, real-time speech signals with a sampling rate of 1 kHz are continuously acquired with the help of a 3.5mm microphone and an external data acquisition board - DAQ. An uniform white Gaussian noise signal with a noise level of 5dB was added to the background noise, and this portion was processed using short time Fourier transformations with a frequency bin of 512 and time-frequency sampling information component of one for hanning window to get separate frames. Then it passes through the Chebyshev filter, where the filter behaviour varies, depending on which window in the filter section we prefer. Finally, the filtered output is fed into the discrete wavelet transformations for Daubechies additional 2D picture analysis. This similarity check determines how similar the multi is resolved. The proposed model is tested for various noise levels of uniform white Gaussian noise type in LabVIEW 2019 version along with DAQ board. [ABSTRACT FROM AUTHOR]

An effective synthetic approach has been demonstrated for the construction of diverse bicyclic fused cyclopentenones from Morita–Baylis–Hillman (MBH) carbonates of propiolaldehydes. The present transformation was initiated through the propargylation of an alkenylamine with an MBH carbonate followed by the Pauson–Khand reaction of the product methyl 3-(alkenylamino)-2-methylenealk-4-ynoate. This facile method provides diverse scaffolds of cyclopentenone fused with aza -cycles having additional functionality in good yields. [ABSTRACT FROM AUTHOR]

Increased resistance to a large number of antibacterial drugs poses a serious challenge in chemotheraphy of infectious diseases. Here, we have made and attempt to redesign the existing chemotherapeutic agent enrofloxacin (EN) to treat resistant bacteria. Precisely, we synthezied EN conjugated zinc oxide nanoparticles (EN-ZNP) and explored enhancing the antibacterial activity of enrofloxacin. Zinc oxide nanoparticles (ZNP) were synthesized by microwave irradiation and amine functionalization by co-condensation with APTES and then by utilizing EPC/NHS chemistry, enrofoxacin was conjugated. Conjugation and their stability were confirmed by FT-IR spectra and Zeta potential. EN fraction in EN-ZNP was determined indirectly using UV-Vis spectroscopy. The MIC values obtained for EN-ZNP against MTCC cultures and clinical isolates of Escherichia coli, Salmonella typhimurium, Staphylococcus aureus were significantly (P <0.05) lower than ZNP and, when compared to native EN it is significantly higher. However, the concentration of conjugated EN in EN-ZNP was significantly lower than the MIC of native EN. The results suggest that enrofloxacin can be successfully conjugated with amine functionalized zinc oxide nanoparticles. The antibacterial efficacy was significantly improved when ZNP conjugated with EN against standard MTCC cultures and clinical isolates. [ABSTRACT FROM AUTHOR]

Generation mean analysis study in bitter gourd was undertaken using six basic generations viz. P1, P2, F1, F2, B1 and B2 population were developed from gynoecious (IIHRBTGy- 491) × monoecious (IIHR Sel -19 -1 and IIHR Sel-78-4) crosses. The gynoecious parent was superior for node for first female flowering, number of fruits and yield/plant whereas the monoecious parents were superior for fruit length, fruit diameter and fruit weight. F1 showed superior performance over mid parent for number of fruits, fruit length, fruit weight and yield per plant. F2 plants were significantly diverse. B1 and B2 population exhibited mean value closer to their recurrent parents. Significance of one or more scaling tests, i.e. A, B, C and D in most of the traits revealed the presence of epistasis in both the crosses except for node bearing 1st male flower. Days to 1st female flower opening, node bearing 1st female flower, fruit diameter and yield showed presence of duplicate epistasis whereas days to 1st male flower opening, number of fruits per plant, fruit length and fruit weight showed complimentary epistasis in IIHRBTGy - 491 × IIHR Sel -19 -1 cross. Node bearing 1st female flower, fruit length, fruit diameter and yield showed presence of duplicate epistasis whereas days to 1st female flower opening, days to 1st male flower opening, number of fruits and fruit weight showed complimentary epistasis in IIHRBTGy - 491× IIHR Sel-78-4 cross. Additive gene action may be predominant for inheritance of node bearing 1st male flower. [ABSTRACT FROM AUTHOR]

Progressive optic neuropathies such as glaucoma are major causes of blindness globally. Multiple sources of subjectivity and analytical challenges are often encountered by clinicians in the process of early diagnosis and clinical management of these diseases. In glaucoma, the structural damage is often characterized by neuroretinal rim (NRR) thinning of the optic nerve head, and other clinical parameters. Baseline structural heterogeneity in the eyes can play a key role in the progression of optic neuropathies, and present challenges to clinical decision-making. We generated a dataset of Optical Coherence Tomography (OCT) based high-resolution circular measurements on NRR phenotypes, along with other clinical covariates, of 3973 healthy eyes as part of an established clinical cohort of Asian Indian participants. We introduced CIFU, a new computational pipeline for CIrcular FUnctional data modeling and analysis. We demonstrated CIFU by unsupervised circular functional clustering of the OCT NRR data, followed by meta-clustering to characterize the clusters using clinical covariates, and presented a circular visualization of the results. Upon stratification by age, we identified a healthy NRR phenotype cluster in the age group 40–49 years with predictive potential for glaucoma. Our dataset also addresses the disparity of representation of this particular population in normative OCT databases. [ABSTRACT FROM AUTHOR]

The depletion of high-grade ores has forced the utilization of low-grade ores. The small liberation sizes in the low-grade ores require fine grinding which is an energy intensive operation. In the present study, low-grade chromite ore bearing platinum group of elements (PGE) was used as an experimental material. The previous study concluded the liberation size of around 1–50 µm for chromite ore bearing PGE minerals. Therefore, the target product size for grinding was kept below 50 µm. The wet fine grinding experiments were performed in a vertical stirred mill. Four significant operating variables stirrer speed, grinding time, feed size, and solids concentration were investigated for their effect on the performance of stirred mills. The performance of the mill was assessed in terms of achieving small product size at lower energy consumption. The detailed investigations were carried out according to popularly adopted methods of statistical design of experiment. The results revealed that stirrer speed, grinding time, and feed size played crucial role on the performance of stirred mill. Mathematical correlations were developed for predicting product size and energy consumption. The models developed were then optimized using quadratic programing to minimize the combination of product size and energy consumption. [ABSTRACT FROM AUTHOR]

A nonparametric test labelled 'Rao Spacing-frequencies test' is explored and developed for testing whether two circular samples come from the same population. Its exact distribution and performance relative to comparable tests such as the Wheeler-Watson test and the Dixon test in small samples, are discussed. Although this test statistic is shown to be asymptotically normal, as one would expect, this large sample distribution does not provide satisfactory approximations for small to moderate samples. Exact critical values for small samples are obtained and tables provided here, using combinatorial techniques, and asymptotic critical regions are assessed against these. For moderate sample sizes in-between i.e. when the samples are too large making combinatorial techniques computationally prohibitive but yet asymptotic regions do not provide a good approximation, we provide a simple Monte Carlo procedure that gives very accurate critical values. As is well-known, the large number of usual rank-based tests are not applicable in the context of circular data since the values of such ranks depend on the arbitrary choice of origin and the sense of rotation used (clockwise or anti-clockwise). Tests that are invariant under the group of rotations, depend on the data through the so-called 'spacing frequencies', the frequencies of one sample that fall in between the spacings (or gaps) made by the other. The Wheeler-Watson, Dixon, and the proposed Rao tests are of this form and are explicitly useful for circular data, but they also have the added advantage of being valid and useful for comparing any two samples on the real line. Our study and simulations establish the 'Rao spacing-frequencies test' as a desirable, and indeed preferable test in a wide variety of contexts for comparing two circular samples, and as a viable competitor even for data on the real line. Computational help for implementing any of these tests, is made available online "TwoCircles" R package and is part of this paper. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the personality traits of agricultural scientists and to find out their relationship with well-being attributes and to predict their happiness and life satisfaction. Data was collected from 622 respondents (424 males, 198 females; mean age 41.8 ± 6.3 years) by administering Big-Five Inventory (BFI-10), Oxford Happiness Questionnaire (OHQ), Satisfaction with Life Scale (SWLS), and Psychological Well-Being (PWB-18) questionnaires. Findings revealed significant gender differences in neuroticism and openness, favouring female scientists. Such gender differences were not observed in their scores on happiness, life satisfaction, and PWB. Most of the scientists reported higher levels of happiness (86.2% moderately to very happy), life satisfaction (68.9% satisfied to extremely satisfied), and PWB (57.4%). With age, extraversion, agreeableness, and conscientiousness increased, whereas neuroticism and openness decreased. Similarly, environmental mastery, positive relations, and total PWB improved with age. Except for neuroticism, personality traits were positively correlated with happiness, life satisfaction, and PWB. The regression model on happiness captured 63.7% of variation by considering personality traits (neuroticism being the strongest contributor) and traits of PWB (self-acceptance and environmental mastery being the largest contributors). In the model for life satisfaction, neuroticism, among the personality traits, self-acceptance, environmental mastery, positive relations, and purpose in life, among the PWB, captured 35.3% of the variation in life satisfaction. The implications of these findings in relation to the workplace environment are discussed. [ABSTRACT FROM AUTHOR]

In this paper, we perform multivariate time series analysis from a Bayesian machine learning perspective through the proposed multivariate Bayesian time series (MBTS) model. The multivariate structure and the Bayesian framework allow the model to take advantage of the association structure among target series, select important features, and train the data-driven model at the same time. Extensive analyses on both simulated data and empirical data indicate that the MBTS model is able to, cover the true values of regression coefficients in 90% credible intervals, select the most important predictors, and boost the prediction accuracy with higher correlation in absolute value of the target series, and consistently yield superior performance over the univariate Bayesian structural time series (BSTS) model, the autoregressive integrated moving average with regression (ARIMAX) model, and the multivariate ARIMAX (MARIMAX) model, in one-step-ahead forecast and ten-steps-ahead forecast. [ABSTRACT FROM AUTHOR]

A concept of atmospheric turbulence characterization using laser light backscattered off a moving unresolved target or a moving target with a glint is considered and analyzed through wave-optics numerical simulations. The technique is based on analysis of the autocorrelation function and variance of the power signal measured by the target-in-the-loop atmospheric sensing (TILAS) system composed of a single-mode-fiber-based optical transceiver and the moving target. It is shown that the TILAS received power signal autocorrelation function strongly depends on the turbulence distribution and is weakly sensitive to the turbulence strength, while the signal variance equally depends on these parameters. Assuming the atmospheric turbulence model can be represented by a single spatially localized turbulence layer and the target position and speed are known independently, consecutive analysis of the autocorrelation function and variance of the TILAS signal allows evaluation of both the turbulence layer strength and position along the optical propagation path. It is also demonstrated that the autocorrelation function can potentially be used for the atmospheric turbulence outer scale estimation. [ABSTRACT FROM AUTHOR]

In this paper, we consider general classes of estimators based on higher-order sample spacings, called the Generalized Spacings Estimators. Such classes of estimators are obtained by minimizing the Csiszár divergence between the empirical and true distributions for various convex functions, include the "maximum spacing estimators" as well as the maximum likelihood estimators (MLEs) as special cases, and are especially useful when the latter do not exist. These results generalize several earlier studies on spacings-based estimation, by utilizing non-overlapping spacings that are of an order which increases with the sample size. These estimators are shown to be consistent as well as asymptotically normal under a fairly general set of regularity conditions. When the step size and the number of spacings grow with the sample size, an asymptotically efficient class of estimators, called the "Minimum Power Divergence Estimators," are shown to exist. Simulation studies give further support to the performance of these asymptotically efficient estimators in finite samples and compare well relative to the MLEs. Unlike the MLEs, some of these estimators are also shown to be quite robust under heavy contamination. [ABSTRACT FROM AUTHOR]

Background: Being a successful peer-led team learning (PLTL) workshop leader involves developing content knowledge and workshop facilitation skills. These skills connected to being a peer leader, however, do not terminate at the end of one's undergraduate program. In fact, many former peer leaders denote having been a peer leader on their LinkedIn profile. This study examines the transferable skills that former peer leaders identified as being valuable in their current positions. We conducted semi-structured interviews with former peer leaders from varying disciplines, universities, ages, and years since being a peer leader. Results: Interview questions captured leadership experiences including successes and challenges of being peer leaders, roles and responsibilities, and specific transferable skills further developed by being peer leaders and how they are being utilized in the leaders' current position. Conclusion: Thematic analyses of these interviews indicate that former peer leaders recognize leadership skills, coping with many challenges (including not having the right answer), collaboration/teamwork skills, self-confidence, and problem-solving skills as being relevant and frequently used in their current work. [ABSTRACT FROM AUTHOR]

This paper summarizes a talk given by the author at the Indian Academy of Sciences, Bengaluru on December 12, 2019. It outlines the multiplicity of situations where measurements on directions in two, three, or more dimensions are observed, and form the basis for answering various scientific questions. After briefly outlining the novelty in dealing with such data and the need for an entirely different set of analytical tools, one of the basic questions that arises before any further inference viz. testing isotropy of circular data, is addressed. The author was initiated into this topic of directional statistics by Professor C R Rao during the 1960s and is pertinent to this occasion celebrating him. [ABSTRACT FROM AUTHOR]

Emotional intelligence (EI) is known to contribute for the success of individual or group, and plays an important role in organizational effectiveness through positive behavior. The purpose of the study was to find out the relationship between EI and different components of organization effectiveness viz., teamwork effectiveness, conflict-handling modes and leadership competencies of the scientific personnel in National Agricultural Research and Education System (NARES) in India. The data was collected from 234 respondents by administering EI Test (EIT), Teamwork Skill Questionnaire, Thomas-Kilmann Conflict Mode Instrument (TKI Test) and Leadership Effectiveness Profile. The results indicated that 93.2% of the participants recorded an average level of EI; whereas, only 6.8% have a high level of EI. Majority of participants (78.6%) recorded lower levels of teamwork effectiveness as against 19.2 and 2.2% having average and high levels of team work effectiveness, respectively. Among the conflict-handling modes, avoiding (37.2%), compromising (20.5%) and accommodating (20.1%) are the dominant modes employed by the participants. Among the leadership competencies, people enablement, directional clarity, driving persistence and change orchestration are the dominant reported competencies. EI is significantly and positively correlated with teamwork effectiveness and all the attributes of leadership effectiveness. Among the domains of EI, self-awareness, motivating oneself and handling relationships are significantly related to the teamwork effectiveness and leadership competencies. The findings of the study revealed the importance of EI in contributing the overall success of the organization through building up the teamwork effectiveness and contributing to the leadership competencies. The implication of the study includes the role of EI as important criteria in selection and recruitment and a competency to be trained in employee's in-service capacity building programs in order to improve the overall organizational effectiveness. [ABSTRACT FROM AUTHOR]

This paper considers the problem of estimating the autoregressive parameter in discretely observed Ornstein–Uhlenbeck processes. Two consistent estimators are proposed: one obtained by maximizing a kernel-based likelihood function, and another by minimizing a Kolmogorov-type distance from independence. After establishing the consistency of these estimators, their finite-sample performance and possible normality in large samples, is investigated by means of extensive simulations. An illustrative example to credit rating is discussed. [ABSTRACT FROM AUTHOR]

The plant Calotropis procera (Aiton) Dryand belong to the Apocynaceae family it is popularly known as "Rui" in Marathi, " Mudar" in hindi other common name include Rubber Bush, Apple of sodom. (India & Pakistan). The bark and leaves are known to show wound healing, shows anti-Hyperglycemic effect, Analgesic, Anti pyretic, neuromuscular blocking activity, Purgative, anti-cancer activities. The phytochemistry of plant reveals presence of triterpenoids, flavonoids, cardiac glycosides, cardenolides, anthocyanins, a-amyrin, β-amyrin, lupeol, β-sitosterol, flavanols, mudarine, resins, a powerful bacteriolytic enzyme calactin, a nontoxic proteolytic enzyme calotropin, and a wax was isolated from the heartwood of Calotropis procera. The present review focuses on pharmacological activities of Calotropis procera. [ABSTRACT FROM AUTHOR]

We present optimal algorithms for sorting on parallel CREW and EREW versions of the pointer machine model. Intuitively, one can view our methods as being based on a parallel mergesort using linked lists rather than arrays (the usual parallel data structure). We also show how to exploit the “locality” of our approach to solve the set expression evaluation problem, a problem with applications to database querying and logic-programming in O(log n) time using O(n) processors. Interestingly, this is an asymptotic improvement over what seems possible using previous techniques. [ABSTRACT FROM AUTHOR]

Current control strategies for soil-transmitted helminths (STH) emphasize morbidity control through mass drug administration (MDA) targeting preschool- and school-age children, women of childbearing age and adults in certain high-risk occupations such as agricultural laborers or miners. This strategy is effective at reducing morbidity in those treated but, without massive economic development, it is unlikely it will interrupt transmission. MDA will therefore need to continue indefinitely to maintain benefit. Mathematical models suggest that transmission interruption may be achievable through MDA alone, provided that all age groups are targeted with high coverage. The DeWorm3 Project will test the feasibility of interrupting STH transmission using biannual MDA targeting all age groups. Study sites (population ≥80,000) have been identified in Benin, Malawi and India. Each site will be divided into 40 clusters, to be randomized 1:1 to three years of twice-annual community-wide MDA or standard-of-care MDA, typically annual school-based deworming. Community-wide MDA will be delivered door-to-door, while standard-of-care MDA will be delivered according to national guidelines. The primary outcome is transmission interruption of the STH species present at each site, defined as weighted cluster-level prevalence ≤2% by quantitative polymerase chain reaction (qPCR), 24 months after the final round of MDA. Secondary outcomes include the endline prevalence of STH, overall and by species, and the endline prevalence of STH among children under five as an indicator of incident infections. Secondary analyses will identify cluster-level factors associated with transmission interruption. Prevalence will be assessed using qPCR of stool samples collected from a random sample of cluster residents at baseline, six months after the final round of MDA and 24 months post-MDA. A smaller number of individuals in each cluster will be followed with annual sampling to monitor trends in prevalence and reinfection throughout the trial. Trial registration: ClinicalTrials.gov [ABSTRACT FROM AUTHOR]

We consider the problem of estimating the lifetime distributions of survival times subject to a general censoring scheme called “middle censoring”. The lifetimes are assumed to follow a parametric family of distributions, such as the Gamma or Weibull distributions, and is applied to cases when the lifetimes come with covariates affecting them. For any individual in the sample, there is an independent, random, censoring interval. We will observe the actual lifetime if the lifetime falls outside of this censoring interval, otherwise we only observe the interval of censoring. This censoring mechanism, which includes both right- and left-censoring, has been called “middle censoring” (see Jammalamadaka and Mangalam, 2003). Maximum-likelihood estimation of the parameters as well as their large-sample properties are studied under this censoring scheme, including the case when covariates are available. We conclude with an application to a dataset from Environmental Economics dealing with ContingentValuation of natural resources. [ABSTRACT FROM AUTHOR]

The Present study reports important secondary metabolites present in Ficus racemosa The Ficus racemosa belong to the family Moraceae, it is popularly known as Glomerata, Cluster fig tree as well as ‘Udumbara’ in Marathi. Various plant parts such as bark, root, leaf, fruits are used as astringent, carminative, anti-dysentery, diabetes, leucoderma, antiasthmatic, hepatoprotective, antioxidant. The powdered Bark was subjected for extraction by using ethanol. These extract were evaluated for detection of various secondary metabolites, like Steroids, Glycosides, tannins, Terpenoids, Alkaloids, Flavonoids. This work evaluated the stem bark of this plant for its Phytochemical and Antiasthmatic activity. [ABSTRACT FROM AUTHOR]

Purpose: To report 2 cases of type IIIb endoleak with the Endurant stent-graft and postulate the cause for the events.Case Report: A type IIIb endoleak was diagnosed at open conversion for a ruptured aneurysm 4 years after implantation of an Endurant stent-graft. In the other case, the endoleak was diagnosed at angiography 4 years after the Endurant stent-graft was implanted; the stent-graft was relined. In both cases the fabric hole was in the body of the stent-graft at the level of the top of the contralateral limb.Conclusion: The cause of the type IIIb endoleaks in these cases was fabric erosion likely due to interaction between the bare metal at the top of the contralateral limb and the fabric of the stent-graft body. [ABSTRACT FROM AUTHOR]

Purpose: To report a systematic literature review of late rupture of abdominal aortic aneurysm (AAA) after endovascular aneurysm repair (EVAR) and the results of a pooled analysis of causes, treatment, and outcomes. Methods: Electronic information sources and bibliographic reference lists were interrogated using a combination of free text and controlled vocabulary searches; 11 articles were ultimately identified that fulfilled the inclusion criteria. The articles reported a total of 190 patients who were included in the qualitative and quantitative synthesis. Mortality within 30 days or during the admission with aneurysm rupture was a primary endpoint; major perioperative morbidity was a secondary endpoint. A meta-analysis was performed for 30-day/in-hospital mortality using the random effects model. Results: A total of 152 ruptures occurred after 16,974 EVAR procedures reported by 8 of the case series, giving an incidence of 0.9% [95% confidence interval (CI) 0.77 to 1.05]. The mean time to rupture was 37 months. Twenty-nine percent (95% CI 20 to 39) of the patients had at least one previous secondary endovascular intervention following the initial EVAR, and 37% (95% CI 30 to 45) were not compliant with surveillance. Type I and III endoleaks were the predominant causes of rupture. Open surgical treatment was undertaken in 61% (95% CI 53 to 68) of the patients who underwent treatment. The pooled estimate for perioperative mortality was 32% (95% CI 24 to 41). A significantly lower mortality was found with endovascular treatment than open surgical management (p=0.027). Conclusion: Graft-related endoleaks appear to be the predominant causes of late aneurysm rupture. Quality of and compliance with post-EVAR surveillance are important factors in late rupture; a large proportion of late ruptures are amenable to endovascular treatment. [ABSTRACT FROM AUTHOR]

‘Middle censoring’ is a very general censoring scheme where the actual value of an observation in the data becomes unobservable if it falls inside a random interval (L, R) and includes both left and right censoring. In this paper, we consider discrete lifetime data that follow a geometric distribution that is subject to middle censoring. Two major innovations in this paper, compared to the earlier work of Davarzani and Parsian [3], include (i) an extension and generalization to the case where covariates are present along with the data and (ii) an alternate approach and proofs which exploit the simple relationship between the geometric and the exponential distributions, so that the theory is more in line with the work of Iyeret al.[6]. It is also demonstrated that this kind of discretization of life times gives results that are close to the original data involving exponential life times. Maximum likelihood estimation of the parameters is studied for this middle-censoring scheme with covariates and their large sample distributions discussed. Simulation results indicate how well the proposed estimation methods work and an illustrative example using time-to-pregnancy data from Baird and Wilcox [1] is included. [ABSTRACT FROM AUTHOR]