On Estimating the Size and Confidence of a Statistical Audit

We consider the problem of statistical sampling for auditing elections, and we develop a remarkably simple and easily-calculated upper bound for the sample size necessary for determining with probability at least c whether a given set of n objects contains b or more “bad” objects. While the size of the optimal sample drawn without replacement can be determined with a computer program, our goal is to derive a highly accurate and simple formula that can be used by election officials equipped with only a simple calculator

Conversion in laparoscopic cholecystectomy for acute cholecystitis

Scopul lucrării. Colecistectomia laparoscopică a devenit o operație curentă în practica chirurgicală zilnică și este considerată în prezent un standard de aur, oferind posibilitatea de a rezolva aproape toate litiazele veziculare simptomatice. În anumite cazuri totuși, condițiile tehnice particulare creează riscuri specifice, ce impun conversia la tehnica deschisă.Materiale și metodă. Studiul nostru se întinde pe o perioada de 5 ani, fiind incluși următorii factori: forma anatomopatologică, motivele și rata conversiei, complicațiile postoperatorii și durata medie de spitalizare.Rezultate. În perioada decembrie 2018- decembrie 2022 au fost efectuate 3576 de colecistectomii laparoscopice din care 2848 au fost realizate pentru colecistita acută (79,6%). Din punct de vedere al formelor anatomopatologice au predominat colecistitele acute catarale (52%), urmate de cele flegmonoase (37%) și gangrenoase (11%). Rata conversiei a fost de 5,4% (156 cazuri), cu o tendință constantă la descreștere corelată cu îmbunătățirea experienței echipei chirurgicale. Printre cele mai întâlnite cauze ce au dus la conversie putem enumera: anatomie incertă datorită proceselor inflamatorii importante (62 de pacienți), fibroza la nivelul triunghiului Calot (43 de cazuri), dar și alte cauze (hemoragie, ciroză hepatică, sindrom aderențial – 51 de cazuri ). La pacienții la care s-a realizat conversia, complicațiile postoperatorii au fost întâlnite în 18% din cazuri, durata medie de spitalizare a fost de 13 zile, cu o mortalitate de 1,28%.Concluzii. Conversia în colecistectomia laparoscopică pentru colecistita acută reprezintă o dovadă a maturității chirurgicale şi nu trebuie considerată un eșec al tehnicii laparoscopice, fiind salutată în situații în care avantajul abordului laparoscopic este depăsit de riscurile unor situații întâlnite în practică.Aim of study. Laparoscopic cholecystectomy is now the “gold standard” operation for patients with gallstones disease. However, a number of patients require conversion to open cholecystectomy for the safe completion of the procedure, generally being certified that untransparency in operative field, unclear anatomical proportion , are the most frequent causes of conversion and postoperative complications.Materials and methods. From 3576 patients who underwent laparoscopic cholecystectomy between 2018-2022, we selected a lot of 2848 cases of acute cholecystitis and evaluated the conversion rate encountered. The patients were selected according to the morphopatological form of cholecystitis as: catarrhal cholecystitis – 52% (1436 cases), phlegmonous cholecystitis - 37% (1275 cases) and gangrenous cholecystitis – 11% (896 cases). The conversion rate was 5,4% (156 cases) Results. In this paper the modalities, the technical particularities and the causes that can lead to conversion in laparoscopic cholecystectomy for acute cholecystitis are discussed.Conclusions. Laparoscopic cholecystectomies can be safely performed for almost all patients with acute cholecystitis by an experienced surgical team, although unclear anatomy secondary to inflammation remains the most common reason for conversion leading to higher rate of postoperative complications and a longer hospital stay, the overall impact of acute cholecystitis on the operative outcome has decreased with time

Repeated PTZ Treatment at 25-Day Intervals Leads to a Highly Efficient Accumulation of Doublecortin in the Dorsal Hippocampus of Rats

BACKGROUND: Neurogenesis persists throughout life in the adult mammalian brain. Because neurogenesis can only be assessed in postmortem tissue, its functional significance remains undetermined, and identifying an in vivo correlate of neurogenesis has become an important goal. By studying pentylenetetrazole-induced brain stimulation in a rat model of kindling we accidentally discovered that 25±1 days periodic stimulation of Sprague-Dawley rats led to a highly efficient increase in seizure susceptibility. METHODOLOGY/PRINCIPAL FINDINGS: By EEG, RT-PCR, western blotting and immunohistochemistry, we show that repeated convulsive seizures with a periodicity of 25±1 days led to an enrichment of newly generated neurons, that were BrdU-positive in the dentate gyrus at day 25±1 post-seizure. At the same time, there was a massive increase in the number of neurons expressing the migratory marker, doublecortin, at the boundary between the granule cell layer and the polymorphic layer in the dorsal hippocampus. Some of these migrating neurons were also positive for NeuN, a marker for adult neurons. CONCLUSION/SIGNIFICANCE: Our results suggest that the increased susceptibility to seizure at day 25±1 post-treatment is coincident with a critical time required for newborn neurons to differentiate and integrate into the existing hippocampal network, and outlines the importance of the dorsal hippocampus for seizure-related neurogenesis. This model can be used as an in vivo correlate of neurogenesis to study basic questions related to neurogenesis and to the neurogenic mechanisms that contribute to the development of epilepsy

On auditing elections when precincts have different sizes

We address the problem of auditing an election when precincts may have different sizes. Prior work in this field has emphasized the simpler case when all precincts have the same size. Using auditing methods developed for use with equal-sized precincts can, however, be inefficient or result in a loss of statistical confidence when applied in to elections with variablesized precincts. We survey, evaluate, and compare a variety of approaches to the variable-sized precinct auditing problem, including the safe method [11] based on theory developed for equal-sized precincts. We introduce new methods such as the negative-exponential method (negexp) that select precincts independently for auditing with predetermined probabilities, and the “ppebwr ” method that uses a sequence of rounds to select precincts with replacement according to some predetermined probability distribution that may depend on error bounds for each precinct (hence the name ppebwr: probability proportional to error bounds, with replacement), where the error bounds may depend on the sizes of the precincts, or on how the votes were cast in each precinct. We give experimental results showing that negexp and ppebwr can dramatically reduce (by a factor or two or three) the cost of auditing compared to methods such as safe that depend on the use of uniform sampling. Sampling so that larger precincts are audited with appropriately larger probability can yield large reductions in expected number of votes counted in an audit. We also examine the optimal auditing strategy, which is nicely representable as a linear programming problem but only really computable for small elections (fewer than a dozen precincts). We conclude with some recommendations for practice.

Increased Degradation Rates in the Components of the Mitochondrial Oxidative Phosphorylation Chain in the Cerebellum of Old Mice

Brain structures differ in the magnitude of age-related neuron loss with the cerebellum being more affected. An underlying cause could be an age-related decline in mitochondrial bioenergetics. Successful aging of mitochondria reflects a balanced turnover of proteins involved in mitochondrial biogenesis and mitophagy. Thus, an imbalance in mitochondrial turnover can contribute to the diminution of cellular function seen during aging. Mitochondrial biogenesis and mitophagy are mediated by a set of proteins including MFN1, MFN2, OPA1, DRP1, FIS1 as well as DMN1l and DNM1, all of which are required for mitochondrial fission. Using N15 labeling, we report that the turnover rates for DMN1l and FIS1 go in opposite directions in the cerebellum of 22-month-old C57BL6j mice as compared to 3-month-old mice. Previous studies have reported decreased turnover rates for the mitochondrial respiratory complexes of aged rodents. In contrast, we found increased turnover rates for mitochondrial proteins of the oxidative phosphorylation chain in the aged mice as compared to young mice. Furthermore, the turnover rate of the components that are most affected by aging –complex III components (ubiquinol cytochrome C oxidoreductase) and complex IV components (cytochrome C oxidase)– was significantly increased in the senescent cerebellum. However, the turnover rates of proteins involved in mitophagy (i.e., the proteasomal and lysosomal degradation of damaged mitochondria) were not significantly altered with age. Overall, our results suggest that an age-related imbalance in the turnover rates of proteins involved in mitochondrial biogenesis and mitophagy (DMN1l, FIS1) in conjunction with an age-related imbalance in the turnover rates of proteins of the complexes III and IV of the electron transfer chain, might impair cerebellar mitochondrial bioenergetics in old mice

Muvi: Automatically inferring multi-variable access correlations and detecting related semantic and concurrency bugs

Software defects significantly reduce system dependability. Among various types of software bugs, semantic and concurrency bugs are two of the most difficult to detect. This paper proposes a novel method, called MUVI, that detects an important class of semantic and concurrency bugs. MUVI automatically infers commonly existing multi-variable access correlations through code analysis and then detects two types of related bugs: (1) inconsistent updates—correlated variables are not updated in a consistent way, and (2) multivariable concurrency bugs—correlated accesses are not protected in the same atomic sections in concurrent programs. We evaluate MUVI on four large applications: Linux, Mozilla, MySQL, and PostgreSQL. MUVI automatically infers more than 6000 variable access correlations with high accuracy (83%). Based on the inferred correlations, MUVI detects 39 new inconsistent update semantic bugs from the latest versions of these applications, with 17 of them recently confirmed by the developers based on our reports. We also implemented MUVI multi-variable extensions to two representative data race bug detection methods (lockset and happens-before). Our evaluation on five real-world multi-variable concurrency bugs from Mozilla and MySQL shows that the MUVI-extension correctly identifies the root causes of four out of the five multi-variable concurrency bugs with 14 % additional overhead on average. Interestingly, MUVI also helps detect four new multi-variable concurrency bugs in Mozilla that have never been reported before. None of the nine bugs can be identified correctly by the original race detectors without our MUVI extensions