Edinburgi : Apud Balfour et Smellie, 1782.

London : Longmans, Green, 1872.

Edinburgh : Bell & Bradfute, 1807.

London : Caxton Pub. Co, 1908-1909.

Edinburgh : printed for J. Carfrae, 1823.

London : Macmillan, 1896.

London : J. Churchill, 1864.

Paris : J.-B. Baillière, 1905.

2019

Natalia Shenkman.

Source: Brazilian Journal of Probability and Statistics, Volume 34, Number 1, 127--135.

Abstract:
While derivations of the characterization of the $d$-variate exchangeable Marshall–Olkin copula via $d$-monotone sequences relying on basic knowledge in probability theory exist in the literature, they contain a myriad of unnecessary relatively complicated computations. We revisit this issue and provide proofs where all undesired artefacts are removed, thereby exposing the simplicity of the characterization. In particular, we give an insightful analytical derivation of the monotonicity conditions based on the monotonicity properties of the survival probabilities.

Lucas Pereira Lopes, Vicente Garibay Cancho, Francisco Louzada.

Source: Brazilian Journal of Probability and Statistics, Volume 33, Number 4, 801--825.

Abstract:
Multivariate options are adequate tools for multi-asset risk management. The pricing models derived from the pioneer Black and Scholes method under the multivariate case consider that the asset-object prices follow a Brownian geometric motion. However, the construction of such methods imposes some unrealistic constraints on the process of fair option calculation, such as constant volatility over the maturity time and linear correlation between the assets. Therefore, this paper aims to price and analyze the fair price behavior of the call-on-max (bivariate) option considering marginal heteroscedastic models with dependence structure modeled via copulas. Concerning inference, we adopt a Bayesian perspective and computationally intensive methods based on Monte Carlo simulations via Markov Chain (MCMC). A simulation study examines the bias, and the root mean squared errors of the posterior means for the parameters. Real stocks prices of Brazilian banks illustrate the approach. For the proposed method is verified the effects of strike and dependence structure on the fair price of the option. The results show that the prices obtained by our heteroscedastic model approach and copulas differ substantially from the prices obtained by the model derived from Black and Scholes. Empirical results are presented to argue the advantages of our strategy.

We propose a new semiparametric approach for modelling nonlinear univariate diffusions, where the observed process is a nonparametric transformation of an underlying parametric diffusion (UPD). This modelling strategy yields a general class of semiparametric Markov diffusion models with parametric dynamic copulas and nonparametric marginal distributions. We provide primitive conditions for the identification of the UPD parameters together with the unknown transformations from discrete samples. Likelihood-based estimators of both parametric and nonparametric components are developed and we analyze the asymptotic properties of these. Kernel-based drift and diffusion estimators are also proposed and shown to be normally distributed in large samples. A simulation study investigates the finite sample performance of our estimators in the context of modelling US short-term interest rates. We also present a simple application of the proposed method for modelling the CBOE volatility index data.

Peng Shi, Zifeng Zhao.

Source: The Annals of Applied Statistics, Volume 14, Number 1, 357--380.

Abstract:
In actuarial research a task of particular interest and importance is to predict the loss cost for individual risks so that informative decisions are made in various insurance operations such as underwriting, ratemaking and capital management. The loss cost is typically viewed to follow a compound distribution where the summation of the severity variables is stopped by the frequency variable. A challenging issue in modeling such outcomes is to accommodate the potential dependence between the number of claims and the size of each individual claim. In this article we introduce a novel regression framework for compound distributions that uses a copula to accommodate the association between the frequency and the severity variables and, thus, allows for arbitrary dependence between the two components. We further show that the new model is very flexible and is easily modified to account for incomplete data due to censoring or truncation. The flexibility of the proposed model is illustrated using both simulated and real data sets. In the analysis of granular claims data from property insurance, we find substantive negative relationship between the number and the size of insurance claims. In addition, we demonstrate that ignoring the frequency-severity association could lead to biased decision-making in insurance operations.

Yanjun Qian, Jianhua Z. Huang, Chiwoo Park, Yu Ding.

Source: The Annals of Applied Statistics, Volume 13, Number 3, 1537--1563.

Abstract:
In situ transmission electron microscope (TEM) adds a promising instrument to the exploration of the nanoscale world, allowing motion pictures to be taken while nano objects are initiating, crystalizing and morphing into different sizes and shapes. To enable in-process control of nanocrystal production, this technology innovation hinges upon a solution addressing a statistical problem, which is the capability of online tracking a dynamic, time-varying probability distribution reflecting the nanocrystal growth. Because no known parametric density functions can adequately describe the evolving distribution, a nonparametric approach is inevitable. Towards this objective, we propose to incorporate the dynamic evolution of the normalized particle size distribution into a state space model, in which the density function is represented by a linear combination of B-splines and the spline coefficients are treated as states. The closed-form algorithm runs online updates faster than the frame rate of the in situ TEM video, making it suitable for in-process control purpose. Imposing the constraints of curve smoothness and temporal continuity improves the accuracy and robustness while tracking the probability distribution. We test our method on three published TEM videos. For all of them, the proposed method is able to outperform several alternative approaches.

Nadja Klein, Michael Stanley Smith.

Source: Bayesian Analysis, Volume 14, Number 4, 1143--1171.

Abstract:
We show how to extract the implicit copula of a response vector from a Bayesian regularized regression smoother with Gaussian disturbances. The copula can be used to compare smoothers that employ different shrinkage priors and function bases. We illustrate with three popular choices of shrinkage priors—a pairwise prior, the horseshoe prior and a g prior augmented with a point mass as employed for Bayesian variable selection—and both univariate and multivariate function bases. The implicit copulas are high-dimensional, have flexible dependence structures that are far from that of a Gaussian copula, and are unavailable in closed form. However, we show how they can be evaluated by first constructing a Gaussian copula conditional on the regularization parameters, and then integrating over these. Combined with non-parametric margins the regularized smoothers can be used to model the distribution of non-Gaussian univariate responses conditional on the covariates. Efficient Markov chain Monte Carlo schemes for evaluating the copula are given for this case. Using both simulated and real data, we show how such copula smoothing models can improve the quality of resulting function estimates and predictive distributions.

Thomas Staudt, Timo Aspelmeier, Oskar Laitenberger, Claudia Geisler, Alexander Egner, Axel Munk.

Source: Statistical Science, Volume 35, Number 1, 92--111.

Abstract:
Super-resolution microscopy is rapidly gaining importance as an analytical tool in the life sciences. A compelling feature is the ability to label biological units of interest with fluorescent markers in (living) cells and to observe them with considerably higher resolution than conventional microscopy permits. The images obtained this way, however, lack an absolute intensity scale in terms of numbers of fluorophores observed. In this article, we discuss state of the art methods to count such fluorophores and statistical challenges that come along with it. In particular, we suggest a modeling scheme for time series generated by single-marker-switching (SMS) microscopy that makes it possible to quantify the number of markers in a statistically meaningful manner from the raw data. To this end, we model the entire process of photon generation in the fluorophore, their passage through the microscope, detection and photoelectron amplification in the camera, and extraction of time series from the microscopic images. At the heart of these modeling steps is a careful description of the fluorophore dynamics by a novel hidden Markov model that operates on two timescales (HTMM). Besides the fluorophore number, information about the kinetic transition rates of the fluorophore’s internal states is also inferred during estimation. We comment on computational issues that arise when applying our model to simulated or measured fluorescence traces and illustrate our methodology on simulated data.

KM Harris
Aug 1, 1989; 9:2982-2997
Articles

Op-ed by Mr Claudio Borio, Head of the Monetary and Economic Department of the BIS, published in Il Sole 24 Ore, 8 November 2019.

New calculations show that the ring of light surrounding a black hole is actually made up of infinite subrings that can’t be seen with current technology

Biologist Tagide deCarvalho created this award-winning image of the tardigrade using fluorescent stains

The project hasn’t yet been greenlit, but a proposal just got major funding to explore the potential for the lunar observatory

The snazzy search is part of the telescope’s 30th anniversary celebration

Taking mom out for Mother's Day brunch is a tradition for many. But with people staying home and restaurants closed except for delivery or pick-up, this year's Mother's Day will be a little bit different. Food columnist Andrew Coppolino looks at options.

The Canadian Football League is asking the federal government for up to $150 million in financial assistance due to the COVID-19 pandemic.

Join our Facebook live on Thursday at noon with Dr. Roselyn Wilson a psychiatrist at St. Joseph’s Healthcare Hamilton’s Youth Wellness Centre. She'll talk with us about how COVID-19 is heightening anxiety in some young people. We'll talk about how to help the young people in your life through the pandemic.

The post Dousing Fires with Futuristic Helicopters appeared first on SOLIDWORKS Education Blog.

Born: July 9, 1938;

Chronic wet cough is a common symptom well recognized by pediatricians. Protracted bacterial bronchitis is defined as more than 4 weeks of wet cough that responds to antibiotic treatment. Diagnosis of protracted bacterial bronchitis is not readily accepted by pediatricians

Children with chronic wet cough often have bronchitis, which is evident during bronchoscopy. Purulent bronchial secretions suggest the presence of bacterial infection. Children with chronic wet cough frequently have a bacterial infection of the lower airway. (Read the full article)

Adult patients with neurocardiogenic syncope have shown high rates of depression. Patients with more severe depressive symptoms have higher rates of syncope recurrence. Psychiatric interventions improve quality of life and decrease syncope recurrence rates.

Children with neurocargiogenic syncope presented a 2.6-fold higher rate of clinically significant depressive symptoms compared to healthy controls. No recurrent syncope was noted during follow-up which along with improvement in family functioning predicted depressive symptoms improvement. (Read the full article)

Bilateral acute otitis media (AOM) is considered more severe than unilateral AOM, and several guidelines recommend more active management of bilateral AOM. However, severity of symptoms and otoscopic signs of bilateral and unilateral AOM have previously not been comprehensively studied.

Bilateral AOM seems to be clinically only a slightly more severe illness than unilateral AOM. When assessing AOM severity, bilaterality should not be used as a determining criterion; instead, the child’s symptoms together with otoscopic signs should also be acknowledged. (Read the full article)

Preterm infants are born with low serum levels and low body stores of tocopherol. Serum levels ≥0.5 mg/dL are required for protection against lipid peroxidation. Previous studies have shown good intestinal absorption of vitamin E given intragastrically to preterm infants.

Serum α-tocopherol increases after a single 50-IU/kg dose of vitamin E as dl-α-tocopheryl acetate given intragastrically to very preterm infants soon after birth; however, 30% of infants still have serum α-tocopherol level <0.5 mg/dL 24 hours after dosing. (Read the full article)

Available bowel preparation solutions for colonoscopy continue to represent a challenge for children and their families due to poor taste, high volume, and dietary restrictions with subsequent poor compliance and need to place nasogastric tube for administration.

Low-volume polyethylene glycol (PEG) preparations and sodium picosulphate plus magnesium oxide and citric acid (NaPico+MgCit) are noninferior to PEG 4000 with simethicon for bowel preparation before colonoscopy in children. Given its higher tolerability and acceptability profile, NaPico+MgCit should be preferred in children. (Read the full article)

Fathers’ attitude and support affects breastfeeding outcomes. Fathers are currently not targeted in breastfeeding support and care provided by health care professionals. Breastfeeding interventions delivered to fathers have been shown to increase breastfeeding exclusivity and duration.

A coparenting breastfeeding support intervention delivered to mothers and fathers in the postpartum period showed beneficial effects on breastfeeding duration, paternal breastfeeding confidence, breastfeeding help provided by fathers, and mothers’ satisfaction with fathers’ involvement with breastfeeding. (Read the full article)

Treatment of idiopathic steroid-resistant nephrotic syndrome is challenging, and therapeutic options are limited. In spite of good initial response with rituximab, responders always remain prone to further relapse, necessitating either repeat course of rituximab or addition of another steroid-sparing immunosuppressant.

Mycophenolate mofetil may be an effective maintenance therapy to consider as an additive immunosuppressant after induction with rituximab in maintaining remission among children with refractory steroid-resistant nephrotic syndrome. (Read the full article)

Stevens-Johnson syndrome (SJS) is a rare and severe immunologic phenomenon characterized by rash and mucous membrane disease. SJS may be triggered by medications and, less commonly, by infections such as Mycoplasma pneumoniae (Mp). Outbreaks of SJS are exceedingly rare.

We describe the largest SJS outbreak reported in children, which was also Mp-associated. In the first case-control study of this disease, we identify predictors of Mp-associated SJS versus non–Mp-associated SJS, including fewer skin lesions, pneumonia, and elevated erythrocyte sedimentation rate. (Read the full article)

Endotracheal intubation is a mandatory skill for neonatal trainees. It is a difficult skill to acquire, and success rates of junior doctors are low and falling.

Videolaryngoscopy allows the supervisor to share the intubator’s view of the airway and provide more informed guidance. Teaching intubation using a videolaryngoscope with the screen visible to the instructor results in significantly higher success rates for inexperienced doctors. (Read the full article)

François Hollande semble hésiter à se rendre à Kinshasa en octobre pour le sommet de la francophonie. Il serait bien inspiré de ne pas offrir au président, Joseph Kabila, une telle occasion de s’afficher réconcilié avec les démocraties après les élections présidentielle et législative calamiteuses en République démocratique du Congo (RDC) qui privent le régime d’une véritable légitimité démocratique. En se rendant à Kinshasa, François Hollande enverrait un message plus que trouble aux pays d’Afrique où la démocratisation est encore une lutte quotidienne que l’on paie au prix du sang.

Objectives: Antibiotic combination therapy is used for severe infections caused by multidrug-resistant (MDR) Gram-negative bacteria. Yet, data of which combinations are most effective is lacking. This study aimed to evaluate the in vitro efficacy of polymyxin B in combination with 13 other antibiotics against four clinical strains of MDR Pseudomonas aeruginosa.

Methods: We evaluated the interactions of polymyxin B in combination with amikacin, aztreonam, cefepime, chloramphenicol, ciprofloxacin, fosfomycin, meropenem, minocycline, rifampicin, temocillin, thiamphenicol or trimethoprim by automated time-lapse microscopy using predefined cut-off values indicating inhibition of growth (≤10⁶ CFU/mL) at 24 h. Promising combinations were subsequently evaluated in static time-kill experiments.

Results: All strains were intermediate or resistant to polymyxin B, anti-pseudomonal β-lactams, ciprofloxacin and amikacin. Genes encoding β-lactamases (e.g., bla_PAO and bla_OXA-50) and mutations associated with permeability and efflux were detected in all strains. In the time-lapse microscopy experiments, positive interactions were found with 39 of 52 antibiotic combination/bacterial strain setups. Enhanced activity was found against all four strains with polymyxin B used in combination with aztreonam, cefepime, fosfomycin, minocycline, thiamphenicol and trimethoprim. Time kill experiments showed additive or synergistic activity with 27 of the 39 tested polymyxin B combinations, most frequently with aztreonam, cefepime, and meropenem.

Conclusion: Positive interactions were frequently found with the tested combinations, also against strains that harboured several resistance mechanisms to the single drugs and with antibiotics that are normally not active against P. aeruginosa. Further study is needed to explore the clinical utility of these combinations.

Antibiotic resistance is a global concern; however, data on antibiotic-resistant Ureaplasma spp. and Mycoplasma hominis are limited in comparison to similar data on other microbes. A total of 492 Ureaplasma spp. and 13 M. hominis strains obtained in Hangzhou, China, in 2018, were subjected to antimicrobial susceptibility testing for levofloxacin, moxifloxacin, erythromycin, clindamycin, and doxycycline using the broth microdilution method. The mechanisms underlying quinolone and macrolide resistance were determined. Meanwhile, a model of the topoisomerase IV complex bound to levofloxacin in wild-type Ureaplasma spp. was built to study the quinolone resistance mutations. For Ureaplasma spp., the levofloxacin, moxifloxacin and erythromycin resistance rates were 84.69%, 51.44% and 3.59% in U. parvum and 82.43%, 62.16% and 5.40% in U. urealyticum, respectively. Of the 13 M. hominis strains, 11 were resistant to both levofloxacin and moxifloxacin, and five strains showed clindamycin resistance. ParC S83L was the most prevalent mutation in levofloxacin-resistant Ureaplasma strains, followed by ParE R448K. The two mutations GyrA S153L and ParC S91I were commonly identified in quinolone-resistant M. hominis. A molecular dynamics-refined structure revealed that quinolone resistance-associated mutations inhibited the interaction and reduced affinity with gyrase or topoisomerase IV and quinolones. The novel mutations S21A in the L4 protein and G2654T and T2245C in 23S rRNA and ermB gene were identified in erythromycin-resistant Ureaplasma spp. Fluoroquinolone resistance in Ureaplasma spp. and Mycoplasma hominis remains high in China, the rational use of antibiotics needs to be further enhanced.

Introduction: This study was performed to evaluate the impacts of vanA-positivity of Enterococcus faecium (EFM) exhibiting diverse susceptibility phenotypes to glycopeptides on clinical outcomes in patients with a bloodstream infection (BSI) through a prospective, multicenter, observational study.

Methods: A total of 509 patients with an EFM BSI from eight sentinel hospitals in South Korea during a two-year period were enrolled in this study. Risk factors of the hosts and causative EFM isolates were assessed to determine associations with the 30-day mortality of EFM BSI patients via multivariable logistic regression analyses.

Results: The vanA gene was detected in 35.2% (179/509) of EFM isolates; 131 EFM isolates exhibited typical VanA phenotypes (group vanA-VanA), while the remaining 48 EFM isolates exhibited atypical phenotypes (group vanA-Atypical), including VanD (n = 43) and vancomycin-variable phenotypes (n = 5). A multivariable logistic regression indicated that vanA-positivity of causative pathogens was independently associated with the increased 30-day mortality rate in the patients with an EFM BSI; however, there was no significant difference in the survival rates between the patients of the vanA-VanA and vanA-Atypical groups (log-rank test, P = 0.904).

Conclusions: A high 30-day mortality rate was observed in patients with vanA-positive EFM BSIs, and vanA-positivity of causative EFM was an independent risk factor for early mortality irrespective of the susceptibility phenotypes to glycopeptides; thus, intensified antimicrobial stewardship is needed to improve clinical outcome of patients with vanA-positive EFM BSI.

Effective immediately and for the foreseeable future, the Entrepreneurship and Assistance Clinic is expanding its scope and service offerings to small Pennsylvania businesses, in response to the COVID-19 pandemic.