The addition of tert-butyl hydro­peroxide (tBuOOH) to two MnII complexes, differing by a small synthetic alteration from an ethyl to a propyl linker in the ligand scaffold, results in the formation of the high-valent bis-oxo complexes, {[MnIV{N4(6-Me-DPEN)}]2(μ-O)2}2+ (1) and {[MnIV{N4(6-Me-DPPN)}]2(μ-O)2}2+ (2).

Features of azimuthal plots for RHEED and its new counterpart, RHEPD, are discussed. The plots, for both electrons and positrons, are determined using dynamical diffraction theory.

Cancer-causing chemicals that occur naturally in foods are far more numerous in the human diet than synthetic carcinogens, yet both types are consumed at levels so low that they currently appear to pose little threat to human health, a committee of the National Research Council said in a report released today.

Researchers have developed an online tool to help water managers find effective ways of tackling eutrophication, an excess growth of weeds and algae that suffocates life in rivers, lakes and seas. They describe the tool as quick and easy to use and understand. Users can compare the likely effects of different strategies for cutting nutrient pollution in surface waters via an interactive map-based system; this is currently available for Sweden and Europe as a whole.

Competitive and fast are two terms that are applicable to the world of computers. Constantly changing and evolving computer systems bring many advantages to the users and techies alike. The race for supremacy between the yet to be launched Vista (scheduled for 2006) and Mac OSX Tiger began in 2003 with Microsoft's announcements of plans for an integrated desktop search functionality in Windows Vista.

Between the planner and journal trend, the rise of mixed media, and growing interest in painting itself, there’s more and more interest in travel watercolor sets. They are an affordable way to invest in a basic set of watercolors for someone who is still learning to paint, as well as a great for taking along […]

Spurred by the insurance regulator to come up with Covid-specific products, several such plans have flooded the market in the past month or so from players such as Star Health & Allied Insurance, Bharti AXA Health Insurance, etc.

Old-growth forests provide unique habitat features and landscape functions compared to younger stands. The goals of many forest management plans in the Pacific Northwest include increasing the area of late-successional and old-growth forests.

Over the past decade, wood-energy use in Alaska has grown dramatically.

The galaxy far far away has items both big and small. The Star Wars Size Comparison Video created by MetaBallStudios brings droids, people and planets together from the Star Wars movies (episode I to VIII, Rogue One and Solo). See how your favorites size up against each other.

Comparison of many things from the Star Wars movies. Only movies from episode I to VIII, Rogue One and Solo. Obviously not everything appears, only the most representative.

Providing scale and context to your audience is one of the key tenets of data visualization, and this video does a fantastic job of giving you the context of the size of everything in the Star Wars universe.

Found on Gizmodo.com.

Several nonlinear model reduction techniques are compared for the three cases of the non-parallel version of the Kuramoto-Sivashinsky equation, the transient regime of flow past a cylinder at $Re=100$ and fully developed flow past a cylinder at the same Reynolds number. The linear terms of the governing equations are reduced by Galerkin projection onto a POD basis of the flow state, while the reduced nonlinear convection terms are obtained either by a Galerkin projection onto the same state basis, by a Galerkin projection onto a POD basis representing the nonlinearities or by applying the Discrete Empirical Interpolation Method (DEIM) to a POD basis of the nonlinearities. The quality of the reduced order models is assessed as to their stability, accuracy and robustness, and appropriate quantitative measures are introduced and compared. In particular, the properties of the reduced linear terms are compared to those of the full-scale terms, and the structure of the nonlinear quadratic terms is analyzed as to the conservation of kinetic energy. It is shown that all three reduction techniques provide excellent and similar results for the cases of the Kuramoto-Sivashinsky equation and the limit-cycle cylinder flow. For the case of the transient regime of flow past a cylinder, only the pure Galerkin techniques are successful, while the DEIM technique produces reduced-order models that diverge in finite time.

A computer-readable, non-transitory medium storing a character string comparison program is provided. The program causes, when executed by a computer, the computer to perform a process including splitting a first character string and a second character string into words; acquiring information including a semantic attribute that represents a semantic nature of each of the words and a conceptual code that semantically identifies said each of the words, from a storage device; identifying a pair of the words having a common semantic attribute between the first character string and the second character string; comparing the conceptual codes of the specified pair of the words between the first character string and the second character string; and generating a comparison result between the first character string and the second character string based upon a comparison result of the conceptual codes.

NEWS 8 IS YOUR LOCAL ELECTION HEADQUARTERS…. AND TONIGHT…VOODOO ECONOMICS! CHIEF POLITICAL CORRESPONDENT MARK DAVIS TELLING US HOW REPEALING THE STATE INCOME TAX IS THE LATEST HEATED TOPIC BETWEEN THE CANIDATES FOR GOVERNOR.   DEMOCRAT NED LAMONT IS OPENING A … Continue reading →

We already know far more about this virus than scientists ever knew during the Spanish flu epidemic

We're comparing the number of Americans to have died from COVID-19 to war casualties. Why not consider AIDS?

A second-generation surivivor whose grandparents died in the Holocaust blasts a newspaper publisher for comparing coronavirus restrictions to Nazi Germany.

William M. Old
Oct 1, 2005; 4:1487-1502
Research

Purpose: ⁶⁸Ga-DOTA-JR11 is an antagonist for somatostatin receptor used in neuroendocrine imaging. The purpose of this study is to compare ⁶⁸Ga-DOTA-JR11 and ⁶⁸Ga-DOTATATE PET/CT in patients with metastatic, well-differentiated neuroendocrine tumors. Methods: Patients with histologically-proven, metastatic and/or unresectable, well-differentiated neuroendocrine tumors were prospectively recruited in this study. They received an intravenous injection of ⁶⁸Ga-DOTATATE (4.0 ± 1.3 mCi) on the first day and ⁶⁸Ga-DOTA-JR11 (4.0 ± 1.4 mCi) on the second day. Whole-body PET/CT scans were performed at 40 to 60 minutes after injection on the same scanner. Physiologic uptake of normal organs, lesion numbers, and lesion uptake were compared. Results: Twenty-nine patients were prospectively enrolled in the study. The SUV_max of the spleen, renal cortex, adrenal glands, pituitary glands, stomach wall, normal liver parenchyma, small intestine, pancreas, and bone marrow were significantly lower on ⁶⁸Ga-DOTA-JR11 than on ⁶⁸Ga-DOTATATE PET/CT (P<0.001). ⁶⁸Ga-DOTA-JR11 detected significantly more liver lesions (539 vs. 356, P = 0.002), but fewer bone lesions (156 vs. 374, P = 0.031, Figure 3) than ⁶⁸Ga-DOTATATE. The tumor-to-background ratio of liver lesions was significantly higher on ⁶⁸Ga-DOTA-JR11 (7.6 ± 5.1 vs. 3.4 ± 2.0, P<0.001). ⁶⁸Ga-DOTA-JR11 and ⁶⁸Ga-DOTATATE PET/CT showed comparable results for primary tumors and lymph node metastases based on either patient-based or lesion-based comparison. Conclusion: ⁶⁸Ga-DOTA-JR11 performs better in the detection ability and TBR of liver metastases. However, ⁶⁸Ga-DOTATATE outperforms ⁶⁸Ga-DOTA-JR11 in the detection of bone metastases. The differential affinity of different metastatic sites provides key information for patient selection in imaging and peptide receptor radionuclide therapy.

Due to their peculiar mechanism of action, the evaluation of radiological response to immune checkpoint inhibitors (ICI) presents many challenges in solid tumors. We aimed to compare the evaluation of first response to Nivolumab by means of CT-based criteria with respect to fluorodeoxyglucose positron emission tomography (FDG-PET) response criteria in non-small-cell lung cancer (NSCLC) patients. Methods: 72 patients with advanced NSCLC were recruited in a mono-institutional ancillary trial within the expanded access program (EAP; NCT02475382) for Nivolumab. Patients underwent CT scan and FDG-PET at baseline and after 4 cycles (first evaluation). In case of progressive disease (PD), an additional evaluation was performed after two further cycles in order to confirm progression. We evaluated the response to treatment with CT scan by means of response evaluation criteria in solid tumors (RECIST) 1.1 and Immuno-related Response Criteria (IrRC) and with FDG-PET by means of PERCIST and immunotherapy-modified-PERCIST (imPERCIST) criteria. The concordance between CT- and PET-based criteria and the capability of each method to predict overall survival (OS) were evaluated. Results: 48/72 patients were evaluable for first response assessment with both PET- and CT-based criteria. We observed low concordance between CT- and PET-based criteria (Kappa value of 0.346 and 0.355 and Kappa value of 0.128 and 0.198 between PERCIST and imPERCIST versus RECIST and irRC respectively). Looking at OS, IrRC were more reliable to distinguish responders from non-responders. However thanks to the prognostic value of partial metabolic response assessed by both PERCIST and Immuno-PERCIST, PET-based response maintained prognostic significant in patients classified as progressive disease on the basis of irRC. Conclusion: Even though the present study did not support the routine use of FDG-PET in the general population of NSCLC patients treated with ICI, it suggests the added prognostic value of the metabolic response assessment, potentially improving the therapeutic decision-making.

Prediction of post-operative pulmonary function in lung cancer patients before tumor resection is essential for patient selection for surgery and is conventionally done with a non-imaging segment counting method (SC) or a two-dimensional planar lung perfusion scintigraphy (PS). The purpose of this study was to compare quantitative analysis of PS to single photon emission computed tomography/computed tomography (SPECT/CT) and to estimate the accuracy of SC, PS and SPECT/CT in predicting post-operative pulmonary function in patients undergoing lobectomy. Methods: Seventy-five non-small cell lung cancer (NSCLC) patients planned for lobectomy were prospectively enrolled (68% males, average age 68.1±8 years ). All patients completed pre-operative forced expiratory volume capacity (FEV1), diffusing capacity of the lung for carbon monoxide (DLCO), Tc99m-MAA lung perfusion scintigraphy with PS and SPECT/CT quantification. A subgroup of 60 patients underwent video-assisted thoracoscopic (VATS) lobectomy and measurement of post-operative FEV1 and DLCO. Relative uptake of the lung lobes estimated by PS and SPECT/CT were compared. Predicted post-operative FEV1 and DLCO were derived from SC, PS and SPECT/CT. Prediction results were compared between the different methods and the true post-operative measurements in patients who underwent lobectomy. Results: Relative uptake measurements differed significantly between PS and SPECT/CT in right lung lobes, with a mean difference of -8.2±3.8, 18.0±5.0 and -11.5±6.1 for right upper, middle and lower lobes respectively (p<0.001). The differences between the methods in the left lung lobes were minor with a mean difference of -0.4±4.4 (p>0.05) and -2.0±4.0 (p<0.001) for left upper and lower lobes respectively. No significant difference and strong correlation (R=0.6-0.76, p<0.001) were found between predicted post-operative lung function values according to SC, PS, SPECT/CT and the actual post-operative FEV1 and DLCO. Conclusion: Although lobar quantification parameters differed significantly between PS and SPECT/CT, no significant differences were found between the predicted post-operative lung function results derived from these methods and the actual post-operative results. The additional time and effort of SPECT/CT quantification may not have an added value in patient selection for surgery. SPECT/CT may be advantageous in patients planned for right lobectomies but further research is warranted.

Head motion degrades image quality and causes erroneous parameter estimates in tracer kinetic modeling in brain PET studies. Existing motion correction methods include frame-based image-registration (FIR) and correction using real-time hardware-based motion tracking (HMT) information. However, FIR cannot correct for motion within one predefined scan period while HMT is not readily available in the clinic since it typically requires attaching a tracking device to the patient. In this study, we propose a motion correction framework with a data-driven algorithm, i.e., using the PET raw data itself, to address these limitations. Methods: We propose a data-driven algorithm, Centroid of Distribution (COD), to detect head motion. In COD, the central coordinates of the line of response (LOR) of all events are averaged over 1-sec intervals to generate a COD trace. A point-to-point change in the COD trace in one direction that exceeded a user-defined threshold was defined as a time point of head motion, which was followed by manually adding additional motion time points. All the frames defined by such time points were reconstructed without attenuation correction and rigidly registered to a reference frame. The resulting transformation matrices were then used to perform the final motion compensated reconstruction. We applied the new COD framework to 23 human dynamic datasets, all containing large head motions, with ¹⁸F-FDG (N = 13) and ¹¹C-UCB-J (N = 10), and compared its performance with FIR and with HMT using the Vicra, which can be considered as the "gold standard". Results: The COD method yielded 1.0±3.2% (mean ± standard deviation across all subjects and 12 grey matter regions) SUV difference for ¹⁸F-FDG (3.7±5.4% for ¹¹C-UCB-J) compared to HMT while no motion correction (NMC) and FIR yielded -15.7±12.2% (-20.5±15.8%) and -4.7±6.9% (-6.2±11.0%), respectively. For ¹⁸F-FDG dynamic studies, COD yielded differences of 3.6±10.9% in Ki value as compared to HMT, while NMC and FIR yielded -18.0±39.2% and -2.6±19.8%, respectively. For ¹¹C-UCB-J, COD yielded 3.7±5.2% differences in VT compared to HMT, while NMC and FIR yielded -20.0±12.5% and -5.3±9.4%, respectively. Conclusion: The proposed COD-based data-driven motion correction method outperformed FIR and achieved comparable or even better performance as compared to the Vicra HMT method in both static and dynamic studies.

The value of interim ¹⁸F-fluorodeoxyglucose positron emission tomography (iPET) guided treatment decisions in patients with diffuse large B-cell lymphoma (DLBCL) has been the subject of much debate. This investigation focuses on a comparison of the Deauville score and the deltaSUV_max (SUV_max) approach – two methods to assess early metabolic response to standard chemotherapy in DLBCL. Methods: Of 609 DLBCL patients participating in the Positron Emission Tomography-guided Therapy of Aggressive non-Hodgkin Lymphomas (PETAL) trial, iPET scans of 596 patients originally evaluated using the SUV_max method were available for post-hoc assessment of the Deauville score. A commonly used definition of an unfavorable iPET result according to the Deauville score is an uptake greater than that of the liver, whereas an unfavorable iPET scan with regard to the SUV_max approach is characterized as a relative reduction of the maximum standardized uptake value between baseline and iPET staging of less than or equal to 66%. We investigated the two methods’ correlation and concordance by Spearman’s rank correlation coefficient and the agreement in classification, respectively. We further used Kaplan-Meier curves and Cox regression to assess differences in survival between patient subgroups defined by the pre-specified cut-offs. Time-dependent receiver operating curve analysis provided information on the methods’ respective discrimination performance. Results: Deauville score and SUV_max approach differed in their iPET-based prognosis. The SUV_max approach outperformed the Deauville score in terms of discrimination performance – most likely due to a high number of false-positive decisions by the Deauville score. Cut-off-independent discrimination performance remained low for both methods, but cut-off-related analyses showed promising results. Both favored the SUV_max approach, e.g. for the segregation by iPET response, where the event-free survival hazard ratio was 3.14 (95% confidence interval (CI): 2.22 – 4.46) for SUV_max and 1.70 (95% CI: 1.29 – 2.24) for the Deauville score. Conclusion: When considering treatment intensification, the currently used Deauville score cut-off of an uptake above that of the liver seems to be inappropriate and associated with potential harm for DLBCL patients. The SUV_max criterion of a relative reduction of the maximum standardized uptake value of less than or equal to 66% should be considered as an alternative.

Eve Van Cauter
Mar 1, 1992; 41:368-377
Original Article

PET using radiolabeled prostate-specific membrane antigen (PSMA) is now being more widely adopted as a valuable tool to evaluate patients with prostate cancer (PC). Recently, 3 different criteria for interpretation of PSMA PET were published: the European Association of Nuclear Medicine (EANM) criteria, the Prostate Cancer Molecular Imaging Standardized Evaluation criteria, and the PSMA Reporting and Data System. We compared these 3 criteria in terms of interreader, intrareader, and intercriteria agreement. Methods: Data from 104 patients prospectively enrolled in research protocols at our institution were retrospectively reviewed. The cohort consisted of 2 groups: 47 patients (mean age, 64.2 y old) who underwent Glu-NH-CO-NH-Lys-(Ahx)-[⁶⁸Ga(HBED-CC)] (⁶⁸Ga-PSMA11) PET/MRI for initial staging of biopsy-proven intermediate- or high-risk PC, and 57 patients (mean age, 70.5 y old) who underwent ⁶⁸Ga-PSMA11 PET/CT because of biochemically recurrent PC. Three nuclear medicine physicians independently evaluated all ⁶⁸Ga-PSMA11 PET/MRI and PET/CT studies according to the 3 interpretation criteria. Two of them reevaluated all studies 6 mo later in the same manner and masked to the initial reading. The Gwet agreement coefficient was calculated to evaluate interreader, intrareader, and intercriteria agreement based on the following sites: local lesion (primary tumor or prostate bed after radical prostatectomy), lymph node metastases, and other metastases. Results: In the PET/MRI group, interreader, intrareader, and intercriteria agreement ranged from substantial to almost perfect for any site according to all 3 criteria. In the PET/CT group, interreader agreement ranged from substantial to almost perfect except for judgment of distant metastases based on the PSMA Reporting and Data System (Gwet agreement coefficient, 0.57; moderate agreement), in which the most frequent cause of disagreement was lung nodules. Intrareader agreement ranged from substantial to almost perfect for any site according to all 3 criteria. Intercriteria agreement for each site was also substantial to almost perfect. Conclusion: Although the 3 published criteria have good interreader and intrareader reproducibility in evaluating ⁶⁸Ga-PSMA11 PET, there are some factors causing interreader disagreement. Further work is needed to address this issue.

¹⁸F-PSMA-1007 is a novel prostate-specific membrane antigen (PSMA)–based radiopharmaceutical for imaging prostate cancer (PCa). The aim of this study was to compare the diagnostic accuracy of ¹⁸F-PSMA-1007 with ⁶⁸Ga-PSMA-11 PET/CT in the same patients presenting with newly diagnosed intermediate- or high-risk PCa. Methods: Sixteen patients with intermediate- or high-risk PCa underwent ¹⁸F-PSMA-1007 and ⁶⁸Ga-PSMA-11 PET/CT within 15 d. PET findings were compared between the 2 radiotracers and with reference-standard pathologic specimens obtained from radical prostatectomy. The Cohen -coefficient was used to assess the concordance between ¹⁸F-PSMA-1007 and ⁶⁸Ga-PSMA-11 for detection of intraprostatic lesions. The McNemar test was used to assess agreement between intraprostatic PET/CT findings and histopathologic findings. Sensitivity, specificity, positive predictive value, and negative predictive value were reported for each radiotracer. SUV_max was measured for all lesions, and tumor-to-background activity was calculated. Areas under receiver-operating-characteristic curves were calculated for discriminating diseased from nondiseased prostate segments, and optimal SUV cutoffs were calculated using the Youden index for each radiotracer. Results: PSMA-avid lesions in the prostate were identified in all 16 patients with an almost perfect concordance between the 2 tracers ( ranged from 0.871 to 1). Aside from the dominant intraprostatic lesion, similarly detected by both radiotracers, a second less intense positive focus was detected in 4 patients only with ¹⁸F-PSMA-1007. Three of these secondary foci were confirmed as Gleason grade 3 lesions, whereas the fourth was shown on pathologic examination to represent chronic prostatitis. Conclusion: This pilot study showed that both ¹⁸F-PSMA-1007 and ⁶⁸Ga-PSMA-11 identify all dominant prostatic lesions in patients with intermediate- or high-risk PCa at staging. ¹⁸F-PSMA-1007, however, may detect additional low-grade lesions of limited clinical relevance.

As policymakers in a number of countries, the United States among them, debate limiting family-based immigration, this issue brief explores family-migration trends and policies in the United States, Australia, Canada, the United Kingdom, and several other European countries. Family admissions play a key role, even in countries that prioritize economic or other immigration streams.

As federal and state governments ramp up efforts to implement the Workforce Innovation and Opportunity Act, these fact sheets compare key characteristics of the foreign born and the U.S. born that are relevant to understanding needs for adult education and workforce training services. The fact sheets cover the United States, the 20 states and 25 counties with the largest immigrant populations, and New York City.

Vanita R. Aroda
Sep 1, 2019; 42:1724-1732
Emerging Therapies: Drugs and Regimens

This fact sheet compares key components of immigration reform outlined in the 2013 Senate immigration bill against provisions included in bills considered by the Senate in 2006 and 2007: border security, detention, and enforcement; worksite enforcement; visa reforms; earned legalization of unauthorized immigrants; strengthening the U.S. economy and workforce; and integration of new Americans.

MPI has completed an analysis of the major provisions in the 2013 framework, comparing them to provisions of the legislation the Senate considered in 2006 and 2007. 

This fact sheet is formatted as a chart comparing the framework of comprehensive immigration reform outlined in the 2013 Senate immigration bill against provisions included in bills considered by the Senate in 2006 and 2007.

This fact sheet offers a detailed review of the comprehensive immigration reform legislation approved by the U.S. Senate in June 2013 and compares its major provisions with those of the five targeted immigration bills approved by the House Judiciary Committee and the House Homeland Security Committee.

Abedin Haidari, Amir T. Payandeh Najafabadi, Narayanaswamy Balakrishnan.

Source: Brazilian Journal of Probability and Statistics, Volume 34, Number 1, 150--166.

Abstract:
Consider two parallel systems, say $A$ and $B$, with respective lifetimes $T_{1}$ and $T_{2}$ wherein independent component lifetimes of each system follow exponentiated generalized gamma distribution with possibly different exponential shape and scale parameters. We show here that $T_{2}$ is smaller than $T_{1}$ with respect to the usual stochastic order (reversed hazard rate order) if the vector of logarithm (the main vector) of scale parameters of System $B$ is weakly weighted majorized by that of System $A$, and if the vector of exponential shape parameters of System $A$ is unordered mojorized by that of System $B$. By means of some examples, we show that the above results can not be extended to the hazard rate and likelihood ratio orders. However, when the scale parameters of each system divide into two homogeneous groups, we verify that the usual stochastic and reversed hazard rate orders can be extended, respectively, to the hazard rate and likelihood ratio orders. The established results complete and strengthen some of the known results in the literature.

Glaura C. Franco, Helio S. Migon, Marcos O. Prates.

Source: Brazilian Journal of Probability and Statistics, Volume 33, Number 4, 756--781.

Abstract:
Observation and parameter driven models are commonly used in the literature to analyse time series of counts. In this paper, we study the characteristics of a variety of models and point out the main differences and similarities among these procedures, concerning parameter estimation, model fitting and forecasting. Alternatively to the literature, all inference was performed under the Bayesian paradigm. The models are fitted with a latent AR($p$) process in the mean, which accounts for autocorrelation in the data. An extensive simulation study shows that the estimates for the covariate parameters are remarkably similar across the different models. However, estimates for autoregressive coefficients and forecasts of future values depend heavily on the underlying process which generates the data. A real data set of bankruptcy in the United States is also analysed.

Jonathan R. Bradley, Noel Cressie, Tao Shi.

Source: Statistics Surveys, Volume 10, 100--131.

Abstract:
In this article, we review and compare a number of methods of spatial prediction, where each method is viewed as an algorithm that processes spatial data. To demonstrate the breadth of available choices, we consider both traditional and more-recently-introduced spatial predictors. Specifically, in our exposition we review: traditional stationary kriging, smoothing splines, negative-exponential distance-weighting, fixed rank kriging, modified predictive processes, a stochastic partial differential equation approach, and lattice kriging. This comparison is meant to provide a service to practitioners wishing to decide between spatial predictors. Hence, we provide technical material for the unfamiliar, which includes the definition and motivation for each (deterministic and stochastic) spatial predictor. We use a benchmark dataset of $mathrm{CO}_{2}$ data from NASA’s AIRS instrument to address computational efficiencies that include CPU time and memory usage. Furthermore, the predictive performance of each spatial predictor is assessed empirically using a hold-out subset of the AIRS data.

Aki Vehtari, Janne Ojanen.

Source: Statistics Surveys, Volume 8, , 1--1.

Abstract:
Errata for “A survey of Bayesian predictive methods for model assessment, selection and comparison” by A. Vehtari and J. Ojanen, Statistics Surveys , 6 (2012), 142–228. doi:10.1214/12-SS102.

Aki Vehtari, Janne Ojanen

Source: Statist. Surv., Volume 6, 142--228.

Abstract:
To date, several methods exist in the statistical literature for model assessment, which purport themselves specifically as Bayesian predictive methods. The decision theoretic assumptions on which these methods are based are not always clearly stated in the original articles, however. The aim of this survey is to provide a unified review of Bayesian predictive model assessment and selection methods, and of methods closely related to them. We review the various assumptions that are made in this context and discuss the connections between different approaches, with an emphasis on how each method approximates the expected utility of using a Bayesian model for the purpose of predicting future data.

An important component of every country's COVID-19 response is fast and efficient testing -- to identify and isolate cases, as well as for early detection of local hotspots. For many countries, producing a sufficient number of tests has been a serious limiting factor in their efforts to control COVID-19 infections. Group testing is a well-established mathematical tool, which can provide a serious and rapid improvement to this situation. In this note, we compare several well-established group testing schemes in the context of qPCR testing for COVID-19. We include example calculations, where we indicate which testing architectures yield the greatest efficiency gains in various settings. We find that for identification of individuals with COVID-19, array testing is usually the best choice, while for estimation of COVID-19 prevalence rates in the total population, Gibbs-Gower testing usually provides the most accurate estimates given a fixed and relatively small number of tests. This note is intended as a helpful handbook for labs implementing group testing methods.

Reinhard Heckel, Nihar B. Shah, Kannan Ramchandran, Martin J. Wainwright.

Source: The Annals of Statistics, Volume 47, Number 6, 3099--3126.

Abstract:
We consider sequential or active ranking of a set of $n$ items based on noisy pairwise comparisons. Items are ranked according to the probability that a given item beats a randomly chosen item, and ranking refers to partitioning the items into sets of prespecified sizes according to their scores. This notion of ranking includes as special cases the identification of the top-$k$ items and the total ordering of the items. We first analyze a sequential ranking algorithm that counts the number of comparisons won, and uses these counts to decide whether to stop, or to compare another pair of items, chosen based on confidence intervals specified by the data collected up to that point. We prove that this algorithm succeeds in recovering the ranking using a number of comparisons that is optimal up to logarithmic factors. This guarantee does depend on whether or not the underlying pairwise probability matrix, satisfies a particular structural property, unlike a significant body of past work on pairwise ranking based on parametric models such as the Thurstone or Bradley–Terry–Luce models. It has been a long-standing open question as to whether or not imposing these parametric assumptions allows for improved ranking algorithms. For stochastic comparison models, in which the pairwise probabilities are bounded away from zero, our second contribution is to resolve this issue by proving a lower bound for parametric models. This shows, perhaps surprisingly, that these popular parametric modeling choices offer at most logarithmic gains for stochastic comparisons.

Zhonghua Liu, Ian Barnett, Xihong Lin.

Source: The Annals of Applied Statistics, Volume 14, Number 1, 433--451.

Abstract:
Principal component analysis (PCA) is a popular method for dimension reduction in unsupervised multivariate analysis. However, existing ad hoc uses of PCA in both multivariate regression (multiple outcomes) and multiple regression (multiple predictors) lack theoretical justification. The differences in the statistical properties of PCAs in these two regression settings are not well understood. In this paper we provide theoretical results on the power of PCA in genetic association testings in both multiple phenotype and SNP-set settings. The multiple phenotype setting refers to the case when one is interested in studying the association between a single SNP and multiple phenotypes as outcomes. The SNP-set setting refers to the case when one is interested in studying the association between multiple SNPs in a SNP set and a single phenotype as the outcome. We demonstrate analytically that the properties of the PC-based analysis in these two regression settings are substantially different. We show that the lower order PCs, that is, PCs with large eigenvalues, are generally preferred and lead to a higher power in the SNP-set setting, while the higher-order PCs, that is, PCs with small eigenvalues, are generally preferred in the multiple phenotype setting. We also investigate the power of three other popular statistical methods, the Wald test, the variance component test and the minimum $p$-value test, in both multiple phenotype and SNP-set settings. We use theoretical power, simulation studies, and two real data analyses to validate our findings.

KH Britten
Dec 1, 1992; 12:4745-4765
Articles

Registries have been established in a number of countries to monitor the health of patients with cystic fibrosis. Few international comparisons have been made between registries. International data registry comparisons may be useful for informing best practice and benchmarking.

Registry comparisons are feasible but are limited by factors such as nonstandardization of data collection. Lung function was lower in Australian children with cystic fibrosis compared with their US counterparts after adjusting for the benefits of diagnosis after newborn screening. (Read the full article)

Although it has been shown that cystic fibrosis newborn screening is beneficial, the strategies vary widely, and there has been uncertainty about the costs and consequences of different algorithms and whether screening methods/decisions should be based on assumed cost differences.

This study contributes by offering a comparison of both costs, assessed comprehensively, and the consequences associated with the 2 most popular screening methodologies, immunoreactive trypsinogen/immunoreactive trypsinogen and immunoreactive trypsinogen/DNA, by using a decision-tree framework allowing variation in the model parameters. (Read the full article)

As a result of safety and environmental concerns about mercury, aneroid sphygmomanometers have replaced mercury-filled devices for blood pressure measurements. Despite this change, few studies have compared the 2 devices.

Little clinical variation exists between blood pressure measurements obtained from an aneroid or mercury device, suggesting that either device could be used in a research or clinical setting. (Read the full article)

Some studies demonstrate that adolescents have different perinatal risks and outcomes than nonadolescents. Few studies have explored the maternity experiences or practices of adolescents that may underlie these differences, or compared these with nonadolescents by using a nationally representative sample.

Adolescents and young adults were more likely to experience physical abuse, late prenatal care initiation, poor prenatal health behaviors, lower breastfeeding initiation and duration rates, postpartum depression, and lower folic acid supplementation than adult women. (Read the full article)

Evaluation of neonatal surgical outcomes is necessary to guide improvements in the quality of care. Meaningful comparisons must adjust for factors that alter outcomes independent of the surgical procedures.

Herein is described a method that permits risk adjustment for the broad range of noncardiac neonatal surgery, regardless of gestational age, to permit useful comparisons for quality improvement. (Read the full article)

Although several studies have demonstrated increased morbidity and mortality with pH1N1 in children, others have found its clinical course to be similar to seasonal influenza. Moreover, most studies were conducted at single centers, thus raising concerns about generalizability of findings.

This analysis provides national-level active hospital-based surveillance data comparing pH1N1 with 5 previous years of seasonal influenza A and demonstrates differences in risk factors and clinical presentation but not in ICU admission or mortality. (Read the full article)

Mortality of very low birth weight infants varies widely between regions and countries; however, the variation in morbidities after adjusting for confounders has not been adequately studied.

Composite outcome of mortality or short-term morbidity for very low birth weight infants was lower in Japan than in Canada. However, marked variations in mortality and individual morbidity exist, revealing areas for improvement in each country. (Read the full article)