¹⁶⁶Ho-microspheres have recently been approved for clinical use for hepatic radioembolization in the European Union. The aim of this study was to investigate the absorbed dose–response relationship and its association with overall survival for ¹⁶⁶Ho radioembolization in patients with liver metastases. Methods: Patients treated in the HEPAR I and II studies who underwent an ¹⁸F-FDG PET/CT scan at baseline, a posttreatment ¹⁶⁶Ho SPECT/CT scan, and another ¹⁸F-FDG PET/CT scan at the 3-mo follow-up were included for analysis. The posttreatment ¹⁶⁶Ho-microsphere activity distributions were estimated with quantitative SPECT/CT reconstructions using a quantitative Monte Carlo–based method. The response of each tumor was based on the change in total lesion glycolysis (TLG) between baseline and follow-up and was placed into 1 of 4 categories, according to the PERCIST criteria, ranging from complete response to progressive disease. Patient-level response was grouped according to the average change in TLG per patient. The absorbed dose–response relationship was assessed using a linear mixed model to account for correlation of tumors within patients. Median overall survival was compared between patients with and without a metabolic liver response, using a log-rank test. Results: Thirty-six patients with a total of 98 tumors were included. The relation between tumor-absorbed dose and both tumor-level and patient-level response was explored. At a tumor level, a significant difference in geometric mean absorbed dose was found between complete response (232 Gy; 95% confidence interval [CI], 178–303 Gy; n = 32) and stable disease (147 Gy; 95% CI, 113–191 Gy; n = 28) (P = 0.01) and between complete response and progressive disease (117 Gy; 95% CI, 87–159 Gy; n = 21) (P = 0.0008). This constitutes a robust absorbed dose–response relationship. At a patient level, a significant difference was found between patients with complete or partial response (210 Gy; 95% CI, 161–274 Gy; n = 13) and patients with progressive disease (116 Gy; 95% CI, 81–165 Gy; n = 9) (P = 0.01). Patients were subsequently grouped according to their average change in TLG. Patients with an objective response (complete or partial) exhibited a significantly higher overall survival than nonresponding patients (stable or progressive disease) (median, 19 mo vs. 7.5 mo; log-rank, P = 0.01). Conclusion: These results confirm a significant absorbed dose–response relationship in ¹⁶⁶Ho radioembolization. Treatment response is associated with a higher overall survival.

With more than 3 million Venezuelans having fled their country in crisis, this event features the release of an MPI-OAS report that examines the creative responses that host countries in Latin America are providing. These include the opening of legal pathways to residence, access to formal labor markets, and greater use of forms of ID for recognition.

Ralph A. DeFronzo
Oct 1, 2013; 36:3169-3176
Emerging Technologies and Therapeutics

Joseph Henson
Jan 1, 2016; 39:130-138
IDF-ADA Translational Symposium

OBJECTIVE

The long-term influences of sex hormone administration on insulin sensitivity and incretin hormones are controversial. We investigated these effects in 35 transgender men (TM) and 55 transgender women (TW) from the European Network for the Investigation of Gender Incongruence (ENIGI) study.

The ADA and nearly 100 other organizations are asking Congress and the White House to help businesses survive the coronavirus crisis by reducing their costs and increasing their cash flow as much as possible in the coming weeks.

The ADA is calling on dentists everywhere to contact their legislators today ahead of the Senate’s vote on the Coronavirus Aid, Relief and Economic Security Act.

As the Senate works to pass a stimulus package aimed at granting relief to the millions of Americans affected by the COVID-19 pandemic, the ADA is thanking dentists across the nation for making their voices heard in Washington on that same legislation.

The U.S. Department of Labor Wage and Hour Division released new guidance March 26 to help workers and employers understand provisions included in the Families First Coronavirus Response Act.

The Commission on Dental Accreditation announced April 3 that it directed all CODA-accredited dental programs to submit a report by May 15 on their use of distance learning, enhanced activities and other educational modalities in response to the COVID-19 pandemic.

The second round of results from the ADA Health Policy Institute poll on the impact of COVID-19 on dental practices showed significant financial impact, with collections for the vast majority of dentists less than 5% of what is typical in their practice.

The third round of results from the ADA Health Policy Institute poll on the impact of COVID-19 on dental practices was released April 27, with 79% of dentists reporting their practices are closed except for emergencies and 17% are closed completely.

What happens when the police are called to handle a mental health emergency? And is the current coronavirus pandemic affecting their response? In today’s podcast, Gabe interviews Sergeant Matt Harris,...

As maritime arrivals climbed in 2015, EU policymakers struggled to mount a coordinated response. A range of ad hoc crisis-response tools emerged, but many officials worry that if another migration emergency were to hit Europe, the European Union may still be unprepared. This report traces the evolution of the EU response to the 2015–16 crisis and lays out recommendations to lock in progress and shore up weaknesses.

Six million immigrant workers are at the frontlines of keeping U.S. residents healthy and fed during the COVID-19 pandemic, representing disproportionate shares of physicians, home health aides, and retail-store pharmacists, for example. They also are over-represented in sectors most immediately devastated by mass layoffs, yet many will have limited access to safety-net systems and to federal relief, as this fact sheet details.

Brussels and Gütersloh, 05.03.2020 — Anticipated reform of the Common European Asylum System (CEAS), which was high on the agenda as nearly 2 million asylum seekers arrived at Europe’s door in 2015-16, quickly fell victim to EU Member State competing views on what constitutes equal burden-sharing, domestic politics around migration and the urgency of first addressing overtaxed national asylum systems.

WASHINGTON — Six million immigrant workers are at the frontlines of keeping U.S. residents healthy, safe and fed during the COVID-19 pandemic, according to a Migration Policy Institute (MPI) analysis of U.S. Census Bureau data issued today. While the foreign born represented 17 percent of the 156 million civilians working in 2018, they account for larger shares in pandemic-response frontline occupations: 29 percent of all physicians in the United States, 38 percent of home health aides and 23 percent of retail-store pharmacists, for example.

Felipe Muñoz, Advisor to the President of Colombia for the Colombian-Venezuelan Border, discusses how Colombia is coping with the influx of Venezuelan migrants, plans for future policy decisions surrounding this migration, and developments in regional and international cooperation.

Leading policymakers and key stakeholders from Latin America, as well as representatives of major international institutions, offer their views on the challenges ahead as Latin American governments seek to chart strategies for responding to large-scale forced migration flows, such as those from Venezuela and Nicaragua.

This webinar marks the release of MPI's Latin American and Caribbean Migration Portal that offers up-to-date, authoritative research and data on migration trends and policies, and a report examining the policy responses of 11 countries in Latin America and the Caribbean to increased Venezuelan and Nicaraguan migration.

Large-scale displacement from Venezuela and Nicaragua is reshaping the migration landscape in much of Latin America and the Caribbean. This report, accompanied by the launch of a new Migration Portal offering research and analysis on the region, examines the immigration and integration policy responses of 11 countries, including pathways to legal status and measures to integrate newcomers into schools, health-care systems, and labor markets.

Felipe Muñoz, Advisor to the President of Colombia for the Colombian-Venezuelan Border, discusses how Colombia is coping with the influx of Venezuelan migrants, plans for future policy decisions surrounding this migration, and developments in regional and international cooperation.

Leading policymakers and key stakeholders from Latin America, as well as representatives of major international institutions, offer their views on the challenges ahead as Latin American governments seek to chart strategies for responding to large-scale forced migration flows, such as those from Venezuela and Nicaragua. Spanish and English versions of the remarks are available.

Fleeing crisis, nearly 4 million Venezuelans have moved to other Latin American and Caribbean countries over the past few years. This webinar marked the launch of a Latin American and Caribbean Migration Portal, and a report examining the migration and integration policy responses in the region. 

From Hong Kong, South China Morning Post CEO Gary Liu tracks China's response to the coronavirus pandemic -- from the initial outbreak in Wuhan to the shutdown of Hubei province and the containment measures taken across its major cities. Sharing insights into how the culture in places like Hong Kong and South Korea contributed to fast action against the virus, Liu identifies lessons people across the world can use to stop its spread. (This virtual conversation is part of the TED Connects series, hosted by head of TED Chris Anderson and current affairs curator Whitney Pennington Rodgers. Recorded March 25, 2020)

To combat COVID-19, countries have enforced city-wide shutdowns, stay-at-home orders and mask mandates -- but the reaction (and adherence) to these rules has differed markedly in the East and West. In conversation with TED's head of curation Helen Walters, writer and publisher Huang Hung sheds light on how Chinese and American cultural values shaped their responses to the outbreak -- and provides perspective on why everyone needs to come together to end the pandemic. (Recorded April 16, 2020)

"We have a responsibility to save lives," Ohio Gov. Mike DeWine said on Twitter. "We could have waited to close schools, but based on advice from health experts, this is the time to do it."

A Nebraska senator introduced a bill that would give teachers legal cover to physically restraint disruptive students, prompting a strong positive response from members of the state teachers' union.

"Educators are completely redesigning instructional delivery while constantly being thrown new rules. It's like 'flying the plane as you build it,'" says Maddie Fennell.

The state wants to test its middle school students in the mathematics courses in which they're enrolled, rather than with the state tests created for that each student's particular grade.

What have states actually done in response to U.S. Department of Education feedback on their plans for the Every Student Succeeds Act? Here's Delaware's answer.

Reaction time.

Rockville, Maryland : National Institute on Drug Abuse, 1987.

Sufficient dimension reduction (SDR) is a very useful concept for exploratory analysis and data visualization in regression, especially when the number of covariates is large. Many SDR methods have been proposed for regression with a continuous response, where the central subspace (CS) is the target of estimation. Various conditions, such as the linearity condition and the constant covariance condition, are imposed so that these methods can estimate at least a portion of the CS. In this paper we study SDR for regression and discriminant analysis with categorical response. Motivated by the exploratory analysis and data visualization aspects of SDR, we propose a new geometric framework to reformulate the SDR problem in terms of manifold optimization and introduce a new concept called Maximum Separation Subspace (MASES). The MASES naturally preserves the “sufficiency” in SDR without imposing additional conditions on the predictor distribution, and directly inspires a semi-parametric estimator. Numerical studies show MASES exhibits superior performance as compared with competing SDR methods in specific settings.

Uttam Bandyopadhyay, Shirsendu Mukherjee, Atanu Biswas.

Source: Brazilian Journal of Probability and Statistics, Volume 34, Number 2, 291--303.

Abstract:
In adaptive crossover design, our goal is to allocate more patients to a promising treatment sequence. The present work contains a very simple three period crossover design for two competing treatments where the allocation in period 3 is done on the basis of the data obtained from the first two periods. Assuming normality of response variables we use a reliability functional for the choice between two treatments. We calculate the allocation proportions and their standard errors corresponding to the possible treatment combinations. We also derive some asymptotic results and provide solutions on related inferential problems. Moreover, the proposed procedure is compared with a possible competitor. Finally, we use a data set to illustrate the applicability of the proposed design.

Caio L. N. Azevedo, Dalton F. Andrade

Source: Braz. J. Probab. Stat., Volume 24, Number 3, 415--433.

Abstract:
The nominal response model (NRM) was proposed by Bock [ Psychometrika 37 (1972) 29–51] in order to improve the latent trait (ability) estimation in multiple choice tests with nominal items. When the item parameters are known, expectation a posteriori or maximum a posteriori methods are commonly employed to estimate the latent traits, considering a standard symmetric normal distribution as the latent traits prior density. However, when this item set is presented to a new group of examinees, it is not only necessary to estimate their latent traits but also the population parameters of this group. This article has two main purposes: first, to develop a Monte Carlo Markov Chain algorithm to estimate both latent traits and population parameters concurrently. This algorithm comprises the Metropolis–Hastings within Gibbs sampling algorithm (MHWGS) proposed by Patz and Junker [ Journal of Educational and Behavioral Statistics 24 (1999b) 346–366]. Second, to compare, in the latent trait recovering, the performance of this method with three other methods: maximum likelihood, expectation a posteriori and maximum a posteriori. The comparisons were performed by varying the total number of items (NI), the number of categories and the values of the mean and the variance of the latent trait distribution. The results showed that MHWGS outperforms the other methods concerning the latent traits estimation as well as it recoveries properly the population parameters. Furthermore, we found that NI accounts for the highest percentage of the variability in the accuracy of latent trait estimation.

When the response mechanism is believed to be not missing at random (NMAR), a valid analysis requires stronger assumptions on the response mechanism than standard statistical methods would otherwise require. Semiparametric estimators have been developed under the model assumptions on the response mechanism. In this paper, a new statistical test is proposed to guarantee model identifiability without using any instrumental variable. Furthermore, we develop optimal semiparametric estimation for parameters such as the population mean. Specifically, we propose two semiparametric optimal estimators that do not require any model assumptions other than the response mechanism. Asymptotic properties of the proposed estimators are discussed. An extensive simulation study is presented to compare with some existing methods. We present an application of our method using Korean Labor and Income Panel Survey data.

This paper deals with robust marginal estimation under a general regression model when missing data occur in the response and also in some of covariates. The target is a marginal location parameter which is given through an $M-$functional. To obtain robust Fisher--consistent estimators, properly defined marginal distribution function estimators are considered. These estimators avoid the bias due to missing values by assuming a missing at random condition. Three methods are considered to estimate the marginal distribution function which allows to obtain the $M-$location of interest: the well-known inverse probability weighting, a convolution--based method that makes use of the regression model and an augmented inverse probability weighting procedure that prevents against misspecification. The robust proposed estimators and the classical ones are compared through a numerical study under different missing models including clean and contaminated samples. We illustrate the estimators behaviour under a nonlinear model. A real data set is also analysed.

Uncertainties in a structure is inevitable, which generally lead to variation in dynamic response predictions. For a complex structure, brute force Monte Carlo simulation for response variation analysis is infeasible since one single run may already be computationally costly. Data driven meta-modeling approaches have thus been explored to facilitate efficient emulation and statistical inference. The performance of a meta-model hinges upon both the quality and quantity of training dataset. In actual practice, however, high-fidelity data acquired from high-dimensional finite element simulation or experiment are generally scarce, which poses significant challenge to meta-model establishment. In this research, we take advantage of the multi-level response prediction opportunity in structural dynamic analysis, i.e., acquiring rapidly a large amount of low-fidelity data from reduced-order modeling, and acquiring accurately a small amount of high-fidelity data from full-scale finite element analysis. Specifically, we formulate a composite neural network fusion approach that can fully utilize the multi-level, heterogeneous datasets obtained. It implicitly identifies the correlation of the low- and high-fidelity datasets, which yields improved accuracy when compared with the state-of-the-art. Comprehensive investigations using frequency response variation characterization as case example are carried out to demonstrate the performance.

Xin Bing, Marten H. Wegkamp.

Source: The Annals of Statistics, Volume 47, Number 6, 3157--3184.

Abstract:
We consider the multivariate response regression problem with a regression coefficient matrix of low, unknown rank. In this setting, we analyze a new criterion for selecting the optimal reduced rank. This criterion differs notably from the one proposed in Bunea, She and Wegkamp ( Ann. Statist. 39 (2011) 1282–1309) in that it does not require estimation of the unknown variance of the noise, nor does it depend on a delicate choice of a tuning parameter. We develop an iterative, fully data-driven procedure, that adapts to the optimal signal-to-noise ratio. This procedure finds the true rank in a few steps with overwhelming probability. At each step, our estimate increases, while at the same time it does not exceed the true rank. Our finite sample results hold for any sample size and any dimension, even when the number of responses and of covariates grow much faster than the number of observations. We perform an extensive simulation study that confirms our theoretical findings. The new method performs better and is more stable than the procedure of Bunea, She and Wegkamp ( Ann. Statist. 39 (2011) 1282–1309) in both low- and high-dimensional settings.

Bo Ning, Seonghyun Jeong, Subhashis Ghosal.

Source: Bernoulli, Volume 26, Number 3, 2353--2382.

Abstract:
We study frequentist properties of a Bayesian high-dimensional multivariate linear regression model with correlated responses. The predictors are separated into many groups and the group structure is pre-determined. Two features of the model are unique: (i) group sparsity is imposed on the predictors; (ii) the covariance matrix is unknown and its dimensions can also be high. We choose a product of independent spike-and-slab priors on the regression coefficients and a new prior on the covariance matrix based on its eigendecomposition. Each spike-and-slab prior is a mixture of a point mass at zero and a multivariate density involving the $ell_{2,1}$-norm. We first obtain the posterior contraction rate, the bounds on the effective dimension of the model with high posterior probabilities. We then show that the multivariate regression coefficients can be recovered under certain compatibility conditions. Finally, we quantify the uncertainty for the regression coefficients with frequentist validity through a Bernstein–von Mises type theorem. The result leads to selection consistency for the Bayesian method. We derive the posterior contraction rate using the general theory by constructing a suitable test from the first principle using moment bounds for certain likelihood ratios. This leads to posterior concentration around the truth with respect to the average Rényi divergence of order $1/2$. This technique of obtaining the required tests for posterior contraction rate could be useful in many other problems.

M. W. McLean, M. P. Wand.

Source: Bayesian Analysis, Volume 14, Number 2, 371--398.

Abstract:
We build on recent work concerning message passing approaches to approximate fitting and inference for arbitrarily large regression models. The focus is on regression models where the response variable is modeled to have an elaborate distribution, which is loosely defined to mean a distribution that is more complicated than common distributions such as those in the Bernoulli, Poisson and Normal families. Examples of elaborate response families considered here are the Negative Binomial and $t$ families. Variational message passing is more challenging due to some of the conjugate exponential families being non-standard and numerical integration being needed. Nevertheless, a factor graph fragment approach means the requisite calculations only need to be done once for a particular elaborate response distribution family. Computer code can be compartmentalized, including that involving numerical integration. A major finding of this work is that the modularity of variational message passing extends to elaborate response regression models.

Vincent Dorie, Jennifer Hill, Uri Shalit, Marc Scott, Dan Cervone.

Source: Statistical Science, Volume 34, Number 1, 94--99.

Abstract:
Response to discussion of Dorie (2017), in which the authors of that piece express their gratitude to the discussants, rebut some specific criticisms, and argue that the limitations of the 2016 Atlantic Causal Inference Competition represent an exciting opportunity for future competitions in a similar mold.

Amanda Avona
May 29, 2019; 39:4323-4331
Systems/Circuits

Joshua A. Gordon
May 15, 1996; 16:3274-3286
Articles

MN Shadlen
Feb 15, 1996; 16:1486-1510
Articles