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The co-occurrence of the 2020 Atlantic hurricane season and the ongoing coronavirus disease 2019 (COVID-19) pandemic creates complex dilemmas for protecting populations from these intersecting threats. Climate change is likely contributing to stronger, wetter, slower-moving, and more dangerous hurricanes. Climate-driven hazards underscore the imperative for timely warning, evacuation, and sheltering of storm-threatened populations – proven life-saving protective measures that gather evacuees together inside durable, enclosed spaces when a hurricane approaches. Meanwhile, the rapid acquisition of scientific knowledge regarding how COVID-19 spreads has guided mass anti-contagion strategies, including lockdowns, sheltering at home, physical distancing, donning personal protective equipment, conscientious handwashing, and hygiene practices. These life-saving strategies, credited with preventing millions of COVID-19 cases, separate and move people apart. Enforcement coupled with fear of contracting COVID-19 have motivated high levels of adherence to these stringent regulations. How will populations react when warned to shelter from an oncoming Atlantic hurricane while COVID-19 is actively circulating in the community? Emergency managers, health care providers, and public health preparedness professionals must create viable solutions to confront these potential scenarios: elevated rates of hurricane-related injury and mortality among persons who refuse to evacuate due to fear of COVID-19, and the resurgence of COVID-19 cases among hurricane evacuees who shelter together.
Introduction: Gastroenteritis accounts for 1.7 million emergency department visits by children annually in the United States. We conducted a double-blind trial to determine whether twice daily probiotic administration for 5 days, improves outcomes. Methods: 886 children aged 348 months with gastroenteritis were enrolled in six Canadian pediatric emergency departments. Participants were randomly assigned to twice daily Lactobacillus rhamnosus R0011 and Lactobacillus helveticus R0052, 4.0 x 109 CFU, in a 95:5 ratio or placebo. Primary outcome was development of moderate-severe disease within 14 days of randomization defined by a Modified Vesikari Scale score 9. Secondary outcomes included duration of diarrhea and vomiting, subsequent physician visits and adverse events. Results: Moderate-severe disease occurred in 108 (26.1%) participants administered probiotics and 102 (24.7%) participants allocated to placebo (OR 1.06; 95%CI: 0.77, 1.46; P=0.72). After adjustment for site, age, and frequency of vomiting and diarrhea, treatment assignment did not predict moderate-severe disease (OR, 1.11, 95%CI, 0.80 to 1.56; P=0.53). In the probiotic versus placebo groups, there were no differences in the median duration of diarrhea [52.5 (18.3, 95.8) vs. 55.5 (20.2, 102.3) hours; P=0.31], vomiting [17.7 (0, 58.6) vs. 18.7 (0, 51.6) hours; P=0.18], physician visits (30.2% vs. 26.6%; OR 1.19; 95% CI0.87. 1.62; P=0.27), or adverse events (32.9% vs. 36.8%; OR 0.83; 95%CI 0.62. 1.11; P=0.21). Conclusion: In children presenting to an emergency department with gastroenteritis, twice daily administration of 4.0 x 109 CFU of a Lactobacillus rhamnosus/helveticus probiotic does not prevent development of moderate-severe disease or improvements in other outcomes measured.
This paper presents the results of investigations at the ancient Maya site of Margarita in south-central Quintana Roo, Mexico, and relates them to documented patterns at neighboring centers. Following initial settlement of the region in the Middle Preclassic, settlement hierarchies topped by large centers with monumental architecture, carved monuments, and associations with sites to the south emerged in the Late Preclassic to Early Classic periods. In the Late Classic, several primary centers declined and there was a proliferation of affluent urban populations—evidenced by construction of elaborate residential groups—at smaller centers like Margarita. Long-distance cultural affiliations shifted as well, with ceramic and architectural links to western and northern Yucatán becoming pronounced. Many settlements were abandoned in the Terminal Classic, but there is also evidence of the formation of “post-collapse” communities at Margarita and other neighboring sites during the same period.
To determine the prospective relationship between changes in sugar-sweetened beverage (SSB) intake and central adiposity in older children.
Dietary intakes of children were obtained by 3 d food records at ages 10 and 13 years. Waist circumference (WC) and weight and height to determine BMI were measured at 10 and 13 years and total body fat mass (TBFM) at 13 years by dual-energy X-ray absorptiometry. Analyses were conducted using multivariable linear regression. Reporting errors were measured and participants were categorized as under-, plausible and over-reporters of dietary intakes.
Community-based British cohort of children participating in the Avon Longitudinal Study of Parents and Children.
Among 2455 older children, increased SSB consumption from ages 10 to 13 years was associated with higher WC (standardized β=0·020, P=0·19), BMI (β=0·028, P=0·03) and TBFM (β=0·017, P=0·20) at 13 years. Effects were strengthened among plausible dietary reporters (n 1059): WC (β=0·097, P<0·001), BMI (β=0·074, P<0·001) and TBFM (β=0·065, P=0·003). The association between change in SSB and WC was weakened, but remained statistically significant after accounting for BMI (β=0·042, P=0·02) and TBFM (β=0·048, P=0·01).
Higher consumption of SSB from ages 10 to 13 years was associated with a larger WC at age 13 years independent of differences in total adiposity. Accounting for dietary reporting errors strengthened associations. Our findings further support recommendations to limit intakes of SSB to reduce excess weight gain in children and suggest that SSB have an additional deleterious effect on central adiposity.
Anomalously broad diffuse interstellar bands (DIBs) at 5780.5, 5797.1, 6196.0, and 6613.6 Å are found in absorption along the line of sight to Herschel 36, an O star system next to the bright Hourglass nebula of the Hii region Messier 8. Excited lines of CH and CH+ are seen as well. We show that the region is very compact and itemize other anomalies of the gas. An infrared-bright star within 400 AU is noted. The combination of these effects produces anomalous DIBs, interpreted by Oka et al. (2013, see also this volume) as being caused predominantly by infrared pumping of rotational levels of relatively small molecules.
Recently, Sherman et al.  analyzed an M/G/1 retrial queuing model in which customers are forced to retry their service if interrupted by a server failure. Using classical techniques, they provided a stability analysis, queue length distributions, key performance parameters, and stochastic decomposition results. We analyze the system under a static Bernoulli routing policy that routes a proportion of arriving customers directly to the orbit when the server is busy or failed. In addition to providing the key performance parameters, we show that this system exhibits a dual stability structure, and we characterize the optimal Bernoulli routing policy that minimizes the total expected holding costs per unit time.
As a model for streaming multimedia applications, we study an unreliable retrial queue with infinite-capacity orbit and normal queue for which the retrial rate and the server repair rate are controllable. Customers join the retrial orbit if and only if their service is interrupted by a server failure. Interrupted customers do not rejoin the normal queue but repeatedly attempt to access the server at independent and identically distributed intervals until it is found functioning and idle. We provide stability conditions, queue length distributions, stochastic decomposition results, and performance measures. The joint optimization of the retrial and server repair rates is also studied.
In this report, we present a bio-inspired encapsulation process to create nanocluster-assembled core-shell particles under aqueous, room temperature and non-toxic conditions. The approach to synthesize calcium carbonate core-shell particles is accomplished by employing a Polymer-Induced Liquid-Precursor (PILP) process. We demonstrate the amorphous mineral precursor is coated around a core of hydrogel nanoparticles, and subsequently solidified and crystallized. The synthesized core-shell particles are 300∼500nm diameter and ∼100 nm shell-thickness. We investigate the role of the hydrogel core of the particle using time-resolved XRD, thermal-XRD and thermal analysis. The organic hydrogel appears to influence the transformation of mineral phases, stabilizing the amorphous phase of calcium carbonate.
We develop general conditions for rates of convergence and convergence
in distribution of iterative procedures for estimating finite-dimensional
parameters. An asymptotic contraction mapping condition is the centerpiece
of the theory. We illustrate some of the results by deriving the limiting
distribution of a two-stage iterative estimator of regression parameters
in a semiparametric binary response model. Simulation results illustrating
the computational benefits of the first-stage iterative estimator are also
reported.We thank a co-editor and two
referees for comments and criticisms that led to significant improvements
in this paper. We also thank Roger Klein for providing us with Gauss code
to compute his estimator.
and Θ be infinite sets and let
× Θ. We show that the class of projections of A onto
is a Vapnik–Chervonenkis (VC) class of sets if and only if
the class of projections of A onto Θ is a VC class.
We illustrate the result in the context of semiparametric estimation of a
transformation model. In this application, the VC property is hard
to establish for the projection class of interest but easy to establish for
the other projection class.
This article provides a basic report about subject recruitment processes for Web-based surveys. Using data from our ongoing Internet Survey of American Opinion project, two different recruitment techniques (banner advertisement and subscription campaigns) are compared. This comparison, together with a typology of Web-based surveys, provides insight into the validity and generalizability of Internet survey data. The results from this analysis show that, although Internet survey respondents differ demographically from the American population, the relationships among variables are similar across recruitment methods and match those implied by substantive theory. Thus, our research documents the basic methodology of subject acquisition for Web-based surveys, which, as we argue in our conclusion, may soon become the survey interview mode of choice for social scientists.
The results of structural and electrical characterizations of SrTiO3 thin films deposited onto LaAlO3 substrates by pulsed laser deposition technique are presented. The appearance of the ferroelectric phase in these films has been experimentally documented, the transition temperature being in the range of 90–120K. The hysteresis loops have been monitored in a wide temperature range by using thin film planar capacitors, the driving field being predominantly in the plane of the film. The switching properties of the films has been studied at low temperatures (∼25K) and well saturated loops have been observed with relatively low coercive field (<6kV/cm for 10μm gap). The presence of the imprint phenomenon has been also found at low temperatures.
The microstructure of the investigated SrTiO3 thin films has been studied by using a high resolution transmission electron microscope (TEM). It has been found that the annealed and as-deposited thin films, being of the same composition, have quite different microstructures. The difference observed in the polarization response of the films is related to that in their microstructure.
We establish [square root]n-consistency and asymptotic normality
of Han's (1987a, Journal of Econometrics 35, 191–209)
estimator of the parameters characterizing the transformation
function in a semiparametric transformation model. We verify
a Vapnik–Cervonenkis (VC) condition for the parameterizations
of Box and Cox (1964, Journal of the Royal Statistical Society,
Series B 34, 187–200) and Bickel and Doksum (1981,
Journal of the American Statistical Association 76,
296–311). The verification establishes the VC property
for a class of sets generated by a nonlinear function of the
transformation parameters. We also introduce a new class of
rank estimators for these parameters. These estimators require
only O(n2 logn) computations
to evaluate the criterion function, compared to
for Han's estimator. We prove that these estimators are
also [square root]n-consistent and asymptotically normal.
A simulation study compares two of the new estimators to Han's
estimator, the fully parametric estimator of Bickel and Doksum (1981),
and the nonlinear two-stage least squares estimator of Amemiya
and Powell (1981, Journal of Econometrics 17, 351–381).