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A hierarchical dependent Dirichlet process prior for modelling bird migration patterns in the UK

Alex Diana, Eleni Matechou, Jim Griffin, Alison Johnston.

Source: The Annals of Applied Statistics, Volume 14, Number 1, 473--493.

Abstract:
Environmental changes in recent years have been linked to phenological shifts which in turn are linked to the survival of species. The work in this paper is motivated by capture-recapture data on blackcaps collected by the British Trust for Ornithology as part of the Constant Effort Sites monitoring scheme. Blackcaps overwinter abroad and migrate to the UK annually for breeding purposes. We propose a novel Bayesian nonparametric approach for expressing the bivariate density of individual arrival and departure times at different sites across a number of years as a mixture model. The new model combines the ideas of the hierarchical and the dependent Dirichlet process, allowing the estimation of site-specific weights and year-specific mixture locations, which are modelled as functions of environmental covariates using a multivariate extension of the Gaussian process. The proposed modelling framework is extremely general and can be used in any context where multivariate density estimation is performed jointly across different groups and in the presence of a continuous covariate.




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Empirical Bayes analysis of RNA sequencing experiments with auxiliary information

Kun Liang.

Source: The Annals of Applied Statistics, Volume 13, Number 4, 2452--2482.

Abstract:
Finding differentially expressed genes is a common task in high-throughput transcriptome studies. While traditional statistical methods rank the genes by their test statistics alone, we analyze an RNA sequencing dataset using the auxiliary information of gene length and the test statistics from a related microarray study. Given the auxiliary information, we propose a novel nonparametric empirical Bayes procedure to estimate the posterior probability of differential expression for each gene. We demonstrate the advantage of our procedure in extensive simulation studies and a psoriasis RNA sequencing study. The companion R package calm is available at Bioconductor.




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Functional weak limit theorem for a local empirical process of non-stationary time series and its application

Ulrike Mayer, Henryk Zähle, Zhou Zhou.

Source: Bernoulli, Volume 26, Number 3, 1891--1911.

Abstract:
We derive a functional weak limit theorem for a local empirical process of a wide class of piece-wise locally stationary (PLS) time series. The latter result is applied to derive the asymptotics of weighted empirical quantiles and weighted V-statistics of non-stationary time series. The class of admissible underlying time series is illustrated by means of PLS linear processes and PLS ARCH processes.




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Interacting reinforced stochastic processes: Statistical inference based on the weighted empirical means

Giacomo Aletti, Irene Crimaldi, Andrea Ghiglietti.

Source: Bernoulli, Volume 26, Number 2, 1098--1138.

Abstract:
This work deals with a system of interacting reinforced stochastic processes , where each process $X^{j}=(X_{n,j})_{n}$ is located at a vertex $j$ of a finite weighted directed graph, and it can be interpreted as the sequence of “actions” adopted by an agent $j$ of the network. The interaction among the dynamics of these processes depends on the weighted adjacency matrix $W$ associated to the underlying graph: indeed, the probability that an agent $j$ chooses a certain action depends on its personal “inclination” $Z_{n,j}$ and on the inclinations $Z_{n,h}$, with $h eq j$, of the other agents according to the entries of $W$. The best known example of reinforced stochastic process is the Pólya urn. The present paper focuses on the weighted empirical means $N_{n,j}=sum_{k=1}^{n}q_{n,k}X_{k,j}$, since, for example, the current experience is more important than the past one in reinforced learning. Their almost sure synchronization and some central limit theorems in the sense of stable convergence are proven. The new approach with weighted means highlights the key points in proving some recent results for the personal inclinations $Z^{j}=(Z_{n,j})_{n}$ and for the empirical means $overline{X}^{j}=(sum_{k=1}^{n}X_{k,j}/n)_{n}$ given in recent papers (e.g. Aletti, Crimaldi and Ghiglietti (2019), Ann. Appl. Probab. 27 (2017) 3787–3844, Crimaldi et al. Stochastic Process. Appl. 129 (2019) 70–101). In fact, with a more sophisticated decomposition of the considered processes, we can understand how the different convergence rates of the involved stochastic processes combine. From an application point of view, we provide confidence intervals for the common limit inclination of the agents and a test statistics to make inference on the matrix $W$, based on the weighted empirical means. In particular, we answer a research question posed in Aletti, Crimaldi and Ghiglietti (2019).




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Convergence and concentration of empirical measures under Wasserstein distance in unbounded functional spaces

Jing Lei.

Source: Bernoulli, Volume 26, Number 1, 767--798.

Abstract:
We provide upper bounds of the expected Wasserstein distance between a probability measure and its empirical version, generalizing recent results for finite dimensional Euclidean spaces and bounded functional spaces. Such a generalization can cover Euclidean spaces with large dimensionality, with the optimal dependence on the dimensionality. Our method also covers the important case of Gaussian processes in separable Hilbert spaces, with rate-optimal upper bounds for functional data distributions whose coordinates decay geometrically or polynomially. Moreover, our bounds of the expected value can be combined with mean-concentration results to yield improved exponential tail probability bounds for the Wasserstein error of empirical measures under Bernstein-type or log Sobolev-type conditions.




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Low Information Omnibus (LIO) Priors for Dirichlet Process Mixture Models

Yushu Shi, Michael Martens, Anjishnu Banerjee, Purushottam Laud.

Source: Bayesian Analysis, Volume 14, Number 3, 677--702.

Abstract:
Dirichlet process mixture (DPM) models provide flexible modeling for distributions of data as an infinite mixture of distributions from a chosen collection. Specifying priors for these models in individual data contexts can be challenging. In this paper, we introduce a scheme which requires the investigator to specify only simple scaling information. This is used to transform the data to a fixed scale on which a low information prior is constructed. Samples from the posterior with the rescaled data are transformed back for inference on the original scale. The low information prior is selected to provide a wide variety of components for the DPM to generate flexible distributions for the data on the fixed scale. The method can be applied to all DPM models with kernel functions closed under a suitable scaling transformation. Construction of the low information prior, however, is kernel dependent. Using DPM-of-Gaussians and DPM-of-Weibulls models as examples, we show that the method provides accurate estimates of a diverse collection of distributions that includes skewed, multimodal, and highly dispersed members. With the recommended priors, repeated data simulations show performance comparable to that of standard empirical estimates. Finally, we show weak convergence of posteriors with the proposed priors for both kernels considered.




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Analysis of the Maximal a Posteriori Partition in the Gaussian Dirichlet Process Mixture Model

Łukasz Rajkowski.

Source: Bayesian Analysis, Volume 14, Number 2, 477--494.

Abstract:
Mixture models are a natural choice in many applications, but it can be difficult to place an a priori upper bound on the number of components. To circumvent this, investigators are turning increasingly to Dirichlet process mixture models (DPMMs). It is therefore important to develop an understanding of the strengths and weaknesses of this approach. This work considers the MAP (maximum a posteriori) clustering for the Gaussian DPMM (where the cluster means have Gaussian distribution and, for each cluster, the observations within the cluster have Gaussian distribution). Some desirable properties of the MAP partition are proved: ‘almost disjointness’ of the convex hulls of clusters (they may have at most one point in common) and (with natural assumptions) the comparability of sizes of those clusters that intersect any fixed ball with the number of observations (as the latter goes to infinity). Consequently, the number of such clusters remains bounded. Furthermore, if the data arises from independent identically distributed sampling from a given distribution with bounded support then the asymptotic MAP partition of the observation space maximises a function which has a straightforward expression, which depends only on the within-group covariance parameter. As the operator norm of this covariance parameter decreases, the number of clusters in the MAP partition becomes arbitrarily large, which may lead to the overestimation of the number of mixture components.




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Modeling Population Structure Under Hierarchical Dirichlet Processes

Lloyd T. Elliott, Maria De Iorio, Stefano Favaro, Kaustubh Adhikari, Yee Whye Teh.

Source: Bayesian Analysis, Volume 14, Number 2, 313--339.

Abstract:
We propose a Bayesian nonparametric model to infer population admixture, extending the hierarchical Dirichlet process to allow for correlation between loci due to linkage disequilibrium. Given multilocus genotype data from a sample of individuals, the proposed model allows inferring and classifying individuals as unadmixed or admixed, inferring the number of subpopulations ancestral to an admixed population and the population of origin of chromosomal regions. Our model does not assume any specific mutation process, and can be applied to most of the commonly used genetic markers. We present a Markov chain Monte Carlo (MCMC) algorithm to perform posterior inference from the model and we discuss some methods to summarize the MCMC output for the analysis of population admixture. Finally, we demonstrate the performance of the proposed model in a real application, using genetic data from the ectodysplasin-A receptor (EDAR) gene, which is considered to be ancestry-informative due to well-known variations in allele frequency as well as phenotypic effects across ancestry. The structure analysis of this dataset leads to the identification of a rare haplotype in Europeans. We also conduct a simulated experiment and show that our algorithm outperforms parametric methods.




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Rejoinder: Bayes, Oracle Bayes, and Empirical Bayes

Bradley Efron.

Source: Statistical Science, Volume 34, Number 2, 234--235.




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Comment: Variational Autoencoders as Empirical Bayes

Yixin Wang, Andrew C. Miller, David M. Blei.

Source: Statistical Science, Volume 34, Number 2, 229--233.




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Comment: Empirical Bayes, Compound Decisions and Exchangeability

Eitan Greenshtein, Ya’acov Ritov.

Source: Statistical Science, Volume 34, Number 2, 224--228.

Abstract:
We present some personal reflections on empirical Bayes/ compound decision (EB/CD) theory following Efron (2019). In particular, we consider the role of exchangeability in the EB/CD theory and how it can be achieved when there are covariates. We also discuss the interpretation of EB/CD confidence interval, the theoretical efficiency of the CD procedure, and the impact of sparsity assumptions.




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Comment: Empirical Bayes Interval Estimation

Wenhua Jiang.

Source: Statistical Science, Volume 34, Number 2, 219--223.

Abstract:
This is a contribution to the discussion of the enlightening paper by Professor Efron. We focus on empirical Bayes interval estimation. We discuss the oracle interval estimation rules, the empirical Bayes estimation of the oracle rule and the computation. Some numerical results are reported.




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Comment: Bayes, Oracle Bayes and Empirical Bayes

Aad van der Vaart.

Source: Statistical Science, Volume 34, Number 2, 214--218.




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Comment: Bayes, Oracle Bayes, and Empirical Bayes

Nan Laird.

Source: Statistical Science, Volume 34, Number 2, 206--208.




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Comment: Bayes, Oracle Bayes, and Empirical Bayes

Thomas A. Louis.

Source: Statistical Science, Volume 34, Number 2, 202--205.




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Bayes, Oracle Bayes and Empirical Bayes

Bradley Efron.

Source: Statistical Science, Volume 34, Number 2, 177--201.

Abstract:
This article concerns the Bayes and frequentist aspects of empirical Bayes inference. Some of the ideas explored go back to Robbins in the 1950s, while others are current. Several examples are discussed, real and artificial, illustrating the two faces of empirical Bayes methodology: “oracle Bayes” shows empirical Bayes in its most frequentist mode, while “finite Bayes inference” is a fundamentally Bayesian application. In either case, modern theory and computation allow us to present a sharp finite-sample picture of what is at stake in an empirical Bayes analysis.




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The effects of changes in the environment on the spatial firing of hippocampal complex-spike cells

RU Muller
Jul 1, 1987; 7:1951-1968
Articles




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The highly irregular firing of cortical cells is inconsistent with temporal integration of random EPSPs

WR Softky
Jan 1, 1993; 13:334-350
Articles




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The Firing of Theta State-Related Septal Cholinergic Neurons Disrupt Hippocampal Ripple Oscillations via Muscarinic Receptors

The septo-hippocampal cholinergic system is critical for hippocampal learning and memory. However, a quantitative description of the in vivo firing patterns and physiological function of medial septal (MS) cholinergic neurons is still missing. In this study, we combined optogenetics with multichannel in vivo recording and recorded MS cholinergic neuron firings in freely behaving male mice for 5.5–72 h. We found that their firing activities were highly correlated with hippocampal theta states. MS cholinergic neurons were highly active during theta-dominant epochs, such as active exploration and rapid eye movement sleep, but almost silent during non-theta epochs, such as slow-wave sleep (SWS). Interestingly, optogenetic activation of these MS cholinergic neurons during SWS suppressed CA1 ripple oscillations. This suppression could be rescued by muscarinic M2 or M4 receptor antagonists. These results suggest the following important physiological function of MS cholinergic neurons: maintaining high hippocampal acetylcholine level by persistent firing during theta epochs, consequently suppressing ripples and allowing theta oscillations to dominate.

SIGNIFICANCE STATEMENT The major source of acetylcholine in the hippocampus comes from the medial septum. Early experiments found that lesions to the MS result in the disappearance of hippocampal theta oscillation, which leads to speculation that the septo-hippocampal cholinergic projection contributing to theta oscillation. In this article, by long-term recording of MS cholinergic neurons, we found that they show a theta state-related firing pattern. However, optogenetically activating these neurons shows little effect on theta rhythm in the hippocampus. Instead, we found that activating MS cholinergic neurons during slow-wave sleep could suppress hippocampal ripple oscillations. This suppression is mediated by muscarinic M2 and M4 receptors.




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Inspiring the young generation to take action against climate change - in pictures

Climate change is what most of us perceive as the top global threat, and the dangers it poses affect present and future generations alike.  How global warming is threatening the planet has been a theme in children’s books for all ages for some time.   How everyone, especially today’s youth, can make a difference to the future of the world [...]




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Amid Pandemic, Artists Invoke Japanese Spirit Said to Protect Against Disease

Illustrators are sharing artwork of Amabie, a spirit first popularized during the Edo period, on social media




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Irish Return Historic Favor by Donating to Native Americans During Pandemic

In 1847, the Choctaw Nation sent $170—more than $5,000 today—to victims of the Irish potato famine




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Catching the Spirit of Baseball’s Opening Day

The following is a guest post by Hanna Soltys, Reference Librarian, Prints & Photographs Division. The post was written with the help of Sara W. Duke, Curator of Popular and Applied Graphic Art.   While professional baseball’s Opening Day will take place at a later date, the spirit and excitement of the day still live […]




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Enrichment of Fully Packaged Virions in Column-Purified Recombinant Adeno-Associated Virus (rAAV) Preparations by Iodixanol Gradient Centrifugation Followed by Anion-Exchange Column Chromatography

This rapid and efficient method to prepare highly purified recombinant adeno-associated viruses (rAAVs) is based on binding of negatively charged rAAV capsids to an anion-exchange resin that is pH dependent.




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Frontline Gets Personal In Flint Water Crisis Film Airing Tuesday Night

Nearly 5 ½ years ago, the water source for the city of Flint was switched in an effort to save money. A disaster followed resulting in deaths, illness and mistrust of government. Tuesday at 10:00 p.m. on WKAR-TV, the documentary series Frontlin e examines the crisis by bringing to light conversations and documents never seen on television before. We spoke with Abby Ellis, the Michigan native who is the film’s director.




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Gilles and Poirier finally win Canadian title after being 5-time runners-up

Skating to Joni Mitchell's "Both Sides Now," Piper Gilles and Paul Poirier captured their first Canadian ice dance title on Saturday.



  • Sports/Olympics/Winter Sports/Figure Skating

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Ice dancers Gilles, Poirier headline Canadian world championship team

Ice dancers Piper Gilles and Paul Poirier headline the Canadian team that will compete at this year's world figure skating championships, but Skate Canada is waiting until next month to make a final decision on several of their teammates.



  • Sports/Olympics/Winter Sports/Figure Skating

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Canada's Gilles, Poirier win ice dance silver at ISU Four Continents

Canada's Piper Gilles and Paul Poirier won the silver medal in ice dancing on Friday at the ISU Four Continents figure skating competition in Seoul, South Korea.



  • Sports/Olympics/Winter Sports/Figure Skating

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Kurt Browning clowns around to raise spirits and funds for COVID-19 relief

The Canadian four-time world champion figure skater hammed it up along with fellow Canadian skater Kaitlyn Weaver, to raise funds for the United Nation's COVID-19 Solidarity Response Fund.




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Los Angeles Rams sign former CFL all-star kicker Lirim Hajrullahu

Former CFL kicker Lirim Hajrullahu signed with the NFL's Los Angeles Rams on Monday to potentially replace veteran Greg Zuerlein.



  • Sports/Football/NFL

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Stop Airing Trump’s Briefings!

The media is allowing disinformation to appear as news.




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Essex-Windsor EMS hiring 12 'doffing' assistants to help staff remove, wash PPE

Paramedics who come back from COVID-19 related calls have to remove and either discard or wash their PPE. They are getting help from students called doffing assistants.



  • News/Canada/Windsor

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Spirited WW II vet recounts the end of the war

Tommy Parkinson, a 97-year-old British army veteran, talks about his wartime experiences, including the end of World War II.




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Firing Up a Futuristic Firetruck

We’re halfway through the SOLIDWORKS xDesign SAE Challenge, where SAE teams are hard at work designing the rescue vehicles of the future. Research is an important part of building these new machines, and we’ve got some inspiration for our design teams!

Author information

Sara Zuckerman

Sara Zuckerman is a Content Marketing Specialist in Brand Offer Marketing for SOLIDWORKS and 3DEXPERIENCE Works.

The post Firing Up a Futuristic Firetruck appeared first on SOLIDWORKS Education Blog.




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Changing the spiritual atmosphere

An OM short-term team worships God and engages in conversations about God in the public square of a city with an Arab majority in Israel.




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Irish commission: Catholic school discriminated against atheist student

CNA Staff, May 4, 2020 / 05:01 pm (CNA).- The Republic of Ireland’s Workplace Relations Commission has decided that an atheist child was discriminated against by his Catholic school when students were rewarded for attending a religious ceremony.

The commission, an independent, quasi-judicial forum, ruled that the Yellow Furze National School in County Meath had discriminated against an atheist student.

Early in the 2019 school year, the students had been promised a homework pass if they took part in the choir during a First Communion ceremony

The boy’s mother complained, but the school defended its policy.

"Any student, regardless of his/her religion in our school who opted not to participate in this extracurricular event was not 'rewarded,'" the school said, according to the Irish Post last year.

The school added that children of any religion were able to participate in the choir, and that the claim of discrimination was thus “wholly unfounded.”

The commission said the school “does not appreciate this action had an adverse effect on students who are not of a Catholic faith,” the Irish Times reported.

His mother said that "on that day my son was the only child in the class who was not participating. He was also the only non-Catholic child in the class." She added that “he came out of school crying.”

“We are atheist and this is not a choice that is open to him,” she said.

The Irish Post reported in 2019 that the boy was one of two pupils in his class of 33 to receive homework instead of attending the choir ceremony.

According to the commission the boy’s parents were “deeply hurt and upset” by the school.

“We felt that the school had disregarded the fact that we have a different set of beliefs,” the mother told RTE News. “We felt that our child had been singled out and punished for not being a Catholic,” and she added that she hoped the ruling would “change things for children here who are not Catholic".

The mother has since enrolled her son in a different school.

The commission ordered the school to pay €5,000 and demanded the school review its policies so it complies with the Equal Status Acts. The school will also have to post a memo of its compliance in a noticeable location within the school.

The mother told RTE News she will return the €5,000 to the school, “because it will be our friends and our neighbours who will be funding it, through school fundraising. We have been vindicated, but we feel that it would be wrong to accept this money.”

Catholic schools in Ireland make up 90% of all primary schools in the country, the Irish Times reported. The ruling is likely to affect how other schools promote and organize religious events.




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By the Spirit

Short-term participants from around the world joined OM for the Impact Ireland outreach to share Jesus with the people of Ireland.




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Light shines on Irish horse fair

An outreach team learns the value of sharing their personal testimonies and what a little light can do to a community.




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Donkey teaches Irish children true meaning of Christmas

The Creative Arts team perform their Christmas show for school children all over Ireland in the course of three weeks.




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Teaching spiritual and physical fitness

An OM Ukraine sports team member helps young Ukrainian women gain a healthier understanding and appreciation of the bodies God gave them.




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Repairing smiles in the Odessa province

A team of dentists and volunteers recently visited an orphanage in the Odessa province to fix 75 young smiles.




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Fin24.com | MONEY CLINIC: I'm retiring later this year. Where can I invest my R700 000 pension?

A Fin24 user set to retire in August this year is looking at options on where he can invest his pension payout.




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We CAN build a bridge to Ireland: firm's plan for eco-link across Irish sea

THE Scottish Government has been formally approached by Swedish architects proposing that a bridge to Northern Ireland can be built ... and combined with 140 wind turbines to power hundreds of thousands of homes.




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Boris Johnson: UK needs 'same spirit of national endeavour' to defeat virus as WW2 veterans showed to defeat Hitler

BORIS Johnson has said Britain needs the "same spirit of national endeavour" to defeat the coronavirus as Second World War veterans demonstrated to topple Adolf Hitler.




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Irish amateurs hold off Russia's South Region to win

Eoin Hayes's first-half strike earned the Group B points for Irish side Region 2 as Russia's South Region failed to convert their possession into a single shot on goal.




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Camley's Cartoon on Saturday, July 27: New PM's spirit of blind optimism

Framed prints of Steven Camley's cartoons are available by calling 0141 302 6210.”




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Evaluation of a Clinical Dehydration Scale in Children Requiring Intravenous Rehydration

Evaluating dehydration severity is a challenging task. Clinical dehydration scores that combine multiple clinical findings are promising. One clinical dehydration scale score has been developed and subsequently evaluated; however, few participants in the derivation and validation studies were significantly dehydrated.

In children requiring intravenous rehydration, the dehydration scale displayed moderate reliability and weak associations with objective measures. Thus, although the scale can assist in assessing dehydration, it should not be used in isolation to dictate interventions (eg, intravenous rehydration, hospitalization). (Read the full article)




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Prospective Multicenter Study of Children With Bronchiolitis Requiring Mechanical Ventilation

Bronchiolitis is one of the most common infectious respiratory conditions of early childhood, and most children have a mild clinical course. Unfortunately, the small subgroup of children requiring continuous positive airway pressure and/or intubation remains ill-defined.

In children with bronchiolitis, we found several demographic, historical, and clinical factors that predicted the need for mechanical respiratory support including in utero smoke exposure. We also found a novel subgroup of children with bronchiolitis who have a rapid respiratory decline. (Read the full article)




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Pediatric-Specific Antimicrobial Susceptibility Data and Empiric Antibiotic Selection

Ideal empirical antibiotic choices are based on local susceptibility data. These choices are important for ensuring positive patient outcomes, but pediatric-specific data may not be available.

Antibiotic susceptibilities differ by age group within a tertiary-care hospital. Knowing these differences, pediatricians chose empirical antibiotic therapy more likely to be successful. Children with infectious diseases would benefit from reporting of pediatric-specific susceptibility results. (Read the full article)




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Tracheostomy for Infants Requiring Prolonged Mechanical Ventilation: 10 Years' Experience

Advances in the treatment of critically ill infants have increased survival of extremely low/very low birth weight and medically complex infants. Improved survival can result in prolonged mechanical ventilation and sometimes tracheostomy. Current tracheostomy rates for these infants are unknown.

This long-term review of infants discharged from a NICU with tracheostomies is the first to describe tracheostomy rates specifically in extremely low/very low birth weight infants. It focuses on long-term clinical outcomes and comorbidities rather than surgical complications. (Read the full article)