Proportion Of Pairs Research Articles

Predictors of positive cerebrospinal fluid cultures in infants with bacteremia.

Meningitis causes substantial morbidity and mortality in hospitalized infants. There is no consensus on the ability of blood cultures to predict results from cerebrospinal fluid (CSF) cultures in hospitalized infants. We used the Pediatrix Medical Group database of infants discharged from 333 neonatal intensive care units between 1997 and 2011. We identified all infants with a positive blood culture and a CSF culture obtained within 3 days. We evaluated the odds of a concordant blood-CSF culture pair, controlling for severity of illness, organism type, gestational age, day of blood culture and blood-CSF culture pairing, exposure to CSF-penetrating antibiotics and the presence of a ventriculo-peritoneal shunt. We identified 8839 infants with 9408 blood-CSF culture pairs. Serratia marcescens (24/227, 11%) and Streptococcus pneumoniae (7/64, 11%) had the highest proportion of concordant blood-CSF culture pairs. The presence of a ventriculo-peritoneal shunt, as well as timing of the CSF culture on the same day as the blood culture, were associated with increased odds of blood-CSF culture pair concordance-odds ratio = 3.87 (95% confidence interval; 2.59-5.78) and 6.11 (2.81-13.24), respectively. The frequency of blood-CSF culture pair concordance is related to organism type and to the timing of the CSF culture in relation to the blood culture.

Man-induced activities modify demographic parameters in a long-lived species: effects of poisoning and health policies.

Recent changes in sanitary policies within the European Union (EU) concerning disposal of carcasses of domestic animals and the increase of non-natural mortality factors, such as illegal poisoning, are threatening European vultures. However, the effects of anthropogenic activities on demographic parameters are poorly studied. Using a long-term study (1994-2011) of the threatened Pyrenean Bearded Vulture Gypaetus barbatus population, we assess the variation in the proportion of breeding pairs, egg-laying dates, clutch size, breeding success, and survival following a sharp reduction in food availability in 2005 due to the application of restrictive sanitary policies decreasing livestock carcass availability. We found a delay in laying dates and a regressive trend in clutch size, breeding success, and survival following policy change. The maintenance of specific supplementary feeding stations for Bearded Vultures probably reduced the negative effects of illegal poisoning and food shortages, which mainly affected subadult survival. A drop in food availability may have produced changes in demographic parameters and an increase in mortality due to an increased exposure to contaminated food. As a result, supplementary feeding as a precautionary measure can be a useful tool to reduce illegal poisoning and declines in demographic parameters until previous food availability scenarios are achieved. This study shows how anthropogenic activities through human health regulations that affect habitat quality can suddenly modify demographic parameters in long-lived species, including those, such as survival, with high sensitivity to population growth rate.

Recommended tests and confidence intervals for paired binomial proportions

We describe, evaluate, and recommend statistical methods for the analysis of paired binomial proportions. A total of 24 methods are considered. The best tests for association include the asymptotic McNemar test and the McNemar mid- p test. For the difference between proportions, we recommend two simple confidence intervals with closed-form expressions and the asymptotic score interval. The asymptotic score interval is also recommended for the ratio of proportions, as is an interval with closed-form expression based on combining two Wilson score intervals for the single proportion. For the odds ratio, we recommend a transformation of the Wilson score interval and a transformation of the Clopper-Pearson mid- p interval. We illustrate the practical application of the methods using data from a recently published study of airway reactivity in children before and after stem cell transplantation and a matched case-control study of the association between floppy eyelid syndrome and obstructive sleep apnea-hypopnea syndrome.

A single-centre evaluation of two new anti-Mullerian hormone assays and comparison with the current clinical standard assay

Are the new Ansh Labs Ultra-Sensitive anti-Müllerian hormone (AMH) and picoAMH ELISA assays suitable for clinical use and is the Ultra-Sensitive assay comparable to the Beckman Coulter AMH Gen II assay? The Ultra-Sensitive assay appears to have different calibration to the Gen II assay, but has performance characteristics generally suitable for clinical use. The Gen II assay is the most commonly used AMH assay in routine biochemistry at present, but persistent calibration/interference problems have been reported. Serum from patients referred for AMH measurement was assayed (in duplicate) using the Gen II assay in Glasgow Royal Infirmary between January and February 2013. We randomly selected 193 stored serum samples to re-run (in duplicate) using the Ultra-Sensitive AMH Ansh Labs assay, blinded to the original result. Samples that returned low results were run on the picoAMH Ansh Labs assay. Performance characteristics and linearity of the new assays were also assessed. All serum samples from patients referred for AMH at Glasgow Royal Infirmary between January and February 2013 were eligible for inclusion. Investigators were blinded to any identifiable information regarding the patients, including sex, age and reason for AMH measurement. Intra-assay and inter-assay coefficients of variation of the Ultra-Sensitive and picoAMH assays were ≤6.0 and ≤10.7%, respectively, over a range of concentrations. The assays had mean linearity of 98 and 97% over the dilution range of 1:2-1:16 and 1:2-1:8, respectively. The limit of detection of the ultrasensitive assay was calculated to be 0.34 pmol/l. For 166 samples which provided a quantitative result on the Gen II and Ultra-Sensitive Ansh Labs assays, the median (interquartile range) was 12.2 (3.4-29.3) pmol/l and 20.0 (6.6-36.8) pmol/l, respectively (P<0.0001). The Passing-Bablok regression equation (in pmol/l) was y (Ultra-Sensitive) = 1.7 + 1.4 × Gen II. More samples were below the clinical cut-off of 5.4 pmol/l using the Gen II assay (a difference between paired proportions of 15.0%, P < 0.001). Fifteen of the 22 undetectable samples yielded a measurable concentration result on the picoAMH assay. The present study is a pragmatic assessment of the new assay under ideal conditions. Lot-to-lot variation could not be assessed. Demographics and outcomes of patients referred for AMH measurement were not known. The Ansh Labs Ultra-Sensitive assay performance characteristics are similar to the Gen II assay and may be suitable for clinical and epidemiological use. Enhanced sensitivity of the Ansh Labs picoAMH assay enables measurement of low AMH concentrations. These results re-emphasize the need for an AMH international standard. Ansh Labs provided kits for this study free of charge. The manufacturer played no part in conducting assays or data analysis. S.M.N. has received speaker's fees and participated in advisory boards for Beckman Coulter, Merck Serono, MSD and Ferring regarding AMH. P.W. is supported by British Heart Foundation fellowship FS/12/62/29889. We declare no other financial relationship or competing interests.

Structured Connectivity in Cerebellar Inhibitory Networks

SummaryDefining the rules governing synaptic connectivity is key to formulating theories of neural circuit function. Interneurons can be connected by both electrical and chemical synapses, but the organization and interaction of these two complementary microcircuits is unknown. By recording from multiple molecular layer interneurons in the cerebellar cortex, we reveal specific, nonrandom connectivity patterns in both GABAergic chemical and electrical interneuron networks. Both networks contain clustered motifs and show specific overlap between them. Chemical connections exhibit a preference for transitive patterns, such as feedforward triplet motifs. This structured connectivity is supported by a characteristic spatial organization: transitivity of chemical connectivity is directed vertically in the sagittal plane, and electrical synapses appear strictly confined to the sagittal plane. The specific, highly structured connectivity rules suggest that these motifs are essential for the function of the cerebellar network.

Abstract A31: Comparison of direct sequencing and peptide nucleic acid clamping of EGFR gene in patients with non-small cell lung cancer.

Abstract Background: Direct sequencing is considered as a gold standard for the detection of epidermal growth factor receptor (EGFR) gene mutation in non-small cell lung cancer (NSCLC), but low sensitivity is a problem. The aim of this study is to prove higher detection rate of EGFR mutation with peptide nucleic acid (PNA) clamping compared to direct sequencing. Methods: This is a single arm, open label, prospective, observational study for patients with stage IIIB, IV or relapsed NSCLC. A sample size of 140 pairs will have 90% power to detect a difference in proportions of 0.1 when the proportion of discordant pairs is expected to be 0.16 and the method of analysis is a McNemar's test of equality of paired proportions with a 0.05 one-sided significance level and 20% drop out rate. Tumor DNA samples were obtained from paraffin block or cytology specimen. Both direct sequencing and PNA clamping for EGFR gene in exon 18, 19, 20 and 21 were performed. Results: Of 138 paired test sets, 24 mutations of EGFR gene were detected by direct sequencing (17.4%) and 45 mutations were detected by PNA clamping (32.6%). The difference of detection rate between two methods was 15.2% (95% Confidence Interval: 8.7-17.8%, p&amp;lt;0.001). After treatment with EGFR-tyrosine kinase inhibitors, 20 of 26 response evaluable patients with EGFR mutation by PNA clamping showed partial responses (PR, 76.9%). And 8 among 13 patients with EGFR mutation by direct sequencing showed PR (61.5%). Conclusion: This study proved that PNA clamping has significantly higher detection rate of EGFR mutation compared with direct sequencing. (ClinicalTrials.gov number, NCT01767974) Citation Format: Young-Chul Kim, Seong-Hoon Yoon, Yoo-Duk Choi, In-Jae Oh, Kyu-Sik Kim, Bo-Ram Lee, Jin-Yeong Yu, Min-Ki Lee. Comparison of direct sequencing and peptide nucleic acid clamping of EGFR gene in patients with non-small cell lung cancer. [abstract]. In: Proceedings of the AACR-IASLC Joint Conference on Molecular Origins of Lung Cancer; 2014 Jan 6-9; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2014;20(2Suppl):Abstract nr A31.

When things go wrong: intra‐season dynamics of breeding failure in a seabird

During breeding, long‐lived species face important time and energy constraints that can lead to breeding failure when food becomes scarce. Despite the potential implications of intra‐season dynamics in breeding failure for individual behavior, carry‐over effects, dispersal decisions and population dynamics, little information is currently available on these dynamics at fine temporal scales. Here, we monitored the foraging behavior and the proportion of successful black‐legged kittiwake pairs from nest construction to chick fledging in a colony of the southern Barents Sea, to relate foraging effort to the dynamics of breeding failure over an entire breeding season, and to infer the environmental conditions leading to this failure. Specifically, we tracked kittiwakes with GPS and satellite tags during incubation and early chick‐rearing to document nest attendance, foraging range, time budgets and daily energy expenditures (DEE). We also monitored diet changes over time. We predicted that breeding failure would follow a non‐linear trend characterized by a break point after which breeding success would drop abruptly and would be related to a substantial increase in foraging effort. Kittiwakes showed contrasting foraging patterns between incubation and chick‐rearing: they extended their foraging range from 20 km during incubation to more than 450 km during chick‐rearing and switched diet. They also increased their DEE and readjusted their time budgets by increasing time spent at sea. These changes corresponded to a break point in breeding dynamics beyond which the proportion of successful pairs abruptly dropped. At the end of the season, less than 10% of kittiwake pairs raised chicks in the monitored plots. This integrative study confirms that breeding failure is a non‐linear process characterized by a threshold beyond which individuals face an energetic trade‐off and cannot simultaneously sustain high reproductive and self‐maintenance efforts. In this way, the occurrence of sudden environmental changes complicates our ability to predict population dynamics and poses conservation challenges.

Combat casualties undergoing lifesaving interventions have decreased heart rate complexity at multiple time scales

PurposeWe found that heart rate (HR) complexity metrics such as sample entropy (SampEn) identified patients with trauma receiving lifesaving interventions (LSIs). We now aimed (1) to test a multiscale entropy (MSE) index, (2) to compare it to single-scale measures including SampEn, and (3) to assess different parameter values for calculation of SampEn and MSE. MethodsThis was a study of combat casualties in an emergency department in Iraq. Electrocardiograms of 70 acutely injured adults were recorded. Twelve underwent LSIs and 58 did not. Lifesaving interventions included endotracheal intubation (9), tube thoracostomy (9), and emergency transfusion (4). From each electrocardiogram, a segment of 800 consecutive beats was selected. Offline, R waves were detected and R-to-R interval time series were generated. Sample entropy, MSE, and time-domain measures of HR variability (mean HR, SD, the proportion of pairs of consecutive NN intervals that differ by more than 20 and 50 milliseconds, square root of the mean of the squares of differences between adjacent NN intervals) were computed. ResultsDifferences in mean HR (LSI: 111 ± 33, non-LSI: 90 ± 17 beats/min) were not significant. Systolic arterial pressure was statistically but not clinically different (LSI: 123 ± 19, non-LSI: 135 ± 19 mm Hg). Sample entropy (LSI: 0.90 ± 0.42, non-LSI: 1.19 ± 0.35; P < .05) and MSE index (LSI: 2.58 ± 2.55, non-LSI: 5.67 ± 2.48; P < .001) differed significantly. ConclusionsComplexity of HR dynamics over a range of time scales was lower in high-risk than in low-risk combat casualties and outperformed traditional vital signs.

Clinical Relevance of 30-Minute Retention Value in Diagnosing Rapid Gastric Emptying by a Scintigraphic Test

Purpose: Currently, a 60-minute measurement of a standardized gastric emptying scintigraphy (GES) is used for diagnosis of rapid gastric emptying, and shorter intervals such as the 30-minute retention value have not been widely utilized. The purpose of our study is to determine the potential diagnostic power of the percent retention of the study meal at the 30-minute interval. Methods: We retrospectively reviewed 450 results of 4-hour GES test. Among these reports, 320 (71%) were non-delayed, of which 122 (38%) had both a 30-minute and 60-minute retention values recorded. Rapid emptying was defined as <70% retention at 30 minutes or <35% retention at 60 minutes. Statistical analysis using McNemar's test was performed to evaluate the proportion of discordant pairs between these two time intervals, and a p<0.0001 was determined to be significant. Results: Of the 122 non-delayed GES reports with both 30-minute and 60-minute retention values, 42 (34%) were classified as normal at both time points, and 46 (38%) met criteria as rapid at both intervals. Combined, the overall concordance was determined to be 72%. Additionally, 33 (27%) were classified as rapid at 30 minutes, but normal at 60 minutes, and one showed normal value at 30 minutes and rapid at 60 minutes. Among all GES reports, the 30-minute retention value classified 65% of results as rapid whereas only 38% of this group were classified as rapid at 60 minutes. Using McNemar's test, the proportion of discordant pairs was found to be significantly different between two times (p<.0001). The 30-minute interval captured 99% of the rapid cases as defined by either decreased 30-minute or 60-minute retention. Conclusion: Our analysis of GES reports with both 30-minute and 60-minute retention value demonstrated that: 1.) 30-minute interval data diagnosed an additional 27% of patients with rapid emptying as compared to the 60-minute value alone; and 2.) The addition of the 30-minute retention data significantly increases the diagnostic power of GES to identify rapid gastric emptying.

Evolution of Peromyscus leucopus Mice in Response to a Captive Environment

Many wildlife species are propagated in captivity as models for behavioral, physiological, and genetic research or to provide assurance populations to protect threatened species. However, very little is known about how animals evolve in the novel environment of captivity. The histories of most laboratory strains are poorly documented, and protected populations of wildlife species are usually too small and too short-term to allow robust statistical analysis. To document the evolutionary change in captive breeding programs, we monitored reproduction and behavior across 18 generations in six experimental populations of Peromyscus leucopus mice started from a common set of 20 wild-caught founders. The mice were propagated under three breeding protocols: a strategy to retain maximal genetic diversity, artificial selection against stereotypic behaviors that were hypothesized to reflect poor adaptation to captivity, and random bred controls. Two replicates were maintained with each protocol, and inter-replicate crosses at generations 19 and 20 were used to reverse accumulated inbreeding. We found that one of the stereotypic behaviors (repetitive flipping) was positively associated with reproductive fitness, while the other (gnawing) was relatively invariant. Selection to reduce these stereotypic behaviors caused marked reduction in reproduction, and populations not under artificial selection to reduce these behaviors responded with large increases in flipping. In non-selected populations, there was rapid evolution toward much higher proportion of pairs breeding and more rapid conception. Litter size, pup survival, and weaning mass all declined slowly, to the extent that would be predicted based on inbreeding depression. Inter-crossing between replicate populations reversed these declines in fitness components but did not reverse the changes in behavior or the accelerated breeding. These findings indicate that adaptation to captivity can be rapid, affecting reproductive patterns and behaviors, even under breeding protocols designed to minimize the rate of genetic change due to random drift and inadvertent selection.

Meiotic behaviour, karyotype analyses and pollen viability in species ofTamarix(Tamaricaceae)

Samadi N., Ghaffari S. M. & Akhani H.: Meiotic behaviour, karyotype analyses and pollen viability in species of Tamarix (Tamaricaceae). — Willdenowia 43: 195–203. June 2013. — Online ISSN 1868-6397; © 2013 BGBM Berlin-Dahlem. Stable URL: http//dx.doi.org/10.3372/wi.43.43121This study elucidates cytological aspects of the complex genus Tamarix (Tamaricaceae). Chromosome counts were performed and meiotic behaviour recorded on 30 accessions belonging to 15 taxa and three putative hybrids from different parts of Iran. Karyotype data were analysed in five species. Both gametic and somatic chromosome counts showed most species are diploid (n = 12 and 2n = 24), but polyploidy (n = 24 and 2n = 36) was found in six taxa. All the studied species showed predominance of submetacentric chromosomes and a lower proportion of metacentric pairs. The chromosomes in studied species were found to be small with a mean chromosome length of 1.05 to 2.8 µm. Karyotype analyses showed different formulas from 12sm to 7m 5sm. Pollen viability in most species was more than 79 %, with low viability (28.5 %) observed only in T. cf. kermanensis, as a triploid taxon. This study reveals that polyploidy and hybridization could be important reasons for taxonomic complexity in Tamarix. Hybridization and the high chance of establishing hybrids by vegetative reproduction are major adaptive mechanisms in the successful growing, dispersal and probable rapid evolution of this genus in its native range. Furthermore these mechanisms could facilitate the spreading of Tamarix species outside their native range as aggressive invasive plants.

Pair formation in the herbivorous rabbitfish Siganusdoliatus

This study investigated the basis of pair formation in the abundant herbivorous rabbitfish Siganus doliatus on Orpheus Island, Great Barrier Reef. Pair formation was the most common social system in S. doliatus, with 67.4% of all individuals occurring in pairs. Pairs were stable (i.e. individuals remained with the same partner throughout the study) and pair members were found within 5 m of each other 82.9% of the time. Of the examined pairs, 25% were homosexual resulting in a proportion of heterosexual pairs (75%) that was significantly lower than expected if pairs were formed solely for reproductive reasons. Therefore, although reproduction appears to be the main driver of pair formation in S. doliatus, other factors are likely to influence this behaviour. The high density of individuals on the reef crest (5.7 ± 0 .9 individuals 200 m(-2); mean ± s.e.) and extensively overlapping home ranges of pairs indicated that the defence of territories plays no role in pair formation. Instead, it appears that pair formation in S. doliatus is driven, in part, by other, non-reproductive, ecological factors. It is suggested that pair formation allows for increased vigilance against predation and enables S. doliatus to execute a novel feeding behaviour.

Evaluating the Impact of Database Heterogeneity on Observational Study Results

Clinical studies that use observational databases to evaluate the effects of medical products have become commonplace. Such studies begin by selecting a particular database, a decision that published papers invariably report but do not discuss. Studies of the same issue in different databases, however, can and do generate different results, sometimes with strikingly different clinical implications. In this paper, we systematically study heterogeneity among databases, holding other study methods constant, by exploring relative risk estimates for 53 drug-outcome pairs and 2 widely used study designs (cohort studies and self-controlled case series) across 10 observational databases. When holding the study design constant, our analysis shows that estimated relative risks range from a statistically significant decreased risk to a statistically significant increased risk in 11 of 53 (21%) of drug-outcome pairs that use a cohort design and 19 of 53 (36%) of drug-outcome pairs that use a self-controlled case series design. This exceeds the proportion of pairs that were consistent across databases in both direction and statistical significance, which was 9 of 53 (17%) for cohort studies and 5 of 53 (9%) for self-controlled case series. Our findings show that clinical studies that use observational databases can be sensitive to the choice of database. More attention is needed to consider how the choice of data source may be affecting results.

Efficient simrank-based similarity join over large graphs

Graphs have been widely used to model complex data in many real-world applications. Answering vertex join queries over large graphs is meaningful and interesting, which can benefit friend recommendation in social networks and link prediction, etc. In this paper, we adopt "SimRank" to evaluate the similarity of two vertices in a large graph because of its generality. Note that "SimRank" is purely structure dependent and it does not rely on the domain knowledge. Specifically, we define a SimRank-based join (SRJ) query to find all the vertex pairs satisfying the threshold in a data graphG. In order to reduce the search space, we propose an estimated shortest-path distance based upper bound for SimRank scores to prune unpromising vertex pairs. In the verification, we propose a novel index, called h-go cover, to efficiently compute the SimRank score of a single vertex pair. Given a graphG, we only materialize the SimRank scores of a small proportion of vertex pairs (called h-go covers), based on which, the SimRank score of any vertex pair can be computed easily. In order to handle large graphs, we extend our technique to the partition-based framework. Thorough theoretical analysis and extensive experiments over both real and synthetic datasets confirm the efficiency and effectiveness of our solution.

What Determines the Rates of Double Brooding in the Western Bluebird?

Abstract. In many bird species, double brooding (producing a second brood after successfully rearing a first) is a common reproductive strategy that can greatly increase reproductive output. However, the proportion of breeding pairs that produce a second brood varies considerably from year to year. Here, we examine how environmental factors such as weather patterns and individual factors such as clutch size, the female's body mass, and date of breeding affect the rate of double brooding in a population of the Western Bluebird (Sialia mexicana) in New Mexico. More pairs tended to produce second broods in years in which freezing ended earlier and there was warm, dry weather during the breeding season, but this pattern was apparent only when we excluded years with wildfires from the analysis. In addition, pairs that bred earlier were more likely to produce a second brood, and in these pairs females tended to be heavier. Thus both the length of the breeding season and the weather during that time influence ra...

MicroRNA‐based molecular markers: a novel PCR‐based genotyping technique in Brassica species

AbstractDNA‐based molecular markers play a significant role in gene mapping, genetic diversity analysis, germplasm evaluation and molecular marker‐assisted selection. A combination of desirable marker characteristics such as abundant polymorphism, good stability, ease of production and high efficiency is difficult to achieve when utilizing traditional molecular marker systems. MicroRNAs are a type of endogenous non‐coding RNAs prevalent in the genomes of many organisms. The high conservation of miRNA and pre‐miRNA sequences provides an opportunity to develop a novel molecular marker type. We downloaded 82 miRNA sequences from the Brassica miRBase database and designed 46 single miRNA‐based primers which could be randomly combined to generate primer pairs. A proportion of these primer pairs were validated for transferability and polymorphism using DNA from 16 varieties of six Brassica species. The percentage of polymorphic primer pairs were 28.1%, and the average polymorphism information content (PIC) value for the 34 primer pairs was 0.43. Good transferability was verified across species. These results indicate that miRNA‐based markers provide a novel genotyping technique with low costs, high efficiency, stability and good transferability.

A randomised trial of two techniques for bottle feeding preterm infants

Preterm infants begin the transition from gastric tube feeds to sucking feeds around 34 weeks' postmenstrual age. We compared physiological stability in two bottle feeding positions, cradle hold versus side lying in preterm infants. Randomised crossover trial of infants <34 weeks' gestation at birth, ≥34 weeks' postmenstrual age at study and receiving at least two sucking feeds/day. Two feeds were studied on successive days. A pulse oximeter measured oxygen saturation (SpO₂) and heart rate (HR) before, during and 30 min after feeds. Continuous data were compared using paired t-tests and proportions using chi squared. Twenty-five study infants were mean (standard deviation (SD)) 37 (2.4) weeks' post-menstrual age and 2740 (589) g at study. There was little difference in mean (SD) SpO₂ during feeds between the cradle-hold and side-lying position 94 (6) % versus 95 (6) %, respectively (P = 0.55, confidence interval (CI) -1.4, 5.4). During feeds, 17/25 (68%) experienced a period of SpO₂ <80% in the cradle-hold position compared with 14/25 (56) % in the side-lying position (P = 0.26, CI 0.68, 4.10). There were no significant differences in the mean HR or number of episodes of bradycardia HR <100 bpm. There was a trend towards infants consuming a smaller mean (SD) proportion of their feed in the cradle-hold position compared with the side-lying position, 82 (25) % versus 87 (20) % (P = 0.08, CI -0.64, 10.00). There was little difference in infants' physiological stability between the two bottle feeding positions. Both methods may be appropriate for the transition from gastric tube to sucking feeds in preterm infants.

A simplified regimen for focal radiofrequency ablation of Barrett's mucosa: a randomized multicenter trial comparing two ablation regimens

The currently recommended regimen for focal radiofrequency ablation (RFA) of Barrett's esophagus (BE) comprises 2 applications of energy, cleaning of the device and ablation zone, and 2 additional applications of energy. A simplified regimen may be of clinical utility if it is faster, easier, and equally safe and effective. To compare the efficacy of 2 focal RFA regimens. Three tertiary referral centers. Consecutive patients scheduled for focal RFA of BE with flat type BE with at least 2 BE islands or mosaic groups of islands were enrolled. BE areas were paired: 1 area was randomized to the "standard" regimen (2 × 15 J/cm(2)-clean-2 × 15 J/cm(2)) or to the "simplified" regimen (3 × 15 J/cm(2)-no clean), allocating the second area automatically to the other regimen. The percentage of surface area regression of each area was scored at 2 months by the endoscopist (blinded). Proportion of completely removed BE areas at 2 months. Calculated sample size was 46 pairs of BE areas using a noninferiority design. Noninferiority was defined as <20% difference in the paired proportions. Forty-five equivalent pairs of BE areas were included in 41 patients. The proportion of completely removed BE areas at 2 months after focal RFA was 30 (67%) for standard and 33 (73%) for simplified. Noninferiority was demonstrated by a 7% difference (95% CI, -10.6 to +20.9). Tertiary referral centers. The results of this multicenter randomized trial suggest that a simplified 3 × 15 J/cm(2) focal ablation regimen is not inferior to the standard regimen, regarding the endoscopic removal of residual Barrett islands.

Life history traits in a cyclic ecosystem: a field experiment on the arctic fox

The reproduction of many species depends strongly on variation in food availability. The main prey of the arctic fox in Fennoscandia are cyclic small rodents, and its number of litters and litter size vary depending on the phase of the rodent cycle. In this experiment, we studied if the arctic fox adjusts its reproduction as a direct response to food abundance, in accordance with the food limitation hypothesis, or if there are additional phase-dependent trade-offs that influence its reproduction. We analysed the weaning success, i.e. proportion of arctic fox pairs established during mating that wean a litter in summer, of 422 pairs of which 361 were supplementary winter fed, as well as the weaned litter size of 203 litters of which 115 were supplementary winter fed. Females without supplementary winter food over-produced cubs in relation to food abundance in the small rodent increase phase, i.e. the litter size was equal to that in the peak phase when food was more abundant. The litter size for unfed females was 6.38 in the increase phase, 7.11 in the peak phase and 3.84 in the decrease phase. The litter size for supplementary winter-fed litters was 7.95 in the increase phase, 10.61 in the peak phase and 7.86 in the decrease phase. Thus, feeding had a positive effect on litter size, but it did not diminish the strong impact of the small rodent phase, supporting phase-dependent trade-offs in addition to food determining arctic fox reproduction.

Weight changes in children in foster care for 1 year

ObjectiveThe aims of this study of predominately racial/ethnic minority children in foster care (N=360, birth to 19 years old) in Los Angeles, CA were to examine the (1) prevalence of obesity (≥95 percentile) and overweight/obese (≥85 percentile) upon entrance to foster care (T1) and after 1 year in foster care (T2); (2) comparison of high weight categories to national statistics; (3) relationship of changes in weight status to age, reason for entry into foster care, and placement. MethodsChi-square test and McNemar test comparing paired proportions were used to determine whether there were significant changes in the proportion of high weight categories between T1 and T2. Chi-square test or Fisher's exact test were used to evaluate the association between age, placement, and reason for foster care with the change in weight category. Changes in weight were categorized as (1) decreased in weight, (2) remained at overweight or obese, (3) increased in weight, or (4) remained normal. ResultsThe proportion of obese and obese/overweight children between ages 2 and 5 were significantly lower at T2 than T1. There were no significant changes in the prevalence of obesity for the total population at T2. Children age 6 or older had a higher prevalence of obesity and overweight/obesity compared to national statistics. Of children at all ages, 64.7% of children of all ages entered foster care with a normal weight and stayed in the normal range during their first year in foster care, 12.2% decreased their weight, 15.4% remained overweight or obese, and 7.7% increased their weight. Age and parental substance use was related to change in weight category from T1 to T2. ConclusionChildren did not become more overweight or obese in foster care; however 28% of the children were obese or overweight upon entry into foster care. Children who are 6 years or older and obese upon entering foster care should be targeted for weight reduction. The pediatric community and child welfare system need to work together by including weight percentiles in the foster care file and training/monitoring child welfare caregivers in weight reduction interventions.