bluuebunny/crossref_metadata_2025 huggingface dataset:
REFLEXÕES SOBRE A TECNOLOGIA E ADOLESCENTES: MITOS E VERDADES
Authors: Dominski Daniela Krone , Brito Débora Emerim Nunes , Santos Idegar Nunes dos , Rodrigues Juliana Alves , Moura Eliane , Esteves Cristiane Silva , Lopes Regina Maria Fernandes
Published: August 2013

O avanço tecnológico na área da informação e comunicação vem interferindo diretamente nas atividades comunicativas humanas. Este artigo aborda os mitos e verdades da relação entre a tecnologia e os adolescentes estudantes e objetiva analisar o uso excessivo da Internet por adolescentes. O método utilizado para este estudo foi indutivo e as características apresentadas apontam que o tipo de pesquisa utilizada de revisão de literatura, referente à relação do hábito de leitura e a internet, o uso adequado para acessá-la, influencia no comportamento dos adolescentes, as vantagens e desvantagens da utilização da tecnologia na educação dos estudantes adolescentes. Após a análise dos dados, buscou-se levantar os determinantes da ocorrência desse comportamento, verificar os sites mais utilizados, constatar o tempo de uso e levantar os possíveis riscos desse uso abusivo, bem como dar subsídio a novas pesquisas para se construir uma melhor forma de abordar o problema. Os resultados mostraram, qualitativamente a relevância positiva que a internet, dentre outras tecnologias, tem apresentado, abrindo um mundo de possibilidades aos estudantes da era digital.  Pesquisas recentes mostraram que o cyberbullying, tem sido denominada na literatura científica, esta nova forma de assédio realizada através da tecnologia, vem trazendo prejuízos para a população, principalmente para os pares de adolescentes
O Impacto da Sucessão de Cargos na Empresa
Authors: Mota Adriana Angelim , Campelo Maria Paula Silvestre , Almeida Neto José Leandro De
Published: August 2013

Este artigo teve o objetivo de identificar o impacto causado pela sucessão tácita de cargos em uma empresa de calçados de Juazeiro do Norte. Em busca de alcançar o aludido objetivo, utilizou-se pesquisa bibliográfica em livros e artigos e pesquisa de campo através de um questionário aplicado em todos os níveis hierárquicos da organização. Alcançou-se o seguinte resultado: A sucessão tácita de cargos leva à alta rotatividade, causando prejuízos com a demissão e recrutamento e seleção de pessoal, além de déficit em produtos e serviços da organização.
Adolescentes e suas Percepções sobre a sexualidade
Authors: Aragão Maria Suely Sampaio , Carneiro Rita Edevanira De Sá , Rocha Hidemburgo Gonçalves
Published: August 2013

O estudo do comportamento dos adolescentes frente à sexualidade tem sido de extrema importância nos estudos realizados pelos mais diversos segmentos sociais. A Psicologia, a Pedagogia além de outras áreas do conhecimento, destinaram seus olhares para este tema que é de uma imensa profundidade. Por ser o adolescente um ser em constantes conflitos com o mundo, acaba tornando-se um elemento dinâmico, sendo necessários vários estudos para que se possa compreender suas ações percepções. O termo “adolescente”, é um vocábulo já é entendido como alguém em mudança, dinâmico, evolutivo, em inúmeros estudos. O objetivo principal deste estudo é conhecer as concepções dos adolescentes relativas à sua sexualidade. Para isso, tornou-se necessário também: a) Caracterizar os sujeitos da amostra; b) Discutir aspectos ligados às concepções dos sujeitos acerca da sexualidade e, c) Analisar aspectos sócio-culturais implícitos nas concepções explicitadas pelos sujeitos. Compreender a adolescência, suas concepções e interação com o meio são fatores primordiais para que se construa um entendimento do pensamento desse grupo,  acerca de tão polêmico tema que é a sexualidade.
Exp-function Method for Fractional Differential Equations
Authors: He Ji-Huan
Published: August 2013

A fractional nonlinear wave equation is used as an example to elucidate how to solve fractional differential equations with local fractional derivatives via the fractional complex transform and the exp-function method.
Extended Reductive Perturbation Method and Its Relation to the Re-normalization Method
Authors: Demiray Hilmi
Published: August 2013

In this work, by utilizing the extended reductive perturbation method, we studied the propagation of weakly nonlinear waves in a collisionless cold plasma and formally obtained the governing evolution equations of various order terms in the perturbation expansion. The result obtained here is exactly the same with that of Kodama and Taniuti [5], who employed “so called” the re-normalization method. Seeking a progressive wave solution to these evolution equations we obtained the speed correction terms so as to remove some possible secularities. The result obtained here is consistent with the results of Malfliet and Wieers [6], who employed the dressed solitary wave method and Demiray [7], who utilized the modified reductive perturbation method.
Mechanical Characterization of Single-Crystal Silicon PV Cells
Authors: Gerosa R. , Mauri M. , Rivolta B. , Silva P.
Published: August 2013

This paper describes standard and innovative methods for characterizing the mechanical properties of single-crystal silicon cells [orientation (100)] for photovoltaic applications. The knowledge of their mechanical properties is not completely known in the technical literature and this knowledge could enhance the results of modern simulation softwares. The silicon cells were investigated before and after an aging at 100°C for 100 h. In the technical literature, an annealing at temperatures ranging from 70°C up to 180°C is proposed as a possible way to reverse the degradation of such components caused by long-time exposure to daylight (light-induced degradation, LID), and to obtain a recovery of the efficiency. Nevertheless, little information about the influence of such an annealing on the panel mechanical performances is available. Universal instrumented hardness tests were carried out to estimate the Young’s modulus; the fracture toughness was calculated by measuring the lengths of the cracks originated from the imprint corners. Moreover, the threshold load under which no cracks appear was estimated. Finally, bending tests were performed to evaluate the mechanical resistance. Such tests were carried out on a tensile testing machine after the design and the realization of suitable devices assembled on the machine standard fixtures.
Investigation of Increased Hydraulic Conductivity of Silty Till Subjected to Freeze–Thaw Cycles
Authors: Makusa Gregory P. , Mattsson Hans , Knutsson Sven
Published: August 2013

The hydraulic conductivity of silty till increases when the till is subjected to freeze–thaw cycles. A dramatic increase normally occurs after the first freeze–thaw cycle, and the magnitude generally depends on the initial or molding water content. Freezing of silty till causes aggregations of clods and the formation of macrostructure. The initial or molding water content determines the number of freeze–thaw cycles required to complete the agglomeration of clods and the formation of stable macrostructures, which in turn controls the hydraulic conductivity of compacted specimens frozen and thawed in the laboratory. The findings of this study show that for specimens compacted wet of the optimum water content, a significant increase in the hydraulic conductivity was measured after the first freeze–thaw cycle. When specimens were compacted at the optimum water content, a number of freeze–thaw cycles were required in order to obtain the corresponding significant increase in the hydraulic conductivity.
Triaxial Testing of Frozen Soils—State of the Art
Authors: Kornfield Tamra S. , Zubeck Hannele K.
Published: August 2013

Mechanical properties of frozen soils are invaluable input parameters when designing building foundations or infrastructure in perennial frost areas. Mechanical properties are also important for natural resource development in the north, such as for mining and petroleum-industry-related projects. One of these properties is the shear strength of frozen soil under varying temperatures and loading times. If shear strength is estimated instead of measured, risks for failure or overdesign exist. Therefore, it is important to accurately measure the strength of frozen soils. Two main methods exist for measuring the shear strength of soils: the direct shear test (ASTM D3080) and the triaxial compression test (ASTM D4767, ASTM D7181, and ASTM D2850). Although these tests are routinely used for unfrozen soils, not much published information exists regarding their use for frozen soils. Yet the industry needs this property for planning their operations in cold regions. Therefore, ASTM International Subcommittee D18.19 on Frozen Soils and Rock has started a process of developing new standards for mechanical properties of frozen soils. Of special interest is the dynamic triaxial testing of frozen soils. The purpose of the study reported here was to collect information and practices for the current usage of triaxial testing for frozen soil, under either static or dynamic loading conditions. According to the results of the literature review, researchers use various modified testing systems and sample configurations, and unfortunately they do not always describe them fully. So, standardization of the testing method would be beneficial for creating comparable results between laboratories. The measurement of small strains and deformations in dynamic tests was reported to be challenging. A Split-Hopkinson pressure bar is currently being developed as a means to overcome this problem. Another challenge under investigation is the accuracy of the strain rate control. The synthesized information can be used as a starting point in the development of a standard test method for the dynamic triaxial testing of frozen soils.
Freeze–Thaw Effects on Stiffness of Unbound Recycled Road Base
Authors: Bozyurt Ozlem , Keene Andrew K. , Tinjum James M. , Edil Tuncer B. , Fratta Dante
Published: August 2013

A major concern for using recycled pavement material as an unbound base or subbase layer is the effect of changing seasons on the properties of the recycled material. Three sources of recycled concrete aggregate (RCA) and recycled asphalt pavement (RAP), and one conventional base aggregate, were used to investigate the effect of freeze–thaw cycles on the stiffness of unbound road base/subbase layers. Effects of freeze–thaw cycling on the mechanical behavior of three gradations (coarse, medium, fine) of recycled materials were systematically evaluated to determine how climatic factors and aging affect the resilient modulus. Sealed specimens were exposed to 5, 10, and 20 sets of freeze–thaw cycles. Resilient modulus tests were conducted according to NCHRP 1-28A after the final freeze–thaw cycle. Freeze–thaw cycling caused a decrease in the stiffness (i.e., the summary resilient modulus) of RAP samples and class 5 aggregate because of the effect of the water retained in the pores. An increase in the stiffness of RCA was observed over 20 freeze–thaw cycles and is attributed to self-cementitious behavior of crushed concrete. Seismic modulus testing was used to investigate the continuous rate of change (daily) of the stiffness for RCA and class 5 aggregate. The seismic modulus test confirmed the trends observed in resilient modulus testing and served as a non-destructive method for tracking changes in stiffness over time and freeze–thaw cycling.
Targeted Deletion and Inversion of Tandemly Arrayed Genes in Arabidopsis thaliana Using Zinc Finger Nucleases
Authors: Qi Yiping , Li Xiaohong , Zhang Yong , Starker Colby G , Baltes Nicholas J , Zhang Feng , Sander Jeffry D , Reyon Deepak , Joung J Keith , Voytas Daniel F
Published: August 2013

Tandemly arrayed genes (TAGs) or gene clusters are prevalent in higher eukaryotic genomes. For example, approximately 17% of genes are organized in tandem in the model plant Arabidopsis thaliana. The genetic redundancy created by TAGs presents a challenge for reverse genetics. As molecular scissors, engineered zinc finger nucleases (ZFNs) make DNA double-strand breaks in a sequence-specific manner. ZFNs thus provide a means to delete TAGs by creating two double-strand breaks in the gene cluster. Using engineered ZFNs, we successfully targeted seven genes from three TAGs on two Arabidopsis chromosomes, including the well-known RPP4 gene cluster, which contains eight resistance (R) genes. The resulting gene cluster deletions ranged from a few kb to 55 kb with frequencies approximating 1% in somatic cells. We also obtained large chromosomal deletions of ~9 Mb at approximately one tenth the frequency, and gene cluster inversions and duplications also were achieved. This study demonstrates the ability to use sequence-specific nucleases in plants to make targeted chromosome rearrangements and create novel chimeric genes for reverse genetics and biotechnology.
Targeted Mutagenesis ofArabidopsis thalianaUsing Engineered TAL Effector Nucleases
Authors: Christian Michelle , Qi Yiping , Zhang Yong , Voytas Daniel F
Published: August 2013

Custom TAL effector nucleases (TALENs) are increasingly used as reagents to manipulate genomes in vivo. Here, we used TALENs to modify the genome of the model plant, Arabidopsis thaliana. We engineered seven TALENs targeting five Arabidopsis genes, namely ADH1, TT4, MAPKKK1, DSK2B, and NATA2. In pooled seedlings expressing the TALENs, we observed somatic mutagenesis frequencies ranging from 2–15% at the intended targets for all seven TALENs. Somatic mutagenesis frequencies as high as 41–73% were observed in individual transgenic plant lines expressing the TALENs. Additionally, a TALEN pair targeting a tandemly duplicated gene induced a 4.4-kb deletion in somatic cells. For the most active TALEN pairs, namely those targeting ADH1 and NATA2, we found that TALEN-induced mutations were transmitted to the next generation at frequencies of 1.5–12%. Our work demonstrates that TALENs are useful reagents for achieving targeted mutagenesis in this important plant model.
Imputation-Based Genomic Coverage Assessments of Current Human Genotyping Arrays
Authors: Nelson Sarah C , Doheny Kimberly F , Pugh Elizabeth W , Romm Jane M , Ling Hua , Laurie Cecelia A , Browning Sharon R , Weir Bruce S , Laurie Cathy C
Published: August 2013

Microarray single-nucleotide polymorphism genotyping, combined with imputation of untyped variants, has been widely adopted as an efficient means to interrogate variation across the human genome. “Genomic coverage” is the total proportion of genomic variation captured by an array, either by direct observation or through an indirect means such as linkage disequilibrium or imputation. We have performed imputation-based genomic coverage assessments of eight current genotyping arrays that assay from ~0.3 to ~5 million variants. Coverage was determined separately in each of the four continental ancestry groups in the 1000 Genomes Project phase 1 release. We used the subset of 1000 Genomes variants present on each array to impute the remaining variants and assessed coverage based on correlation between imputed and observed allelic dosages. More than 75% of common variants (minor allele frequency > 0.05) are covered by all arrays in all groups except for African ancestry, and up to ~90% in all ancestries for the highest density arrays. In contrast, less than 40% of less common variants (0.01 < minor allele frequency < 0.05) are covered by low density arrays in all ancestries and 50–80% in high density arrays, depending on ancestry. We also calculated genome-wide power to detect variant-trait association in a case-control design, across varying sample sizes, effect sizes, and minor allele frequency ranges, and compare these array-based power estimates with a hypothetical array that would type all variants in 1000 Genomes. These imputation-based genomic coverage and power analyses are intended as a practical guide to researchers planning genetic studies.
Global Linkage Map Connects Meiotic Centromere Function to Chromosome Size in Budding Yeast
Authors: Baryshnikova Anastasia , VanderSluis Benjamin , Costanzo Michael , Myers Chad L , Cha Rita S , Andrews Brenda , Boone Charles
Published: August 2013

Synthetic genetic array (SGA) analysis automates yeast genetics, enabling high-throughput construction of ordered arrays of double mutants. Quantitative colony sizes derived from SGA analysis can be used to measure cellular fitness and score for genetic interactions, such as synthetic lethality. Here we show that SGA colony sizes also can be used to obtain global maps of meiotic recombination because recombination frequency affects double-mutant formation for gene pairs located on the same chromosome and therefore influences the size of the resultant double-mutant colony. We obtained quantitative colony size data for ~1.2 million double mutants located on the same chromosome and constructed a genome-scale genetic linkage map at ~5 kb resolution. We found that our linkage map is reproducible and consistent with previous global studies of meiotic recombination. In particular, we confirmed that the total number of crossovers per chromosome tends to follow a simple linear model that depends on chromosome size. In addition, we observed a previously unappreciated relationship between the size of linkage regions surrounding each centromere and chromosome size, suggesting that crossovers tend to occur farther away from the centromere on larger chromosomes. The pericentric regions of larger chromosomes also appeared to load larger clusters of meiotic cohesin Rec8, and acquire fewer Spo11-catalyzed DNA double-strand breaks. Given that crossovers too near or too far from centromeres are detrimental to homolog disjunction and increase the incidence of aneuploidy, our data suggest that chromosome size may have a direct role in regulating the fidelity of chromosome segregation during meiosis.
The DrosophilaEnhancer of splitGene Complex: Architecture and Coordinate Regulation by Notch, Cohesin, and Polycomb Group Proteins
Authors: Schaaf Cheri A , Misulovin Ziva , Gause Maria , Koenig Amanda , Dorsett Dale
Published: August 2013

The cohesin protein complex functionally interacts with Polycomb group (PcG) silencing proteins to control expression of several key developmental genes, such as the Drosophila Enhancer of split gene complex [E(spl)-C]. The E(spl)-C contains 12 genes that inhibit neural development. In a cell line derived from the central nervous system, cohesin and the PRC1 PcG protein complex bind and repress E (spl)-C transcription, but the repression mechanisms are unknown. The genes in the E(spl)-C are directly activated by the Notch receptor. Here we show that depletion of cohesin or PRC1 increases binding of the Notch intracellular fragment to genes in the E(spl)-C, correlating with increased transcription. The increased transcription likely reflects both direct effects of cohesin and PRC1 on RNA polymerase activity at the E(spl)-C, and increased expression of Notch ligands. By chromosome conformation capture we find that the E(spl)-C is organized into a self-interactive architectural domain that is co-extensive with the region that binds cohesin and PcG complexes. The self-interactive architecture is formed independently of cohesin or PcG proteins. We posit that the E(spl)-C architecture dictates where cohesin and PcG complexes bind and act when they are recruited by as yet unidentified factors, thereby controlling the E(spl)-C as a coordinated domain.
Efficient Single-Cell Transgene Induction in Caenorhabditis elegans Using a Pulsed Infrared Laser
Authors: Churgin Matthew A , He Liping , Murray John I , Fang-Yen Christopher
Published: August 2013

The coupling of transgenes to heat shock promoters is a widely applied method for regulating gene expression. In C. elegans, gene induction can be controlled temporally through timing of heat shock and spatially via targeted rescue in heat shock mutants. Here, we present a method for evoking gene expression in arbitrary cells, with single-cell resolution. We use a focused pulsed infrared laser to locally induce a heat shock response in specific cells. Our method builds on and extends a previously reported method using a continuous-wave laser. In our technique, the pulsed laser illumination enables a much higher degree of spatial selectivity because of diffusion of heat between pulses. We apply our method to induce transient and long-term transgene expression in embryonic, larval, and adult cells. Our method allows highly selective spatiotemporal control of transgene expression and is a powerful tool for model organism biology.
Complex Genetic Effects on Early Vegetative Development Shape Resource Allocation Differences BetweenArabidopsis lyrataPopulations
Authors: Remington David L , Leinonen Päivi H , Leppälä Johanna , Savolainen Outi
Published: August 2013

Costs of reproduction due to resource allocation trade-offs have long been recognized as key forces in life history evolution, but little is known about their functional or genetic basis. Arabidopsis lyrata, a perennial relative of the annual model plant A. thaliana with a wide climatic distribution, has populations that are strongly diverged in resource allocation. In this study, we evaluated the genetic and functional basis for variation in resource allocation in a reciprocal transplant experiment, using four A. lyrata populations and F2 progeny from a cross between North Carolina (NC) and Norway parents, which had the most divergent resource allocation patterns. Local alleles at quantitative trait loci (QTL) at a North Carolina field site increased reproductive output while reducing vegetative growth. These QTL had little overlap with flowering date QTL. Structural equation models incorporating QTL genotypes and traits indicated that resource allocation differences result primarily from QTL effects on early vegetative growth patterns, with cascading effects on later vegetative and reproductive development. At a Norway field site, North Carolina alleles at some of the same QTL regions reduced survival and reproductive output components, but these effects were not associated with resource allocation trade-offs in the Norway environment. Our results indicate that resource allocation in perennial plants may involve important adaptive mechanisms largely independent of flowering time. Moreover, the contributions of resource allocation QTL to local adaptation appear to result from their effects on developmental timing and its interaction with environmental constraints, and not from simple models of reproductive costs.
High-Throughput Computer Vision Introduces the Time Axis to a Quantitative Trait Map of a Plant Growth Response
Authors: Moore Candace R , Johnson Logan S , Kwak Il-Youp , Livny Miron , Broman Karl W , Spalding Edgar P
Published: August 2013

Automated image acquisition, a custom analysis algorithm, and a distributed computing resource were used to add time as a third dimension to a quantitative trait locus (QTL) map for plant root gravitropism, a model growth response to an environmental cue. Digital images of Arabidopsis thaliana seedling roots from two independently reared sets of 162 recombinant inbred lines (RILs) and one set of 92 near isogenic lines (NILs) derived from a Cape Verde Islands (Cvi) × Landsberg erecta (Ler) cross were collected automatically every 2 min for 8 hr following induction of gravitropism by 90° reorientation of the sample. High-throughput computing (HTC) was used to measure root tip angle in each of the 1.1 million images acquired and perform statistical regression of tip angle against the genotype at each of the 234 RIL or 102 NIL DNA markers independently at each time point using a standard stepwise procedure. Time-dependent QTL were detected on chromosomes 1, 3, and 4 by this mapping method and by an approach developed to treat the phenotype time course as a function-valued trait. The QTL on chromosome 4 was earliest, appearing at 0.5 hr and remaining significant for 5 hr, while the QTL on chromosome 1 appeared at 3 hr and thereafter remained significant. The Cvi allele generally had a negative effect of 2.6–4.0%. Heritability due to the QTL approached 25%. This study shows how computer vision and statistical genetic analysis by HTC can characterize the developmental timing of genetic architectures.
Quantifying Population Genetic Differentiation from Next-Generation Sequencing Data
Authors: Fumagalli Matteo , Vieira Filipe G , Korneliussen Thorfinn Sand , Linderoth Tyler , Huerta-Sánchez Emilia , Albrechtsen Anders , Nielsen Rasmus
Published: August 2013

Over the past few years, new high-throughput DNA sequencing technologies have dramatically increased speed and reduced sequencing costs. However, the use of these sequencing technologies is often challenged by errors and biases associated with the bioinformatical methods used for analyzing the data. In particular, the use of naïve methods to identify polymorphic sites and infer genotypes can inflate downstream analyses. Recently, explicit modeling of genotype probability distributions has been proposed as a method for taking genotype call uncertainty into account. Based on this idea, we propose a novel method for quantifying population genetic differentiation from next-generation sequencing data. In addition, we present a strategy for investigating population structure via principal components analysis. Through extensive simulations, we compare the new method herein proposed to approaches based on genotype calling and demonstrate a marked improvement in estimation accuracy for a wide range of conditions. We apply the method to a large-scale genomic data set of domesticated and wild silkworms sequenced at low coverage. We find that we can infer the fine-scale genetic structure of the sampled individuals, suggesting that employing this new method is useful for investigating the genetic relationships of populations sampled at low coverage.
Natural History of Stuttering to 4 Years of Age: A Prospective Community-Based Study
Authors: Reilly Sheena , Onslow Mark , Packman Ann , Cini Eileen , Conway Laura , Ukoumunne Obioha C. , Bavin Edith L. , Prior Margot , Eadie Patricia , Block Susan , Wake Melissa
Published: August 2013

OBJECTIVES:

To document the natural history of stuttering by age 4 years, including (1) cumulative incidence of onset, (2) 12-month recovery status, (3) predictors of stuttering onset and recovery, and (4) potential comorbidities. The study cohort was a prospective community-ascertained cohort (the Early Language in Victoria Study) from Melbourne, Australia, of 4-year-old children (n = 1619; recruited at age 8 months) and their mothers.

METHODS:

Outcome was stuttering onset by age 4 years and recovery within 12 months of onset, defined using concurrent monthly parent and speech pathologist ratings. Potential predictors: child gender, birth weight, birth order, prematurity, and twinning; maternal mental health and education; socioeconomic status; and family history of stuttering. Potential comorbidities: preonset and concurrent temperament, language, nonverbal cognition, and health-related quality of life.

RESULTS:

By age 4 years, the cumulative incidence of stuttering onset was 11.2% (95% confidence interval [CI]: 9.7% to 12.8%). Higher maternal education (P = .004), male gender (P = .02), and twinning (P = .005) predicted stuttering onset. At outcome, stuttering children had stronger language (mean [SD]: 105.0 [13.0] vs 99.6 [14.6]; mean difference 5.5, 95% CI: 3.1 to 7.8; P < .001) and nonverbal cognition (mean [SD]: 106.5 [11.4] vs 103.9 [13.7], mean difference 2.6, 95% CI: 0.4 to 4.8; P = .02) and better health-related quality of life but were otherwise similar to their nonstuttering peers. Only 9 of 142 children (6.3%; 95% CI: 2.9% to 11.7%) recovered within 12 months of onset.

CONCLUSIONS:

Although stuttering onset is common in preschoolers, adverse affects are not the norm in the first year after onset.
Measuring Hospital Quality Using Pediatric Readmission and Revisit Rates
Authors: Bardach Naomi S. , Vittinghoff Eric , Asteria-Peñaloza Renée , Edwards Jeffrey D. , Yazdany Jinoos , Lee Henry C. , Boscardin W. John , Cabana Michael D. , Dudley R. Adams
Published: August 2013

OBJECTIVE:

To assess variation among hospitals on pediatric readmission and revisit rates and to determine the number of high- and low-performing hospitals.

METHODS:

In a retrospective analysis using the State Inpatient and Emergency Department Databases from the Healthcare Cost and Utilization Project with revisit linkages available, we identified pediatric (ages 1–20 years) visits with 1 of 7 common inpatient pediatric conditions (asthma, dehydration, pneumonia, appendicitis, skin infections, mood disorders, and epilepsy). For each condition, we calculated rates of all-cause readmissions and rates of revisits (readmission or presentation to the emergency department) within 30 and 60 days of discharge. We used mixed logistic models to estimate hospital-level risk-standardized 30-day revisit rates and to identify hospitals that had performance statistically different from the group mean.

RESULTS:

Thirty-day readmission rates were low (<10.0%) for all conditions. Thirty-day rates of revisit to the inpatient or emergency department setting ranged from 6.2% (appendicitis) to 11.0% (mood disorders). Study hospitals (n = 958) had low condition-specific visit volumes (37.0%–82.8% of hospitals had <25 visits). The only condition with >1% of hospitals labeled as different from the mean on 30-day risk-standardized revisit rates was mood disorders (4.2% of hospitals [n = 15], range of hospital performance 6.3%–15.9%).

CONCLUSIONS:

We found that when comparing hospitals’ performances to the average, few hospitals that care for children are identified as high- or low-performers for revisits, even for common pediatric diagnoses, likely due to low hospital volumes. This limits the usefulness of condition-specific readmission or revisit measures in pediatric quality measurement.
ADHD and Learning Disabilities in Former Late Preterm Infants: A Population-Based Birth Cohort
Authors: Harris Malinda N. , Voigt Robert G. , Barbaresi William J. , Voge Gretchen A. , Killian Jill M. , Weaver Amy L. , Colby Christopher E. , Carey William A. , Katusic Slavica K.
Published: August 2013

BACKGROUND AND OBJECTIVE:

Previous studies suggest that former late preterm infants are at increased risk for learning and behavioral problems compared with term infants. These studies have primarily used referred clinical samples of children followed only until early school age. Our objective was to determine the cumulative incidence of attention deficit/hyperactivity disorder (ADHD) and learning disabilities (LD) in former late preterm versus term infants in a population-based birth cohort.

METHODS:

Subjects included all children born 1976 to 1982 in Rochester, MN who remained in the community after 5 years. This study focused on the comparison of subjects in 2 subgroups, late preterm (34 to <37 weeks) and term (37 to <42 weeks). School and medical records were available to identify individuals who met research criteria for ADHD and LD in reading, written language, and math. The Kaplan-Meier method was used to estimate the cumulative incidence of each condition by 19 years of age. Cox models were fit to evaluate the association between gestational age group and condition, after adjusting for maternal education and perinatal complications.

RESULTS:

We found no statistically significant differences in the cumulative incidence of ADHD or LD between the late preterm (N = 256) versus term (N = 4419) groups: ADHD (cumulative incidence by age 19 years, 7.7% vs 7.2%; P = .84); reading LD (14.2% vs 13.1%; P = .57); written language LD (13.5% vs 15.7%; P = .36), and math LD (16.1% vs 15.5%; P = .89).

CONCLUSIONS:

These data from a population-based birth cohort indicate that former late preterm infants have similar rates of LD and ADHD as term infants.
Caregiver-Fabricated Illness in a Child: A Manifestation of Child Maltreatment
Authors: Flaherty Emalee G. , MacMillan Harriet L. ,   COMMITTEE ON CHILD ABUSE AND NEGLECT, Christian Cindy W. , Crawford-Jakubiak James E. , Flaherty Emalee G. , Leventhal John M. , Lukefahr James L. , Sege Robert D.
Published: August 2013

Caregiver-fabricated illness in a child is a form of child maltreatment caused by a caregiver who falsifies and/or induces a child’s illness, leading to unnecessary and potentially harmful medical investigations and/or treatment. This condition can result in significant morbidity and mortality. Although caregiver-fabricated illness in a child has been widely known as Munchausen syndrome by proxy, there is ongoing discussion about alternative names, including pediatric condition falsification, factitious disorder (illness) by proxy, child abuse in the medical setting, and medical child abuse. Because it is a relatively uncommon form of maltreatment, pediatricians need to have a high index of suspicion when faced with a persistent or recurrent illness that cannot be explained and that results in multiple medical procedures or when there are discrepancies between the history, physical examination, and health of a child. This report updates the previous clinical report “Beyond Munchausen Syndrome by Proxy: Identification and Treatment of Child Abuse in the Medical Setting.” The authors discuss the need to agree on appropriate terminology, provide an update on published reports of new manifestations of fabricated medical conditions, and discuss approaches to assessment, diagnosis, and management, including how best to protect the child from further harm.
Effect of Metal Extension of Crown in the Screw Access Channel of a Posterior Implant Abutment on the Retention of Cement Retained Prosthesis
Authors: Biyani Rashmi , Ali Mohsin , Belles Donald , Powers John M.
Published: August 2013

Purpose: Reducing the height of the implant abutment due to limited interarch space decreases the surface area for retention of cemented restorations. The purpose of this in vitro study was to see whether engaging the screw access channel with metal extension compensates for the loss of retention of posterior crowns cemented on shorter abutments. Material and Methods: Four identical prefabricated abutments were mounted on implant replicas embedded in acrylic resin blocks. Three of these abutments were reduced in height by 1 mm, 2 mm, and 3 mm respectively and one was left unmodified. Two sets of base metal crowns were fabricated for each abutment, one without and one with the metal extension inside the screw access channel. The crowns were cemented using Tempbond NE. The tensile forces required to separate the cemented crowns from abutments were measured using an Instron testing machine. Statistical analysis of the data was performed using a 2-way analysis of variance and Fisher's protected least significant difference at 0.05 level of significance. Results: An increase of 24% to 261% in retentive forces was observed for the group having metal extension in the screw access channel. Statistically significant differences (P < .001) were found among 2 types of crowns and four heights of abutments. Generally, the retentive forces were reduced in magnitude as the abutment height was reduced. Conclusion: The retention of a casting cemented to posterior implant abutments is influenced by the height of the abutment and the metal extension engaging the screw access channel. The crowns made with a metal extension showed superior retention values.
Early Treatment Protocol for Skeletal Class III Malocclusion
Authors: Oltramari-Navarro Paula Vanessa Pedron , Almeida Renato Rodrigues de , Conti Ana Cláudia de Castro Ferreira , Navarro Ricardo de Lima , Almeida Marcio Rodrigues de , Fernandes Leandra Sant'Anna Ferreira Parron
Published: August 2013

Skeletal Class III malocclusion, with its unpredictable and unfavorable nature, has been characterized by a growth pattern with doubtful prognosis regarding orthodontic mechanics, even when performed early. For a long time, Class III malocclusion was regarded as a synonym of mandibular prognathism, regardless of the affected skeletal structures. Mandibular growth, essentially determined by genetic factors, could barely be controlled by early orthodontic interventions. Therefore, the treatment choice was to wait for the patient to grow, and then make an orthodontic intervention associated with an orthognathic surgery. Maxillary involvement in the etiology of Class III malocclusion was conclusive to change orthodontic therapeutics. Maxillary intramembranous growth has a better response to orthopedic treatment, based on growth control and redirection, thus contributing for early intervention success. In several cases, excellent results have been achieved with rapid maxillary expansion and protraction. The aim of this study was to describe and discuss the treatment of a patient with Class III malocclusion, whose treatment planning comprised two phases: interceptive (mechanical orthopedic appliances) and comprehensive (fixed orthodontic appliance). The results of this case showed that Class III malocclusion should be intercepted as early as possible to permit growth redirection, mainly when the maxilla is the primary etiologic factor or dental and/or functional factors are involved. Diagnosis, treatment planning and prognosis depend on patient age, growth potential and severity of malocclusion. Early intervention, adequate indication of appliances, and patient compliance are key factors for good outcomes.
A methodology to measure cervical vertebral bone maturation in a sample from low-income children
Authors: Aguiar Luciana Barreto Vieira , Caldas Maria de Paula , Haiter Neto Francisco , Ambrosano Glaucia Maria Bovi
Published: August 2013

This study evaluated the applicability of the regression method for determining vertebral age developed by Caldas et al. (2007) by testing this method in children from low-income families of the rural zone. The sample comprised cephalometric and hand-wrist radiographs of 76 boys and 64 girls aged 7.0 to 14.9 years living in a medium-sized city in the desert region of the northeastern region of Brazil, with an HDI of 0.678. C3 and C4 vertebrae were traced and measured on cephalometric radiographs to estimate the bone age. The average age, average hand-wrist age and average error estimated for girls and boys were, respectively, 10.62 and 10.44 years, 11.28 and 10.57 years, and 1.42 and 1.18 years. Based on these results, the formula proposed by Caldas et al. (2007) was not applicable to the studied population, and new multiple regression models were developed to obtain the children's vertebral bone age accurately.
Use of glass ionomer cement containing antibiotics to seal off infected dentin: a randomized clinical trial
Authors: Ferreira Jainara Maria Soares , Pinheiro Sérgio Luiz , Sampaio Fábio Correia , Menezes Valdenice Aparecida de
Published: August 2013

Dental materials with antibacterial properties can prevent the harmful effects caused by oral cariogenic bacteria. This double-blind controlled clinical trial evaluated the performance of a glass ionomer cement (GIC) added with antibiotics for sealing infected dentin in atraumatic restorations of primary molars. The study enrolled 45 children (45 teeth) between 5 and 8 years of age, of both genders, divided into two groups: GC (n=22), where cavities were lined with a conventional GIC (Vidrion F) and GA (n=23), with cavities lined with Vidrion F added with 1% each of metronidazole, ciprofloxacin and cefaclor antibiotic. Both groups were restored with Ketac Molar Easymix. Molars with carious lesions on the inner half of dentin without clinical or radiographic pulp damage were selected. Patients were evaluated clinically (pain, fistulas or mobility) and radiographically (area of caries, periapical region and furcation) after 1, 3, 6 and 12 months. For statistical analysis, chi-squared or Fisher's exact tests were used with a 5% significance level. GA (82.6-95.7%) had better results than GC (12.5-36.4%) in all evaluations (p<0.05) and the difference in the success rate was 46.2-72.5% higher for GA. The use of the antibiotic-containing GIC liner on infected dentin proved satisfactory when applied in deciduous teeth.
Sealing Ability of MTA Used as a Root End Filling Material: Effect of the Sonic and Ultrasonic Condensation
Authors: Bernabé Pedro Felício Estrada , Gomes-Filho João Eduardo , Bernabé Daniel Galera , Nery Mauro Juvenal , Otoboni-Filho José Arlindo , Dezan-Jr Eloi , Cintra Luciano Tavares Angelo
Published: August 2013

Despite the excellent properties of mineral trioxide aggregate (MTA), the condensation technique may have some influence in its sealing ability. The purpose of this study was to compare the sealing ability of sonic and ultrasonic setting of MTA. Thirty-four extracted human teeth had their canals prepared and filled with Sealapex sealer and gutta-percha using the active lateral condensation technique. The teeth were rendered waterproof and apicoectomy performed at 3 mm from the apex. Root-end cavities (3.0 mm deep and 1.4 mm diameter) were prepared with diamond ultrasonic tips. The root-end cavities were filled with Pro-Root MTA® with ultrasonic vibration, sonic vibration or no vibration. The positive control group did not receive any material while the negative control group was totally rendered waterproof. After material set, the specimens were immersed in Rodhamine B for 24 h, under vacuum in the first 15 min, then washed, dried and split longitudinally for evaluating the infiltration at the dentin/material interface. Data were analyzed using ANOVA and Tukey's tests at 5% significance level. Sonic vibration promoted the lowest infiltration values (p<0.05). It was concluded that sonic vibration could be considered an efficient aid to improve the sealing ability of MTA when used as root-end filling material.
Effect of investment type and mold temperature on casting accuracy and titanium-ceramic bond
Authors: Leal Mônica Barbosa , Pagnano Valéria Oliveira , Bezzon Osvaldo Luiz
Published: August 2013

This study evaluated the casting accuracy of crown margins and metal-ceramic shear bond strength (SBS) of pure titanium injected into casting molds made using 2 investment types at 3 mold temperatures. Sixty crown (30-degree beveled finish line) and 60 cylinder (5 mm diameter × 8 mm high) patterns were divided into 6 groups (n=10), and cast using a phosphate-bonded investment (P) and a magnesium oxide-bonded investment (U), at 400°C (groups P400 and U400), 550°C (groups P550 and U550) and 700°C (groups P700 and U700) mold temperatures. Crown margins were recorded in impression material, the degree of marginal rounding was measured and margin length deficiencies (µm) were calculated. Titanium-ceramic specimens were prepared using Triceram ceramic (2 mm high) and SBS was tested. Failure modes were assessed by optical microscopy. Data were subjected to two-way ANOVA and Tukey's HSD test (α=0.05). For casting accuracy, expressed by marginal deficiency (µm), investment U provided more accurate results (64 ± 11) than P (81 ± 23) (p<0.001). The increase in temperature resulted in different effects for the tested investments (p<0.001), as it provided better casting accuracy for U700 (55 ± 7) and worse for P700 (109 ± 18). Casting accuracy at 700°C (82 ± 31) was significantly different from 400°C (69 ± 9) and 550°C (68 ± 9) (p<0.05). For SBS, there was no significant differences among the groups for factors investment (p=0.062) and temperature (p=0.224), or for their interaction (p=0.149). Investment U provided better casting accuracy than investment P. The SBS was similar for all combinations of investments and temperatures.
Morphological, Functional and Biochemical Characterization of Canine Gingival Fibroblasts
Authors: Pelegrini Camila Bonvicino , Maia Luciana Prado , Souza Sérgio Luís Scombatti de , Taba Jr Mário , Palioto Daniela Bazan
Published: August 2013

As dogs are good models for in vivo studies, it is interesting to evaluate the behavior of canine gingival fibroblasts (CGF) in vitro, so that these cells could be seeded on a matrix and later studied in vivo. The aim of this study was to perform a morphological, functional and biochemical analysis of CGF, comparing it with human gingival fibroblasts (HGF), as well as to evaluate the change of their characteristics over several passages. Using gingival fibroblasts from 3 dogs and 3 humans in the subculture (Sub), first (P1), third (P3), fifth (P5) and seventh (P7) passages, the following parameters were assessed: cell morphology, spreading, adhesion, viability and total protein content. The results showed no major differences between the passages in terms of morphology and spreading, and a tendency of greater adhesion and viability for HGF when compared with CGF. The total protein content was significantly higher for HGF. HGF exhibited greater functional and biochemical activity in vitro compared to CGF. Higher numbers at Sub were observed for both CGF and HGF in all evaluated parameters. The differences do not prevent the use of CGF for tissue engineering, but its use seems to be more appropriate in the subculture or first passage.
Color Stability, Surface Roughness and Flexural Strength of an Acrylic Resin Submitted to Simulated Overnight Immersion in Denture Cleansers
Authors: Paranhos Helena de Freitas Oliveira , Peracini Amanda , Pisani Marina Xavier , Oliveira Viviane de Cássia , Souza Raphael Freitas de , Silva-Lovato Cláudia Helena
Published: August 2013

This study evaluated color stability, surface roughness and flexural strength of acrylic resin specimens after immersion in alkaline peroxide and alkaline hypochlorite, simulating a period of one and a half year of use of overnight immersion. Sixty disc-shaped (16X4 mm) and 80 rectangular specimens (65X10X3.3 mm) were prepared from heat-polymerized acrylic resin (Lucitone 550) and distributed into 4 groups (n=20): C1: without immersion, C2: 8 h immersion in distilled water; AP: 8 h immersion in alkaline peroxide effervescent tablet; SH: 8 h immersion in 0.5% NaOCl solution. Properties were evaluated at baseline and after the immersion. Color data were also calculated according the National Bureau of Standards (NBS). Results were analyzed statistically by ANOVA and Tukey's HSD test (α=0.05). AP (2.34 ± 0.41) caused color alteration significantly higher than C2 (0.39 ± 0.30) and SH (1.73 ± 0.52). The mean ΔE values were classified as indicial for C2 (0.36 ± 0.29) and noticeable for AP (2.12 ± 0.39) and SH (1.59 ± 0.48). SH (0.0195 ± 0.0150) caused significantly higher ΔRa (p=0.000) than the C2 (0.0005 ± 0.0115) and PA (0.0005 ± 0.0157) groups. There was no statistically significant difference (p=0.063) among the solutions for flexural strength (C1: 105.43 ± 14.93, C2: 100.30 ± 12.43, PA: 97.61 ± 11.09, SH: 95.23 ± 10.18). In conclusion, overnight immersion in denture cleansing solutions simulating a year and a half of use did not alter the flexural strength of acrylic resin but caused noticeable color alterations, higher for alkaline peroxide. The 0.5% NaOCl solution caused increase in surface roughness.