bluuebunny/crossref_metadata_2025_split huggingface dataset:
‘I've stuck to the path I'm afraid’: exploring student non‐use of blended learning
Authors: Orton‐Johnson Kate 
Published: July 2008

AbstractThis paper draws on qualitative data from a study of student use of blended learning as part of a conventionally taught undergraduate Sociology course. Findings from an early evaluation questionnaire highlighted an overwhelming pattern of non‐use of the materials and subsequent research with a group of 16 students evidenced limited and inconsistent engagement with the resources. In an analysis of the category ‘non‐use’, the students’ rejection of the materials is seen to be closely related to a trust in traditional texts as authentic academic knowledge and an instrumental and strategic approach to study. Blended learning resources are shown to challenge existing learning patterns and practices, reconfigure existing understandings and expectations of academic scholarship and reconstruct academic boundaries in new spaces.
Diversity in the School Problems of Economically Disadvantaged Adolescents: Dual Pathways of Reading and Externalizing Problems
Authors: Ackerman Brian , Smith Clare , Kobak Roger 
Published: July 2008

AbstractThis study of economically disadvantaged 13‐year‐olds examined the relations between serious reading difficulties and clinical levels of externalizing behaviors in school. The variable‐centered results showed that family variables, adolescent verbal ability, and negative emotion patterns differed in uniquely predicting reading achievement and externalizing behaviors. The person‐centered analyses established robust groups of adolescents showing problems in a single domain, both domains, or neither domain, and that family and adolescent variables distinguished the adolescent groups in predictable ways. Longitudinal results available for a subsample showed that high problem levels for the groups were stable across elementary school and associated with first‐grade characteristics. The results provide evidence for relatively independent pathways of reading and externalizing difficulties for young disadvantaged adolescents.
Who Dislikes Whom, and For Whom Does It Matter: Predicting Aggression in Middle Childhood
Authors: Erath Stephen A. , Pettit Gregory S. , Dodge Kenneth A. , Bates John E. 
Published: July 2008

AbstractThis study investigated the role of mutual dislike dyads (MDDs) in the development of aggressive behavior across the middle childhood years. Of particular interest was whether involvement in MDDs predicted later aggression, and whether the magnitude of the association between MDDs and later aggression varied based on characteristics of target children and ‘others’ involved in their MDDs. Data were collected on a community sample of 453 children participating in an ongoing longitudinal study. Classroom peer nomination and rating‐scale measures were collected in kindergarten through third grade; aggressive behavior problems were assessed via teacher ratings in the early elementary years (kindergarten and first grade) and late elementary years (fourth and fifth grade). MDD involvement in the middle elementary years (second and third grade) was associated with higher levels of aggression in the late elementary years among boys (but not girls), and these predictions held after controlling for group‐level peer disliking in the middle elementary years, aggression in the early elementary years, and demographic variables. The association between MDD involvement and subsequent aggression was also qualified by the aggressiveness of others in children's MDDs: Having more MDDs predicted later aggression only among boys whose MDDs involved mostly non‐aggressive others.
Generalization of Jeffreys Divergence-Based Priors for Bayesian Hypothesis Testing
Authors: Bayarri M. J. , García-Donato G. 
Published: July 2008

SummaryWe introduce objective proper prior distributions for hypothesis testing and model selection based on measures of divergence between the competing models; we call them divergence-based (DB) priors. DB priors have simple forms and desirable properties like information (finite sample) consistency and are often similar to other existing proposals like intrinsic priors. Moreover, in normal linear model scenarios, they reproduce the Jeffreys–Zellner–Siow priors exactly. Most importantly, in challenging scenarios such as irregular models and mixture models, DB priors are well defined and very reasonable, whereas alternative proposals are not. We derive approximations to the DB priors as well as Markov chain Monte Carlo and asymptotic expressions for the associated Bayes factors.
DASSO: Connections Between the Dantzig Selector and Lasso
Authors: James Gareth M. , Radchenko Peter , Lv Jinchi 
Published: July 2008

SummaryWe propose a new algorithm, DASSO, for fitting the entire coefficient path of the Dantzig selector with a similar computational cost to the least angle regression algorithm that is used to compute the lasso. DASSO efficiently constructs a piecewise linear path through a sequential simplex-like algorithm, which is remarkably similar to the least angle regression algorithm. Comparison of the two algorithms sheds new light on the question of how the lasso and Dantzig selector are related. In addition, we provide theoretical conditions on the design matrix X under which the lasso and Dantzig selector coefficient estimates will be identical for certain tuning parameters. As a consequence, in many instances, we can extend the powerful non-asymptotic bounds that have been developed for the Dantzig selector to the lasso. Finally, through empirical studies of simulated and real world data sets we show that in practice, when the bounds hold for the Dantzig selector, they almost always also hold for the lasso.
Correlation of Population Parameters Leading to Power Differences In Association Studies with Population Stratification
Authors: He Y. , Jiang R. , Fu W. , Bergen A. W. , Swan G. E. , Jin L. 
Published: July 2008

SummaryThe power of statistical tests to measure effect sizes in the presence of population stratification is an important issue for the design and analysis of population‐based association studies. Comparisons of statistical tests have shown that the power of different statistical approaches varies in different genetic scenarios. However, the impact of stratified population parameters on statistical power is not yet understood in a general statistical framework, particularly the impact of correlated population parameters. To investigate such impact in detail, we implemented a genetic model for population‐based association studies with stratified samples and evaluated the impact on power with different genetic scenarios. The investigation shows that correlation between disease prevalence and risk allele frequency among subpopulations impacts statistical power. In a model with five subpopulations and moderate population divergence (Fst= 0.01), the correlation accounts for more than 85% of power difference. Our results also show that the estimation of genetic effect for candidate loci is biased by population divergence. Beneficial alleles could be wrongly characterized as risk alleles when prevalence differences and divergences of risk loci are large among subpopulations.
Can the Allelic Test be Retired from Analysis of Case‐Control Association Studies?
Authors: Zheng Gang 
Published: July 2008

SummaryIt has been stated that, when Hardy‐Weinberg equilibrium (HWE) holds in the combined case‐control samples, the allelic test is asymptotically equivalent to the trend test (for the additive model) for testing genetic association, and hence the allelic test should not be used. A recent publication shows that the allelic test and the trend test are asymptotically equivalent when HWE holds in the population. It is known that, when HWE does not hold, the trend test can still be used while the allelic test is no longer valid. Therefore, the allelic test is either not valid or is asymptotically equivalent to the trend test. It appears that the allelic test is a nuisance test. Can it be retired from the analysis of case‐control association studies? It all depends on data and model assumptions. We give conditions under which the allelic test and the trend test are asymptotically equivalent under both null and alternative hypotheses.
Probability that a Two‐Stage Genome‐Wide Association Study will Detect a Disease‐Associated SNP and Implications for Multistage Designs
Authors: Gail M. H. , Pfeiffer R. M. , Wheeler W. , Pee D. 
Published: July 2008

SummaryLarge two‐stage genome‐wide association studies (GWASs) have been shown to reduce required genotyping with little loss of power, compared to a one‐stage design, provided a substantial fraction of cases and controls, πsample, is included in stage 1. However, a number of recent GWASs have used πsample < 0.2. Moreover, standard power calculations are not applicable because SNPs are selected in stage 1 by ranking their p‐values, rather than comparing each SNP's statistic to a fixed critical value. We define the detection probability (DP) of a two‐stage design as the probability that a given disease‐associated SNP will have a p‐value among the lowest ranks of p‐values at stage 1, and, among those SNPs selected at stage 1, at stage 2. For 8000 cases and 8000 controls available for study and for odds ratios per allele in the range 1.1‐1.3, we show that DP is substantially reduced for designs with πsample≤ 0.25, and that DP cannot be appreciably increased by analyzing the stage 1 and stage 2 data jointly. These results suggest that multistage designs with small first stages (e.g. πsample≤ 0.25) should be avoided, and that additional genotyping in earlier studies with small first stages will yield previously unselected disease‐associated SNPs.
Dystrophin Nonsense Mutations Can Generate Alternative Rescue Transcripts in Lymphocytes
Authors: Nishiyama A. , Takeshima Y. , Zhang Z. , Habara Y. , Tran T. H. T. , Yagi M. , Matsuo M. 
Published: July 2008

SummarySecondary alterations in splicing have been reported to produce semi‐functional mRNA from several nonsense mutations in the dystrophin gene. Disruptions of exonic splicing enhancers by single nucleotide changes are thought to underlie such alterations. The precise frequencies of such nonsense mutation‐dependent splicing alterations, however, remain unknown. Here we analyzed the splicing patterns of dystrophin mRNA in lymphocytes from 38 patients with dystrophinopathies due to nonsense mutations in the dystrophin gene. In seven of the cases (18%), we observed partial skipping of the nonsense‐encoding exon. Two of the seven cases, however, exhibited complex activation of a nonsense mutation‐created splice site, which resulted in the generation of novel transcripts. Examination of cis‐regulatory splicing elements through calculation of splicing probability scores and identification of potential splicing enhancer or silencer sequences failed to disclose a single cause for exon skipping. Remarkably, individual differences in splicing patterns were observed for cells from patients with identical nonsense mutations (C.5899C>T). Although five cases produced semi‐functional dystrophin mRNAs, only one of these exhibited a mild clinical course. These results provide important insights about targets for exon skipping induced by candidate antisense oligonucleotides and for ribosomal read‐through of nonsense mutations.
Differences in startle reflex and prepulse inhibition in European‐Americans and African‐Americans
Authors: Hasenkamp Wendy , Norrholm Seth D. , Green Amanda , Lewison Barbara , Boshoven William , Keyes Megan , Duncan Erica 
Published: July 2008

AbstractThe acoustic startle reflex and its modulation by a prepulse are psychophysiological phenomena that are commonly studied to evaluate various aspects of information processing. Recent reports in human populations suggest that subjects from disparate racial backgrounds may have significant differences in the startle response. To determine if this pattern could be observed in our subject population and whether it extended to prepulse inhibition (PPI), we evaluated baseline startle parameters and PPI in 53 African‐Americans (AA) and 38 European‐Americans (EA). In AA compared to EA, mean startle magnitude and probability of blink response were lower, with no difference in habituation. PPI was greater in AA than EA when groups were matched on baseline startle magnitude. These findings support the idea of racial differences in startle response. Implications for study design are highlighted, and possible environmental and genetic influences are considered.
Superior temporal gyrus spectral abnormalities in schizophrenia
Authors: Edgar J. Christopher , Hanlon Faith M. , Huang Ming‐Xiong , Weisend Michael P. , Thoma Robert J. , Carpenter Bruce , Hoechstetter Karsten , Cañive José M. , Miller Gregory A. 
Published: July 2008

AbstractConsiderable evidence indicates early auditory stimulus processing abnormalities in schizophrenia, but the mechanisms are unclear. The present study examined oscillatory phenomena during a paired‐click paradigm in the superior temporal gyrus (STG) as a possible core problem. The primary question addressed is whether first click and/or second click group differences in the time‐domain evoked response in patients with schizophrenia are due to (1) group differences in the magnitude of poststimulus oscillatory activity, (2) group differences in poststimulus phase‐locking, and/or (3) group differences in the magnitude of ongoing background oscillatory activity. Dense‐array magnetoencephalography from 45 controls and 45 patients with schizophrenia produced left‐ and right‐hemisphere STG 50‐ and 100‐ms time‐frequency evoked, phase‐locking, and total power measures. Whereas first click 100‐ms evoked theta and alpha abnormalities were observed bilaterally, evoked low beta‐band differences were specific to the left hemisphere. Compared to controls, patients with schizophrenia showed more low‐frequency phase variability, and the decreased 100‐ms S1 evoked response observed in patients was best predicted by the STG phase‐locking measure.
Underlying mechanisms of the P3a task‐difficulty effect
Authors: Kimura Motohiro , Katayama Jun'ichi , Murohashi Harumitsu 
Published: July 2008

AbstractIn three‐stimulus oddball studies, even typical deviant stimuli elicited a large P3a event‐related brain potential (ERP) when target/standard discrimination was difficult. To investigate the underlying mechanisms, the effects of task difficulty on early deviant‐related ERPs were assessed. Four visual stimuli defined by an orthogonal combination of task‐relevant size (nontarget 80%, target 20%) and task‐irrelevant luminance (standard 80%, deviant 20%) were presented randomly, where two task difficulties (easy, difficult) were defined by target/nontarget discriminability. An increase in task difficulty enhanced P3a as well as a posterior negativity (change‐related negativity) and an anterior positivity (frontal positivity) elicited by deviant nontarget stimuli. These results suggest that attentional modulation of refractoriness‐based rareness detection and an attention‐triggering process underlie the P3a task‐difficulty effect.
Unvoluntary attentional capture in change blindness
Authors: Schankin Andrea , Wascher Edmund 
Published: July 2008

AbstractChange blindness occurs when the presentation of successively presented pictures goes along with a simultaneous presentation of distractors (e.g., mudsplashes). An ERP component (N2pc) was used to track shifts of attention to lateralized changes under different attentional conditions. Observing central changes and not knowing about lateral changes elicited no N2pc. If lateral changes were task relevant, however, an N2pc was observed for both detected and undetected changes. Repeating the first task, lateral changes also evoked an N2pc, although they were again not task relevant. These results indicate that the transient of the change, although never occluded by mudsplashes, did not attract attention (bottom up) automatically but additional knowledge about its occurrence is necessary (top down). An attentional shift, however, does not necessarily lead to an aware representation of the change.
Locus of response slowing resulting from alternation‐based processing interference
Authors: Dudschig Carolin , Jentzsch Ines 
Published: July 2008

AbstractIn serial reaction time (RT) tasks, performance is strongly influenced by previous events. RT in Trial N is much slower after response changes than response repetitions from Trial N−2 to Trial N−1 when response–stimulus interval is short (I. Jentzsch & H. Leuthold, 2005). The aim of the present study was to investigate the mechanisms leading to this slowing by contrasting the idea of a hard bottleneck, postponing all subsequent processing, with a selective prolonging of postperceptual stages. We analyzed the lateralized readiness potential (LRP) and peak latencies of P1, N1, and P300 components in a choice RT task mapping four stimuli to two responses. Alternation‐based interference affected the S‐LRP interval but neither the LRP‐R interval nor the latency of P1, N1, and P300. These findings suggest that, whereas alternation‐based conflict originates at response‐related stages, postconflict slowing selectively affects central, premotoric processing.
Dialysis Rounds A Dialysis Case Presentation and Discussion Edited by Roger A. Rodby: Management of Refractory Ascites Using Nocturnal Home Hemodialysis
Authors: Pauly Robert P. , Sood Manish M. , Chan Christopher T. 
Published: July 2008

AbstractAscites in patients with end‐stage renal disease (ESRD) poses a challenging management scenario for nephrologists. We present two patients with ascites refractory to treatment with standard outpatient hemodialysis which resolved upon the initiation of nocturnal home hemodialysis (NHD). NHD is a form of intensive renal replacement therapy whereby patients receive up to 8 hours of continuous hemodialysis and ultrafiltration, five to seven times per week. In both cases, the ascites resolved within weeks of changing hemodialysis modalities. NHD allowed a significant reduction in ultrafiltration rates, which likely underlies the procedural tolerability and contributed to the successful outcomes. This option could be considered in the management of the patient with ESRD and refractory ascites.
Editorial: Diet, Inflammation, and Chronic Kidney Disease: Getting to the Heart of the Matter
Authors: Neade Tina , Uribarri Jaime 
Published: July 2008

AbstractCardiovascular disease (CVD) remains a leading cause of death in patients with chronic kidney disease (CKD). CVD is now thought to result from the interplay of several factors including inflammation, oxidative stress and endothelial dysfunction. Advanced glycation end products (AGE) are known to be elevated in patients with CKD and these compounds possess these pro‐oxidant, pro‐inflammatory and anti‐endothelial properties. There has been a great deal of literature linking diet and inflammation, and recent work has shown the diet to be a significant contributor to the body’s AGE pool. We herein hypothesize that a diet high in AGE plays an important role in the initiation of chronic subclinical inflammation that seems to underlie the high prevalence of CVD in CKD patients. Herein we will briefly examine the evidence linking different components of diet with inflammation in CKD patients. We will then focus on the role of dietary AGEs in inflammation and potentially CVD in CKD, and in conclusion, we will propose dietary modifications as part of a multifactorial approach to ameliorate unhealthy lifestyles among CKD patients. The most important message is that simple changes in culinary technique rather than in the food nutrient composition may be the most important part of preventing CVD in this population.
EFFECTS OF NUTRIENT ENRICHMENT ON PRIMARY PRODUCTION AND BIOMASS OF SEDIMENT MICROALGAE IN A SUBTROPICAL SEAGRASS BED1
Authors: Bucolo Philip , Sullivan Michael J. , Zimba Paul V. 
Published: July 2008

Eutrophication of coastal waters often leads to excessive growth of microalgal epiphytes attached to seagrass leaves; however, the effect of increased nutrient levels on sediment microalgae has not been studied within seagrass communities. A slow‐release NPK Osmocote fertilizer was added to sediments within and outside beds of the shoal grass Halodule wrightii, in Big Lagoon, Perdido Key, Florida. Gross primary production (GPP) and biomass (HPLC photopigments) of sediment microalgae within and adjacent to fertilized and control H. wrightii beds were measured following two 4‐week enrichment periods during June and July 2004. There was no effect of position on sediment microalgal GPP or biomass in control and enriched plots. However, nutrient enrichment significantly increased GPP in both June and July. These results suggest that sediment microalgae could fill some of the void in primary production where seagrass beds disappear due to excessive nutrient enrichment. Sedimentary chl a (proxy of total microalgal biomass) significantly increased only during the June enrichment period, whereas fucoxanthin (proxy of total diatom biomass) was not increased by nutrient enrichment even though its concentration doubled in the enriched plots in June.
PREDATION BY THE TOXIC DINOFLAGELLATE DINOPHYSIS FORTII ON THE CILIATE MYRIONECTA RUBRA AND OBSERVATION OF SEQUESTRATION OF CILIATE CHLOROPLASTS1
Authors: Nagai Satoshi , Nitshitani Goh , Tomaru Yuji , Sakiyama Sanae , Kamiyama Takashi 
Published: July 2008

This is the first report of the propagation of the toxic dinoflagellate Dinophysis fortii Pavill. under laboratory conditions when fed on the marine ciliate Myrionecta rubra grown with the cryptophyte Teleaulax amphioxeia (W. Conrad) D. R. A. Hill. In contrast, reduced growth of D. fortii (max. of 3–4 divisions) and formation of small cells were observed in the absence of the ciliate or when provided with T. amphioxeia only as prey, showing that D. fortii cannot utilize T. amphioxeia as prey. In the TEM observation of D. fortii cells, which had fully fed on the ciliate prey, well‐developed chloroplasts (5–12 μm in length) were seen and three thylakoids were usually arranged in most of the chloroplasts observed, but chloroplasts having two thylakoids were sometimes confirmed. In cells starved for 4 weeks, decrease of chloroplast numbers and disappearance of large chloroplasts were observed, and only a few small chloroplasts (0.5–2 μm in length) remained in the marginal regions. In the observation of the sequestration process of the chloroplasts ingested from M. rubra by D. fortii, within 15 min after D. fortii captured M. rubra, incorporation of almost all of the chloroplasts was observed, while most of the other cell contents still remained in the M. rubra cell. After that, dispersion of the ingested chloroplasts toward the marginal regions was confirmed, suggesting that chloroplasts of M. rubra are ingested and dispersed in D. fortii cells in advance of the ingestion of the other cell contents to prevent them from being digested in food vacuoles. The ingested chloroplasts can also function as kleptoplastids.
CULTURE OF THE HETEROTROPHIC DINOFLAGELLATE PROTOPERIDINIUM CRASSIPES (DINOPHYCEAE) WITH NONCELLULAR FOOD ITEMS1
Authors: Yamaguchi Aika , Horiguchi Takeo 
Published: July 2008

The genus Protoperidinium is an assemblage of heterotrophic dinoflagellates, several species of which have been successfully cultured in the past using various photosynthetic algae as a food source. We succeeded in culturing Protoperidinium crassipes (Kof.) Balech on three separate occasions for periods ranging from 2 to 21 months using rice flour as a food source. In these cultures, unusual small types of cells that were never observed to actively feed sometimes appeared. We confirmed that P. crassipes in culture exhibited bioluminescence.