bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improving the Efficiency of the Nelson–Aalen Estimator: the Naive Local Constant Estimator
Authors: GUILLEN MONTSERRAT , NIELSEN JENS P. , PEREZ‐MARIN ANA M. 
Published: November 2006

Abstract.  The Nelson–Aalen estimator is well known to be an asymptotically efficient estimator of the cumulative hazard function, see Andersen et al. (Statistical models based on counting processes, Springer‐Verlag, New York, 1993) among many others. In this paper, we show that the efficiency of the Nelson–Aalen estimator can be considerably improved by using more information in the estimation process than the traditional Nelson–Aalen estimator uses. While our approach results in a biased estimator, the variance improvement is substantial. By optimizing the balance between the bias loss and the variance improvement, we obtain results on the efficiency gain. Several examples for known failure time distributions are used to illustrate these ideas.
Estimating The Variance of Estimated Trends in Proportions When There is No Unique Subject Identifier
Authors: Mountford William K. , Lipsitz Stuart R. , Fitzmaurice Garrett M. , Carter Rickey E. , Soule Jeremy B. , Colwell John A. , Lackland Daniel T. 
Published: November 2006

SummaryLongitudinal population-based surveys are widely used in the health sciences to study patterns of change over time. In many of these data sets unique patient identifiers are not publicly available, making it impossible to link the repeated measures from the same individual directly. This poses a statistical challenge for making inferences about time trends because repeated measures from the same individual are likely to be positively correlated, i.e., although the time trend that is estimated under the naïve assumption of independence is unbiased, an unbiased estimate of the variance cannot be obtained without knowledge of the subject identifiers linking repeated measures over time. We propose a simple method for obtaining a conservative estimate of variability for making inferences about trends in proportions over time, ensuring that the type I error is no greater than the specified level. The method proposed is illustrated by using longitudinal data on diabetes hospitalization proportions in South Carolina.
Evaluation of Statistical Protocols for Quality Control of Ecosystem Carbon Dioxide Fluxes
Authors: Perez-Quezada Jorge F. , Saliendra Nicanor Z. , Emmerich William E. , Laca Emilio A. 
Published: November 2006

SummaryThe process of quality control of micrometeorological and carbon dioxide (CO2) flux data can be subjective and may lack repeatability, which would undermine the results of many studies. Multivariate statistical methods and time series analysis were used together and independently to detect and replace outliers in CO2 flux data derived from a Bowen ratio energy balance system. The results were compared with those produced by five experts who applied the current and potentially subjective protocol. All protocols were tested on the same set of three 5-day periods, when measurements were conducted in an abandoned agricultural field. The concordance of the protocols was evaluated by using the experts’ opinion (mean ± 1.96 standard deviations) as a reference interval (the Bland–Altman method). Analysing the 15 days together, the statistical protocol that combined multivariate distance, multiple linear regression and time series analysis showed a concordance of 93% on a 20-min flux basis and 87% on a daily basis (only 2 days fell outside the reference interval), and the overall flux differed only by 1.7% (3.2 g CO2 m−2). An automated version of this or a similar statistical protocol could be used as a standard way of filling gaps and processing data from Bowen ratio energy balance and other techniques (e.g. eddy covariance). This would enforce objectivity in comparisons of CO2 flux data that are generated by different research groups and streamline the protocols for quality control.
Regulation of cognitive resources during sustained attention and working memory in 10‐year‐olds and adults
Authors: Karatekin Canan , Marcus David J. , Couperus Jane W. 
Published: November 2006

AbstractWe examined differences between 10‐year‐olds and young adults in resource recruitment and regulation during tasks of sustained attention and spatial working memory. We administered participants spatial 0‐ and 1‐back tasks and used pupillary dilation as a measure of resource recruitment. Repeated administration of 0‐back led to smaller pupillary dilations and greater response time (RT) variability, revealing a vigilance decrement. Effects of repeated administration of 0‐back and differences between 0‐ and 1‐back in d′ and RTs were similar between ages. Results further suggested that the children may not have been as effective as adults in extracting frequency information. Thus, on simple tasks of sustained attention and working memory, children recruit resources in a manner similar to adults. Finally, d′ was correlated with RT variability on both tasks at both ages, highlighting the role of attentional fluctuations on both tasks.
A new perspective on the effects of price promotions in Taiwan: a longitudinal study of a Chinese society
Authors: Shen Yung‐Cheng , Chi Chung‐Hsing , Chen Ja‐Shen 
Published: November 2006

AbstractThis study investigated the effects of price promotions on consumers’ brand affect. Given the inconsistent findings in previous research, it is proposed that the effects of price promotion depend on two moderator variables: brand image and consumer loyalty. For high loyalty consumers of a prestigious brand, price incentive incompatible with the brand image can hurt the brand affect. When a non‐prestigious brand is involved, brand affect is positively influenced. However, these effects are limited to high loyalty consumers only. There was no effect on low loyalty consumers. In a longitudinal study of the Taiwanese market using emails, these hypotheses were tested and supported.
If it is good for the child’s development then I say yes almost every time: how parents relate to their children’s consumption
Authors: Brusdal Ragnhild 
Published: November 2006

AbstractThe article looks into how parents see their children’s consumption. The data material consist of focus group interviews with parents and children living in relatively affluent Scandinavian society. The result shows that parents are not necessarily negative towards their children’s consumption, and in some fields they are willing to spend more than the children expect or want. Parents have two approaches towards their children’s consumption. The child perspective puts the child in the centre with the child’s need for development and protection. The consumer critical discourse dominates and children are seen as vulnerable. In many situations parents will stretch beyond the children’s expectations if they see the consumption as useful. In the parent’s perspective parental skills is exhibited. The parent’s economic status as well as their parental skills and competence are exhibited, and the child’s consumption demonstrates if you are caring and responsible parents.
JNK‐ and Rac1‐dependent induction of immediate early gene pip92 suppresses neuronal differentiation
Authors: Park Jung Bum , Kim Eun Joo , Yang Eun Jin , Seo Su Ryeon , Chung Kwang Chul 
Published: November 2006

AbstractThe immediate early gene pip92 is rapidly and transiently induced by serum, basic fibroblast growth factor (bFGF), nerve growth factor (NGF) and phobol ester, as well as various toxic stimuli. Rho GTPases, such as RhoA, Rac1 and Cdc42, have been implicated in both cytoskeletal rearrangement and cell cycle control. Rac1 and Cdc42 induce neurite outgrowth in many types of neuronal cells. A downstream effector of both Rac1 and Cdc42, p21‐activated kinase (Pak1), is highly enriched in neurons. In the present study, we examined the signal transduction pathways involved in pip92 induction, focusing on the involvement of Rho family guanosine 5′‐triphosphate (GTP)ases. We also examined the functional role of pip92 expression during FGF‐induced neuronal differentiation in embryonic hippocampal cells. Significant and robust activation of c‐Jun N‐terminal Kinase (JNK), Rac1 and extracellular signal‐regulated kinase (ERK) appeared to be important for pip92 induction in response to bFGF. Transient transfection of kinase‐inactive MEKK7 or chemical inhibitors of JNK significantly decreased the activation of Rac1 by FGF. However, blockade of Rac1 did not affect JNK activity. Moreover, a MEK‐ERK blockade did not affect Rac1 activity. Activation of JNK and Rac1 induced Pak1 activity, which could then phosphorylate and activate transcription factor Elk1. Stimulation of Pak1‐dependent Elk1 was required for the bFGF‐induced activation of pip92. Suppression of endogenous pip92 expression by siRNA significantly enhanced bFGF‐induced neurite outgrowth, while the ectopic expression of pip92 suppressed the neurite extension. Taken together, these data suggest that neurogenic growth factor‐induced expression of pip92 is critical for the regulation of neuronal differentiation, occurring through the subsequent activation of Rac1, JNK, Pak1 and Elk1.
Isolation and characterization of eight polymorphic microsatellite markers in Aphanius fasciatus (Teleostei: Cyprinodontidae)
Authors: BABBUCCI MASSIMILIANO , PAPPALARDO ANNA MARIA , FERRITO VENERA , BARBISAN FEDERICA , PATARNELLO TOMASO , TIGANO CONCETTA 
Published: November 2006

AbstractThe first set of eight polymorphic microsatellites markers was successfully optimized from a partial genomic library enriched for an AC motif of the killifish Aphanius fasciatus Nardo, 1827 (Teleostei, Cyprinodontidae), a brackish‐water fish widely distributed along the coasts of the Mediterranean Sea. The developed loci proved to be polymorphic, displaying from two to six alleles per locus with expected heterozygosity ranging from 0.277 to 0.752. All loci were under Hardy–Weinberg equilibrium, except Af8 that showed significant heterozygotes deficiency, and there was no evidence of linkage associations between any pair of loci. Markers reported here will be potentially useful in monitoring of genetic population structure in this species.
Isolation and characterization of 11 polymorphic microsatellite markers for the marine gastropod Concholepas concholepas (Brugière, 1789)
Authors: CÁRDENAS LEYLA , DAGUIN CLAIRE , CASTILLA JUAN CARLOS , VIARD FRÉDÉRIQUE 
Published: November 2006

AbstractBecause of its long‐lived planktonic stage, the marine gastropod Concholepas concholepas is expected to exchange larvae over large distances. However, discrepancies between expected and realized dispersal have been documented in marine invertebrates. To investigate relationships between potential and effective (i.e. gene flow) dispersal, we developed 11 microsatellite markers and investigate their usefulness by analysing two populations distant by c. 4000 km. The 11 loci were found to be highly polymorphic in both populations, with 12–51 alleles according to the locus. This polymorphism is strong enough to allow fine‐scale population analyses including larval studies and paternity analyses.
Multimorbidity and Survival in Older Persons with Colorectal Cancer
Authors: Gross Cary P. , Guo Zhenchao , McAvay Gail J. , Allore Heather G. , Young Mary , Tinetti Mary E. 
Published: November 2006

OBJECTIVES: To ascertain the effect of common chronic conditions on mortality in older persons with colorectal cancer.DESIGN: Retrospective cohort study.SETTING: Population‐based cancer registry.PARTICIPANTS: Patients in the Surveillance Epidemiology and End Results–Medicare linked database who were aged 67 and older and had a primary diagnosis of Stage 1 to 3 colorectal cancer during 1993 through 1999.MEASUREMENTS: Chronic conditions were identified using claims data, and vital status was determined from the Medicare enrollment files. After estimating the adjusted hazard ratios for mortality associated with each condition using a Cox model, the population attributable risk (PAR) was calculated for the full sample and by age subgroup.RESULTS: The study sample consisted of 29,733 patients, 88% of whom were white and 55% were female. Approximately 9% of deaths were attributable to congestive heart failure (CHF; PAR =9.4%, 95% confidence interval (CI) =8.4–10.5%), more than 5% were attributable to chronic obstructive pulmonary disease (COPD; PAR =5.3%, 95% CI=4.7–6.6%), and nearly 4% were attributable to diabetes mellitus (PAR =3.9%, 95% CI=3.1–4.8%). The PAR associated with CHF increased with age, from 6.3% (95% CI=4.4–8.8%) in patients aged 67 to 70 to 14.5% (95% CI=12.0–17.5%) in patients aged 81 to 85. Multiple conditions were common. More than half of the patients who had CHF also had diabetes mellitus or COPD. The PAR associated with CHF alone (4.29%, 95% CI=3.68–4.94%) was similar to the PAR for CHF in combination with diabetes mellitus (3.08, 95% CI=2.60–3.61%) or COPD (3.93, 95% CI=3.41–4.54%).CONCLUSION: A substantial proportion of deaths in older persons with colorectal cancer can be attributed to CHF, diabetes mellitus, and COPD. Multimorbidity is common and exerts a substantial effect on colorectal cancer survival.
Management of Noncancer Pain in Community‐Dwelling Persons with Dementia
Authors: Shega Joseph W. , Hougham Gavin W. , Stocking Carol B. , Cox‐Hayley Deon , Sachs Greg A. 
Published: November 2006

OBJECTIVES: To explore the pharmacological treatment of noncancer pain in persons with dementia and identify predictors associated with insufficient analgesia.DESIGN: Cross‐sectional analysis of an observational cohort study.SETTING: Academic outpatient geriatric clinic in Chicago, Illinois.PARTICIPANTS: A total of 115 dyads, mostly African American, consisting of community‐dwelling persons with dementia and their caregivers.MEASUREMENTS: Patient report of demographics, noncancer pain, function, cognition, and depression. Caregiver report of patient agitation and over‐the‐counter and prescription medications.RESULTS: Sixty‐two of 115 (54%) patients reported pain “on an average day.” The caregivers of more than half of persons with dementia who reported pain “on an average day” did not report analgesic use. The majority of caregivers who reported analgesic use reported that patients took a World Health Organization Class I medication. No patients had been prescribed a Class III (strong opioid) drug. Fifty‐three of 115 (46%) patients had potentially insufficient analgesia. In the logistic regression, insufficient analgesia was associated with greater age, Mini‐Mental State Examination score of less than 10, and impairment in daily functioning. Insufficient analgesia was 1.07 times as likely (95% confidence interval (CI)=1.01–1.14) for each additional year of age, 3.0 times as likely (95% CI=1.05–9.10) if the subject had advanced dementia, and 2.5 times as likely (95% CI=1.01–6.25) if the patient had any impairment in activities of daily living.CONCLUSION: In this convenience sample from a geriatric clinic, many persons with dementia and noncancer pain were not receiving pharmacological treatment. Those at greatest risk for insufficient analgesia were older, had moderate to severe dementia, and experienced impairments in activities of daily living.
Isolated Urinary, Fecal, and Double Incontinence: Prevalence and Degree of Soiling in Stroke Survivors
Authors: Brittain Katherine , Perry Sarah , Shaw Chris , Matthews Ruth , Jagger Carol , Potter John 
Published: November 2006

OBJECTIVES: To investigate the prevalence of isolated urinary and fecal incontinence and double incontinence in community‐living stroke survivors and to assess the degree of soiling.DESIGN: Community‐based postal survey.SETTING: Leicestershire, United Kingdom.PARTICIPANTS: Sixty‐four thousand seven hundred forty‐nine community‐dwelling residents (aged≥40) were randomly selected from the Leicestershire Health Authority register. Residents living in institutional settings were excluded.MEASUREMENTS: Respondents were asked about previous stroke, urinary and bowel symptoms, and general health and demographic details including age, sex, and ethnicity. Urinary incontinence was defined as leakage several times a month or more often. Major fecal incontinence was defined as soiling of underwear, outer clothing, furnishings, or bedding several times a month or more often.RESULTS: A 65% response rate to the postal survey was obtained, with the return of 39,519 eligible questionnaires; 4% (n=1,483) reported stroke. Five percent of stroke survivors reported major fecal incontinence, with 4.3% reporting fecal and urinary incontinence and 0.8% reporting isolated fecal incontinence. Major fecal incontinence was four and a half times as prevalent in stroke survivors as in the nonstroke population, and stroke survivors were also twice as likely to report soiling of furnishings or bedding. Functional limitations influence the presence of fecal incontinence in the stroke and nonstroke population.CONCLUSION: Fecal incontinence is common in stroke survivors, and the degree of soiling can be considerable. Future research needs to explore the effect fecal incontinence can have on the lives of stroke survivors and on how it can best be managed in those living in the community.
Sensitivity of hepatitis B virus DNA transcription‐mediated amplification testing in hepatitis B surface antigen–positive blood donations
Authors: Bouchardeau Françoise , Girault Annie , Razer Annie , Servant‐Delmas Annabelle , Mercier Mélanie , Laperche Syria 
Published: November 2006

BACKGROUND: The objective was to evaluate the performance of nucleic acid testing (NAT) in the detection of hepatitis B virus (HBV) infection in hepatitis B surface antigen (HBsAg)‐positive blood donations.STUDY DESIGN AND METHODS: A total of 253 HBsAg‐ and anti‐hepatitis B core antigen (HBc)‐positive samples (50 hepatitis B e antigen [HBeAg]‐positive and 203 anti‐HBe–positive) from blood donations collected in France were studied. The samples were investigated with a blood screening assay (Procleix Ultrio, Chiron/Gen‐Probe) in minipool (MP; ×8) and in individual‐donation (ID) testing. All nonreactive samples were retested once, and nonreactive MP samples were assayed for viral load (VL).RESULTS: All 50 HBeAg‐positive samples were reactive in MP‐NAT and ID‐NAT. Of the 203 anti‐HBe–positive donations, 80.3 percent were MP‐ and ID‐reactive, 17.2 percent were MP‐nonreactive and ID‐reactive, and 2.5 percent were nonreactive in ID‐NAT. Overall the sensitivity of ID‐NAT was 98 percent versus 84 percent for MP‐NAT. After retesting, 16 of the 35 MP‐nonreactive and/or ID‐reactive donations became MP‐reactive and 2 of the ID‐nonreactive donations became NAT‐reactive. The capacity of Procleix Ultrio to detect HBV DNA was not related to HBsAg subtype, but correlated with the VL: the mean VL in the group of MP‐nonreactive samples was 1,420 copies per mL vs. 17,000 copies per mL in the group of 40 MP‐reactive samples.CONCLUSION: These results demonstrate that HBV‐NAT in ID format is far more effective in detecting viremia in chronic HBsAg carriers than in MP‐NAT. The sensitivity of the NAT assay needs to be improved to be considered for replacing the current HBsAg assays, especially when anti‐HBc testing is not performed.
A novel source of viable peripheral blood mononuclear cells from leukoreduction system chambers
Authors: Dietz Allan B. , Bulur Peggy A. , Emery Richard L. , Winters Jeffrey L. , Epps Dennis E. , Zubair Abba C. , Vuk‐Pavlović Stanimir 
Published: November 2006

BACKGROUND: Buffy coats are becoming less available as a source of research‐grade peripheral blood mononuclear cells (PBMNCs). Therefore, alternative sources of these cells were investigated.STUDY DESIGN AND METHODS: PBMNCs isolated from the cells retained in leukoreduction system chambers (LRSCs) and those eluted from white blood cell filters were compared. From LRSCs (1.88 ± 0.40) × 109 PBMNCs (n = 13) versus (0.43 ± 0.15) × 109 PBMNCs were isolated from leukofilter eluates (LFEs, n = 8; p < 0.0001).RESULTS: Cells from LRSCs and LFEs produced similar numbers of burst‐forming unit–erythroid, colony‐forming unit (CFU)–granulocyte‐macrophage, and CFU–granulocyte‐erythrocyte‐monocyte‐macrophage‐megakaryocyte colonies. The percentages of cells positive for CD3, CD4, CD8, CD14, CD19, and CD56 in the PBMNCs isolated from LRSCs and LFEs were indistinguishable. Cells isolated from LRSCs expressed higher levels of CD69 and CD25 in reaction to staphylococcal enterotoxin B than the cells isolated from LFEs. The source of cells affected neither the yield and purity of immunomagnetically isolated CD3+ cells, CD14+ cells, and CD56+ cells nor the function of T cells, natural killer cells, and in vitro matured dendritic cells (DCs). DC yield from LRSC‐derived CD14+ cells, however, was higher.CONCLUSION: LRSCs are a novel source of fully functional PBMNCs that can replace the more traditional sources of research‐grade cellular products.
Identification of six new alleles at theFUT1andFUT2loci in ethnically diverse individuals with Bombay and Para‐Bombay phenotypes
Authors: Storry Jill R. , Johannesson Jannica S. , Poole Joyce , Strindberg Johanna , Rodrigues Maria J. , Yahalom Vered , Levene Cyril , Fujita Claudia , Castilho Lilian , Hustinx Hein , Olsson Martin L. 
Published: November 2006

BACKGROUND:The Bombay and para‐Bombay phenotypes arise from mutations of theFUT1gene that silence the gene or affect the efficiency of the encoded 2‐α‐fucosyltransferase. Samples from seven individuals of different geographic backgrounds whose red blood cells had an apparent Bombay or para‐Bombay phenotype were investigated. Among these, novelFUT1andFUT2alleles were identified.STUDY DESIGN AND METHODS:Standard serologic techniques were used. Genomic DNA was sequenced with primers that amplified the coding sequence ofFUT1and the related secretor gene,FUT2. RoutineABOgenotyping analysis was performed.RESULTS:Five newFUT1alleles were identified that silencedFUT1or weakened α2FucT1 activity. These were 35C>T, 269G>T (Ala11Val, Gly89Val); 421A>G (Trp140Stop); 538C>T, 1089T>G (Gln180Stop, Ala363Ala); 689A>C (Gln230Pro); and 917C>T (Thr305Ile). In addition, both homozygosity and heterozygosity for the previously reported mutation, 826C>T (Gln276Stop), were observed. Four of seven samples were homozygous for the silencing mutation 428A inFUT2. One newFUT2allele was identified: 278C>T, 357C>T (Ala93Val, Asn119Asn).CONCLUSIONS:These results add to the growing database of apparently sporadic and random mutations in theFUT1gene and confirm previous reports regarding the lack of ethnic bias. In contrast, our data reinforce the apparent maintenance of the common nonsecretorFUT2alleles in the population.