bluuebunny/crossref_metadata_2025 huggingface dataset:
Host and Microbiological Factors Related to Dental Caries Development
Authors: De Soet J.J. , van Gemert-Schriks M.C.M. , Laine M.L. , van Amerongen W.E. , Morré S.A. , van Winkelhoff A.J.
Published: August 2008

Studies on dental caries suggest that in severe cases it may induce a systemic immune response. This occurs particularly when caries progresses into pulpal inflammation and results in abscess or fistula formation (AFF). We hypothesized that severe dental caries will affect the general health of children. The acute phase proteins alpha-1-acid glycoprotein (AGP), C-reactive protein (CRP) and the cytokine neopterin were chosen as parameters to monitor general health. Also, a polymorphism in the bacterial ligand CD14 (-260) was studied to investigate the relationship between genotype sensitivity for bacterial infections and AFF. In Suriname, children aged 6 years were recruited and enrolled into a dental care scheme, randomly assigned to 4 groups with different treatment strategies and monitored longitudinally. 348 children were included in the present study. Blood and saliva samples were taken at baseline and 1 year, and concentrations of serum AGP, CRP, neopterin, salivary Streptococcus mutans and CD14-260 C>T polymorphism were determined. There was no significant association between different treatment strategies and the serum parameters. Binary logistic regression analyses revealed a significant association between AFF as the outcome variable and the CD14 genotype and the concentrations of CRP and of neopterin as factors (p < 0.05). A significant negative association was found between the CD14-260 TT and AFF (p = 0.035, OR = 3.3) for the whole population. For children who had 4 or more carious lesions at baseline, the significance increased (p = 0.005, OR = 4.8), suggesting that the CD14-260 TT genotype was protective for AFF as a consequence of dental caries.
Phase II Trial of Neoadjuvant Cisplatin, 5-Fluorouracil and Interferon-Alpha in Operable Squamous Cell Carcinoma of the Esophagus
Authors: Bazarbashi Shouki , Abdelsalam Mahmoud , Amin Tarek , El-Bassiouni Mazen , Soudy Hussein , Elweshi Amr , Alhusseiny Hamed , Rehman Khaled , Memon Muhammed , Ajarim Dahish
Published: August 2008

Background: The combination of 5-fluorouracil (5-FU), cisplatin and interferon (IFN)-α was found to result in a high response rate in advanced esophageal squamous cell carcinoma (SCC). Methods: Resectable cases of esophageal SCC were treated with 3 cycles of chemotherapy consisting of cisplatin 70 mg/m2 i.v. on day 1, 5-FU 500 mg/m2/day i.v. as a continuous infusion on days 1–5 and IFN-α 4 million units/m2/day s.c. on days 1–5. Cycles were repeated every 21 days. Esophagectomy was performed 3–5 weeks after the 3rd cycle of chemotherapy. Results: Thirty patients were enrolled in the trial. Toxic death was observed in 1 patient because of esophageal perforation. Pathologically, complete response was observed in 4 of 23 patients who had esophagectomy. At a median follow-up period of 21.4 months, median progression-free survival was 11.5 months and median overall survival was 26.3 months. Conclusion: This regimen has substantial activity in localized SCC of the esophagus with encouraging survival duration.
Osteoblast Differentiation Stage-Specific Expression of the Pyrophosphate-Generating Enzyme PC-1
Authors: Hatch Nan E. , Franceschi Renny T.
Published: August 2008

Fibroblast growth factor (FGF) signaling plays a critical role in skeletal development, yet the mechanism by which FGFs affect bone mineralization is not well understood. Review of the literature investigating effects of FGF signaling on bone mineralization indicates that FGFs may stimulate expression of factors that prevent mineralization in the short term and enhance mineralization in the long term. Pyrophosphate is an ideal example of a factor that, dependent upon environment, has the capacity to inhibit or enhance mineralization. PC-1 is the primary generator of pyrophosphate in osteoblastic cells; therefore, regulated expression of PC-1 by FGFs may be a principal mechanism by which FGF signaling affects bone mineralization. We previously showed that FGF2 induces PC-1 expression in preosteoblastic cells and that this induction is differentiation stage dependent. In order to more directly investigate the mechanism by which PC-1 expression is regulated, we have cloned a 2.8-kb region of the PC-1 gene promoter and constructed a PC-1 gene promoter/firefly luciferase reporter construct. Results indicate that this construct is specifically responsive to FGF2 or ascorbate (an inducer of osteoblast differentiation). Promoter responsiveness to FGF2 is significantly diminished upon osteoblast differentiation, and increases in promoter activity that occur with osteoblast differentiation are inhibited by FGF2 treatment. These results indicate that the mechanism of PC-1 induction by FGF2 in preosteoblastic cells is distinct from the mechanism of induction that occurs with osteoblast differentiation. These results also indicate that PC-1 may play multiple and distinct roles in the development of mineralized tissues.
The Leucine-Rich Amelogenin Peptide Alters the Amelogenin Null Enamel Phenotype
Authors: Gibson Carolyn W. , Li Yong , Daly Bill , Suggs Cynthia , Yuan Zhi-an , Fong Hanson , Simmons Darrin , Aragon Melissa , Kulkarni Ashok B. , Wright J. Timothy
Published: August 2008

Introduction: The amelogenin proteins secreted by ameloblasts during dental enamel development are required for normal enamel structure. Amelx null (KO) mice have hypoplastic, disorganized enamel similar to that of human patients with mutations in the AMELX gene, and provide a model system for studies of the enamel defect amelogenesis imperfecta. Because many amelogenin proteins are present in developing enamel due to RNA alternative splicing and proteolytic processing, understanding the function of individual amelogenins has been challenging. Purpose: Our objective was to better understand the role of LRAP, a 59 amino acid leucine-rich amelogenin peptide, in the development of enamel. Approach: Teeth from transgenic mice that express LRAP under control of the Amelx regulatory regions were analyzed for mechanical properties, and transgenic males were mated with female KO mice. Male offspring with a null background that were transgene positive or transgene negative were compared to determine phenotypic differences using microcomputed tomography (microCT) and scanning electron microscopy (SEM). Results: Nanoindentation revealed no differences between LRAP transgenic and wild-type murine enamel. Using microCT, LRAPKO enamel volume and density measurements were similar to those from KO mice. However, in etched samples examined by SEM, the organization of the enamel rod pattern was altered by the presence of the LRAP transgene. Conclusions: The presence of LRAP leads to changes in enamel appearance compared to enamel from KO mice. Expression of a combination of amelogenin transgenes in KO mice may lead to rescue of the individual characteristics of normal enamel.
Short-Term Psychodynamic Psychotherapy and Fluoxetine in Major Depressive Disorder: A Randomized Comparative Study
Authors: Salminen Jouko K. , Karlsson Hasse , Hietala Jarmo , Kajander Jaana , Aalto Sargo , Markkula Juha , Rasi-Hakala Helena , Toikka Tuula
Published: August 2008

Background: There are few studies comparing the efficacy of short-term psychodynamic psychotherapy (STPP) and pharmacotherapy in major depressive disorder. We conducted a comparative study on the efficacy of STPP versus fluoxetine treatment in patients with major depressive disorder in a primary care setting. Methods: Fifty-one patients with major depressive disorder (DSM-IV) of mild or moderate severity were recruited through occupational health services providing primary health care. Patients were randomized to receive either STPP (1 session/week) or fluoxetine treatment (20–40 mg/day) for 16 weeks. The outcome measures included the Hamilton Depression Rating Scale (HDRS), the Beck Depression Inventory (BDI), and the Social and Occupational Functioning Assessment Scale (SOFAS). Results: Intent-to-treat analyses indicated that both treatments were highly effective in reducing the HDRS (p < 0.0001) and BDI (p < 0.0001) scores, as well as in improving functional ability (SOFAS; p < 0.0001), with no statistically significant differences between the treatments. Of those 40 subjects who completed the follow-up, 57% in the psychotherapy group and 68% in the fluoxetine group showed full remission (HDRS ≤7) after 4 months. Conclusions: Both STPP and pharmacological treatment with fluoxetine are effective in reducing symptoms and in improving functional ability of primary care patients with mild or moderate depression. This study suggests no marked differences in the therapeutic effects of these two treatment forms in a primary care setting.
Predictors of Premature Termination of Day Treatment for Personality Disorder
Authors: Ogrodniczuk John S. , Joyce Anthony S. , Lynd Larry D. , Piper William E. , Steinberg Paul I. , Richardson Kathryn
Published: August 2008

Background: Premature termination is a common problem in the treatment of personality disorder. Efforts to improve compliance should begin by recognising risk factors for premature termination. This prospective study identified predictors of premature termination from a day treatment program for personality disorder. Methods: Consecutively admitted patients with a personality disorder (n = 197) were assessed with self-report and interview measures. Patient personality characteristics were the primary predictors. Others were demographic, initial disturbance, and personality disorder variables. Cox proportional hazards regression was used. Results: Risk of terminating prematurely significantly increased if the patient had been previously hospitalised for psychiatric difficulties, was younger, had fewer prior contacts with health and social services, and had more severe borderline personality disorder traits. Conclusions: Information about which patients are at high risk for premature termination can help clinicians take measures to modify the risk. This might involve selection decisions, pre-treatment preparation, close monitoring during treatment, or addition of adjunctive interventions.
PFA-100 monitoring of von Willebrand factor (VWF) responses to desmopressin (DDAVP) and factor VIII/VWF concentrate substitution in von Willebrand disease type 1 and 2
Authors: van Vliet Huub H. D. M. , Kappers-Klunne Mies C. , Michiels Jan J. , Leebeek Frank W. G.
Published: August 2008

Dose-response relationship was studied between PFA-100 closure times (PFA CTs) and factor (F)VIII-von Willebrand factor (VWF) parameters in patients with von Willebrand disease (VWD) type 1 and type 2 before and after treatment with DDAVP (n=84) or FVIII/VWF concentrate (n=38). DDAVP treatment of patients with VWD type 1 normalised the PFA CTs by increasing VWF levels to normal. Of the 14 patients with VWD type 2, PFA CTs did not normalize in eight. Haemate-P substitution in patients with VWD type 1 induced a less favourable response as compared to DDAVP, because PFA CTs did not correct in all patients. Of 12 patients with VWD type 2 treated with Haemate-P, six showed a correction of PFA CTs (<250 sec), which correlated with the normalisation of the VWF CB/ Ag ratio. In-vitro studies were performed by using whole blood of patients with VWD and adding various amounts of FVIII/VWF concentrate. Addition of Haemate-P induced an increase of the VWF CB/Ag ratio from 0.30 to 0.70 in blood of patients with VWD type 2 with correction of the PFA CTs. Immunate did not result in an increase of VWF CB/Ag ratio in blood of VWD type 2 patients, and the PFA CTs remained prolonged. We conclude that PFA-100 might be an adequate instrument not only for diagnosis but also for monitoring of DDAVP responses and FVIII/ VWF substitution of patients with VWD type 1 and 2,but this is dependent upon the type of VWD and the concentrate used.
Population pharmacokinetics and pharmacodynamics of once and twice-daily rivaroxaban for the prevention of venous thromboembolism in patients undergoing total hip replacement
Authors: Borris Lars C. , Dahl Ola E. , Haas Sylvia , Huisman Menno V. , Kakkar Ajay K. , Kälebo Peter , Muelhofer Eva , Misselwitz Frank , Eriksson Bengt I. , Mueck Wolfgang
Published: August 2008

Rivaroxaban (Xarelto®) is an oral, direct factor Xa inhibitor in advanced clinical development for the prevention and treatment of thromboembolic disorders. The aim was to compare the population pharmacokinetics (PK) and pharmacodynamics (PD) of twice-daily (bid) and once-daily (od) rivaroxaban in patients undergoing total hip replacement (THR). Blood samples were collected from patients enrolled in two phase IIb, dose-ranging studies undertaken to investigate rivaroxaban for thromboprophylaxis after THR. A sparse sampling technique was used and the samples were pooled for PK and PD analysis, which used non-linear mixed effect modelling. Rivaroxaban PK (samples from 758 patients) were well described by an oral, one-compartment model; age and renal function influenced clearance, and body surface area affected volume of distribution. When comparing the same total daily doses, maximum plasma concentrations of rivaroxaban were higher and minimum plasma concentrations were lower with od dosing, compared with bid dosing; however, the 90% intervals overlapped. The area under the plasma concentration–time curve was 18–30% higher in the od than in the bid study. Prothrombin time in seconds (samples from 1181 patients) correlated with rivaroxaban plasma concentrations in a linear fashion in both studies. In conclusion, the PK and PD of rivaroxaban were predictable when given either bid or od. These findings, along with the suggested efficacy and safety of rivaroxaban in the phase II studies, relative to enoxaparin, supported the selection of a convenient, once-daily 10 mg rivaroxaban dose for investigation in phase III studies.
Clinical implications of aspirin resistance
Authors: Zimmermann Norbert , Hohlfeld Thomas
Published: August 2008

Aspirin reduces major atherothrombotic events across a wide spectrum of patients with atherosclerotic disease. The occurrence of ischemic events despite of aspirin treatment is a failure of therapy, often denoted ‘clinical aspirin resistance’. This is distinguished from laboratory assays showing an insufficient inhibition of platelet function, which indicate ‘laboratory aspirin resistance’. Laboratory aspirin resistance has been reported in up to 60% of patients after stroke or peripheral arterial disease, up to 70% in stable coronary heart disease and even up to 80% in acute myocardial infarction. However, this data must be interpreted carefully because of small sample sizes and potential confounding factors such as compliance, co-morbidities and large differences between the laboratory methods used for detection. During the past years, evidence has accumulated that laboratory aspirin resistance is associated with an increased incidence of major atherothrombotic events, with an up to 13-fold increased risk of events in patients with cardiovascular disease. Thus, an individualized antiplatelet therapy will have to consider the possibility of aspirin resistance, and the identification of aspirin non-responders may improve antiplatelet therapy in future. Whether an increased dose of aspirin or another antiplatelet drug (e.g. clopidogrel) instead or in addition to aspirin should be given is unclear. Prospective trials are underway which address this issue. This review gives an overview on the various clinical studies that have investigated the prevalence and clinical importance of laboratory aspirin resistance. Moreover, therapeutic options, as well as future perspectives are discussed.
Intermittent intravenous urokinase for critical limb ischemia in diabetic foot ulceration
Authors: Weck Matthias , Rietzsch Hannes , Lawall Holger , Pichlmeier Uwe , Bramlage Peter , Schellong Sebastian
Published: August 2008

Patients with diabetic foot ulceration and critical limb ischemia have a high risk of major amputation, especially if limbs can not be revascularized. Urokinase is effective in improving microcirculation in critical limb ischemia and might improve outcomes. There are no data on the efficacy and safety of urokinase treatment (survival free of major amputation, ulcer healing and the rate of minor and major bleeding). Therefore, we aimed to investigate the effect of urokinase treatment in a phase II clinical trial. We performed an open, prospective, non-controlled, multi-center phase II cohort study in 77 type-2 diabetic patients with critical limb ischemia and diabetic foot ulceration. Patients had no surgical or endovascular treatment option based on interdisciplinary consensus. Urokinase (1 Mio IU if plasma fibrinogen ≥2.5 g/l, 0.5 Mio IU if fibrinogen < 2.5 g/l) was administered for 21 days as an intravenous infusion over 30 minutes. Each patient was followed up for 12 months. Treatment for a median of 21 days resulted in 33% of patients being alive, having no major amputation and completely healed ulcers after 12 months. Total survival rate was 84.6%,amputation-free survival 69.2% and rate of major amputation 21.1%.Eighty-two percent of patients experienced at least once a complete ulcer healing within the course of study. Three serious adverse events were urokinase-related. Urokinase treatment in diabetic patients with critical limb ischemia appears to be effective, feasible and safe. Although this calls for a larger, randomized and controlled trial, the results are highly relevant for clinical practice to prevent these patients from receiving major amputation due to diabetic foot syndrome.

Clinical Trial Registration No.: NCT00537498
Should female relatives of factor V Leiden carriers be screened prior to oral contraceptive use?
Authors: Smith Kenneth J. , Monsef Brenna S. , Ragni Margaret V.
Published: August 2008

Venous thromboembolism (VTE) is three-fold higher among FV Leiden (FVL) carriers receiving oral contraceptives (OCPs) than in the general population. FVL screening, however, is not routinely performed before prescribing OCP, and the cost-effectiveness of this strategy is unknown. A decision tree model was constructed to evaluate FVL screening and prophylactic anticoagulation (AC) strategies in female relatives of FVL carriers. In the model, AC was low molecular weight heparin, given warfarin embryopathy risks. VTE morbidity, mortality, and other clinical parameters were obtained from published studies. Drug costs were based on average wholesale price, and counseling included VTE risk with OCP use and FVL status. Outcomes included medical costs, effectiveness measured as quality-adjusted-life-years (QALY), and the incremental cost-effectiveness ratio (ICER) over 30 years, with cost and effectiveness discounted at 3%/year. FVL screening and counselling without prophylactic AC cost less and was more effective than no screening in this population, but was less effective than screening, counselling,and prophylaxis during high-risk periods, which gained 0.083 QALY, for an ICER of $147/QALY gained. Screening with counselling and long-term AC cost $3,536 with minimal QALY gain and an ICER >$600,000/QALY. Screening, OCP counseling, and prophylactic AC during high-risk periods was favoured and cost <$20,000/QALY, unless: (a) high-risk prophylaxis cost >$4,231 (base $932), (b) long-term prophylaxis cost < $1199 (base $6,546), or (c)VTE relative risk reduction with prophylaxis was <21% (base 90%).In conclusion, screening, counselling and prophylactic AC during high-risk periods in female relatives of FVL carriers is an economically favourable strategy.
A multicenter evaluation of a new quantitative highly sensitive D-dimer assay for exclusion of venous thromboembolism
Authors: Palareti Gualtiero , Aguilar Carlos , Legnani Cristina , Reber Guido , Peetz Dirk , de Moerloose Philippe
Published: August 2008

D-dimer testing is widely applied for exclusion of deep-vein thrombosis (DVT) and pulmonary embolism (PE).We report on a multicenter performance evaluation of a new particle-enhanced immuno assay Innovance™ D-Dimer. Innovance D-Dimer assay was performed in 1,543 frozen samples from outpatients suspected of DVT and/or PE enrolled in three management studies as well as in a routine clinical practice. Samples were assayed on BCS®/BCS® XP, BCT® as well as Sysmex® CA-7000, CA-1500 and CA-560 analyzers (cut-off on all analyzers: 0.5 mg/l). Stratus® CS D-Dimer and Vidas® D-Dimer Exclusion were used for comparison. The precision study indicated total coefficients of variation ranging from 2.1% to 8.4% depending on the analyzer and on the sample. Sensitivity and negative predictive values were above 99% and their lower 95% confidence interval were equal or above 97.4% and 98.6%, respectively. Specificity ranged from 38.2% to 40.4% and the respective lower 95% confidence intervals from 35.5% to 37.7%. Area under the curve was 0.90 for all assay systems except for Innovance D-Dimer with BCT (0.89).Two samples from patients with distal DVT tested negative with all assay systems. One patient with high pre-test clinical probability and proximal DVT tested negative with Vidas D-Dimer Exclusion. Our data indicate that the performances of Innovance D-Dimer, regardless of the analyzer, are similar to the reference methods, and that this assay can be used for the exclusion of venous thromboembolic disease.
Procoagulant activities of plasma factor VIIc and factor Xc are positively and independently associated with concentrations of the high-density lipoprotein apolipoprotein, apo A-II
Authors: Atta Maria , Crook David , Shafique Faria , Johnston Desmond G. , Godsland Ian F.
Published: August 2008

The pro- and antiatherogenic roles of apolipoproteins B andA-I, respectively, are well-established although the importance of apolipoprotein A-II remains unclear. There is extensive evidence for the involvement of plasma lipoproteins in haemostatic function. However, in-vivo studies of relationships between haemostatic variables and apolipoprotein concentrations are very limited. Plasma fibrinogen, factors VIIc and Xc (FVIIc and FXc, respectively), apolipoproteins (apo) A-I, A-II and B, triglycerides, total, low-density and high-density lipoprotein (HDL) cholesterol, and cholesterol in HDL subfractions 2 and 3 were measured in 186 apparently healthy Caucasian men (aged 26–78 years; body mass index 19.9–37.8 kg/m2).Associations between haemostatic, apolipoprotein,lipid and lipoprotein variables were explored in uni- and multivariable analyses. Fibrinogen did not correlate with any of the lipid-related variables. FVIIc and FXc were significant positive univariate correlates of total cholesterol (correlation coefficients 0.26,p<0.001 and 0.19,p<0.05,respectively) triglycerides (0.37, p<0.001 and 0.36, p<0.001), and apoB (0.21, p<0.01 and 0.17, p<0.05) and apoA-II (0.19, p<0.05 and 0.29, p<0.001). HDL2 subfraction cholesterol correlated negatively with FVIIc and FXc (-0.20, p<0.01 and –0.22, p<0.01, respectively). In multivariable analysis, only the associations of FVIIc and FXc with total cholesterol, triglycerides and apoA-II remained statistically significant. In conclusion, total cholesterol and triglycerides were the major independent lipid correlates of FVIIc and FXc. The independent and positive associations of apoA-II with FVIIc and FXc suggest a prothrombotic involvement for this apolipoprotein
Proteasome degradation of protein C and plasmin inhibitor mutants
Authors: Nishio Miwako , Nakahara Masako , Egawa Nagisa , Hirosawa Shinsaku , Koyama Takatoshi
Published: August 2008

Protein C (PC) deficiency and plasmin inhibitor (PI) deficiency are inherited thrombotic and haemorrhagic disorders. We investigated the intracellular degradation of mutant proteins, using naturally occurring PC and PI mutants that lead to congenital deficiencies. To examine the necessity of N-linked glycosylation for the proteasomal degradation of PC and PI, PC178 and PC331 mutants treated with tunicamycin and N-glycosylation-lacking mutants, PC92Stop and PI-America were pulse chased. The analysis revealed that the speed of degradation of the tunicamycin-treated PC mutants, PC92Stop and PI-America lacking glycosylation, was slower than that of N-glycosylated mutants. Immunoprecipitation and immunoblot analysis showed that PC178 and PC331 mutants were associated with molecular chaperones, Bip, GRP94, and calreticulin. PI-America was associated with only Bip. Although degradation of mutants was mediated by proteasomes, no association with ubiquitin was detected. Co-transfection of endoplasmic reticulum (ER) degradation enhancing α-mannosidase-like protein (EDEM) accelerated the degradation of N-glycosylated PC. In the absence of autophagy using Atg5-deficient cell lines, the degradation of the PC331 mutant was mildly accelerated but that of PC178, PI-America and PI-Okinawa mutants was not influenced. While the degradation of the PC and PI mutants was facilitated by N-glycosylation moieties, they were ubiquitin-independently degraded by proteasomes, irrespective of the presence or absence of N-glycosylation. Molecular chaperone binding was influenced by the presence of N-glycosylation moieties. When the misfolded or truncated mutant proteins are functionally active, proteasome inhibitors such as bortezomib may have therapeutic potential for treatment of protein deficiencies.
The Effects of Accessory Stimuli on Information Processing: Evidence from Electrophysiology and a Diffusion Model Analysis
Authors: Jepma Marieke , Wagenmakers Eric-Jan , Band Guido P. H. , Nieuwenhuis Sander
Published: August 2008

People typically respond faster to a stimulus when it is accompanied by a task-irrelevant accessory stimulus presented in another perceptual modality. However, the mechanisms responsible for this accessory-stimulus effect are still poorly understood. We examined the effects of auditory accessory stimulation on the processing of visual stimuli using scalp electrophysiology (Experiment 1) and a diffusion model analysis (Experiment 2). In accordance with previous studies, lateralized readiness potentials indicated that accessory stimuli do not speed motor execution. Surface Laplacians over the motor cortex, however, revealed a bihemispheric increase in motor activation—an effect predicted by nonspecific arousal models. The diffusion model analysis suggested that accessory stimuli do not affect parameters of the decision process, but expedite only the nondecision component of information processing. Consequently, we conclude that accessory stimuli facilitate stimulus encoding. The visual P1 and N1 amplitudes on accessory-stimulus trials were modulated in a way that is consistent with multisensory energy integration, a possible mechanism for this facilitation.
Oscillatory Correlates of Retrieval-induced Forgetting in Recognition Memory
Authors: Spitzer Bernhard , Hanslmayr Simon , Opitz Bertram , Mecklinger Axel , Bäuml Karl-Heinz
Published: August 2008

Retrieval practice on a subset of previously studied material enhances later memory for practiced material but can inhibit memory for related unpracticed material. The present study examines the effects of prior retrieval practice on evoked (ERPs) and induced (oscillatory power) measures of electrophysiological activity underlying recognition of practiced and unpracticed words. Compared to control material, recognition of unpracticed words was characterized by reduced amplitudes of the P2 ERP component and by reduced early (200–400 msec) oscillatory theta power. The reduction in P2 amplitude was associated with decreased evoked theta power but not with decreased theta phase locking (phase-locking index). Recognition of unpracticed material was further accompanied by a reduction in occipital gamma power (>250 msec). In contrast, the beneficial effects of retrieval practice on practiced words were reflected by larger parietal ERP positivity (>500 msec) and by a stronger decrease in oscillatory alpha power in a relatively late time window (>700 msec). The results suggest that the beneficial and detrimental effects of retrieval practice are mediated by different processes. In particular, they suggest that reduced theta (4–7 Hz) and gamma (60–90 Hz) power reflect the specific effects of inhibitory processes on the unpracticed material's memory representation.
Experience-dependent Enhancement of Linguistic Pitch Representation in the Brainstem Is Not Specific to a Speech Context
Authors: Krishnan Ananthanarayan , Swaminathan Jayaganesh , Gandour Jackson T.
Published: August 2008

Neural representation of pitch is influenced by lifelong experiences with music and language at both cortical and subcortical levels of processing. The aim of this article is to determine whether neural plasticity for pitch representation at the level of the brainstem is dependent upon specific dimensions of pitch contours that commonly occur as part of a native listener's language experience. Brainstem frequency following responses (FFRs) were recorded from Chinese and English participants in response to four Mandarin tonal contours presented in a nonspeech context in the form of iterated rippled noise. Pitch strength (whole contour, 250 msec; 40-msec segments) and pitch-tracking accuracy (whole contour) were extracted from the FFRs using autocorrelation algorithms. Narrow band spectrograms were used to extract spectral information. Results showed that the Chinese group exhibits smoother pitch tracking than the English group in three out of the four tones. Moreover, cross-language comparisons of pitch strength of 40-msec segments revealed that the Chinese group exhibits more robust pitch representation of those segments containing rapidly changing pitch movements across all four tones. FFR spectral data were complementary showing that the Chinese group exhibits stronger representation of multiple pitch-relevant harmonics relative to the English group across all four tones. These findings support the view that at early preattentive stages of subcortical processing, neural mechanisms underlying pitch representation are shaped by particular dimensions of the auditory stream rather than speech per se. Adopting a temporal correlation analysis scheme for pitch encoding, we propose that long-term experience sharpens the tuning characteristics of neurons along the pitch axis with enhanced sensitivity to linguistically relevant variations in pitch.
Development of the Soil Moisture Index to Quantify Agricultural Drought and Its “User Friendliness” in Severity-Area-Duration Assessment
Authors: Sridhar Venkataramana , Hubbard Kenneth G. , You Jinsheng , Hunt Eric D.
Published: August 2008

This paper examines the role of soil moisture in quantifying drought through the development of a drought index using observed and modeled soil moisture. In Nebraska, rainfall is received primarily during the crop-growing season and the supply of moisture from the Gulf of Mexico determines if the impending crop year is either normal or anomalous and any deficit of rain leads to a lack of soil moisture storage. Using observed soil moisture from the Automated Weather Data Network (AWDN), the actual available water content for plants is calculated as the difference between observed or modeled soil moisture and wilting point, which is subsequently normalized with the site-specific, soil property–based, idealistic available water for plants that is calculated as the difference between field capacity and wilting point to derive the soil moisture index (SMI). This index is categorized into five classes from no drought to extreme drought to quantitatively assess drought in both space and time. Additionally, with the aid of an in-house hydrology model, soil moisture was simulated in order to compute model-based SMI and to compare the drought duration and severity for various sites. The results suggest that the soil moisture influence, a positive feedback process reported in many earlier studies, is unquestionably a quantitative indicator of drought. Also, the severity and duration of drought across Nebraska has a clear gradient from west to east, with the Panhandle region experiencing severe to extreme drought in the deeper soil layers for longer periods (>200 days), than the central and southwestern regions (125–150 days) or the eastern regions about 100 days or less. The anomalous rainfall years can eliminate the distinction among these regions with regard to their drought extent, severity, and persistence, thus making drought a more ubiquitous phenomenon, but the recovery from drought can be subject to similar gradations. The spatial SMI maps presented in this paper can be used with the Drought Monitor maps to assess the local drought conditions more effectively.
An Observational Analysis and Evaluation of Land Surface Model Accuracy in the Nebraska Sand Hills
Authors: Radell David B. , Rowe Clinton M.
Published: August 2008

In this study, the influence of subsurface water on the energy budget components of three locations with heterogeneous land surfaces in the Nebraska Sand Hills are examined through observations and use of the Noah land surface model (LSM). Observations of the four primary components of the surface energy budget are compared for a wet interdunal meadow valley, a dry interdunal valley, and a dunal upland location. With similar atmospheric forcing at each site, it was determined that differences in the partitioning of the mean diurnal net radiation (Rnet) existed among the three locations due to the influence of varied soil moisture and vegetation through the year. At the wet valley, observations indicated that almost 65% of the mean daily peak Rnet was used for latent heating, due to the relatively higher soil moisture content resulting from an annual upward gradient of subsurface water and denser vegetation. In sharp contrast, the dunal upland site yielded only 21% of the mean daily peak Rnet going to latent heating, and a greater mean diurnal soil heat flux with typically drier soils and sparser vegetation than at the wet valley. The dry valley partition of the peak Rnet fell between the wet valley and dunal upland site, with approximately 50% going to sensible heating and 50% toward latent heating. In addition to the observational analysis, an uncoupled land surface model was forced with the observations from each site to simulate the energy budgets, with no tuning of the model’s fundamental equations and with little adjustment of the model parameters to improve results. While the model was able to reasonably simulate the mean diurnal and annual energy budget components at all locations, in most instances with root-mean-square errors within 20%–25% of the observed values, the lack of explicit treatment of subsurface water within the model limited predictability, particularly at the wet valley site. For instance, only 25% of the peak mean diurnal Rnet went toward latent heating in the model simulation of the wet valley, compared to 65% as estimated by observations. Model evaluation statistics are presented to document the land surface model’s ability to capture the annual and mean diurnal variations in the surface energy budget terms at the dry valley and dunal upland sites, but the absence of subsurface water results in large errors in the wet valley simulation. From these results, a case is made for the future inclusion of the explicit treatment of subsurface water within the Noah LSM to better approximate the prediction of the surface energy budget in such environments.
The Role of Local Moisture Recycling Evaluated Using Stable Isotope Data from over the Middle of the Tibetan Plateau during the Monsoon Season
Authors: Kurita Naoyuki , Yamada Hiroyuki
Published: August 2008

Both meteorological data and stable isotope data were used to investigate the role that local moisture recycling plays in maintaining moist land surface conditions over the middle of the Tibetan Plateau during the summer monsoon season. Past studies have shown that precipitation events of the summer monsoon season can be categorized according to synoptic conditions as east-migrating trough types, heat low types, and regional circulation types. Precipitation events during an intensive observation period from 13 to 27 August 2004 were therefore classified into these three types. The contributions of locally recycled moisture in each precipitation type were investigated using isotopic features. The isotope data include precipitation, near-surface atmospheric moisture, and evapotranspiration. First, using a simple Rayleigh distillation model, the isotopic content of the moisture source of the rainfall was estimated from observed precipitation isotope data. The contribution of lower-atmospheric moisture to the precipitation was then evaluated by comparing isotopic values. Next, when rainfall was mainly fed by lower-atmosperic moisture, the contribution of evapotranspirated water in the lower atmosphere was assessed by considering the factors controlling the isotopic variability of lower-atmospheric moisture. The results show that, in the case of trough-type rainfall, moisture flux convergence occurred in this area and a remarkable increase in precipitable water was observed when a trough approached the site. Thus, observed large isotopic variation associated with the passage of a trough reflects the isotopic content of moisture advected from the surrounding areas. With the exception of trough-type rainfall, the simulated isotopic values agreed well with the isotopic value of lower-atmospheric moisture. This finding indicates that lower-atmospheric moisture is the dominant source of such rainfall. In these periods, temporal isotopic variation in lower-atmospheric moisture showed gradual increases accompanied by an increased contribution of evapotranspirated water that had relatively heavy isotopic values. In particular, when the regional circulation type of rainfall was observed, the local recycling ratio, which is the contribution of locally evapotranspirated water in the boundary layer, increased from 30% to 80%. Locally recycled moisture thus plays an important role in precipitation associated with regional circulation. Active moisture recycling contributes to a high frequency of precipitation events so that the moist land surface is maintained during the summer monsoon period in this region.
A Preliminary Analysis of Spatial Variability of Raindrop Size Distributions during Stratiform Rain Events
Authors: Lee Choong Ke , Lee Gyu Won , Zawadzki Isztar , Kim Kyung-Eak
Published: August 2008

The spatial variability of raindrop size distributions (DSDs) and precipitation fields is investigated utilizing disdrometric measurements from the four Precipitation Occurrence Sensor Systems (POSS) and radar reflectivity fields from S-band dual-polarization radar and vertically pointing X-band radar. The spatial cross correlation of the moments of DSDs, their ratio, error in rainfall estimate, and normalization parameters are quantified using a “noncentered” correlation function. The time-averaged spatial autocorrelation function of observed radar reflectivity factor (Ze) is smaller than that of estimated rainfall rate from Ze because of power-law R–Z transformation with its exponent larger than unity. The important spatial variability of DSDs and rain integral fields is revealed by the significant differences among average DSDs and leads to an average fractional error of 25% in estimating rainfall accumulation during an event. The spatial correlation of the reflectivity from POSS is larger than that of Ze because of larger measurement noise in Ze. The higher moments of DSDs are less correlated in space than lower moments. The correlation of rainfall estimate error is higher than that of estimated rainfall rate and of rainfall rate calculated from DSDs. The correlation of the characteristic number density is low (0.87 at 1.3-km distance), suggesting that the assumed homogeneity of the characteristic number density in space could result in larger errors in the retrieval of DSDs and rain-related parameters. However, the characteristic diameter is highly correlated in space.
On the Summertime Strengthening of the Northern Hemisphere Pacific Sea Level Pressure Anticyclone
Authors: Nigam Sumant , Chan Steven C.
Published: August 2008

This study revisits the question posed by Hoskins on why the Northern Hemisphere Pacific sea level pressure (SLP) anticyclone is strongest and maximally extended in summer when the Hadley cell descent in the northern subtropics is the weakest. The paradoxical evolution is revisited because anticyclone buildup to the majestic summer structure is gradual, spread evenly over the preceding 4–6 months, and not just confined to the monsoon-onset period, which is interesting, as monsoons are posited to be the cause of the summer vigor of the anticyclone.

Anticyclone buildup is moreover found focused in the extratropics, not the subtropics, where SLP seasonality is shown to be much weaker, generating a related paradox within the context of the Hadley cell’s striking seasonality. Showing this seasonality to arise from, and thus represent, remarkable descent variations in the Asian monsoon sector, but not over the central-eastern ocean basins, leads to the resolution of this paradox.

Evolution of other prominent anticyclones is analyzed to critique the development mechanisms: the Azores high evolves like the Pacific one, but without a monsoon to its immediate west. The Mascarene high evolves differently, peaking in austral winter. Monsoons are not implicated in both cases.

Diagnostic modeling of seasonal circulation development in the Pacific sector concludes this inquiry. Of the three forcing regions examined, the Pacific midlatitudes are found to be the most influential, accounting for over two-thirds of the winter-to-summer SLP development in the extratropics (6–8 hPa), with the bulk coming from the abatement of winter storm-track heating and transients. The Asian monsoon contribution (2–3 hPa) is dominant in the Pacific (and Atlantic) subtropics.

The modeling results resonate with observational findings and attest to the demise of winter storm tracks as the principal cause of the summer vigor of the Pacific anticyclone.
Intercomparison of Methods for the Temporal Interpolation of Synoptic Wind Fields
Authors: Gorman Richard M.
Published: August 2008

The problem of temporal interpolation of wind fields is addressed by comparing the performance of standard linear interpolation with two methods that aim to provide a more accurate description of advecting weather systems: the complex empirical orthogonal function (EOF) method introduced by Zavala-Hidalgo and a method based on fast Fourier transform (FFT) techniques. Two test cases are considered. In the first, wind fields representing an idealized fast-moving tropical cyclone were interpolated. In this case, the FFT method provided root-mean-square errors approximately two-thirds of those from linear interpolation, while the EOF method produced larger errors than linear interpolation. The second test case, using one month of ECMWF analysis fields on a Southern Hemisphere regional domain, showed that the FFT method is insufficiently robust for complex wind fields with multiple moving weather systems. The EOF method, on the other hand, produced smaller errors than linear interpolation.
Singular Vector Structure and Evolution of a Recurving Tropical Cyclone
Authors: Kim Hyun Mee , Jung Byoung-Joo
Published: August 2008

In this study, the structure and evolution of total energy singular vectors (SVs) of Typhoon Usagi (2007) are evaluated using the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) and its tangent linear and adjoint models with a Lanczos algorithm. Horizontal structures of the initial SVs following the tropical cyclone (TC) evolution suggest that, relatively far from the region of TC recurvature, SVs near the TC center have larger magnitudes than those in the midlatitude trough. The SVs in the midlatitude trough region become dominant as the TC passes by the region of recurvature. Increasing magnitude of the SVs over the midlatitude trough regions is associated with the extratropical transition of the TC. While the SV sensitivities near the TC center are mostly associated with warming in the midtroposphere and inflow toward the TC along the edge of the subtropical high, the SV sensitivities in the midlatitude are located under the upper trough with upshear-tilted structures and associated with strong baroclinicity and frontogenesis in the lower troposphere. Given the results in this study, sensitive regions for adaptive observations of TCs may be different following the TC development stage. Far from the TC recurvature, sensitive regions near TC center may be important. Closer to the TC recurvature, effects of the midlatitude trough become dominant and the vertical structures of the SVs in the midlatitude are basically similar to those of extratropical cyclones.
Baroclinic Transition of a Long-Lived Mesoscale Convective Vortex
Authors: Galarneau Thomas J. , Bosart Lance F. , Davis Christopher A. , McTaggart-Cowan Ron
Published: August 2008

The period 5–15 June 2003, during the field phase of the Bow Echo and Mesoscale Convective Vortex (MCV) Experiment (BAMEX), was noteworthy for the wide variety of mesoscale convective systems (MCSs) that occurred. Of particular interest was a long-lived MCV that formed in the trailing stratiform region of an MCS over west Texas at 0600 UTC 10 June. This MCV was noteworthy for its (i) longevity as it can be tracked from 0600 UTC 10 June to 1200 UTC 14 June, (ii) development of a surface cyclonic circulation and attendant −2- to −4-hPa sea level pressure perturbation, (iii) ability to retrigger convection and produce widespread rains over several diurnal heating cycles, and (iv) transition into a baroclinic surface cyclone with distinct frontal features. Baroclinic transition, defined here as the acquisition of surface fronts, occurred as the MCV interacted with a remnant cold front, left behind by a predecessor extratropical cyclone, over the Great Lakes region. Although the MCV developed well-defined frontal structure, which helped to focus heavy precipitation, weakening occurred throughout the baroclinic transition process. Energetics calculations indicated that weakening occurred as the diabatic and baroclinic energy conversion terms approached zero just prior and during baroclinic transition. This weakening can be attributed to (i) an increase in environmental wind shear, (ii) the development of a downshear tilt and associated anticyclonic vorticity advection over the surface low center, and (iii) the eastward relative movement of organized convection away from the MCV center.
An Examination of Perceived Corporate Citizenship, Job Applicant Attraction, and CSR Work Role Definition
Authors: Randy Evans W. , Davis Walter D.
Published: August 2008

Recent perspectives on corporate social responsibility (CSR) have called for increased research on how CSR affects individuals. Research is needed to examine whether individual differences affect the relationship between CSR and individual reactions to CSR. In response, this experimental study examined how perceptions of corporate citizenship influence job applicant attraction and work role definitions. Personal values and education concerning CSR are considered as interactive factors affecting the influence of perceptions of corporate citizenship. Results indicate that perceived corporate citizenship had a greater impact on job applicant attraction for those individuals who received prior education regarding CSR and for those who were higher in other-regarding value orientation. Furthermore, perceived corporate citizenship had a positive impact on the extent to which participants defined CSR as a personal work role responsibility. The authors also discuss the practical implications of these results for job applicant attraction and employee socialization.