bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of moisture on the dynamic mechanical relaxation of polyamide‐6/clay nanocomposites
Authors: Pramoda K. P. , Liu Tianxi
Published: April 2004

This article investigates the effect of moisture on the dynamic mechanical behavior of polyamide‐6 (PA6)/clay nanocomposites with dynamic mechanical analysis from −130 to 110 °C. The storage moduli increase with the clay loading for dried and moisture‐absorbed samples because of the enhancing effect from the high‐aspect‐ratio nanoclay. Storage moduli for moisture‐exposed samples are lower than those for dried samples; the longer the moisture absorption period is, the lower the moduli are for neat PA6 and PA6/clay nanocomposites. At temperatures below about 10 °C, however, samples exposed to moisture for longer periods tend to be stiffer than dried samples, probably because of the stiffening effect of ice. The peak temperature of the β relaxation shifts from −53 to −65 °C as the moisture content increases. The glass‐transition temperature (Tg) or α relaxation dramatically shifts; its position is significantly lowered from 62 to 17 °C as the moisture content increases (longer moisture absorption period) and from 62 to 50 °C as the clay loading increases. The observed depression of the storage modulus and Tg may be attributed to the plasticization effect of moisture absorption. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1823–1830, 2004
Dynamic light scattering and small‐angle neutron scattering studies on organogels formed with a gelator
Authors: Okabe Satoshi , Ando Keiichi , Hanabusa Kenji , Shibayama Mitsuhiro
Published: April 2004

Small‐angle neutron scattering (SANS) and light scattering studies were carried out on an organogel consisting of a gelator, coded P‐1, and dimethyl sulfoxide (DMSO). The gelator was made of an oligosiloxane stem and about eight branches of an amino acid derivative combined with a long alkyl chain. The amino acid part,N‐n‐pentanoyl‐L‐isoleucylaminooctadecane, was responsible for intermolecular association via hydrogen bonding between amide groups. After the complete dissolution of P‐1 in DMSO at 85 °C, the solution was cooled, and the variations of the scattered light intensity were monitored as a function of the temperature. The scattered intensity increased drastically at about 40 °C when the P‐1 concentration (C) was 3.5 g/L, and this indicated gel formation. The SANS results showed that the scattering intensity function was a monotonically decreasing function, regardless ofC. A master relationship of the scattering intensity was obtained with respect toC. These scattering studies disclosed the following facts. First, gelation could be monitored as an abrupt increase in the intensity. Second, the gel was composed of randomly oriented bundlelike clusters. Third, the structure factor could be reduced by the gelator concentration, and this indicated the presence of a self‐similar structure across the gelation threshold. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1841–1848, 2004
Sol–gel transition of methylcellulose in phosphate buffer saline solutions
Authors: Zheng Peijie , Li Lin , Hu Xiao , Zhao Xiongyan
Published: April 2004

The effect of phosphate buffer saline (PBS) on the thermoreversible sol–gel transition of methylcellulose has been systematically investigated with turbidimetric, microcalorimetric, and rheological methods. In the presence of PBS, the cloud points in the sol–gel transition and the clear points in the gel–sol transition shift to lower temperatures with increasing PBS content. This salting‐out effect is considered to be due to the competition between salts and methylcellulose for water molecules involved in the formation or destruction of cagelike water structures. The microcalorimetric studies prove that with increasing PBS content, the endothermic peak temperature decreases, whereas the enthalpy and entropy changes of the sol–gel transition increase. The rheological studies show that the addition of PBS favors the sol–gel transition, but the gel strength is almost independent of the PBS content, indicating an effect of adding salt equivalent to that of increasing the temperature. The results obtained from the rheological, microcalorimetric, and turbidimetric measurements are consistent. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1849–1860, 2004
Crystal structure of a protein associated with cell division from Mycoplasma pneumoniae (GI: 13508053): A novel fold with a conserved sequence motif
Authors: Chen Shengfeng , Jancrick Jaru , Yokota Hisao , Kim Rosalind , Kim Sung‐Hou
Published: April 2004

UPF0040 is a family of proteins implicated in a cellular function of bacteria cell division. There is no structure information available on protein of this family. We have determined the crystal structure of a protein from Mycoplasma pneumoniae that belongs to this family using X‐ray crystallography. Structural homology search reveals that this protein has a novel fold with no significant similarity to any proteins of known three‐dimensional structure. The crystal structures of the protein in three different crystal forms reveal that the protein exists as a ring of octamer. The conserved protein residues, including a highly conserved DXXXR motif, are examined on the basis of crystal structure. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Gas‐phase interaction between DNA and RNA bases and copper (II) ion: A density functional study
Authors: Marino T. , Toscano M. , Russo N. , Grand A.
Published: April 2004

This investigation, performed at Becke's three‐parameter functional with Perdew–Wang correlational functional/6‐311+G(2df,2p) level, can provide information about the geometry of all possible adducts originating from the interaction of Cu2+ cation with the most stable tautomers of DNA and RNA free bases. Several attachment sites for both purine and pyrimidine bases have been taken into account. Monocoordination or bicoordination has been observed in all the obtained complexes. The copper ion (II) has the major affinity for the most stable tautomer of guanine base. We have observed that an interesting behavior occurs when the copper ion interacts with the bases in an apical approach. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Theoretical study of possible ion‐molecule reactions leading to precursors of glycine in the interstellar medium
Authors: Largo Antonio , Redondo Pilar , Barrientos Carmen
Published: April 2004

Several ion‐molecule reactions that could lead to precursors of interstellar glycine have been theoretically studied. Predictions for their reaction enthalpies have been carried out at the B3LYP (Becke's three‐parameter exchange functional and the gradient‐corrected functional of Lee, Yang, and Parr) QCISD(T) (quadratic configuration interaction method with singles and doubles substitutions followed by a perturbative treatment of triple substitutions), and MP4 (fourth‐order Møller–Plesset perturbation theory including single, double, triple, and quadruple substitution) levels of theory. The reactions of protonated aminomethanol with formic acid and of HCO with methylamine are clearly endothermic and therefore not likely to be feasible under interstellar conditions. On the other hand, different reactions of cationic derivatives of ammonia with acetic acid or the reaction of CH3NH with formic acid are clearly exothermic. One of the most promising processes, based on its exothermicity (about 27 kcal/mol), is the reaction of NH with CH3COOH. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Effects of loop conformation on pKa and ligand binding in DNA gyrase B
Authors: Schechner Martina , Dejaegere Annick P. , Stote Roland H.
Published: April 2004

Molecular dynamics simulations of the adenosine triphosphatase (ATPase) subdomain of DNA gyrase B were done to characterize the flexibility of two loops implicated in ligand binding. The simulations show that bound adenosine triphosphate (ATP) stabilizes the conformation of the two loops. Simulations of the ATPase subdomain without ATP show that the loops are more flexible and can assume alternative conformations. We further investigated the dependence of histidine pKa on the loop conformations using continuum dielectric calculations. Using multiple conformations, we showed that the protonation states of titratable groups in the flexible loops can depend on the loop conformation. This, in turn, will affect ligand binding and calculations such as the multiple copy simultaneous search (MCSS) method for small functional group binding. This illustrates the importance of accurately determining the protonation state of the protein prior to the calculation. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
High‐level ab initio methods for calculation of potential energy surfaces of van der Waals complexes
Authors: Giese Timothy J. , York Darrin M.
Published: April 2004

A systematic series of highly correlated calculations of van der Waals potential energy surfaces (PESs) with large basis sets is presented. Reference data at the coupled‐cluster theory restricted to single, double, and noniterative triple excitations [CCSD(T)] level with large singly augmented correlation‐consistent basis functions, supplementary bond functions, and counterpoise corrections are provided. Results for minimum energy distances, well depths, vibrational frequencies, second virial coefficients, and Boyle temperatures are compared with corresponding experimental values. An extensive discussion of complete basis set extrapolation methods is presented. Here, the effect of extrapolation type, use of uncorrected and counterpoise‐corrected PESs, and direct property extrapolation are analyzed. Last, a new multicoefficient correlation method for van der Waals potential energy surfaces (MCCM‐vdW) is applied to three‐body interactions of helium trimers and to He … H2O interactions. Comparison with high‐level CCSD(T) calculations using large basis sets demonstrates that the MCCM‐vdW method is transferable to systems not considered in its parameterization. The method allows dispersion interactions of much larger systems to be studied reliably at a fraction of computational cost and offers a new tool for applications to rare‐gas clusters and the development of dispersion parameters for molecular simulation force fields. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Three validation metrics for automated probabilistic image segmentation of brain tumours
Authors: Zou Kelly H. , Wells William M. , Kikinis Ron , Warfield Simon K.
Published: April 2004

The validity of brain tumour segmentation is an important issue in image processing because it has a direct impact on surgical planning. We examined the segmentation accuracy based on three two‐sample validation metrics against the estimated composite latent gold standard, which was derived from several experts' manual segmentations by an EM algorithm. The distribution functions of the tumour and control pixel data were parametrically assumed to be a mixture of two beta distributions with different shape parameters. We estimated the corresponding receiver operating characteristic curve, Dice similarity coefficient, and mutual information, over all possible decision thresholds. Based on each validation metric, an optimal threshold was then computed via maximization. We illustrated these methods on MR imaging data from nine brain tumour cases of three different tumour types, each consisting of a large number of pixels. The automated segmentation yielded satisfactory accuracy with varied optimal thresholds. The performances of these validation metrics were also investigated via Monte Carlo simulation. Extensions of incorporating spatial correlation structures using a Markov random field model were considered. Copyright © 2004 John Wiley & Sons, Ltd.
Subject allocation and study curtailment for fixed event comparative poisson trials
Authors: Hoover Donald R.
Published: April 2004

Comparative Poisson trials of prophylactic interventions, such as vaccines, can be lengthy and costly. We evaluate two easily implemented approaches to reduce numbers of disease cases and person years of follow up (Nu+t) for comparative Poisson trials with fixed numbers of cases (T); (i) altering k the portion of Nu+t allocated to treatment and (ii) curtailed stopping before T cases if numbers of cases in the treatment or control group indicate that H0 has already been rejected or will not be rejected at T cases. Normal and arcsine approximations as well as discrete exact tests are evaluated. For studies not stopped early, allocating about ${1/(1+\sqrt r_a)}$ of person years to treatment roughly minimizes T needed for given size and power (where ra is the alternative hypothesized relative disease incidence in treated subjects used to power the study). This reduces T moderately vs equal allocation (k=0.5) by 2–3 cases in our examples with exact tests. However, the common practice of allocating k=0.5 of the person years to treatment may be the overall best strategy to minimize Nu+t for studies that are not stopped early. For studies analysed by exact test and planned with a one‐sided α ranging from 0.005 to 0.025, β from 0.1 to 0.2 and ra from 0.2 to 0.5, curtailed stopping reduces both the number of disease cases and Nu+t by 6–40 per cent depending on true treatment benefit. With curtailed stopping, allocating k=0.5 person years to treatment approximately minimizes the numbers of cases and person years under most conditions, although k as large as 0.6 often performs comparably well. If a specific localized k is selected to minimize disease cases for a study analysed by exact test, the study may be underpowered should the final allocation deviate even slightly from that k when it is conducted. Copyright © 2004 John Wiley & Sons, Ltd.
Eight interval estimators of a common rate ratio under stratified poisson sampling
Authors: Lui Kung‐Jong
Published: April 2004

Under the assumption that the rate ratio (RR) is constant across strata, we consider eight interval estimators of RR under stratified Poisson sampling: the weighted least‐squares (WLS) interval estimator with the logarithmic transformation, the interval estimator using the principle analogous to that of Fieller's Theorem, the interval estimators using Wald's statistic with and without the logarithmic transformation, the interval estimators using the Mantel–Haenszel statistic with and without the logarithmic transformation, the score test‐based interval estimator, and the asymptotic likelihood ratio test‐based interval estimator. We apply Monte Carlo simulation to evaluate and compare the performance of these estimators with respect to the coverage probability and the average length in a variety of situations. We find that the coverage probability of the commonly used WLS interval estimator tends to be smaller than the desired confidence level, especially when we have a large number of strata with a small expected total number of cases (ETNC) per stratum and the underlying RR is far away from 1 (i.e. RR18 or RR8). We further find that the two estimators with the logarithmic transformation, as well as the two test‐based estimators can consistently perform well in a variety of situations. When RR1 with a given reasonable size of ETNC per stratum, we note that the interval estimators without the logarithmic transformation can be preferable to the corresponding ones with the logarithmic transformation in the situations considered here. However, when evaluating the non‐coverage probability in the two tails, we find that the former tends to shift the left, while the latter is generally not subject to this concern. We also note that interval estimator using the Mantel–Haenszel (MH) statistic with the logarithmic transformation is likely less efficient than the two test‐based interval estimators using the score and the likelihood ratio tests. Finally, we use the data taken from a study of the postmenopausal hormone use on the risk of breast cancer in women as an example to illustrate the use of these interval estimators considered here. Copyright © 2004 John Wiley & Sons, Ltd.
Spatiotemporal pattern of calmodulin and [Ca2+]iis related to resumption of meiosis in mouse oocytes
Authors: Bi Chun‐Ming , Dai Gu , Chen Yan , Wu Yao‐Chun , Zhang Xi‐Ran , Li Chao‐Jun
Published: April 2004

During meiotic maturation, mammalian oocytes undergo a series of morphological and physiological changes that prepare them for fertilization. Calcium‐initiated signaling is thought to trigger these processes. In this study, we examine the spatio—temporal pattern of calcium and calmodulin (CaM), its downstream receptor, in order to investigate their association with meiotic maturation. Intracellular free calcium and activated CaM levels were measured using the fluorescent probes Calcium Green™‐1 and TA‐CaM, respectively. The distribution patterns were examined using confocal microscopy. Both calcium and activated CaM showed a dynamic spatiotemporal distribution during meiotic maturation. After release from IBMX buffer, calcium was found to periodically translocate from the perinuclear region to the germinal vesicle (GV) in 90 s intervals. After 90 min, calcium stopped oscillating and became concentrated within the GV. After a further 60 min, the GV broke down and calcium dispersed into the ooplasm, but calcium levels were slightly lower here than in the original nuclear region. Activated CaM also showed a dynamic patterning process similar to calcium. Taking the data from calcium chelation and CaM inhibition together, our results suggest that the dynamic distribution patterns of calcium and activated CaM are crucial for oocyte maturation.
Randomized double‐blind comparison of serotonergic (Citalopram) versus noradrenergic (Reboxetine) reuptake inhibitors in outpatients with somatoform, DSM‐IV‐TR pain disorder
Authors: Aragona Massimiliano , Bancheri Lara , Perinelli Donatella , Tarsitani Lorenzo , Pizzimenti Alessia , Conte Antonella , Inghilleri Maurizio
Published: April 2004

Objectives: Whether the effect of tricyclic antidepressants on Pain Disorder arises from their noradrenergic or serotonergic actions or both remains unclear. We compared the selective serotonin reuptake inhibitor (SSRI) citalopram and the noradrenergic reuptake inhibitor (NARI) reboxetine in outpatients with Pain Disorder. We also distinguished the drugs' analgesic and antidepressant effects.

Methods: In this 8‐week, randomized double‐blind study, 35 patients with a DSM‐IV‐TR diagnosis of Pain Disorder were randomly assigned to receive either citalopram 40 mg/day (N=17 patients) or reboxetine 8 mg/day (N=18). The Present Pain Intensity (PPI) scale and the Total Pain Rating Index (tPRI) of the McGill Pain Questionnaire were used to measure the effect on pain symptoms. Changes in the Zung Self‐Rating Depression Scale (Zung‐D) scores were evaluated to monitor a possible antidepressant effect. For all patients who had at least one assessment, an intent‐to‐treat analysis was performed.

Results: No significant differences were found in the demographic variables or clinical characteristics of the two treatment groups. In the citalopram group, PPI and tPRI scores measured at baseline decreased after treatment (tPRI: 41.9 vs. 30.0, p=.004; PPI: 3.5 vs. 2.8, p=.045) whereas in the reboxetine group differences were not statistically significant (tPRI: 35.2 vs. 31.5; PPI: 3.7 vs. 3.1). The Zung‐D showed no significant changes between baseline and endpoint assessment in either group.

Conclusions: Our study suggests that the SSRI citalopram may have a moderate analgesic effect in patients with Pain Disorder, and that this analgesic activity appears to be not correlated to changes in depressive scores. If confirmed in a larger sample, this evidence suggests that patients who are intolerant or resistant to tricyclic antidepressants, may be treated with SSRIs.
Enhanced Ras activity in pyramidal neurons induces cellular hypertrophy and changes in afferent and intrinsic connectivity in synRas mice
Authors: Gärtner Ulrich , Alpár Alán , Seeger Gudrun , Heumann Rolf , Arendt Thomas
Published: April 2004

Neurotrophic actions are critically controlled and transmitted to cellular responses by the small G protein Ras which is therefore essential for normal functioning and plasticity of the nervous system. The present study summarises findings of recent studies on morphological changes in the neocortex of synRas mice expressing Val12‐Ha‐Ras in vivo under the control of the rat synapsin I promoter. In the here reported model (introduced by Heumann et al. [J. Cell Biol. 151 (2000) 1537]), transgenic Val12‐Ha‐Ras expression is confined to the pyramidal cell population and starts postnatally at a time, when neurons are postmitotic and their developmental maturation has been basically completed. Expression of Val12‐Ha‐Ras results in a significant enlargement of pyramidal neurons. Size, complexity and spine density of dendritic trees are increased, which leads, finally, to cortical expansion. However, the main morphological design principles of ‘transgenic’ pyramidal cells remain preserved. In addition to somato‐dendritic changes, expression of Val12‐Ha‐Ras in pyramidal cells induces augmented axon calibres and upregulates the establishment of efferent boutons. Despite the enlargement of cortical size, the overall density of terminals representing intra‐ or interhemispheric, specific and non‐specific afferents is unchanged or even higher in transgenic mice suggesting a significant increase in the total afferent input to the neocortex. Although interneurons do not express the transgene and are therefore excluded from direct, intrinsic Val12‐Ha‐Ras effects, they respond with morphological adaptations to structural changes. Thus, dendritic arbours of interneurons are extended to follow the cortical expansion and basket cells establish a denser inhibitory innervation of ‘transgenic’ pyramidal cells perikarya.

It is concluded that expression of Val12‐Ha‐Ras in pyramidal neurons results in remodelling of neocortical structuring which strongly implicates a crucial involvement of Ras in cortical plasticity.
Holocene loess deposition and soil formation as competing processes, Matanuska Valley, Southern Alaska
Authors: Muhs Daniel R. , McGeehin John P. , Beann Jossh , Fisher Eric
Published: April 2004

Although loess–paleosol sequences are among the most important records of Quaternary climate change and past dust deposition cycles, few modern examples of such sedimentation systems have been studied. Stratigraphic studies and 22 new accelerator mass spectrometry radiocarbon ages from the Matanuska Valley in southern Alaska show that loess deposition there began sometime after ∼6500 14C yr B.P. and has continued to the present. The silts are produced through grinding by the Matanuska and Knik glaciers, deposited as outwash, entrained by strong winds, and redeposited as loess. Over a downwind distance of ∼40 km, loess thickness, sand content, and sand-plus-coarse-silt content decrease, whereas fine-silt content increases. Loess deposition was episodic, as shown by the presence of paleosols, at distances >10 km from the outwash plain loess source. Stratigraphic complexity is at a maximum (i.e. the greatest number of loesses and paleosols) at intermediate (10–25 km) distances from the loess source. Surface soils increase in degree of development with distance downwind from the source, where sedimentation rates are lower. Proximal soils are Entisols or Inceptisols, whereas distal soils are Spodosols. Ratios of mobile CaO, K2O, and Fe2O3 to immobile TiO2 show decreases in surface horizons with distance from the source. Thus, as in China, where loess deposition also takes place today, eolian sedimentation and soil formation are competing processes. Study of loess and paleosols in southern Alaska shows that particle size can vary over short distances, loess deposition can be episodic over limited time intervals, and soils developed in stabilized loess can show considerable variability under the same vegetation.
Risk factors for the development versus maintenance of posttraumatic stress disorder
Authors: Schnurr Paula P. , Lunney Carole A. , Sengupta Anjana
Published: April 2004

This study examined risk factors for posttraumatic stress disorder (PTSD) in Vietnam veterans: 68 women and 414 men of whom 88 were White, 63 Black, 80 Hispanic, 90 Native Hawaiian, and 93 Japanese American. Continuation ratio logistic regression was used to compare the predictive power of risk factors for (he development versus maintenance of full or partial PTSD. The development of PTSD was related to premilitary, military, and postmilitary factors. The maintenance of PTSD was related primarily to military and postmilitary factors. Multivariate analyses identified different models for development and maintenance. We conclude that development of PTSD is related to factors that occur before, during, and after a traumatic event, whereas failure to recover is related primarily to factors that occur during and after the event.
International publication trends in the traumatic stress literature
Authors: Bedard Michele , Greif Jennifer L. , Buckley Todd C.
Published: April 2004

This analysis looked at international publication trends in the field of trauma by examining first author affiliations of over 13,000 trauma publications from 1987 to 2001. Searches were conducted using the Published International Literature on Traumatic Stress (PILOTS) database to determine frequency of international contributions. A similar search of the Journal of Traumatic Stress (JTS) was also conducted. Although the majority of trauma research comes from investigators in North America, examining publication trends over time revealed that trauma research is becoming, increasingly international in its representation. Results suggest that of the overall trauma literature, 36% of contributions come from authors outside North America. Likewise, among JTS publications over the first 14 years of circulation, 27% came from authors outside North America. More recent publication years reflect higher levels of international contributions for both sources. The majority of trauma research published over the 15‐year span was in English. Implications for the field of traumatic stress research are discussed.
Social attitudes toward traumatized men and women: A vignette study
Authors: Mendelsohn Michaela , Sewell Kenneth W.
Published: April 2004

This study investigated social beliefs about gender‐appropriate reactions to trauma. Ninety‐three men and 179 women completed vignette measures of attitudes toward victims, the Bern Sex Role Inventory, and the Trauma History Questionnaire. Participants evaluated male victims less favorably than female victims. Women responded more positively toward all victims than men. Participants regarded female crime victims more positively than their male counterparts, but did not distinguish between male and female natural disaster victims. Feminine‐sex‐typed women rated victims more favorably than masculine‐sex‐typed individuals. There was a positive relation between personal trauma exposure and attitudes toward male victims among male participants. These findings contribute to an understanding of factors influencing the social reactions experienced by traumatized men and women, and have implications for clinical practice and psychoeducation.
Trauma exposure and retention in adolescent substance abuse treatment
Authors: Jaycox Lisa H. , Ebener Patricia , Damesek Leslie , Becker Kirsten
Published: April 2004

Trauma exposure and related symptoms interfere with adult adherence to drug treatment. Whether these findings hold true for adolescents is unknown. We examined trauma exposure. PTSD symptoms, and psychosocial functioning among 212 adolescents upon admission to long‐term residential drug treatment and examined retention in treatment at 6 months. Seventy‐one percent reported lifetime trauma exposure, and 29% of the trauma‐exposed met criteria for current PTSD. Trauma‐exposed adolescents reported more behavioral problems, with gender differences apparent. We divided the sample into three groups: no trauma exposure (21%), trauma‐exposed without PTSD (59%), and trauma‐exposed with PTSD (20%). Survival analysis showed that trauma‐exposed adolescents without PTSD left treatment sooner than the nonexposed. Need for attention to trauma in substance abuse treatment programs is discussed.
Bringing order out of chaos: A culturally competent approach to managing the problems of refugees and victims of organized violence
Authors: Eisenbruch Maurice , de Jong Joop T. V. M. , van de Put Willem
Published: April 2004

The collaborative program of the Transcultural Psychosocial Organization (TPO) provides a community‐oriented and culturally sensitive public health response to the psychosocial problems of refugees and victims of organized violence. This paper describes the 9‐step model that TPO has developed as a blueprint for each new intervention. Beneficiaries participate in determining priorities and there is an orientation toward culturally competent training, capacity‐building, and sustainability. Two cases, one related to Sudanese refugees in Uganda and the other to internally displaced persons and returnees in postwar Cambodia, show how the TPO intervention protocol is adapted to local settings. The paper provides preliminary evaluative comments on the model's performance.
Prevalence of posttraumatic stress disorder and comorbid depression in earthquake survivors in Turkey: An epidemiological study
Authors: Başoǧlu Metin , Kiliç Cengiz , Şalcioǧlu Ebru , Livanou Maria
Published: April 2004

This study examined the prevalence of posttraumatic stress disorder (PTSD) and depression 14 months after the earthquake in Turkey in 2 randomly selected samples from the epicenter (n = 530) and a suburb of Istanbul 100 km from the epicenter (n = 420). The rates of PTSD and depression comorbid with PTSD were, respectively, 23 and 16% at the epicenter and 14 and 8% in Istanbul. The strongest predictor of traumatic stress symptoms was fear during the earthquake, whereas predictions with female gender, past psychiatric illness, damage to home, participation in rescue work, past trauma, and loss of close ones were significant but weak. Our findings suggest that devastating earthquakes have long‐term psychological effects. Psychological interventions reducing fear may improve PTSD in survivors.
Treatment of posttraumatic stress disorder in postwar Kosovo high school students using mind–body skills groups: A pilot study
Authors: Gordon James S. , Staples Julie K. , Blyta Afrim , Bytyqi Murat
Published: April 2004

This preliminary study examined whether the practice of mind–body techniques decreases symptoms of posttraumatic stress in adolescents. Posttraumatic Stress Reaction Index questionnaires were collected from 139 high school students in Kosovo who participated in a 6‐week program that included meditation, biofeedback, drawings, autogenic training, guided imagery, genograms, movement, and breathing techniques. Three separate programs were held approximately 2 months apart. There was no control group. Posttraumatic stress scores significantly decreased after participation in the programs. These scores remained decreased in the 2 groups that participated in the follow‐up study when compared to pretest measures. These data indicate that mind–body skills groups were effective in reducing posttraumatic stress symptoms in war‐traumatized high school students.
Perceived social support and secondary traumatic stress symptoms in emergency responders
Authors: Hyman Ofra
Published: April 2004

This study investigated prevalence rates of secondary traumatic stress symptoms in Israeli Police forensic technicians, and the relationship between these symptoms and perceived social support as well as perceived severity of prior trauma (combat, work, personal). Ninety technicians from the Israeli Police Forensic Investigation Unit participated in the study. Intrusion and avoidance measured within the medium range of severity, whereas distress symptoms were below clinical threshold. Intrusion was significantly related to avoidance, distress, and the perceived severity of prior personal and work‐related exposure. No significant relationship was found between perceived social support and secondary traumatic stress symptoms. The data suggest that this cohort utilized avoidance effectively as a defense against intrusion.
Twenty‐four‐hour ambulatory assessment of heart rate and blood pressure in chronic PTSD and non‐PTSD veterans
Authors: Buckley Todd C. , Holohan Dana , Greif Jennifer L. , Bedard Michele , Suvak Michael
Published: April 2004

This study examined 24‐hr levels of ambulatory heart rate (HR) and blood pressure (BP) in 2 groups of male veterans: 19 with chronic posttraumatic stress disorder (PTSD) and 17 who never met criteria for PTSD. The relationships between diagnostic status, basal cardiovascular activity, and cardiovascular reactivity to stress were examined. Hierarchical linear modeling analyses revealed that the PTSD group had higher resting HR than the non‐PTSD group. Moreover, the PTSD group showed greater BP reactivity during times of affective distress than the non‐PTSD group. The health care implications of these findings are discussed, as are directions for future research.
Revictimization and interpersonal resource loss predicts PTSD among women in substance‐use treatment
Authors: Schumm Jeremiah A. , Hobfoll Stevan E. , Keogh Nancy Jones
Published: April 2004

Child physical abuse (CPA) and child sexual abuse (CSA) were hypothesized to be associated with revictimization and interpersonal resource loss in adulthood. These adulthood experiences were, in turn, hypothesized to increase risk for current posttraumatic stress disorder (PTSD). High‐risk women were recruited from an innercity drug and alcohol treatment center (N = 105). Interpersonal resource losses, partner‐produced physical assault, adulthood rape, CPA, and CSA had direct effects on PTSD. CPA and CSA also had indirect effects on PTSD through rape, which, in turn, predicted PTSD. Results suggest that the traumatic origins of current PTSD among substance‐using women are multifaceted and support the importance of considering interpersonal coping resources in evaluating and treating female substance users.
Acoustic monitoring of sediment‐pore fluid interaction
Authors: Li Xun , Pyrak‐Nolte Laura J.
Published: April 2004

Acoustic and chemical measurements were made on water‐saturated synthetic sediments undergoing diagenesis from uncompacted glass beads into a cemented glass bead, sandstone‐like material. The sediment‐water interaction was investigated as a function of time by monitoring the acoustic properties, water electrical conductivity, pH, and ion concentration. A reduction in the transmitted acoustic wave amplitude was correlated with a decrease in the total number of ions in the pore water. The lowest acoustic wave amplitude occurred when the ionic strength in the pore water had reached a minimum value. Calculation of the electrostatic potential showed that the force of repulsion between beads was strongest when the acoustic wave amplitude was at its minimum and the double layer electrostatic interaction potential between the beads was at a maximum value. At longer times the acoustic wave velocity of the transmitted wave increased as the cementation progressed. These results suggest that the chemical interaction between the pore fluid and grain alters the strength or stiffness of grain‐to‐grain contacts, which in turn alters the elastic modulus of the sediment frame. The important implications of this work are the potential use of acoustic or seismic techniques to monitor ion exchange between pore‐fluids and sediments in‐situ.
Microscopic analysis of imbibition processes in oolitic limestone
Authors: Roels Staf , Carmeliet Jan , Hens Hugo , Elsen Jan
Published: April 2004

Measurements of density, porosity, capillary moisture content and water absorption coefficients of Savonnières, a French layered limestone, show a wide variability on the local scale. The differences in imbibition properties can be explained by the microstructural variability as shown by optical microscopy. Microscopic investigations of free uptake experiments using a colored low‐viscous epoxy resin confirm the strong relations between imbibition and microstructure.
Water masses and circulation in the surface layers of the Caribbean at 66°W
Authors: Hernández‐Guerra Alonso , Joyce Terrence M.
Published: April 2004

A meridional hydrographic section was made in August–September 1997 at 66°W from the coast of Venezuela to Woods Hole aboard the R/V Knorr. In this report, we concentrate on near surface measurements in the Caribbean. The data show two distinct water masses with different origins. From approximately 14°N to Puerto Rico, Caribbean Surface Water and Subtropical Under Water with their source in the North Atlantic are found, as previously observed. From Venezuela to approximately 13°N, a less saline water mass with its source in the Tropics and South Atlantic is found. Within the southern portion of the section, two different velocity patterns are observed, namely, an eastward flow with a subsurface maximum near the coast of Venezuela, and a surface intensified westward jet with Velocities of 130 cm s−1 in midbasin.
Stable carbon isotopes in scots pine tree rings preserve a record of flow of the river Ob
Authors: Waterhouse J. S. , Barker A. C. , Carter A. H. C. , Agafonov L. I. , Loader N. J.
Published: April 2004

Annual values of carbon isotope ratios for the period 1898–1990 are reported for Scots pine (Pinus sylvestris) growing in the valley of the lower river Ob in western Siberia. The data show highly significant inverse correlation to river flow over the period of instrumental records (1934–1990), although the strength of the relationship shows some dependence on the distance of the tree from the edge of the river. The predictive power of a linear regression model derived from the second half of the data set is validated by comparing the river flow for the first half of the period with values predicted by the model. Agreement is highly significant (r=0.80, P<0.001). The results demonstrate the potential of carbon isotope ratios to predict river flow in this region.
Global warming: Evidence from satellite observations
Authors: Prabhakara C. , Iacovazzi R. , Yoo J.‐M. , Dalu G.
Published: April 2004

Observations made in Channel 2 (53.74 GHz) of the Microwave Sounding Unit (MSU) radiometer, flown on‐board sequential, sun‐synchronous, polar‐orbiting NOAA operational satellites, indicate that the mean temperature of the atmosphere over the globe increased during the period 1980 to 1999. In this study, we have minimized systematic errors in the time series introduced by satellite orbital drift in an objective manner. This is done with the help of the onboard warm‐blackbody temperature, which is used in the calibration of the MSU radiometer. The corrected MSU Channel 2 observations of the NOAA satellite series reveal that the vertically‐weighted global‐mean temperature of the atmosphere, with a peak weight near the mid troposphere, warmed at the rate of 0.13±0.05 Kdecade−1 during 1980 to 1999. The global warming deduced from conventional meteorological data that have been corrected for urbanization effects agrees reasonably with this satellite‐deduced result.
Regional climatic effects of anthropogenic aerosols? The case of southwestern China
Authors: Qian Yun , Giorgi Filippo
Published: April 2004

We examine multi‐decadal temporal trends and spatial patterns of observed aerosol extinction coefficient and surface air temperature over the Sichuan Basin of Southwestern China. During the last 4 decades average temperature and daily maximum temperature over this region showed statistically significant cooling trends of about −0.1 K/10 yr and −0.14 K/10 yr, respectively. In the same period, significant increasing trends in pollutant emission and aerosol extinction coefficient are observed. Considerations of spatial patterns and temporal trends in the observed pollutant emission, aerosol extinction coefficient and surface air temperature records for the Sichuan Basin indicate a consistent picture of increasing emission of aerosol precursors, resulting in increasing aerosol amounts and extinction coefficient, negative radiative forcing and surface cooling.
Models of the mantle shear velocity and discontinuities in the pattern of lateral heterogeneities
Authors: Gu Yu J. , Dziewonski Adam M. , Su Weijia , Ekström Göran
Published: April 2004

Resolution of the pattern of large‐scale shear velocity variations above and below the known and postulated mantle discontinuities could provide constraints on the nature of mineral phase transitions, changes in composition, and the scale of mantle convection. To achieve good resolution across a full range of depths, we use a diversified data set consisting of body and mantle wave waveforms, travel times, and surface wave phase velocities. Our main focus is on the 670‐km discontinuity, long presumed to be an important barrier, or impediment, to whole mantle convection. Our data set has a relatively high radial resolution throughout the mantle; in the transition zone and some 200 km below it, the long period waveforms, dominated by multiple surface reflections, make a particularly important contribution. We use a local spline support to parameterize the model; this allows us to obtain a smooth model (twice differentiable) and simplifies calculation of the model and its derivatives in applications such as three‐dimensional ray tracing. In one inversion we use a continuous radial representation throughout the mantle; in the other, a discontinuity is allowed across the 670‐km boundary. Both models suggest that the long‐wavelength anomalies of the transition zone and the mantle below 750 km are significantly different. Near 670 km these two models display notable differences in the peak amplitudes and lateral scales of major anomalies. The degree 2 spherical harmonic, which dominates the large‐scale shear velocities in the transition zone, is strongly attenuated at the top of the lower mantle where the power spectrum is essentially white. Resolution tests show that these results are robust, which suggests a possible reorganization of the flow between the upper and lower mantle. At other depths the power spectra of our models as a function of depth indicate a modest change near 400 km, where the dominating effect of degree 5 (shields) is replaced by degree 2 (slabs). The power of the heterogeneity in at mid‐mantle depths is low and nearly flat as a function of spherical harmonic degree up to 𝓁 = 12, with no detectable change near 1000 km. The increase of the power in the lowermost mantle is rather gradual, not characteristic of a discontinuous change. Cross sections of our models at major subduction zones indicate that major downwelling of cold slab material may occur at some locations. On the other hand, there are numerous examples of an abrupt change of the sign of the velocity anomalies across the 670‐km discontinuity.
Transpressive ductile flow and oblique ramping of lower crust in a two‐sided orogen: Insight from quartz grain‐shape fabrics near the Alpine fault, New Zealand
Authors: Little Timothy A.
Published: April 2004

The three‐dimensional (3‐D) grain‐shape fabric (GSF) of deformed quartz veins was measured in 30 samples from the hanging wall of the oblique‐slip Alpine fault in the central Southern Alps, New Zealand. These record aspects of the neotectonic strain experienced by lower crustal rocks in the Pacific Plate as they were transported through a two‐sided orogen. Deformation was nonsteady state: transpression was followed by near‐vertical shearing as the rocks negotiated the oblique footwall ramp of the Alpine fault. At the brittle‐ductile transition, ramping up was accommodated by an escalator‐like back shearing process. This thinned the transpressed crust and boosted dip‐slip rate on the Alpine fault. Mechanically, this suggests a sharp step in the footwall ramp, adjacent to which differential stresses were transiently high. Margin‐parallel motion was partitioned onto these shears. Fabric development is simulated using a 3‐D kinematic model into which we input constraints on plate motion, fault slip rates, crustal structure, fabrics, and geodetic strain in the Southern Alps. This model can explain many aspects of the Southern Alps fabrics, including their nonvertical foliation and lineation. Similarities between the model predictions and the observed fabrics suggest that lower crustal flow in the Pacific Plate mimicked the geodetic velocity pattern at the surface today, with obliquely convergent deformation being distributed across a wide region to the east of the Alpine fault. The model shows that the timescale for an exhumational steady state with respect to deformational fabrics is slow (107 years), a condition which the ∼6 m.y. old Southern Alps have probably not yet achieved.
Aseismic slip and low‐frequency earthquakes in the Bungo channel, southwestern Japan
Authors: Ozawa Shinzaburo , Hatanaka Yuki , Kaidzu Masaru , Murakami Makoto , Imakiire Tetsuo , Ishigaki Yuzo
Published: April 2004

Analysis of Global Positioning System (GPS) data has shown transient crustal deformation in the Bungo channel, in southwestern Japan, since late August 2003, six years after a similar event in 1996–1997. Considering the southeastward motion at many of the GPS sites and the similarity between the 1996–1997 and 2003 events, it is highly likely that the transients were caused by aseismic interplate slip between the Philippine Sea plate and the Amurian plate. The 2003 aseismic slip is estimated beneath the Bungo channel and the relative slip increased with time on the west side, with a moment magnitude (Mw) amounting to 7.0. In contrast to the gradual subsidence of low‐frequency earthquakes which began and ended in coincidence with the 2003 event, the 2003 transient crustal deformation proceeded at a roughly constant rate until the end of November 2003. The Bungo channel area may release energy accumulated from the subduction of the Philippine Sea plate by aseismic slip.
Structural model of the San Bernardino basin, California, from analysis of gravity, aeromagnetic, and seismicity data
Authors: Anderson Megan , Matti Jonathan , Jachens Robert
Published: April 2004

The San Bernardino basin is an area of Quaternary extension between the San Jacinto and San Andreas Fault zones in southern California. New gravity data are combined with aeromagnetic data to produce two‐ and three‐dimensional models of the basin floor. These models are used to identify specific faults that have normal displacements. In addition, aeromagnetic maps of the basin constrain strike‐slip offset on many faults. Relocated seismicity, focal mechanisms, and a seismic reflection profile for the basin area support interpretations of the gravity and magnetic anomalies. The shape of the basin revealed by our interpretations is different from past interpretations, broadening its areal extent while confining the deepest parts to an area along the modern San Jacinto fault, west of the city of San Bernardino. Through these geophysical observations and related geologic information, we propose a model for the development of the basin. The San Jacinto fault‐related strike‐slip displacements started on fault strands in the basin having a stepping geometry thus forming a pull‐apart graben, and finally cut through the graben in a simpler, bending geometry. In this model, the San Bernardino strand of the San Andreas Fault has little influence on the formation of the basin. The deep, central part of the basin resembles classic pull‐apart structures and our model describes a high level of detail for this structure that can be compared to other pull‐apart structures as well as analog and numerical models in order to better understand timing and kinematics of pull‐apart basin formation.