bluuebunny/crossref_metadata_2025 huggingface dataset:
Quercetin enhances TRAIL-mediated apoptosis in colon cancer cells by inducing the accumulation of death receptors in lipid rafts
Authors: Psahoulia Faiy H. , Drosopoulos Konstantinos G. , Doubravska Lenka , Andera Ladislav , Pintzas Alexander
Published: September 2007

Cytokines such as tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) can induce apoptosis in colon cancer cells through engagement of death receptors. Nevertheless, evading apoptosis induced by anticancer drugs characterizes many types of cancers. This results in the need for combination therapy. In this study, we have investigated whether the flavonoid quercetin could sensitize human colon adenocarcinoma cell lines to TRAIL-induced apoptosis. We report that quercetin enhanced TRAIL-induced apoptosis by causing the redistribution of DR4 and DR5 into lipid rafts. Nystatin, a cholesterol-sequestering agent, prevented quercetin-induced clustering of death receptors and sensitization to TRAIL-induced apoptosis in colon adenocarcinoma cells. In addition, our experiments show that quercetin, in combination with TRAIL, triggered the mitochondrial-dependent death pathway, as shown by Bid cleavage and the release of cytochrome c to the cytosol. Together, our findings propose that quercetin, through its ability to redistribute death receptors at the cell surface, facilitates death-inducing signaling complex formation and activation of caspases in response to death receptor stimulation. Based on these results, this study provides a challenging approach to enhance the efficiency of TRAIL-based therapies. [Mol Cancer Ther 2007;6(9):2591–9]
Thiothymidine plus low-dose UVA kills hyperproliferative human skin cells independently of their human papilloma virus status
Authors: Reelfs Olivier , Xu Yao-Zhong , Massey Andrew , Karran Peter , Storey Alan
Published: September 2007

The thymidine analogue 4-thiothymidine (S4TdR) is a photosensitizer for UVA radiation. The UV absorbance spectrum of S4TdR and its incorporation into DNA suggests that it might act synergistically with nonlethal doses of UVA to selectively kill hyperproliferative or cancerous skin cells. We show here that nontoxic concentrations of S4TdR combine with nonlethal doses of UVA to kill proliferating cultured skin cells. Established cell lines with a high fraction of proliferating cells were more sensitive than primary keratinocytes or fibroblasts to apoptosis induction by S4TdR/UVA. Although S4TdR plus UVA treatment induces stabilization of p53, cell death, as measured by apoptosis or clonal survival, occurs to a similar extent in both p53 wild-type and p53-null backgrounds. Furthermore, different types of human papilloma virus E6 proteins, which protect against UVB-induced apoptosis, have little effect on killing by S4TdR/UVA. S4TdR/UVA offers a possible therapeutic intervention strategy that seems to be applicable to human papilloma virus–associated skin lesions. [Mol Cancer Ther 2007;6(9):2487–95]
Sox10 Has a Broad Expression Pattern in Gliomas and Enhances Platelet-Derived Growth Factor-B–Induced Gliomagenesis
Authors: Ferletta Maria , Uhrbom Lene , Olofsson Tommie , Pontén Fredrik , Westermark Bengt
Published: September 2007

In a previously published insertional mutagenesis screen for candidate brain tumor genes in the mouse using a Moloney mouse leukemia virus encoding platelet-derived growth factor (PDGF)-B, the Sox10 gene was tagged in five independent tumors. The proviral integrations suggest an enhancer effect on Sox10. All Moloney murine leukemia virus/PDGFB tumors had a high protein expression of Sox10 independently of malignant grade or tumor type. To investigate the role of Sox10 in gliomagenesis, we used the RCAS/tv-a mouse model in which the expression of retroviral-encoded genes can be directed to glial progenitor cells (Ntv-a mice). Both Ntv-a transgenic mice, wild-type, and Ntv-a p19Arf null mice were injected with RCAS-SOX10 alone or in combination with RCAS-PDGFB. Infection with RCAS-SOX10 alone did not induce any gliomas. Combined infection of RCAS-SOX10 and RCAS-PDGFB in wild-type Ntv-a mice yielded a tumor frequency of 12%, and in Ntv-a Arf−/− mice the tumor frequency was 30%. This indicates that Sox10 alone is not sufficient to induce gliomagenesis but acts synergistically with PDGFB in glioma development. All induced tumors displayed characteristics of PNET-like structures and oligodendroglioma. The tumors had a strong and widely distributed expression of Sox10 and PDGFR-α. We investigated the expression of Sox10 in other human tumors and in a number of gliomas. The Sox10 expression was restricted to gliomas and melanomas. All glioma types expressed Sox10, and tumors of low-grade glioma had a much broader distribution of Sox10 compared with high-grade gliomas. (Mol Cancer Res 2007;5(9):891–7)
Serial Hemodynamics and Complications of Pregnancy in Severe Pulmonary Arterial Hypertension
Authors: Nahapetian Arby , Oudiz Ronald J.
Published: September 2007

We report a case of a woman who became pregnant after the diagnosis of moderate to severe pulmonary hypertension and underwent successful full-term pregnancy. Pulmonary hemodynamics were monitored before pregnancy and in the peripartum period. The patient was followed closely by the cardiology and high-risk obstetric specialists in the outpatient setting until she underwent c-section with epidural anesthesia. Outpatient medical management included twice daily subcutaneous enoxaparin and once daily amlodipine. Immediately prior to cesarian section, and for several days postoperatively, invasive hemodynamic monitoring was employed to titrate medical therapy. During delivery, strict attention focused on limiting intravenous fluids in order to avoid right ventricular volume overload. The postoperative course was complicated by a spontaneous, acute rise in pulmonary vascular resistance, which was managed with intravenous epoprostenol. In addition, abdominal bleeding, likely related to postoperative anticoagulation and platelet dysfunction, was controlled with transfusion and spontaneously resolved after discontinuing the anticoagulation. This case presents a favorable outcome in a pregnant patient undergoing cesarian section despite several complications related to pulmonary hypertension and right ventricular dysfunction, which are often fatal.
Different Acute Tolerance Development to EEG, Psychomotor Performance and Subjective Assessment Effects after Two Intermittent Oral Doses of Alprazolam in Healthy Volunteers
Authors: Barbanoj M.J. , Urbano G. , Antonijoan R. , Ballester M.R. , Valle M.
Published: September 2007

Background/Aims: Benzodiazepines (BZDs) are the most effective of the psychotropic drugs in the treatment of anxiety disorders. Tolerance has been reported for the majority of BZDs after chronic administration. However, little attention has been paid to the possibility that tolerance might be present after the intermittent oral administration of BZDs. The objectives of the present study were to assess tolerance development after the administration of two intermittent single oral doses of alprazolam given 15 days apart in healthy volunteers, and to compare the results obtained using measures from different domains: neurophysiological, psychomotor and subjective. Methods: Twenty-four healthy volunteers received 2 mg of alprazolam orally on two experimental days, 15 days apart. Plasma concentrations and pharmacodynamics (PD) were assessed before drug intake and at different times in the following 24 h. PD was assessed through EEG (relative α and relative β-1 activities), cancellation task (total and correct number of responses) and visual analogue scales (activity and drowsiness). Results: No differences were observed in the PKs of alprazolam between occasions. A proteresis was present in both administrations for impairments of psychomotor performance and relative β-1 activity, whereas it was present only after the second administration for subjective assessments and relative α activity. The proteresis on the second occasion was higher than on the first one. Conclusions: The administration of two single oral doses of alprazolam, 2 weeks apart in healthy volunteers, yielded the same PKs on both occasions, but significant changes were observed in the PD profile. Acute tolerance was observed after the second administration. Two patterns of acute tolerance development were obtained: (1) impairments of psychomotor performance and relative β-1 activity, and (2) subjective assessments and relative α activity.
Assessment of Fetomaternal Hemorrhage by Flow Cytometry and Kleihauer-Betke Test in Rh-Negative Pregnancies
Authors: Savithrisowmya S. , Singh Meenakshi , Kriplani Alka , Agarwal Nutan , Mehra N.K. , Bhatla Neerja
Published: September 2007

Objectives: To assess the efficacy of flow cytometry (FC) in the detection and quantification of fetomaternal hemorrhage (FMH) in comparison to the Kleihauer-Betke test (KBT). Methods: 25 unsensitized Rh-negative mothers who had delivered Rh-positive infants were included. Presence of FMH was determined by KBT and FC using FITC-labeled BRAD-3 antibodies. Results: FMH was detected in 19 (76%) patients by FC and 23 (92%) patients by KBT prior to delivery, and in 21 (84%) patients by FC and 23 (92%) patients by KBT after delivery. The mean volume of FMH in the post-delivery samples by KBT and FC were 0.34 ± 0.26 ml (range 0.05–1.2 ml) and 0.37 ± 0.57 ml (range 0.02–2.6 ml) respectively. The volume of post-delivery FMH estimated by KBT and FC correlated well (r = 0.75; ICC α = 0.73). A higher agreement between KBT and FC was seen in the 0.1–0.5 ml range (ĸ = 0.65; p < 0.01). Conclusions: Both manual KBT and FC using FITC-BRAD-3 antibodies show good sensitivity in detecting and quantifying fetal red cells. There is a good correlation between the methods in the 0.1- to 0.5-ml range of FMH.
Non-Pathogenic Bacterial Flora May Inhibit Colonization by Methicillin-Resistant Staphylococcus aureus in Extremely Low Birth Weight Infants
Authors: Shimizu Akiko , Shimizu Kenji , Nakamura Tomohiko
Published: September 2007

Objectives: To evaluate our hypothesis that non-pathogenic bacterial flora inhibit later colonization with methicillin-resistant Staphylococcus aureus (MRSA) in extremely low birth weight (ELBW) infants, we performed a retrospective investigation of the association between non-pathogenic bacterial flora and later inhibition of colonization by MRSA in ELBW infants. Methods: A total of 110 preterm infants with birth weight <1,000 g admitted to the Neonatal Intensive Care Unit of Nagano Children’s Hospital from January 1997 to December 2003 were analyzed retrospectively with regard to colonization by MRSA during hospitalization. We investigated the incidence of MRSA colonization in 56 infants with non-pathogenic bacterial flora in the oral cavity during the first week after birth and compared them with 54 infants lacking non-pathogenic bacteria. Results: Incidence rate of colonization by MRSA at postnatal week 6 was significantly lower in infants with non-pathogenic bacterial flora in the oral cavity (32.1%) than in infants without such bacteria during the first week of life (77.8%; p < 0.001). Conclusions: The present results suggest an important role for non-pathogenic bacterial flora in the oral cavity during early life in prevention of later MRSA colonization in ELBW infants.
Taxi vs. Taksi: On Orthographic Word Recognition in the Left Ventral Occipitotemporal Cortex
Authors: Kronbichler Martin , Bergmann Jürgen , Hutzler Florian , Staffen Wolfgang , Mair Alois , Ladurner Gunther , Wimmer Heinz
Published: September 2007

The importance of the left occipitotemporal cortex for visual word processing is highlighted by numerous functional neuroimaging studies, but the precise function of the visual word form area (VWFA) in this brain region is still under debate. The present functional magnetic resonance imaging study varied orthographic familiarity independent from phonological-semantic familiarity by presenting orthographically familiar and orthographically unfamiliar forms (pseudohomophones) of the same words in a phonological lexical decision task. Consistent with orthographic word recognition in the VWFA, we found lower activation for familiar compared with unfamiliar forms, but no difference between pseudohomophones and pseudowords. This orthographic familiarity effect in the VWFA differed from the phonological familiarity effect in left frontal regions, where phonologically unfamiliar pseudowords led to higher activation than phonologically familiar pseudohomophones. We suggest that the VWFA not only computes letter string representations but also hosts word-specific orthographic representations. These representations function as recognition units with the effect that letter strings that readily match with stored representations lead to less activation than letter strings that do not.
Functional Neural Networks of Semantic and Syntactic Processes in the Developing Brain
Authors: Brauer Jens , Friederici Angela D.
Published: September 2007

The functional neuroanatomy of language in the adult brain separates semantic and syntactic processes in the superior temporal gyrus (STG) and in the inferior frontal cortex. It is unknown whether a similar specialization is present in the developing brain. Semantic and syntactic aspects of sentence processing were investigated in 5- to 6-year-old children and in adults using functional magnetic resonance imaging. Although adults demonstrated function-specific activations in the STG and the frontal operculum, children showed a large activation overlap for these two language aspects in the STG. Compared to adults, they engaged additional areas in the left and right inferior frontal gyrus, which are known to support resource demanding processes. Thus, the language networks for semantic and syntactic processes are not yet specialized similarly to adults in the developing brain.
Preattentive Sensory Processing as Indexed by the MMN and P3a Brain Responses is Associated with Cognitive and Psychosocial Functioning in Healthy Adults
Authors: Light Gregory A. , Swerdlow Neal R. , Braff David L.
Published: September 2007

Understanding the basic neural processes that underlie complex higher order cognitive operations and psychosocial functioning is a fundamental goal of cognitive neuroscience. Event-related potentials allow investigators to probe the earliest stages of information processing. Mismatch negativity (MMN) and P3a are auditory event-related potential components that reflect automatic sensory discrimination. The aim of the present study was to determine if MMN and P3a are associated with higher order cognitive operations and psychosocial functioning in clinically normal healthy subjects. Twenty adults were assessed using standardized clinical, cognitive, and psychosocial functional instruments. All individuals were within the normal range on cognitive tests and functional ratings. Participants were also tested on a duration-deviant MMN/P3a paradigm (50-msec standard tones, p = .90; 100-msec deviant tones, p = .10; stimulus onset asynchrony [SOA] = 505 msec). Across fronto-central electrode regions, significant correlations were observed between psychosocial functioning and MMN (r = −.62, p < .01) and P3a (r = .63, p < .01) amplitudes. P3a amplitude was also highly associated with immediate and delayed recall of verbal information with robust correlations widely distributed across fronto-central recording areas (e.g., r = .72, p < .001). The latency of the P3a response was significantly associated with both working memory performance (r = −.53, p < .05) and functional ratings (r = −.48, p < .05). Neurophysiological measures of relatively automatic auditory sensory information processing are associated with higher order cognitive abilities and psychosocial functioning in normal subjects. Efficiency at elementary levels of information processing may underlie the successful encoding, retrieval, and discrimination of task-relevant information, which, in turn, facilitates the iterative and responsive processing necessary for adaptive cognitive and social functioning.
The What and How of Observational Learning
Authors: Torriero Sara , Oliveri Massimiliano , Koch Giacomo , Caltagirone Carlo , Petrosini Laura
Published: September 2007

Neuroimaging evidence increasingly supports the hypothesis that the same neural structures subserve the execution, imagination, and observation of actions. We used repetitive transcranial magnetic stimulation (rTMS) to investigate the specific roles of cerebellum and dorsolateral prefrontal cortex (DLPFC) in observational learning of a visuomotor task. Subjects observed an actor detecting a hidden sequence in a matrix and then performed the task detecting either the previously observed sequence or a new one. rTMS applied over the cerebellum before the observational training interfered with performance of the new sequence, whereas rTMS applied over the DLPFC interfered with performance of the previously observed one. When rTMS applied over cerebellar or prefrontal site was delivered after the observational training, no influence was observed on the execution of the task. These results furnish new insights on the neural circuitry involved in the single component of observational learning and allow us to hypothesize that cerebellum and DLPFC interact in planning actions, the former by permitting the acquisition of procedural competencies and the latter by providing flexibility among already acquired solutions.
Regularity Extraction and Application in Dynamic Auditory Stimulus Sequences
Authors: Bendixen Alexandra , Roeber Urte , Schröger Erich
Published: September 2007

Traditional auditory oddball paradigms imply the brain's ability to encode regularities, but are not optimal for investigating the process of regularity establishment. In the present study, a dynamic experimental protocol was developed that simulates a more realistic auditory environment with changing regularities. The dynamic sequences were included in a distraction paradigm in order to study regularity extraction and application. Subjects discriminated the duration of sequentially presented tones. Without relevance to the task, tones repeated or changed in frequency according to a pattern unknown to the subject. When frequency repetitions were broken by a deviating tone, behavioral distraction (prolonged reaction time in the duration discrimination task) was elicited. Moreover, event-related brain potential components indicated deviance detection (mismatch negativity), involuntary attention switches (P3a), and attentional reorientation. These results suggest that regularities were extracted from the dynamic stimulation and were used to predict forthcoming stimuli. The effects were already observed with deviants occurring after as few as two presentations of a standard frequency, that is, violating a just emerging rule. Effects of regularity violation strengthened with the number of standard repetitions. Control stimuli comprising no regularity revealed that the observed effects were due to both improvements in standard processing (benefits of regularity establishment) and deteriorations in deviant processing (costs of regularity violation). Thus, regularities are exploited in two different ways: for an efficient processing of regularity-conforming events as well as for the detection of nonconforming, presumably important events. The present results underline the brain's flexibility in its adaptation to environmental demands.
Neglected Time: Impaired Temporal Perception of Multisecond Intervals in Unilateral Neglect
Authors: Danckert James , Ferber Susanne , Pun Carson , Broderick Carol , Striemer Christopher , Rock Sherry , Stewart Dwight
Published: September 2007

Recent neuroimaging and neuropsychological studies have suggested that the right hemisphere, particularly frontal regions, is important for the perception of the passage of time. We examined the ability to estimate durations of up to 60 sec in a group of eight patients with unilateral neglect. When estimating multisecond intervals, neglect patients grossly underestimated all durations. On average, healthy controls (HC) demonstrated reasonably accurate estimates of all durations tested. Although the right hemisphere lesioned control patients without neglect also tended to underestimate durations, these underestimations were significantly better than the performance of the neglect group. These findings suggest a pivotal role for a right hemisphere fronto-parietal network in the accurate perception of multisecond durations. Furthermore, these findings add to a growing body of literature suggesting that neglect cannot be understood simply in terms of a bias in orienting attention to one side of space. Additional deficits of the kind demonstrated here are likely to be crucial in determining the nature and extent of the loss of conscious awareness for contralesional events.
Feature- and Object-based Attentional Modulation in the Human Auditory “Where” Pathway
Authors: Krumbholz Katrin , Eickhoff Simon B. , Fink Gereon R.
Published: September 2007

Attending to a visual stimulus feature, such as color or motion, enhances the processing of that feature in the visual cortex. Moreover, the processing of the attended object's other, unattended, features is also enhanced. Here, we used functional magnetic resonance imaging to show that attentional modulation in the auditory system may also exhibit such feature- and object-specific effects. Specifically, we found that attending to auditory motion increases activity in nonprimary motion-sensitive areas of the auditory cortical “where” pathway. Moreover, activity in these motion-sensitive areas was also increased when attention was directed to a moving rather than a stationary sound object, even when motion was not the attended feature. An analysis of effective connectivity revealed that the motion-specific attentional modulation was brought about by an increase in connectivity between the primary auditory cortex and nonprimary motion-sensitive areas, which, in turn, may have been mediated by the paracingulate cortex in the frontal lobe. The current results indicate that auditory attention can select both objects and features. The finding of feature-based attentional modulation implies that attending to one feature of a sound object does not necessarily entail an exhaustive processing of the object's unattended features.
Human Factors Issues on the Design of Telepresence Systems
Authors: Deml Barbara
Published: September 2007

The overall aim of this work is to provide some guidelines for the design of tele-presence systems from a human factors point of view. Developers of such human-machine systems face at least two major problems: There are hardly any standard input devices, and guiding design principles are almost missing. Further, most often telepresence systems should enable both a high degree of performance and a high sensation of presence, and yet the relationship between these two variables is still a subject of research. To cope with some of the problems, two experimental studies are presented. Each focuses on a different aspect of interface design, which is of widespread interest in the field of telepresence systems. The first is related to the control of multiple degrees of freedom and the second refers to bimanual input control. Beyond this work, a meta-analytical study is presented to describe the relationship between presence and performance more precisely. Certainly there are more issues that have to be studied (e.g., perceptual aspects) to guide the design of telepresence systems. To provide a framework for these and further human factor aspects, a computer based design guide is suggested at the end. This tool addresses system developers and assists in realizing new interfaces more effectively.
Human Factors for Enhancing Live Video Streams with Virtual Reality: Performance, Situation Awareness, and Feeling of Telepresence
Authors: Pongrac Helena , Leupold Jan , Behrendt Stephan , Färber Berthold , Färber Georg
Published: September 2007

Telepresence systems should be designed to assist the human operator as much as possible to fulfill his task. In order to support the user concerning the visual modality, a system was designed that presents virtual reality images combined together with camera images captured at the remote teleoperator environment.

In this work, two experiments were conducted. In the first, it was shown that presenting a widened field of view to the human operator enhances the human performance and the feeling of telepresence. In the second, it was examined how the transition between video and virtual views has to be designed. Relevant criteria of this transition were chosen and the results show that the operator's rating of quality, feeling of telepresence, and situation awareness are positively affected by variations of the transition parameters. Furthermore, a trade-off between the rating of quality and the situation awareness was observed.

A parameter selection scheme is presented which can serve as a design guideline for combining video and virtual views depending on the desired application.
Transparent Data Reduction in Networked Telepresence and Teleaction Systems. Part II: Time-Delayed Communication
Authors: Hirche Sandra , Buss Martin
Published: September 2007

Two of the major challenges in networked haptic telepresence and teleaction systems are the time delay associated with the data transmission over the network and the limited communication resources. Sophisticated control methods are available for the stabilization in the presence of time delay. The reduction of haptic network traffic, however, is only poorly treated in the known literature. Data reduction approaches for time delayed haptic telepresence are not available at all. This article presents a novel approach to reduce the network traffic in haptic telepresence systems with constant (unknown) time delay. With the proposed deadband control approach data are sent only if the signal to transmit changes more than a given threshold value. In order to guarantee stability with time delay and data reduction a well-known time delay approach, the scattering transformation, is extended. Experimental user studies show that an average network traffic reduction up to 96% is achieved without significantly impairing the perception of the remote environment compared to the standard approach with time delay.
The Effects of Simulated Inertia and Force Prediction on Delayed Telepresence
Authors: Clarke Stella , Schillhuber Gerhard , Zaeh Michael F , Ulbrich Heinz
Published: September 2007

This paper presents two methods aimed at alleviating the negative effects of network delays on teleoperation. The problem of telepresence across delayed networks is well known. A delay in feedback information such as visual and haptic data can make the task at hand very unintuitive and difficult for the operator. The first presented method investigates the hypothesis that simulated inertia in the haptic input device can be a supporting factor during teleoperation across delayed networks. An experiment involving 36 human subjects was carried out under varying network and inertia conditions. Psychophysical experiments were conducted to determine suitable values of inertia. However, simulated inertia was found to be neither a supporting factor nor a detrimental factor to operator performance and immersion in the presence of both delayed and non-delayed networks. The second presented method is a force prediction approach, which extends the teleoperation system with a local force model. This is a learned force model situated locally at the operator-side. Instead of relying on the delayed force signals from the teleoperator-side, haptic information can be extracted from this local force model. An experiment has been created to demonstrate the benefits of this approach in compensating for the instabilities due to time delay.
Observing the Dynamics of Wildland Grass Fires: FireFlux—A Field Validation Experiment
Authors: Clements Craig B. , Zhong Shiyuan , Goodrick Scott , Li Ju , Potter Brian E. , Bian Xindi , Heilman Warren E. , Charney Joseph J. , Perna Ryan , Jang Meongdo , Lee Daegyun , Patel Monica , Street Susan , Aumann Glenn
Published: September 2007

Grass fires, although not as intense as forest fires, present a major threat to life and property during periods of drought in the Great Plains of the United States. Recently, major wildland grass fires in Texas burned nearly 1.6 million acres and destroyed over 730 homes and 1320 other buildings. The fires resulted in the death of 19 people, an estimated loss of 10,000 head of livestock, and more than $628 million in damage, making the 2005/06 fire season the worst on record for the state of Texas.

As an aid to fire management, various models have been developed to describe fire behavior. However, these models strongly emphasize fuels and fail to adequately consider the role of convective dynamics within the atmosphere and its interaction with the fire due to the lack of observational data. To fill this gap, an intensive field measurement campaign called FireFlux was conducted during February 2006 near Houston, Texas. The campaign employed a variety of instrument platforms to collect turbulence data at multiple levels within and immediately downwind of a 155 acre tall-grass prairie burn unit. This paper presents some first-time observations of atmospheric turbulent structures/fluxes associated with intense grass fires and provides a basis to further our understanding of the dynamics of grass fires and their interactions with the atmosphere.
Northern Tales: A Synthesis of MAGS Atmospheric and Hydrometeorological Research
Authors: Szeto K. K. , Stewart R. E. , Yau M. K. , Gyakum J.
Published: September 2007

The Mackenzie Global Energy and Water Cycle Experiment (GEWEX) Study (MAGS) is one of the continental-scale experiments approved specifically by GEWEX to better understand and model water and energy cycling at high latitudes. The project has gone through two phases since its inception in 1994 and conclusion in December 2005. Many scientific results have been achieved through MAGS research to advance our understanding of the Mackenzie River basin climate system. This article is a synthesis of its atmospheric research achievements through an integrative description of the basin's climate system, along with highlights of MAGS research that has advanced our knowledge and understanding of various key aspects of the system. In particular, the significance of MAGS research is discussed in the hancing knowledge of the basin's hydroclimate with focuses on i) the large-scale atmospheric processes that control the transport of water and energy into the basin, and ii) the interactions of the large-scale atmospheric flows with physical features of the basin's environment in affecting the weather and climate of the basin.
Estimated Global Hydrographic Variability
Authors: Forget Gaël , Wunsch Carl
Published: September 2007

An estimate is made of the three-dimensional global oceanic temperature and salinity variability, omitting the seasonal cycle, both as a major descriptive element of the ocean circulation and for use in the error estimates of state estimation. Historical hydrography, recent data from the World Ocean Circulation Experiment, and Argo profile data are all used. Root-mean-square vertical displacements in the upper 300 m of the ocean are generally smaller than 50 m, except in energetic boundary currents and in the North Atlantic subpolar gyre. Variability in temperature and salinity is strongly correlated below the top 100 m. Salinity contributions to sea surface height variability appear more significant at low latitudes than expected, possibly resulting from advective and diffusive processes. Results are generally consistent with altimetric variability under two simple kinematic hypotheses, and much of the observed structure coincides with known dynamical features. A large fraction of the sea surface height variability is consistent with the hypothesis of dominance of the first baroclinic mode.
Origin of the Annual to Decadal Peaks of Variability in the Response of Simple Ocean Models to Stochastic Forcing
Authors: Sirven Jérôme , Herbaut Christophe , Deshayes Julie , Frankignoul Claude
Published: September 2007

The response of the ocean to stochastic forcings is studied in a closed basin, using a simple one-dimensional analytical model. The focus is on the mechanisms that determine the time scales of the response and their possible links with free basin modes. The response may be described as a forced solution plus propagating solutions whose spatial pattern does not depend on the forcing. The propagating solutions are of two types. The first ones propagate eastward and are strongly damped so that their influence remains limited to the western boundary layer. The others are damped long Rossby waves that propagate westward and whose amplitude depends on the spatial extension and the frequency of the forcing. The amplitude increases if the frequency of the forcing is close to the frequency of the basin modes, but the spatial pattern differs from that of the latter; higher frequencies are favored if the zonal extension of the forcing is reduced. The response of a 1.5-layer reduced-gravity ocean model forced by stochastic Ekman pumping confirms the results of the analytical model.
Numerical Simulation of Air–Sea Coupling during Coastal Upwelling
Authors: Perlin Natalie , Skyllingstad Eric D. , Samelson Roger M. , Barbour Philip L.
Published: September 2007

Air–sea coupling during coastal upwelling was examined through idealized three-dimensional numerical simulations with a coupled atmosphere–ocean mesoscale model. Geometry, topography, and initial and boundary conditions were chosen to be representative of summertime coastal conditions off the Oregon coast. Over the 72-h simulations, sea surface temperatures were reduced several degrees near the coast by a wind-driven upwelling of cold water that developed within 10–20 km off the coast. In this region, the interaction of the atmospheric boundary layer with the cold upwelled water resulted in the formation of an internal boundary layer below 100-m altitude in the inversion-capped boundary layer and a reduction of the wind stress in the coupled model to half the offshore value. Surface heat fluxes were also modified by the coupling. The simulated modification of the atmospheric boundary layer by ocean upwelling was consistent with recent moored and aircraft observations of the lower atmosphere off the Oregon coast during the upwelling season. For these 72-h simulations, comparisons of coupled and uncoupled model results showed that the coupling caused measurable differences in the upwelling circulation within 20 km off the coast. The coastal Ekman transport divergence was distributed over a wider offshore extent and a thinner ocean surface boundary layer, with consistently smaller offshore and depth-integrated alongshore transport formed in the upwelling region, in the coupled case relative to the uncoupled case. The results indicate that accurate models of coastal upwelling processes can require representations of ocean–atmosphere interactions on short temporal and horizontal scales.
Seasonal and Spatial Variability of Near-Inertial Kinetic Energy from Historical Moored Velocity Records
Authors: Alford Matthew H. , Whitmont Maya
Published: September 2007

Temporal and spatial patterns of near-inertial kinetic energy (KEmoor) are investigated in a database of 2480 globally distributed, moored current-meter records (deployed on 690 separate moorings) and compared with the distribution of wind-forced mixed-layer energy flux FML. By computing KEmoor using short (30 day) multitaper spectral windows, the seasonal cycle is resolved. Clear winter enhancement by a factor of 4–5 is seen in the Northern Hemisphere for latitudes 25°–45° at all depths <4500 m, in close agreement with the magnitude, phase, and latitudinal dependence of the seasonal cycle of FML. In the Southern Hemisphere, data coverage is poorer, but a weaker seasonal cycle (a factor of 2) in both KEmoor and FML is still resolvable between 35° and 50°. When Wentzel–Kramers–Brillouin (WKB) scaled using climatological buoyancy-frequency profiles, summer KEmoor is approximately constant in depth while showing a clear decrease by a factor of 4–5 from 500 to 3500 m in winter. Spatial coverage is sufficient in the Northern Hemisphere to resolve broad KEmoor maxima in the western portion of each ocean basin in winter, generally collocated with FML maxima associated with storm forcing. The ratio of depth-integrated KEmoor to FML gives a replenishment time scale, which is about 10 days in midlatitudes, consistent with 1) previous estimates of the dissipation time scale of the internal wave continuum and 2) the presence of a seasonal cycle. Its increase to ≈70–80 days at lower latitudes is a possible signature of equatorward propagation of near-inertial waves. The seasonal modulation of the magnitude of KEmoor, its similarity to that in FML, and the depth decay and western intensification in winter but not in summer are consistent with a primarily wind-forced near-inertial field for latitudes poleward of ≈25°.
Effects of the Westerly Wind Stress over the Southern Ocean on the Meridional Overturning
Authors: Hirabara Mikitoshi , Ishizaki Hiroshi , Ishikawa Ichiro
Published: September 2007

Numerical experiments were conducted to clarify the processes through which the Southern Ocean wind affects the meridional overturning (NA cell) associated with North Atlantic Deep Water production. These were based on idealized single- and twin-basin (idealized Atlantic and Pacific Ocean) models with a periodically connected passage under various forcings at the surface. Relationships among the wind stresses, the NA cell, and the buoyancy fluxes were investigated. Increased westerly wind stresses increase the surface buoyancy gains in the Southern Ocean under the density-restoring boundary condition. The buoyancy anomalies excited in the Southern Ocean propagate as baroclinic waves into the northern North Atlantic, modify the density field, and enhance the NA cell, which increases buoyancy losses there until the global buoyancy flux budget balances. The results from experiments using a realistically configured global ocean model confirm that the Southern Ocean wind effects on the NA cell can be understood consistently through thermodynamics and that the wind stresses outside the channel latitudes, as well as those at the Cape Horn latitude, affect the global buoyancy fluxes and the NA cell.
On the Body-Force Term in Internal-Tide Generation
Authors: Garrett Chris , Gerkema Theo
Published: September 2007

The generation of internal tides can be ascribed to the action of a buoyancy force caused by the flow of the barotropic tide over topographic features. It is commonly assumed that the barotropic flow can be taken as hydrostatic, but it is shown here that this leads to a linearized governing equation for the baroclinic tide that is only valid if the baroclinic tide is also hydrostatic. A governing equation for the baroclinic tide, valid for any situation, is derived here and is shown to be exactly equivalent to a simple transformation of the governing equation for the combined barotropic and baroclinic tides.
Measuring Self-Stigma of Mental Illness in China and Its Implications for Recovery
Authors: Fung Kelvin M.T. , Tsang Hector W.H. , Corrigan Patrick W. , Lam Chow S. , Cheng Wai-ming
Published: September 2007

This study translated and validated the Chinese Version of the Self-stigma of Mental Illness Scale (CSSMIS), which may be used to measure self-stigma of mental health consumers in China. We also examined its correlation with self-esteem, self-efficacy and psychosocial treatment compliance. A cross-sectional observational study was implemented. Some 51 males and 57 females who suffered from severe mental illness were recruited from psychiatric settings in Hong Kong. They were required to complete the Chinese Version of the Self-stigma of Mental Illness Scale, the Rosenberg Self-esteem Scale and the Self-efficacy Scale. Their level of compliance during psychosocial treatment and their demographic information were recorded by their case managers. Exploratory factor analysis revealed two homologous factors for the four subscales of the CSSMIS. Factor 1 was related to the negative beliefs and consequences of having mental disorders, whereas Factor 2 was related to positive beliefs. The perceived stigma subscale and the three self-stigma subscales were strongly inter-correlated. Significant correlations were also found between almost all subscales of the CSSMIS and the remaining scales. The psychometric properties of the CSSMIS are statistically acceptable. The results also suggest that stigma played a detrimental role in undermining self-esteem, self-efficacy and psychosocial treatment compliance. Implications for recovery of mental health consumers are discussed.
Formal and Informal Help During the Year After a Suicide Attempt: a One-Year Follow-Up
Authors: Cedereke M. , Öjehagen A.
Published: September 2007

Aims: The aims of this study are threefold: to investigate formal and informal help with clinical and social needs that patients who attempted suicide received during the year after their attempt; to examine whether help from services was estimated to be adequate; and to look at whether patients who repeated suicide attempt(s) during follow-up differed from those who did not.

Methods: The Camberwell Assessment of Need instrument measuring 22 need areas was used in semi-structured interviews with 140 patients at 1 and 12 months after a suicide attempt.

Results: Help given from services was rated as high at both 1 and 12 months in health-related areas, but lower in areas related to social needs. Informal help was initially frequent, with some exceptions. The amount of help from services did not decrease in any need area during follow-up, neither in repeaters nor in non-repeaters. There were no changes in informal help in repeaters, while in non-repeaters informal help decreased in some areas. At both 1 and 12 months, repeaters and non-repeaters mostly found help from services to be adequate. However, in the areas of information, intimate relationships, psychotic symptoms and sexual expression about half of the patients in both groups did not consider that they had received the right type of help.

Conclusions: The generally high level of formal help in health-related areas during the first year after a suicide attempt and the high rated adequacy of help given is satisfactory. However, in certain areas lack of formal help was evident. Informal caregivers contributed significantly to the help that patients received. The use of the Camberwell Assessment of Need instrument could improve observation on needs areas and whether help is available. Perhaps this kind of evaluation could be used earlier than after 1 year in such a vulnerable group as suicide attempters.
Between a Rock and a Hard Place
Authors: Nkomo Mokubung , Akoojee Salim , Motlhanke Simon
Published: September 2007

We argue a case for a `revisioning' of the education policy-implementation nexus in the South African higher education sector. It is proposed that the well-meaning idealism expressed in policy pronouncements is necessarily subject to a host of mediations, national and international, which have a mutative effect on the original intent. This understanding of policy, as `policy pragmatism', is used to understand the discourse in current South African higher education, which although very `efficiency' driven, retains considerable access elements. The article describes how the initial policy intention of `unfettered' access transmutes to a pragmatic, cautious and guided right of entry. Thus, while initial policy propositions are contained in policy, they are not as overtly discernible as would be anticipated.
Leading by Example in a Public Goods Experiment with Heterogeneity and Incomplete Information
Authors: Levati M. Vittoria , Sutter Matthias , van der Heijden Eline
Published: September 2007

We study the effects of leadership on the private provision of a public good when group members are heterogeneously endowed. Leadership is implemented as a sequential public goods game where one group member contributes first and all the others follow. Our results show that the presence of a leader increases average contribution levels but less so than in case of homogeneous endowments. Leadership is almost ineffective, though, if participants do not know the distribution of endowments. Granting the leaders exclusion power does not lead to significantly higher contributions.
Suicide Bombings and Targeted Killings in (Counter-) Terror Games
Authors: Jacobson Daniel , Kaplan Edward H.
Published: September 2007

This article develops sequential game models for key operational terrorist (how often to attack) and government (how often to execute targeted killings) decisions taken during a (counter-) terror campaign such as the second intifada. Key results include the following: The government initiates targeted killings when the marginal number of Israeli civilian lives saved from prevented terror attacks exceeds the marginal number of Palestinian civilian lives lost in such ``hits''; targeted killings are not employed if they are either ineffective or extremely effective at thwarting terror (since terrorists will not induce their use); even after accounting for downstream terror attacks motivated by prior targeted killings, a civilian casualty—minimizing government can optimally order targeted killings over time; and low-level cycles of violence can occur when the government is more patient than the terrorists, but higher, stable levels of violence result when the terrorists are the more patient players in the game.
Fields, Organizations, and Agency
Authors: Cooney Kate
Published: September 2007

Melding key concepts from structuration theory with the organizational field framework, this article builds on current work establishing a micro foundation for neoinstitutional organizations theory. First, the author presents a synthesized theoretic approach to explore the institutionalization process. Then, applying the framework to data from a case study of a welfare-to-work program, the article examines the institutionalization process from the standpoint of one group of organizational actors (social service workers). The analysis shows that institutionalization can be a highly contentious process enacted by knowledgeable actors who engage, reject, and at times transform the value-laden structures in which they are working.
Historical Trends in Childlessness
Authors: Rowland Donald T.
Published: September 2007

Changes in the rates of childlessness over time are explored using European, Australian, American, and Japanese data from censuses, national registers, and large-scale surveys. The trends are remarkably similar across the countries for which data are available: a peak in childlessness rates for the 1880-1910 birth cohorts, a more or less continuous drop across the 1910-1945 birth cohorts, and a steady rise across the cohorts born after the Second World War. Thus, contemporary older adults (particularly the “young old”) belong to generations for which the proportions childless are near the minimum ever recorded. The article examines the factors associated with the changes in rates of childlessness, and more particularly trends in marriage (e.g., median age at marriage and the proportions marrying), trends in family formation (e.g., median age at the first birth and average family size), and the role of voluntary and involuntary factors.