bluuebunny/crossref_metadata_2025 huggingface dataset:
Curcumin (diferuloylmethane) alters the expression profiles of microRNAs in human pancreatic cancer cells
Authors: Sun Michael , Estrov Zeev , Ji Yuan , Coombes Kevin R. , Harris David H. , Kurzrock Razelle
Published: March 2008

Background: A major challenge in cancer chemotherapy has been developing safe and clinically efficacious chemotherapeutic agents. With its low toxicity profile, curcumin (diferuloylmethane), a naturally occurring flavinoid derived from the rhizome of Curcuma longa, has great promise. In vitro and in vivo preclinical studies have shown its inhibitory anticancer, antioxidant, anti-inflammatory, antiproliferative, and proapoptotic activities. The multiple mechanisms of the antitumor effect of curcumin putatively include down-regulating the expression of gene products such as nuclear factor-κB, growth suppression, inducing apoptosis, and modulating various signal transduction pathways and the expression of many oncogenes. The mechanisms underlying the antitumor activity of curcumin have not, however, been completely delineated. Methods: An oligonucleotide microarray chip was developed and used to profile microRNA (miRNA) expressions in pancreatic cells treated with curcumin. Transcripts with regulated expression patterns on the arrays were validated by real-time PCRs. Additionally, potential mRNA targets were analyzed bioinformatically and confirmed with flow cytometry experiments. Results: Curcumin alters miRNA expression in human pancreatic cells, up-regulating miRNA-22 and down-regulating miRNA-199a*, as confirmed by TaqMan real-time PCR. Upregulation of miRNA-22 expression by curcumin or by transfection with miRNA-22 mimetics in the PxBC-3 pancreatic cancer cell line suppressed expression of its target genes SP1 transcription factor (SP1) and estrogen receptor 1 (ESR1), while inhibiting miRNA-22 with antisense enhanced SP1 and ESR1 expression. Conclusions: These observations suggest that modulation of miRNA expression may be an important mechanism underlying the biological effects of curcumin. [Mol Cancer Ther 2008;7(3):464–73]
Astragaloside IV Improved Intracellular Calcium Handling in Hypoxia-Reoxygenated Cardiomyocytes via the Sarcoplasmic Reticulum Ca2+-ATPase
Authors: Xu Xiao-Le , Chen Xiang-Jian , Ji Hui , Li Ping , Bian Yun-Yun , Yang Di , Xu Jin-Dan , Bian Zhi-Ping , Zhang Ji-Nan
Published: March 2008

Although astragaloside IV, a saponin isolated from Astragalus membranaceus, has been shown to protect the myocardium against ischemia/reperfusion injury, its effect on the status of sarcoplasmic reticulum (SR) Ca2+ transport in the injured myocardium remains largely unknown. In this study, we investigated whether in cultured cardiomyocytes subjected to hypoxia and reoxygenation (H/R) administration of astragaloside IV during H/R attenuates the myocardial cell injury and prevents changes in Ca2+ handling activities and gene expression of SR Ca2+ pump. Cultured cardiomyocytes from neonatal rats were exposed to 6 h of hypoxia followed by 3 h of reoxygenation. Myocyte injury was determined by the release of cardiac troponin I in supernatant. Astragaloside IV significantly inhibited cardiac troponin I release after H/R in a dose-dependent manner. The diastolic [Ca2+]i measured with Fura-2/AM was significantly increased after reoxygenation. Astragaloside IV prevented the rise of diastolic [Ca2+]i and the depression of caffeine-induced Ca2+ transients caused by H/R. Furthermore, the observed depressions in SR Ca2+-ATPase activity as well as the mRNA and protein expression of SR Ca2+-ATPase in hypoxic-reoxygenated cardiomyocytes were attenuated by astragaloside IV treatment. These results suggest that the beneficial effect of astragaloside IV in H/R-induced injury may be related to normalization of SR Ca2+ pump expression and, thus, may prevent the depression in SR Ca2+ handling.
Impact of a Basic Nutrition Course for Residents at a Faculty Hospital
Authors: Kirdak Turkay , Iscimen Remzi , Tanir Burak , Kelebek Nermin , Keskin Murat , Korun Nusret
Published: March 2008

Background/Aims: To assess whether a basic nutrition course for residents at a faculty hospital improves their knowledge of nutrition and increases the number of consultation requests for nutrition by alerting participants to the high prevalence of undernutrition in hospitals. Methods: The residents from 34 departments of basic, internal and surgical sciences were recruited to take a 1-day course. Questionnaires, designed to assess knowledge of nutrition, were completed at the beginning and at the end of the course. The results of the questionnaires and the number of consultation demands for nutrition before and after the course were compared. Results: The results of 161 participants were evaluated. The mean (±SE) numbers of correct answers given to the first and second questionnaires were 14.9 ± 0.22 and 18.7 ± 0.21, respectively (p < 0.01). When the number of requests for nutrition consultation during 7-month periods (just before and after the course) were compared, the mean number of requests in each month during these periods were found to be 1.81 ± 0.58 and 4.06 ± 1.20, respectively (p < 0.01). Conclusions: A short course of basic nutrition for residents improves their basic knowledge and leads to an increase in the number of consultation requests for nutritional support.
Fronto-temporal Interactions during Overt Verbal Initiation and Suppression
Authors: Allen Paul , Mechelli Andrea , Stephan Klaas E. , Day Fern , Dalton Jeffery , Williams Steven , McGuire Philip K.
Published: March 2008

The Hayling Sentence Completion Task (HSCT) is known to activate left hemisphere frontal and temporal language regions. However, the effective connectivity between frontal and temporal language regions associated with the task has yet to be examined. The aims of the study were to examine activation and effective connectivity during the HSCT using a functional magnetic resonance imaging (fMRI) paradigm in which participants made overt verbal responses. We predicted that producing an incongruent response (response suppression), compared to a congruent one (response initiation), would be associated with greater activation in the left prefrontal cortex and an increase in the effective connectivity between temporal and frontal regions. Fifteen participants were scanned while completing 80 sentence stems. The congruency and constraint of sentences varied across trials. Dynamic Causal Modeling (DCM) and Bayesian Model Selection (BMS) were used to compare a set of alternative DCMs of fronto-temporal connectivity. The HSCT activated regions in the left temporal and prefrontal cortices, and the cuneus. Response suppression was associated with greater activation in the left middle and orbital frontal gyri and the bilateral precuneus than response initiation. Left middle temporal and frontal regions identified by the conventional fMRI analyses were entered into the DCM analysis. Using a systematic BMS procedure, the optimal DCM showed that the connection from the left middle temporal gyrus, which was driven by verbal stimuli per se, was significantly increased in strength during response suppression compared to initiation. Greater effective connectivity between left temporal and prefrontal regions during response suppression may reflect the transfer of information from posterior temporal regions where semantic and lexical information is stored to prefrontal regions where it is manipulated in preparation for an appropriate response.
The Sense of Touch: Embodied Simulation in a Visuotactile Mirroring Mechanism for Observed Animate or Inanimate Touch
Authors: Ebisch Sjoerd J. H. , Perrucci Mauro G. , Ferretti Antonio , Del Gratta Cosimo , Romani Gian Luca , Gallese Vittorio
Published: March 2008

Previous studies have shown a shared neural circuitry in the somatosensory cortices for the experience of one's own body being touched and the sight of intentional touch. Using functional magnetic resonance imaging (fMRI), the present study aimed to elucidate whether the activation of a visuotactile mirroring mechanism during touch observation applies to the sight of any touch, that is, whether it is independent of the intentionality of observed touching agent. During fMRI scanning, healthy participants viewed video clips depicting a touch that was intentional or accidental, and occurring between animate or inanimate objects. Analyses showed equal overlapping activation for all the touch observation conditions and the experience of one's own body being touched in the bilateral secondary somatosensory cortex (SII), left inferior parietal lobule (IPL)/supramarginal gyrus, bilateral temporal-occipital junction, and left precentral gyrus. A significant difference between the sight of an intentional touch, compared to an accidental touch, was found in the left primary somatosensory cortex (SI/Brodmann's area [BA] 2). Interestingly, activation in SI/BA 2 significantly correlated with the degree of intentionality of the observed touch stimuli as rated by participants. Our findings show that activation of a visuotactile mirroring mechanism for touch observation might underpin an abstract notion of touch, whereas activation in SI might reflect a human tendency to “resonate” more with a present or assumed intentional touching agent.
Attention Modulates Initial Stages of Visual Word Processing
Authors: Ruz María , Nobre Anna C.
Published: March 2008

Selective attention has the potential to enhance the initial processing of objects, their spatial locations, or their constituent features. The present study shows that this capacity to modulate initial stages of processing also applies to linguistic attributes. A cueing paradigm focused attention at different levels of word representations on a trial-by-trial basis to study the time course of attentional modulation on visual word processing by means of a high-density electrophysiology recording system. Attention to different linguistic attributes modulated components related to semantic, phonological, and orthographic stages of word processing. Crucially, the N200, associated with initial stages of orthographic decoding, was enhanced by attention to the letter pattern of words. These results suggest that top-down attention has the capacity to enhance initial perceptual stages of visual word processing and support the flexibility of attention in modulating different levels of information processing depending on task goals.
Virtual Training via Vibrotactile Arrays
Authors: Bloomfield Aaron , Badler Norman I.
Published: March 2008

What is often missing from many virtual worlds and training simulations is a physical sense of the confinement and constraint of the virtual environment. We present a method for providing localized cutaneous vibratory feedback to the user's right arm. We created a sleeve of tactors linked to a real-time human model; the tactors activate to apply sensation to the corresponding body area. The hypothesis is that vibrotactile feedback to body areas provides the wearer sufficient guidance to assume correct body configurations and ascertain the existence and physical realism of access paths. We present the results of human subject experiments that study both explicit and implicit training of skills using vibrotactile arrays. Implicitly, collision awareness is achieved by activating the appropriate tactor when a body part collides with the scene; thus, the user will attempt to correct his or her body configuration. Explicitly, we use the tactors to guide the body into the proper configuration. The results of human subject experiments clearly show that the use of full arm vibrotactile feedback improves performance over purely visual feedback for navigating the virtual environment, as well as allowing easy acquisition of new skills. These results validate the empirical performance of this concept.
Nematodes from the Gulf of California. Part 1. The genera Ceramonema Cobb, 1920, Pselionema Cobb in Cobb, 1933 and Pterygonema Gerlach, 1954 (Nematoda: Ceramonematidae)
Authors: Mundo-Ocampo Manuel , Tandingan De Ley Irma , Rocha-Olivares Axayácatl , Baldwin James , Holovachov Oleksandr , De Ley Paul
Published: March 2008

The morphology and morphometry of nematodes of six species of the family Ceramonematidae is described using light and scanning electron microscopy. In this paper, we describe two new species and redescribe two known species of Ceramonema and one new species each of Pselionema and Pterygonema. Ceramonema altogolfi sp. n. is characterised by the 0.8-1.3 mm long body, 187-247 body annules, weakly developed zygapophyses, presence of intracuticular vacuoles, sexual dimorphism in amphid shape, presence of vaginal sclerotisation, complex gubernaculum and relatively uniform anal and cloacal annules, whilst C. inguinispina sp. n. has a 0.8-1.1 mm long body, 135-191 body annules, weakly developed zygapophyses, presence of intracuticular vacuoles, sexual dimorphism in amphid shape, absence of vaginal sclerotisation, thorn-shaped precloacal projection, plate-like gubernaculum and double cloacal annule. Pselionema psednum sp. n. is distinguished by 1.4-1.7 mm long body, 251-292 body annules, weakly developed zygapophyses, absence of intracuticular vacuoles, sexual dimorphism in amphid shape and Pterygonema mexicanum sp. n. is characterised by having amphids lacking a central thorn-like projection and pharynx with a distinct posterior glandular bulb. Populations of Ceramonema rectum and Ceramonema cf. yunfengi are also described. The male cloacal region of the species examined appears to be a rich potential source of taxonomic characters that have as yet received insufficient attention for this family.
Stochastic Nature of Physical Parameterizations in Ensemble Prediction: A Stochastic Convection Approach
Authors: Teixeira João , Reynolds Carolyn A.
Published: March 2008

In this paper it is argued that ensemble prediction systems can be devised in such a way that physical parameterizations of subgrid-scale motions are utilized in a stochastic manner, rather than in a deterministic way as is typically done. This can be achieved within the context of current physical parameterization schemes in weather and climate prediction models. Parameterizations are typically used to predict the evolution of grid-mean quantities because of unresolved subgrid-scale processes. However, parameterizations can also provide estimates of higher moments that could be used to constrain the random determination of the future state of a certain variable. The general equations used to estimate the variance of a generic variable are briefly discussed, and a simplified algorithm for a stochastic moist convection parameterization is proposed as a preliminary attempt. Results from the implementation of this stochastic convection scheme in the Navy Operational Global Atmospheric Prediction System (NOGAPS) ensemble are presented. It is shown that this method is able to generate substantial tropical perturbations that grow and “migrate” to the midlatitudes as forecast time progresses while moving from the small scales where the perturbations are forced to the larger synoptic scales. This stochastic convection method is able to produce substantial ensemble spread in the Tropics when compared with results from ensembles created from initial-condition perturbations. Although smaller, there is still a sizeable impact of the stochastic convection method in terms of ensemble spread in the extratropics. Preliminary simulations with initial-condition and stochastic convection perturbations together in the same ensemble system show a promising increase in ensemble spread and a decrease in the number of outliers in the Tropics.
Ensemble Data Assimilation with the NCEP Global Forecast System
Authors: Whitaker Jeffrey S. , Hamill Thomas M. , Wei Xue , Song Yucheng , Toth Zoltan
Published: March 2008

Real-data experiments with an ensemble data assimilation system using the NCEP Global Forecast System model were performed and compared with the NCEP Global Data Assimilation System (GDAS). All observations in the operational data stream were assimilated for the period 1 January–10 February 2004, except satellite radiances. Because of computational resource limitations, the comparison was done at lower resolution (triangular truncation at wavenumber 62 with 28 levels) than the GDAS real-time NCEP operational runs (triangular truncation at wavenumber 254 with 64 levels). The ensemble data assimilation system outperformed the reduced-resolution version of the NCEP three-dimensional variational data assimilation system (3DVAR), with the biggest improvement in data-sparse regions. Ensemble data assimilation analyses yielded a 24-h improvement in forecast skill in the Southern Hemisphere extratropics relative to the NCEP 3DVAR system (the 48-h forecast from the ensemble data assimilation system was as accurate as the 24-h forecast from the 3DVAR system). Improvements in the data-rich Northern Hemisphere, while still statistically significant, were more modest. It remains to be seen whether the improvements seen in the Southern Hemisphere will be retained when satellite radiances are assimilated. Three different parameterizations of background errors unaccounted for in the data assimilation system (including model error) were tested. Adding scaled random differences between adjacent 6-hourly analyses from the NCEP–NCAR reanalysis to each ensemble member (additive inflation) performed slightly better than the other two methods (multiplicative inflation and relaxation-to-prior).
Evolving Complex Electrical Structures of the STEPS 25 June 2000 Multicell Storm
Authors: Weiss Stephanie A. , Rust W. David , MacGorman Donald R. , Bruning Eric C. , Krehbiel Paul R.
Published: March 2008

Data from a three-dimensional lightning mapping array (LMA) and from two soundings by balloon-borne electric field meters (EFMs) were used to analyze the electrical structures of a multicell storm observed on 25 June 2000 during the Severe Thunderstorm Electrification and Precipitation Study (STEPS). This storm had a complex, multicell structure with four sections, each of whose electrical structure differed from that of the others during all or part of the analyzed period. The number of vertically stacked charge regions in any given section of the storm ranged from two to six. The most complex charge and lightning structures occurred in regions with the highest reflectivity values and the deepest reflectivity cores. Intracloud flashes tended to concentrate in areas with large radar reflectivity values, though some propagated across more than one core of high reflectivity or into the low-reflectivity anvil. Intracloud lightning flash rates decreased as the vertical extent and maximum value of reflectivity cores decreased. Cloud-to-ground flash rates increased as cores of high reflectivity descended to low altitudes. Most cloud-to-ground flashes were positive. All observed positive ground flashes initiated between the lowest-altitude negative charge region and a positive charge region just above it. The storm’s complexity makes it hard to classify the vertical polarity of its overall charge structure, but most of the storm had a different vertical polarity than what is typically observed outside the Great Plains. The electrical structure can vary considerably from storm to storm, or even within the same storm, as in the present case.
An Ensemble Multiscale Filter for Large Nonlinear Data Assimilation Problems
Authors: Zhou Yuhua , McLaughlin Dennis , Entekhabi Dara , Ng Gene-Hua Crystal
Published: March 2008

Operational data assimilation problems tend to be very large, both in terms of the number of unknowns to be estimated and the number of measurements to be processed. This poses significant computational challenges, especially for ensemble methods, which are critically dependent on the number of replicates used to derive sample covariances and other statistics. Most efforts to deal with the related problems of computational effort and sampling error in ensemble estimation have focused on spatial localization. The ensemble multiscale Kalman filter described here offers an alternative approach that effectively replaces, at each update time, the prior (or background) sample covariance with a multiscale tree. The tree is composed of nodes distributed over a relatively small number of discrete scales. Global correlations between variables at different locations are described in terms of local relationships between nodes at adjacent scales (parents and children). The Kalman updating process can be carried out very efficiently on such a tree, especially if the update calculations exploit the tree’s parallel structure. In fact, the resulting savings in effort far exceeds the additional work required to construct the tree. The tree-identification process offers possibilities for introducing localization in scale, which can be used instead of or in addition to localization in space. The multiscale filter is able to continually adapt to changing problem scales through associated changes in the tree structure. This is illustrated with a large (106) unknown turbulent fluid flow example that generates dynamic features that span a wide range of time and space scales. This filter is able to track changing features over long distances without any spatial localization, using a moderate ensemble size of 54. The computational savings provided by the multiscale approach, combined with opportunities for hybrid localization over both space and scale, offer significant practical benefits for large data assimilation applications.
Moving Vortices on the Sphere: A Test Case for Horizontal Advection Problems
Authors: Nair Ramachandran D. , Jablonowski Christiane
Published: March 2008

A new two-dimensional advection test on the surface of the sphere is proposed. The test combines a solid-body rotation and a deformational flow field to form moving vortices over the surface of the sphere. The resulting time-dependent deforming vortex centers are located on diametrically opposite sides of the sphere and move along a predetermined great circle trajectory. The horizontal wind field is deformational and nondivergent, and the analytic solution is known at any time. During one revolution around the sphere the initially smooth transported scalar develops strong gradients. Such an approach is therefore more challenging than existing advection test cases on the sphere. To demonstrate the effectiveness and versatility of the proposed test, three different advection schemes are employed, such as a discontinuous Galerkin method on a cubed-sphere mesh, a classical semi-Lagrangian method, and a finite-volume algorithm with adaptive mesh refinement (AMR) on a regular latitude–longitude grid. The numerical results are compared with the analytic solution for different flow orientation angles on the sphere.
Radar Observations of Intense Orographic Precipitation Associated with Typhoon Xangsane (2000)
Authors: Yu Cheng-Ku , Cheng Lin-Wen
Published: March 2008

With measurements from two ground-based Doppler radars located in northern Taiwan, this study documents the detailed aspects of intense orographic precipitation associated with Typhoon Xangsane (2000) as it moved northward immediately off the eastern coast of Taiwan, bringing strong low-level northeasterly to north-northeasterly winds impinging on the mountainous northern coast. With relatively good, persistent coverage of radar echoes on both inland and upstream regions, this particular event provides a unique description of the orographic precipitation and its relationship with orographic geometry, strong upstream oncoming flow, and the precipitation inherently associated with typhoon circulations. In this case, the heaviest precipitation was observed to occur primarily over two coastal mountain barriers: Mount Da-Tun (DT) and the Nangang-Keelung Range (NKR). Barrier DT is an approximately 3D mountain barrier, and the NKR, adjacent to the southeast of DT, is a relatively lower, narrower 2D mountain range. In particular, the distinct distribution and intensity of precipitation over the two barriers were observed. Analyses of vertical cross sections passing through the major regions of heavy precipitation over DT and NKR indicate the region of low-level heavy precipitation tended to shift downstream as the low-level oncoming flow intensified, and the precipitation exhibited a deeper, wider extent and stronger intensity at stronger oncoming flow regimes. However, changes in the location of maximum precipitation over DT (NKR) were confined mainly to regions over windward slopes (near and downstream of the mountain crest). The degree of downstream shift of low-level heaviest precipitation with respect to different magnitudes of oncoming flow was relatively limited (∼8 km) over NKR, as compared with a larger downstream shift of ∼15–17 km over DT. This contrasting aspect can be understood as a consequence of a longer “lifting section” and relatively lower fall speed of hydrometeors over the windward slope of DT. In addition, the precipitation inherently associated with the typhoon circulations was found to be an important contributor to the observed variations in precipitation intensity over DT and NKR. Stronger background typhoon precipitation and a shorter downstream shift of precipitation (i.e., a quasi-stationary precipitation feature) over NKR may explain the fact of larger precipitation accumulation observed over this narrower, lower barrier.
Sea Surface Temperature Feedback Extends the Predictability of Tropical Intraseasonal Oscillation
Authors: Fu Xiouhua , Yang Bo , Bao Qing , Wang Bin
Published: March 2008

The possible impacts of different sea surface temperature (SST) configurations on the predictability of the boreal summer tropical intraseasonal oscillation (TISO) are assessed with a series of ensemble forecasts. The five different lower boundary conditions examined in this study are, respectively, (i) the fully interactive ocean–atmosphere coupling, (ii) “smoothed” SST, which excludes the intraseasonal signal from sea surface forcing, (iii) damped persistent SST, (iv) coupling to a slab mixed-layer ocean, and (v) daily SST from the coupled forecast. The full atmosphere–ocean coupling generates an interactive SST that results in the highest TISO predictability of about 30 days over Southeast Asia. The atmosphere-only model is capable of reaching this predictability if the ensemble mean daily SST forecast by the coupled model is used as the lower boundary condition, which suggests that, in principle, the so-called tier-one and tier-two systems have the same predictability for the boreal summer TISO. The atmosphere-only model driven by either smoothed or damped persistent SSTs, however, has the lowest predictability (∼20 days). The atmospheric model coupled to a slab mixed-layer ocean achieves a predictability of 25 days. The positive SST anomalies in the northern Indo–western Pacific Oceans trigger convective disturbances by moistening and warming up the atmospheric boundary layer. The seasonal mean easterly shear intensifies the anomalous convection by enhancing the surface convergence. An overturning meridional circulation driven by the off-equatorial anomalous convection suppresses the near-equatorial convection and enhances the northward flows, which further intensify the off-equatorial surface convergence and the TISO-related convection. Thus, the boreal summer mean easterly shear and the overturning meridional circulation in the northern Indo–western Pacific sector act as “amplifiers” for the SST feedback to the convection of the TISO.
A Simple Parameterization for Detrainment in Shallow Cumulus
Authors: de Rooy Wim C. , Siebesma A. Pier
Published: March 2008

For a wide range of shallow cumulus convection cases, large-eddy simulation (LES) model results have been used to investigate lateral mixing as expressed by the fractional entrainment and fractional detrainment rates. It appears that the fractional entrainment rates show much less variation from hour to hour and case to case than the fractional detrainment rates. Therefore, in the parameterization proposed here, the fractional entrainment rates are assumed to be described as a fixed function of height, roughly following the LES results. Based on the LES results a new, more flexible parameterization for the detrainment process is developed that contains two important dependencies. First, based on cloud ensemble principles it can be understood that deeper cloud layers call for smaller detrainment rates. All current mass flux schemes ignore this cloud-height dependence, which evidently leads to large discrepancies with observed mass flux profiles. The new detrainment formulation deals with this dependence by considering the mass flux profile in a nondimensionalized way. Second, both relative humidity of the environmental air and the buoyancy excess of the updraft influence the detrainment rates and, therefore, the mass flux profiles. This influence can be taken into account by borrowing a parameter from the buoyancy-sorting concept and using it in a bulk sense. LES results show that with this bulk parameter, the effect of environmental conditions on the fractional detrainment rate can be accurately described. A simple, practical but flexible parameterization for the fractional detrainment rate is derived and evaluated in a single-column model (SCM) for three different shallow cumulus cases, which shows the clear potential of this parameterization. The proposed parameterization is an attractive and more robust alternative for existing, more complex, buoyancy-sorting-based mixing schemes, and can be easily incorporated in current mass flux schemes.
Getting the Most out of Ensemble Forecasts: A Valuation Model Based on User–Forecast Interactions
Authors: Millner Antony
Published: March 2008

A flexible theoretical model of perceived forecast value is proposed that explicitly includes the effects of user and ensemble characteristics and their interactions. The model can be applied to arbitrary decision problems and is sensitive to a much wider range of factors than traditional forecast valuation models. A simple illustration of its application to the cost–loss decision problem familiar from the forecast valuation literature is discussed. It is shown that perceived value is highly sensitive to perceived model accuracy and that in most cases a high level of perceived accuracy is required for the forecasts to be thought to have any value at all. Decisions with a cost–benefit ratio that is close to the climatological probability of the adverse event are shown to be less sensitive to perceived accuracy. The model shows that it is possible for perceived value to remain unchanged when perceived accuracy increases, thus suggesting an explanation for why forecast uptake often does not increase after improvements in model performance are made. Last, it is argued that attempts to increase forecast uptake should be targeted at those users whose cost–benefit ratios fall in a restricted range that depends on the climatological probability of the event and an objective measure of the ensemble accuracy.
Constraints on Model Response to Greenhouse Gas Forcing and the Role of Subgrid-Scale Processes
Authors: Sanderson Benjamin M. , Knutti R. , Aina T. , Christensen C. , Faull N. , Frame D. J. , Ingram W. J. , Piani C. , Stainforth D. A. , Stone D. A. , Allen M. R.
Published: March 2008

A climate model emulator is developed using neural network techniques and trained with the data from the multithousand-member climateprediction.net perturbed physics GCM ensemble. The method recreates nonlinear interactions between model parameters, allowing a simulation of a much larger ensemble that explores model parameter space more fully.

The emulated ensemble is used to search for models closest to observations over a wide range of equilibrium response to greenhouse gas forcing. The relative discrepancies of these models from observations could be used to provide a constraint on climate sensitivity. The use of annual mean or seasonal differences on top-of-atmosphere radiative fluxes as an observational error metric results in the most clearly defined minimum in error as a function of sensitivity, with consistent but less well-defined results when using the seasonal cycles of surface temperature or total precipitation.

The model parameter changes necessary to achieve different values of climate sensitivity while minimizing discrepancy from observation are also considered and compared with previous studies. This information is used to propose more efficient parameter sampling strategies for future ensembles.
Statistical Prediction of Weekly Tropical Cyclone Activity in the Southern Hemisphere
Authors: Leroy Anne , Wheeler Matthew C.
Published: March 2008

A statistical prediction scheme, employing logistic regression, is developed to predict the probability of tropical cyclone (TC) formation in zones of the Southern Hemisphere during forthcoming weeks. Through physical reasoning, examination of previous research, and some new analysis, five predictors were chosen for this purpose: one representing the climatological seasonal cycle of TC activity in each zone, two representing the eastward propagation of the Madden–Julian oscillation (MJO), and a further two representing the leading patterns of interannual sea surface temperature variability in the Indo-Pacific Oceans. Cross-validated hindcasts were generated, being careful to use the predictors at lags that replicate what can be performed in real time. All predictors contribute significantly to the skill of the hindcasts for at least some leads in the majority of zones. In particular, it is found that inclusion of indices of the MJO as predictors leads to increased skill out to about the third week. Beyond the third week, the skill asymptotically approaches that which can be achieved through consideration of the seasonal cycle and interannual variability alone. Furthermore, the importance of a simple consideration of the seasonal cycle of TC activity for intraseasonal TC prediction, for all forecast leads, is demonstrated.
Impact of Stochastic Convection on the Ensemble Transform
Authors: Reynolds Carolyn A. , Teixeira Joao , McLay Justin G.
Published: March 2008

The impact of stochastic convection on ensembles produced using the ensemble transform (ET) initial perturbation scheme is examined. This note compares the behavior of ensemble forecasts based only on initial ET perturbations with the behavior of ensemble forecasts based on the ET initial perturbations and forecasts that include stochastic convection. It is illustrated that despite the fact that stochastic convection occurs only after the forecast integrations have started, it induces changes in the initial perturbations as well. This is because the ET is a “cycling” scheme, in which previous short-term forecasts are used to produce the initial perturbations for the current forecast. The stochastic convection scheme induces rapid perturbation growth in regions where convection is active, primarily in the tropics. When combined with the ET scheme, this results in larger initial perturbation variance in the tropics, and, because of a global constraint on total initial perturbation variance, smaller initial perturbation variance in the extratropics. Thus, the inclusion of stochastic convection helps to mitigate a problem found in the practical implementation of the ET, namely, that of too little initial variance in the tropics and too much in the extratropics. Various skill scores show that stochastic convection improves ensemble performance in the tropics, with little impact to modest improvement in the extratropics. Experiments performed using the initial perturbations from the control ensemble run but forecast integrations using the stochastic convection scheme indicate that the improved performance of the stochastic convection ensemble at early forecast times is due to both “indirect” changes in the initial perturbations and “direct” changes in the forecast. At later forecast times, it appears that most of the improvement can be gained through stochastic convection alone.
Friends at Work
Authors: Song Seok-Hwi , Olshfski Dorothy
Published: March 2008

Managers and scholars have always been ambivalent about the value of friendships among employees to the organization, although anyone who has worked in an office setting knows that working in a friendly place is much more preferable than the alternative. The major focus on office friendship has been on the negative side: Friendship can be related to nepotism; favoritism; gossip; displacement of loyalty; and negative, time-consuming organizational politics. This article offers a more balanced assessment of friendship. The authors examine the opportunity to form friendships and the strength of friendship between employees and their manager and their relationship to a positive work attitude. While examining two countries (South Korea and the United States), the authors find that although the opportunity to form friendships and the strength of that relationship vary by country, friendships between superior and subordinate can positively affect work attitudes.
Decision Making in a Time of Significant Reform
Authors: Greener Ian
Published: March 2008

This article utilizes three empirical studies to examine the organizational and policy context within which health managers find themselves today, asking three questions of extreme relevance for the area of health organizational reform in a period in which the pace and scope of change are intense: What strategies do public service managers employ to make sure they stay up to date with what is required of them? How do public service managers deal with the insight that much of what they are accountable for is actually outside of their control? And when a demanding and prescriptive performance measurement system is introduced, how does it affect public service managers? The article considers a range of organizational settings, looking for commonalities in the problems that managers face and the strategies they employ to attempt to deal with them. Linking its findings with previous studies, it suggests a number of implications for the future of management in the National Health Service.
Generic Womanhood
Authors: King Neal
Published: March 2008

Content analysis of 291 cop action films reveals the gendering of heroism by Hollywood filmmakers. Employing Griswold's “cultural diamond” framework, this study frames the genre as product of a Hollywood labor market dominated by men but increasingly integrated. Women among its heroes continue disproportionately to be rookies and to work a narrow range of cases involving undercover operations and the detection of serial killers. Women in cop action films are also more likely than men to begin heterosexual affairs and to arrest or kill their lovers. However, they engage in less combat and do not confront or engage in police corruption. The most aggressive uses of and contest over state power thus turn out to be men's work in these films. The genre implies a collective common sense among industry professionals about the limits of men's professional ethics and women's professional achievements.
Postponed Marriage
Authors: Nemoto Kumiko
Published: March 2008

Sociologists have argued that marriage today is based on individual desires, democratic contracts, and self-development. However, feminist scholars have criticized such a view of modern marriage, arguing that it obscures persistent inequality and social restrictions in marriage. Drawing on in-depth interviews with 26 highly educated Japanese women, this article argues that persistent gender inequalities shape women's decisions to postpone marriage in Japan. The article analyzes the emotional ambivalence and contradictions in women's decisions to postpone marriage. The women discussed here have intentionally or unintentionally distanced themselves from (1) marriage in general, which they view as inhibiting autonomy, (2) marriage with a sexist man, (3) marriage with a man who has rejected them, and (4) marriage with a man who has less income and/or education than they do.
The Changing Agricultural Demography of India
Authors: Sharma Amrita
Published: March 2008

The demography of Indian agriculture is changing fast. There are clear signs of people fast moving out of agriculture, especially in the form of rural youth practicing farming part-time and ageing of the farmer population in several pockets of the country. Given the current growth performance of Indian economy, such changes in agriculture are only expected to intensify. What would Indian agriculture look like in 2025/2050? Who will stay and who will move on? In an attempt to answer these questions, this article takes a look at one of the leading indicators and important demographic trends in Indian agriculture, that is, withdrawal of rural youth from farming, covering 14 locations in 13 states across the country.
India's Water Future 2050
Authors: Verma Shilp , Phansalkar Sanjiv J.
Published: March 2008

The debate on India's ambitious river-linking project is highly polarized. While the proponents insist that scores of highly qualified engineer-years have been invested in studying the feasibility of the links, the analysis is not available in the public domain. On the other hand, the opponents argue that the project is a conspiracy to hide the past inefficiencies of the irrigation bureaucracy; and yet, the alternatives proposed by them for India's impending water challenge also seem far from concrete. This article critically examines the National Commission Integrated Water Resource Development (NCIWRD) report, which has repeatedly been cited as the basis for planning and justifying the project, and outlines a framework for research which will help in raising the level of this important national debate by helping to develop a refined, textured and nuanced understanding of ‘India's water future 2050’.
Mechanical properties and bending behaviour of metal foils
Authors: Diehl A , Engel U , Geiger M
Published: March 2008

Ongoing miniaturization in various technical fields such as the electronics industry or micro-systems technology requires precise forming processes for the production of small and thin components; for example, thin metal foils are being used in microelectromechanical systems, electronic components, and medical devices. In the same manner as micro bulk-metal-forming processes, metal foils with thicknesses in the range of microns are subjected to so-called size effects. Previous investigations of various metal-forming processes have shown the share of surface grains to be a decisive factor in micro foil forming behaviour. Besides this general size effect, every forming process exhibits specific size effects. In the case of bending processes, large strain gradients are present, influencing the bending parameters and process accuracy (e.g. spring-back).

In the present paper, a free bending concept is introduced, which enables the determination of size effects that occur. The mechanical properties and bending behaviour of metal foils with thicknesses ranging from 25 μm to 500 μm are discussed in terms of material properties, microstructure, and foil thickness. Fundamental experiments are performed, providing an experimental basis for future development of theoretical models to describe strain gradient-dependent forming behaviour of foil bending processes. The experimental results are compared with finite element simulations and the strain hardening behaviour is characterized by micro-indentation tests.
A dynamics-driven approach to the design of precision machine tools for micro-manufacturing and its implementation perspectives
Authors: Huo D , Cheng K
Published: March 2008

Precision machine tools are essential elements in the fabrication of high-quality micro-sized products or micro-sized features and they directly affect the machining accuracy, repeatability, and efficiency. There is a significant literature on the design of the components that constitute an industrial machine tool. However, little effort has been expended on systematically addressing the design of precision machine tools from a dynamics point of view. In this paper, the issues associated with the design of precision machine tools are presented with particular emphasis being placed on dynamic aspects as the major factors that affect the performance of the precision machine tool and the machining processes. A brief review of the design principles of precision machine tools with an emphasis on machining dynamics is presented. Then, the design processes of precision machine tools and practical modelling and simulation approaches are discussed. Case studies on the design and analysis of a fast tool servo system and a five-axis bench-top micro-milling machine are reported. The design and analysis used in the two case studies are formulated based on the proposed design methodology and guidelines.
Laser transmission welding of complex micro plastic parts
Authors: Haberstroh E , Hoffmann W-M
Published: March 2008

Only a few welding processes for plastics meet the special demands of microtechnology. Laser transmission welding has distinct advantages such as low mechanical and thermal load on the joining parts. Thus the laser is a joining tool which is particularly suitable for the welding of micro plastic parts. There are several process variants, from which contour welding enables the welding of complex and even three-dimensional weld contours. In addition, it is a very flexible process that can be easily adapted to changing part geometries. High-power diode lasers feature certain advantages such as low maintenance and investment and high efficiency, which is why they have been increasingly applied in plastics processing for welding of parts of macroscopic scale. Recent research at the Institute of Plastics Processing at RWTH Aachen University shows that it is also possible to use contour welding with high-power diode lasers to weld filigree and three-dimensional micro structures. Welding experiments with different thermoplastics show, however, that there is a strong influence of some material parameters on the laser welding process, so that some plastics are more suitable than others for the contour welding in microtechnology.
Techniques for improving surface quality after laser milling
Authors: Dobrev T , Pham D T , Dimov S S
Published: March 2008

The major drawbacks of long-pulse laser milling are the deposition of debris on the target surface and the formation of recast layers. The removal of debris becomes very important when laser milling is employed as a technology for microstructuring and especially for machining micro-cavities for a number of replication technologies. For such applications, the surface quality of the manufactured geometry becomes even more important due to the micro sizes of the machined features. A recast layer is also formed on the laser-milled surfaces. It generally consists of metal oxides and has different material properties from those of the bulk of the material. This paper discusses cleaning techniques for removing the debris, contaminations, and recast layers from micro-structures, and thus improving the surface quality of finished products. In particular, four techniques are investigated in this research: laser cleaning, ultrasonic cleaning, deoxidization (or pickling), and electrochemical polishing.