bluuebunny/crossref_metadata_2025 huggingface dataset:
Recruitment in Retractor Bulbi Muscle During Eyeblink Conditioning: EMG Analysis and Common-Drive Model
Authors: Lepora N. F. , Porrill J. , Yeo C. H. , Evinger C. , Dean P.
Published: August 2009

To analyze properly the role of the cerebellum in classical conditioning of the eyeblink and nictitating membrane (NM) response, the control of conditioned response dynamics must be better understood. Previous studies have suggested that the control signal is linearly related to the CR as a result of recruitment within the accessory abducens motoneuron pool, which acts to linearize retractor bulbi muscle and NM response mechanics. Here we investigate possible recruitment mechanisms. Data came from simultaneous recordings of NM position and multiunit electromyographic (EMG) activity from the retractor bulbi muscle of rabbits during eyeblink conditioning, in which tone and periocular shock act as conditional and unconditional stimuli, respectively. Action potentials (spikes) were extracted and classified by amplitude. Firing rates of spikes with different amplitudes were analyzed with respect to NM response temporal profiles and total EMG spike firing rate. Four main regularities were revealed and quantified: 1) spike amplitude increased with response amplitude; 2) smaller spikes always appeared before larger spikes; 3) subsequent firing rates covaried for spikes of different amplitude, with smaller spikes always firing at higher rates than larger ones; and 4) firing-rate profiles were approximately Gaussian for all amplitudes. These regularities suggest that recruitment does take place in the retractor bulbi muscle during conditioned NM responses and that all motoneurons receive the same command signal (common-drive hypothesis). To test this hypothesis, a model of the motoneuron pool was constructed in which motoneurons had a range of intrinsic thresholds distributed exponentially, with threshold linearly related to EMG spike amplitude. Each neuron received the same input signal as required by the common-drive assumption. This simple model reproduced the main features of the data, suggesting that conditioned NM responses are controlled by a common-drive mechanism that enables simple commands to determine response topography in a linear fashion.
Activity-Dependent Modulation of Glutamatergic Signaling in the Developing Rat Dorsal Horn by Early Tissue Injury
Authors: Li Jie , Walker Suellen M. , Fitzgerald Maria , Baccei Mark L.
Published: August 2009

Tissue injury in early life can produce distinctive effects on pain processing, but little is known about the underlying neural mechanisms. Neonatal inflammation modulates excitatory synapses in spinal nociceptive circuits, but it is unclear whether this results directly from altered afferent input. Here we investigate excitatory and inhibitory synaptic transmission in the rat superficial dorsal horn following neonatal hindlimb surgical incision using in vitro patch-clamp recordings and test the effect of blocking peripheral nerve activity on the injury-evoked changes. Surgical incision through the skin and muscle of the hindlimb at postnatal day 3 (P3) or P10 selectively increased the frequency, but not amplitude, of glutamatergic miniature excitatory postsynaptic currents (mEPSCs) recorded 2–3 days after injury, without altering miniature inhibitory postsynaptic current frequency or amplitude at this time point. Meanwhile, incision at P17 failed to affect excitatory or inhibitory synaptic function at 2–3 days postinjury. The elevated mEPSC frequency was accompanied by increased inward rectification of evoked α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)–mediated currents, but no change in AMPAR/ N-methyl-d-aspartate receptor ratios, and was followed by a persistent reduction in mEPSC frequency by 9–10 days postinjury. Prolonged blockade of primary afferent input from the time of injury was achieved by administration of bupivacaine hydroxide or tetrodotoxin to the sciatic nerve at P3. The increase in mEPSC frequency evoked by P3 incision was prevented by blocking sciatic nerve activity. These results demonstrate that increased afferent input associated with peripheral tissue injury selectively modulates excitatory synaptic drive onto developing spinal sensory neurons and that the enhanced glutamatergic signaling in the dorsal horn following neonatal surgical incision is activity dependent.
On the Origin of Event-Related Potentials Indexing Covert Attentional Selection During Visual Search
Authors: Cohen Jeremiah Y. , Heitz Richard P. , Schall Jeffrey D. , Woodman Geoffrey F.
Published: August 2009

Despite nearly a century of electrophysiological studies recording extracranially from humans and intracranially from monkeys, the neural generators of nearly all human event-related potentials (ERPs) have not been definitively localized. We recorded an attention-related ERP component, known as the N2pc, simultaneously with intracranial spikes and local field potentials (LFPs) in macaques to test the hypothesis that an attentional-control structure, the frontal eye field (FEF), contributed to the generation of the macaque homologue of the N2pc (m-N2pc). While macaques performed a difficult visual search task, the search target was selected earliest by spikes from single FEF neurons, later by FEF LFPs, and latest by the m-N2pc. This neurochronometric comparison provides an empirical bridge connecting macaque and human experiments and a step toward localizing the neural generator of this important attention-related ERP component.
Quantitative in situ X-ray diffraction analysis of early hydration of Portland cement at defined temperatures
Authors: Hesse C. , Goetz-Neunhoeffer F. , Neubauer J. , Braeu M. , Gaeberlein P.
Published: August 2009

Investigation into the early hydration of Portland cement was performed by in situ X-ray diffraction (XRD). Technical white cement was used for the XRD analysis on a D5000 diffractometer (Siemens). All diffraction patterns of the in situ measurement which were recorded up to 22 h of hydration at defined temperatures were analyzed by Rietveld refinement. The resulting phase composition was transformed with respect to free water and C-S-H leading to the total composition of the cement paste. The hydration reactions can be observed by dissolution of clinker phases as well as by the formation of the hydrate phases ettringite and portlandite. With increasing temperatures the reactions proceed faster. The formation of ettringite is directly influenced by the rate of dissolution of anhydrite and tricalcium aluminate (C3A). The beginning of the main period of hydration is marked by the start of portlandite formation. The experiments point out that a quantitative phase analysis of the cement hydration is feasible with standard laboratory diffractometers.
Determination of activation energy of intermixing in textured metal-metal multilayer films via two-dimensional X-ray diffraction
Authors: Rodriguez Mark A. , Adams David P. , Tissot Ralph G.
Published: August 2009

Activation energies for the intermixing reaction of textured metal-metal multilayer thin films have been determined using X-ray diffraction analysis. Kinetic data were collected utilizing an area detector so as to reduce intensity bias from changes in out-of-plane texture during the intermixing reaction. Activation energies for Al/Pt, Ni/Ti, and Co/Al metal-metal multilayer thin films have been determined as 95.4(2) kJ/mol, 201(13) kJ/mol, and 247(19) kJ/mol, respectively.
Synchrotron XRF analyses of element distribution in fossilized sauropod dinosaur bones
Authors: Dumont M. , Zoeger N. , Streli C. , Wobrauschek P. , Falkenberg G. , Sander P. M. , Pyzalla A. R.
Published: August 2009

Sauropod dinosaurs were typically one magnitude larger than any other living or extinct terrestrial animal. This sheer size of the sauropod leads to scale effects in their biology and physiology that still are inadequately understood. The only remnants of the sauropods are their fossilized bones. These fossilized bones have sustained burial for some hundred million years and thus may have experienced significant diagenetic changes. These diagenetic changes often do not affect bone preservation on the histological level, but may lead to significant alterations of the bone microstructure. Here the influence of diagenesis on the microstructure of fossilized sauropod bones using femur cross section of Brachiosaurus brancai that was excavated in the Tendaguru beds in Tanzania is investigated. The element distribution in this dinosaur bone is studied by a combination of micro-X-ray-fluorescence (μ-XRF) using synchrotron radiation and energy dispersive X-ray analyses (EDX) in the scanning electron microscope. These techniques reveal quantitative values of the element concentration at a macroscopic level combined with qualitative information at high spatial resolution of the distribution of Ca, Co, Cr, V, Pb, U, Sr, Y, and As in the fossil bones. This allows a differentiation between the remnants of the original bone apatite and pore filling minerals and also a visualization of damage, e.g., cracks introduced by diagenetic processes.
Application of two-dimensional XRD for the characterization of the microstructure of self-leveling compounds
Authors: Seifert Severin , Neubauer Juergen , Goetz-Neunhoeffer Friedlinde , Motzet Hubert
Published: August 2009

The two-dimensional XRD (GADDS) was used to characterize the microstructure of an applied self-leveling compound (SLC). A calcium aluminate cement based SLC was prepared on two different substrates (water absorbent and nonwater absorbent) to determine the vertical distribution of the crystalline phases. The application of the GADDS enables the detection of the phase composition of the hydrating mortar in horizontal slices. Thus the analysis could be carried out in position-sensitive mode at three different areas: near the bottom, in the center, and at the top of the mortar. For investigation of SLCs from the very early hydration stage up to 10 h of hydration, a custom-made in situ sample holder for the measurements was designed and constructed. The combination of the GADDS and the custom-made in situ sample holder provides the possibility to characterize additionally the time-dependent phase composition within the SLC. The nonabsorbent substrate has no effect on the hydration of the binder phases but the absorbent substrate influences the formation of ettringite. In the top layer of the SLC the ettringite content is reduced during the first hours of hydration. The absorbing forces of the substrate lead to migration of the mix water to the substrate. This lack of water results in the reduced formation of ettringite.
Effect of residual stresses on fatigue strength of severely surface deformed steels by shot peening
Authors: Akiniwa Yoshiaki , Kimura Hidehiko , Sasaki Takeo
Published: August 2009

The compressive stress distribution below the specimen surface of severely surface deformed steels by shot peening was investigated by using laboratory X-rays and high-energy X-rays from a synchrotron radiation source, SPring-8 in the Japan Synchrotron Radiation Research Institute. Medium carbon steel plates were heat treated in two different conditions. The Vickers hardness of materials A and B after heat treatment is 408 and 617 HV, respectively. The specimens were shot peened with fine cast iron particles of the size of 50 μm. The coverage was selected to be 5000%. For the synchrotron radiation, by using the monochromatic X-ray beam with several energy levels, the stress values at the arbitrary penetration depth were measured by the constant penetration depth method. The shot-peened specimens were fatigued under four-point bending. The improvement of fatigue strength of material A was not so large because of large surface roughness. On the other hand, for material B, the surface roughness was smaller and the fatigue strength was higher than that of ground specimens.
Residual stress determination in surface treated alumina samples applying beam limiting masks
Authors: Manns Thorsten , Rothkirch André , Scholtes Berthold
Published: August 2009

This paper deals with the implementation of a theoretically described method to determine residual stresses in real space directly by means of small gauge volumes. For this purpose, beam limiting masks were designed, manufactured, and investigated in first experiments. Image series taken with a position sensitive CCD camera demonstrate the ability to detect interferences from gauge volumes beneath the sample surface by defined slit geometries. The experiments show that due to the highly absorbing masks the amount of detectable photons is poor, and thus long exposure times are necessary to receive suitable data. For increasing measurement depths (altering masks) a decrease in the intensity can be detected which leads to the assumption that the diffracted photons originate from deeper regions in the material. A model was developed to simulate the diffraction conditions with different mask layouts and material properties. Modeling yields consistent results with experimental data, and thus provides a basis for further improvements of the experimental setup and the realization and assessment of residual stress measurements.
Complementarity of experimental and numerical methods for determining residual stress states
Authors: Roy George
Published: August 2009

Residual stress states in engineering structures are usually determined by measuring components of stress tensors with depth below the material surface. There are destructive and nondestructive methods to measure strain tensor components and convert them into stress tensor components by a variety of techniques derived from constitutive (material) equations. In this study, four methods for determining the strain tensor components are presented: X-ray diffraction method (XRDM), magnetic Barkhausen noise method (MBNM), hole drilling method (HDM), and cut-and-section method (CSM); the first two are nondestructive, and the third and fourth are semidestructive and destructive, respectively. A complementarity of the experimental and two numerical methods such as boundary element method and finite element method is explained. An application of the experimental and numerical methods to measure residual stress states in an industrial component, an L-shaped part of a supporting column in a high voltage structure, is presented.
X-ray grazing incidence technique—corrections in residual stress measurement—a review
Authors: Wroński S. , Wierzbanowski K. , Baczmański A. , Lodini A. , Braham Ch. , Seiler W.
Published: August 2009

Using X-ray grazing incidence diffraction (GID) it is possible to perform a nondestructive analysis of the heterogeneous stress field for different volumes below the surface of the sample. The stress can be measured at very small depths, of the order of a few μm. The penetration depth of radiation is almost constant in a wide 2θ range for a given incidence angle α. It can be easily changed by an appropriate selection of α angle (or also by using a different type of radiation). There are, however, some factors which have to be corrected in this technique. The most important is the refraction of X-ray wave: it changes the wavelength and direction of the beam. Both effects modify a pick position. A corresponding correction was calculated and tested on ferrite powder and on 316L austenite stainless steel sample.
A Deflection‐Based Bridge Diagnosis Method
Authors: Yang Xiaofan , Zhang Chunming , Chen Weimin
Published: August 2009

By exploiting the “correlation of deflections” phenomena, we propose a new bridge diagnosis method. First, we introduce the notion of deflection correlation (DC) graphs and propose a method for building a DC graph. Second, we present a new algorithm for locating the abnormal cliques. Finally, we demonstrate the potential utility of the new method by applying it to the simulated diagnosis of a real‐life bridge.
Divalent Cu, Cd, and Pb Biosorption in Mixed Solvents
Authors: Al-Qunaibit M. H.
Published: August 2009

Dead dried Chlorella vulgaris was studied in terms of its performance in binding divalent copper, cadmium, and lead ions from their aqueous or 50% v/v methanol, ethanol, and acetone solutions. The percentage uptake of cadmium ions exhibited a general decrease with decrease in dielectric constant values, while that of copper and lead ions showed a general decrease with increase in donor numbers. Uptake percentage becomes less sensitive to solvent properties the larger the atomic radius of the biosorbed ion, and uptake of copper was the most affected. FT‐IR analyses revealed stability of the biomass in mixed solvents and a shift in vibrations of amide(I) and (II), carboxylate, glucose ring, and metal oxygen upon metal binding in all media. ΔνCOO values (59–69 cm−1) confirmed bidentate metal coordination to carboxylate ligands. The value of νasCOO increased slightly upon Cu, Cd, and Pb biosorption from aqueous solutions indicating lowering of symmetry, while a general decrease was noticed in mixed solvents pointing to the opposite. M–O stretching frequencies increased unexpectedly with increase in atomic mass as a result of solvent effect on the nature of binding sites. Lowering polarity of the solvent permits variations in metal‐alga bonds strengths; the smaller the metal ion, the more affected.
On Some Fractional Stochastic Integrodifferential Equations in Hilbert Space
Authors: Ahmed Hamdy M.
Published: August 2009

We study a class of fractional stochastic integrodifferential equations
considered in a real Hilbert space. The existence and uniqueness of the Mild solutions
of the considered problem is also studied. We also give an application for stochastic
integropartial differential equations of fractional order.
Evaluation of Defects in Multilayer Carbon Fibre Epoxy for Aeronautics Applications
Authors: Buonsanti M. , Cacciola M. , Calcagno S. , Megali G. , Morabito F. C. , Pellicanò D. , Versaci M.
Published: August 2009

Production of carbon fibre reinforced polymers is an elaborate process unfree from faults and problems. Problems during the manufacturing, such as plies′ overlapping, can cause flaws in the resulting material, so compromising its integrity. Compared with metallic materials, carbon epoxy composites show a number of advantages. Within this framework, ultrasonic tests are effective to identify the presence of defects. In this paper a Finite Element Method approach is proposed for evaluating the most effective incidence angle of an ultrasonic probe with regard to defects′ identification. According to our goal, the analysis has been carried out considering a single‐line plane emitting source varying the probe angle of inclination. The proposed model looks promising to specially emphasize the presence of delaminations as well as massive breaking in a specimen of multilayer carbon fibre epoxy. Subsequently, simulation parameters and results have been exploited and compared, respectively, for a preliminary experimental in‐lab campaign of measurements with encouraging results.
Decay Heat Removal in GEN IV Gas‐Cooled Fast Reactors
Authors: Cheng Lap-Yan , Wei Thomas Y. C.
Published: August 2009

The safety goal of the current designs of advanced high‐temperature thermal gas‐cooled reactors (HTRs) is that no core meltdown would occur in a depressurization event with a combination of concurrent safety system failures. This study focused on the analysis of passive decay heat removal (DHR) in a GEN IV direct‐cycle gas‐cooled fast reactor (GFR) which is based on the technology developments of the HTRs. Given the different criteria and design characteristics of the GFR, an approach different from that taken for the HTRs for passive DHR would have to be explored. Different design options based on maintaining core flow were evaluated by performing transient analysis of a depressurization accident using the system code RELAP5‐3D. The study also reviewed the conceptual design of autonomous systems for shutdown
decay heat removal and recommends that future work in this area should be focused on the potential for Brayton cycle DHRs.
Modeling and Simulations of Collapse Instabilities of Microbeamsdue to Capillary Forces
Authors: Ouakad Hassen M. , Younis Mohammad I.
Published: August 2009

We present modeling and analysis for the static behavior and collapse instabilities of doubly‐clamped and cantilever microbeams subjected to capillary forces. These forces can be as a result of a volume of liquid trapped underneath the microbeam during the rinsing and drying process in fabrication. The model considers the microbeam as a continuous medium, the capillary force as a nonlinear function of displacement, and accounts for the mid‐plane stretching and geometric nonlinearities. The capillary force is assumed to be distributed over a specific length underneath the microbeam. The Galerkin procedure is used to derive a reduced‐order model consisting of a set of nonlinear algebraic and differential equations that describe the microbeams static and dynamic behaviors. We study the collapse instability, which brings the microbeam from its unstuck configuration to touch the substrate and gets stuck in the so‐called pinned configuration. We calculate the pull‐in length that distinguishes the free from the pinned configurations as a function of the beam thickness and gap width for both microbeams. Comparisons are made with analytical results reported in the literature based on the Ritz method for linear and nonlinear beam models. The instability problem, which brings the microbeam from a pinned to adhered configuration is also investigated. For this case, we use a shooting technique to solve the boundary‐value problem governing the deflection of the microbeams. The critical microbeam length for this second instability is also calculated.
Two Adults with Adrenal Myelolipoma and 21-Hydroxylase Deficiency
Authors: Nermoen Ingrid , Følling Ivar , Vegge Kjetil , Larmo Arne , Nedrebø Bjørn Gunnar , Husebye Eystein Sverre , Løvås Kristian
Published: August 2009

We present incidentally discovered adrenal myelolipomas in two adult males with untreated congenital adrenal hyperplasia (CAH). The patients had simple virilizing form of CAH due to mutations in theCYP21gene coding for 21-hydroxylase; one was heterozygous for the I172N mutation and the other compound heterozygous for the I172N and I2splice mutations. The masses were not removed since myelolipomas are considered benign tumors, and the tumor size did not increase during four- and nine-year observation periods. An adrenal myelolipoma is an important exception to the rule that large tumours should be removed. Untreated CAH with prolonged excessive ACTH stimulation might contribute to the growth of adrenal masses. CAH should be considered as a differential diagnosis of patients with adrenal masses or adrenal myelolipomas.
Job Matters
Authors: Grebel Thomas , Schumm Julia
Published: August 2009

Background—

Percutaneous aortic valve replacement (PAVR) for aortic stenosis is an attractive alternative to operative valve replacement. Several devices are evaluated, but their efficacy and safety are critically discussed. An interdisciplinary approach with collaboration of cardiac surgeons and cardiologists is widely requested. We analyzed how cardiologists and cardiac surgeons assess the possibilities and risks of PAVR and whether there are substantial differences between the judgments of these 2 groups.

Methods and Results—

Fifty-one cardiologists and 54 cardiac surgeons from German hospitals completed an online questionnaire consisting of 11 questions dealing with typical risks and benefits of PAVR. Answers to all questions differed significantly between surgeons and cardiologists. Risks as impaired hemodynamic outcome, paravalvular leakage, or embolic events were deemed higher for PAVR than for an operation from both groups, but cardiologists rated those risks significantly lower than cardiac surgeons (
P
<0.01 for all questions). A regression analysis with a latent variable approach for possible advantages of PAVR (like minor operative trauma, faster recovery, less pain) showed that the fact of being a cardiologist has a significant impact on the rating of PAVR advantages (
r
=0.719,
P
<0.01), whereas personal experience showed no significant effect.

Conclusions—

Cardiologists and cardiac surgeons agree on possible risks and advantages of PAVR, but the extent differs significantly between the 2 groups. Cardiologists have a far more optimistic view of PAVR and are likely to favor an interventional approach. More and better evidence based information may help to overcome group related prejudices.
Sociodemographic and Clinical Characteristics Are Not Clinically Useful Predictors of Refill Adherence in Patients With Hypertension
Authors: Steiner John F. , Ho P. Michael , Beaty Brenda L. , Dickinson L. Miriam , Hanratty Rebecca , Zeng Chan , Tavel Heather M. , Havranek Edward P. , Davidson Arthur J. , Magid David J. , Estacio Raymond O.
Published: August 2009

Background—

Although many studies have identified patient characteristics or chronic diseases associated with medication adherence, the clinical utility of such predictors has rarely been assessed. We attempted to develop clinical prediction rules for adherence with antihypertensive medications in 2 healthcare delivery systems.

Methods and Results—

We performed retrospective cohort studies of hypertension registries in an inner-city healthcare delivery system (n=17 176) and a health maintenance organization (n=94 297) in Denver, Colo. Adherence was defined by acquisition of 80% or more of antihypertensive medications. A multivariable model in the inner-city system found that adherent patients (36.3% of the total) were more likely than nonadherent patients to be older, white, married, and acculturated in US society, to have diabetes or cerebrovascular disease, not to abuse alcohol or controlled substances, and to be prescribed fewer than 3 antihypertensive medications. Although statistically significant, all multivariate odds ratios were 1.7 or less, and the model did not accurately discriminate adherent from nonadherent patients (C statistic=0.606). In the health maintenance organization, where 72.1% of patients were adherent, significant but weak associations existed between adherence and older age, white race, the lack of alcohol abuse, and fewer antihypertensive medications. The multivariate model again failed to accurately discriminate adherent from nonadherent individuals (C statistic=0.576).

Conclusions—

Although certain sociodemographic characteristics or clinical diagnoses are statistically associated with adherence to refills of antihypertensive medications, a combination of these characteristics is not sufficiently accurate to allow clinicians to predict whether their patients will be adherent with treatment.
Two‐Dimensional Problem of Generalized Magneto‐Thermoelasticity with Temperature Dependent Elastic Moduli for Different Theories
Authors: Othman Mohamed I.A. , Lotfy Kh.
Published: August 2009

under the effect of temperature dependent properties is established. The modulus of elasticity is taken as a linear function on reference temperature. The formulation is applied under three theories of the generalized thermoelasticity: Lord‐Shulman and Green‐Naghdi (of type II) without energy dissipation, as well as the coupled theory. The normal mode analysis is used to obtain the expressions for the temperature, displacement components and the thermal stresses distributions. Numerical results are illustrated graphically for each problem considered. A Comparison is made with the results predicted by the three theories in the presence and absence of magnetic field and with the case where the modulus of elasticity is independent of temperature.
Studies on Magnetoelectric Effect for Magneto‐Electro‐Elastic Cylinder using Finite Element Method
Authors: Daga Atul , Ganesan N. , Shankar K.
Published: August 2009

In this paper, a semi‐analytical finite element formulation is presented to study the magnetoelectric (ME) effect for a multilayered and multiphase magneto‐electro‐elastic (MEE) cylinder under various boundary conditions. Numerical studies are done to evaluate the ME coefficient for different thickness ratio of piezoelectric phase in the multilayered composite. Studies are also done for the evaluation of ME coefficient for different volume fractions of piezoelectric phase in the multiphase composite. Ansys 8.1 is used to validate the present formulation using thermal analogy concept.
Anisotropic Poroelastic Hollow Cylinders with Damaged Periphery under Harmonic Axial Loading: Relevance to Bone Remodelling
Authors: Nguyen V.H. , Lemaire T. , Naili S.
Published: August 2009

An anisotropic modelling of hollow porous cylinders under harmonic axial loading is proposed to simulate the in vivo behavior of structural elements of cortical bone called osteons. The peripheral surface of the medium is supposed to be impermeable, except on possible existing cracks. Numerical tests are performed by analytical and finite element methods based on the Biot poroelastic theory. The influence of microcracks on the fluid flow is numerically investigated. The findings show that the existence of peripheral cracks directly modifies the stimulation of the mechano‐sensitive network of the bone. Thus, this study attempts to propose a likely mechanism by which bone can sense changes of the surrounding mechanical environment.
Application of Analytical Hierarchy Process (AHP) and Sensitivity Analysis for Selecting the Best Design Concepts during Conceptual Design Stage
Authors: Hambali A. , Sapuan S.M. , Ismail N. , Nukman Y.
Published: August 2009

Selection of the design concepts is one of the significant activities in product development process. Most of the products are usually failed due to inappropriate decision during the selection of the design concepts at the early stage of product development process. The determination of the greatest selection of design concepts at the conceptual design stage is a crucial decision due to a poor design concept which can never be compensated for by a good detailed design and it will implicate great expense of redesign cost. Analytical Hierarchy Process (AHP) is one available method in forming a systematic approach for a single decision maker or a group decision maker, is employed to solve such problem. In this paper, 7 design concepts of wheelchair designs were considered as a case study. The AHP through utilizing Expert Choice software was implemented to determine the most suitable design concept of wheelchair design at the conceptual design stage. The sensitivity analysis was performed to test the stability of the priority ranking and to increase the confidence in the selection of design concepts.
Optimal Design for a Thermosyphon Solar Water Heater Convenient for Malaysia
Authors: Zahedi H.R. , Adam N.M. , Sapuan S.M. , Ahmad M.M.H.M.
Published: August 2009

A thermosyphon solar water heating system with in‐tank auxiliary electric heater has been simulated according Malaysian hot water consumption profile using TRNSYS simulation program. The optimum value of a parameter is defined as the value which maximized the annual solar fraction of the system. This paper has a good deal of information concerning sizing of common components of thermosyphon solar water heater operated under certain condition (load volume, distribution profile and temperature). The results indicate that collector should be tilted at Ø + (→ 7° 37°) for all collector areas. Vertical storage tank has better performance in tropical climate (The average annual solar fraction for vertical was 88% and for horizontal was 82.9%).
Regimes of the North Australian Wet Season
Authors: Pope Mick , Jakob Christian , Reeder Michael J.
Published: August 2009

The variability of the north Australian wet season is examined by performing cluster analysis on the wind and thermodynamic information contained in the 2300 UTC radiosonde data at Darwin for 49 wet seasons (September–April) from 1957/58 to 2005/06. Five objectively derived regimes of the wet season are obtained and are found to differ significantly in their synoptic environment, cloud patterns, and rainfall distributions. One regime is primarily associated with the trade wind regime. Two regimes are associated with the lead up to and break periods of the monsoon at Darwin. A fourth regime is clearly identified with the active monsoon at Darwin and is offered as a definition of monsoon onset. This regime captures the active monsoon environment associated with significant widespread rainfall. The fifth regime is a mixed regime, with some days associated with the inactive monsoon, a period of westerly zonal winds at Darwin associated with relatively suppressed convection compared with the active monsoon. Other days for this regime are break period conditions with a low-level westerly flow below 900 hPa.
Simulations of the 2004 North American Monsoon: NAMAP2
Authors: Gutzler D. S. , Long L. N. , Schemm J. , Roy S. Baidya , Bosilovich M. , Collier J. C. , Kanamitsu M. , Kelly P. , Lawrence D. , Lee M.-I. , Sánchez R. Lobato , Mapes B. , Mo K. , Nunes A. , Ritchie E. A. , Roads J. , Schubert S. , Wei H. , Zhang G. J.
Published: August 2009

The second phase of the North American Monsoon Experiment (NAME) Model Assessment Project (NAMAP2) was carried out to provide a coordinated set of simulations from global and regional models of the 2004 warm season across the North American monsoon domain. This project follows an earlier assessment, called NAMAP, that preceded the 2004 field season of the North American Monsoon Experiment. Six global and four regional models are all forced with prescribed, time-varying ocean surface temperatures. Metrics for model simulation of warm season precipitation processes developed in NAMAP are examined that pertain to the seasonal progression and diurnal cycle of precipitation, monsoon onset, surface turbulent fluxes, and simulation of the low-level jet circulation over the Gulf of California. Assessment of the metrics is shown to be limited by continuing uncertainties in spatially averaged observations, demonstrating that modeling and observational analysis capabilities need to be developed concurrently. Simulations of the core subregion (CORE) of monsoonal precipitation in global models have improved since NAMAP, despite the lack of a proper low-level jet circulation in these simulations. Some regional models run at higher resolution still exhibit the tendency observed in NAMAP to overestimate precipitation in the CORE subregion; this is shown to involve both convective and resolved components of the total precipitation. The variability of precipitation in the Arizona/New Mexico (AZNM) subregion is simulated much better by the regional models compared with the global models, illustrating the importance of transient circulation anomalies (prescribed as lateral boundary conditions) for simulating precipitation in the northern part of the monsoon domain. This suggests that seasonal predictability derivable from lower boundary conditions may be limited in the AZNM subregion.
Regional, Seasonal, and Diurnal Variations of Extreme Convection in the South Asian Region
Authors: Romatschke Ulrike , Medina Socorro , Houze Robert A.
Published: August 2009

Temporal and spatial variations of convection in South Asia are analyzed using eight years of Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) data and NCEP reanalysis fields. To identify the most extreme convective features, three types of radar echo structures are defined: deep convective cores (contiguous 3D convective echo ≥40 dBZ extending ≥10 km in height) represent the most vertically penetrative convection, wide convective cores (contiguous convective ≥40 dBZ echo over a horizontal area ≥1000 km2) indicate wide regions of intense multicellular convection, and broad stratiform regions (stratiform echo contiguous over an area ≥50 000 km2) mark the mesoscale convective systems that have developed the most robust stratiform regions.

The preferred locations of deep convective cores change markedly from India’s east coast in the premonsoon to the western Himalayan foothills in the monsoon. They form preferentially in the evening and over land as near-surface moist flow is capped by dry air aloft. Continental wide convective cores show a similar behavior with an additional nocturnal peak during the monsoon along the Himalayan foothills that is associated with convergence of downslope flow from the Himalayas with moist monsoonal winds at the foothills. The oceanic wide convective cores have a relatively weak diurnal cycle with a midday maximum. Convective systems exhibiting broad stratiform regions occur primarily in the rainiest season and regions—during the monsoon, over the ocean upstream of coastal mountains. Their diurnal patterns are similar to those of the wide convective cores.
A High-Resolution Coupled Riverine Flow, Tide, Wind, Wind Wave, and Storm Surge Model for Southern Louisiana and Mississippi. Part II: Synoptic Description and Analysis of Hurricanes Katrina and Rita
Authors: Dietrich J. C. , Bunya S. , Westerink J. J. , Ebersole B. A. , Smith J. M. , Atkinson J. H. , Jensen R. , Resio D. T. , Luettich R. A. , Dawson C. , Cardone V. J. , Cox A. T. , Powell M. D. , Westerink H. J. , Roberts H. J.
Published: August 2009

Hurricanes Katrina and Rita were powerful storms that impacted southern Louisiana and Mississippi during the 2005 hurricane season. In Part I, the authors describe and validate a high-resolution coupled riverine flow, tide, wind, wave, and storm surge model for this region. Herein, the model is used to examine the evolution of these hurricanes in more detail. Synoptic histories show how storm tracks, winds, and waves interacted with the topography, the protruding Mississippi River delta, east–west shorelines, manmade structures, and low-lying marshes to develop and propagate storm surge. Perturbations of the model, in which the waves are not included, show the proportional importance of the wave radiation stress gradient induced setup.
The Lost Cause? Examining the Southern Culture of Honor Through Defensive Gun Use
Authors: Copes Heith , Kovandzic Tomislav V. , Miller J. Mitchell , Williamson Luke
Published: August 2009

This article reconsiders the “Southern culture of honor” thesis, which has enjoyed prevalence in the social sciences since the first half of the 20th century. The bulk of researchers investigating the link among Southern residence, culture of honor, and violence have focused on attitudinal measures of violence through surveys and ethnographic experiments indicating preferences and opinions toward engaging in hypothesized violence. The current research measures respondents’ actual violent behaviors in a national survey of defensive gun use (DGU). Although the results failed to support a relationship between Southern residence and defensive gun use, respondents’ age and victimization were significant. This finding is dissonant with the historical literature that suggests that the rural Southern White male is prone to a violent defense of honor; as such, the article orients discussion around the further theoretical advancement of the culture-of-honor perspective.
Normal Accident Theory versus High Reliability Theory: A resolution and call for an open systems view of accidents
Authors: Shrivastava Samir , Sonpar Karan , Pazzaglia Federica
Published: August 2009

We resolve the longstanding debate between Normal Accident Theory (NAT) and High-Reliability Theory (HRT) by introducing a temporal dimension. Specifically, we explain that the two theories appear to diverge because they look at the accident phenomenon at different points of time. We, however, note that the debate’s resolution does not address the non-falsifiability problem that both NAT and HRT suffer from. Applying insights from the open systems perspective, we reframe NAT in a manner that helps the theory to address its non-falsifiability problem and factor in the role of humans in accidents. Finally, arguing that open systems theory can account for the conclusions reached by NAT and HRT, we proceed to offer pointers for future research to theoretically and empirically develop an open systems view of accidents.
What’s needed is application, not reconciliation: A response to Shrivastava, Sonpar and Pazzaglia (2009)
Authors: Perrow Charles
Published: August 2009

Normal accident theory says nothing about the time dimension that triggers human failures and thus is not appropriately applied by Shrivastava et al., in their article. Indeed, the theory focuses upon system aspects rather than human behavior, thus no reconciliation is needed with those that focus upon human behavior, it just more economically explains a subset of accidents.
Socially constructing safety
Authors: Turner Nick , Gray Garry C.
Published: August 2009

Social scientific perspectives on occupational safety largely characterize it as a disembodied, tangible, and easily quantifiable phenomenon. Recent research efforts have focused on exploring organizational conditions that predict occupational safety outcomes, resulting in top-down, often de-contextualized prescriptions about how to control safety in the workplace (e.g. ‘management should promote a culture of safety’). There is growing interest in how social processes of organizing, wider socio-cultural considerations, and the situated production of safety can contribute to the appreciation of the ‘lived experience’ of life and death at work. This Special Issue focuses on the socially constructed nature of occupational safety and the insight it provides in understanding broader social and organizational processes. In this article, we first describe how various social scientific disciplines share an interest in occupational safety and organizational behavior, yet rarely speak to another. We provide an overview of the five articles that comprise the Special Issue, and briefly highlight some ways forward for studying safety in organizations.
Measurement of Resting Energy Expenditure in Healthy Children
Authors: Mellecker Robin R. , McManus Alison M.
Published: August 2009

Background: The role that the components of energy expenditure play in the etiology of childhood obesity has highlighted the need for greater accuracy and standardized protocols for the measurement of resting energy expenditure (REE). However, protocols used to assess REE in children are varied, and consensus on a suitable method for measuring REE in children has not been reached. This study was undertaken to determine the effect of measurement time and measurement device (mask or mouthpiece) on REE in healthy children. Design: Following a 12‐hour fast and abstinence from exercise, 23 children (age, 7–12 years) completed two 35‐minute protocols: one with a face mask and the other with a mouthpiece/noseclip. Energy expenditure was measured continuously via indirect calorimetry, while device acceptability was assessed using a 6‐point comfort rating scale. Results: Repeated measures ANOVA indicated that there was no significant difference in REE when measured after 10, 15, 20, or 25 minutes of rest compared to 30 minutes for either the mask or mouthpiece/noseclip (REE range, 1371–1460 kcal/d). Examination of the percentage coefficient of variation (CV) in energy expenditure for each time period by device showed that the least variation existed after 20 minutes of measurement using the mask (CV 6%). Paired t test analysis indicated significantly less discomfort when wearing the mask compared to the mouthpiece/noseclip. Conclusion: It would appear that a 20‐minute protocol using a mask may increase compliance and prove to be a more practical protocol for measuring REE in children.
Merging, Masquerading and Morphing: Metaphors and the World Wide Web
Authors: Pablo Zelinna , Hardy Cynthia
Published: August 2009

We examine the role of metaphors in relation to Web-based phenomena through a comparative study of 29 Web portals, established under a World Bank project known as the Development Gateway. Our analysis suggests that three metaphors — expert, market and community — are particularly significant across these portals, either separately or in combination. The study indicates three particular ways in which these metaphors can combine — merging, masquerading and morphing. We conclude by discussing the implications of using metaphor to understand how practitioners design Web portals and how users engage with them.
Early Family Formation Among White, Black, and Mexican American Women
Authors: Landale Nancy S. , Schoen Robert , Daniels Kimberly
Published: August 2009

Using data from Waves I and III of Add Health, this study examines early family formation among 6,144 White, Black, and Mexican American women. Drawing on cultural and structural perspectives, models of the first and second family transitions (cohabitation, marriage, or childbearing) are estimated using discrete-time multinomial logistic regression. Complex differences by race and ethnicity and generation are partially explained by differences in attitudes and values in adolescence and family socioeconomic status; marriage values are especially important in first-generation Mexican women’s early entry into marriage. Examination of sequential family transitions sheds light on racial and ethnic differences in the meaning and consequences of early cohabitation and pre-union births.
How effective are physical activity interventions for alleviating depressive symptoms in older people? A systematic review
Authors: Blake H. , Mo P. , Malik S. , Thomas S.
Published: August 2009

Background: The benefits of physical exercise in reducing clinically defined depression in the general population have been established, although a review of the evidence for older adults is needed.

Objectives: To assess the efficacy of physical exercise for the treatment of depressive symptoms in older adults (>60 years).

Data sources: We searched: MEDLINE (1966—May 2008); EMBASE (1980—May 2008); Cumulative Index to Nursing & Allied Health Literature (CINAHL; 1982—May 2008); PsycINFO (1966—May 2008), The Cochrane Library (Issue 2, 2008), and National Research Register (NRR; Issue 2, 2008).

Review methods: Randomized controlled trials and quasi-experimental studies of physical exercise interventions for depression were included where 80% or more of participants were >60 years. Abstracts were assessed to determine whether they met specified inclusion criteria. Primary analysis focused on the prevalence of diagnosable depressive disorder following intervention. Secondary outcome was depression or mood scores on standardized scales.

Results: Eleven randomized controlled trials with a total of 641 participants were included in the review. Short-term positive outcome for depression or depressive symptoms was found in nine studies, although the mode, intensity and duration of intervention varied across studies. Medium- to long-term effects of intervention were less clear.

Conclusion: Physical exercise programmes obtain clinically relevant outcomes in the treatment of depressive symptoms in depressed older people. Exercise, though not appropriate for all in this population, may improve mood in this group. Further research is needed to establish medium- to long-term effects and cost-effectiveness.