bluuebunny/crossref_metadata_2025 huggingface dataset:
Joint Production and Preventive Maintenance Strategy for Manufacturing Systems With Stochastic Demand
Authors: Jin Xiaoning , Ni Jun
Published: July 2013

This paper seeks to make joint decisions on preventive maintenance level and production quantity for manufacturing systems subject to stochastic demand in a finite-horizon. Standard models for scheduling preventive maintenance typically ignore the throughput target variation due to demand uncertainty and specify instead a constant demand rate. We show that maintenance decisions should be integrated with production decisions to accommodate the demand uncertainty. To achieve this objective, preventive maintenance (PM) flexibility is introduced as the opportunity to select and implement maintenance tasks at different levels, which can be viewed as real options to the manufacturer. PM levels can be defined according to the degree to which the machine condition is stored by maintenance. A preventive maintenance can be a minimal, imperfect, or perfect one. By leveraging PM flexibility, this paper proposes a model to determine optimal production quantity and PM level for a single-product manufacturing system with a finite planning horizon. A real option analysis (ROA) is developed to quantify the benefits and costs of PM flexibility. We derive optimal joint decisions for maintenance and production that maximize the overall expected profit of the system. We compare the proposed PM-flexible model with the conventional PM-fixed model in a case study. The results demonstrate the condition that the PM-flexible model outperforms the PM-fixed model in terms of option value (expected operating profits). We also show how the growth in demand volatility affects the optimal decisions and overall profitability. These results have important implications for making maintenance and production decisions, especially in industries that feature high demand volatility.
A Generalized Equation for Scattering Cross Section of Spherical Gas Bubbles Oscillating in Liquids Under Acoustic Excitation
Authors: Zhang Yuning
Published: July 2013

When irradiated by acoustic waves, gas bubbles can generate divergent spherical waves, which are frequently used to detect the sizes and number density of the gas bubbles. In this paper, a generalized equation for scattering cross section of spherical gas bubbles oscillating in liquids under acoustic excitation is proposed. Comparing with formulas in the literature, this generalized equation can improve the predictions of acoustical scattering cross section in the near-resonance region with high ambient pressure and above-resonance region.
Markov-Based Maintenance Planning Considering Repair Time and Periodic Inspection
Authors: Lee Seungchul , Li Lin , Ni Jun
Published: July 2013

The equipment degradation and various maintenance decision processes with unreliable machines have been studied extensively. The traditional degradation modeling using Markov process only focuses on single machine system and ignores maintenance or repair duration. This paper is devoted to analytical and numerical study of production lines within the Markov process framework considering repair time and periodic inspection. Nonexponential holding time distributions in Markov chain are approximated by inserting multiple intermediate states based on a phase-type distribution. Overall system availability is calculated by recursively solving the balance equations of the Markov process. The results show that the optimal inspection intervals for two repairable-machine systems can be achieved by means of the proposed method. By having an adequate model representing both deterioration and maintenance processes, it is also possible to obtain different optimal maintenance policies to maximize the availability or productivity for different configurations of components.
Finite Element-Based Study of the Mechanics of Microgroove Cutting
Authors: Bourne Keith A. , Kapoor Shiv G. , DeVor Richard E.
Published: July 2013

In an earlier paper, a high-speed microgroove cutting process that makes use of a flexible single-point cutting tool was presented. In this paper, 3D finite element modeling of this cutting process is used to better understand process mechanics. The development of the model, including parameter estimation and validation, is described. Validation experiments show that on average the model predicts side burr height to within 2.8%, chip curl radius to within 4.1%, and chip thickness to within 25.4%. The model is used to examine chip formation, side burr formation, and exit burr formation. Side burr formation is shown to primarily occur ahead of a tool and is caused by expansion of material compressed after starting to flow around a tool rather than becoming part of a chip. Exit burr formation is shown to occur when a thin membrane of material forms ahead of a tool and splits into two side segments and one bottom segment as the tool exits a workpiece.
Surface Energy-Controlled Self-Collapse of Carbon Nanotube Bundles With Large and Reversible Volumetric Deformation
Authors: Cheng Yuan , Maria Pugno Nicola , Shi Xinghua , Chen Bin , Gao Huajian
Published: July 2013

Molecular dynamics simulations are performed to investigate the effect of surface energy on equilibrium configurations and self-collapse of carbon nanotube bundles. It is shown that large and reversible volumetric deformation of such bundles can be achieved by tuning the surface energy of the system through an applied electric field. The dependence of the bundle volume on surface energy, bundle radius, and nanotube radius is discussed via a dimensional analysis and determined quantitatively using the simulation results. The study demonstrates potential of carbon nanotubes for applications in nanodevices where large, reversible, and controllable volumetric deformations are desired.
Thermomechanical Modeling of Scanning Joule Expansion Microscopy Imaging of Single-Walled Carbon Nanotube Devices
Authors: Song Jizhou , Lu Chaofeng , Xie Xu , Li Yuhang , Zhang Yihui , Grosse Kyle L. , Dunham Simon , Huang Yonggang , King William P. , Rogers John A.
Published: July 2013

An analytical model, validated by experiments and finite element simulations, is developed to study the thermal imaging of single-walled carbon nanotube (SWNT) devices by scanning Joule expansion microscopy (SJEM). A simple scaling law for thermal expansion at low frequencies, which only depends on two nondimensional geometric parameters, is established. Such a scaling law provides a simple way to determine the surface temperature distribution and power dissipation per unit length in an SWNT from the measured thermal expansion in experiments. The results suggest the spatial resolution of the SJEM measurement is as good as ∼50 nm.
A Numerical Investigation of Developing Flow in Concentric and Eccentric Curved Square Annuli
Authors: Nobari M. R. H. , Rajaei D.
Published: July 2013

In this article developing incompressible viscous fluid flow in concentric and eccentric curved square annuli are numerically studied. A second order finite difference method based on the projection algorithm is implemented to solve the governing equations, including the full Navier–Stokes and continuity equations in a cylindrical coordinate system. To discretize the governing equations in the square annulus, a uniform staggered grid is used to enforce an exact second order numerical scheme. The effects of the governing nondimensional parameters involving the aspect ratio, curvature, Reynolds number, Dean number, and eccentricity on the flow field, both in developing and fully developed regions of the curved annular square duct, are studied in detail. The numerical results obtained indicate that the friction factor in the eccentric curved square annulus increases with the square root of the Dean number (κ1/2) and the aspect ratio and decreases with the eccentricity. Furthermore, when the square root of the Dean number becomes larger than about 17.3, the friction factor increases linearly with the square root of the Dean number in the range of the current study.
Effect of Mesh Stiffness on the Dynamic Response of Face Gear Transmission System
Authors: Hu Zehua , Tang Jinyuan , Chen Siyu , Lei Duncai
Published: July 2013

The effect of mesh stiffness on the dynamic response of face gear transmission system combining with backlash nonlinearity is studied. First, a nonlinear time-varying (NLTV) and a nonlinear time-invariant (NLTI) dynamic models of face gear transmission system with backlash nonlinearity are formulated. The 6DOF motion equations of the face gear pair considering the mesh stiffness, backlash, contact damping and supporting stiffness are proposed. Second, the effect of mesh stiffness on the dynamic response of the face gear drive system is analyzed with the numerical method, where the mesh stiffness is expressed in two patterns as time-varying form and time-invariant form. According to the comparative study, some significant phenomena as bifurcation, chaos, tooth separation and occurrence of multijump are detected. The results show that different forms of mesh stiffness generate an obvious change on the dynamic mesh force.
Atomic layer etching removal of damaged layers in a contact hole for low sheet resistance
Authors: Kim Jong Kyu , Cho Sung Il , Lee Sung Ho , Kim Chan Kyu , Min Kyung Suk , Yeom Geun Young
Published: July 2013

A damaged layer remains on silicon substrates after high-aspect-ratio contact (HARC) etching when using a fluorocarbon gas. Atomic layer etching (ALET) is a technique that can be applied to remove the damaged layer of silicon, removing about 1.36 Å per etch cycle. The characteristics of contact damage removal by ALET are investigated and compared with the conventional damage removal technique of low-power CF4 plasma etching. The low-power CF4 plasma etching technique not only has inadequate etch depth control, but also introduces secondary damage by implanting impurities about 25 Å into the contact bottom of the silicon surface. However, ALET allows contact damage to be removed effectively without introducing secondary damage to the substrate, and with precision etch depth control at the angstrom scale. When ALET is applied subsequent to low-power CF4 plasma etching, the fluorine- and carbon-damaged silicon is effectively removed in about 10 cycles. The sheet resistance of HARC etched silicon decreases from 142 to 137 Ω/◻ after using low-power CF4 plasma etching, and subsequent ALET treatment further decreases the sheet resistance to 129 Ω/◻, which is close to the reference value of 124 Ω/◻.
Molecular Typing of CTX-M-Producing Escherichia coli Isolates from Environmental Water, Swine Feces, Specimens from Healthy Humans, and Human Patients
Authors: Hu Yan-Yan , Cai Jia-Chang , Zhou Hong-Wei , Chi Dan , Zhang Xiao-Fei , Chen Wei-Liang , Zhang Rong , Chen Gong-Xiang
Published: July 2013

CTX-M-producing
Escherichia coli
is the predominant type of extended-spectrum β-lactamase (ESBL)-producing
E. coli
worldwide. In this study, molecular typing was conducted for 139 CTX-M-producing
E. coli
isolates, phenotypically positive for ESBLs, isolated from environmental water, swine, healthy humans, and hospitalized patients in Hangzhou, China. The antibiotic resistance profiles of the isolates for the cephalosporins and fluoroquinolones were determined. The isolates showed 100% resistance to cefotaxime and ceftriaxone while maintaining relatively high susceptibility to cefoxitin, cefepime, and ceftazidime. A total of 61.9% (86/139) of the isolates, regardless of origin, showed high resistance to fluoroquinolones. PCRs and DNA sequencing indicated that
bla
CTX-M-14
was the most prevalent CTX-M-9 group gene and that
bla
CTX-M-15
and
bla
CTX-M-55
were the dominant CTX-M-1 group genes. Isolates from all sources with CTX-M types belonging to the CTX-M-1 or CTX-M-9 group were most frequently associated with epidemics. Molecular homology analysis of the isolates, conducted by phylogenetic grouping, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST), demonstrated that the dominant clones belonged to B2-ST131, D-ST648, D-ST38, or A-CC10. These four sequence types (STs) were discovered in
E. coli
isolates both from humans and from environmental water, suggesting frequent and continuous intercompartment transmission between humans and the aquatic environment. Seven novel sequence types were identified in the current study. In conclusion, this study is the first to report the molecular homology analysis of CTX-M-producing
E. coli
isolates collected from water, swine, and healthy and hospitalized humans, suggesting that pathogens in the environment might originate both from humans and from animals.
Antimicrobial Resistance in Indicator Escherichia coli Isolates from Free-Ranging Livestock and Sympatric Wild Ungulates in a Natural Environment (Northeastern Spain)
Authors: Navarro-Gonzalez N. , Porrero M. C. , Mentaberre G. , Serrano E. , Mateos A. , Domínguez L. , Lavín S.
Published: July 2013

Antimicrobial resistance was assessed in indicator
Escherichia coli
isolates from free-ranging livestock and sympatric wild boar (
Sus scrofa
) and Iberian ibex (
Capra pyrenaica
) in a National Game Reserve in northeastern Spain. The frequency of antimicrobial resistance was low (0% to 7.9%). However, resistance to an extended-spectrum cephalosporin and fluoroquinolones was detected.
Functional Characterization of Core Components of the Bacillus subtilis Cyclic-Di-GMP Signaling Pathway
Authors: Gao Xiaohui , Mukherjee Sampriti , Matthews Paige M. , Hammad Loubna A. , Kearns Daniel B. , Dann Charles E.
Published: July 2013

Bis-(3′-5′)-cyclic dimeric GMP (c-di-GMP) is an intracellular second messenger that regulates adaptation processes, including biofilm formation, motility, and virulence in Gram-negative bacteria. In this study, we have characterized the core components of a c-di-GMP signaling pathway in the model Gram-positive bacterium
Bacillus subtilis
. Specifically, we have directly identified and characterized three active
d
i
g
uanylate
c
yclases, DgcP, DgcK, and DgcW (formerly YtrP, YhcK, and YkoW, respectively), one active c-di-GMP
p
hospho
d
i
e
sterase, PdeH (formerly YuxH), and a cyclic-
d
i
g
uanylate (c-di-GMP)
r
eceptor, DgrA (formerly YpfA). Furthermore, elevation of c-di-GMP levels in
B. subtilis
led to inhibition of swarming motility, whereas biofilm formation was unaffected. Our work establishes paradigms for Gram-positive c-di-GMP signaling, and we have shown that the concise signaling system identified in
B. subtilis
serves as a powerful heterologous host for the study of c-di-GMP enzymes from bacteria predicted to possess larger, more-complex signaling systems.
Integrated flat detector CT and live fluoroscopic-guided external ventricular drain placement within the neuroangiography suite
Authors: Fiorella David , Peeling Lissa , Denice Christine M , Sarmiento Marily , Woo Henry H
Published: July 2013

Purpose

To demonstrate the feasibility of the application of integrated flat detector (FD) CT and fluoroscopic guidance (iGuide) for the placement of external ventricular drains (EVD) within the neuroangiography suite.

Methods

A retrospective review of a prospectively maintained endovascular database identified six patients who underwent EVD placement using iGuide. Patient characteristics, operator, number of passes, accuracy of placement, immediate and delayed periprocedural complications and radiation exposure were assessed.

Results

Five patients with subarachnoid hemorrhage and one patient with a large cerebellar infarct (average age 45.5 years (range 39–53), four women) underwent EVD placement within the angiography suite using iGuide. Four procedures were performed by a neuroradiologist and two by a neurosurgeon. All catheters were placed with a single pass and all terminated within the frontal horn of the ipsilateral lateral ventricle. No parenchymal or intraventricular hemorrhages were encountered after catheter placement. No patients experienced any immediate or delayed periprocedural complications. Radiation exposure related to the FD CTs required for placement was 593.7 mGy (range 539–673).

Conclusions

EVD placement under combined CT and fluoroscopic control within the neuroangiography suite is feasible. The technique predictably allows optimized EVD catheter placement with a single pass. We propose that this technique could improve the accuracy, and potentially reduce the complications, of EVD insertion in cerebrovascular patients.
Providing a genitourinary medicine colposcopy service
Authors: Sonnex C
Published: July 2013

Between 15 and 30 years ago, the management of women with abnormal cervical cytology fell within the remit of GU Medicine. This involved performing colposcopy. With the introduction of certification for colposcopists in 1998, most GU Medicine clinicians stopped providing a colposcopy service. As certification is not required for using the colposcope to diagnose and manage other ano-genital conditions, a GU Medicine-based colposcopy service was introduced at Addenbrooke's Hospital, Cambridge, UK, to assess young women with post-coital bleeding (PCB). One of the objectives of this study was to review this service. In 2011, local guidelines were implemented advising referral to the department of GU Medicine for women under the age of 40 years presenting with PCB with or without inter-menstrual bleeding (IMB) and with no history of previous cervical pathology. A case note review was undertaken for 357 consecutive patients to document clinical findings and management and to determine whether this was an appropriate route of referral. Cervical pathology was found to be uncommon and easily treated within the GU Medicine setting. The provision of a colposcopy service by GU Medicine nurse practitioners or doctors is achievable but requires appropriate training. Importantly, once obtained, these skills can be easily and usefully transferred to examining the vulva, penis, anus and anal canal.
Outward stabilization of the voltage sensor in domain II but not domain I speeds inactivation of voltage-gated sodium channels
Authors: Sheets Michael F. , Chen Tiehua , Hanck Dorothy A.
Published: July 2013

To determine the roles of the individual S4 segments in domains I and II to activation and inactivation kinetics of sodium current ( INa) in NaV1.5, we used a tethered biotin and avidin approach after a site-directed cysteine substitution was made in the second outermost Arg in each S4 (DI-R2C and DII-R2C). We first determined the fraction of gating charge contributed by the individual S4's to maximal gating current (Qmax), and found that the outermost Arg residue in each S4 contributed ∼19% to Qmaxwith minimal contributions by other arginines. Stabilization of the S4's in DI-R2C and DII-R2C was confirmed by measuring the expected reduction in Qmax. In DI-R2C, stabilization resulted in a decrease in peak INaof ∼45%, while its peak current-voltage ( I-V) and voltage-dependent Na channel availability (SSI) curves were nearly unchanged from wild type (WT). In contrast, stabilization of the DII-R2C enhanced activation with a negative shift in the peak I-V relationship by −7 mV and a larger −17 mV shift in the voltage-dependent SSI curve. Furthermore, its INadecay time constants and time-to-peak INabecame more rapid than WT. An explanation for these results is that the depolarized conformation of DII-S4, but not DI-S4, affects the receptor for the inactivation particle formed by the interdomain linker between DIII and IV. In addition, the leftward shifts of both activation and inactivation and the decrease in Gmaxafter stabilization of the DII-S4 support previous studies that showed β-scorpion toxins trap the voltage sensor of DII in an activated conformation.
The loss of sustained Ca2+signaling underlies suppressed endothelial nitric oxide production in preeclamptic pregnancies: implications for new therapy
Authors: Krupp Jennifer , Boeldt Derek S. , Yi Fu-Xian , Grummer Mary A. , Bankowski Anaya Heather A. , Shah Dinesh M. , Bird Ian M.
Published: July 2013

Approximately 8% of pregnancies are complicated by preeclampsia (PE), a hypertensive condition characterized by widespread endothelial dysfunction. Reduced nitric oxide (NO) output in PE subjects has been inferred but not directly measured, and there is little understanding of why this occurs. To address this we have used direct imaging of changes in intracellular Ca2+concentration ([Ca2+]i) and NO in umbilical vein endothelium of normal and PE subjects that is still intact and on the vessel luminal surface. This was achieved by dissection and preloading with fura 2 and DAF-2 imaging dyes, respectively, before subsequent challenge with ATP (100 μM, 30 min). As a control to reveal the content of active endothelial nitric oxide synthase (eNOS) per vessel segment, results were compared with a maximal stimulus with ionomycin (5 μM, 30 min). We show for the first time that normal umbilical vein endothelial cells respond to ATP with sustained bursting that parallels sustained NO output. Furthermore, in subjects with PE, a failure of sustained [Ca2+]ibursting occurs in response to ATP and is associated with blunted NO output. In contrast, NO responses to maximal [Ca2+]ielevation using ionomycin and the levels of eNOS protein are more similar between groups than the responses to ATP. When the endothelial cells from PE subjects are isolated and allowed to recover in culture, they regain the ability under fura 2 imaging to show multiple [Ca2+]ibursts otherwise seen in the cells from normal subjects. Thus novel clinical therapy aimed at restoring function in vivo may be possible.
Harnessing Our Very Life
Authors: Wills Peter R. , Williams David L. F. , Trussell Denys , Mann L. R. B.
Published: July 2013

The Aristotelian ideas of nature (physis) and technology (techné) are taken as a starting point for understanding what it would mean for technology to be truly living. Heidegger's critique of the conflation of scientific and technological thinking in the current era is accepted as demonstrating that humanity does not have a deep enough appreciation of the nature of life to harness its essence safely. Could the vision of harnessing life be realized, which we strongly doubt, living technology would give selected humans transforming powers that could be expected to exacerbate, rather than solve, current global problems. The source of human purposefulness, and hence of both technology and ethics, is identified in nature's emergent capability to instantiate informational representations in material forms. Ethics that are properly grounded in an appreciation of intrinsic value, especially that of life, demand that proposals to give humanity the capabilities of living technology address the social, political, economic, and environmental problems inherent in its development and potential deployment. Before any development is embarked on, steps must be taken to avoid living technology, whatever the term eventually designates, becoming available for destructive or antisocial purposes such as those that might devastate humanity or irrevocably damage the natural world.
Spectacles in the Muslim World
Authors: Mazor Amir , Abbou Hershkovits Keren
Published: July 2013

Obscurity surrounds not only the date and name of the inventor of eyeglasses, but also the date and place where eyeglasses (or information pertaining to them) reached the Muslim world. It is assumed that eyeglasses were transmitted to the Muslim world through commerce with Italian traders, which is probable, while other options also present themselves. This paper shows, at any rate, that the date traditionally given for the first acquaintance of the Muslim world with eyeglasses is wrong. In this article, we present evidence that eyeglasses were available in Syria since the fourteenth century and discuss the implications of this discovery.
Aerosol Replenishment and Cloud Morphology: A VOCALS Example
Authors: Jiang Qingfang , Wang Shouping
Published: July 2013

The impact of aerosol replenishment in a stratocumulus-topped boundary layer (STBL) on cloud morphology and albedo is examined using a large-eddy simulation (LES) model in conjunction with a prey–predator-type dynamical model following Koren and Feingold. In both the LES and the prey–predator models, the aerosol replenishment is represented as a relaxation term toward an ambient aerosol concentration with a time scale . The LESs suggest the existence of three distinct cloud regimes corresponding to different aerosol relaxation times. Specifically, for a small , the simulations are characterized by a large aerosol concentration, weak precipitation, relatively thick cloud depth, and closed cells. For a moderate , the simulated clouds exhibit open cellular patterns, in accordance with low aerosol concentration and moderate precipitation that oscillates in time. For a large , the aerosol may be depleted by intense drizzling and accordingly the cloud disappears. The critical aerosol relaxation times that separate these regimes vary with the ambient aerosol number concentration and cloud depth. Solutions from the low-order dynamical model with parameters relevant to the LESs are in general consistent with the LES results and provide further insight into the interplay among clouds, aerosol, and precipitation.
An Empirical Analysis of the Impact of Recruitment Patterns on RDS Estimates among a Socially Ordered Population of Female Sex Workers in China
Authors: Yamanis Thespina J. , Merli M. Giovanna , Neely William Whipple , Tian Felicia Feng , Moody James , Tu Xiaowen , Gao Ersheng
Published: July 2013

Respondent-driven sampling (RDS) is a method for recruiting “hidden” populations through a network-based, chain and peer referral process. RDS recruits hidden populations more effectively than other sampling methods and promises to generate unbiased estimates of their characteristics. RDS’s faithful representation of hidden populations relies on the validity of core assumptions regarding the unobserved referral process. With empirical recruitment data from an RDS study of female sex workers (FSWs) in Shanghai, we assess the RDS assumption that participants recruit nonpreferentially from among their network alters. We also present a bootstrap method for constructing the confidence intervals around RDS estimates. This approach uniquely incorporates real-world features of the population under study (e.g., the sample’s observed branching structure). We then extend this approach to approximate the distribution of RDS estimates under various peer recruitment scenarios consistent with the data as a means to quantify the impact of recruitment bias and of rejection bias on the RDS estimates. We find that the hierarchical social organization of FSWs leads to recruitment biases by constraining RDS recruitment across social classes and introducing bias in the RDS estimates.
Elevated Triglycerides Levels in Two Infants With Hypoxic‐ischemic Encephalopathy Undergoing Therapeutic Hypothermia and Receiving Parenteral Nutrition
Authors: Ting Joseph Y. , Manhas Deepak , Innis Sheila M. , Albersheim Susan
Published: July 2013

Therapeutic hypothermia has been widely applied to improve the survival/neurodevelopmental outcomes among infants with moderate‐to‐severe hypoxic ischemic encephalopathy (HIE). Due to their critical condition and concerns over feeding tolerance, it is not uncommon to withhold enteral feeds and provide parenteral nutrition (PN) during hypothermia and early rewarming. Here we report 2 infants with HIE undergoing therapeutic hypothermia, and receiving PN, who exhibited early elevated triglyceride levels. Hypertriglyceridemia can be associated with neurologic complications, ranging from altered mental status, or irritability to seizures. Given the possible altered lipid metabolism under hypothermic conditions, we advocate close monitoring of lipid tolerance and conducting further prospective trials to elucidate lipid metabolism in these infants.
Vibration analysis of axially moving line supported functionally graded plates with temperature-dependent properties
Authors: Asadi Hamed , Aghdam Mohammad M , Shakeri Mahmoud
Published: July 2013

Vibration analysis of axially moving functionally graded plates with internal line supports and temperature-dependent properties is investigated using harmonic differential quadrature method. The plate is subjected to static in-plane forces while out-of-plane loading is dynamic. Stability of an axially moving plate, traveling at a constant velocity between different supports and experiencing small transverse vibrations are considered. The series of internal rigid line supports parallel to the plate edges are considered together with various arbitrary combinations of boundary conditions. Material properties of the plate are assumed temperature-dependent which is a non-linear function of temperature and differ continuously through thickness according to a power-law distribution of the volume fractions of the plate constituents. Two types of micromechanical models, namely, the Voigt and Mori–Tanaka models are considered. Based on the classical plate theory, the governing equations are obtained for functionally graded plate using the Hamilton’s principle. In the frame of a general dynamic analysis, it is shown that the onset of instability takes place in the form of divergence. The plate may experience divergence or flutter instability at a super critical velocity. Results for dynamic analysis of isotropic and laminated plates are validated with available data in the existing literature, which show excellent agreement. Furthermore, some new results are presented for vibration analysis of functionally graded material plates to study effects of the location of line supports, material properties, volume fraction, temperature, loading, aspect ratio and speed.
Beyond What and Why
Authors: Zollo Maurizio , Cennamo Carmelo , Neumann Kerstin
Published: July 2013

In this article, we strive to contribute to the ongoing shift in the sustainability debate from its historical focus on definitional (“what”) and motivational (“why”) questions to the understanding of change and learning process questions (“how”) connected to the efforts some firms are making to evolve toward “sustainable enterprise” models. A conceptual framework to study these evolutionary processes is thus developed, and the complexities and research design trade-offs facing the related empirical inquiry highlighted. The main message advanced herein is that shifting the focus of analysis to the level of the initiatives undertaken to change the various elements in the enterprise model could prove the best way to frame the conceptual and empirical challenge before us. In a way, to make progress on the “what,” research should focus on the “how.”
Reboot cinema
Authors: Tryon Chuck
Published: July 2013

This article addresses digital three dimensions (3D) by aligning it with the industrial strategy of the reboot. On the one hand, studios seek to create textual novelty by restarting blockbuster franchises through a return to the characters’ origins. On the other hand, studios, hardware manufacturers, and theater owners – often led by technological auteurs such as James Cameron and Peter Jackson – have embraced a strategy of technological novelty by seeking to upgrade the moviegoing experience. Both forms of novelty reinforce each other and, in turn, promote what is described as a new form of storytelling that should be understood as a ‘reboot cinema.’
Construction of small RNA-mediated gene regulatory networks in the roots of rice (Oryza sativa)
Authors: Ma Xiaoxia , Shao Chaogang , Wang Huizhong , Jin Yongfeng , Meng Yijun
Published: July 2013

Background

The root systems play essential roles for plants to anchorage to the soil, and to exploit the mineral and water resources. The molecular mechanisms underlying root development have been extensively studied to improve root system architecture, especially for the crops. Several microRNA (miRNA) families have been demonstrated to be involved in plant root development. However, whether the other small RNA (sRNA) species, which occupy a dominant portion of the plant endogenous sRNA population, possess potential roles in root development remains unclear.

Results

In this study, by using sRNA high-throughput sequencing data, we made a comparison of the sRNA accumulation levels between the rice root tips and the whole roots. The sRNAs highly accumulated in the root tips and in the whole roots were extracted respectively. After Argonaute 1 (AGO1) enrichment analysis, the sRNAs with great potential of performing target cleavages were included for target prediction and degradome sequencing data-based validation. As a result, lists of the targets regulated by the AGO1-enriched sRNAs were obtained for both the root tips and the whole roots. Further evidences were identified from microarray data of the target genes to support some of the sRNA—target interactions. Specifically, the expression patterns of certain target genes in the root tips and the whole roots were contrary to those of the regulating sRNAs. Besides, several targets were indicated to play important roles in root development based on literature mining.

Conclusions

Taken together, the regulatory networks mediated by the sRNAs highly accumulated in the root tips or in the whole roots could advance our current understanding of the sRNA-involved molecular mechanisms underlying rice root development. And, the sRNA—target lists could serve as the basis for further functional investigations.
Twenty-one new sequence markers for population genetics, species delimitation and phylogenetics in wall lizards (Podarcis spp.)
Authors: Pereira Carolina , Couto Alvarina , Luís Carla , Costa Diogo , Mourão Sofia , Pinho Catarina
Published: July 2013

Background

Wall lizards of genus Podarcis are abundant and conspicuous reptiles inhabiting Europe and North Africa. In recent years, they have become a popular lizard model for phylogeographical and evolutionary ecology studies. However a lack of suitable nuclear markers currently presents a limitation on analyses of molecular evolution within this genus. We address this limitation by developing twenty-one new primer pairs for polymerase chain reaction (PCR) amplification and sequencing of anonymous sequence markers in Podarcis vaucheri and performed an assay of their cross-amplification and polymorphism levels in two closely- (P. bocagei and P. liolepis) and two distantly-related (P. muralis and P. tiliguerta) congeners.

Findings

Cross-amplification and sequencing was straightforward among members of the Iberian and North-African group within genus Podarcis (which includes P. vaucheri), and somewhat less successful in species belonging to other groups (one and four loci out of 21 failed to amplify in P. muralis and P. tiliguerta, respectively, and overall success rates were lower). Nucleotide diversity for the five species examined ranged from 0.35% to 3.5%, with an average of 1.5% across all loci. Insertion and deletion polymorphisms were found in all but three loci.

Conclusions

Given the high cross-amplification rates, these markers constitute a valuable addition to set of genomic resources available for Podarcis, especially in studies dealing with phylogenetics, species delimitation, population genetics and phylogeography.
Unreciprocated “Reverence”: “Papers,” Political Recognition, and Tlingit Engagement with US Governmentality in the Late Nineteenth Century
Authors: Langdon Steve J.
Published: July 2013

Writing and “papers” were first encountered by the Tlingit through contacts with European explorers and traders in the late eighteenth century. Euro-American traders subsequently developed a system of papers of introduction for high-ranking indigenous leaders. These papers became objects of great importance to the leaders, who held them closely and brought them out to show to other important Euro-American visitors. After 1867, US military officers observed that when they encountered Tlingit leaders, they were regularly shown papers from traders in exceptional condition. US military commanders adopted the system, and provided Tlingit leaders with papers recognizing their position and authority, which were likewise carefully preserved. This essay contends that papers of introduction and recognition were conceptualized by Tlingit leaders with the “reverence” accorded in traditional cultural practice to at.óow, thereby instantiating a hybrid bridge of relationship rooted in Tlingit conceptualization of reciprocal and sustained respect for the claims of others. The reverence bestowed by the Tlingit on these instruments was not reciprocated by later agents of US governmentality, notably Governor John Brady, and Tlingit efforts to sustain traditional cultural practices in regard to political leadership through mutual construction of an articulation with US governmentality were repudiated in the early 1900s.
Mixed Communities in the Russian North; Or, Why Are There No “Creoles” In Siberia?
Authors: Schweitzer Peter P. , Golovko Evgeniy V. , Vakhtin Nikolai B.
Published: July 2013

This article deals with “Old-Settler” communities in northeastern Siberia that were founded by Russian settlers in the course of the seventeenth century. Left to their own devices by a distant colonial administration, many of them married native women and adopted local subsistence techniques and other elements of spiritual and material culture. These processes led to the emergence of new group identities, that is to communities that distinguished themselves both from Russians and from native groups. The article provides a brief history of such communities in northern Siberia, to set the regional context, before characterizing the three study communities as experienced by the authors during fieldwork in the late 1990s. In addition, we will briefly introduce the case of the Alaskan Creoles for comparative purposes, to contrast colonial regimes and attitudes to “ethnic mixing.” This will enable us to return to the title question and to reverse it, that is, to focus on the factors that led to the emergence of Creole status in Alaska. We will argue that changing colonial policies of the Russian state need to be taken into account in order to understand why there were no Creoles in Siberia.
“A Class of People Admitted to the Better Ranks”: The First Generation of Creoles in Russian America, 1810s–1820s
Authors: Smith-Peter Susan
Published: July 2013

This article argues that the creation of a creole estate in early nineteenth-century Russian America was motivated by cultural rather than racial concerns. Creoles were the offspring of Russian or indigenous men and native women. An analysis of the earliest known list of creoles allows the author to examine the social structure of the new creole class and to note that there was a high degree of social stratification within the estate.
Myeloperoxidase modulates human platelet aggregation via actin cytoskeleton reorganization and store-operated calcium entry
Authors: Gorudko Irina V. , Sokolov Alexey V. , Shamova Ekaterina V. , Grudinina Natalia A. , Drozd Elizaveta S. , Shishlo Ludmila M. , Grigorieva Daria V. , Bushuk Sergey B. , Bushuk Boris A. , Chizhik Sergey A. , Cherenkevich Sergey N. , Vasilyev Vadim B. , Panasenko Oleg M.
Published: July 2013

Myeloperoxidase (MPO) is a heme-containing enzyme released from activated leukocytes into the extracellular space during inflammation. Its main function is the production of hypohalous acids that are potent oxidants. MPO can also modulate cell signaling and inflammatory responses independently of its enzymatic activity. Because MPO is regarded as an important risk factor for cardiovascular diseases associated with increased platelet activity, we studied the effects of MPO on human platelet functional properties. Laser scanning confocal microscopy was used to reveal carbohydrate-independent MPO binding to human platelet membrane. Adding MPO to platelets did not activate their aggregation under basal conditions (without agonist). In contrast, MPO augmented agonist-induced platelet aggregation, which was not prevented by MPO enzymatic activity inhibitors. It was found that exposure of platelets to MPO leads to actin cytoskeleton reorganization and an increase in their elasticity. Furthermore, MPO evoked a rise in cytosolic Ca2+ through enhancement of store-operated Ca2+ entry (SOCE). Together, these findings indicate that MPO is not a direct agonist but rather a mediator that binds to human platelets, induces actin cytoskeleton reorganization and affects the mechanical stiffness of human platelets, resulting in potentiating SOCE and agonist-induced human platelet aggregation. Therefore, an increased activity of platelets in vascular disease can, at least partly, be provided by MPO elevated concentrations.
The Dynamic Advertising Effect of Collegiate Athletics
Authors: Chung Doug J.
Published: July 2013

I measure the spillover effect of intercollegiate athletics on the quantity and quality of applicants to institutions of higher education in the United States—an effect popularly known as the “Flutie effect.” I treat athletic success as a stock of goodwill that decays over time, similar to that of advertising. A major challenge is that privacy laws prevent us from observing information about the applicant pool. I overcome this challenge by using order statistic distribution to infer applicant quality from information on enrolled students. Using a flexible random-coefficients aggregate discrete choice model that accommodates heterogeneity in preferences for school quality and athletic success, as well as an extensive set of school fixed effects to control for unobserved quality in athletics and academics, I estimate the impact of athletic success on applicant quality and quantity. Overall, athletic success has a significant, long-term goodwill effect on future applications and quality. However, students with lower-than-average SAT scores tend to have a stronger preference for athletic success, whereas students with higher SAT scores have a greater preference for academic quality. Furthermore, the decay rate of athletics' goodwill is significant only for students with lower SAT scores, suggesting that the goodwill created by intercollegiate athletics resides more extensively with lower-scoring students than with their higher-scoring counterparts. But, surprisingly, athletic success impacts applications even among academically stronger students.
Determinants of representation: an empirical assessment of the UK civil service
Authors: Andrews Rhys , Ashworth Rachel
Published: July 2013

In this article, we evaluate workforce diversity in the United Kingdom civil service by investigating the organisational determinants of the representation of women, black and minority ethnic and disabled people in central government departments. To do so, we draw on workforce data for 21 departments between 2007 and 2009. Our study reveals the presence of statistically significant variations in rates of representation across departments and that key organisational characteristics, such as size, administrative, part-time and temporary employment, and autonomy account for a sizeable portion of this variation but often affect under-represented groups differently. Theoretical and practical implications are discussed.
Repoliticising and redemocratising local democracy and the public realm: why we need councillors and councils
Authors: Copus Colin , Sweeting David , Wingfield Melvin
Published: July 2013

There has been a gradual decline in the status of local government within the English governance framework as a result of central unwillingness to see it as either local or government. The centre has been aided in the depoliticising of local government by literature which minimises, ignores or seeks to remove any element of the political from local government. The paper reviews the process by which local government has been delocalised and depoliticised in the English context. It goes on to suggest a new settlement between the localities and the centre and the way in which a ‘localised polity’ may emerge.
Zeolites in Mafic Pyroclastic Rocks from the Sandikli-Afyonkarahisar Region, Turkey
Authors: Ozpinar Yahya , Semiz Baris , Schroeder Paul A.
Published: July 2013

Geologic mapping and crystal-chemical analysis of Middle-Upper Miocene volcanics in the Sandıklı-Afyonkarahisar region of Turkey, coupled with published zeolite analyses has revealed that western Turkey hosts unique zeolitic mineral assemblages with distinct paragenetic sequences. The present investigation focused on pyroclastic deposits, including low to intermediate potassic trachytic/trachyandesitic tuffs (LPT) and high potassic tephriphonolitic, tephritic, and trachybasaltic tuffs (HPT), each of which contains various styles of zeolites. Optical petrography, X-ray powder diffraction, and chemical analyses have revealed varying degrees of lithification, probably related to differences in initial emplacement temperature, depositional mechanism and thickness, chilling rate, and extent of mafic composition. Zeolitization was further influenced by meteoric flushing in a hydrologically open system. Chabazite in the LPT from the Selçik area occurs extensively as coatings and infillings of pores. Phillipsite in the HPT found in the Ballık, Küfeke, and Ömerkuyu areas dominates the assemblage and is accompanied by chabazite and minor amounts of analcime. Analcime was probably generated by alteration of leucite which is found as a pyrogene mineral. Alkali zeolites or Ca-bearing zeolites formed as a consequence of the addition of Ca and/or the removal of Na (i.e. dissolution of analcime). The paragenetic sequence may be described as: analcime/phillipsite → chabazite → calcite. The characterization of these assemblages may lead to better exploitation strategies for natural zeolitic resources in the region.
Structure Determination of Trimethylsulfoxonium-Exchanged Vermiculite
Authors: Johns Candice A. , Martos-Villa Rubén , Guggenheim Stephen , Sainz-Díaz C. Ignacio
Published: July 2013

The structure of trimethylsulfoxonium-exchanged vermiculite has been examined to compare it with other onium-exchanged structures, such as tetramethylammonium- and tetramethylphosphonium-exchanged vermiculite. The three organic cations are tetrahedral in shape, but trimethylsulfoxonium [(CH3)3SO+] has an oxygen atom replacing a methyl group at one apex. This study describes the effect this substitution and the larger S atom have on the site location in the interlayer and the effect on the vermiculite 2:1 layer. These clay minerals may be commercially useful as adsorbents.

Na-exchanged crystals of vermiculite from Santa Olalla, Spain, were intercalated with trimethylsulfoxonium [Me3SO+ = (CH3)3SO+] molecules by refluxing in an aqueous 0.25 M trimethylsulfoxonium iodide solution at 80°C for 14 days. The resulting Me3SO+-exchanged vermiculite crystals were studied by single-crystal, X-ray diffraction methods and by computer modeling (density functional theory). Cell parameters are a = 5.349(2), b = 9.270(3), c = 13.825(8) Å, and β = 97.40(4)°, the space group is C2/m, and the polytype is 1M. Refinement results (R = 0.073, wR = 0.080) show that in the average structure of C2/m, the S atoms of the Me3SO+ molecules form two partially occupied planes [2.066(2) Å from each basal oxygen plane] between the 2:1 layers, and the S atoms show considerable positional disorder. The O atom of the Me3SO+ molecule occurs in the central plane of the interlayer, as far away from each 2:1 layer as possible. In projection down the c* axis, the Me3SO+ molecule resides within the center of the silicate rings from each adjacent 2:1 layer. In the ideal (static) model of the Me3SO+-exchanged vermiculite structure, the Me3SO+ molecule is oriented such that two methyl groups point toward charge-deficient bridging oxygen atoms of the basal plane; thus, the organic pillars charge compensate the bridging oxygen atoms of the 2:1 layer that are charge deficient. In projection, the oxygen atom of the Me3SO+ molecule projects over a tetrahedron containing Si. Computer modeling showed that if H2O is not included in the model, the Me3SO+ molecule (S and O atoms) is in the center of the interlayer, but with the addition of randomly placed H2O, two partially occupied planes similar to the X-ray derived model are formed.