bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Pre-Load on Corrosion Vulnerability of Reinforced Concrete
Authors: Vishnu J.R. , Sharma U.K.
Published: July 2012

The present study investigates the relation between loading and corrosion of reinforcing steel in reinforced concrete elements. Beam specimens of size 100 mm × 150 mm × 1200 mm were cast using three different normal and high strength concrete mixes. After 45 days of moist curing, these beams were subjected to four point bending at different loading levels. Some specimens were also subjected to cyclic flexural loads. After load tests, ponds were constructed on the tension side of these beams, and the specimens were subjected to ponding using 5% NaCl solution. Half cell potential readings were taken to monitor the time taken for corrosion initiation. After corrosion initiation, an external current was applied to these specimens to accelerate the corrosion process. The residual loading capacity of the beams was found at the end of the durability exposure tests. The results indicate that loading history and loading levels have significant effects on both corrosion initiation and corrosion propagation. The results also show that both corrosion initiation and propagation rates also depend on the type of concrete used.
Two Methods for Determining Softening Relationships of Dam Concrete and Wet-Screened Concrete
Authors: Zhao Zhifang , Zhang Jun , Zhou Hougui , Shah S.P. , Zhao Zhigang
Published: July 2012

The direct tension tests and three-point bending notched beam tests were performed on dam concrete and wet-screened concrete specimens. Based on these two fracture tests, the softening relationships (σ – w curves) of dam concrete and wet-screened concrete were determined by employing direct tension test method and inverse analysis method respectively. The inverse analysis method based on cracking strength criterion was adopted in the analysis. The results showed that the obtained softening relationships by the DT test method were in good agreement with those by the inverse analysis. It was also found that the tensile strength as well as the fracture energy of dam concrete were smaller than those of wet-screened concrete, but the crack width at zero stress of dam concrete was greater than that of wet-screened concrete. It can be seen there may be a definite relation between the softening relationship of dam concrete and that of wet-screened concrete.
An Experimental Campaign on the Long-Term Properties of Self Compacting Concrete
Authors: Mazzotti Claudio , Savoia Marco
Published: July 2012

In the present paper, the results of an experimental campaign concerning the long-term properties of self-compacting concrete are presented. Five mixes of SCC and one mix of CVC have been employed, with different compressive strength covering the range of application from cast-in-place to prestressed structures.

For each mix, compressive strength, elastic modulus and shrinkage evolution with time have been monitored. Creep tests have also been performed at different stress levels and at two ages at loading (7 and 28 days). The influence of concrete strength, stress level have been observed, together with the role played by the mix parameters. The Poisson' ratio evolution with time has been also observed; the role played by the application of long term loads and by different curing conditions on the concrete residual strength has been also investigated.

Finally, experimental data both in terms of shrinkage and creep are compared with international code provisions.
Multi-Stage Performance of Seismically Isolated Bridge Using Triple Pendulum Bearings
Authors: Malekzadeh Masoud , Taghikhany Touraj
Published: July 2012

Triple pendulum isolator (TPI) represent a new generation of adaptive friction isolation system to control super-structure demand in different hazard levels. This isolator incorporates four concave surfaces and three independent pendulum mechanisms. Pendulum stages can be set to address specific response criteria for moderate, severe and very severe events.

Herein after mathematical formulation of typical elevated highway bridge using TPI, series of nonlinear dynamic analysis were performed with different friction coefficients, pendulum radius and slider displacement capacities. Effects of variation of these parameters were investigated on key bridge demand parameters under multi hazard level excitations by using probabilistic description.
Improved Generalized Inverse Beamforming for Jet Noise
Authors: Dougherty Robert P.
Published: July 2012

The acoustic holography/generalized inverse method of microphone array processing is improved in two ways: the linear algebra is simplified to avoid separate processing of cross spectral matrix eigenvalues, and a new regularization technique is introduced to produce reasonable results when the problem is underdetermined. Model-scale testing has shown that the improved method can map coherent sources and extrapolate directivity patterns using a modest 2D nearfield array and one data acquisition in a warehouse with no acoustic treatment. Tests with shop air jets show that rectangular jets can have asymmetric radiation patterns and the flight deck and jet blast deflector dramatically alter the radiation pattern in a configuration representing an aircraft carrier launch operation.
Noise Radiation from Single and Multiple Rod Configurations
Authors: Hutcheson Florence V. , Brooks Thomas F.
Published: July 2012

Acoustic measurements were performed on single and multiple rod configurations to study the effect of Reynolds number, surface roughness, freestream turbulence, proximity and wake interference on the radiated noise. The Reynolds number ranged from 3.8 × 103 to 105. Directivity measurements were performed to determine how well the dipole assumption for the radiation of vortex shedding noise holds for the different model configurations tested. The dependence of the peak Sound Pressure Level on velocity was also examined. Several concepts for the reduction of the noise radiating from cylindrical rods were tested. It was shown that wire wraps and collar distributions could be used to significantly reduce the noise radiating from rods in tandem configurations.
Propulsion Airframe Aeroacoustic Integration Effects for a Hybrid Wing Body Aircraft Configuration
Authors: Czech Michael J. , Thomas Russell H. , Elkoby Ronen
Published: July 2012

An extensive experimental investigation was performed to study the propulsion airframe aeroacoustic effects of a high bypass ratio engine for a hybrid wing body aircraft configuration where the engine is installed above the wing. The objective was to provide an understanding of the jet noise shielding effectiveness as a function of engine gas condition and location as well as nozzle configuration. A 4.7% scale nozzle of a bypass ratio seven engine was run at characteristic cycle points under static and forward flight conditions. The effect of the pylon and its orientation on jet noise was also studied as a function of bypass ratio and cycle condition. The addition of a pylon yielded significant spectral changes lowering jet noise by up to 4 dB at high polar angles and increasing it by 2 to 3 dB at forward angles. In order to assess jet noise shielding, a planform representation of the airframe model, also at 4.7% scale was traversed such that the jet nozzle was positioned from downstream of to several diameters upstream of the airframe model trailing edge. Installations at two fan diameters upstream of the wing trailing edge provided only limited shielding in the forward arc at high frequencies for both the axisymmetric and a conventional round nozzle with pylon. This was consistent with phased array measurements suggesting that the high frequency sources are predominantly located near the nozzle exit and, consequently, are amenable to shielding. The mid to low frequency sources were observed further downstream and shielding was insignificant. Chevrons were designed and used to impact the distribution of sources with the more aggressive design showing a significant upstream migration of the sources in the mid frequency range. Furthermore, the chevrons reduced the low frequency source levels and the typical high frequency increase due to the application of chevron nozzles was successfully shielded. The pylon was further modified with a technology that injects air through the shelf of the pylon which was effective in reducing low frequency noise and moving jet noise sources closer to the nozzle exit. In general, shielding effectiveness varied as a function of cycle condition with the cutback condition producing higher shielding compared to sideline power. The configuration with a more strongly immersed chevron and a pylon oriented opposite to the microphones produced the largest reduction in jet noise. In addition to the jet noise source, the shielding of a broadband point noise source was documented with up to 20 dB of noise reduction at directivity angles directly under the shielding surface.
Hybrid Wing Body Aircraft System Noise Assessment with Propulsion Airframe Aeroacoustic Experiments
Authors: Thomas Russell H. , Burley Casey L. , Olson Erik D.
Published: July 2012

A system noise assessment of a hybrid wing body configuration was performed using NASA's best available aircraft models, engine model, and system noise assessment method. A propulsion airframe aeroacoustic effects experimental database for key noise sources and interaction effects was used to provide data directly in the noise assessment where prediction methods are inadequate. NASA engine and aircraft system models were created to define the hybrid wing body aircraft concept as a twin engine aircraft with a 7500 nautical mile mission. The engines were modeled as existing technology, in production, bypass ratio seven turbofans. The baseline hybrid wing body aircraft was assessed at 26.4 dB cumulative below the FAA Stage 4 certification level. To determine the potential for noise reduction with relatively near term technologies, seven other configurations were assessed beginning with moving the engines two fan nozzle diameters upstream of the trailing edge and then adding technologies for reduction of the highest noise sources. Aft radiated noise was expected to be the most challenging to reduce and, therefore, the experimental database focused on jet nozzle and pylon configurations that could reduce jet noise through a combination of source reduction and shielding effectiveness. The best configuration for reduction of jet noise used state-of-the-art technology chevrons with a pylon above the engine in the crown position. This configuration resulted in jet source noise reduction, favorable azimuthal directivity, and noise source relocation upstream where it is more effectively shielded by the limited airframe surface, and additional fan noise attenuation from acoustic liner on the crown pylon internal surfaces. Vertical and elevon surfaces were also assessed to add shielding effectiveness. The elevon deflection above the trailing edge showed some small additional noise reduction whereas vertical surfaces resulted in a slight noise increase. With the effects of the configurations from the database included, the best available noise reduction was 41.5 dB cumulative. Projected effects from additional technologies were assessed for an advanced noise reduction configuration including landing gear fairings and advanced pylon and chevron nozzles. Incorporating the three additional technology improvements, an aircraft noise is projected of 42.9 dB cumulative below the Stage 4 level.
A Simple Model for Study of Sound Generation Mechanism in Mixing Layers
Authors: Zhou Lin , Wei Mingjun , Sun De-Jun
Published: July 2012

Applying Lighthill's acoustic analogy equation to temporally-developing mixing layers, we derived a direct relation between the near-field dynamics, in terms of pressure work, and the far-field sound. The sound radiation predicted by the new model was compared to the direct numerical simulation result, and they agreed well in all stages of vortex dynamics development in mixing layers: roll-up, pairing, merging, saturation, and viscous damping. Using the new formulation, we explained the mechanism for sound generation from the considered flow, and depicted general topological structures for the distribution of sound sources. Though the dynamics is different for vortex roll-up and vortex pairing, the same mechanism for sound generation is suggested by similar topological structures of the sound sources defined here.
Extremum-Seeking Control of Jet Noise
Authors: Maury R. , Kœnig M. , Cattafesta L. , Jordan P. , Delville J.
Published: July 2012

An extremum-seeking algorithm is used to optimise a fluidic jet-noise controller. The control device, called a fluidevron, produces reductions in jet noise that are comparable with those achieved using conventional microjets, but the underlying flow-physics have been found to be different (Laurendeau et al. [1]). The extremum-seeking algorithm is used to optimise the control either for maximum low-frequency noise-reduction, or for maximum overall noise-reduction. This is achieved through a specification of the frequency-range over which noise reduction is sought. The extremum-seeking performs well, producing integrated low-frequency noise reduction gains on the order of 2.5 dB at 60 degrees (angle measured with respect to the dowstream jet axis) when tuned for maximum low-frequency benefit, and an overall reduction of 1.5 dB, where the high frequency penalty is virtually eliminated, when tuned for maximum spectral range. Farfield microphone spectra at different polar stations show that the control effect is omnidirectional. This implies that there is no directional bias in the response of the source mechanisms to the actuation. Finally, the relationship between noise reduction and flow-rate is studied and found to be non-linear. The source mechanisms are most receptive at low flow-rate, a saturation point being reached after which the actuation no longer has control authority over the source dynamics.
On the Power Spectra of Sound Transmitted through Turbulence
Authors: Campos L.M.B.C. , Cunha F.S.R.P.
Published: July 2012

The power spectrum of sound received from a known acoustic source after transmission through a region of turbulence is calculated by a convolution with a distortion function. The latter specifies the modification of the acoustic power spectrum as it propagates through the turbulent region. The distortion function is the Fourier transform with regard to time of the characteristic function of a bivariate aleatory process, whose random variables are the acoustic phase shifts of two neighbouring waves; the phase shifts are due to the Doppler effect of the random turbulence velocity and are a function of position and time. The turbulence spectrum is used to calculate the r.m.s. phase shift and also the correlation time in the correlation coefficient. This specifies the received power spectrum for any type of source, viz a monochromatic or tonal source, or a broadband source, e.g. Gaussian or exponential. The received power spectra depend on the choice of correlation function, e.g. Gaussian or volume conserving. The received power spectra simplify in the asymptotic case of large r.m.s. phase shift; otherwise, the exact received power spectra consists of an attenuated source spectrum plus a series of scattering broadbands. The latter demonstrate how the acoustic energy in the emitted source spectrum is spread over a wider range of frequencies by propagation through turbulence, leading to spectral broadening in the received spectrum.
A Refinement of Asymptotic Predictions and Full Numerical Solution of Helicopter Rotor Noise in the Far Field
Authors: Delale Can F. , Zafer Baha , Aslan A. Rüstem
Published: July 2012

The asymptotic analysis of Parry and Crighton [1] for propeller noise in the far field, which is based on Hanson's formulation [2] of the FW-H equation, is refined to second order by Laplace's method [3] for evaluating integrals, accounting for second order contributions near the blade tip for loading and thickness noise. The full numerical solution of Hanson's integrals for both thickness and loading noise is also presented. In particular, the theory is applied to a four-bladed helicopter rotor with tip Mach numbers ranging between 0.5 and 0.7. The aerodynamic loading in this case is obtained using a 3D compressible code based on finite volume method with intensified grid density near the blade tip. The far field angular SPL noise distributions of a helicopter rotor in hover show that the present second order asymptotic formula is in better agreement with full numerical computations than that of the first order formula, especially for thickness noise.
Augmenting Architecture through Desktop Manufacturing
Authors: Jabi Wassim
Published: July 2012

Personal desktop manufacturing, with its roots in hacker culture, is on the cusp of exploding into the main stream due to the advent of affordable personal 3D printers. This paper is an exploration of these advances in desktop manufacturing technology and their impact on our relationship with products and the built environment. The paper draws parallels to the personal computing and desktop publishing revolutions that offer clues to the future of personal desktop manufacturing. Four major themes have emerged from this exploration: Personal empowerment, remote printing and collaboration, full-scale digital construction, and, most intriguingly, architectural prosthetics. Based on an open-source philosophy and creative commons licensing, desktop manufacturing is redefining our relationship with large manufacturers and is beginning to convert us back from a consumerist culture into a creator one.
Photorealistic Computer Generated Representations as a Means of Visual Communication of Architectural Schemes in the Contemporary Culture
Authors: Bates-Brkljac Nada
Published: July 2012

This paper explores the nature and effects of photorealistic computer generated architectural representations on the perception and understanding of design schemes. The aim is to obtain an insight into potentials and limitations that arise from this form of communication. Findings suggest that by conveying a sense of lifelike presence, these representations enhance the understanding of design. They are also perceived as more realistic, accurate and comprehensible and as such, more effective means of communicating design than hand drawings. However, not all photorealistic styles are perceived as neither lifelike nor credible. Instead, it was evident that these representations enter perceptions through a complex interaction between their attribute and observers familiarity with form and visual literacy. Most importantly, the understanding of design through photorealistic representations is deeply conditioned by the prevailing cultural style of visual representation and knowledge of the preferences of specific professions.
Micro-Simulation Function to Display Textual Data in Virtual Reality
Authors: Abdelhameed Wael A.
Published: July 2012

Virtual reality creates an effective communication platform with a high degree of perception and exploration, increasing the benefits of VR applied functions. This research paper reports a virtual reality function of using the micro-simulation editor-player with XML file in the virtual reality environment. The details of the function are presented. The function aiming at combining visual and textual data in VR model visualisation, was developed by the researcher, and was included in the micro-simulation plug-in of a virtual reality program, VR Studio version 6, previously known as UC-Win/Road, by the program developers. The research paper discusses the computer simulation techniques and uses in virtual reality in general. The research paper proceeds to introduce a case study of construction process visualization in the virtual reality environment, in which the newly developed function is utilized to simultaneously visualise data reports related to the stages of VR model visualisation. The concluding remarks accentuate this micro-simulation function with its potential uses in different fields.
Sensing Touch Curtain: Soft Architecture and Augmented Communication
Authors: Davis Felecia
Published: July 2012

The Sensing Touch Curtain prototype demonstrates one type of sensing that can be woven into soft building components. It is a computational textile that senses the nearness of a person or people and registers absolute touch on fabric through capacitive sensing. Capacitive sensing measures position and distance between the textile and a target object by sending forth electric signals. The methods of construction, method of electronic weaving and ways to consider models for somatosensory textiles are discussed in the paper. The Sensing Touch project frames an expanded role for soft architecture enclosures.
Civic Media Platforms and Participatory Urbanism: A Critical Reflection
Authors: Chernyakova Irina , Villere Mariel , Casalegno Federico , Giusti Leonardo , Schladow Zoe
Published: July 2012

In this paper, we explicate our research on technology-mediated urban experience specific to two hyper-local tests in which the space of the ‘public’ is transformed into a virtual network by connective broadcasting. The first case study presents collective mapping in Rio de Janeiro toward increased civic engagement and sustainability, the second tests documentation of political demonstrations for strategic and archival purposes for Occupy Boston. Grouped under the term “participatory urbanism,” the projects intend to explore how an individual activates interstitial space (between the physical city and hovering networks, between public and private) by engaging technology and civic media to affect change in the built environment. The physical and virtual environments serve as reciprocal sources of information, engendering a collective practice of shared encounters. We investigate how such encounters of user-centered activity through mobile and web-based media support or implicate the perception and manipulation of the built environment over spans of time and locations, and will highlight qualitative elements of a mobile and web platform designed for successful civic engagement and participatory urbanism.
Architectural Sociability as a Strategy to Drive Technology Integrations into Architectural Structures and Smart Environments
Authors: Ochs Steven W.
Published: July 2012

Traditional architectural design fulfills the basic needs of society, but its influence as a system to facilitate personal connection has declined with the growth of telecommunications and social networks. The advance of interactive architecture is now positioning buildings to once again fulfill the role as facilitator of connections and fulfill our personal need of belonging. While current attempts to integrate social communication, technology with built environments are nominally effective; Architectural Sociability is proposed as an effective design solution. Strategy details include a purpose based social approach in which social networks, localized data streams, ubiquitous computing, pervasive networks, and smart environments are considered a traditional part of an architectural structure.
Methods Used to Evaluate the Hawkmoth (Manduca Sexta) as a Flapping-Wing Micro Air Vehicle
Authors: Hollenbeck Alex C. , Palazotto Anthony N.
Published: July 2012

Examining a biological flapping-flight mechanism as a mechanical system provides valuable insight related to the development and construction of Flapping-Wing Micro Air Vehicles (FWMAVs). Insects provide excellent candidates for this reverse-engineering, and one species in particular, the hawkmoth Manduca sexta, stands out as an exceptional model. Engineers with FWMAV aspirations can benefit greatly from knowledge of M.sexta's advanced yet deceptively simple flight mechanism. Avenues for investigating this mechanism include finite element modeling, nanoindentation for material properties, and mechanical power output calculations or measurement. This paper presents these concepts and reviews existing literature to provide a platform for ongoing FWMAV research and design.
Testing of Atmospheric Turbulence Effects on the Performance of Micro Air Vehicles
Authors: Lundström David , Krus Petter
Published: July 2012

Micro Air Vehicles (MAV) are generally operated at low altitudes and within the earth boundary layer. This is a very dynamic environment with varying wind intensity and turbulence levels far greater than those experienced by traditional manned aircraft cruising at higher altitudes. Yet aerodynamic research on MAVs is often based on the assumption of steady aerodynamics. Little effort has been made to experimentally determine the validity of this assumption. In this paper, the effect of turbulence on the performance of a MAV is studied using flight testing in different wind conditions. Flight testing technique, data logging equipment and data reduction are explained. Additionally, a low cost technique for propeller performance measurement is presented. Results show that the flow around a MAV flying in windy conditions qualifies as highly unsteady, although the impact on its performance is surprisingly small for the kind of turbulence levels at which MAVs can be expected to operate. Accelerometer data from the flights reveals that if steady aerodynamic theory is assumed, increasing turbulence should have resulted in a measurable drag increase, thus indicating that the tested MAV to some extent passively manages to benefit from the turbulence.
Small UAV Design Using an Integrated Design Tool
Authors: Kody Frank , Bramesfeld Goetz
Published: July 2012

A numerical design tool was developed that greatly facilitates the design process of small UAVs. The integrated approach of the method makes it highly suitable for the aerodynamic needs of such small aircraft. Traditional design tools and methodologies are typically tailored for the design of larger aircraft, such as for general aviation, whose aerodynamics generally exhibit more linear behaviors. Building on this motivation, a user friendly integrated design tool was developed and validated in order to provide a more tailored approach to designing low Reynolds number aircraft. At the heart of the tool is a performance prediction that relies on a higher-order free wake potential flow aerodynamic code that employs viscous drag corrections. Subsequently, the method provides accurate characteristics for a wide range of Reynolds numbers and aspect ratio wings. In a validation process, the flight performance results of the method are compared with the results of other prediction methods as well as with several experimental flight test results. In general good agreement exists. The utility of the integrated design tool is demonstrated with the design application of a small UAV for a heavy lift competition. The design tool greatly streamlined the design process, limiting it to two weeks rather than the typical several months.
Forecasting Water Level Fluctuations of Urmieh Lake Using Gene Expression Programming and Adaptive Neuro-Fuzzy Inference System
Authors: Karimi Sepideh , Shiri Jalal , Kisi Ozgur , Makarynskyy Oleg
Published: July 2012

Forecasting lake level at various prediction intervals is an essential issue in such industrial applications as navigation, water resource planning and catchment management. In the present study, two data driven techniques, namely Gene Expression Programming and Adaptive Neuro-Fuzzy Inference System, were applied for predicting daily lake levels for three prediction intervals. Daily water-level data from Urmieh Lake in Northwestern Iran were used to train, test and validate the used techniques. Three statistical indexes, coefficient of determination, root mean square error and variance accounted for were used to assess the performance of the used techniques. Technique inter-comparisons demonstrated that the GEP surpassed the ANFIS model at each of the prediction intervals. A traditional auto regressive moving average model was also applied to the same data sets; the obtained results were compared with those of the data driven approaches demonstrating superiority of the data driven models to ARMA.
Sea Level Anomalies in the Tropical Indian Ocean during Two Contrasting Southwest Monsoon Years
Authors: Prakash Satya , Mahesh C. , Gairola R. M.
Published: July 2012

The sea level anomalies (SLA) in the tropical Indian Ocean (TIO) during two consecutive contrasting southwest monsoon years of 2002 (deficit) and 2003 (normal) are examined using multi-satellite measurements. The rainfall anomalies over the TIO in the month of July show distinct patterns during these two years. The more consistent patterns analogous to rainfall anomalies are reflected in the freshwater flux anomalies which is one of the major contributors of the local sea level change. As a result, the SLA shows distinct features in the north Indian Ocean during these two years. The surface atmospheric convergence and divergence patterns in the TIO are also investigated using multi-satellite wind vectors which are supposed to be correlated with the southwest monsoon rainfall and a key component of sea level change. The results suggest that the eustatic effect and near surface convergence/divergence of winds have significant impact on SLA locally.
Experimental Study on Bed Load Transport of Shell Fragment-Mixed Sand under Waves
Authors: Kumagai Takahiro , Nakajima Sayaka
Published: July 2012

Beneficial use of shell for constitutive materials of beach or tidal flat is proposed instead of its disposal. Since the shape of shell fragment is oblate, the knowledge on littoral drift of sand with spherical shape could not be applied directly for understanding of its behavior under waves. In this study, critical shields number and settling velocity of shell fragment are evaluated changing oblate shapes of the fragments, and the characteristics of bed load transport of shell and shell-mixed sand beds are examined by a movable-bed experiment. From the experiments, the effects of oblateness on the increase of resistance to wave and current are elucidated. It is found that the interaction of sand and shell on their movements has an effect on the bed-load rate changing the height of sand ripples.
Differential association of microRNAs with polysomes reflects distinct strengths of interactions with their mRNA targets
Authors: Molotski Natali , Soen Yoav
Published: July 2012

While microRNAs have been shown to copurify with polysomes, their relative fraction in the translation pool (polysome occupancy) has not yet been measured. Here, we introduce a high-throughput method for quantifying polysome occupancies of hundreds of microRNAs and use it to investigate factors affecting these occupancies. Analysis in human embryonic stem cells (hESCs) and foreskin fibroblasts (hFFs) revealed microRNA-specific preferences for low, medium, or high polysome occupancy. Bioinformatics and functional analysis based on overexpression of endogenous and chimeric microRNAs showed that the polysome occupancy of microRNAs is specified by its mature sequence and depends on the choice of seed. Nuclease treatment further suggested that the differential occupancy of the microRNAs reflects interactions with their mRNA targets. Indeed, analysis of microNRA•mRNA duplexes showed that pairs involving high occupancy microRNAs exhibit significantly higher binding energy compared to pairs with low occupancy microRNAs. Since mRNAs reside primarily in polysomes, strong interactions lead to high association of microRNAs with polysomes and vice versa for weak interactions. Comparison between hESCs and hFFs data revealed that hESCs tend to express lower occupancy microRNAs, suggesting that cell type–dependent translational features may be affected by expression of a particular set of microRNAs.
Box H/ACA snoRNAs are preferred substrates for the trimethylguanosine synthase in the divergent unicellular eukaryote Trichomonas vaginalis
Authors: Simoes-Barbosa Augusto , Chakrabarti Kausik , Pearson Michael , Benarroch Delphine , Shuman Stewart , Johnson Patricia J.
Published: July 2012

The 2,2,7-trimethylguanosine caps of eukaryal snRNAs and snoRNA are formed by the enzyme Tgs1, which catalyzes sequential guanine-N2 methylations of m7G caps. Atypically, in the divergent unicellular eukaryote Trichomonas vaginalis, spliceosomal snRNAs lack a guanosine cap and the recombinant T. vaginalis trimethylguanosine synthase (TvTgs) produces only m2,7G in vitro. Here, we show by direct metabolic labeling that endogenous T. vaginalis RNAs contain m7G, m2,7G, and m2,2,7G caps. Immunodepletion of TvTgs from cell extracts and TvTgs add-back experiments demonstrate that TvTgs produces m2,7G and m2,2,7G caps. Expression of TvTgs in yeast tgs1Δ cells leads to the formation of m2,7G and m2,2,7G caps and complementation of the lethality of a tgs1Δ mud2Δ strain. Whereas TvTgs is present in the nucleus and cytosol of T. vaginalis cells, TMG-containing RNAs are localized primarily in the nucleolus. Molecular cloning of anti-TMG affinity-purified T. vaginalis RNAs identified 16 box H/ACA snoRNAs, which are implicated in guiding RNA pseudouridylation. The ensemble of new T. vaginalis H/ACA snoRNAs allowed us to predict and partially validate an extensive map of pseudouridines in T. vaginalis rRNA.
Hierarchies and the Survival of Prisoners of War During World War II
Authors: Holderness Clifford G. , Pontiff Jeffrey
Published: July 2012

Using a comprehensive database of American prisoners of war during World War II, we find that survival from captivity generally declines as the hierarchy of a prisoner's group becomes steeper or more closely matches the military's established hierarchy. There is no evidence that survival is enhanced by being held in more hierarchical groups. One interpretation of these findings that is consistent with survivors' accounts is that the military's hierarchy was too inflexible to adapt from the battlefield to captivity and this inflexibility impeded trading among the prisoners.

This paper was accepted by Brad Barber, finance.
Regional language as a tool for integration? Romanians and Valencian Catalan
Authors: Vigers Dick
Published: July 2012

Spain has witnessed substantial migratory flows in the last decade, some of which have been concentrated in autonomous regions with co-official languages. This article examines the responses of one migrant community, the Romanians, to the presence of two official languages, Castilian
and Valencian, where they work and whether the regional language (RL) can offer additional resources in the integrative process. It considers briefly the growth and specificity of Romanian migration to the Valencian region and examines the role of the discourse of Latinity in negotiating the
situation of the Romanians within the host community and the perceptions and evaluations of language competences that emerge from it. It is suggested that the migration experience, particularly as temporary and circular trajectories, and transnational modes of living foster a critical language
awareness. Ultimately, the socio-economic evaluation means that the Romanian migrants reproduce dominant language ideologies towards the co-official RL.
Hathor im Pflanzendickicht: Zum Menit des libyschen Großfürsten Ker. (Ägyptisches Museum Berlin Inv. 8939)
Authors: Moje Jan
Published: July 2012

Publication and socio-cultural analysis of a faience menit belonging to the Libyan Great Chief of the Libu and Meshwesh, Ker, from the Western Delta.
It's Alive! The Federal Booker-Fix Debate Stirs
Authors: III Frank O. Bowman,
Published: July 2012

These Editor's Observations introduce Volume 24, Number 5 of the Federal Sentencing Reporter, an issue devoted to renewed discussion in Congress and the U.S. Sentencing Commission about whether there is a need for legislative action to revise or replace the advisory federal sentencing guidelines system judicially created by the U.S. Supreme Court's 2005 decision in United States v. Booker. It describes the basic positions of the main institutional actors, briefly summarizes the articles in the issue, and makes a prediction about the likelihood of action in the near term.
Alterations of LXRα and LXRβ expression in the hypothalamus of glucose-intolerant rats
Authors: Kruse María Sol , Rey Mariana , Vega María Cristina , Coirini Héctor
Published: July 2012

Liver X receptor (LXR) α and β are nuclear receptors that are crucial for the regulation of carbohydrate and lipid metabolism. Activation of LXRs in the brain facilitates cholesterol clearance and improves cognitive deficits, thus they are considered as promising drug targets to treat diseases such as atherosclerosis and Alzheimer's disease. Nevertheless, little is known about the function and localization of LXRs in the brain. Here, we studied the expression of LXR in the brains of rats that received free access to 10% (w/v) fructose group (FG) in their beverages or water control drinks (control group (CG)). After 6 weeks rats in the FG presented with hypertriglyceridemia, hyperinsulinemia, and became glucose intolerant, suggesting a progression toward type 2 diabetes. We found that hypothalamic LXR expression was altered in fructose-fed rats. Rats in the FG presented with a decrease in LXRβ levels while showing an increase in LXRα expression in the hypothalamus but not in the hippocampus, cerebellum, or neocortex. Moreover, both LXRα and β expression correlated negatively with insulin and triglyceride levels. Interestingly, LXRβ showed a negative correlation with the area under the curve during the glucose tolerance test in the CG and a positive correlation in the FG. Immunocytochemistry revealed that the paraventricular and ventromedial nuclei express mainly LXRα whereas the arcuate nucleus expresses LXRβ. Both LXR immunosignals were found in the median preoptic area. This is the first study showing a relationship between glucose and lipid homeostasis and the expression of LXRs in the hypothalamus, suggesting that LXRs may trigger neurochemical and neurophysiological responses for the control of food intake and energy expenditure through these receptors.
A Maximum-Likelihood Method to Correct for Allelic Dropout in Microsatellite Data with No Replicate Genotypes
Authors: Wang Chaolong , Schroeder Kari B , Rosenberg Noah A
Published: July 2012

Allelic dropout is a commonly observed source of missing data in microsatellite genotypes, in which one or both allelic copies at a locus fail to be amplified by the polymerase chain reaction. Especially for samples with poor DNA quality, this problem causes a downward bias in estimates of observed heterozygosity and an upward bias in estimates of inbreeding, owing to mistaken classifications of heterozygotes as homozygotes when one of the two copies drops out. One general approach for avoiding allelic dropout involves repeated genotyping of homozygous loci to minimize the effects of experimental error. Existing computational alternatives often require replicate genotyping as well. These approaches, however, are costly and are suitable only when enough DNA is available for repeated genotyping. In this study, we propose a maximum-likelihood approach together with an expectation-maximization algorithm to jointly estimate allelic dropout rates and allele frequencies when only one set of nonreplicated genotypes is available. Our method considers estimates of allelic dropout caused by both sample-specific factors and locus-specific factors, and it allows for deviation from Hardy–Weinberg equilibrium owing to inbreeding. Using the estimated parameters, we correct the bias in the estimation of observed heterozygosity through the use of multiple imputations of alleles in cases where dropout might have occurred. With simulated data, we show that our method can (1) effectively reproduce patterns of missing data and heterozygosity observed in real data; (2) correctly estimate model parameters, including sample-specific dropout rates, locus-specific dropout rates, and the inbreeding coefficient; and (3) successfully correct the downward bias in estimating the observed heterozygosity. We find that our method is fairly robust to violations of model assumptions caused by population structure and by genotyping errors from sources other than allelic dropout. Because the data sets imputed under our model can be investigated in additional subsequent analyses, our method will be useful for preparing data for applications in diverse contexts in population genetics and molecular ecology.
Right ventricular outflow tract reconstruction in adolescents and adults after previous repair of congenital heart defects
Authors: Hartyánszky István , Székely László , Szudi László , Mihályi Sándor , Kádár Krisztina , Temesvári András , Bálint Hajnalka , Szatmári András , Tóth Attila
Published: July 2012

Due to successful surgical treatment of congenital heart defects in infants and children, the number of patients who reach the adolescent/adult age is continuously increasing. Aims: The authors sought to identify the short- and medium-term outcomes of reconstruction of right ventricular outflow tract in adolescents and adults who underwent surgical intervention for congenital heart defect in infancy or early childhood. Methods: Between 2001 and 2012, 48 patients (age: 15–39, mean 21 years) (30 tetralogy of Fallot, 11 pulmonary atresia + ventricular septal defect, 6 transposition of great arteries + ventricular septal defect + left ventricular outflow tract obstruction, and 1 truncus arteriosus) had repeat operation because of right ventricular dysfunction. All patients previously underwent right ventricular outflow tract procedures in early childhood. Results: In 31 patients, the small homograft, and in 9 patients the transannular-paths were replaced for “adult-size” homograft. Bioprosthetic pulmonary valve replacement was performed in pulmonary (6 patients) and homograft annuli (2 patients). In 14 patients, resection of the right ventricular outflow tract aneurism was also necessary to be performed. There was no early and mid-time (10 years) mortality. In 97.5% of patients with homograft-re-implantation, there was no need for repeat intervention for 5 years. Conclusions: The right ventricular outflow tract restoration in adolescents and adults is an effective procedure. The reconstruction should be performed in early adolescent period to prevent right ventricular dysfunction. The authors prefer using bioprosthetic pulmonary valve replacement in patients with adult-size pulmonary or homograft annulus. Orv. Hetil., 2012, 153, 1219–1224.
Study on Synthesis Chitosan Oligomer Stabilized Silver Nanoparticles Using Green Chemistry and Their Burn Wound Healing Effects
Authors: Kang Yun Ok , Park Won Ho
Published: July 2012

The preparation of metal nanoparticles is a major research area in technical engineering due to their unusual properties, such as catalytic activity, novel electronic, optic and magnetic properties and biotechnology. Specially, silver has been used for years in the medical field for antimicrobial applications because it known for its antimicrobial properties and even has shown to prevent HIV binding to host cells. Common synthesis, chemical and physical methods using chemical reducing agent and organic solvent are not too suitable to have application to bioengineering because they should have associated environmental toxicity or biological hazards. Development of sustainable processes through green chemistry is attractive about the elimination or minimization of chemical waste. Here, we introduce the green method for preparation of silver nanoparticles using chitosan oligomer as both reducing and stabilizing agent in water. We expect that the use of environmentally benign solvent and chitosan oligomer to prepare silver nanoparticles offers numerous benefits and compatibility for pharmaceutical and biomedical applications.
Hydrothermal synthesis of calcium-deficient hydroxyapatite whiskers and their thermal transformation to polycrystalline β-tricalcium phosphate short fibers
Authors: Zorn Katharina , Mitró Daniel , Vorndran Elke , Gbureck Uwe , Müller Frank A.
Published: July 2012

Resorbable calcium phosphate fibers are of particular interest to reinforce biodegradable bone substitutes for load-bearing applications. The aim of the present study was to prepare calcium-deficient hydroxyapatite (dHAp) whiskers with a molar Ca/P ratio of 1·5 by a hydrothermal synthesis and to transform them to β-tricalcium phosphate (β-TCP) by a subsequent thermal treatment. For the hydrothermal synthesis, calcium tripolyphosphate was used and different amounts of 2-propanol were added to adjust the pH. Average whisker lengths of 160 µm were obtained at a 2-propanol content of 27 volume-percent. However, 33% dicalcium phosphate anhydrate (DCPA) were present as a secondary phase. The amount of DCPA could be reduced by increasing the amount of 2-propanol. Whisker samples consisting of 88% dHAp and 12% DCPA were selected to investigate microstructural changes and phase transformations during thermal treatment. Polycrystalline single phase -TCP short fibers were obtained after a thermal treatment at 1125°C.
1961 Exposition in Turin, Italy: engineers take command
Authors: Chiorino Cristiana
Published: July 2012

The paper focuses on the exposition complex of Italia ’61 in Turin constructed for the centenary celebrations of the Unification of Italy in 1961 and hosting several exhibitions and an international exposition on labour. With its technical ultra-modern boldness and daring, the Italia ’61 Exposition aimed to express the new expansionist potential of the Italian economy, while at the same time leaving the city with a legacy of immediately usable infrastructures. The 1961 exposition chose, in the best tradition of universal exhibitions, to focus on the rhetoric of technological progress. Those who interpreted this message came from the professional and cultural traditions of engineering. Turin's post-war architectural culture had virtually nothing to do with the centenary exposition project, being relegated to exhibition design and hang only, the ephemeral elements of those structures. All the submitted projects conformed to the philosophy of the celebrations, which was an exaltation of expressionism in engineering. With a series of thinly disguised pedagogical intents, the exposition aimed to fulfil one of its main goals, making science and technology more accessible to all. This explains the great desire for space and constructions. Thanks to its architecture, the exposition was able to achieve these objectives. The buildings themselves made the exhibition, even more so than in the nineteenth century, literally becoming advertising hoardings.
Creating the right internal climate for the Crystal Palace
Authors: Schoenefeldt Henrik
Published: July 2012

This paper explores Joseph Paxton's experiments with climate control inside glasshouses between 1830 and 1850 and how he exploited this experience to achieve the right internal climate for the 1851 Crystal Palace in Hyde Park. The first part investigates various solutions for ventilation and the management of solar radiation, heat loss and humidity inside glass structures that Paxton had developed before his engagement at Hyde Park. It also shows how these solutions were appropriated for Hyde Park and discusses the various alternative ventilation, shading and cooling arrangements that Paxton investigated for the palace before adopting the final strategy. The final section is a brief analysis of the actual performance of the building and explores the steps taken to improve the ventilation. This post-occupancy history suggests that Paxton's previous experience was insufficient to be entirely successful for the Crystal Palace, but it provided Paxton with new insights that informed his design for the ventilation system deployed in the second Crystal Palace at Sydenham (1852–1854).