bluuebunny/crossref_metadata_2025 huggingface dataset:
Free Space Optical Communications Link Budget Estimation
Authors: Stotts Larry B. , Kolodzy Paul , Pike Alan , Graves Mr. Buzz , Daugherty Dave , Douglas Mr. Jeff
Published: April 2013

This paper describes a new methodology of estimating the free space optical communications link budgets to be expected in conditions of severe turbulence. Comparisons will be given between theory and field measurements.
New Technologies to Enable Millimeter-Wave Imaging
Authors: Mait Joseph N. , Wikner David A. , Mirotznik Mark S. , Fernandez-Cull Christy
Published: April 2013

We apply structured passive elements and computational imaging to millimeter waves to enable a mobile imager. Experimental results are presented.
An aberration-free lens with zero F-number
Authors: Schurig David
Published: April 2013

Starting from the Luneberg lens index profile, we apply the transformation design method to the problem of far-field imaging of (infinitely) distant objects. This analysis yields a single element lens with a planar image surface, zero aberrations of all orders, zero F-number and (in some cases) constant aperture for all angles of incidence [10].
Optimization of hybrid imaging systems including digital deconvolution in the presence of noise
Authors: Diaz Frédéric , Goudail François , Loiseaux Brigitte , Huignard Jean-Pierre
Published: April 2013

We address the depth of focus enhancement in hybrid imaging systems, including a phase mask and a deconvolution filter. A final image quality criterion is introduced to optimize and compare different masks.
Surveillance of Dynamic Threats in Complex Urban Environments
Authors: Eismann Michael T.
Published: April 2013

The emergence of asymmetric and terrorist threats as a prime focus of the U.S. military operations is placing high demands on Air Force reconnaissance, surveillance, and targeting systems. When placed within the context of a complex, urban landscape, a need arises for advanced electro-optical and infrared (EO/IR) sensing techniques to deal with the combination of small, diverse, and elusive targets and broad area, complex, and highly structured regions of interest. The Air Force Research Laboratory is addressing these science and technology needs through a number of research projects developing advanced EO/IR sensing concepts including hyperspectral change detection, infrared wide area surveillance, and feature-aided target tracking in complex, culturally-cluttered areas.
Single-Mode Room-Temperature CW Interband Cascade Lasers Covering the λ = 3–4 μm Spectral Band
Authors: Kim M. , Bewley W. W. , Lindle J. R. , Kim C. S. , Canedy C. L. , Abell J. , Vurgaftman I. , Meyer J. R.
Published: April 2013

Interband cascade lasers emitting at 3.6 μm operated to a maximum temperature of 335 K and produced 59 mW of cw power at room temperature. Single-mode cw emission with 12 mW of power was demonstrated.
Tunable Difference Frequency Generation Laser Spectrometers: Successes, Challenges, and Opportunities
Authors: Richter Dirk , Weibring Petter , Fried Alan , Rippe Lars , Lewander Märta , Batet Oscar , Walega James G. , Spuler Scott
Published: April 2013

We will review the state of development and applications of difference-frequency generation (DFG) based laser spectrometers to atmospheric research and discuss the unique operating conditions and techniques that enable high precision performance for ground and airborne environments.
Quartz Enhanced Photoacoustic Spectroscopy: Today and Beyond
Authors: Kosterev Anatoliy A.
Published: April 2013

Current theoretical understanding and practical applications of the trace gas sensing technique called quartz enhanced photoacoustic spectroscopy (QEPAS) will be presented. Work in progress and planned QEPAS developments will be discussed.
Real Time Determination of Water Isotope ratios by Laser Absorption Spectroscopy at 2.73 µm using Kalman Filter
Authors: Wu Tao , Chen Weidong , Kerstel Erik , Fertein Eric , Masselin Pascal , Gao Xiaoming , Koeth Johannes , Rößner Karl , Bruekner Daniela
Published: April 2013

Kalman filter was applied to measurements of water isotopologue ratios by laser spectroscopy at 2.73 µm. The results obtained in 1-s showed a 1σ precision that required ~30-s averaging when using a simple average approach.
Coherent detection schemes for ultra-sensitive molecular spectroscopy in the mid-IR
Authors: Wysocki Gerard
Published: April 2013

Different coherent detection schemes and their impact on sensitivity of mid-infrared laser spectrometers used for chemical detection will be discussed. Several example applications will be given.
Broadband high-resolution spectroscopy based on adjustable Vernier-frequency-scale sliding – application to CO2 remote sensing
Authors: Mussio L. , Hardy B. , Raybaut M. , Godard A. , Mohamed A. K. , Lefebvre M.
Published: April 2013

We present a novel method for broadband spectroscopy. Due to the entanglement of two cavities within an optical parametric oscillator, frequency resolution and span are widely adjustable. The technique is applied to CO2 remote sensing.
A Laser Sounder for global measurements of CO2 from space
Authors: Riris Haris , Abshire James , Allan Graham , Hasselbrack William , Weaver Clark , Mao Jianping
Published: April 2013

We report on airborne CO2 measurements using a fiber-based laser sounder system using the 1.57 µm band of CO2.
Sensors at ppb sensitivity or better based on multiple line integration spectroscopy techniques
Authors: Rao Gottipaty N , Karpf Andreas
Published: April 2013

Employing integrated absorption of multiple lines or summation of the absolute values of the wavelength modulation spectroscopy signals, we report sensitivities of ppb for the detection of trace gases.
Spectroscopy with shaped laser pulses
Authors: von Vacano B. , Motzkus M.
Published: April 2013

The combination of ultrabroadband laser pulses and pulse shaping techniques allows the photonic integration of functions such as excitation, probing and interferometry making sophisticated nonlinear spectroscopy like Coherent Anti-Stokes Raman scattering (CARS) extremely simple.
Infrared Time Domain Spectroscopy with Synchronized Frequency Combs
Authors: Newbury Nathan R. , Coddington Ian , Swann William C.
Published: April 2013

We describe a frequency-comb based system for time-domain spectroscopy in the near infrared. Our configuration implements synchronous, repetitive sampling of the time domain signature for real-time coherent signal averaging and improved signal-to-noise ratio.
Optical fiber setups for the improvement of chemical sensing
Authors: Bauer Christoph , Willer Ulrike , Schade Wolfgang
Published: April 2013

Recent developments on optical fibers have impact on online chemical sensing. The uses of active optical fibers for amplifying short pulses and of passive fibers which are suitable for the coupling of QC-lasers are discussed.
Ammonia sensor for environmental monitoring based on a 10.4 µm external-cavity quantum cascade laser
Authors: Lewicki Rafał , Kosterev Anatoliy , Thomazy David M. , Gong Longwen , Griffin Robert , Day Timothy , Tittel Frank
Published: April 2013

An EC-QCL based sensor employing photo-acoustic spectroscopy as a detection technique for monitoring of atmospheric ammonia will be reported. For the NH3 absorption line at 965.35 cm−1 a detection limit of 3.3 ppbv was obtained.
High Speed Imaging in Reactive Flows Using Hyperspectral Tomography and Photodissociation Spectroscopy
Authors: Ma Lin
Published: April 2013

Two techniques are discussed for high speed imaging in reactive flows: a hyperspectral tomography sensor for measuring distributions of temperature and chemical species, and a photodissociation-based diagnostic for imaging two-dimensional mixture fraction.
Optimization of an External Cavity Quantum Cascade Laser for Chemical Sensing Applications
Authors: Phillips M. C. , Bernacki B. E. , Taubman M. S. , Cannon B. D. , Schiffern J. T. , Myers T. L.
Published: April 2013

We describe and characterize an external cavity quantum cascade laser designed for detection of multiple airborne chemicals, and used with a compact astigmatic Herriott cell for sensing of acetone and hydrogen peroxide.
Nd:YAG-CO2 Double-Pulse LIBS for Explosives Detection
Authors: Weidman Matthew , Baudelet Matthieu , Sigman Michael E. , Dagdigian Paul J. , Richardson Martin
Published: April 2013

A double-pulse Nd:YAG-CO2 LIBS scheme was applied to the analysis of an organic film of polystyrene and also tested on 2,4,6-TNT residues. Different behaviors in atomic and molecular signals are interpreted and discussed for discrimination applications.
Snapshot spectral imaging using birefringent interferometry and image replication
Authors: Gorman Alistair , Muyo Gonzalo , Harvey Andrew Robert
Published: April 2013

A snapshot multi-spectral imaging technique is described which employs cascaded birefringent interferometers to simultaneously project multiple spectral images onto a single detector array. Example images are also shown.
New Approaches for Evaluating Lidar-Derived Shoreline
Authors: Parrish Christopher E. , White Stephen A. , Calder Brian R. , Pe’eri Shachak , Rzhanov Yuri
Published: April 2013

This study presents and compares two new methods of assessing the uncertainty of lidar-derived National Shoreline mapped by NOAA’s National Geodetic Survey: an empirical (ground-based) approach and a stochastic (Monte Carlo) approach.
A quasi gradient-index antireflection coating for solar cell
Authors: Hu C. A. , Yang T. J. , Yang S. L.
Published: April 2013

A five-layer quasi-parabolic antireflection coat is proposed to improve the conversion efficiency of solar cells. The performance is perfect over a wide wavelength and wide incident angle.
Improved contact design methodology for solar cells
Authors: Li Jing-Jing , Ding Ding , Lim Swee Hoe , Zhang Yong-Hang
Published: April 2013

The optimization of the layout of front metal contact is critical for improving the efficiency of solar cells under high concentrations. In the traditional design approach, the optimum finger spacing and busbar width are determined by minimizing the total power loss associated with the front contact[1－3]. However, there are several assumptions that need to be carefully reexamined. In this work, a rigorous approach to optimize the layout of the front contact is proposed.
Optical absorption enhancement in thin-film organic photovoltaic solar cells through the excitation of plasmonic modes in metallic gratings
Authors: Min Changjun , Li Jennifer , Veronis Georgios , Lee Jung-Yong , Fan Shanhui , Peumans Peter
Published: April 2013

We theoretically demonstrate up to ~50% enhancement of the overall optical absorption in thin-film organic photovoltaic solar cells in which the top transparent electrode is partially substituted by a periodic metallic grating.
Advanced Aspects of Indoor Characterization of CPV Modules
Authors: Domínguez César , Askins Stephen , Antón Ignacio , Sala Gabriel
Published: April 2013

A comprehensive characterization process for concentrator PV modules is presented, based on a commercial solar simulator. Advanced aspects about irradiance and spectrum conditions monitoring are introduced. Recommendations of the forthcoming IEC norm are addressed.
Photovoltaic Cell Texture Quantitatively Relates to Efficiency
Authors: Blewett Nelson , Novak Erik
Published: April 2013

This paper describes a set of experiments which quantify the relationship between surface texture and photovoltaic cell efficiency using three-dimensional surface parameters calculated from white-light interferometric measurements.
Study of the Electrocatalytic Activity of Cerium Oxide and Gold-Studded Cerium Oxide Nanoparticles Using a Sonogel-Carbon Material as Supporting Electrode: Electroanalytical Study in Apple Juice for Babies
Authors: Abdelrahim M. , Benjamin Stephen , Cubillana-Aguilera Laura , Naranjo-Rodríguez Ignacio , De Cisneros José , Delgado Juan , Palacios-Santander José
Published: April 2013

The present work reports a study of the electrocatalytic activity of CeO2 nanoparticles and gold sononanoparticles (AuSNPs)/CeO2 nanocomposite, deposited on the surface of a Sonogel-Carbon (SNGC) matrix used as supporting electrode and the application of the sensing devices built with them to the determination of ascorbic acid (AA) used as a benchmark analyte. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to investigate the electrocatalytic behavior of CeO2- and AuSNPs/CeO2-modified SNGC electrodes, utilizing different concentrations of CeO2 nanoparticles and different AuSNPs:CeO2 w/w ratios. The best detection and quantification limits, obtained for CeO2 (10.0 mg·mL−1)- and AuSNPs/CeO2 (3.25% w/w)-modified SNGC electrodes, were 1.59 × 10−6 and 5.32 × 10−6 M, and 2.93 × 10−6 and 9.77 × 10−6 M, respectively, with reproducibility values of 5.78% and 6.24%, respectively, for a linear concentration range from 1.5 µM to 4.0 mM of AA. The electrochemical devices were tested for the determination of AA in commercial apple juice for babies. The results were compared with those obtained by applying high performance liquid chromatography (HPLC) as a reference method. Recovery errors below 5% were obtained in most cases, with standard deviations lower than 3% for all the modified SNGC electrodes. Bare, CeO2- and AuSNPs/CeO2-modified SNGC electrodes were structurally characterized using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). AuSNPs and AuSNPs/CeO2 nanocomposite were characterized by UV–vis spectroscopy and X-ray diffraction (XRD), and information about their size distribution and shape was obtained by transmission electron microscopy (TEM). The advantages of employing CeO2 nanoparticles and AuSNPs/CeO2 nanocomposite in SNGC supporting material are also described. This research suggests that the modified electrode can be a very promising voltammetric sensor for the determination of electroactive species of interest in real samples.
Simultaneous occurrence of polar stratospheric clouds and upper-tropospheric clouds caused by blocking anticyclones in the Southern Hemisphere
Authors: Kohma M. , Sato K.
Published: April 2013

Abstract. Previous studies have reported that polar stratospheric clouds (PSCs) are frequently observed simultaneously with upper-tropospheric clouds (UCs) in the Southern Hemisphere. However, it has not yet been examined whether the UCs that simultaneously occur with PSCs are actually located below the height of the tropopause, which is modified by tropospheric disturbances. Furthermore, the mechanism of this simultaneous occurrence has not yet been clarified. This study statistically examines the simultaneous appearance of PSCs and UCs using the Cloud-Aerosol Lidar and Pathfinder Satellite Observation (CALIPSO) for the five austral winters of 2007–2011. From correlation analyses and statistical dependence tests, it is shown that the simultaneous occurrence frequencies of clouds with an altitude range of 15–25 km and 9–11 km are significant. The analyses based on tropopause-relative altitude suggest that the occurrence frequency of clouds at altitudes higher than 6 km above the local tropopause (i.e., PSCs) is significantly correlated with that of clouds around and slightly above the tropopause. These results indicate that the UCs observed simultaneously with PSCs reported in previous case studies are likely located around and slightly above the tropopause rather than in the troposphere. It is also shown that the simultaneous occurrence of PSCs and UCs is frequently associated with blocking highs that have large horizontal scales (several thousand kilometers) and tall structure (up to a height of ~15 km). The longitudinal variation of blocking high frequency accords well with that of the simultaneous occurrence frequency of PSCs and UCs. This fact suggests that the blocking highs provide a preferable condition for such simultaneous occurrences. Moreover, the composition of PSCs is investigated as a function of relative longitude of the anticyclones including blocking highs. It was discovered that relatively high proportions of STS (super-cooled ternary solutions), Ice, and Mix2 (mixture of nitric acid trihydrate and STS) types are distributed towards the windward, near, and leeward side of anticyclones in westerly background flows, respectively.
Expenditure-Based Segmentation: Application of Quantile Regression to Analyse the Travel Expenditures of Baby Boomer Households
Authors: Kuo Hsiao-I , Lu Ching-Lung
Published: April 2013

The substantial size of the senior worldwide population and its demands have drawn considerable attention, making it the ‘silver economy’ or ‘senior’ market. Baby boomers, those born in the years after the Second World War, or more typically between 1946 and 1964, are the specific focus of this research interest. This paper estimates the determinants of travel expenditures in baby boomer senior households in Taiwan. The traditional ordinary least squares (OLS) approach, combined with quantile regression analysis, is adopted to capture both the mean and quantile behaviours of travel expenditures in baby boomer households, using the 2008 Survey of Family Income and Expenditure (SFIE) in Taiwan. The OLS model is used to obtain the average (mean) expenditure behaviour, whereas quantile regression analysis captures the extreme behaviours of the two tails of travel expenditures in baby boomer households. The estimation outcomes have important policy implications for travel marketers and operators in the tourism industry who seek to understand baby boomer senior consumers.
On the Regional Economic Effects of the Pope's Journeys: Evidence from the Visit to Santiago de Compostela in 2010
Authors: Barajas Angel , Lago-Peñas Santiago , Sanchez Patricio
Published: April 2013

This study estimates the economic impact of the Pope's visit on 6 November 2010 on the region of Galicia. Several sources of information are used, including the authors' own surveys, interviews, official statistical sources, press and audiometric studies developed by specialized companies. The cost–benefit analysis methodological approach is applied. Overall, the authors conclude that the net effects are clearly positive in terms of boosting regional economic activity and tourism promotion. Conversely, tax returns for the regional government are very low due to the fiscal federal arrangements in Spain.
Considerations of Microstructural Influences for Diffusion Welding of Metals in Microsystem Technology
Authors: Gietzelt Thomas , Toth Volker , Lambach Heinz , Dittmeyer Roland
Published: April 2013

Diffusion welding is a special high‐tech solid joining technique. Most research was done and publications were written in the years between 1970 and 1980. The aim of this paper is to take a closer look at the fundamental processes inside the material during diffusion welding and to discuss the relation between the materials microstructure for diffusion processes from a material science point of view. For this, it is necessary to discuss the impact of different lattice defects and to observe the intrinsic energetically conditions of a metal originating from its delivery state and manufacturing history, as well as its surface condition. In particular, emphasis is paid to the special requirements for joining of micro process devices.
How epigenetic mutations can affect genetic evolution: Model and mechanism
Authors: Klironomos Filippos D. , Berg Johannes , Collins Sinéad
Published: April 2013

We hypothesize that heritable epigenetic changes can affect rates of fitness increase as well as patterns of genotypic and phenotypic change during adaptation. In particular, we suggest that when natural selection acts on pure epigenetic variation in addition to genetic variation, populations adapt faster, and adaptive phenotypes can arise before any genetic changes. This may make it difficult to reconcile the timing of adaptive events detected using conventional population genetics tools based on DNA sequence data with environmental drivers of adaptation, such as changes in climate. Epigenetic modifications are frequently associated with somatic cell differentiation, but recently epigenetic changes have been found that can be transmitted over many generations. Here, we show how the interplay of these heritable epigenetic changes with genetic changes can affect adaptive evolution, and how epigenetic changes affect the signature of selection in the genetic record.
Reduced Diurnal Variation of Heart Rate is Associated With Increased Plasma B‐Type Natriuretic Peptide Level in Patients With Atrial Fibrillation
Authors: Kamikawa Shigeshi , Miyoshi Toru , Doi Masayuki , Orita Naoko , Sangawa Mutsuko , Nakatsu Takaaki , Noguchi Youko , Hirohata Satoshi , Kusachi Shozo , Nakamura Kazufumi , Ito Hiroshi
Published: April 2013

Background

The plasma B‐type natriuretic peptide (BNP) level has been shown to be increased in patients with chronic atrial fibrillation (AF) independent of left ventricular ejection fraction (LVEF). The purpose of this study is to evaluate the relationship between the plasma BNP level and heart rate variation in patients with AF.

Hypothesis

The plasma BNP level is associated with heart rate variation in patients with AF.

Methods

A total of 102 patients with AF and preserved LVEF were included from 2 hospitals. The ambulatory electrocardiographic recording and measurement of plasma BNP levels were performed simultaneously. Echo‐Doppler parameters were measured as the average of 10 consecutive cardiac cycles.

Results

A difference in the mean heart rate between night and day (DIFF) and the standard deviation of the 5‐miniute mean R‐R interval (SDARR) were significantly associated with log‐transformed BNP levels (r = −0.411, P < 0.001 and r = −0.243, P = 0.049, respectively). In echocardiography, the ratio of E velocity to early diastolic velocity, which reflects left ventricular (LV) filling pressure, was significantly correlated with the DIFF and SDARR, along with the log‐transformed BNP level. Stepwise multiple linear regression analysis revealed that the DIFF and age were independent factors related with the BNP level (P < 0.01).

Conclusions

The reduced diurnal variation of heart rate was significantly associated with increased BNP, which is linked to LV diastolic dysfunction in patients with AF.
Beitragsserie: Eurocode 6 für Deutschland – Beispiele zur Bemessung von Mauerwerk
Authors: Steinigen Frank
Published: April 2013

Anm. der Redaktion: Mit dieser Beitragsserie sollen unseren Lesern fortlaufend Beispiele für die Berechnung und Bemessung von Bauteilen aus Mauerwerk nach Eurocode 6 (DIN EN 1996‐1‐1 und ‐3 mit dem jeweiligen deutschen Nationalen Anhang) zur Verfügung gestellt werden, um dem Anwender die Einarbeitung in die neue Norm, die nunmehr seit 01. 07. 2012 in Deutschland angewendet werden darf, zu erleichtern.

Editorial staff: This series presents working examples for the design of masonry members according to Eurocode 6 (DIN EN 1996‐1‐1 and ‐3 together with the German national Annex) in the future. It should facilitate our readers the adjustment to the new code which can be applied since July 1 2012 in Germany.

Nachfolgend wird die Nachweisführung einer Außenwand in einem Mehrfamilienhaus nach Eurocode 6 mit NA vorgestellt. Es handelt sich dabei um einen Anwendungsfall mit kombinierter Beanspruchung aus Deckenverdrehung und Gebäudestabilisierung, bei dem der Nachweis der Doppelbiegung zu führen ist.

Design of an external wall with the standard method of EC 6. The verification of an external wall of an apartment house in accordance with Eurocode 6 and NA is presented subsequently. It’s a question of an application of combined stressing because of slab rotation and stabilisation of the building, where the biaxial bending has to be proofed.
Chemical in‐gel deglycosylation of O‐glycoproteins improves their staining and mass spectrometric identification
Authors: Bellwied Petra , Staubach Simon , Hanisch Franz‐Georg
Published: April 2013

Heavily O‐glycosylated membrane‐tethered or secreted proteins often escape identification by gel‐based proteomics due to weak staining and low identification rates in MS/MS. The present protocol refers to a chemical in‐gel de‐O‐glycosylation of proteins based on repeated oxidation/elimination of glycans leaving the protein backbone intact at the gel position of the native glycoprotein. On restaining prior to spot picking, the deglycosylated proteins are detectable at increased staining intensities when applying fluorescent dyes or silver stains. Evidence shows that de‐O‐glycosylation of proteins in gels is efficient and does not introduce structural artifacts into the protein backbones. In‐gel trypsin digestion of deglycosylated proteins, such as human glycophorin A, revealed strongly enhanced sequence coverage in LC‐ESI MS/MS. The protocol is applicable in 1D and 2D gel settings within one working day.
Atmospheric deposition fluxes of 26 elements over the Southern Indian Ocean: Time series on Kerguelen and Crozet Islands
Authors: Heimburger Alexie , Losno Rémi , Triquet Sylvain , Nguyen Elisabeth Bon
Published: April 2013

Atmospheric deposition of dust is suspected to have a significant impact on biogeochemical processes in high‐nutrient‐low‐chlorophyll waters of the open ocean. In this study, we report time series of atmospheric deposition samples collected over two years at three different sites on Kerguelen and Crozet Islands in the Southern Indian Ocean. Total atmospheric deposition fluxes were measured for a large suite of elements (Al, As, Ba, Ca, Ce, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Na, Nd, Ni, Pb, Rb, S, Si, Sr, Ti, U, V, and Zn). Most of them are identified as coming from sea‐salt or crustal sources, but enrichment factor variabilities of Pb, As, Cr, Cu, and V highlight an anthropogenic contribution during the austral winter for these five elements. For Al, Fe, Mn, and Si, deposition fluxes are similar for both Kerguelen and Crozet Islands. Fluxes for the other non‐sea‐salt elements exhibit differences below a factor of five with a decreasing gradient from Crozet to Kerguelen.
Potential of fluorescence spectroscopy for the characterisation of maple syrup flavours
Authors: Panneton Bernard , Clément Alain , Lagacé Luc
Published: April 2013

BACKGROUND

Maple syrup has high maket value. It is produced in North East America from the heat‐evaporated sap of Acer saccharum Marshall. For marketing purposes, there is interest in defining its flavour profile in a consistent and repeatable manner. An experiment was undertaken to explore the potential of autofluorescence of maple syrup induced at 275 and 360 nm to characterise flavours.

Results

A mixed data factor analysis revealed two independent groups of variables. One represents early season woody and late season empyreumatic flavours. The other is related to off‐flavour, confectionery and maple flavours. Maple and confectionery flavours are subtle, difficult to distinguish and opposed to off‐flavour. There were clear relationships among the two groups and fluorescence profiles. For each of the five basic flavours, discriminant models based on partial least squares regressions were developed. For each sample of syrup, flavours combined to form flavour profiles, and the results from the five discriminant models were aggregated to reproduce these profiles. For excitation at 275 nm, the woody/off‐flavour and confectionery/empyreumatic/maple flavour profiles were classified correctly 86 and 78% of the time (cross‐validation) respectively.

Conclusion

Induced autofluorescence spectra were shown to contain information related to maple syrup flavours. This fluorescence–flavour relationship is not considered quantitative yet, and further research avenues are proposed. © 2013 Society of Chemical Industry
Effect of sweeteners and hydrocolloids on quality attributes of reduced‐calorie carrot juice
Authors: Sinchaipanit Pornrat , Kerr William L , Chamchan Rungrat
Published: April 2013

BACKGROUND

Different ratios of combined sweeteners were modified to produce an acceptable reduced‐calorie carrot juice. Various hydrocolloids were investigated to improve juice cloud stability. Changes in juice quality attributes were analysed.

RESULTS

A combination of the sweeteners aspartame (ASP), acesulfame potassium (ACE) and sucralose (SUC) was partially used to replace the sugar in carrot juice. Sensory studies indicated that juice containing 50 g kg−1 sucrose and 160 mg kg−1 ASP/ACE/SUC (6:1.5:1) had the highest acceptability. Thermal processing at 80 °C for 1 min retained acceptable β‐carotene (4300 µg kg−1) and did not result in the cooked flavour noted at 65 °C/30 min. Pectin (PE), carboxymethyl cellulose (CMC), guar gum (GU) and gellan gum (GE) were used to stabilise the juice cloud during storage. The addition of 0.1–0.3 g kg−1 GE or 2.0 g kg−1 GU to reduced‐calorie carrot juice greatly improved cloud stability after storage at 4 °C for 30 days.

CONCLUSION

The formulation of reduced‐calorie carrot juice with ASP/ACE/SUC (6:1.5:1) provided synergistic sweetness and highly acceptable sensory properties. The addition of 0.3 g kg−1 GE greatly enhanced juice cloud stability during storage. © 2013 Society of Chemical Industry
Evaluation of the processing of Perna perna mussels: the influence of water quality involved in the cooling operations in the physico‐chemical and microbiological characteristics of the product
Authors: de Lima Marieli , Melo Maria Carolina Lampert , Monteiro Alcilene Rodrigues
Published: April 2013

BACKGROUND

The state of Santa Catarina in Brazil is a large producer of Perna perna mussels. However, raw and processed mussels have a short shelf life because of their high microbiological count, such as Vibrio spp. This study evaluated the microbiological and physicochemical quality of raw and ready‐to‐eat mussels and the quality of water and ice used in the processing of mussels.

RESULTS

The microbiological conditions of water and ice used in the processing are not in accordance with Brazilian legislation because of the presence of coliforms and Vibrio spp. For ready‐to‐eat mussels, counts of psychrophilic and psychrotrophic micro‐organisms reached 105 colony‐forming units g−1, a value close to the onset of product degradation during storage. Counts of coliforms, coagulase‐positive Staphylococcus, Salmonella spp. and sulfite‐reducing Clostridium in the mussels analysed during processing are in accordance with Brazilian law. The F value for the sterilisation procedure was lower than that required for Clostridium botulinum.

CONCLUSION

The study shows that microbiological cross‐contamination occurred during the processing of mussels. Rigorous control is necessary from the production area of mussels to retailers. Good manufacturing practices must be implemented in the industry and cross‐contamination avoided, mainly by Vibrio spp. after heat treatment.© 2013 Society of Chemical Industry
Tensorial elastic network model for protein dynamics: Integration of the anisotropic network model with bond‐bending and twist elasticities
Authors: Srivastava Amit , Halevi Roee Ben , Veksler Alexander , Granek Rony
Published: April 2013

We present a tensorial elastic network model (TNM) to describe the equilibrium fluctuations of proteins near their native fold structure. The model combines the anisotropic network model (ANM), bond bending elasticity, and backbone twist elasticity, and can predict both the isotropic fluctuations, similar to the Gaussian network model (GNM), and anisotropic fluctuations, similar to the ANM. TNM performs equally well for B‐factor predictions as GNM and predicts the anisotropy of B‐factors better than ANM. The model also outperforms the ANM in its predictability of the complete anisotropic displacement parameters. Proteins 2012; © 2012 Wiley Periodicals, Inc.
Capturing the energetics of water insertion in biological systems: The water flooding approach
Authors: Chakrabarty Suman , Warshel Arieh
Published: April 2013

Consistent description of the effect of internal water in proteins has been a major challenge for both simulation and experimental studies. Describing this effect has been particularly important and elusive in cases of charges in protein interiors. Here, we present a new microscopic method that provides an efficient way for simulating the energetics of water insertion. Instead of performing explicit Monte Carlo (MC) moves on the insertion process, which generally involves an enormous number of rejected attempts, our method is based on generating trial configurations with excess amount of internal water, estimating the relevant free energy by the linear response approximation, and then using a postprocessing MC treatment to filter out a limited number of configurations from a large possible set. Our approach is validated on particularly challenging test cases including the pKa of the V66D mutation in Staphylococcal nuclease, Glu286 in cytochrome c oxidase (CcO) and the energetics of a protonated water molecule in the D channel of CcO. The new postprocessing method allows us to reproduce the relevant energetics of highly unstable charges in protein interiors using fully microscopic calculations and provides a substantial improvement over regular microscopic free energy estimates. This advance established the effectiveness of our water insertion strategy in challenging cases that have not been addressed successfully by other microscopic methods. Furthermore, our study provides a new exciting view on the crucial effect of water penetration in key biological systems as well as a new view on the nature of the dielectric in protein interiors. Proteins 2013. © 2012 Wiley Periodicals, Inc.
Crystal structure of NirD, the small subunit of the nitrite reductase NirbD from Mycobacterium tuberculosis at 2.0 Å resolution
Authors: Izumi Atsushi , Schnell Robert , Schneider Gunter
Published: April 2013

NirD is part of the nitrite reductase complex NirBD that catalyses the reduction of nitrite to NH3 in nitrate assimilation and anaerobic respiration. The crystal structure analysis of NirD from Mycobacterium tuberculosis shows a double β‐sandwich fold. NirD is related in three‐dimensional structure and sequence to the Rieske proteins; however, it does not contain any Fe–S cluster or other cofactors that might be involved in electron transfer. A cysteine residue at the protein surface, conserved in NirD homologues lacking the iron–sulfur cluster might be important for the interaction with NirB and possibly stabilize one of the Fe–S centers in this subunit. Proteins 2012. © 2012 Wiley Periodicals, Inc.
The asphericity of random 2‐dimensional complexes
Authors: Costa A.E. , Farber M.
Published: April 2013

We study random 2‐dimensional complexes in the Linial–Meshulam model and prove that for the probability parameter satisfying

urn:x-wiley:10429832:media:rsa20499:rsa20499-math-0002

a random 2‐complex Y contains several pairwise disjoint tetrahedra such that the 2‐complex Z obtained by removing any face from each of these tetrahedra is aspherical. Moreover, we prove that the obtained complex Z satisfies the Whitehead conjecture, i.e. any subcomplex is aspherical. This implies that Y is homotopy equivalent to a wedge where Z is a 2‐dimensional aspherical simplicial complex. We also show that under the assumptions

urn:x-wiley:10429832:media:rsa20499:rsa20499-math-0005

where c > 3 and , the complex Z is genuinely 2‐dimensional and in particular, it has sizable 2‐dimensional homology; it follows that in the indicated range of the probability parameter p the cohomological dimension of the fundamental group of a random 2‐complex equals 2. © 2013 Wiley Periodicals, Inc. Random Struct. Alg., 46, 261–273, 2015
Interaction of treatment with a continuous variable: simulation study of significance level for several methods of analysis
Authors: Royston Patrick , Sauerbrei Willi
Published: April 2013

Interactions between treatments and covariates in RCTs are a key topic. Standard methods for modelling treatment–covariate interactions with continuous covariates are categorisation or linear functions. Both approaches are easily criticised, but for different reasons. Multivariable fractional polynomial interactions, an approach based on fractional polynomials with the linear interaction model as the simplest special case, was proposed. Four variants of multivariable fractional polynomial interaction (FLEX1–FLEX4), allowing varying flexibility in functional form, were suggested. However, their properties are unknown, and comparisons with other procedures are unavailable. Additionally, we consider various methods based on categorisation and on cubic regression splines. We present the results of a simulation study to determine the significance level (probability of a type 1 error) of various tests for interaction between a binary covariate (‘treatment effect’) and a continuous covariate in univariate analysis. We consider a simplified setting in which the response variable is conditionally normally distributed, given the continuous covariate. We consider two main cases with the covariate distribution well behaved (approximately symmetric) or badly behaved (positively skewed). We construct nine scenarios with different functional forms for the main effect. In the well‐behaved case, significance levels are in general acceptably close to nominal and are slightly better for the larger sample size (n = 250 and 500 were investigated). In the badly behaved case, departures from nominal are more pronounced for several approaches. For a final assessment of these results and recommendations for practice, a study of power is needed. Copyright © 2013 John Wiley & Sons, Ltd.
Thermalization of the spectral function in strongly coupled two dimensional conformal field theories
Authors: Balasubramanian V. , Bernamonti A. , Craps B. , Keränen V. , Keski-Vakkuri E. , Müller B. , Thorlacius L. , Vanhoof J.
Published: April 2013

Abstract

Using Wigner transforms of Green functions, we discuss non-equilibrium generalizations of spectral functions and occupation numbers. We develop methods for computing time-dependent spectral functions in conformal field theories holographically dual to thin-shell AdS-Vaidya spacetimes.
Shackleton's emperor penguins
Authors: Stonehouse Bernard
Published: April 2013

The loss of the expedition ship SYEndurance, and the subsequent dispersal of staff and crew, resulted in very little scientific information emerging from the Imperial Trans-Antarctic Expedition 1914–1917. Among surviving records were the charts and diaries maintained by the ship's master, F.A. Worsley. During the voyage in January 1915 along the ice cliffs of the Weddell Sea coast, Worsley recorded the ship's daily progress, soundings and trawling and dredging activities, and also daily encounters with seals, whales and seabirds, On 12 January he noted a group of fledgling emperor penguin chicks (Aptenodytes forsteri) on an ice foot, clearly a remnant of what was then only the third-known breeding colony of the species. Shackleton's first published account of the expedition mentioned the chicks only in a brief note (one that was omitted from later editions), and no further report covering Worsley's observations appeared in scientific literature. In consequence the discovery of the breeding colony and records of emperor penguin distribution along the Weddell Sea coast have since been overlooked by avian biologists, regrettably including the present author. This paper discusses the identity of the colony, Worsley's observations that foreshadowed the later discovery of more breeding concentrations along the coast, and a possible reason why colonies occur at points of particular glaciological disturbance.
Ordering in the motet fascicles of the Florence manuscript
Authors: BRADLEY CATHERINE A.
Published: April 2013

Florence, Biblioteca Medicea Laurenziana, Plut.29.1 (F) is considered the earliest extant manuscript to preserve a collection of motets, with two fascicles devoted to this new genre. Scholars have long emphasised the strict liturgical sequence of the first motet fascicle, in contrast to the seeming lack of order in the second. This article engages with questions of liturgical arrangement in F, exploring the possibility of a liturgical function for motets in this source. It undertakes a re-examination of the ordering of motets in F, proposing two new organisational principles applicable across both fascicles: first, that the arrangement of motets may have been influenced by an awareness of related clausulae and discant materials extant elsewhere in F; and second, that ordering of the collection reflects the relative dissemination or ‘popularity’ of motets and their related materials.
XNA marks the spot
Authors: Hunter Philip
Published: April 2013

Synthetic genomics tinkers with nucleic acids to understand the evolution of these molecules of life. But the so‐called ‘XNAs’ created also hold great potential for diagnostic and therapeutic applications.
Investigations on electrical and magnetic properties of multiferroic [(1−x)Pb(Fe0.5Nb0.5)O3−xNi0.65Zn0.35Fe2O4] composites
Authors: Pradhan Dhiren K. , Barik Sujit K. , Sahoo Satyaprakash , Puli Venkata S. , Katiyar R. S.
Published: April 2013

Here, we report the magnetic, ferroelectric, dielectric properties, and Raman spectroscopic studies of multiferroic [(1−x)Pb(Fe0.5Nb0.5)O3−xNi0.65Zn0.35Fe2O4] composites at room temperature. The phase formation of composites was confirmed independently from the X-ray diffraction and Raman studies. The room temperature magnetic studies reveal ferromagnetic like behavior of these composites in contrast to the paramagnetic nature of Pb(Fe0.5Nb0.5)O3. Furthermore, with increasing x, the saturation magnetization, remnant magnetization, and coercive fields are found to increase. The electrical characterizations of these composites reveal a decrease in remnant polarization and dielectric constant with increasing x. More importantly, the x = 0.2 composite is found to be a very good multiferroic material at room temperature among the composites and could be a potential candidate for future potential applications.
Conformers of β-aminoisobutyric acid probed by jet-cooled microwave and matrix isolation infrared spectroscopic techniques
Authors: Kuş N. , Sharma A. , Peña I. , Bermúdez M. C. , Cabezas C. , Alonso J. L. , Fausto R.
Published: April 2013

β-aminoisobutyric acid (BAIBA) has been studied in isolation conditions: in the gas phase and trapped into a cryogenic N2 matrix. A solid sample of the compound was vaporized by laser ablation and investigated through their rotational spectra in a supersonic expansion using two different spectroscopic techniques: broadband chirped pulse Fourier transform microwave spectroscopy and conventional molecular beam Fourier transform microwave spectroscopy. Four conformers with structures of two types could be successfully identified by comparison of the experimental rotational and 14N nuclear quadruple coupling constants with those predicted theoretically: type A, bearing an OH⋯N intramolecular hydrogen bond and its carboxylic group in the trans geometry (H–O–C=O dihedral ∼180°), and type B, having an NH⋯O bond and the cis arrangement of the carboxylic group. These two types of conformers could also be trapped from the gas phase into a cryogenic N2 matrix and probed by Fourier transform infrared (IR) spectroscopy. In situ irradiation of BAIBA isolated in N2 matrix of type B conformers using near-IR radiation tuned at the frequency of the O–H stretching 1st overtone (∼6930 cm−1) of these forms allowed to selectively convert them into type A conformers and into a new type of conformers of higher energy (type D) bearing an NH⋯O=C bond and a O–H “free” trans carboxylic group.
Ultrafast inter-ionic charge transfer of transition-metal complexes mapped by femtosecond X-ray powder diffraction
Authors: Freyer Benjamin , Zamponi Flavio , Juvé Vincent , Stingl Johannes , Woerner Michael , Elsaesser Thomas , Chergui Majed
Published: April 2013

The transient electronic and molecular structure arising from photoinduced charge transfer in transition metal complexes is studied by X-ray powder diffraction with a 100 fs temporal and atomic spatial resolution. Crystals containing a dense array of Fe(II)-tris(bipyridine) ([Fe(bpy)3]2 +) complexes and their \documentclass[12pt]{minimal}\begin{document}${\rm PF}_6^{\ -}$\end{document} PF 6− counterions display pronounced changes of electron density that occur within the first 100 fs after two-photon excitation of a small fraction of the [Fe(bpy)3]2 + complexes. Transient electron density maps derived from the diffraction data reveal a transfer of electronic charge from the Fe atoms and—so far unknown—from the \documentclass[12pt]{minimal}\begin{document}${\rm PF}_6^{\ -}$\end{document} PF 6− counterions to the bipyridine units. Such charge transfer (CT) is connected with changes of the inter-ionic and the Fe-bipyridine distances. An analysis of the electron density maps demonstrates the many-body character of charge transfer which affects approximately 30 complexes around a directly photoexcited one. The many-body behavior is governed by the long-range Coulomb forces in the ionic crystals and described by the concept of electronic polarons.
Electroresistance and current-induced metastable states in the thin film of half-doped manganite Pr0.5Sr0.5MnO3
Authors: Wang J. F. , Chen L. P. , Jiang Y. C. , Gao J.
Published: April 2013

Electroresistance (ER) effects and current-induced metastable states in the thin film of Pr0.5Sr0.5MnO3 were investigated. The initial state was insensitive to weak currents and susceptible to high-density currents. As the current density reached a certain value, metastable states, which were very sensitive to weak currents at low temperatures, were excited. It was found that as the excited current increased, the induced metastable state showed a larger electroresistance in a wider temperature range. Interfacial effects related to electrodes could be ruled out. The observed effects might be related to the coexistence and instability of the multiphases in manganites.
Effect of nitrogen doping on the electromagnetic properties of carbon nanotube-based composites
Authors: Kanygin M. A. , Sedelnikova O. V. , Asanov I. P. , Bulusheva L. G. , Okotrub A. V. , Kuzhir P. P. , Plyushch A. O. , Maksimenko S. A. , Lapko K. N. , Sokol A. A. , Ivashkevich O. A. , Lambin Ph.
Published: April 2013

Nitrogen-doped and pure carbon nanotube (CNT) based composites were fabricated for investigating their dielectric properties in static regime as well as electromagnetic response properties in microwave frequency range (Ka-band). Two classes of host matrix—polystyrene and phosphate unfired ceramics—have been used for composites fabrication. The study reveals miscellaneous effect of nitrogen doping on the dielectric permittivity, dc conductivity and electromagnetic interference shielding efficiency of CNT-based composites, produced with both polymer and ceramic matrices. The high-frequency polarizability, estimated for different-length CNTs, and static polarizability, calculated for nitrogen-containing CNT models using a quantum-chemical approach, show that this effect results from a decrease of the nanotube defect-free-length and deterioration of the polarizability with incorporation of nitrogen in pyridinic form.
Systematic study of near-infrared intersubband absorption of polar and semipolar GaN/AlN quantum wells
Authors: Machhadani H. , Beeler M. , Sakr S. , Warde E. , Kotsar Y. , Tchernycheva M. , Chauvat M. P. , Ruterana P. , Nataf G. , De Mierry Ph. , Monroy E. , Julien F. H.
Published: April 2013

We report on the observation of intersubband absorption in GaN/AlN quantum well superlattices grown on (112¯2)-oriented GaN. The absorption is tuned in the 1.5–4.5 μm wavelength range by adjusting the well thickness. The semipolar samples are compared with polar samples with identical well thickness grown during the same run. The intersubband absorption of semipolar samples shows a significant red shift with respect to the polar ones due to the reduction of the internal electric field in the quantum wells. The experimental results are compared with simulations and confirm the reduction of the polarization discontinuity along the growth axis in the semipolar case. The absorption spectral shape depends on the sample growth direction: for polar quantum wells the intersubband spectrum is a sum of Lorentzian resonances, whereas a Gaussian shape is observed in the semipolar case. This dissimilarity is explained by different carrier localization in these two cases.