bluuebunny/crossref_metadata_2025 huggingface dataset:
Band gap bowing and optical polarization switching in AlGaN alloys
Authors: Coughlan Conor , Schulz Stefan , Caro Miguel A. , O'Reilly Eoin P.
Published: January 2015

We present a detailed theoretical study of the band gap bowing of wurtzite AlGaN alloys over the full composition range. Our theoretical framework is based on an atomistic tight‐binding model, including local strain and built‐in potential variations due to random alloy fluctuations. We extract a bowing parameter for the band gap of  eV, which is in good agreement with experimental data. Our analysis shows that the bowing of the band gap mainly arises from bowing of the conduction band edge; for the composition dependence of the valence band edge energy we find a close to linear behavior. Finally, we investigate the wave function character of the valence band edge as a function of GaN content x. Our analysis reveals an optical polarization switching around , which is in the range of reported experimental data.
The Use of Nanoparticles to Deliver Nitric Oxide to Hepatic Stellate Cells for Treating Liver Fibrosis and Portal Hypertension
Authors: Duong Hien T. T. , Dong Zhixia , Su Lin , Boyer Cyrille , George Jacob , Davis Thomas P. , Wang Jianhua
Published: January 2015

Polymeric nanoparticles are designed to transport and deliver nitric oxide (NO) into hepatic stellate cells (HSCs) for the potential treatment of both liver fibrosis and portal hypertension. The nanoparticles, incorporating NO donor molecules (S‐nitrosoglutathione compound), are designed for liver delivery, minimizing systemic delivery of NO. The nanoparticles are decorated with vitamin A to specifically target HSCs. We demonstrate, using in vitro and in vivo experiments, that the targeted nanoparticles are taken up specifically by rat primary HSCs and the human HSC cell line accumulating in the liver. When nanoparticles, coated with vitamin A, release NO in liver cells, we find inhibition of collagen I and α‐smooth muscle actin (α‐SMA), fibrogenic genes associated with activated HSCs expression in primary rat liver and human activated HSCs without any obvious cytotoxic effects. Finally, NO‐releasing nanoparticles targeted with vitamin A not only attenuate endothelin‐1 (ET‐1) which elicites HSC contraction but also acutely alleviates haemodynamic disorders in bile duct‐ligated‐induced portal hypertension evidenced by decreasing portal pressure (≈20%) and unchanging mean arterial pressure. This study clearly shows, for the first time, the potential for HSC targeted nanoparticle delivery of NO as a treatment for liver diseases with proven efficacy for alleviating both liver fibrosis and portal hypertension.
SALOON: a platform for selecting and configuring cloud environments
Authors: Quinton Clément , Romero Daniel , Duchien Laurence
Published: January 2015

Migrating legacy systems or deploying a new application to a cloud environment has recently become very trendy, because the number of cloud providers available is still increasing. These cloud environments provide a wide range of resources at different levels of functionality, which must be appropriately configured by stakeholders for the application to run properly. Handling this variability during the configuration and deployment stages is known as a complex and error‐prone process, usually made in anad hocmanner. In this paper, we proposeSALOON, asoftware product lines‐based platform to face these issues. We describe the architecture of theSALOONplatform, which relies on feature models combined with a domain model used to select among cloud environments a well‐suited one.SALOONsupports stakeholders while configuring the selected cloud environment in a consistent way and automates the deployment of such configurations through the generation of executable configuration scripts. This paper also reports on some experiments, showing that usingSALOONsignificantly reduces time to configure a cloud environment compared with a manual approach and provides a reliable way to find a correct and suitable configuration. Moreover, our empirical evaluation shows that our approach is effective and scalable to properly deal with a significant number of cloud environments. Copyright © 2015 John Wiley & Sons, Ltd.
Climate change impacts and adaptation in forest management: a review
Authors: Keenan Rodney J.
Published: January 2015

Key message

Adaptation of forest management to climate change requires an understanding of the effects of climate on forests, industries and communities; prediction of how these effects might change over time; and incorporation of this knowledge into management decisions. This requires multiple forms of knowledge and new approaches to forest management decisions. Partnerships that integrate researchers from multiple disciplines with forest managers and local actors can build a shared understanding of future challenges and facilitate improved decision making in the face of climate change.

Context

Climate change presents significant potential risks to forests and challenges for forest managers. Adaptation to climate change involves monitoring and anticipating change and undertaking actions to avoid the negative consequences and to take advantage of potential benefits of those changes.

Aims

This paper aimed to review recent research on climate change impacts and management options for adaptation to climate change and to identify key themes for researchers and for forest managers.

Methods

The study is based on a review of literature on climate change impacts on forests and adaptation options for forest management identified in the Web of Science database, focusing on papers and reports published between 1945 and 2013.

Results

One thousand one hundred seventy-two papers were identified in the search, with the vast majority of papers published from 1986 to 2013. Seventy-six percent of papers involved assessment of climate change impacts or the sensitivity or vulnerability of forests to climate change and 11 % (130) considered adaptation. Important themes from the analysis included (i) predicting species and ecosystem responses to future climate, (ii) adaptation actions in forest management, (iii) new approaches and tools for decision making under uncertainty and stronger partnerships between researchers and practitioners and (iv) policy arrangements for adaptation in forest management.

Conclusions

Research to support adaptation to climate change is still heavily focused on assessing impacts and vulnerability. However, more refined impact assessments are not necessarily leading to better management decisions. Multi-disciplinary research approaches are emerging that integrate traditional forest ecosystem sciences with social, economic and behavioural sciences to improve decision making. Implementing adaptation options is best achieved by building a shared understanding of future challenges among different institutions, agencies, forest owners and stakeholders. Research-policy-practice partnerships that recognise local management needs and indigenous knowledge and integrate these with climate and ecosystem science can facilitate improved decision making.
Tis better to give than receive? How and when gender and residence‐based segments predict choice of donation‐ versus discount‐based promotions
Authors: Winterich Karen Page , Carter Robert E. , Barone Michael J. , Janakiraman Ramkumar , Bezawada Ram
Published: January 2015

Donation promotions that tie product purchase to charitable contributions are common in the marketplace. Yet little is known about the sensitivity of different consumer segments to such promotions, particularly relative to traditional discount‐based promotions. To address this void, the authors consider the extent to which consumers in traditional demographic segments based on gender and residence vary in their propensity to choose donation versus discount promotions. An experiment along with a field study using in‐market data show that female and rural consumers exhibit higher choice probabilities for donation promotions than male and urban consumer segments. The experimental results also demonstrate that interdependence, at least in part, underlies the effect of these demographic and geographic segmentation variables on promotion choice. In addition to providing new theoretical insights involving interdependence and promotion choice, these results offer pragmatic guidance for managers targeting donation versus discount promotions to various consumer segments.
Race, Paternalism, and Foreign Aid: Evidence from U.S. Public Opinion
Authors: BAKER ANDY
Published: January 2015

Virtually all previous studies of domestic economic redistribution find white Americans to be less enthusiastic about welfare for black recipients than for white recipients. When it comes to foreign aid and international redistribution across racial lines, I argue that prejudice manifests not in an uncharitable, resentful way but in a paternalistic way because intergroup contact is minimal and because of how the media portray black foreigners. Using two survey experiments, I show that white Americans are more favorable toward aid when cued to think of foreign poor of African descent than when cued to think of those of East European descent. This relationship is due not to the greater perceived need of black foreigners but to an underlying racial paternalism that sees them as lacking in human agency. The findings confirm accusations of aid skeptics and hold implications for understanding the roots of paternalistic practices in the foreign aid regime.
Reporting accuracy of population dietary sodium intake using duplicate 24 h dietary recalls and a salt questionnaire
Authors: De Keyzer Willem , Dofková Marcela , Lillegaard Inger Therese L. , De Maeyer Mieke , Andersen Lene Frost , Ruprich Jirí , Řehůřková Irena , Geelen Anouk , van 't Veer Pieter , De Henauw Stefaan , Crispim Sandra Patricia , de Boer Evelien , Ocké Marga , Slimani Nadia , Huybrechts Inge
Published: January 2015

High dietary Na intake is associated with multiple health risks, making accurate assessment of population dietary Na intake critical. In the present study, reporting accuracy of dietary Na intake was evaluated by 24 h urinary Na excretion using the EPIC-Soft 24 h dietary recall (24-HDR). Participants from a subsample of the European Food Consumption Validation study (n 365; countries: Belgium, Norway and Czech Republic), aged 45–65 years, completed two 24 h urine collections and two 24-HDR. Reporting accuracy was calculated as the ratio of reported Na intake to that estimated from the urinary biomarker. A questionnaire on salt use was completed in order to assess the discretionary use of table and cooking salt. The reporting accuracy of dietary Na intake was assessed using two scenarios: (1) a salt adjustment procedure using data from the salt questionnaire; (2) without salt adjustment. Overall, reporting accuracy improved when data from the salt questionnaire were included. The mean reporting accuracy was 0·67 (95 % CI 0·62, 0·72), 0·73 (95 % CI 0·68, 0·79) and 0·79 (95 % CI 0·74, 0·85) for Belgium, Norway and Czech Republic, respectively. Reporting accuracy decreased with increasing BMI among male subjects in all the three countries. For women from Belgium and Norway, reporting accuracy was highest among those classified as obese (BMI ≥ 30 kg/m2: 0·73, 95 % CI 0·67, 0·81 and 0·81, 95 % CI 0·77, 0·86, respectively). The findings from the present study showed considerable underestimation of dietary Na intake assessed using two 24-HDR. The questionnaire-based salt adjustment procedure improved reporting accuracy by 7–13 %. Further development of both the questionnaire and EPIC-Soft databases (e.g. inclusion of a facet to describe salt content) is necessary to estimate population dietary Na intakes accurately.
Musiktherapie in der Kardiologie
Authors: Mastnak Wolfgang
Published: January 2015

Musik und Musiktherapie zeigen deutlich positiven Einfluss auf kardiologische Prozesse, obwohl hinsichtlich der Wirkfaktoren in der Szene Uneinigkeit herrscht. Teils werden direkte physiologische Wirkungen angenommen, teils geht man bezüglich der Effizienz von einer Abhängigkeit vom persönlichen ästhetischen Geschmacks aus. Studien von verschiedenen Universitäten und Forschungsinstituten weltweit spiegeln die Komplexität der musiktherapeutischen Fokusbildungen in der Kardiologie wider und umfassen koronare Problematiken, Rhythmusstörungen oder Bluthochdruck. Die Ergebnisse stammen aus medizinischen und physiologischen Untersuchen ebenso wie aus empirischen und phänomenologischen Studien und inkludieren auch religiöse, mythische oder archaische Aspekte. Insgesamt führt sich Sichtung der Lage zur Erkenntnis, dass Musiktherapie in der Kardiologie interdisziplinär zu verstehen ist, physiologische, pathologische, psychologische und kulturelle Ansätze integrierend.
Military Service and Suicidal Thoughts and Behaviors in a National Sample of College Students
Authors: Pease James L. , Monteith Lindsey L. , Hostetter Trisha A. , Forster Jeri E. , Bahraini Nazanin H.
Published: January 2015

Background: As a result of the post-9/11 GI Bill, increasing numbers of veterans are enrolling in college. However, little is known regarding suicidal outcomes among this group. In prior research, college student veterans reported high rates of suicidal ideation and attempt. Nonetheless, no research has examined whether military service is associated with increased suicide risk among college students. Aims: Our primary aims were to examine whether a history of military service was related to past-year suicidal ideation, plan, and attempt among college students. On the basis of previous research with college students, we hypothesized that students with a history of military service (i.e., current or prior) would report a higher percentage of past-year suicidal ideation, plan, and attempt. Our secondary aims were to examine the associations between military service and major depression and nonsuicidal self-injury. Method: Our sample included 3,290 college students with and without a history of military service who participated in the Healthy Minds Study in 2011 and 2012. Results: Military service was not significantly associated with past-year suicidal ideation, plan, or attempt. Students without a history of military service were more likely to report nonsuicidal self-injury. There was no significant difference in screening positive for major depression. Conclusions: These findings conflict with previous research that identified student veterans as being at elevated risk.
Hospital-Treated Deliberate Self-Harm in the Western Area of Northern Ireland
Authors: Corcoran Paul , Griffin Eve , O’Carroll Amanda , Cassidy Linda , Bonner Brendan
Published: January 2015

Background: The Northern Ireland Registry of Deliberate Self-Harm was established as an outcome of the Northern Ireland Suicide Prevention Strategy and Action Plan – Protect Life, beginning in the Western Health and Social Care Trust area. Aims: The study aimed to establish the incidence of hospital-treated deliberate self-harm in the Western Area of Northern Ireland, and to explore the profile of such presentations. Method: Deliberate self-harm presentations made to the three hospital emergency departments operating in the area during the period 2007–2012 were recorded. Results: There were 8,175 deliberate self-harm presentations by 4,733 individuals. Respectively, the total, male, and female age-standardized incidence rate was 342, 320, and 366 per 100,000 population. City council residents had a far higher self-harm rate. The peak rate for women was among 15–19-year-olds (837 per 100,000) and for men was among 20–24-year-olds (809 per 100,000). Risk of repetition was higher in 35–44-year-old patients if self-cutting was involved, but was most strongly associated with the number of previous self-harm presentations. Conclusion: The incidence of hospital-treated self-harm in Northern Ireland is far higher than in the Republic of Ireland and more comparable to that in England.
Effect of carbonic anhydrase on silicate weathering and carbonate formation at present day CO2 concentrations compared to primordial values
Authors: Xiao Leilei , Lian Bin , Hao Jianchao , Liu Congqiang , Wang Shijie
Published: January 2015

It is widely recognized that carbonic anhydrase (CA) participates in silicate weathering and carbonate formation. Nevertheless, it is still not known if the magnitude of the effect produced by CA on surface rock evolution changes or not. In this work, CA gene expression from Bacillus mucilaginosus and the effects of recombination protein on wollastonite dissolution and carbonate formation under different conditions are explored. Real-time fluorescent quantitative PCR was used to explore the correlation between CA gene expression and sufficiency or deficiency in calcium and CO2 concentration. The results show that the expression of CA genes is negatively correlated with both CO2 concentration and ease of obtaining soluble calcium. A pure form of the protein of interest (CA) is obtained by cloning, heterologous expression and purification. The results from tests of the recombination protein on wollastonite dissolution and carbonate formation at different levels of CO2 concentration show that the magnitudes of the effects of CA and CO2 concentration are negatively correlated. These results suggest that the effects of microbial CA in relation to silicate weathering and carbonate formation may have increased importance at the modern atmospheric CO2 concentration compared to 3 billion years ago.
A localized temporary negative pressure assisted microfluidic device for detecting keratin 19 in A549 lung carcinoma cells with digital PCR
Authors: Tian Qingchang , Song Qi , Xu Yanan , Zhu Qiangyuan , Yu Bingwen , Jin Wei , Jin Qinhan , Mu Ying
Published: January 2015

Digital polymerase chain reaction (dPCR) has played a major role in biological research, especially by providing an accurate counting of single nucleic acid molecules.
Simultaneous determination of 32 antibiotics and 12 pesticides in sediment using ultrasonic-assisted extraction and high performance liquid chromatography-tandem mass spectrometry
Authors: Chen Meng , Yi Qitong , Hong Jiajun , Zhang Lemeng , Lin Kunde , Yuan Dongxing
Published: January 2015

A method was developed for the simultaneous determination of four classes of antibiotics and three classes of pesticides in sediment.
Reliable palladium nanoparticle syntheses in aqueous solution: the importance of understanding precursor chemistry and growth mechanism
Authors: Kettemann Frieder , Wuithschick Maria , Caputo Gianvito , Kraehnert Ralph , Pinna Nicola , Rademann Klaus , Polte Jörg
Published: January 2015

The consideration of precursor chemistry and growth mechanism enables the reliable synthesis of palladium nanoparticles even in the absence of stabilizing agents.
Growth of micro-ikebana on a floating substrate: a method to monitor local supersaturation levels
Authors: Fischer V. , Karthaus O.
Published: January 2015

The growth of biomimetic SrCO3–SiO2 micro-ikebana was conducted by an organic additive-free process to monitor the degree of local supersaturation at the surface of a floating substrate. The obtained crystallization pattern mirrors the level of local concentration which was the basis to derive a mathematical equation for the prediction of local nucleation rates.
Hybrid wood materials with improved fire retardance by bio-inspired mineralisation on the nano- and submicron level
Authors: Merk Vivian , Chanana Munish , Keplinger Tobias , Gaan Sabyasachi , Burgert Ingo
Published: January 2015

Sustainable societies require the development of engineered hybrid materials. Bio-inspired mineralization of the wood cell wall architecture with calcium carbonate offers a green alternative to conventional fire-retardant systems.
Shape-controllable synthesis and enhanced upconversion luminescence of Li+ doped β-NaLuF4:Yb3+,Ln3+ (Ln = Tm, Ho) microcrystals
Authors: Lin Hao , Xu Dekang , Teng Dongdong , Yang Shenghong , Zhang Yueli
Published: January 2015

UC luminescence intensities of blue and green emissions are significantly enhanced via Li+ doping.
Ambient atmosphere-processable, printable Cu electrodes for flexible device applications: structural welding on a millisecond timescale of surface oxide-free Cu nanoparticles
Authors: Oh Sang-Jin , Jo Yejin , Lee Eun Jung , Lee Sun Sook , Kang Young Hun , Jeon Hye-Ji , Cho Song Yun , Park Jin-Seong , Seo Yeong-Hui , Ryu Beyong-Hwan , Choi Youngmin , Jeong Sunho
Published: January 2015

We demonstrate Cu nanoparticle-derived printed conductive structures on plastic and paper substrates in air.
Enzymatically crosslinked alginate hydrogels with improved adhesion properties
Authors: Hou Junxia , Li Chong , Guan Ying , Zhang Yongjun , Zhu X. X.
Published: January 2015

Alginate–dopamine (Alg–DA) conjugate, a polymer with catechol side groups instead of phenol groups, gels in situ in the presence of HRP and H2O2. The resulting hydrogels exhibit significantly improved adhesion properties.
RM1 modeling of neodymium, promethium, and samarium coordination compounds
Authors: Filho Manoel A. M. , Dutra José Diogo L. , Rocha Gerd B. , Simas Alfredo M. , Freire Ricardo O.
Published: January 2015

The RM1 model is parameterized for the prediction of geometries of Nd(iii), Sm(iii), and Pm(iii) complexes.
Simultaneous determination of ascorbic acid, dopamine and uric acid at a nitrogen-doped carbon nanofiber modified electrode
Authors: Sun Jinying , Li Libo , Zhang Xueping , Liu Dong , Lv Simin , Zhu Derong , Wu Tie , You Tianyan
Published: January 2015

This paper demonstrates high electrocatalytic activity of NCNF/GCE towards small biomolecules. The proposed electrochemical sensor exhibits good selectivity, high sensitivity and excellent stability towards AA, DA and UA simultaneous detection.
A novel structural polyimide material with synergistic phosphorus and POSS for atomic oxygen resistance
Authors: Song Guanghe , Li Xuesong , Jiang Qiyang , Mu Jianxin , Jiang Zhenhua
Published: January 2015

A series of phosphorus-containing polyimide–POSS nanocomposites were synthesized, phosphorus and POSS synthetic self-passivating layers were formed to protect the underlying material from AO attack.
Combination of Ru(ii) complexes and light: new frontiers in cancer therapy
Authors: Mari Cristina , Pierroz Vanessa , Ferrari Stefano , Gasser Gilles
Published: January 2015

In this perspective article, we present the recent achievements in the application of ruthenium complexes as photosensitizers and as photoactivatable prodrugs.
Pressure-assisted CH3NH3PbI3 morphology reconstruction to improve the high performance of perovskite solar cells
Authors: Xiao Junyan , Yang Yueyong , Xu Xin , Shi Jiangjian , Zhu Lifeng , Lv Songtao , Wu Huijue , Luo Yanhong , Li Dongmei , Meng Qingbo
Published: January 2015

Hot-pressing is introduced to the fabrication of perovskite solar cells for the first time. The resulting smooth and compact CH3NH3PbI3 film can improve the performance of both HTM-free and HTM-contained solar cells.
Core cross-linked nanogels based on the self-assembly of double hydrophilic poly(2-oxazoline) block copolymers
Authors: Hartlieb Matthias , Pretzel David , Wagner Michael , Hoeppener Stephanie , Bellstedt Peter , Görlach Matthias , Englert Christoph , Kempe Kristian , Schubert Ulrich S.
Published: January 2015

The synthesis of poly(2-oxazoline)-based block copolymers consisting of a cationic and a hydrophilic segment is described.
The overlooked role of reduced graphene oxide in the reinforcement of hydrophilic polymers
Authors: Flores A. , Salavagione H. J. , Ania F. , Martínez G. , Ellis G. , Gómez-Fatou M. A.
Published: January 2015

Mechanical properties of PVA are stabilized against moisture absorption by highly hydrophobic graphene.
An n-type, new emerging luminescent polybenzodioxane polymer for application in solution-processed green emitting OLEDs
Authors: Gupta Bipin Kumar , Kedawat Garima , Kumar Pawan , Rafiee Mohammad A. , Tyagi Priyanka , Srivastava Ritu , Ajayan Pulickel M.
Published: January 2015

An n-type, newly emerging emitter with strong green luminescence and their suitability as electron transport layer for OLEDs devices is demonstrated.
Incorporating deadbeat and low‐frequency harmonic elimination in modular multilevel converters
Authors: Wang Can , Ooi Boon‐Teck
Published: January 2015

This study shows that modular multilevel converter (MMC) can implement deadbeat control and harmonic elimination together. MMC, under single‐phase deadbeat control, tracks the current reference exclusively, so that it is: (i) safe from large destructive currents of ac faults; and (ii) free from the odd harmonics generated by the non‐linearities of MMC. As a deadbeat control cannot filter even harmonics on the dc‐side, harmonic elimination has to be done by joint feedback–feedforward methods. However, the cost saving from capacitor size reduction, made possible by the harmonic elimination, comes to naught when large ac fault currents charge the capacitors to voltage levels destructive to insulated‐gate bipolar transistors. Deadbeat, in preventing the flow of large fault currents, safeguards capacitor size reduction made possible by the harmonic elimination methods. Redundant protection by the methods enhances reliability. Claims are validated by simulations by SIMULINK of MATLAB.
Optimal bidding strategy of electricity retailers using robust optimisation approach considering time‐of‐use rate demand response programs under market price uncertainties
Authors: Nojavan Sayyad , Mohammadi‐Ivatloo Behnam , Zare Kazem
Published: January 2015

In restructured electricity markets, the electricity retailers try to obtain the consumers' electricity demand at the minimum cost of different resources such as self‐generating facilities, bilateral contracts and pool market purchases. Hence, more attention should be paid to the demand response programs (DRPs) which aim to electricity procurement cost reduction. Owing to the uncertain nature of pool prices and the price fluctuation in the pool markets, the uncertainty modelling is inevitable for retailers. In this study, a robust optimisation approach is proposed for decision making of electricity retailers. Meanwhile, considering the effect of DRP on total procurement cost, an optimal bidding strategy is proposed of electricity retailers with the time‐based model of DRP in the electricity market. For this purpose, a collection of robust mixed‐integer linear programming (RMILP) problem should be solved in the proposed method. Rather than using the forecasted prices as inputs, the upper and lower limits of pool prices are considered for the uncertainty modelling. The range of pool prices is sequentially partitioned into successive nested subintervals, which permits formulating the RMILP problems. The results of these problems give sufficient data to obtain an optimal bidding strategy for electricity retailers considering DRP. Detailed analysis is performed to delineate the proposed method.
Dynamique de l'abondance des oocystes d'Isosporabellidans un milieu aquatique en zone tropicale (Cameroun)
Authors: Gideon Ajeagah , Karie Mouncharou Jean E
Published: January 2015

Une étude visant à isoler, identifier et caractériser les oocystesd'I.bellidans l'Abiergué a été menée d'avril à novembre 2011. Les échantillonnages ont été faits mensuellement dans six stations le long du cours d'eau. Les oocystes ont été identifiés par des techniques de coloration notamment la coloration de Zielh-Neelsen modifiée et celle du Lugol. Les résultats de la biologie révèlent la présence et la distribution des oocystesd'I.bellile long du cours d'eau avec une densité moyenne de 344 oocystes/L. Cette abondance résulte de la contamination par les matières fécales déversées dans l'hydrosystème à partir des latrines-canons. Les oocystes identifiés montrent une prédominance des oocystes à sporoblaste non-individualisé, en moyenne 202 oocystes/L, aussi bien au niveau spatial que saisonnier. Ce travail a mis en évidence la dominance des oocystes de petite taille avec une densité moyenne de 194 oocystes/L dans ce milieu aquatique en zone urbaine. Le calcul du coefficient de corrélation de Spearman montre des corrélations positivement significatives (p = 0,01) entre les nitrates, la turbidité et les oocystes d'une part et une corrélation négativement significative (p = 0,05) entre le CO2dissous et les oocystes d'autre part.
Simultaneous detection of refractive index and surface charges in nanolaser biosensors
Authors: Watanabe Keisuke , Kishi Yoji , Hachuda Shoji , Watanabe Takumi , Sakemoto Mai , Nishijima Yoshiaki , Baba Toshihiko
Published: January 2015

The emission intensity of a GaInAsP photonic crystal nanolaser is affected by the pH of the solution, in which the nanolaser is immersed. This phenomenon can be explained by the change in the redox potential, which modifies the filling of electrons at surface states of the semiconductor and hence the nonradiative surface recombination. This phenomenon allows the nanolaser to simultaneously and independently detect the refractive index and electric charges near the surface on the basis of the variation in emission wavelength and intensity, respectively. This paper demonstrates this function through alternate deposition of charged polyelectrolytes and hybridization of deoxyribonucleic acids.
An adaptive multi-level simulation algorithm for stochastic biological systems
Authors: Lester C. , Yates C. A. , Giles M. B. , Baker R. E.
Published: January 2015

Discrete-state, continuous-time Markov models are widely used in the modeling of biochemical reaction networks. Their complexity often precludes analytic solution, and we rely on stochastic simulation algorithms (SSA) to estimate system statistics. The Gillespie algorithm is exact, but computationally costly as it simulates every single reaction. As such, approximate stochastic simulation algorithms such as the tau-leap algorithm are often used. Potentially computationally more efficient, the system statistics generated suffer from significant bias unless tau is relatively small, in which case the computational time can be comparable to that of the Gillespie algorithm. The multi-level method [Anderson and Higham, “Multi-level Monte Carlo for continuous time Markov chains, with applications in biochemical kinetics,” SIAM Multiscale Model. Simul. 10(1), 146–179 (2012)] tackles this problem. A base estimator is computed using many (cheap) sample paths at low accuracy. The bias inherent in this estimator is then reduced using a number of corrections. Each correction term is estimated using a collection of paired sample paths where one path of each pair is generated at a higher accuracy compared to the other (and so more expensive). By sharing random variables between these paired paths, the variance of each correction estimator can be reduced. This renders the multi-level method very efficient as only a relatively small number of paired paths are required to calculate each correction term. In the original multi-level method, each sample path is simulated using the tau-leap algorithm with a fixed value of τ. This approach can result in poor performance when the reaction activity of a system changes substantially over the timescale of interest. By introducing a novel adaptive time-stepping approach where τ is chosen according to the stochastic behaviour of each sample path, we extend the applicability of the multi-level method to such cases. We demonstrate the efficiency of our method using a number of examples.
Accurate spectroscopy of polycyclic aromatic compounds: From the rotational spectrum of fluoren-9-one in the millimeter wave region to its infrared spectrum
Authors: Maris Assimo , Calabrese Camilla , Melandri Sonia , Blanco Susana
Published: January 2015

The rotational spectrum of fluoren-9-one, a small oxygenated polycyclic aromatic hydrocarbon, has been recorded and assigned in the 52-74.4 GHz region. The determined small negative value of the inertia defect (−0.3 u Å2) has been explained in terms of vibrational-rotational coupling constants calculated at the B3LYP/cc-pVTZ level of theory. Vibrational anharmonic analysis together with second-order vibrational perturbation theory approximation was applied both to fluorenone and its reduced form, fluorene, to predict the mid- and near-infrared spectra. The data presented here give precise indication on the fluorenone ground state structure, allow for an accurate spectral characterization in the millimeter wave and infrared regions, and hopefully will facilitate extensive radio astronomical searches with large radio telescopes.
Mapping of ferroelectric domain structure using angle-resolved piezoresponse force microscopy
Authors: Kim K. L. , Huber J. E.
Published: January 2015

Angle-resolved piezoresponse force microscopy (AR-PFM) was used in conjunction with electron backscatter diffraction (EBSD) to study ferroelectric domain structure in polycrystalline near-morphotropic lead zirconate titanate (PZT). We introduce the details of AR-PFM including experimental method, the process to generate AR-PFM maps, and the interpretation of AR-PFM map, using domain patterns observed in bulk PZT. The spatial distortion caused by scanner creep and non-linearity in scanning probe microscopy was corrected through image registration, taking advantage of the features present in topography images. Domain structures were mapped using AR-PFM data, and the maps consistently show alternating piezoresponse axes in a lamellar pattern of non-180° domain structure. Comparison of AR-PFM and EBSD data showed a discrepancy between the direction of lateral surface displacement and the in-plane polarization direction. Additionally, using suitable domain patterns, AR-PFM enabled discrimination between the tetragonal and rhombohedral phases at the sub-grain scale.
Nanoscale-resolved chemical identification of thin organic films using infrared near-field spectroscopy and standard Fourier transform infrared references
Authors: Mastel Stefan , Govyadinov Alexander A. , de Oliveira Thales V. A. G. , Amenabar Iban , Hillenbrand Rainer
Published: January 2015

We establish a solid basis for the interpretation of infrared near-field spectra of thin organic films on highly reflective substrates and provide guidelines for their straightforward comparison to standard far-field Fourier transform infrared (FTIR) spectra. Particularly, we study the spectral behavior of near-field absorption and near-field phase, both quantities signifying the presence of a molecular resonance. We demonstrate that the near-field phase spectra only weakly depend on the film thickness and can be used for an approximate comparison with grazing incidence FTIR (GI-FTIR) spectra. In contrast, the near-field absorption spectra can be compared more precisely with far-field spectra: for ultrathin films they match well GI-FTIR spectra, while for thick films a good agreement with standard transmission FTIR spectra is found. Our results are based on experimental data obtained by nanoscale FTIR (nano-FTIR) spectroscopy and supported by a comprehensive theoretical analysis.
Self-consistent modeling of terahertz waveguide and cavity with frequency-dependent conductivity
Authors: Huang Y. J. , Chu K. R. , Thumm M.
Published: January 2015

The surface resistance of metals, and hence the Ohmic dissipation per unit area, scales with the square root of the frequency of an incident electromagnetic wave. As is well recognized, this can lead to excessive wall losses at terahertz (THz) frequencies. On the other hand, high-frequency oscillatory motion of conduction electrons tends to mitigate the collisional damping. As a result, the classical theory predicts that metals behave more like a transparent medium at frequencies above the ultraviolet. Such a behavior difference is inherent in the AC conductivity, a frequency-dependent complex quantity commonly used to treat electromagnetics of metals at optical frequencies. The THz region falls in the gap between microwave and optical frequencies. However, metals are still commonly modeled by the DC conductivity in currently active vacuum electronics research aimed at the development of high-power THz sources (notably the gyrotron), although a small reduction of the DC conductivity due to surface roughness is sometimes included. In this study, we present a self-consistent modeling of the gyrotron interaction structures (a metallic waveguide or cavity) with the AC conductivity. The resulting waveguide attenuation constants and cavity quality factors are compared with those of the DC-conductivity model. The reduction in Ohmic losses under the AC-conductivity model is shown to be increasingly significant as the frequency reaches deeper into the THz region. Such effects are of considerable importance to THz gyrotrons for which the minimization of Ohmic losses constitutes a major design consideration.
Nitrogen-doped 9-cell cavity performance in a test cryomodule for LCLS-II
Authors: Gonnella D. , Eichhorn R. , Furuta F. , Ge M. , Hall D. , Ho V. , Hoffstaetter G. , Liepe M. , O'Connell T. , Posen S. , Quigley P. , Sears J. , Veshcherevich V. , Grassellino A. , Romanenko A. , Sergatskov D. A.
Published: January 2015

The superconducting RF linac for Linac Coherent Light Source-II calls for 1.3 GHz 9-cell cavities with an average intrinsic quality factor Q0 of 2.7 × 1010 at 2.0 K and 16 MV/m accelerating gradient. Two niobium 9 cell cavities, prepared with nitrogen-doping at Fermilab, were assembled into the Cornell Horizontal Test Cryomodule (HTC) to test cavity performance in a cryomodule that is very similar to a full LCLS-II cryomodule. The cavities met LCLS-II specifications with an average quench field of 17 MV/m and an average Q0 of 3 × 1010. The sensitivity of the cavities' residual resistance to ambient magnetic field was determined to be 0.5 nΩ/mG during fast cool down. In two cool downs, a heater attached to one of the cavity beam tubes was used to induce large horizontal temperature gradients. Here, we report on the results of these first tests of nitrogen-doped cavities in a cryomodule, which provide critical information for the LCLS-II project.
Transition among failure modes of the bending system with a stiff film on a soft substrate
Authors: Dai Longchao , Huang Yin , Chen Hang , Feng Xue , Fang Daining
Published: January 2015

Growing interest is being attracted by stretchable and flexible electronics recently due to their attractive characteristics, commercial potentials, and engineering challenges. In comparison with the system on a macroscopic scale, different failure modes are observed in a system with a thin film bonded on an elastomeric substrate. Furthermore, the experimental observations reveal that failure modes occur in turn with the increasing of thickness ratio of the film to substrate. In this paper, theoretical analysis is performed on the failure mechanism in this system with the focus on transitions among these failure modes based on the theory of fracture mechanics. The present theoretical predictions are coincident with related experiment results and can be used to guide the related structural design.
On push-forward representations in the standard gyrokinetic model
Authors: Miyato N. , Yagi M. , Scott B. D.
Published: January 2015

Two representations of fluid moments in terms of a gyro-center distribution function and gyro-center coordinates, which are called push-forward representations, are compared in the standard electrostatic gyrokinetic model. In the representation conventionally used to derive the gyrokinetic Poisson equation, the pull-back transformation of the gyro-center distribution function contains effects of the gyro-center transformation and therefore electrostatic potential fluctuations, which is described by the Poisson brackets between the distribution function and scalar functions generating the gyro-center transformation. Usually, only the lowest order solution of the generating function at first order is considered to explicitly derive the gyrokinetic Poisson equation. This is true in explicitly deriving representations of scalar fluid moments with polarization terms. One also recovers the particle diamagnetic flux at this order because it is associated with the guiding-center transformation. However, higher-order solutions are needed to derive finite Larmor radius terms of particle flux including the polarization drift flux from the conventional representation. On the other hand, the lowest order solution is sufficient for the other representation, in which the gyro-center transformation part is combined with the guiding-center one and the pull-back transformation of the distribution function does not appear.
Low frequency modulation of jets in quasigeostrophic turbulence
Authors: Suhas D. L. , Sukhatme Jai
Published: January 2015

Quasigeostrophic turbulence on a β-plane with a finite deformation radius is studied numerically, with particular emphasis on frequency and combined wavenumber-frequency domain analyses. Under suitable conditions, simulations with small-scale random forcing and large-scale drag exhibit a spontaneous formation of multiple zonal jets. The first hint of wave-like features is seen in the distribution of kinetic energy as a function of frequency; specifically, for progressively larger deformation scales, there are systematic departures in the form of isolated peaks (at progressively higher frequencies) from a power-law scaling. Concomitantly, there is an inverse flux of kinetic energy in frequency space which extends to lower frequencies for smaller deformation scales. The identification of these peaks as Rossby waves is made possible by examining the energy spectrum in frequency-zonal wavenumber and frequency-meridional wavenumber diagrams. In fact, the modified Rhines scale turns out to be a useful measure of the dominant meridional wavenumber of the modulating Rossby waves; once this is fixed, apart from a spectral peak at the origin (the steady jet), almost all the energy is contained in westward propagating disturbances that follow the theoretical Rossby dispersion relation. Quite consistently, noting that the zonal scale of the modulating waves is restricted to the first few wavenumbers, the energy spectrum is almost entirely contained within the corresponding Rossby dispersion curves on a frequency-meridional wavenumber diagram. Cases when jets do not form are also considered; once again, there is a hint of Rossby wave activity, though the spectral peaks are quite muted. Further, the kinetic energy scaling in frequency domain follows a −5/3 power-law and is distributed much more broadly in frequency-wavenumber diagrams.
Edible fat structures at high solid fat concentrations: Evidence for the existence of oil-filled nanospaces
Authors: Peyronel Fernanda , Quinn Bonnie , Marangoni Alejandro G. , Pink David A.
Published: January 2015

We have characterized the surfaces of grain boundaries in edible oils with high solid fat content by combining ultra-small angle x-ray scattering (USAXS) with theoretical modelling and computer simulation. Our results will lead to understand the solid structures formed at the time of manufacturing fats like confectionery fats as well as pave the way for the engineering of innovative fat products. Edible fats are complex semi-solid materials where a solid structure entraps liquid oil. It was not until USAXS combined with modelling was used that the nano- to meso-structures for systems with less than 20% solids were understood. The interpretation of those results utilized models of crystalline nanoplatelets represented by rigid close-packed flat aggregates made of spheres and was allowed to aggregate using the Metropolis Monte Carlo technique. Here, we report on systems containing between 50% and 90% solids. We modelled the solid phase as being formed from seeds onto which solids condensed thereby giving rise to oil-filled nanospaces. The models predicted that the system (a) exhibits structures with fractal dimensions approximately 2, (b) a broad peak somewhat masking that slope, and (c) for smaller values of q, indications that the structures with fractal dimension approximately 2 are uniformly distributed in space. The interpretation of the experimental data was completely driven by these results. The computer simulation predictions were used in conjunction with the USAXS observations to conclude that the systems studied scattered from oil-cavities with sizes between ∼800 and ∼16 000 Å and possessed rough 2-dimensional walls.
High-performance AlGaN metal–semiconductor–metal solar-blind ultraviolet photodetectors by localized surface plasmon enhancement
Authors: Zhang Wei , Xu Jin , Ye Wei , Li Yang , Qi Zhiqiang , Dai Jiangnan , Wu Zhihao , Chen Changqing , Yin Jun , Li Jing , Jiang Hao , Fang Yanyan
Published: January 2015

AlGaN-based solar-blind ultraviolet photodetectors have attractive potential applications in the fields of missile plume detection, biochemical sensing, solar astronomy, etc. In this work, significant deep ultraviolet detection enhancement is demonstrated on AlGaN-based metal–semiconductor–metal (MSM) solar-blind ultraviolet photodetectors by introducing the coupling of localized surface plasmon from Al nanoparticles with the high-Al-content AlGaN epilayer. The size-controlled Al nanoparticle arrays fabricated by nanosphere lithography can not only reduce the detectors' dark current but also bring about greatly enhanced responsivity. The peak responsivity of AlGaN-based MSM solar-blind ultraviolet photodetectors with Al nanoparticles can reach 2.34 A/W at 269 nm under 20 V bias, enhanced more than 25 times than that without Al nanoparticles. Our approach shows an efficient fabrication technique of high-performance and low-cost plasmonic enhanced AlGaN solar-blind MSM ultraviolet photodetectors.
Gigahertz single-hole transfer in Si tunable-barrier pumps
Authors: Yamahata Gento , Karasawa Takeshi , Fujiwara Akira
Published: January 2015

We report high-speed single-hole (SH) transfer using Si tunable-barrier pumps comprising p-type metal-oxide-semiconductor field-effect transistors. A clear SH-transfer-current plateau with the current level of about 160 pA was observed when a clock signal having a frequency of 1 GHz was applied to one of the gates. Temperature dependence measurements of the transfer current reveal that the transfer probability is dominated by non-equilibrium SH escape by thermal hopping from the electrically formed charge island. The lower bound of the relative error rate for the 1-GHz transfer is about 10−3 at a temperature of about 17 K. In addition, we investigate the frequency dependence of the transfer, where we discuss possible sources causing the change in the error rate. These results pave the way for accurate manipulation of SHs and its application to metrological current standards.
Physical and virtual water transfers for regional water stress alleviation in China
Authors: Zhao Xu , Liu Junguo , Liu Qingying , Tillotson Martin R. , Guan Dabo , Hubacek Klaus
Published: January 2015

Significance

Freshwater resources are unevenly distributed in China. This situation drives a significant amount of water flow both physically and virtually across China. Here, we report on our quantification of China’s physical and virtual water flows and associated water stress at the provincial level. In 2007, interprovincial physical water flows amounted to only a small part of China’s total water supply, but virtual water flows amounted to over one-third of supply. We found that both physical and virtual water flows exacerbated water stress for the main water-exporting provinces. The results highlight the need for more emphasis to be placed on water demand management rather than the current focus on supply-oriented management.