bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of clinical score to stage and predict outcome of hepatic resection of metastatic colorectal cancer
Authors: Feroci Francesco , Fong Yuman
Published: December 2010

All metastatic colorectal cancer cases are classified as stage IV by AJCC staging, yet cases differ widely as to prognosis. Criteria are needed to select patients for surgery, for adjuvant therapy, and for clinical trials. In this paper we review the various prognostic scoring systems proposed, including the most widely used clinical risk score. Validation and practical uses of these scoring systems are also discussed. J. Surg. Oncol. 2010;102:914–921. © 2010 Wiley‐Liss, Inc.
Role of intra‐arterial hepatic chemotherapy in the treatment of colorectal cancer metastases
Authors: Kingham T. Peter , D'Angelica Michael , Kemeny Nancy E.
Published: December 2010

Hepatic metastases are common with colorectal cancer. The primary blood supply to hepatic metastases is the hepatic artery. Regional chemotherapy utilizing the hepatic artery is one treatment option for liver metastases. The advantage of hepatic arterial chemotherapy is that high concentrations of the therapeutic drug are obtained in the liver with minimal systemic toxicity. Recently, systemic chemotherapy regimens have been added to hepatic arterial infusional chemotherapy to treat hepatic metastases. Due to the high response rates in the liver, resection rates are increasing in patients originally thought to have unresectable liver disease. Hepatic arterial chemotherapy has also been used in the adjuvant setting after resection of all liver metastases in order to minimize hepatic recurrences. The role of hepatic arterial infusional therapy in treating hepatic colorectal metastases includes treating patients with both resectable and unresectable metastases in the adjuvant, neoadjuvant, or palliative settings. J. Surg. Oncol. 2010;102:988–995. © 2010 Wiley‐Liss, Inc.
Topology optimization for nano‐photonics
Authors: Jensen J.S. , Sigmund O.
Published: December 2010

Topology optimization is a computational tool that can be used for the systematic design of photonic crystals, waveguides, resonators, filters and plasmonics. The method was originally developed for mechanical design problems but has within the last six years been applied to a range of photonics applications. Topology optimization may be based on finite element and finite difference type modeling methods in both frequency and time domain. The basic idea is that the material density of each element or grid point is a design variable, hence the geometry is parameterized in a pixel‐like fashion. The optimization problem is efficiently solved using mathematical programming‐based optimization methods and analytical gradient calculations. The paper reviews the basic procedures behind topology optimization, a large number of applications ranging from photonic crystal design to surface plasmonic devices, and lists some of the future challenges in non‐linear applications.
Current mass spectrometry strategies for the analysis of pesticides and their metabolites in food and water matrices
Authors: Botitsi Helen V. , Garbis Spiros D. , Economou Anastasios , Tsipi Despina F.
Published: December 2010

Analysis of pesticides and their metabolites in food and water matrices continues to be an active research area closely related to food safety and environmental issues. This review discusses the most widely applied mass spectrometric (MS) approaches to pesticide residues analysis over the last few years. The main techniques for sample preparation remain solvent extraction and solid‐phase extraction. The QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) approach is being increasingly used for the development of multi‐class pesticide residues methods in various sample matrices. MS detectors—triple quadrupole (QqQ), ion‐trap (IT), quadrupole linear ion trap (QqLIT), time‐of‐flight (TOF), and quadrupole time‐of‐flight (QqTOF)—have been established as powerful analytical tools sharing a primary role in the detection/quantification and/or identification/confirmation of pesticides and their metabolites. Recent developments in analytical instrumentation have enabled coupling of ultra‐performance liquid chromatography (UPLC) and fast gas chromatography (GC) with MS detectors, and faster analysis for a greater number of pesticides. The newly developed “ambient‐ionization” MS techniques (e.g., desorption electrospray ionization, DESI, and direct analysis in real time, DART) hyphenated with high‐resolution MS platforms without liquid chromatography separation, and sometimes with minimum pre‐treatment, have shown potential for pesticide residue screening. The recently introduced Orbitrap mass spectrometers can provide high resolving power and mass accuracy, to tackle complex analytical problems involved in pesticide residue analysis. © 2010 Wiley Periodicals, Inc., Mass Spec Rev 30:907–939, 2011
Net boss: The color graphic network manager for the vtam environment
Authors: Burke Bernie
Published: December 2010

This paper focuses on the need to eliminate disastrous data center situations through the ability to easily monitor the entire VTAM network. This article introduces NetBoss, a strategic tool developed and marketed by Allen Systems Group, Inc., as one of the solutions.
A discontinuous enrichment method for variable‐coefficient advection–diffusion at high Péclet number
Authors: Kalashnikova I. , Tezaur R. , Farhat C.
Published: December 2010

A discontinuous Galerkin method with Lagrange multipliers is presented for the solution of variable‐coefficient advection–diffusion problems at high Péclet number. In this method, the standard finite element polynomial approximation is enriched within each element with free‐space solutions of a local, constant‐coefficient, homogeneous counterpart of the governing partial differential equation. Hence in the two‐dimensional case, the enrichment functions are exponentials, each exhibiting a sharp gradient in a carefully chosen flow direction. The continuity of the enriched approximation across the element interfaces is enforced weakly by the aforementioned Lagrange multipliers. Numerical results obtained for two benchmark problems demonstrate that elements based on the proposed discretization method are far more competitive for variable‐coefficient advection–diffusion analysis in the high Péclet number regime than their standard Galerkin and stabilized finite element comparables. Copyright © 2010 John Wiley & Sons, Ltd.
Increasing rates of breast cancer and cardiac surveillance among high‐risk survivors of childhood Hodgkin lymphoma following a mailed, one‐page survivorship care plan
Authors: Oeffinger Kevin C. , Hudson Melissa M. , Mertens Ann C. , Smith Stephanie M. , Mitby Pauline A. , Eshelman‐Kent Debra A. , Ford Jennifer S. , Jones Judith K. , Kamani Sharmila , Robison Leslie L.
Published: December 2010

Background

Hodgkin lymphoma (HL) survivors face substantially elevated risks of breast cancer and cardiovascular disease. They and their physicians are often unaware of these risks and surveillance recommendations.

Procedure

A prospective one‐arm study was conducted among a random sample of 72 HL survivors, ages 27–55 years, participating in the Childhood Cancer Survivor Study (CCSS) who were at increased risk for breast cancer and/or cardiomyopathy and had not had a screening mammogram or echocardiogram, respectively, within the prior 2 years. A one‐page survivorship care plan with recommendations for surveillance was mailed to participants. In addition, survivors' primary physicians were contacted and provided patient‐specific information and a web‐based Virtual Information Center was made available for both survivors and physicians. Outcomes were assessed by telephone 6 months after the intervention.

Results

The survivor participation (62/72; 86%) and 6‐month retention (56/61; 92%) rates were high. Tension and anxiety, measured by the Profile of Mood States, did not increase following risk notification; 91% of survivors described their reactions to receiving the information in positive terms. At 6 months, 41% of survivors reported having completed the recommended mammogram; 20% reported having an echocardiogram (females 30%, males 10%). Only 29% of survivors visited the website. Nine physicians enrolled, and none used the study resources.

Conclusion

A mailed, personalized survivorship care plan was effective in communicating risk and increasing compliance with recommended medical surveillance. Internet‐ and telephone‐based strategies to communicate risk were not utilized by survivors or physicians. Pediatr Blood Cancer 2011;56:818–824. © 2011 Wiley‐Liss, Inc.
Development and reliability of the comprehensive crisis plan checklist
Authors: Aspiranti Kathleen B. , Pelchar Taylor K. , McCLeary Daniel F. , Bain Sherry K. , Foster Lisa N.
Published: December 2010

It is of vital importance that children are educated in a safe environment. Every school needs to have a well‐developed crisis management document containing plans for prevention, intervention, and postvention. We developed the Comprehensive Crisis Plan Checklist (CCPC) to serve as a valuable tool that can be used to assist practitioners with evaluation of their school crisis management plans. To use the CCPC, school personnel should match the items on the checklist to elements in their developing or existing crisis plan to determine missing elements. By comparing a school or district crisis plan to the CCPC, practitioners or school personnel will be able to determine strengths and weaknesses of the plan as well as provide feedback for making their plans more complete and comprehensive. In this study, we describe the development of the CCPC and report on reliability data using this checklist. © 2010 Wiley Periodicals, Inc.
Insights into the conformational flexibility of Bruton's tyrosine kinase from multiple ligand complex structures
Authors: Kuglstatter Andreas , Wong April , Tsing Stan , Lee Simon W. , Lou Yan , Villaseñor Armando G. , Bradshaw J. Michael , Shaw David , Barnett Jim W. , Browner Michelle F.
Published: December 2010

Bruton's tyrosine kinase (BTK) plays a key role in B cell receptor signaling and is considered a promising drug target for lymphoma and inflammatory diseases. We have determined the X‐ray crystal structures of BTK kinase domain in complex with six inhibitors from distinct chemical classes. Five different BTK protein conformations are stabilized by the bound inhibitors, providing insights into the structural flexibility of the Gly‐rich loop, helix C, the DFG sequence, and activation loop. The conformational changes occur independent of activation loop phosphorylation and do not correlate with the structurally unchanged WEI motif in the Src homology 2‐kinase domain linker. Two novel activation loop conformations and an atypical DFG conformation are observed representing unique inactive states of BTK. Two regions within the activation loop are shown to structurally transform between 310‐ and α‐helices, one of which collapses into the adenosine‐5′‐triphosphate binding pocket. The first crystal structure of a Tec kinase family member in the pharmacologically important DFG‐out conformation and bound to a type II kinase inhibitor is described. The different protein conformations observed provide insights into the structural flexibility of BTK, the molecular basis of its regulation, and the structure‐based design of specific inhibitors.
Spatially resolved Raman and cathodoluminescence probes in electronic materials: Basics and applications
Authors: Pezzotti Giuseppe
Published: December 2010

Spatially resolved spectroscopy of both Raman and cathodoluminescence (CL) emissions represent a quite powerful characterization method in electronics. In this paper, the underlying physics that dictates the different characteristics of Raman and CL probes is revisited, deepened, and further interpreted in order to clarify how the different nature of those probes enables one bringing about different sets of complementary information. Furthermore, it is inquired into the causes for which data collected by the two different spectroscopic methods on the same material or device may, at a first glance, appear inconsistent to each other and, for some aspects, contradictory. Such differences and contradictions are then shown to disappear once the different nature of the two probes, especially with respect to their spatial response and morphology, is clarified and properly taken into account. Emphasis is finally placed on quantitatively describing the spatial response of Raman and CL probes and to apply such knowledge to elucidate the behavior of electronic materials. The two types of light emission are described according to a common formalism, which details their respective probe response functions in the three‐dimensional space. Practical applications of Raman and CL spectroscopy to resolve highly graded fields of crystal orientation and elastic stress/strain in paradigm electronic materials are finally shown and compared.
Diffusion length determination in solar grade silicon by room temperature photoluminescence measurements
Authors: Sayad Y. , Blanc D. , Kaminski A. , Bremond G. , Lemiti M.
Published: December 2010

Minority carrier lifetime (τ) and diffusion length (L) are the most important electrical parameters to qualify silicon for photovoltaic applications. Amongst the available techniques for measuring this parameter, photoluminescence has regained interest as it can be done on raw material as well as on completed solar cells in a non destructive way. Although very efficient mapping systems can provide fast information on multicrystalline samples most quantitative measurements require a calibration that is normally achieved by correlation with other techniques like photoconductance decay. In this paper, we show that L may be evaluated in a simple way from the dependence of the room temperature photoluminescence signal on the excitation beam intensity using an analytical model based on 1D carrier diffusion. Using this 1D model, the diffusion length was calculated in photovoltaic grade silicon materials without calibration by external technique. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical properties of polysilicon nanowires for device applications
Authors: Demami F. , Rogel R. , Salaün A.‐C. , Pichon L.
Published: December 2010

Polysilicon nanowires are synthesized using the well known and low cost technique commonly used in microelectronic industry: the sidewall spacer formation technique. Polysilicon layer is deposited by Low Pressure Chemical Vapour Deposition technique on SiO2 wall patterned by conventional UV lithography technique. Polysilicon film is then plasma etched. Accurate control of the etching rate leads to the formation of nanometric size sidewall spacers with a curvature radius as low as 100 nm used as polysilicon nanowires. These polysilicon nanowires are first integrated into the fabrication of electrical devices as resistors and electrical properties are studied in function of in situ phosphorus doping levels. I(T) measurements show that polysilicon nanowires dark conductivity is thermally activated according to the Seto's theory. In addition, field effect transistors made with such polysilicon nanowires used as channel region highlight promising field effect behaviour. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth rate model and doping metrology by atom probe tomography in silicon nanowire
Authors: Chen W. H. , Lardé R. , Cadel E. , Xu T. , Grandidier B. , Nys J. P. , Stiévenard D. , Pareige P.
Published: December 2010

Silicon nanowires (SiNWs) with different surface number density are fabricated using Chemical Vapor Deposition (CVD) method by controlling the catalyst droplet number density with in‐situ evaporation. For comparison, another type of SiNWs is fabricated by Molecular Beam Epitaxy (MBE) method. To study these two types of SiNWs a general growth rate model is presented. The fit curves from this model are consistent with our experimental data. In both growing conditions the SiNW growth rate as a function of their diameter are compared and discussed. The p‐type SiNWs have also been prepared by adding diborane into precursor. The doping metrology in an individual SiNW is realized by laser assisted Atom Probe Tomography (APT). We have shown that the doping atoms (e.g. B) can incorporate into SiNW and an accurate quantification can be given (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analytical modelling and experimental verification of the three‐dimensional current distribution on the top surface of silicon solar cells operating under concentrated sunlight
Authors: Costagliola Maurizio , Riccio Michele , Irace Andrea , Breglio Gianluca , Daliento Santolo
Published: December 2010

The approximation that the current is constant in any point of the emitter is not true for solar cells operating under concentrated sunlight. The transverse paths followed by photogenerated carriers to reach metal grid electrodes causes voltage drops leading to non‐uniform distributed surface potential and a consequent reduction of the conversion efficiency. Moreover, concentrating lens often provide non‐uniform light intensity thus worsening non‐uniform current distribution. The correct design of surface geometry of the cell (metal grid, emitter depth, sheet resistance) should always take into account the above effects. Unfortunately a lack of reliable models still exists. In this paper we analytically solve the three‐dimensional semiconductor equations with proper boundary conditions and taking into account, as source term, a distributed generation contribute. The reliability of the model has been tested by numerical simulations and experimentally verified with a lock‐in thermography technique (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stimulated emission from anthracene aggregates in fluorene crystals fabricated by cell method
Authors: Mizuno Hitoshi , Aoki‐Matsumoto Tamao , Ichida Masao , Ando Hiroaki , Hirai Takeshi , Mizuno Ken‐ichi
Published: December 2010

In fluorene(80%)–anthracene(20%) mixed crystals, mainly observed luminescence is broad D2 bands, which originates from an excitation state localized on two anthracene molecules and is accompanied by lattice relaxation. Under high intensity excitation, several sharp luminescence lines emerged in the high energy side of the D2 0–1 bands and their intensity increased superlinearly with excitation intensity. The decay time of the luminescence lines is 30 ps, which is two orders of magnitude smaller than decay time under low intensity excitation. These results suggest that sharp luminescence lines are stimulated luminescence from D2 centers. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mathematical model of the occurrence of human error in manufacturing processes
Authors: Myszewski Jan M.
Published: December 2010

Various types of phenomena contribute to the variability of process results. Their common feature is randomness. Some of them can be described by continuous probability distributions, for example, the performance of machines or the properties of processed material. There are also discretely distributed contributions, such as human errors or machine failures. Six sigma methodology encompasses both continuous and discrete phenomena by expressing measures of variability by the so‐called ‘sigma measure’. However, this methodology cannot be used directly to assess the individual impact of a specific class of factors, such as human errors in a continuously distributed production process. This paper describes the development of a probabilistic model of human error. The model makes use of classical reliability concepts, such as a failure rate function, to represent substantial phenomena of various types (continuous and discrete) that play a significant role in the creation of errors in human work. The model includes a mechanism that is inherently associated with human work (i.e. the ‘bathtub curve’ that represents the processes of learning and fatiguing) and mechanisms introduced by the work environment (accumulation of tasks). The hypothesis is formulated that, in industrial processes, special causes of errors are closely related to the assignment of inadequate amounts of time for properly performing the operations. Graphs of error rate functions enable intuitive graphical interpretation of the causes of problems, and they can be used to support some considerations regarding the organization and measurement of workflow during a work shift. Thus, an intuitive graph can be useful for figuring out the potential impact on the risk of errors that will result from certain system events. Such graphs can be applied in a general capability study of a process to assess the variability measures associated with the individual impacts of particular classes of factors, for example, the sigma measure used in the six sigma methodology. It can be used to identify mechanisms of potential failures associated with human error in risk analysis, such as FMEA (Failure Mode and Effect Analysis). Copyright © 2010 John Wiley & Sons, Ltd.
Multiple correspondence discriminant analysis: An application to detect stratification in copy number variation
Authors: Caceres, Alejandro , Basagaña Xavier , Gonzalez Juan R.
Published: December 2010

We illustrate the use of multiple correspondence analysis (MCA) to correct for population stratification of copy number alteration data. In addition, we propose the use of multiple correspondence discriminant analysis (MCDA) to identify an optimal set of copy number variants (CNVs) that correctly infers the population stratification of a CNV map. Within MCDA, we highlight the novel use of correlation with class directions for variable ranking. We found a set of 20 CNVs with 98 per cent predictability in a CNV map of the HapMap populations. On this sample, the selection of variables based on centroid ranking outperformed the most common practice of ranking variables with their correlation to the principal axes. Copyright © 2010 John Wiley & Sons, Ltd.
Animal visual perception
Authors: Mascalzoni Elena , Regolin Lucia
Published: December 2010

Perception processes can be investigated at the physical (concerning the stimulation from the environment to the receptors), physiological (the processes taking place in the neural system), and psychological (the ‘sense’ of perception, the outcome produced by the physical stimulation and the physiological processes) level. The present paper focuses on visual perception, mainly from a psychological level of investigation, and revises comparative literature, highlighting both similarities and differences in the visual structures and functions in different animal classes. For this purpose, the structure of the current eyes is described in a comparative perspective, as well as perceptual organization and object recognition processes, color perception, three‐dimensional structuring of the image, and motion perception. Finally, the literature about comparative susceptibility to various visual illusions will be discussed, as illusory perception has been revealed to be a most useful tool to unveil the perceptual algorithms shared by the different species. In spite of major differences between animal species in the structures in charge of perception and in the adaptations to specific ecological niches, experimental data presented here will lead to the conclusion that a number of basic perceptual principles of organization and functioning are shared between species. WIREs Cogn Sci 2011 2 106–116 DOI: 10.1002/wcs.97

This article is categorized under:

Cognitive Biology > Evolutionary Roots of Cognition

Psychology > Comparative Psychology

Psychology > Perception and Psychophysics
On the dynamical theory of thermoelastic simple shells
Authors: Bîrsan M. , Altenbach H.
Published: December 2010

In this paper we present a mathematical study of the equations of motion for orthotropic thermoelastic simple shells. We use a direct approach to the mechanics of thin shells, in which the shell‐like body is modeled as a deformable surface endowed with a triad of orthonormal vectors connected with each material point. The thermal effects are described by introducing two temperature fields which represent the temperature on the two major faces of the three‐dimensional shell. In the framework of the linear theory, we establish first the uniqueness of solution to the associated boundary–initial–value problem. Then we prove the properties of reciprocity, we give a variational characterization, and we investigate the continuous dependence of solutions on the external data. Finally, we present an existence result for the weak solutions to the equations of motion of thermoelastic simple shells.
A superconvergent scheme for a locking‐free FEM in a Timoshenko optimal control problem
Authors: Hernández E. , Otárola E.
Published: December 2010

In this work we analyze the numerical approximation of an optimal control problem of a Timoshenko beam, by considering two kinds of distributed control. The discretization of the control variables is performed by using piecewise constant functions. The states and the adjoint states are approximated by a locking free scheme of linear finite elements. An interpolation postprocessing technique is used for the approximations of the optimal solution of the continuous optimal control problem. It is proved that these approximations have superconvergence order h2, which do not depend on the thickness of the beam.
Diabetes mellitus, cachexia and obesity in heart failure: rationale and design of the Studies Investigating Co‐morbidities Aggravating Heart Failure (SICA‐HF)
Authors: von Haehling Stephan , Lainscak Mitja , Doehner Wolfram , Ponikowski Piotr , Rosano Giuseppe , Jordan Jens , Rozentryt Piotr , Rauchhaus Mathias , Karpov Rostislav , Tkachuk Vsevolod , Parfyonova Yelena , Zaritskey Andrey Y. , Shlyakhto Eugeniy V. , Cleland John G. , Anker Stefan D.
Published: December 2010

Background

Chronic heart failure (CHF) is increasing in prevalence. Patients with CHF usually have co‐morbid conditions, but these have been subjected to little research and consequently there is a paucity of guidance on how to manage them. Obesity and diabetes mellitus are common antecedents of CHF and often complicate management and influence outcome. Cachexia is an ominous and often missed sign in patients with CHF.

Methods

This manuscript describes the rationale and the design of Studies Investigating Co‐morbidities Aggravating Heart Failure (SICA‐HF), a prospective, multicentre, multinational, longitudinal, pathophysiological evaluation study, which is being conducted in 11 centres across six countries in the European Union and in Russia. We aim to recruit >1,600 patients with CHF due to various common aetiologies, irrespective of left ventricular ejection fraction, and with or without co‐morbidities at study entry. In addition, >300 patients with type 2 diabetes mellitus without CHF and >150 healthy subjects will serve as control groups. Participants will be systematically investigated at annual intervals for up to 48 months. Additional investigations focusing on cellular and subcellular mechanisms, adipose and skeletal muscle tissue, and in endothelial progenitor cells will be performed in selected subgroups.

Conclusions

SICA‐HF will provide insights into common co‐morbidities in CHF with a specific emphasis on diabetes mellitus and body mass. This will provide a more thorough pathophysiological understanding of the complexity of CHF that will help develop therapies tailored to manage specific co‐morbidities.
Pathophysiology and treatment of inflammatory anorexia in chronic disease
Authors: Braun Theodore P. , Marks Daniel L.
Published: December 2010

Decreased appetite and involuntary weight loss are common occurrences in chronic disease and have a negative impact on both quality of life and eventual mortality. Weight loss in chronic disease comes from both fat and lean mass, and is known as cachexia. Both alterations in appetite and body weight loss occur in a wide variety of diseases, including cancer, heart failure, renal failure, chronic obstructive pulmonary disease and HIV. An increase in circulating inflammatory cytokines has been implicated as a uniting pathogenic mechanism of cachexia and associated anorexia. One of the targets of inflammatory mediators is the central nervous system, and in particular feeding centers in the hypothalamus located in the ventral diencephalon. Current research has begun to elucidate the mechanisms by which inflammation reaches the hypothalamus, and the neural substrates underlying inflammatory anorexia. Research into these neural mechanisms has suggested new therapeutic possibilities, which have produced promising results in preclinical and clinical trials. This review will discuss inflammatory signaling in the hypothalamus that mediates anorexia, and the opportunities for therapeutic intervention that these mechanisms present.
Radiative transfer modeling of near‐infrared reflectance of lunar highland and mare soils
Authors: Cahill J. T. S. , Lucey P. G. , Stockstill‐Cahill K. R. , Hawke B. R.
Published: December 2010

With near‐infrared hyperspectral data sets returned from KAGUYA/SELENE and Chandrayaan‐1's Moon Mineralogic Mapper (M3), accurate evaluation and interpretation of lunar data sets with higher spectral resolution has never been more critical. Here we test a new radiative transfer spectral modeling algorithm to determine composition from hyperspectral reflectance spectra of lunar soils. Data for 19 lunar mare and highland soil samples previously characterized by the Lunar Soil Characterization Consortium are used for validation. Spectral fits are made using a goodness of fit metric considering spectral shape, spectral contrast, spectral slope, and iron abundance. High precision fits are achieved for nearly every soil with this algorithm. Using a plot of spectral shape relative to the ratio Mg′ (i.e., molar (Mg/(Mg + Fe)) × 100) determines the winning model and composition. Mg′ is determined with an average difference of ∼11–15 and ∼3–8 units before and after a correction is applied, respectively. Mineralogy is determined with an average difference of ∼5–15 vol% depending upon the mineral constituent.
Relationship between aerosol oxidation level and hygroscopic properties of laboratory generated secondary organic aerosol (SOA) particles
Authors: Massoli P. , Lambe A. T. , Ahern A. T. , Williams L. R. , Ehn M. , Mikkilä J. , Canagaratna M. R. , Brune W. H. , Onasch T. B. , Jayne J. T. , Petäjä T. , Kulmala M. , Laaksonen A. , Kolb C. E. , Davidovits P. , Worsnop D. R.
Published: December 2010

Laboratory experiments investigated the relationship between oxidation level and hygroscopic properties of secondary organic aerosol (SOA) particles generated via OH radical oxidation in an aerosol flow reactor. The hygroscopic growth factor at 90% RH (HGF90%), the CCN activity (κORG,CCN) and the level of oxidation (atomic O:C ratio) of the SOA particles were measured. Both HGF90% and κORG,CCN increased with O:C; the HGF90% varied linearly with O:C, while κORG,CCN mostly followed a nonlinear trend. An average HGF90% of 1.25 and κORG,CCN of 0.19 were measured for O:C of 0.65, in agreement with results reported for ambient data. The κORG values estimated from the HGF90% (κORG,HGF) were 20 to 50% lower than paired κORG,CCN values for all SOA particles except 1,3,5‐trimethylbenzene (TMB), the least hygroscopic of the SOA systems. Within the limitations of instrumental capabilities, we show that differences in hygroscopic behavior among the investigated SOA systems may correspond to differences in elemental composition.
Air‐density‐dependent model for analysis of air heating associated with streamers, leaders, and transient luminous events
Authors: Riousset Jeremy A. , Pasko Victor P. , Bourdon Anne
Published: December 2010

Blue and gigantic jets are transient luminous events in the middle atmosphere that form when conventional lightning leaders escape upward from the thundercloud. The conditions in the Earth's atmosphere (i.e., air density, reduced electric field, etc.) leading to conversion of hot leader channels driven by thermal ionization near cloud tops to nonthermal streamer forms observed at higher altitudes are not understood at present. This paper presents a formulation of a streamer‐to‐spark transition model that allows studies of gas dynamics and chemical kinetics involved in heating of air in streamer channels for a given air density N under assumption of constant applied electric field E. The model accounts for the dynamic expansion of the heated air in the streamer channel and resultant effects of E/N variations on plasma kinetics, the vibrational excitation of nitrogen molecules N2(v), effects of gains in electron energy in collisions with N2(v), and associative ionization processes involving N2(A3Σu+) and N2(a′1Σu−) species. The results are in excellent agreement with available experimental data at ground and near‐ground air pressures and demonstrate that for the air densities corresponding to 0–70 km altitudes the kinetic effects lead to a significant acceleration of the heating, with effective heating times scaling closer to 1/N than to 1/N2 predicted on the basis of similarity laws for Joule heating. This acceleration is attributed to a strong reduction in electron losses due to three‐body attachment and electron‐ion recombination processes with reduction of air pressure.
Decomposing observations of high‐frequency radar‐derived surface currents by their forcing mechanisms: Locally wind‐driven surface currents
Authors: Kim Sung Yong , Cornuelle Bruce D. , Terrill Eric J.
Published: December 2010

The wind impulse response function and transfer function for high‐frequency radar‐derived surface currents off southern San Diego are calculated using several local wind observations. The spatial map of the transfer function reflects the influence of the coast on wind‐current dynamics. Near the coast (within 20 km from the shoreline), the amplitudes of the transfer function at inertial and diurnal frequencies are reduced due to effects of coastline and bottom bathymetry. Meanwhile, the amplitude of low‐frequency currents increases near the coast, which is attributed to the local geostrophic balance between cross‐shore pressure gradients against the coast and currents. Locally wind‐driven surface currents are estimated from the data‐derived response function, and their power spectrum shows a strong diurnal peak superposed on a red spectrum, similar to the spectra of observed winds. Current magnitudes and veering angles to a quasi‐steady wind are typically 2–5% of the wind speed and vary 50°–90° to the right of the wind, respectively. A wind skill map is introduced to present the fractional variance of surface currents explained by local winds as a verification tool for wind data quality and relevance. Moreover, the transfer functions in summer and winter are presented to examine the seasonal variation in ocean surface current response to the wind associated with stratification change.
On the emergence of an Arctic amplification signal in terrestrial Arctic snow extent
Authors: Ghatak Debjani , Frei Allan , Gong Gavin , Stroeve Julienne , Robinson David
Published: December 2010

The impact of declining sea ice in amplifying surface air temperatures (SAT) over the Arctic Ocean is readily visible, and this “Arctic amplification” will become more pronounced as more sea ice is lost in the coming decades. The effect of sea ice loss on atmospheric temperatures and circulation patterns is of utmost significance as these changes will affect the terrestrial climate. Land‐surface snow is vulnerable to these changes; hence, we search for any link between changes in Arctic sea ice and Northern Hemisphere snow cover. Analyses of observational data sets suggest that the increasing snow cover over Siberia during fall and early winter is correlated with the decreasing September Arctic sea ice over the Pacific sector. We also examine modeled covariance between sea ice and snow using historical and future simulations of the Community Climate System Model (CCSM3). Results indicate the emergence of a Siberian snow signal during the last half of the 21st century most strongly during late winter. Moreover, CCSM3 future simulations show diminishment of snow at a hemispheric scale outside of the Siberian region, which is correlated with the loss of Arctic sea ice. These results indicate that we may be seeing the first, albeit weak, signs of “Arctic amplification” on the terrestrial Arctic snowpack; that only a weak and therefore inconclusive signal would be expected at this time; and that the signal should strengthen over the coming decades.
Laboratory studies on optical properties of secondary organic aerosols generated during the photooxidation of toluene and the ozonolysis of α‐pinene
Authors: Nakayama Tomoki , Matsumi Yutaka , Sato Kei , Imamura Takashi , Yamazaki Akihiro , Uchiyama Akihiro
Published: December 2010

It has recently been suggested that some organic aerosols can absorb solar radiation, especially at the shorter visible and UV wavelengths. Although quantitative characterization of the optical properties of secondary organic aerosols (SOAs) is required in order to confirm the effect of SOAs on the atmospheric radiation balance, the light absorption of SOAs has not yet been thoroughly investigated. In this study, we conducted laboratory experiments to measure the optical properties of SOAs generated during the photooxidation of toluene in the presence of NOx and the ozonolysis of α‐pinene. Extinction and scattering coefficients of the SOAs were measured by a cavity ring‐down aerosol extinction spectrometer and an integrating nephelometer, respectively. Refractive indices of the SOAs were determined so that the measured particle size dependence of the extinction and scattering efficiencies could be reproduced by calculations using Mie scattering theory. As a result, significant light absorption was found at 355 nm for the toluene SOAs. In contrast, no significant absorption was found either at 355 or 532 nm for the α‐pinene SOAs. Using the obtained refractive index, mass absorption cross‐section values of the toluene SOAs were calculated to be 0.3–3 m2 g−1 at 355 nm. The results indicate that light absorption by the SOAs formed from the photooxidation of aromatic hydrocarbons have a potential to influence the total aerosol light absorption, especially at UV wavelengths.
Vapor flux by evapotranspiration: Effects of changes in climate, land use, and water use
Authors: Asokan Shilpa M. , Jarsjö Jerker , Destouni Georgia
Published: December 2010

Enhanced evapotranspiration (ET) over irrigated land and associated latent heat flux change can modify the climate. Model studies of such climate change effects of irrigation are commonly based on land use parameterizations, in terms of irrigated land area, or land area equipped for irrigation. Actual ET change, however, may also be driven by water use change in addition to land use change. This study quantifies and compares ET changes due to changes in climate, land use, and water use from the preirrigation period 1901–1955 to the recent period 1990–2000 (with irrigation) for the example case of Mahanadi River Basin (MRB) in India. The results show that actual water use per unit area of irrigated land may vary greatly over a hydrological drainage basin. In MRB, much higher water use per irrigated land unit in the downstream humid basin parts leads to higher vapor flux by ET, and irrigation‐induced ET flux change, than in the upstream, water‐stressed basin parts. This is consistent with water supply limitations in water‐stressed basins. In contrast, the assumption in land use−based models that irrigation maintains high soil moisture contents can imply higher modeled water use and therefore also higher modeled ET fluxes under dry conditions than under humid conditions. The present results indicate water use as an important driver of regional climate change, in addition to land use and greenhouse gas‐driven changes.
Authigenic phyllosilicates in modern acid saline lake sediments and implications for Mars
Authors: Story Stacy , Bowen Brenda Beitler , Benison Kathleen Counter , Schulze Darrell G.
Published: December 2010

Aluminum‐ and Fe/Mg‐phyllosilicates are considered important geochemical indicators in terrestrial and Martian sedimentary systems. Traditionally, Al‐phyllosilicates are characterized as forming and remaining stable under conditions of low to moderate pH, while Fe/Mg‐phyllosilicates are considered representative of only dilute and moderate to high pH conditions. However, we have observed Al‐ and Fe/Mg‐phyllosilicates in acid saline lake sediments in Western Australia. Phyllosilicate formation mechanisms in these lake systems include direct precipitation from lake waters, early diagenetic precipitation from shallow groundwaters, and deposition/alteration of detrital grains. X‐ray diffraction analysis of silt‐ and clay‐size sediments from two acid saline lakes in Western Australia indicates the presence of several complex mineral assemblages with extreme spatial heterogeneity that reflects the complex geochemistry of these lakes. These assemblages include unique combinations of authigenic and/or detrital phyllosilicates (e.g., kaolinite, smectite, and palygorskite‐sepiolite), sulfates (e.g., alunite, jarosite, and gypsum), Fe‐oxides (e.g., hematite and goethite), and other silicates (e.g., mullite and heulandite‐clinoptilolite). Observations of Fe/Mg‐phyllosilicates found in acid saline sediments in southern Western Australia suggest their degradation under conditions of low pH (2.5–5.4) is slowed by the high salinity (5–25%) of the lake and shallow groundwaters. The occurrence of both Al‐ and Fe/Mg‐phyllosilicates in these acid saline lake sediments suggests that environmental interpretations based on the occurrence of phyllosilicates require additional consideration of their spatial distribution and association with other minerals. Moreover, the similarity between the diverse mineral assemblages in these terrestrial acid saline systems and those on Mars indicates similar conditions may have existed on Mars.
Shopping for hydrologically representative connectivity metrics in a humid temperate forested catchment
Authors: Ali Geneviève A. , Roy André G.
Published: December 2010

In order for connectivity to serve as an effective diagnostic classification tool of hydrological behavior, it clearly matters (1) how it is measured and (2) whether the chosen measures are correlated not only to catchment‐scale antecedent moisture conditions but also to streamflow discharges. Previous studies have advocated that connectivity in shallow soil moisture patterns induces threshold‐like changes in runoff in temperate rangeland catchments but not in temperate humid forested catchments. We argue that in the latter environments, capturing critical spatial organization in soil moisture patterns depends on the way the chosen connectivity metric is built. We therefore tested a large selection of 2‐D and 3‐D connectivity measures in a temperate humid forested catchment (Laurentians, Canada). Computations were based on continuous soil moisture patterns collected on 16 occasions at four soil depths and then transformed into indicator patterns using either time‐variable or time‐invariant thresholds. Assessments of connectivity were variable depending on the computed metric, as just a few measures were significantly correlated with both antecedent moisture conditions and catchment discharges. In particular, topography‐based connectivity metrics reflected changes in catchment macrostate and stormflow response better than omnidirectional methods. Also, source‐to‐stream connectivity metrics were more hydrologically sensitive than metrics that did not consider the spatial linkage to the stream channel. These conclusions stress the importance of searching for the right connectivity metric for hydrologic prediction, especially in humid forested environments that exhibit much larger variability in soil hydrologic properties than temperate rangeland catchments.
Overt fatal and chronic subclinical Encephalitozoon cuniculi microsporidiosis in a colony of captive emperor tamarins (Saguinus imperator)
Authors: Guscetti F. , Mathis A. , Hatt J.‐M. , Deplazes P.
Published: December 2010

Abstract: The course of an infection with the microsporidian Encephalitozoon cuniculi in a colony of captive emperor tamarins (Saguinus imperator) is described. In two litters, the infection was associated with overt disease and death of all infants. Immunohistochemistry for E. cuniculi showed generalized infections, and histopathologic evaluation revealed systemic vasculitis and disseminated mixed inflammatory cell infiltration with and without necrosis in several organs. Serologically, some of the juvenile animals presented with high titres for Encephalitozoon, while the adults had low titres. The E. cuniculi‘dog strain’ was identified by molecular means for the first time in Europe. The origin of the infection appeared to be a pair of breeding adults that originated from the US. Our data suggest that the organism persisted over years in the colony, and that subclinically infected animals most likely were involved in perpetuating the infection. Efforts should be made to ascertain if this microorganism is present in other captive populations of this endangered monkey species and to prevent its further spreading.
Instantaneous Capture and Mineralization of Flue Gas Carbon Dioxide: Pilot Scale Study
Authors: Reddy KJ , Weber Hollis , Bhattacharyya Pradip , Morris Argyle , Taylor David , Christensen Mikol , Foulke Thomas , Fahlsing Paul
Published: December 2010

Multiple CO2 capture and storage (CCS) processes are required to address anthropogenic CO2 problems. However, a method which can directly capture and mineralize CO2 at a point source, under actual field conditions, has advantages and could help offset the cost associated with the conventional CCS technologies. The mineral carbonation (MC), a process of converting CO2 into stable minerals (mineralization), has been studied extensively to store CO2. However, most of the MC studies have been largely investigated at laboratory scale. Objectives of this research were to develop a pilot scale AMC (accelerated mineral carbonation) process and test the effects of flue gas moisture content on carbonation of fly ash particles. A pilot scale AMC process consisting of a moisture reducing drum (MRD), a heater/humidifier, and a fluidized-bed reactor (FBR) was developed and tested by reacting flue gas with fly ash particles at one of the largest coal-fired power plants (2120 MW) in the USA. The experiments were conducted over a period of 2 hr at ~ 300 SCFM flow-rates, at a controlled pressure (115.1 kPa), and under different flue gas moisture contents (2-16%). The flue gas CO2 and SO2 concentrations were monitored before and during the experiments by an industrial grade gas analyzer. Fly ash samples were collected from the reactor sample port from 0-120 minutes and analyzed for total inorganic carbon (C), sulfur (S), and mercury (Hg). From C, S, and Hg concentrations, %calcium carbonate (CaCO3), %sulfate (SO42-), and %mercury carbonate (HgCO3) were calculated, respectively. Results suggested significant mineralization of flue gas CO2, SO2, and Hg within 10-15 minutes of reaction. Among different moisture conditions, ~16% showed highest conversion of flue gas CO2 and SO2 to %CaCO3 and %SO42- in fly ash samples. For example, an increase of almost 4% in CaCO3 content of fly ash was observed. Overall, the AMC process is cost-effective with minimum carbon footprint and can be retrofitted to coal fired power plants (existing and/or new) as a post-combustion unit to minimize flue gas CO2, SO2, and Hg emissions into the atmosphere. Used in conjunction with capture and geologic sequestration, the AMC process has the potential to reduce overall cost associated with CO2 separation/compression/transportation/pore space/brine water treatment. It could also help protect sensitive amines and carbon filters used in flue gas CO2 capture and separation process and extend their life.