bluuebunny/crossref_metadata_2025 huggingface dataset:
Regional neonatal brain absolute thermometry by 1H MRS
Authors: Bainbridge Alan , Kendall Giles S. , Vita Enrico De , Hagmann Cornelia , Kapetanakis Andrew , Cady Ernest B. , Robertson Nicola J.
Published: October 2012

Therapeutic hypothermia is standard care for infants with moderate to severe encephalopathy. 1H MRS thermometry (MRSt) measures regional brain absolute temperature using the temperature‐dependent water chemical shift. This study evaluates the clinical feasibility of MRSt in human neonates, and correlates white matter (WM) and thalamus (Thal) MRSt with conventional rectal temperature (Trectal) measurement. Fifty‐six infants born at term underwent perinatal MRSt for suspected hypoxic–ischaemic brain injury and 33 infants born preterm had MRSt at a term‐equivalent age; 56 of the 89 had Trectal measured after MRSt of either a Thal or posterior WM voxel, or both. MRSt used point‐resolved spectroscopy (no water suppression; TR = 1370 ms; TE = 288 ms; 1.5 × 1.5 × 1.5 cm3 Thal and 1.1 × 1.3 × 1.4 cm3 WM voxels). Time domain data were phase and frequency corrected before summation and motion‐corrupted data were excluded from further analysis using simple criteria [preprocessing + quality assurance (QA)]. Two published water temperature‐dependence calibrations [both using cerebral creatine (Cr), choline (Cho) and N‐acetylaspartate (Naa) as independent reference peaks] were compared. The temperature measurements derived from Cr, Cho and Naa were combined to give a single amplitude‐weighted combination temperature (TAWC). WM and Thal TAWC correlated linearly with Trectal (Thal slope, 0.82 ± 0.04, R2 = 0.85, p < 0.05; WM slope, 0.95 ± 0.04, R2 = 0.78, p < 0.05). Preprocessing + QA improved the correlation between WM TAWC and Trectal (R2 increased from 0.27 to 0.78, p < 0.001). Both calibration datasets showed specific inconsistencies between the temperatures calculated using Cr, Cho and Naa reference peaks when applied to this neonatal dataset. Neonatal MRSt is clinically feasible. Preprocessing + QA improved MRSt reliability in WM. The consideration of MRSt calibration internal biases is necessary before combining MRSt temperatures from multiple reference peaks to obtain TAWC. Copyright © 2012 John Wiley & Sons, Ltd.
Composite slice‐selective adiabatic excitation for prostate MRSI
Authors: Arteaga de Castro C. S. , Luttje M. P. , van Vulpen M. , Luijten P. R. , van der Heide U. A. , Klomp D. W. J.
Published: October 2012

Higher magnetic field strengths, such as 7 T, offer increased spectral resolution and higher signal‐to‐noise ratio. These properties can be very advantageous for MRSI. In particular, signals that generally overlap at lower fields, such as choline, polyamines and creatine, can be resolved at 7 T. However, higher magnetic field strengths suffer from strong radiofrequency (RF) field nonuniformities. These nonuniformities become even stronger when using surface transceivers, such as an endorectal coil for prostate imaging. In order to obtain uniform excitations for accurate MRSI measurements, adiabatic sequences are therefore recommended. Conventional adiabatic MRS sequences (i.e. localization by adiabatic selective refocusing, LASER) have relatively long TEs, especially when optimized to measure the strongly coupled spins of citrate in the prostate. The semi‐LASER (sLASER) sequence has a significantly shorter TE, although it does not provide adiabatic excitation. Therefore, we propose an adiabatic sLASER sequence that either has a composite adiabatic slice‐selective excitation (cLASER) or a non‐slice‐selective adiabatic excitation (nsLASER), allowing for shorter TEs, whilst maintaining the adiabatic spin excitation. Furthermore, the spatial properties of the composite adiabatic excitation allow for a high slice excitation bandwidth, resulting in negligible chemical shift displacement artifacts. Exclusion of the slice selection can be considered once the field of view extends beyond the transmit field of the RF coil. The use of a transceiver at high magnetic field strengths has shown that the cLASER and nsLASER sequences are suitable for MRSI of the prostate in both phantom andin vivovalidations. Copyright © 2012 John Wiley & Sons, Ltd.
Pterodon pubescens Oil: Characterisation, Certification of Origin and Quality Control via Mass Spectrometry Fingerprinting Analysis
Authors: Cabral E. C. , Sevart L. , Spindola H. M. , Coelho M. B. , Sousa I. M. O. , Queiroz N. C. A. , Foglio M. A. , Eberlin M. N. , Riveros J. M.
Published: October 2012

Introduction

The oil obtained from Pterodon pubescens (Leguminosae) seeds are known to display anti‐cancer, anti‐dermatogenic and anti‐nociceptive activitiy. Phytochemical studies have demonstrated that its main constituents are diterpenoids with voucapan skeletons. Considering the potential biological activities of the oil, rapid and efficient methods for assessing its quality would facilitate certification and quality control.

Objective

To develop a direct mass spectrometric fingerprinting method for the P. pubescens seed oil that would focus on the major diterpenoids constituents, enabling quality control, origin certification and recognition of marker species in commercially available products.

Method

Two techniques were used: (i) direct infusion electrospray ionisation (ESI) mass spectrometry after solvent extraction and dilution and (ii) ambient desorption/ionisation via easy ambient sonic‐spray ionisation, EASI(+)–MS, performed directly on the seed surface or at a paper surface imprinted with the oil.

Results

From a combination of ESI–MS, HRESI–MS and ESI–MS/MS data, 12 diterpenes were characterised, and typical profiles were obtained for the oil extract or the crude oil via both ESI–MS and EASI–MS. These techniques require no or very simple sample preparation protocols and the whole analytical processes with spectra acquisition take just a few minutes.

Conclusion

Both techniques, but particularly EASI–MS, provide simple, fast and efficient MS fingerprinting methodologies to characterise the P. pubescens oil with typical (di)terpene profiles being applicable to quality control and certification of authenticity and origin. Copyright © 2012 John Wiley & Sons, Ltd.
Interaction and electronic structures of oxygen divacancy in HfO2
Authors: Zhang Wei , Hou Z. F.
Published: October 2012

We have studied the interaction between two neutral oxygen vacancies and the electronic structures of oxygen divacancy in the monoclinic phase of HfO2 by performing the first‐principles calculations. It is found that the vacancy–vacancy interaction depends not only on the distance but also on the coordination of the removed oxygen atoms. The oxygen divacancy is formed energetically by the removal of two fourfold coordinated oxygen atoms (O4) with a distance of about 2.73 Å. The interaction between two O4 vacancies is attractive, indicating that the O4 vacancies tend to form stable cluster in HfO2. The oxygen divacancy induces two in‐gap defect levels, which correspond to a bonding state and an anti‐bonding one. These results would provide insightful information to understand the formation of conductive filaments in HfO2‐based resistive random access memory devices.
Evaluating agarwood products for 2‐(2‐phenylethyl)chromones using direct analysis in real time time‐of‐flight mass spectrometry
Authors: Lancaster Cady , Espinoza Edgard
Published: October 2012

RATIONALE

Agarwood is the resinous material harvested from threatened Aquilaria species. We investigated how many protonated 2‐(2‐phenylethyl)chromone ions were sufficient to make an accurate identification of agarwood. Analysis of 125 reference samples was carried out by direct analysis in real time time‐of‐flight mass spectrometry (DART‐TOFMS). The identification criteria developed were applied to commercial samples.

METHODS

We developed a technique that uses DART‐TOFMS to detect 2‐(2‐phenylethyl)chromones. Additionally, we developed a set of criteria to infer the presence of Aquilaria in commercial samples of wood chips, sawdust, incense and liquids. Additionally, we examined other fragrant woods to determine if they contained a chemical profile that could be falsely identified as agarwood.

RESULTS

Analysis of reference and commercial samples (n = 151) established that DART‐TOFMS provides reproducible mass spectra that are useful for inferring the genus of suspected agarwood samples. We identified 17 ions which were useful for authenticating agarwood. Comparison of the number of chromone ions detected by direct analyses of dry wood chips versus eluent analysis of methanol‐extracted wood showed that results were similar. Lastly, analysis of 25 scented woods of other species did not give false positive results.

CONCLUSIONS

Reliable criteria for inferring agarwood include the presence of diagnostic ions, m/z 319.118 or 349.129, in addition to ten or more ions characteristic of 2‐(2‐phenylethyl)chromones. Wood anatomists challenged with difficult morphological identifications can use this tool to assist in their analyses. Published 2012. This article is a US Government work and is in the public domain in the USA.
High‐precision measurements of 17O/16O and 18O/16O ratios in CO2
Authors: Barkan Eugeni , Luz Boaz
Published: October 2012

RATIONALE

Measurements of δ17O and δ18O values of tropospheric CO2 are of great importance. However, to be useful, such measurements must be an order of magnitude more precise than in current published literature. With this purpose we developed a new method for high‐precision mass spectrometric measurements of 17O/16O and 18O/16O ratios in CO2, which is presented in this study.

METHODS

The method is based on isotopic exchange equilibration between H2O and CO2 in sealed glass ampoules followed by water fluorination to produce O2. Dual inlet isotope ratio mass spectrometric (IRMS) measurements of the δ17O and δ18O values of this O2 allow δ17O values of CO2 to be obtained with very high precision (0.01 to 0.03 ‰). This method requires about 70 µmol of CO2.

RESULTS

Measurements of standard CO2 gas and atmospheric CO2 yield reproducibility of 0.01 to 0.03 ‰ for both δ17O and δ18O values, and 5 per meg for 17Oexcess. Fractionation factors 17α and 18α were determined in the H2O–CO2 equilibrium at 25 °C as 1.021254 ± 0.00004 and 1.041036 ± 0.00008, respectively, and the ratio ln17α/ln18α as 0.5229 ± 0.0001.

CONCLUSIONS

The results demonstrate that the new method is the most accurate analytical procedure ever presented for measurements of 17Oexcess of CO2 gas. It is suitable for measurements of CO2 extracted from relatively small samples of air (~5 L), and is thus useful for monitoring the 17Oexcess of CO2 on a broad global scale. Copyright © 2012 John Wiley & Sons, Ltd.
Intersample ripple‐free multirate optimal controller design
Authors: Sideris Athanasios
Published: October 2012

A systematic approach for the design of multirate controllers resulting in closed loops free of intersample ripple is proposed. The approach is particularly suited for design frameworks such as optimal control for which previous proposed conditions to eliminate intersample ripple cannot be readily incorporated. It is based on transforming the control inputs in the lifted transfer matrix of the design plant in a manner that stabilizing controllers for the transformed plant are in one‐to‐one correspondence with stabilizing ripple‐free controllers for the original plant. Thus, no solutions are lost in the process of this transformation and a general stability result is obtained that can be also used in other multirate controller design methodologies to achieve ripple‐free response. The results do not require that the plant should be open‐loop stable and in particular can contain integrating instabilities. Copyright © 2012 John Wiley & Sons, Ltd.
POTENTIAL LARGE WOODY DEBRIS RECRUITMENT DUE TO LANDSLIDES, BANK EROSION AND FLOODS IN MOUNTAIN BASINS: A QUANTITATIVE ESTIMATION APPROACH
Authors: Ruiz‐Villanueva V. , Díez‐Herrero A. , Ballesteros J. A. , Bodoque J. M.
Published: October 2012

In‐depth knowledge of the fluvial corridor and surrounding slopes and forest vegetation is needed for a better understanding of wood recruitment or inputs to rivers. The information available in Central Spain on hydrogeomorphic processes and forest distribution enabled the evaluation of potential wood recruitment from three sources: landslides, bank erosion and fluvial transport during floods on a regional scale. The method presented here is based on a geographical information system (GIS) and on multi‐criteria and multi‐objective assessment using fuzzy logic principles. First, the areas potentially affected by landslides, bank erosion and floods were delineated, and a vegetation analysis was carried out to obtain the vegetation resistance and forest density. Several scenarios were proposed based on the process frequency and severity. Using this method, the volume of potentially available wood can be estimated for each scenario.

Fourteen river basins in populated areas were selected for further analyses and field survey. Observations of in‐stream storage of woody debris and tree disturbances were used to interpret the woody debris dynamics throughout the watershed and validate the obtained results.

This method offers a suitable approach to define a watershed's capacity to recruit wood material to streams by delineating the source areas and estimating the order of magnitude of the wood volume in each case. The results may be useful to characterize the dynamics of woody debris from the perspective of the potential hazard of its transport during floods, and they can also be used for forest and river management and restoration. Copyright © 2012 John Wiley & Sons, Ltd.
Pathway index models for construction of patient‐specific risk profiles
Authors: Eng Kevin H. , Wang Sijian , Bradley William H. , Rader Janet S. , Kendziorski Christina
Published: October 2012

Statistical methods for variable selection, prediction, and classification have proven extremely useful in moving personalized genomics medicine forward, in particular, leading to a number of genomic‐based assays now in clinical use for predicting cancer recurrence. Although invaluable in individual cases, the information provided by these assays is limited. Most often, a patient is classified into one of very few groups (e.g., recur or not), limiting the potential for truly personalized treatment. Furthermore, although these assays provide information on which individuals are at most risk (e.g., those for which recurrence is predicted), they provide no information on the aberrant biological pathways that give rise to the increased risk. We have developed an approach to address these limitations. The approach models a time‐to‐event outcome as a function of known biological pathways, identifies important genomic aberrations, and provides pathway‐based patient‐specific assessments of risk. As we demonstrate in a study of ovarian cancer from The Cancer Genome Atlas project, the patient‐specific risk profiles are powerful and efficient characterizations useful in addressing a number of questions related to identifying informative patient subtypes and predicting survival. Copyright © 2012 John Wiley & Sons, Ltd.
Efficient bias correction for magnetic resonance image denoising
Authors: Mukherjee Partha Sarathi , Qiu Peihua
Published: October 2012

Magnetic resonance imaging (MRI) is a popular radiology technique that is used for visualizing detailed internal structure of the body. Observed MRI images are generated by the inverse Fourier transformation from received frequency signals of a magnetic resonance scanner system. Previous research has demonstrated that random noise involved in the observed MRI images can be described adequately by the so‐called Rician noise model. Under that model, the observed image intensity at a given pixel is a nonlinear function of the true image intensity and of two independent zero‐mean random variables with the same normal distribution. Because of such a complicated noise structure in the observed MRI images, denoised images by conventional denoising methods are usually biased, and the bias could reduce image contrast and negatively affect subsequent image analysis. Therefore, it is important to address the bias issue properly. To this end, several bias‐correction procedures have been proposed in the literature. In this paper, we study the Rician noise model and the corresponding bias‐correction problem systematically and propose a new and more effective bias‐correction formula based on the regression analysis and Monte Carlo simulation. Numerical studies show that our proposed method works well in various applications. Copyright © 2012 John Wiley & Sons, Ltd.
Resolving Sub‐Molecular Binding and Electrical Switching Mechanisms of Single Proteins at Electroactive Conducting Polymers
Authors: Gelmi A. , Higgins M. J. , Wallace G. G.
Published: October 2012

Polymer‐based electrodes for interfacing biological tissues are becoming increasingly sophisticated. Their many functions place them at the cross‐roads of electromaterials, biomaterials, and drug‐delivery systems. For conducting polymers, the mechanism of conductivity requires doping with anionic molecules such as extracellular matrix molecules, a process that distinguishes them as biomaterials and provides a means to control interactions at the cellular–electrode interface. However, due to their complex structure, directly observing the selective binding of target molecules or proteins has so far eluded researchers. This situation is compounded by the polymer's ability to adopt different electronic states that alter the polymer–dopant interactions. Here, the ability to resolve sub‐molecular binding specificity between sulfate and carboxyl groups of dopants and heparin binding domains of human plasma fibronectin is demonstrated. The interaction exploits a form of biological ‘charge complementarity’ to enable specificity. When an electrical signal is applied to the polymer, the specific interaction is switched to a non‐specific, high‐affinity binding state that can be reversibly controlled using electrochemical processes. Both the specific and non‐specific interactions are integral for controlling protein conformation and dynamics. These details, which represent the first direct measurement of biomolecular recognition between a single protein and any type of organic conductor, give new molecular insight into controlling cellular interactions on these polymer surfaces.
Smart‐grid policies: an international review
Authors: Brown Marilyn A. , Zhou Shan
Published: October 2012

The electric power systems of many industrialized nations are challenged by the need to accommodate distributed renewable generation, increasing demands of a digital society, growing threats to infrastructure security, and concerns over global climate disruption. The ‘smart grid’—with a two‐way flow of electricity and information between utilities and consumers—can help address these challenges, but various financial, regulatory, and technical obstacles hinder its rapid deployment. An overview of experiences with smart‐grid policies in pioneering countries shows that many governments have designed interventions to overcome these barriers and to facilitate grid modernization. Smart‐grid policies include a new generation of regulations and finance models such as regulatory targets, requirements for data security and privacy, renewable energy credits, and various interconnection tariffs and utility subsidies.

This article is categorized under:

Energy Infrastructure > Economics and Policy

Energy Systems Economics > Economics and Policy

Energy and Climate > Economics and Policy
Persistent anti-brane singularities
Authors: Bena Iosif , Junghans Daniel , Kuperstein Stanislav , Van Riet Thomas , Wrase Timm , Zagermann Marco
Published: October 2012

Abstract

Anti-D-branes inserted in warped throat geometries (supported by fluxes that carry D-brane charges) develop unphysical singularities. It has been argued that these singularities could be resolved when one goes beyond the linearized approximation or includes the effects of brane polarization. In this paper we consider anti-D6 branes, whose singularities have been shown to exist at the full non-linear level, and demonstrate that there is no D8 brane polarization that can resolve the singularity. We comment on the potential implications of this result for the resolution of anti-D3 brane singularities in the Klebanov-Strassler geometry.
Gaugino production in proton-proton collisions at a center-of-mass energy of 8 TeV
Authors: Fuks Benjamin , Klasen Michael , Lamprea David R. , Rothering Marcel
Published: October 2012

Abstract

Motivated by hints for a light Standard Model-like Higgs boson and a shift in experimental attention towards electroweak supersymmetry particle production at the CERN LHC, we update in this paper our precision predictions at next-to-leading order of perturbative QCD matched to resummation at the next-to-leading logarithmic accuracy for direct gaugino pair production in proton-proton collisions with a center-of-mass energy of 8 TeV. Tables of total cross sections are presented together with the corresponding scale and parton density uncertainties for benchmark points adopted recently by the experimental collaborations, and figures are presented for up-to-date model lines attached to them. Since the experimental analyses are currently obtained with parton showers matched to multi-parton matrix elements, we also analyze the precision of this procedure by comparing invariant-mass and transverse-momentum distributions obtained in this way to those obtained with threshold and transverse-momentum resummation.
Variations on Slavnov’s scalar product
Authors: Foda O. , Wheeler M.
Published: October 2012

Abstract

We consider the rational six-vertex model on anL×Llattice with domain wall boundary conditions and restrictNparallel-line rapidities,N≤L/2, to satisfy length-LXXX$ \mathrm{spin}-\frac{1}{2} $chain Bethe equations. We show that the partition function is an (L− 2N)- parameter extension of Slavnov’s scalar product of a Bethe eigenstate and a generic state, withNmagnons each, on a length-LXXX$ \mathrm{spin}-\frac{1}{2} $chain. Decoupling the extra parameters, we obtain a third determinant expression for the scalar product, where the first is due to Slavnov [1], and the second is due to Kostov and Matsuo [2]. We show that the new determinant is Casoratian, and consequently that tree-level$ \mathcal{N}=4 $SYM structure constants that are known to be determinants, remain determinants at 1-loop level.
Discovery of invariants through automated theory formation
Authors: Llano Maria Teresa , Ireland Andrew , Pease Alison
Published: October 2012

Refinement is a powerful mechanism for mastering the complexities that arise when formally modelling systems. Refinement also brings with it additional proof obligations—requiring a developer to discover properties relating to their design decisions. With the goal of reducing this burden, we have investigated how a general purpose automated theory formation tool, HR, can be used to automate the discovery of such properties within the context of the Event-B formal modelling framework. This gave rise to an integrated approach to automated invariant discovery. In addition to formal modelling and automated theory formation, our approach relies upon the simulation of system models as a key input to the invariant discovery process. Moreover we have developed a set of heuristics which, when coupled with automated proof-failure analysis, have enabled us to effectively tailor HR to the needs of Event-B developments. Drawing in part upon case study material from the literature, we have achieved some promising experimental results. While our focus has been on Event-B, we believe that our approach could be applied more widely to formal modelling frameworks which support simulation.
A critical discussion of the physics of wood–water interactions
Authors: Engelund Emil Tang , Thygesen Lisbeth Garbrecht , Svensson Staffan , Hill Callum A. S.
Published: October 2012

This paper reviews recent findings on wood–water interaction and puts them into context of established knowledge in the field. Several new findings challenge prevalent theories and are critically discussed in an attempt to advance current knowledge and highlight gaps. The focus of this review is put on water in the broadest concept of wood products, that is, the living tree is not considered. Moreover, the review covers the basic wood–water relation, states and transitions. Secondary effects such as the ability of water to alter physical properties of wood are only discussed in cases where there is an influence on state and/or transition.
Thoracic Duct Injury Following Esophagectomy in Carcinoma of the Esophagus: Ligation by the Abdominal Approach
Authors: Mishra Pramod Kumar , Saluja Sundeep Singh , Ramaswamy Dinesh , Bains Satinderpal Singh , Haque Parvez David
Published: October 2012

Background

Thoracic duct injury (TDI) is a potentially lethal complication of esophagectomy. There is no consensus regarding when and how to intervene in these injuries. Both thoracic and abdominal approaches have been used.

Methods

Esophagectomies performed for cancer of the esophagus (n = 104) from October 2003 to July 2011 were analyzed for TDI. Diagnosis, histological type, stage, and location of tumor, neoadjuvant therapy, trans‐thoracic or trans‐hiatal procedure performed, nature and amount of drain output, and levels of triglyceride in the effluent were analyzed. Management of these injuries and morbidity and mortality associated with the approach taken were reviewed.

Results

We observed chylothorax in 9 patients. All nine patients had undergone trans‐hiatal esophagectomy. All patients eventually required surgical intervention. Mass ligation of the thoracic duct was performed via the thoracic route in three patients and via the trans‐abdominal approach in six others. Thoracic duct ligation was successful in all patients. One patient required a second laparotomy and repeat ligation of the duct. There were two postoperative deaths; both these patients had ligation by the thoracic route.

Conclusions

Trans‐abdominal ligation of the thoracic duct in patients with chylothorax after esophagectomy is technically easy and safe. It may be preferred over the trans‐thoracic approach, especially after an initial trans‐hiatal esophagectomy.
Glutathione S‐Transferase M1 Gene Polymorphism Is Associated with Susceptibility to Impaired Long‐term Allograft Outcomes in Renal Transplant Recipients
Authors: Chang Horng‐Rong , Tsai Jen‐Pi , Yang Shun‐Fa , Lin Chih‐Kuang , Lian Jong‐Da
Published: October 2012

Background

Despite improved post‐transplantation care, progress in long‐term kidney allograft survival of diabetic renal transplant recipients (pre‐DM RTR) is worse than that of non‐diabetic recipients (non‐DM). We hypothesized that there are other potential risk factors, that predispose RTR to adverse renal allograft outcomes.

Methods

A total of 323 transplant recipients who underwent renal transplantation between March 2000 and January 2008 were recruited. The composite end‐point consisted of serum creatinine (SCr) doubling, graft failure, and death. Baseline clinical data were recorded, and polymerase chain reaction‐restriction fragment length polymorphism measurements of interleukin (IL)‐4, IL‐10, IL‐23, glutathione S‐transferase (GST)A1, GSTM1, and GSTP1 polymorphisms were determined. The risk factors for developing the primary outcome were analyzed among these clinical and genetic factors.

Results

Within a mean follow‐up of 71.1 ± 24 months, there were 43 (13.3 %) patients with the primary outcome. Stepwise multivariate Cox regression analysis was used to determine the risk factors for the primary outcome of RTR. Renal transplant recipients who possessed the GSTM1 null genotype had a 2.2‐fold risk (95 % CI: 1.10–4.40; P = 0.026) of developing the primary outcome. Additionally, RTR that had DM before transplantation (aHR: 3.31; 95 % CI: 1.77–6.20; P = 0.0002) or changes in SCr 6 to 12 months after transplantation (aHR: 2.83; 95 % CI: 1.29–6.19; P = 0.0095) had an increased risk of developing the primary outcome.

Conclusions

In addition to the adverse role played by DM, the GSTM1 null genotype also has an unfavorable influence on the long‐term allograft outcome of RTR.
Analysis of gamete membrane dynamics during double fertilization of Arabidopsis
Authors: Igawa Tomoko , Yanagawa Yuki , Miyagishima Shin-ya , Mori Toshiyuki
Published: October 2012

Angiosperms have a unique sexual reproduction system called “double fertilization.” One sperm cell fertilizes the egg and another sperm cell fertilizes the central cell. To date, plant gamete membrane dynamics during fertilization has been poorly understood. To analyze this unrevealed gamete subcellular behavior, live cell imaging analyses of Arabidopsis double fertilization were performed. We produced female gamete membrane marker lines in which fluorescent proteins conjugated with PIP2a finely visualized egg cell and central cell surfaces. Using those lines together with a sperm cell membrane marker line expressing GCS1-GFP, the double fertilization process was observed. As a result, after gamete fusion, putative sperm plasma membrane GFP signals were occasionally detected on the egg cell surface adjacent to the central cell. In addition, time-lapse imaging revealed that GCS1-GFP signals entered both the egg cell and the central cell in parallel with the sperm cell movement toward the female gametes during double fertilization. These findings suggested that the gamete fusion process based on membrane dynamics was composed of (1) plasma membrane fusion on male and female gamete surfaces, (2) entry of sperm internal membrane components into the female gametes, and (3) plasmogamy.
Polydactyly in the Southwest: Art or Anatomy—A Photo Essay
Authors: Hirthler Maureen A. , Hutchison Richard L.
Published: October 2012

Rock art in the Four Corners area often includes pictures of hands and feet, which may be representational or symbolic. There is correlation between actual metatarsal bones and carvings of polydactyl feet. No duplicated hand bones have been found, but we postulate petroglyphs of polydactyl hands are a reflection of a real congenital difference.
Evolution and the Cumulative Nature of Science
Authors: Zeigler David
Published: October 2012

One of the characteristics of science is its cumulative nature. As more discoveries are made and more is learned, we progressively come to a more and more complete understanding of the physical universe. Evolutionary biology serves as an excellent example of this progressive trend in knowledge, since we now understand significantly more about the mechanisms and details of the evolutionary process than we did in decades past. It is important to comprehend these progressive changes and communicate them effectively to students of evolutionary biology.
Teaching Tree Thinking to College Students: It’s Not as Easy as You Think
Authors: Phillips Brenda C. , Novick Laura R. , Catley Kefyn M. , Funk Daniel J.
Published: October 2012

The ability to understand and reason with tree-of-life diagrams (i.e., cladograms), referred to as tree thinking, is an essential skill for biology students. Yet, recent findings indicate that cladograms are cognitively opaque to many college students, leading them to misinterpret the information depicted. The current studies address the impact of prior biological background and instruction in phylogenetics on students’ competence at two foundational tree-thinking skills. In Study 1, college students with stronger (N = 52) and weaker (N = 60) backgrounds in biology were asked to (a) identify all the nested clades in two cladograms and (b) evaluate evolutionary relatedness among taxa positioned at different hierarchical levels (two questions) and included in a polytomy (two questions). Stronger-background students were more successful than weaker-background students. In Study 2, a subset of the stronger-background students (N = 41) who were enrolled in an evolution class subsequently received two days of instruction on phylogenetics. As expected, these students’ tree-thinking skills generally improved with instruction. However, although these students did very well at marking the nested clades, fundamental misinterpretations of relative evolutionary relatedness remained. The latter was especially, although not exclusively, the case for taxa included in a polytomy. These results highlight the importance of teaching cladistics, as well as the need to tailor such instruction to the difficulties students have learning key macroevolutionary concepts.
Introduction to Articles on Black Women and Work: Review of Black Political Economy Special Issue
Authors: Holder Michelle
Published: October 2012

Black women are one of the hardest working groups in the country. However, hard work is not always properly rewarded. The existence of wage inequities based on race has been shown to exist (Darity The Journal of Human Resources XVII: 72-91 1982), and black women have not been exempt from its implications. In addition, African American women still experience higher unemployment levels than their white female counterparts. In papers examining black women in the nursing profession, their income and earnings volatility, and inequities in their employment, Richard McGregory, Bradley Hardy, and Linda Loubert provide an overview of where black women stand in the U.S. labor market with respect to work and earnings. While these pieces show that African American women have made significant inroads into the American labor market there is still further to go.
Zuruf: Landschaft aus ökonomischer Sicht
Authors: Zimmermann Horst
Published: October 2012

This paper is a response to the special issue on the social constitution of cultural landscapes in “Raumforschung und Raumordnung”. It adopts an economic perspective that provides a sober-minded look at the issue of cultural landscape and reveals the economic significance of landscape. According to this perspective, (cultural) landscapes are characterised by features which are typical of public, regional, and scarce goods. From this it is argued that scarcity necessitates political intervention to ensure maximum benefits of use for the electorate.
Causal Effects of Single-Sex Schools on College Entrance Exams and College Attendance: Random Assignment in Seoul High Schools
Authors: Park Hyunjoon , Behrman Jere R. , Choi Jaesung
Published: October 2012

Despite the voluminous literature on the potentials of single-sex schools, there is no consensus on the effects of single-sex schools because of student selection of school types. We exploit a unique feature of schooling in Seoul—the random assignment of students into single-sex versus coeducational high schools—to assess causal effects of single-sex schools on college entrance exam scores and college attendance. Our validation of the random assignment shows comparable socioeconomic backgrounds and prior academic achievement of students attending single-sex schools and coeducational schools, which increases the credibility of our causal estimates of single-sex school effects. The three-level hierarchical model shows that attending all-boys schools or all-girls schools, rather than coeducational schools, is significantly associated with higher average scores on Korean and English test scores. Applying the school district fixed-effects models, we find that single-sex schools produce a higher percentage of graduates who attended four-year colleges and a lower percentage of graduates who attended two-year junior colleges than do coeducational schools. The positive effects of single-sex schools remain substantial, even after we take into account various school-level variables, such as teacher quality, the student-teacher ratio, the proportion of students receiving lunch support, and whether the schools are public or private.
Gender and the Neighborhood Location of Mixed-Race Couples
Authors: Wright Richard , Holloway Steven , Ellis Mark
Published: October 2012

Gender asymmetry in mixed-race heterosexual partnerships and marriages is common. For instance, black men marry or partner with white women at a far higher rate than white men marry or partner with black women. This article asks if such gender asymmetries relate to the racial character of the neighborhoods in which households headed by mixed-race couples live. Gendered power imbalances within households generally play into decisions about where to live or where to move (i.e., men typically benefit more than women), and we find the same in mixed-race couple arrangements and residential attainment. Gender interacts with race to produce a measurable race-by-gender effect. Specifically, we report a positive relationship between the percentage white in a neighborhood and the presence of households headed by mixed-race couples with a white male partner. The opposite holds for households headed by white-blacks and white-Latinos if the female partner is white; they are drawn to predominantly nonwhite neighborhoods. The results have implications for investigations of residential location attainment, neighborhood segregation analysis, and mixed-race studies.
A Sibling Death in the Family: Common and Consequential
Authors: Fletcher Jason , Mailick Marsha , Song Jieun , Wolfe Barbara
Published: October 2012

Although a large literature analyzes the determinants of child mortality and suggests policy and medical interventions aimed at its reduction, there is little existing analysis illuminating the consequences of child mortality for other family members. In particular, there is little evidence exploring the consequences of experiencing the death of a sibling on one’s own development and transition to adulthood. This article examines the prevalence and consequences of experiencing a sibling death during one’s childhood using two U.S. data sets. We show that even in a rich developed country, these experiences are quite common, affecting between 5 % and 8 % of the children with one or more siblings in our two data sets. We then show that these experiences are associated with important reductions in years of schooling as well as a broad range of adult socioeconomic outcomes. Our findings also suggest that sisters are far more affected than brothers and that the cause of death is an important factor in sibling effects. Overall, our findings point to important previously unexamined consequences of child mortality, adding to the societal costs associated with childhood mortality as well as suggesting additional benefits from policy and medical innovations aimed at curbing both such deaths and subsequent effects on family members.
Selective versus comparative processing
Authors: Kardes Frank R.
Published: October 2012

Simonson et al. (forthcoming) propose a new theory of comparison selection that explains which particular alternatives will be considered in a wide variety of judgment and choice tasks. Comparison selection depends on the latitude of acceptance, comparison fluency, and the interaction between these factors. Importantly, these factors integrate a wide variety of seemingly unrelated variables, and the theory is useful for generating novel hypotheses. However, because comparative processing occurs relatively infrequently, it is important to take a step back and specify the conditions under which comparative processing is likely to occur. Comparative processing is likely only when the motivation and the opportunity to process information carefully are high, when consumers lack knowledge about distributional standards, or when stimulus‐based judgment is likely. The two types of processes have different antecedents, consequences, and implications for debiasing.
Directions for judgment and decision making research based on comparison selection: Reply to Arkes, Johnson, and Kardes
Authors: Simonson Itamar , Bettman James R. , Kramer Thomas , Payne John W.
Published: October 2012

Our target article proposed an alternative perspective for studying consumer judgment and decision making, focusing on the types and weights of comparisons consumers select. In this response we consider the major points made by each of the commentators and examine their implications for future work addressing our comparison‐focused approach.
Aggregate Idiosyncratic Volatility
Authors: Bekaert Geert , Hodrick Robert J. , Zhang Xiaoyan
Published: October 2012

We examine aggregate idiosyncratic volatility in 23 developed equity markets, measured using various methodologies. We find no evidence of upward trends after extending the sample to 2008. Instead, idiosyncratic volatility is well described by a stationary autoregressive process that occasionally switches into a higher-variance regime that has relatively short duration. We also document that idiosyncratic volatility is highly correlated across countries. Most of the time variation in idiosyncratic volatility can be attributed to variation in a growth opportunity proxy, total (U.S.) market volatility, and in most specifications, the variance premium, a business cycle sensitive risk indicator.
Lymnaea neotropica and Lymnaea viatrix, potential intermediate hosts for Fascioloides magna
Authors: Sanabria R. , Mouzet R. , Pankrác J. , Djuikwo Teukeng F.F. , Courtioux B. , Novobilský A. , Höglund J. , Kašný M. , Vignoles P. , Dreyfuss G. , Rondelaud D. , Romero J.
Published: October 2012

Experimental infections of two South American lymnaeid populations with Fascioloides magna were carried out to determine whether these snails may sustain larval development of this digenean and, if so, to quantify their potential for cercarial production. The reference group was a French population of Galba truncatula infected and raised according to the same protocol. According to the internal transcribed sequence (ITS)-1 segment of their genomic rDNA, these South American populations were identified as Lymnaea neotropica (origin, Argentina) and Lymnaea viatrix var. ventricosa (origin, Uruguay). In the snail groups followed for cercarial shedding, longer prepatent periods and lower numbers of shed cercariae were noted in South American lymnaeids. In other snails dissected at day 65 post-exposure, the redial and cercarial burdens of F. magna found in the bodies of L. neotropica and L. v. ventricosa were significantly lower than those noted in G. truncatula. Compared to the total cercarial production noted in the dissected snails, the percentage of cercariae that exited from snails was 51.3% for G. truncatula, 32.2% for L. neotropica and 46.8% for L. v. ventricosa. The two South American species of snails can thus be considered as potential intermediate hosts of F. magna.
Ultrastructure of the cercomer of the metacestodeMicrosomacanthus paraparvulaRegel, 1994 (Cestoda: Hymenolepididae)
Authors: Pospekhova N.A. , Regel K.V.
Published: October 2012

Investigations were undertaken using light and transmission electron microscopy to clearly delineate the morphology of the cercomer, i.e. the protective envelopes and tail appendage, in cysticercoids ofMicrosomacanthus paraparvula, which develop in the haemocoel of the caddiswormGrensia praeterita(Insecta: Trichoptera). Two protective envelopes, the exocyst and endocyst, were identified. The non-cellular exocyst is found to consist of granular material and of thin, dense membrane-like layers, which are located parallel to each other. The exocyst of the mature metacestode tightly adjoins the outer surface of the endocyst, containing prospective parts (the scolex and the neck), except for the areas at its poles. A long tail appendage is located outside the exocyst. Evidence was found to indicate the existence of active synthetic processes occurring in the tail appendage. Non-cellular exocysts are widely distributed within metacestodes of the families Hymenolepididae and Dilepididae, and, presumably, are formed by means of glandular secretions from the oncosphere, given the early appearance of non-cellular exocysts in ontogeny.
Co-infections of the cestode Echinococcus vogeli and the nematode Calodium hepaticum in the hystricomorphic rodent Agouti paca from a forest reserve in Acre, Brazil
Authors: Almeida F. , Caldas R. , Corrêa C. , Rodrigues-Silva R. , Siqueira N. , Machado-Silva J.R.
Published: October 2012

The helminth fauna of Agouti paca (Linnaeus, 1766) has seldom been studied. In this paper, we report an unusual mixed infection of Echinococcus vogeli Rausch & Bernstein, 1972 and Calodium hepaticum (syn. Capillaria hepatica Bancroft, 1863) in free-ranging paca from a forested region in Acre (Brazil). Gross morphological examination revealed that paca liver contained multiple spherical to subspherical white or translucent lesions, which were isolated or frequently contiguous and partially covered by Glisson's capsule. Microscopic examination revealed unilocular cystic structures that contained abundant brood capsules in which numerous protoscolices budded from the inner surface. The protoscolices possessed rostellar hooks (33–41 μm in length), a morphological characteristic of the blade and calcareous corpuscles that is consistent with the metacestode E. vogeli. The diagnosis of C. hepaticum infection was based on the morphology and morphometry of the egg-shaped ellipsoids with bipolar plugs (44.8 ± 1.9 μm (length) × 24.4 ± 2.0 μm (width)) and liver histopathology. This finding expands the known range of C. hepaticum hosts in South America and, to the best of our knowledge, it is the first case of a mixed infection of E. vogeli and C. hepaticum. Furthermore, our data provide evidence that wild animal meat may be a source of C. hepaticum infection.
How to construct a case of Alzheimer's disease in three languages: case-based reasoning in narrative gerontology
Authors: SCHRAUF ROBERT W. , IRIS MADELYN , NAVARRO ELLEN , SMOTROVA TETYANA
Published: October 2012

This paper explores how people reason about Alzheimer's disease by telling stories about others who have the disease. More specifically, the paper is a cross-linguistic investigation of the narrative and linguistic devices used by African Americans in English, Mexican Americans in Spanish, and refugees/immigrants from the former Soviet Union (to the United States of America) in Russian in their oral productions of such stories. We examine the narratives as instances of case-based reasoning in which lay people (non-medical professionals) distinguish, represent and ‘perform’ symptomatic behaviours and construct a ‘case’ of the disease as a way of probing the difference between the normal and the pathological in conversational contexts. In particular, we examine situations in which stories are accepted and confirmed and situations in which stories are contested and negotiated. Common narrative and discursive devices across the three languages include concatenation, intertextuality, conjunction and conjunctive adverbs, lexical opposition, past progressive tenses, temporal adverbials, reported speech and prosodic cues. The fine-grained analysis of these narrative and discursive devices lays bare the inner-workings of case-based reasoning as a conversational task and suggests specific linguistic tools for intervening in lay narrative reasoning in clinical settings and in public health messaging about Alzheimer's disease.