bluuebunny/crossref_metadata_2025 huggingface dataset:
Integration of conflict into integrative taxonomy: fitting hybridization in species delimitation ofMesocarabus(Coleoptera:Carabidae)
Authors: Andújar C. , Arribas P. , Ruiz C. , Serrano J. , Gómez‐Zurita J.
Published: May 2014

In species differentiation, characters may not diverge synchronously, and there are also processes that shuffle character states in lineages descendant from a common ancestor. Species are thus expected to show some degree of incongruence among characters; therefore, taxonomic delimitation can benefit from integrative approaches and objective strategies that account for character conflict. We illustrate the potential of exploiting conflict for species delimitation in a study case of ground beetles of the subgenusCarabus(Mesocarabus), where traditional taxonomy does not accurately delimit species. The molecular phylogenies of four mitochondrial and three nuclear genes, cladistic analysis of the aedeagus, ecological niche divergence and morphometry of pronotal shape in more than 500 specimens ofMesocarabusshow that these characters are not fully congruent. For these data, a three‐step operational strategy is proposed for species delimitation by (i) delineating candidate species based on the integration of incongruence among conclusive lines of evidence, (ii) corroborating candidate species with inconclusive lines of evidence and (iii) refining a final species proposal based on an integrated characterization of candidate species based on the evolutionary analysis of incongruence. This procedure provided a general understanding of the reticulate process of hybridization and introgression acting onMesocarabusand generated the hypothesis of sevenMesocarabusspecies, including two putative hybrid lineages. Our work emphasizes the importance of incorporating critical analyses of character and phylogenetic conflict to infer both the evolutionary history and species boundaries through an integrative taxonomic approach.
Synthetic Population Generation with Multilevel Controls: A Fitness‐Based Synthesis Approach and Validations
Authors: Ma Lu , Srinivasan Sivaramakrishnan
Published: May 2014

The application of disaggregate models for predictions and policy evaluations requires as inputs detailed information on the socioeconomic characteristics of the population. The early procedure developed for population synthesis involved the generation of a joint multiway distribution of all attributes of interest using iterative proportional fitting (IPF). Recognizing its limitations, including the inability to deal with multilevel controls, several alternate methods have been proposed in the last few years. This article presents a methodology called the fitness‐based synthesis (FBS) that directly generates a list of households to match several multilevel controls without the need for determining a joint multiway distribution. The application and validation results demonstrate both the feasibility of the approach and its improved performance relative to the IPF and methods using fewer control tables. This article also presents a comprehensive validation of the synthetic populations against the true populations and thereby demonstrates the ability of the FBS method to generate the multidimensional correlations among the attributes. The number of iterations to terminations is found to be between one and three times the number of households to be synthesized. In sum, the FBS is an efficient and scalable methodology that is easy to implement and as such is a valuable tool for generating the detailed socioeconomic characteristics need for applying disaggregate travel‐demand forecasting models.
Toward a better understanding of gastrointestinal nitrergic neuromuscular transmission
Authors: Lies B. , Groneberg D. , Friebe A.
Published: May 2014

Background

Nitric oxide (NO) is an important inhibitory neurotransmitter in the gastrointestinal (GI) tract. The majority of nitrergic effects are transduced by NO‐sensitive guanylyl cyclase (NO‐GC) as the receptor for NO, and, thus, mediated by cGMP‐dependent mechanisms. Work carried out during the past years has demonstrated NO to be largely involved in GI smooth muscle relaxation and motility. However, detailed investigation of nitrergic signaling has turned out to be complicated as NO‐GC was identified in several different GI cell types such as smooth muscle cells, interstitial cells of Cajal and fibroblast‐like cells. With regards to nitrergic neurotransmission, special focus has been placed on the role of interstitial cells of Cajal using mutant mice with reduced populations of ICC. Recently, global and cell‐specific knockout mice for enzymes participating in nitrergic signaling have been generated providing a suitable approach to further examine the role of NO‐mediated signaling in GI smooth muscle.

Purpose

This review discusses the current knowledge on nitrergic mechanisms in gastrointestinal neuromuscular transmission with a focus on genetic models and outlines possible further investigations to gain better understanding on NO‐mediated effects in the GI tract.
PARTISAN GOVERNANCE AND POLICY IMPLEMENTATION: THE POLITICS OF ACADEMY CONVERSION AMONGST ENGLISH SCHOOLS
Authors: HICKS TIMOTHY
Published: May 2014

This article demonstrates that party‐political orientations within governance communities can have strong effects on policy implementation. Empirical evidence is drawn from the Academy conversion scheme for secondary schools in England that was recently pursued by the Conservative and Liberal Democrat coalition government. The opt‐in nature of the reform makes it possible to discern the impact that nominally apolitical school governors have on the implementation of the policy. Academy conversion is disproportionately found in more Conservative‐voting constituencies due to varying school‐level propensities to apply to convert, rather than varying propensities for the Department for Education to authorize conversions. Further, applications to convert are significantly more likely from schools in Conservative parliamentary seats that are under the control of Labour local authorities. Thus, nominally apolitical policy participants appear to act in rather political ways, which has implications for our understanding of the involvement of civil society in the provision of public services.
Patterns of increases in interleukin‐6 and C‐reactive protein as predictors for white matter injury in preterm infants
Authors: Inomata Kei , Mizobuchi Masami , Tanaka Satoshi , Iwatani Sota , Sakai Hitomi , Yoshimoto Seiji , Nakao Hideto
Published: May 2014

Background

The aim of this study was to determine whether patterns of increases in serum interleukin‐6 (IL‐6) and C‐reactive protein (CRP) levels at birth were associated with the development of white matter injury (WMI) in preterm infants with a fetal inflammatory response (FIR).

Methods

One hundred infants who were born at <32 weeks gestation and had funisitis, as determined by histological evidence of FIR, were studied. Infants were divided into four groups according to IL‐6 and CRP levels at birth, with cut‐off values of 200 pg/mL and 0.4 mg/dL, respectively. We compared the incidence of WMI, determined by MRI at term‐equivalent age, among these groups.

Results

The number of infants in each group was 12, 43, 0, and 45 in the high IL‐6 and high CRP (HH) group, high IL‐6 and low CRP (HL) group, low IL‐6 and high CRP (LH) group, and low IL‐6 and low CRP (LL) group, respectively. The incidence of WMI was significantly higher in the HH group than in the HL group and LL group (83%, 40%, and 34%, respectively). Multiple logistic regression analysis revealed that a combined elevation in IL‐6 and CRP levels was an independent predictor for the development of WMI (odds ratio, 8.3).

Conclusion

A combined elevation in serum IL‐6 and CRP levels at birth was associated with the development of WMI in preterm infants with FIR.
School Choice and Educational Stratification
Authors: Carlson Deven
Published: May 2014

Recent growth in the number of school choice programs across the country has ignited debate on the stratifying effects of these programs. In the context of interdistrict open enrollment, this paper analyzes—both theoretically and empirically—how choice programs affect stratification levels through the mechanisms of (i) the relative characteristics of program participants and nonparticipants and (ii) the schooling choices of different groups of program participants. The theoretical analysis uses Monte Carlo simulation techniques to analyze a hypothetical world where interdistrict choice is available to students in three school districts that are allowed to vary in student composition, the type of students who take advantage of the interdistrict choice program, and schooling choices of students who open enroll. The results of these simulations provide an understanding of the conditions under which an interdistrict open enrollment program leads to increases, decreases, or no changes in stratification levels. The empirical analysis uses data from the universe of students attending Colorado public schools in 2009–10 to examine how the state's interdistrict choice program affects stratification levels. It also analyzes the factors responsible for any increases or decreases in stratification and finds both participation patterns and differences in schooling decisions across groups to play important roles. The paper concludes with a discussion of its implications for research and policy.
Effect of Exercise Programs With Aerobic Exercise Sessions of Similar Intensity but Different Frequency and Duration on Health-Related Measures in Overweight Women
Authors: Manthou Eirini , Gill Jason M.R. , Malkova Dalia
Published: May 2014

Background:

This study investigated health-related effects of exercise programs with exercise sessions of similar intensity but different frequency and duration.

Methods:

Thirty-four overweight women were randomized into either long-bout (LB) or short-bout (SB) exercise groups. Participants performed an 8-week supervised program, with the LB group exercising for 75 minutes twice per week, and the SB group for 30 minutes on 5 days of the week.

Results:

The LB group completed 16 sessions at a heart rate (HR) of 127 ± 1 beat·min−1 and the SB group completed 40 sessions at a HR of 126 ± 1 beat·min−1. Weekly energy expenditure of exercise was not different between groups (LB group, 5.64 ± 0.34 MJ; SB group, 5.83 ± 0.23 MJ). Training significantly (P < .05) increased measures of cardiorespiratory fitness, decreased waist circumference, insulin resistance, and diastolic blood pressure. The group × time interaction was not significant for any of these factors, indicating that responses to exercise training did not differ between the SB and LB groups.

Conclusions:

Health-related outcomes of exercise programs with similar energy expenditure are independent of frequency and duration of exercise sessions. This provides individuals with a degree of flexibility in exercise program planning.
Determinants of Variance in the Habitual Physical Activity of Overweight Adults
Authors: Paul David R. , Kramer Matthew , Stote Kim S. , Baer David J.
Published: May 2014

Background:

The number of days of data and number of subjects necessary to estimate total physical activity (TPA) and moderate-to-vigorous physical activity (MVPA) requires an understanding of within- and between-subject variances, and the influence of sex, body composition, and age.

Methods:

Seventy-one adults wore accelerometers for 7-day intervals over 6 consecutive months.

Results:

Body fat and sex influenced TPA and MVPA. The sources of subject-related variation for TPA and MVPA were within-subject (48.4% and 54.3%), between-subject (34.3% and 31.8%), and calendar effects (17.3% and 13.9%). Based on within-subject variances, the error associated with estimating TPA and MVPA by collecting 1 to 7 days of data ranged from 28.2% to 13.3% for TPA and 62.0% to 28.6% for MVPA. Based on between-subject variances, detecting a 10% difference between 2 groups at a power of 90% requires approximately 200 and 725 subjects per group for TPA and MVPA, respectively.

Conclusions:

Estimates of MVPA are more variable than TPA in overweight adults, therefore more days of data are required to estimate MVPA and larger sample sizes to detect treatment differences for MVPA. Log-transforming data reduces the need for additional days of data collection, thereby improving chances of detecting treatment effects.
Lignin Valorization: Improving Lignin Processing in the Biorefinery
Authors: Ragauskas Arthur J. , Beckham Gregg T. , Biddy Mary J. , Chandra Richard , Chen Fang , Davis Mark F. , Davison Brian H. , Dixon Richard A. , Gilna Paul , Keller Martin , Langan Paul , Naskar Amit K. , Saddler Jack N. , Tschaplinski Timothy J. , Tuskan Gerald A. , Wyman Charles E.
Published: May 2014

Background

Lignin, nature’s dominant aromatic polymer, is found in most terrestrial plants in the approximate range of 15 to 40% dry weight and provides

structural integrity. Traditionally, most large-scale industrial processes that use plant polysaccharides have burned lignin to generate the power needed to productively transform biomass. The advent of biorefineries that convert cellulosic biomass into liquid transportation fuels will generate substantially more lignin than necessary to power the operation, and therefore efforts are underway to transform it to value-added products.

Advances

Bioengineering to modify lignin structure and/or incorporate atypical components has shown promise toward facilitating recovery and chemical transformation of lignin under biorefinery conditions. The flexibility in lignin monomer composition has proven useful for enhancing extraction efficiency. Both the mining of genetic variants in native populations of bioenergy crops and direct genetic manipulation of biosynthesis pathways have produced lignin feedstocks with unique properties for coproduct development. Advances in analytical chemistry and computational modeling detail the structure of the modified lignin and direct bioengineering strategies for targeted properties. Refinement of biomass pretreatment technologies has further facilitated lignin recovery and enables catalytic modifications for desired chemical and physical properties.

Outlook

Potential high-value products from isolated lignin include low-cost carbon fiber, engineering plastics and thermoplastic elastomers, polymeric foams and membranes, and a variety of fuels and chemicals all currently sourced from petroleum. These lignin coproducts must be low cost and perform as well as petroleum-derived counterparts. Each product stream has its own distinct challenges. Development of renewable lignin-based polymers requires improved processing technologies coupled to tailored bioenergy crops incorporating lignin with the desired chemical and physical properties. For fuels and chemicals, multiple strategies have emerged for lignin depolymerization and upgrading, including thermochemical treatments and homogeneous and heterogeneous catalysis. The multifunctional nature of lignin has historically yielded multiple product streams, which require extensive separation and purification procedures, but engineering plant feedstocks for greater structural homogeneity and tailored functionality reduces this challenge.
Imaging Crystallization
Authors: Dandekar Preshit , Doherty Michael F.
Published: May 2014

Real-time atomic force microscopy provides insights into complex processes associated with crystal growth.

[Also see Report by
Lupulescu and Rimer
]
Electronic Control of Circularly Polarized Light Emission
Authors: Zaumseil Jana
Published: May 2014

The handedness of circularly polarized light, which is normally controlled by rotating filters, was switched by the electric field direction in a light-emitting device.

[Also see Report by

Zhang
et al.

]
Think Outside the Lab
Authors: McNutt Marcia
Published: May 2014

Last month, the U.S. National Science Foundation (NSF) released a report
*
with some grim news that confirmed what is painfully obvious to recent Ph.D. graduates in science, technology, engineering, and mathematics (STEM) fields: Unemployment for this cohort is on the rise (at 2.4% in 2010, up nearly a percentage point since 2008). Although it remains below the U.S. national average for all workers (8.2%), for bright students who have invested many years in specialized education and training, the outlook is discouraging. Furthermore, according to an NSF survey, in 2008 only 16% of Ph.D.'s in science, engineering, and health fields held positions in academia within 3 years of earning a doctorate.
†
Prospects for employment can be improved, however, for STEM Ph.D.'s who make a concerted effort to learn about positions outside the lab and prepare themselves for alternative paths.
Crippling Virus Set to Conquer Western Hemisphere
Authors: Enserink Martin
Published: May 2014

Now that it has landed in the Caribbean, the chikungunya virus will spread widely in the Americas, scientists say.
Job Change Lands Egyptian Scientist in Legal Battle
Authors: Carpenter Jennifer
Published: May 2014

A lawsuit put forth by an Egyptian university claims that the resignation of one of its scientists damaged the institution's reputation and caused it to forfeit a grant.
Beyond the Temples
Authors: Wade Lizzie
Published: May 2014

Turning their backs on spectacular monuments, archaeologists are studying ordinary households to uncover the daily rhythms of long-lost cities.
Complete Genome Sequence of a Newcastle Disease Virus from a
Coturnix coturnix japonica
(Japanese Quail) Covey in India
Authors: Bhuvaneswari Srinivasan , Tirumurugaan Krishnaswamy Gopalan , Jones Jagaraj Cyril , Kumanan Kathaperumal
Published: May 2014

The genome of a Newcastle disease virus isolated from a Japanese quail in 2003 is reported here. The genome is 15,192 nucleotides (nt) long, as found in the recent genotypes, and grouped as genotype VIIb, with a 6-nt insertion. This is the first report on the sequence of a genotype VII Newcastle disease virus (NDV) from India.
Laboratory Evaluation of the BD MAX MRSA Assay
Authors: Widen Raymond , Healer Vicki , Silbert Suzane
Published: May 2014

A comparison between the BD MAX MRSA and Xpert MRSA assays was performed using 239 nares samples. A 97.9% overall agreement between the two molecular assays was observed. The BD MAX MRSA assay proved to be a reliable alternative for a highly automated system to detect methicillin-resistant
Staphylococcus aureus
(MRSA) in patient nares samples.
Extremes of Age Are Associated with Indeterminate QuantiFERON-TB Gold Assay Results
Authors: Tebruegge Marc , de Graaf Hans , Sukhtankar Priya , Elkington Paul , Marshall Ben , Schuster Helmut , Patel Sanjay , Faust Saul N.
Published: May 2014

Results from 3,263 QuantiFERON-TB Gold in-tube (QFT-GIT) assays were analyzed to determine the impact of age on test performance. The proportion of indeterminate results was significantly higher in pediatric and elderly (9.1% and 7.4%, respectively) than in adult (2.6%; chi-square test,
P
< 0.0001) patients. A detailed analysis of indeterminate QFT-GIT assay results is presented.
Adeno-Associated Virus Rep Represses the Human Integration Site Promoter by Two Pathways That Are Similar to Those Required for the Regulation of the Viral p5 Promoter
Authors: Dutheil Nathalie , Smith Sarah C. , Agúndez Leticia , Vincent-Mistiaen Zoé I. , Escalante Carlos R. , Linden R. Michael , Henckaerts Els
Published: May 2014

Adeno-associated virus serotype 2 (AAV2) can efficiently replicate in cells that have been infected with helper viruses, such as adenovirus or herpesvirus. However, in the absence of helper virus infection, AAV2 establishes latency by integrating its genome site specifically into
PPP1R12C
, a gene located on chromosome 19. This integration target site falls into one of the most gene-dense regions of the human genome, thus inviting the question as to whether the virus has evolved mechanisms to control this complex transcriptional environment in order to facilitate integration, maintain an apparently innocuous latency, and/or establish conditions that are conducive to the rescue of the integrated viral genome. The viral replication (Rep) proteins control and direct every known aspect of the viral life cycle and have been shown to tightly control all AAV2 promoters. In addition, a number of heterologous promoters are repressed by the AAV2 Rep proteins. Here, we demonstrate that Rep proteins efficiently repress expression from the target site
PPP1R12C
promoter. We find evidence that this repression employs mechanisms similar to those described for Rep-mediated AAV2 p5 promoter regulation. Furthermore, we show that the repression of the cellular target site promoter is based on two distinct mechanisms, one relying on the presence of a functional Rep binding motif within the 5′ untranslated region (UTR) of
PPP1R12C
, whereas the second pathway requires only an intact nucleoside triphosphate (NTP) binding site within the Rep proteins, indicating the possible reliance of this pathway on interactions of the Rep proteins with cellular proteins that mediate or regulate cellular transcription.

IMPORTANCE
The observation that repression of transcription from the adeno-associated virus serotype 2 (AAV2) p5 and integration target site promoters is mediated by shared mechanisms highlights the possible coevolution of virus and host and could lead to the identification of host factors that the virus exploits to navigate its life cycle.
Congenital hypothyroidism presenting as pseudo-obstruction in preterm infants
Authors: Sellappan B , Chakraborty M , Cherian S
Published: May 2014

Congenital hypothyroidism (CH) presenting as acute pseudo-obstruction is uncommon. We report two premature infants presenting with acute bowel obstruction subsequently diagnosed to have CH. Both responded well to medical management with thyroid supplementation.
Three-dimensional spectral domain optical coherence tomography in chronic exposure to welding arc
Authors: Saxena Sandeep , Mishra Nibha , Meyer Carsten H
Published: May 2014

Three-dimensional spectral domain optical coherence tomography was performed in a 26-year-old man with chronic exposure to welding arc. Advanced macular visualisation provided significant findings of inner segment-ellipsoid zone disruption with the presence of cystoid changes and hyper-reflective material in the area of disruption. The external limiting membrane was intact in both the eyes. C-scan retinal pigment epithelium fit map of the left eye revealed a well-delineated defect whereas the right eye showed a poorly delineated smaller defect. The hyper-reflective material can be hypothesised to originate from the disrupted photoreceptor layer. The hyper-reflective material was more evident in the left eye which could be correlated with more marked diminution of vision and a prominent yellow lesion at the fovea.
Towards global benchmarking of food environments and policies to reduce obesity and diet-related non-communicable diseases: design and methods for nation-wide surveys
Authors: Vandevijvere Stefanie , Swinburn Boyd ,   for the International Network for Food and Obesity/non-communicable diseases (NCDs) Research, Monitoring and Action Support (INFORMAS)
Published: May 2014

Introduction

Unhealthy diets are heavily driven by unhealthy food environments. The International Network for Food and Obesity/non-communicable diseases (NCDs) Research, Monitoring and Action Support (INFORMAS) has been established to reduce obesity, NCDs and their related inequalities globally. This paper describes the design and methods of the first-ever, comprehensive national survey on the healthiness of food environments and the public and private sector policies influencing them, as a first step towards global monitoring of food environments and policies.

Methods and analysis

A package of 11 substudies has been identified: (1) food composition, labelling and promotion on food packages; (2) food prices, shelf space and placement of foods in different outlets (mainly supermarkets); (3) food provision in schools/early childhood education (ECE) services and outdoor food promotion around schools/ECE services; (4) density of and proximity to food outlets in communities; food promotion to children via (5) television, (6) magazines, (7) sport club sponsorships, and (8) internet and social media; (9) analysis of the impact of trade and investment agreements on food environments; (10) government policies and actions; and (11) private sector actions and practices. For the substudies on food prices, provision, promotion and retail, ‘environmental equity’ indicators have been developed to check progress towards reducing diet-related health inequalities. Indicators for these modules will be assessed by tertiles of area deprivation index or school deciles. International ‘best practice benchmarks’ will be identified, against which to compare progress of countries on improving the healthiness of their food environments and policies.

Dissemination

This research is highly original due to the very ‘upstream’ approach being taken and its direct policy relevance. The detailed protocols will be offered to and adapted for countries of varying size and income in order to establish INFORMAS globally as a new monitoring initiative to reduce obesity and diet-related NCDs.
Palatability evaluation study of a new oral formulation of marbofloxacin in cats
Authors: Cron M. , Zemirline C. , Beranger J. , Privat V.
Published: May 2014

At a time when antimicrobial resistance is a global concern in human and animal health, it is of primary importance to draw attention to the problem of compliance with antibiotic therapy in animals hard to medicate such as cats. Resistance may develop because of poor patient compliance with the prescribed course of antibiotic therapy. Increasing palatability might enhance administration compliance. We assessed the acceptability of EFEX tablets, a new oral marbofloxacin formulation for cats. The objective of this study was to compare EFEX to two commercial formulations of marbofloxacin: MARBOCYL P palatable tablets and MARBOCYL Vet tablets. Acceptance tests were run in experimental conditions in 24 cats to compare the spontaneous intake and full consumption of the three pharmaceutical products. The results indicated that EFEX was more palatable than MARBOCYL Vet (0.001<P <0.01) and equally comparable with MARBOCYL P in palatability. There was no difference in the short‐term adverse effects between the products.
pH study of zinc oxide nanorods grown on indium tin oxide coated substrate,
Authors: Farmer Kevin , Hari Parameswar , Roberts Kenneth
Published: May 2014

Controlled growth of ZnO nanorods on various substrates is of great interest in photonic and electronic device applications. Also of interest is increasing the optical activity of zinc oxide nanorods in the visible spectrum. In this study, we report pH dependence for the morphology and photoluminescence of aligned ZnO nanorods grown on an indium tin oxide (ITO) coated glass substrate deposited by a wet chemical bath deposition method. The ZnO nanorods were grown by a chemical bath deposition technique using equimolar ratios of zinc (II) nitrate and hexamethylenetetramine in solution at 95 °C. The pH of the reaction solution prior to oven heating was varied from pH 5 to 10.6. Surface properties of the ZnO nanorods on ITO substrates were studied using scanning electron microscopy and photoluminescence spectroscopy. We also compared the use of NaOH to adjust the pH with the use of NH4OH, the latter necessary at higher pH due to the relative insolubility of zinc. It was found that the size of the nanorods can vary twofold with pH and the choice of base. Uniformity of coverage is also significantly dependent upon these variables and will be discussed as it relates to solubility and crystal growth. It was also found that the intensity of the photoluminescence in the visible range is pH dependent. For example, the intensity of luminescence at 550 nm for ZnO nanorods grown at pH 7 using NH4OH is 532% of the corresponding emission for a sample prepared at pH 5.
ULTRA-LOW-VOLTAGE GAIN-ENHANCED FOUR-PHASE CHARGE PUMP WITHOUT BODY EFFECT
Authors: LIN CHANGLONG , SUN XINZHUO , MA SHILIANG , LU XIN , LIANG KE , LI GUOFENG
Published: May 2014

In this paper, an ultra-low-voltage gain-enhanced four-phase charge pump is proposed. The proposed charge pump is designed in 0.18 μm 1.8 V standard CMOS process with high voltage boosting efficiency when the supply voltage is between 0.5 V and 1.8 V. Moreover, it eliminates the body effect by means of adding two auxiliary substrate switching PMOS transistor. The simulation results show that the proposed charge pump has higher efficiency than the other two low voltage charge pumps when the resistive load is 100 M ohm and the supply voltage is between 0.5 and 1.8 V. A test chip has been realized in a 0.18 μm 1.8 V standard CMOS process. The test results show perfect performance when the supply voltage is between 0.7 and 1.8 V. The proposed charge pump is quite suitable for low power applications.
IMPROVED SPECTRUM SEARCHING GENERALIZED–ESPRIT ALGORITHM FOR JOINT DOD AND DOA ESTIMATION IN MIMO RADAR WITH NON-UNIFORM LINEAR ARRAYS
Authors: CHEN WEIYANG , ZHANG XIAOFEI
Published: May 2014

This paper investigates the problem of angle estimation for bistatic multiple-input multiple-output (MIMO) radar with non-uniform linear arrays, and proposes an improved spectrum searching generalized estimation of signal parameters via rotational invariance techniques (ESPRIT) algorithm for joint direction of departure (DOD) and direction of arrival (DOA) estimation algorithm in bistatic MIMO radar. The proposed algorithm obtains initial estimation of angles obtained from the signal subspace, and uses the 1D local searchings to achieve the joint estimation of DOD and DOA. Compared to the spectrum searching generalized-ESPRIT algorithm which requires the global searchings and additional pairing, the proposed algorithm just needs the local searchings and obtains automatically paired 2D angle estimation. The angle estimation performance of the proposed algorithm is almost the same as that of the generalized-ESPRIT algorithm, and better than ESPRIT-like algorithm. Furthermore, the proposed algorithm is suitable for irregular array geometry, has much lower complexity than the spectrum searching generalized-ESPRIT algorithm, and imposes less constraint on the transmit/receive sensor spacing, which need not be limited to a half-wavelength strictly. The simulation results verify the effectiveness of the algorithm.
A MATHEMATICAL MODEL FOR THE TREATMENT OF AIDS-RELATED KAPOSI'S SARCOMA
Authors: SZOMOLAY BARBARA , LUNGU EDWARD M.
Published: May 2014

We formulate a mathematical model to study the dynamics of HIV-1 related Kaposi's Sarcoma (KS) pathogenesis. KS progression is modeled as a dual process involving the primary infection of B cells, which sustains HHV-8 replication and the secondary infection of progenitor cells by HHV-8, which sustains the KS cell replication. We incorporate the pharmacodynamics of highly active antiretroviral therapy (HAART), or combination therapy (HAART plus KS therapy) and consider how each treatment strategy alters the disease progression. Our results indicate that administration of HAART to individuals co-infected with the HIV-1 and HHV-8 viruses can greatly amplify the therapeutic response of low-dose KS therapies. We have found that adherence levels above 85% can significantly reduce the risk of KS and HIV for a treatment periods under 1 year. For longer treatment periods, however, at least 90% adherence level is recommended.
Modelling Polycrystalline Materials: An Overview of Three-Dimensional Grain-Scale Mechanical Models
Authors: Benedetti I. , Barbe F.
Published: May 2014

A survey of recent contributions on three-dimensional grain-scale mechanical modelling of polycrystalline materials is given in this work. The analysis of material micro-structures requires the generation of reliable micro-morphologies and affordable computational meshes as well as the description of the mechanical behavior of the elementary constituents and their interactions. The polycrystalline microstructure is characterized by the topology, morphology and crystallographic orientations of the individual grains and by the grain interfaces and microstructural defects, within the bulk grains and at the inter-granular interfaces. Their analysis has been until recently restricted to two-dimensional cases, due to high computational requirements. In the last decade, however, the wider affordability of increased computational capability has promoted the development of fully three-dimensional models. In this work, different aspects involved in the grain-scale analysis of polycrystalline materials are considered. Different techniques for generating artificial micro-structures, ranging from highly idealized to experimentally based high-fidelity representations, are briefly reviewed. Structured and unstructured meshes are discussed. The main strategies for constitutive modelling of individual bulk grains and inter-granular interfaces are introduced. Some attention has also been devoted to three-dimensional multiscale approaches and some established and emerging applications have been discussed.
Repeated injection of hydrothermal fluids into downdip carbonates: a diagenetic and stratigraphic mechanism for localization of reservoir porosity, Indian Basin Field, New Mexico, USA
Authors: Hiemstra Erik J. , Goldstein Robert H.
Published: May 2014

A detailed study of the Pennsylvanian Indian Basin Field of New Mexico, USA is used to develop a conceptual model that predicts reservoir porosity in clean down-depositional-dip marine carbonate, where repeated fracturing allows for hydrothermal fluid flow. Strata updip probably experienced repeated events of subaerial exposure, resulting in mineralogical stabilization and extensive calcite cementation that prevented extensive hydrothermal alteration. Clean, carbonate sediment deposited downdip was more prone to alteration by hydrothermal fluids. In the reservoir, cement stratigraphy shows regionally persistent zones closely associated with fracturing. Fluid inclusion data show high temperatures and repeated rises and falls, indicating tectonic valving in a hydrothermal system. Salinity data support this and indicate a late event of meteoric influx. Sr- and O-isotope data indicate higher temperature and less rock–water interaction in fault damage zones, evidence for intensified fluid flow in such areas. Formation of vugs and molds was associated with the hydrothermal fluid flow, which was driven by convection, probably initiated during 40–30 Ma intrusive activity and continuing after the onset of Basin and Range uplift and unroofing.
Sphingolipids affect fibrinogen-induced caveolar transcytosis and cerebrovascular permeability
Authors: Muradashvili Nino , Khundmiri Syed Jalal , Tyagi Reeta , Gartung Allison , Dean William L. , Lee Menq-Jer , Lominadze David
Published: May 2014

Inflammation-induced vascular endothelial dysfunction can allow plasma proteins to cross the vascular wall, causing edema. Proteins may traverse the vascular wall through two main pathways, the paracellular and transcellular transport pathways. Paracellular transport involves changes in endothelial cell junction proteins, while transcellular transport involves caveolar transcytosis. Since both processes are associated with filamentous actin formation, the two pathways are interconnected. Therefore, it is difficult to differentiate the prevailing role of one or the other pathway during various pathologies causing an increase in vascular permeability. Using a newly developed dual-tracer probing method, we differentiated transcellular from paracellular transport during hyperfibrinogenemia (HFg), an increase in fibrinogen (Fg) content. Roles of cholesterol and sphingolipids in formation of functional caveolae were assessed using a cholesterol chelator, methyl-β-cyclodextrin, and the de novo sphingolipid synthesis inhibitor myriocin. Fg-induced formation of functional caveolae was defined by association and colocalization of Na+-K+-ATPase and plasmalemmal vesicle-associated protein-1 with use of Förster resonance energy transfer and total internal reflection fluorescence microscopy, respectively. HFg increased permeability of the endothelial cell layer mainly through the transcellular pathway. While MβCD blocked Fg-increased transcellular and paracellular transport, myriocin affected only transcellular transport. Less pial venular leakage of albumin was observed in myriocin-treated HFg mice. HFg induced greater formation of functional caveolae, as indicated by colocalization of Na+-K+-ATPase with plasmalemmal vesicle-associated protein-1 by Förster resonance energy transfer and total internal reflection fluorescence microscopy. Our results suggest that elevated blood levels of Fg alter cerebrovascular permeability mainly by affecting caveolae-mediated transcytosis through modulation of de novo sphingolipid synthesis.
Experimental evidence and mathematical modeling of thermal effects on human colonic smooth muscle contractility
Authors: Altomare A. , Gizzi A. , Guarino M. P. L. , Loppini A. , Cocca S. , Dipaola M. , Alloni R. , Cicala M. , Filippi S.
Published: May 2014

It has been shown, in animal models, that gastrointestinal tract (GIT) motility is influenced by temperature; nevertheless, the basic mechanism governing thermal GIT smooth muscle responses has not been fully investigated. Studies based on physiologically tuned mathematical models have predicted that thermal inhomogeneity may induce an electrochemical destabilization of peristaltic activity. In the present study, the effect of thermal cooling on human colonic muscle strip (HCMS) contractility was studied. HCMSs were obtained from disease-free margins of resected segments for cancer. After removal of the mucosa and serosa layers, strips were mounted in separate chambers. After 30 min, spontaneous contractions developed, which were measured using force displacement transducers. Temperature was changed every hour (37, 34, and 31°C). The effect of cooling was analyzed on mean contractile activity, oscillation amplitude, frequency, and contraction to ACh (10−5M). At 37°C, HCMSs developed a stable phasic contraction (∼0.02 Hz) with a significant ACh-elicited mean contractile response (31% and 22% compared with baseline in the circular and longitudinal axis, respectively). At a lower bath temperature, higher mean contractile amplitude was observed, and it increased in the presence of ACh (78% and 43% higher than the basal tone in the circular and longitudinal axis, respectively, at 31°C). A simplified thermochemomechanical model was tuned on experimental data characterizing the stress state coupling the intracellular Ca2+concentration to tissue temperature. In conclusion, acute thermal cooling affects colonic muscular function. Further studies are needed to establish the exact mechanisms involved to better understand clinical consequences of hypothermia on intestinal contractile activity.
Elevated corticosterone in the dorsal hindbrain increases plasma norepinephrine and neuropeptide Y, and recruits a vasopressin response to stress
Authors: Daubert Daisy L. , Looney Benjamin M. , Clifton Rebekah R. , Cho Jake N. , Scheuer Deborah A.
Published: May 2014

Repeated stress and chronically elevated glucocorticoids cause exaggerated cardiovascular responses to novel stress, elevations in baseline blood pressure, and increased risk for cardiovascular disease. We hypothesized that elevated corticosterone (Cort) within the dorsal hindbrain (DHB) would: 1) enhance arterial pressure and neuroendocrine responses to novel and repeated restraint stress, 2) increase c-Fos expression in regions of the brain involved in sympathetic stimulation during stress, and 3) recruit a vasopressin-mediated blood pressure response to acute stress. Small pellets made of 10% Cort were implanted on the surface of the DHB in male Sprague-Dawley rats. Blood pressure was measured by radiotelemetry. Cort concentration was increased in the DHB in Cort-treated compared with Sham-treated rats (60 ± 15 vs. 14 ± 2 ng Cort/g of tissue, P < 0.05). DHB Cort significantly increased the integrated arterial pressure response to 60 min of restraint stress on days 6, 13, and 14 following pellet implantation (e.g., 731 ± 170 vs. 1,204 ± 68 mmHg/60 min in Sham- vs. Cort-treated rats, day 6, P < 0.05). Cort also increased baseline blood pressure by day 15 (99 ± 2 vs. 108 ± 3 mmHg for Sham- vs. Cort-treated rats, P < 0.05) and elevated baseline plasma norepinephrine and neuropeptide Y concentrations. Cort significantly enhanced stress-induced c-Fos expression in vasopressin-expressing neurons in the paraventricular nucleus of the hypothalamus, and blockade of peripheral vasopressin V1 receptors attenuated the effect of DHB Cort to enhance the blood pressure response to restraint. These data indicate that glucocorticoids act within the DHB to produce some of the adverse cardiovascular consequences of chronic stress, in part, by a peripheral vasopressin-dependent mechanism.
Cytochalasin E alters the cytoskeleton and decreases ENaC activity in Xenopus 2F3 cells
Authors: Reifenberger Matthew S. , Yu Ling , Bao Hui-Fang , Duke Billie Jeanne , Liu Bing-Chen , Ma He-Ping , Alli Ahmed A. , Eaton Douglas C. , Alli Abdel A.
Published: May 2014

Numerous reports have linked cytoskeleton-associated proteins with the regulation of epithelial Na+ channel (ENaC) activity. The purpose of the present study was to determine the effect of actin cytoskeleton disruption by cytochalasin E on ENaC activity in Xenopus 2F3 cells. Here, we show that cytochalasin E treatment for 60 min can disrupt the integrity of the actin cytoskeleton in cultured Xenopus 2F3 cells. We show using single channel patch-clamp experiments and measurements of short-circuit current that ENaC activity, but not its density, is altered by cytochalasin E-induced disruption of the cytoskeleton. In nontreated cells, 8 of 33 patches (24%) had no measurable ENaC activity, whereas in cytochalasin E-treated cells, 17 of 32 patches (53%) had no activity. Analysis of those patches that did contain ENaC activity showed channel open probability significantly decreased from 0.081 ± 0.01 in nontreated cells to 0.043 ± 0.01 in cells treated with cytochalasin E. Transepithelial current from mpkCCD cells treated with cytochalasin E, cytochalasin D, or latrunculin B for 60 min was decreased compared with vehicle-treated cells. The subcellular expression of fodrin changed significantly, and several protein elements of the cytoskeleton decreased at least twofold after 60 min of cytochalasin E treatment. Cytochalasin E treatment disrupted the association between ENaC and myristoylated alanine-rich C-kinase substrate. The results presented here suggest disruption of the actin cytoskeleton by different compounds can attenuate ENaC activity through a mechanism involving changes in the subcellular expression of fodrin, several elements of the cytoskeleton, and destabilization of the ENaC-myristoylated alanine-rich C-kinase substrate complex.
Spatial range and laminar structures of neuronal correlations in the cat primary visual cortex
Authors: Tanaka Hiroki , Tamura Hiroshi , Ohzawa Izumi
Published: May 2014

Activities of nearby cortical cells show temporal correlation on many timescales. In particular, previous studies of primary visual cortex (V1) indicate precise correlation on a timescale of milliseconds and loose correlation on a timescale of tens of milliseconds. To characterize cortical organization of these correlations, we investigated their spatial extent, laminar organization, and dependence on receptive field (RF) similarities. By simultaneously recording neuronal activity across layers within a horizontal distance of 1.2 mm, we found that loose correlation was widely observed for neuronal pairs horizontally or vertically separated over the whole distance range regardless of the layers. The incidence of loose correlation tended to be lower in layer 4 than in other layers. Loose correlation also accompanied a consistent delay in firing that was monotonically related to the vertical, but not horizontal, distance between the paired neurons. In contrast, the spatial range in which precise correlation was observed was more limited, with its incidence dropping sharply within 0.4 mm in both vertical and horizontal directions for all layers. With these spatial ranges, precise correlation was typically observed for pairs of neurons in the same layers, while loose correlation was often present even for pairs of neurons in widely separated layers. Furthermore, precise correlation was predominantly seen for pairs with similar RF properties, whereas loose correlation was seen even in pairs showing dissimilar properties. Our results show that neuronal correlations in V1 show markedly different structures for horizontal and vertical dimensions depending on correlation timescales.
Nonlinear EEG Decoding Based on a Particle Filter Model
Authors: Zhang Jinhua , Wei Jiongjian , Wang Baozeng , Hong Jun , Wang Jing
Published: May 2014

While the world is stepping into the aging society, rehabilitation robots play a more and more important role in terms of both rehabilitation treatment and nursing of the patients with neurological diseases. Benefiting from the abundant contents of movement information, electroencephalography (EEG) has become a promising information source for rehabilitation robots control. Although the multiple linear regression model was used as the decoding model of EEG signals in some researches, it has been considered that it cannot reflect the nonlinear components of EEG signals. In order to overcome this shortcoming, we propose a nonlinear decoding model, the particle filter model. Two- and three-dimensional decoding experiments were performed to test the validity of this model. In decoding accuracy, the results are comparable to those of the multiple linear regression model and previous EEG studies. In addition, the particle filter model uses less training data and more frequency information than the multiple linear regression model, which shows the potential of nonlinear decoding models. Overall, the findings hold promise for the furtherance of EEG-based rehabilitation robots.
Modeling and Simulation of Synchronous Threshold in Vent Collective Behavior
Authors: Zhang Yaofeng , Xiao Renbin
Published: May 2014

With the strengthening of the social contradiction, the outbreak of vent collective behavior tends to be frequent. The essence of vent collective behavior is emergence of synchronization. In order to explore the threshold of consensus synchronization in vent collective behavior, a mathematic model and a corresponding simulation model based on multi-agent are proposed. The results of analysis by mean field theory and simulation experiments show the following. (1) There is a thresholdKcfor consensus synchronization in global-coupling and homogeneous group, and when the system parameterKis greater thanKc, consensus synchronization emerge. Otherwise the system cannot achieve synchronization. The conclusion is verified by further study of multiagent simulation. (2) Compared with the global-coupling situation, the process of synchronization is delayed in local-coupling and homogeneous group. (3) For local-coupling and heterogeneous group, consensus dissemination can achieve synchronization only when the effects of the parameters meet the threshold requirements of consensus synchronization.