bluuebunny/crossref_metadata_2025 huggingface dataset:
Rise in optimized capillary channels
Authors: Figliuzzi B. , Buie C. R.
Published: August 2013

Many technological applications rely on the phenomenon of wicking flow induced by capillarity. However, despite a continuing interest in the subject, the influence of the capillary geometry on the wicking dynamics remains underexploited. In numerous applications, the ability to promote wicking in a capillary is a key issue. In this article, a model describing the capillary rise of a liquid in a capillary of varying circular cross-section is presented. The wicking dynamics is described by an ordinary differential equation with a term dependent upon the shape of the capillary channel. Using optimal control theory, we were able to design optimized capillaries which promote faster wicking than uniform cylinders. Numerical simulations show that the height of the rising liquid was up to 50 % greater with the optimized shapes than with a uniform cylinder of optimal radius. Experiments on specially designed capillaries with silicone oil show a good agreement with the theory. The methods presented can be useful in the design and optimization of systems employing capillary-driven transport including micro-heat pipes or oil extracting devices.
Inheritance of Cry1F resistance, cross-resistance and frequency of resistant alleles inSpodoptera frugiperda(Lepidoptera: Noctuidae)
Authors: Vélez A.M. , Spencer T.A. , Alves A.P. , Moellenbeck D. , Meagher R.L. , Chirakkal H. , Siegfried B.D.
Published: August 2013

Transgenic maize,Zea maizeL., expressing the Cry1F protein fromBacillus thuringiensishas been registered forSpodoptera frugiperda(J. E. Smith) control since 2003. Unexpected damage to Cry1F maize was reported in 2006 in Puerto Rico and Cry1F resistance inS. frugiperdawas documented. The inheritance of Cry1F resistance was characterized in aS. frugiperdaresistant strain originating from Puerto Rico, which displayed >289-fold resistance to purified Cry1F. Concentration–response bioassays of reciprocal crosses of resistant and susceptible parental populations indicated that resistance is recessive and autosomal. Bioassays of the backcross of the F1generation crossed with the resistant parental strain suggest that a single locus is responsible for resistance. In addition, cross-resistance to Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ba, Cry2Aa and Vip3Aa was assessed in the Cry1F-resistant strain. There was no significant cross-resistance to Cry1Aa, Cry1Ba and Cry2Aa, although only limited effects were observed in the susceptible strain. Vip3Aa was highly effective against susceptible and resistant insects indicating no cross-resistance with Cry1F. In contrast, low levels of cross-resistance were observed for both Cry1Ab and Cry1Ac. Because the resistance is recessive and conferred by a single locus, an F1screening assay was used to measure the frequency of Cry1F-resistant alleles from populations of Florida and Texas in 2010 and 2011. A total frequency of resistant alleles of 0.13 and 0.02 was found for Florida and Texas populations, respectively, indicating resistant alleles could be found in US populations, although there have been no reports of reduced efficacy of Cry1F-expressing plants.
Competition between honeydew producers in an ant–hemipteran interaction may enhance biological control of an invasive pest
Authors: Tena A. , Hoddle C.D. , Hoddle M.S.
Published: August 2013

Asian citrus psyllid,Diaphorina citriKuwayama (Hemiptera: Liviidae), is an invasive citrus pest in southern California, which secretes honeydew and has the potential to spread a lethal bacterial disease, huanglongbing, of citrus. In urban citrus, Argentine ant,Linepithema humile(Mayr) (Hymenoptera: Formicidae), also an invasive pest, tends honeydew-producing hemipterans. We used field data to determine whether the mutualistic relationship betweenL. humileand six established species of honeydew producers may hinder or favor the establishment ofD. citriand its biological control withTamarixia radiata(Waterston) (Hymenoptera: Eulophidae) in citrus via competition or mutualism for ants, respectively. In the field,L. humileandD. citriare engaged in a mutualistic relationship. Ants harvest solid honeydew secreted by psyllid nymphs and tended more than 55% of observedD. citricolonies.Linepithema humiledisplayed a preference hierarchy when tending honeydew producers infesting citrus. It responded equally or less intensively toD. citrithan to other honeydew-producing species. Consequently, the mutualism betweenL. humileandD. citriwas affected by the presence of other honeydew-producing species, and the percentage ofD. citricolonies tended byL. humile. The number of ants perD. citricolony also decreased as the number of other honeydew producers increased.Diaphorina citridensity was also affected by the presence of other honeydew producers. Both colony size and the number ofD. citrinymphs counted per tree decreased as the number of other honeydew producers increased. Our results indicate that competition between honeydew producers for the mutualist antL. humilemay hinder the establishment ofD. citriby possibly facilitating increased biological control.
Latin American Connections: Recent Work on German Interactions with Latin America
Authors: Penny H. Glenn
Published: August 2013

German interactions with Latin America have a long history. Indeed, early modern historians have demonstrated that people from German-speaking central Europe took part in all aspects of the European conquest of Central and South America. They have shown that these people were critical to mining operations and publishing in sixteenth-century Mexico; they have found them among Portuguese and Spanish sailors and soldiers almost everywhere; and they have located them playing important roles in a wide range of professions from Mexico to the south of Chile.
Einige Briefe Rosa Luxemburgs und Andere Dokumente
Authors: Rosa Daine
Published: August 2013

Die her mitgeteilten Briefe Rosa Luxernburgs entstammen zum grösseren Teil den Jahren 1898 bis 1902, also der Zeit des heftigsten Streites um den Revisionismus. Sie sind nicht nut Beiträge zur Biographie der Absenderin, insbesondere zur Kenntnis ihrer ersten Tätigkeit in der deutschen Arbeiterbewegung, die sich in der Redaktion derSächsischen Arbeiter Zeitungin Dresden abspielte; sondern sie sind darüber hinaus Dokumente, die den Kampf der beiden grossen Richtungen der deutschen Sozialdemokratie in einem seiner wichtigsten Abschnitte ansehaulich illustrieren. Zur Kennzeichnung der Atmosphare, in der sich diese innerparteilichen Auseinandersetzungen abspielten, wurden einige Stellen aus Briefen August Bebels, Karl Kautskys, Adolf Hoffmanns, Parvus', Clara Zetkins u. a. mitgeteilt. Die Briefe sind bisher unveroffentlicht und befinden sich in den Archiven des Internationalen Institutes fiir Sozialgeschichte.
Healing stories: Narrative characteristics in cancer survivorship narratives and psychological health among hematopoietic stem cell transplant survivors
Authors: Benish-Weisman Maya , Wu Lisa M. , Weinberger-Litman Sarah L. , Redd William H. , Duhamel Katherine N. , Rini Christine
Published: August 2013

Objectives:

Survivors of hematopoietic stem cell transplant (HSCT) have experienced a life threatening and potentially traumatic illness and treatment that make them vulnerable to long lasting negative psychological outcomes, including anxiety and depression. Nevertheless, studies show that overcoming cancer and its treatment can present an opportunity for personal growth and psychological health (reduced symptoms of anxiety and depression and high levels of emotional well-being) through resilience. However, research has not yet clarified what differentiates HSCT survivors who experience psychological growth from those who do not. By analyzing recovery narratives, we examined whether HSCT survivors’ interpretation of their experiences helps explain differences in their post-treatment psychological health.

Methods:

Guided by narrative psychology theory, we analyzed the narratives of 23 HSCT survivors writing about their experience of cancer treatment. Psychological health was measured by: (1) emotional well-being subscale part of the Functional Assessment of Cancer Therapy Bone Marrow Transplant (FACT-BMT), (2) depression, and (3) anxiety subscales of the Brief Symptom Inventory.

Results:

Findings revealed a positive relation between psychological health and a greater number of redemption episodes (going from an emotionally negative life event to an emotionally positive one) as well as fewer negative emotional expressions.

Significance of the results:

Theoretical and practical implications of these findings are discussed, showing how narratives can inform interventions to assist cancer survivors with their psychological recovery.
Cost Effectiveness of a Community-Based Crisis Intervention Program for People Bereaved by Suicide
Authors: Comans Tracy , Visser Victoria , Scuffham Paul
Published: August 2013

Background: Postvention services aim to ameliorate distress and reduce future incidences of suicide. The StandBy Response Service is one such service operating in Australia for those bereaved through suicide. Few previous studies have reported estimates or evaluations of the economic impact and outcomes associated with the implementation of bereavement/grief interventions. Aims: To estimate the cost-effectiveness of a postvention service from a societal perspective. Method: A Markov model was constructed to estimate the health outcomes, quality-adjusted life years, and associated costs such as medical costs and time off work. Data were obtained from a prospective cross-sectional study comparing previous clients of the StandBy service with a control group of people bereaved by suicide who had not had contact with StandBy. Costs and outcomes were measured at 1 year after suicide bereavement and an incremental cost-effectiveness ratio was calculated. Results: The base case found that the StandBy service dominated usual care with a cost saving from providing the StandBy service of AUS $803 and an increase in quality-adjusted life years of 0.02. Probabilistic sensitivity analysis indicates there is an 81% chance the service would be cost-effective given a range of possible scenarios. Conclusion: Postvention services are a cost-effective strategy and may even be cost-saving if all costs to society from suicide are taken into account.
Association Between Psychopathology and Suicidal Behavior In Schizophrenia
Authors: Jovanović Nikolina , Podlesek Anja , Medved Vesna , Grubišin Jasmina , Mihaljevic-Peleš Alma , Goran Tošić , Lovretić Vanja
Published: August 2013

Background: Suicide in schizophrenia is a serious problem – ideation rates go up to 40%, and approximately one half of patients attempt suicide at least once. The distinction between attempters and ideators is vital in everyday clinical practice. Aim: To explore the association between psychopathology and suicidal behavior in a comparative study of three groups of patients with schizophrenia: suicide ideators, suicide attempters, and subjects without suicide ideation and behavior. Method: The study included 509 patients: suicide attempters (n = 159), ideators (n = 180), and a comparative group (n = 170). The clinical assessment consisted of a structured psychiatric interview and an evaluation of sociodemographics, suicidality (SIBQ), psychopathology (PANSS), and depression (CDSS). Results: Suicide attempters were more depressed than ideators, and both groups had higher CDSS scores than the comparative group. The overall contribution of positive, negative, and general PANSS symptoms was not statistically significant enough to differentiate ideators from attempters. A principal component analysis of the PANSS items revealed five components: disinhibition, withdrawal, anxiety and guilt, reality distortion, and disorganization. Two logistic regression analyses showed that suicide ideation or attempt was significantly related to depression, anxiety, guilt, gender, age, and number of previous hospitalizations. Compared to suicide ideators, attempters were more depressed, had a higher number of previous hospitalizations, and lower education. Conclusion: The results indicate that clinicians should look for depression, anxiety, and guilt feelings, while positive and negative symptoms seem to be less relevant for suicide assessment in schizophrenia.
The Influence of Noise on Bold-Mediated Vessel Size Imaging Analysis Methods
Authors: Germuska Michael A , Meakin James A , Bulte Daniel P
Published: August 2013

Vessel size imaging (VSI) is a magnetic resonance imaging (MRI) technique that aims to provide quantitative measurements of tissue microvasculature. An emerging variation of this technique uses the blood oxygenation level-dependent (BOLD) effect as the source of the imaging contrast. Gas challenges have the advantage over contrast injection techniques in that they are noninvasive and easily repeatable because of the fast washout of the contrast. However, initial results from BOLD-VSI studies are somewhat contradictory, with substantially different estimates of the mean vessel radius. Owing to BOLD-VSI being an emerging technique, there is not yet a standard processing methodology, and different techniques have been used to calculate the mean vessel radius and reject uncertain estimates. In addition, the acquisition methodology and signal modeling vary from group to group. Owing to these differences, it is difficult to determine the source of this variation. Here we use computer modeling to assess the impact of noise on the accuracy and precision of different BOLD-VSI calculations. Our results show both potential overestimates and underestimates of the mean vessel radius, which is confirmed with a validation study at 3T.
Age-Related Autoregulatory Dysfunction and Cerebromicrovascular Injury in Mice with Angiotensin II-induced Hypertension
Authors: Toth Peter , Tucsek Zsuzsanna , Sosnowska Danuta , Gautam Tripti , Mitschelen Matthew , Tarantini Stefano , Deak Ferenc , Koller Akos , Sonntag William E , Csiszar Anna , Ungvari Zoltan
Published: August 2013

Hypertension in the elderly substantially contributes to cerebromicrovascular damage and promotes the development of vascular cognitive impairment. Despite the importance of the myogenic mechanism in cerebromicrovascular protection, it is not well understood how aging affects the functional adaptation of cerebral arteries to high blood pressure. Hypertension was induced in young (3 months) and aged (24 months) C57/BL6 mice by chronic infusion of angiotensin II (AngII). In young hypertensive mice, the range of cerebral blood flow autoregulation was extended to higher pressure values, and the pressure-induced tone of middle cerebral artery (MCA) was increased. In aged hypertensive mice, autoregulation was markedly disrupted, and MCAs did not show adaptive increases in myogenic tone. In young mice, the mechanism of adaptation to hypertension involved upregulation of the 20-HETE (20-hydroxy-5,8,11,14-eicosatetraenoic acid)/transient receptor potential cation channel, subfamily C (TRPC6) pathway and this mechanism was impaired in aged hypertensive mice. Downstream consequences of cerebrovascular autoregulatory dysfunction in aged AngII-induced hypertensive mice included exacerbated disruption of the blood–brain barrier and neuroinflammation (microglia activation and upregulation of proinflammatory cytokines and chemokines), which were associated with impaired hippocampal dependent cognitive function. Collectively, aging impairs autoregulatory protection in the brain of mice with AngII-induced hypertension, potentially exacerbating cerebromicrovascular injury and neuroinflammation.
Neuroprotective Effects of Geranylgeranylacetone in Experimental Traumatic Brain Injury
Authors: Zhao Zaorui , Faden Alan I , Loane David J , Lipinski Marta M , Sabirzhanov Boris , Stoica Bogdan A
Published: August 2013

Geranylgeranylacetone (GGA) is an inducer of heat-shock protein 70 (HSP70) that has been used clinically for many years as an antiulcer treatment. It is centrally active after oral administration and is neuroprotective in experimental brain ischemia/stroke models. We examined the effects of single oral GGA before treatment (800 mg/kg, 48 hours before trauma) or after treatment (800 mg/kg, 3 hours after trauma) on long-term functional recovery and histologic outcomes after moderate-level controlled cortical impact, an experimental traumatic brain injury (TBI) model in mice. The GGA pretreatment increased the number of HSP70+ cells and attenuated posttraumatic α-fodrin cleavage, a marker of apoptotic cell death. It also improved sensorimotor performance on a beam walk task; enhanced recovery of cognitive/affective function in the Morris water maze, novel object recognition, and tail-suspension tests; and improved outcomes using a composite neuroscore. Furthermore, GGA pretreatment reduced the lesion size and neuronal loss in the hippocampus, cortex, and thalamus, and decreased microglial activation in the cortex when compared with vehicle-treated TBI controls. Notably, GGA was also effective in a posttreatment paradigm, showing significant improvements in sensorimotor function, and reducing cortical neuronal loss. Given these neuroprotective actions and considering its longstanding clinical use, GGA should be considered for the clinical treatment of TBI.
Microglia/Macrophage Polarization Dynamics in White Matter after Traumatic Brain Injury
Authors: Wang Guohua , Zhang Jia , Hu Xiaoming , Zhang Lili , Mao Leilei , Jiang Xiaoyan , Liou Anthony Kian-Fong , Leak Rehana K , Gao Yanqin , Chen Jun
Published: August 2013

Mononuclear phagocytes are a population of multi-phenotypic cells and have dual roles in brain destruction/reconstruction. The phenotype-specific roles of microglia/macrophages in traumatic brain injury (TBI) are, however, poorly characterized. In the present study, TBI was induced in mice by a controlled cortical impact (CCI) and animals were killed at 1 to 14 days post injury. Real-time polymerase chain reaction (RT–PCR) and immunofluorescence staining for M1 and M2 markers were performed to characterize phenotypic changes of microglia/macrophages in both gray and white matter. We found that the number of M1-like phagocytes increased in cortex, striatum and corpus callosum (CC) during the first week and remained elevated until at least 14 days after TBI. In contrast, M2-like microglia/macrophages peaked at 5 days, but decreased rapidly thereafter. Notably, the severity of white matter injury (WMI), manifested by immunohistochemical staining for neurofilament SMI-32, was strongly correlated with the number of M1-like phagocytes. In vitro experiments using a conditioned medium transfer system confirmed that M1 microglia-conditioned media exacerbated oxygen glucose deprivation–induced oligodendrocyte death. Our results indicate that microglia/macrophages respond dynamically to TBI, experiencing a transient M2 phenotype followed by a shift to the M1 phenotype. The M1 phenotypic shift may propel WMI progression and represents a rational target for TBI treatment.
Blood Flow Distribution during Heat Stress: Cerebral and Systemic Blood Flow
Authors: Ogoh Shigehiko , Sato Kohei , Okazaki Kazunobu , Miyamoto Tadayoshi , Hirasawa Ai , Morimoto Keiko , Shibasaki Manabu
Published: August 2013

The purpose of the present study was to assess the effect of heat stress-induced changes in systemic circulation on intra- and extracranial blood flows and its distribution. Twelve healthy subjects with a mean age of 22±2 (s.d.) years dressed in a tube-lined suit and rested in a supine position. Cardiac output (Q), internal carotid artery (ICA), external carotid artery (ECA), and vertebral artery (VA) blood flows were measured by ultrasonography before and during whole body heating. Esophageal temperature increased from 37.0±0.2°C to 38.4±0.2°C during whole body heating. Despite an increase in Q (59±31%, P<0.001), ICA and VA decreased to 83±15% ( P=0.001) and 87±8% ( P=0.002), respectively, whereas ECA blood flow gradually increased from 188±72 to 422±189 mL/minute (+135%, P<0.001). These findings indicate that heat stress modified the effect of Q on blood flows at each artery; the increased Q due to heat stress was redistributed to extracranial vascular beds.
A Generic Integrated Physiologically based Whole‐body Model of the Glucose‐Insulin‐Glucagon Regulatory System
Authors: Schaller S , Willmann S , Lippert J , Schaupp L , Pieber TR , Schuppert A , Eissing T
Published: August 2013

Models of glucose metabolism are a valuable tool for fundamental and applied medical research in diabetes. Use cases range from pharmaceutical target selection to automatic blood glucose control. Standard compartmental models represent little biological detail, which hampers the integration of multiscale data and confines predictive capabilities. We developed a detailed, generic physiologically based whole‐body model of the glucose‐insulin‐glucagon regulatory system, reflecting detailed physiological properties of healthy populations and type 1 diabetes individuals expressed in the respective parameterizations. The model features a detailed representation of absorption models for oral glucose, subcutaneous insulin and glucagon, and an insulin receptor model relating pharmacokinetic properties to pharmacodynamic effects. Model development and validation is based on literature data. The quality of predictions is high and captures relevant observed inter‐ and intra‐individual variability. In the generic form, the model can be applied to the development and validation of novel diabetes treatment strategies.

CPT: Pharmacometrics & Systems Pharmacology (2013) 2, e65; doi:10.1038/psp.2013.40; published online 14 August 2013
Basic Concepts in Physiologically Based Pharmacokinetic Modeling in Drug Discovery and Development
Authors: Jones HM , Rowland‐Yeo K
Published: August 2013

The aim of this tutorial is to introduce the concept of physiologically based pharmacokinetic (PBPK) modeling to individuals in the pharmaceutical industry who may be relatively new to this area and to demonstrate application of this approach in a preclinical and clinical setting. The tutorial provides some background on PBPK models and their data requirements, introduces strategies for PBPK modeling in drug development, and includes a discussion on regulatory considerations and potential resource issues.

CPT: Pharmacometrics & Systems Pharmacology (2013) 2, e63; doi:10.1038/psp.2013.41; published online 14 August 2013
Deep subwavelength fourfold rotationally symmetric split-ring-resonator metamaterials for highly sensitive and robust biosensing platform
Authors: Tobing Landobasa Y. M. , Tjahjana Liliana , Zhang Dao Hua , Zhang Qing , Xiong Qihua
Published: August 2013

Metamaterials provide a good platform for biochemical sensing due to its strong field localization at nanoscale. In this work, we show that electric and magnetic resonant modes in split-ring-resonator (SRR) can be efficiently excited under unpolarized light illumination when the SRRs are arranged in fourfold rotationally symmetric lattice configuration. The fabrication and characterization of deep subwavelength (~λ/15) gold-based SRR structures with resonator size as small as ~ 60 nm are reported with magnetic resonances in Vis-NIR spectrum range. The feasibility for sensing is demonstrated with refractive index sensitivity as high as ~ 636 nm/RIU.
Synthesis of novel trithiocarbonate and allyl sulfide containing monomers
Authors: Fenoli Christopher R. , Bowman Christopher N.
Published: August 2013

A novel, mild, and high yielding synthesis is developed for trithiocarbonate and allyl sulphide-containing AFT (addition–fragmentation termination) monomers. The image illustrates the novel core, linker, and end groups of the monomer array crosslinked by PETMP, through which polymer films of low stress and capable of photoplasticity may be formed.
Identification of a specific one amino acid change in recombinant human transglutaminase 2 that regulates its activity and calcium sensitivity
Authors: Kanchan Kajal , Ergülen Elvan , Király Robert , Simon-Vecsei Zsófia , Fuxreiter Mónika , Fésüs László
Published: August 2013

TG2 (transglutaminase 2) is a calcium-dependent protein cross-linking enzyme which is involved in a variety of cellular processes. The threshold level of calcium needed for endogenous and recombinant TG2 activity has been controversial, the former being more sensitive to calcium than the latter. In the present study we address this question by identifying a single amino acid change from conserved valine to glycine at position 224 in recombinant TG2 compared with the endogenous sequence present in the available genomic databases. Substituting a valine residue for Gly224 in the recombinant TG2 increased its calcium-binding affinity and transamidation activity 10-fold and isopeptidase activity severalfold, explaining the inactivity of widely used recombinant TG2 at physiological calcium concentrations. ITC (isothermal titration calorimetry) measurements showed 7-fold higher calcium-binding affinities for TG2 valine residues which could be activated inside cells. The two forms had comparable substrate- and GTP-binding affinities and also bound fibronectin similarly, but coeliac antibodies had a higher affinity for TG2 valine residues. Structural analysis indicated a higher stability for TG2 valine residues and a decrease in flexibility of the calcium-binding loop resulting in improved metal-binding affinity. The results of the present study suggest that Val224 increases TG2 activity by modulating its calcium-binding affinity enabling transamidation reactions inside cells.
Passive acoustic localisation using blind Gauss–Markov estimate with spectral estimation at each sensor
Authors: Choudhary Hemlata , Bahl Rajendar , Kumar Arun
Published: August 2013

Time‐delay estimation has essential applications in the field of radar, sonar and robotics. For a very distant source, time‐delay vector estimation across an M‐sensor array is realised using the generalised cross‐correlation (GCC) function and the estimates combined with their covariance matrix, expressed in terms of a priori known signal and noise spectra, to yield a linear minimum variance unbiased estimator, known as the Gauss–Markov Estimate. In the absence of a priori information, spectral estimation has to be done at one of the sensors. For close range sources, the use of amplitude attenuation information across the array will improve this estimate further. This study presents a new amplitude information related Gauss–Markov estimate, which calculates the power spectral density (PSD) at all the sensors of the array and gives more accurate time delay estimates in terms of the mean‐square error when compared to the earlier constant amplitude‐based technique using the PSD at the closest sensor. The performance has been evaluated against signal‐to‐noise ratio for varying distance of a source from the receiving array. The results have been verified by simulations and experiments for a two‐dimensional source localisation problem.
Advanced range migration algorithm for ultra‐high resolution spaceborne synthetic aperture radar
Authors: Zeng Tao , Yang Wenfu , Ding Zegang , Liu Luosi
Published: August 2013

To achieve ultra‐high resolution images, processing algorithm of spaceborne synthetic aperture radar (SAR) faces significant challenges such as the curved orbit, the unneglectable propagation time and the space‐variant effective velocity. In the light of imaging requirements of the ultra‐high resolution spaceborne SAR, an advanced range migration algorithm (ARMA) is presented in this study. Firstly, a new slant range model is developed by incorporating straight orbit approximation with additional linear, cubic and quartic term. Subsequently, a two‐dimensional spectrum is derived by making use of Fourier transform pairs and the approximate azimuth stationary point based on the new range model. Finally, a novel RMA is derived. In this algorithm, the accurate range cell migration correction (RCMC) is done through two steps: the effective velocity dependence RCMC and the bulk RCMC, and the range‐variant azimuth filtering is accomplished. Simulations are carried out to verify our proposed algorithm, which indicate that ARMA can keep precise even the resolution is up to decimeter level.
Discrete chirp‐Fourier transform‐based acquisition algorithm for weak global positioning system L5 signals in high dynamic environments
Authors: Fan Bo , Zhang Kai , Qin Yuliang , Wang Hongqiang , Xiao Huaitie
Published: August 2013

For the acquisition of weak global positioning system L5 signals in high dynamic environments, coherent integration time is necessarily extended for signal‐to‐noise ratio improvement. However, the incidental problems, such as high‐rate sign transitions, tiered codes and particularly the concurrence of Doppler shift and Doppler rate, will bring challenges to the acquisition. This study proposes a novel acquisition algorithm based on the discrete chirp‐Fourier transform (DCFT) to solve the problems above. The 1 ms complex correlation is modelled as a chirp signal to account for high dynamics effect. Then the DCFT is introduced to simultaneously estimate the Doppler shift and Doppler rate residuals. In this way, the 1 ms complex correlations are coherently post‐integrated and a high processing gain can be obtained when both the primary and secondary code phases are aligned. Furthermore, the false alarm and detection probabilities are derived to statistically characterise the acquisition performance. Simulation results demonstrate that the proposed algorithm is tolerant of high dynamics and robust to noise. Specifically, it can acquire the L5 signal with up to 20 g acceleration and only 25 dB Hz carrier‐to‐noise ratio, which is impossible for the conventional fast Fourier transform scheme.
New scaling function processing approach for mono‐static terrain imaging radar
Authors: Ha Jong Soo , Park Gyu Churl , Cho Byung Lae , Lee Jung Soo , Sun Sun Gu
Published: August 2013

To increase the mobility of an unmanned ground vehicle, this study describes new approach to detect targets in front of mono‐static terrain imaging radar (TIR), which is a prototypical ground‐based forward looking radar. Since the TIR employs a mono‐static configuration and a real aperture antenna array, the conventional back‐projection method is very useful in spite of its poor processing time. However, it is difficult to employ another method because the TIR is an ultra‐wide‐band type of radar and employs a dechirp‐on‐receive process. To overcome these difficulties, a new approach based on scaling function processing is proposed in this study. This scaling function is based on a spectral analysis approach and the proposed method conducts range cell migration compensation, secondary range compression and azimuth compression using this scaling function. In this study, the complete derivation of the proposed method is presented. A very useful formulation for a dechirped mono‐static radar signal in the range Doppler domain is also proposed, in which the signal is expressed by the scaling function. The results of simulations and field tests are demonstrated to show the performance and validity of the proposed method.
Reconfigurable sum–difference pattern by means of parasitic elements for forward‐looking monopulse radar
Authors: Rocca Paolo , Donelli Massimo , Oliveri Giacomo , Viani Federico , Massa Andrea
Published: August 2013

This study describes the design of forward‐looking monopulse arrays able to reconfigure the radiation pattern from the sum mode to the difference one by electronically switching a set of parasitic dipoles placed in front of a driven array of radiating dipoles. The antenna architecture is synthesised by optimising the geometric parameters of the passive elements, namely their positions and lengths. The generation of the difference beam is yielded by imposing a phase displacement of π to the excitations of half active array and activating the parasitic array by turning‐on the switches that partition their lengths. As for the sum pattern, the effect of the parasitic dipoles is made negligible by turning‐off the switches. A set of representative results is reported and discussed to show the effectiveness of the proposed approach.
The role of leaf hydraulic conductance dynamics on the timing of leaf senescence
Authors: Giraldo Juan Pablo , Wheeler James K. , Huggett Brett A. , Holbrook N. Michele
Published: August 2013

We tested the hypothesis that an age-dependent reduction in leaf hydraulic conductance (Kleaf) influences the timing of leaf senescence via limitation of the stomatal aperture on xylem compound delivery to leaves of tomato (Solanum lycopersicum L.), the tropical trees Anacardium excelsum Kunth, Pittoniotis trichantha Griseb, and the temperate trees Acer saccharum Marsh. and Quercus rubra L. The onset of leaf senescence was preceded by a decline in Kleaf in tomato and the tropical trees, but not in the temperate trees. Age-dependent changes in Kleaf in tomato were driven by a reduction in leaf vein density without a proportional increase in the xylem hydraulic supply. A decline in stomatal conductance accompanied Kleaf reduction with age in tomato but not in tropical and temperate tree species. Experimental manipulations that reduce the flow of xylem-transported compounds into leaves with open stomata induced early leaf senescence in tomato and A. excelsum, but not in P. trichantha, A. saccharum and Q. rubra leaves. We propose that in tomato, a reduction in Kleaf limits the delivery of xylem-transported compounds into the leaves, thus making them vulnerable to senescence. In the tropical evergreen tree A. excelsum, xylem-transported compounds may play a role in signalling the timing of senescence but are not under leaf hydraulic regulation; leaf senescence in the deciduous trees A. trichanta, A. saccharum and Q. rubra is not influenced by leaf vascular transport.
Nucleic acid determinants for selective deamination of DNA over RNA by activation-induced deaminase
Authors: Nabel Christopher S. , Lee Jae W. , Wang Laura C. , Kohli Rahul M.
Published: August 2013

Activation-induced deaminase (AID), a member of the larger AID/APOBEC family, is the key catalyst in initiating antibody somatic hypermutation and class-switch recombination. The DNA deamination model accounting for AID’s functional role posits that AID deaminates genomic deoxycytosine bases within the immunoglobulin locus, activating downstream repair pathways that result in antibody maturation. Although this model is well supported, the molecular basis for AID’s selectivity for DNA over RNA remains an open and pressing question, reflecting a broader need to elucidate how AID/APOBEC enzymes engage their substrates. To address these questions, we have synthesized a series of chimeric nucleic acid substrates and characterized their reactivity with AID. These chimeric substrates feature targeted variations at the 2′-position of nucleotide sugars, allowing us to interrogate the steric and conformational basis for nucleic acid selectivity. We demonstrate that modifications to the target nucleotide can significantly alter AID’s reactivity. Strikingly, within a substrate that is otherwise DNA, a single RNA-like 2′-hydroxyl substitution at the target cytosine is sufficient to compromise deamination. Alternatively, modifications that favor a DNA-like conformation (or sugar pucker) are compatible with deamination. AID’s closely related homolog APOBEC1 is similarly sensitive to RNA-like substitutions at the target cytosine. Inversely, with unreactive 2′-fluoro-RNA substrates, AID’s deaminase activity was rescued by introducing a trinucleotide DNA patch spanning the target cytosine and two nucleotides upstream. These data suggest a role for nucleotide sugar pucker in explaining the molecular basis for AID’s DNA selectivity and, more generally, suggest how other nucleic acid-modifying enzymes may distinguish DNA from RNA.
R-spondin3 prevents mesenteric ischemia/reperfusion-induced tissue damage by tightening endothelium and preventing vascular leakage
Authors: Kannan Lakshmi , Kis-Toth Katalin , Yoshiya Kazuhisa , Thai To-Ha , Sehrawat Seema , Mayadas Tanya N. , Dalle Lucca Jurandir J. , Tsokos George C.
Published: August 2013

Inflammation and vascular injury triggered by ischemia/reperfusion (I/R) represent a leading cause of morbidity and mortality in a number of clinical settings. Wnt and its homolog partners R-spondins, in addition to regulating embryonic development have recently been demonstrated to serve as wound-healing agents in inflammation-associated conditions. Here we ask whether R-spondins could prevent inflammation-associated tissue damage in ischemic disorders and thus investigate the role of R-spondin3 (R-spo3) in a mouse model of mesenteric I/R. We demonstrate that R-spo3 ameliorates mesenteric I/R-induced local intestinal as well as remote lung damage by suppressing local and systemic cytokine response and deposition of IgM and complement in intestinal tissues. We also show that decreased inflammatory response is accompanied by tightening of endothelial cell junctions and reduction in vascular leakage. We conclude that R-spo3 stabilizes endothelial junctions and inhibits vascular leakage during I/R and thereby mitigates the inflammatory events and associated tissue damage. Our findings uniquely demonstrate a protective effect of R-spo3 in I/R-related tissue injury and suggest a mechanism by which it may have these effects.
Super Trawler Scuppered in Australian Fisheries Management Reform
Authors: Tracey Sean , Buxton Colin , Gardner Caleb , Green Bridget , Hartmann Klaas , Haward Marcus , Jabour Julia , Lyle Jeremy , McDonald Jan
Published: August 2013

In response to an intense social media campaign led by international conservation groups, Green politicians, and recreational fishers, the Australian government imposed a moratorium on the operations of a large factory trawler. This moratorium overrode the government's own independent fisheries management process by making amendments to its key environmental legislation just days prior to the commencement of fishing by this vessel. Concurrently, the government announced a comprehensive review of Australia's fisheries management legislation. Whereas science is usually deployed in support of conservation in natural resource conflicts, in this case science-based fisheries management advice took a back seat to vociferous protest by interest groups, perpetuated by the media (in particular social media), ultimately culminating in a contentious political decision.

RESUMEN

En respuesta a las intensas campañas de los medios sociales, dirigidas por grupos de conservación internacionales, políticos de tendencia verde y pescadores recreativos, el gobierno australiano impuso una moratoria a las operaciones de un mega-barco arrastrero. Esta moratoria ignora el proceso de manejo pesquero desarrollado de forma independiente por el propio gobierno, modificando la legislación ambiental días previos a que la embarcación comenzara sus actividades de pesca. Actualmente, el gobierno anunció que se haría una revisión exhaustiva de la legislación de manejo de las pesquerías australianas. Si bien la ciencia se utiliza con frecuencia para apoyar la conservación de los conflictos concernientes a los recursos naturales, en este caso, las recomendaciones de manejo basadas en evidencia científica fueron relegadas por protestas vociferantes de grupos de posición y perpetuadas por los medios (particularmente por los medios sociales), culminando finalmente en una decisión política.
From Gestures to Gaming: Visible Embodiment of Remote Actions
Authors: Chisholm Joseph D. , Risko Evan F. , Kingstone Alan
Published: August 2013

Teleoperation is the act of controlling an object that exists in a space, real or virtual, physically disconnected from the user. During such situations, it is not uncommon to observe those controlling the remote object exhibiting movement consistent with the behaviour of the remote object. Though this behaviour has no obvious impact on one's control of the remote object, it appears tied to one's intentions, thus, possibly representing an embodied representation of ongoing cognitive processes. In the present investigation, we applied a natural behaviour approach to test this notion, (a) first by identifying the representational basis for the behaviour and (b) by identifying factors that influence the occurrence of the behaviour. Each study involved observing participant behaviour while they played a racing video game. Results revealed that the spontaneous behaviour demonstrated in a teleoperation setting is tied to one's remote actions, rather than local actions or some combination of remote and local actions (Experiment 1). In addition, increasing task demand led to an increase in the occurrence of the spontaneous behaviour (Experiment 2). A third experiment was conducted to rule out the possible confound of greater immersion that tends to accompany greater demand (Experiment 3). The implications of these results not only suggest that spontaneous behaviour observed during teleoperation reflects a form of visible embodiment, sensitive to task demand, but also further emphasizes the utility of natural behaviour approaches for furthering our understanding of the relationship between the body and cognitive processes.
Refined bounds for the eigenvalues of the Klein-Gordon operator
Authors: Yolcu Türkay
Published: August 2013

The aim of this article is twofold. First we establish sharper lower bounds for the sums of eigenvalues of

(
−
Δ

)

1
2

|

D

,

(-\Delta )^{\frac {1}{2}}|_{D},

the Klein-Gordon operator restricted to a bounded domain

D
⊂

R

d

,

D\subset {\mathbb R}^d,

than the bounds obtained in works by E. Harrell; S. Yıldırım Yolcu; and G. Wei, H. Sun, and L. Zeng. Then we study upper bounds for the sums of negative powers of the eigenvalues of

(
−
Δ

)

1
2

|

D

.

(-\Delta )^{\frac {1}{2}}|_{D}.
Kähler-Ricci flow on projective bundles over Kähler-Einstein manifolds
Authors: Fong Frederick Tsz-Ho
Published: August 2013

We study the Kähler-Ricci flow on a class of projective bundles

P

(

O

Σ

⊕
L
)

\mathbb {P}(\mathcal {O}_\Sigma \oplus L)

over the compact Kähler-Einstein manifold

Σ
n

\Sigma ^n

. Assuming the initial Kähler metric

ω
0

\omega _0

admits a

U
(
1
)

U(1)

-invariant momentum profile, we give a criterion, characterized by the triple

(
Σ
,
L
,
[

ω
0

]
)

(\Sigma , L, [\omega _0])

, under which the

P

1

\mathbb {P}^1

-fiber collapses along the Kähler-Ricci flow and the projective bundle converges to

Σ
\Sigma

in the Gromov-Hausdorff sense. Furthermore, the Kähler-Ricci flow must have Type I singularity and is of

(

C

n

×

P

1

)

(\mathbb {C}^n \times \mathbb {P}^1)

-type. This generalizes and extends part of Song-Weinkove’s work on Hirzebruch surfaces.
Coral recruitment: the critical role of early post-settlement survival
Authors: Martinez Stephane , Abelson Avigdor
Published: August 2013

Martinez, S., and Abelson, A. 2013. Coral recruitment: the critical role of early post-settlement survival. – ICES Journal of Marine Science, 70: . Coral recruitment is a pivotal factor in coral reef stability and in recovery following substantial disturbances. Despite its immense importance, the study of coral recruitment has some major gaps, notably larval survival before and following settlement, mainly due to technical limitations, which stem from the difficulty in observing the minute larvae. To overcome the major limitation in coral recruitment studies, i.e. the in situ detection of recruits during their early stages, we designed a new detection set-up, composed of a fluorescence detection set-up, a grid-covered substrate, and a Geographic Information System tracking system. This set-up, enabling the identification of coral recruits soon after settlement, revealed that in the critical period of the first day, less than 45% of the settling corals may survive. The results also suggest that either coral larva select locations that may increase their survival chances or they experience dramatic mortality during the early hours of settlement, which induce a consistent pattern of spat distribution. Our study confirms an earlier speculation that the first 24 h post-settlement may determine the rates and spatial patterns of recruitment. The significant implications of these findings, and the implemented “detection set-up” for coral reef monitoring and management, are discussed.
Incorporating density dependence in pup production in a stock assessment of NE Atlantic spurdog Squalus acanthias
Authors: De Oliveira José A. A. , Ellis James R. , Dobby Helen
Published: August 2013

De Oliveira, J. A. A., Ellis, J. R., and Dobby, H. 2013. Incorporating density dependence in pup production in a stock assessment of NE Atlantic spurdog Squalus acanthias. – ICES Journal of Marine Science, 70: . An age- and sex-structured stock assessment model for Northeast Atlantic spurdog Squalus acanthias is presented that includes length-based processes, such as maturation, pup production, growth, and gear selectivity, with a length-at-age relationship to convert length to age. It relates pup production functionally to numbers of pregnant females, allowing for density-dependent effects. The model was fitted to a combined Scottish groundfish survey biomass index, to proportion-by-length category data from both trawl surveys and commercial catch sampling from target and non-target fisheries, and to fecundity data. The model was run from 1905 to better reflect virgin conditions and to allow early fecundity data to be fitted in order to estimate the extent of density dependence in pup production. The model estimated 2010 population levels to be about 23% relative to 1955 and 19% relative to 1905. Results confirm that the stock is depleted, but not to the extent estimated in a previous assessment. Current estimates of depletion would support an IUCN listing of “Endangered”, but not “Critically Endangered”. Model projections showed that a TAC of 1422 t (the last non-zero TAC) would allow future population growth.
A Recessive Resistance to Rice yellow mottle virus Is Associated with a Rice Homolog of the CPR5 Gene, a Regulator of Active Defense Mechanisms
Authors: Orjuela Julie , Deless E. F. Thiémélé , Kolade Olufisayo , Chéron Sophie , Ghesquière Alain , Albar Laurence
Published: August 2013

RYMV2 is a major recessive resistance gene identified in cultivated African rice (Oryza glaberrima) which confers high resistance to the Rice yellow mottle virus (RYMV). We mapped RYMV2 in an approximately 30-kb interval in which four genes have been annotated. Sequencing of the candidate region in the resistant Tog7291 accession revealed a single mutation affecting a predicted gene, as compared with the RYMV-susceptible O. glaberrima CG14 reference sequence. This mutation was found to be a one-base deletion leading to a truncated and probably nonfunctional protein. It affected a gene homologous to the Arabidopsis thaliana CPR5 gene, known to be a defense mechanism regulator. Only seven O. glaberrima accessions showing this deletion were identified in a collection consisting of 417 accessions from three rice species. All seven accessions were resistant to RYMV, which is an additional argument in favor of the involvement of the deletion in resistance. In addition, fine mapping of a resistance quantitative trait locus in O. sativa advanced backcrossed lines pinpointed a 151-kb interval containing RYMV2, suggesting that allelic variants of the same gene may control both high and partial resistance.