bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrogen and major element concentrations on 433 Eros: Evidence for an L‐ orLL‐chondrite‐like surface composition
Authors: Peplowski Patrick N. , Bazell David , Evans Larry G. , Goldsten John O. , Lawrence David J. , Nittler Larry R. 
Published: March 2015

AbstractA reanalysis ofNEARX‐ray/gamma‐ray spectrometer (XGRS) data provides robust evidence that the elemental composition of the near‐Earth asteroid 433 Eros is consistent with the L andLLordinary chondrites. These results facilitated the use of the gamma‐ray measurements to produce the first in situ measurement of hydrogen concentrations on an asteroid. The measured value, ppm, is consistent with hydrogen concentrations measured in L andLLchondrite meteorite falls. Gamma‐ray derived abundances of hydrogen and potassium show no evidence for depletion of volatiles relative to ordinary chondrites, suggesting that the sulfur depletion observed in X‐ray data is a surficial effect, consistent with a space‐weathering origin. The newfound agreement between the X‐ray, gamma‐ray, and spectral data suggests that theNEARlanding site, a ponded regolith deposit, has an elemental composition that is indistinguishable from the mean surface. This observation argues against a pond formation process that segregates metals from silicates, and instead suggests that the differences observed in reflectance spectra between the ponds and bulk Eros are due to grain size differences resulting from granular sorting of ponded material.
The Corynebacterium glutamicum mycothiol peroxidase is a reactive oxygen species‐scavenging enzyme that shows promiscuity in thiol redox control
Authors: Pedre Brandán , Van Molle Inge , Villadangos Almudena F. , Wahni Khadija , Vertommen Didier , Turell Lucía , Erdogan Huriye , Mateos Luis M. , Messens Joris 
Published: March 2015

SummaryCysteine glutathione peroxidases (CysGPxs) control oxidative stress levels by reducing hydroperoxides at the expense of cysteine thiol (‐SH) oxidation, and the recovery of their peroxidatic activity is generally accomplished by thioredoxin (Trx). Corynebacterium glutamicum mycothiol peroxidase (Mpx) is a member of the CysGPx family. We discovered that its recycling is controlled by both the Trx and the mycothiol (MSH) pathway. After H2O2 reduction, a sulfenic acid (‐SOH) is formed on the peroxidatic cysteine (Cys36), which then reacts with the resolving cysteine (Cys79), forming an intramolecular disulfide (S‐S), which is reduced by Trx. Alternatively, the sulfenic acid reacts with MSH and forms a mixed disulfide. Mycoredoxin 1 (Mrx1) reduces the mixed disulfide, in which Mrx1 acts in combination with MSH and mycothiol disulfide reductase as a biological relevant monothiol reducing system. Remarkably, Trx can also take over the role of Mrx1 and reduce the Mpx‐MSH mixed disulfide using a dithiol mechanism. Furthermore, Mpx is important for cellular survival under H2O2 stress, and its gene expression is clearly induced upon H2O2 challenge. These findings add a new dimension to the redox control and the functioning of CysGPxs in general.
What plant hydraulics can tell us about responses to climate‐change droughts
Authors: Sperry John S. , Love David M. 
Published: March 2015

SummaryClimate change exposes vegetation to unusual drought, causing declines in productivity and increased mortality. Drought responses are hard to anticipate because canopy transpiration and diffusive conductance (G) respond to drying soil and vapor pressure deficit (D) in complex ways. A growing database of hydraulic traits, combined with a parsimonious theory of tree water transport and its regulation, may improve predictions of at‐risk vegetation. The theory uses the physics of flow through soil and xylem to quantify how canopy water supply declines with drought and ceases by hydraulic failure. This transpiration ‘supply function’ is used to predict a water ‘loss function’ by assuming that stomatal regulation exploits transport capacity while avoiding failure. Supply–loss theory incorporates root distribution, hydraulic redistribution, cavitation vulnerability, and cavitation reversal. The theory efficiently defines stomatal responses to D, drying soil, and hydraulic vulnerability. Driving the theory with climate predicts drought‐induced loss of plant hydraulic conductance (k), canopy G, carbon assimilation, and productivity. Data lead to the ‘chronic stress hypothesis’ wherein > 60% loss of k increases mortality by multiple mechanisms. Supply–loss theory predicts the climatic conditions that push vegetation over this risk threshold. The theory's simplicity and predictive power encourage testing and application in large‐scale modeling.

Contents

Summary
14

I.
Introduction
14

II.
The transpiration supply function
15

III.
The transpiration loss function
17

IV.
General properties of the supply–loss theory
19

V.
Variations on the theme
19

VI.
Predicting responses to climate
21

VII.
Implications for productivity and mortality: the chronic stress hypothesis
22

VIII.
Conclusion
24

Acknowledgements
24

References
24
When do plant radiations influence community assembly? The importance of historical contingency in the race for niche space
Authors: Tanentzap Andrew J. , Brandt Angela J. , Smissen Rob D. , Heenan Peter B. , Fukami Tadashi , Lee William G. 
Published: March 2015

SummaryPlant radiations are widespread but their influence on community assembly has rarely been investigated. Theory and some evidence suggest that radiations can allow lineages to monopolize niche space when founding species arrive early into new bioclimatic regions and exploit ecological opportunities. These early radiations may subsequently reduce niche availability and dampen diversification of later arrivals.We tested this hypothesis of time‐dependent lineage diversification and community dominance using the alpine flora of New Zealand. We estimated ages of 16 genera from published phylogenies and determined their relative occurrence across climatic and physical gradients in the alpine zone. We used these data to reconstruct occupancy of environmental space through time, integrating palaeoclimatic and palaeogeological changes.Our analysis suggested that earlier‐colonizing lineages encountered a greater availability of environmental space, which promoted greater species diversity and occupancy of niche space. Genera that occupied broader niches were subsequently more dominant in local communities. An earlier time of arrival also contributed to greater diversity independently of its influence in accessing niche space.We suggest that plant radiations influence community assembly when they arise early in the occupancy of environmental space, allowing them to exclude later‐arriving colonists from ecological communities by niche preemption.
Parallel effects of temperature on the male cricket calling song, phonotaxis of the female and the auditory responses of the L3 neurone
Authors: Navia Benjamin , Burden Christina , Steely Tori , Hasegawa Helen , Cha Esther , Henson Shandelle M. , Stout John , Atkins Gordon 
Published: March 2015

AbstractSender–receiver coupling is a fundamental aspect of sexual communication systems, especially when the signal must travel over significant distances. In the cricket Acheta domesticus L., both the syllable period of the calling songs of males and the syllable periods that are most attractive to females are negatively correlated with temperature. However, the range of syllable periods that females respond to phonotactically extends beyond the range of males' calling songs at all temperatures tested. In habitats occupied by crickets, surface temperatures of the ground vary considerably. The cricket's body temperature changes rather quickly based on the amount of direct solar radiation encountered (7 °C in 1 min). The responses by females to calling songs with syllable periods outside of the males' range might be advantageous in countering the effects of local variations in temperature caused by variations in the microhabitat. A temperature shift in the response to syllable period of the L3 auditory neurone parallels the temperature shift seen in the phonotactic response over a similar temperature range. These similarities support the model of the involvement of L3 in the phonotactic response and its modulation by temperature.
Automated Fish Detection in Underwater Images Using Shape‐Based Level Sets
Authors: Ravanbakhsh Mehdi , Shortis Mark R. , Shafait Faisal , Mian Ajmal , Harvey Euan S. , Seager James W. 
Published: March 2015

AbstractUnderwater stereo‐video systems are widely used for the measurement of fish. However, the effectiveness of stereo‐video measurement has been limited because most operational systems still rely on a human operator. In this paper an automated approach for fish detection, using a shape‐based level‐sets framework, is presented. Knowledge of the shape of fish is modelled by principal component analysis (PCA). The Haar classifier is used for precise localisation of the fish head and snout in the image, which is vital information for close‐proximity initialisation of the shape model. The approach has been tested on underwater images representing a variety of challenging situations typical of the underwater environment, such as background interference and poor contrast boundaries. The results obtained demonstrate that the approach is capable of overcoming these difficulties and capturing the fish outline to sub‐pixel accuracy.
Introduction to the Special Issue: Globalisation, Knowledge and Institutional Change: Towards an Evolutionary Perspective to Economic Development
Authors: Morrison Andrea , Cusmano Lucia 
Published: March 2015

AbstractThis special issue aims at advancing the debate about the interpretative power of evolutionary perspectives on economic development and institutional change. In the introduction, we argue that the interpretative power of the current evolutionary approach can be improved by elaborating an ‘augmented’ perspective to economic development, which explicitly integrates the role of institutions and the dynamics of natural resource sectors (e.g. agro‐food) into the analysis. We maintain that such a theoretical and empirical advancement can help to define a conceptual framework that is more suitable to analyse innovation‐driven change, differentiated development patterns, opportunities and constraints for developing countries in the globalised knowledge economy. A collection of papers that adopt this perspective are discussed in order to prove the interpretative power of this approach in a variety of development contexts.
An analysis of first‐time blood donors return behaviour using regression models
Authors: Kheiri S. , Alibeigi Z. 
Published: March 2015

SUMMARYBackground and ObjectivesBlood products have a vital role in saving many patients' lives. The aim of this study was to analyse blood donor return behaviour.Materials and MethodsUsing a cross‐sectional follow‐up design of 5‐year duration, 864 first‐time donors who had donated blood were selected using a systematic sampling. The behaviours of donors via three response variables, return to donation, frequency of return to donation and the time interval between donations, were analysed based on logistic regression, negative binomial regression and Cox's shared frailty model for recurrent events respectively.ResultsSuccessful return to donation rated at 49·1% and the deferral rate was 13·3%. There was a significant reverse relationship between the frequency of return to donation and the time interval between donations. Sex, body weight and job had an effect on return to donation; weight and frequency of donation during the first year had a direct effect on the total frequency of donations. Age, weight and job had a significant effect on the time intervals between donations.ConclusionAging decreases the chances of return to donation and increases the time interval between donations. Body weight affects the three response variables, i.e. the higher the weight, the more the chances of return to donation and the shorter the time interval between donations. There is a positive correlation between the frequency of donations in the first year and the total number of return to donations. Also, the shorter the time interval between donations is, the higher the frequency of donations.
The CO2 concentrating mechanism and photosynthetic carbon assimilation in limiting CO2: how Chlamydomonas works against the gradient
Authors: Wang Yingjun , Stessman Dan J. , Spalding Martin H. 
Published: March 2015

SummaryThe CO2 concentrating mechanism (CCM) represents an effective strategy for carbon acquisition that enables microalgae to survive and proliferate when the CO2 concentration limits photosynthesis. The CCM improves photosynthetic performance by raising the CO2 concentration at the site of ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco), simultaneously enhancing carbon fixation and suppressing photorespiration. Active inorganic carbon (Ci) uptake, Rubisco sequestration and interconversion between different Ci species catalyzed by carbonic anhydrases (CAs) are key components in the CCM, and an array of molecular regulatory elements is present to facilitate the sensing of CO2 availability, to regulate the expression of the CCM and to coordinate interplay between photosynthetic carbon metabolism and other metabolic processes in response to limiting CO2 conditions. This review intends to integrate our current understanding of the eukaryotic algal CCM and its interaction with carbon assimilation, based largely on Chlamydomonas as a model, and to illustrate how Chlamydomonas acclimates to limiting CO2 conditions and how its CCM is regulated.
Na+ channel function, regulation, structure, trafficking and sequestration
Authors: Chen‐Izu Ye , Shaw Robin M. , Pitt Geoffrey S. , Yarov‐Yarovoy Vladimir , Sack Jon T. , Abriel Hugues , Aldrich Richard W. , Belardinelli Luiz , Cannell Mark B. , Catterall William A. , Chazin Walter J. , Chiamvimonvat Nipavan , Deschenes Isabelle , Grandi Eleonora , Hund Thomas J. , Izu Leighton T. , Maier Lars S. , Maltsev Victor A. , Marionneau Celine , Mohler Peter J. , Rajamani Sridharan , Rasmusson Randall L. , Sobie Eric A. , Clancy Colleen E. , Bers Donald M. 
Published: March 2015

AbstractThis paper is the second of a series of three reviews published in this issue resulting from the University of California Davis Cardiovascular Symposium 2014: Systems approach to understanding cardiac excitation–contraction coupling and arrhythmias: Na+ channel and Na+ transport. The goal of the symposium was to bring together experts in the field to discuss points of consensus and controversy on the topic of sodium in the heart. The present review focuses on Na+ channel function and regulation, Na+ channel structure and function, and Na+ channel trafficking, sequestration and complexing.
Design of a Reconfiguration Mechanism for an Electric Stair-Climbing Wheelchair
Authors: Quaglia Giuseppe , Franco Walter , Nisi Matteo 
Published: March 2015

In this paper is described a new solution for a stair-climbing wheelchair: a device that allows disabled people to autonomously overcome architectural barriers. The paper presents the evolution of a project introduced in previous works. The aim is to obtain a wheelchair able to move both in structured and unstructured environments and overcome single steps or an entire staircase.
The innovative aspect of this work is the introduction of a hybrid solution, with a locomotion system based on wheels and an idle track for the vehicle stability.
The locomotion group permits to overcome obstacles through an original architecture based on an epicycloidal transmission. The control logic manages the motors that drive independently the two degrees of freedom of the transmission and allows to switch from an advancing mode to a climbing one.
The wheelchair must be able to move in different environments, such as flat ground or stairs, which require different specifications, sometimes in contrast. For this reason the main part of the work regards the design of a reconfiguration mechanism able to prepare the wheelchair for different working conditions.
First of all the relative positions between the elements that compose the wheelchair structure in different configuration are studied in order to optimize the performances especially in terms of regularity.
Then several possible solutions for the reconfiguration mechanism are presented and qualitatively evaluated, in order to choose the one that satisfy the design specifications.
Comparison of Ball Bearing Model Performance With and Without Centrifugal and Gyroscopic Forces
Authors: Kurvinen Emil , Sopanen Jussi , Mikkola Aki 
Published: March 2015

Bearing performance significantly affects the dynamic behaviors and estimated working life of a rotating system. A common bearing type is the ball bearing, which has been under investigation in numerous published studies. The complexity of the ball bearing models described in the literature varies as models with or without the inclusion of centrifugal forces or the gyroscopic moments of the rolling elements are equally proposed. Naturally, model complexity is related to computational burden. In particular, the inclusion of centrifugal forces and gyroscopic moments significantly increases the system degrees of freedom and lengthens solution time. On the other hand, for low or moderate rotating speeds, these effects can be neglected without significant loss of accuracy.
The objective of this paper is to present guidelines for the appropriate selection of a suitable bearing model for a case study. To this end, two ball bearing models were implemented. One considers high-speed forces, and the other neglects them. Both models were used to study a single structure, and the simulation results were compared. The bearing behavior is studied at different shaft rotation speeds and the simulation results are used to determine when the model containing the centrifugal and gyroscopic forces should be used.
A Bi-Frequency Co-Linear Array Transducer for Biomedical Ultrasound Imaging
Authors: Wang Zhuochen , Li Sibo , Liu Ruibin , Geng Xuecang , Jiang Xiaoning 
Published: March 2015

Ultrasound imaging with high resolution and large field of depth has been increasingly adopted in medical diagnosis, surgery guidance and treatment assessment because of its relatively low cost, non-invasive and capability of real-time imaging. There is always a tradeoff between the resolution and depth of field in ultrasound imaging. Conventional ultrasound works at a particular frequency, with −6 dB fractional bandwidth of < 100%, limiting the resolution or field of depth in many ultrasound imaging cases.
In this paper, a bi-frequency co-linear array covering a frequency range of 5 MHz-20 MHz was investigated to meet the requirements of resolution and depth of field for a broad range of ultrasound imaging applications. As a demonstration, a 31-element bi-frequency co-linear array was designed and fabricated, followed by element characterization and real time sectorial scan (S-scan) phantom imaging using a Verasonics system.
Numerical Modeling of Wave Soldering in PCB
Authors: Arcipreste Bruno , Soares Delfim , Ribas Luis , Teixeira José Carlos 
Published: March 2015

Manufacturing of electronic boards (commonly referred as PCB) is a highly automated process that requires an accurate control of the various processing variables. Amongst the soldering processes, wave soldering is one of the most often used. In this, the various electronic components are provisionally inserted onto the PCB, and a low velocity jet of melted solder is directed to the moving board. Due to capillarity effects the solder adheres to the component/board interface and the process is completed. This methodology is most often used for small components. The adjusting of the operating parameters (solder nozzle orientation and velocity) is often carried out on a trial and error basis resulting in a time consuming process that is at odds with the increasing demand for smaller production series that the electronics industry is faced with.
In addition the number of defects (mostly from missing components that are washed away by the impacting jet) is more likely to occur when thinner substrates are used in the PCB manufacturing.
The present paper describes the application of a Computational Fluid Dynamics model to describe the interaction of the solder jet with the PCB and the integrated circuits. The model includes the conservation equations for mass, momentum and energy in a transient time frame. The jet and surrounding ambient atmosphere are modeled as two separate fluids and the interface is tracked by a VOF model. By adjusting the computational mesh refinement the interface is captured with accuracy. The drag forces occurring in the various components are computed from the pressure data field. The model allows the optimization of the wave operating parameters as a function of the component type of and its layout in the PCB.
Design for Rapid Prototyping, Manufacturing and Tooling: Guidelines
Authors: Zaragoza-Siqueiros Jorge , Medellín-Castillo Hugo I. 
Published: March 2015

The design is an important step in the development of a product or component; many important decisions affecting the final cost and manufacturability of the product are made at this stage. Therefore several design guidelines for manufacturing and assembly (DFMA), ergonomics, maintenance, standardization, against corrosion, risk minimization, recycling, among others, have been proposed in the literature. The aim of these design guidelines is to provide designers with guidance to reduce costs, manufacturing difficulties, and increase the lifetime of a product. The use of new manufacturing techniques such as rapid prototyping, manufacturing and tooling (RPM&T) are increasing in the industry to speed up the design and development of products. However, there are not design guidelines for these emerging technologies.
This paper focuses on establishing design for rapid prototyping, manufacturing and rapid tooling (DFRPM&T) guidelines. These guidelines are based on reviews and analysis of the operating principle, materials, capabilities and limitations of current commercially available RPM&T technologies. The proposed design guidelines are classified into three types: (1) design for rapid prototyping according to the geometric characteristics of the part, (2) part quality requirements, and (3) part costs and sustainability. Important features such as support structures, overhangs, rounded, knife edges, part orientation, path planning, distortion, shrinkage, warping, accuracy, stability, part post-processing, part cost and environmental resistance are considered in the proposed design for RPM&T guidelines.
Modeling and Velocity Control of A-Shape Microrobot With Adaptive Neural Network Controller
Authors: Nojoumian M. A. , Shirazi M. Jahromi , Vossoughi G. R. , Salarieh H. 
Published: March 2015

Design and control of micro robots have been one of the interesting fields in robotics in recent years. One class of these micro robots is the legged robots. Various designs of legged robots have been proposed in the literature. All designs rely on friction for locomotion. In this paper dynamic model of a planar two-legged micro robot is presented using Luger friction model, and an adaptive neural controller used to control the robot to improve robustness and velocity of the robot.
As mentioned earlier, friction plays an important role in locomotion of the legged robots. However, especially in legged micro robots, it is difficult to model the frictional force correctly since environmental disturbances like dust and changes in shape of the test bed can significantly alter its value. Therefore, one needs to design a controller that adapt to new condition and had enough robustness so one chooses neural network controller. Result show that with updating weight of neural network robot could follow desired trajectory, and with change in friction coefficient training time was low enough to update weight at each step.