bluuebunny/crossref_metadata_2025_split huggingface dataset:
Controllability of intense-laser ion acceleration
Authors: Kawata Shigeo , Nagashima Toshihiro , Takano Masahiro , Izumiyama Takeshi , Kamiyama Daiki , Barada Daisuke , Kong Qing , Gu Yan Jun , Wang Ping Xiao , Ma Yan Yun , Wang Wei Ming , Zhang Wu , Xie Jiang , Zhang Huiran , Dai Dongbo 
Published: April 2014

AbstractAn ion beam has the unique feature of being able to deposit its main energy inside a human body to kill cancer cells or inside material. However, conventional ion accelerators tend to be huge in size and cost. In this paper, a future intense-laser ion accelerator is discussed to make the laser-based ion accelerator compact and controllable. The issues in the laser ion accelerator include the energy efficiency from the laser to the ions, the ion beam collimation, the ion energy spectrum control, the ion beam bunching, and the ion particle energy control. In the study, each component is designed to control the ion beam quality by particle simulations. The energy efficiency from the laser to ions is improved by using a solid target with a fine sub-wavelength structure or a near-critical-density gas plasma. The ion beam collimation is performed by holes behind the solid target or a multi-layered solid target. The control of the ion energy spectrum and the ion particle energy, and the ion beam bunching are successfully realized by a multi-stage laser–target interaction.
Effects of target pre-heating and expansion on terahertz radiation production from intense laser-solid interactions
Authors: Yuan X.H. , Fang Y. , Carroll D.C. , MacLellan D.A. , Du F. , Booth N. , Burza M. , Chen M. , Gray R.J. , Jin Y.F. , Li Y.T. , Liu Y. , Neely D. , Powell H. , Scott G. , Wahlström C.-G. , Zhang J. , McKenna P. , Sheng Z.M. 
Published: April 2014

AbstractThe first experimental measurements of intense (${\sim }7\times 10^{19}~ {\rm W}~ {\rm cm}^{-2}$) laser-driven terahertz (THz) radiation from a solid target which is preheated by an intense pulse of laser-accelerated protons is reported. The total energy of the THz radiation is found to decrease by approximately a factor of 2 compared to a cold target reference. This is attributed to an increase in the scale length of the preformed plasma, driven by proton heating, at the front surface of the target, where the THz radiation is generated. The results show the importance of controlling the preplasma scale length for THz production.
How strain and spin may make a star bi-polar
Authors: Forbes Lawrence K. 
Published: April 2014

AbstractA previous study by Forbes (ANZIAM J., vol. 53, 2011, pp. 87–121) has argued that, when a light fluid is injected from a point source into a heavier ambient fluid, the interface between them is most unstable to perturbations at the lowest spherical mode. This means that, regardless of initial conditions, the outflow from a point source eventually becomes a one-sided jet. However, two-sided (bi-polar) outflows are nevertheless often observed in astrophysics, in apparent contradiction to this prediction. While there are many possible explanations for this fact, the present paper considers the effect of a straining flow in the ambient fluid. In addition, solid-body rotation in the inner fluid is also accounted for, in a Boussinesq viscous model. It is shown analytically that there are circumstances under which straining flow alone is sufficient to convert the one-sided jet into a genuine bi-polar outflow, in linearized theory. This is confirmed in a numerical solution of a viscous model of the flow, based on a spectral solution technique that accounts for nonlinear effects. Rotation can also generate flows that are two-sided, and this is likewise revealed through an asymptotic analysis and numerical solutions of the nonlinear equations.
THE HISTORIOGRAPHY OF ISLAM IN WEST AFRICA: AN ANTHROPOLOGIST'S VIEW
Authors: Soares Benjamin 
Published: April 2014

AbstractIn this article, I focus on the historiography of Islam in West Africa while also reflecting upon and assessing existing scholarship in the broader field of the study of Islam in Africa. My position as an anthropologist who conducts historical research informs my perspective in evaluating the current state of the field and my suggestions for directions in which I think future research might move in order to advance our understanding of Islam and Muslim societies and the history of religious life in Africa more generally.
PAWNSHIP, DEBT, AND ‘FREEDOM’ IN ATLANTIC AFRICA DURING THE ERA OF THE SLAVE TRADE: A REASSESSMENT
Authors: Lovejoy Paul E. 
Published: April 2014

AbstractA reassessment of the institution of pawnship in Africa for the period from the seventeenth century to the nineteenth century tightens the reference to situations in which individuals were held as collateral for debts that had been incurred by others, usually relatives. Contrary to the assumptions of some scholars, pawnship was not related to poverty and enslavement for debt but rather to commercial liquidity and the mechanisms by which funds were acquired to promote trade or to cover the expenses of funerals, weddings, and religious obligations. A distinction is made, therefore, between enslavement for debt and pawnship. It is demonstrated that pawnship characterized trade with European and American ships in many parts of Atlantic Africa, but not everywhere. While pawnship was common north of the Congo River, at Gabon, Cameroon, Calabar, the interior of the Bights of Biafra and Benin, the Gold Coast, and the upper Guinea coast, it was illegal in most of Muslim Africa and the Portuguese colony of Angola, while it was not used in commercial dealings with Europeans at Bonny, Ouidah, and other places.
Anomalous climatic conditions during winter 2010–2011 and vulnerability of the traditional Inuit food system in Iqaluit, Nunavut
Authors: Statham Sara , Ford James , Berrang-Ford Lea , Lardeau Marie-Pierre , Gough William , Siewierski Rick 
Published: April 2014

ABSTRACTThis study examines how climatic extremes during winter 2010–2011 affected the traditional food system in Iqaluit, Nunavut. This winter was anomalous throughout the Canadian Arctic, and manifested itself locally by warmer temperatures and decreased ice coverage. Drawing upon in-depth interviews with hunters (n = 25), a fixed question survey with public housing residents (n = 100), as well as analysis of remotely sensed sea-ice charts and temperature data from the Iqaluit weather station, this work identifies and characterises the extreme climatic conditions experienced, their subsequent effects on Iqaluit's traditional food system, and coping strategies used for dealing with food-related stresses. The results show increased environmental stress on the traditional food system compared to previous years. Freeze up occurred 59 days later than the average for the 1982–2010 period, while mean annual temperatures were 4.9ºC higher than the climatological mean, which negatively impacted hunters’ harvests and residents’ food supplies. Coping strategies alleviated some stresses, but adaptability was limited for financially insecure households reliant on income support. The study shows that when challenging socioeconomic conditions, such as those associated with public housing, are coupled with significant environmental stress, such as experienced during that winter, the vulnerability of the traditional food system is exacerbated. We suggest that winter 2010–2011 can be used as an analogue for exploring future food system vulnerabilities, with climate models projecting similar conditions in the coming decades.
Control of a compass gait walker based on energy regulation using ankle push-off and foot placement
Authors: Bhounsule Pranav A. 
Published: April 2014

SUMMARYIn this paper, we present a theoretical study on the control of a compass gait walker using energy regulation between steps. We use a return map to relate the mid-stance robot kinetic energy between steps with two control inputs, namely, foot placement and ankle push-off. We show that by regulating robot kinetic energy between steps using the two control inputs, we are able to (1) generate a wide range of walking speeds and stride lengths, including average human walking; (2) cancel the effect of external disturbance fully in a single step (dead-beat control); and (3) switch from one periodic gait to another in a single step. We hope that insights from this control methodology can help develop robust controllers for practical bipedal robots.
Cross-coupled PID control in position domain for contour tracking
Authors: Ouyang P. R. , Dam T. , Pano V. 
Published: April 2014

SUMMARYAccurate contour tracking is one of the main tasks in modern manufacturing processes. By considering coupling effects among multiple axes, this paper proposes a cross-coupled proportional-integral-derivative (PID) control developed in position domain, and the controller is applied to a multi-axis computer numerical control (CNC) machine for contour tracking performance improvement. Stability analysis is conducted for the developed position domain cross-coupled PID control using the Lyapunov method, and guidelines for the selection of control gains are provided. The contour tracking performance are improved compared to an equivalent time domain controller, since the reference axis in position domain control does not contribute any error to the overall contouring error of the system. Simulation results demonstrate the effectiveness of cross-coupled PID position domain control for both linear and circular contour tracking, and prove the robustness of the controller to deal with random disturbances. It also shows that position domain cross-coupled PID control provides better contour tracking performance over position domain PID control and the equivalent time domain PID control.
Reuse of constraint knowledge bases and problem solvers explored in engineering design
Authors: Gray Peter M.D. , Runcie Trevor , Sleeman Derek 
Published: April 2014

AbstractReuse has long been a major goal of the knowledge engineering community. We present a case study of the reuse of constraint knowledge acquired for one problem solver, by two further problem solvers. For our analysis, we chose a well-known benchmark knowledge base (KB) system written in CLIPS, which was based on the propose and revise problem-solving method and which had a lift/elevator KB. The KB contained four components, including constraints and data tables, expressed in an ontology that reflects the propose and revise task structure. Sufficient trial data was extracted manually to demonstrate the approach on two alternative problem solvers: a spreadsheet (Excel) and a constraint logic solver (ECLiPSe). The next phase was to implement ExtrAKTor, which automated the process for the whole KB. Each KB that is processed results in a working system that is able to solve the corresponding configuration task (and not only for elevators). This is in contrast to earlier work, which produced abstract formulations of the problem-solving methods but which were unable to perform reuse of actual KBs. We subsequently used the ECLiPSe solver on some more demanding vertical transport configuration tasks. We found that we had to use a little-known propagation technique described by Le Provost and Wallace (1991). Further, our techniques did not use any heuristic “fix”’ information, yet we successfully dealt with a “thrashing” problem that had been a key issue in the original vertical transit work. Consequently, we believe we have developed a widely usable approach for solving this class of parametric design problem, by applying novel constraint-based problem solvers to data and formulae stored in existing KBs.
SERPENTS, SKELETONS, AND ANCESTORS?: THE TULA COATEPANTLI REVISITED
Authors: Jordan Keith 
Published: April 2014

AbstractSince Acosta's work in the 1940s, relief carvings of serpents entwined with partially skeletonized personages on the coatepantli at Tula have frequently been identified as images of the Nahua Venus deity, Tlahuizcalpantecuhtli. Comparing these Toltec sculptures with this deity's iconography in Late Postclassic to Colonial period manuscripts, however, provides no support for this identification. Based on the northern Mesoamerican cultural connections of the Toltecs, the author suggests parallels between the coatepantli reliefs and the public display of ancestral and sacrificial human remains at Chalchihuites sites. Identification of the coatepantli figures as venerated ancestors from an ancestral cult is also supported by iconographic and archaeological evidence from Tula. Parallels to the coatepantli images in depictions of both living elites and ancestors juxtaposed with serpents from other Mesoamerican art traditions bolster this interpretation. On the basis of the evidence, the author hypothesizes that the skeletonized figures at Tula symbolize deceased kings and honored warriors rather than conquered foes.
FORTRESS MAYAPAN: DEFENSIVE FEATURES AND SECONDARY FUNCTIONS OF A POSTCLASSIC MAYA FORTIFICATION
Authors: Russell Bradley W. 
Published: April 2014

AbstractOne of the most distinctive features of the Postclassic capital of Mayapan is the immense wall that encloses large portions of the site's settlement zone. This 9.1 km-long feature is the largest example of a walled enclosure known in Mesoamerica. Based on ethnohistoric references, it seems that the construction was well known to Postclassic and Colonial period residents of the Northern lowlands. The most common assertion regarding the enclosures is that the wall had primarily defensive functions. Unfortunately, little solid archaeological evidence or cross-cultural comparison has been offered to support this interpretation. In this paper, I correlate the form of the gates with cross-culturally derived and unambiguously defensive features, finding that the design of the gates strongly suggests that they are indeed defensive. Possible secondary functions of the wall are also explored, such as the control of people and goods entering the city, as ritual barrier, the control of internal populations and its symbolism.
CHRONOLOGY OF THE RÍO BEC SETTLEMENT AND ARCHITECTURE
Authors: Taladoire Eric , Dzul Sara , Nondédéo Philippe , Forné Mélanie 
Published: April 2014

AbstractChronology is a crucial issue given the specific settlement patterns of the Río Bec region located on the northern fringe of the Maya central lowlands. Fine-resolution chronology of the local residential occupation in its many spatial and temporal forms is one of the main proxies available to reconstruct social organization and dynamics, in the absence of a nucleated center with the typical Maya political monuments usually investigated. Variability can be traced in residential morphologies and evolution that must be dated. The scope of the paper aims to describe the construction of the Río Bec chronology in its multiple dimensions, based on a diversity of methods from ceramic Type-Variety classification up to seriation of building sequences defining the evolution of the famous Río Bec architectural style. Epigraphic evidence exists, albeit limited and ambiguous. The general sequence of occupation for the targeted micro-region stretches from the Middle Preclassic to the end of the Terminal Classic period.
ASH, DIRT, AND ROCK: BURIAL PRACTICES AT RÍO BEC
Authors: Pereira Grégory 
Published: April 2014

AbstractRecent research at Río Bec has revealed that interments in residential structures were limited to a very small portion of the population. Although these burials are relatively modest compared to those found in many other Classic period Maya sites, the funerary procedure suggests that they were important individuals in the household. Grave wealth and the size/elaboration of the burial structure do not correlate with the striking socioeconomic differences expressed in residential architecture. In fact, it seems that Río Bec funerary ritual was a private affair focused within the domestic unit, rather than a public display. A study of the variation found among these residential burials reveals two important patterns of mortuary ritual that seem more reflective of ancestor veneration than of social hierarchy: (1) “transition burials” (stressing centrality,verticality,the link to earth, and the transformations of the dwelling) and (2) “occupation burials” (stressing laterality,horizontality,a link to fire and the domestic hearth, and the permanence of the domestic space).
Have population declines in Egyptian Vulture and Red-headed Vulture in India slowed since the 2006 ban on veterinary diclofenac?
Authors: GALLIGAN TOBY H. , AMANO TATSUYA , PRAKASH VIBHU M. , KULKARNI MANDAR , SHRINGARPURE ROHAN , PRAKASH NIKITA , RANADE SACHIN , GREEN RHYS E. , CUTHBERT RICHARD J. 
Published: April 2014

SummaryPopulations of three vulture species of the genus Gyps, the Egyptian Vulture Neophron percnopterus and Red-headed Vulture Sarcogyps calvus have declined markedly on the Indian subcontinent since the mid-1990s and all are now Critically Endangered or Endangered. Gyps vultures have been killed by the widely used non-steroidal anti-inflammatory drug diclofenac, ingested when they feed on carcasses of domesticated ungulates treated with the drug shortly before death. However, it is not known whether Egyptian Vulture and Red-headed Vulture are also sensitive to diclofenac. Veterinary use of diclofenac was banned in India in 2006. Since then, the prevalence and concentration of diclofenac in domesticated ungulates carcasses has decreased and population declines of Gyps vultures have slowed or reversed. Here, we examine counts of Egyptian and Red-headed Vultures obtained on road transects in and near protected areas between 1992 and 2011. We found indications that the declines in both species appear to have slowed and possibly increased after the ban was introduced, though the small numbers of birds counted make this conclusion less robust than that for the Gyps species. These results suggest that both species may have been adversely impacted by diclofenac and that government bans on this drug, which are beginning to take effect, may benefit a wider range of vulture species in the Indian subcontinent than was previously thought.
Improving the quality of acute inpatient care
Authors: Lelliott Paul , Bleksley Sarah 
Published: April 2014

AbstractOver the past ten years, the National Health Service in England has introduced home treatment teams throughout the country. Despite this, and the fact that England now has the fourth lowest number of beds per capita in Europe, no mental health service has been able to dispense with acute admission beds altogether. One unintended consequence of new investment in community alternatives to inpatient care is that the threshold for admission has risen and acute wards now accommodate a patient group that is more severe with regard to levels of disturbance and social disadvantage. This has compounded the challenge of providing high quality inpatient care and repeated national surveys suggest that acute admission wards are the weakest link in the English mental healthcare system. In response to this, the Royal College of Psychiatrists has established an accreditation scheme for acute admission wards. Only 22 of the first 132 wards to have completed the review process so far are considered to be excellent. Although 59 wards (45% of the total) failed to meet one or more essential standard, 43 of these were able to rectify the problem.Declaration of Interest: None.
Mapping Chemical Disorder and Ferroelectric Distortions in the Double Perovskite Compound Sr2-xGdxMnTiO6 by Atomic Resolution Electron Microscopy and Spectroscopy
Authors: Biškup Neven , Álvarez-Serrano Inmaculada , Veiga Maria , Rivera-Calzada Alberto , Garcia-Hernandez Mar , Pennycook Stephen J. , Varela Maria 
Published: April 2014

AbstractIn this work we report a study of the chemical and structural order of the double perovskite compound Sr2-xGdxMnTiO6 for compositions x=0, 0.25, 0.5, 0.75, and 1. A noticeable disorder at the B-site in the Mn and Ti sublattice is detected at the atomic scale by electron energy-loss spectroscopy for all x values, resulting in Mn-rich and Ti-rich regions. For x≥0.75, the cubic unit cell doubles and lowers its symmetry because of structural rearrangements associated with a giant ferroelectric displacement of the perovskite B-site cation. We discuss this finding in the light of the large electroresistance observed in Sr2-xGdxMnTiO6, x≥0.75.
Evading the strength–ductility trade-off dilemma in steel through gradient hierarchical nanotwins
Authors: Wei Yujie , Li Yongqiang , Zhu Lianchun , Liu Yao , Lei Xianqi , Wang Gang , Wu Yanxin , Mi Zhenli , Liu Jiabin , Wang Hongtao , Gao Huajian 
Published: April 2014

AbstractThe strength–ductility trade-off has been a long-standing dilemma in materials science. This has limited the potential of many structural materials, steels in particular. Here we report a way of enhancing the strength of twinning-induced plasticity steel at no ductility trade-off. After applying torsion to cylindrical twinning-induced plasticity steel samples to generate a gradient nanotwinned structure along the radial direction, we find that the yielding strength of the material can be doubled at no reduction in ductility. It is shown that this evasion of strength–ductility trade-off is due to the formation of a gradient hierarchical nanotwinned structure during pre-torsion and subsequent tensile deformation. A series of finite element simulations based on crystal plasticity are performed to understand why the gradient twin structure can cause strengthening and ductility retention, and how sequential torsion and tension lead to the observed hierarchical nanotwinned structure through activation of different twinning systems.
Enforcement of γδ-lineage commitment by the pre–T-cell receptor in precursors with weak γδ-TCR signals
Authors: Zarin Payam , Wong Gladys W. , Mohtashami Mahmood , Wiest David L. , Zúñiga-Pflücker Juan Carlos 
Published: April 2014

SignificanceExpression of a productively rearranged T-cell receptor (TCR)-β chain induces a program of αβ T-lineage differentiation, whereas thymocytes that productively rearranged TCR-γ and TCR-δ typically give rise to γδ-lineage T cells. However, given that all three TCR gene loci simultaneously undergo gene rearrangements, the possibility exists that a developing thymocyte may express a γδ-TCR together with a TCR-β or pre-TCR complex, and it is not clear to what this outcome would give rise in terms of T-lineage differentiation. Our findings point to a striking conclusion, in that rather than transmitting signals that exclusively promote αβ-lineage commitment/differentiation, the pre-TCR can function in concert with the γδ-TCR to promote γδ commitment/differentiation, a result that supports a signal strength model of αβ/γδ-lineage choice.
T helper 17 cells play a critical pathogenic role in lung cancer
Authors: Chang Seon Hee , Mirabolfathinejad Seyedeh Golsar , Katta Harshadadevi , Cumpian Amber M. , Gong Lei , Caetano Mauricio S. , Moghaddam Seyed Javad , Dong Chen 
Published: April 2014

Significance
One of the challenging problems in lung cancer is to understand how inflammation pathways influence on the development of lung cancer and to identify early immune mediators. In this study, we functionally dissect the critical events occurring at the interface between endogenously arising lung tumors and the host immune system that determine tumor progression. Our findings greatly advance our knowledge on the function of T helper 17 cells in lung cancer and help understand the mechanisms of inflammatory mediators that promote lung cancer.