bluuebunny/crossref_metadata_2025 huggingface dataset:
Food webs and the sustainability of indiscriminate fisheries
Authors: McCann Kevin S. , Gellner Gabriel , McMeans Bailey C. , Deenik Tina , Holtgrieve Gordon , Rooney Neil , Hannah Lee , Cooperman Michael , Nam So
Published: October 2015

Here, we introduce a novel theory for multispecies fisheries that exploit fish stocks evenly within and across trophic levels in an entire ecosystem (i.e., fishery comprises all fleets). These “indiscriminate” fisheries may be common in developing countries where fish provide the main source of dietary protein. We show that simple food web modules, motivated by empirical patterns in body size and energy flow, yield general and robust predictions about the fate of such a fishery. Specifically, high and uniform fishing mortality modifies the fish community in a manner that leads to increased productive capacity from a low-diversity assemblage of small-bodied fish with rapid population growth and turnover (the productive monoculture effect). We then argue that catches are relatively indiscriminate in the Tonlé Sap, a highly productive inland fishery in Cambodia that feeds millions, and show consistent qualitative agreement between the theory of indiscriminate fishing and this existing empirical data. As the theory suggests, this indiscriminate fishery appears to be remarkably productive at the community level in the face of high fishing mortality; however, it tends to be unsustainable at the species level as the Tonlé Sap has a much depleted species diversity under its current high fishing mortality. We end by arguing that the reduced diversity of these types of fisheries likely put them at severe risk of being heavily impacted by changing environmental conditions such as climate change and hydroelectric development.
The quick and the dead: copepods dominate as cladocerans decline following invasion by Hemimysis anomala
Authors: Sinclair James S. , Arnott Shelley E. , Cox Amelia
Published: October 2015

The North American invasion of a non-native mysid, Hemimysis anomala, has been expanding since 2006, with the first inland lake invasions detected for Oneida Lake in 2009 and Seneca Lake in 2010. Although we know that Hemimysis primarily consumes zooplankton, our ability to predict the community-level impact of an invasion is hampered by a lack of information on taxon-specific effects. To investigate the effects of Hemimysis on native zooplankton, we conducted two mesocosm experiments that compared composition between communities with and without Hemimysis and studied how the effects of this predator on zooplankton species composition varied across a natural gradient of low to high invader densities (0.01–0.1 individuals·L−1). Our first experiment found that Hemimysis primarily affected cladocerans, and particularly Daphnia, shifting communities towards dominance by copepods. Our second experiment showed that Hemimysis invasions may do little to suppress Daphnia abundances until between 0.067–0.11 individuals·L−1 or higher. Cladocerans are important links in freshwater trophic transfer and the nutrient cycle, and disruption of these linkages following Hemimysis invasion could result in both bottom-up and top-down impacts in nearshore food webs. However, Hemimysis can also fill a similar trophic role as the zooplankton they consume, and longer-term experiments are required to better assess their eventual impacts on native communities.
Predicting harvest of non-native signal crayfish in lakes — a role for changing climate?
Authors: Bohman Patrik , Edsman Lennart , Sandström Alfred , Nyström Per , Stenberg Marika , Hertonsson Pia , Johansson Jacob
Published: October 2015

The signal crayfish (Pacifastacus leniusculus) was introduced to Sweden in 1960, and it has a high commercial and recreational value, but it may also have negative effects on native ecosystems. To better predict how climate warming will affect population dynamics of this cool-water crayfish, we explored the role of temperature and density dependence as explanatory factors of the subsequent years’ catch rates of commercially sized signal crayfish in four Swedish lakes. We found air temperatures to be good proxies for water temperatures in all lakes, except during winter. We could only obtain water temperature data for Lake Vättern, and winter temperature data were therefore only included in the analysis of catch-per-unit-effort patterns in this lake. Our results indicate that increasing mean air temperatures will potentially affect the population dynamics of cool-water freshwater crayfish species such as the signal crayfish. Based on data from four lakes, it seems that the population dynamics of signal crayfish are lake-specific and could be affected by either recruitment during the juvenile stage, the survival and growth of adults, or both. Increased fluctuations in water temperature during winter may potentially influence adult survival. To better predict the effects of global warming on the dynamics of cool-water crayfish populations, we suggest that future studies should investigate recruitment in crayfish along temperature gradients and the influence of variations in water temperature on winter mortality.
Evaluating a multi-generational reintroduction program for threatened salmon using genetic parentage analysis
Authors: Evans Melissa L. , Johnson Marc A. , Jacobson Dave , Wang Jinliang , Hogansen Michael , O’Malley Kathleen G.
Published: October 2015

Dams, utilized for hydroelectric or flood control purposes, obstruct organism dispersal and have contributed to the decline of many migratory fish populations. For threatened Chinook salmon (Oncorhynchus tshawytscha) from the Willamette River Basin in Oregon, human-assisted reintroductions are being used to facilitate dispersal to historical habitats located above dams. However, little is known about the reproductive outcomes of reintroduced individuals or the efficacy of reintroductions towards the goal of population demographic viability. Using genetic parentage assignments to 3-, 4-, and 5-year-old adult recruits, we estimated the fitness of hatchery and wild Chinook salmon reintroduced above Foster Dam on the South Santiam River, a tributary of the Willamette River. Our parentage assignments indicated that the fitness of reintroduced salmon was highly variable, with individuals producing a range of 0–40 adult progeny. We also detected a possible trend towards reduced fitness in mate pairs composed of hatchery versus wild salmon. For each of three brood years (2007, 2008, 2009), adult offspring recruitment achieved or exceeded population replacement. We observed the highest cohort replacement rate in 2009, the first year that managers aimed to release wild salmon solely above the dam. Taken together, our results suggest that human-assisted reintroductions of mature adult salmon to historical spawning habitats are a promising method of restoring natural production in populations affected by dams. Moreover, the continued used of wild fish in reintroduction operations may improve population productivity and the prospect of recovery within the South Santiam River.
Variations in bacterial communities during foliar litter decomposition in the winter and growing seasons in an alpine forest of the eastern Tibetan Plateau
Authors: Zhao Yeyi , Wu Fuzhong , Yang Wanqin , Tan Bo , He Wei
Published: October 2015

Bacterial communities are the primary engineers during litter decomposition and related material cycling, and they can be strongly controlled by seasonal changes in temperature and other environmental factors. However, limited information is available on changes in the bacterial community from winter to the growing season as litter decomposition proceeds in cold climates. Here, we investigated the abundance and structure of bacterial communities using real-time quantitative PCR and denaturing gradient gel electrophoresis (DGGE) during a 2-year field study of the decomposition of litter of 4 species in the winter and growing seasons of an alpine forest of the eastern Tibetan Plateau. The abundance of the bacterial 16S rRNA gene was relatively high during decomposition of cypress and birch litter in the first winter, but for the other litters 16S rRNA abundance during both winters was significantly lower than during the following growing season. A large number of bands were observed on the DGGE gels, and their intensities and number from the winter samples were lower than those from the growing season during the 2-year decomposition experiment. Eighty-nine sequences from the bands of bacteria that had been cut from the DGGE gels were affiliated with 10 distinct classes of bacteria and an unknown group. A redundancy analysis indicated that the moisture, mass loss, and elemental content (e.g., C, N, and P) of the litter significantly affected the bacterial communities. Collectively, the results suggest that uneven seasonal changes in climate regulate bacterial communities and other decomposers, thus affecting their contribution to litter decomposition processes in the alpine forest.
Transient Circuit Model of Memristors
Authors: Mazady Anas , Anwar Mehdi
Published: October 2015

We report a transient circuit model of Pt/TiO2(40nm)/Pt memristor that accurately represents the underlying switching mechanism and can be extended to any other material platforms. The analysis is based on the analytic formulation of dynamical characteristics. The transient circuit model is simulated in Cadence using HSPICE. Rise time and fall times of the 40 nm TiO2 memristor were calculated to be 11.4 ps and 11.6 ps, respectively. The settling time during ON and OFF switching was determined to be 1.04 ns and 0.78 ns, respectively.
Computational Nanocharacterization for Combinatorially Developed Bulk Metallic Glass
Authors: Gossett Eric M. , Scanley Ellen B. , Liu Yanhui , Li Yanglin , Liu Ze , Sohn Sungwoo , Schroers Jan , Broadbridge Christine , Schwendemann Todd C.
Published: October 2015

Bulk metallic glasses synthesized at specialized facilities at Yale using magnetron cosputtering are sent to Southern Connecticut State University for elemental characterization. Characterization is done using a Zeiss Sigma VP SEM coupled with an Oxford EDS. Characterization is automated using control software provided by Oxford. Collected data is processed and visualized using computational methods developed internally. Processed data is then organized into a database suitable for web retrieval. This technique allows for the rapid characterization of a combinatorial wafer to be carried out in ~11 hours for a single wafer containing ~600 unique compounds.
DC Circuit Model of TiO2-based Memristors
Authors: Mazady Anas , Anwar Mehdi
Published: October 2015

DC circuit model of TiO2 memristors is developed based on the reported I-V data. The method described can easily be implemented to realize memristor based circuitries that serve different application platforms fabricated using any material combination. The time varying length of conductive filaments inside memristor, responsible for the observed switching mechanism, is implemented as the state variable and the state equations are modified accordingly. Once the device physics is taken into account the circuit model can be further adapted to predict the behavior of memristor with altered dimensions.
Copper-CNT Hybrid TSVs: Thermo-Mechanical Stresses and Reliability Analysis
Authors: Ladani Leila
Published: October 2015

Through silicon vias (TSVs) play a critical role in today’s microelectronic technology as they enable fabrication of three-dimensional integrated circuits. Traditionally, copper has been used to fill TSVs. However, copper is prone to electro-migration and as the size of TSVs become smaller, copper resistance increases significantly, thereby reducing its potential for TSV material at nanoscales. A proposed hybrid structure is presented here in which Carbon Nanotube (CNT) bundles are grown vertically inside TSVs and encased with copper. The CNT bundles assists with increasing the strength of the hybrid structure and is likely to enhance the reliability of the package. Thermo-mechanical stress analysis and reliability evaluations is conducted to determine the effect of CNT bundles on stress distribution in the package and their impact on reliability of other critical components such as solder bumps that are used to join the silicon layers. The finite element analysis shows that addition of CNT material to the structure, even in small volume ratios tend to redistribute the stress and refocus it to inside the CNT material rather than interfaces. Interface stresses in low strength material typically cause delamination and failure in the package. Redistribution of stress is likely to enhance the reliability of the TSVs. Additional reliability analysis of the solder joints, shows that CNT additions enhances the number of cycles to failure four times. It is hypothesized that addition of CNTs decreases the local CTE mismatch between the silicon layers and assists in reducing the stress in solder bumps. This hypothesis is proven using finite element simulations.
ZnMgO/ZnO Core-Shell Structures for Gas Sensing
Authors: Rivera Abdiel , Mazady Anas , Anwar Mehdi
Published: October 2015

Co-axial Zn1−xMgxO core, ZnO shell structures were grown using metal organic chemical vapor deposition (MOCVD), with Mg mole fractions of 2, 5 and 10%. The co-axial core shell structure, with the respective Mg concentration is verified using scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS). The response times (ṟise time and fall time) of the devices, after being exposed to methanol, varied with Mg mole fraction at the core, r-0.17s and, f-0.37s & f-0.48s for 2% Mg, r-0.81s and, f-5.98s & f-0.89s for 5% Mg and r-0.33s and f-0.13s for 10% Mg. The sensitivity of the devices at room temperature increased with the increment of Mg mole fraction at the core, 25%, 48% and 50% with Mg concentration of 0.02, 0.05 and 0.1, respectively, under high concentration of methanol. The estimated activation energy, corresponds to doubly charged oxygen vacancy (Vo2+).
Correlated electron dynamics of nonsequential double ionization by few-cycle laser pulses with different time durations
Authors: Yu Benhai , Li Yingbin , Tang Qingbin , Hua Duanyang , Jia Shasha
Published: October 2015

With the fully classical ensemble model, we investigate the correlated electron dynamics of nonsequential double ionization (NSDI) by few-cycle laser pulses at 3T (T is the laser cycle) and compared it with the 6T case. For the 6T laser pulse, the momentum distribution of correlated electron in the direction parallel to the laser polarization exhibits a V-like structure which has been observed in the experiment. [Camus et al., Phys. Rev. Lett. 108, 073003 (2012)]. However, for the 3T laser pulse, the momentum distribution shows a surprising arc-like structure. Meanwhile, the correlated electron momentum spectrum in the direction perpendicular to the laser polarization shows a more stronger anticorrelated behavior for the 3T laser pulse than that of the 6T laser pulse. By analyzing all the classical trajectories of NSDI, for the 3T laser pulse, the contribution to NSDI only comes from the first return and the latter returns are completely supressed, which is different from the case of the 6T laser pulse where not only the first return but also the latter returns contribute to the NSDI events. Moreover, the recolliding energies are often higher for the 3T laser pulse than that of the 6T laser pulse due to a more rapid turn on of laser field for the 3T laser pulse which plays a key role for the arc-like structure. The more energetic recollisions that occur in the 3T laser pulse lead to greater anticorrelation in the transverse momenta than is observed in the 6T laser pulse with less energetic recollisions.
Plasmon mode coupling and depolarization shifts in AlGaAs/GaAs asymmetric step quantum wells with and without electric field
Authors: Song Ya Feng , Zhu Qin Sheng , Liu Xiang Lin , Yang Shao Yan , Wang Zhan Guo
Published: October 2015

We investigate the plasmon mode coupling and depolarization shifts in AlGaAs/GaAs asymmetric step quantum wells (ASQWs) of the two-subband model with the Bohm–Pine’s random-phase approximation with and without an applied electric field. By adjusting the well geometry parameters and material composition systematically, various characteristics of plasmons in ASQWs are found for different asymmetric cases. We find that (i) the intersubband plasmon has a large negative dispersion in long wavelength limit; (ii) the step width related depolarization shift depends on the number of subbands in the deep well; and (iii) the influence of electric field effect on depolarization shift and the coupling of the two plasmon modes is quite asymmetric with its minimum at +8 kV/cm by changing the electrical field and the ASQW structure parameters. The coupling and decoupling of the intersubband and intrasubband plasmon modes can be realized by adjusting the polarity and the strength of the external electric field and changing the ASQW structure parameters.
Synthesis of LaYbO3 perovskite through modified Pechini method: Structural, electric and magnetic characterization
Authors: Jaramillo P J. A. , Landínez Téllez D. A. , Roa-Rojas J. , Parra Vargas C. A. , Barrera E. W.
Published: October 2015

Single phase LaYbO3 lanthanide-based perovskite powder was synthesized by modified Pechini method, which is based on polyesterification of metal–citrate complexes in aqueous solution. Complexes were formed in aqueous solution and after polyalcohol addition and slow water evaporation, bond formation is allowed and a macroscopic polymeric network was produced, where cations are embedded and uniformly distributed. Finally, through several pyrolysis steps, microcrystalline oxide particles were obtained. Structural characterization was performed by means the powder X-ray diffraction (XRD) technique. The obtained patterns were indexed and refined to reveal that the LaYbO3 simple perovskite crystallizes in an orthorhombic structure, belonging to the Pnma (#62) space group, with lattice constants a = 6.0327 Å, b = 8.4138 Å and c = 5.8307 Å. Studies of electron dispersive X-ray spectroscopy show that the LaYbO3 is free of impurities. Electric response was evaluated by electric polarization measurements as a function of applied electric fields. Obtained curves show evidence of a hysteretic behavior related with dielectric losses which are characteristics of insulator materials. From the saturation values of electric charge, the relative dielectric constant was determined to be 22.6. The magnetic behavior was examined by means of the curves of magnetic susceptibility as a function of temperature. The fit with the Curie equation is in agreement with a typical paramagnetic feature with effective magnetic moment [Formula: see text] = 4.9 [Formula: see text]B, which is close to the theoretical expected value from the Hund’s rules.
Mapping Discovery Over Revealing Schemas
Authors: Kantere Verena , Bousounis Dimos , Sellis Timos
Published: October 2015

In a world of wide-scale information sharing, data are described in different formats, i.e. data structures, values and schemas. Querying such sources entails techniques that can bridge the data formats. Some existing techniques deal with schema mapping and view complementary aspects of the problem. Important ones, consider producing all the possible mappings for a pair of schemas, insinuating accompanying semantics in the mappings and adapting correct mappings as schemas evolve. In this work, we consider the problem of discovering mappings as schemas of autonomous sources are gradually revealed. Using as an example setting an overlay of peer databases, we present a schema mapping solution that discovers correct mappings as peer schemas are gradually revealed to remote peers. Mapping discovery is schema-centric and incorporates new semantics as they are unveiled. Mapping experience is reused and possible mappings are ranked so that the best choice is presented to the user. The experimental study confirms the suitability of the proposed solution to dynamic settings of heterogeneous sources.
Design of all-normal dispersion photonic crystal fiber for high coherent broadband supercontinuum generation in the telecommunication window
Authors: Cheng Chunfu , Ou Yiwen , Zhang Jinye , Lv Qinghua , Zhu Jinrong , Lv Hui
Published: October 2015

An all-normal dispersion photonic crystal fiber with nearly zero flattened dispersion at 1550 nm is designed for generating high coherent broadband supercontinuum. It is found that an all normal dispersion photonic crystal fiber with nearly zero flattened dispersion at 1550 nm can be obtained by appropriately designing geometrical parameters and optimizing the index of the first ring of air-holes with filling different index liquid of the photonic crystal fiber. The results show that the optimized design photonic crystal fiber for pumping at 1550 nm is suitable for flat broadband and high coherent supercontinuum generation with only 4 kW input peak power in a 40 cm long of the photonic crystal fiber. It is also found the weaker the dispersion effect is, the more advantage to the high coherent broadband supercontinuum generation due to the self-phase modulation.
Design and optimization of two dimensional photonic crystal based optical filter
Authors: Rajalakshmi G. , Sivanantha Raja A. , Shanmuga Sundar D.
Published: October 2015

In this paper, the channel drop filter based on two dimensional photonic crystal is proposed. The structure is made of silicon rods with the refractive index n1 = 3.4641 which are perforated in air with refractive index n2 = 1. The simulation results are obtained using 2D finite difference time domain (FDTD) method. The photonic band gap is calculated by plane wave expansion solver method. Resonant mode of the ring resonator and the filter transmission spectrum is calculated using 2D FDTD method. Full width half maximum (FWHM) bandwidth of the filter at the output transmission spectrum from 1.508 μm to 1.512 μm is 4 nm. The quality factor of the filter is 377.5 and the proposed filter design is around 21 × 15 μm which is suitable for photonic integrated circuits.
Two-component solitons in a chain of dimers with Parity-Time symmetric nonlinearity
Authors: Pang Wei , Chen Jun , Lv Hua
Published: October 2015

We introduced a coupled waveguide arrays with intrinsic Parity-Time (PT)-symmetric nonlinearity. The system is described by a set of coupled Schrödinger equations with linear couplings and a complex nonlinearity. Two-component soliton modes are found to exist in this system. The stability of the solitons are investigated and the stable map is plotted numerically in the parameter plane of linear coupling and the strength of PT nonlinearity. The effects of the PT nonlinearity on the amplitude and the effective area of the soliton modes are studied. It is found that the PT nonlinearity can manipulate the amplitude and the propagation constant of the soliton modes. The mobility of these soliton modes are studied numerically. The soliton modes can be kicked to move and increase the PT nonlinearity will enhance the mobility. Collision of two soliton modes are investigated and the results indicates that we can control the types and properties of the collision by adjusting the linear coupling and the PT nonlinearity.
Super and subluminal propagation in nonlinear Schrödinger equation model with self-steepening and self-frequency shift
Authors: Saini A. , Vyas V. M. , Raju Thokala Soloman , Pandey S. N. , Panigrahi Prasanta K.
Published: October 2015

We investigate exact traveling wave solutions of higher order nonlinear Schrödinger equation (NLSE) in the absence of third-order dispersion, which exhibit nontrivial self-phase modulation. It is shown that the corresponding dynamical equation, governing the evolution of intensity in the femtosecond regime, is that of NLSE with a source. The exact localized solutions to this system can have both super and subluminal propagation belonging to two distinct classes. A number of these solitons exhibit chirality, thereby showing preferential propagation behavior determined by group velocity dispersion. Both localized bright and dark solitons are found in complementary velocity and experimental parameter domains, which can exist for anomalous and normal dispersion regimes. It is found that dark solitons in this system propagate with nonzero velocity, unlike their counterpart in nanosecond regime. Interestingly, subluminal propagation is observed for solitons having a nontrivial Padé type intensity profile.
Mach–Zehnder nonlinear interferometer in photonic crystal fibers with nonlinearity profiles
Authors: Sales J. C. , Filho A. F. G. F. , Ferreira A. C. , Sousa J. R. R. , Avila K. M. V. , Cavalcante D. N. S. , Magalhães F. T. C. B. , Sobrinho C. S. , Pinto P. V. F. , Guimarães G. F. , Menezes J. W. M. , Costa D. B. , Sombra A. S. B.
Published: October 2015

In this work, we present a numerical study to investigate the transmission, extinction ratio, crosstalk and compression factor outputs of a Mach–Zehnder interferometer in photonic crystal fibers by varying the nonlinearity parameter of the fiber from β = 1 to β = 2 for three different nonlinearity profiles (constant, increasing and decreasing) and in three different scenarios (P0= Pc, P0< Pc and P0> Pc). We observed that the highest transmission (T = 67%), the highest extinction ratio (XR = 3.57 dB) and the lowest crosstalk (Xtalk = -5.25 dB) occurred in the third scenario (P0= 110 kW > Pc) considering the decreasing profile for β = 1.35. Such condition enables applications such as TDMA and logic circuits.
Single beam Z-scan for the calculation of nonlinear refractive index (n2) for poly(2,5-dimethylaniline)
Authors: Biswas M. K. , Amin M. K. , Das P. K. , Hoque E. , Sharafuddin S. M. , Younus M. , Das S. K. , Haque Y.
Published: October 2015

An experimental work has been done to measure the nonlinear refractive index of poly(2,5-dimethylaniline) (PDMA). In this work, a continuous wave (cw) Ar-ion laser has been used to calculate n2 for a novel polymer; poly(2,5-dimethylaniline): synthesized from 2,5 dimethylaniline. The single beam Z-scan technique was used with laser beams of 514 and 488 nm wavelengths, taking PDMA in methanol solvent at different concentrations. The order of n2 was found to be of the order of ~ 10-14 esu.
CEMENTLESS MIS MINI-KEEL PROSTHESIS REDUCES INTERFACE MICROMOTION VERSUS STANDARD STEMMED TIBIAL COMPONENTS
Authors: CHONG DESMOND Y. R. , HANSEN ULRICH N. , AMIS ANDREW A.
Published: October 2015

Fixation strength of the cementless knee prostheses is dependent on the initial stability of the fixation and minimal relative motion across the prosthesis–bone interface. Broad mini-keels have been developed for tibial components to allow minimally invasive knee arthroplasty, but the effect of the change in fixation design is unknown. In this study, bone–prosthesis interface micromotions of the mini-keel tibial components (consisting of two designs; one is stemless and another with a stem extension of 45[Formula: see text]mm) induced by walking and stair climbing were investigated by finite element modeling and compared with standard stemmed design. The prosthesis surface area amenable for bone ingrowth for the mini-keel tibial components (both stemmed and unstemmed) was predicted to be at least 67% larger than the standard stemmed implant, thereby reducing the risk of long-term aseptic loosening. It was also found that while different load patterns may have led to diverse predictions of the magnitude of the interface micromotions and the extent of osseointegration onto the prosthesis, the outcome of design change evaluation in cementless tibial fixations remains unchanged. The mini-keel tibial components were predicted to anchor onto the periprosthetic bone better than the standard stemmed design under all loading conditions investigated.
MODELLING THE LINK BETWEEN LEADER–MEMBER EXCHANGE AND INDIVIDUAL INNOVATION IN R&D
Authors: DENTI LEIF , HEMLIN SVEN
Published: October 2015

This study models individual characteristics, leadership, and organisational support in relationship to individual innovation in highly complex research and development (R&D) settings. The study reports on a survey of 166 R&D team members, 43 team leaders, and 10 department managers in five Swedish industrial organisations. Individual innovation was measured using four indicators (new products, new patent applications, scientific publications, and other publications) and team leaders’ ratings of innovative work behaviour. Individuals’ inclination to take personal initiative predicted individual innovation, while intrinsic motivation and leadership (conceptualised by leader–member exchange (LMX) theory) did not. A mediating effect was found whereby LMX was associated with individual innovation through the personal initiative of team members. Organisational support moderated the relationship between LMX and individual initiative. High organisational support strengthened the relationship.
Characterization of Polymeric Membranes Under Large Deformations Using Fluid-Structure Coupling
Authors: Erchiqui Fouad , Souli Mhamed , Kanit Toufik , Imad Abdellatif , Aziz Boudlal , El Moumen Ahmed
Published: October 2015

The mechanical properties of Ogden material under biaxial deformation are obtained by using the bubble inflation technique. First, pressure inside the bubble and height at the hemispheric pole are recorded during bubble inflation experiment. Thereafter, Ogden's theory of hyperelasticity is employed to define the constitutive model of flat circular thermoplastic membranes (CTPMs) and nonlinear equilibrium equations of the inflation process are solved using finite difference method with deferred corrections. As a last step, a neuronal algorithm artificial neural network (ANN) model is employed to minimize the difference between calculated and measured parameters to determine material constants for Ogden model. This technique was successfully implemented for acrylonitrile-butadiene-styrene (ABS), at typical thermoforming temperatures, 145°C. When solving for the bubble inflation, the recorded pressure is applied uniformly on the structure. During the process inflation, the pressure is not uniform inside the bubble, thus full gas dynamic equations need to be solved to get the appropriate nonuniform pressure to be applied on the structure. In order to simulate the inflation process accurately, computational fluid dynamics in a moving fluid domain as well as fluid structure interaction (FSI) algorithms need to be performed for accurate pressure prediction and fluid structure interface coupling. Fluid structure interaction solver is then required to couple the dynamic of the inflated gas to structure motion. Recent development has been performed for the simulation of gas dynamic in a moving domain using arbitrary Lagrangian Eulerian (ALE) techniques.
A Comprehensive Analysis on the Structural–Acoustic Aspects of Various Functionally Graded Plates
Authors: Chandra N. , Raja S. , Gopal K. V. N.
Published: October 2015

The vibration, sound radiation and transmission characteristics of plates with various functionally graded materials (FGM) are explored and a detailed investigation is presented on the influence of specific material properties on structural–acoustic behavior. An improved model based on a simplified first order shear deformation theory along with a near-field elemental radiator approach is used to predict the radiated acoustic field associated with a given vibration and acoustic excitation. Various ceramic materials suitable for engineering applications are considered with aluminum as the base metal. A power law is used for the volume fraction distribution of the two constitutive materials and the effective modulus is obtained using the Mori–Tanaka homogenization scheme. The structural–acoustic response of these FGM plates is presented in terms of the plate velocity, radiated sound power, sound radiation efficiency for point and uniformly distributed load cases. Increase in both vibration and acoustic response with increase in power law index is observed for the lower order modes. The vibro–acoustic metrics such as root-mean-squared plate velocity, overall sound power, frequency averaged radiation efficiency and transmission loss, are used to rank these materials for vibro–acoustically efficient combination. Detailed analysis has been made on the factors influencing the structural–acoustic behavior of various FGM plates and relative ranking of particular ceramic/metal combinations.
Politics of Translation
Authors: Gal Susan
Published: October 2015

Current research finds the label “translation” an apt characterization of diverse communicative practices. This review argues that the term points to a whole family of semiotic processes. Writings on translation share a key insight: Different social worlds—including those of scholars—emerge through forms of communication in which practices, objects, genres, and texts are citable, recontextualizable. This generative process mediates among the domains of knowledge and action that the communications themselves play a role in separating. The connections and differentiations, as framed by metadiscourses, construct relations of power and politics. I seek to highlight a widening, productive conversation about translational practices among studies of science, in medical, legal, and linguistic anthropology, in research on Christianities, and in advocacy. The translation rubric gathers together practices of transduction, (in)commensuration, circulation, enactment of reference, standardizations, and various forms of boundary making. Recent work on semiotics clarifies how such practices achieve their effects.
Health of Indigenous Peoples
Authors: Valeggia Claudia R. , Snodgrass J. Josh
Published: October 2015

Indigenous populations worldwide are experiencing social, cultural, demographic, nutritional, and psychoemotional changes that have a profound impact on health. Regardless of their geographical location or sociopolitical situation, health indicators are always poorer for indigenous populations than for nonindigenous ones. The determinants of this gap are multiple and interactive, and their analysis requires a biocultural framework. Indigenous populations suffer from lower life expectancy, high infant and child mortality, high maternal morbidity and mortality, heavy infectious disease loads, malnutrition, stunted growth, increasing levels of cardiovascular and other chronic diseases, substance abuse, and depression. The devastating effects of colonization, the loss of ancestral land, and language and cultural barriers for access to health care are among the most salient themes characterizing the poor health situation of indigenous people. Anthropology is extremely well suited to address the interplay among social, economic, and political forces that shape the local experiences of illness.
The Evolution of Difficult Childbirth and Helpless Hominin Infants
Authors: Dunsworth Holly , Eccleston Leah
Published: October 2015

Because of the implications for behavioral, social, and cultural evolution, reconstructions of the evolutionary history of human parturition are driven by two main questions: First, when did childbirth become difficult? And second, does difficult childbirth have something to do with infant helplessness? Here we review the available evidence and consider answers to these questions. Although the definitive timeframe remains unclear, childbirth may not have reached our present state of difficulty until fairly recently (<500,000 years ago) when body and brain sizes approximated what we have now, or perhaps not until even more recently because of agriculture's direct and indirect effects on the growth and development of both mother and fetus. At present, there is little evidence to indicate that difficult childbirth has affected the evolution of gestation length or fetal growth, selecting for infants that are born in a supposed underdeveloped state, although these phenomena likely share causes.
An Evolutionary and Life-History Perspective on Osteoporosis
Authors: Madimenos Felicia C.
Published: October 2015

Osteoporosis is a systemic disease characterized by bone mass reductions and heightened fracture risk; its global prevalence rates are projected to increase precipitously over the next few decades. Evolutionary and life-history perspectives have proven valuable for offering a different lens with which to consider the etiologies of common chronic diseases, and in this review, these approaches are applied to osteoporosis. Although there are many perspectives on human susceptibility to bone loss, this article explores the most prominent and empirically studied theories. Osteoporosis is considered within the context of theories on aging (e.g., antagonistic pleiotropy, disposable soma) and mismatch theory. Female vulnerability is considered within a separate evolutionary framework and has been articulated as a trade-off between reproduction and skeletal health. Recent advancements in bone imaging techniques for skeletal and living human and nonhuman primate populations (i.e., CT scans, ultrasonometry) have facilitated huge strides in contextualizing osteoporosis within evolutionary theory.
An Evolutionary Anthropological Perspective on Modern Human Origins
Authors: Marean Curtis W.
Published: October 2015

Modern humans are an anomaly in evolution, and the final key features occurred late in human evolution. Ultimate explanations for this evolutionary trajectory are best attained through synthetic studies that integrate genetics, biological anthropology, and archaeology, all resting firmly in the field of evolutionary anthropology. These fields of endeavor typically operate in relative isolation. This synthetic overview identifies the three pillars of human uniqueness: an evolved advanced cognition, hyperprosociality, and psychology for social learning. These properties are foundational for cumulative culture, the dominant adaptation of our species. Although the Homo line evolved in the direction of advancing cognition, the evidence shows that only modern humans evolved extreme levels of prosociality and social learning; this review offers an explanation. These three traits were in place ∼200–100 ka and produced a creature capable of extraordinary social and technological structures, but one that was also empowered to make war in large groups with advanced weapons. The advance out of Africa and the annihilation of other hominin taxa, and many unprepared megafauna, were assured.
Risks of Citizenship and Fault Lines of Survival
Authors: Petryna Adriana , Follis Karolina
Published: October 2015

This article probes the contradictions and unacknowledged risks inherent in the notion of citizenship today. We explore the possible fault lines that citizenship places on the notion of universality, namely the anthropology of contexts in which citizenship and biological self-preservation are being radically decoupled as well as the policies, techniques, and media (biological, health, juridical) through which such decoupling takes place. What concepts have anthropologists brought to the fore to address the emerging “fault lines of survival” embodied in the term citizenship? How have these concepts been taken up, becoming vehicles for resisting, or at least assessing, what has become of citizenship? Moving beyond narrowly conceptualized policy problems and calculations, this article also considers alternative pathways through which the “political” is being mobilized and through which a new politics of rescue appears.
Interactions Between the Gastrointestinal Microbiome and Clostridium difficile
Authors: Theriot Casey M. , Young Vincent B.
Published: October 2015

Antibiotics have significant and long-lasting effects on the intestinal microbiota and consequently reduce colonization resistance against pathogens, including Clostridium difficile. By altering the community structure of the gut microbiome, antibiotics alter the intestinal metabolome, which includes both host- and microbe-derived metabolites. The mechanisms by which antibiotics reduce colonization resistance against C. difficile are unknown yet important for development of preventative and therapeutic approaches against this pathogen. This review focuses on how antibiotics alter the structure of the gut microbiota and how this alters microbial metabolism in the intestine. Interactions between gut microbial products and C. difficile spore germination, growth, and toxin production are discussed. New bacterial therapies to restore changes in bacteria-driven intestinal metabolism following antibiotics will have important applications for treatment and prevention of C. difficile infection.
Bacterial Proteasomes
Authors: Jastrab Jordan B. , Darwin K. Heran
Published: October 2015

Interest in bacterial proteasomes was sparked by the discovery that proteasomal degradation is required for the pathogenesis of Mycobacterium tuberculosis, one of the world's deadliest pathogens. Although bacterial proteasomes are structurally similar to their eukaryotic and archaeal homologs, there are key differences in their mechanisms of assembly, activation, and substrate targeting for degradation. In this article, we compare and contrast bacterial proteasomes with their archaeal and eukaryotic counterparts, and we discuss recent advances in our understanding of how bacterial proteasomes function to influence microbial physiology.
Candida albicans Biofilms and Human Disease
Authors: Nobile Clarissa J. , Johnson Alexander D.
Published: October 2015

In humans, microbial cells (including bacteria, archaea, and fungi) greatly outnumber host cells. Candida albicans is the most prevalent fungal species of the human microbiota; this species asymptomatically colonizes many areas of the body, particularly the gastrointestinal and genitourinary tracts of healthy individuals. Alterations in host immunity, stress, resident microbiota, and other factors can lead to C. albicans overgrowth, causing a wide range of infections, from superficial mucosal to hematogenously disseminated candidiasis. To date, most studies of C. albicans have been carried out in suspension cultures; however, the medical impact of C. albicans (like that of many other microorganisms) depends on its ability to thrive as a biofilm, a closely packed community of cells. Biofilms are notorious for forming on implanted medical devices, including catheters, pacemakers, dentures, and prosthetic joints, which provide a surface and sanctuary for biofilm growth. C. albicans biofilms are intrinsically resistant to conventional antifungal therapeutics, the host immune system, and other environmental perturbations, making biofilm-based infections a significant clinical challenge. Here, we review our current knowledge of biofilms formed by C. albicans and closely related fungal species.
My Lifelong Passion for Biochemistry and Anaerobic Microorganisms
Authors: Thauer Rudolf Kurt
Published: October 2015

Early parental influence led me first to medical school, but after developing a passion for biochemistry and sensing the need for a deeper foundation, I changed to chemistry. During breaks between semesters, I worked in various biochemistry labs to acquire a feeling for the different areas of investigation. The scientific puzzle that fascinated me most was the metabolism of the anaerobic bacterium Clostridium kluyveri, which I took on in 1965 in Karl Decker's lab in Freiburg, Germany. I quickly realized that little was known about the biochemistry of strict anaerobes such as clostridia, methanogens, acetogens, and sulfate-reducing bacteria and that these were ideal model organisms to study fundamental questions of energy conservation, CO2 fixation, and the evolution of metabolic pathways. My passion for anaerobes was born then and is unabated even after 50 years of study.
Ion Regulation in the Malaria Parasite
Authors: Kirk Kiaran
Published: October 2015

Some hours after invading the erythrocytes of its human host, the malaria parasite Plasmodium falciparum induces an increase in the permeability of the erythrocyte membrane to monovalent ions. The resulting net influx of Na+ and net efflux of K+, down their respective concentration gradients, converts the erythrocyte cytosol from an initially high-K+, low-Na+ solution to a high-Na+, low-K+ solution. The intraerythrocytic parasite itself exerts tight control over its internal Na+, K+, Cl−, and Ca2+ concentrations and its intracellular pH through the combined actions of a range of membrane transport proteins. The molecular mechanisms underpinning ion regulation in the parasite are receiving increasing attention, not least because PfATP4, a P-type ATPase postulated to be involved in Na+ regulation, has emerged as a potential antimalarial drug target, susceptible to inhibition by a wide range of chemically unrelated compounds.
The Legacy of Cornell Accelerators
Authors: Tigner M. , Cassel D.G.
Published: October 2015

This is the story of a culture and its evolution and legacy. Beginning with the invention of the cyclotron at Berkeley, the path of further accelerator development at Cornell via the Los Alamos experience of the primary actors is described. The science done with the accelerators and on the accelerators and beams themselves is reviewed and brought up to the current time. The evolution of the user community and the sources of support for accelerators and science done with them are discussed at the appropriate places in the story.
Neutron Matter from Low to High Density
Authors: Gandolfi Stefano , Gezerlis Alexandros , Carlson J.
Published: October 2015

Neutron matter is an intriguing nuclear system with multiple connections to condensed matter and astrophysics. Considerable progress has been made over the past 20 years in exploring the properties of pure neutron fluids. We begin by reviewing research exploring the behavior of very low density neutron matter, which forms a strongly paired superfluid and is thus similar to cold Fermi atoms, although at energy scales that differ by many orders of magnitude. We then review the behavior of higher-density neutron matter, discussing research that ties the study of neutron matter to the determination of the properties of neutron-rich nuclei and neutron star crusts. Finally, we review the impact that neutron matter at even higher densities has on the mass–radius relation of neutron stars, thereby making contact with astrophysical observations.
New Technologies in Gravitational-Wave Detection
Authors: Ballmer Stefan , Mandic Vuk
Published: October 2015

Over the past two decades, interferometric gravitational-wave (GW) detector technology has been dramatically improved and is now reaching sensitivity levels that are generally believed to be sufficient for the first direct detection of GWs generated by astrophysical sources. Second-generation detectors are currently being commissioned and should produce the first observation data as early as this year. Upgrades and new detection techniques are also under development for third-generation detectors, which are expected to fully explore the potential of GW astrophysics. We describe the technology choices used or planned for second- and third-generation GW detectors.
Effective Field Theory and Time-Reversal Violation in Light Nuclei
Authors: Mereghetti E. , van Kolck U.
Published: October 2015

Thanks to the unnaturally small value of the QCD vacuum angle [Formula: see text], time–reversal violation ([Formula: see text]) offers a window into physics beyond the Standard Model (SM) of particle physics. We review the effective field theory framework that establishes a clean connection between (a) [Formula: see text] mechanisms, which can be represented by higher-dimensional operators involving SM fields and symmetries, and (b) hadronic interactions, which allow for controlled calculations of low-energy observables involving strong interactions. The chiral properties of [Formula: see text] mechanisms lead to a pattern that should be identifiable in measurements of the electric dipole moments of the nucleon and light nuclei.