bluuebunny/crossref_metadata_2025 huggingface dataset:
The Lamb wave in parabolic equation models
Authors: Gilbert Kenneth E. , Di Xiao
Published: July 2012

The inclusion of the Lamb wave (i.e., the inclusion of gravity) in two existing atmospheric parabolic equation (PE) models is discussed. The two models are based on, respectively, the Green’s function parabolic equation (GFPE) of Gilbert and Di and the split-step pade parabolic equation (SSPPE) of Collins. While the SSPPE results essentially duplicate recent research by Lingevitch et al. [J. Acoust. Soc. Am. 105, 3049–3056 (1999)], the GFPE research is novel and gives physical insight into the nature of the Lamb wave. Each of the two PE models considered has its own particular advantages and limitations. The GFPE, for example, has an explicit term for the Lamb wave so that physical insight is enhanced. However, including gravity in the GFPE requires an assumption of an exponentially stratified density, an approximation that is valid only to a height of 50–100 km. The SSPPE has the advantage of treating gravity exactly for an arbitrary density stratification. Unfortunately, separating the Lamb wave contribution from the total acoustic field is not straightforward with the SSPPE. This paper outlines the theories for the GFPE and SSPPE and presents numerical comparisons between the two models for a number of infrasound propagation scenarios. [Work supported by the U.S. Army Space and Missile Defense Command.]
Wind gusts or scattering by turbulence: Which is more important for near-ground propagation?
Authors: Wilson D. Keith
Published: July 2012

‘‘Wind gusts’’ are actually just very large scale turbulence, generally having spatial dimensions comparable to the thickness of the atmospheric boundary layer (several hundred to several thousand meters). For propagation paths smaller than the dimensions of the wind gusts it is conceptually useful to distinguish between variations in the vertical profiles of wind and temperature along the propagation path (caused by the gusts) and scattering by smaller, wavelength-scale turbulent eddies. For example, in the case of upwind propagation, the gusts can cause the boundary of a refractive shadow zone to shift in position, whereas the smaller-scale eddies are responsible for scattering sound energy into the shadow. In this paper a numerical propagation model is used to closely examine the relative roles of the gusts and smaller-scale eddies for upwind, crosswind, and downwind propagation. The strength of both the gusts and smaller-scale eddies is modeled with turbulence similarity theory. The gusts are generally most important for low frequencies (below 100 to 200 Hz), but scattering by wavelength-scale eddies dominates at higher frequencies.
Rocket launch acoustics modeling
Authors: White Michael J. , Ogg Gary M.
Published: July 2012

The exhaust of a launch vehicle is composed of a high speed jet of gases that interact with the ambient air, the launch pad and the launch structure. This interacting flow is highly turbulent and is a significant source of sound power. Noise from the rocket plume can represent a threat to sensitive components on the vehicle and to the rocket payload (e.g., satellite). Detailed measurements have been made of sound power from several scale model rockets during the lift-off phase. These measurements have been used to successfully predict the sound pressure at other points on the launch pad and on the vehicle with fairly simple relations for propagation, reflection, and diffraction of sound. Work is now underway to automate the calculations, so that designers of future rockets or launch vehicles can assess the noise load in a lift-off environment. Future plans include extension of the model for use in prediction of community noise. [Work supported by NASA and AFRL.]
Acoustic variability and perceived foreign accent
Authors: Carmichael Lesley
Published: July 2012

Most people who learn a second language (L2) in late adolescence or adulthood retain some degree of foreign accent. This study investigates whether measurable intrafactor variability in the speech signal correlates with subjective ratings of degree of foreign accentedness, and whether there is an allowable deviation from native speaker norms corresponding to ratings of ‘‘little’’ or ‘‘no’’ accent. Native Korean speakers with varying degrees of English L2 proficiency and native English controls provided the stimuli. Tokens each contained one of three differences between Korean and English phonologies, potentially creating opportunities for accented speech: English contrasts between [l] and [ɹ]; between tense and lax vowels; and the presence of consonant clusters. Monolingual native English respondents indicated the degree of foreign accent they perceived. The stimuli recordings were subjected to acoustic analysis. Intrafactor variability measurements correlated with subjective perceptions of degree of foreign accent, implying that listeners are sensitive to specific, measurable variances in the acoustic signal. Consonant cluster avoidance correlated strongly with perceptions of foreign accent, followed by [1]-[ɹ] distance, and then vowel quality. Together with the measurement data, the ratings indicate that native listeners accept ranges of acoustic performance for different degrees of accentedness.
Variability in human judgments of foreign accent strength
Authors: Precoda Kristin
Published: July 2012

Speech recognition-based measures of foreign accent strength have been shown to correlate well with human judgments. However, some automatic measures vary noticeably, while the variability of human judgments is generally unknown. This study examined variability in human ratings of foreign accent strength within speakers. Seventy-six Japanese adults with varying English pronunciation skills read an average of 65 sentences. Eleven native speakers of American English rated the utterances for foreign accent strength using a five-point anchored scale. Listeners were selected partly for their abilities both to use the full scale and to give consistent repeated ratings. To measure categorical variability, the entropy of each speaker’s ratings by each listener was calculated. The mean equivalent number of equally likely categories was 2.6; entropy and the speaker’s average rating were strongly related. This could be due to speaker characteristics (poor speakers may vary more) or to properties of the scale (the extremes may show a floor/ceiling effect). When the effect of average rating is removed, the mean equivalent number of equally likely categories falls to 1.3. Small significant correlations remain between entropy from pairs of listeners, reflecting some agreement as to which speakers vary more given their overall level of proficiency.
Degree of foreign accent in native Japanese speakers trained in non-native phonetic contrast discrimination
Authors: Conley Ryan J. , Doeleman Tobey L. , Kuhl Patricia K. , Stevens Erica B.
Published: July 2012

Degree of foreign accent was evaluated in nine native Japanese speakers who participated in a behavioral training program to increase accuracy of perception of a non-native consonantal contrast. For all subjects, speech samples were collected after perceptual training. Additional pretraining samples were also collected from a subset of subjects. Subjects were asked to produce six sentences describing a set of visual images portraying people and objects. Images were chosen to elicit production of /r/ and /l/ sounds in different vowel context and word positions. Sentences produced by two native American English speakers were also recorded. A group of ten native American English speakers listened to digital recordings of all speakers’ sentences, randomly presented via computer, and rated them for degree of foreign accent on a seven-point scale. Each Japanese speaker’s scores were averaged and then correlated with their performance on discrimination of /r/ and /l/ before and after training, as well as with results from a functional magnetic resonance imaging study in which the same subjects participated [Doeleman et al., J. Acoust. Soc. Am. 107, 2803 (2000)]. These comparisons reveal how differences in degree of foreign accent correspond to behavioral and neuroimaging data. [Work supported by NICHD HD37954 to P.K.K.]
Perceptual assimilation and categorical discrimination of Korean stop consonants by native Thai speakers
Authors: Wayland Ratree
Published: July 2012

This study examined cross language perceptual assimilation and cross language categorical discrimination. Experiment 1 assessed the native Thai speakers’ ability to discriminate pairs of Korean stop consonants (plain, aspirated, reinforced) at three places of articulation (bilabial, alveolar, and velar). Experiment 2 assessed the perceived relation between the three classes of Korean stop consonants and the three classes of Thai stop consonants (voiced, voiceless unaspirated, voiceless aspirated). Preliminary results suggested that, in general, native Thai speakers assimilated the Korean plain and aspirated stops to the Thai aspirated stops, and the Korean reinforced stops to the Thai unaspirated stops. Results of the categorical discrimination revealed that native Thai speakers were able to successfully discriminate pairs of Korean stop consonants and that there was no relationship between their perceptual assimilation patterns and their ability to discriminate Korean stop consonants. Since the main perceptual cue to the discrimination of Thai stops is voice onset time (VOT), these results suggest that VOT is also the main perceptual cue for the discrimination of Korean stops. Moreover, laryngealization seems to play only a minor role in the perception of Korean stop consonants.
Memory’s Penumbra: Episodic Memory Decisions Induce Lingering Mnemonic Biases
Authors: Duncan Katherine , Sadanand Arhanti , Davachi Lila
Published: July 2012

New for Old?

When confronted with a visual stimulus, such as an object or a scene, the brain decides whether it is new, and thus deserves to be encoded as a new memory, or old, which triggers the retrieval of the previously encoded memory. When shown a series of stimuli, some of which are similar to, but not identical to, old memories, it becomes necessary to switch back and forth between encoding and retrieval processing. Using behavioral tasks performed by human test subjects,

Duncan
et al.

(p.
485
) took advantage of the fact that switching takes a second or two and found that a subsequent object, presented before switching has occurred, was more likely to be identified as new when the previous object was new, and identified as old when the previous object was old.
Binary Interaction Dominates the Evolution of Massive Stars
Authors: Sana H. , de Mink S. E. , de Koter A. , Langer N. , Evans C. J. , Gieles M. , Gosset E. , Izzard R. G. , Le Bouquin J.-B. , Schneider F. R. N.
Published: July 2012

Star Partners

Stars more massive than eight times the mass of the Sun are rare and short-lived, yet they are fundamentally important because they produce all the heavy elements in the universe, such as iron, silicon, and calcium.

Sana
et al.

(p.
444
) examined the properties of a sample of ∼70 massive stars in six stellar clusters located nearby in our galaxy. Over half of the stars in the sample belong to a binary system and, during the course of their lifetimes, most of the stars in these binaries will interact with one another, either by merging or exchanging mass. Binary interaction may thus affect the evolution of the majority of massive stars.
U.S.'s Best Science and Math Teachers to Get Bonuses
Authors: Mervis Jeffrey
Published: July 2012

The U.S. Department of Education is launching a $100 million program to pay select science and math teachers more money to reward excellence in the classroom.
Insulin May Guarantee the Honesty of Beetle's Massive Horn
Authors: Pennisi Elizabeth
Published: July 2012

Work presented at the meeting shows that the nature of the developmental pathway that leads to sexually selected traits related to size may be what makes these traits reflect health and stature.
Hip pads reduce the overall risk of injuries in recreational snowboarders
Authors: Ishimaru Daichi , Ogawa Hiroyasu , Wakahara Kazuhiko , Sumi Hiroshi , Sumi Yasuhiko , Shimizu Katsuji
Published: July 2012

Objective

The purpose is to determine common injuries in recreational snowboarding as targets of preventive strategy and protective gear that reduces the overall risk of these injuries.

Methods

The subjects comprised 5561 injured recreational snowboarders. On the basis of patients’ self-reporting form, ‘the common snowboarding injuries’ (cut-off point >2.0% in prevalence) were decided, and all injured snowboarders were categorised into two groups: common injuries and the other injuries (control). Several factors such as age, gender, self-reported skill level, experienced seasons, experienced days, previous snowboarding school attendance and the use of protective gears (helmet, elbow pads, wrist guards, backbone guard, hip pads and knee pads) were recorded. Multiple logistic regression analysis was conducted to investigate which type of protective gear reduced the overall risk of the common injuries.

Results

The common snowboarding injuries consisted of eight types, in which distal radial fracture was the most common (17.7%), followed by head injury (9.4%) and clavicle fracture (6.5%). In univariate regression analysis, skill level, experienced seasons, experienced days and the use of hip pads and knee pads were manifested potential risk factors on the common injuries. In subsequent multivariate regression analysis, the use of hip pads was related with a lower overall risk of these common injuries (OR, 0.84; 95% CI, 0.75 to 0.95), specifically that of distal radial fracture and glenohumeral dislocation.

Conclusions

The use of hip pads is recommended for snowboarders as it reduces the overall risk of common snowboarding injuries.
Health risk for athletes at moderate altitude and normobaric hypoxia
Authors: Schommer Kai , Menold Elmar , Subudhi Andrew W , Bärtsch Peter
Published: July 2012

Altitudes at which athletes compete or train do usually not exceed 2000–2500 m. At these moderate altitudes acute mountain sickness (AMS) is mild, transient and affects at the most 25% of a tourist population at risk. Unpublished data included in this review paper demonstrate that more intense physical activity associated with high-altitude training or mountaineering does not increase prevalence or severity of AMS at these altitudes. These conclusions can also be extended to the use of normobaric hypoxia, as data in this paper suggest that the severity of AMS is not significantly different between hypobaric and normobaric hypoxia at the same ambient pO2. Furthermore, high-altitude cerebral or pulmonary oedema do not occur at these altitudes and intermittent exposure to considerably higher altitudes (4000–6000 m) used by athletes for hypoxic training are too short to cause acute high-altitude illnesses. Even moderate altitude between 2000 and 3000 m can, however, exacerbate cardiovascular or pulmonary disease or lead to a first manifestation of undiagnosed illness in older people that may belong to the accompanying staff of athletes. Moderate altitudes may also lead to splenic infarctions in healthy athletes with sickle cell trait.
Endovascular therapy yields significantly superior outcomes for large vessel occlusions compared with intravenous thrombolysis: is it time to randomize?
Authors: Rai Ansaar T , Carpenter Jeffrey S , Raghuram Karthikram , Roberts Thomas D , Rodgers Daniel , Hobbs Gerald R
Published: July 2012

Background and purpose

We compared outcomes between endovascular (EV) therapy and intravenous (IV) thrombolysis in large vessel strokes.

Methods

223 patients who had received either IV (n=100) or EV (n=123) therapy were analyzed. Only patients with strokes involving the internal carotid artery terminus (ICA-T, n=45), the middle cerebral artery (M1, n=107) or the bifurcation branches (M2, n=71) were included. The primary endpoint was 3 month outcome based on the modified Rankin Scale (mRS) score, good-outcome defined as mRS ≤2.

Results

The good outcome was 44.7% in the EV group and 26% in the IV group (p=0.003, OR 2.3, 95% CI 1.3 to 4.1). There was no difference in mortality or hemorrhage. For ICA-T occlusions, the good outcome was 27.6% in the EV and 0% in the IV group (p=0.004); for M1 occlusions, 40.6% in the EV versus 10.5% in the IV group (p=0.0006, OR 5.8, 95% CI 1.9 to 18.2); and for M2 occlusions, 76% in the EV versus 47.8% in the IV group (p=0.01, OR 3.5, 95% CI 1.2 to 10.2). For M1 occlusions, the death rate was 27.5% for the EV compared with 57.9% for the IV group (p=0.002, OR 3.6, 95% CI 1.6 to 8.3) with no difference observed in mortality for ICA-T or M2 occlusions. In the univariate analysis, age, National Institutes of Health Stroke Scale score and occlusion site were significant predictors of outcome and mortality (p<0.0001 for all). In the multivariable analysis, EV therapy (p=0.0004, OR 3.9, 95% CI 1.8 to 9) and younger age (p<0.0001, OR 0.96, 95% CI 0.9 to 0.98) were significant independent predictors of good outcome.

Conclusions

There are significantly higher odds of a favorable outcome with EV compared with IV therapy for large vessel strokes. The data support the rationale of a randomized trial for large vessel occlusions.
Testing nilpotence of galois groups in polynomial time
Authors: Arvind V. , Kurur Piyush P.
Published: July 2012

We give the first polynomial-time algorithm for checking whether the Galois group Gal(
f
) of an input polynomial
f
(
X
) ∈ Q[
X
] is nilpotent: the running time of our algorithm is bounded by a polynomial in the size of the coefficients of
f
and the degree of
f
. Additionally, we give a deterministic polynomial-time algorithm that, when given as input a polynomial
f
(
X
) ∈ Q[
X
] with nilpotent Galois group, computes for each prime factor
p
of # Gal(
f
), a polynomial

g
p

(
X
)∈ Q[
X
] whose Galois group of is the
p
-Sylow subgroup of Gal(
f
).
On modeling of coevolution of strategies and structure in autonomous overlay networks
Authors: Wang Yufeng , Nakao Akihiro , Vasilakos Athanasios V.
Published: July 2012

Currently, on one hand, there exist much work about network formation and/or growth models, and on the other hand, cooperative strategy evolutions are extensively investigated in biological, economic, and social systems. Generally, overlay networks are heterogeneous, dynamic, and distributed environments managed by multiple administrative authorities, shared by users with different and competing interests, or even autonomously provided by independent and rational users. Thus, the structure of a whole overlay network and the peers' rational strategies are ever coevolving. However, there are very few approaches that theoretically investigate the coevolution between network structure and individual rational behaviors. The main motivation of our article lies in that: Unlike existing work which empirically illustrates the interaction between rational strategies and network structure (through simulations), based on EGT (Evolutionary Game Theory), we not only infer a condition that could favor the cooperative strategy over defect strategy, but also theoretically characterizes the structural properties of the formed network. Specifically, our contributions are twofold. First, we strictly derive the critical benefit-to-cost ratio (b/c) that would facilitate the evolution of cooperation. The critical ratio depends on the network structure (the number of peers in system and the average degree of each peer), and the evolutionary rule (the strategy and linking mutation probabilities). Then, according to the evolutionary rules, we formally derive the structural properties of the formed network in full cooperative state. Especially, the degree distribution is compatible with the power-law, and the exponent is (4-3v)/(1-3v), wherevis peer's linking mutation probability. Furthermore, we show that, without being harmful to cooperation evolution, a slight change of the evolutionary rule will evolve the network into a small-world structure (high global efficiency and average clustering coefficient), with the same power-law degree distribution as in the original evolution model.
Choosing partners based on availability in P2P networks
Authors: Blond Stevens Le , Fessant Fabrice Le , Merrer Erwan Le
Published: July 2012

Availability of applications or devices is known to be one of the most critical variables impacting the performances of software systems. We study in this article the problem of finding peers matching a given availability pattern in a peer-to-peer (P2P) system. Motivated by practical examples, we specify two formal problems of availability matching that arise in real applications:
disconnection matching
, where peers look for partners expected to disconnect at the same time, and
presence matching
, where peers look for partners expected to be online simultaneously in the future. As a scalable and inexpensive solution, we propose to use epidemic protocols for topology management; we provide corresponding metrics for both matching problems. We evaluated this solution by simulating two P2P applications,
task scheduling
and
file storage
, over a new trace of the eDonkey network, the largest one with availability information. We first proved the existence of regularity patterns in the sessions of 14M peers over 27 days. We also showed that, using only 7 days of history, a simple predictor could select predictable peers and successfully predicted their online periods for the next week. Finally, simulations showed that our simple solution provided good partners fast enough to match the needs of both applications, and that consequently, these applications performed as efficiently at a much lower cost. This solution is purely distributed as it does not rely on any central server or oracle to operate. We believe that this work will be useful for many P2P applications for which it has been shown that choosing good partners, based on their availability, drastically improves their performance and stability.
The ethics of software engineering should be an ethics for the client
Authors: McBride Neil
Published: July 2012

Viewing software engineering as a communicative art in which client engagement is essential.
Active movement restores veridical event-timing after tactile adaptation
Authors: Tomassini Alice , Gori Monica , Burr David , Sandini Giulio , Morrone Maria Concetta
Published: July 2012

Growing evidence suggests that time in the subsecond range is tightly linked to sensory processing. Event-time can be distorted by sensory adaptation, and many temporal illusions can accompany action execution. In this study, we show that adaptation to tactile motion causes a strong contraction of the apparent duration of tactile stimuli. However, when subjects make a voluntary motor act before judging the duration, it annuls the adaptation-induced temporal distortion, reestablishing veridical event-time. The movement needs to be performed actively by the subject: passive movement of similar magnitude and dynamics has no effect on adaptation, showing that it is the motor commands themselves, rather than reafferent signals from body movement, which reset the adaptation for tactile duration. No other concomitant perceptual changes were reported (such as apparent speed or enhanced temporal discrimination), ruling out a generalized effect of body movement on somatosensory processing. We suggest that active movement resets timing mechanisms in preparation for the new scenario that the movement will cause, eliminating inappropriate biases in perceived time. Our brain seems to utilize the intention-to-move signals to retune its perceptual machinery appropriately, to prepare to extract new temporal information.
Molecular identity, ontogeny, and cAMP modulation of the hyperpolarization-activated current in vestibular ganglion neurons
Authors: Almanza Angélica , Luis Enoch , Mercado Francisco , Vega Rosario , Soto Enrique
Published: July 2012

Properties, developmental regulation, and cAMP modulation of the hyperpolarization-activated current ( Ih) were investigated by the whole cell patch-clamp technique in vestibular ganglion neurons of the rat at two postnatal stages (P7–10 and P25–28). In addition, by RT-PCR and immunohistochemistry the identity and distribution of hyperpolarization-activated and cyclic nucleotide-gated channel (HCN) isoforms that generate Ih were investigated. Ih current density was larger in P25–28 than P7–10 rats, increasing 410% for small cells (<30 pF) and 200% for larger cells (>30 pF). The half-maximum activation voltage ( V1/2) of Ih was −102 mV in P7–10 rats and in P25–28 rats shifted 7 mV toward positive voltages. At both ages, intracellular cAMP increased Ih current density, decreased its activation time constant (τ), and resulted in a rightward shift of V1/2 by 9 mV. Perfusion of 8-BrcAMP increased Ih amplitude and speed up its activation kinetics. Ih was blocked by Cs+, zatebradine, and ZD7288. As expected, these drugs also reduced the voltage sag caused with hyperpolarizing pulses and prevented the postpulse action potential generation without changes in the resting potential. RT-PCR analysis showed that HCN1 and HCN2 subunits were predominantly amplified in vestibular ganglia and end organs and HCN3 and HCN4 to a lesser extent. Immunohistochemistry showed that the four HCN subunits were differentially expressed (HCN1 > HCN2 > HCN3 ≥ HCN4) in ganglion slices and in cultured neurons at both P7–10 and P25–28 stages. Developmental changes shifted V1/2 of Ih closer to the resting membrane potential, increasing its functional role. Modulation of Ih by cAMP-mediated signaling pathway constitutes a potentially relevant control mechanism for the modulation of afferent neuron discharge.
On the Second-Order Statistics of Correlated Cascaded Rayleigh Fading Channels
Authors: Chau Yawgeng A. , Huang Karl Y.-T.
Published: July 2012

The second-order statistics of two correlated cascaded (double) Rayleigh fading channels are analyzed, where different relevant second-order cross-correlation functions of in-phase and quadrature components of the cascaded Rayleigh channels are derived. The level crossing rate (LCR) and average fade duration (AFD) of the cascaded channels are evaluated, and a single-integral form of the LCR is derived. Numerical results of the LCR and AFD are presented, and the effect of the correlation is illustrated.
Accounting for Antenna in Half-Space Fresnel Coefficient Estimation
Authors: D'Alterio A. , Solimene R.
Published: July 2012

The problem of retrieving the Fresnel reflection coefficients of a half-space medium starting from measurements collected under a reflection mode multistatic configuration is dealt with. According to our previous results, reflection coefficient estimation is cast as the inversion of linear operator. However, here, we take a step ahead towards more realistic scenarios as the role of antennas (both transmitting and receiving) is embodied in the estimation procedure. Numerical results are presented to show the effectiveness of the method for different types of half-space media.
Partial Extinction, Permanence, and Global Attractivity in Nonautonomous n‐Species Gilpin‐Ayala Competitive Systems with Impulses
Authors: Hou Juan , Liu Hanhui
Published: July 2012

The qualitative properties of general nonautonomous n‐species Gilpin‐Ayala competitive systems with impulsive effects are studied. Some new criteria on the permanence, extinction, and global attractivity of partial species are established by using the methods of inequalities estimate and Liapunov functions.
Fracture Toughness of Vinyl Ester Composites Reinforced with Sawdust and Postcured in Microwaves
Authors: Ku H. , Prajapati M. , Trada M.
Published: July 2012

A commercial vinyl ester resin supplied by Hetron Chemical Pty. was reinforced with varying percentages by weight of sawdust. The sawdust particles were sieved into 3 different sizes, which were <300 μm, 300–425 μm, and 425–1180 μm, respectively, with a view to increase its fracture toughness for civil and structural applications. The sawdust used varied from 0% w/t to 15% w/t in step of 5% w/t. For higher w/t% of sawdust, the mixture would be too sticky to be mixed and cast. The cast composites were cured in ambient conditions and then postcured in microwave irradiation. They were then tested for fracture toughness using short bar tests. The values of fracture toughness of the composites increased with increasing particulate size, and this is due to the size distribution of the filler. It was found that the optimum amount of sawdust (425–1180 μm) was 15% w/t, with which the increase in fracture toughness was 126% as compared to neat resin and the reduction in cost was 15%. Furthermore, the optimum amount of sawdust (300–425 μm) was also 15% w/t, with which the increase in fracture toughness was 28.3% as compared to neat resin and the reduction in cost was again 15%.
Percutaneous Iliac Screws for Minimally Invasive Spinal Deformity Surgery
Authors: Wang Michael Y.
Published: July 2012

Introduction. Adult spinal deformity (ASD) surgeries carry significant morbidity, and this has led many surgeons to apply minimally invasive surgery (MIS) techniques to reduce the blood loss, infections, and other peri-operative complications. A spectrum of techniques for MIS correction of ASD has thus evolved, most recently the application of percutaneous iliac screws.Methods. Over an 18 months 10 patients with thoracolumbar scoliosis underwent MIS surgery. The mean age was 73 years (70% females). Patients were treated with multi-level facet osteotomies and interbody fusion using expandable cages followed by percutaneous screw fixation. Percutaneous iliac screws were placed bilaterally using the obturator outlet view to target the ischial body.Results. All patients were successfully instrumented without conversion to an open technique. Mean operative time was 302 minutes and the mean blood loss was 480 cc, with no intraoperative complications. A total of 20 screws were placed successfully as judged by CT scanning to confirm no bony violations. Complications included: two asymptomatic medial breaches at T10 and L5, and one patient requiring delayed epidural hematoma evacuation.Conclusions. Percutaneous iliac screws can be placed safely in patients with ASD. This MIS technique allows for successful caudal anchoring to stress-shield the sacrum and L5-S1 fusion site in long-segment constructs.
Solving the Tractor and Semi‐Trailer Routing Problem Based on a Heuristic Approach
Authors: Li Hongqi , Lu Yue , Zhang Jun , Wang Tianyi
Published: July 2012

We study the tractor and semi‐trailer routing problem (TSRP), a variant of the vehicle routing problem (VRP). In the TSRP model for this paper, vehicles are dispatched on a trailer‐flow network where there is only one main depot, and all tractors originate and terminate in the main depot. Two types of decisions are involved: the number of tractors and the route of each tractor. Heuristic algorithms have seen widespread application to various extensions of the VRP. However, this approach has not been applied to the TSRP. We propose a heuristic algorithm to solve the TSRP. The proposed heuristic algorithm first constructs the initial route set by the limitation of a driver’s on‐duty time. The candidate routes in the initial set are then filtered by a two‐phase approach. The computational study shows that our algorithm is feasible for the TSRP. Moreover, the algorithm takes relatively little time to obtain satisfactory solutions. The results suggest that our heuristic algorithm is competitive in solving the TSRP.
Multistrand, Fast Reaction, Shape Memory Alloy System for Uninhabited Aerial Vehicle Flight Control
Authors: Brennison M. , Barrett R. M. , Kerth L.
Published: July 2012

This paper details an investigation of shape memory alloy (SMA) filaments which are used to drive a flight control system with precision control in a real flight environment. An antagonistic SMA actuator was developed with an integrated demodulator circuit from a JR NES 911 subscale UAV actuator. Most SMA actuator studies concentrate on modeling the open-loop characteristics of such a system with full actuator performance modeling. This paper is a bit different in that it is very practically oriented and centered on development of a flight-capable system which solves the most tricky, practical problems associated with using SMA filaments for aircraft flight control. By using well-tuned feedback loops, it is shown that intermediate SMA performance prediction is not appropriate for flight control system (FCS) design. Rather, capturing the peak behavior is far more important, along with appropriate feedback loop design. To prove the system, an SMA actuator was designed and installed in the fuselage of a 2 m uninhabited aerial vehicle (UAV) and used to control the rudder through slips and coordinated turns. The actuator was capable of 20 degrees of positive and negative deflection and was capable of 7.5 in-oz (5.29 N cm) of torque at a bandwidth of 2.8 Hz.
Body Mass Index and Hospital Mortality in Patients with Acute Coronary Syndrome Receiving Care in a University Hospital
Authors: Camprubi Mercedes , Cabrera Sandra , Sans Jordi , Vidal Georgina , Salvadó Teresa , Bardají Alfredo
Published: July 2012

Although obesity is a well-established cardiovascular risk factor, some controversy has arisen with regard to its effect on hospital mortality in patients admitted for acute coronary syndrome.Methods. Clinical and anthropometric variables were analyzed in patients consecutively admitted for acute coronary syndrome to a university hospital between 2009 and 2010, and the correlation of those variables with hospital mortality was examined.Results. A total of 824 patients with a diagnosis of myocardial infarction or unstable angina were analyzed. Body mass index was an independent factor in hospital mortality (odds ratio 0.739 (IC 95%:0.597-0.916),P=0.006). Mortality in normal weight(n=218), overweight(n=399), and obese(n=172)subjects was 6.1%, 3.1%, and 4.1%, respectively, with no statistically significant differences between the groups.Conclusions. There is something of a paradox in the relationship between body mass index and hospital mortality in patients with acute coronary syndrome in that the mortality rate decreases as body mass index increases. However, no statistically significant differences have been found in normal weight, overweight, or obese subjects.
Numerical Simulation of Axion Quintessence
Authors: Gardner Carl L.
Published: July 2012

Robust, scaled cosmological equations are derived for simulating the evolution of the scalar field, the scale factor, and the Hubble parameter during both expanding and contracting phases of the universe. These scaled equations are applied to both stable (always expanding universe) and unstable axion quintessence (expanding and then collapsing universe). When applied to unstable axion quintessence, these scaled equations allow the simulations presented here to proceed much closer to the singularity at the end of a collapsing universe than any previous simulations.
Genetic Influences on Physiological and Subjective Responses to an Aerobic Exercise Session among Sedentary Adults
Authors: Karoly Hollis C. , Stevens Courtney J. , Magnan Renee E. , Harlaar Nicole , Hutchison Kent E. , Bryan Angela D.
Published: July 2012

Objective. To determine whether genetic variants suggested by the literature to be associated with physiology and fitness phenotypes predicted differential physiological and subjective responses to a bout of aerobic exercise among inactive but otherwise healthy adults.Method. Participants completed a 30-minute submaximal aerobic exercise session. Measures of physiological and subjective responding were taken before, during, and after exercise. 14 single nucleotide polymorphisms (SNPs) that have been previously associated with various exercise phenotypes were tested for associations with physiological and subjective response to exercise phenotypes.Results. We found that two SNPs in theFTOgene (rs8044769 and rs3751812) were related to positive affect change during exercise. Two SNPs in theCREB1gene (rs2253206 and 2360969) were related to change in temperature during exercise and with maximal oxygen capacity (VO2max). TheSLIT2SNP rs1379659 and theFAM5CSNP rs1935881 were associated with norepinephrine change during exercise. Finally, theOPRM1SNP rs1799971 was related to changes in norepinephrine, lactate, and rate of perceived exertion (RPE) during exercise.Conclusion. Genetic factors influence both physiological and subjective responses to exercise. A better understanding of genetic factors underlying physiological and subjective responses to aerobic exercise has implications for development and potential tailoring of exercise interventions.
Social and Behavioural Factors in Cetacean Responses to Overexploitation: Are Odontocetes Less “Resilient” Than Mysticetes?
Authors: Wade Paul R. , Reeves Randall R. , Mesnick Sarah L.
Published: July 2012

Many severely depleted populations of baleen whales (Mysticeti) have exhibited clear signs of recovery whereas there are few examples in toothed whales (Odontoceti). We hypothesize that this difference is due, at least in part, to social and behavioural factors. Clearly, a part of the lack of resilience to exploitation is explained by odontocete life history. However, an additional factor may be the highly social nature of many odontocetes in which survival and reproductive success may depend on: (a) social cohesion and organization, (b) mutual defence against predators and possible alloparental care, (c) inter-generational transfer of “knowledge”, and (d) leadership by older individuals. We found little evidence of strong recovery in any of the depleted populations examined. Their relatively low potential rates of increase mean that odontocete populations can be over-exploited with take rates of only a few percent per year. Exploitation can have effects beyond the dynamics of individual removals. Four species showed evidence of a decrease in birth rates following exploitation; potential mechanisms include a deficit of adult females, a deficit of adult males, and disruption of mating systems. The evidence for a lack of strong recovery in heavily exploited odontocete populations indicates that management should be more precautionary.
Effect of Exercise on Kidney Function, Oxidative Stress, and Inflammation in Type 2 Diabetic KK-AyMice
Authors: Ishikawa Yuji , Gohda Tomohito , Tanimoto Mitsuo , Omote Keisuke , Furukawa Masako , Yamaguchi Saori , Murakoshi Maki , Hagiwara Shinji , Horikoshi Satoshi , Funabiki Kazuhiko , Tomino Yasuhiko
Published: July 2012

Exercise is recommended for the management of type 2 diabetes, but its effects on diabetic nephropathy (DN) are still unknown. We hypothesized that appropriate exercise improves early DN via attenuation of inflammation and oxidative damage. Type 2 diabetic KK-Aymice, a spontaneous DN model, underwent two different kinds of exercise (i.e., moderate and low intensity). Sedentary mice or those undergoing an exercise regimen causing no significant body weight loss were used. We examined the urinary excretion of albumin, number of podocytes and macrophages, renal expressions of HIF-1αand MCP-1, and biomarkers of oxidative stress such as urinary 8-OHdG and serum SOD. Exercise reduced urinary levels of albumin and also maintained the number of podocytes in the exercised KK-Aymice independently of improvements of overweight and hyperglycemia, although moderate-intensity exercise increased expression of HIF-1α. Sedentary KK-Aymice showed increased expression of MCP-1 and infiltration of macrophage, increased urinary 8-OhdG, and decreased serum SOD levels compared with exercised KK-Aymice. On the whole, low-intensity exercise attenuates progression of early DN without affecting marked renal ischemia. Reduction rates of urinary albumin and maintained podocyte numbers, with parallel improvements in oxidative damage and inflammation, are related to beneficial effects of exercise in diabetic kidney disease.
Offset‐Free Strategy by Double‐Layered Linear Model Predictive Control
Authors: Zou Tao
Published: July 2012

In the real applications, the model predictive control (MPC) technology is separated into two layers, that is, a layer of conventional dynamic controller, based on which is an added layer of steady‐state target calculation. In the literature, conditions for offset‐free linear model predictive control are given for combined estimator (for both the artificial disturbance and system state), steady‐state target calculation, and dynamic controller. Usually, the offset‐free property of the double‐layered MPC is obtained under the assumption that the system is asymptotically stable. This paper considers the dynamic stability property of the double‐layered MPC.
Model of Mass and Heat Transfer during Vacuum Freeze‐Drying for Cornea
Authors: Huifen Zou , Sheng Ye , Dexi Wang , Huixing Li , Xiaozhen Cao , Lijun Yan
Published: July 2012

Cornea is the important apparatus of organism, which has complex cell structure. Heat and mass transfer and thermal parameters during vacuum freeze‐drying of keeping corneal activity are studied. The freeze‐drying cornea experiments were operated in the homemade vacuum freeze dryer. Pressure of the freeze‐drying box was about 50 Pa and temperature was about −10°C by controlled, and operating like this could guarantee survival ratio of the corneal endothelium over the grafting normal. Theory analyzing of corneal freeze‐drying, mathematical model of describing heat and mass transfer during vacuum freeze‐drying of cornea was established. The analogy computation for the freeze‐drying of cornea was made by using finite‐element computational software. When pressure of the freeze‐drying box was about 50 Pa and temperature was about −10°C, time of double‐side drying was 170 min. In this paper, a moving‐grid finite‐element method was used. The sublimation interface was tracked continuously. The finite‐element mesh is moved continuously such that the interface position always coincides with an element node. Computational precision was guaranteed. The computational results were agreed with the experimental results. It proved that the mathematical model was reasonable. The finite‐element software is adapted for calculating the heat and mass transfer of corneal freeze‐drying.
Factor VIIa: on its own and loving it
Authors: Monroe Dougald M.
Published: July 2012

In this issue of Blood, Shibeko et al have used a variety of experimental studies and mathematical models to investigate the mechanism of action of high-dose factor VIIa as a bypassing agent in hemophilia.1
Insertion of a myc-tag within α-dystroglycan domains improves its biochemical and microscopic detection
Authors: Morlacchi Simona , Sciandra Francesca , Bigotti Maria Giulia , Bozzi Manuela , Hübner Wolfgang , Galtieri Antonio , Giardina Bruno , Brancaccio Andrea
Published: July 2012

Background

Epitope tags and fluorescent fusion proteins have become indispensable molecular tools for studies in the fields of biochemistry and cell biology. The knowledge collected on the subdomain organization of the two subunits of the adhesion complex dystroglycan (DG) enabled us to insert the 10 amino acids myc-tag at different locations along the α-subunit, in order to better visualize and investigate the DG complex in eukaryotic cells.

Results

We have generated two forms of DG polypeptides via the insertion of the myc-tag 1) within a flexible loop (between a.a. 170 and 171) that separates two autonomous subdomains, and 2) within the C-terminal domain in position 500. Their analysis showed that double-tagging (the β-subunit is linked to GFP) does not significantly interfere with the correct processing of the DG precursor (pre-DG) and confirmed that the α-DG N-terminal domain is processed in the cell before α-DG reaches its plasma membrane localization. In addition, myc insertion in position 500, right before the second Ig-like domain of α-DG, proved to be an efficient tool for the detection and pulling-down of glycosylated α-DG molecules targeted at the membrane.

Conclusions

Further characterization of these and other myc-permissive site(s) will represent a valid support for the study of the maturation process of pre-DG and could result in the creation of a new class of intrinsic doubly-fluorescent DG molecules that would allow the monitoring of the two DG subunits, or of pre-DG, in cells without the need of antibodies.
Karyotype variation is indicative of subgenomic and ecotypic differentiation in switchgrass
Authors: Young Hugh A , Sarath Gautam , Tobias Christian M
Published: July 2012

Background

Karyotypes can provide information about taxonomic relationships, genetic aberrations, and the evolutionary origins of species. However, differentiation of the tiny chromosomes of switchgrass (Panicum virgatum L.) and creation of a standard karyotype for this bioenergy crop has not been accomplished due to lack of distinguishing features and polyploidy.

Results

A cytogenetic study was conducted on a dihaploid individual (2n = 2X = 18) of switchgrass to establish a chromosome karyotype. Size differences, condensation patterns, and arm-length ratios were used as identifying features and fluorescence in-situ hybridization (FISH) assigned 5S and 45S rDNA loci to chromosomes 7 and 2 respectively. Both a maize CentC and a native switchgrass centromeric repeat (PviCentC) that shared 73% sequence identity demonstrated a strong signal on chromosome 3. However, only the PviCentC probe labeled the centromeres of all chromosomes. Unexpected PviCentC and 5S rDNA hybidization patterns were consistent with severe reduction or total deletion of these repeats in one subgenome. These patterns were maintained in tetraploid and octoploid individuals. The 45S rDNA repeat produced the expected number of loci in dihaploid, tetraploid and octoploid individuals. Differences observed at the 5S rDNA loci between the upland and lowland ecotypes of switchgrass provided a basis for distinguishing these subpopulations.

Conclusion

Collectively, these results provide a quantitative karyotype of switchgrass chromosomes. FISH analyses indicate genetic divergence between subgenomes and allow for the classification of switchgrass plants belonging to divergent genetic pools. Furthermore, the karyotype structure and cytogenetic analysis of switchgrass provides a framework for future genetic and genomic studies.