bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic Multiprocessor Scheduling Model for the Reconfigurable Mesh Computing Networks
Authors: Salleh Shahruddin , Aziz Nur Arina Bazilah , Azmee Nor Afzalina , Mohamed Nurul Huda
Published: January 2013

Masalah penjadualan kerja ialah satu masalah pengoptimuman kombinatorik yang diketahui mempunyai darjah kebebasan berinteraksi yang besar. Oleh itu, masalah ini selalunya dikategorikan sebagai NP-lengkap. Kebanyakan penyelesaian bagi masalah ini menggunakan heuristik. Penyelesaiannya termasuk pendekatan berasaskan penjadualan tersenarai, teori giliran, teori graf dan pencaraian berenumerasi. Dalam kertas ini, satu kaedah penjadualan dinamik dicadangkan bagi memeta satu set kerja kepada satu set pemproses dalam rangkaian jaring boleh-konfigurasi. Model kami dipanggil Dynamic Scheduler on Reconfigurable Mesh (DSRM). Model ini berasaskan sistem giliran m/m/c di mana kerja-kerja yang tiba menunggu giliran masing-masing mengikut taburan Poisson, dan diservis mengikut taburan eksponen. Objektif utama dalam kajian ini ialah untuk menghasilkan jadual yang mempunyai taburan kerja seimbang pada pemproses-pemproses. Objektif kedua ialah untuk mempertingkat kadar pengagihan kerja ke tahap maksimum untuk memastikan kejayaan. Kedua-dua objektif ini merupakan satu masalah dikenali sebagai maksimum-minimum, di mana kejayaan dalam satu objektif boleh menyebabkan kemerosotan dalam objektif yang satu lagi. Keberkesanan pendekatan ini dikaji melalui model simulasi DSRM.

Kata kunci: Jaring boleh-konfigurasi; penjadualan kerja; pengseimbangan beban dan perkomputeran selari

Task scheduling is a combinatorial optimisation problem that is known to have large interacting degrees of freedom and is gerally classified as NP-complete. Most solutions to the problem have been proposed in the form of heuristics. These include approaches using list scheduling, queueing theory, graph theoretic and enumerated search. In this paper, we present a dynamic scheduling method for mapping tasks onto a set of processing elements (PEs) on the reconfigurable mesh parallel computing model. Our model called the Dynamic Scheduler on Reconfigurable Mesh (DSRM) is based on the Markovian m/m/c queueing system, where tasks arrive and form a queue according to Poisson distribution, and are serviced according to the exponential distribution. The main objective in our strudy is to produce a schedule that distributes the tasks fairly by balancing the load on all PEs. The second objective is to produce a high rate of sucessfully assigned tasks on the PEs. These two requirements tend to conflict and they constitute the maximum-minimum problem in optimisation, where the maximum of one causes the other to be minimum. We study the effectiveness of our approach in dealing with these two requirements in DSRM.

Key words: Reconfigurable mesh; task scheduling; load balancing; and parallel computing
A Generalized Form Of Integral-Finite Element Formulations For Diffusion Equation
Authors: Nawang Wan Mokhtar
Published: January 2013

A physical problem such as diffusion can be described mathematically in two ways, i.e. by Differential Equation Formulation or Integral Formulation. An integral form is derived from its governing differential equation using the method of Variational Principle for a three-dimensional heat flow equation.The equivalent Integral Formulation will be a very useful and an inevitable tool in the formulation of finite element equatipn.
A Design Program For The Linear Equalizer That Minimizes The Mean Square Error
Authors: Ashraf Mohamad
Published: January 2013

A design program with detailed illustrative example, for the linear equalizer that minimizes the mean square error due to intersymbol interference in its output signal, is presented. The results are evaluated for many types of distortion channels which have been selected from a wide range of common signal distortions.This includes the various combinations of amplitude and phase distortions.A synchroneous serial digital baseband signal is assumed throughout. The digital signal is transmitted over the linear time invariant baseband channel whose impulse response is known. The practical imple mentation of the filters and the techniques on the automatic or adaptive adjustment of the equalizer taps are not considered. The aim of the paper is to show the basic principles of the linear equalizer that minimizes the mean square error, with the aid of the design program and the example.The design of the linear equalizer is based on a statistical criterior in time domain and the study is confined to simple transversal equalizers whose tap gains do not vary except in response to a change in a channel.
A Theoretical Approach In The Analysis Of Multilayered Cross-Ply GRP Cylindrical Shell
Authors: Haji Abd. Rahman Dr. Daud
Published: January 2013

The constitutive relations for the specially orthotropic lamina under a plane stress state are employed with a linear shell theory, to obtain the governing equations for the multilayered cross-ply cylindrical shell with through thickness symmetry. The well known Fourier expansion method, used extensively in the analysis of isotropic shell problems, are extended to handle the more complex case of the anisotropic shell subject to a general loading case. Attention is confined to those loads which are symmetric with respect to the generator passing through the lowest point of the shell, that is liquid-filled, self-weight, support loading, etc.
Laminar Flow Heat Transfer and Pressure Drop in a Circular Tube Having Wire-Coil and Helical Screw-Tape Inserts
Authors: Kumar Rout Pratap , Kumar Saha Sujoy
Published: January 2013

The experimental friction factor and Nusselt number data for laminar flow through a circular duct having wire-coil and helical screw-tape inserts have been presented. Peripherally and axially local temperatures on the duct outside wall have been measured. The temperature drop across the duct wall has been calculated to obtain the duct inside wall temperatures. Peripherally averaged and axially local temperatures have been used to get axially local Nusselt numbers. These axially local Nusselt numbers have been averaged over the whole length of the duct to get the mean Nusselt number. Predictive friction factor and Nusselt number correlations developed by log-regression analysis have also been presented. Nusselt number correlation takes care of the thermal development length represented by the Graetz number, swirl and inertia force due to forced convection at large Reynolds number, buoyancy force due to natural convection at low Reynolds number represented by Rayleigh number and the geometrical parameters of wire-coil and helical screw-tape inserts. The thermohydraulic performance has been evaluated. The helical screw-tape inserts in combination with wire-coil inserts perform better than the individual enhancement technique acting alone for laminar flow through a circular tube up to a certain value of fin parameter.
In situ sediment dispersion estimates in the presence of discrete layers and gradients
Authors: Holland Charles W. , Dettmer Jan
Published: January 2013

One of the difficulties in validating sediment models has been the lack of reliable low frequency dispersion measurements. A reflection method is presented that yields in situ dispersion without sediment disturbance over a broad range of frequencies and can explicitly disentangle frequency-dependent effects of vertical structure, e.g., layers and gradients. Measurements on the outer shelf from 300 to 3000 Hz show that dispersion is a strong function of depth in the sediment column. The depth and frequency-dependent results generally agree well with independent measurements on core data. Cohesive sediments in the upper few meters exhibit a nearly frequency-independent sound speed and a nearly linear frequency dependence of attenuation. In the lower part of the sediment column the sediments are more granular: the lowest layer exhibits an attenuation with a peak frequency at 1100 Hz, where its dependence below and above trends to f2 and f1/2, respectively. While Biot theory predicts this dependence, its underlying physical explanation, fluid flow through interstitial pores, does not seem plausible for this sediment due to the unreasonable permeability value required. Viscous grain shearing theory also predicts this dependence, but it is not known whether the parameter values are reasonable.
Evolution of neuronal mechanisms for echolocation: Specializations for target-range computation in bats of the genus Pteronotus
Authors: Hechavarría Julio C. , Macías Silvio , Vater Marianne , Mora Emanuel C. , Kössl Manfred
Published: January 2013

Delay tuning was studied in the auditory cortex of Pteronotus quadridens. All the 136 delay-tuned units that were studied responded strongly to heteroharmonic pulse-echo pairs presented at specific delays. In the heteroharmonic pairs, the first sonar call harmonic marks the timing of pulse emission while one of the higher harmonics (second or third) indicates the timing of the echo. Delay-tuned units are organized chronotopically along a rostrocaudal axis according to their characteristic delay. There is no obvious indication of multiple cortical axes specialized in the processing of different harmonic combinations of pulse and echo. Results of this study serve for a straight comparison of cortical delay-tuning between P. quadridens and the well-studied mustached bat, Pteronotus parnellii. These two species stem from the most recent and most basal nodes in the Pteronotus lineage, respectively. P. quadridens and P. parnellii use comparable heteroharmonic target-range computation strategies even though they do not use biosonar calls of a similar design. P. quadridens uses short constant-frequency (CF)/frequency-modulated (FM) echolocation calls, while P. parnellii uses long CF/FM calls. The ability to perform “heteroharmonic” target-range computations might be an ancestral neuronal specialization of the genus Pteronotus that was subjected to positive Darwinian selection in the evolution.
Spectral timbre perception in ferrets: Discrimination of artificial vowels under different listening conditions
Authors: Bizley Jennifer K. , Walker Kerry M. M. , King Andrew J. , Schnupp Jan W. H.
Published: January 2013

Spectral timbre is an acoustic feature that enables human listeners to determine the identity of a spoken vowel. Despite its importance to sound perception, little is known about the neural representation of sound timbre and few psychophysical studies have investigated timbre discrimination in non-human species. In this study, ferrets were positively conditioned to discriminate artificial vowel sounds in a two-alternative-forced-choice paradigm. Animals quickly learned to discriminate the vowel sound /u/ from /ε/ and were immediately able to generalize across a range of voice pitches. They were further tested in a series of experiments designed to assess how well they could discriminate these vowel sounds under different listening conditions. First, a series of morphed vowels was created by systematically shifting the location of the first and second formant frequencies. Second, the ferrets were tested with single formant stimuli designed to assess which spectral cues they could be using to make their decisions. Finally, vowel discrimination thresholds were derived in the presence of noise maskers presented from either the same or a different spatial location. These data indicate that ferrets show robust vowel discrimination behavior across a range of listening conditions and that this ability shares many similarities with human listeners.
Direct measurement of the wavelength of sound waves in the human skull
Authors: McKnight Carmen L. , Doman Darrel A. , Brown Jeremy A. , Bance Manohar , Adamson Robert B. A.
Published: January 2013

The results of a study of the three-dimensional vibration of two dry human skulls in response to harmonic excitation are presented. The vibratory response exhibits three distinct types of motion across the range of audible frequencies. At low frequencies below 1000 Hz, whole-head quasi-rigid motion is seen. At the middle frequencies between 1000 and 6000 Hz, the motion exhibits a series of increasingly complex modal patterns. Above 6000 Hz, the response is wavelike and clear wavefronts can be distinguished in the vibration data. In this regime the relationship between wavelength and frequency is calculated and compared to a number of theories of skull vibration that have been proposed.
Prediction of flow induced sound and vibration of periodically stiffened plates
Authors: Maxit Laurent , Denis Vivien
Published: January 2013

Stiffened structures excited by the turbulent boundary layer (TBL) occur very frequently in engineering applications; for instance, in the wings of airplanes or the pressure hulls of submarines. To improve knowledge of the interaction between stiffened structures and TBL, this paper deals with the modeling of infinite periodically stiffened plates excited by TBL. The mathematical formulation of the problem is well-established in the literature. The originality of the present work relies on the use of a wavenumber-point reciprocity technique for evaluating the response of the plate to convected harmonic pressure waves. It follows a methodology for estimating the vibro-acoustic response of the plate excited by the TBL from the wall pressure spectrum and its displacements in the wavenumber space due to point excitations located at the receiving positions. The computing process can be reduced to the numerical integration of an analytical expression in the case of a periodically stiffened plate. An application to a naval test case highlights the effect of Bloch-Floquet waves on the vibrations of the plate and its radiated pressure in the fluid.
Effects of spatial and temporal integration of a single early reflection on speech intelligibility
Authors: Warzybok Anna , Rennies Jan , Brand Thomas , Doclo Simon , Kollmeier Birger
Published: January 2013

In order to study the interaction between the intelligibility advantage in rooms due to the presence of early reflections and due to binaural unmasking, a series of speech reception threshold experiments was performed employing a single reflection of the frontal target speech source as a function of its delay ranging from 0 to 200 ms. The direction of the reflection and the spatial characteristic of the interfering noise (diotic, diffuse, or laterally localized) were varied in the experiments. For the frontal reflection, full temporal integration was observed for all three noise types up to a delay of at least 25 ms followed by gradual intelligibility decay at longer delays. At 200 ms delay the reflection introduced additional intelligibility deterioration. For short delays, intelligibility was not reduced when the reflection was spatially separated from the direct sound in the diffuse and lateral noise conditions. A release from the deterioration effect at 200 ms delay was found for all spatially separated reflections. The suppression of a detrimental reflection was symmetrical in diffuse noise, but azimuth-dependent in lateral noise. This indicates an interaction of spatial and temporal processing of speech reflections which challenges existing binaural speech intelligibility models.
Depth dependence of wind-driven, broadband ambient noise in the Philippine Sea
Authors: Barclay David R. , Buckingham Michael J.
Published: January 2013

In 2009, as part of PhilSea09, the instrument platform known as Deep Sound was deployed in the Philippine Sea, descending under gravity to a depth of 6000 m, where it released a drop weight, allowing buoyancy to return it to the surface. On the descent and ascent, at a speed of 0.6 m/s, Deep Sound continuously recorded broadband ambient noise on two vertically aligned hydrophones separated by 0.5 m. For frequencies between 1 and 10 kHz, essentially all the noise was found to be downward traveling, exhibiting a depth-independent directional density function having the simple form cos θ, where θ ≤ 90° is the polar angle measured from the zenith. The spatial coherence and cross-spectral density of the noise show no change in character in the vicinity of the critical depth, consistent with a local, wind-driven surface-source distribution. The coherence function accurately matches that predicted by a simple model of deep-water, wind-generated noise, provided that the theoretical coherence is evaluated using the local sound speed. A straightforward inversion procedure is introduced for recovering the sound speed profile from the cross-correlation function of the noise, returning sound speeds with a root-mean-square error relative to an independently measured profile of 8.2 m/s.
Maximum-likelihood spatial spectrum estimation in dynamic environments with a short maneuverable array
Authors: Odom Jonathan L. , Krolik Jeffrey L. , Rogers Jeffrey S.
Published: January 2013

This work concerns the development of field directionality mapping algorithms for short acoustic arrays on mobile maneuverable platforms that avoid the left/right ambiguities and endfire resolution degradation common to longer non-maneuverable line arrays. In this paper, it is shown that short maneuverable arrays can achieve a high fraction of usable bearing space for target detection in interference-dominated scenarios, despite their lower array gain against diffuse background noise. Two narrowband techniques are presented which use the expectation-maximization maximum likelihood algorithm under different models of the time-varying field directionality. The first, derivative based maximum likelihood, uses a deterministic model while the second, recursive Bayes maximum likelihood, uses a stochastic model for the time-varying spatial spectrum. In addition, a broadband extension is introduced that incorporates temporal spectral knowledge to suppress ambiguities when the average sensor array spacing is greater than a half-wavelength. Dynamic multi-source simulations demonstrate the ability of a short, maneuvering array to reduce array ambiguities and spatial grating lobes in an interference dominated environment. Monte Carlo evaluation of receiver operating characteristics is used to evaluate the improvement in source detection achieved by the proposed methods versus conventional broadband beamforming.
Brainstem plasticity and modified loudness following short-term use of hearing aids
Authors: Munro Kevin J. , Merrett Jessica F.
Published: January 2013

Previous research has shown that the threshold of the middle ear acoustic reflex is modified in adult listeners following 1 week of continuous monaural sensory deprivation [Munro and Blount, J. Acoust. Soc. Am. 126, 568–571 (2009)]. The results of the present study provide evidence of plasticity in the brainstem of adult listeners following monaural auditory stimulation. Acoustic reflexes were obtained at a higher sound pressure level in the ear that had been fitted with a low-gain hearing aid for 5 days. These changes are in the opposite direction to those reported after sensory deprivation and are consistent with a gain control mechanism mediated by a process within the brainstem. Stimuli were reported as less loud after hearing aid use but the relationship with changes to the acoustic reflex threshold was not statistically significant.
Toddlers' recognition of noise-vocoded speech
Authors: Newman Rochelle , Chatterjee Monita
Published: January 2013

Despite their remarkable clinical success, cochlear-implant listeners today still receive spectrally degraded information. Much research has examined normally hearing adult listeners' ability to interpret spectrally degraded signals, primarily using noise-vocoded speech to simulate cochlear implant processing. Far less research has explored infants' and toddlers' ability to interpret spectrally degraded signals, despite the fact that children in this age range are frequently implanted. This study examines 27-month-old typically developing toddlers' recognition of noise-vocoded speech in a language-guided looking study. Children saw two images on each trial and heard a voice instructing them to look at one item (“Find the cat!”). Full-spectrum sentences or their noise-vocoded versions were presented with varying numbers of spectral channels. Toddlers showed equivalent proportions of looking to the target object with full-speech and 24- or 8-channel noise-vocoded speech; they failed to look appropriately with 2-channel noise-vocoded speech and showed variable performance with 4-channel noise-vocoded speech. Despite accurate looking performance for speech with at least eight channels, children were slower to respond appropriately as the number of channels decreased. These results indicate that 2-yr-olds have developed the ability to interpret vocoded speech, even without practice, but that doing so requires additional processing. These findings have important implications for pediatric cochlear implantation.
Band importance for sentences and words reexamined
Authors: Healy Eric W. , Yoho Sarah E. , Apoux Frédéric
Published: January 2013

Band-importance functions were created using the “compound” technique [Apoux and Healy, J. Acoust. Soc. Am. 132, 1078–1087 (2012)] that accounts for the multitude of synergistic and redundant interactions that take place among speech bands. Functions were created for standard recordings of the speech perception in noise (SPIN) sentences and the Central Institute for the Deaf (CID) W-22 words using 21 critical-band divisions and steep filtering to eliminate the influence of filter slopes. On a given trial, a band of interest was presented along with four other bands having spectral locations determined randomly on each trial. In corresponding trials, the band of interest was absent and only the four other bands were present. The importance of the band of interest was determined by the difference between paired band-present and band-absent trials. Because the locations of the other bands changed randomly from trial to trial, various interactions occurred between the band of interest and other speech bands which provided a general estimate of band importance. Obtained band-importance functions differed substantially from those currently available for identical speech recordings. In addition to differences in the overall shape of the functions, especially for the W-22 words, a complex microstructure was observed in which the importance of adjacent frequency bands often varied considerably. This microstructure may result in better predictive power of the current functions.
The influence of masker type on early reflection processing and speech intelligibility (L)
Authors: Arweiler Iris , Buchholz Jörg M. , Dau Torsten
Published: January 2013

Arweiler and Buchholz [J. Acoust. Soc. Am. 130, 996–1005 (2011)] showed that, while the energy of early reflections (ERs) in a room improves speech intelligibility, the benefit is smaller than that provided by the energy of the direct sound (DS). In terms of integration of ERs and DS, binaural listening did not provide a benefit from ERs apart from a binaural energy summation, such that monaural auditory processing could account for the data. However, a diffuse speech shaped noise (SSN) was used in the speech intelligibility experiments, which does not provide distinct binaural cues to the auditory system. In the present study, the monaural and binaural benefit from ERs for speech intelligibility was investigated using three directional maskers presented from 90° azimuth: a SSN, a multi-talker babble, and a reversed two-talker masker. For normal-hearing as well as hearing-impaired listeners, the directional and/or fluctuating (speech) maskers produced a similar benefit from ERs as obtained with the diffuse SSN, suggesting a monaural integration of the ERs and the DS for both types of maskers.
On the perception of speech in primary school classrooms: Ranking of noise interference and of age influence
Authors: Prodi Nicola , Visentin Chiara , Feletti Alice
Published: January 2013

It is well documented that the interference of noise in the classroom puts younger pupils at a disadvantage for speech perception tasks. Nevertheless, the dependence of this phenomenon on the type of noise, and the way it is realized for each class by a specific combination of intelligibility and effort have not been fully investigated. Following on a previous laboratory study on “listening efficiency,” which stems from a combination of accuracy and latency measures, this work tackles the problems above to better understand the basic mechanisms governing the speech perception performance of pupils in noisy classrooms. Listening tests were conducted in real classrooms for a relevant number of students, and tests in quiet were also developed. The statistical analysis is based on stochastic ordering and is able to clarify the behavior of the classes and the different impacts of noises on performance. It is found that the joint babble and activity noise has the worst effect on performance whereas tapping and external traffic noises are less disruptive.
Determining the bubble cap film thickness of bursting bubbles from their acoustic emissions
Authors: Deane Grant B.
Published: January 2013

A study of the sound generated by 2.5 mm radius bubbles bursting on the surface of fresh water is presented. The sound pulses are found to be sensitive to the time interval between the bubble reaching the water surface and bursting. Bubbles that burst within a few 10's of milliseconds behave like a Helmholtz resonator and radiate a swept chirp pulse. Bubbles that persist for 100's of milliseconds or more exhibit more complex acoustic behavior. An analysis of the resonator behavior provides an estimate of the film thickness in reasonable agreement with a fluid drainage model.
Near-field shock formation in noise propagation from a high-power jet aircraft
Authors: Gee Kent L. , Neilsen Tracianne B. , Downing J. Micah , James Michael M. , McKinley Richard L. , McKinley Robert C. , Wall Alan T.
Published: January 2013

Noise measurements near the F-35A Joint Strike Fighter at military power are analyzed via spatial maps of overall and band pressure levels and skewness. Relative constancy of the pressure waveform skewness reveals that waveform asymmetry, characteristic of supersonic jets, is a source phenomenon originating farther upstream than the maximum overall level. Conversely, growth of the skewness of the time derivative with distance indicates that acoustic shocks largely form through the course of near-field propagation and are not generated explicitly by a source mechanism. These results potentially counter previous arguments that jet “crackle” is a source phenomenon.
Anti-S antibodies: an unusual cause of haemolytic disease of the fetus and newborn (HDFN)
Authors: Pitan Christopher , Syed Azhar , Murphy W , Akinlabi Oluwafemi , Finan Alan
Published: January 2013

We report a case of haemolytic disease of the fetus and newborn due to anti-S antibodies. Baby G was born by emergency caesarean section at 35 weeks due to reduced fetal movement. Prior to delivery, antenatal screening revealed the mother's blood group was AB rhesus positive with anti-S antibody titres. The baby was pale but non-hydropic at birth with hepatosplenomegaly. Haemoglobin at birth was 5.23 g/dl and serum bilirubin 138 µmol/l. The baby required phototherapy, γ-globulin infusion and exchange transfusion with post-transfusion complications.
Immature fibrous dysplasia: a mixed radio-opaque radiolucent lesion
Authors: Nair Preeti P , Bhargava Darpan , Thomas Shaji , Shreenivas K
Published: January 2013

Fibrous dysplasia is a bone pathology characterised by abnormal differentiation of osteoblasts leading to replacement of normal marrow and cancellous bone by immature bone and fibrous stroma. A case report of a 20-year-old female patient with a chief complaint of a swelling in the right upper back tooth region, of 6 months duration which was diagnosed as an immature fibrous dysplasia is presented.
Is secondary preventive care improving? Observational study of 10-year trends in emergency admissions for conditions amenable to ambulatory care
Authors: Bardsley Martin , Blunt Ian , Davies Sian , Dixon Jennifer
Published: January 2013

Objective

To identify trends in emergency admissions for patients with clinical conditions classed as ‘ambulatory care sensitive’ (ACS) and assess if reductions might be due to improvements in preventive care.

Design

Observational study of routinely collected hospital admission data from March 2001 to April 2011. Admission rates were calculated at the population level using national population estimates for area of residence.

Participants

All emergency admissions to National Health Service (NHS) hospitals in England from April 2001 to March 2011 for people residents in England.

Main outcome measures

Age-standardised emergency admissions rates for each of 27 specific ACS conditions (ICD-10 codes recorded as primary or secondary diagnoses).

Results

Between April 2001 and March 2011 the number of admissions for ACS conditions increased by 40%. When ACS conditions were defined solely on primary diagnosis, the increase was less at 35% and similar to the increase in emergency admissions for non-ACS conditions. Age-standardised rates of emergency admission for ACS conditions had increased by 25%, and there were notable variations by age group and by individual condition. Overall, the greatest increases were for urinary tract infection, pyelonephritis, pneumonia, gastroenteritis and chronic obstructive pulmonary disease. There were significant reductions in emergency admission rates for angina, perforated ulcers and pelvic inflammatory diseases but the scale of these successes was relatively small.

Conclusions

Increases in rates of emergency admissions suggest that efforts to improve the preventive management of certain clinical conditions have failed to reduce the demand for emergency care. Tackling the demand for hospital care needs more radical approaches than those adopted hitherto if reductions in emergency admission rates for ACS conditions overall are to be seen as a positive outcome of for NHS.
REMARKS ON THE COSMOLOGICAL CONSTANT
Authors: FRAMPTON PAUL H.
Published: January 2013

The acceleration of the surface of last scatter (SLS) must somehow reflect the energy content within it. A test particle at the SLS is assumed to experience a linear combination of two forces: one Newtonian, the other pseudo-Newtonian describable by a cosmological constant Λ in general relativity. In the Λ description, which is surely too unimaginative, the size of Λ reflects only the comparable magnitudes of the Newtonian and pseudo-Newtonian forces; any claim of fine tuning due to quantum mechanics is probably illusory.
TRANSMITTING BIPARTITE AND MULTIPARTITE CORRELATIONS VIA SPIN CHAINS UNDER PHASE DECOHERENCE
Authors: AI JIAN-FENG , ZHANG JIAN-SONG , CHEN AI-XI
Published: January 2013

We investigate the transfer of bipartite (measured by cocurrence) and multipartite (measured by global discord) quantum correlations though spin chains under phase decoherence. The influence of phase decoherence and anisotropy parameter upon quantum correlations transfer is investigated. On the one hand, in the case of no phase decoherence, there is no steady state quantum correlations between spins. On the other hand, if the phase decoherence is larger than zero, the bipartite quantum correlations can be transferred through a Heisenberg XXX chain for a long time and there is steady state bipartite entanglement. For a Heisenberg XX chain, bipartite entanglement between two spins is destroyed completely after a long time. Multipartite quantum correlations of all spins are more robust than bipartite quantum correlations. Thus, one can store multipartite quantum correlations in spin chains for a long time under phase decoherence.
SOME OBSERVATIONS ON THE BEHAVIOR OF THE METHOD OF FUNDAMENTAL SOLUTIONS IN 3D ACOUSTIC PROBLEMS
Authors: GODINHO L. M. C. , COSTA E. G. A. , PEREIRA A. S. C. , SANTIAGO J. A. F.
Published: January 2013

The benchmark problem of room acoustics, consisting on the determination of the three-dimensional (3D) sound field generated by a point source placed within a closed acoustic space is here addressed by means of the Method of Fundamental Solutions (MFS). The focus of this paper is on the behavior of a MFS numerical frequency domain approach with regards to stability, accuracy, and efficiency. Strategies of improving stability and accuracy of the method such as the use of different distributions of collocation points and virtual sources or an singular value decomposition (SVD) solver are also analyzed. It has been found that these strategies allowed increasing accuracy and attaining stability. Comparison with a classical BEM model was also performed, and has shown that the MFS can reach excellent accuracy making use of smaller-sized equation systems.
A STABLE LARGE DEFORMATION CORRECTED SPH METHOD BASED ON STABILIZED CONFORMING NODAL INTEGRATION AND LAGRANGIAN KERNELS
Authors: WANG S.
Published: January 2013

In this paper, we propose a Galerkin-based smoothed particle hydrodynamics (SPH) formulation with moving least-squares meshless approximation, applied to solid mechanics and large deformation. Our method is truly meshless and based on Lagrangian kernel formulation and stabilized nodal integration. The performance of the methodology proposed is tested through various simulations, demonstrating the attractive ability of particle methods to handle severe distortions and complex phenomena.
Palaeoenvironments of the Late Miocene Prüedo Basin: implications for the uplift of the Central Pyrenees
Authors: Ortuño María , Martí Anna , Martín-Closas Carles , Jiménez-Moreno Gonzalo , Martinetto Edoardo , Santanach Pere
Published: January 2013

The nature, structure and extent of a palaeo-basin sedimentary infill exposed in the Aran valley (Central Pyrenees) was studied by combining stratigraphical and biostratigraphical analyses and an audio-magnetotelluric survey. The basin developed on top of a pre-existing peneplain and was formed by the North Maladeta Fault activity. The fluvio-palustrine sequence filling the basin was at least 100 m thick. Specimens of the taxon
Hippuris
cf.
parvicarpa
Nikitin were identified for the first time in a European palaeoflora. The palynological and carpological analyses allowed us to (1) constrain the age of the basin infill as Vallesian (11.1–8.7 Ma), (2) characterize the vegetation of the belt surrounding the basin as a mainly temperate to warm-temperate assemblage, and (3) estimate the palaeoaltitude of the site at between 700 and 1000 m, which leads to an altitude change of 900–1200 m for the North Maladeta Fault downthrown block and 1640–1640 m for the upthrown block. These data allowed us to estimate the regional uplift of the area at between 0.08 and 0.19 mm a
−1
. The different exhumation values obtained by other researchers for sites located at both sides of the North Maladeta Fault are in agreement with its activity as a normal fault since the Late Miocene.

Supplementary materials

Details of the data acquisition, processing and modelling for the Porèra profile are available at
www.geolsoc.org.uk/SUP18551
.
Duration of the Early Bajocian and the associated δ
13
C positive excursion based on cyclostratigraphy
Authors: Sucheras-Marx Baptiste , Giraud Fabienne , Fernandez Vincent , Pittet Bernard , Lecuyer Christophe , Olivero Davide , Mattioli Emanuela
Published: January 2013

The Early Bajocian, about 172 Ma ago, was a period of tectonic changes, a global carbon-isotope positive excursion, and biological diversification of marine invertebrates (e.g. ammonites, radiolarians and coccolithophores). Unfortunately, both the duration of the Early Bajocian and the associated palaeoenvironmental changes are still poorly constrained. We propose here an estimate of the duration of this sub-stage based on a cyclostratigraphic analysis of the carbonate content from the Chaudon–Norante section, French Subalpine Basin, France. The Chaudon–Norante succession has been correlated with Les Dourbes section using greyscale variations to detect possible local hiatuses. The duration estimated here for the entire Early Bajocian is 4.082 Ma. Two intervals were identified in the positive δ
13
C excursion: an increase of carbon isotope values lasting 1.36 Ma and climax isotope values lasting for 2.72 Ma. A cooling at high latitudes and warming at low latitudes may have enhanced the Earth’s temperature gradient leading to an increase in humidity, which in turn triggered ocean eutrophication at the origin of the δ
13
C positive excursion.

Supplementary material:

The complete dataset presented in the paper, a colour version of the figure 8 and correlation of δ
13
C excursions between our studied site and contemporaneous sites are available at
www.geolsoc.org.uk/SUP18555
.
Backarc basin inversion and subcontinental mantle emplacement in the crust: kilometre-scale folding and shearing at the base of the proto-Alborán lithospheric mantle (Betic Cordillera, southern Spain)
Authors: Hidas Károly , Booth-Rea Guillermo , Garrido Carlos J. , Martínez-Martínez José Miguel , Padrón-Navarta José Alberto , Konc Zoltán , Giaconia Flavio , Frets Erwin , Marchesi Claudio
Published: January 2013

To constrain the latest evolutionary stages and mechanisms of exhumation and emplacement of subcontinental peridotites in the westernmost Mediterranean, we present here a detailed structural study of the transition from granular spinel peridotite to plagioclase tectonite in the western Ronda Peridotite (Betic Cordillera, southern Spain). We show that the plagioclase tectonite foliation represents an axial surface particularly well developed in the reverse limb of a downward facing moderately plunging and moderately inclined synform at the base of the Ronda massif. The fold limbs are cut by several mylonitic and ultramylonitic shear zones with top-to-the-SW sense of shear. After restoring the middle to late Miocene vertical-axis palaeomagnetic rotation and the early Miocene tectonic tilting of the massif, these studied structures record southward-directed kinematics. We propose a geodynamic model in which folding and shearing of an attenuated mantle lithosphere occurred by backarc basin inversion during late Oligocene (23–25 Ma) southward collision of the Alborán Domain with the palaeo-Maghrebian passive margin, leading to the intracrustal emplacement of peridotites in the earliest Miocene (21–23 Ma).
The role of strain localization in magma injection into a transtensional shear zone (Variscan belt, SW Iberia)
Authors: Pereira M. Francisco , Chichorro Martim , Fernández Carlos , Silva J. Brandão , Matias Filipa V.
Published: January 2013

This study deals with the interaction between deformation and magmatism in mid- to deep-crustal domains. The relation is analysed between migmatites and shear zones and the spatial distribution of leucogranitoid veins and dykes running through a footwall migmatite system, and reaching a transtensional shear zone operated under amphibolite- to greenschist-facies metamorphic conditions (Boa Fé shear zone, Variscan belt, SW Iberia). Statistical results show that the frequency of width and spacing of the leucogranitoid dykes conform to power-law distributions comparable with observations in volcanic systems. The fractal geometry of the distribution of leucogranitoid dykes highlights the development of a dense framework of thinner weakly or non-mineralized veins and dykes formed at higher nucleation/growth ratios in the footwall migmatite system that contrasts with the emplacement of thicker dykes associated with strongly mineralized thinner veins within the shear zone. The volume of injected leucogranitoid dykes in the shear zone is lower as compared with the footwall and is comparable with an expanding footwall shear zone with non-coaxial flow and volume increase. The Boa Fé shear zone seems to form a physical barrier to the transport of magma to the hanging wall.
Oligocene–Miocene burial and exhumation of the Southern Pyrenean foreland quantified by low-temperature thermochronology
Authors: Fillon Charlotte , Gautheron Cécile , van der Beek Peter
Published: January 2013

The central Pyrenees experienced an episode of rapid exhumation in Late Eocene–Early Oligocene times. Erosional products shed from the range during this time were deposited in large palaeovalleys of the southern flank of the Axial Zone, leading to significant sediment accumulation. A recent numerical modelling study of the post-orogenic exhumation and relief history of the central Axial Zone allowed us to constrain this valley-filling episode in terms of timing and thickness of conglomeratic deposits. This paper aims to test these results for the southern fold-and-thrust belt using apatite fission-track and (U–Th)/He analysis on detrital samples from the Tremp–Graus and Ager basins. Inverse thermal-history modelling of the low-temperature thermochronology data indicates that the fold-and-thrust belt was covered during the Late Eocene to Miocene by 0.7–1.6 km of sediments and confirms the timing of re-excavation of the valleys during the Miocene. A detailed analysis of the apatite (U–Th)/He results shows that the significant scatter in grain ages can be explained by the influence of alpha-recoil damage with varying effective uranium content together with distinct pre-depositional thermal histories; the age scatter is consistent with initial exhumation of the sediment sources during the Triassic and Early Cretaceous.

Supplementary materials:

Modelling results obtained using the

Gautheron
et al
. (2009)

diffusion algorithm are available at
www.geolsoc.org.uk/SUP18560
.
Ediacaran Gaskiers Glaciation of Newfoundland reconsidered
Authors: Retallack G. J.
Published: January 2013

Newly discovered palaeosols in the Gaskiers Formation of Newfoundland provide a new perspective on its palaeoenvironment, and are evidence that it was not a deep submarine tillite, nor an anoxic deep-sea floor, nor a ‘cap carbonate’ from extreme geochemical perturbation of the global ocean. Discovery of oxidized palaeosols and re-evaluation of sedimentary facies and stratigraphic relationships now suggest reinterpretation as a coastal plain with glacial moraines in the forearc basin of a continental volcanic arc, like modern Japan. Ediacaran palaeosols of the Gaskiers Formation lack large root traces, but show soil profile differentiation (clay enrichment and depletion of alkali and alkaline earth elements at the expense of feldspar and rock fragments) and diagnostic soil structures (blocky peds, argillans, sepic plasmic fabric). These palaeosols are evidence of a humid temperate climate and marked marine regression accompanying the Gaskiers Glaciation of the early Ediacaran (580 Ma). Geochemical weathering trends in the palaeosols, especially phosphorus depletion, are characteristic of biologically active soils. Ediacaran microbial earth ecoystems may have been responsible for filamentous disruption of bedding in the palaeosols.
Metabolic derangements in COPD muscle dysfunction
Authors: Puente-Maestu Luis , Lázaro Alberto , Humanes Blanca
Published: January 2013

Mitochondrial muscle alterations are common in patients with chronic obstructive pulmonary disease (COPD) and manifest mainly as decreased oxidative capacity and excessive production of reactive oxygen species (ROS). The significant loss of oxidative capacity observed in the quadriceps of COPD patients is mainly due to reduced mitochondrial content in the fibers, a finding consistent with the characteristic loss of type I fibers observed in that muscle. Decreased oxidative capacity does not directly limit maximum performance; however, it is associated with increased lactate production at lower exercise intensity and reduced endurance. Since type I fiber atrophy does not occur in respiratory muscles, the loss of such fibers in the quadriceps could be to the result of disuse. In contrast, excessive production of ROS and oxidative stress are observed in both the respiratory muscles and the quadriceps of COPD patients. The causes of increased ROS production are not clear, and a number of different mechanisms can play a role. Several mitochondrial alterations in the quadriceps of COPD patients are similar to those observed in diabetic patients, thus suggesting a role for muscle alterations in this comorbidity. Amino acid metabolism is also altered. Expression of peroxisome proliferator-activated receptor-γ coactivator-1α mRNA is low in the quadriceps of COPD patients, which could also be a consequence of type I fiber loss; nevertheless, its response to exercise is not altered. Patterns of muscle cytochrome oxidase gene activation after training differ between COPD patients and healthy subjects, and the profile is consistent with hypoxic stress, even in nonhypoxic patients.
Inflammatory Bowel Disease: Dysfunction of Autophagy?
Authors: Scharl Michael , Rogler Gerhard
Published: January 2013

Recent genome-wide association studies identified single nucleotide polymorphisms within gene loci, encoding autophagy genes, e.g. the autophagy-related 16-like 1 (ATG16L1) and the immunity-related GTPase family M (IRGM), as an important risk factor for the onset of chronic inflammatory diseases such as Crohn’s disease (CD) or rheumatoid arthritis. CD is characterized by a breakdown of the intestinal epithelial barrier function leading to an overwhelming and uncontrolled immune response to bacterial antigens. Autophagy, and therefore ATG16L1 and IRGM, are critically involved in the innate immune response to invading pathogens. Dysfunction of these molecules results in the increased survival of intracellular bacteria, defective antigen presentation and proinflammatory cytokine secretion. Interestingly, autophagy can also be regulated by other CD susceptibility genes, such as nucleotide oligomerization domain 2 or protein tyrosine phosphatase nonreceptor type 2, and the presence of the CD-associated variations within these genes results in comparable effects. ATG16L1 also plays a crucial role in maintaining Paneth cell function and morphology, while IRGM seems to be associated with mitochondrial function and apoptosis. Dysfunction of these molecules, i.e. of autophagy in vivo, is clearly associated with the increased bacterial infection and the onset of colitis. Interestingly, the phenotype of aberrant Paneth cells and dextran sodium sulphate-induced colitis in ATG16L1 hypomorphic mice closely resembles human CD. Taken together, the available data strongly suggest an important role for autophagy in maintaining intestinal homeostasis, and dysfunction of autophagy seems to be a major risk factor for the onset of chronic intestinal inflammation.