Frequency Of Exchanges Research Articles

GPU accelerated cell-based adaptive mesh refinement on unstructured quadrilateral grid

A GPU accelerated inviscid flow solver is developed on an unstructured quadrilateral grid in the present work. For the first time, the cell-based adaptive mesh refinement (AMR) is fully implemented on GPU for the unstructured quadrilateral grid, which greatly reduces the frequency of data exchange between GPU and CPU. Specifically, the AMR is processed with atomic operations to parallelize list operations, and null memory recycling is realized to improve the efficiency of memory utilization. It is found that results obtained by GPUs agree very well with the exact or experimental results in literature. An acceleration ratio of 4 is obtained between the parallel code running on the old GPU GT9800 and the serial code running on E3-1230 V2. With the optimization of configuring a larger L1 cache and adopting Shared Memory based atomic operations on the newer GPU C2050, an acceleration ratio of 20 is achieved. The parallelized cell-based AMR processes have achieved 2x speedup on GT9800 and 18x on Tesla C2050, which demonstrates that parallel running of the cell-based AMR method on GPU is feasible and efficient. Our results also indicate that the new development of GPU architecture benefits the fluid dynamics computing significantly.

Novel glyceryl glucoside is a low toxic alternative for cryopreservation agent

Glyceryl glucoside (GG, α-d-glucosyglycerol) is a natural glycerol derivative found in alcoholic drinks. Recently GG has been used as an alternative for glycerol in cosmetic products. However, the safety of using GG is still unclear. Currently, dimethyl sulfoxide (DMSO) and glycerol are wildly used in cryopreservation. Despite GG being a derivative of glycerol, the ability of GG in cryopreservation is still unknown. By using a system of Chinese Hamster Ovary cells (CHO), A549 cells and AG1522 cells, the study examined the cryoprotective effects of DMSO, glycerol and GG. Cytotoxic and genotoxic responses induced by the three chemicals were also investigated with CHO to determine the safety of GG for cosmetic products. Our data suggests that GG has great cryopresearvation ability in the concentration of 30%–40% (v/v).For cytotoxic studies, DMSO showed the highest cytotoxicity above 3% (v/v) in cell doubling time delay among three chemicals. For the acute cytotoxicity with trypan blue dye exclusion assay, GG showed stronger cell killing effect within 24 h above 4% (v/v). For the continuous cytotoxicity with colony formation assay for 7 days, DMSO showed significantly reduced clonogenic ability above 2%.In genotoxicity studies, CHO treated with glycerol at 2% concentration induced three times higher frequencies of sister chromatid exchange (SCE) than background levels. GG did not induce significant amounts of SCE compared to background. Micronuclei formation was equally observed in the 2% and above concentrations of glycerol and GG.Our data showed that GG has significant effects on cryopreservation compared to DMSO. Glycerol and GG have similar cytotoxicity effects to CHO, but glycerol induced genotoxic responses in the same concentration. Therefore, we conclude that GG may be a safer alternative compound to glycerol in cosmetic products and safer alternative to DMSO in cryopreservation.

Neoteric HANFISC–SSSC based on MOPSO technique aimed at oscillation suppression of interconnected multi‐source power systems

Alleviating dynamic oscillations of the tie-line power exchange and area frequencies in affected interconnected power systems caused by loading condition changes is the prominent responsibility of automatic generation control (AGC). To compensate such the load-changes and also suppress these oscillations, the application of the flexible AC transmission systems (FACTS) can be assigned as one of the practical and effective approaches. In this study, the static synchronous series compensator (SSSC) which is one the series FACTS families is engaged to enhance the overall dynamic performance of multi-area multi-source interconnected power system. Likewise, accomplished endeavours in this regard are led to exude the hierarchical adaptive neuro fuzzy inference system controller–SSSC (HANFISC–SSSC) to suppress both prominent issues in multi-area interconnected power systems i.e.: the low frequency oscillations and the tie-line power exchange deviations. Hereof also, implementation of multi-objective optimisation technique is not avoidable. Due to high efficiency of multi objective particle swarm optimisation (MOPSO) to unravel the non-linear objectives, it has been used to solve the optimisation problem. To verify the high performance of suggested HANFISC–SSSC, two different multi-area interconnected power systems i.e.: two-area hydro–thermal–diesel and three-area hydro–thermal power systems have been considered for this study. In the interim, the capability of HANFISC–SSSC has been perfectly and precisely evaluated and compared with conventional SSSC by incidence of the step load perturbation in all areas of both the test power systems. To sum up, the simulations results obtained from both the power systems have transparently corroborated high performance of HANFISC–SSSC compared with conventional SSSC.

Students’ verbal exchanges and dynamics during Sport Education

In physical education (PE), children frequently participate in teams and the exchanges that transpire shape their perspectives and subsequently, influence learning. While Sport Education is one pedagogical model designed to enhance social exchanges through team membership, we previously identified the need for additional research to monitor these exchanges more closely. This study examined the verbal exchanges of students in two fourth grade PE classes participating in a season of team handball. One mixed-skill team from Class 1 (a heterogeneous skill league) and one low-skill team from Class 2 (a homogeneous skill league) were selected for in-depth study. Data collection included videotaped lessons from each team. Data analysis produced descriptive results of the frequency and focus of students’ individual exchanges. Our results indicated middle-to-high status students had higher rates of exchanges at the commencement of the season segments. Students in the homogeneous league had higher frequencies of exchanges than those in the heterogeneous league, and the focus of exchanges predominantly included on-task exchanges for the skill, in both skill leagues. This study highlights the potential for varied rates of exchange, based on student characteristics and unit design. Careful consideration for these factors should be employed to determine optimal learning environments for students.

Proton NMR study of spin dynamics in the magnetic organic chainsM(hfac)3NITEt(M=Eu3+,Gd3+)

In this work, we present a nuclear magnetic resonance (NMR) study of the spin dynamics in the rare-earth-based low-dimensional molecular magnetic chains $\mathrm{Eu}{(\mathrm{hfac})}_{3}\mathrm{NITEt}$ and $\mathrm{Gd}{(\mathrm{hfac})}_{3}\mathrm{NITEt}$ (in short, Eu-Et and Gd-Et). Although both samples are based on the same chemical building block, [(${\mathrm{hfac})}_{3}\mathrm{NITEt}]$, their magnetic properties change dramatically when the ${\mathrm{Eu}}^{3+}$ ion, which is nonmagnetic at low temperatures, is substituted by the magnetic ${\mathrm{Gd}}^{3+}$ ion. The present proton NMR investigation shows that, down to the lowest investigated temperature ($T=1.5$ K for Gd-Et and $T=3$ K for Eu-Et), the Eu-Et chain behaves as a one-dimensional Heisenberg model with antiferromagnetic exchange coupling ($J=\ensuremath{-}20$ K) between $s=1/2$ organic radicals, and has a $T$-independent exchange frequency (${\ensuremath{\omega}}_{e}=2.6\ifmmode\times\else\texttimes\fi{}{10}^{12}$ rad/s). In the Gd-Et chain, in contrast, a competition arises between nearest-neighbor ferromagnetic coupling and next-nearest-neighbor antiferromagnetic coupling; moreover, two phase transitions have previously been found, in agreement with Villain's conjecture: a first transition, at ${T}_{0}=2.2$ K, from a high temperature paramagnetic phase to a chiral spin liquid phase, and a second transition, at ${T}_{N}=1.9$ K, to a three-dimensional helical spin solid phase. Contrary to the Eu-Et chain (whose three-dimensional ordering temperature is estimated to insurge at very low, ${T}_{N}\ensuremath{\approx}0.3$ K), critical spin dynamics effects have been measured in the Gd-Et chain on approaching ${T}_{N}=1.9$ K: namely, a divergence of the proton nuclear spin-lattice relaxation rate $1/{T}_{1}$, which in turn produces a sudden wipe-out of the NMR signal in a very narrow ($\mathrm{\ensuremath{\Delta}}T\ensuremath{\sim}0.04$ K) temperature range above ${T}_{N}$. Below ${T}_{N}$, an inhomogeneous broadening of the NMR line indicates a complete spin freezing. At ${T}_{0}=2.2$ K, instead, such critical effects are not observed because NMR measurements probe the two-spin correlation function, while the chiral spin liquid phase transition is associated with a divergence of the four-spin correlation function.

Three-Color Chromosome Painting as Seen through the Eyes of mFISH: Another Look at Radiation-Induced Exchanges and Their Conversion to Whole-Genome Equivalency.

Whole-chromosome painting (WCP) typically involves the fluorescent staining of a small number of chromosomes. Consequently, it is capable of detecting only a fraction of exchanges that occur among the full complement of chromosomes in a genome. Mathematical corrections are commonly applied to WCP data in order to extrapolate the frequency of exchanges occurring in the entire genome [whole-genome equivalency (WGE)]. However, the reliability of WCP to WGE extrapolations depends on underlying assumptions whose conditions are seldom met in actual experimental situations, in particular the presumed absence of complex exchanges. Using multi-fluor fluorescence in situ hybridization (mFISH), we analyzed the induction of simple exchanges produced by graded doses of 137Cs gamma rays (0–4 Gy), and also 1.1 GeV 56Fe ions (0–1.5 Gy). In order to represent cytogenetic damage as it would have appeared to the observer following standard three-color WCP, all mFISH information pertaining to exchanges that did not specifically involve chromosomes 1, 2, or 4 was ignored. This allowed us to reconstruct dose–responses for three-color apparently simple (AS) exchanges. Using extrapolation methods similar to those derived elsewhere, these were expressed in terms of WGE for comparison to mFISH data. Based on AS events, the extrapolated frequencies systematically overestimated those actually observed by mFISH. For gamma rays, these errors were practically independent of dose. When constrained to a relatively narrow range of doses, the WGE corrections applied to both 56Fe and gamma rays predicted genome-equivalent damage with a level of accuracy likely sufficient for most applications. However, the apparent accuracy associated with WCP to WGE corrections is both fortuitous and misleading. This is because (in normal practice) such corrections can only be applied to AS exchanges, which are known to include complex aberrations in the form of pseudosimple exchanges. When WCP to WGE corrections are applied to true simple exchanges, the results are less than satisfactory, leading to extrapolated values that underestimate the true WGE response by unacceptably large margins. Likely explanations for these results are discussed, as well as their implications for radiation protection. Thus, in seeming contradiction to notion that complex aberrations be avoided altogether in WGE corrections – and in violation of assumptions upon which these corrections are based – their inadvertent inclusion in three-color WCP data is actually required in order for them to yield even marginally acceptable results.

Projection Pursuit-Based Microcystis Bloom Warning in a Riverside Lake

A high-dimensional driving function for Microcystis bloom warning was developed, in which both the inhibition and promotion impacts on Microcystis growth activation energy are integrally considered. Five factors, including flow disturbance, temperature, light intensity, nutrient concentration, and biological inhibition, are embedded in the equation, which results in a high-dimensional problem. The projection pursuit principle was applied for dimension reduction to resolve the numerical problem, and an integrated hydro-environmental model was established. Jinshan Lake, a typical riverside lake, was selected as the research area, and six bloom grades were determined for warning analysis. Based on the established model, the processes of Microcystis growth under varied hydrodynamic conditions were simulated. It was found that the established warning model could well reveal the Microcystis bloom processes in Jinshan Lake. The low-water year was characterized by the largest number of days on which Microcystis bloom might occur for its poor water exchange frequency; The areas where Microcystis bloom might occur in the flood seasons of high-water year, common-water year, and low-water year varied with the uneven-distributed dynamic conditions, which were respectively 0.15, 0.91, and 1.26 km2.

Is journalism a transnational field? Asymmetrical relations and symbolic domination in online news

Are all transnational exchanges ‘fielded’? This article explores the limits of the concept of transnational field by focusing on the case of journalism. At first glance, journalism might seem to be the perfect example of a transnational field. The frequency, speed and extent of international exchanges between media outlets has increased dramatically with the development of online news, leading media scholars to develop the concept of ‘global news’. Yet I argue that such international exchanges do not necessarily constitute a field. Using ethnographic methods, I analyse the circulation of online news between the United States and France, two countries with strikingly different journalistic traditions. Specifically, I compare two editorial partnerships between US and French websites, one linking prestigious online magazines across the Atlantic and the other connecting tabloid-oriented news sites. I find that editorial content does not circulate seamlessly between the two countries. Based on this study, the article proposes three criteria that must be met for transnational fields to exist: competition over the legitimate definition of the field, reciprocal field effects, and the existence of common stakes. More broadly, the article contributes to defining the limits of the concept of ‘transnational field’ for the study of international exchanges.

Quantifying dispersal from hydrothermal vent fields in the western Pacific Ocean

Hydrothermal vent fields in the western Pacific Ocean are mostly distributed along spreading centers in submarine basins behind convergent plate boundaries. Larval dispersal resulting from deep-ocean circulations is one of the major factors influencing gene flow, diversity, and distributions of vent animals. By combining a biophysical model and deep-profiling float experiments, we quantify potential larval dispersal of vent species via ocean circulation in the western Pacific Ocean. We demonstrate that vent fields within back-arc basins could be well connected without particular directionality, whereas basin-to-basin dispersal is expected to occur infrequently, once in tens to hundreds of thousands of years, with clear dispersal barriers and directionality associated with ocean currents. The southwest Pacific vent complex, spanning more than 4,000 km, may be connected by the South Equatorial Current for species with a longer-than-average larval development time. Depending on larval dispersal depth, a strong western boundary current, the Kuroshio Current, could bridge vent fields from the Okinawa Trough to the Izu-Bonin Arc, which are 1,200 km apart. Outcomes of this study should help marine ecologists estimate gene flow among vent populations and design optimal marine conservation plans to protect one of the most unusual ecosystems on Earth.

Dynamic adverse selection and the supply size

In this paper we examine the problem of dynamic adverse selection in a stylized market where the quality of goods is a seller׳s private information while the realized distribution of qualities is public information. We obtain that full trade occurs in every dynamic competitive equilibrium. Moreover, we show that if prices can be conditioned on the supply size then a dynamic competitive equilibrium always exists, while it fails to exist if prices cannot be conditioned on the supply size and the frequency of exchanges is high enough. We conclude that the possibility to condition prices on the supply size allows us to reach efficiency in the limit for exchanges becoming more and more frequent, while otherwise the welfare loss due to delays of exchanges remains bounded away from zero.

Investigation of unstable solids circulation behavior in a circulating fluidized bed with sweeping bend return using pressure frequency analysis

The unstable solids circulation behavior in a circulating fluidized bed (CFB) with sweeping bend return is investigated by monitoring pressure fluctuations in a bench-scale model. The pressure fluctuations at the top and bottom of the riser and downer are processed using the Fast Fourier Transform (FFT) technique to extract the dominant frequency and its amplitude in order to quantify the effects of riser inlet gas velocity, valve opening and bed inventory on the operation of the unit. The differential pressure drop fluctuations between riser and downer are processed in a similar manner. The study reveals that the unstable solids circulation behavior is cyclical vis-a-vis gas–solids flow pattern and solids exchange between riser and downer, named as solids oscillation circulation behavior. A dominant frequency of 0.25Hz is observed for all pressure fluctuation signals corresponding to the cyclical change of bed inventory and gas flow rate in riser and downer induced by the oscillation circulation behavior. An additional dominant frequency for the pressure fluctuation signals at the riser and downer bottom is also observed related to the gas–solid flow pattern. The solids exchange frequency is strongly related to the dominant frequency of the differential pressure drop. The work also demonstrates that the oscillation behavior is activated by a critical inlet gas velocity or valve opening and that the oscillation frequency increases with the decrease of inlet gas velocity, while it does not change with the valve opening. The solids exchange amount decreases with the decrease of gas flow and small percentage valve opening. The oscillation behavior changes from sine model to rectangular with the increase of bed inventory and thus slugging solids circulation is established.

How do teachers evaluate their parent communication competence? Latent profiles and relationships to workplace behaviors

Parent-teacher communication competence, frequency of exchange on parent-related issues with colleagues and time spent working with parents were measured with questionnaires in a sample of 677 German mathematics teachers. A latent class analysis revealed four groups of teachers: 24% showed high, 36% showed medium and 16% showed lower levels of communication competence with balanced profiles. A fourth profile (24%) showed a strong focus on pragmatic problem solving in communication with parents. The profiles differed in the extent of their exchange with colleagues on parent-related issues. No relationships were found regarding the time spent talking to parents.

Cytogenetic findings in patients diagnosed with breast cancer having undergone adjuvant chemotherapy regimens.

The aim of the present study was to investigate DNA damage in peripheral blood lymphocytes of breast cancer (BC) patients before and after administration of chemotherapy. We analyzed the frequency of sister chromatid exchange (SCE), occurrence of micronuclei (MN), and lymphocyte proliferation rate index (PRI) as cytogenetic markers in 28 female BC patients before and after chemotherapy, and in 20 age-matched healthy female volunteers. Prior to treatment, BC patients showed significantly increased background levels of SCE and MN, and lowered PRIs compared to healthy women. In comparison with pre-treatment levels, SCE and MN frequencies were significantly elevated and PRI reduced in blood samples collected after chemotherapy. Our findings indicate that SCE, MN, and PRI may serve as sensitive biomarkers for routine detection of the genetic abnormalities that may occur following administration of antineoplastic drugs in the clinical setting, as well as for the monitoring of high-risk patients receiving chemotherapy for BC.

Personality, negative social exchanges, and physical health among bereaved adults.

While much research has investigated the association between personality and health, little research has done so using a bereaved sample. Additionally, little research has investigated how personality influences the frequency of negative social exchanges bereaved individuals receive. This study utilized a structural equation model to investigate the associations among age, gender, personality, negative social exchanges, length of bereavement, and self-reported physical health in a sample of bereaved adults. Results indicated that personality was associated with negative social exchanges and physical health. Therefore, these variables are important and should be studied further in this context.

Release of Nitrogen and Phosphorus from Aquaculture Farms to Selangor River, Malaysia

The release of nitrogen and phosphorus from aquaculture ponds to Selangor River, Malaysia was estimated. The concentrations of nitrogen and phosphorus in aquaculture ponds were always higher than those in the river, their primary water source, indicating that the aquaculture ponds are sources of nitrogen and phosphorus in Selangor River. From the careful interview with aquaculture managers, the frequency of water exchange, the number of harvesting, and the amount of feeds added, the total volume of water released to the Selangor River was also obtained. The total amount of nitrogen and phosphorus added to each aquaculture pond was estimated to be about 700 kg N and 60 kg P per year, respectively. About 100-200 kg N and 10-15 kg P were estimated to be released with the waste water per pond per year, accounting for 20-30% of nitrogen and phosphorus in added feeds. It is important for us to precisely estimate the fates of nutrients for the better management and sustainable development of aquaculture industries. Our data may help to improve aquaculture management in future.

Influence of Radiotherapy on Frequency of Sister Chromatid Exchange, Micronuclei and Binuclear Cells in Breast Cancer Patients

The aim of this study was to evaluate any cytogenetic change in sister chromatid exchange (SCE), micronuclei (MN) and binuclear cell (BNC) of peripheral blood lymphocytes in breast cancer patients treated with postoperative radiation therapy (RT). Frequency of the SCE, MN and BNC were examined in 22 breast cancer patients received RT and 10 healthy individuals. All parameters were measured before (RT-a), at the completion of (RT-b) and three months after the completion of (RT-c) RT. A significant difference emerged in SCE (p=0.008) and MN (p=0.004) between RT-a and control groups. There was not any statistically significant difference in the SCE frequencies between RT-b and RT-c measurements. The frequencies of MN were also significantly higher in RT-b (p=0.005) and RT-c (p=0.005) than in control group. MN levels decreased to pre-RT levels three months after completion of treatment. Increasing MN and SCE frequencies following radiotherapy is an expected situation. Decrease in MN frequency at 3-month after the completion of RT suggests that expected repair continues. Persistent SCE at the same period suggests that recovery in SCE has not completed yet and a longer period of time is needed.

Evaluation of the frequency of sister chromatid exchanges and micronuclei in children with type-1 diabetes mellitus

Evaluation of the frequency of sister chromatid exchanges and micronuclei in children with type-1 diabetes mellitus

Evaluation of Sister Chromatid Exchanges and Hypoxanthine guanine phosphoribosyl transferase Gene Mutation Assay in Peripheral Lymphocytes of Workers Exposed to Radiation at Al-Tuwaitha Site

The present study aims at using the biological techniques in a genotoxicity assessment of low doses of radiation in samples of workers in Al-Tuwaitha site due to decommissioning to radioactive contamination as a result of work. This study included 50 male blood samples, aged 35 - 63 years as well as 35 blood samples from non-smokers and non-alcoholic as control group which included 25 male and 10 female aged 25 -57 years. The endpoints used were sister chromatid exchange (SCE) and hypoxanthine guanine phosphoribosyl transferase (HPRT) mutation assay. The sister chromatid exchange in the human lymphocyte for radiation worker was significantly (P<0.05) higher than in the control group. While the results of mutation for HPRT were non-significant when compared with the control group. In conclusion, the results indicated the possibility of using the changes in sister chromatid exchange as useful biomarkers for the detection of human exposure to ionizing radiation. In conclusion, the increase frequencies of sister chromatid exchange in radiation workers indicate the cumulative effect of low-level chronic exposure to ionizing radiation.

A new hybrid scheme for simulations of highly collisional RF-driven plasmas

This work describes a new 1D hybrid approach for modeling atmospheric pressure discharges featuring complex chemistry. In this approach electrons are described fully kinetically using particle-in-cell/Monte-Carlo (PIC/MCC) scheme, whereas the heavy species are modeled within a fluid description. Validity of the popular drift-diffusion approximation is verified against a ‘full’ fluid model accounting for the ion inertia and a fully kinetic PIC/MCC code for ions as well as electrons. The fluid models require knowledge of the momentum exchange frequency and dependence of the ion mobilities on the electric field when the ions are in equilibrium with the latter. To this end an auxiliary Monte-Carlo scheme is constructed. It is demonstrated that the drift-diffusion approximation can overestimate ion transport in simulations of RF-driven discharges with heavy ion species operated in the γ mode at the atmospheric pressure or in all discharge simulations for lower pressures. This can lead to exaggerated plasma densities and incorrect profiles provided by the drift-diffusion models. Therefore, the hybrid code version featuring the full ion fluid model should be favored against the more popular drift-diffusion model, noting that the suggested numerical scheme for the former model implies only a small additional computational cost.

Uncovering influence through Social Network Analysis: the role of schools in Education for Sustainable Development

This paper examines the implementation of Education for Sustainable Development (ESD) in Germany and explores the possibilities of Social Network Analysis (SNA) for uncovering influential actors in educational policy innovation processes. From the theoretical perspective, an actor’s influence is inferred from its relative position within issue-specific information flows and the trust placed in its capacities and expertise, instead of relying on an actor’s openly expressed role and policy preferences. Drawing on techniques from quantitative SNA enables to analyse the social interactions as well as the frequency and type of information exchange amongst actors in a particular issue area. Empirically, I focus my attention on the educational innovation of ESD, which has been initiated at the global level, but is mainly put into practice at the national or regional level. Data for the study come from mixed mode interviews with a standardised questionnaire. The interviews were conducted and analysed using egocentric and complete SNA. I find, amongst others results, that NGOs and governmental actors occupy significantly more central, prestigious and influential network positions than schools in the course of implementing ESD in Germany. Furthermore, school representatives exhibit few and weak relations, and mostly share links with other formal education actors.