Slowdown Rate Research Articles

Regulation of Focal Adhesion Dynamics and Cell Migration by PLC/PI3K-Mediated Metabolism of PtdIns (4,5) P2 in a Breast Cancer Cell Line.

Focal adhesions (FAs) are highly dynamic complex structures that assembled and disassembled on an ongoing basis. The balance between the two processes mediates various aspects of cell behavior, ranging from cell adhesion to cell migration. Assembly and disassembly processes of FAs are regulated by a variety of cellular signaling proteins and adaptors. We previously demonstrated that local levels of Phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) in MDA-MB-231 cells increases during FA assembly and declines during disassembly. In this study we aimed to investigate whether PtdIns(4,5)P2 regulates FA turnover. MDA-MB-231 cells were co-transfected with a labeling vinculin (or zyxin) and the PLC𝛅1-PH biosensor to visualize FA localization and PtdIns(4,5)P2 in the cell membrane. We also used pharmacological inhibitors to determine the mechanism underlying the changes of PtdIns(4,5)P2 level during FA turnover and cell migration. Immunostaining, immunoprecipitation, and Western blotting were used to examine the localization and interaction between phospholipase C (PLC)/phosphatidylinositol 3-kinase (PI3K) FA proteins. We showed that inhibition of PLC, PI3K significantly reduced the decline of PtdIns(4,5)P2 levels within FA disassembly and the slowdown rate of FA turnover and cell migration. We also showed that the inhibition of enzymes implicated in the downstream pathway of PtdIns(4,5)P2, such as diacylglycerol kinase (DAGK) and protein kinase C (PKC) significantly reduced FA turnover time and the speed of cell migration. Additionally, we demonstrated that PLC but not PI3K interact with FAs. In conclusion. This study suggests that dynamical changes of PtdIns(4,5)P2 might regulate FA turnover and facilitate cell migration.

The Regional Expressions of Secular Stagnation

This The terminology secular stagnation is suggested by Larry Summers in the last decade to demonstrate the globally economic downward trend. Although this standpoint was not paid importance at that time, the unstoppable decrease in world economy of recent years has shown this. Driven by these miscellaneous data, this report aims to search for evidence that can argue the secular stagnation. Thereby, we first analyse and select the objective tabular data from 1970s to 2010s covering all countries to apply the multiple linear regression model. Then the statistical theory is used for both preliminary measurement and subsequent regression diagnostics, also for the estimation method. In data processing, this paper explores the relationship between economic slow-down rate and (the logarithm of) affluence level with the random forest logarithm to find the threshold. Through the data visualization, the economic trend during the corresponding objective period can be observed intuitively. Finally, in the extension of the slow-down rate, we try to excavate the deep interactive terms among all countries. By the Solow growth model, it can be concluded that the gap between developing countries and developed countries is narrower due to the low original capital of poor countries. This phenomenon is also known as the catch-up effect. This report conducts the slow-down rate to verify the secular stagnation and meanwhile provides evidence for the relationship between slow-down and affluence levels.

Regional structure of mechanical engineering in Ukraine: current trends of change

The main development tendencies of machine-building production in the regions of Ukraine are examined. The paper reveals that almost all oblasts were characterized by a slowdown and uneven growth rate of machine-building production. The regional structure in terms of sales, exports, and imports of engineering products is determined. The imbalance between production and foreign trade in the regions is pointed out. Thus, the main part of machine-building industries is concentrated in the Eastern regions of Ukraine, which is due to a well-developed raw material base, established production capacity, the presence of research institutions, etc. Instead, the Western regions were the largest exporters of machine-building products among the regions, which is due to the high share of toll raw materials in machine-building production. The regional structure of mechanical engineering by types of activity is determined. The paper emphasizes that in the last years (2014-2019), production of machinery and equipment not included in other groups (33.13% of sold mechanical engineering products in 2019) was the most important sector of mechanical engineering in terms of the structure of sold products. At the same time, the production of other vehicles accounted for 25.74%, the production of motor vehicles, trailers, and semi-trailers – 1 6.05%, the production of electrical equipment – 18.22%, the production of computers, electronic, and optical products – 6.86% of sales of mechanical engineering products. The paper detects the main problems of the machine-building industry raising under the influence of external and internal factors, in particular, political and economic instability, anti-epidemic measures (due to COVID-19), low level of innovation, and obsolescence of technological base of production, etc. The directions of development of machine-building productions in the regions of Ukraine are offered, for example, to develop the mechanism of preferential lending for modernization of production, to increase the state financing of research institutes, etc.

СОПРЯЖЕННЫЕ РАСЧЕТЫ ДВИЖЕНИЯВ УПРУГОПЛАСТИЧЕСКИХ СРЕДАХ МАЛОДЕФОРМИРУЕМЫХ ТЕЛ С ОПРЕДЕЛЕНИЕМ ИХ НАПРЯЖЕННО-ДЕФОРМИРОВАННОГО СОСТОЯНИЯ

This paper presents a technology of making coupled simulations of weakly deformable bodies moving in elastoplastic environment and defining its mode of deformation. Calculation of penetration of a projectile is made by EGAK methods on a fixed calculating mesh implying that the projectile is rigid and its inner structure is unimportant. Fluid flow is calculated in a noninertial base that is connected with the stationary projectile (using BODY-3D method). Mode of deformation of the projectile is calculated on a Lagrangian mesh using software package LOGOS. Finite-element model of the projectile with the required degree of detail is used with real elastoplastic material properties of its structural parts. Loading of the projectile is implemented with an assignment of force boundary condition on its outer surface. Methods of coupling calculations and test results are provided. In this paper, it is shown that test results obtained by this developed technology are in a good agreement with direct modeling on a fixed calculating mesh. As an example of using this technology, calculation results of a penetrator-probe MoonLITE intruding into a soft soil barrier are presented. This penetrator is developed within the scope of MoonLITE mission of studying the Moon and can deepen into moon soil. Results of numerical simulations are in a good agreement with the experimental data, maximum difference for average slow-down rate of the penetrator is 10–15%.

The 2016 glitch in the Vela pulsar

We report the detection of a glitch event in the Vela pulsar, which occurred on 12 December 2016, based on the timing data obtained from observations between January 2016 and February 2018 at frequency centered at 2256 MHz using the Kunming 40-m radio telescope. The timing solutions for the pre- and post-glitch are presented. By fitting the glitch model to the timing data, we found that the post-glitch recovery exhibits two terms with exponential decay with the time scales of 1 d and 6 d, respectively. The glitch parameters are determined with g/=1.431(2)x10-6 and g/=73.354x10-3. The value of the coupling parameter is calculated to be approximate to 0.08, implying that the core superfluid is probably not involved in this event. For the glitches with two or more terms with exponential decay in the Vela pulsar, we show that the exponential decays usually exhibit longer time scales with higher degree of glitch recovery. The post-glitch behavior in the slow-down rate is dominated by a linear decrease process. From detection of the variations in the slopes of the spin-down rates after the exponential recoveries of the 2013 and 2016 glitches, we conclude that no persistent shift was involved in the 2016 glitches.

Core rotation braking on the red giant branch for various mass ranges

Context. Asteroseismology allows us to probe stellar interiors. In the case of red giant stars, conditions in the stellar interior are such as to allow for the existence of mixed modes, consisting in a coupling between gravity waves in the radiative interior and pressure waves in the convective envelope. Mixed modes can thus be used to probe the physical conditions in red giant cores. However, we still need to identify the physical mechanisms that transport angular momentum inside red giants, leading to the slow-down observed for red giant core rotation. Thus large-scale measurements of red giant core rotation are of prime importance to obtain tighter constraints on the efficiency of the internal angular momentum transport, and to study how this efficiency changes with stellar parameters. Aims. This work aims at identifying the components of the rotational multiplets for dipole mixed modes in a large number of red giant oscillation spectra observed by Kepler. Such identification provides us with a direct measurement of the red giant mean core rotation. Methods. We compute stretched spectra that mimic the regular pattern of pure dipole gravity modes. Mixed modes with the same azimuthal order are expected to be almost equally spaced in stretched period, with a spacing equal to the pure dipole gravity mode period spacing. The departure from this regular pattern allows us to disentangle the various rotational components and therefore to determine the mean core rotation rates of red giants. Results. We automatically identify the rotational multiplet components of 1183 stars on the red giant branch with a success rate of 69% with respect to our initial sample. As no information on the internal rotation can be deduced for stars seen pole-on, we obtain mean core rotation measurements for 875 red giant branch stars. This large sample includes stars with a mass as large as 2.5 M⊙, allowing us to test the dependence of the core slow-down rate on the stellar mass. Conclusions. Disentangling rotational splittings from mixed modes is now possible in an automated way for stars on the red giant branch, even for the most complicated cases, where the rotational splittings exceed half the mixed-mode spacing. This work on a large sample allows us to refine previous measurements of the evolution of the mean core rotation on the red giant branch. Rather than a slight slow-down, our results suggest rotation is constant along the red giant branch, with values independent of the mass.

Detection of long nulls in PSR B1706−16, a pulsar with large timing irregularities

Single pulse observations, characterizing in detail, the nulling behaviour of PSR B1706$-$16 are being reported for the first time in this paper. Our regular long duration monitoring of this pulsar reveals long nulls of 2 to 5 hours with an overall nulling fraction of 31$\pm$2\%. The pulsar shows two distinct phases of emission. It is usually in an active phase, characterized by pulsations interspersed with shorter nulls, with a nulling fraction of about 15 \%, but it also rarely switches to an inactive phase, consisting of long nulls. The nulls in this pulsar are concurrent between 326.5 and 610 MHz. Profile mode changes accompanied by changes in fluctuation properties are seen in this pulsar, which switches from mode A before a null to mode B after the null. The distribution of null durations in this pulsar is bimodal. With its occasional long nulls, PSR B1706$-$16 joins the small group of intermediate nullers, which lie between the classical nullers and the intermittent pulsars. Similar to other intermediate nullers, PSR B1706$-$16 shows high timing noise, which could be due to its rare long nulls if one assumes that the slowdown rate during such nulls is different from that during the bursts.

Anaerobic degradation of 2-propanol: Laboratory and pilot-scale studies

The anaerobic degradation of 2-propanol, an important industrial solvent, was scaled-up from batch assays to a pilot expanded granular sludge bed (EGSB) reactor at 25°C. Batch studies indicated that 2-propanol followed Haldane kinetics, with a maximum rate at 10gCODL−1. Concentrations as high as 25gCODL−1 did not inhibit the degradation of ethanol, a common co-solvent. Similar specific methanogenic activities (SMA) were obtained for water-solvent and water-brewery sludges (88 and 77mlCH4g-VS−1d−1 at 5gCODL−1). Continuous degradation showed a lag-phase of three weeks with water-brewery sludge. Increases in 2-propanol load from 0.05 to 0.18kgCODkg-VS−1d−1 caused a shift from the consumption of soluble matter to methane production, indicating polyhydroxybutyrates (PHB) accumulation. Conversely, smooth increases of up to 0.29kgCODkg-VS−1d−1 allowed 2-propanol degradation without PHB accumulation. The slowdown rate of 2-propanol-oxidizer and acetate-utilizing methanogen bacteria below 20°C adversely impacted both removal and CH4 yield.

Procedure for Calculating On-Time Duration of the Main Cycle of a Set of Coordinated Traffic Lights

Abstract The task of enhancing efficiency of traffic lights operation demands optimization of the throughput capacity of a regulated street and road network junction including rational and full use of an operation cycle of traffic lights. Oftentimes, the existing calculation system for an operation cycle of traffic lights at intersections does not provide a jam-free and safe route for transport in rush hours. In this article the authors suggest a new calculation methodology for an operation cycle of traffic lights based on the expert calculation which considers the necessity for keeping the possibility of entering a crossing by all vehicles that have arrived to a crossing from each of conflicting directions (including the most loaded one) during one cycle; the use of vehicles slow-down rate called in the traffic rules as “without emergency braking”; the use of phase coefficients at the calculation of the main cycles of the less loaded directions.

VM Capacity-Aware Scheduling within Budget Constraints in IaaS Clouds.

Recently, cloud computing has drawn significant attention from both industry and academia, bringing unprecedented changes to computing and information technology. The infrastructure-as-a-Service (IaaS) model offers new abilities such as the elastic provisioning and relinquishing of computing resources in response to workload fluctuations. However, because the demand for resources dynamically changes over time, the provisioning of resources in a way that a given budget is efficiently utilized while maintaining a sufficing performance remains a key challenge. This paper addresses the problem of task scheduling and resource provisioning for a set of tasks running on IaaS clouds; it presents novel provisioning and scheduling algorithms capable of executing tasks within a given budget, while minimizing the slowdown due to the budget constraint. Our simulation study demonstrates a substantial reduction up to 70% in the overall task slowdown rate by the proposed algorithms.

Intelligent Water Drop Algorithm Based Particle Swarm Optimization (IWDPSO) Towards Multi Objective Job Scheduling for Grid Computing

The development of a huge amount of client’s job for equivalent performance on open-resource grid system is the main reason of system failures or delayed process due to grimy hardware, software vulnerability, as well as shared confined policy. In this study we represent highly reliability conditions in grid work scheduling and present a new procedure for scheduling by hybridization of intelligent water drop algorithm and particle swarm optimization technique and compare it with earliest deadline in the basis of first come first served. The IWDPSO algorithm is tested with two datasets namely Numerical Aerodynamic Simulation (NAS) and Parameter Sweep Application (PSA) and the results are tested with performance metrics makespan, slowdown and failure rate and grid utilization. The proposed algorithms results in effective usage of grid computing resources with reduced makespan, slowdown and failure rate. The proposed algorithm is compared with Risky-MinMin (RMM), Preemptive-MinMin (PMM) and Delay Tolerant Space-Time Genetic Algorithm (DTSTGA).

45 years of rotation of the Crab pulsar

The 30-Hz rotation rate of the Crab pulsar has been monitored at Jodrell Bank Observatory since 1984 and by other observatories before then. Since 1968, the rotation rate has decreased by about 0.5 Hz, interrupted only by sporadic and small spin-up events (glitches). 24 of these events have been observed, including a significant concentration of 15 occurring over an interval of 11 yr following MJD 50000. The monotonic decrease of the slowdown rate is partially reversed at glitches. This reversal comprises a step and an asymptotic exponential with a 320-d time constant, as determined in the three best-isolated glitches. The cumulative effect of all glitches is to reduce the decrease in slowdown rate by about 6 per cent. Overall, a low mean braking index of 2.342(1) is measured for the whole period, compared with values close to 2.5 in intervals between glitches. Removing the effects of individual glitches reveals an underlying power-law slowdown with the same braking index of 2.5. We interpret this value in terms of a braking torque due to a dipolar magnetic field in which the inclination angle between the dipole and rotation axes is increasing. There may also be further effects due to a monopolar particle wind or infalling supernova debris.

Spatially Varying Determinants of Farmland Conversion Across Qiantang Watershed, China

This paper employed geographically weighted regression (GWR) to characterize the determinants of farmland conversion at administrative scale between 1994 and 2003 across Qiantang watershed, China. Six determinants were identified: total area of forest, distance to highway, distance to second road, distance to river, population, and gross domestic product. Relationships between these identified determinants and farmland conversion showed great spatial non-stationarity, since their character, nature, and strength varied significantly across space. Typically, for cities whose development was heavily relied on road infrastructure development, the impacts of "distance to second road" and "distance to river" was negative. However, in mountainous areas, the restriction of terrain factors led to positive impacts from these two variables. For areas undergoing rapid socio-economic development, farmland conversion was accelerated by population growth and economic development. However, for more urbanized regions, a slow-down rate of farmland conversion would be expected. Our study highlighted that the problem of spatial non-stationarity should be addressed when qualifying the determinants of farmland conversion. Linking our results within the context of farmland protection, we argue that implementing local-specific land management practices, instead of the current one-size-fits-all framework, is the key for the success of farmland protection in China.

Detection of 107 glitches in 36 southern pulsars

Timing observations from the Parkes 64-m radio telescope for 165 pulsars between 1990 and 2011 have been searched for period glitches. Data spans for each pulsar ranged between 5.3 and 20.8 yr. From the total of 1911 yr of pulsar rotational history, 107 glitches were identified in 36 pulsars. Out of these glitches, 61 have previously been reported whereas 46 are new discoveries. Glitch parameters, both for the previously known and the new glitch detections, were measured by fitting the timing residual data. Observed relative glitch sizes Δνg/ν range between 10−10 and 10−5, where ν = 1/P is the pulse frequency. We confirm that the distribution of Δνg/ν is bimodal with peaks at approximately 10−9 and 10−6. Glitches are mostly observed in pulsars with characteristic ages between 103 and 105 yr, with large glitches mostly occurring in the younger pulsars. Exponential post-glitch recoveries were observed for 27 large glitches in 18 pulsars. The fraction Q of the glitch that recovers exponentially also has a bimodal distribution. Large glitches generally have low Q, typically just a few per cent, but large Q values are observed in both large and small glitches. Observed time constants for exponential recoveries ranged between 10 and 300 d with some tendency for longer time-scales in older pulsars. Shorter time-scale recoveries may exist but were not revealed by our data which typically have observation intervals of 2–4 weeks. For most of the 36 pulsars with observed glitches, there is a persistent linear increase in |$\dot{\nu }$| (i.e. decrease in the slow-down rate |$|\dot{\nu }|$|⁠) in the interglitch interval. Where an exponential recovery is also observed, the effects of this are superimposed on the linear increase in |$\dot{\nu }$|⁠. In some but not all cases, the slope of the linear recovery changes at the time of a glitch. The |$\ddot{\nu }$| values characterizing the linear changes in |$\dot{\nu }$| are almost always positive and, after subtracting the magnetospheric component of the braking, are approximately proportional to the ratio of |$|\dot{\nu }|$| and the interglitch interval, as predicted by vortex-creep models.

29 glitches detected at Urumqi Observatory

Glitches detected in pulsar timing observations at the Nanshan radio telescope of Urumqi Observatory between 2002 July and 2008 December are presented. In total, 29 glitches were detected in 19 young pulsars, with this being the first detection of a glitch in 12 of these pulsars. Fractional glitch amplitudes range from a few parts in 10−11 to 3.9 × 10−6. Three ‘slow’ glitches are identified in PSRs J0631+1036, B1822−09 and B1907+10. Post-glitch recoveries differ greatly from pulsar to pulsar and for different glitches in the same pulsar. Three small glitches in PSRs B0402+61, B0525+21 and J1853+0545 show evidence for normal post-glitch recovery, but for PSRs B0144+59 and B2224+65 the spin frequency ν continually increases relative to the pre-glitch solution for hundreds of days after their small glitches. Most large glitches show some evidence for exponential post-glitch recovery on time-scales of 100–1000 d, but in some cases, e.g. PSR B1758−23, there is little or no recovery, i.e. no detectable increase in at the time of the glitch. Beside exponential recoveries, permanent increases in slowdown rate are seen for the two large glitches in PSRs B1800−21 and B1823−13. These and several other pulsars also show a linear increase in following the partial exponential recovery, which is similar to the Vela pulsar post-glitch behaviour. However, the rate of increase, ⁠, is an order of magnitude less than for the Vela pulsar. We present improved positions for 14 of the glitching pulsars. Analysis of the whole sample of known glitches shows that fractional glitch amplitudes are correlated with characteristic age with a peak at about 105 yr, but there is a spread of two or three orders of magnitude at all ages. Glitch activity is positively correlated with spin-down rate, again with a wide spread of values. For some (but not all) pulsars, there is a correlation between glitch amplitude and the duration of the following interglitch interval. In no case is there a correlation of glitch amplitude with the duration of the preceding interglitch interval.

Unusual glitch activity in the RRAT J1819−1458: an exhausted magnetar?

We present an analysis of regular timing observations of the high-magnetic-field Rotating Radio Transient (RRAT) J1819$-$1458 obtained using the 64-m Parkes and 76-m Lovell radio telescopes over the past five years. During this time, the RRAT has suffered two significant glitches with fractional frequency changes of $0.6\times10^{-6}$ and $0.1\times10^{-6}$. Glitches of this magnitude are a phenomenon displayed by both radio pulsars and magnetars. However, the behaviour of J1819$-$1458 following these glitches is quite different to that which follows glitches in other neutron stars, since the glitch activity resulted in a significant long-term net decrease in the slow-down rate. If such glitches occur every 30 years, the spin-down rate, and by inference the magnetic dipole moment, will drop to zero on a timescale of a few thousand years. There are also significant increases in the rate of pulse detection and in the radio pulse energy immediately following the glitches.

Inner core wobble and free core nutation of pulsar PSR B1828-11

PSR B1828-11 has long-term, highly periodic and correlated variations in pulse shape and a slow-down rate with period variations of approximately 1000, 500 and 250 days [Stairs, I.H., Lyne, A.G., Shemar, S.L. Evidence for free precession in a pulsar. Nature 406, 484–486, 2000]. There are three potential explanations of pulses time-of-arrival from a pulsar. These are related to the interior of the neutron star, planetary bodies, free precession and nutation. We use the Hamiltonian canonical method of Getino (1995) for analyzing the dynamically symmetric pulsar PSR B1828-11, consisting of a rigid crust, elliptical liquid outer core and solid inner core. Using the theory of differential rotation of a pulsar, we investigate the dependence on Chandler wobble period, inner core wobble, retrograde free core nutation and prograde free inner core nutation from ellipticity of the inner crystal core, outer liquid core and total pulsar.

Unusual glitch behaviours of two young pulsars

In this paper we report unusual glitches in two young pulsars, PSR J1825-0935 (B1822-09) and PSR J1835-1106. For PSR J1825-0935, a slow glitch characterized by a temporary decrease in the slow-down rate occurred between 2000 December 31 and 2001 December 6. This event resulted in a permanent increase in frequency with fractional size Deltanu/nu similar to 31.2( 2) x 10(-9); however, little effect remained in the slow-down rate. The glitch in PSR J1835-1106 occurred abruptly in 2001 November (MJD 52 220 +/- 3) with Deltanu/nu similar to 14.6(4) x 10(-9) and little or no change in the slow-down rate. A significant change in nu apparently occurred at the glitch with nu having opposite sign for the pre- and post-glitch data.

PSR J1847-0130: A Radio Pulsar with Magnetar Spin Characteristics

We report the discovery of PSR J18470130, a radio pulsar with a 6.7 s spin period, in the Parkes Multibeam Pulsar Survey of the Galactic plane. The slowdown rate for the pulsar, s s 1 , is high and implies a 12 1.3 # 10 surface dipole magnetic field strength of G. This inferred dipolar magnetic field strength is the highest 13 9.4 # 10 by far among all known radio pulsars and over twice the “quantum critical field” above which some models predict radio emission should not occur. The inferred dipolar magnetic field strength and period of this pulsar are in the same range as those of the anomalous X-ray pulsars, which have been identified as being “magnetars” whose luminous X-ray emission is powered by their large magnetic fields. We have examined archival ASCA data and place an upper limit on the X-ray luminosity of J18470130 that is lower than the luminosities of all but one anomalous X-ray pulsar. The properties of this pulsar prove that inferred dipolar magnetic field strength and period cannot alone be responsible for the unusual high-energy properties of the magnetars and create new challenges for understanding the possible relationship between these two manifestations of young neutron stars. Subject headings: pulsars: individual (PSR J18470130) — stars: magnetic fields — stars: neutron — X-rays: stars

What determines the strength and the slowdown rate of bars?

Isolated barred galaxies evolve by redistributing their angular momentum, which, emitted by material in the inner disc at resonance with the bar, can be absorbed by resonant material in the outer disc, or in the halo. The amount of angular momentum that can be emitted/absorbed at a given resonance depends on the distribution function of the emitting/absorbing material. It thus depends not only on the amount of material on resonant orbits, but also on the velocity dispersion of that material. As it loses angular momentum, the bar becomes stronger and it also rotates slower. Thus the strength of the bar and the decrease of its pattern speed with time are set by the amount of angular momentum exchanged within the galaxy, which, in turn, is regulated by the mass distribution and the velocity dispersion of the material in the disc and spheroidal components. Correlations between the pattern speed of the bar, its strength and the angular momentum absorbed by the spheroid (halo plus bulge) argue strongly that it is the amount of angular momentum exchanged that determines the strength and the slowdown rate of the bar. The decrease of the bar pattern speed with time should not be used to set constraints on the halo-to-disc mass ratio, since it depends also on the velocity dispersion of the halo and disc material.