Successive Time Interval Research Articles

Larvicidal potency of Spatholobus parviflorus (DC.) Kuntze against Aedes albopictus (Diptera: Culicidae).

Aedes albopictus (Diptera: Culicidae) is one well-established vector of a series of mosquito-borne diseases. The larval stage of their life cycle is best suited to control a large population of mosquitoes easily. Controlling the larval stage of such vectors can also control the spread of the pandemic disease through the vector. Larvicides, which are synthetic, is a promising solution now. This kind of synthetic larvicides affects humans and animals equally and damages the environment through unscientific and widespread use. Beyond that, their continued use could create selection pressure and, thus, a resistant population. Plant-based larvicide is a way to overcome the shortcomings of synthetic larvicides. This study infers the larvicidal potency of Spatholobus parviflorus (DC.) Kuntze solvent extracts (SPSE) and crude water extracts (SPWE) against Aedes albopictus, using the dose-response larvicidal assay. The assay conducted using different concentrations of extract (0.1, 0.2, 0.3, 0.4, and 0.5%) and standard (bleaching powder), with the concentrations 0.01, 0.02, 0.03, 0.04 and 0.05%. The nourishment of the larvae is maintained by supplementing each of the Petri plates with 10 mg of larval food. The mortality of the nascent is recorded in a successive time interval of 12 h, up to 72 h. A significant (P<0.05) mortality was observed in SPWE of the leaf. The observed data analyses using Log probit analysis, and the highest LC50 (lethal concentration to kill 50% of the population), 0.57 mg/ml, is observed at the 24th h of the larvicidal assay. The lowest LC50, 0.35 mg/ml is observed at the 60th h of the larvicidal assay. In conclusion, the results show that S. parviflorus leaf water extract (SLWE) has significant larvicidal activity against A. albopictus, and this is the first account for the larvicidal potency of S. parviflorus. The study concludes that S. parviflorus is an excellent candidate plant for the development of a plant-based larvicide. This possibly influences a reduction in the use of typical household bleach and conventional chemical larvicides.

A start-up optimization strategy of a hydroelectric generating system: From a symmetrical structure to asymmetric structure on diversion pipes

This study focuses on the start-up optimization strategies for a Hydroelectric Generating System (HGS). A mathematical model of HGS to describe the complex hydraulic coupling relationship, between the water diversion pipes, the hydro-turbine, the governor and the generator, is proposed. This allows to accurately describe the start-up process and identifying the effect of successive start-up time interval (ΔT) and the pipe structure on the water head and the rotational speed of HGS. The result shows that the successive start-up strategy with ΔT = 9s maximally reduces the water head fluctuation of units #1 and #2 by 30.94% and 25.77% compared with the simultaneous start-up strategy when the branch pipe is symmetric. For the asymmetric branch pipe, the unit behind branch B# starts up first is beneficial to reduce the water head fluctuation of the unit behind branch #A when the flow inertia time constant of branch #A is larger. Finally, the parameters of the start opening as well the PID governor parameters are optimized by a multi-objective particle swarm optimization for the asymmetric pipe in order to minimize the unit speed overshoot and the speed rise time. These results in this work provide a theoretical guidance for the selection of optimal start-up strategy in the case of symmetric and asymmetric HGS branch pipe structures.

Effect of Time Interval on Arsenic Toxicity to Paddy Field Cyanobacteria as Evident by Nitrogen Metabolism, Biochemical Constituent, and Exopolysaccharide Content.

Arsenic poisoning in aquatic ecosystem is a global concern that obstructs the productivity of agricultural lands (paddy fields) by targeting the growth of cyanobacteria. The cyanobacteria also tolerate and accumulate elevated concentration of arsenic (As) inside the cell and excrete out from cells in less toxic forms after the successive time interval. Thus to validate this, the study was carried out at two different time intervals, i.e., 48 h and 96 h. Two redox forms of As arsenate (AsV) and arsenite (AsIII) at different concentrations (50, 100, and 150 mM AsV; 50, 100, and 150 μM AsIII) caused substantial reduction in growth, pigments (Chl a/Car and phycobiliproteins: phycocyanin, allophycocyanin, and phycoerythrin), inorganic nitrogen ( nitrate (NO3-) and nitrite (NO2-)) uptake, activity of enzymes (NR, NiR, GS, and GOGAT) of nitrogen metabolism, biochemical constituents (protein, carbohydrate, and exopolysaccharide (EPS) contents of Nostoc muscorum, and Anabaena sp. PCC7120. The tested doses of AsV and AsIII after 48 h of exposure exhibited adverse impact on these parameters, but after 96 h with lower doses of AsV (50 mM and 100 mM) and AsIII (50 μM and 100 μM), significant recovery was recorded. Contrary to this, at higher dose of AsV (150 mM) and AsIII (150 μM), the adverse impact was further aggravated with increasing time exposure. Contrary to the activity of NR, NiR, GS, and GOGAT, GDH activity (alternative NH3+ assimilating enzyme) was found to increase, and after 96 h, the activity showed declining trend but still higher than the control. The biochemical constituent EPS (first protective barrier) under scanning electron microscope showed more accumulation of dry adsorbent in the case of AsIII stress hence displayed more toxic nature of AsIII than AsV. The study concludes that with increasing time exposure, the recovery in growth and related parameters mainly at lower doses of AsV and AsIII points toward adaptability of cyanobacteria which was more pronounced in Nostoc muscorum.

Kinetic study of extrusion cooking of corn-rice flour blend fortified with nutraceutical concentrates with respect to various physical parameters

PurposeThe purpose of this paper is to investigate the effect of residence time distribution in extruders along with the incorporation of nutraceuticals on the final quality of the products with respect to several pivotal responses.Design/methodology/approachCorn–rice flour blend fortified with isolated nutraceutical concentrates at two (low and high) levels was extruded at barrel temperature (110°C), screw speed (260 rpm) and feed moisture (17 percent). Extrudates were collected at an interval of 24 s followed by analysis for radial expansion (RE), bulk density (BD), water absorption index (WAI), sensory score (SS), textural hardness, colorimetric values (L*, a* and b*) and color difference (E).FindingsThe entire data were fitted to zero- and first-order kinetic models. There was a gradual decrease in RE, SS and L* value, whereas an increase in BD, textural hardness and a* value of extrudates fortified with the three nutraceutical concentrates was observed with the successive time interval of 24 s along with a more pronounced effect on color difference (E) observed during the last stages of extrusion time. The zero-order kinetic model was well fitted for BD and a* value, whereas the first-order kinetic model showed better results for RE, WAI, SS, textural hardness, L* value, a* value and b* value of fortified extrudates.Originality/valueNutraceuticals like β-glucans, lignans and γ oryzanol exhibit numerous health-beneficial effects. This study analyzes the kinetics of changes in various responses of extrudates fortified with these nutraceutical concentrates during extrusion.

Optimal successive start-up strategy of two hydraulic coupling pumped storage units based on multi-objective control

This paper aims to study the optimal successive start-up strategy of two hydraulic coupling pumped storage units (PSUs) based on multi-objective control. Firstly, a successive start-up model of a pumped storage power station (PSPS) with two PSUs is established. Secondly, the analysis of the impact of successive time interval ΔT is carried out. Thirdly, a novel optimization scheme multi-objective with two PSUs owning different parameters (MODP) is proposed for start-up optimization. For comparison, three optimization schemes named single objective with two PSUs sharing the same parameters (SOSP), single objective with two PSUs owning different parameters (SODP) and multi-objective with two PSUs sharing the same parameters (MOSP) are also tested. Finally, according to the four optimization schemes, i.e. SOSP, SODP, MOSP and MODP, the optimization model is established and performed separately in MATLAB 9.1 based on a real case. The results indicate that the change of ΔT has a great effect on the transient process of 1# PSU, but less effect on the transient process of 2# PSU. ΔT should be chosen as a decision variable in the successive start-up optimization. For the successive start-up of a PSPS with two PSUs, the multi-objective scheme is superior to the single-objective scheme. The scheme of different parameters is superior to the scheme of sharing parameters. Among four schemes, MODP scheme is the best. The MODP scheme can obtain the Pareto Set that provides more choices for decision makers, which is flexible in engineering applications. MODP is a general method for successive start-up strategy optimization.

An extended geometric process repairable model with its repairman having vacation

In this paper, a new single component repairable system model with a repairman is proposed. Assume that the successive working time interval of the component and the successive repair time interval after repair is described by the extended geometric process. The repairman has multiple vacation when the component is working, and component is repaired delayed with a given probability when it fails. The component will work again when it repaired. Under the assumption, the explicit expression of the long-run average cost rate function of the system based on the failure number of the component is derived. Numerical cases are designed to illustrate the long-run average cost rate function of the proposed model. Finally, sensitive analysis of parameters is carried out.

Predicting search time when hunting for multiple moving targets: A recursive harmonic law.

We investigate searching for multiple mobile objects on networks and introduce the concept of mean random search time (MRST) to quantify the expected time a searcher takes to capture moving targets specified in advance. We consider this quantity averaged over all initial conditions for a searcher and multiple targets called the global MRST. We find that the growth of global MRST follows a recursive harmonic law with respect to that of stalking the individuals. In particular, when the diffusive laws of moving targets are identical, the global MRST shows a logarithmic increase with the number of moving targets. Moreover, utilizing the recursive harmonic law, we can accurately predict the expected successive time interval for capturing a new moving target. The recursive harmonic law unveils the underlying mechanism governing the search time when hunting for multiple moving targets on networks.

The Effect of Pre-Existing Standards and Regulations on the Development and Diffusion of Radically New Innovations

The controversy among scientists on whether standards and regulations hamper or stimulate innovation contains too little specificity and provides too few clues for innovation managers to act upon. In this article, we underscore the importance of timing and start by focusing on the effect of pre-existing standards and regulations on the subsequent development and diffusion of product innovations. The effect is assessed in terms of the time interval between the invention of a technological principle and the introduction of the first marketable product (development phase), and the successive time interval up to the start of large-scale industrial production and diffusion (adaptation phase). The authors analyse fifty heterogeneous cases studies of radically new high-tech product innovations from the year 1850 onward. The results indicate that pre-existing standards and regulations significantly shorten the adaptation phase of innovations, an effect not found for the development phase. The shortening effect on the adaptation phase is particularly evident for radically new innovations and innovations that are an integral part of larger technological systems. As the adaptation phase is often a time- and capital-intensive phase for industry, this accelerating effect on the diffusion of innovations is highly relevant for innovation managers and policy makers.

Response of the two-dimensional kinetic Ising model under a stochastic field

We study, using Monte Carlo dynamics, the time (t) dependent average magnetization per spin m(t) behavior of the 2D kinetic Ising model under a binary (±h0) stochastic field h(t). The time dependence of the stochastic field is such that its average over each successive time interval τ is assured to be zero (without any fluctuation). The average magnetization is considered as an order parameter of the system. The phase diagram in (h0,τ) plane is obtained. Fluctuations in the order parameter and their scaling properties are studied across the phase boundary. These studies indicate that the nature of the transition is Ising like (static Ising universality class) for field amplitudes h0 below some threshold value (dependent on τ values; as τ → ∞ across the phase boundary). Beyond these , the transition is no longer continuous.

A comparitive study on cryo, pulsed ultrasound and its combination therapies on delayed onset of muscle soreness

Objectives: Individuals engage in strenuous physical activity to which they are unaccustomed usually land up in a phenomenon called Delayed Onset of Muscle Soreness (DOMS) and results in pain, muscle stiffness and swelling. The current study was aimed to see the effect of cryo , ultrasound and its combination therapies on the reduction of symptoms of DOMS. Materials and Methods: A total of 30 subjects with the mean age of 22.1 ± 5.9 years participated in the study. Subjects were randomly allocated to three groups A, B and C (n=10) and induced DOMS by a standard exercise protocol. Each group received different treatment application i.e. ultrasound (US), cryotherapy (CT) and combination (C) of both. Study outcomes were measured by Perceived Muscle Soreness (PMS), Relaxed-Elbow flexion angle (rEFA), Plasma Creatine Kinase (CK) level at 0 hours (pre -exercise), 24hrs, 48hrs, 72hrs and at 92hrs. Results: All three groups showed improvement with respect to their interventions, whereas the C group, after 96 hours of post-exercise the rEFA return to its near normal range as compared to the other two groups. Although there was a rise in the plasma CK level in all three groups, however the C group was effective in minimizing the rising level of CK and also in the reduction of muscle soreness at successive time interval s and reaches to baseline after 96 hours of post -exercise. Conclusion: The combined application of cryotherapy and pulsed ultrasound immediately after exercise induced muscle damage is a better choice of treatment , It is also observed that cryotherapy was more effective than pulsed ultrasound alone treatment in reduction of symptoms.

New Mathematical Model to Estimate Road Traffic Noise in View of the Appearance Rate of Heavy Vehicles

A new mathematical model is proposed to estimate road traffic noise at sites along a freeway where the traffic volume fluctuates from a maximum of 900 vehicles per hour in the daytime to a minimum of 300 vehicles per hour at night. The model considers traffic conditions such as the percentage of heavy vehicles, time interval between successive (two or more) heavy vehicles and measurement time interval. The A-weighted equivalent continuous sound pressure levels calculated from this model are in keeping with measured ones at several representative time intervals both in the daytime and nighttime.

Long-term outcome and toxicity in a Phase I/II trial using high-dose-rate multicatheter interstitial brachytherapy for T1/T2 breast cancer

Purpose To present an updated analysis of survival, recurrence rate, and toxicity for a cohort of women with early-stage breast cancer treated with high-dose-rate interstitial brachytherapy for accelerated partial breast irradiation. Methods and materials From August 1997 to July 2001, a total of 32 women with 33 breast cancers were treated with interstitial high-dose-rate brachytherapy after breast-conserving surgery as part of a Phase I/II protocol. All patients had T1–2 tumors with ≤3 axillary nodes positive, nonlobular histology, negative surgical margins, and no evidence of extracapsular lymph node extension. Multiple brachytherapy catheters were used and radiation was delivered with a high activity (3–10 Ci) 192Ir source placed via remote after loader. Dose was prescribed to the tumor bed plus a 2 cm margin. A total of 3400 cGy was delivered in 10 fractions of 340 cGy each given twice daily over 5 days. Toxicities (skin, subcutaneous tissue, pain, fat necrosis) were evaluated by Radiation Therapy Oncology Group criteria; cosmesis was assessed using a previously published scale. Toxicity scores were separated into four followup intervals: ≤6 months, >6 months and ≤2 years, >2 and ≤5 years, and >5 years. Results The actuarial local recurrence rate was 6.1% at 5 years with the last measured event at 70.5 months. A total of three treatment failures were observed at 25.8, 39.9, and 70.5 months of followup. All three were elsewhere failures within the treated breast. One patient died after 90.0 months of followup secondary to a subsequently diagnosed small-cell lung cancer. For the purpose of analysis, toxicity scores were assigned to each of four followup intervals: ≤6 months, >6 but ≤24 months, >24 but ≤60 months, and >60 months. Fat necrosis was not seen in the first 6 months after treatment, then appeared in 27.3% of patients from 6 to 24 months, 28.1% from 24 to 60 months, and 17.9% beyond 60 months. Skin toxicity appeared to stabilize with longer followup: the percentage of patients showing any degree of skin toxicity was 69.7%, 33.3%, 40.6%, and 28.6% at each successive time interval. Subcutaneous toxicity increased beyond 60 months: moderate to severe subcutaneous toxicity was seen in 15.2%, 18.2%, 18.8%, and 35.7% of patients successively. The percentage of patients with less than excellent cosmetic outcome improved beyond 60 months (21.2%, 21.2%, 21.9%, and 11.1% successively). Only 1 patient experienced more than mild pain at any time. The percentage of patients experiencing any degree of pain improved over time (30.3%, 33.3%, 18.8%, 17.9%). Conclusions Our series showed a local recurrence rate of 6.1% at 5 years, which is comparable to that seen in conventional whole breast series. Fat necrosis was found in more than half the cohort. Fat necrosis, pain, and cosmesis appeared to improve with longer followup, whereas subcutaneous toxicity worsened and skin toxicity stabilized.

Improvement in renal function after left ventricular assist device placement

Background: Worsening renal function is a common consequence of heart failure (HF), and may be improved with circulatory support. The efficacy of left ventricular assist device (LVAD) support to reverse renal insufficiency in end-stage HF has not previously been quantitatively reported, and would be useful to aid in decision-making regarding utilization of LVAD support in the context of bridge-to-transplant (BTT) and destination therapy. Methods: We addressed this question using data derived from 220 patients who underwent Novacor LVAD placement from 1996–03 (190 for BTT and 30 as destination therapy). Creatinine clearance (CrCl), calculated using the Cockroft-Gault formula, was compared among all surviving hospitalized patients who had renal function assessed pre-operative (n=220), at 1 (n=203), 2 (n=178), 3 (n=81), and 4 weeks (n=82) after implant. Paired (same patient, different date) sample t test analyses were then performed for each successive time interval. Similar analyses were performed for patients with baseline CrCl <50 ml/min. Results: Baseline serum creatinine was 1.6±0.7 mg/dl; 60 of patients had CrCl <50 ml/min at implant. Creatinine clearance rose significantly within the first week in the overall study population, from 76.6±46.1 ml/min to 91.8±51.2 ml/min at one week and to 114.9±63.8 ml/min by three weeks. Secondary analysis evaluated patients for whom both pre- and post-implant values were available. This paired sample analysis showed a similar effect (77.0±46.6 pre-implant, rising to 92.1±51.1 ml/min at week 1 (n=202;p<0.01), and from 89.4±49.2 to 95.2±52.4 ml/min (n=171;p=0.01) between weeks 1 and 2. Similar analysis among those with baseline CrCl <50 ml/min showed that the CrCl rose from 36.7±9.2 to 60.1±35.5 (n=55; p<0.01) from pre-implant to week 1 and from 59.7±36.8 to 66.8±47.3 ml/min (n=47; p=0.15) from week 1 to 2. Thirty-seven of the 60 patients with CrCl <50 ml/min (62%) on intra-aortic balloon pump support pre-implant also showed significant improvement in CrCl after LVAD implantation. Overall, 41 of 60 patients (68%) with CrCl <50 improved their creatinine clearance to >50 ml/min during the first 4 weeks after surgery. Conclusion: In patients selected for bridge or destination LVAD support, majority of the patients who demonstrate renal insufficiency that would exclude them from traditional transplant candidacy on the day of LVAD implantation, exhibited substantial improvement in renal function over the first month after device implantation.

How Does Time‐Dependent Dental Unit Waterline Flushing Affect Planktonic Bacteria Levels?

The purpose of this study was to evaluate how time-dependent waterline flushing affects the presence of biofilm in otherwise-untreated dental unit waterlines (DUWLs). Water samples were obtained from twelve highspeed handpiece DUWLs located in the undergraduate treatment clinic at the University of Missouri-Kansas City, School of Dentistry. Baseline water samples (50 cc) were collected prior to the start of continuous flushing. Additional 50 cc samples were collected after two-, three-, and four-minute flushing intervals from the baseline. The levels of planktonic bacteria in DUWLs were quantified by counting colony forming units (CFUs). In addition, segments of water tubing from each of the highspeed handpiece waterlines were examined by scanning electron microscopy, which confirmed the presence of a residual biofilm in the lumen of each dental unit waterline. A one-factor repeated measures ANOVA showed a statistically significant (p<0.01) reduction in CFUs at all intervals compared to baseline and between each successive time interval. Indeed, after four minutes of continuous flushing, all waterlines still harbored CFU levels that exceed current American Dental Association (ADA) recommendations. It was concluded that water flushing of DUWLs produced a statistically significant reduction in planktonic bacteria at each time interval compared to the baseline and between each successive time interval. However, the level of CFUs after four minutes of continuous water flushing still exceeds the current ADA recommendations for acceptable levels of microorganisms.

Practical hybrid adaptive control taking into consideration computational time

Abstract This paper presents a practical design for hybrid adaptive control which does not need any numerical integration and is not destabilized by computational delays for parameter estimation. The controller consists of two simultaneously executing parts, that is, a control part and an estimation part. The estimation part searches the maximum estimation error over a successive time interval repeatedly. Based on this maximum error, the estimators for the unknown parameters of the plant are adjusted without any numerical integration. After the adjustment, the adjusted estimators are transported to the control part and are used to control the input generation over an interval, which differs from the interval for estimation since computational time is necessary for estimator adjustment. We show analytically and numerically that the computational burden of the proposed system is less than the usual hybrid adaptive system and that the proposed adaptive control system is globally stable in spite of including ...

The design of an intelligent vibration absorber using numerical optimization techniques

The tuned absorber is an effective method of vibration reduction for systems that operate at constant frequency. However, the tuned absorber adds an additional low‐frequency resonance through which the system must pass during startup or shutdown conditions, thereby creating potentially excessive noise or vibration. An intelligent vibration absorber that will be effective during these periods has been designed. The mechanical system is modeled as a lumped mass, two‐degree‐of‐freedom system driven by a rotating unbalance that accelerates from rest to a constant driving frequency. The absorber has constant mass and damping but variable stiffness. The optimal value of absorber spring stiffness as a function of time was found using the optimization routine CONMIN. The time response was discretized and the optimization was performed on each successive time interval. The cost function and design variable used were the root‐mean‐squared displacement of the main mass and the absorber stiffness during each time interval. The process was repeated for several mass ratios, damping ratios, and accelerations. The intelligent absorber is shown to be superior to the tuned absorber for all cases.

Cell renewal in the gills of the fish Barbus conchonius

This radioautographic study established that the epithelial cells of the teleost gill have the cell division and cell migration patterns characteristic of a cell renewal system. [3H]Thymidine was injected into the small tropical fish Barbus conchonius, where it became incorporated into the newly synthesized DNA of dividing cells. Three fish were sacrificed at each of the following postinjection time intervals: 1, 12, 24, and 36 h. At 1 h, labeled nuclei were found only at the base of the gill filament, near the gill arch. At each successive time interval, labeled nuclei were found further out along the length of the gill filament. At later stages, labeled nuclei were also seen at the tips of the lamellae which project perpendicularly from the filaments. The number of labeled nuclei at the point of origin steadily declined with time. These data demonstrate that gill epithelial cells originate at the base of the gill arch and migrate both outward along the filament and upward along the lamellae. This pattern of cell division and cell migration demonstrates that the gill epithelium is a cell renewal system.

Effects of cast gold surface finishing on plaque retention

The relationship between the surface finish on cast gold restorations and the amount of plaque deposited on that surface was examined. Six different finishes were tested. The rouge finish was found to accumulate significantly less plaque than the other finishes. Every finish exhibited some plaque accumulation, even after the first 24 hours. Each finish accumulated progressively more plaque at each successive time interval.

スティックスリップ運動に伴うプレショックとプレスリップ及びそれ等に対する時間効果

Dynamic and static characteristics of stick-slip motion are studied experimentary for Horoman peridotite. Pressure system is similar to that of HOSKIN et al. Normal stress is constant (80bar) throughout all experiments. Stress rate is varied from 20bar/sec to 0.001bar/sec. Strain is measured at the side surface which is parallel to two pressure axes. Shocks accompanied by slips are detected by a piezoelectric transducer which is attached on a slip plane of central rock block. Overall dynamic range and frequency range of recording system is about 90dB and DC-10MHz respectively.Samples which have rough, middle rough and fine polished surface are prepared. Asperity height of fine polished surface is less than 10μm. The contact area is 9×9cm2.Characteristic features obtained in present study are as follows;A) In the case of fine polished surfaces.a) There are several modes of slip;1) Rapid speed partial area slip which emits small fore shock or preshock.2) Slow speed partial area slip which may be detected using strain gauges.3) Slow speed slip which extends over the contact area. This mode of slip may be divided into two submodes. One is followed by a rapid slip which extends over contact area. Therefor, this slow slip may be called a preslip. The other is not followed by a rapid slip.4) Rapid slip extended over contact surface which is called the main slip and emits a large shock which is called the main shock.b) There is a shock sequence for each main slip. This sequence of shocks contains several preshocks and a main shock. Preshocks can be observed 1-100msec prior to the main shock, and their amplitudes increase as exp((t-t0)n) where, at the main shock time, t=t0.c) Stress drop increases as successive main slips time interval ΔT increases. This relation may be expressed as A{1-exp(-C/(σc-σ)·ΔT)} where σc is the critical shear stress, σ is shear stress, A and C are some constants which may be varied with surface roughness or rock types.d) Shear stress is more effective than normal stress to increase stress drop.B) In the case of rough surfaces.a) There is only one mode of slip which corresponds to A)-a)-4).b) No preshocks can be observed.c) Stress drop increases as in the case of A), but constant C is smaller than the case of A).d) The effectiveness of shear stress to increase stress drop is same to the case of A).The feature of the fore-shock sequence of the earthquake Off Nemuro 1969 good fits to that of the preshock sequence A)-b). This shows that dynamic features of stic slip motion in the case of fine polished surface are more suitable than the case of rough surface to simulate earthquakes.There is a possibility to predict occurences of earthquakes in some case using the features of the preshock sequence and the preslip.

Statistical and probabilistic dependence between magnitude and time-interval for Mexico City earthquakes

This paper investigates the bivariate distribution of data consisting of earthquake magnitudes and the time-interval between earthquakes, to see whether the two variables are independent of each other. In searching for an association with magnitude, we consider time interval after an earthquake as well as the time interval before the earthquake. The characteristics of the interdependence between time interval ?t and earthquake magnitude M could be investigated using the statistical and probabilistic approaches. In the statistical approach the data for 250 successive earthquakes felt in Mexico City with magnitude 4.5 or greater, are used to compute the ? 2 -statistic to test the independence between the two variables. In the probabilistic approach we follow Suppes (1970) and as a measure of the probabilistic association we use an estimate of the earthquake conditional probabilities P (? t / M ) and P ( M /? T ) obtained through the application of bivariate distribution theory. The investigation revealed that there is some association between earthquake magnitude and the successive (after) time interval. There is no statistical evidence that the successive earthquake magnitude characteristics depend upon the preceding (before) time interval. However, from the probabilistic view point if the length of the preceding time interval increases, then, the probability of the occurrence of a successive large earthquake increases. DOI: 10.1111/j.2153-3490.1975.tb01707.x