Expected Time Interval Research Articles

Socio-demographic predictors of the time interval between successive hospitalizations among patients with borderline personality disorder

Background: Borderline personality disorder (BPD) affects 0.7 to 2.7% of the adult population and higher rates are reported in inpatient care. Hospitalizations of BPD patients are a complex and controversial challenge for mental health professionals. Recurrent hospitalizations are common and it is essential to identify risk factors that characterize patients who benefit from their hospitalization and those who return to the ward shortly after discharge. Aim: To investigate the potential link between BPD patients’ socio-demographic factors and the expected time interval between their successive hospitalizations. Methods: A retrospective analysis of 1051 hospitalization records from 174 BPD patients. Through univariate, bivariate, and multivariate analyses, we investigated the possible relationship between patients’ primary socio-demographic factors and the time between their successive hospitalizations. Results: Patients’ age, marital status, and living arrangement were found to be statistically connected with the time interval between successive hospitalizations. Specifically, being older, married and/or patients to live with one’s spouse/partner seem to be linked with a longer time interval between successive hospitalizations compared to patients who are young, single/divorced and/or those who live with their parents. Conclusions: The expected time interval between successive hospitalization of BPD patients can be partly explained by their socio-demographic characteristics.

Short-lived product returns forecasting when customers are unwilling to return the product: A grey-graphical evaluation and review technique

Consumer electronics, such as mobile phones, laptops, and tablets, encounter the challenge of short product life cycles due to the rapid advancement of technology, marketing models, and rapidly changing consumer tastes. This study attempts to provide a forecasting model for a short-lived product for closed-loop supply chain planning. Importantly, we model the setting where the customers prefer to store the product instead of returning it for various reasons such as security and secondary use. We proposed a generic method that can be implemented for any technology-driven product's returns and remanufacturing process. We used the Graphical Evaluation and Review Technique to calculate the probability and quantity of product returns, the quantity of modules, parts, materials, and disposal. Then, we employed the Grey-Graphical Evaluation and Review Technique to calculate the expected time interval for core returns and the expected interval for the availability of module/parts/material for reconditioning/ remanufacturing of the product. An illustrative case study demonstrates the results of the forecasting model. Further, we analyzed the effect of customers' unwillingness to return the product on the reverse network. Our analysis asserts that the customer storing an end-of-use product has a greater impact on the probability of overall product return. Our analysis found that when customers tend to return the product instead of storing it for secondary use, the equivalence probability of returns can increase up to 91 %. In addition, we also address the effect of product return on the “ecological rucksack” of mobile phones. This can help policymakers design hassle-free return experiences and attractive customer incentives.

Reassessing contemporary labour curves

OBJECTIVES: Our purpose was to analyse the pattern of labor progression in Low risk parturients in contemporary obstetric practice. STUDY DESIGN: We extracted detailed labor data from 1531 low risk parturients with a term, singleton, vertex fetus of normal birth weight after spontaneous onset of labor. Cesarean deliveries,instrumental deliveries and those needed oxytocin augmentation were excluded.Those women whose new born needed resuscitation were also excluded. We used statistical measures to discover the average labor curve under contemporary practice. We also computed the expected time interval of the cervix to reach the next centimeter, the expected rate of cervical dilation at each phase of labor. RESULTS: Our average labor curve differs markedly from the Friedman curve . The cervix dilated substantially slower till 6 cm cervical dilatation. It took approximately 3.66 hours from 4 cm to 10 cm, compared with 2.5 hours under the Friedman curve. We observed no deceleration phase . Mean rate of cervical dilatation in active phase of labour was 1.42 cm/hr which is less than friedman’s rate of cervical dilatation which was 3 cm/hr. As per Zhang et al labour progress differentially at different degree of dilatation.

Growth Scale Prediction of Big Data for Information Systems Based on a Deep Learning SAEP Method

With the explosive growth of big data in various application areas, it is becoming very important for information management system to know the real-time growth change and the long-term increasing trend of big data. Thus, in this paper, we propose a big data growth scale prediction method based on deep learning intelligence. By analyzing the features of big data in various information systems, we summarize several basic data types which are ubiquitous in all kinds of information systems, and give the calculation method of each data growth scale time series. Considering the complex correlation among various types of data produced in information systems and the demand for data scale prediction, a deep learning prediction model, stacked autoencoders prediction (SAEP), is built. The previous time series prediction only considered one time series, but the SAEP can consider multiple time series simultaneously. We use data growth scale time series with different time interval as training sample sets to study features of big data in information systems, and then we can obtain the parameters of the SAEP model for the expected time interval. In order to solve the training problem of deep neural network, we also give a layer-wise training algorithm whose basic idea is to train all the hidden layers of the SAEP model layer by layer and then fine tune the parameters of the whole network. Repeated experiments show that the prediction performance of the SAEP model is stable and obviously better than the traditional exponential regression prediction method.

Configuration of inter-process communication with probabilistic model checking

Ever-increasing bit flip rates caused by shrinking hardware tiles increase the demand for resilient systems. In particular, safety- and functionality-critical system parts need to be protected. Inter-process communication is one such critical part. Applying fault tolerance techniques often comes with a configuration problem, since real-world systems typically have tunable system parameters. These need to be configured with respect to certain optimality criterion. The paper addresses the parameter synthesis problem for inter-process communication protocols that are affected by bit flips. Tunable parameters are the probability of error detection and the expected time interval between system refresh. We provide a tool that automatically generates a model of bit-flip-prone inter-process communication for a given set of processes and their communication structure. The tool is used to exemplarily generate a model of a space probe. Parametric extensions of probabilistic model checking are applied to obtain rational functions for the availability of the space probe and other characteristics. We find a configuration setting that maximizes availability and investigates side effects for this configuration. The paper also compares exemplarily for the space probe model the most-standard probabilistic model checking methods (value iteration, interval iteration, and exact model checking) with respect to their time consumption and accuracy and reveals complexity concerns arising when evaluating the rational functions.

Update on the Absolute Chronology of the Migration period in Central Europe (375–568 AD): new data from Maria ponsee, Lower Austria

ABSTRACTThe Danube region in Central Europe was one of the areas where several cultures appeared before moving further or being defeated during the Migration Period in the middle of the first millennium AD. The Lombards, who crossed the Danube in 505 AD, settled in the “Tullnerfeld” where the Maria Ponsee graveyard was excavated in 1965–1972. From the historical evidence about the temporal and spatial migration of the Lombards, it was concluded that the graveyard was in use between 505 and 568 AD by three groups of migrants. We processed and dated a new set of 23 bones, found in the Maria Ponsee site. The determined 14C dates fit well in the expected time interval, though discrimination between the grave groups could not be obtained. The dates were added to the chronological sequence, recording the Migration Period in Central Europe. The sequence lead to a good correlation of the modelled and historical data (Amodel = 87.6%). The results show differentiations of the respective tribes in the pre-Lombardic period. However, transitions between the Lombard phases were rather ambiguous, indicating that the Lombards set up new settlements while only partially abandoning the already inhabited ones before 546 AD.

Improved Physician Consult Response Times in an Academic Emergency Department After Implementation of an Institutional Guideline

BackgroundPhysician consultation in the Emergency Department (ED) can account for a significant portion of ED length of stay, which can lead to poor clinical outcomes. ObjectiveThe purpose of this study was to determine whether an institutional guideline could lead to a reduction in time between consult request and admission decision. This guideline codified a 90-min expected time interval to arrive and complete an admission disposition where the consulting and admitting service were the same in an academic ED with weekly audits and reports to departmental chairs and hospital administrators. MethodsThis was a study of consultation times of patients who presented to an academic ED 6 months before the adoption of an institutional guideline and 6 months after the adoption of the guideline. Data measurement in both periods included the length of time from ED consult order to admission disposition, time of ED discharge, number of ED consultations (single and multiple), ED admissions, and the hospital discharge time of admitted patients. ResultsPhysician consult response time decreased from 121 min to 100 min (p < 0.0001), and patients left the ED 18 min earlier (p = 0.0221) after implementation of the consultation guideline despite more ED visits, consultations, and admissions in the post-implementation time period. Patients were discharged from the inpatient setting 50 min later (p < 0.0001) after implementation of the guideline. ConclusionAn institutional guideline codifying timely ED consultations led to a significant reduction in the time from ED consultation to admission disposition while also allowing patients to leave the ED earlier in a high-occupancy academic medical center. However, the discharge time of admitted hospital patients was later after implementation of the guideline.

The consequences of using indirect signs that decay to determine species' occupancy

Statistical models of species' distributions rely on data on species' occupancy, or use, of sites across space and/or time. For rare or cryptic species, indirect signs, such as dung, may be the only realistic means of determining their occupancy status across broad spatial extents. However, the consequences of sign decay for errors in estimates of occupancy have not previously been considered. If signs decay very rapidly, then false-negative errors may occur because signs at an occupied site have decayed by the time it is surveyed. On the other hand, if signs decay very slowly, false-positive errors may occur because signs remain present at sites that are no longer occupied. We addressed this issue by quantifying, as functions of sign decay and accumulation rates: 1) the false-negative error rate due to sign decay and, 2) the expected time interval prior to a survey within which signs indicate the species was present; as this time interval increases, false-positives become more likely. We then applied this to the specific example of koala Phascolarctos cinereus occupancy derived from faecal pellet surveys using data on faecal pellet decay rates. We show that there is a clear trade-off between false-negative error rates and the potential for false-positive errors. For the koala case study, false-negative errors were low on average and the expected time interval prior to surveys that detected pellets indicate the species was present within less than 2-3 yr. However, these quantities showed quite substantial spatial variation that could lead to biased parameter estimates for distribution models based on faecal pellet surveys. This highlights the importance of observation errors arising from sign decay and we suggest some modifications to existing methods to deal with this issue.

Dim light melatonin onset in normal adults and its relationship with sleep timing and diurnal preference

Dim light melatonin onset (DLMO) is defined as the start of the melatonin production in the evening during dim light conditions and has become a reliable phase marker of the circadian clock. The aim of the study was to investigate DLMO and its association with sleep timing and diurnal preferences in healthy working adults during real-life conditions. Fourteen adults were investigated. A sleep diary was kept during the preceding week, but no fixed sleep–wake schedule was implemented. Diurnal preferences were measured with the Horne–Östberg Morningness–Eveningness Questionnaire. DLMO was defined as the time point when melatonin in saliva exceeded a threshold of 3 ng/L. Results showed that DLMO appeared in the expected time interval but was not significantly associated with sleep timing or diurnal preference. The results illustrate the complexity of monitoring sleep patterns in real-life settings.

Marginal Instability and Intermittency in Stochastic Systems—Part II: Systems With Rapid Random Variations in Parameters

Dynamic systems with lumped parameters, which experience random temporal variations, are considered. The variations “smear” the boundary between the system’s states, which are dynamically stable and unstable in the classical sense. The system’s response within such a “twilight zone” of marginal instability is found to be of an intermittent nature, with alternating periods of zero (or almost-zero) response and rare short outbreaks. As long as it may be impractical to preclude completely such outbreaks for a designed system, subject to highly uncertain dynamic loads, the corresponding system’s response should be analyzed. Results of such analyses are presented for cases of slow and rapid (broadband) parameter variations in Papers I and II, respectively. The former case has been studied in Paper I (2008, “Marginal Instability and Intermittency in Stochastic Systems—Part I: Systems With Slow Random Variations of Parameters,” ASME J. Appl. Mech., 75(4), pp. 041002) for a linear model of the system using a parabolic approximation for the variations in the vicinity of their peaks (so-called Slepian model) together with Krylov–Bogoliubov averaging for the transient response. This resulted in a solution for the probability density function (PDF) of the response, which was of an intermittent nature indeed due to the specific algorithm of its generation. In the present paper (Paper II), rapid broadband parameter variations are considered, which can be described by the theory of Markov processes. The system is assumed to operate beyond its stochastic instability threshold—although only slightly—and its nonlinear model is used accordingly. The analysis is based on the solution of the Fokker–Planck–Kolmogorov partial differential equation for the relevant stationary PDF of the response. Several such PDFs are analyzed; they are found to have integrable singularities at the origin, indicating an intermittent nature of the response. Asymptotic analysis is performed for the first-passage problem for such response processes with highly singular PDFs, resulting in explicit formulas for an expected time interval between outbreaks in the intermittent response.

An in vitro study of the effect of different occlusal registration materials on the reproducibility of mounting casts

This study compared the recorded interocclusal relationships produced using commonly used materials, determining which material accurately provides records of the interocclusal relationship for remounting. Ten occlusal registration materials were used in this study. Maxillary and mandibular casts were mounted on an articulator in maximum intercuspation. The interocclusal relationship was recorded with each specimen under a constant weight. Remounting of the mandibular cast was accomplished with the interocclusal record. The record was removed and the interocclusal contact recorded using occlusal indicator wax. The penetration of contacts was counted. This process was repeated using three specimens for each of the 10 materials used and measured. A standard deviation analysis was done on the number of penetration contacts. Stone interocclusal records were the most accurate material for occlusal registration. Wax wafer interocclusal records were the least accurate material. Clinical Application: This study suggests that the choice of material used for occlusal registration should be based on the expected time interval between occlusal registration and mounting of casts. If the mounting is expected immediately following the interocclusal registration, bite stone is the material of choice for occlusal registration. When a delay is expected between occlusal registration and mounting of the casts, non-eugenol zinc oxide may be chosen as the registration material.

Giant Cell Tumor of Tendon Sheath

Giant cell tumors of tendon sheath (GCTTS) are rare in children. We hypothesized that GCTTS in children probably behave in a similar manner to the adult lesions, with regard to clinical features, imaging characteristics, histology, and recurrence rates after surgical excision. We retrospectively reviewed 29 children diagnosed and treated for GCTTS during a 16-year period and evaluated the above characteristics to compare these results with published data for adult patients. A telephone questionnaire survey was also conducted to assess the current symptoms and function, satisfaction with procedure, and incidence of recurrence. In children, we noted similar predilection for lesions in both upper and lower extremities. Most cases, 28 (96%) of 29, presented with a gradual enlarging soft tissue mass. Plain radiography demonstrated soft tissue swelling in 50% of cases. Magnetic resonance imaging features were noted to be variable, although low signal intensity on T1- and T2-weighted images was noted in most lesions. Incisional biopsy with intraoperative frozen section and histological evaluation was the gold standard for accurate diagnosis. We noted no recurrence at final follow-up in any of our cases. Twenty-two (75%) of these 29 patients had follow-up of more than 2 years, with no recurrence, and the remaining 7 had follow-up between 1 to 2 years, which may seemingly be adequate from perspective of expected time interval for early recurrences. Meticulous dissection and excision with appropriate use of magnifying surgical loupes are likely factors that may help to minimize the recurrence rate.

Delayed Resolution of Chiari I-associated Hydromyelia after Posterior Fossa Decompression: Case Report and Review of the Literature

The expected time interval for resolution of hydromyelia after Chiari I decompression is lacking in the literature. This case report highlights one instance of delayed resolution of Chiari-induced hydromyelia. We report an adolescent girl with a Chiari I malformation and hydromyelia. A suboccipital craniectomy and C1 laminectomy with intradural exploration and duraplasty were performed. Serial imaging at 1 and 2 years after posterior cranial fossa decompression with duraplasty demonstrated no change in the size of the hydromyelia. At 3 years after surgery and before reoperation for continued hydromyelia, repeat magnetic resonance imaging demonstrated significant diminution of the fluid cavity. If this hydromyelia did resolve as a result of surgery, the interval for radiological observation clearly needs to be reconsidered. Unfortunately, this is an area in which the literature is lacking. With this case as a nidus, studies are now necessary to determine the range of time necessary for Chiari I malformation-related hydromyelia to resolve.

Reassessing the labor curve in nulliparous women

Objectives: Our purpose was to examine the pattern of labor progression in nulliparous parturients in contemporary obstetric practice. Study Design: We extracted detailed labor data from 1329 nulliparous parturients with a term, singleton, vertex fetus of normal birth weight after spontaneous onset of labor. Cesarean deliveries were excluded. We used a repeated-measures regression with a 10th-order polynomial function to discover the average labor curve under contemporary practice. With use of an interval-censored regression with a log normal distribution, we also computed the expected time interval of the cervix to reach the next centimeter, the expected rate of cervical dilation at each phase of labor, and the duration of labor for fetal descent at various stations. Results: Our average labor curve differs markedly from the Friedman curve. The cervix dilated substantially slower in the active phase. It took approximately 5.5 hours from 4 cm to 10 cm, compared with 2.5 hours under the Friedman curve. We observed no deceleration phase. Before 7 cm, no perceivable change in cervical dilation for more than 2 hour was not uncommon. The 5th percentiles of rate of cervical dilation were all below 1 cm per hour. The 95th percentile of time interval for fetal descent from station +1/3 to +2/3 was 3 hours at the second stage. Conclusion: Our results suggest that the pattern of labor progression in contemporary practice differs significantly from the Friedman curve. The diagnostic criteria for protraction and arrest disorders of labor may be too stringent in nulliparous women. (Am J Obstet Gynecol 2002;187:824-8.)

ENERGY BALANCE FOR RANDOM VIBRATIONS OF PIECEWISE-CONSERVATIVE SYSTEMS

Vibrations of systems with instantaneous or stepwise energy losses, e.g., due to impacts with imperfect rebounds, dry friction forces(s) (in which case the losses may be treated as instantaneous ones by appropriate introduction of the response energy) and/or active feedback “bang–bang” control of the systems' response are considered. Response of such (non-linear) systems to a white-noise random excitation is considered for the case where there are no other response energy losses. Thus, a simple linear energy growth with time between “jumps” is observed. Explicit expressions for the expected response energy are derived by direct application of the stochastic differential equations calculus, which contains the expected time interval between two consecutive jumps. The latter may be predicted as a solution to the relevant first-passage problem. Perturbational analysis of the relevant PDE for this problem for a certain vibroimpact system demonstrated the possibility for using the solution to the corresponding free vibration problem as a zero order approximation. The method is applied to an s.d.o.f. system with a feedback inertia control, designed according to a certain previously introduced “generalized reversed swings law”. Extensive Monte-Carlo simulation results are presented for this system as well as for several previously analyzed ones: system with impacts; system with dry friction; system with stiffness control; pendulum with controlled length. The results are compared with those due to the asymptotic stochastic averaging approach. Both methods are shown to provide adequate accuracy far beyond the expected applicability range of the asymptotic approach (which requires both excitation intensity and losses to be small), with direct energy balance being generally superior.

Eruption of the central incisor, the intermaxillary suture, and maxillary growth in patients with a single median maxillary central incisor

The occurrence of a single median maxillary central incisor (SMMCI) is a very rare condition and might be a sign of a more severe midline defect, which could be a mild degree of holoprosencephaly. Absence of the internasal and partial absence of the intermaxillary suture has been observed in a fetus with holoprosencephaly. The purpose of this study was to evaluate the intermaxillary suture, the eruption pattern of the single central incisor in the SMMCI condition, and the growth of the maxilla in a group of patients with SMMCI. A similar study was not found in the scientific literature. The material included orthopantomographs, dental radiographs, and lateral cephalometric radiographs from 11 patients with an SMMCI. The orthopantomographs and dental radiographs showed that the intermaxillary suture was abnormal anterior to the incisive foramen; however, the SMMCI erupted within the expected time interval. Superimposition on stable structures on lateral cephalometric radiographs from two untreated patients, in which growth analysis was possible, showed that the horizontal and vertical growth of the maxilla was normal. Due to the sutural midline defect it is suggested that a transversal growth analysis is included in all treatment planning of SMMCI patients.

Geomorphology and Geodynamics of the Cook-Austral Island-Seamount Chain in the South Pacific Ocean: Implications for Hotspots and Plumes

Among Pacific hotspot tracks, the Cook-Austral island-seamount chain is distinctly anomalous in geodynamic behavior, exhibiting repetitive episodes of volcanism at multiple sites, uplift of selected islands long after initial immersion by subsidence, and multiple alignments of volcanic edifices. Cook-Austral islands include a variety of disparate geomorphic types: volcanic islands without reefs, with fringing reefs, and with barrier reefs enclosing shallow lagoons, low-lying atolls; and makatea islands composed of volcanic cores surrounded by annular limestone tablelands. Neogene hotspot volcanism along the chain, built across Cretaceous-Paleogene seafloor, has occurred above three different mantle source regions, now located near its southeastern end, center, and northwestern end. Each hotspot has given rise to a separate age trend of volcanism along the same broad hotspot track, as the Pacific plate drifted over them, and each was initiated by eruption through the same region of lithosphere now located near the northwestern end of the compound chain. Age-distance trends of hotspot volcanism along the nearby Society and Marquesas chains depart less from expectation, but both the orientation and age trend of the Marquesas hotspot track also are anomalous. Lithospheric properties have seemingly influenced loci of South Pacific hotspot magmatism more than plume theory implies. Cook-Austral-Society-Marquesas volcanic suites are distinctly more alkalic than typical Hawaiian tholeiites, and display marked isotopic heterogeneities that reflect derivation from multiple mantle sources, even for individual volcanoes. As the volcanic assemblages all were erupted from the SOPITA-Superswell region of anomalously hot mantle including diverse recycled components, hotspots that built the several island chains may reflect bleeding of magma through lithospheric flaws from a buoyant subjacent pillow of atypical mantle, poised to melt readily from varied stimuli. Monotonic island subsidence is expected following cessation of hotspot volcanism, but episodes of post-immersion uplift have produced six makatea islands along the Cook-Austral chain. Makateas are tablelands of Neogene limestone, representing uplifted fringing reefs, and form annular girdles surrounding volcanic island cores. Despite limited erosional degradation, makatea surfaces provide a measure of net post-immersion island uplift. Paleoshoreline indicators of changing relative sea levels on Cook-Austral islands reflect the combined influence of seafloor thermotectonic subsidence, thermal rejuvenation associated with renewed hotspot activity, flexural bulges surrounding the isostatic loads of subsided volcanic edifices built out of sequence, the last-interglacial eustatic highstand in global sea level, and a mid-Holocene hydro-isostatic highstand in regional sea level. Key paleoshoreline indicators include emergent reef flats and microatolls recording former low-tide levels, paleobeachrock recording paleotidal range, and shoreline notches formed by solution and bioerosion at former high-tide levels. The elevations of paleonotches with respect to modern shoreline notches incised into the same seacliffs provide the most precise measures of shoreline emergence. Steady but slow thermotectonic subsidence is undetectable for mid-Holocene paleoshoreline features, but has measurably altered the elevations of last-interglacial features. In the Cook Islands, paleoshoreline features on Rarotonga and Aitutaki are compatible with theoretical expectations for thermotectonic subsidence since the last interglacial, and with a post-mid-Holocene drawdown in hydro-isostatic sea level intermediate between amounts calculated and observed regionally. Four makatea islands, apparently uplifted along the flexural bulge surrounding Rarotonga, display slightly greater post-mid-Holocene emergence, unexpected amounts of post-last-interglacial emergence, and net makatea uplifts similar but not identical to calculated inferences. Excess elevations of last-interglacial terraces on the makatea islands may conceivably reflect continued magmatic inflation of the Rarotonga volcanic edifice long after cessation of surface volcanism. In the Austral Islands, makatea uplift reflects either thermal rejuvenation of lithosphere by hotspot volcanism or concurrent passage of the islands over an asthenospheric bump, or both. As for the Cook makateas, post-last-interglacial emergence of Rurutu implies persistence of uplift beyond the expected time interval, whereas post-mid-Holocene emergence of Tubuai can be ascribed entirely, within inherent uncertainty limits, to hydro-isostasy alone. The distribution of subsided and uplifted islands along the Cook-Austral chain reflects multiple hotspot activity, probably related to multiple mantle diapirs of local character rather than to deepseated plumes. Rapid Pacific plate motion can generate elongate hotspot tracks from transient hotspot activity unrelated to columnar advective plumes.

The use of foreshocks in probabilistic prediction along the Japan and Kuril trenches

Abstract This article is intended to evaluate the probabilities of occurrence of mainshocks immediately after the occurrence of possible foreshocks and propose an optimal prediction algorithm based on possible foreshocks along the Japan and Kuril trenches and also to investigate the regional variation of foreshock activity in that region. Every earthquake or earthquake cluster defined specifically, except for small aftershocks, is treated as a possible foreshock. The parameters for defining possible foreshocks are magnitude (Mf), the size of square segment [D° (latitude) × D° (longitude)], time interval (Tf), and the number of earthquakes (Nf) having occurred in that space-time. However, Tf is fixed at 10 days in this study. The expected space of mainshocks to occur is defined as the segment where proposed foreshocks have occurred, and the expected time interval (Ta) is varied as a parameter. To estimate the probabilities of occurrence of mainshocks with magnitude ≧Mm0 after the occurrence of possible foreshocks, the following three indices, alarm rate (AR), truth rate (TR), and probability gain (PG) are adopted. The parameters of Nf, Mf, D, and Ta have a significant effect on evaluating the probabilities. The optimal values of parameters for possible foreshocks, which may provide us with a totally performed prediction algorithm, are estimated on the basis of the Precursor Information Criterion (PIC) by using the Japan Meteorological Agency (JMA) hypocenter catalog data from 1980 to 1993. The estimated values are Mf ≧ 5, Nf = 3, Ta = 5 days, and D = 0.5° for mainshocks with magnitude ≧6, which give a set of values of 13%, 25%, 617, and 75 to AR, TR, PG, and PIC, respectively; and Mf ≧ 4, Nf = 1, Ta = 1 day, and D = 0.25° for mainshocks with magnitude ≧5, which give values of 9%, 0.8%, 56, and 220 to the same indices as above. Moreover, it is found by using the data from 1926 to 1993 that there is a strong regional variation of foreshock activity; that is, four regions exhibit high activity of foreshocks, and the deeper the hypocenter of the mainshock, the smaller the percentage of mainshocks preceded by foreshocks.

Possibility of measuring shear waves in oblique-impact experiments with in-material piezoresistance gauges

We suggest the use of in-material piezoresistance gauges to record shear waves in oblique-impact experiments. The advantages of the proposed technique are discussed in detail and possible candidates for shear gauges are suggested. A preliminary oblique-impact experiment, with a manganin gauge embedded in an alumina target, is described. The gauge record shows the arrival of two waves with the expected time interval as calculated from the longitudinal and shear velocities for alumina.