Forecasting Transaction Rates: The Autoregressive Conditional Duration Model

This paper will propose a new statistical model for the analysis of data that does not arrive in equal time intervals such as financial transactions data, telephone calls, or sales data on commodities that are tracked electronically. In contrast to fixed interval analysis, the model treats the time between observation arrivals as a stochastic time varying process and therefore is in the spirit of the models of time deformation initially proposed by Tauchen and Pitts (1983), Clark (1973) and more recently discussed by Stock (1988), Lamoureux and Lastrapes (1992), Muller et al. (1990) and Ghysels and Jasiak (1994) but does not require auxiliary data or assumptions on the causes of time flow. Strong evidence is provided for duration clustering beyond a deterministic component for the financial transactions data analyzed. We will show that a very simple version of the model can successfully account for the significant autocorrelations in the observed durations between trades of IBM stock on the consolidated market. A simple transformation of the duration data allows us to include volume in the model.

Naming the newly found landforms on Venus

The mapping of Venus is unique in the history of cartigraphy; never has so much territory been discovered and mapped in so short a period of time. Therefore, in the interest of international scientific communication, there is a unique urgency to the development of a system of names for surface features on Venus. The process began with the naming of features seen on radar images taken from Earth and continued through mapping expeditions of the U.S. and U.S.S.R. However, the Magellan Mission resolves features twenty-five times smaller than those mapped previously, and its radar data will cover an area nearly equivalent to that of the continents and the sea-floors of the Earth combined. The International Astronomical Union (IAU) was charged with the formal endorsement of names of features on the planets. Proposed names are collected, approved, and applied through the IAU Working Group for Planetary System Nomenclature (WGPSN) and its task groups, prior to IAU approval by the IAU General Assembly. Names approved by the WGPSN and its task groups, prior to final approval may be used on published maps and articles, provided that their provisional nature is stipulated. The IAU has established themes for the names to be used on each of the planets; names of historical and mythological women are used on Venus. Names of political entities and those identified with active religions are not acceptable, and a person must have been deceased for three years or more to be considered. Any interested person may propose a name for consideration by the IAU

Infinite charge mobility in muscovite at 300K

Evidence is presented for infinite charge mobility in natural crystals of muscovite mica at room temperature. Muscovite has a basic layered structure containing a flat monatomic sheet of potassium sandwiched between mirror silicate layers. It is an excellent electrical insulator. Studies of defects in muscovite crystals indicated that positive charge could propagate over great distances along atomic chains in the potassium sheets in absence of an applied electric potential. The charge moved in association with anharmonic lattice excitations that moved at about sonic speed and created by nuclear recoil of the radioactive isotope K40. This was verified by measuring currents passing through crystals when irradiated with energetic alpha particles at room temperature. The charge propagated more than 1000 times the range of the alpha particles of average energy and 250 times the range of channelling particles of maximum energy. The range is limited only by size of the crystal.Comment: 6 pages, 8 figure

Influence of moving breathers on vacancies migration

A vacancy defect is described by a Frenkel--Kontorova model with a discommensuration. This vacancy can migrate when interacts with a moving breather. We establish that the width of the interaction potential must be larger than a threshold value in order that the vacancy can move forward. This value is related to the existence of a breather centred at the particles adjacent to the vacancy.Comment: 11 pages, 10 figure

Doppler lidar observations of sensible heat flux and intercomparisons with a ground-based energy balance station and WRF model output

This is an open access article - Copyright @ 2009 E. Schweizerbart'sche VerlagsbuchhandlungDuring the Convective and Orographically induced Precipitation Study (COPS), a scanning Doppler lidar was deployed at Achern, Baden-Wüttemberg, Germany from 13th June to 16th August 2007. Vertical velocity profiles ('rays') through the boundary layer were measured every 3 seconds with vertical profiles of horizontal wind velocity being derived from performing azimuth scans every 30 minutes. During Intense Observation Periods radiosondes were launched from the site. In this paper, a case study of convective boundary layer development on 15th July 2007 is investigated. Estimates of eddy dissipation rate are made from the vertically pointing lidar data and used as one input to the velocity-temperature co-variance equation to estimate sensible heat flux. The sensible heat flux values calculated from Doppler lidar data are compared with a surface based energy balance station and output from the Weather Research and Forecasting (WRF) model.Funding is obtained from NER

Application of EREP imagery to fracture-related mine safety hazards and environmental problems in mining

The author has identified the following significant results. All Skylab 2 imagery received to date has been analyzed manually and data related to fracture analysis and mined land inventories has been summarized on map-overlays. A comparison of the relative utility of the Skylab image products for fracture detection, soil tone/vegetation contrast mapping, and mined land mapping has been completed. Numerous fracture traces were detected on both color and black and white transparencies. Unique fracture trace data which will contribute to the investigator's mining hazards analysis were noted on the EREP imagery; these data could not be detected on ERTS-1 imagery or high altitude aircraft color infrared photography. Stream segments controlled by fractures or joint systems could be identified in more detail than with ERTS-1 imagery of comparable scale. ERTS-1 mine hazards products will be modified to demonstrate the value of this additional data. Skylab images were used successfully to update a mined land map of Indiana made in 1972. Changes in mined area as small as two acres can be identified. As the Energy Crisis increases the demand for coal, such demonstrations of the application of Skylab data to coal resources will take on new importance

Fracture mapping and strip mine inventory in the Midwest by using ERTS-1 imagery

Analysis of the ERTS-1 imagery and high-altitude infrared photography indicates that useful fracture data can be obtained in Indiana and Illinois despite a glacial till cover. ERTS MSS bands 5 and 7 have proven most useful for fracture mapping in coal-bearing rocks in this region. Preliminary results suggest a reasonable correlation between image-detected fractures and mine roof-fall accidents. Information related to surface mined land, such as disturbed area, water bodies, and kind of reclamation, has been derived from the analysis of ERTS imagery

Hyperconductivity in fluorphlogopite at 300 K and 1.1 T

We report on studies of hyperconductivity in which electric charge moves in a solid in the absence of an applied electric field. This is indicative of a non-Ohmic mechanism. Our results are consistent with charge being carried ballistically by mobile nonlinear lattice excitations called quodons moving along close-packed atomic chains in the cation layers of some silicates. The finding that quodons can trap and carry a charge was first found by the authors in muscovite (Russell F. M. et al., EPL, 120 (2017) 46001), which previously was not possible. In this paper we have also found hyperconductivity in lepidolite, phlogopite and synthetic fluorphlogopite but not in biotite or quartz. We have found that a current continues to flow for many seconds after the creation of quodons is stopped, indicating they have long flight-paths. This shows that quodons are decoupled from phonons, must experience elastic reflection at boundaries and are not stopped by inevitable dislocations or other minor defects. We have also found that quodons can anneal defects caused by mechanical working of crystal faces. The current carried by quodons is unaffected by a magnetic field of 1.1 T.Ministerio de Ciencia e Innovación, PRX18/00360Ministerio de Economía y competitividad, FIS2015-65998- C2-2-PJunta de Andalucía, 2017/FQM-28

Ballistic charge transport by mobile nonlinear excitations

The developments in hyperconductivity, the loss-free transmission of electric charge at room temperature and above, due to the ballistic transport of electric charge in crystals with quasi-layered structure, are reported. The electric charge is carried by quodons, a type of mobile nonlinear intrinsic localized mode of lattice excitation observed as fossil tracks in layered silicates and recently by laboratory experiments. Here, ballistic means moving with minimal scattering or interaction with phonons. A test for hyperconductivity in solid materials is developed. It is based on the unique effect of short-term continuation of transport of charge, by total internal reflection, after creation of quodons has ceased. This effect is called the slow-quodon-decay effect or SQD effect. So far, only layered silicates have been shown to exhibit hyperconductivity. New evidence is presented for hyperconductivity in chrysotile, a nonlayered silicate material with new results. Being a fibrous material, it is more flexible than the sheet mica phyllosilicates. It is found that quodons can also be created and carry charge in very different materials, such as polymers, but without showing hyperconductivity, because of the very short range and lifetime of quodons in those materials.Ministerio de Ciencia, Innovación y Universidades PID2019-109175GB-C2