CANADIAN STANDARD OF FREQUENCY

1959 ◽  
Vol 37 (1) ◽  
pp. 10-18 ◽  
Author(s):  
S. N. Kalra ◽  
C. F. Pattenson ◽  
M. M. Thomson
Keyword(s):  
High Precision ◽  
Phase Measurement ◽  
Frequency Standard ◽  
Frequency Stability ◽  
Absolute Frequency ◽  
Standard Frequency ◽  
Astronomical Observations ◽  
The Past ◽  
Time Signals ◽  
Very High

Over the past 3 years a frequency standard of very high precision has been installed in Canada. It is composed of equipment located in three different laboratories in Ottawa, Ontario, but separated by a few miles. Intercomparison of frequency between these laboratories, which is done by sending signals over telephone lines and related techniques, is briefly described. Results indicate frequency stability of about 2:1010 over short and long periods. Absolute frequency is determined from astronomical observations. International inter-comparison is carried out by phase measurement of standard frequency and by observations of time signals; some of the results are presented.

Design of parallel robots in microrobotics

Robotica ◽  
1997 ◽  
Vol 15 (4) ◽  
pp. 417-420 ◽  
Author(s):  
Eric Pernette ◽  
Simon Henein ◽  
Ivo Magnani ◽  
Reymond Clavel
Keyword(s):  
High Precision ◽  
Degrees Of Freedom ◽  
Design Guidelines ◽  
Parallel Robots ◽  
Precision Engineering ◽  
The Past ◽  
Elastic Joints ◽  
Increasing Demand ◽  
Very High

During the past few years, there has been an increasing demand in the field of precision engineering for fine motion in multi-degrees of freedom systems. These applications motivated the development of a new robotics field called microrobotics. In this paper, we review both the design guidelines for microrobots and the advantages of using parallel robots in very high precision applications. Parallel micromanipulators using elastic joints as well as structures manufactured in single solid and metallic bellows are introduced.

scholarly journals The dye quartz ring oscillator as a standard of frequency and time

1936 ◽  
Vol 155 (886) ◽  
pp. 498-519 ◽  
Keyword(s):  
High Precision ◽  
Frequency Standard ◽  
Logarithmic Decrement ◽  
Ring Oscillator ◽  
Quartz Resonators ◽  
Driving Circuit ◽  
Very High

At the time of his death the late Dr. D. W. Dye was investigating the oscillations of a quartz ring, cut to have a frequency of 20,000 cycles per second, and intended to form a frequency standard. The work has been continued, the properties of the ring fully investigated, and the oscillator has now been in operation as a standards of very high precision. Previous investigations on quartz resonators had shown conclusively the complexity of the modes of oscillation of thin quartz plates and even of plates of a thickness comparable with their length and breadth. Such complications in the vibrations increase the logarithmic decrement and render it necessary to increase the couple between the quartz and the driving circuit for the maintenance of oscillations. The frequency thereby becomes more dependent on circuit conditions and the ocsillator becomes less suitable as a standard of frequency. The type of oscillator described here and the method of mounting are chosen with a view to obtaining as pure a vibration and as low a decrement as possible.

scholarly journals Separate Universe calibration of the dependence of halo bias on cosmic web anisotropy

2020 ◽  
Vol 499 (3) ◽  
pp. 4418-4431 ◽  
Author(s):  
Sujatha Ramakrishnan ◽  
Aseem Paranjape
Keyword(s):  
Dark Matter ◽  
High Precision ◽  
Gaussian Distribution ◽  
Initial Perturbation ◽  
Analytical Framework ◽  
Web Environment ◽  
Wide Range ◽  
Galaxy Assembly ◽  
Very High ◽  
Good Agreement

ABSTRACT We use the Separate Universe technique to calibrate the dependence of linear and quadratic halo bias b1 and b2 on the local cosmic web environment of dark matter haloes. We do this by measuring the response of halo abundances at fixed mass and cosmic web tidal anisotropy α to an infinite wavelength initial perturbation. We augment our measurements with an analytical framework developed in earlier work that exploits the near-lognormal shape of the distribution of α and results in very high precision calibrations. We present convenient fitting functions for the dependence of b1 and b2 on α over a wide range of halo mass for redshifts 0 ≤ z ≤ 1. Our calibration of b2(α) is the first demonstration to date of the dependence of non-linear bias on the local web environment. Motivated by previous results that showed that α is the primary indicator of halo assembly bias for a number of halo properties beyond halo mass, we then extend our analytical framework to accommodate the dependence of b1 and b2 on any such secondary property that has, or can be monotonically transformed to have, a Gaussian distribution. We demonstrate this technique for the specific case of halo concentration, finding good agreement with previous results. Our calibrations will be useful for a variety of halo model analyses focusing on galaxy assembly bias, as well as analytical forecasts of the potential for using α as a segregating variable in multitracer analyses.

scholarly journals Equipartition principle for Wigner matrices

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhigang Bao ◽  
László Erdős ◽  
Kevin Schnelli
Keyword(s):  
High Precision ◽  
Quantum Systems ◽  
Wigner Matrices ◽  
Very High

Abstract We prove that the energy of any eigenvector of a sum of several independent large Wigner matrices is equally distributed among these matrices with very high precision. This shows a particularly strong microcanonical form of the equipartition principle for quantum systems whose components are modelled by Wigner matrices.

scholarly journals Truck Appointment System for Cooperation between the Transport Companies and the Terminal Operator at Container Terminals

2020 ◽  
Vol 11 (1) ◽  
pp. 168
Author(s):  
Hyeonu Im ◽  
Jiwon Yu ◽  
Chulung Lee
Keyword(s):  
Large Scale ◽  
Container Terminal ◽  
Container Terminals ◽  
The Past ◽  
Cooperation Model ◽  
Appointment System ◽  
New Form ◽  
Truck Appointment System ◽  
Import Container ◽  
Very High

Despite the number of sailings canceled in the past few months, as demand has increased, the utilization of ships has become very high, resulting in sudden peaks of activity at the import container terminals. Ship-to-ship operations and yard activity at the container terminals are at their peak and starting to affect land operations on truck arrivals and departures. In response, a Truck Appointment System (TAS) has been developed to mitigate truck congestion that occurs between the gate and the yard of the container terminal. The vehicle booking system is developed and operated in-house at large-scale container terminals, but efficiency is low due to frequent truck schedule changes by the transport companies (forwarders). In this paper, we propose a new form of TAS in which the transport companies and the terminal operator cooperate. Numerical experiments show that the efficiency of the cooperation model is better by comparing the case where the transport company (forwarder) and the terminal operator make their own decision and the case where they cooperate. The cooperation model shows higher efficiency as there are more competing transport companies (forwarders) and more segmented tasks a truck can reserve.

scholarly journals A pulsed-Laser Rb atomic frequency standard for GNSS applications

GPS Solutions ◽  
2021 ◽  
Vol 25 (3) ◽  
Author(s):  
S. Micalizio ◽  
F. Levi ◽  
C. E. Calosso ◽  
M. Gozzelino ◽  
A. Godone
Keyword(s):  
Optical Pumping ◽  
Frequency Standard ◽  
Frequency Stability ◽  
Allan Deviation ◽  
Rubidium Vapor ◽  
Vapor Cell ◽  
Continuous Regime ◽  
Remarkable Result ◽  
Averaging Time ◽  
Consequent Improvement

AbstractWe present the results of 10 years of research related to the development of a Rubidium vapor cell clock based on the principle of pulsed optical pumping (POP). Since in the pulsed approach, the clock operation phases take place at different times, this technique demonstrated to be very effective in curing several issues affecting traditional Rb clocks working in a continuous regime, like light shift, with a consequent improvement of the frequency stability performances. We describe two laboratory prototypes of POP clock, both developed at INRIM. The first one achieved the best results in terms of frequency stability: an Allan deviation of σy(τ) = 1.7 × 10−13 τ−1/2, being τ the averaging time, has been measured. In the prospect of a space application, we show preliminary results obtained with a second more recent prototype based on a loaded cavity-cell arrangement. This clock has a reduced size and exhibited an Allan deviation of σy(τ) = 6 × 10−13 τ−1/2, still a remarkable result for a vapor cell device. In parallel, an ongoing activity performed in collaboration with Leonardo S.p.A. and aimed at developing an engineered space prototype of the POP clock is finally mentioned. Possible issues related to space implementation are also briefly discussed. On the basis of the achieved results, the POP clock represents a promising technology for future GNSSs.

Septic Shock

1992 ◽  
Vol 7 (2) ◽  
pp. 90-100 ◽  
Author(s):  
Margaret M. Parker ◽  
Mitchell P. Fink
Keyword(s):  
Septic Shock ◽  
Supportive Care ◽  
Antimicrobial Therapy ◽  
Clinical Manifestations ◽  
Sepsis Syndrome ◽  
Adjunctive Treatment ◽  
Cardiovascular Changes ◽  
The Past ◽  
Sepsis And Septic Shock ◽  
Very High

The incidence of sepsis and septic shock has been increasing dramatically over the past 10 years. Despite advances in antimicrobial therapy, the mortality of septic shock remains very high. We review the clinical manifestations of sepsis and septic shock and describe the cardiovascular manifestations. Pathophysiology of the cardiovascular changes is discussed, and mediators believed to be involved in the pathogenesis are reviewed. Management of septic shock is also discussed, including antimicrobial therapy, supportive care, and adjunctive treatment aimed at affecting the mediators involved in producing the sepsis syndrome.

scholarly journals Q fever in South Australia: an outbreak in a meat-works

1962 ◽  
Vol 60 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Margaret D. Beech ◽  
A. E. Duxbury ◽  
Peter Warner
Keyword(s):  
Q Fever ◽  
South Australia ◽  
Meteorological Conditions ◽  
American Continent ◽  
North American Continent ◽  
The Past ◽  
The North ◽  
Epidemiological Features ◽  
Very High ◽  
Abattoir Workers

This paper consists of an epidemiological study of 52 cases of Q fever occurring in metropolitan Adelaide in 1957 and also a description of the results of a survey of 516 sera obtained from abattoir workers.The only case occurring outside the abattoirs was a dairy farmer who probably became infected while visiting the abattoirs. If this were so the incubation period (35 days) of his disease would have been exceptionally long.The general features of the outbreak, which lasted several months, differed from those on the North American continent in that the latter occurred explosively within a few days with very high attack rates. The situation in the Adelaide abattoirs is similar to that in Brisbane, where the disease appears to be endemic. However, unlike in Adelaide, cases are commonly recognized outside the abattoirs in Brisbane.In the abattoirs the disease affected mainly inspectors, those working on killing beef, and those working on offal. Mutton workers were not so severely affected. However, all these groups had similar incidences of low titre antibodies suggesting that in the past Q fever spread equally in all killing departments. In departments not directly associated with slaughtering the incidence both of cases in 1957 and low titre antibodies was relatively small.It was suggested that the epidemiological features of Q fever in Adelaide could be explained by the irregular appearance of animals from infected herds situated perhaps in Queensland—a known endemic area. Perhaps the appearance of such animals in the Adelaide abattoirs might be governed by meteorological conditions such that they were prevented from going to the ordinarily most convenient slaughterhouse.

scholarly journals The Economic Impact of Inflammatory Bowel Disease in Canada

2004 ◽  
Vol 18 (4) ◽  
pp. 255-257
Author(s):  
Robert Hilsden
Keyword(s):  
Inflammatory Bowel Disease ◽  
Bowel Disease ◽  
Labour Force ◽  
Incidence Rates ◽  
Age Group ◽  
Group Level ◽  
The Past ◽  
Inflammatory Bowel ◽  
Using Data ◽  
Very High

Longobardi and colleagues examined the effect of inflammatory bowel disease (IBD) on employment, using data from 10,891 respondents aged 20 to 64 years from the 1998 cycle of the Canadian National Population Health Survey (NPHS) (1). This sample included 187 (1.7%) subjects who self-reported IBD or a similar bowel disorder. A significantly greater proportion of IBD than non-IBD respondents reported that they were not in the labour force (28.9% versus 18.5%). Even after adjusting for other factors (age group, level of pain, etc), subjects with IBD had a 2.9% higher nonparticipation rate (21.4%). For example, among people not hospitalized within the past year and with no limitation of activities due to pain, IBD subjects were 1.2 times more likely to be unemployed than those without IBD. Subjects who reported high levels of pain had a very high probability of being out of the labour force. Based on Canadian annual compensation data for all employed persons in Canada, and age- and sex-specific prevalence, and incidence rates for IBD, the authors estimated that there are 119,980 IBD patients between the ages of 20 and 64 years in Canada and that this group includes 3479 people who are not in the labour force. This translates into lost wages of $104.2 million, or $868 per IBD patient

Formation flying for very high precision astrometry: NEAT and micro-NEAT mission concepts

2014 ◽  
Vol 2 (1) ◽  
pp. 3 ◽  
Author(s):  
Fabien Malbet ◽  
Alexis Brandeker ◽  
Alain Léger ◽  
Bjorn Jakobsson ◽  
Renaud Goullioud ◽  
...  
Keyword(s):  
High Precision ◽  
Formation Flying ◽  
Very High ◽  
Precision Astrometry
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