11,963 research outputs found
Periodic motor impairments in a case of 48-hour bipolar ultrarapid cycling before and under treatment with valproate
Motor impairments of psychiatric patients can be assessed with digital recordings of handwriting tasks. The investigation of patients with bipolar affective disorders differentiates intraindividual changes related to the patient's fluctuating affective states. An unmedicated 67-year-old male with 48-hour bipolar ultrarapid cycling was investigated during 8 consecutive days of ultrarapid cycling and 4 weeks later, after remission under treatment with valproate. The handwriting skills of the patient followed the same rhythmic changes of the psychopathology in the first part of the study and a steady pattern in the second phase, after remission. Therefore, it can be assumed that the handwriting skills reflect a state marker of the disease. Poorer handwriting skills on the manic days, as compared to the depressive ones, support the hypothesis of a low arousal in manic patients. Copyright (C) 2000 S. Karger AG, Basel
Kodaikanal Digitized White-light Data Archive (1921-2011): Analysis of various solar cycle features
Long-term sunspot observations are key to understand and predict the solar
activities and its effects on the space weather.Consistent observations which
are crucial for long-term variations studies,are generally not available due to
upgradation/modifications of observatories over the course of time. We present
the data for a period of 90 years acquired from persistent observation at the
Kodaikanal observatory in India. We use an advanced semi-automated algorithm to
detect the sunspots form each calibrated white-light image. Area, longitude and
latitude of each of the detected sunspots are derived. Implementation of a
semi-automated method is very necessary in such studies as it minimizes the
human bias in the detection procedure. Daily, monthly and yearly sunspot area
variations obtained from the Kodaikanal, compared well with the Greenwich
sunspot area data. We find an exponentially decaying distribution for the
individual sunspot area for each of the solar cycles. Analyzing the histograms
of the latitudinal distribution of the detected sunspots, we find Gaussian
distributions, in both the hemispheres, with the centers at 15
latitude. The height of the Gaussian distributions are different for the two
hemispheres for a particular cycle. Using our data, we show clear presence of
Waldmeier effect which correlates the rise time with the cycle amplitude. Using
the wavelet analysis, we explored different periodicities of different time
scales present in the sunspot area times series.Comment: Accepted for Publication in A&
Period-magnitude relations for M giants in Baade's Window NGC6522
A large and complete sample of stars with K < 9.75 in the NGC6522 Baade's
Window is examined using light curves from MACHO and IJK from DENIS. All 4 of
the sequences ABCD in the K vs logP diagram of the LMC are seen in the Bulge.
The Bulge sequences however show some differences from the Magellanic Clouds.
The sequences may be useful as distance indicators. A new diagram of the
frequency of late-type variables is presented. The catalogued SR variables of
the solar nbd are found to be a subset of the total of SRs, biased towards
large amplitude.Comment: 11 pages 11 fig
BZBJ1058+5628: a new quasi-periodic BL Lac
We present the historic photographic light curves of three little known
Blazars (two BL Lacs and one FSRQ), BZB J1058+5628, BZQ J1148+5254 and BZB
J1209+4119 spanning a time interval of about 50 years, mostly built using the
Asiago plate archive. All objects show evident long-term variability, over
which short-term variations are superposed. One source, BZB J1058+5628, showed
a marked quasi-periodic variability of 1 mag on time scale of about 6.3 years,
making it one of the few BL Lac objects with a quasi-periodic behavior.Comment: Accepted by The Astronomical Journal; 7 figures; 7 table
Dynamic Behavior of Spiral-Groove and Rayleigh-Step Self-Acting Face Seals
Tests were performed to determine the dynamic behavior and establish baseline dynamic data for five self-acting face seals employing Rayleigh-step lift-pads and inward pumping as well as outward-pumping spiral grooves for the lift-generating mechanism. The primary parameters measured in the tests were film thickness, seal seat axial motion, and seal frictional torque. The data show the dynamic response of the film thickness to the motion of the seal seat. The inward-pumping spiral-groove seals exhibited a high-amplitude film thickness vibratory mode with a frequency of four times the shaft speed. This mode was not observed in the other seals tested. The tests also revealed that high film thickness vibration amplitude produces considerably higher average film thickness than do low amplitude film thickness vibrations. The seals were tested at a constant face load of 73 N (16.4 lb) with ambient air at room temperature and atmospheric pressure as the fluid medium. The test speed range was from 7000 to 17000 rpm. Seal tangential speed range was 34.5 to 83.7 m/sec (113 to 274 ft/sec)
The Long Term Optical Variability of the BL Lac object S5 0716+714: Evidence for a Precessing Jet
We present the historic light curve of the BL Lac object S5 0716+714,
spanning the time interval from 1953 to 2003, built using Asiago archive plates
and our recent CCD observations, together with literature data. The source
shows an evident long term variability, over which well known short term
variations are superposed. In particular, in the period from 1961 to 1983 the
mean brightness of S5 0716+714 remained significantly fainter than that
observed after 1994. Assuming a constant variation rate of the mean magnitude
we can estimate a value of about 0.11 magnitude/year. The simultaneous
occurrence of decreasing ejection velocities of superluminal moving components
in the jet reported by Bach et al. (2005) suggests that both phenomena are
related to the change of the direction of the jet to the line of sight from
about 5 to 0.7 degrees for an approximately constant bulk Lorentz factor of
about 12. A simple explanation is that of a precessing relativistic jet, which
should presently be close to the smallest orientation angle. One can therefore
expect in the next ten years a decrease of the mean brightness of about 1
magnitude.Comment: to appear on The Astronomical Journal, 17 pages, 7 figures. Fig.2 is
given as a separated jpg fil
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