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Ambulatory Blood Pressure Monitoring in Clinical Practice: A Review
Abstract:
Ambulatory blood pressure monitoring offers the ability to collect blood pressure readings several times an hour across a 24-hour period. Ambulatory blood pressure monitoring facilitates the identification of white-coat hypertension, the phenomenon whereby certain individuals who are not taking antihypertensive medication show elevated blood pressure in a clinical setting but show nonelevated blood pressure averages when assessed by ambulatory blood pressure monitoring. In addition, readings can be segmented into time windows of particular interest, for example, mean daytime and nighttime values. During sleep, blood pressure typically decreases, or dips, such that mean sleep blood pressure is lower than mean awake blood pressure. A nondipping pattern and nocturnal hypertension are strongly associated with increased cardiovascular morbidity and mortality. Approximately 70% of individuals have blood pressure dips of ≥10% at night, whereas 30% have nondipping patterns, when blood pressure remains similar to daytime average or occasionally increases above daytime average. The various blood pressure categorizations afforded by ambulatory blood pressure monitoring are valuable for clinical management of high blood pressure because they increase the accuracy for diagnosis and the prediction of cardiovascular risk.
Keywords:
Ambulatory blood pressure monitoring; High blood pressure; Masked hypertension; Nocturnal blood pressure; White-coat hypertensio
High Temporal Resolution XMM Monitoring of PKS 2155-304
The bright, strongly variable BL Lac object PKS 2155-304 was observed by XMM
for two essentially uninterrupted periods of ~11 and 16 hr on 30-31 May 2000.
The strongest variations occurred in the highest energy bands. After scaling
for this effect, the three softest bands (0.1-1.7 keV) showed strong
correlation with no measurable lag to reliable limits of \tau \ls 0.3 hr.
However, the hardest band (~3 keV) was less well-correlated with the other
three, especially on short time scales, showing deviations of ~10-20% in ~1 hr
although, again, no significant interband lag was detected. This result and
examination of previous ASCA and BeppoSAX cross-correlation functions suggest
that previous claims of soft lags on time scales of 0.3-4 hr could well be an
artifact of periodic interruptions due to Earth-occultation every 1.6 hr.
Previous determinations of the magnetic field/bulk Lorentz factor were
therefore premature, as these data provide only a lower limit of B
\gamma^{1/3} \gs 2.5 G. The hardest band encompasses the spectral region above
the high-energy break; its enhanced variability could be indicating that the
break energy of the synchrotron spectrum, and therefore of the underlying
electron energy distribution, changes independently of the lower energies.Comment: 13 pages, 3 figures, accepted by Ap
First U-Pb Zircon Ages for Late Miocene Ashfall Konservat-Lagerstatte and Grove Lake Ashes from Eastern Great Plains, USA
First U-Pb zircon ages for late Miocene Ashfall Konservat-Lagersta¨tte and Grove Lake ashes from eastern Great Plains, USA
This paper documents the first U-Pb zircon ages for Ashfall Fossil Beds (Nebraska, USA), a
terrestrial Konservat-Lagersta¨ tte mass-death assemblage that is arguably the most diverse
of its type and age. The Ashfall tephra was correlated with ignimbrites from the Bruneau-Jarbidge
volcanic field (12.7–10.5 Ma) in southwest Idaho based on geochemical analysis. The
methods and geochemical data supporting the original age assessment of the ash bed,
however, were never published, and there has been a persistent misconception that dateable
heavy minerals (e.g., zircon) are absent. Notwithstanding, we recovered abundant zircons
from Ashfall Fossil Beds, and from an ash bed ~6 km to the southeast at Grove Lake,
Nebraska, and analyzed them through LA-ICP-MS. Our new zircon U-Pb age of 11.86 ±
0.13 Ma substantiates correlation of the Ashfall Fossil Beds deposit to tuffs originating from
the Bruneau-Jarbidge caldera (~12.7–10.5 Ma). Our U-Pb zircon age of 6.42 ± 0.06 Ma for
the Grove Lake ash bed coincides with supervolcanic activity in the Heise volcanic field
(6.6–4.3 Ma) in eastern Idaho. These new dates improve age constraints of strata comprising
the Ogallala Group and the important paleontological site. Moreover, we find that detrital
and airfall zircons are unevenly distributed in the stratified ash beds we describe herein and
presumably in similar deposits worldwide. Therefore, a higher-resolution sampling scheme
is necessary in such cases.EAR-102328
First U-Pb zircon ages for late Miocene Ashfall \u3ci\u3eKonservat-Lagerstatte\u3c/i\u3e and Grove Lake ashes from eastern Great Plains, USA
This paper documents the first U-Pb zircon ages for Ashfall Fossil Beds (Nebraska, USA), a terrestrial Konservat-Lagerstatte mass-death assemblage that is arguably the most diverse of its type and age. The Ashfall tephra was correlated with ignimbrites from the Bruneau-Jarbidge volcanic field (12.7–10.5 Ma) in southwest Idaho based on geochemical analysis. The methods and geochemical data supporting the original age assessment of the ash bed, however, were never published, and there has been a persistent misconception that dateable heavy minerals (e.g., zircon) are absent. Notwithstanding, we recovered abundant zircons from Ashfall Fossil Beds, and from an ash bed ~6 km to the southeast at Grove Lake, Nebraska, and analyzed them through LA-ICP-MS. Our new zircon U-Pb age of 11.86 ± 0.13 Ma substantiates correlation of the Ashfall Fossil Beds deposit to tuffs originating from the Bruneau-Jarbidge caldera (~12.7–10.5 Ma). Our U-Pb zircon age of 6.42 ± 0.06 Ma for the Grove Lake ash bed coincides with supervolcanic activity in the Heise volcanic field (6.6–4.3 Ma) in eastern Idaho. These new dates improve age constraints of strata comprising the Ogallala Group and the important paleontological site. Moreover, we find that detrital and airfall zircons are unevenly distributed in the stratified ash beds we describe herein and presumably in similar deposits worldwide. Therefore, a higher-resolution sampling scheme is necessary in such cases
X-ray Spectral Variability and Rapid Variability of the Soft X-ray Spectrum Seyfert 1 Galaxies Ark 564 and Ton S180
The bright, soft X-ray spectrum Seyfert 1 galaxies Ark 564 and Ton S180 were
monitored for 35 days and 12 days with ASCA and RXTE (and EUVE for Ton S180).
The short time scale (hours-days) variability patterns were very similar across
energy bands, with no evidence of lags between any of the energy bands studied.
The fractional variability amplitude was almost independent of energy band. It
is difficult to simultaneously explain soft Seyferts stronger variability,
softer spectra, and weaker energy-dependence of the variability relative to
hard Seyferts. The soft and hard band light curves diverged on the longest time
scales probed, consistent with the fluctuation power density spectra that
showed relatively greater power on long time scales in the softest bands. The
simplest explanation is that a relatively hard, rapidly-variable component
dominates the total X-ray spectrum and a slowly-variable soft excess is present
in the lowest energy channels of ASCA. Although it would be natural to identify
the latter with an accretion disk and the former with a corona surrounding it,
a standard thin disk could not get hot enough to radiate significantly in the
ASCA band, and the observed variability time scales are much too short. The
hard component may have a more complex shape than a pure power-law. The most
rapid factor of 2 flares and dips occurred within ~1000 sec in Ark 564 and a
bit more slowly in Ton S180. The speed of the luminosity changes rules out
viscous or thermal processes and limits the size of the individual emission
regions to <~15 Schwarzschild radii (and probably much less), that is, to
either the inner disk or small regions in a corona
Search for Yukawa Production of a Light Neutral Higgs Boson at LEP
Within a Two-Higgs-Doublet Model (2HDM) a search for a light Higgs boson in
the mass range of 4-12 GeV has been performed in the Yukawa process e+e- -> b
bbar A/h -> b bbar tau+tau-, using the data collected by the OPAL detector at
LEP between 1992 and 1995 in e+e- collisions at about 91 GeV centre-of-mass
energy. A likelihood selection is applied to separate background and signal.
The number of observed events is in good agreement with the expected
background. Within a CP-conserving 2HDM type II model the cross-section for
Yukawa production depends on xiAd = |tan beta| and xihd = |sin alpha/cos beta|
for the production of the CP-odd A and the CP-even h, respectively, where tan
beta is the ratio of the vacuum expectation values of the Higgs doublets and
alpha is the mixing angle between the neutral CP-even Higgs bosons. From our
data 95% C.L. upper limits are derived for xiAd within the range of 8.5 to 13.6
and for xihd between 8.2 to 13.7, depending on the mass of the Higgs boson,
assuming a branching fraction into tau+tau- of 100%. An interpretation of the
limits within a 2HDM type II model with Standard Model particle content is
given. These results impose constraints on several models that have been
proposed to explain the recent BNL measurement of the muon anomalous magnetic
moment.Comment: 24 pages, 9 figures, Submitted to Euro. Phys. J.
Search for the Standard Model Higgs Boson with the OPAL Detector at LEP
This paper summarises the search for the Standard Model Higgs boson in e+e-
collisions at centre-of-mass energies up to 209 GeV performed by the OPAL
Collaboration at LEP. The consistency of the data with the background
hypothesis and various Higgs boson mass hypotheses is examined. No indication
of a signal is found in the data and a lower bound of 112.7GeV/C^2 is obtained
on the mass of the Standard Model Higgs boson at the 95% CL.Comment: 51 pages, 21 figure
Measurement of the Hadronic Cross-Section for the Scattering of Two Virtual Photons at LEP
The interaction of virtual photons is investigated using the reaction e+e- ->
e+e- hadrons based on data taken by the OPAL experiment at e+e- centre-of-mass
energies sqrt(s_ee)=189-209 GeV, for W>5 GeV and at an average Q^2 of 17.9
GeV^2. The measured cross-sections are compared to predictions of the Quark
Parton Model (QPM), to the Leading Order QCD Monte Carlo model PHOJET to the
NLO prediction for the reaction e+e- -> e+e-qqbar, and to BFKL calculations.
PHOJET, NLO e+e- -> e+e-qqbar, and QPM describe the data reasonably well,
whereas the cross-section predicted by a Leading Order BFKL calculation is too
large.Comment: 30 pages, 10 figures, Submitted to Eur.Phys.J.
Measurement of triple gauge boson couplings from WW production at LEP energies up to 189 GeV
A measurement of triple gauge boson couplings is presented, based on W-pair
data recorded by the OPAL detector at LEP during 1998 at a centre-of-mass
energy of 189 GeV with an integrated luminosity of 183 pb^-1. After combining
with our previous measurements at centre-of-mass energies of 161-183 GeV we
obtain k_g=0.97 +0.20 -0.16, g_1^z=0.991 +0.060 -0.057 and lambda_g=-0.110
+0.058 -0.055, where the errors include both statistical and systematic
uncertainties and each coupling is determined by setting the other two
couplings to their SM values. These results are consistent with the Standard
Model expectations.Comment: 28 pages, 8 figures, submitted to Eur. Phys. J.
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