4,062 research outputs found
The roles of kinetic theory and gas-surface interactions in measurements of upper-atmospheric density
Kinetic theory and gas-surface interactions in measurements of upper atmospheric densit
A new method of determining the mean molecular mass
Method for determining mean molecular mass in upper atmospher
Generalized Interference Alignment --- Part I: Theoretical Framework
Interference alignment (IA) has attracted enormous research interest as it
achieves optimal capacity scaling with respect to signal to noise ratio on
interference networks. IA has also recently emerged as an effective tool in
engineering interference for secrecy protection on wireless wiretap networks.
However, despite the numerous works dedicated to IA, two of its fundamental
issues, i.e., feasibility conditions and transceiver design, are not completely
addressed in the literature. In this two part paper, a generalised interference
alignment (GIA) technique is proposed to enhance the IA's capability in secrecy
protection. A theoretical framework is established to analyze the two
fundamental issues of GIA in Part I and then the performance of GIA in
large-scale stochastic networks is characterized to illustrate how GIA benefits
secrecy protection in Part II. The theoretical framework for GIA adopts
methodologies from algebraic geometry, determines the necessary and sufficient
feasibility conditions of GIA, and generates a set of algorithms that can solve
the GIA problem. This framework sets up a foundation for the development and
implementation of GIA.Comment: Minor Revision at IEEE Transactions on Signal Processin
Human Factors Considerations in System Design
Human factors considerations in systems design was examined. Human factors in automated command and control, in the efficiency of the human computer interface and system effectiveness are outlined. The following topics are discussed: human factors aspects of control room design; design of interactive systems; human computer dialogue, interaction tasks and techniques; guidelines on ergonomic aspects of control rooms and highly automated environments; system engineering for control by humans; conceptual models of information processing; information display and interaction in real time environments
Impact of inter-correlated initial binary parameters on double black hole and neutron star mergers
The distributions of the initial main-sequence binary parameters are one of
the key ingredients in obtaining evolutionary predictions for compact binary
(BH-BH / BH-NS / NS-NS) merger rates. Until now, such calculations were done
under the assumption that initial binary parameter distributions were
independent. Here, we implement empirically derived inter-correlated
distributions of initial binary parameters primary mass (M1), mass ratio (q),
orbital period (P), and eccentricity (e). Unexpectedly, the introduction of
inter-correlated initial binary parameters leads to only a small decrease in
the predicted merger rates by a factor of 2 3 relative to the previously
used non-correlated initial distributions. The formation of compact object
mergers in the isolated classical binary evolution favors initial binaries with
stars of comparable masses (q = 0.5 1) at intermediate orbital periods (log
P (days) = 2 4). New distributions slightly shift the mass ratios towards
smaller values with respect to the previously used flat q distribution, which
is the dominant effect decreasing the rates. New orbital periods only
negligibly increase the number of progenitors. Additionally, we discuss the
uncertainty of merger rate predictions associated with possible variations of
the massive-star initial mass function (IMF). We argue that evolutionary
calculations should be normalized to a star formation rate (SFR) that is
obtained from the observed amount of UV light at wavelength 1500{\AA} (SFR
indicator). In this case, contrary to recent reports, the uncertainty of the
IMF does not affect the rates by more than a factor of 2. Any change to the IMF
slope for massive stars requires a change of SFR in a way that counteracts the
impact of IMF variations on the merger rates. In contrast, we suggest that the
uncertainty in cosmic SFR at low metallicity can be a significant factor at
play.Comment: accepted for publication in A&
Attorney’s Guide to Montana Conservation Easements
Conservation Easement
Functional and structural vascular biomarkers in women 1 year after a hypertensive disorder of pregnancy
OBJECTIVES: Women with a previous hypertensive disorder of pregnancy (HDP: gestational hypertension and preeclampsia) have increased long-term cardiovascular disease risk. Recent meta-analyses show adverse levels of non-invasive functional and structural cardiovascular risk markers such as pulse wave velocity (PWV), heart-rate adjusted augmentation index (AIx75), carotid intima-media thickness (CIMT), and reactive hyperemia index (RHI) after HDPs, and suggest using these for cardiovascular risk stratification. However, it is not known if a previous HDP predict levels of these markers beyond classical cardiovascular risk factors. Study design and main outcome measures. We assessed PWV, AIx75, CIMT, RHI, classical cardiovascular risk factors, and pregnancy characteristics in 221 women 1 year postpartum (controls: 95, previous HDP: 126). Uni- and multi- variate regression analysis were conducted to assess associations between previous HDP and PWV, AIx75, CIMT or RHI. We adjusted for classical cardiovascular risk factors and pregnancy characteristics. A p-level < 0.05 was considered statistically significant. RESULTS: PWV was associated with previous HDP on univariate analysis. This effect was confounded by blood pressure and not significant after adjustment. We found no significant associations between AIx75, RHI, CIMT, and a previous HDP, neither before nor after adjustments. CONCLUSIONS: Associations between a previous HDP and PWV, AIx75, CIMT, or RHI 1 year postpartum can largely be explained by adverse levels of classical cardiovascular risk markers in women with a previous HDP. Women with previous HDP should receive primary prevention of cardiovascular disease, but PWV, AIx75, CIMT or RHI are unlikely to aid in cardiovascular risk stratification 1 year postpartum
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