27,776 research outputs found
A Light Dilaton in Walking Gauge Theories
We analyze the existence of a dilaton in gauge theories with approximate
infrared conformal symmetry. To the extent that these theories are governed in
the infrared by an approximate fixed point (walking), the explicit breaking of
the conformal symmetry at these scales is vanishingly small. If confinement and
spontaneous chiral-symmetry breaking set in at some infrared scale, the
resultant breaking of the approximate conformal symmetry can lead to the
existence of a dilaton with mass parametrically small compared to the
confinement scale, and potentially observable at the LHC.Comment: 5 pages, references added, final version in PR
MIMO In Vivo
We present the performance of MIMO for in vivo environments, using ANSYS HFSS
and their complete human body model, to determine the maximum data rates that
can be achieved using an IEEE 802.11n system. Due to the lossy nature of the in
vivo medium, achieving high data rates with reliable performance will be a
challenge, especially since the in vivo antenna performance is strongly
affected by near field coupling to the lossy medium and the signals levels will
be limited by specified specific absorption rate (SAR) levels. We analyzed the
bit error rate (BER) of a MIMO system with one pair of antennas placed in vivo
and the second pair placed inside and outside the body at various distances
from the in vivo antennas. The results were compared to SISO simulations and
showed that by using MIMO in vivo, significant performance gain can be
achieved, and at least two times the data rate can be supported with SAR
limited transmit power levels, making it possible to achieve target data rates
in the 100 Mbps.Comment: WAMICON 201
Interactions of a String Inspired Graviton Field
We continue to explore the possibility that the graviton in two dimensions is
related to a quadratic differential that appears in the anomalous contribution
of the gravitational effective action for chiral fermions. A higher dimensional
analogue of this field might exist as well. We improve the defining action for
this diffeomorphism tensor field and establish a principle for how it interacts
with other fields and with point particles in any dimension. All interactions
are related to the action of the diffeomorphism group. We discuss possible
interpretations of this field.Comment: 12 pages, more readable, references adde
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Anticoagulation in patients with atrial fibrillation and heart failure: Insights from the NCDR PINNACLE-AF registry.
BackgroundIn non-valvular atrial fibrillation (NVAF) patients, congestive heart failure (CHF) confers an increased risk of stroke or systemic thromboembolism. This risk is present in both heart failure (HF) with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). It is unclear if clinicians account for both types of CHF in their NVAF anticoagulation practices. Accordingly, we characterized current outpatient anticoagulation trends in NVAF patients with HFpEF compared to patients with HFrEF.MethodsThe outpatient NCDR PINNACLE-AF registry was analyzed to identify patients with NVAF and CHF. The study population was subdivided into HFpEF (ie, LVEF ≥ 40%) and HFrEF (LVEF < 40%). Anticoagulation rates by CHF group were compared and stratified by CHA2 DS2 -VASc score.ResultsA total of 340 127 patients with NVAF and CHF were identified, of whom 248 136 (73.0%) were classified as HFpEF and 91 991 (27.0%) as HFrEF. Patients with HFpEF had higher mean CHA2 DS2 -VASc scores and were more likely to be female, older, and have hypertension (P < 0.001). Unadjusted anticoagulation rates were significantly lower in patients with HFpEF compared to those with HFrEF (60.6% vs 64.2%, respectively). Lower rates of anticoagulation in the HFpEF group persisted after risk adjustment (RR: 0.93 [95% CI: 0.91, 0.94]). Stratification by CHA2 DS2 -VASc score demonstrated that lower rates of anticoagulation in patients with HFpEF persisted until a score of ≥5.ConclusionsPatients with NVAF and HFpEF have significantly lower anticoagulation rates when compared to their HFrEF counterparts. These findings suggest a potential underappreciation of HFpEF as a risk factor in patients with NVAF
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