457 research outputs found
EC-GSM-IoT Network Synchronization with Support for Large Frequency Offsets
EDGE-based EC-GSM-IoT is a promising candidate for the billion-device
cellular IoT (cIoT), providing similar coverage and battery life as NB-IoT. The
goal of 20 dB coverage extension compared to EDGE poses significant challenges
for the initial network synchronization, which has to be performed well below
the thermal noise floor, down to an SNR of -8.5 dB. We present a low-complexity
synchronization algorithm supporting up to 50 kHz initial frequency offset,
thus enabling the use of a low-cost +/-25 ppm oscillator. The proposed
algorithm does not only fulfill the 3GPP requirements, but surpasses them by 3
dB, enabling communication with an SNR of -11.5 dB or a maximum coupling loss
of up to 170.5 dB.Comment: Wireless Communications and Networking Conference (WCNC), 201
Keep it simple: ranking health states yields values similar to cardinal measurement approaches
Abstract
OBJECTIVES: To examine the relationship between ordinal and cardinal valuation of health states.
STUDY DESIGN AND SETTING: We analyzed rank, visual analog scale (VAS), and time trade-off (TTO) responses for 52 health states defined using the EQ-5D classification system developed by the EuroQol Group. We analyzed 179,431 responses from 11,483 subjects in eight countries: Slovenia, Argentina, Denmark, Japan, Netherlands, Spain, United Kingdom, and United States. We first compared responses across methods by frequency of ties and values below dead. Ordinal associations between methods were evaluated using Spearman's correlation and Kendall's tau. Next, we estimated numerical values from rank responses using country-specific conditional logit models. After anchoring predicted values on a common scale, we further investigated the cardinal relationships between rank, VAS, and TTO-based values using Pearson's rho and quadratic regression.
RESULTS: For each country, rank responses are less likely than TTO responses to be tied and to indicate that states are worse than dead. In all countries, rank responses show a strong linear correlation with both TTO (Pearson's rho=0.88-0.99) and VAS (rho=0.91-0.98) responses. However, rank-ba
Aging, Transition, and Estimating the Global Burden of Disease
The World Health Organization's Global Burden of Disease (GBD) reports are an important tool for global health policy makers, however the accuracy of estimates for countries undergoing an epidemiologic transition is unclear. We attempted to validate the life table model used to generate estimates for all-cause mortality in developing countries.Data were obtained for males and females from the Human Mortality Database for all countries with available data every ten years from 1900 to 2000. These provided inputs for the GBD life table model and served as comparison observed data. Above age sixty model estimates of survival for both sexes differed substantially from those observed. Prior to the year 1960 for males and 1930 for females, estimated survival tended to be greater than observed; following 1960 for both males and females estimated survival tended to be less than observed. Viewing observed and estimated survival separately, observed survival past sixty increased over the years considered. For males, the increase was from a mean (sd) probability of 0.22 (0.06) to 0.46 (0.1). For females, the increase was from 0.26 (0.06) to 0.65 (0.08). By contrast, estimated survival past sixty decreased over the same period. Among males, estimated survival probability declined from 0.54 (0.2) to 0.09 (0.06). Among females, the decline was from 0.36 (0.12) to 0.15 (0.08).These results show that the GBD mortality model did not accurately estimate survival at older ages as developed countries transitioned in the twentieth century and may be similarly flawed in developing countries now undergoing transition. Estimates of the size of older-age populations and their attributable disease burden should be reconsidered
Initial PET Performance Evaluation of a Preclinical Insert for PET/MRI with Digital SiPM Technology
Hyperion-IID is a positron emission tomography (PET) insert which allows
simultaneous operation in a clinical magnetic resonance imaging (MRI) scanner.
To read out the scintillation light of the employed LYSO crystal arrays with a
pitch of 1 mm pitch and 12 mm in height, digital silicon photomultipliers (DPC
3200-22, Philips Digital Photon Counting) (DPC) are used. The basic PET
performance in terms of energy resolution, coincidence resolution time (CRT)
and sensitivity as a function of operating parameters, such as the operating
temperature, the applied overvoltage, activity and configuration parameters of
the DPCs, were evaluated on system level. The measured energy resolution did
not show a large dependency on the selected parameters and is in the range of
12.4-12.9% for low activities and degrades to ~13.6% at activities of ~100 MBq.
The CRT strongly depends on the selected trigger scheme (trig) of the DPCs. We
measured approximately 260 ps, 440 ps, 540 ps and 1300 ps for trig 1-4,
respectively. The trues sensitivity for a NEMA NU 4 mouse-sized scatter phantom
with a 70-mm-long tube of activity was dependent on the operating parameters
and was determined to be 0.4-1.4% at low activities. The random fraction stayed
below 5% at activities up to 100 MBq and the scatter fraction was evaluated as
~6% for an energy window of 411-561 keV and ~16% for 250-625 keV. Furthermore,
we performed imaging experiments using a mouse-sized hot-rod phantom and a
large rabbit-sized phantom. In 2D slices of the reconstructed mouse-sized
hot-rod phantom ({\O} = 28 mm), the rods were distinguishable from each other
down to a rod size of 0.8 mm. There was no benefit of the better CRT of trig 1
over trig 3, where in the larger rabbit-sized phantom ({\O} = 114 mm), we could
show a clear improvement of image quality using the time-of-flight information.Comment: Final journal version including the supplemntal data. The images in
the supplement were compressed to meet the arXiv file size limi
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The Hepatitis C Cascade of Care: Identifying Priorities to Improve Clinical Outcomes
Background: As highly effective hepatitis C virus (HCV) therapies emerge, data are needed to inform the development of interventions to improve HCV treatment rates. We used simulation modeling to estimate the impact of loss to follow-up on HCV treatment outcomes and to identify intervention strategies likely to provide good value for the resources invested in them. Methods: We used a Monte Carlo state-transition model to simulate a hypothetical cohort of chronically HCV-infected individuals recently screened positive for serum HCV antibody. We simulated four hypothetical intervention strategies (linkage to care; treatment initiation; integrated case management; peer navigator) to improve HCV treatment rates, varying efficacies and costs, and identified strategies that would most likely result in the best value for the resources required for implementation. Main measures Sustained virologic responses (SVRs), life expectancy, quality-adjusted life expectancy (QALE), costs from health system and program implementation perspectives, and incremental cost-effectiveness ratios (ICERs). Results: We estimate that imperfect follow-up reduces the real-world effectiveness of HCV therapies by approximately 75%. In the base case, a modestly effective hypothetical peer navigator program maximized the number of SVRs and QALE, with an ICER compared to the next best intervention of 14.5 million per 10,000 newly diagnosed individuals. Conclusions: We estimate that imperfect follow-up during the HCV cascade of care greatly reduces the real-world effectiveness of HCV therapy. Our mathematical model shows that modestly effective interventions to improve follow-up would likely be cost-effective. Priority should be given to developing and evaluating interventions addressing multiple points along the cascade rather than options focusing solely on single points
Outlining the Hidden Curriculum: Perspectives on Successfully Navigating Scientific Conferences
Scientific conferences and meetings are valuable opportunities for researchers to network, communicate, and develop knowledge. For early career scientists, conferences can also be intimidating, confusing, and overwhelming, especially without having adequate preparation or experience. In this Perspective, we provide advice based on previous experiences navigating scientific meetings and conferences. These guidelines outline parts of the hidden curriculum around preparing for and attending meetings, navigating conference sessions, networking with other scientists, and participating in social activities while upholding a recommended code of conduct
Pentraxin-3 is a PI3K signaling target that promotes stem cell–like traits in basal-like breast cancers
Basal-like breast cancers (BLBCs) exhibit hyperactivation of the phosphoinositide 3-kinase (PI3K) signaling pathway because of the frequent mutational activation of the PIK3CA catalytic subunit and the genetic loss of its negative regulators PTEN (phosphatase and tensin homolog) and INPP4B (inositol polyphosphate-4-phosphatase type II). However, PI3K inhibitors have had limited clinical efficacy in BLBC management because of compensatory amplification of PI3K downstream signaling loops. Therefore, identification of critical PI3K mediators is paramount to the development of effective BLBC therapeutics. Using transcriptomic analysis of activated PIK3CA-expressing BLBC cells, we identified the gene encoding the humoral pattern recognition molecule pentraxin-3 (PTX3) as a critical target of oncogenic PI3K signaling. We found that PTX3 abundance is stimulated, in part, through AKT- and nuclear factor κB (NF-κB)-dependent pathways and that presence of PTX3 is necessary for PI3K-induced stem cell-like traits. We further showed that PTX3 expression is greater in tumor samples from patients with BLBC and that it is prognostic of poor patient survival. Our results thus reveal PTX3 as a newly identified PI3K-regulated biomarker and a potential therapeutic target in BLBC
The episodic random utility model unifies time trade-off and discrete choice approaches in health state valuation
ABSTRACT:
BACKGROUND: To present an episodic random utility model that unifies time trade-off and discrete choice approaches in health state valuation.
METHODS: First, we introduce two alternative random utility models (RUMs) for health preferences: the episodic RUM and the more common instant RUM. For the interpretation of time trade-off (TTO) responses, we show that the episodic model implies a coefficient estimator, and the instant model implies a mean slope estimator. Secondly, we demonstrate these estimators and the differences between the estimates for 42 health states using TTO responses from the seminal Measurement and Valuation in Health (MVH) study conducted in the United Kingdom. Mean slopes are estimates with and without Dolan's transformation of worse-than-death (WTD) responses. Finally, we demonstrate an exploded probit estimator, an extension of the coefficient estimator for discrete choice data that accommodates both TTO and rank responses.
RESULTS: By construction, mean slopes are less than or equal to coefficients, because slopes are fractions and, therefore, magnify downward errors in WTD responses. The Dolan transformation of WTD responses causes mean slopes to increase in similarity to coefficient estimates, yet they are not equivalent (i.e., absolute mean difference = 0.179). Unlike mean slopes, coefficient estimates demonstrate strong concordance with rank-based predictions (Lin's rho = 0.91). Combining TTO and rank responses under the exploded probit model improves the identification of health state values, decreasing the average width of confidence intervals from 0.057 to 0.041 compared to TTO only results.
CONCLUSION: The episodic RUM expands upon the theo
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