652 research outputs found
Could the Pioneer anomaly have a gravitational origin?
If the Pioneer anomaly has a gravitational origin, it would, according to the
equivalence principle, distort the motions of the planets in the Solar System.
Since no anomalous motion of the planets has been detected, it is generally
believed that the Pioneer anomaly can not originate from a gravitational source
in the Solar System. However, this conclusion becomes less obvious when
considering models that either imply modifications to gravity at long range or
gravitational sources localized to the outer Solar System, given the
uncertainty in the orbital parameters of the outer planets. Following the
general assumption that the Pioneer spacecraft move geodesically in a
spherically symmetric spacetime metric, we derive the metric disturbance that
is needed in order to account for the Pioneer anomaly. We then analyze the
residual effects on the astronomical observables of the three outer planets
that would arise from this metric disturbance, given an arbitrary metric theory
of gravity. Providing a method for comparing the computed residuals with actual
residuals, our results imply that the presence of a perturbation to the
gravitational field necessary to induce the Pioneer anomaly is in conflict with
available data for the planets Uranus and Pluto, but not for Neptune. We
therefore conclude that the motion of the Pioneer spacecraft must be
non-geodesic. Since our results are model independent within the class of
metric theories of gravity, they can be applied to rule out any model of the
Pioneer anomaly that implies that the Pioneer spacecraft move geodesically in a
perturbed spacetime metric, regardless of the origin of this metric
disturbance.Comment: 16 pages, 6 figures. Rev. 3: Major revision. Accepted for publication
in Phys. Rev. D. Rev. 4: Added two reference
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Everolimus Exposure as a Predictor of Toxicity in Renal Cell Cancer Patients in the Adjuvant Setting: Results of a Pharmacokinetic Analysis for SWOG S0931 (EVEREST), a Phase III Study (NCT01120249).
BackgroundS0931 is assessing recurrence-free survival in renal cell carcinoma (RCC) patients randomized to receive everolimus (EVE) versus placebo for one year following nephrectomy. Due to a higher than expected dropout rate, we assessed EVE trough levels in the adjuvant setting to evaluate the relationship between EVE exposure and probability of toxicity.MethodsPatients received 10 mg daily EVE for nine 6-week cycles. Pre-dose whole blood samples were collected pre-cycle 2 and pre-cycle 3 and analyzed for EVE. Patients with pre-cycle 2 and/or pre-cycle 3 EVE results were used in the analysis. Patients were segregated into quartiles (Q) based on EVE levels and logistic regression was used to model the most common adverse event outcomes using EVE trough as a predictor. Hazard and odds ratios were adjusted for age, BMI and performance status.ResultsA total of 467 patients were included in this analysis. Quartiles normalized to an EVE dose of 10 mg/day were < 9.0, 9.0-12.9, 12.9-22.8, and > 22.8 ng/mL, respectively. EVE trough levels increased with increasing age (p < 0.001). Furthermore, EVE trough levels were higher in men than women (19.4 versus 15.4 ng/mL, p = 0.01). Risk of grade 2 + triglycerides was increased in Q2 and Q3 vs Q1 (OR = 2.08; p = 0.02 and OR = 2.63; p = 0.002). Risk of grade 2 + rash was increased in Q2 and Q4 vs Q1 (OR = 2.99; p = 0.01 and OR = 2.90; p = 0.02). There was also an increased risk of any grade 3 + tox in Q2 vs Q1 (OR = 1.71; p = 0.05).ConclusionsWe identified significant gender and age-related differences in EVE trough levels in patients receiving adjuvant treatment for RCC. Furthermore, our analysis identified significant associations between EVE exposure and probability of toxicity
A signal detection analysis of contingency data
There are many psychological tasks that involve the pairing of binary variables. The various tasks used often address different questions and are motivated by different theoretical issues and traditions. Upon closer examination, however, the tasks are remarkably similar in structure. In the present paper, we examine two such tasks, the contingency judgment task and the signal detection task, and we apply a signal detection analysis to contingency judgment data. We suggest that the signal detection analysis provides a novel interpretation of a well-established but poorly understood phenomenon of contingency judgments-the outcome-density effect
Circulating microRNAs and treatment response in the Phase II SWOG S0925 study for patients with new metastatic hormone‐sensitive prostate cancer
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141181/1/pros23452.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141181/2/pros23452_am.pd
Monitoring of Collaborative Assembly Operations: An OEE Based Approach
International audienceIn this paper we present requirements and concept generation principles for performance monitoring of a collaborative assembly task. Life cycle aspects are considered and an Overall Equipment Efficiency (OEE) based monitoring scenario for a developed passive collaborative robot (COBOT) test system is presented. In this case main benefits of applying COBOT are expected to be: improved productivity, improved quality, reduced production cost and improved ergonomics. Since human and COBOT are working co-operatively human actions have also affects on process performance, i.e. OEE. However a human's and machines or a COBOT's efficiency are undistinguishable directly from OEE factors. It is possible to infer cause of lower efficiency from the variables from which OEE factors are calculated. One such variable is cycle time, which is used to define performance efficiency
Impact of body mass index and fat distribution on sex steroid levels in endometrial carcinoma: A retrospective study
Background Obesity is an important cause of multiple cancer types, amongst which endometrial cancer (EC). The relation between obesity and cancer is complicated and involves alterations in insulin metabolism, response to inflammation and alterations in estradiol metabolism. Visceral obesity is assumed to play the most important role in the first two mechanisms, but its role in estradiol metabolism is unclear. Therefore, this retrospective study explores the relationship of body mass index (BMI), visceral fat volume (VAV) and subcutaneous fat volume (SAV) and serum levels of sex steroids and lipids in patients with endometrial cancer. Methods Thirty-nine postmenopausal EC patients with available BMI, blood serum and Computed Tomography (CT) scans were included. Serum was analyzed for estradiol, dehydroepiandrosterone sulfate (DHEAS), androstenedione, testosterone, cholesterol, triglycerides and high (HDL), low (LDL) and non-high density (NHDL) lipoprotein. VAV and SAV were quantified on abdominal CT scan images. Findings were interpreted using pearson correlation coefficient and linear regression with commonality analysis. Results Serum estradiol is moderately correlated with BMI (r = 0.62) and VAV (r = 0.58) and strongly correlated with SAV (r = 0.74) (p < 0.001 for all). SAV contributes more to estradiol levels than VAV (10.3% for SAV, 1.4% for VAV, 35.9% for SAV and VAV, p = 0.01). Other sex steroids and lipids have weak and moderate correlations with VAV or SAV. Conclusions This study shows that serum estradiol is correlated with BMI and other fat-distribution measures in postmenopausal endometrial cancer patients. Subcutaneous fat tissue contributes more to the estradiol levels indicating that subcutaneous fat might be relevant in endometrial cancer carcinogenesis.publishedVersio
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