Search results for "Forecasting"
showing 10 items of 329 documents
Temporal weights in loudness: Investigation of the effects of background noise and sound level
2019
Previous research has consistently shown that for sounds varying in intensity over time, the beginning of the sound is of higher importance for the perception of loudness than later parts (primacy effect). However, in all previous studies, the target sounds were presented in quiet, and at a fixed average sound level. In the present study, temporal loudness weights for a time-varying narrowband noise were investigated in the presence of a continuous bandpass-filtered background noise and the average sound levels of the target stimuli were varied across a range of 60 dB. Pronounced primacy effects were observed in all conditions and there were no significant differences between the temporal w…
Developing cellular systems in vitro to simulate regeneration.
2014
In the past two decades, cellular systems in vitro have progressed from predominantly monocellular testing models to study the toxic effects of new biomaterials for replacement to relevant human coculture systems for regeneration, often a combination of progenitor cells with novel biomaterials. Considerable progress has been made in understanding cellular cross talk and its contribution to the vascularization of bone. Future challenges include using the established physiological, that is, nonactivated, stem cell niches as a platform to develop coculture models, which will enable the true in situ regenerative niche to be investigated. Hypoxia and a changing inflammatory status are factors th…
Anisometropia of spherical equivalent and astigmatism among myopes: a 23-year follow-up study of prevalence and changes from childhood to adulthood.
2017
Purpose To study anisometropia of spherical equivalent and astigmatism from the onset of myopia at school age to adulthood. Methods A total of 240 myopic schoolchildren (mean age 10.9 years), with no previous spectacles, were recruited during 1983–1984 to a randomized 3-year clinical trial of bifocal treatment of myopia. Examinations with subjective cyclopedic refraction were repeated 3 years later (follow-up 1) for 238 subjects and thereafter at the mean ages of 23.2 (follow-up 2) and 33.9 years (follow-up 3) for 178 and 134 subjects. After exclusions, the 102 subjects who attended all three follow-ups were included in the analyses. Corneal refractive power and astigmatism and anterior cha…
Clinical predictors of unstable coronary lesion morphology.
1995
We evaluated prospectively clinical and angiographic data in 400 patients, 200 with unstable and 200 with stable angina in order to determine which clinical markers could reliably predict unstable coronary artery lesions. Comparison of the angiogram of 200 patients with unstable and 200 with stable angina revealed a high-grade lesion (42% vs 23%, P < 0.0001), complex lesion morphology (49% vs 20%, P < 0.0001) and thrombus-containing lesions (7% vs 1%, P = 0.006) as typical findings in patients with unstable angina. A high-grade lesion and/or complex lesion (including thrombotic lesions but excluding total occlusion) was found in 61% of unstable and 34% of stable patients (P < 0.0001). Clini…
Popliteal Artery Aneurysm Repair in the Endovascular Era: Fourteen-Years Single Center Experience
2015
Abstract To compare outcomes of popliteal artery aneurysm (PAA) repair by endovascular treatment, great saphenous vein (GSV) bypass, and prosthetic bypass. Single center retrospective analysis of patients presenting PAA from 2000 to 2013. Patients were divided into endovascular treatment (group A); GSV bypass (group B); and prosthetic graft bypass (group C). Outcomes were technical success, perioperative mortality, and morbidity. Survival, primary and secondary patency, and freedom from reintervention rate were estimated. Differences in ankle-brachial index (ABI), in-hospital length of stay (InH-Los), red blood cell (RBC) transfusion, and limb loss were reported. Mean follow-up was 49 (medi…
Lipoprotein(a) and long-term recurrent infarction after an episode of ST-segment elevation acute myocardial infarction
2020
Background In established ischemic heart disease, the relationship between lipoprotein(a) and new cardiovascular events showed contradictory results. Our aim was to assess the relationship between lipoprotein(a) and very long-term recurrent myocardial infarction (MI) after an index episode of ST-segment elevation acute myocardial infarction (STEMI). Methods We included 435 consecutive STEMI patients discharged from October 2000 to June 2003 in a single teaching center. The relationship between lipoprotein(a) at discharge and recurrent MI was evaluated through negative binomial regression and Cox regression analysis. Results The mean age was 65 years (55-74 years), 25.5% were women, 34.7% we…
Diagnostic accuracy of computed tomographic colonography for the detection of advanced neoplasia in individuals at increased risk of colorectal cance…
2009
CONTEXT: Computed tomographic (CT) colonography has been recognized as an alternative for colorectal cancer (CRC) screening in average-risk individuals, but less information is available on its performance in individuals at increased risk of CRC. OBJECTIVE: To assess the accuracy of CT colonography in detecting advanced colorectal neoplasia in asymptomatic individuals at increased risk of CRC using unblinded colonoscopy as the reference standard. DESIGN, SETTING, AND PARTICIPANTS: This was a multicenter, cross-sectional study. Individuals at increased risk of CRC due to either family history of advanced neoplasia in first-degree relatives, personal history of colorectal adenomas, or positiv…
Fusion of technology management and financing management - Amazon's transformative endeavor by orchestrating techno-financing systems
2020
Amazon became the world R&D leader in 2017 by rapidly increasing R&D investment. Its R&D investment in 2017 was double that of 2015, 5 times that of 2012, and 10 times that of 2011. This rapid increase continued in 2018, and Amazon accomplished a skyrocketing increase in its market capitalization, closing to being the world's biggest company. Such a rapid increase in R&D and subsequent market value has raised questions about how to conduct R&D and secure a large amount of funds needed for high-risk investments. Amazon has provided hypothetical answers to both of these questions. Amazon has been conducting innovative R&D to transform routine or periodic alterations into significant improveme…
Sensitivity of external resources to cash flow under financial constraints
2014
Abstract This paper explores the external financing–cash flow relationship in capital structure theory by comparing unlisted (financially constrained) and listed (financially unconstrained) companies. We postulate that investment is determined endogenously in the case of unlisted firms, as they are strongly dependent on internally generated funds (cash flow). Consequently, unlisted firms invest their cash flow in profitable projects, using any residual cash flow to increase their holdings of safe assets. In turn, listed companies determine their investment exogenously and may reduce leverage if they raise an excess of cash flow. As a result, listed companies would react more negatively to s…
Improving demand forecasting accuracy using nonlinear programming software
2006
We address the problem of forecasting real time series with a proportion of zero values and a great variability among the nonzero values. In order to calculate forecasts for a time series, the model coefficients must be estimated. The appropriate choice of values for the smoothing parameters in exponential smoothing methods relies on the minimization of the fitting errors of historical data. We adapt the generalized Holt–Winters formulation so that it can consider the starting values of the local components of level, trend and seasonality as decision variables of the nonlinear programming problem associated with this forecasting procedure. A spreadsheet model is used to solve the problems o…