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"Webb, James R"
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دليل الوالدين في تربية الأطفال الموهوبين
كتاب دليـل الوالدين حيث تتوافر لدى أسر الأطفال الموهوبين مصادر قليلة ذات معلومات موثوقة عن التنشئة السليمة للأطفال الموهوبين لذا فإن مؤلفي الكتاب الأربعة ذوو الخبرة المهنية التي تمتد لعقود في التعامل مع الأطفال الموهوبين وعائلاتهم يقدمون دليلا عمليا في مجالات عدة مثل خصائص الأطفال الموهوبين والمثالية وعدم السعادة والأكتئاب والعلاقات بين الأقران والدافعية والتحصيل المنخفض والعثور على المساعدة المهنية المختصة والشدة والسعي للكمال والتوتر والتخطيط التربوي وهموم تربية الأبناء.
BOOK
Prospective and Multicenter Evaluation of Outcomes for Quality of Life and Activities of Daily Living for Balloon Kyphoplasty in the Treatment of Vertebral Compression Fractures: The EVOLVE Trial
Abstract
BACKGROUND
Osteoporotic and neoplastic vertebral compression fractures (VCF) are common and painful, threatening quality of life and increasing risk of morbidity and mortality. Balloon kyphoplasty is a percutaneous option for treating painful cancer- and osteoporosis-related VCFs, supported by 2 randomized trials demonstrating efficacy benefits of BKP over nonsurgical care.
OBJECTIVE
To investigate 12-mo disability, quality of life, and safety outcomes specifically in a Medicare-eligible population, representing characteristic patients seen in routine clinical practice.
METHODS
A total of 354 patients with painful VCFs were enrolled at 24 US sites with 350 undergoing kyphoplasty. Four coprimary endpoints—Numerical Rating Scale (NRS) back pain, Oswestry Disability Index (ODI), Short Form-36 Questionnaire Physical Component Summary (SF-36v2 PCS), EuroQol-5-Domain (EQ-5D)—were evaluated for statistically significant improvement 3 mo after kyphoplasty. Data were collected at baseline, 7 d, and 1, 3, 6, and 12 mo (www.clinicaltrials.gov registration NCT01871519).
RESULTS
At the 3-mo primary endpoint, NRS improved from 8.7 to 2.7 and ODI improved from 63.4 to 27.1; SF-36 PCS was 24.2 at baseline improving to 36.6, and EQ-5D improved from 0.383 to 0.746 (P < .001 for each). These outcomes were statistically significant at every follow-up time point. Five device-/procedure-related adverse events, intraoperative asymptomatic balloon rupture, rib pain, and aspiration pneumonia, and a new VCF 25 d postprocedure, and myocardial infarction 105 d postprocedure were reported and each resolved with proper treatment.
CONCLUSION
This large, prospective, clinical study demonstrates that kyphoplasty is a safe, effective, and durable procedure for treating patients with painful VCF due to osteoporosis or cancer.
Journal Article
The Structure of Micro-Variability in the WEBT BL Lacertae Observation
We present the results of an in-depth analysis of the Whole Earth Blazar Telescope (WEBT) micro-variability observations made during a campaign done in 2020 on the blazar BL Lacertae. The data consisted of 231 days of optical imaging and we separated the long-term light curve into individual single-night light curves, and then chose 41 nights that contained over 100 individual observations and also showed micro-variations well above the noise. Micro-variability is defined as excursions in the order of 0.01–0.1 magnitudes over timescales of hours or minutes either above or below a linear background sampled over the entire night. We then fit each individual micro-variability curve with model pulses from turbulent cells using the turbulent jet model.. We present the results of the pulse fitting analysis, which yields turbulent cell sizes, amplitudes and turbulent plasma characteristics.
Journal Article
30 Years of Multifrequency Quasar Variability: A Personal Journey
I outline the history of and progress in observing and understanding quasar multi-frequency and multi-messenger variability from the point of view of someone who has been working in the field for over 30 years. I will present some important references for the evolution from optical monitoring to multi-frequency cooperative programs that revealed the true multi-frequency/multi-timescale nature of variability in these objects. Quasar observations began with separate radio and optical monitoring programs; then the optical and radio observations w ere combined. This was followed by expanding the analyses to include far IR, UV, X-rays, and finally adding gamma rays. This progression yielded simultaneous multi-frequency spectra of these objects and light curves over 15 decades in frequency. The future is adding particle (neutrino) and gravitational waves to the picture. I also present long-term (50 years) optical light curves, and discuss optical variability at all timescales from minutes to tens of years in some selected objects for which we have reliable long-term monitoring observations.
Journal Article
The Nature of Micro-Variability in Blazars
We present the results of a long-term study designed to investigate the nature of micro-variability in blazars carried out primarily at the Southeastern Association for Research in Astronomy (SARA) observatories. We analyzed micro-variability data of fifteen OVV quasars and BL Lac sources collected from 1995 to 2021. The data set consists of single-band light curves interspersed with multi-color and micro-variability observations. This paper reports over 900 nights of CCD observations. We also incorporated observations from other observers as well as observations gleaned from the literature into our analysis. We employed differential photometry to measure magnitudes and then construct the long-term and micro-variability light curves. Our results indicate that there is no correlation between the presence of micro-variations and the brightness of the source. We present a viable theory to explain the intermittent micro-variability as pulses of radiation emitted by individual turbulent cells in the relativistic jet, which are stimulated by a passing shock wave. We present model fits and test results for various data sets, including WEBT light curves, Kepler light curves and a TESS light curve. Although the consensus in the community is that blazar jets must be turbulent, the identification of micro-variations as manifestations of actual turbulent cells is important for modeling these turbulent jets. We can obtain estimates of cell sizes (assuming a shock speed), and the distribution of cell sizes derived from observations is consistent with numerical simulation predictions.
Journal Article
Roles of sulfate adsorption and base cation supply in controlling the chemical response of streams of western Virginia to reduced acid deposition
Decreased acid deposition over recent decades has led to reductions in streamwater acidity on a widespread basis throughout the U.S. and Europe. A notable exception has been the southern Appalachian Mountains of the southeastern U.S., where declines in acid deposition have not translated into similar trends in stream chemistry in these watersheds with highly-weathered soils. To better characterize this observed behavior, streamwater samples collected at 64 sites in western Virginia on a quarterly basis from 1987 to 2011 were analyzed for chemical properties. Individual watershed response was strongly influenced by the dominant underlying bedrock, which affected sulfate $\\left({\\mathrm{S}\\mathrm{O}}_{4}^{2-}\\right)$ adsorption and base cation supply. Overall, pH increased at a majority of sites across all bedrock types. However, acid neutralizing capacity (ANC) decreased at most sites underlain by base-poor bedrock, suggesting the susceptibility to episodic acidification remains a serious threat to these streams. The declines in ANC were more closely related the depletion of base cations (Ca²⁺, Mg²⁺, K⁺, and Na⁺) rather than increased ${\\mathrm{S}\\mathrm{O}}_{4}^{2-}$ concentration. Sites with higher relative ${\\mathrm{S}\\mathrm{O}}_{4}^{2-}$ adsorption exhibited little change in ANC. A mass balance analysis of sulfur at a base-poor watershed revealed that exports have recently surpassed inputs for the first time within the several-decade period of record. This pattern appears likely to continue, and if sustained, the depletion of the stored pool of sulfur signifies an important precursor for further improvements in streamwater acidity in the region.
Journal Article
Coordinated Micro-Variability CIRCE Polarimetry and SARA JKT Multi-Frequency Photometry Observations of the Blazar S5 0716+71
A critical observation for testing the KRM jet model, in development at FIU, is to observe high time resolution, high accuracy photometry and polarimetry over a wide range of frequencies in the optically thin portion of the synchrotron spectrum. The detection of micro-variability during these observations would be ideal so the background and flaring components could be separated. Target of opportunity H-band photometry and polarimetry observations on the Gran Telescopio Canarias (GTC) 10.4-m with the Canarias InfraRed Camera Experiment (CIRCE) instrument were made in conjunction with the Southeastern Association for Research in Astronomy (SARA) JKT observing in the optical VRI bands in order to test the model. Here we present simultaneous micro-variability observations of Blazar S5 0716+71 made on 14 April 2017, with the CIRCE instrument on the GTC 10.4-m telescope and optical observations made with the 1.0-m SARA JKT in La Palma. The CIRCE observations consisted of high time resolution polarimetric observations in the H band over a period of 2.4 h on source, measuring both the H-band flux and the polarization degree and angle. Simultaneous observations with the SARA JKT 1.0-m yielded VRI light curves with about three minute time resolution over ∼4 h. 0716+71 showed only small amounts of variability during the observation. We present here the resulting data and a comparison to previous observations.
Journal Article
Multi-Frequency Blazar Micro-Variability as a Tool to Investigate Relativistic Jets
For the past 12 years we have been studying optical micro-variability of a sample of 15 Blazars. We summarize the results of this study and draw some basic conclusions about the characteristics of micro-variability. The intermittency, the stochastic nature, and the similar profile shapes seen in micro-variations at different times and in different objects have led us to a possible model to explain the observed micro-variations. The model is based on a strong shock propagating down a relativistic jet and encountering turbulence which causes density or magnetic field enhancements. We use the theory of Kirk, Reiger, and Mastichiadis (1998) to describe the pulse of synchrotron emission emanating from individual density enhancements energized by the shock. By fitting these “pulses” to micro-variability observations, we obtain excellent fits to actual micro-variations. The model predicts that the spectral index changes as a function of pulse duration. This effect should be observable in multi-frequency micro-variability data. We present the theoretical model, model fits of our micro-variability light curves, and preliminary multi-frequency micro-variability observations that support this model. A further test that has yet to be carried out involves observing polarization changes in different pulses.
Journal Article
Scrapping new product development efforts: when to keep going, when to fold
Purpose
The innovative process of new product development remains unique within most organizations. This uniqueness stems from the requirements of the new product development manager to grapple with both the universe of emerging technologies from which a new feature or improvement must be found and to simultaneously maintain a constant awareness of the requirements of an ever-changing customer base. Amongst all of this uncertainty, there is still a time when new product development managers choose to ignore the warning signals that a project is failing and continue to commit resources. This paper refers to this as irrational commitment. This paper aims to examine the uncertainty of new product development and the reasons for this irrational commitment to failed projects.
Design/methodology/approach
The paper used a structured systematic review of literature to identify the most common types of irrational commitment in new product development and their impact on the corporation.
Findings
The paper provides insights into the causes and effects of management irrationally committing to new product development projects that are doomed to failure. It suggests that the three major areas of knowledge that need to be better integrated into the decision-making process are technology trends, marketing knowledge and the capabilities of the company itself.
Research limitations/implications
Because of the chosen research approach of using a systematic review of literature, primary research needs to be conducted in the future to validate and refine the findings of the paper.
Practical implications
The paper provides leadership with guidelines to avoid irrationally committing to failed new product development efforts.
Originality/value
This paper adds to the literature on innovation systems.
Journal Article
Idiosyncratic Risk and REIT Returns
The volatility of a stock returns can be decomposed into market and firm-specific volatility, with the former commonly known as systematic risk and the later as idiosyncratic risk. This study examines the relevance of idiosyncratic risk in explaining the monthly cross-sectional returns of REIT stocks. Contrary to the CAPM theory, a significant positive relationship is found between idiosyncratic volatility and the cross-sectional returns. This suggests that firm-specific risk matters in REIT pricing. The regression results further show that once idiosyncratic risk is controlled for in the asset-pricing model, the size and book-to-market equity ratio factors ceased to be significant. The explanatory power of the momentum effect remains robust in the presence of idiosyncratic risk.
Journal Article