184 research outputs found

    Impact and extinction signatures in complete Cretaceous-Tertiary (K-T) boundary sections

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    The Zumaya, Caravaca and Agost sections in Spain, the El Kef section in Tunisia and the Negev (Nahal Avdat) sections in Israel are among the most continuous, expanded and complete K-T boundary sections. The distribution patterns of the planktic faunas were quantitatively analyzed in closely spaced samples across the K-T boundary in these sections, in conjuction with the geochemistry, stable isotopes, mineralogy and magnetostratigraphy. Three hundred foraminiferal specimens were randomly selected and determined. Reliable estimates for the foraminiferal productivity changes across the K-T boundary and for the 1 to 2 Ma interval preceding the K-T boundary were made from the numbers of individuals/gram of sediment corrected for the sedimentation rates (calculated from magnetic reversals and lithology). No gradual or stepwise extinction is seen below the K-T boundary nor any productivity decrease. Stable isotope analyses show a warming just after deposition of the ejecta layer, not cooling as predicted by nuclear winter scenarios, although the duration of such cooling may be too short to be observed even in these complete sections. Low REE values and cpx spherules with quench textures idential to quench-textures in diagenetically altered spherules, strongly indicate an oceanic site of (one of) the impactor(s)

    Pooling Time Series Based on Slightly Different Questions About the Same Topic Forty Years of Survey Research on Happiness and Life Satisfaction in The Netherlands

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    Survey research on subjective wellbeing in The Netherlands started in the early 1970s. The time series happiness and life satisfaction that have emerged since then are unfortunately based on slightly different survey items of which one part uses verbal response scales and another part uses numerical response scales. The diversity of the survey items and a number of other measurement issues, such as the effects of changes in survey mode, hamper comparison over time and make it difficult to establish whether life became any better over the last forty years. These problems can be tackled using the recently developed Reference Distribution Method with which responses to equivalent but not identical survey questions can be pooled to obtain long, consistent time series. We applied the Reference Distribution method to pool time series of happiness and life satisfaction. We conclude that in the past 40 years the Dutch have become slightly happier and satisfied with their lives

    Stability of boundaries between response options of response scales: Does 'very happy' remain equally happy over the years?

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    __Abstract__ The differences between response scales in number and wording of response options make it hard to compare data from survey research and to perform research syntheses. A recent method that we have developed to tackle this problem is rooted in the idea that the transition points on a bounded continuum, on which verbal response options from a primary scale transit from one point to another, for instance from ‘happy’ to ‘very happy’, remain unchanged over time. The idea behind this is that although people may change their perception of, for example, their own happiness intensity over time, they are assumed not to change the degree of appreciation they attribute to the terms used to label response options. This is an important assumption for research syntheses that requires that everything remains unchanged, except for the change of interest. It means that if our method is applied to measurements at distinct points in time, differences in estimates of the mean and standard deviation can be attributed solely to changes in the frequency distributions on the primary scale. In this paper we apply the method to happiness and show that it is reasonable to assume that the transition points between the response options are stable over time

    Head Trauma not Associated with Long Term Effects on Autonomic Function

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    International Journal of Exercise Science 14(3): 779-790, 2021. Contact-sports can elicit concussions, which impacts autonomic function, as well as elicit repetitive head trauma, where autonomic function has not yet been assessed. The purpose of this study was to determine if differences in autonomic function exist among three groups (CTRL: healthy non-contact-sport participant, RHT: repetitive head trauma contact-sport participant, CONC: previous concussion). Forty participants (16 men and 24 women), aged 18-37 (22 ± 3), participated in the study. Participants were grouped based on their sport and concussion history (CTRL, RHT, and CONC). Body composition was measured via air displacement plethysmography. Prior to testing, participants were outfitted with equipment to evaluate heart rate, blood pressure, and cerebral-artery blood flow velocity (CBFv). The participant performed against three stimuli: deep breathing, Valsalva maneuver, and a 70° head-up tilt test. Following autonomic function testing, a YMCA submaximal cycle test was performed. All group comparisons were analyzed using a one-way ANOVA and all data are presented as means ± standard deviation. The results of this study indicated that the groups did not differ in respiratory sinus arrhythmia (CTRL: 22 ± 6 bpm, RHT: 21 ± 8 bpm, CONC: 19 ± 7 bpm, p = 0.471), Valsalva ratio (CTRL: 2.19 ± 0.39, RHT: 2.09 ± 0.37, CONC: 2.00 ± 0.47, p = 0.519), CBFv (CTRL: 47.74 ± 25.28 cm/s, RHT: 40.99 ± 10.93 cm/s, CONC: 43.97 ± 17.55 cm/s, p = 0.657), or tilt time (CTRL: 806.09 ± 368.37 sec, RHT: 943.07 ± 339.54 sec, CONC: 978.40 ± 387.98 sec, p = 0.479). However, CONC (113.24 ± 11.64 mmHg) had a significantly higher mean systolic blood pressure during the tilt test than CTRL (102.66 ± 7.79 mmHg, p = 0.026), while RHT (107.9 ± 9.0 mmHg) was not significantly different than CTRL (p = 0.39) or CONC (p = 0.319). The results of this study are the first step in determining if long-lasting deficits to the autonomic nervous system occur following a diagnosis of concussion. However, concussions do not seem to have lasting effects on autonomic function. Overwhelmingly, dysautonomia is not present during chronic recovery from concussions or in individuals with RHT from contact-sports. In the future, sex should be considered as a variable

    Conversion of Verbal Response Scales: Robustness Across Demographic Categories

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    Happiness and life satisfaction have traditionally been measured using verbal response scales, however, these verbal scales have not kept up with the present trend to use numerical response scales. A switch from a verbal scale to a numerical scale, however, causes a severe problem for trend analyses, due to the incomparability of the old and new measurements. The Reference Distribution Method is a method that has been developed recently to deal with this comparison problem. In this method use is made of a reference distribution based on responses to a numerical scale which is used to decide at which point verbally labelled response options transit from one state to another, for example from ‘happy’ to ‘very happy’. Next, for each wave of the time series in which the verbal scale is used, a population mean is estimated for the beta distribution that fits best to these transition points and the responses in this wave. These estimates are on a level that is comparable to that of the mean of the reference distribution and are appropriate for use in an extended time series based on the responses measured using a verbal and a numerical scale. In this paper we address the question of whether the transition points derived for the general population can be used for demographic categories to produce reliable, extended time series to monitor differences in trends among these categories. We conclude that this is possible and that it is not necessary to derive transition points for each demographic category separately

    Measures of happiness: Which to choose?

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    Happiness is defined as the subjective enjoyment of one’s life as a whole, also called ‘life-satisfaction.’ Two components of happiness are distinguished; an affective component (how well one feels most of the time) and a cognitive component (the degree to which one perceived to get what one wants from life). In this chapter, I present an overview of valid measures of these concepts, drawing on the ‘Collection of Happiness Measures’ of the ‘World Database of Happiness’. To date (2016), this collection includes more than twothousand measures of happiness, mostly single direct questions. Links in this text lead to detail about these measures and the studies in this chapter, I describe the differences and discuss their strengths and weaknesse

    Phase II randomised discontinuation trial of brivanib in patients with advanced solid tumours

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    Background: Brivanib is a selective inhibitor of vascular endothelial growth factor and fibroblast growth factor (FGF) signalling. We performed a phase II randomised discontinuation trial of brivanib in 7 tumour types (soft-tissue sarcomas [STS], ovarian cancer, breast cancer, pancreatic cancer, non-small-cell lung cancer [NSCLC], gastric/esophageal cancer and transitional cell carcinoma [TCC]). Patients and methods: During a 12-week open-label lead-in period, patients received brivanib 800 mg daily and were evaluated for FGF2 status by immunohistochemistry. Patients with stable disease at week 12 were randomised to brivanib or placebo. A study steering committee evaluated week 12 response to determine if enrolment in a tumour type would continue. The primary objective was progression-free survival (PFS) for brivanib versus placebo in patients with FGF2-positive tumours. Results: A total of 595 patients were treated, and stable disease was observed at the week 12 randomisation point in all tumour types. Closure decisions were made for breast cancer, pancreatic cancer, NSCLC, gastric cancer and TCC. Criteria for expansion were met for STS and ovarian cancer. In 53 randomised patients with STS and FGF2-positive tumours, the median PFS was 2.8 months for brivanib and 1.4 months for placebo (hazard ratio [HR]: 0.58, p Z 0.08). For all randomised patients with sarcomas, the median PFS was 2.8 months (95% confidence interval [CI]: 1.4e4.0) for those treated with brivanib compared with 1.4 months (95% CI: 1.3e1.6) for placebo (HR Z 0.64, 95% CI: 0.38e1.07; p Z 0.09). In the 36 randomised patients with ovarian cancer and FGF2-positive tumours, the median PFS was 4.0 (95% CI: 2.6e4.2) months for brivanib and 2.0 months (95% CI: 1.2e2.7) for placebo (HR: 0.56, 95% CI: 0.26e1.22). For all randomised patients with ovarian cancer, the median PFS in those randomised to brivanib was 4.0 months (95% CI: 2.6e4.2) and was 2.0 months (95% CI: 1.2e2.7) in those randomised to placebo (HR Z 0.54, 95% CI: 0.25e1.17; p Z 0.11). Conclusion: Brivanib demonstrated activity in STS and ovarian cancer with an acceptable safety profile. FGF2 expression, as defined in the protocol, is not a predictive biomarker of the efficacy of brivanib

    Habits of Mind: Designing Courses for Student Success

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    Although content knowledge remains at the heart of college teaching and learning, forward-thinking instructors recognize that we must also provide 21st-century college students with transferable skills (sometimes called portable intellectual abilities) to prepare them for their futures (Vazquez, 2020; Ritchhart, 2015; Venezia & Jaeger, 2013; Hazard, 2012). To “grow their capacity as efficacious thinkers to navigate and thrive in the face of unprecedented change” (Costa et al., 2023), students must learn and improve important study skills and academic dispositions throughout their educational careers. If we do not focus on skills-building in college courses, students will not be prepared for the challenges that await them after they leave institutions of higher education. If students are not prepared for these postsecondary education challenges, then it is fair to say that college faculty have failed them
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