2,937 research outputs found
On the invisibility and impact of Robert Hooke’s theory of gravitation
Robert Hooke\u2019s theory of gravitation is a promising case study for probing the fruitfulness of
Menachem Fisch\u2019s insistence on the centrality of trading zone mediators for rational change in the history of
science and mathematics. In 1679, Hooke proposed an innovative explanation of planetary motions to Newton\u2019s
attention. Until the correspondence with Hooke, Newton had embraced planetary models, whereby planets
move around the Sun because of the action of an ether filling the interplanetary space. Hooke\u2019s model, instead,
consisted in the idea that planets move in the void space under the influence of a gravitational attraction
directed toward the sun. There is no doubt that the correspondence with Hooke allowed Newton to conceive a
new explanation for planetary motions. This explanation was proposed by Hooke as a hypothesis that needed
mathematical development and experimental confirmation. Hooke formulated his new model in a mathematical
language which overlapped but not coincided with Newton\u2019s who developed Hooke\u2019s hypothetical model into
the theory of universal gravitation as published in the Mathematical Principles of Natural Philosophy (1687). The
nature of Hooke\u2019s contributions to mathematized natural philosophy, however, was contested during his own
lifetime and gave rise to negative evaluations until the last century. Hooke has been often contrasted to Newton
as a practitioner rather than as a \u201cscientist\u201d and unfavorably compared to the eminent Lucasian Professor.
Hooke\u2019s correspondence with Newton seems to me an example of the phenomenon, discussed by Fisch in his
philosophical works, of the invisibility in official historiography of \u201ctrading zone mediators,\u201d namely, of those
actors that play a role, crucial but not easily recognized, in promoting rational scientific framework change
Psychosocial Outcomes and Physical Activity Levels of Children Participating in the Fun and Fit for Life Program
The Fun and Fit for Life Program attempts to combat health disparities for low-income children, by providing the opportunity to engage in positive youth development and physical activity experiences. Program goals include creating a mastery motivational climate; teaching three key values (cooperation, participation, respect), and promoting enjoyable physical activity. PURPOSE: The purpose of this study was to evaluate program effectiveness by assessing perceived physical competence, personal and social responsibility, coach-created climate, and physical activity levels. METHODS: Children from local after school groups, such as the Boys and Girls Club, were recruited to participate in the Fun and Fit for Life Program (4-6 90-minute sessions), taught primarily by undergraduate physical education students. Participants age 8-13 years-old (n=60) completed a pre and post survey to assess psychosocial variables. A subset of the children (n=48, age 6-10 years-old) wore accelerometers throughout the duration of the camp, to measure activity levels. RESULTS: Paired t-tests showed that personal and social responsibility at the end of camp were significantly higher than before camp started (p\u3c.05). Perceived physical competence did not change from beginning to end of camp. Regression analyses showed that greater perceptions of a mastery climate predicted increases in personal responsibility, social responsibility, and perceived competence (p\u3c.05). In terms of activity level, children were engaged in physical activity for an average of 60% of each 90-minute session. CONCLUSION: Findings suggest that Fun and Fit for Life is having a positive impact on children from a low-income environment. Children improved in their personal and social responsibility and engaged in light, moderate, and vigorous physical activity
Integrating EEG and MEG signals to improve motor imagery classification in brain-computer interfaces
We propose a fusion approach that combines features from simultaneously
recorded electroencephalographic (EEG) and magnetoencephalographic (MEG)
signals to improve classification performances in motor imagery-based
brain-computer interfaces (BCIs). We applied our approach to a group of 15
healthy subjects and found a significant classification performance enhancement
as compared to standard single-modality approaches in the alpha and beta bands.
Taken together, our findings demonstrate the advantage of considering
multimodal approaches as complementary tools for improving the impact of
non-invasive BCIs
The Newton–Leibniz Calculus Controversy, 1708-1730
This article examines the controversy between Isaac Newton and Gottfried Wilhelm Leibniz concerning the priority in the invention of the calculus. The dispute began in 1708, when John Keill accused Leibniz of having plagiarized Newton\u2019s method of fluxions. It will be shown that the mathematicians participating in the controversy in the period between 1708 and 1730\u2014most notably Newton, Leibniz, Keill, and Johann Bernoulli\u2014held different conceptions of mathematical method. The dispute began in a political climate agitated by the Hanoverian succession and was intertwined with tensions dividing the Royal Court. It developed into a discussion of technical issues concerning the relation between mathematics and natural philosophy and the methods of the integral calculus
Conceptulism and contextualism in the recent historiography of Newton’s Principia
Recently the Principia has been the object of renewed interest among mathematicians and physicists. This technical interpretative work has remained somewhat detached from the busy and fruitful Newtonian industry run by historians of science. In this paper will advocate an approach to the study of the mathematical methods of Newton's Principia in which both conceptual and contextual aspects are taken into consideration
In Memoriam: Derek Thomas Whiteside (1932–2008)
Derek Whiteside died in 2008. This is an overview of his contributio to Newtonian scholarship
O-GlcNAcylation as marker of antioxidant effects of vitamin E-stabilized ultra high molecular weight polyethylene in human osteoblast
Characterization and cartography of some Mediterranean soft-bottom benthic communities (Ligurian Sea, Italy)
Soft-bottom benthic communities were studied along the Western coast of the Ligurian Sea with a new approach using both videocamera surveys and collected samples. The preliminary distribution of soft-bottoms and the definition of the limits and status of seagrass beds were carried out in September 1991, using an underwater vehicle provided with a videocamera and towed by a boat. Moreover, 90 benthic samples were collected at 5-40 m depth in order to characterize the macrobenthic soft-bottom communities. Six soft-bottom benthic assemblages and two sea grass biotopes (Cymodocea nodosa and Posidonia oceanica) were revealed by means of underwater images and multivariate analysis (TWINSPAN) on samples collected. The communities inhabiting the infralittoral sandy and coarse sediments corresponded to those previously described in the Mediterranean Sea, whereas a large complex transition between sandy and muddy communities was recognized on circalittoral soft-bottoms. Information obtained with this approach was used to draw a map of the investigated areas at 1:10,000 scale. The employment of the two techniques was cost effective for both time and research effort
The interplay of exercise, placebo and nocebo effects on experimental pain
Over the last few decades, placebo, and nocebo effects in general, have been investigated at rest. This proposed study explores whether they could work even when the experience of pain occurs during a movement. Exercise itself can have a hypoalgesic effect, suggesting that placebo- and exercise-induced hypoalgesia could foster pain reduction. In the present study, we investigated the interplay of exercise, placebo and nocebo effects on pain. To this aim, we developed a machine-controlled isotonic motor task to standardize the exercise across participants and used a well-validated model of placebo and nocebo manipulations with reinforced expectations via a conditioning procedure including visual cues paired with heat painful stimulations. Participants reported expectations and pain on a trial-by-trial basis. We found that the standardized isotonic exercise elicited a reduction of pain intensity. Moreover, both exercise and placebo induced comparable hypoalgesic effects. When the exercise was added, placebo and nocebo effects were influenced by expectations but were not affected by fatigue or sex differences. Exercise-, placebo- and nocebo-induced pain modulation are likely to work through distinct mechanisms and neurophysiological research is needed to fully exploit the implications for sport, rehabilitation and pain management
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