Thursday 26 April 2012

Walking with coffee: Why does it spill?

Phys. Rev. E 85, 046117
volume 85, issue 4, pages 046117
Published 26 April 2012
DOI: http://dx.doi.org/10.1103/PhysRevE.85.046117

H. C. Mayer and R. Krechetnikov

Department of Mechanical Engineering, University of California, Santa Barbara, California 93106, USA

Abstract

In our busy lives, almost all of us have to walk with a cup of coffee. While often we spill the drink, this familiar phenomenon has never been explored systematically. Here we report on the results of an experimental study of the conditions under which coffee spills for various walking speeds and initial liquid levels in the cup. These observations are analyzed from the dynamical systems and fluid mechanics viewpoints as well as with the help of a model developed here. Particularities of the common cup sizes, the coffee properties, and the biomechanics of walking proved to be responsible for the spilling phenomenon. The studied problem represents an example of the interplay between the complex motion of a cup, due to the biomechanics of a walking individual, and the low-viscosity-liquid dynamics in it.

http://journals.aps.org/pre/abstract/10.1103/PhysRevE.85.046117

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Friday 20 April 2012

Your Two Weeks of Fame and Your Grandmother's

arXiv: 1204.4346 [cs.DL]
April 20, 2012

James Cook, UC Berkeley
Atish Das Sarma, eBay Research Labs
Alex Fabrikant, Google Research
Andrew Tomkins, Google Research

Abstract

Did celebrity last longer in 1929, 1992 or 2009? We investigate the phenomenon of fame by mining a collection of news articles that spans the twentieth century, and also perform a side study on a collection of blog posts from the last 10 years. By analyzing mentions of personal names, we measure each person's time in the spotlight, using two simple metrics that evaluate, roughly, the duration of a single news story about a person, and the overall duration of public interest in a person. We watched the distribution evolve from 1895 to 2010, expecting to find significantly shortening fame durations, per the much popularly bemoaned shortening of society's attention spans and quickening of media's news cycles. Instead, we conclusively demonstrate that, through many decades of rapid technological and societal change, through the appearance of Twitter, communication satellites, and the Internet, fame durations did not decrease, neither for the typical case nor for the extremely famous, with the last statistically significant fame duration decreases coming in the early 20th century, perhaps from the spread of telegraphy and telephony. Furthermore, while median fame durations stayed persistently constant, for the most famous of the famous, as measured by either volume or duration of media attention, fame durations have actually trended gently upward since the 1940s, with statistically significant increases on 40-year timescales. Similar studies have been done with much shorter timescales specifically in the context of information spreading on Twitter and similar social networking sites. To the best of our knowledge, this is the first massive scale study of this nature that spans over a century of archived data, thereby allowing us to track changes across decades.

http://arxiv.org/abs/1204.4346

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Friday 13 April 2012

Dressed for Sex: Red as a Female Sexual Signal in Humans

PLoS One. 2012; 7(4): e34607
Published online Apr 13, 2012
doi:  10.1371/journal.pone.0034607

Andrew J. Elliot and Adam D. Pazda

Department of Clinical & Social Sciences in Psychology, University of Rochester, Rochester, New York, United States of America

Background

In many non-human primate species, a display of red by a female serves as a sexual signal to attract male conspecifics. Red is associated with sex and romance in humans, and women convey their sexual interest to men through a variety of verbal, postural, and behavioral means. In the present research, we investigate whether female red ornamentation in non-human primates has a human analog, whereby women use a behavioral display of red to signal their sexual interest to men.

Methodology/Principal Findings

Three studies tested the hypothesis that women use red clothing to communicate sexual interest to men in profile pictures on dating websites. In Study 1, women who imagined being interested in casual sex were more likely to display red (but not other colors) on their anticipated web profile picture. In Study 2, women who indicated interest in casual sex were more likely to prominently display red (but not other colors) on their actual web profile picture. In Study 3, women on a website dedicated to facilitating casual sexual relationships were more likely to prominently exhibit red (but not other colors) than women on a website dedicated to facilitating marital relationships.

Conclusions/Significance

These results establish a provocative parallel between women and non-human female primates in red signal coloration in the mating game. This research shows, for the first time, a functional use of color in women's sexual self-presentation, and highlights the need to extend research on color beyond physics, physiology, and preference to psychological functioning.

Acknowledgments

We extend our appreciation to members of the approach-avoidance motivation lab at the University of Rochester for their competent and conscientious work on these studies.

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0034607

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Wednesday 4 April 2012

Increased photon emission from the head while imagining light in the dark is correlated with changes in electroencephalographic power: Support for Bókkon's biophoton hypothesis

Neuroscience Letters
Volume 513, Issue 2, 4 April 2012, Pages 151–154
http://dx.doi.org/10.1016/j.neulet.2012.02.021

B.T. Dotta [a,c], K.S. Saroka [a,b], M.A. Persinger [a,b,c]

[a] Behavioural Neuroscience Program, Laurentian University, Sudbury, Ontario, Canada P3E 2C6
[b] Human Studies Program, Laurentian University, Sudbury, Ontario, Canada P3E 2C6
[c] Biomolecular Sciences Program, Laurentian University, Sudbury, Ontario, Canada P3E 2C6

Abstract

Bókkon's hypothesis that photons released from chemical processes within the brain produce biophysical pictures during visual imagery has been supported experimentally. In the present study measurements by a photomultiplier tube also demonstrated significant increases in ultraweak photon emissions (UPEs) or biophotons equivalent to about 5 × 10−11 W/m2 from the right sides of volunteer's heads when they imagined light in a very dark environment compared to when they did not. Simultaneous variations in regional quantitative electroencephalographic spectral power (μV2/Hz) and total energy in the range of ∼10−12 J from concurrent biophoton emissions were strongly correlated (r = 0.95). The calculated energy was equivalent to that associated with action potentials from about 107 cerebral cortical neurons. We suggest these results support Bókkon's hypothesis that specific visual imagery is strongly correlated with ultraweak photon emission coupled to brain activity.

Highlights

► Cerebral photon emission increases with imagery.
► EEG power time-coupled to cerebral photon emissions.
► Power densities of EEG and brain photons match.
► Thinking is coupled to cerebral light emission.
► Imagery photon density increase is ∼10–11 W/m2.

http://www.sciencedirect.com/science/article/pii/S030439401200208X

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Sunday 1 April 2012

Do Female Sex Fantasies Reflect Adaptations for Sperm Competition?

Annales Zoologici Fennici
Apr 2012 : Volume 49 Issue 1-2:93-102

Petri Nummi & Jani Pellikka

Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland

Researchers have suggested that female strategies for sexual selection in humans include the promotion of sperm competition. Sperm competition entails the simultaneous presence of fertile sperm from at least two males in the female's reproductive organ competing for the opportunity to fertilise the ovum. Certain behaviour patterns near ovulation may enable such competition. In this paper, we describe relative preferences for female sexual fantasy types and explore the idea that these preferences may help us understand the settings and mechanisms that promote sperm competition, and discourage interfemale competition. To expand this exploration, we also examine whether preferences vary with respect to the menstrual cycle. Our preliminary findings indicate notable preferences among females for multiple male-partner fantasies over multiple female-partner fantasies or fantasies that include multiple male and female partners. This suggests that females find multipartner settings as arousing as males do, but the psychological mechanism relating to settings that include the presence of same sex competitors may differ from that of males. We also discovered some indications that the female preference for promoting sperm competition and avoiding interfemale competition is the highest and strongest near ovulation.

http://www.bioone.org/doi/abs/10.5735/086.049.0109

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