Predator or prey? The eyes have it

Crocodiles and gazelles don’t really see eye-to-eye on a number of issues—the culinary virtues of gazelle meat being the most prominent. But these animals do see the world differently, in part because of their pupils. The crocodile’s has a vertical slit, whereas the pupil of the gazelle is horizontal. The lion, lurking nearby, has a circular dot similar to humans. So why the different shapes? Researchers propose today in Science Advances that an animal’s status as predator or prey may be the determining factor. After analyzing the pupils of more than 200 land species including canines, felines, reptiles, and ungulates, the scientists found that short ambush predators such as alligators and foxes are more likely to have vertical pupils, whereas prey species—like gazelles or sheep—are more likely to have horizontal pupils. A vertical view is best for gauging distances along the ground, a useful ability when you’re lurking in the shadows and have only one shot at a mouse. A horizontal shape gives prey animals a panoramic view suited to spotting predators approaching from nearly any angle. This ability is enhanced by a feature that lets grazers rotate their eyes to keep their pupils parallel with the horizon. Circular pupils are generally found on animals that chase down their prey, such as cheetahs, or on taller ambush predators like lions and tigers. This suggests that above a certain shoulder height—about 42 cm—the functional advantages of vertical pupils are lost. The will to survive, it seems, has helped the eye of the tiger—and the fox and the horse—evolve pupils best suited to helping them do just that.
Source:http://news.sciencemag.org/biology/2015/08/video-predator-or-prey-eyes-have-it

Research Seminars in Mathematical Finance: Stochastic Volatility Models, Option Pricing, Calibration

Authors
Lorella Fatone, Dipartimento di Matematica e Fisica, Università di Camerino, Camerino, Italy.
Francesca Mariani, Dipartimento di Scienze Economiche, Università di Verona, Verona, Italy.
Maria Cristina Recchioni, Dipartimento di Management, Università Politecnica delle Marche, Ancona, Italy.
Francesco Zirilli, Dipartimento di Matematica "G. Castelnuovo", Università di Roma "La Sapienza", Roma, Italy.
Description

This ebook contains a set of slides that can be used to present lectures in a graduate course or in a research seminar in mathematical finance.

The ebook is divided in three chapter, each chapter is divided in three sections, each section contains a set of slides that can be used to present a lecture. The lectures are independent one from the others.

The lectures discuss the results of the research in mathematical finance of the authors during the years 2007-2012. The results presented are concerned with the study of stochastic volatility models (Heston, SABR models and their generalizations), and in particular with the option pricing and calibration problems relative to these models.These results have been published in papers appeared in academic journals. The papers are complemented with multimedia material and mathematical software available on the web.

If you want, you can read this book in SciencePG, Book with open access!

Scientists identify that memories can be lost and found

Summary:
A team of scientists believe they have shown that memories are more robust than we thought and have identified the process in the brain, which could help rescue lost memories or bury bad memories, and pave the way for new drugs and treatment for people with memory problems.

A team of scientists believe they have shown that memories are more robust than we thought and have identified the process in the brain, which could help rescue lost memories or bury bad memories, and pave the way for new drugs and treatment for people with memory problems.

Published in the journal Nature Communications a team of scientists from Cardiff University found that reminders could reverse the amnesia caused by methods previously thought to produce total memory loss in rats.

"Previous research in this area found that when you recall a memory it is sensitive to interference to other information and in some cases is completely wiped out.

"Our research challenges this view and we believe proves this not the case," according to Dr Kerrie Thomas, who led the research.

"Our research found that despite using a technique in the brain thought to produce total amnesia we've been able to show that with strong reminders, these memories can be recovered,"

Whilst the results were found in rats, the team hope it can be translated into humans and new drugs and treatments could be developed for people suffering with memory disorders.

Dr Thomas added: "We are still a very long way off from helping people with memory problems.

"However, these animal models do accurately reflect what's happening in humans and suggest that our autobiographical memories, our self-histories, are clouded by new memories rather than actually lost. This is an exciting prospect in terms of treating psychiatric illness associated with memory disorders such as post-traumatic stress disorder, schizophrenia and psychosis.

"We can now devise new drugs or behavioural strategies that can treat these memory problems in the knowledge that we won't overwrite our experiences," she added.

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Story Source:

The above post is reprinted from materials provided by Cardiff University.Note: Materials may be edited for content and length.

Source:http://bit.ly/1IJ8ZbC

A Theory of Gravitation in Flat Space-Time

Authors:
Walter Petry, Mathematisches Institut der Universitaet Duesseldorf, Duesseldorf, Germany
Description:
The theory of gravitation uses a flat space-time metric, e.g., the pseudo-Euclidean geometry. The gravitational field is described by a tensor of order 2 (potentials) which satisfies covariant (relative to the metric) differential equations of order 2. The left hand side of the differential equations is the total energy-momentum tensor of matter and the gravitational field. The theory is a field theory in analogy to the equations of Maxwell for Electrodynamics and not a geometrical description of gravitation. Applications: The results of the theory agree for weak gravitational field with those of general relativity to the measurable order but for strong gravitational fields are differences, e.g. in the beginning of the universe. The space is flat by the theory. There are non-singular cosmological models, i.e., there is no big bang but the universe may be very hot in the beginning. The universe contracts to a small positive value and then it expands for all times. A new interpretation of a non-expanding universe can also be given. A modified Hubble law is also received in agreement with the results of Arp who states that there are in the universe nearby quasars with quite different redshifts. In addition, post- Newtonian approximations in the matter dominated universe can give large density contrasts. This is important to explain the large scale-structures in the universe, e.g. galaxies, etc. We need no inflation because the space is flat and not curved.

Read this book online:http://bit.ly/1CHNdcq

An Alarm Pheromone May Be Released by Defeated Competitors: A Possible Indicator of Danger

Authors:
Ana G. Gutiérrez-García^1, 2, Carlos M. Contreras^2, 3, *, Remedios Mendoza-López⁴, José Madrigal-Madariaga²

Abstract: Among many species, the establishment of hierarchical relations contains a highly ritualized behavioral context accompanied by the delivery of volatile agents, namely ketones and aldehydes, into environment. These substances act as signals contributing to defining and maintaining social hierarchies. Among mammals, some volatile compounds are released into the environment to report the presence of danger or conflict to conspecifics. For example, rats release an alarm pheromone, 2-heptanone, through their urine when subjected to physical stress. However, it is unknown whether some similarity occurs in human being, in spite that many possible alarm compounds have been identified in human fluids, including 2-heptanone. Contact sports may represent a situation of psychosocial interaction in which some hierarchy is established at the end of the contest. In such a case, the first match in martial arts competitions represents a natural model that is seemingly useful for studying alarm conditions in humans since there are two outcomes, winner and non-winner and after a stressful situation represented by contest, some kind of hierarchy is established. The present study measured urinary concentrations of 2-heptanone using gas chromatography-mass spectrometry and applied anxiety measures (State-Trait Anxiety Inventory, STAI) in a sample of healthy student athletes. Compared with martial-arts winners, the characteristics of the non-winners included an increase in their urinary 2-heptanone content (F_2,18 = 5.541, p < 0.01), with no changes in anxiety scores (STAI-T: F_2,18 = 0.052, p = 0.949; and STAI-S: F_2,18 = 1.083, p = 0.360). The production of this ketone seems to be related with metabolic routes of fatty acids involving the participation of the so called stress hormones that may lead to an increase in the lipolysis of fatty acids and production of their metabolites, and among them, 2-heptanone. The increased release of 2-heptanone at the end of the match in non-winners may be interpreted as the release of an alarm signal that indicates imminent danger, similar to the occurrence in other species.

Keywords: Anxiety, 2-heptanone, Martial Arts, Winners, Tournament, Urine

Introduction

In animals that live in groups, confrontations are part of everyday life and occur within a highly ritualized behavioral context [1,2], leading to the establishment of hierarchical relations but producing a considerable degree of stress, namely in defeated individuals [3]. Some volatile odoriferous substances are released by rodents in corporal fluids and act as signals that contribute to the establishment and maintenance of social hierarchies [4,5]. The preputial gland of dominant male rodents releases two ketones [6], one of which, 2-heptanone, is able to produce anxiety in another receptor conspecific [7].

In primates, some chemical signals are also released in urine during confrontations between males that compete for dominance in the hierarchy or between females that compete for food resources [8]. However, few studies have investigated the role of chemical signals in humans. Contact sports represent a ritualized conflict situation between contenders who are subjected to considerable stress [9,10]. Martial arts competitions may serve as a natural model of social interaction, in which a highly ritualized conflict situation occurs. After physical contact, in most cases, only one winner is possible, thus establishing a type of hierarchy.

Unknown are whether odoriferous substances, identified as alarm pheromones [11], are released by competitors of contact sports and whether urinary excretion is related to the result of the contest. We hypothesized that during martial arts competitions, healthy humans release chemical danger or warning signals. We compared the delivery of urinary 2-heptanone between winners and non-winners in combat sports and associated the results with measurements of anxiety a few minutes prior to the first combat in the tournament, again, a few minutes after the competitors knew the results of the first combat, and 1 week after the tournament.

Read the full article here:http://bit.ly/1ePe2zA

Astronomers discover closest super-Earth

Using NASA’s Spitzer Space Telescope, astronomers have discovered the nearest rocky planet outside our solar system, Astronomy magazine reports. Even though it is larger than Earth and too close to the star to be habitable, astronomers believe this super-Earth, named HD 219134b, might be a potential gold mine for science data for decades to come. This exoplanet is merely 21 light-years away from us, practically a next-door neighbor in astronomical terms. 
That's great news for us, right? If you want the original article, click here:http://bit.ly/1Uh7utx

American Journal of Polymer Science and Technology

The journal will publish peer-reviewed open access English language articles that bridge the gap between research and patenting of an invention, targeting a broad audience of academic and industrial researchers, as well as the increasingly important world of scientists and engineers at start-up companies. The journal also will publish significant advances in polymer science, including chemistry, physical chemistry, physics and material science.
About this journal:

The scope of the journal provides a medium for publication of substantial and original papers, and short communications which focus on Research of Polymers and developments. The journal aims to publish papers with significance to an international audience, containing substantial novelty and scientific impact. The journal will consider articles on the following:

• • Functional polymers
• • Polymer composites and blends
• • Semiconductors
• • Polymer membranes
• • Hydrogels
• • Radiation synthesis and modification of different type of polymers
• • Potential application of polymers in different fields such as industrial, biomedical, agricultural
• Submit your paper about any of these topic in this journal, publish your scientific paper online:http://bit.ly/1MD0QN4