Physics Research Papers - Academia.edu (original) (raw)

Recognizing the imperiled status of biodiversity and its benefit to human well-being, the world's governments committed in 2010 to take effective and urgent action to halt biodiversity loss through the Convention on Biological Diversity's "Aichi Targets". These targets, and many conservation programs, require monitoring to assess progress toward specific goals. However, comprehensive and easily understood information on biodiversity trends at appropriate spatial scales is often not available to the policy makers, managers, and scientists who require it. We surveyed conservation stakeholders in three geographically diverse regions of critical biodiversity concern (the Tropical Andes, the African Great Lakes, and the Greater Mekong) and found high demand for biodiversity indicator information but uneven availability. To begin to address this need, we present a biodiversity "dashboard"--a visualization of biodiversity indicators designed to enable tracking o...

- by
- •
- Engineering, Physics, Chemistry, Biology

Coherent-population-trapping resonances within the degenerate two-level system of the F=2→F'=1 transition of the 87 Rb D1 line were investigated in an uncoated Rb vapor cell by means of level-crossing-type experiments. Tuning over the two-photon resonance is achieved sweeping a magnetic field around zero value. The influence of transverse magnetic fields on the amplitude and the width of the resonances, recorded in fluorescence and absorption, were investigated in the cases of excitation with linear, circular, and elliptical laser light polarization. A theoretical analysis was performed for the case of linearly polarized excitation, the results of which are in good agreement with the experiment.

- by Georgy Todorov
- •
- Applied Mathematics, Physics, Magnetic field, Coherent Population Trapping
- by José M M Senovilla
- •
- Mathematics, Lie Algebra, Physics, Mathematical Sciences

The activation of the G-protein transducin (Gt) by rhodopsin (Rho) has been intensively studied for several decades. It is the best understood example of GPCR activation mechanism and serves as a template for other GPCRs. The structure of the Rho/G protein complex, which is transiently formed during the signaling reaction, is of particular interest. It can help understanding the molecular details of how retinal isomerization leads to the G protein activation, as well as shed some light on how GPCR recognizes its cognate G protein. The native Rho/Gt complex isolated from bovine retina suffers from low stability and loss of the retinal ligand. Recently, we reported that constitutively active mutant of rhodopsin E113Q forms a Rho/Gt complex that is stable in detergent solution. Here, we introduce methods for a large scale preparation of the complex formed by the thermo-stabilized and constitutively active rhodopsin mutant N2C/M257Y/D282C(RhoM257Y) and the native Gt purified from bovine...

- by Gebhard F X Schertler and +3
- •
- Engineering, Physics, Chemistry, Biology
- by Julie Gore
- •
- Psychology, Cognitive Science, Physics, Social Cognition
- by Michael Lindenfeld
- •
- Physics

Since the advent of quantum mechanics, our fundamental physical descriptions of the universe have included a strong element of randomness. While this randomness goes against aspirations to comprehend a fundamental, deterministic order underlying science, physicists have mostly learned to accept randomness, fashioning a picture of the universe according to which order and chance are two sides of the same coin, and which all we know appears subject to physical descriptions combining rules and randomness. Broader cultural understandings of science, however, have not yet come to terms with the randomness in physics. Debates concerning science and religion, in particular, have been slow in accepting the consequences of fundamental randomness, partly because these are difficult to reconcile with religious intuitions about design and purpose.

- by Taner Edis
- •
- Physics, Science and Religion, Hypercomputation, Randomness

Many authors noted that the principle of relativity together with space-time homogeneity and isotropy restrict the form of the coordinate transformations from one inertial frame to another to being Lorentz-like. A free parameter in these equations, k, plays the part of c −2 in special relativity. It is usual to claim that k is determined by experiment and hence, that special relativity does not need the postulate of constancy of the speed of light. I analyze how one would go about determining k empirically and find that all methods suffer from severe problems without further assumptions, none as simple and elegant as the postulate of constancy of the speed of light. I conclude that while the formal structure of the transformation equations can be determined without appeal to the second postulate, the theory is left without physical content if we ignore this postulate. Specifically, evaluating k requires creating a signal that travels identically in opposite directions or ensuring th...

- by Alon Drory
- •
- Physics
- by Margaret Niess
- •
- Physics, Quantum Mechanics, Mathematical Sciences, Physical sciences
- by Yuval Beck
- •
- Geography, Physics, Analytical Model, Electric Field

Galileo once said that one cannot understand the universe without comprehending its language: mathematics. Unfortunately, most individuals will approach physical sciences with dread, due in part to the difficulty with speaking the language of the universe, and for this reason may fail to perceive its breathtaking beauty. When we look deeper than the letter of reason, we encounter a flow of imagination that appears to be integral to the cosmos. The Enlightenment of the 18th century was an Age of Reason that deeply shaped our modern society. By following the movement of ideas from classical physics to quantum mechanics, passing by chaos theory and Einstein’s special and general relativity, it is argued that a new Enlightenment might be in sight, an Age of Imagination, wherein the creatures that we are will consciously re-enter the flow of imagination. This exploration concerns classical physics and its repression of imagination; the difficult emergence of deterministic chaos is viewed as a return of what was left behind, so to speak: the shadow of reason.

- by Christophe Le Mouël
- •
- Physics, Jungian and post-Jungian psychology, Imagination

Nancy Cartwright’s most recent monograph: Nature, the Artful Modeler: Lectures on Laws, Science, How Nature Arranges the World and How We Can Arrange It Better presents the state of the art in the philosophy of science literature. Here, we are presented with the most coherent form of Cartwright’s views to date, combining building blocks she and other Cartwrightians have meticulously crafted throughout the last decades. We are thus presented with a book containing not only incredibly rich work on a diversity of topics spanning several decades, but also a number of novel ideas that will leave an impact on the philosophy of science in the decades to come.

- by Walter Veit
- •
- Physics, Philosophy of Science, Social Sciences, Graphical Models
- by Knut Solna
- •
- Physics, Homogenization, High Frequency, Classical Physics
- by Reiner Schultheiss Dr.
- •
- Physics, Biophysics, Medicine, Clinical Sciences
- by Thomas Pettke
- •
- Pharmacology, Biochemistry, Bioinformatics, Evolutionary Biology

Quantum teleportation has been introduced by Benett et al. and dis cussed by a number of authors in the framework of the singlet state. Recentl y, a rigorous formulation of the teleportation problem of arbitrary quantum states by means of quantum channel was given in [IOS] based on the general c hannel theoretical formulation of the quantum gates introduced in [OW]. In t his note we discuss a generalization of the scheme proposed in [IOS] and we give a general method to solve the teleportation problem in spaces of arbitr ary finite dimensions.

- by Luigi Accardi
- •
- Physics, Quantum Physics, Quantum Teleportation, Quantum Gate

O presente trabalho teve por objetivos avaliar a composição de rizomas do lírio-do-bejo (Hedychium coronarium) e isolar e caracterizar seu amido, por meio de análises físicas e físico-químicas. A composição química dos grânulos de amido isolados dos rizomas também foi determinada, bem como o formato, tamanho, distribuição de tamanho de partícula por difração a laser, viscosidade de pasta em analisador rápido de viscosidade, poder de inchamento, índice de solubilidade em água, propriedade térmica por calorimetria diferencial de varredura e cristalinidade por difração de raios X. Observou-se que os rizomas apresentaram elevado teor de água e baixos teores de matéria graxa, carboidratos, cinzas, proteínas e fibras. Os rizomas de lírio-do-brejo apresentam-se inadequados para produção de amido, devido ao baixo teor de matéria seca (17,3%), com 21,97% de amido, bem como fibras longas e látex, que dificultam a extração do amido. O amido extraído apresentou pureza de 99,2%, com 37,2% de ami...

- by Wellington F E R R E I R A Moura
- •
- Mathematics, Physics, Thermodynamics, Chemistry
- by Yashowanta N. Mohapatra
- •
- Physics, Materials Science, Chemistry, Physical Chemistry
- by Shankar Prinja
- •
- Engineering, Physics, Chemistry, Health Care
- by Fernando Ernesto
- •
- Physics
- by Azhari Fauzan
- •
- Physics
- by da fang
- •
- Physics
- by Gordon Warren
- •
- Engineering, Physics, Chemistry, Skeletal muscle biology
- by Jie Ge
- •
- Chemical Engineering, Physics, Materials Science, Solid State Physics

Fermat’s Last Theorem is proved using elementary arithmetic.
Connection of this proof to Gӧdel’s Incompleteness Theorem is mentioned.

- by RICHARD WAYTE
- •
- Physics
- by Amanda Guedes
- •
- Physics
- by Ahti Lampinen
- •
- Psychology, Physics, Philosophy, Biology

AS IT SAYS, WITH PICTURES AND TECHNICAL EXPLANATIONS.

- by MIKE EMERY
- •
- Hinduism, History, Environmental Science, Physics
- by alifta devi
- •
- Mechanical Engineering, Microbiology, Oceanography, Physics

This paper updates earlier thoughts by the author on a putative propulsion system. The concept was based around static electromagnetic momentum, as expounded in the "Feynman Disk" and experimentally verified by Graham and Lahoz. That said, naïve static electromagnetic momentum schemes to achieve linear translation are defeated by "hidden momentum" mechanisms, so too are simple arrangements just cycling the fields; we shall survey the flaws in their arguments. It may however be possible to achieve linear translation by means of arrangements of torques with a novel mechanism to break the symmetry of forces (or torques) on the second half of the cycle as the field is switched off. At the time of earlier presentation no mechanism could be found to explain the momentum balance for the process but it was believed that momentum was being given to the zero-point of the field. We show that it is possible to dump angular momentum and thence linear momentum to the ground state by standard quantum analysis of the EM field. None of this violates the conservation of momenergy.

- by Remi Cornwall
- •
- Engineering, Physics, Theoretical Physics, Electromagnetism
- by David Gurwitz
- •
- Engineering, Genetics, Physics, Chemistry
- by web tierra
- •
- Earth Sciences, Physics

The Soviet historian and philosopher of science Boris Hessen (English spelling also Gessen) is well known for the paper “On the Social and Economic Roots of Newton’s Principia” he gave in 1931 to the Second International Congress of the History of Science in London. Its focus on the socio-economic aspects of the development of science – later called “externalism”– was regarded as groundbreaking. We present here an English translation of a lecture he gave in Moscow in April 1936, recently discovered in Russian archives, and believed to be one of his last works. He was arrested in August that year, admitting to “participation in counter-revolutionary Trotskyist activity” and “animosity toward Comrade Stalin”. He was subject to torture and eventually executed in December, after denying “creating a terrorist cell at Moscow State University”. The lecture shows that despite being under enormous psychological pressure he coninued working on the history of physics but also returned to the philosophical questions of his earlier writings. We give a brief introduction to the lecture, attempting to place it in its context, and linking to his earlier work on the philosophy of physics from a Marxist standpoint which we have previously translated into English.

- by Chris Talbot
- •
- Physics, Philosophy of Science, Soviet History, History of Science
- by Ma-Li Wong
- •
- Pharmacology, Biochemistry, Bioinformatics, Evolutionary Biology
- by Lorena Montoya
- •
- Physics, Psicología

A logical physical ontology is code theory, wherein reality is neither deterministic nor random. In light of Conway and Kochens' free will theorem and strong free will theorem, we discuss the plausibility of a third axiomatic option-geometric language; the code theoretic axiom. We suggest free will choices at the syntactically free steps of a geometric language of space-time form the code theoretic substrate upon which particle and gravitational physics emerge.

- by Klee Irwin
- •
- Physics, Theoretical Physics, Quantum Physics, Ontology

Introducao: O termo disturbios respiratorios do sono (DRS) refere-se a padroes de respiracao anormal ou reducao anormal da troca gasosa que ocorrem durante o sono. Incluem a apneia obstrutiva do sono, a hipoventilacao e a apneia central do sono. Quando nao diagnosticados e nao tratados, os DRS constituem um grave problema de saude publica, dada a sua alta prevalencia e suas graves consequencias para a saude. A pressao positiva na via aerea (PAP) e o tratamento de primeira linha para os DRS moderados a graves. Muitas vezes, o uso da PAP requer a associacao de outras estrategias ventilatorias, ou ate mesmo o uso de oxigenoterapia suplementar por doencas concomitantes aos DRS. Objetivo: abordar aspectos importantes dos DRS, incluindo: conceitos, implicacoes clinicas, metodos diagnosticos e opcoes de tratamentos. Resultados e Conclusoes: O papel do fisioterapeuta, dentro da equipe multidisciplinar que atua para o tratamento dos DRS, e discutido amplamente, inclusive como sendo o profiss...

- by Flávia Nerbass and +1
- •
- Physics
- by Carole Garofalo and +3
- •
- Engineering, Physics, Chemistry, Biology

What does this little equation have to do with the LHC? Key words: hierarchy of energy, Gordon's Theory of Everything, " smallest something " , Ruby Slipper Conundrum, Gordon Omnipresent Dot, GOD entities, the GOD Equation, the... more

- by Scott S Gordon
- •
- Physics, Cosmology (Physics), Quantum Gravity, Dark Energy

PT. Kaleng Raya adalah sebuah perusahaan yang bergerak pada bidang pembuatan kaleng makanan. PT. Kaleng Raya merupakan perusahaan no 1 di Indonesia dalam hal memproduksi kaleng makanan. Semua urusan proses produksi yang ada di perusahaan tersebut terletak di daerah raya pilang, kota Siodarjo. Akibat banyaknya konsumen yang bekerja sama pada perusahaan ini, membuat perusahaan harus tepat waktu dalam mengirimkan produknya tersebut. Akan hal tersebut membuat perusahaan harus mempunyai persediaan bahan baku yang mencukupi agar proses produksi tetap dapat berjalan tanpa harus kehabisan bahan baku. Dalam menghadapi hal ini membuat perusahaan harus mempunyai dasar perencanaan persediaan yang baik, agar tidak terjadi penumpukan bahan baku serta mengantisipasi adanya kehabisan bahan baku. Terdapat dua metode untuk dapat membantu perusahaan dalam perencanaan persedian yaitu metode adalah Economic Order Quantity (EOQ), dan Periodic Review System (PRS). Kedua metode tersebut dapat bisa saling d...

- by Billy Anggoro
- •
- Physics, Industrial Engineering

In this paper, a study on the batch processing and characterization of microcellular foamed high-density polyethylene (HDPE/iPP) blends is reported. A microcellular plastic is a foamed polymer with a cell density greater than 109 cells/cm3 and fully grown cells smaller than 10 µm. Recent studies have shown that the morphology and crystallinity of semicrystalline polymers have a great influence on the solubility and diffusivity of the blowing agent and on the cellular structure of the resulting foam in microcellular batch processing. In this research, blends of HDPE and iPP were used to produce materials with variety of crystalline and phase morphologies to enhance the subsequent microcellular foaming. It was possible to produce much finer and more uniform foams with the blends than with neat HDPE and iPP. Moreover, the mechanical properties and in particular the impact strength of the blends were significantly improved by foaming.
(citation # 293)

- by Saeed Doroudiani, PhD, P.Eng.
- •
- Chemical Engineering, Physics, Chemistry, Physical Chemistry

Minkowski famously introduced the concept of a space-time continuum in 1908, merging the three dimensions of space with an imaginary time dimension $ i c t ,withtheunitimaginaryproducingthecorrectspacetimedistance, with the unit imaginary producing the correct spacetime distance ,withtheunitimaginaryproducingthecorrectspacetimedistance x^2 - c^2 t^2 ,andtheresultsofEinstein′sthenrecentlydevelopedtheoryofspecialrelativity,thusprovidinganexplanationforEinstein′stheoryintermsofthestructureofspaceandtime.AsanalternativetoaplanarMinkowskispace−timeoftwospacedimensionsandonetimedimension,wereplacetheunitimaginary, and the results of Einstein's then recently developed theory of special relativity, thus providing an explanation for Einstein's theory in terms of the structure of space and time. As an alternative to a planar Minkowski space-time of two space dimensions and one time dimension, we replace the unit imaginary ,andtheresultsofEinstein′sthenrecentlydevelopedtheoryofspecialrelativity,thusprovidinganexplanationforEinstein′stheoryintermsofthestructureofspaceandtime.AsanalternativetoaplanarMinkowskispace−timeoftwospacedimensionsandonetimedimension,wereplacetheunitimaginary i = \sqrt{-1} ,withtheCliffordbivector, with the Clifford bivector ,withtheCliffordbivector \iota = e_1 e_2 $ for the plane that also squares to minus one, but which can be included without the addition of an extra dimension, as it is an integral part of the real Cartesian plane with the orthonormal basis $ e_1 $ and $ e_2 $. We find that with this model of planar spacetime, using a two-dimensional Clifford multivector, the spacetime metric and the Lorentz transformations follow immediately as properties of the algebra. This also leads to momentum and energy being represented as components of a multivector and we give a new efficient derivation of Compton's scattering formula, and a simple formulation of Dirac's and Maxwell's equations. Based on the mathematical structure of the multivector, we produce a semi-classical model of massive particles, which can then be viewed as the origin of the Minkowski spacetime structure and thus a deeper explanation for relativistic effects. We also find a new perspective on the nature of time, which is now given a precise mathematical definition as the bivector of the plane.

- by Nicolangelo Iannella and +1
- •
- Engineering, Physics, Chemistry, Biology

For many years the Fermilab physics program has been dominated by the superconducting Tevatron accelerator producing beams for many fixed target and the proton-antiproton colliding beam experiments CDF and D0. More recently, major experiments have used beam from intermediate accelerators. The MiniBooNE and MINOS experiments use 8 and 120 GeV beam respectively for neutrino oscillation studies. Several other experiments and test beams have also used 120 GeV beam. This paper describes the control system for the accelerator complex that was originally developed for the start of Tevatron operation in 1983. This system is common to all accelerators in the chain, and has been successfully evolved to accommodate new hardware, new software platforms, new accelerators, and increasingly complex modes of operation.

- by Sharon Lackey
- •
- Physics, Control system, Particle Acceleration
- by beni widhianto
- •
- Physics, Laser, Spectroscopy, Photonics

An efficient and new but non-intrusive method to detect the fluctuation in gear load may be the motor current signature analysis (MCSA). In this paper, a multi-stage transmission gearbox (with and without defects) has been studied in order to replace the conventional vibration monitoring by MCSA. It has been observed through FFT analysis that low frequencies of the vibration signatures have sidebands across line frequency of the motor current whereas high frequencies of vibration signature are difficult to be detected. Hence, discrete wavelet transform (DWT) is suggested to decompose the current signal, and FFT analysis is carried out with the decomposed current signal to trace the sidebands of the high frequencies of vibration

- by Dan Gollub
- •
- Pharmacology, Biochemistry, Bioinformatics, Evolutionary Biology