355 research outputs found

    Modified Newton's Law of Gravitation Due to Minimal Length in Quantum Gravity

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    A recent theory about the origin of the gravity suggests that the gravity is originally an entropic force. In this work, we discuss the effects of generalized uncertainty principle (GUP) which is proposed by some approaches to quantum gravity such as string theory, black hole physics and doubly special relativity theories (DSR), on the area law of the entropy. This leads to a Area\sqrt{Area}-type correction to the area law of entropy which imply that the number of bits NN is modified. Therefore, we obtain a modified Newton's law of gravitation. Surprisingly, this modification agrees with different sign with the prediction of Randall-Sundrum II model which contains one uncompactified extra dimension. Furthermore, such modification may have observable consequences at length scales much larger than the Planck scale.Comment: 12 pages, no figures, references adde

    Security Measures in Mobile Commerce: Problems and Solutions

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    Due to the advent of the Internet, electronic business transactions have exploded around the globe. Along with the Internet, wireless technology has exponentially developed as well. Today, new technologies that allow mobile (cellular) phones and other handheld devices to access the Internet have made wireless business transactions possible. This phenomenon is known as mobile commerce or M-Commerce. It has been predicted that the number of mobile phones connected to the mobile Internet will exceed the number of Internet-connected PCs before 2007. The mobile phone will therefore become the most prevalent device for accessing the Internet. Several industry analysts predict that Mcommerce will constitute a multibillion dollar business by 2005. However, M-Commerce brings new challenges in providing information security as information travels through multiple networks often across wireless links. What must be done to secure financial transactions via mobile commerce? Generally speaking, M-Commerce creates more security concerns than traditional E-Commerce. In this paper, security measures in M-Commerce, wireless security, and the application of cryptography for key generation, authentication, digital signature and digital certificate are discussed

    A proposal for testing Quantum Gravity in the lab

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    Attempts to formulate a quantum theory of gravitation are collectively known as {\it quantum gravity}. Various approaches to quantum gravity such as string theory and loop quantum gravity, as well as black hole physics and doubly special relativity theories predict a minimum measurable length, or a maximum observable momentum, and related modifications of the Heisenberg Uncertainty Principle to a so-called generalized uncertainty principle (GUP). We have proposed a GUP consistent with string theory, black hole physics and doubly special relativity theories and have showed that this modifies all quantum mechanical Hamiltonians. When applied to an elementary particle, it suggests that the space that confines it must be quantized, and in fact that all measurable lengths are quantized in units of a fundamental length (which can be the Planck length). On the one hand, this may signal the breakdown of the spacetime continuum picture near that scale, and on the other hand, it can predict an upper bound on the quantum gravity parameter in the GUP, from current observations. Furthermore, such fundamental discreteness of space may have observable consequences at length scales much larger than the Planck scale. Because this influences all the quantum Hamiltonians in an universal way, it predicts quantum gravity corrections to various quantum phenomena. Therefore, in the present work we compute these corrections to the Lamb shift, simple harmonic oscillator, Landau levels, and the tunneling current in a scanning tunneling microscope.Comment: v1: 10 pages, REVTeX 4, no figures; v2: minor typos corrected and a reference added. arXiv admin note: has substantial overlap with arXiv:0906.5396 , published in a different journa

    Acute oral toxicity of two products from a microbial pest control agent (Beauveria bassiana) on physiological status aspects of male albino rats

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    Background: Synthetic pesticides have accumulated in environment causing harm to humans and ecosystems. As a result, the use of biopesticides in agriculture and public health has expanded as a substitute for traditional pesticides. Purpose: To investigate the acute oral toxicity of Beauveria bassiana, on physiological status aspects of male rats. Material and Methods: Metabolic crude (MC), and wettable powder formulation (2.5% WP) from the local isolate of B. bassiana (AUMC 9896) were tested on adult Sprague Dawley (SD) male rats by single oral dose. Results: There was no evidence of death or toxic symptoms in any of the treated groups. In contrast, each product caused a significant increase in the body weight gain and relative liver weights of B. bassiana-exposed male and reduced the brain somatic index with WP only as compared to the control. The studied bioinsecticide also caused a substantial rise in total erythrocyte and absolute differential leucocyte counts, while red blood cell distribution width (RDW) and platelet count (Plt) were decreased significantly. Furthermore, male rats exposed to both types of B. bassiana, aspartate aminotransferases (AST), total protein (TP), albumin (Alb), AST/ALT, triglyceride, and very low-density lipoprotein cholesterol (VLDL) were elevated compared to the untreated group, whereas alkaline phosphatase (ALP) activity, globulin (Glb), Alb/Glb, urea content, and low-density lipoprotein cholesterol (LDL) count fluctuated between increased and decreased. Also, B. bassiana-treated rats had lower serum cholesterol and high-density lipoprotein cholesterol levels (HDL) values.Conclusion: These results suggest that both treatments have slight effects on complete blood count (CBC) of treated male rats and marked effect on liver function, lipid profile, body weight gain and somatic index of the liver and brain

    Effect of the Generalized Uncertainty Principle on Post-Inflation Preheating

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    We examine effects of the Generalized Uncertainty Principle, predicted by various theories of quantum gravity to replace the Heisenberg's uncertainty principle near the Planck scale, on post inflation preheating in cosmology, and show that it can predict either an increase or a decrease in parametric resonance and a corresponding change in particle production. Possible implications are considered.Comment: v1: 9 pages, revtex4, no figures, accepted for publication in JCAP; v2: one reference added and various cosmetic (but no physics) changes to match published versio

    Detection of equid herpesviruses among different Arabian horse populations in Egypt

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    Equid herpesviruses (EHVs) threaten equine health and can cause significant economic losses to the equine industry worldwide. Different equid herpesviruses, EHV‐1, EHV‐2, EHV‐4 and EHV5 are regularly detected among horse populations. In Egypt, monitoring is sporadic but EHV‐1 or EHV‐4 have been reported to circulate in the horse population. However, there is a lack of reports related to infection and health status of horses, likely due to the absence of regular diagnostic procedures. In the current study, the circulation of four infectious equid herpesviruses (EHV‐1, EHV‐2, EHV‐4 and EHV‐5) among different Arabian horse populations and donkeys residing the same farm was monitored. Different samples were collected and DNA was extracted and subjected to quantitative (q)‐PCR to detect the four equid herpesviruses using specific primers and probes. Antibody titres against EHV‐1 and EHV‐4 were tested using virus neutralization test and type‐specific ELISA. The results showed that EHV‐1, EHV‐2, EHV‐4 and EHV‐5 are endemic and can be a continuous threat for horses in the absence of vaccination programs and frequent virus reactivation. There is an urgent need for introduction of active regular surveillance measures to investigate the presence of different equid herpesviruses, and other equine viral pathogens, in various horse populations around Egypt and to establish a standardized cataloguing of equine health status

    Minimal Length in Quantum Gravity, Equivalence Principle and Holographic Entropy Bound

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    A possible discrepancy has been found between the results of a neutron interferometry experiment and Quantum Mechanics. This experiment suggests that the weak equivalence principle is violated at small length scales, which quantum mechanics cannot explain. In this paper, we investigated whether the Generalized Uncertainty Principle (GUP), proposed by some approaches to quantum gravity such as String Theory and Doubly Special Relativity Theories (DSR), can explain the violation of the weak equivalence principle at small length scales. We also investigated the consequences of the GUP on the Liouville theorem in statistical mechanics. We have found a new form of invariant phase space in the presence of GUP. This result should modify the density states and affect the calculation of the entropy bound of local quantum field theory, the cosmological constant, black body radiation, etc. Furthermore, such modification may have observable consequences at length scales much larger than the Planck scale. This modification leads to a \sqrt{A}-type correction to the bound of the maximal entropy of a bosonic field which would definitely shed some light on the holographic theory.Comment: 12 pages, no figures, recommended to be published at Class.Quant.Gra
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