MITIGATING THE INFLUENCE OF DENSE OIL FIRES ON FREE-SPACE OPTICAL COMMUNICATION

This study estimates the performance of a free space optical system (FSO) affected by air pollutants from oil fires. Simulations are performed to evaluate the reliability of optical propagation according to the length of the FSO channels under two beam angle angles. The proposed FSO system parameters such as the Q-factor, BER and reception capacity are successfully used to reduce channel loss. Results demonstrate that the proposed FSO link performs satisfactorily when the divergence angle is 1 mrad and the distance is from 0.5 km to 0.9 km. Q-factor and receiving power decrease when the divergence angle of beam increases to 2 mrad, and a link is achieved when the distance is from 0.5 km to 0.7 km. The eye diagram is used to evaluate and confirm the quality of received data. An eye opening is observed at 0.5 km for both divergence angles. Then, the eye completely closes at 1 km for 2 mrad, thereby degrading the performance. Therefore, these results can be conducted for similar systems optimization options by applying our analysi

Concepto de aristas múltiples empleado para esteganografía de imagen

Digital Steganography means hiding sensitive data inside a cover object ina way that is invisible to un-authorized persons. Many proposed steganography techniques in spatial domain may achieve high invisibility requirement but sacrifice the good robustness against attacks. In some cases, weneed to take in account not just the invisibility but also we need to thinkabout other requirement which is the robustness of recovering the embedded secrete messages. In this paper we propose a new steganoraphicscheme that aims to achieve the robustness even the stego image attackedby steganalyzers. Furthermore, we proposed a scheme which is more robust against JPEG compression attack compared with other traditionalsteganography schemes

Adiabatic Formation of Rydberg Crystals with Chirped Laser Pulses

Ultracold atomic gases have been used extensively in recent years to realize textbook examples of condensed matter phenomena. Recently, phase transitions to ordered structures have been predicted for gases of highly excited, 'frozen' Rydberg atoms. Such Rydberg crystals are a model for dilute metallic solids with tunable lattice parameters, and provide access to a wide variety of fundamental phenomena. We investigate theoretically how such structures can be created in four distinct cold atomic systems, by using tailored laser-excitation in the presence of strong Rydberg-Rydberg interactions. We study in detail the experimental requirements and limitations for these systems, and characterize the basic properties of small crystalline Rydberg structures in one, two and three dimensions.Comment: 23 pages, 10 figures, MPIPKS-ITAMP Tandem Workshop, Cold Rydberg Gases and Ultracold Plasmas (CRYP10), Sept. 6-17, 201

Left ventricular pseudo-aneurysm: Do not make the same mistake

The differentiation between left ventricular pseudo-aneurysm and true aneurysm is sometimes difficult and there are some pitfalls in the process of making the right diagnosis. Correct diagnosis has considerable effect on the outcome and management of the patients. We report the case of 59-year-old man who referred to the emergency department with complaints of lower extremity edema and dyspnea on exertion. In his past medical history, he had been diagnosed with post-myocardial infarction and apical true aneurysm four months before his arrival at the emergency ward. The patient was under strict medical follow-up for his condition. Echocardiography was conducted in the emergency ward, and it revealed a huge apical pseudo-aneurysm, which had been miss-diagnosed in the past echocardiographic examination. We herein seek to address this issue and underscore the pitfalls in making the correct and necessary distinction between these two not so uncommon entities

Making a symbolic gesture: a qualitative examination of self-immolation in Iran

Self-immolation is one of the most dramatic methods of committing suicide. Some regions in Iran have a high prevalence of suicide by this method. This study aims to understand and explore the experience of self-immolated women in Iran. Twenty women have interviewed in the burns centers of three different cities immediately the following hospitalization due self-immolation, and the data was analyzed using conventional content analysis. The results were categorized in three main categories: Cultural background and preparing the stage, making a symbolic gesture and events of the day of the incident. Making a symbolic gesture consists of the critical elements of self-immolation, including the presence of significant others, dramatic presentation of misery, bringing an end to misfortune, proof of innocence, creating a sense of compassion or guilt and inspiration from similar cases. The social situation of women in Iran is contributing to self-immolation through feelings of anger and helplessnes

Recent Searches for the Radio Lines of NH_3 in Comets

Radio observations in the ammonia inversion lines of four comets, C/2001 A2 (LINEAR), 153P/Ikeya-Zhang, C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), were performed at the Effelsberg 100-m Radio Telescope during their respective close approaches to Earth. None of the four lowest energy metastable lines (J,K=J),J=1--4, could be detected in these comets. We derive the following 3 sigma upper bounds on the NH_3 production rate, and c omparing to the corresponding water production rates, percentage NH_3 abundances relative to H_2O: Q(NH_3) < 1.9x10^26 s^-1 (0.63%) for C/2001 A2 (LINEAR), Q(NH_3) < 2.7x10^26 s^-1 (0.13%) for C/2001 Q4 (NEAT), Q(NH_3) < 2.3x10^27 s^-1 (0.74%) for C/2002 T7 (LINEAR) and Q(NH_3) <= 6.3x10^26 s^-1 (0.63%) for Comet 153P/Ikeya-Zhang. At 0.74% or less, the ammonia-to-water ratios are factors of 2 below the value for C/1995 O1 (Hale-Bopp) and 1P/Halley, suggesting chemical diversity between comets. The 18-cm lines of OH were clearly detected in the two comets observed during the 2004 campaign, thereby validating the cometary ephemerides.Comment: 8 pages, 3 figure

Key-Private Proxy Re-Encryption

Proxy re-encryption (PRE) allows a proxy to convert a ciphertext encrypted under one key into an encryption of the same message under another key. The main idea is to place as little trust and reveal as little information to the proxy as necessary to allow it to perform its translations. At the very least, the proxy should not be able to learn the keys of the participants or the content of the messages it re-encrypts. However, in all prior PRE schemes, it is easy for the proxy to determine between which participants a re-encryption key can transform ciphertexts. This can be a problem in practice. For example, in a secure distributed file system, content owners may want to use the proxy to help re-encrypt sensitive information *without* revealing to the proxy the *identity* of the recipients. In this work, we propose key-private (or anonymous) re-encryption keys as an additional useful property of PRE schemes. We formulate a definition of what it means for a PRE scheme to be secure and key-private. Surprisingly, we show that this property is not captured by prior definitions or achieved by prior schemes, including even the secure *obfuscation* of PRE by Hohenberger, Rothblum, shelat and Vaikuntanathan (TCC 2007). Finally, we propose the first key-private PRE construction and prove its security under a simple extension of the Decisional Bilinear Diffie Hellman assumption and its key-privacy under the Decision Linear assumption in the standard model

A canine model of Cohen syndrome: Trapped Neutrophil Syndrome

<p>Abstract</p> <p>Background</p> <p>Trapped Neutrophil Syndrome (TNS) is a common autosomal recessive neutropenia in Border collie dogs.</p> <p>Results</p> <p>We used a candidate gene approach and linkage analysis to show that the causative gene for TNS is <it>VPS13B</it>. We chose <it>VPS13B </it>as a candidate because of similarities in clinical signs between TNS and Cohen syndrome, in human, such as neutropenia and a typical facial dysmorphism. Linkage analysis using microsatellites close to <it>VPS13B </it>showed positive linkage of the region to TNS. We sequenced each of the 63 exons of <it>VPS13B </it>in affected and control dogs and found that the causative mutation in Border collies is a 4 bp deletion in exon 19 of the largest transcript that results in premature truncation of the protein. Cohen syndrome patients present with mental retardation in 99% of cases, but learning disabilities featured in less than half of TNS affected dogs. It has been implied that loss of the alternate transcript of <it>VPS13B </it>in the human brain utilising an alternate exon, 28, may cause mental retardation. Mice cannot be used to test this hypothesis as they do not express the alternate exon. We show that dogs do express alternate transcripts in the brain utilising an alternate exon homologous to human exon 28.</p> <p>Conclusion</p> <p>Dogs can be used as a model organism to explore the function of the alternately spliced transcript of VPS13B in the brain. TNS in Border collies is the first animal model for Cohen syndrome and can be used to study the disease aetiology.</p