The Internet AS-Level Topology: Three Data Sources and One Definitive Metric

We calculate an extensive set of characteristics for Internet AS topologies extracted from the three data sources most frequently used by the research community: traceroutes, BGP, and WHOIS. We discover that traceroute and BGP topologies are similar to one another but differ substantially from the WHOIS topology. Among the widely considered metrics, we find that the joint degree distribution appears to fundamentally characterize Internet AS topologies as well as narrowly define values for other important metrics. We discuss the interplay between the specifics of the three data collection mechanisms and the resulting topology views. In particular, we show how the data collection peculiarities explain differences in the resulting joint degree distributions of the respective topologies. Finally, we release to the community the input topology datasets, along with the scripts and output of our calculations. This supplement should enable researchers to validate their models against real data and to make more informed selection of topology data sources for their specific needs.Comment: This paper is a revised journal version of cs.NI/050803

Identification, distribution and incidence of viruses in field-grown cucurbit crops of Iran

A survey of viruses in the major cucurbit-growing areas of 17 provinces in Iran was conducted in 2005 and 2006. A total of 1699 leaf samples were collected from melon, squash, cucumber and watermelon plants showing various virus-like symptoms. Screening for 11 cucurbit viruses by double-antibody sandwich ELISA (DAS-ELISA) or RT-PCR, found that 71% of the samples were infected by at least one virus, of which Cucurbit aphid-borne yellows virus (CABYV) was the most common overall, occurring in 49, 47, 40, and 33% of cucumber, squash, melon, and watermelon samples respectively. The second most common virus on melon and watermelon was Watermelon mosaic virus (WMV) (incidence 30–33%); on cucumber, Cucumber mosaic virus (CMV)(33%); and on squash, Zucchini yellow mosaic virus (ZYMV)(38%). To our knowledge, this is the first report of Melon necrotic spot virus (MNSV) and Zucchini yellow fl eck virus (ZYFV) in Iran. Mixed infections occurred in 49% of symptomatic samples. Mixed infections were relatively frequent in squash (58%) and melon (55%). The most frequent double infections were WMV+CABYV and ZYMV+CABYV in melon, squash and cucumber, followed by WMV+ZYMV. In watermelon, the most frequent double infection was WMV+ZYMV, followed by WMV+CABYV. The high frequency of CABYV, WMV and ZYMV in the samples assayed on all four cucurbit crops and in all areas surveyed, as well as the detection of Watermelon chlorotic stunt virus (WmCSV) and Cucumber vein yellowing virus (CVYV) in northern and southern Iran, suggest that these viruses represent a potential threat to cucurbit crops in Iran

Producing gold nanoparticles from loaded activated carbon and its separation with carbon fiber film formation at the oil/water interface in the acetone- water-sodium chloride system

Abstract Due to the wide spread applications of gold in medicine, electronic computational industries, catalysts, and its special application in biological researches and more over by attention to high cost and complicated production of gold nanoparticles (AuNPs) and in the other hand, the importance of substituting the environmental pollutants such as cyanide compounds in most commonly processes of gold recovery from ores and concentrates, finding a simple, economic and environmental way to achieve AuNPs has to be considered. Because of its large surface area, activated carbon (AC) is used in extracting gold. In this research work a new way has been mentioned for production and separation of AuNPs from loaded AC. By heating loaded AC in the air at 300 for 30 min, gold metal nanoparticles were produced on the surfaces of AC with reducing the gold cyanide complex. The detachment of the AuNPs from AC surfaces was done by two ways: 1. Abrasion of AC by NaCl 2. Using ultrasound; the separation of the detached AuNPs from AC granules abraded by NaCl was done based on the difference between AC and gold density and using water and oil mixture. Effect of abrasion time, salt to carbon weight ratio and prewashed loaded AC conditions on the amount of gold recovered from loaded AC was evaluated in abrasion method. In a novel approach, separation of carbon from gold-containing aqueous solution was done by addition of acetone in mixture and forming carbon microfibers film at the oil/water interface. Acid washing was done to remove impurities after separating carbon from gold-containing solution. As a result, relatively pure AuNPs were obtained after acid washing

Adiponectin as a Protective Factor Against the Progression Toward Type 2 Diabetes Mellitus in Postmenopausal Women.

Serum adiponectin levels have been suggested to be predictors of type 2 diabetes mellitus in diverse populations. However, the relationship between circulating adiponectin levels and the risk of development of type 2 diabetes in postmenopausal women has not been investigated.A total of 382 healthy postmenopausal women who participated in a prospective cohort study were followed for 5.8 years. Type 2 diabetes mellitus was defined according to the criteria set out by the American Diabetes Association. Adiponectin, osteoprotegerin (OPG), and high-sensitivity C-reactive protein (hs-CRP) levels were measured using ELISA.Of 195 women who did not have diabetes at baseline and who were reexamined in the second phase of the study for diabetic status, 35 subjects (17.9%) developed type 2 diabetes mellitus during the 5.8 years follow-up period. The women with type 2 diabetes had lower adiponectin levels than the healthy postmenopausal women. Multiple regression analysis showed that, after adjustments were made for age, cardiovascular risk factors, OPG, and hs-CRP levels, higher baseline adiponectin levels were associated with a lower relative risk (RR) of having type 2 (RR = 0.07, confidence interval [CI]: 0.01-0.66, P = 0.021).Higher baseline adiponectin levels functioned as a predictor of a lower risk of developing type 2 diabetes mellitus among postmenopausal women during a 5.8 years follow-up study. Therefore, it is suggested that elevated adiponectin levels may offer protection against the development of type 2 diabetes mellitus after the menopause

Molecular epidemiology of hepatitis C virus genotypes in Bushehr province, Iran

Background and Objectives: Molecular epidemiology of hepatitis C virus (HCV) is very important for the treatment of hepatitis C infection. The aim of this study was to determine the distribution of HCV genotypes in Bushehr province (South West of Iran). Materials and Methods: A total of 100 patients who were detected as positive for HCV antibody (by using ELISA method and RIBA test) referred to Arya Virology Laboratory between 2007-2009 in order to molecular diagnosis and furthermore virus genotyping. After detection of HCV, RNA genotyping of virus was done by using genotype specific primers. Results: Genotype 1a was found in 49% of the patients and genotype 3a was found in 40% of the patients and 1b in 5% of patients, while the genotype of the virus could not be identified in 5% of the patients. Finally, in 1% of patients coinfection due to 1a-3a genotypes was identified. Conclusion: The dominant genotype of HCV in Bushehr province, Iran, was determined as 1a.with acute hepatitis C ultimately develop chronic infection1. Only a minority of cases of acute HCV recover completely, with spontaneous virus eradication. In most cases the acute infection progresses to chronicity. Chronic HCV infection is defined as an infection that persists for more than 6 months, with or without clinical manifestations of hepatic or extrahepatic disease. Chronic type of this infection can cause cirrhosis, liver failure, and liver cancer. HCV infection is a global health problem and it is estimated that 200 million people of the world population are infected5. The global spread of chronic HCV infection coincided with the widespread use of transfused blood and blood products and with the expansion of intravenous drug use but decreased prior to the wide implementation of anti-HCV screening6. There are at least six major genotypes designated by Arabic numerals and more than 50 subtypes of HCV identified by lower case letters. The different genotypes have different geographic distributions1,4. Genotype determination of HCV is one of the most important factors in order to prediction of the viral persistency, pathogenicity and resistancy to antivirals7. The success and the treatment period of interferon and ribavirin seems to be related to the genotype of virus8. Furthermore, HCV genotyping is a useful tool to determine its molecular epidemiology, as they are indicative of transmission route of infection9,10. There is no published data about the distribution of HCV genotypes from Bushehr province (South West of Iran). Prevalence of HCV genotypes in Bushehr is an issue that is not sufficiently investigated and there is a need, therefore, to study this in detail

Obesity-dependent changes in interstitial ECM mechanics promote breast tumorigenesis.

Obesity and extracellular matrix (ECM) density are considered independent risk and prognostic factors for breast cancer. Whether they are functionally linked is uncertain. We investigated the hypothesis that obesity enhances local myofibroblast content in mammary adipose tissue and that these stromal changes increase malignant potential by enhancing interstitial ECM stiffness. Indeed, mammary fat of both diet- and genetically induced mouse models of obesity were enriched for myofibroblasts and stiffness-promoting ECM components. These differences were related to varied adipose stromal cell (ASC) characteristics because ASCs isolated from obese mice contained more myofibroblasts and deposited denser and stiffer ECMs relative to ASCs from lean control mice. Accordingly, decellularized matrices from obese ASCs stimulated mechanosignaling and thereby the malignant potential of breast cancer cells. Finally, the clinical relevance and translational potential of our findings were supported by analysis of patient specimens and the observation that caloric restriction in a mouse model reduces myofibroblast content in mammary fat. Collectively, these findings suggest that obesity-induced interstitial fibrosis promotes breast tumorigenesis by altering mammary ECM mechanics with important potential implications for anticancer therapies

Scalability and accuracy in a large-scale network emulator

This paper presents ModelNet, a scalable Internet emulation environment that enables researchers to deploy unmodified software prototypes in a configurable Internet-like environment and subject them to faults and varying network conditions. Edge nodes running user-specified OS (operating system) and application software are configured to route their packets through a set of ModelNet core nodes, which cooperate to subject the traffic to the bandwidth, congestion constraints, latency, and loss profile of a target network topology. This paper describes and evaluates the ModelNet architecture and its implementation, including novel techniques to balance emulation accuracy against scalability. The current ModelNet prototype is able to accurately subject thousands of instances of a distributed application to Internet-like conditions with gigabits of bisection bandwidth. Experiments with several large-scale distributed services demonstrate the generality and effectiveness of the infrastructur

Hyperbolic Geometry of Complex Networks

We develop a geometric framework to study the structure and function of complex networks. We assume that hyperbolic geometry underlies these networks, and we show that with this assumption, heterogeneous degree distributions and strong clustering in complex networks emerge naturally as simple reflections of the negative curvature and metric property of the underlying hyperbolic geometry. Conversely, we show that if a network has some metric structure, and if the network degree distribution is heterogeneous, then the network has an effective hyperbolic geometry underneath. We then establish a mapping between our geometric framework and statistical mechanics of complex networks. This mapping interprets edges in a network as non-interacting fermions whose energies are hyperbolic distances between nodes, while the auxiliary fields coupled to edges are linear functions of these energies or distances. The geometric network ensemble subsumes the standard configuration model and classical random graphs as two limiting cases with degenerate geometric structures. Finally, we show that targeted transport processes without global topology knowledge, made possible by our geometric framework, are maximally efficient, according to all efficiency measures, in networks with strongest heterogeneity and clustering, and that this efficiency is remarkably robust with respect to even catastrophic disturbances and damages to the network structure

CyberKnife with Tumor Tracking: An Effective Treatment for High-Risk Surgical Patients with Single Peripheral Lung Metastases

Standard treatment for operable patients with single peripheral lung metastases is metastasectomy. We report mature CyberKnife outcomes for high-risk surgical patients with biopsy proven single peripheral lung metastases. Twenty-four patients (median age 73 years) with a mean maximum tumor diameter of 2.5 cm (range, 0.8–4.5 cm) were treated over a 6-year period extending from September 2004 to September 2010 and followed for a minimum of 1 year or until death. A mean dose of 52 Gy (range, 45–60 Gy) was delivered to the prescription isodose line in three fractions over a 3–11 day period (mean, 7 days). At a median follow-up of 20 months, the 2-year Kaplan–Meier local control and overall survival rates were 87 and 50%, respectively. CyberKnife with fiducial tracking is an effective treatment for high-risk surgical patients with single small peripheral lung metastases. Trials comparing CyberKnife with metastasectomy for operable patients are necessary to confirm equivalence

Quantifying randomness in real networks

Represented as graphs, real networks are intricate combinations of order and disorder. Fixing some of the structural properties of network models to their values observed in real networks, many other properties appear as statistical consequences of these fixed observables, plus randomness in other respects. Here we employ the dk-series, a complete set of basic characteristics of the network structure, to study the statistical dependencies between different network properties. We consider six real networks-the Internet, US airport network, human protein interactions, technosocial web of trust, English word network, and an fMRI map of the human brain-and find that many important local and global structural properties of these networks are closely reproduced by dk-random graphs whose degree distributions, degree correlations and clustering are as in the corresponding real network. We discuss important conceptual, methodological, and practical implications of this evaluation of network randomness, and release software to generate dk-random graphs