86 research outputs found

    Multicast Network Design Game on a Ring

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    In this paper we study quality measures of different solution concepts for the multicast network design game on a ring topology. We recall from the literature a lower bound of 4/3 and prove a matching upper bound for the price of stability, which is the ratio of the social costs of a best Nash equilibrium and of a general optimum. Therefore, we answer an open question posed by Fanelli et al. in [12]. We prove an upper bound of 2 for the ratio of the costs of a potential optimizer and of an optimum, provide a construction of a lower bound, and give a computer-assisted argument that it reaches 22 for any precision. We then turn our attention to players arriving one by one and playing myopically their best response. We provide matching lower and upper bounds of 2 for the myopic sequential price of anarchy (achieved for a worst-case order of the arrival of the players). We then initiate the study of myopic sequential price of stability and for the multicast game on the ring we construct a lower bound of 4/3, and provide an upper bound of 26/19. To the end, we conjecture and argue that the right answer is 4/3.Comment: 12 pages, 4 figure

    An EPTAS for Scheduling on Unrelated Machines of Few Different Types

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    In the classical problem of scheduling on unrelated parallel machines, a set of jobs has to be assigned to a set of machines. The jobs have a processing time depending on the machine and the goal is to minimize the makespan, that is the maximum machine load. It is well known that this problem is NP-hard and does not allow polynomial time approximation algorithms with approximation guarantees smaller than 1.51.5 unless P==NP. We consider the case that there are only a constant number KK of machine types. Two machines have the same type if all jobs have the same processing time for them. This variant of the problem is strongly NP-hard already for K=1K=1. We present an efficient polynomial time approximation scheme (EPTAS) for the problem, that is, for any ε>0\varepsilon > 0 an assignment with makespan of length at most (1+ε)(1+\varepsilon) times the optimum can be found in polynomial time in the input length and the exponent is independent of 1/ε1/\varepsilon. In particular we achieve a running time of 2O(Klog(K)1εlog41ε)+poly(I)2^{\mathcal{O}(K\log(K) \frac{1}{\varepsilon}\log^4 \frac{1}{\varepsilon})}+\mathrm{poly}(|I|), where I|I| denotes the input length. Furthermore, we study three other problem variants and present an EPTAS for each of them: The Santa Claus problem, where the minimum machine load has to be maximized; the case of scheduling on unrelated parallel machines with a constant number of uniform types, where machines of the same type behave like uniformly related machines; and the multidimensional vector scheduling variant of the problem where both the dimension and the number of machine types are constant. For the Santa Claus problem we achieve the same running time. The results are achieved, using mixed integer linear programming and rounding techniques

    Molecular cloning of S1 glycoprotein gene of infectious bronchitis virus (IBV) serotype 793/B in secretory Pichia pastoris vector

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    In vitro protein expression is an important method of obtaining large amounts of viral proteins to investigate their biological properties. The S1 glycoprotein of infectious bronchitis virus, due to its effective immune-dominant role is an appropriate candidate for production of recombinant vaccine against infectious bronchitis disease. In this study, the S1 gene fragment of infectious bronchitis virus strain793/B was amplified using reverse transcriptase-polymerase chain reaction (RT-PCR) and purified. Itwas then cloned into pPICZαA a secretory expression vector of Pichia pastoris. The insertion was proved by PCR analysis and isolation of gene from construct by restriction enzymes and finally, it was sequenced. After the expression of S1 gene in P. pastoris expression system, it was found that it could be used in the production of recombinant vaccines against infectious bronchitis disease. Keywords: Infectious bronchitis, S1 glycoprotein, cloning, Pichia pastori

    The Comparison of the culture operation of Artemia franciscana and parthenogenetic species on the sidelines of Qom Salt Lake

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    Qom Province with an area of 11,238 km^2 , surrounds about 0.68%of the country area and almost situated in the center of the country and enjoys a hot and dry climate . Because of the unique flora and fauna of the region especially the salt pools - hoze- Sultan and salt lakes enjoys a certain ecosystem in the country. Research has done in different parts of Iran and Qom province regarding the Artemia culture in salt lands that showed a great potential in the country and Qom province. The aim of this study that was held in order of Qom fisheries institute and environmental protection organization of that province and scientific leadership of Iranian Artemia Research Center, was the culture of Qom native Artemia and Artemia franciscana ( foreign species ) across Qom salt lake and determining the prevalence of cultured species in this region for this purpose, site selection and climatic and topographic data collection was held at 5 regions of Qom province. This regions were included margins of salt lake, and hoze sultan, shams abad drainage, railway station, and freshwater culture farm at the north east of Qom salt lake. margins of salt lake, and hoze sultan, were suitable for Artemia investment due to suitable climate and vast area, but they had problems in terms of technical facilities and access to areas . Also, the rail way station and plantation industry had dehydration problems. Therefore, after reviewing the field of agricultural water taken along the 45 km of Kashan and Qom Salt Lake were selected for the project because of the salty ecosystem similar to the lake, presence of salt water drainages downstream of the farm , technical facilities and a large area , soil texture and easy access to the area . For this purpose, six pools with 50 square meters near the reservoir pool available were constructed and 70 g native Artemia cysts of Qom and 23/3 g cysts of Artemia franciscana were hatched in Zooks of 10 liters for each pool ea of 50 square meters under standard condition (salinity 35 ppt pH =8, light lux 2000 and temperature 28°C). By calculating the useful volume of water for culture (112 cubic meters) and Hatching efficiency for native Artemia of Qom (40,000) and Artemia franciscana (120,000), the number of 25 nauplii per liter equal to the 2.8 million nauplii were released to each pool with size 4 × 12 m and high slope with area of 50 meter in the floor and 273 meters in the surface . Non- biological and biological studies, including algae and water analysis and population assessments were performed regularly in pools every 2 weeks. the culture period were from July to mid- October, 2009 for a period of 3/5 months. The results of algal study revealed more abundance of Cholestrium, Navicula, Nitzshia algae during culture period (105 days), that Amphora, etraselmis, Cymbella, Senedesmus, Dscillatoria, Gomphonema genera were observed, too. The results of water parameters analysis revealed that they should preserve at salinity 40–50 ppt, pH 8, water hardness 7000- 9000 mg. the results of population assessment showed a larger amounts of female broods of Qom Artemia at days 15,30 and 90 of culture with average number of 120.3, 68.8 and 29.5 per liter, respectively, comparing to Artemia franciscana with average number of 28.8, 17.5 and 7.7 per liter that was significant (p<0.05). The results indicated the greater development and adaptation of native Artemia of Qom at the culture ecosystem of Qom (Kesht va Sanaat Ab Shirin farm at the northeast of Qom salt lake). Harvesting of Artemia biomass of native Qom with the amount of 30 kg/100m^2 showed the production of native Artemia is relatively economic and during culture period (105 days) the mean cyst production for native Qom Artemia and Artemia franciscana were 193 and 123.5 individuals/liter, respectively. It can be concluded that native Qom Artemia enjoys a greater adaptation in growth and development with the arid ecosystem of the region and can be used as a valuable biologic stock in culturing purposes and developing native Artemia strains of the country and investments in construction of Artemia culture pilots in salt areas situated at Qom salt lake

    Molecular barcoding of the Aras reservoir alga Microcystis aeruginosa (Kützing) Kützing 1846 by ITS-2 gene

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    Today, due to population increase and anthropogenic activities together with sewage and agricultural waste water entrance, aquatic ecosystems have been exposed to high pollutions. Phytoplankton is a group of water floating algae that have crucial roles in providing nutrients and oxygen for other organisms, nitrogen and CO_2 fixation. These organisms are considered as primary producers in aquatic ecosystems. They are found in various water habitats all over the world, affected by environmental variables such as pH, light and temperature and used for determination of water pollution degree and quality. Phytoplankton composition and density may be used as a complementary indicator of water trophy state. Phytoplankton communities indicate short and long term variations of aquatic systems. One of the most obvious problems in freshwater ecosystems is algal bloom or over growth of some blue- green algae which can decrease oxygen, and in some cases bring about toxin excretion and fish and human kills. In addition, many of bloom forming cyanobacteria produce secondary metabolites which can create sever poisoning in mammals including human. The genus Microcystis is a key bloom forming cyanobacteria in aquatic ecosystems. Populations of this genus form intense blooms in water bodies that has attracted more attentions in recent years. Various species of this alga have been distributed in stagnant and eutroph freshwater around the world. Microcystis has been defined by genetic criteria such as 16S rRNA molecular sequencing, but its classification in levels lower than genus is unclear and the presence of its classical morphospecies is doubtful. However, this genus creates sever blooms in eutrophic waters all over the world and many species produce toxins. Therefore, identification of its natural diversity in the levels lower than genus has high importance. However, several characteristics of Microcystis morphotypes which are classified a traditional species, actually are present and observed in different regions of the world. At present, they can be considered as morphospecies that belong to one genotype and have similar ecology. These traditional species with definite phenotypic and ecophysiological characteristics cannot be eliminated completely. Their identification is essential for ecological and ecotoxicological studies. Interistic transcribed separator (ITS) gene is a section of genome which is located between 16s rRNA and 23s genes. This gene has more heterogeneity than 16s rRNA; so it is used to identify many genera of cyanobacteria. The Aras reservoir located in the north-west of Iran plays important roles as fisheries, drinking and agricultural water supply and recreational activities in the region. The present thesis was undertaken to: analyze the Microcystis sp. populations by molecular methods such as ITS in Aras Reservoir. Samples for molecular analysis were collected from 10 sampling sites on 18 August 2013. Samples for molecular study of Microcystis were collected from two different depths (surface and 1 m depth) and transferred to laboratory without any treatments. Microscopic images of Microcystis were sent to professor Komárek and was confirmed

    Effects of Artemia parthenogenetica culturing on socioeconomic development of the eastern marginal lands, Qom Salt Lake

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    Saltwater resources with Artemia (Brine shrimp) are the important ecosystems in Semi-arid Areas. That can play an important role in sustaining the economic and social system. Alternatively, will ensure that economic and social issues with of continuity and sustainability of these ecosystems resident. This study carried out "Effects of Artemia parthenogenetica culturing on socio-economic development of the eastern marginal lands, Qom Salt Lake" that was ordered by Qom province general directorate of fisheries during the 2012-2013. According to previous studies, despite the potential of human resources and Social conditions for the development of economic activities, factors such as the low groundwater and drying the salt lake , lack of fresh water in the region, environmental problems , successive droughts, prioritize and rationalize water use in agriculture, Artemia cyst harvest or Artemia culture has made virtually impossible with the current situation and has deprived the tools to make investments for the construction of earthen ponds and exploitation of native Artemia in the eastern margin of the Qom lake . Also, due to the occurrence of the Lake in the national park and privacy protection and Prohibited areas of environmental protection organization, it seems unlikely that this organization grant approval agreement required for any exploitation

    Determination of permitable distance between coldwater culture farms with common water supply in pirdanan river of West Azarbaijan

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    Regarding the increase in world population and decrease in fish stock, there is an urgent need to aquaculture practices. Coldwater fish culture is aiming at production and providing a part of protein needs of the country and a way reaching to self- sufficiency and preserve the water resources. Recently, multi- purpose use of water resources potential and especially the rivers of west Azarbaijan, for example, construction of fish farms at upstream of permanent rivers in order to make optimum use of the resources and the increase in employment has been considered . The waste water of these pools is usually discharged into the rivers. Regarding to increased production per unit area due to water resources and cold water fish culture restrictions to use regional facilities and fish farm construction, it is nessacery to determine limits between 2 farms. In this study with the goal of evaluation of the impacts of trout farm effluents on water quality parameters of Pirdanan River, the factors of water current, temperature, pH, EC, TDS, TSS, DO, BOD_5, NH_3, N-NO_2, N-NO_3, TP P-PO_4 according to standard methods were determined montly during 2014-2015 . Sampling sites were entrance, exit of Maroofi trout farm and the distances of 700, 1400, 2100 and 2800 m after the farm exit. Seasonal sampling of macro invertebrates from mentioned sites was conducted using stone leaching. The family and genus of macro invertebrates were identified using identification keys and abundance of macro invertebrate phylums for each site was determined. The results revealed that the values for water current, EC, TDS, TSS, N-NO_3 were significant. the values of water temperature, BOD5, TDS, TSS, N-NO^3- , N-NO^2-, NH_3, P-PO^4- , NH4+, N-NH3 were increased in site 2 compare to site 1 in all months and gradually in the river and its self- purification were decreased. In this study, 4 phylums, 4 classes, 7orders and 14 families of macroinvertbrates were identified from Pirdanan River. Ephemeroptera had the highest abundance in site 4; while Diptera had the highest abundance in site 2 (exit). Regarding that most of Diptera macro invertebrates were from Chironomidae, so it can be concluded that site 2 was the most pollutant site and sites 5 and 6 were more suitable condition. Therefore, considering the physic- chemical factors and macro inverteberates indices, 2100 m from entrance, (site 5) is recommended compliance with veterinary organization rules and other conditions of aquatic engineering, environmental and water operation standards

    [(18)F] fluoromisonidazole and [(18)F] fluorodeoxyglucose positron emission tomography in response evaluation after chemo-/radiotherapy of non-small-cell lung cancer: a feasibility study

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    BACKGROUND: Experimental and clinical evidence suggest that hypoxia in solid tumours reduces their sensitivity to conventional treatment modalities modulating response to ionizing radiation or chemotherapeutic agents. The aim of the present study was to show the feasibility of determining radiotherapeutically relevant hypoxia and early tumour response by ([(18)F] Fluoromisonidazole (FMISO) and [(18)F]-2-fluoro-2'-deoxyglucose (FDG) PET. METHODS: Eight patients with non-small-cell lung cancer underwent PET scans. Tumour tissue oxygenation was measured with FMISO PET, whereas tumour glucose metabolism was measured with FDG PET. All PET studies were carried out with an ECAT EXACT 922/47(® )scanner with an axial field of view of 16.2 cm. FMISO PET consisted of one static scan of the relevant region, performed 180 min after intravenous administration of the tracer. The acquisition and reconstruction parameters were as follows: 30 min emission scanning and 4 min transmission scanning with 68-Ge/68-Ga rod sources. The patients were treated with chemotherapy, consisting of 2 cycles of gemcitabine (1200 mg/m(2)) and vinorelbine (30 mg/m(2)) followed by concurrent radio- (2.0 Gy/d; total dose 66.0 Gy) and chemotherapy with gemcitabine (300–500 mg/m(2)) every two weeks. FMISO PET and FDG PET were performed in all patients 3 days before and 14 days after finishing chemotherapy. RESULTS: FMISO PET allowed for the qualitative and quantitative definition of hypoxic sub-areas which may correspond to a localization of local recurrences. In addition, changes in FMISO and FDG PET measure the early response to therapy, and in this way, may predict freedom from disease, as well as overall survival. CONCLUSION: These preliminary results warrant validation in larger trials. If confirmed, several novel treatment strategies may be considered, including the early use of PET to evaluate the effectiveness of the selected therapy

    pO polarography, contrast enhanced color duplex sonography (CDS), [18F] fluoromisonidazole and [18F] fluorodeoxyglucose positron emission tomography: validated methods for the evaluation of therapy-relevant tumor oxygenation or only bricks in the puzzle of tumor hypoxia?

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    <p>Abstract</p> <p>Background</p> <p>The present study was conducted to analyze the value of ([<sup>18</sup>F] fluoromisonidazole (FMISO) and [<sup>18</sup>F]-2-fluoro-2'-deoxyglucose (FDG) PET as well as color pixel density (CPD) and tumor perfusion (TP) assessed by color duplex sonography (CDS) for determination of therapeutic relevant hypoxia. As a standard for measuring tissue oxygenation in human tumors, the invasive, computerized polarographic needle electrode system (pO<sub>2 </sub>histography) was used for comparing the different non invasive measurements.</p> <p>Methods</p> <p>Until now a total of 38 Patients with malignancies of the head and neck were examined. Tumor tissue pO<sub>2 </sub>was measured using a pO<sub>2</sub>-histograph. The needle electrode was placed CT-controlled in the tumor without general or local anesthesia. To assess the biological and clinical relevance of oxygenation measurement, the relative frequency of pO<sub>2 </sub>readings, with values ≤ 2.5, ≤ 5.0 and ≤ 10.0 mmHg, as well as mean and median pO<sub>2 </sub>were stated. FMISO PET consisted of one static scan of the relevant region, performed 120 min after intravenous administration. FMISO tumor to muscle ratios (FMISO<sub>T/M</sub>) and tumor to blood ratios (FMISO<sub>T/B</sub>) were calculated. FDG PET of the lymph node metastases was performed 71 ± 17 min after intravenous administration. To visualize as many vessels as possible by CDS, a contrast enhancer (Levovist<sup>®</sup>, Schering Corp., Germany) was administered. Color pixel density (CPD) was defined as the ratio of colored to grey pixels in a region of interest. From CDS signals two parameters were extracted: color hue – defining velocity (v) and color area – defining perfused area (A). Signal intensity as a measure of tissue perfusion (TP) was quantified as follows: TP = v<sub>mean </sub>× A<sub>mean</sub>.</p> <p>Results</p> <p>In order to investigate the degree of linear association, we calculated the Pearson correlation coefficient. Slight (|r| > 0.4) to moderate (|r| > 0.6) correlation was found between the parameters of pO<sub>2 </sub>polarography (pO<sub>2 </sub>readings with values ≤ 2.5, ≤ 5.0 and ≤ 10.0 mmHg, as well as median pO<sub>2</sub>), CPD and FMISO<sub>T/M</sub>. Only a slight correlation between TP and the fraction of pO<sub>2 </sub>values ≤ 10.0 mmHg, median and mean pO<sub>2 </sub>could be detected. After exclusion of four outliers the absolute values of the Pearson correlation coefficients increased clearly. There was no relevant association between mean or maximum FDG uptake and the different polarographic- as well as the CDS parameters.</p> <p>Conclusion</p> <p>CDS and FMISO PET represent different approaches for estimation of therapy relevant tumor hypoxia. Each of these approaches is methodologically limited, making evaluation of clinical potential in prospective studies necessary.</p

    Study of Leishmania pathogenesis in mice : experimental considerations

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    Although leishmaniases are endemic in 98 countries, they are still considered neglected tropical diseases. Leishmaniases are characterized by the emergence of new virulent and asymptomatic strains of Leishmania spp. and, as a consequence, by a very diverse clinical spectrum. To fight more efficiently these parasites, the mechanisms of host defense and of parasite virulence need to be thoroughly investigated. To this aim, animal models are widely used. However, the results obtained with these models are influenced by several experimental parameters, such as the mouse genetic background, parasite genotype, inoculation route/infection site, parasite dose and phlebotome saliva. In this review, we propose an update on their influence in the two main clinical forms of the disease: cutaneous and visceral leishmaniases
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