98 research outputs found

    Wyner-Ziv Coding over Broadcast Channels: Digital Schemes

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    This paper addresses lossy transmission of a common source over a broadcast channel when there is correlated side information at the receivers, with emphasis on the quadratic Gaussian and binary Hamming cases. A digital scheme that combines ideas from the lossless version of the problem, i.e., Slepian-Wolf coding over broadcast channels, and dirty paper coding, is presented and analyzed. This scheme uses layered coding where the common layer information is intended for both receivers and the refinement information is destined only for one receiver. For the quadratic Gaussian case, a quantity characterizing the overall quality of each receiver is identified in terms of channel and side information parameters. It is shown that it is more advantageous to send the refinement information to the receiver with "better" overall quality. In the case where all receivers have the same overall quality, the presented scheme becomes optimal. Unlike its lossless counterpart, however, the problem eludes a complete characterization

    Serum Insulin-Like Growth Factor-1 and Nitric Oxide Levels in Parkinson's Disease

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    The aim of this study was to investigate the role of circulating growth hormone (GH), insulin growth factor-1 (IGF-1), IGF binding protein-3 (IGFBP-3), and nitric oxide (NO) concentrations in the patients suffering from Parkinson's disease (PD). The study groups were consisted of 25 patients with PD and 25 matched healthy subjects as a control. The NO level of patients in PD group (2.3 ± 0.4 μmol/L) was significantly lower than that in the control group (2.8 ± 0.6 μmol/L) (P:.011). Although there were no statistically significant differences in the GH, IGF-1, and IGF BP-3 levels among the two groups, in this preliminary study, we found low NO and mildly elevated IGF-1 levels in the patients with PD. The results may be associated with adaptation or protective mechanisms in the neurodegenerative disease processes such as seen in the PD. Further studies should be carried out to confirm our results

    Serum Levels of Neopterin, Galectin-3, Tissue Necrosis Factor Alpha, and Interleukin-10 During the Interictal and Attack Periods of Patients with Migraine

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    Objective: This study aimed to determine the serum levels of neopterin, galectin-3, tissue necrosis factor alpha, and interleukin-10 (IL-10) during the interictal and attack periods of patients with migraine. It is hoped that the findings will contribute to the literature on the theory of neurogenic inflammation. Materials and Methods: Eighty patients with migraine (40 attacks and 40 interictal periods) and 30 healthy volunteers were included in the study. Blood samples were taken from the people participating in the study, and serum was obtained under the appropriate conditions. The serum levels of all the parameters were determined using a ELISA kit (Coon Koon, Shanghai, China). The difference between the groups was evaluated using appropriate statistical analysis methods. Results: Galectin-3 and neopterin levels were higher during the attack period compared with the interictal period, and IL-10 and galectin-3 levels were higher during the attack period than in the control group. There was no significant difference in any parameter between the control and interictal period groups. There was a correlation between galectin-3 and neopterin levels in all groups (r = 0.598, P < 0.001). Conclusion: The levels of pro-inflammatory molecules, such as galectin-3 and neopterin, were found to be higher in patients with migraine during attacks, which is consistent with the theory of neurogenic inflammation. It is thought that the increase in IL-10 levels during the attack occurs to limit inflammation. Since the tetrahydrobiopterin pathway plays a role in inflammatory and neuropathic pain, it is thought that high neopterin levels during an attack may be associated with migraine headaches

    Kocaeli’de evlerde, ofislerde ve okullarda iç ortam hava kalitesinin belirlenmesi

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    TÜBİTAK ÇAYDAG01.01.2008Bu çalışmada, Kocaeli’de farklı bölgelerde ve farklı mikroçevrelerde (ev, okul, ofis), iç ve dış ortamda yapılan örneklemeler ile aktif ve pasif örnekleme ve ölçüm teknikleri kullanılarak 2 farklı partikül fraksiyonunda (PM2.5 ve PM10) 16 ağır metal (Al, As, Ca, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, S, Si, Ti, V ve Zn), uçucu organik bileşikler (UOB’ler), SO2, NO2 ve O3 konsantrasyonları belirlenmiştir. Ayrıca, iç ortamda ölçülen konsantrasyonlarla maruziyet arasındaki ilişkiyi kurabilmek için, kişisel örnekleyiciler kullanılarak kişisel maruziyet düzeyleri de belirlenmiştir. NO2 için İç Ortam/Dış Ortam konsantrasyon oranlarının evlerde her 2 mevsimde de okullar ve ofislere nazaran yüksek bulunması evlerin iç ortamlarında NO2 kirletici kaynaklarının ofis ve okullara oranla daha baskın olduğu göstermektedir. İç Ortam/Dış Ortam oranlarının 1’in çok altında bulunması O3 ve SO2’in dış ortam kaynaklı bir kirletici olduğunu ve iç ortamlarda önemli bir kaynağının bulunmadığını göstermektedir. PM2.5 fraksiyonundaki toprak kaynaklı elementlerin iç ve dış ortam konsantrasyonlarının yüksek düzeylerde bulunması bu elementlerin iç ortamlara taşınımının yüksek olduğunu göstermektedir. PM2.5 kişisel maruziyet düzeylerinin As, S, V, Cu ve Cr gibi yanma kaynaklı elementler için iç ortam maruziyet düzeylerinden 2–6 kat daha yüksek olması ve bazı mevsimsel farklılıklar bulunmasına rağmen İç Ortam/Dış Ortam oranlarının genellikle 0.3–0.7 aralığında bulunması gözlenen yüksek kişisel maruziyet düzeylerinde dış ortamların etkisini göstermektedir. PM10 partikül fraksiyonunda belirlenen ağır metallerin büyük bir bölümü için İç Ortam/Dış Ortam oranlarının 1’den küçük bulunması dış ortam kirletici kaynaklarının iç ortam kirletici kaynaklarına daha baskın olduğunu göstermektedir. En yüksek UOB kirlilik düzeylerine örneklenen kişilerde rastlanırken bunu iç ortam ve dış ortam UOB kirlilik düzeyleri takip etmiştir. Her 2 mevsimde de toluen ev, ofis ve okullardaki UOB kirlilik düzeylerine en çok katkıda bulunan bileşik olurken onu etilbenzen, m,p-ksilen, stiren, nonan, hegzan, benzen, o-ksilen ve heptan bileşikleri takip etmektedir. Kentsel alanlarda elde edilen toplam UOB konsantrasyonlarının endüstriyel alanlarda elde edilen değerlerle uyum içinde bulunmuştur. Trafiğin belirteci olan bileşikler (BTEX, 1,2,4-trimetilbenzen) kentsel alanlarda yüksek bulunurken petrokimyanın belirteci olan hexane ve heptane bileşikleri endüstrinin yoğun olduğu alanlarda yüksek bulunmuştur. Ayrıca kentsel ve endüstriyel alanlarda elde edilen UOB konsantrasyonlarının sanayii ve trafikten uzak alanlarda elde edilen konsantrasyonlardan yüksek olması trafik ve sanayiinin tesbit edilen UOBlere olan katkısının ne kadar yüksek olduğunu göstermektedir. İç ortam, dış ortam ve kişisel maruziyet kirlilik düzeylerine etki ederek hava kalitesine olumsuz yönde katkıda bulunan kirletici kaynakların belirlenmesi amacıyla Pozitif Matris Faktörizasyonu (PMF) reseptör modelleme tekniği kullanılmıştır. PMF modellemesi, korelasyon analizi, iç ortam/dış ortam oranları, mikroçevre karakteristikleri, anketler ve zaman aktivite çizelgeleri incelenen kirleticilerin en önemli emisyon kaynaklarının endüstri, trafik ve sigara kullanımı olduğunu göstermektedir. İç ortam, dış ortam ve kişisel maruziyet düzeylerinin dünyanın diğer bölgelerinde yapılan çalışmalarda raporlanan düzeyler ile kıyaslanabilir olduğu bulunmuştur. Kişisel maruziyet konsantrasyonları kullanılarak çalışmada incelenen inorganik ve organik kirleticilerden kaynaklanan sağlık riski değerlendirmesi yapılmıştır. Ev, ofis ve okullarda örneklenen kişiler için hesaplanan “Toplam Kanser Riski” ve “Toplam Tehlike İndeksi” değerleri hem ortalama konsantrasyonlar hem de en kötü senaryo göz önüne alınarak incelendiğinde en yüksek risk altında bulunan kişilerin ev hanımları olduğu bunları öğretmenler ve ofis çalışanlarının takip ettiği söylenebilir. Değerlendirme kentsel, endüstriyel, endüstri ve trafikten uzak alanlar için yapıldığında her 3 alanda da yaşayan kişilerin birbirine yakın ve yüksek kanser riski taşıdıkları söylenebilir. Aynı değerlendirme sigara kullanan ve kullanmayan kişiler için yapıldığında sigara kullanan kişilerin kullanmayanlara nazaran yaklaşık %50 daha fazla kanser riski taşıdıkları gözlenmiştir.In this study, indoor and outdoor environment samples were taken from different regions and microenvironments (home, school, office) in Kocaeli. Through active and passive sampling and measurement techniques, 16 heavy metals (Al, As, Ca, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, S, Si, Ti, V and Zn) at 2 different particle fractions (PM2.5 and PM10), volatile organic compounds (VOCs), and SO2, NO2 and O3 concentrations were determined. Moreover, in an effort to establish the relationship between exposure and the indoor concentrations measured, personal samplers were used to determine personal exposure levels. Indoor/outdoor concentration ratios for NO2 were higher in homes than in schools or offices in both summer and winter, which shows that sources of NO2 pollutants in indoor environments of homes are more dominant than those found in offices or schools. The indoor/outdoor ratios were far below 1, indicating that O3 and SO2 are pollutants originating from outdoor environments and that they do not have significant sources in indoor environments. The presence of high levels of indoor and outdoor concentrations of crustal elements at PM2.5 fractions indicates that these elements are transported into indoor environments at high levels. PM2.5 personal exposure levels were 2–6 times higher than indoor levels for combustion-related elements such as As, S, V, Cu and Cr, and although there were some seasonal differences, the indoor/outdoor environment ratios generally ranged between 0.3–0.7 and indicated the effect of outdoor environments on the observed high personal exposure levels. The indoor/outdoor ratios for a major portion of the determined heavy metals at PM10 particle fractions were smaller than 1, showing that outdoor pollutants are more dominant than indoor pollutants. The highest VOC pollution levels were encountered in individuals in the sample, and this was followed by VOC pollution levels in indoor and outdoor environments. In both seasons, toluene levels were the highest pollutants for homes, offices and schools, followed by ethylbenzene, m/p-xylene, styrene, nonane, hexane, benzene, o-xylene and heptane. Total VOC concentrations obtained from urban areas were consistent with values obtained from industrial areas. Components that are indicators of traffic (BTEX, 1,2,4-trimethylbenzene) were measured at high levels in urban areas, while hexane and heptane components, which are indicators of petrochemistry, were recorded at high levels in high- industry areas. Moreover, VOC concentrations obtained from urban and industrial areas were higher than concentrations found in areas far from industry and traffic, which demonstrates the high contribution of traffic and industry to measured VOCs. This study investigated the summer and winter concentrations of selected pollutants and the relationship between indoor and outdoor environments. In order to determine pollutant sources that negatively contribute to air quality by affecting the degree of indoor, outdoor and personal exposures, the Positive Matrix Factorization (PMF) receptor modeling technique was used, which is a multivariate statistical analysis method. PMF, correlation analyses, indoor/outdoor ratios, microenvironment characteristics, responses to questionnaires, and time activity information suggested that industry, traffic and smoking represent the main emission sources of pollutants investigated. Indoor, outdoor and personal exposure concentration values were compared to values measured in different parts of the world, thereby evaluating consistency with the observed pollution level. Based on personal exposure concentrations, an assessment was conducted concerning the health risks associated with the inorganic and organic pollutants investigated in this study. When the calculated values for “Total Health Risk” and “Total Hazard Index” for people sampled in homes, offices and schools were examined by considering both the average concentrations and the worst scenarios, it was revealed that housewives are at the highest risk, followed by teachers and office workers. An examination of urban, industrial and far from urban, industrial and traffic areas revealed that people living in all of these three areas are subjected to high cancer risks, which are at similar levels. When the same evaluation was carried out for smokers and non-smokers, it was observed that smokers have a 50% higher risk of cancer compared to non-smokers

    A comparative ID migraine screener study in ophthalmology, ENT and neurology out-patient clinics

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    Migraine is more likely to be misdiagnosed in patients with comorbid diseases. Not only primary care physicians, but also specialists might misdiagnose it due to the lack of diagnostic criteria awareness. The ID migraine test is a reliable screening instrument that may facilitate and accelerate migraine recognition. This study aimed to compare the prevalence and characteristics of migraine in a large sample of patients admitted to clinics of ophthalmology (OC), ear, nose and throat diseases (ENTC) and neurology (NC), as well as to validate the use of the ID migraine test in OC and ENTC settings. This was a multicentre (11 cites) study of out-patients admitting either to NC, ENTC or OC of the study sites during five consecutive working days within 1 week. From each of the clinics, 100 patients were planned to be recruited. All recruited patients were interviewed and those having a headache complaint received an ID migraine test and were examined for headache diagnosis by a neurologist, blinded to the ID migraine test result. A total of 2625 subjects were recruited. Only 1.3% of OC patients and 5.4% of ENTC patients have been admitted with a primary complaint of headache, whereas the percentage of NC patients suffering from headache was 37.6%. Whereas 138 patients (19.3%) in OC, 154 (17.3%) in ENTC and 347 (34%) in NC were found to be ID migraine test positive, 149 patients (20.8%) in OC, 142 (16%) in ENTC and 338 (33.1%) in NC were diagnosed with migraine. The sensitivity, specificity, and positive and negative predictive ratios of the ID migraine test were found to be similar in all clinics. An important fraction of the patients admitted to NC, as well as to OC and ENTC, for headache and/or other complaints were found out to have migraine by means of a simple screening test. This study validated the ID migraine test as a sensitive and specific tool in OC and ENTC, encouraging its use as a screening instrument.Pfizer-Türkiy

    Innovation and productivity in Turkish manufacturing firms

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    This paper presents a CDM model to investigate the relationship between innovation and productivity for Turkey as a developing country. The results suggest that innovation expenditure increases the probability of innovation, and that innovation affects productivity positively, when other relevant variables are controlled for. As well as the industry-specific concentration ratio, we also investigated the role of firm-specific determinants of innovation such as human capital, exporting, and market share in the innovation – productivity link

    Identification and Lossy Reconstruction in Noisy Databases

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    Bilgi Yayılmaları, İnovasyon ve Verimlilik: Türk İmalat Sanayii İçin Bir CDM Modeli

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    Griliches’nin (1979) bilgi üretim fonksiyonu yaklaşımıyla birlikte, teknolojik bilgi, emek ve sermaye gibi geleneksel üretim faktörlerinin yanında yerini almıştır. Bir iktisadi mal olarak teknolojik bilginin rekabetçi olmaması ve ortaya çıktıktan sonra diğer firmaların kullanımının engellenememesi teknolojik bilgi yayılmalarına yol açmakta; böylece bir firma için başka firmalar tarafından ortaya çıkarılmış bilgi de bir üretim faktörü haline gelmektedir. Bu çalışmada teknolojik bilgi yayılmalarının imalat sanayii firmalarına olan etkisi üç aşamada incelenmektedir: İnovasyon çabasına etki, inovasyona etki ve işgücü verimliliğine etki. TÜİK Yenilik Araştırması veri setinden elde edilen bir örneklem ile, Goya, Vayá, Suriñach (2013) ve Audretsch, Belitski (2020) takip edilerek Crépon, Dugue, Mairesse (1998) tarafından geliştirilen yapısal model kullanılmış ve Türk imalat sanayiinde endüstri içi bilgi yayılmalarının inovasyon sürecine olan etkisi incelenmiştir. Elde edilen bulgulara göre bilgi yayılmaları firmaları daha az inovasyon yatırımı yapmaya yönlendirmekte ancak inovasyon yapma olasılıklarını artırmaktadır. İşgücü verimliliğine doğrudan bir etki gözlemlenememiştir

    TÜRK TAKIM TEZGÂHLARI SANAYİNDE İNOVASYON PERFORMANSINI BELİRLEYİCİ FAKTÖRLERİN ARAŞTIRILMASI

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    Machine tool industry is the essential sector producing investment goods among the industrial sectors and thus has a strategic importance. Innovation in the machine tool industry focuses typically on the technological properties of individual machine tools and their development. In general, the manufacturers are not large scaled. When the technological regime characteristics and innovation patterns of the machine tool sector are considered, the industry has a typical "Specialized Supplier Industry" characteristic in which tacit knowledge accumulated in the interface between the manufacturer and the user is important for the classification of industry of Pavitt. The direction of innovation process in the industry is largely determined by customer requirements. New products are often developed for a specific need of the user and they are launched into the market. Therefore, innovation performances of machine tool producers depend on their new product developing skills. For this reason, this paper focuses on interrelation of product innovation and innovation performance at firm level. To exploring this relation data were collected using a questionnaire from 82 machine tool producers in Turkish machinery industry. The collected data was analyzed with Partial Least Squares Structural Equation Modeling (PLS-SEM) technique. The findings revealed that product innovation has significance positive relationship with firm performance. The findings also revealed that antecedents of product innovation are R&amp;D, investment and external connection capabilities. It has been concluded from this study that improving technological capabilities can increase firms’ innovation performance.Keywords: Innovation, Turkish Machine Tool Industry, PLS-SEM Techniqu
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