Structural lubricity under ambient conditions.

Despite its fundamental importance, physical mechanisms that govern friction are poorly understood. While a state of ultra-low friction, termed structural lubricity, is expected for any clean, atomically flat interface consisting of two different materials with incommensurate structures, some associated predictions could only be quantitatively confirmed under ultra-high vacuum (UHV) conditions so far. Here, we report structurally lubric sliding under ambient conditions at mesoscopic (∼4,000-130,000 nm(2)) interfaces formed by gold islands on graphite. Ab initio calculations reveal that the gold-graphite interface is expected to remain largely free from contaminant molecules, leading to structurally lubric sliding. The experiments reported here demonstrate the potential for practical lubrication schemes for micro- and nano-electromechanical systems, which would mainly rely on an atomic-scale structural mismatch between the slider and substrate components, via the utilization of material systems featuring clean, atomically flat interfaces under ambient conditions

Evaluation of radioactive properties and microfaunal evidence in the Bosphorus and the Dardanelles straits and Golden Horn sediments

The aim of this study is to investigate radioactive pollutants from pollution loads transported from the Black Sea to the Aegean Sea by the Turkish Straits System and their effects on microfauna (benthic foraminifer and ostracod) assemblages. In the study, the effects of gross alpha and beta activity on the species number, species diversity, dominant species and species richness of benthic foraminiferal and ostracod assemblages were investigated in 16 bottom sediments taken from different depths in the Golden Horn, Bosphorus and Dardanelles straits. In the studied sediment samples examined 61 genera and 64 species of benthic foraminifera, 23 genera and 26 species of ostracoda were identified. In addition two migratory foraminifera species were observed as Spiroloculina antillarum of Atlantic-Pacific origin and Peneroplis pertusus of Indo-Pacific origin. A relationship between the abundance of microfauna and high gross alpha and beta values was found in the Dardanelles samples, but not in the Bosphorus and Golden Horn samples. In this  study, the highest radioactivity value was observed in the deepest bottom sediment samples. Consequently, the gross alpha and beta values were seen to be close to each other in the Dardanelles Strait and Golden Horn samples, and they had a broad-spectrum in the Bosphorus samples

Histopathologic Evaluation of Nonalcoholic Fatty Liver Disease in Hypothyroidism-Induced Rats

It is speculated that thyroid hormones may be involved in nonalcoholic fatty liver disease (NAFLD) pathogenesis. A literature scan, however, demonstrated conflicting results from studies investigating the relationship between hypothyroidism and NAFLD. Therefore, our study aims to evaluate NAFLD, from the histopathologic perspective, in hypothyroidism-induced rats. Wistar rats were divided into 2 groups: the experimental group consumed water containing methimazole 0.025% (MMI, Sigma, USA) for 12 weeks and the control group consumed tap water. At the end of week 12, serum glucose, ALT, AST, triglyceride, HDL, LDL, TSH, fT4, fT3, visfatin, and insulin assays were performed. Sections were stained with hematoxylin-eosin and “Oil Red-O” for histopathologic examination of the livers. In our study, we detected mild hepatosteatosis in all hypothyroidism-induced rats. There was statistically significant difference with respect to obesity between the two groups (p<0.001). The mean fasting blood glucose was 126.25 ± 23.4 mg/dL in hypothyroidism-induced group and 102.63 ± 15.51 mg/dL in the control group, with a statistically significant difference between the groups (p=0.032). The two groups did not differ statistically significantly with respect to visfatin levels (p>0.05). In conclusion, we found that hypothyroidism-induced rats had mild hepatosteatosis as opposed to the control group histopathologically. Our study indicates that hypothyroidism can cause NAFLD

Efficiently Exploring Architectural Design Spaces via Predictive Modeling

Computer architects rely on cycle-by-cycle simulation to evaluate the impact of design choices and to understand tradeoffs and interactions among design parameters. Although several techniques reduce time per individual simulation, efficiently exploring exponential-size design spaces spanned by several interacting parameters remains an open problem: the sheer number of experiments renders detailed simulation intractable. We attack this via an automated approach for building highly accurate and confident predictive models of design spaces. We collect simulation data incrementally, giving reliable estimates of model error on the full parameter space at each step of the building process. As validation, we perform sensitivity studies on memory system and microprocessor design spaces (conducting over 300K detailed simulations). Our models generally predict IPC with less than 1-2% error, even when trained on as little as 2% of the full design space. Further, our mechanism is orthogonal to techniques that reduce simulation runtimes. SimPoint [23] reduces the number of simulated instructions per experiment by 8-62?. We reduce the total number of simulated instructions by 50-200?. Combining our approach with SimPoint reduces the number of simulated instructions required to complete thorough design-space explorations by 1000-13,000?. Our approach has potential to quantitatively and qualitatively transform computer architecture research, enabling studies heretofore beyond our computational abilities

Çalışan algısına göre hizmet kalitesinin artırılmasında performans değerlemesi ve eğitimin rolü üzerine bir araştırma

ÖZETArtan rekabet koşullarında ayakta kalabilmek için firmalar rakipleri karşısında fark yaratmak zorundadır. Bu nedenle firmalar her geçen gün daha da fazla insan kaynaklarına önem vermekte ve verimliliklerini arttırmaya çalışmaktadır. İnsan kaynakları, firmaların başarı ve başarısızlıklarının temel belirleyicisi konumundadır. İnsan kaynakları yönetiminde performans değerleme çalışmaları günden güne önem kazanmaktadır. Çünkü çalışanlarının performansını arttırmak, firmaların eğildikleri en önemli konuların başında gelmektedir. İnsan kaynakları yönetiminde önem kazanan bir diğer unsur ise eğitimdir. Eğitim, firmaların insan kaynakları yatırımlarında kilit rolü üstlenmektedir. Firmalar, beşeri kaynaklara yatırım yaparak ihtiyaç duydukları çalışanları kendi bünyelerinde yetiştirmektedir. Firmaların, çalışanlar ile ilgili olarak ilgilendikleri performans ve eğitim gibi konuların yanı sıra bir diğer önemli unsur ile hizmet kalitesidir. Bu çalışmada çalışanların düşüncelerine göre eğitimin performansa etkisi araştırılmış, sonrasında ise yine çalışanların düşüncelerine göre performans kalitesinin hizmet kalitesine olan etkisi incelenmiştir. Sonuç olarak çalışanların algılamalarına göre hizmet kalitesinin arttırılmasında, performans değerleme ve eğitimin güçlü sayılabilecek bir etkisinin olduğu görülmüştür. Anahtar Kelimeler: Performans, performans değerleme, eğitim, hizmet, hizmet kalitesiABSTRACTCompanies has to make a difference to survive in the competitive environment in the face of increasing competition. Therefore, companies give importance to human resources, more and more every day and try to increase their productivity. Human resources are the main determinant of the success and failure of firms. Performance evaluation studies in human resources management is gaining importance day by day. Because, increasing the performance of employees is the most important thing for firms. Another factor that has gained importance in the management of human resources is the education. Education plays key role in firms' investments in human resources. Firms are investing to human resources to have employees they need.Service quality is another factor that firms are interested except performance and education. In this study, it has been searched for the effect of education to performance and the effect of performance to service quality according to employee’s opinions. As a result, education and performance has a strong impact on service quality were considered. Key words: Performance, performance assessing, education, service, service qualit

Associative computing with resistive memories

Thesis (Ph. D.)--University of Rochester. Department of Computer Science, 2015.Power dissipation and memory bandwidth are significant performance bottlenecks in virtually all computer systems. Associative computing with ternary content addressable memories (TCAM) holds the potential to address both problems in a wide range of data intensive workloads. Power dissipation is reduced by eliminating instruction processing and data movement overheads present in a purely RAM based system. Bandwidth demand is lowered by processing data directly on the TCAM chip, thereby decreasing -chip traffic. Unfortunately, existing SRAM-based TCAM cells are over 90 larger than a DRAM cell at the same technology node, which limits the capacity of commercially available TCAMs to a few megabytes. This dissertation first examines the integration of gigascale TCAM systems based on resistive memories within a general purpose computing platform. TCAM density is improved by novel, resistive memory cells that exploit phase change and spin-toque transfer magnetoresistive RAM technologies. TCAM chips are organized into a DDR3-compatible DIMM, and are accessed through a software library with zero modifications to the processor or the motherboard. Leveraging associative lookups by the memory circuits and a set of integrated, programmable microcontrollers that execute user-denied kernels on the search results, the proposed TCAM systems achieve average speedups of 4-4.2 and average energy reductions of 6.5-8 as compared to a conventional RAM based system. The dissertation second presents the case for a database processing unit (DPU) that significantly improves the energy efficiency in big data analytics. The DPU augments a general-purpose processor with 1) an STT-MRAM based scratchpad memory that implements a CAM cell with a 2.45 higher density than an SRAM cell, and 2) an enhanced DMA unit that facilitates the transportation of data between the CAM and memory subsystem. By mapping the relational database operators to the CAM circuits, columns of data are processed directly on the CAM chip in a vectorized manner. This eschews streaming the entire data set in and out of the processor pipeline, and significantly reduces the performance and energy overheads caused by the data movement