Subspace design of low-rank estimators for higher-order statistics     

Ivan Bradaric  Athina P. Petropulu  Konstantinos I. Diamantaras 《Journal of The Franklin Institute》2002,339(2):161-187

Higher-order statistics (HOS) are well known for their robustness to additive Gaussian noise and ability to preserve phase. HOS estimates, on the other hand, have been criticized for high complexity and the need for long data in order to maintain small variance. Since rank reduction offers a general principle for reduction of estimator variance and complexity, we consider the problem of designing low-rank estimators for HOS. We propose three methods for choosing the transformation matrix that reduces the mean-square error (MSE) associated with the low-rank HOS estimates. We also demonstrate the advantages of using low-rank third-order moment estimates for blind system estimation. Results indicate that the full rank MSE corresponding to some data length N can be attained by a low-rank estimator corresponding to a length significantly smaller than N.  相似文献   

Graphenes — Aromatic giants     

Ivan Gutman  Boris Furtula 《Resonance》2011,16(12):1238-1245

Recently, extremely large benzenoid hydrocarbons have been synthesized. These compounds resemble graphite in many ways, and have been named graphenes. Because of their nonstandard properties, graphenes have already found numerous applications, especially as special-purpose materials in electronics. In this article we outline the basic chemical facts on graphenes.  相似文献   

A longitudinal study of religious identity and participation during adolescence     

Lopez AB  Huynh VW  Fuligni AJ 《Child development》2011,82(4):1297-1309

To examine the development of religious identity during the teenage years, adolescents (N = 477) from Latin American, Asian, and European backgrounds completed questionnaires in the 10th, 11th, and 12th grades (10th grade age: M = 15.81, SD = 0.36). Results indicated that religious identity remained stable across high school whereas religious participation declined. Even after controlling for ethnic differences in religious affiliation, socioeconomic background, and generational status, adolescents from Latin American and Asian backgrounds reported higher levels of religious identity and adolescents from Latin American backgrounds reported higher rates of religious participation. Within individual adolescents, changes in religious identity were associated with changes in ethnic and family identities, suggesting important linkages in the development of these social identities during adolescence.  相似文献   

The European university landscape: A micro characterization based on evidence from the Aquameth project   总被引：2，自引：0，他引：2  

Cinzia Daraio  Andrea BonaccorsiAldo Geuna  Benedetto LeporiLaurent Bach  Peter BogetoftMargarida F. Cardoso  Elena Castro-MartinezGustavo Crespi  Ignacio Fernandez de LucioHarold Fried  Adela Garcia-AracilAnnamaria Inzelt  Ben JongbloedGerhard Kempkes  Patrick LlerenaMireille Matt  Maria OlivaresCarsten Pohl  Tarmo RatyMaria J. Rosa  Cláudia S. SarricoLéopold Simar  Stig SlipersaeterPedro N. Teixeira  Philippe Vanden Eeckaut 《Research Policy》2011,40(1):148-164

This paper provides a new and systematic characterization of 488 universities, from 11 European countries: Finland, France, Germany, Hungary, Italy, Netherlands, Norway, Portugal, Spain, Switzerland and UK. Using micro indicators built on the integrated Aquameth database, we characterize the European university landscape according to the following dimensions: history/foundation of university, dynamics of growth, specialization pattern, subject mix, funding composition, offer profile and productivity.  相似文献   

A parallel microfluidic channel fixture fabricated using laser ablated plastic laminates for electrochemical and chemiluminescent biodetection of DNA     

Edwards TL  Harper JC  Polsky R  Lopez DM  Wheeler DR  Allen AC  Brozik SM 《Biomicrofluidics》2011,5(4):44115-4411514

Herein is described the fabrication and use of a plastic multilayer 3-channel microfluidic fixture. Multilayer devices were produced by laser machining of plastic polymethylmethacrylate and polyethyleneterapthalate laminates by ablation. The fixture consisted of an array of nine individually addressable gold or gold/ITO working electrodes, and a resistive platinum heating element. Laser machining of both the fluidic pathways in the plastic laminates, and the stencil masks used for thermal evaporation to form electrode regions on the plastic laminates, enabled rapid and inexpensive implementation of design changes. Electrochemiluminescence reactions in the fixture were achieved and monitored through ITO electrodes. Electroaddressable aryl diazonium chemistry was employed to selectively pattern gold electrodes for electrochemical multianalyte DNA detection from double stranded DNA (dsDNA) samples. Electrochemical detection of dsDNA was achieved by melting of dsDNA molecules in solution with the integrated heater, allowing detection of DNA sequences specific to breast and colorectal cancers with a non-specific binding control. Following detection, the array surface could be renewed via high temperature (95 °C) stripping using the integrated heating element. This versatile and simple method for prototyping devices shows potential for further development of highly integrated, multi-functional bioanalytical devices.  相似文献   

Integrated carbon fiber electrodes within hollow polymer microneedles for transdermal electrochemical sensing     

Miller PR  Gittard SD  Edwards TL  Lopez DM  Xiao X  Wheeler DR  Monteiro-Riviere NA  Brozik SM  Polsky R  Narayan RJ 《Biomicrofluidics》2011,5(1):13415

In this study, carbon fiber electrodes were incorporated within a hollow microneedle array, which was fabricated using a digital micromirror device-based stereolithography instrument. Cell proliferation on the acrylate-based polymer used in microneedle fabrication was examined with human dermal fibroblasts and neonatal human epidermal keratinocytes. Studies involving full-thickness cadaveric porcine skin and trypan blue dye demonstrated that the hollow microneedles remained intact after puncturing the outermost layer of cadaveric porcine skin. The carbon fibers underwent chemical modification in order to enable detection of hydrogen peroxide and ascorbic acid; electrochemical measurements were demonstrated using integrated electrode-hollow microneedle devices.  相似文献   

A Good Job Is Hard to Find … Until Students Know What They Do Best          下载免费PDF全文

Shane J. Lopez 《About Campus》2014,19(1):2-6

Why don't more students use the career center? Shane J. Lopez argues that the traditional career center has not kept up with students’ needs. He suggests that they reimagine themselves as places where students identify and nurture their strengths in order to find fulfilling work and create fulfilling lives.  相似文献   

A Behind‐the‐Scenes Guide to School‐Based Research     

Benjamin D. Plummer  Brian M. Galla  Amy S. Finn  Sarah D. Patrick  David Meketon  Julia Leonard  Calvin Goetz  Elizabeth Fernandez‐Vina  Sara Bartolino  Rachel E. White  Angela L. Duckworth 《Mind, Brain, and Education》2014,8(1):15-20

Schools are an important context for both basic and applied scientific research. Unlike the laboratory, however, the physical and social conditions of schools are not under the exclusive control of scientists. In this article, we liken collecting data in schools to putting on a theatrical production. We begin by describing the large cast of characters whose collaborative efforts make school‐based research possible. Next, we address the critics, including the university Institutional Review Board (IRB) and school administrators, whose feedback often improves the final study design. We then turn our attention to set building, stage directions, and rehearsals—key steps in the iterative process of refining study procedures. We end with a discussion of the day of data collection itself and activities that take place after the curtain drops. Throughout, we make recommendations based on our recent experience collecting data at several high schools.  相似文献   

Validation of a laboratory and hospital information system in a medical laboratory accredited according to ISO 15189     

Biljak VR  Ozvald I  Radeljak A  Majdenic K  Lasic B  Siftar Z  Lovrencic MV  Flegar-Mestric Z 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2012,22(1):86-91

Introduction

The aim of the study was to present a protocol for laboratory information system (LIS) and hospital information system (HIS) validation at the Institute of Clinical Chemistry and Laboratory Medicine of the Merkur University Hospital, Zagreb, Croatia.

Materials and methods:

Validity of data traceability was checked by entering all test requests for virtual patient into HIS/LIS and printing corresponding barcoded labels that provided laboratory analyzers with the information on requested tests. The original printouts of the test results from laboratory analyzer(s) were compared with the data obtained from LIS and entered into the provided template. Transfer of data from LIS to HIS was examined by requesting all tests in HIS and creating real data in a finding generated in LIS. Data obtained from LIS and HIS were entered into a corresponding template. The main outcome measure was the accuracy of transfer obtained from laboratory analyzers and results transferred from LIS and HIS expressed as percentage (%).

Results:

The accuracy of data transfer from laboratory analyzers to LIS was 99.5% and of that from LIS to HIS 100%.

Conclusion:

We presented our established validation protocol for laboratory information system and demonstrated that a system meets its intended purpose.  相似文献   

Spatio-temporal analysis of tamoxifen-induced bystander effects in breast cancer cells using microfluidics     

Ivan Rios-Mondragon  Xiang Wang  Hans-Hermann Gerdes 《Biomicrofluidics》2012,6(2):024128-9

The bystander effect in cancer therapy is the inhibition or killing of tumor cells that are adjacent to those directly affected by the agent used for treatment. In the case of chemotherapy, little is known as to how much and by which mechanisms bystander effects contribute to the elimination of tumor cells. This is mainly due to the difficulty to distinguish between targeted and bystander cells since both are exposed to the pharmaceutical compound. We here studied the interaction of tamoxifen-treated human breast cancer MCF-7 cells with their neighboring counterparts by exploiting laminar flow patterning in a microfluidic chip to ensure selective drug delivery. The spatio-temporal evolution of the bystander response in non-targeted cells was analyzed by measuring the mitochondrial membrane potential under conditions of free diffusion. Our data show that the bystander response is detectable as early as 1 hour after drug treatment and reached effective distances of at least 2.8 mm. Furthermore, the bystander effect was merely dependent on diffusible factors rather than cell contact-dependent signaling. Taken together, our study illustrates that this microfluidic approach is a promising tool for screening and optimization of putative chemotherapeutic drugs to maximize the bystander response in cancer therapy.  相似文献