Stephen T. Higgins, PhD; Sarah H. Heil, PhD; Stacey C. Sigmon, PhD; Jennifer W. Tidey, PhD; Diann E. Gaalema, PhD; John R. Hughes, MD; Maxine L. Stitzer, PhD; Hanna Durand, MSN; Janice Y. Bunn, PhD; Jeff S. Priest, PhD; Christopher A. Arger, PhD; Mollie E. Miller, PhD; Cecilia L. Bergeria, MA; Danielle R. Davis, MA; Joanna M. Streck, BA; Derek D. Reed, PhD; Joan M. Skelly, MS; Lauren Tursi, BS
A 4-Gbit/s serial link transceiver is fabricated in a MOSIS 0.5-/spl mu/m HPCMOS process. To achieve the high data rate without speed critical logic on chip, the data are multiplexed when transmitted and immediately demultiplexed when received. This parallelism is achieved by using multiple phases tapped from a PLL using the phase spacing to determine the bit time. Using an 8:1 multiplexer yields 4 Gbits/s, with an on-chip VCO running at 500 MHz. The internal logic runs at 250 MHz. For robust data recovery, the input is sampled at 3/spl times/ the bit rate and uses a digital phase-picking logic to recover the data. The digital phase picking can adjust the sample at the clock rate to allow high tracking bandwidth. With a 3.3-V supply, the chip has a measured bit error rate (BER) of <10/sup -14/.
In 2012, the National Cancer Institute (NCI) engaged the scientific community to provide a vision for cancer epidemiology in the 21st century. Eight overarching thematic recommendations, with proposed corresponding actions for consideration by funding agencies, professional societies, and the research community emerged from the collective intellectual discourse. The themes are (i) extending the reach of epidemiology beyond discovery and etiologic research to include multilevel analysis, intervention evaluation, implementation, and outcomes research; (ii) transforming the practice of epidemiology by moving towards more access and sharing of protocols, data, metadata, and specimens to foster collaboration, to ensure reproducibility and replication, and accelerate translation; (iii) expanding cohort studies to collect exposure, clinical and other information across the life course and examining multiple health-related endpoints; (iv) developing and validating reliable methods and technologies to quantify exposures and outcomes on a massive scale, and to assess concomitantly the role of multiple factors in complex diseases; (v) integrating “big data” science into the practice of epidemiology; (vi) expanding knowledge integration to drive research, policy and practice; (vii) transforming training of 21st century epidemiologists to address interdisciplinary and translational research; and (viii) optimizing the use of resources and infrastructure for epidemiologic studies. These recommendations can transform cancer epidemiology and the field of epidemiology in general, by enhancing transparency, interdisciplinary collaboration, and strategic applications of new technologies. They should lay a strong scientific foundation for accelerated translation of scientific discoveries into individual and population health benefits.
Funding is important for scientists’ work and may contribute to exceptional research outcomes. We analyzed the funding sources reported in the landmark scientific papers of Nobel Prize winners. Between 2000 and 2008, 70 Nobel laureates won recognition in medicine, physics, and chemistry. Sixty five (70%) of the 93 selected papers related to the Nobel‐awarded work reported some funding source including U.S. government sources in 53 (82%), non‐U.S. government sources in 19 (29%), and nongovernment sources in 33 (51%). A substantial portion of this exceptional work was unfunded. We contacted Nobel laureates whose landmark papers reported no funding. Thirteen Nobel laureates responded and offered their insights about the funding process and difficulties inherent in funding. Overall, very diverse sources amounting to a total of 64 different listed sponsors supported Nobel‐related work. A few public institutions, in particular the U.S. National Institutes of Health (with n =26 funded papers) and the National Science Foundation (with n =17 papers), stood out for their successful record for funding exceptional research. However, Nobel‐level work arose even from completely unfunded research, especially when institutions offered a protected environment for dedicated scientists.—Tatsioni, A, Vavva, E., Ioannidis, J.P.A Sources of funding for Nobel Prize‐winning work: public or private? FASEB J. 24, 1335–1339 (2010). www.fasebj.org
Fifty years after Bradford Hill published his extremely influential criteria to offer some guides for separating causation from association, we have accumulated millions of papers and extensive data on observational research that depends on epidemiologic methods and principles. This allows us to re-examine the accumulated empirical evidence for the nine criteria, and to re-approach epidemiology through the lens of exposure-wide approaches. The lecture discusses the evolution of these exposure-wide approaches and tries to use the evidence from meta-epidemiologic assessments to reassess each of the nine criteria and whether they work well as guides for causation. I argue that of the nine criteria, experiment remains important and consistency (replication) is also very essential. Temporality also makes sense, but it is often difficult to document. Of the other six criteria, strength mostly does not work and may even have to be inversed: small and even tiny effects are more plausible than large effects; when large effects are seen, they are mostly transient and almost always represent biases and errors. There is little evidence for specificity in causation in nature. Biological gradient is often unclear how it should it modeled and thus difficult to prove. Coherence remains usually unclear how to operationalize. Finally, plausibility as well as analogy do not work well in most fields of investigation, and their invocation has been mostly detrimental, although exceptions may exist.
Abstract Objective In 2019, Ward et al. proposed a method to adjust BMI calculated from self‐reported weight and height for bias relative to measured data. They did not evaluate the adjusted values relative to measured BMI values for the same individuals. Methods A large data set ( n = 37,439) with both measured and self‐reported weight and height was randomly divided into two groups. The proposed method was used to adjust the BMI values in one group to the measured data from the other group. The adjusted values were then compared with the measured values for the same individuals. Results Before adjustment, 24.9% were incorrectly classified relative to measured BMI categories, including 7.9% in too high a category; after adjustment, 24.3% were incorrectly classified, with 12.8% in too high a category. The variance of the difference was unchanged. The adjustments reduced some errors and introduced new errors. At an individual level, results were unpredictable. Conclusions The suggested method has little effect on misclassification, can introduce new errors, and could magnify errors associated with factors, such as age, race, educational level, or other characteristics. State‐level estimates and projections of obesity prevalence from values adjusted by this method may be incorrect.
With the migration toward low supply voltages in low-power SRAM designs, threshold and supply voltage fluctuations will begin to have larger impacts on the speed and power specifications of SRAM's. We present techniques based on replica circuits which minimize the effect of operating conditions' variability on the speed and power. Replica memory cells and bitlines are used to create a reference signal whose delay tracks that of the bitlines. This signal is used to generate the sense clock with minimal slack time and control wordline pulsewidths to limit bitline swings. We implemented the circuits for two variants of the technique, one using bitline capacitance ratioing in a 1.2-/spl mu/m 8-kbyte SRAM, and the other using cell current ratioing in a 0.35-/spl mu/m 2-kbyte SRAM. Both the RAM's were measured to operate over a wide range of supply voltages, with the latter dissipating 3.6 mW at 150 MHz at 1 V and 5.2 /spl mu/W at 980 kHz at 0.4 V.
Large scale distributed applications such as electronic commerce and online marketplaces combine network access with multiple storage and computational elements. The distributed responsibility for resource control creates new security and privacy issues, which are exacerbated by the complexity of the operating environment. In order to handle policies at multiple locations, the usual tools available (firewalls and compartmented file storage) get to be used in ways that are clumsy and prone to failure. We propose a new approach, virtual private services. Our approach relies on two functional divisions. First, we split policy specification and policy enforcement, providing local autonomy within the constraints of the global security policy. Second, we create virtual security domains, each with its own security policy. Every domain has an associated set of privileges and permissions restricting it to the resources it needs to use and the services it must perform. Virtual private services ensure security and privacy policies are adhered to through coordinated policy enforcement points. We describe our architecture and a prototype implementation, and present a preliminary performance evaluation confirming that our overhead of policy enforcement using is small.
