Beamforming in MISO Systems: Empirical Results and EVM-based Analysis

We present an analytical, simulation, and experimental-based study of beamforming Multiple Input Single Output (MISO) systems. We analyze the performance of beamforming MISO systems taking into account implementation complexity and effects of imperfect channel estimate, delayed feedback, real Radio Frequency (RF) hardware, and imperfect timing synchronization. Our results show that efficient implementation of codebook-based beamforming MISO systems with good performance is feasible in the presence of channel and implementation-induced imperfections. As part of our study we develop a framework for Average Error Vector Magnitude Squared (AEVMS)-based analysis of beamforming MISO systems which facilitates comparison of analytical, simulation, and experimental results on the same scale. In addition, AEVMS allows fair comparison of experimental results obtained from different wireless testbeds. We derive novel expressions for the AEVMS of beamforming MISO systems and show how the AEVMS relates to important system characteristics like the diversity gain, coding gain, and error floor.Comment: Submitted to IEEE Transactions on Wireless Communications, November 200

Method for Instant Saccharomyces cerevisiae Kill of Samples

It is essential when studying the circadian rhythm in cells to be able to effectively stop them in time. In this experiment, we tested what would be the most successful killing agent on Saccharomyces cerevisiae. Six different agents were tested at different concentrations and amounts. After the S. cerevisiae was added to the test tube containing the agent, it was streaked on a plate after 5 and 10 minutes. The plates were incubated and then checked for growth. Ethanol was the most efficient killing agent. After an effective killing agent is determined, it can be used in further experiments measuring Gapdehydrogenase activity using a colorimetric assay to examine the circadian rhythm in Saccharomyces cerevisiae. Gapdehydrogenase results will also be presented

Experiment-driven Characterization of Full-Duplex Wireless Systems

We present an experiment-based characterization of passive suppression and active self-interference cancellation mechanisms in full-duplex wireless communication systems. In particular, we consider passive suppression due to antenna separation at the same node, and active cancellation in analog and/or digital domain. First, we show that the average amount of cancellation increases for active cancellation techniques as the received self-interference power increases. Our characterization of the average cancellation as a function of the self-interference power allows us to show that for a constant signal-to-interference ratio at the receiver antenna (before any active cancellation is applied), the rate of a full-duplex link increases as the self-interference power increases. Second, we show that applying digital cancellation after analog cancellation can sometimes increase the self-interference, and thus digital cancellation is more effective when applied selectively based on measured suppression values. Third, we complete our study of the impact of self-interference cancellation mechanisms by characterizing the probability distribution of the self-interference channel before and after cancellation.Comment: Revised the submission to IEEE Transactions on Wireless Communications, May 2012. Submitted to IEEE Transactions on Wireless Communications, July 201

Bridging distances: Professional development for higher education faculty through technology-facilitated lesson study.

Higher education faculty benefit from participating in communities of practice focused on developing and improving their own instruction. However, collaborators with common interests are not always located at the same physical location. In this article, we share how participation in a technology-facilitated lesson study provided the means for five higher education faculty across the U.S. to engage in professional development and evolve into a virtual community of practice. Through the use of synchronous and asynchronous communication technology, we formulated goals, planned a common lesson, conducted research on our students’ learning, and reflected on our own teaching practice. For this paper, we share how the process of technology-facilitated lesson study provided professional learning for us as individuals

Growing a greater understanding of multiplication through lesson study: Mathematics teacher educators’ professional development

Research cites the need for developing teachers’ mathematical knowledge for teaching (MKT) as well as for developing mathematics teacher educators’ (MTEs) mathematical knowledge for teaching teachers (MKTT). Using the framework of lesson study: formulating goals and researching, planning, implementing and observing, and reflecting (Lewis & Hurd, 2011), a group of MTEs designed and analyzed a lesson on multiplication for prospective elementary teachers. A qualitative analysis of MTE journal reflections and prospective teacher work showed a greater understanding of MTEs’ MKTT related to multiplication after completion of the lesson study. The authors recommend MTEs conduct lesson studies for other mathematics topics to further understand what MKTT MTEs need to develop to best support prospective teachers’ MKT

Sulfur oxidation genes in diverse deep-sea viruses

Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of AAAS for personal use, not for redistribution. The definitive version was published in Science 344 (2014): 757-760, doi:10.1126/science.1252229.Viruses are the most abundant biological entities in the oceans and a pervasive cause of mortality of microorganisms that drive biogeochemical cycles. Although the ecological and evolutionary impacts of viruses on marine phototrophs are well-recognized, little is known about their impact on ubiquitous marine lithotrophs. Here we report 18 genome sequences of double-stranded DNA viruses that putatively infect widespread sulfur-oxidizing bacteria. Fifteen of these viral genomes contain auxiliary metabolic genes for the alpha and gamma subunits of reverse dissimilatory sulfite reductase (rdsr). This enzyme oxidizes elemental sulfur, which is abundant in the hydrothermal plumes studied here. Our findings implicate viruses as a key agent in the sulfur cycle and as a reservoir of genetic diversity for bacterial enzymes that underpin chemosynthesis in the deep oceans.This project is funded in part by the Gordon and Betty Moore Foundation Grant GBMF2609 and National Science Foundation Grant OCE1038006

Baseline characteristics and enrichment results from the SONAR trial

Aim: The SONAR trial uses an enrichment design based on the individual response to the selective endothelin receptor antagonist atrasentan on efficacy (the degree of the individual response in the urinary albumin‐to‐creatinine ratio [UACR]) and safety/tolerability (signs of sodium retention and acute increases in serum creatinine) to assess the effects of this agent on major renal outcomes. The patient population and enrichment results are described here. Methods: Patients with type 2 diabetes with an estimated glomerular filtration rate (eGFR) within 25 to 75 mL/min/1.73 m2 and UACR between 300 and 5000 mg/g were enrolled. After a run‐in period, eligible patients received 0.75 mg/d of atrasentan for 6 weeks. A total of 2648 responder patients in whom UACR decreased by ≥30% compared to baseline were enrolled, as were 1020 non‐responders with a UACR decrease of <30%. Patients who experienced a weight gain of >3 kg and in whom brain natriuretic peptide exceeded ≥300 pg/mL, or who experienced an increase in serum creatinine >20% (0.5 mg/dL), were not randomized. Results: Baseline characteristics were similar for atrasentan responders and non‐responders. Upon entry to the study, median UACR was 802 mg/g in responders and 920 mg/g in non‐responders. After 6 weeks of treatment with atrasentan, the UACR change in responders was −48.8% (95% CI, −49.8% to −47.9%) and in non‐responders was −1.2% (95% CI, −6.4% to 3.9%). Changes in other renal risk markers were similar between responders and non‐responders except for a marginally greater reduction in systolic blood pressure and eGFR in responders. Conclusions: The enrichment period has successfully identified a population with a profound UACR reduction without clinical signs of sodium retention in whom a large atrasentan effect on clinically important renal outcomes is possible. The SONAR trial aims to establish whether atrasentan confers renal protection