Finite Sample Analysis of Approximate Message Passing Algorithms

Approximate message passing (AMP) refers to a class of efficient algorithms for statistical estimation in high-dimensional problems such as compressed sensing and low-rank matrix estimation. This paper analyzes the performance of AMP in the regime where the problem dimension is large but finite. For concreteness, we consider the setting of high-dimensional regression, where the goal is to estimate a high-dimensional vector $\beta_0$ from a noisy measurement $y=A \beta_0 + w$. AMP is a low-complexity, scalable algorithm for this problem. Under suitable assumptions on the measurement matrix $A$, AMP has the attractive feature that its performance can be accurately characterized in the large system limit by a simple scalar iteration called state evolution. Previous proofs of the validity of state evolution have all been asymptotic convergence results. In this paper, we derive a concentration inequality for AMP with i.i.d. Gaussian measurement matrices with finite size $n \times N$. The result shows that the probability of deviation from the state evolution prediction falls exponentially in $n$. This provides theoretical support for empirical findings that have demonstrated excellent agreement of AMP performance with state evolution predictions for moderately large dimensions. The concentration inequality also indicates that the number of AMP iterations $t$ can grow no faster than order $\frac{\log n}{\log \log n}$ for the performance to be close to the state evolution predictions with high probability. The analysis can be extended to obtain similar non-asymptotic results for AMP in other settings such as low-rank matrix estimation

Analysis of SPAR 8 single-axis levitation experiment

The melting and resolidification of SPAR 8 payload melting and resolidification of a glass specimen from the in a containerless condition and the retrieval and examination of the specimen from the. The absence of container contact was assured by use of a single-axis acoustic levitation system. However, the sample contacted a wire cage after being held without container contact by the acoustic field for only approximately 87 seconds. At this time, the sample was still molten and, therefore, flowed aroung the wire and continued to adhere to it. An analysis of why the sample did not remain levitated free of container contact is presented. The experiment is described, and experimental observations are discussed and analyzed

The impact of item-writing flaws and item complexity on examination item difficulty and discrimination value

Citation: Rush, B. R., Rankin, D. C., & White, B. J. (2016). The impact of item-writing flaws and item complexity on examination item difficulty and discrimination value. BMC Medical Education, 16(1). doi:10.1186/s12909-016-0773-3Background: Failure to adhere to standard item-writing guidelines may render examination questions easier or more difficult than intended. Item complexity describes the cognitive skill level required to obtain a correct answer. Higher cognitive examination items promote critical thinking and are recommended to prepare students for clinical training. This study evaluated faculty-authored examinations to determine the impact of item-writing flaws and item complexity on the difficulty and discrimination value of examination items used to assess third year veterinary students. Methods: The impact of item-writing flaws and item complexity (cognitive level I-V) on examination item difficulty and discrimination value was evaluated on 1925 examination items prepared by clinical faculty for third year veterinary students. Results: The mean (± SE) percent correct (83.3 % ± 17.5) was consistent with target values in professional education, and the mean discrimination index (0.18 ± 0.17) was slightly lower than recommended (0.20). More than one item-writing flaw was identified in 37.3 % of questions. The most common item-writing flaws were awkward stem structure, implausible distractors, longest response is correct, and responses are series of true-false statements. Higher cognitive skills (complexity level III-IV) were required to correctly answer 38.4 % of examination items. As item complexity increased, item difficulty and discrimination values increased. The probability of writing discriminating, difficult examination items decreased when implausible distractors and all of the above were used, and increased if the distractors were comprised of a series of true/false statements. Items with four distractors were not more difficult or discriminating than items with three distractors. Conclusion: Preparation of examination questions targeting higher cognitive levels will increase the likelihood of constructing discriminating items. Use of implausible distractors to complete a five-option multiple choice question does not strengthen the discrimination value. © 2016 The Author(s)

EC97-277 Minerals and Vitamins For Beef Cows

Introduction Mineral supplementation programs range from elaborate, cafeteria-style delivery systems to simple white salt blocks put out periodically by producers. The reason for this diversity: little applicable research available for producers to evaluate mineral supplement programs. There is a need of information regarding mineral composition and availability from various feedstuffs (i.e. pasture grasses, hays, by-products, etc.) and the possible interactions between minerals in the digestive system. Also lacking is a data base to establish accurate estimates of mineral requirements for beef cattle. Assessing the consequence of mineral deficiencies in the cow, calf or stocker animal is difficult because slightly lowered weight gains in calves, reduced milk production and/or decreased reproduction rates may occur without visible signs of deficiency. At the same time, excess mineral consumption may cause reduced cow and/or calf performance without obvious signs of toxicity. Potential problems can occur due to mineral undernutrition in the cow herd; however, producers need sufficient information to establish a least cost method of correcting mineral undernutrition

Antibody responses to Brugia malayi antigens induced by DNA vaccination

BACKGROUND: DNA vaccination is a convenient means of immunizing animals with recombinant parasite antigens. DNA delivery methods are believed to affect the qualitative nature of immune responses to DNA vaccines in ways that may affect their protective activity. However, relatively few studies have directly compared immune responses to plasmids encoding the same antigens after injection by different routes. Therefore, the purpose of this study was to explore the influence of the route of administration on antibody responses to plasmids encoding antigens from the filarial nematode parasite Brugia malayi. METHODS: Four B. malayi genes and partial genes encoding paramyosin (BM5), heat shock protein (BMHSP-70), intermediate filament (BMIF) and a serodiagnostic antigen (BM14) were inserted in eukaryotic expression vectors (pJW4303 and pCR™3.1). BALB/c mice were immunized with individual recombinant plasmids or with a cocktail of all four plasmids by intramuscular injection (IM) or by gene gun-intradermal inoculation (GG). Antibody responses to recombinant antigens were measured by ELISA. Mean IgG1 to IgG2a antibody ratios were used as an indicator of Th1 or Th2 bias in immune responses induced with particular antigens by IM or GG immunization. The statistical significance of group differences in antibody responses was assessed by the non-parametric Kruskal-Wallis test. RESULTS: Mice produced antibody responses to all four filarial antigens after DNA vaccination by either the IM or GG route. Antibody responses to BM5 paramyosin were strongly biased toward IgG1 with lower levels of IgG2a after GG vaccination, while IM vaccination produced dominant IgG2a antibody responses. Antibody responses were biased toward IgG1 after both IM and GG immunization with BMIF, but antibodies were biased toward IgG2a after IM and GG vaccination with BMHSP-70 and BM14. Animals injected with a mixture of four recombinant plasmid DNAs produced antibodies to all four antigens. CONCLUSIONS: Our results show that monovalent and polyvalent DNA vaccination successfully induced antibody responses to a variety of filarial antigens. However, antibody responses to different antigens varied in magnitude and with respect to isotype bias. The isotype bias of antibody responses following DNA vaccination can be affected by route of administration and by intrinsic characteristics of individual antigens

One Year Sustainability of Risk Factor Change from a 9-Week Workplace Intervention

We examined the effect of a 9-week diet and physical activity intervention provided in the workplace by a group education session where personal dietary and physical activity goals were proposed. Measurements of anthropometry, fasting blood lipids, glucose and insulin, assays for antioxidant activity (AOA) and questionnaires were completed at 0, 3, 6, 9, and 12 weeks in 50 healthy workers (50% male, mean age 46y). Followup measurements in 39 (56% male) were possible at 52 weeks. At week 3 a group dietary and physical activity “motivational seminar” was held. At week 6, half the group were supplied daily kiwifruit for 3 weeks with cross over at week 9 until week 12. Compared to baseline, lipid, glucose, insulin and AOA measurements were improved at 12 and 52 weeks. Body measurements did not change. Group diet and physical activity advice reinforced over 9 weeks is associated with a sustained improvement in cardiovascular risk factors at 52 weeks

Space Use and Movements of Southeastern Breeding Double-Crested Cormorants (\u3ci\u3eNannopterum auritum\u3c/i\u3e) in the United States

Abstract: Seasonal movements of Double-crested Cormorants (Nannopterum auritum) have been studied at breeding and wintering sites in the southeastern United States, but little information exists on the movements of these birds within and from their southern breeding sites in lacustrine systems. Since 2001, cormorants have established nesting colonies on islands in Guntersville Reservoir in Alabama, USA. Following the movements of tagged cormorants using satellite telemetry, we found that the mean home range during the 2017 breeding season (May–August) was 41.76 km2, with a core use area of 6.36 km2. The mean home range used by these birds was largest during the period coinciding with incubation: 9–30 May: (98.86 ± 80.64 km2) compared with the chick-rearing 31 May–4 July: 18.30 ± 22.56 km2), and the post-fledge periods (5 July–15 August: 42.04 ± 30.95 km2). There was no significant difference in the metrics of movement and space use between male and female cormorants assessed in this study. Differences in space used by cormorants breeding in Alabama relative to their northern breeding grounds may be explained by landscape characteristics and availability of prey

Radiation-hard ASICs for optical data transmission in the ATLAS pixel detector

We have developed two radiation-hard ASICs for optical data transmission in the ATLAS pixel detector at the LHC at CERN: a driver chip for a Vertical Cavity Surface Emitting Laser (VCSEL) diode for 80 Mbit/s data transmission from the detector, and a Bi-Phase Mark decoder chip to recover the control data and 40 MHz clock received optically by a PIN diode. We have successfully implemented both ASICs in 0.25 um CMOS technology using enclosed layout transistors and guard rings for increased radiation hardness. We present results from prototype circuits and from irradiation studies with 24 GeV protons up to 57 Mrad (1.9 x 10e15 p/cm2).Comment: 8th Tropical Seminar on Innovative Particle and Radiation Detectors, Siena, Italy (2002

Predicting language change between three and five years and its implications for early identification

BACKGROUND AND OBJECTIVE: Early language delays across the preschool period have important implications for children, parents, and services raising the significance of early identification. Screening tests are an appealing solution but have proved problematic. A combined risk model would seem promising but has yet to be tested. The goal of this study was to examine the factors that predict language change in a nationally representative sample of children between 3 and 5 years when most children are identified as being in need of services. METHODS: By using data from children (n = 13 016) in the Millennium Cohort Study (a national UK birth cohort), linear regression was used to predict 5-year performance from 3-year test performance data coupled with sociodemographic and within-child factors and indicators of parental concern. Patterns of change were identified and logistic regression was used to predict the difference between children for whom profiles change and those for whom they do not. RESULTS: The final model (predicting 32% of the variance) included maternal education, pattern construction, behavior, language concerns, and 3-year vocabulary. Four change patterns were identified: one consistently low (n = 201), one consistently high (n = 12 066), a group that is resilient (n = 572), and one with a declining profile (n = 177). The models accurately predicted 71% of the declining group and 99% of the resilient group. Maternal education (odds ratio: 0.49) and behavior (odds ratio: 0.9) were significant predictors for the former and maternal education (odds ratio: 0.6) and pattern construction (odds ratio: 1.03) the latter. CONCLUSIONS: Early identification of delayed language remains problematic but, once identified, there are key indicators that predict which children are likely to be more or less at risk across time. The implications are discussed in terms of policy and practice. Copyright 2012 by the American Academy of Pediatrics.CIHR130pub279