Neutral Evolution of Mutational Robustness

We introduce and analyze a general model of a population evolving over a network of selectively neutral genotypes. We show that the population's limit distribution on the neutral network is solely determined by the network topology and given by the principal eigenvector of the network's adjacency matrix. Moreover, the average number of neutral mutant neighbors per individual is given by the matrix spectral radius. This quantifies the extent to which populations evolve mutational robustness: the insensitivity of the phenotype to mutations. Since the average neutrality is independent of evolutionary parameters---such as, mutation rate, population size, and selective advantage---one can infer global statistics of neutral network topology using simple population data available from {\it in vitro} or {\it in vivo} evolution. Populations evolving on neutral networks of RNA secondary structures show excellent agreement with our theoretical predictions.Comment: 7 pages, 3 figure

Gridded circular patch antennas

The performance of circular microstrip patch antennas is presented where the conducting patch and ground plane are constructed from a grid. Improved cross polarization, mode suppression, and band-width are possible, but are accompanied by lower gain and reduced front-to-back ratios. A computer simulation reveals the current structure. The density and shape of the grid pattern are important parameters. Such antennas are can be manufactured within glass laminates. (C) 1999 John Wiley & Sons, Inc

Special Education Parent Perceptions of Involvement and Parent–Educator Relationships During IEP Meetings at Nonpublic Schools

The Individuals with Disabilities Education Improvement Act (IDEIA) requires parents to be involved in all parts of the education decision-making process, including the IEP meeting. Although there is a vast body of research about parents of students receiving special education services and their perspectives of the IEP meeting, little is known about parents’ perspectives of the IEP meeting while students are at a nonpublic school. Understanding the perspectives of parents whose students attend nonpublic schools will allow for more collaboration and more effective IEP for their students attending nonpublic schools. The current study explored parent perspectives of involvement and parent–educator relationships during IEP meetings held at nonpublic schools. A convergent mixed method design combined survey and interview results to build a reliable understanding of parent perspectives at IEP meetings in this environment. A self-administered survey was created and pilot-tested for the study. Forty-one guardians of students who attended a nonpublic school in Orange, San Diego, and Los Angeles Counties volunteered to complete the survey after being contacted through their nonpublic student school, a school district representative, or a parent Facebook group post. A semistructured interview protocol was developed based on the survey and conducted with eight guardians who completed the survey and volunteered to participate in an interview. Descriptive statistics were used to analyze survey data to understand participant perspectives of involvement and parent–educator relationships. Structural, descriptive, and value coding was used to analyze interview data. Between-group vii analysis of variance was used to compare perspectives across demographic groups (e.g., parent race and ethnicity, parent education level, student number of years receiving special education services). Survey and interview results identified high positive ratings for involvement and parent–educator relationships. The participants’ race had a significant impact on parent perspectives of communication during IEP meetings at nonpublic schools; however, due to small group sizes, further research should be conducted to verify the results. No other demographic characteristics analyzed had a significant impact on involvement, communication, or parent– educator relationships

A 3-D differential surface admittance operator for lossy dipole antenna analysis

This letter presents a novel approach to simulate materials with arbitrary properties, in particular good conductors, in a boundary integral equation context. The advocated differential surface admittance operator permits the replacement of the material by the background medium through the introduction of an equivalent surface current density. A formulation based on the eigenfunctions of the volume is constructed and successfully demonstrated through scattering at a conducting cylinder and through the analysis of a lossy dipole antenna

An enhanced differential surface admittance operator for the signal integrity modeling of interconnects

A new, enhanced formulation of the 3-D differential surface admittance operator is presented in this contribution. By employing closed expressions for the sums of the infinite series that arise from discretizing the operator by means of entire domain basis functions, a more efficient and accurate form is obtained. Convergence analysis demonstrates the performance gain. Additionally, the appositeness of the novel operator is studied by analyzing results for various interconnect structures over a broad frequency range and by comparing with other research and commercial solvers

The impact of heat waves and cold spells on mortality rates in the Dutch population.

We conducted the study described in this paper to investigate the impact of ambient temperature on mortality in the Netherlands during 1979-1997, the impact of heat waves and cold spells on mortality in particular, and the possibility of any heat wave- or cold spell-induced forward displacement of mortality. We found a V-like relationship between mortality and temperature, with an optimum temperature value (e.g., average temperature with lowest mortality rate) of 16.5 degrees C for total mortality, cardiovascular mortality, respiratory mortality, and mortality among those [Greater and equal to] 65 year of age. For mortality due to malignant neoplasms and mortality in the youngest age group, the optimum temperatures were 15.5 degrees C and 14.5 degrees C, respectively. For temperatures above the optimum, mortality increased by 0.47, 1.86, 12.82, and 2.72% for malignant neoplasms, cardiovascular disease, respiratory diseases, and total mortality, respectively, for each degree Celsius increase above the optimum in the preceding month. For temperatures below the optimum, mortality increased 0.22, 1.69, 5.15, and 1.37%, respectively, for each degree Celsius decrease below the optimum in the preceding month. Mortality increased significantly during all of the heat waves studied, and the elderly were most effected by extreme heat. The heat waves led to increases in mortality due to all of the selected causes, especially respiratory mortality. Average total excess mortality during the heat waves studied was 12.1%, or 39.8 deaths/day. The average excess mortality during the cold spells was 12.8% or 46.6 deaths/day, which was mostly attributable to the increase in cardiovascular mortality and mortality among the elderly. The results concerning the forward displacement of deaths due to heat waves were not conclusive. We found no cold-induced forward displacement of deaths

EMC-aware analysis and design of a low-cost receiver circuit under injection locking and pulling

In low-cost receiver applications, the preselect filter is often omitted in order to reduce the footprint of the total system. However, the immunity of the receiver can be severely compromised by this approach. This paper focuses on the effects of co-located sources on the local oscillator (LO), specifically injection locking and pulling. To this end, a low-cost radio receiver (RF) front-end is designed for operation in the 2 : 4 5 GHz industrial, scientific and medical (ISM) radio band. In addition to the effects on the oscillator, the consequences on the receiver's performance are evaluated as well. For the first time in literature, this work demonstrates the critical necessity to take the potentially detrimental effects caused by injection locking and pulling into account during Electromagnetic Compatibility (EMC)-aware design

Expansion of the human mitochondrial proteome by intra- and inter-compartmental protein duplication

The human mitochondrial proteome is shown to have expanded due to duplication of protein encoding genes and re-localization of these duplicated proteins

Increasing the coverage of a metapopulation consensus genome by iterative read mapping and assembly

Motivation: Most microbial species can not be cultured in the laboratory. Metagenomic sequencing may still yield a complete genome if the sequenced community is enriched and the sequencing coverage is high. However, the complexity in a natural population may cause the enrichment culture to contain multiple related strains. This diversity can confound existing strict assembly programs and lead to a fragmented assembly, which is unnecessary if we have a related reference genome available that can function as a scaffold. Results: Here, we map short metagenomic sequencing reads from a population of strains to a related reference genome, and compose a genome that captures the consensus of the population's sequences. We show that by iteration of the mapping and assembly procedure, the coverage increases while the similarity with the reference genome decreases. This indicates that the assembly becomes less dependent on the reference genome and approaches the consensus genome of the multi-strain population