Research papers

Wastewater engineering : treatment and reuse

Metcalf, Eddy

1. Wastewater Engineering: An Overview 2. Constituents in Wastewater 3. Analysis and Selection of Wastewater Flowrates and Constituent Loadings 4. Introduction to Process Analysis and Selection 5. Physical Unit Operations 6. Chemical Unit Processes 7. Fundamentals of Biological Treatment 8. Suspended Growth Biological Treatment Processes 9. Attached Growth and Combined Biological Treatment Processes 10. Anaerobic Suspended and Attached Growth Biological Treatment Processes 11. Advanced Wastewater Treatment 12. Disinfection Processes 13. Water Reuse 14. Treatment, Reuse, and Disposal of Solids and Biosolids 15. Issues Related to Treatment-Plant Performance Appendixes A Conversion Factors B Physical Properties of Selected Gases and the Composition of Air C Physical Properties of Water D Solubility of Dissolved Oxygen in Water as a Function of Salinity and Barometric Pressure E MPN Tables and Their Use F Carbonate Equilibrium G Moody Diagrams for the Analysis of Flow in Pipes

The International HapMap Project

Richard A. Gibbs, John W. Belmont, Paul Hardenbol, T. D. Willis, Fuli Yu, Huanming Yang, Lan-Yang Ch'ang, Wei Huang, Bin Liu…

The goal of the International HapMap Project is to determine the common patterns of DNA sequence variation in the human genome and to make this information freely available in the public domain. An international consortium is developing a map of these patterns across the genome by determining the genotypes of one million or more sequence variants, their frequencies and the degree of association between them, in DNA samples from populations with ancestry from parts of Africa, Asia and Europe. The HapMap will allow the discovery of sequence variants that affect common disease, will facilitate development of diagnostic tools, and will enhance our ability to choose targets for therapeutic intervention.

Model selection in ecology and evolution

Jerald B. Johnson, Kristian Shawn Omland

Qualitative content analysis in nursing research: concepts, procedures and measures to achieve trustworthiness

Ulla Hällgren Graneheim, Berit Lundman

Simple model of spiking neurons

Eugene M. Izhikevich

A model is presented that reproduces spiking and bursting behavior of known types of cortical neurons. The model combines the biologically plausibility of Hodgkin-Huxley-type dynamics and the computational efficiency of integrate-and-fire neurons. Using this model, one can simulate tens of thousands of spiking cortical neurons in real time (1 ms resolution) using a desktop PC.

Cytoscape: A Software Environment for Integrated Models of Biomolecular Interaction Networks

Paul Shannon, Andrew Markiel, Owen Ozier, Nitin S. Baliga, Jonathan T. Wang, Daniel Ramage, Nada Amin, Benno Schwikowski, Tr…

Cytoscape is an open source software project for integrating biomolecular interaction networks with high-throughput expression data and other molecular states into a unified conceptual framework. Although applicable to any system of molecular components and interactions, Cytoscape is most powerful when used in conjunction with large databases of protein-protein, protein-DNA, and genetic interactions that are increasingly available for humans and model organisms. Cytoscape's software Core provides basic functionality to layout and query the network; to visually integrate the network with expression profiles, phenotypes, and other molecular states; and to link the network to databases of functional annotations. The Core is extensible through a straightforward plug-in architecture, allowing rapid development of additional computational analyses and features. Several case studies of Cytoscape plug-ins are surveyed, including a search for interaction pathways correlating with changes in gene expression, a study of protein complexes involved in cellular recovery to DNA damage, inference of a combined physical/functional interaction network for Halobacterium, and an interface to detailed stochastic/kinetic gene regulatory models.

Computer and internet use by first year clinical and nursing students in a Nigerian teaching hospital

Grace Ada Ajuwon

BACKGROUND: The internet is an important source of up-to-date medical information. Although several studies in different countries have explored the extent to which health science students use the computer and the internet, few researches are available on this subject in Nigeria. The aim of this study was to assess the uptake of computer and internet by health science students studying in the country. METHODS: One hundred and eighty three first year medical and nursing students of the University College Hospital, Ibadan, Nigeria, completed a-25 item questionnaire during routine Library Orientation Program in the medical library. The EPI-Info software was used for data analysis. RESULTS: The mean ages for medical students and the student nurses were 22 and 24.6 years respectively. Overall, 42.6% of the entire sample could use the computer, 57.4% could not. While more than half (58%) of the medical students are computer literate, majority (75.9%) of the student nurses are not. Slightly more than two thirds (60.7%) of the entire students had ever used the internet, 33. 9% had not. E-mail was the most popular of internet services used by the students (76.4%) and the cyber café was the common place where students had accessed these services. The students' mean scores on a 15-point perceived self-efficacy scale for internet-related tasks was 3.8 for medical and 0.7 for nursing students (p = 0.00). Students who are computer literate had superior mean scores (4.8) than those without (0.6) (p = 0.000). CONCLUSION: First year clinical and nursing students in Ibadan Nigeria have not fully utilised the opportunity that the use of computer and internet offer for medical education. Improved efforts such as inclusion of computer education in medical and nursing curricular and establishment of computer laboratories are required to increase the student's access to computers and internet.

Learning to Teach in Higher Education

Paul Ramsden

This bestselling book is a unique introduction to the practice of university teaching and its underlying theory. This new edition has been fully revised and updated in view of the extensive changes which have taken place in higher education over the last decade and includes new material on the higher education context, evaluation and staff development.The first part of the book provides an outline of the experience of teaching and learning from the student's point of view, out of which grows a set of prinicples for effective teaching in higher education. Part two shows how these ideas can enhance educational standards, looking in particular at four key areas facing every teacher in higher education:* Organising the content of undergraduate courses* Selecting teaching methods* Assessing student learning* Evaluating the effectivenesss of teaching.Case studies of exemplary teaching are used throughout to connect ideas to practice and to illustrate how to ensure better student learning. The final part of the book looks in more detail at appraisal, performance indicators, accountability and educational development and training. The book is essential reading for new and experienced lecturers, particularly those following formal programmes in university teaching, such as courses leading to ILT accreditation.

User Acceptance of Information Technology: Toward A Unified View1

Venkatesh, Michael G. Morris, Gordon B. Davis, Fred D. Davis

Information technology (IT) acceptance research has yielded many competing models, each with different sets of acceptance determinants. In this paper, we (1) review user acceptance literature and discuss eight prominent models, (2) empirically compare the eight models and their extensions, (3) formulate a unified model that integrates elements across the eight models, and (4) empirically validate the unified model. The eight models reviewed are the theory of reasoned action, the technology acceptance model, the motivational model, the theory of planned behavior, a model combining the technology acceptance model and the theory of planned behavior, the model of PC utilization, the innovation diffusion theory, and the social cognitive theory. Using data from four organizations over a six-month period with three points of measurement, the eight models explained between 17 percent and 53 percent of the variance in user intentions to use information technology. Next, a unified model, called the Unified Theory of Acceptance and Use of Technology (UTAUT), was formulated, with four core determinants of intention and usage, and up to four moderators of key relationships. UTAUT was then tested using the original data and found to outperform the eight individual models (adjusted R2 of 69 percent). UTAUT was then confirmed with data from two new organizations with similar results (adjusted R2 of 70 percent). UTAUT thus provides a useful tool for managers needing to assess the likelihood of success for new technology introductions and helps them understand the drivers of acceptance in order to proactively design interventions (including training, marketing, etc.) targeted at populations of users that may be less inclined to adopt and use new systems. The paper also makes several recommendations for future research including developing a deeper understanding of the dynamic influences studied here, refining measurement of the core constructs used in UTAUT, and understanding the organizational outcomes associated with new technology use.

Hierarchical Linear Models: Applications and Data Analysis Methods

Marie Davidian

(2003). Hierarchical Linear Models: Applications and Data Analysis Methods. Journal of the American Statistical Association: Vol. 98, No. 463, pp. 767-768.

Molecular biomimetics: nanotechnology through biology

Mehmet Sarıkaya, Candan Tamerler, Alex K.‐Y. Jen, Klaus Schulten, François Baneyx

MrBayes 3: Bayesian phylogenetic inference under mixed models

Fredrik Ronquist, John P. Huelsenbeck

Abstract Summary: MrBayes 3 performs Bayesian phylogenetic analysis combining information from different data partitions or subsets evolving under different stochastic evolutionary models. This allows the user to analyze heterogeneous data sets consisting of different data types—e.g. morphological, nucleotide, and protein—and to explore a wide variety of structured models mixing partition-unique and shared parameters. The program employs MPI to parallelize Metropolis coupling on Macintosh or UNIX clusters. Availability: http://morphbank.ebc.uu.se/mrbayes Contact: fredrik.ronquist@ebc.uu.se * To whom correspondence should be addressed.

English as a Global Language

David Crystal

David Crystal, world authority on the English language, presents a lively and factual account of the rise of English as a global language and explores the whys and wherefores of the history, current status and future potential of English as the international language of communication. English has been lauded as the most 'successful' language ever, with 1,500 million speakers worldwide; but Crystal avoids taking sides and tells the story in a measured but engaging way, backed by facts and figures. This new edition of his classic book includes new material (on the vocabulary, grammar and pronunciation of New Englishes), footnotes, new tables, and a full bibliography. There are updates throughout. This is a book for anyone of any nationality concerned with English: teachers, students, language professionals, politicians, general readers and anyone with a love of the language.

A Statistical Model for Identifying Proteins by Tandem Mass Spectrometry

Alexey I. Nesvizhskii, Andrew Keller, Eugene Kolker, Ruedi Aebersold

A statistical model is presented for computing probabilities that proteins are present in a sample on the basis of peptides assigned to tandem mass (MS/MS) spectra acquired from a proteolytic digest of the sample. Peptides that correspond to more than a single protein in the sequence database are apportioned among all corresponding proteins, and a minimal protein list sufficient to account for the observed peptide assignments is derived using the expectation-maximization algorithm. Using peptide assignments to spectra generated from a sample of 18 purified proteins, as well as complex H. influenzae and Halobacterium samples, the model is shown to produce probabilities that are accurate and have high power to discriminate correct from incorrect protein identifications. This method allows filtering of large-scale proteomics data sets with predictable sensitivity and false positive identification error rates. Fast, consistent, and transparent, it provides a standard for publishing large-scale protein identification data sets in the literature and for comparing the results obtained from different experiments.

Model Selection and Multimodel Inference: A Practical Information-Theoretic Approach

Fred S. Guthery, Kenneth P. Burnham, David Anderson

Introduction * Information and Likelihood Theory: A Basis for Model Selection and Inference * Basic Use of the Information-Theoretic Approach * Formal Inference From More Than One Model: Multi-Model Inference (MMI) * Monte Carlo Insights and Extended Examples * Statistical Theory and Numerical Results * Summary

The Essential Physics of Medical Imaging

Jerrold T. Bushberg, J. Anthony Seibert, Edwin M. Leidholdt, John M. Boone, Edward Goldschmidt

LT codes

Michael Luby

We introduce LT codes, the first rateless erasure codes that are very efficient as the data length grows.

Polymer Physics

Michael Rubinstein, Ralph H. Colby

Abstract This is a polymer physics textbook for upper level undergraduates and first year graduate students. Any student with a working knowledge of calculus, physics and chemistry should be able to read this book. The essential tools of the polymer physical chemist or engineer are derived in this book without skipping any steps. The book is a self-contained treatise that could also serve as a useful reference for scientists and engineers working with polymers. While no prior knowledge of polymers is assumed, the book goes far beyond introductory polymer texts in the scope of what is covered. The fundamental concepts required to fully understand polymer melts, solutions and gels in terms of both static structure and dynamics are explained in detail. Problems at the end of each Chapter provide the reader with the opportunity to apply what has been learned to practice. The book is divided into four parts. After an introduction in Chapter 1, where the necessary concepts from a first course on polymers are summarized, the conformations of single polymer chains are treated in Part 1. Part 2 deals with the thermodynamics of polymer solutions and melts, including the conformations of chains in those states. Part 3 applies the concepts of Part 2 to the formation and properties of polymer networks. Finally, Part 4 explains the essential aspects of how polymers move in both melt and solution states. In all cases, attention is restricted to concepts that are firmly entrenched in the field.

Geant4—a simulation toolkit

S. Agostinelli, John E. Allison, B. R. Ko, J. Apostolakis, H. M. Araújo, P. Arce, Makoto Asai, D. Axen, Sw. Banerjee, Guy Ba…

The biology of VEGF and its receptors

Napoleone Ferrara, Hans‐Peter Gerber, Jennifer LeCouter

The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure The JNC 7 Report

Aram V. Chobanian

"The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure" provides a new guideline for hypertension prevention and management. The following are the key messages(1) In persons older than 50 years, systolic blood pressure (BP) of more than 140 mm Hg is a much more important cardiovascular disease (CVD) risk factor than diastolic BP; (2) The risk of CVD, beginning at 115/75 mm Hg, doubles with each increment of 20/10 mm Hg; individuals who are normotensive at 55 years of age have a 90% lifetime risk for developing hypertension; (3) Individuals with a systolic BP of 120 to 139 mm Hg or a diastolic BP of 80 to 89 mm Hg should be considered as prehypertensive and require health-promoting lifestyle modifications to prevent CVD; (4) Thiazide-type diuretics should be used in drug treatment for most patients with uncomplicated hypertension, either alone or combined with drugs from other classes. Certain high-risk conditions are compelling indications for the initial use of other antihypertensive drug classes (angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, beta-blockers, calcium channel blockers); (5) Most patients with hypertension will require 2 or more antihypertensive medications to achieve goal BP (<140/90 mm Hg, or <130/80 mm Hg for patients with diabetes or chronic kidney disease); (6) If BP is more than 20/10 mm Hg above goal BP, consideration should be given to initiating therapy with 2 agents, 1 of which usually should be a thiazide-type diuretic; and (7) The most effective therapy prescribed by the most careful clinician will control hypertension only if patients are motivated. Motivation improves when patients have positive experiences with and trust in the clinician. Empathy builds trust and is a potent motivator. Finally, in presenting these guidelines, the committee recognizes that the responsible physician's judgment remains paramount.

Interaction terms in logit and probit models

Chunrong Ai, Edward C. Norton

A survey of industrial model predictive control technology

S. Joe Qin, Thomas A. Badgwell

Latent dirichlet allocation

David M. Blei, Andrew Y. Ng, Michael I. Jordan

We describe latent Dirichlet allocation (LDA), a generative probabilistic model for collections of discrete data such as text corpora. LDA is a three-level hierarchical Bayesian model, in which each item of a collection is modeled as a finite mixture over an underlying set of topics. Each topic is, in turn, modeled as an infinite mixture over an underlying set of topic probabilities. In the context of text modeling, the topic probabilities provide an explicit representation of a document. We present efficient approximate inference techniques based on variational methods and an EM algorithm for empirical Bayes parameter estimation. We report results in document modeling, text classification, and collaborative filtering, comparing to a mixture of unigrams model and the probabilistic LSI model.