bluuebunny/crossref_metadata_2025 huggingface dataset:
The Dielectric Wall Accelerator
Authors: Caporaso George J. , Chen Yu-Jiuan , Sampayan Stephen E.
Published: November 2009

Dielectric wall accelerators, a class of induction accelerators, employ a novel insulating beam tube to impress a longitudinal electric field on a bunch of charged particles. The surface flashover characteristics of this tube may permit the attainment of accelerating gradients on the order of 100 MV/m for accelerating pulses on the order of a nanosecond in duration. A virtual traveling wave of excitation along the tube is produced at any desired speed by controlling the timing of pulse-generating modules that supply a tangential electric field to the tube wall. Because of the ability to control the speed of this virtual wave, the accelerator is capable of handling any charge-to-mass-ratio particle; hence it can be used for electrons, protons and any ion. The accelerator architectures, key technologies and development challenges will be described.
A Man for All Seasons: Robert R. Wilson
Authors: Goldwasser Edwin L.
Published: November 2009

Robert R. Wilson was the brilliant designer, builder and founding director of the Fermi National Accelerator Laboratory with its series of high-energy physics particle accelerators providing collision energies of 200, 400 and 2,000 GeV, the most powerful facilities in their class over a period of 40 years. He undertook the "impossible" and succeeded. With untrammeled courage he challenged the establishment as he bypassed many conventional practices in accelerator design, construction and cost control. With his remarkable talents he addressed a wide range of important aspects of the relationships of art and science, elegance and efficiency and physics and society. In doing so he always found ways for his pursuit of science to support his strong advocacy for human rights, international collaboration and democracy.
Laser Acceleration of Ions for Radiation Therapy
Authors: Tajima Toshiki , Habs Dietrich , Yan Xueqing
Published: November 2009

Ion beam therapy for cancer has proven to be a successful clinical approach, affording as good a cure as surgery and a higher quality of life. However, the ion beam therapy installation is large and expensive, limiting its availability for public benefit. One of the hurdles is to make the accelerator more compact on the basis of conventional technology. Laser acceleration of ions represents a rapidly developing young field. The prevailing acceleration mechanism (known as target normal sheath acceleration, TNSA), however, shows severe limitations in some key elements. We now witness that a new regime of coherent acceleration of ions by laser (CAIL) has been studied to overcome many of these problems and accelerate protons and carbon ions to high energies with higher efficiencies. Emerging scaling laws indicate possible realization of an ion therapy facility with compact, cost-efficient lasers. Furthermore, dense particle bunches may allow the use of much higher collective fields, reducing the size of beam transport and dump systems. Though ultimate realization of a laser-driven medical facility may take many years, the field is developing fast with many conceptual innovations and technical progress.
The Production of Radionuclides for Radiotracers in Nuclear Medicine
Authors: Ruth Thomas J.
Published: November 2009

Medical applications represent the vast majority of the uses for radiotracers. This review addresses how accelerators are employed for the production of high purity radionuclides that are used in basic biomedical research, as well as for clinical medicine both for diagnosing disease and for treatment.
A Simple Proof of Bazzi’s Theorem
Authors: Razborov Alexander
Published: November 2009

Linial and Nisan [1990] asked if any polylog-wise independent distribution fools any function in AC
0
. In a recent remarkable development, Bazzi solved this problem for the case of DNF formulas. The aim of this note is to present a simplified version of his proof.
Directed Planar Reachability Is in Unambiguous Log-Space
Authors: Bourke Chris , Tewari Raghunath , Vinodchandran N. V.
Published: November 2009

We make progress in understanding the complexity of the graph reachability problem in the context of unambiguous logarithmic space computation; a restricted form of nondeterminism. As our main result, we show a new upper bound on the
directed planar reachability problem
by showing that it can be decided in the class unambiguous logarithmic space (UL). We explore the possibility of showing the same upper bound for the general graph reachability problem. We give a simple reduction showing that the reachability problem for directed graphs with thickness two is complete for the class nondeterministic logarithmic space (NL). Hence an extension of our results to directed graphs with thickness two will unconditionally collapse NL to UL.
A Bayesian Approach for Estimating and Replacing Missing Categorical Data
Authors: Li Xiao-Bai
Published: November 2009

We propose a new approach for estimating and replacing missing categorical data. With this approach, the posterior probabilities of a missing attribute value belonging to a certain category are estimated using the simple Bayes method. Two alternative methods for replacing the missing value are proposed: The first replaces the missing value with the value having the estimated maximum probability; the second uses a value that is selected with probability proportional to the estimated posterior distribution. The effectiveness of the proposed approach is evaluated based on some important data quality measures for data warehousing and data mining. The results of the experimental study demonstrate the effectiveness of the proposed approach.
Overview and Framework for Data and Information Quality Research
Authors: Madnick Stuart E. , Wang Richard Y. , Lee Yang W. , Zhu Hongwei
Published: November 2009

Awareness of data and information quality issues has grown rapidly in light of the critical role played by the quality of information in our data-intensive, knowledge-based economy. Research in the past two decades has produced a large body of data quality knowledge and has expanded our ability to solve many data and information quality problems. In this article, we present an overview of the evolution and current landscape of data and information quality research. We introduce a framework to characterize the research along two dimensions:
topics
and
methods
. Representative papers are cited for purposes of illustrating the issues addressed and the methods used. We also identify and discuss challenges to be addressed in future research.
Enriching the spatial reasoning system RCC8
Authors: Alboody Ahed , Inglada Jordi , Sedes Florence
Published: November 2009

One of the necessary basic concepts for the spatial data analysis in GIS is to determine the spatial relations between arbitrary geographical objects. In a two-dimensional space (IR
2
), most existing topological models can distinguish the eight topological relations between two spatial regions A and B. These eight relations are written in the traditional form of the spatial reasoning system RCC8: DC, EC, EQ, PO, TPP, TPPi, NTPP and NTPPi. Because of the complexity of topological relations between geographic regions, it is difficult for these models to describe in detail the topological relations by defining the separation number of lines and points that characterize these relations, and which is very important to enrich the spatial relations of system RCC8. To overcome the insufficiency in existing models, the extension of the Intersection and Difference (ID) model has the ability to describe in detail the topological relations of system RCC8.

In our study, we focus our work on the four relations EC, PO, TPP and TPPi which can be described by the boundary-boundary intersection operator ∂A∩∂B. The main contributions are these four detailed relations which are written and described in the general form EC
mL, nP, kR
, PO
mL, nP, jRI, kR
, TPP
mLT, nPT, kR
and TPPi
mLT, nPT, kR
. Then, we develop definitions for the generalization of these detailed relations. Finally, examples are provided to illustrate the generalization of these new detailed spatial relations.
Specification of a framework for semantic annotation of geospatial data on the web
Authors: Macário Carla Geovana N. , Medeiros Claudia Bauzer
Published: November 2009

The Web is a huge repository of geospatial information (GI), distributed all over the world. Efficient retrieval of this information is a key factor in planning and decision-making in a variety of domains. However, the proposed standards and specifications for data annotation and exchanging enable only syntactic interoperability. Semantic heterogeneity still presents challenges for GI retrieval. One possible approach to tackle these problems is to elicit knowledge by means of semantic annotations, based on multiple ontologies. This work describes a framework to support management of semantic annotations for digital content on the Web, for agricultural planning and monitoring. This will help end-users (agronomers, farmers, Earth scientists) to work cooperatively in developing integrated practices for land management. Content to be annotated in this context includes, for instance, satellite images, sensor data temporal series (e.g., from ground sensors or weather stations), and all kinds of textual data files.
Mapping of large magnitude discontinuous sea ice motion
Authors: Thomas M. , Kambhamettu C. , Geiger C. A.
Published: November 2009

In this work, we attempt to extend the body of knowledge on sea ice motion tracking in two specific directions. The first direction is the development of a computationally efficient, high resolution motion tracking system with a resolution of 400m, which is an order of magnitude greater than the currently available standard data products (3--5km). Validation of this method using GPS measurements shows an average error that is less than 0.06cm/s. The second direction is the development of objective analysis technique to handle motion at close proximity to discontinuities. The goal of this second direction is to identify and track discontinuous features such as cracks, leads, ridges and other material damage zones. These developments allow motion to be estimated at a high resolution in a robust manner (validated against various noise models). With the observed changes in global climate, sparked by variations in the sea ice thickness and extent, our long term goal is to use this system to merge the "temporally rich" GPS measurements with the "spatially rich" measurements from satellite images.
pRPL
Authors: Guan Qingfeng
Published: November 2009

pRPL is an open-source general-purpose programming library developed by the author to parallelize almost any raster-processing algorithm with any arbitrary neighborhood configuration, and support any data type. This paper introduces the advanced features of pRPL, compares it with other similar programming libraries, and demonstrates the performance of a parallel geographic Cellular Automata (CA) model developed using pRPL with real-world datasets. In conclusion, pRPL effectively reduces the development complexity of parallel programming, and efficiently reduces the computing time.
Privacy for real-time location-based services
Authors: Kulik Lars
Published: November 2009

Location-Based Services (LBSs) are developing at an amazing pace. Whereas the first generation of LBSs required manual user input of location information via simple web-based interfaces, current GPS-enabled devices such as smartphones or in-car navigation systems can automatically initiate and negotiate LBSs based on their current position. The latest generation of LBSs combines high position accuracy with real-time position updates, which enables numerous applications including asset tracking, location-based advertising, location-sensitive billing, and street-level routing and positioning.
Foot-driven computing
Authors: Stajano Frank
Published: November 2009

Ubiquitous computing has been a fashionable research theme for the past twenty years, so much so that many research groups have felt the urge to give it a different name (pervasive computing, calm computing, ambient intelligence etc etc) in order to claim that they were doing something new or at least slightly different from everyone else. One of these many alternate names has been "context-aware computing", to suggest systems and devices that would sense the "context" of a situation and behave accordingly: for example, a mobile phone might sense that its owner is "in a meeting" and automatically switch from ringtone to vibration mode.
Improved Separations between Nondeterministic and Randomized Multiparty Communication
Authors: David Matei , Pitassi Toniann , Viola Emanuele
Published: November 2009

We exhibit an explicit function
f
: {0, 1}
n
→{0, 1} that can be computed by a nondeterministic number-on-forehead protocol communicating
O
(log
n
) bits, but that requires
n
Ω(1)
bits of communication for randomized number-on-forehead protocols with
k
 = 
δ
·log
n
players, for any fixed
δ
 < 1. Recent breakthrough results for the Set-Disjointness function [Lee and Shraibman 2008; Chattopadhyay and Ada 2008] based on the work of Sherstov [2009; 2008a] imply such a separation but only when the number of players is
k
 < loglog
n
.

We also show that for any
k
 = 
A
·loglog
n
the above function
f
is computable by a small circuit whose depth is constant whenever
A
is a (possibly large) constant. Recent results again give such functions but only when the number of players is
k
 < loglog
n
.
Hardness of Solving Sparse Overdetermined Linear Systems
Authors: Guruswami Venkatesan , Raghavendra Prasad
Published: November 2009

A classic result due to Håstad established that for every constant
ε
 > 0, given an overdetermined system of linear equations over a finite field F
q
where each equation depends on exactly 3 variables and at least a fraction (1 − 
ε
) of the equations can be satisfied, it is NP-hard to satisfy even a fraction (1/
q
 + ε) of the equations.

In this work, we prove the analog of Håstad’s result for equations over the integers (as well as the reals). Formally, we prove that for every
ε
,
δ
 > 0, given a system of linear equations with integer coefficients where each equation is on 3 variables, it is NP-hard to distinguish between the following two cases: (i) there is an assignment of integer values to the variables that satisfies at least a fraction (1 − 
ε
) of the equations, and (ii) no assignment even of real values to the variables satisfies more than a fraction
δ
of the equations.
Higher reliability redundant disk arrays
Authors: Thomasian Alexander , Blaum Mario
Published: November 2009

Parity is a popular form of data protection in
redundant arrays of inexpensive/independent disks (RAID)
. RAID5 dedicates one out of
N
disks to parity to mask single disk failures, that is, the contents of a block on a failed disk can be reconstructed by exclusive-ORing the corresponding blocks on surviving disks. RAID5 can mask a single disk failure, and it is vulnerable to data loss if a second disk failure occurs. The RAID5 rebuild process systematically reconstructs the contents of a failed disk on a spare disk, returning the system to its original state, but the rebuild process may be unsuccessful due to unreadable sectors. This has led to
two disk failure tolerant arrays (2DFTs)
, such as RAID6 based on Reed-Solomon (RS) codes. EVENODD, RDP (Row-Diagonal-Parity), the X-code, and RM2 (Row-Matrix) are 2DFTs with parity coding. RM2 incurs a higher level of redundancy than two disks, while the X-code is limited to a prime number of disks. RDP is optimal with respect to the number of XOR operations at the encoding, but not for short write operations. For small symbol sizes EVENODD and RDP have the same disk access pattern as RAID6, while RM2 and the X-code incur a high recovery cost with two failed disks. We describe variations to RAID5 and RAID6 organizations, including clustered RAID, different methods to update parities, rebuild processing, disk scrubbing to eliminate sector errors, and the
intra-disk redundancy (IDR)
method to deal with sector errors. We summarize the results of recent studies of failures in hard disk drives. We describe Markov chain reliability models to estimate RAID
mean time to data loss (MTTDL)
taking into account sector errors and the effect of disk scrubbing. Numerical results show that RAID5 plus IDR attains the same MTTDL level as RAID6, while incurring a lower performance penalty. We conclude with a survey of analytic and simulation studies of RAID performance and tools and benchmarks for RAID performance evaluation.
Dynamic load balancing for I/O-intensive applications on clusters
Authors: Qin Xiao , Jiang Hong , Manzanares Adam , Ruan Xiaojun , Yin Shu
Published: November 2009

Load balancing for clusters has been investigated extensively, mainly focusing on the effective usage of global CPU and memory resources. However, previous CPU- or memory-centric load balancing schemes suffer significant performance drop under I/O-intensive workloads due to the imbalance of I/O load. To solve this problem, we propose two simple yet effective I/O-aware load-balancing schemes for two types of clusters: (1) homogeneous clusters where nodes are identical and (2) heterogeneous clusters, which are comprised of a variety of nodes with different performance characteristics in computing power, memory capacity, and disk speed. In addition to assigning I/O-intensive sequential and parallel jobs to nodes with light I/O loads, the proposed schemes judiciously take into account both CPU and memory load sharing in the system. Therefore, our schemes are able to maintain high performance for a wide spectrum of workloads. We develop analytic models to study mean slowdowns, task arrival, and transfer processes in system levels. Using a set of real I/O-intensive parallel applications and synthetic parallel jobs with various I/O characteristics, we show that our proposed schemes consistently improve the performance over existing non-I/O-aware load-balancing schemes, including CPU- and Memory-aware schemes and a PBS-like batch scheduler for parallel and sequential jobs, for a diverse set of workload conditions. Importantly, this performance improvement becomes much more pronounced when the applications are I/O-intensive. For example, the proposed approaches deliver 23.6--88.0 % performance improvements for I/O-intensive applications such as LU decomposition, Sparse Cholesky, Titan, Parallel text searching, and Data Mining. When I/O load is low or well balanced, the proposed schemes are capable of maintaining the same level of performance as the existing non-I/O-aware schemes.
Design space exploration and data memory architecture design for a hybrid nano/CMOS dynamically reconfigurable architecture
Authors: Zhang Wei , Jha Niraj K. , Shang Li
Published: November 2009

In recent years, research on nanotechnology has advanced rapidly. Novel nanodevices have been developed, such as those based on carbon nanotubes, nanowires, etc. Using these emerging nanodevices, diverse nanoarchitectures have been proposed. Among them, hybrid nano/CMOS reconfigurable architectures have attracted attention because of their advantages in performance, integration density, and fault tolerance. Recently, a high-performance hybrid nano/CMOS reconfigurable architecture, called NATURE, was presented. NATURE comprises CMOS reconfigurable logic and interconnect fabric, and CMOS-fabrication-compatible nanomemory. High-density, fast nano RAMs are distributed in NATURE as on-chip storage to store multiple reconfiguration copies for each reconfigurable element. It enables cycle-by-cycle runtime reconfiguration and a highly efficient computational model, called temporal logic folding. Through logic folding, NATURE provides more than an order of magnitude improvement in logic density and area-delay product, and significant design flexibility in performing area-delay trade-offs, at the same technology node. Moreover, NATURE can be fabricated using mainstream photolithography fabrication techniques. Hence, it offers a currently commercially viable reconfigurable architecture with high performance, superior logic density, and outstanding design flexibility, which is very attractive for deployment in cost-conscious embedded systems.

In order to fully explore the potential of NATURE and further improve its performance, in this article, a thorough design space exploration is conducted to optimize its architecture. Investigations in terms of different logic element architectures, interconnect designs, and various technologies for nano RAMs are presented. Nano RAMs can not only be used as storage for configuration bits, but the high density of nano RAMs also makes them excellent candidates for large-capacity on-chip data storage in NATURE. Many logic- and memory-intensive applications, such as video and image processing, require large storage of temporal results. To enhance the capability of NATURE for implementing such applications, we investigate the design of nano data memory structures in NATURE and explore the impact of memory density. Experimental results demonstrate significant throughput improvements due to area saving from logic folding and parallel data processing.
Building a framework for the probability ranking principle by a family of expected weighted rank
Authors: Dang Edward Kai Fung , Wu Ho Chung , Luk Robert Wing Pong , Wong Kam Fai
Published: November 2009

A new principles framework is presented for retrieval evaluation of ranked outputs. It applies decision theory to model relevance decision preferences and shows that the Probability Ranking Principle (PRP) specifies optimal ranking. It has two new components, namely a probabilistic evaluation model and a general measure of retrieval effectiveness. Its probabilities may be interpreted as subjective or objective ones. Its performance measure is the expected weighted rank which is the weighted average rank of a retrieval list. Starting from this measure, the expected forward rank and some existing retrieval effectiveness measures (e.g., top
n
precision and discounted cumulative gain) are instantiated using suitable weighting schemes after making certain assumptions. The significance of these instantiations is that the ranking prescribed by PRP is shown to be optimal simultaneously for all these existing performance measures. In addition, the optimal expected weighted rank may be used to normalize the expected weighted rank of retrieval systems for (summary) performance comparison (across different topics) between systems. The framework also extends PRP and our evaluation model to handle graded relevance, thereby generalizing the discussed, existing measures (e.g., top
n
precision) and probabilistic retrieval models for graded relevance.
MUADDIB
Authors: Rosaci Domenico , Sarné Giuseppe M. L. , Garruzzo Salvatore
Published: November 2009

Web recommender systems are Web applications capable of generating useful suggestions for visitors of Internet sites. However, in the case of large user communities and in presence of a high number of Web sites, these tasks are computationally onerous, even more if the client software runs on devices with limited resources. Moreover, the quality of the recommendations strictly depends on how the recommendation algorithm takes into account the currently used device. Some approaches proposed in the literature provide multidimensional recommendations considering, besides items and users, also the exploited device. However, these systems do not efficiently perform, since they assign to either the client or the server the arduous cost of computing recommendations. In this article, we argue that a fully distributed organization is a suitable solution to improve the efficiency of multidimensional recommender systems. In order to address these issues, we propose a novel distributed architecture, called MUADDIB, where each user's device is provided with a
device assistant
that autonomously retrieves information about the user's behavior. Moreover, a single
profiler
, associated with the user, periodically collects information coming from the different user's device assistants to construct a global user's profile. In order to generate recommendations, a
recommender
precomputes data provided by the profilers. This way, the site manager has only the task of suitably presenting the content of the site, while the computation of the recommendations is assigned to the other distributed components. Some experiments conducted on real data and using some well-known metrics show that the system works more effectively and efficiently than other device-based distributed recommenders.
Machine learning in disruption-tolerant MANETs
Authors: Xu Bo , Wolfson Ouri , Naiman Channah
Published: November 2009

In this article we study the data dissemination problem in which data items are flooded to all the moving objects in a mobile ad hoc network by peer-to-peer transfer. We show that if memory and bandwidth are bounded at moving objects, then the problem of determining whether a set of data items can be disseminated to all the moving objects is NP-complete. For a heuristic solution we postulate that a moving object should save and transmit the data items that are most likely to be new (i.e., previously unknown) to future encountered moving objects. We propose a method to be used by each moving object to prioritize data items based on their probabilities of being new to future receivers. The method employs a machine learning system for estimation of the novelty probability and the machine learning system is progressively trained by received data items. Through simulations based on real mobility traces, we show the superiority of the method against some natural alternatives.
Using OpenStreetMap to deliver location-based environmental information in Ireland
Authors: Ciepluch Blazej , Mooney Peter , Jacob Ricky , Winstanley Adam C.
Published: November 2009

This paper outlines research work-in-progress on delivery of location-based services for environmental information in Ireland. A prototype web map service (WMS) is developed to deliver map-based environmental information using a specially customised version of the OpenStreetMap database. This WMS must deliver a location-based information package to the user: maps of the area that the user is viewing, key state-of-the-environment indicator information for that geographical area, and links to where the actual data and further environmental information can be obtained. This information package must be presented in a way that best matches the environmental preferences of the user. These preferences are derived from a set of 'user profiles' of potential users of the WMS. Software tools developed during this work to derive geospatial products from the OpenStreetMap database are described and some of our observations of working with OpenStreetMap are discussed. The paper closes with the likely directions for the continuation of this research.
Properdin: Emerging Roles of a Pattern-Recognition Molecule
Authors: Kemper Claudia , Atkinson John P. , Hourcade Dennis E.
Published: November 2009

Complement is an innate immune system that is a first line of defense against pathogens and facilitates elimination of apoptotic and injured cells. During complement activation, the complement convertases are assembled on target surfaces and initiate their proteolytic activities, a process that marks targets for phagocytosis and/or lysis. The complement alternative activation pathway has been implicated in a number of autoimmune conditions including arthritis and age-related macular degeneration. Properdin, a plasma component that is also released by activated neutrophils, is critical in the stabilization of alternative pathway convertases. Recently, it has been shown that properdin is also a pattern-recognition molecule that binds to certain microbial surfaces, apoptotic cells, and necrotic cells. Once bound to a surface, properdin can direct convertase formation and target uptake. New studies are now focusing on a role for properdin in inflammatory and autoimmune diseases. This review examines the new properdin findings and their implications.
Changing Ecology of Tropical Forests: Evidence and Drivers
Authors: Lewis Simon L. , Lloyd Jon , Sitch Stephen , Mitchard Edward T.A. , Laurance William F.
Published: November 2009

Global environmental changes may be altering the ecology of tropical forests. Long-term monitoring plots have provided much of the evidence for large-scale, directional changes in tropical forests, but the results have been controversial. Here we review evidence from six complementary approaches to understanding possible changes: plant physiology experiments, long-term monitoring plots, ecosystem flux techniques, atmospheric measurements, Earth observations, and global-scale vegetation models. Evidence from four of these approaches suggests that large-scale, directional changes are occurring in the ecology of tropical forests, with the other two approaches providing inconclusive results. Collectively, the evidence indicates that both gross and net primary productivity has likely increased over recent decades, as have tree growth, recruitment, and mortality rates, and forest biomass. These results suggest a profound reorganization of tropical forest ecosystems. We evaluate the most likely drivers of the suite of changes, and suggest increasing resource availability, potentially from rising atmospheric CO2 concentrations, is the most likely cause.
Electronic Properties of Nonideal Nanotube Materials: Helical Symmetry Breaking in DNA Hybrids
Authors: Rotkin Slava V.
Published: November 2009

Helical wrapping of single-strand DNA around single-wall nanotubes (SWNTs) results in the symmetry breaking and modification of the nanotube band structure. Empirical tight-binding theory was employed to investigate this symmetry breaking and modulation of the electronic and optical properties of a SWNT in the field of an ionized DNA. The model allows the computation of the polarization component of the hybrid's energy of cohesion, with a typical value of 0.5 eV per DNA base. A screening parameter that quantifies the response of the SWNT electrons to the DNA perturbation was obtained. SWNT symmetry breaking shows up in the optical absorption for light polarized across the SWNT axis. In addition, circular dichroism is predicted for DNA-SWNT hybrids, even when the nanotube itself is achiral. These optical effects may be used for experimental determination of the DNA wrapping.
A Long Polycentric Journey
Authors: Ostrom Elinor
Published: November 2009

In this account, I discuss my own personal journey and the efforts of many of us associated with the Workshop in Political Theory and Policy Analysis at Indiana University to develop better analyses of how institutions affect behavior and outcomes in diverse settings. First, I reflect on my experience as a young student and in my early career, primarily to encourage those who face obstacles. Then, I discuss our institutional analysis and our research on urban governance and common-pool resources, which helped me to develop more general frameworks for the analysis of complex systems over time. The frameworks have enabled us to dig into and analyze system structure, behavior, and outcomes to make and test coherent predictions and build better theory. Last, I share some ideas concerning future scholarly directions.
Bridging the Qualitative-Quantitative Divide: Best Practices in the Development of Historically Oriented Replication Databases
Authors: Lieberman Evan S.
Published: November 2009

The proliferation of historically oriented replication data has provided great opportunities for political scientists to develop and to test theories relevant to a range of macrohistorical phenomena. But what is the quality of such data? Are the codings or quantitative mappings of historical events, processes, and unit characteristics based on sufficiently solid foundations equivalent to those found in detailed case studies? This article evaluates a set of the most transparently disseminated replication datasets across a variety of research domains from the perspective of best-practice qualitative-historical research. It identifies a wide range of practices, highlighting both fundamental and innovative standards that might be adopted in future research.
Hand-held model of a sarcomere to illustrate the sliding filament mechanism in muscle contraction
Authors: Jittivadhna Karnyupha , Ruenwongsa Pintip , Panijpan Bhinyo
Published: November 2009

From our teaching of the contractile unit of the striated muscle, we have found limitations in using textbook illustrations of sarcomere structure and its related dynamic molecular physiological details. A hand-held model of a striated muscle sarcomere made from common items has thus been made by us to enhance students' understanding of the sliding filament mechanism as well as their appreciation of the spatial arrangements of the thick and thin filaments. The model proves to be quite efficacious in dispelling some alternative conceptions held by students exposed previously only to two-dimensional textbook illustrations and computer graphic displays. More importantly, after being taught by this hand-held device, electronmicrographic features of the A and I bands, H zone, and Z disk can be easily correlated by the students to the positions of the thick and thin elements relatively sliding past one another. The transverse expansion of the sarcomere and the constancy of its volume upon contraction are also demonstrable by the model.
Evaluation of the Virtual Physiology of Exercise Laboratory program
Authors: Dobson John L.
Published: November 2009

The Virtual Physiology of Exercise Laboratory (VPEL) program was created to simulate the test design, data collection, and analysis phases of selected exercise physiology laboratories. The VPEL program consists of four modules: 1) cardiovascular, 2) maximal O2 consumption (V̇o2max), 3) lactate and ventilatory thresholds, and 4) respiratory exchange ratio. The purpose of this investigation was to compare student learning from the VPEL program with that from traditional “hands-on” exercise physiology laboratory activities. Student participants from the spring 2009 Integrated Fitness Programming course were randomly assigned to either experimental group 1 or group 2. Group 1 completed a hands-on version of a typical V̇o2max laboratory activity, whereas group 2 completed the VPEL V̇o2max module. Both groups then completed the same assessment to evaluate their understanding of V̇o2max laboratory concepts. Group 1 then completed the VPEL lactate and ventilatory threshold module, whereas group 2 completed a hands-on version of that same activity. Both groups then completed the same assessment to evaluate their understanding of lactate and ventilatory threshold laboratory concepts. Mean V̇o2max assessment scores were 86.39 ± 4.13 and 85.64 ± 6.72 and mean lactate and ventilatory threshold assessment scores were 85.50 ± 8.05 and 86.15 ± 6.45 for groups 1 and 2, respectively. These findings lend additional support to the following conclusion of similar investigations ( 2 , 4 , 6 ): that virtual laboratories instruct students as effectively as hands-on laboratories.
Learning style preferences and course performance in an undergraduate physiology class
Authors: Dobson John L.
Published: November 2009

Learning styles may be classified according to the sensory modality that one most prefers to use when internalizing information. The four major sensory modalities are visual, aural or auditory, read/write, and kinesthetic. The purpose of this study was to investigate the relationship between preferred learning style, gender, and course scores in an undergraduate physiology class. Students from the fall 2008 and spring 2009 Applied Human Physiology courses completed an online questionnaire in which they were asked to both provide descriptive information about themselves (e.g., gender and major) and self-assess their preferred sensory modality. A total of 901 students completed the questionnaire, 75% of which were female and 25% were male. The results from a χ2-analysis (χ2= 9.59, P < 0.05) indicated that females and males had significantly different learning style preferences. Females most preferred visual learning (46%) followed by aural (27%), read/write (23%), and kinesthetic (4%). Males most preferred visual learning (49%) followed by read/write (29%), aural (17%), and kinesthetic (5%). There was also a significant relationship ( P < 0.05 by ANOVA) between preferred sensory modality and course scores. The mean overall course scores were 83.53 ± 8.25, 85.58 ± 8.18, 84.98 ± 7.78, and 76.70 ± 7.92 for those that preferred visual, aural, read/write, and kinesthetic modalities, respectively. These results support the findings of Wehrwein et al. ( 18 ): that female and male physiology students have different sensory modality preferences and that they provide the first step in determining if sensory modality preferences impact final course scores.
The renal renin-angiotensin system
Authors: Harrison-Bernard Lisa M.
Published: November 2009

The renin-angiotensin system (RAS) is a critical regulator of sodium balance, extracellular fluid volume, vascular resistance, and, ultimately, arterial blood pressure. In the kidney, angiotensin II exerts its effects to conserve salt and water through a combination of the hemodynamic control of renal blood flow and glomerular filtration rate and tubular epithelial cell sodium chloride and water transport mechanisms. Pharmacological inhibition of the actions of the RAS are widely used in the treatment of patients with hypertension, congestive heart failure, left ventricular dysfunction, pulmonary and systemic edema, diabetic nephropathy, cirrhosis of the liver, scleroderma, and migraines. Therefore, a thorough understanding of the influences of the RAS on normal renal physiology is of major importance for first-year medical students.
Improving the effectiveness of physiology record books as a learning tool for first-year medical students in India
Authors: Vyas Rashmi , Tharion Elizabeth , Sathishkumar Solomon
Published: November 2009

In compliance with the Medical Council of India, preclinical medical students maintain a record of their laboratory work in physiology. The physiology record books also contain a set of questions to be answered by the students. Faculty members and students had indicated that responding to these questions did not serve the intended purpose of being an effective learning tool. The purpose of this study was to obtain the views of the medical students and faculty members at our institution concerning the usefulness of responding to the questions and to gather suggestions for possible improvement. Data were collected through focus groups and questionnaires to first-year medical students and faculty members in physiology and were analyzed using qualitative and quantitative methods. The students and faculty members viewed the physiology record books as a potentially useful learning aid, but lack of time led the students to write the answers without understanding the topic rather than generating their own responses to the questions. Faculty members and students recommended that the students should write the responses to the questions on site during the practical classes, using relevant on-site resources and interacting with faculty members. The findings of the present study may be of value to other medical colleges in India and outside India with modifications based on their specific needs to improve the effectiveness of physiology record books as a learning tool.
The kidney and acid-base regulation
Authors: Koeppen Bruce M.
Published: November 2009

Since the topic of the role of the kidneys in the regulation of acid-base balance was last reviewed from a teaching perspective (Koeppen BM. Renal regulation of acid-base balance. Adv Physiol Educ 20: 132–141, 1998), our understanding of the specific membrane transporters involved in H+, HCO3−, and NH4+ transport, and especially how these transporters are regulated in response to systemic acid-base disorders, has advanced considerably. In this review, these new aspects of renal function are presented, as are the broader and more general concepts related to the role of the kidneys in maintaining the acid-base balance. It is intended that this review will assist those who teach this aspect of human physiology to first-year health profession students.
Active learning strategies to teach renal-cardiovascular integration with high student-to-teacher ratios
Authors: Brands Michael W. , Schumacher Lori
Published: November 2009

To address the challenge of increasing opportunities for active learning into a medical physiology course with ∼190 students enrolled, we chose an integrated approach. This was facilitated by the availability of a patient simulator facility at the School of Nursing at the Medical College of Georgia, and an ∼20-min simulation of acute hemorrhage on the simulators comprised the first of three components in our approach. The second component was a small-group problem-solving session that each group conducted immediately after their patient simulator session. It brought in the more complex physiological responses to acute hemorrhage using an exercise we designed using free downloadable simulation software from the Department of Physiology and Biophysics at the University of Mississippi Medical Center. The third component was a student worksheet exercise that was built around data collected from 12 students who volunteered to collect a 24-h urine sample and have blood pressure measured after 3 days on either high or low salt intake. The worksheet was completed independently, and the answers and student data formed the basis for a classroom lecture. The approach has met with increasingly positive reviews due to testing the first two components on second-year medical student volunteers before its implementation, keeping the first component as simple as possible, keeping the second component to <30 min, and continued revision of the third component to increase clinical context of the study questions. An integrated active learning approach can enhance student interest in integrating cardiovascular-renal physiology, particularly if faculty members are willing to revise the approach in response to student feedback.
A model of locomotor-respiratory coupling in quadrupeds
Authors: Giuliodori Mauricio J. , Lujan Heidi L. , Briggs Whitney S. , DiCarlo Stephen E.
Published: November 2009

Locomotion and respiration are not independent phenomena in running mammals because locomotion and respiration both rely on cyclic movements of the ribs, sternum, and associated musculature. Thus, constraints are imposed on locomotor and respiratory function by virtue of their linkage. Specifically, locomotion imposes mechanical constraints on breathing that require the respiratory cycle to be synchronized with gait. Thus, many mammals, including humans, synchronize respiration with the movement of the limbs during locomotion. For example, quadrupeds synchronize locomotor and respiratory cycles at a 1:1 ratio (stride/breath) over a wide range of speeds. Interestingly, quadrupeds maintain an almost constant stride frequency (and therefore respiratory frequency) at different speeds. To increase speed, quadrupeds lengthen their stride. Accordingly, to increase minute ventilation, quadrupeds must increase tidal volume since respiratory rate is coupled with stride frequency. We developed a simple, inexpensive, and easy to build model to demonstrate this concept. A model was chosen because models significantly enhance student understanding. Students are drawn into discussion by the power of learning that is associated with manipulating and thinking about objects. Building and using this model strengthen the concept that locomotor-respiratory coupling provides a basis for the appropriate matching of lung ventilation to running speed and metabolic power.
Explorations in statistics: the bootstrap
Authors: Curran-Everett Douglas
Published: November 2009

Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This fourth installment of Explorations in Statistics explores the bootstrap. The bootstrap gives us an empirical approach to estimate the theoretical variability among possible values of a sample statistic such as the sample mean. The appeal of the bootstrap is that we can use it to make an inference about some experimental result when the statistical theory is uncertain or even unknown. We can also use the bootstrap to assess how well the statistical theory holds: that is, whether an inference we make from a hypothesis test or confidence interval is justified.
Clinical physiology: a successful academic and clinical discipline is threatened in Sweden
Authors: Arheden Håkan
Published: November 2009

Clinical physiologists in Sweden are physicians (the majority with a PhD degree) with thorough training in system physiology and pathophysiology. They investigate patients in a functional approach and are engaged in basic and applied physiology teaching and research. In 1954, clinical physiology was founded as an independent academic and clinical discipline by the Swedish government to ensure “contact between routine clinical work and the scientific progression.” Up until 2008, clinical physiology was an independent clinical discipline but was then made a subdiscipline to radiology, a fundamentally different discipline. Individuals wishing to become clinical physiologists are required to be trained and certified as European radiologists, after which training and certification as clinical physiologists may be pursued. This means that radiologists without training in clinical physiology have become gatekeepers for future clinical physiologists. Unfortunately, this development takes place at a time when research and education in preclinical integrative physiology have diminished in favor of other organizational levels, such as cellular and molecular biology. The responsibilities for education and research in integrative human physiology have therefore mainly been transferred to clinical physiologists. Clinical physiology has been a successful independent clinical discipline in Sweden for the past 55 years and could serve as a model for other countries. Unless clinical physiologists regain control over their own discipline, systems physiology as a knowledge base and resource for patient care, education, and research will be severely impaired.
Chemistry misconceptions associated with understanding calcium and phosphate homeostasis
Authors: Cliff William H.
Published: November 2009

Successful learning of many aspects in physiology depends on a meaningful understanding of fundamental chemistry concepts. Two conceptual diagnostic questions measured student understanding of the chemical equilibrium underlying calcium and phosphate homeostasis. One question assessed the ability to predict the change in phosphate concentration when calcium ions were added to a saturated calcium phosphate solution. Fifty-two percent of the students correctly predicted that the phosphate concentration would decrease in accord with the common ion effect. Forty-two percent of the students predicted that the phosphate concentration would not change. Written explanations showed that most students failed to evoke the idea of competing chemical equilibria. A second question assessed the predicted change in calcium concentration after solid calcium phosphate was added to a saturated solution. Only 11% of the students correctly predicted no change in calcium concentration; 86% of the students predicted an increase, and many based their prediction on a mistaken application of Le Chatelier's principle to heterogeneous equilibria. These results indicate that many students possess misconceptions about chemical equilibrium that may hamper understanding of the processes of calcium and phosphate homeostasis. Instructors can help students gain greater understanding of these physiochemical phenomena by adopting strategies that enable students achieve more accurate conceptions of chemical equilibria.