bluuebunny/crossref_metadata_2025 huggingface dataset:
Gene polymorphism in transforming growth factor‐beta codon 10 is associated with susceptibility to Giardiasis
Authors: Taherkhani H. , Hajilooi M. , Fallah M. , Khyabanchi O. , Haidari M.
Published: August 2009

Secretory immunoglobulin A (S‐IgA) antibodies have a central role in anti‐Giardial defence. It has been demonstrated that transforming growth factor‐beta1 (TGF‐β1) stimulates B lymphocytes to produce and secrete S‐IgA. We sought to determine the association between TGF‐β1 polymorphism (T+869C) with susceptibility to Giardiasis. The TGF‐β1 genotypes and levels of salivary (S‐IgA) were analysed in individuals with Giardiasis (97 symptomatic and 57 asymptomatic) and controls (n = 92). Individuals with symptomatic Giardiasis had the lowest levels of S‐IgA compared to individuals in asymptomatic Giardiasis and control groups (97%, 73% and 43%, <1 g L−1, respectively, P = 0.002). The frequency of allele C and CC genotypes of TGF‐β1 polymorphism was significantly higher among symptomatic patients than asymptomatic and control groups. Logistic regression analysis demonstrated that the individuals homozygous for allele C of TGF‐β1 had a significantly higher risk for symptomatic Giardiasis with odds ratio of 2.76 (95% CI: 3.88, 1.71, P = 0.007). Among the participants with TT genotype per cent of individuals with S‐IgA level of more than 1 g L−1 was almost twice the percentage in CC genotype individuals (14% versus 7% respectively P = 0.01). Our data suggest that CC genotype of TGF‐β1 polymorphism at codon 10 is associated with occurrence of Giardiasis.
Silicon‐augmented resistance of plants to herbivorous insects: a review
Authors: Reynolds O.L. , Keeping M.G. , Meyer J.H.
Published: August 2009

Silicon (Si) is one of the most abundant elements in the earth's crust, although its essentiality in plant growth is not clearly established. However, the importance of Si as an element that is particularly beneficial for plants under a range of abiotic and biotic stresses is now beyond doubt. This paper reviews progress in exploring the benefits at two‐ and three‐trophic levels and the underlying mechanism of Si in enhancing the resistance of host plants to herbivorous insects. Numerous studies have shown an enhanced resistance of plants to insect herbivores including folivores, borers, and phloem and xylem feeders. Silicon may act directly on insect herbivores leading to a reduction in insect performance and plant damage. Various indirect effects may also be caused, for example, by delaying herbivore establishment and thus an increased chance of exposure to natural enemies, adverse weather events or control measures that target exposed insects. A further indirect effect of Si may be to increase tolerance of plants to abiotic stresses, notably water stress, which can in turn lead to a reduction in insect numbers and plant damage. There are two mechanisms by which Si is likely to increase resistance to herbivore feeding. Increased physical resistance (constitutive), based on solid amorphous silica, has long been considered the major mechanism of Si‐mediated defences of plants, although there is recent evidence for induced physical defence. Physical resistance involves reduced digestibility and/or increased hardness and abrasiveness of plant tissues because of silica deposition, mainly as opaline phytoliths, in various tissues, including epidermal silica cells. Further, there is now evidence that soluble Si is involved in induced chemical defences to insect herbivore attack through the enhanced production of defensive enzymes or possibly the enhanced release of plant volatiles. However, only two studies have tested for the effect of Si on an insect herbivore and third trophic level effects on the herbivore's predators and parasitoids. One study showed no effect of Si on natural enemies, but the methods used were not favourable for the detection of semiochemical‐mediated effects. Work recently commenced in Australia is methodologically and conceptually more advanced and an effect of Si on the plants' ability to generate an induced response by acting at the third trophic level was observed. This paper provides the first overview of Si in insect herbivore resistance studies, and highlights novel, recent hypotheses and findings in this area of research. Finally, we make suggestions for future research efforts in the use of Si to enhance plant resistance to insect herbivores.
Reliability and Validity of the Global Assessment of Relational Functioning (GARF) in a Psychiatric Family Therapy Clinic
Authors: Denton Wayne H. , Nakonezny Paul A. , Burwell Stephanie R.
Published: August 2009

The reliability and validity of the Diagnostic and Statistical Manual of Mental Disorders‐IV Global Assessment of Relational Functioning (GARF) was evaluated in consenting participants presenting to a family therapy training clinic. The purpose of this study was to (a) assess whether the GARF could be administered quickly in a marriage and family therapy training clinic, (b) assess the inter‐rater and internal reliability of GARF ratings of intake sessions, (c) examine the relationship of GARF ratings to established measures of relationship functioning, and (d) compare GARF ratings to a measure of depressive symptoms. Study participants completed the General Functioning Subscale of the Family Assessment Device (GFS/FAD), the Quality of Marriage Index (QMI), and the Center for Epidemiologic Studies–Depression Scale (CES‐D). After intake sessions were conducted with study participants, GARF ratings were made by an American Association for Marriage and Family Therapy Approved Supervisor or Supervisor‐in‐Training, a therapist trainee, and two observing trainees who had observed the session from behind a one‐way mirror. Cronbach’s coefficient alphas and the average intraclass correlation coefficients were both .82 when ratings of the supervisor and two observers were compared and .78 and .79, respectively, when ratings of the supervisor, two observers, and therapist were evaluated. There was significant agreement between GARF ratings made by the supervisor and therapist (but not observers) and scores on the GFS/FAD, QMI, and CES‐D. Results suggest that GARF ratings can be made quickly and reliably, especially among raters with greater clinical experience, and are related to measures of relational functioning and depression. Implications for research and marriage and family therapy training are discussed.
Seasonal nitrogen dynamics of Miscanthus×giganteus and Panicum virgatum
Authors: HEATON EMILY A. , DOHLEMAN FRANK G. , LONG STEPHEN P.
Published: August 2009

There is a tradeoff to consider when harvesting perennial biomass crops: harvest too late and yield declines, harvest too early and risk higher mineral contents, particularly nitrogen (N). Allowing the crop to completely senesce and recycle nutrients has several advantages, including improved feedstock quality and reduced fertilizer requirements, but it comes at a risk, particularly in temperate climates where snow and ice can reduce or destroy harvestable biomass. The effect of harvest time on the N concentration ([N]) and biomass of Panicum virgatum and Miscanthus×giganteus was evaluated at three sites in Illinois over two years. In both species [N] of standing biomass significantly declined with time (P<0.0001). Interestingly, there was no significant interaction effect of species and sample date on [N] (P=0.2888), but there was a highly significant interaction effect on the total N in standing biomass (P<0.0001). The amount of standing N was directly related to biomass yield. Seasonal changes in standing N differed among locations, suggesting that harvest time recommendations for N management depend on location. P. virgatum would have potentially removed as much as 187 kg N ha−1 if harvested green, and as little as 5 kg N ha−1 if harvested in late winter. Because of higher biomass yields, M. ×giganteus standing N ranged from 379 kg N ha−1 in June to <17 kg N ha−1 in February. Importantly, there was little overall change in [N] between an early winter (December) harvest and a late winter (February/March) harvest, indicating the benefits of N cycling in the system can be realized by end of the growing season and thus, at least from an N economy perspective, there is no reason to risk yield losses by delaying harvest over the winter.
The cervical wedge‐shaped lesion in teeth: a light and electron microscopic study
Authors: Daley TJ , Harbrow DJ , Kahler B , Young WG
Published: August 2009

Background:  The cervical non‐carious wedged‐shaped lesion is controversial in that its aetiology may involve attrition, erosion, abrasion and stress‐corrosion (abfraction). This study examined the histopathology of anterior teeth with cervical wedge‐shaped lesions by light and electron microscopy to elucidate their pathogenesis.

Methods:  Ten undecalcified human teeth with cervical lesions were available for investigation. Patency of the dentine tubules was tested using red dye penetration from the pulp chamber. The morphology of normal and sclerotic dentine adjacent to the cervical wedge‐shaped lesions was investigated by scanning electron microscopy. The numbers and diameters of dentinal tubules were measured at different levels beneath the surfaces of the lesions.

Results:  The gross and microscopic features of the worn teeth were described. Red dye penetration tests showed white tracts of sclerotic tubules contrasted with red tracts of patent tubules. Numbers of tubules per square area and diameters of patent and sclerotic tubules varied at different levels within the dentine due to deposits of intratubular dentine.

Conclusions:  The cervical wedge is shaped by interactions between acid wear, abrasion and dentinal sclerosis. No histopathological evidence of abfraction was found. Clinical diagnosis, conservation and restoration of non‐carious cervical lesions need to take into account the extent of sclerotic dentine beneath wedge‐shaped lesions.
Physical‐mechanical properties of glass ionomer cements indicated for atraumatic restorative treatment
Authors: Bonifácio CC , Kleverlaan CJ , Raggio DP , Werner A , De Carvalho RCR , Van Amerongen WE
Published: August 2009

Background:  This study evaluated mechanical properties of glass ionomer cements (GICs) used for atraumatic restorative treatment. Wear resistance, Knoop hardness (Kh), flexural (Fs) and compressive strength (Cs) were evaluated. The GICs used were Riva Self Cure (RVA), Fuji IX (FIX), Hi Dense (HD), Vitro Molar (VM), Maxxion R (MXR) and Ketac Molar Easymix (KME).

Methods:  Wear was evaluated after 1, 4, 63 and 365 days. Two‐way ANOVA and Tukey post hoc tests (P = 0.05) analysed differences in wear of the GICs and the time effect. Fs, Cs, and Kh were analysed with one‐way ANOVA.

Results:  The type of cement (p < 0.001) and the time (p < 0.001) had a significant effect on wear. In early‐term wear and Kh, KME and FIX presented the best performance. In long‐term wear, Fs and Cs, KME, FIX and HD had the best performance. Strong explanatory power between Fs and the Kh (r2 = 0.85), Cs and the Kh (r2 = 0.82), long‐term wear and Fs of 24 h (r2 = 0.79) were observed.

Conclusions:  The data suggested that KME and FIX presented the best in vitro performance. HD showed good results except for early‐term wear.
Erosive potential of beverages sold in Australian schools
Authors: Cochrane NJ , Cai F , Yuan Y , Reynolds EC
Published: August 2009

Background:  Dental erosion is an increasingly prevalent problem in Australia. The aim of this study was to analyse the composition and erosive potential of beverages sold for consumption in Victorian schools.

Methods:  Fifteen drinks were selected and analysed to determine their pH, titratable acidity and ionic composition (calcium, fluoride and inorganic phosphate). The erosive potential of the beverages was measured by analysing weight loss, surface loss and the release of calcium ions from human enamel following a 30‐minute or 24‐hour exposure. The association of the chemical parameters with the measures of erosion was determined using Spearman’s rank correlation.

Results:  All beverages tested except the milks and the bottled water produced significant dental erosion in vitro. The only chemical parameter that correlated significantly with all measures of erosion was the initial pH of the beverage (p < 0.01). Levels of fluoride similar to those of Australian reticulated water were found in the carbonated beverages.

Conclusions:  The majority of the tested beverages sold from school canteens exhibited erosive potential.
Periosteal pedicle graft for the treatment of gingival recession defects: a novel technique
Authors: Mahajan A
Published: August 2009

Background:  The periosteum is a highly cellular connective tissue with rich vascularity and regenerative potential. These qualities make it a suitable autogenous graft. A technique utilizing autogenous periosteal pedicle graft (PPG) for the treatment of gingival recession defects is described.

Methods:  Four patients with Miller Class I and II recessions ≥ 3 mm were treated utilizing PPG.

Results:  At the end of one year, all defects were completely covered.

Conclusions:  The PPG technique can be used for the treatment of gingival recession defects successfully.
Early load mandibular hybrid prosthesis using the Ohio State University acrylic frame requiring no final impression
Authors: Turkyilmaz I , Suarez JC , Company AM , McGlumphy EA
Published: August 2009

Background:  Although immediate/early loading protocols for dental implants have presented encouraging outcomes, immediate loading procedures may cause discomfort to the patient and may increase the possibility of damage to the surgical site during the impression procedures. The aim of this study was to describe an alternative technique to fabricate a mandibular hybrid prosthesis in three or four days without making any final impression and to evaluate the outcomes of this technique.

Methods:  Seven patients aged 41 to 71 years (mean age, 58 ± 11) were considered for this study. Each patient received five implants for the reconstruction of the edentulous mandible. These implants were placed in the anterior region of an edentulous mandible and restored with a final mandibular hybrid prosthesis in four days using the Ohio State University (OSU) acrylic frame requiring no final impression procedure. The patients were followed up to 19 months after implant placement.

Results:  No implants were lost, no technical complications were observed and only minor marginal bone loss was noted after an average 15 months.

Conclusions:  This clinical study shows that the OSU acrylic frame, which can easily be customized and accommodates variability in arch form, may be an alternative method to restore any edentulous mandible with an early load mandibular hybrid prosthesis.
On the expressiveness and complexity of randomization in finite state monitors
Authors: Chadha Rohit , Sistla A. Prasad , Viswanathan Mahesh
Published: August 2009

In this article, we introduce the model of
finite state probabilistic monitors
(FPM), which are finite state automata on infinite strings that have probabilistic transitions and an absorbing reject state. FPMs are a natural automata model that can be seen as either randomized run-time monitoring algorithms or as models of open, probabilistic reactive systems that can fail. We give a number of results that characterize, topologically as well as with respect to their computational power, the sets of languages recognized by FPMs. We also study the emptiness and universality problems for such automata and give exact complexity bounds for these problems.
On approximating the ideal random access machine by physical machines
Authors: Bilardi Gianfranco , Ekanadham Kattamuri , Pattnaik Pratap
Published: August 2009

The capability of the
Random Access Machine
(RAM) to execute any instruction in constant time is not realizable, due to fundamental physical constraints on the minimum size of devices and on the maximum speed of signals. This work explores how well the ideal RAM performance can be approximated, for significant classes of computations, by machines whose building blocks have constant size and are connected at a constant distance.

A novel memory structure is proposed, which is
pipelined
(can accept a new request at each cycle) and
hierarchical
, exhibiting optimal latency
a
(
x
) =
O
(
x

1/
d

) to address
x
, in
d
-dimensional realizations.

In spite of block-transfer or other memory-pipeline capabilities, a number of previous machine models do not achieve a full overlap of memory accesses. These are examples of machines with
explicit data movement
. It is shown that there are
direct-flow
computations (without branches and indirect accesses) that require time superlinear in the number of instructions, on all such machines.

To circumvent the explicit-data-movement constraints, the
Speculative Prefetcher
(SP) and the
Speculative Prefetcher and Evaluator
(SPE) processors are developed. Both processors can execute any
direct-flow
program in linear time. The SPE also executes in linear time a class of loop programs that includes many significant algorithms. Even quicksort, a somewhat irregular, recursive algorithm admits a linear-time SPE implementation. A relation between instructions called
address dependence
is introduced, which limits memory-access overlap and can lead to superlinear time, as illustrated with the classical merging algorithm.
A unified approach to scheduling on unrelated parallel machines
Authors: Kumar V. S. Anil , Marathe Madhav V. , Parthasarathy Srinivasan , Srinivasan Aravind
Published: August 2009

We develop a single rounding algorithm for scheduling on unrelated parallel machines; this algorithm works well with the known linear programming-, quadratic programming-, and convex programming-relaxations for scheduling to minimize completion time, makespan, and other well-studied objective functions. This algorithm leads to the following applications for the general setting of unrelated parallel machines: (i) a bicriteria algorithm for a schedule whose weighted completion-time and makespan
simultaneously
exhibit the current-best individual approximations for these criteria; (ii) better-than-two approximation guarantees for scheduling to minimize the

L
p

norm of the vector of machine-loads, for all 1 <
p
< ∞; and (iii) the first constant-factor multicriteria approximation algorithms that can handle the weighted completion-time and
any
given collection of integer

L
p

norms. Our algorithm has a natural interpretation as a melding of linear-algebraic and probabilistic approaches. Via this view, it yields a common generalization of rounding theorems due to Karp et al. [1987] and Shmoys & Tardos [1993], and leads to improved approximation algorithms for the problem of scheduling with resource-dependent processing times introduced by Grigoriev et al. [2007].
SMACK
Authors: Dutta Aveek , Saha Dola , Grunwald Dirk , Sicker Douglas
Published: August 2009

Network protocol designers, both at the physical and network level, have long considered interference and simultaneous transmission in wireless protocols as a problem to be avoided. This, coupled with a tendency to emulate wired network protocols in the wireless domain, has led to artificial limitations in wireless networks.

In this paper, we argue that wireless protocols can exploit simultaneous transmission to reduce the cost of reliable multicast by orders of magnitude. With an appropriate application interface, simultaneous transmission can also greatly speed up common group communication primitives, such as anycast, broadcast, leader election and others.

The proposed method precisely fits into the domain of directly reachable nodes where many group communication mechanisms are commonly used in routing protocols and other physical-layer mechanisms. We demonstrate how simultaneous transmission can be used to implement a reliable broadcast for an infrastructure and peer-to-peer network using a prototype reconfigurable hardware. We also validate the notion of using simple spectrum sensing techniques to distinguish multiple transmissions. We then describe how the mechanism can be extended to solve group communication problems and the challenges inherent to build innovative protocols which are faster and reliable at the same time.
PortLand
Authors: Niranjan Mysore Radhika , Pamboris Andreas , Farrington Nathan , Huang Nelson , Miri Pardis , Radhakrishnan Sivasankar , Subramanya Vikram , Vahdat Amin
Published: August 2009

This paper considers the requirements for a scalable, easily manageable, fault-tolerant, and efficient data center network fabric. Trends in multi-core processors, end-host virtualization, and commodities of scale are pointing to future single-site data centers with millions of virtual end points. Existing layer 2 and layer 3 network protocols face some combination of limitations in such a setting: lack of scalability, difficult management, inflexible communication, or limited support for virtual machine migration. To some extent, these limitations may be inherent for Ethernet/IP style protocols when trying to support arbitrary topologies. We observe that data center networks are often managed as a single logical network fabric with a known baseline topology and growth model. We leverage this observation in the design and implementation of PortLand, a scalable, fault tolerant layer 2 routing and forwarding protocol for data center environments. Through our implementation and evaluation, we show that PortLand holds promise for supporting a ``plug-and-play" large-scale, data center network.
SmartRE
Authors: Anand Ashok , Sekar Vyas , Akella Aditya
Published: August 2009

Application-independent Redundancy Elimination (RE), or identifying and removing repeated content from network transfers, has been used with great success for improving network performance on enterprise access links. Recently, there is growing interest for supporting RE as a network-wide service. Such a network-wide RE service benefits ISPs by reducing link loads and increasing the effective network capacity to better accommodate the increasing number of bandwidth-intensive applications. Further, a networkwide RE service democratizes the benefits of RE to all end-to-end traffic and improves application performance by increasing throughput and reducing latencies.

While the vision of a network-wide RE service is appealing, realizing it in practice is challenging. In particular, extending single vantage-point RE solutions designed for enterprise access links to the network-wide case is inefficient and/or requires modifying routing policies. We present SmartRE, a practical and efficient architecture for network-wide RE. We show that SmartRE can enable more effective utilization of the available resources at network devices, and thus can magnify the overall benefits of network-wide RE. We prototype our algorithms using Click and test our framework extensively using several real and synthetic traces.
Practical, distributed channel assignment and routing in dual-radio mesh networks
Authors: Dhananjay Aditya , Zhang Hui , Li Jinyang , Subramanian Lakshminarayanan
Published: August 2009

Realizing the full potential of a multi-radio mesh network involves two main challenges: how to assign channels to radios at each node to minimize interference and how to choose high throughput routing paths in the face of lossy links, variable channel conditions and external load. This paper presents ROMA, a practical, distributed channel assignment and routing protocol that achieves good multi-hop path performance between every node and one or more designated gateway nodes in a dual-radio network. ROMA assigns non-overlapping channels to links along each gateway path to eliminate intra-path interference. ROMA reduces inter-path interference by assigning different channels to paths destined for different gateways whenever possible. Evaluations on a 24-node dual-radio testbed show that ROMA achieves high throughput in a variety of scenarios.
Pathlet routing
Authors: Godfrey P. Brighten , Ganichev Igor , Shenker Scott , Stoica Ion
Published: August 2009

We present a new routing protocol, pathlet routing, in which networks advertise fragments of paths, called pathlets, that sources concatenate into end-to-end source routes. Intuitively, the pathlet is a highly flexible building block, capturing policy constraints as well as enabling an exponentially large number of path choices. In particular, we show that pathlet routing can emulate the policies of BGP, source routing, and several recent multipath proposals. This flexibility lets us address two major challenges for Internet routing: scalability and source-controlled routing. When a router's routing policy has only "local" constraints, it can be represented using a small number of pathlets, leading to very small forwarding tables and many choices of routes for senders. Crucially, pathlet routing does not impose a global requirement on what style of policy is used, but rather allows multiple styles to coexist. The protocol thus supports complex routing policies while enabling and incentivizing the adoption of policies that yield small forwarding plane state and a high degree of path choice.
DIRC
Authors: Liu Xi , Sheth Anmol , Kaminsky Michael , Papagiannaki Konstantina , Seshan Srinivasan , Steenkiste Peter
Published: August 2009

The demand for wireless bandwidth in indoor environments such as homes and offices continues to increase rapidly. Although wireless technologies such as MIMO can reach link throughputs of 100s of Mbps (802.11n) for a single link, the question of how we can deliver high throughput to a large number of densely-packed devices remains an open problem. Directional antennas have been shown to be an effective way to increase spatial reuse, but past work has focused largely on outdoor environments where the interactions between wireless links can usually be ignored. This assumption is not acceptable in dense indoor wireless networks since indoor deployments need to deal with rich scattering and multipath effects. In this paper we introduce DIRC, a wireless network design whose access points use phased array antennas to achieve high throughput in dense, indoor environments. The core of DIRC is an algorithm that increases spatial reuse and maximizes overall network capacity by optimizing the orientations of a network of directional antennas. We implemented DIRC and evaluated it on a nine node network in an enterprise setting. Our results show that DIRC improves overall network capacity in indoor environments, while being flexible enough to adapt to node mobility and changing traffic workloads.
Stable and flexible iBGP
Authors: Flavel Ashley , Roughan Matthew
Published: August 2009

Routing oscillation is highly detrimental. It can decrease performance and lead to a high level of update churn placing unnecessary workload on router the problem is distributed between many providers. However, iBGP --- the routing protocol used to distribute routes inside a single Autonomous System --- has also been shown to oscillate. Despite the fact that iBGP is configured by a single provider according to apparently straight forward rules, more than eight years of research has not solved the problem of iBGP oscillation. Various solutions have been proposed but they all lack critical features: either they are complicated to implement, restrict routing flexibility, or lack guarantees of stability. In this paper we propose a very simple adaptation to the BGP decision process. Despite its simplicity and negligible cost we prove algebraically that it prevents iBGP oscillation. We extend the idea to provide routing flexibility, such as respecting the MED attribute, without sacrificing network stability.
Modeling and understanding end-to-end class of service policies in operational networks
Authors: Sung Yu-Wei Eric , Lund Carsten , Lyn Mark , Rao Sanjay G. , Sen Subhabrata
Published: August 2009

Business and economic considerations are driving the extensive use of service differentiation in Virtual Private Networks (VPNs) operated for business enterprises today. The resulting Class of Service (CoS) designs embed complex policy decisions based on the described priorities of various applications, extent of bandwidth availability, and cost considerations. These inherently complex high-level policies are realized through low-level router configurations. The configuration process is tedious and error-prone given the highly intertwined nature of CoS configuration, the multiple router configurations over which the policies are instantiated, and the complex access control lists (ACLs) involved. Our contributions include (i) a formal approach to modeling CoS policies from router configuration files in a precise manner; (ii) a practical and computationally efficient tool that can determine the CoS treatment received by an arbitrary set of flows across multiple routers; and (iii) a validation of our approach in enabling applications such as troubleshooting, auditing, and visualization of network-wide CoS design, using router configuration data from a cross-section of 150 diverse enterprise VPNs. To our knowledge, this is the first effort aimed at modeling and analyzing CoS configurations.
Accidental Homeschoolers
Authors: Edelson John , Arnold Mary
Published: August 2009

The media creates an image of homeschoolers as a backward-looking dogmatic group who are withdrawing from mainstream society, but this is far from the truth. Indeed, homeschoolers are often progressive, pragmatic, highly sociable, and enthusiastic e-learning families. This article describes the path many parents have taken after placing their children in traditional schools, becoming dissatisfied, and then shifting to homeschooling as an 'accidental' change in direction.
chmod 777 education
Authors: Santos Carlos , Pedro Luís
Published: August 2009

In 2005, a few months after Tim O'Reilly crafted the term Web 2.0 and the discussion about Web 1.0 versus Web 2.0 emerged, IBM's James Snell wrote a short post explaining his view about the Web 2.0 concept. He used a brief Unix/Linux command -- chmod 777 Web -- to convey the message that Web 2.0 is all about granting users full-access privileges to the Web. His thought-provoking comments got us thinking. What would happen if we executed a "chmod 777 education" command to provide openness to education?
Long Live Instructor-Led Learning
Authors: Carliner Saul
Published: August 2009

In March 2009, the monthly question on ASTD's Learning Circuits blog wonders what training will look like in 2019. Nearly all the contributors predicted the death of the classroom. Before you buy that, perhaps I can interest you in some mortgage-backed securities? Consider the case for the death of the classroom to be about as strong as those securities.
Reminding and e-Learning
Authors: Schank Roger C.
Published: August 2009

'How do we get reminded?' is an important question for thinking about how real knowledge management should work. To make the computer really useful for work and for learning, we must think about building a reminding machine. A reminding machine would have in it thousands of stories from experts in various areas of life telling about important aspects of their lives that have lessons about life in them, the kind of stories you tell to colleagues or to students. What they would have in common would be lessons that follow from them about what to do if something like this happened again.
The World is Open for a Reason
Authors: Bonk Curtis J.
Published: August 2009

The educational world has become filled with millions of pieces of free and open content. The momentum for open education quickly accelerated in the early part of this decade when MIT announced its OpenCourseWare initiative and dozens of other colleges and universities around the world joined in the cause. These open educational resources have made a huge impact on the educational possibilities of young learners as well as retirees looking to build upon their past educational experiences. Curtis J. Bonk offers 30 reasons why there is so much excitement for open education today.
The Cost of E-Learning
Authors: Schechter Howard B.
Published: August 2009

E-learning is a business activity. It has a value to the business, a start-up cost, and running costs. The costs must be managed if the program is to stay within budget and yield an adequate return on investment. The question of start-up versus ongoing costs can best be answered if the program scope can be defined for the first two or three years. First-year costs are high, while ongoing costs are typically lower. Return on the time and money invested are typically realized toward the end of the first year. Second-year returns are higher as more courses are offered and the subscriber base expands. The answers to questions of cost are usually broad and rough at the outset and then become more refined as the project comes into focus.
Teaching and practicing computer science at the university level
Authors: Boute Raymond
Published: August 2009

Universities offering Computing Science curricula should do so at the university level. Taking pragmatic shortcuts causes stagnation in professional practice. The essential element is the pervasive presence throughout the curriculum of mathematical modelling, which is the role of Formal Methods in its original sense. Mathematical fundamentals and concepts are crucial, software tools are auxiliary and even misleading without the former. Recommendations are given for curriculum structure, specific key courses and attitudes to instil in students and educators. Comparison with other approaches is made. A conclusion is that CS curricula should break outside the limitations caused by conservative policy makers but also self-imposed ones.
An introductory course on programming based on formal specification and program calculation
Authors: Blanco Javier , Losano Leticia , Aguirre Nazareno , Novaira María Marta , Permigiani Sonia , Scilingo Gastón
Published: August 2009

We report on our experience in teaching introductory courses on programming based on formal specification and program calculation, in two different Computer Science programmes. We favour the use of logic as a tool, the notion of program as a formal entity, as well as some issues associated with efficiency. We also review and use in practical cases some program transformation strategies, such as generalisation, tupling and modularisation. We describe our approach, its advantages and drawbacks. Furthermore, we present some preliminary results from an ongoing qualitative research which intends to characterise, describe and understand the students' experiences when taking these courses.
A simple refinement-based method for constructing algorithms
Authors: Méry Dominique
Published: August 2009

The Event B modelling language provides a framework for teaching programming methodology based on the famous pre/post-specifications, together with the refinement. We illustrate the call-as-event pattern for helping users to use Event B. As teacher, we are using students to evaluate our methodology and we give comments in italic, when we have got reactions from our students: a given definition, a concept related to our methodology, for instance. We discuss points related to our lectures at different levels of the university, mainly master. Simple case studies illustrate the teaching methodology based on interactive proofs.
Proglets for first-year programming in Java
Authors: Edmondson Carol
Published: August 2009

Applets are little applications. Proglets are little programs. The author advocates the use of proglets in first-year programming courses to encourage students to investigate aspects of the language being taught, to test (parts of) algorithms, and to have fun. The writing of proglets allows beginning students to concentrate on their current concerns without being overwhelmed by the requirement to write assignment quality programs worthy of a fully-trained software engineer. The author has used proglets during three semesters to help students in repeat offerings of first-year programming courses which used Java as the teaching language.
Analyzing CS competencies using the SOLO taxonomy
Authors: Brabrand Claus , Dahl Bettina
Published: August 2009

We have used the SOLO Taxonomy to analyze 5,608 competencies stemming from 734 courses from the faculties of science at Aarhus University and University of Southern Denmark. Both faculties have formulated learning outcomes using this taxonomy. This has made it possible to systematically analyze competencies and compare different science subjects. In this talk, we will explain the analysis and outline our main findings.
Freedom of choice as motivational factor for active learning
Authors: Radenski Atanas
Published: August 2009

Freedom to choose what, when, and how to contribute in a learning process can motivate students to actively engage and achieve more in their studies. However, freedom of choice complicates course management and may deter instructors from allowing such freedom. Our approach is to utilize existing functionality of course management systems such as Moodle to automatically facilitate and coordinate free student choices and provide much needed relief for instructors at the same time. Using Moodle we have developed novel digital study packs that blend freedom of choice with guidance and control. Our survey shows that assisted freedom of choice is ranked highest in 51% of student responses -- in contrast to unlimited choice at 28% or no choice at all at 21%. Experience reported in this paper may be beneficial for instructors who would like to expand their courses with new motivational learning techniques.
Democracy in the classroom
Authors: Blaheta Don
Published: August 2009

Selecting a first-day activity for CS1 is an important way to set the scene for an introduction to computer science. This paper presents the task of counting votes as an accessible vehicle for lessons on algorithms, data management, parallel processing, and other key computational ideas.
Engaging students in specification and reasoning
Authors: Sitaraman Murali , Hallstrom Jason O. , White Jarred , Drachova-Strang Svetlana , Harton Heather K. , Leonard Dana , Krone Joan , Pak Rich
Published: August 2009

We introduce a "hands-on" experimentation approach for teaching mathematical specification and reasoning principles in a software engineering course. The approach is made possible by computer-aided analysis and reasoning tools that help achieve three central software engineering learning outcomes: (i) Learning to read specifications by creating test points using only specifications; (ii) Learning to use formal specifications in team software development while developing participating components independently; and (iii) Learning the connections between software and mathematical analysis by proving verification conditions that establish correctness for software components. Experimentation and evaluation results from two institutions show that our approach has had a positive impact.
Software reuse and plagiarism
Authors: Gibson J. Paul
Published: August 2009

In general, university guidelines or policies on plagiarism are not sufficiently detailed to cope with the technical complexity of software. Software plagiarism can have a significant impact on a student's degree result, particularly in courses were there is a significant emphasis on large-scale projects. We argue that a policy for software reuse is the most explicit, and fair, way of overcoming this problem. In our policy, we specify the notion of software to cover all the documents that are generally built during the engineering of a software system -- analysis, requirements, validation, design, verification, implementation and tests. Examples are used to show acceptable and unacceptable forms of reuse, mostly at the design, testing and implementation stages. These examples are represented in Java, although they should be easily understood by anyone with software engineering experience. We conclude with a simple code of practice for reuse of software based on a file-level policy, combined with emphasis on re-using only what is rigorously verified.
A "communication skills for computer scientists" course
Authors: Blume Lil , Baecker Ron , Collins Christopher , Donohue Aran
Published: August 2009

This paper describes "Communication Skills for Computer Scientists," a novel undergraduate course at the University of Toronto. We describe in detail the three major instructional streams of the course: writing, speaking, and interpersonal communications. We present a novel approach to teaching writing, interactive multimedia web technology to teach public speaking, and specific interpersonal skills training as the integral parts of the course. We contribute a detailed description of the curriculum and report measures of success, both quantitative data and reactions from students in their own words.
Free technology academy
Authors: Megias David , Tebbens Wouter , Bijlsma Lex , Santanach Francesc
Published: August 2009

More and more people and organisations embrace Free Software (FS) and Open Standards (OS). However a lack of knowledge holds back their massive adoption. The Free Technology Academy will address this by setting up a virtual campus offering course modules on these topics to become a showcase of a virtual campus based on FS, OS and the use of Open Educational Resources. This distance learning programme will enable IT professionals, students, teachers and decision makers to upgrade knowledge and acquire relevant skills on free technologies. The FTA is realised by an international consortium and welcomes other interested parties to join the network.
Relating research and teaching
Authors: White Su , Irons Alastair
Published: August 2009

The relationship between research and teaching has possible benefits and inherent tensions. Exploring the potentially beneficial relationship is of interest and possible value to faculty, students, and stakeholders. Much of the existing literature has described approaches using a vocabulary derived from the soft/applied social science fields of study, a view-point which may in some ways be problematic. This paper examines the relationship between research and teaching in the undergraduate curriculum from a perspective of the computing disciplines. It compares and contrasts evidence of the beliefs and experiences of faculty about the relationship between research and teaching. It presents and analyses the result of surveys which gathered data to explore their understandings inter-relationship of research and teaching; in the curriculum; and as it is delivered, and experienced in the lab, seminar room and lecture hall. This research builds on existing work developed in a preliminary study which examined ways in which synergies between research and teaching could be achieved, particularly in the 'hard/applied' areas of the curriculum. It analyses data from the 'research-intensive' and the 'teaching-intensive' institutions. Having identified typical activities in the computing disciplines, it places them in the context of existing theoretical models.
The use of a controlled wireless testbed in courses
Authors: Steenkiste Peter
Published: August 2009

Wireless networking has become a popular topic in both undergraduate and graduate courses. However, putting together good assignments in wireless networking is difficult because the behavior of the wireless network depends strongly on the physical environment. We have used a wireless networking testbed based on signal propagation emulation in a number of wireless networking courses. The wireless emulator supports highly realistic experiments, while also offering a high degree of control and repeatability. This combination is very useful in a teaching context. In this paper we give an overview of the wireless emulator and we describe how it was used to support assignments and open-ended projects in several courses.
802.11 wireless experiments in a virtual world
Authors: Sturgeon Thomas , Allison Colin , Miller Alan
Published: August 2009

This paper describes the design and implementation of an 802.11 wireless laboratory within a Multi-User Virtual Environment (MUVE). The laboratory allows students and lecturers to create their own 802.11 scenarios by: i) selecting and placing components such as base stations and laptops within the immersive 3D landscape; ii) defining how traffic flows between these different network components; and iii) where appropriate specifying the movements of nodes. This information is sent outside of the MUVE and translated into a set of commands for the ns2 simulator, which then generates the simulation. The results of the simulation are sent back to the MUVE, where a 3D animation of the wireless communication is presented to learners interacting with the system. Learners are therefore able to set up and observe wireless phenomena such as the hidden and exposed node problems and to experiment by changing parameters such as packet loss and RTS/CTS threshold. The enabling framework behind the laboratory takes advantage of language independent, distributed resource management and stateful interaction through the use of web services.
Interleaved pattern composition and scaffolded learning
Authors: Ginat David
Published: August 2009

One of the essential skills required in the design of computer programs is the composition of design patterns in an interleaved way. We expect both beginners and senior students to demonstrate competence with this skill. Are they competent? Not quite. We found that both novices and seniors demonstrate disturbing difficulties with interleaved pattern composition. In order to address these difficulties, we developed a scaffolding instruction approach, which we applied with students. We display our findings, our approach, and the approach implementation.
Active learning of greedy algorithms by means of interactive experimentation
Authors: Velázquez-Iturbide J. Ángel , Pérez-Carrasco Antonio
Published: August 2009

Greedy algorithms are one of the most common algorithm design techniques. Despite their apparent simplicity, their design is a demanding task. As a consequence, they are usually taught and learnt in a passive way. In this paper, we make a new proposal aimed at active learning of greedy algorithms. The paper contains two main contributions. First, we introduce a novel approach to their active learning, based on experimentation with and evaluation of alternative greedy strategies for a given problem. Second, we present a family of interactive assistants designed to support this approach. The assistants were evaluated for their usability in real lab situations, having obtained high scores from students as well as useful information to enhance them.
Developing programming skills by using interactive learning objects
Authors: Villalobos Jorge A. , Calderon Nadya A. , Jiménez Camilo H.
Published: August 2009

After several years of teaching programming using an active learning approach, we present our Interactive Learning Objects (ILOs) as one of the components that reinforce our pedagogical model, by supporting the generation of high-level programming skills. In this paper, we suggest a multi-dimension taxonomy for ILOs and present the experimentation developed to evaluate the impact of these objects within our CS courses
Further evidence of a relationship between explaining, tracing and writing skills in introductory programming
Authors: Lister Raymond , Fidge Colin , Teague Donna
Published: August 2009

This paper reports on a replication of earlier studies into a possible hierarchy of programming skills. In this study, the students from whom data was collected were at a university that had not provided data for earlier studies. Also, the students were taught the programming language "Python", which had not been used in earlier studies. Thus this study serves as a test of whether the findings in the earlier studies were specific to certain institutions, student cohorts, and programming languages. Also, we used a non-parametric approach to the analysis, rather than the linear approach of earlier studies. Our results are consistent with the earlier studies. We found that students who cannot trace code usually cannot explain code, and also that students who tend to perform reasonably well at code writing tasks have also usually acquired the ability to both trace code and explain code.