Showing papers by "Acadia University published in 2013"

EAACK—A Secure Intrusion-Detection System for MANETs

Abstract: The migration to wireless network from wired network has been a global trend in the past few decades. The mobility and scalability brought by wireless network made it possible in many applications. Among all the contemporary wireless networks, Mobile Ad hoc NETwork (MANET) is one of the most important and unique applications. On the contrary to traditional network architecture, MANET does not require a fixed network infrastructure; every single node works as both a transmitter and a receiver. Nodes communicate directly with each other when they are both within the same communication range. Otherwise, they rely on their neighbors to relay messages. The self-configuring ability of nodes in MANET made it popular among critical mission applications like military use or emergency recovery. However, the open medium and wide distribution of nodes make MANET vulnerable to malicious attackers. In this case, it is crucial to develop efficient intrusion-detection mechanisms to protect MANET from attacks. With the improvements of the technology and cut in hardware costs, we are witnessing a current trend of expanding MANETs into industrial applications. To adjust to such trend, we strongly believe that it is vital to address its potential security issues. In this paper, we propose and implement a new intrusion-detection system named Enhanced Adaptive ACKnowledgment (EAACK) specially designed for MANETs. Compared to contemporary approaches, EAACK demonstrates higher malicious-behavior-detection rates in certain circumstances while does not greatly affect the network performances.

Lifelong Machine Learning Systems: Beyond Learning Algorithms

Abstract: Lifelong Machine Learning, or LML, considers systems that can learn many tasks from one or more domains over its lifetime. The goal is to sequentially retain learned knowledge and to selectively transfer that knowledge when learning a new task so as to develop more accurate hypotheses or policies. Following a review of prior work on LML, we propose that it is now appropriate for the AI community to move beyond learning algorithms to more seriously consider the nature of systems that are capable of learning over a lifetime. Reasons for our position are presented and potential counter-arguments are discussed. The remainder of the paper contributes by defining LML, presenting a reference framework that considers all forms of machine learning, and listing several key challenges for and benefits from LML research. We conclude with ideas for next steps to advance the field.

Standard methods for maintaining adult Apis mellifera in cages under in vitro laboratory conditions

Abstract: SummaryAdult honey bees are maintained in vitro in laboratory cages for a variety of purposes. For example, researchers may wish to perform experiments on honey bees caged individually or in groups to study aspects of parasitology, toxicology, or physiology under highly controlled conditions, or they may cage whole frames to obtain newly emerged workers of known age cohorts. Regardless of purpose, researchers must manage a number of variables, ranging from selection of study subjects (e.g. honey bee subspecies) to experimental environment (e.g. temperature and relative humidity). Although decisions made by researchers may not necessarily jeopardize the scientific rigour of an experiment, they may profoundly affect results, and may make comparisons with similar, but independent, studies difficult. Focusing primarily on workers, we provide recommendations for maintaining adults under in vitro laboratory conditions, whilst acknowledging gaps in our understanding that require further attention. We specificall...

Exploitation of Long-Lived 3IL Excited States for Metal–Organic Photodynamic Therapy: Verification in a Metastatic Melanoma Model

Abstract: Members of a family of Ru(II)-appended pyrenylethynylene dyads were synthesized, characterized according to their photophysical and photobiological properties, and evaluated for their collective potential as photosensitizers for metal–organic photodynamic therapy. The dyads in this series possess lowest-lying 3IL-based excited states with lifetimes that can be tuned from 22 to 270 μs in fluid solution and from 44 to 3440 μs in glass at 77 K. To our knowledge, these excited-state lifetimes are the longest reported for Ru(II)-based dyads containing only one organic chromophore and lacking terminal diimine groups. These excited states proved to be extremely sensitive to trace amounts of oxygen, owing to their long lifetimes and very low radiative rates. Herein, we demonstrate that 3IL states of this nature are potent photodynamic agents, exhibiting the largest photocytotoxicity indices reported to date with nanomolar light cytotoxicities at very short drug-to-light intervals. Importantly, these new agents ar...

Mercury biomagnification through food webs is affected by physical and chemical characteristics of lakes.

Abstract: Mercury (Hg) contamination in aquatic systems remains a global concern because the organic form, methyl Hg (MeHg), can biomagnify to harmful concentrations in fish, fish-eating wildlife, and humans. Food web transfer of MeHg has been explored using models of log MeHg versus relative trophic position (nitrogen isotopes, δ(15)N), but regression slopes vary across systems for unknown reasons. In this study, MeHg biomagnification was determined for 11 lake food webs in Kejimkujik National Park, Nova Scotia, Canada, and compared to physical and chemical lake characteristics using principal component and multiple regression analyses. MeHg biomagnification (regression slopes of log MeHg versus baseline-adjusted δ(15)N for fishes and invertebrates) varied significantly across lakes and was higher in systems with lower aqueous nutrient/MeHg/chloride scores. This is one of the largest, consistent data sets available on MeHg biomagnification through temperate lake food webs and the first study to use a principal component and multiple regression approach to understand how lake chemical and physical characteristics interact to affect biomagnification among systems. Overall, our results show that the magnitude of MeHg biomagnification through lake food webs is related to the chemical and physical characteristics of the systems, but the underlying mechanisms warrant further investigation.

Social influence and knowledge management systems use: evidence from panel data

Abstract: Theory suggests that coworkers may influence individuals' technology use behaviors, but there is limited research in the technology diffusion literature that explicates how such social influence processes operate after initial adoption. We investigate how two key social influence mechanisms (identification and internalization) may explain the growth over time in individuals' use of knowledge management systems (KMS)--a technology that because of its publicly visible use provides a rich context for investigating social influence. We test our hypotheses using longitudinal KMS usage data on over 80,000 employees of a management consulting firm. Our approach infers the presence of identification and internalization from associations between actual system use behaviors by a focal individual and prior system use by a range of reference groups. Evidence of these kinds of associations between system use behaviors helps construct a more complete picture of social influence mechanisms, and is to our knowledge novel to the technology diffusion literature. Our results confirm the utility of this approach for understanding social influence effects and reveal a fine-grained pattern of influence across different social groups: we found strong support for bottom-up social influence across hierarchical levels, limited support for peer-level influence within levels, and no support for top-down influence.

The role of aggressions suffered by healthcare workers as predictors of burnout

Abstract: Aims and objectives. To examine the prevalence of aggression against healthcare professionals and to determine the possible impact that violent episodes have on healthcare professionals in terms of loss of enthusiasm and involvement towards work. The objective was to analyse the percentage of occupational assault against professionals' aggression in different types of healthcare services, differentiating between physical and verbal aggression as a possible variable in detecting burnout in doctors and nursing professionals. Background. Leiter and Maslach have explored a double process model of burnout not only based on exhaustion by overload, but also based on personal and organisational value conflicts (community, rewards or values). Moreover, Whittington has obtained conclusive results about the possible relationship between violence and burnout in mental health nurses. Design. A retrospective study was performed in three hospitals and 22 primary care centres in Spain (n = 1·826). Methods. Through different questionnaires, we have explored the relationship between aggression suffered by healthcare workers and burnout. Results. Eleven percent of respondents had been physically assaulted on at least one occasion, whilst 34·4% had suffered threats and intimidation on at least one occasion and 36·6% had been subjected to insults. Both forms of violence, physical and non-physical aggression, showed significant correlations with symptoms of burnout (emotional exhaustion, depersonalisation and inefficacy). Conclusions. The survey showed evidence of a double process: (1) by which excess workload helps predict burnout, and (2) by which a mismatch in the congruence of values, or interpersonal conflict, contributes in a meaningful way to each of the dimensions of burnout, adding overhead to the process of exhaustion-cynicism-lack of realisation. Relevance to clinical practice. Studies indicate that health professionals are some of the most exposed to disorders steaming from psychosocial risks and a high comorbidity: anxiety, depression, etc. There is a clear need for accurate instruments of evaluation to detect not only the burnout but also the areas that cause it. Professional exhaustion caused by aggression or other factors can reflect a deterioration in the healthcare relationship. Language: en

Organizational predictors and health consequences of changes in burnout: A 12-year cohort study

Abstract: Summary We investigated job burnout and job characteristics, including decision authority, skill discretion, predict-ability, andinformationflow,amongFinnishforestryworkers(N=4356) ina longitudinal study. Welinkedthese responses individually with data on the participants’ subsequent prescriptions for psychotropic drugsincludingantidepressants.Weaimtostudytheantecedentsofchangesinburnoutlevelsoverfouryearstimeand their health-related consequences in an eight-year follow-up. The results showed that inconsistencyamong the levels of the Maslach Burnout Inventory subscales (e. g., high scores in exhaustion and lowcynicism or vice versa) at baseline identified patterns that were prone to change in burnout four years later.Informationflow predicted the direction of this change for the exhaustion and cynicism aspects of burnout,whereas skill discretion and predictability did so for reduced professional efficacy. Change toward burnoutpredicted future risk of psychotropic drug use. It seems that adverse changes in burnout are influenced bypoor organizational resources, and change toward burnout is likely to elevate the risk of poor mental health.Copyright © 2012 John Wiley & Sons, Ltd.Keywords: burnout; health; longitudinal; change

Statistical guidelines for Apis mellifera research

Abstract: Summary In this article we provide guidelines on statistical design and analysis of data for all kinds of honey bee research. Guidelines and selection of different methods presented are, at least partly, based on experience. This article can be used: to identify the most suitable analysis for the type of data collected; to optimise one’s experimental design based on the experimental factors to be investigated, samples to be analysed, and the type of data produced; to determine how, where, and when to sample bees from colonies; or just to inspire. Also included are guidelines on presentation and reporting of data, as well as where to find help and which types of software could be useful.

The roles of unit leadership and nurse-physician collaboration on nursing turnover intention.

Abstract: Aim To report a study of the relationship between variables at the group and individual level with nurses' intention to leave their unit. Background Workplaces are collective environments where workers constantly interact with each other. The quality of working relationship employees develop at the unit-level influences both employee outcomes and unit performance by shaping employee attitudes. Design The study was a cross-sectional design with self-administered questionnaires. Methods A questionnaire including measures of leader–member exchange and nurse–physician collaboration analysed at group-level and affective commitment and turnover intention analysed at individual level, was administered individually to 1018 nurses in five Italian hospitals. Data were collected in 2009. Results A total of 832 nurses (81·7% response rate) completed questionnaires. The results showed that affective commitment at individual level completely mediated the relationship between leader–member exchange at group-level and nursing turnover intention. Furthermore, the cross-level interaction was significant: at individual level, the nurses with high levels of individual affective commitment towards their unit showed low levels of turnover intention and this relationship was stronger when the nurse–physician collaboration at group-level was high. Conclusion This study showed the importance for organizations to implement management practices that promote both high-quality nurse–supervisor and nurse–physician relationships, because they increase nurses' identification with their units. Individual affective commitment is an important quality for retaining a workforce and good nurses' relationship at group-level relationships with both supervisors and physicians are instrumental in developing identification with the work unit. Thus, the quality of relationship among staff members is an important factor in nurses' decision to leave.

Origin and evolution of Avalonia: evidence from U–Pb and Lu–Hf isotopes in zircon from the Mira terrane, Canada, and the Stavelot–Venn Massif, Belgium

Abstract: Laser ablation inductively coupled plasma mass spectrometry U–Pb and Lu–Hf isotope analyses of detrital zircon from Neoproterozoic–Cambrian clastic sedimentary rocks in the Mira terrane (Cape Breton Island, Nova Scotia, Canada; West Avalonia) and the Stavelot–Venn Massif (East Belgium; East Avalonia) support deposition on an originally coherent microcontinent. Crustal evolution trends defined by ϵHf (t) values varying with age reflect juvenile magma production in the source continent at 1.2–2.2 and 2.4–3.1 Ga. Mixing of juvenile and recycled crust in continental magmatic arcs is recognized at 0.5–0.72, 1.4–1.7, 1.8–2.2 and 2.4–2.7 Ga. These results concur with the crustal evolution in Amazonia, the likely parent craton. Crustal evolution in Avalonia is recorded in detrital and magmatic zircon from Neoproterozoic arcs (680–550 Ma). Positive ϵHf (t) values suggest juvenile input and mixing with recycled crust. Most negative ϵHf (t) values represent recycling of predominantly Mesoproterozoic underlying crust. Avalonian arc magmatism was followed by late Neoproterozoic–early Cambrian sedimentation in various belts in West Avalonia. These belts were juxtaposed by strike-slip during late early Cambrian deposition in a rift basin. The youngest detrital zircon population ( c . 517 Ma) probably represents synrift magmatism before break-up of Avalonia. Migmatization at 406 ± 2 Ma in a xenolith from the East Avalonian crust reflects post-collisional heating. Supplementary materials: Details of sample locations and analytical results are available at www.geolsoc.org.uk/SUP18641.

Effects of fluvalinate on honey bee learning, memory, responsiveness to sucrose, and survival.

Abstract: Contaminants can affect organisms' behaviour and, as a consequence, survival. Tau-fluvalinate (hereafter fluvalinate) is the active ingredient in a pesticide commonly used in North America to control Varroa destructor mites in honey bee (Apis mellifera) colonies. Fluvalinate's effects on honey bees are not well known. Honey bee cognitive and neural function can be assessed using the proboscis extension reflex (PER), which applies Pavlovian conditioning techniques. This study used PER to evaluate effects of fluvalinate on honey bee acquisition learning, (long-term) memory recall, responsiveness to sucrose, and mortality. We also evaluated how exclusion criteria for honey bees that did not exhibit PER during training and memory trials affected interpretation of results. Fluvalinate was administered both orally and dermally at high and low doses to mimic routes by which honey bees are exposed. We found negative effects of fluvalinate on honey bee learning, memory, responsiveness to sucrose, and survival, especially in high oral doses. We also found significant consequences to interpretation of results using different exclusion criteria. For example, almost 50% of individuals that failed to show evidence of learning subsequently showed evidence of memory. The latter results have important implications regarding traditional assessment of PER-based learning and memory; the former results suggest that evaluation of honey bee exposure to fluvalinate and attendant consequences warrants further investigation.

Integrating Information from Geolocators, Weather Radar, and Citizen Science to Uncover a Key Stopover Area of an Aerial Insectivore

Abstract: . Determining the distribution of stopover and overwintering areas of migratory animals is essential for understanding population dynamics and building predictive models. Tree Swallows (Tachycineta bicolor) are small songbirds that breed across North America. Data from Doppler weather radar and eBird indicate that Tree Swallow numbers increase throughout October and November in southeastern Louisiana, but then decrease during December. We thus hypothesized that southeastern Louisiana is a stopover area used by Tree Swallows during fall migration before they move to farther overwintering areas. We tested this hypothesis by attaching light-logging geolocators to Tree Swallows at five breeding sites spanning the species' breeding range from British Columbia to Nova Scotia, and then tracking their fall migration routes, stopover sites, and wintering locations. Of 38 individuals that returned in the following breeding season, 11 birds from three breeding sites (Saskatchewan, Wisconsin, and Ontario) use...

Evaluating sustainability of fisheries bycatch mortality for marine megafauna: a review of conservation reference points for data-limited populations

Abstract: Fisheries bycatch threatens populations of marine megafauna such as marine mammals, turtles, seabirds, sharks and rays, but fisheries impacts on non-target populations are often difficult to assess due to factors such as data limitation, poorly defined management objectives and lack of quantitative bycatch reduction targets. Limit reference points can be used to address these issues and thereby facilitate adoption and implementation of mitigation efforts. Reference points based on catch data and life history analysis can identify sustainability limits for bycatch with respect to defined population goals even when data are quite limited. This can expedite assessments for large numbers of species and enable prioritization of management actions based on mitigation urgency and efficacy. This paper reviews limit reference point estimators for marine megafauna bycatch, with the aim of highlighting their utility in fisheries management and promoting best practices for use. Different estimators share a common basic structure that can be flexibly applied to different contexts depending on species life history and available data types. Information on demographic vital rates and abundance is required; of these, abundance is the most data-dependent and thus most limiting factor for application. There are different approaches for handling management risk stemming from uncertainty in reference point and bycatch estimates. Risk tolerance can be incorporated explicitly into the reference point estimator itself, or probability distributions may be used to describe uncertainties in bycatch and reference point estimates, and risk tolerance may guide how those are factored into the management process. Either approach requires simulation-based performance testing such as management strategy evaluation to ensure that management objectives can be achieved. Factoring potential sources of bias into such evaluations is critical. This paper reviews the technical, operational, and political challenges to widespread application of reference points for management of marine megafauna bycatch, while emphasizing the importance of developing assessment frameworks that can facilitate sustainable fishing practices.

Feeding ecology of Atlantic sturgeon, Acipenser oxyrinchus oxyrinchus Mitchill, 1815 on the infauna of intertidal mudflats of Minas Basin, Bay of Fundy

Abstract: Summary A large feeding aggregation of Atlantic sturgeon occupies the inner Bay of Fundy during summer, presumably to forage on the intertidal mudflats. The feeding habits of Atlantic sturgeon were examined during summer 2011 in Minas Basin as description of diet is important for identifying critical foraging areas. Atlantic sturgeon demonstrated an overall preference for sandy tube-dwelling polychaetes (Index of Relative Importance (IRI) = 99.7%). Major prey taxa included Maldanidae (Clymanella sp., 52.5%) and Spionidae, primarily the species Spiophanes bombyx (41.6%). Other prey items consumed included Phyllodocidae (Eteone sp., 2.1%), Nephtyidae (2.2%), Nereididae (0.7%), and Glyceridae including Glycera dibranchiata (0.6%). Seventeen additional taxa were identified in trace amounts (mean IRI = 0.02%), including Corophidae and Mysidae. There was no significant difference in the number of prey items consumed and the fork length of the fish. Analysis of gut fullness with respect to tidal state indicated no significant difference between gut fullness on the flood or ebb tide. An overall preference for sandy tube-dwelling polychaetes may indicate that particular areas of the Minas Basin intertidal region are more important than others to these foraging fish. Considerable baitworm harvesting occurs during summer months in Minas Basin and could potentially create impacts with sturgeon consumers, both directly through competition for prey items and indirectly through change in sediment and benthic community composition.

Use of GIS and high resolution LiDAR in salt marsh restoration site suitability assessments in the upper Bay of Fundy, Canada

Abstract: Salt marshes exhibit striking vegetation zonation corresponding to spatially variable elevation gradients which dictate their frequency of inundation by the tides. The salt marshes in the upper Bay of Fundy, a dynamic hypertidal system, are of considerable interest due to increasing recognition of salt marsh ecosystem values and the extent of prior conversion of salt marshes to agricultural lands, much of which are no longer in use. To determine the suitability of two potential restoration sites at Beausejour Marsh in New Brunswick, Canada, geomatics technologies and techniques were used to assess vegetation and elevation patterns in an adjacent reference salt marsh and the proposed restoration sites. Light detection and ranging digital elevation models (DEMs) were created for the reference marsh and the restoration sites in both the spring (leaf-off) and late summer (leaf-on, maximum biomass) periods. Aerial photographs and Quickbird multispectral imagery were used to visually interpret vegetation zones on the reference marsh and were field validated using vegetation characteristics from quadrats referenced with differential GPS. Elevation limits of the salt marsh vegetation zones were extracted from the DEM of the reference marsh and applied to the DEM of the restoration sites to determine the percentage area of each site that would be immediately suitable for new salt marsh growth. Of the two restoration sites assessed, one had experienced significant subsidence since dyking; only about 40 % of the site area was determined to be of sufficient elevation for immediate vegetation colonization. The second site, while more than 88 % suitable, would require the installation of a large dyke on the landward side of the restoration site to prevent flooding of adjacent lands. This study provides essential high resolution elevation and vegetation zonation data for use in restoration site assessments, and highlights the usefulness of applied geomatics in the salt marsh restoration planning process.

Improvisation as a Curricular Metaphor: Imagining Education for a Rural Creative Class

Abstract: Rural communities contain a largely unacknowledged innovative capacity founded on improvisational traditions. These traditions may be rooted in work practices in agriculture and other rurally-based productive activities but today they have expanded into other lifeworld locations, particularly virtual spaces that accelerate time-space compression. I make the case here that in the networked world of high modernity or postmodernity, both the nature of rurality and the potential of rural education need to be theorized differently. I begin with a critique of Richard Florida’s metrocentric idea of the creative class, then move to reconceptualizing rurality as a real and imagined space, and conclude by analyzing a film and video project in an Atlantic Canadian school that used improvisation in literacy curriculum work. I argue that improvisation is a potentially productive metaphor for curriculum, one which draws on rural traditions and local funds of knowledge while at the same time incorporating a productive, forward-looking engagement with new technologies.

Synthetic prodigiosenes and the influence of C-ring substitution on DNA cleavage, transmembrane chloride transport and basicity.

Abstract: Analogues of the tripyrrolic natural product prodigiosin bearing an additional methyl and a carbonyl group at the C-ring were synthesised and evaluated. In vitro anticancer activity screening (NCI) and the study of modes of action (copper-mediated cleavage of double-stranded DNA and transmembrane transport of chloride anions) showed that the presence of the methyl group is not detrimental to activity. Furthermore, although the presence of an ester conjugated to the prodigiosene C-ring seems to decrease both pKa and chloride transport efficiency compared to the natural product, these analogues still exhibit a high rate of chloride transport. All analogues exhibit good in vitro anticancer activity and reduced toxicity compared to the natural product: compare an acute systemic toxicity of 100 mg kg−1 in mice vs. 4 mg kg−1 for prodigiosin, pointing towards a larger therapeutic window than for the natural product.

Treatment of 2,4-D, mecoprop, and dicamba using membrane bioreactor technology

Abstract: Phenoxyacetic and benzoic acid herbicides are widely used agricultural, commercial, and domestic pesticides. As a result of high water solubility, mobility, and persistence, 2,4-dichlorophenoxyacetic acid (2,4-D), methylchlorophenoxypropionic acid (mecoprop), and 3,6-dichloro-2-methoxybenzoic acid (dicamba) have been detected in surface and waste waters across Canada. As current municipal wastewater treatment plants do not specifically address chronic, trace levels of contaminants like pesticides, an urgent need exists for an efficient, environmentally friendly means of breaking down these toxic herbicides. A commercially available herbicide mix, WeedEx, containing 2,4-D, mecoprop, and dicamba, was subjected to treatment using membrane bioreactor (MBR) technology. The three herbicides, in simulated wastewater with a chemical oxygen demand of 745 mg/L, were introduced to the MBR at concentrations ranging from 300 μg/L to 3.5 mg/L. Herbicides and biodegradation products were extracted from MBR effluent using solid-phase extraction followed by detection using high-performance liquid chromatography coupled with mass spectrometry. 2,4-D was reduced by more than 99.0 % within 12 days. Mecoprop and dicamba were more persistent and reduced by 69.0 and 75.4 %, respectively, after 112 days of treatment. Half-lives of 2,4-D, mecoprop and dicamba during the treatment were determined to be 1.9, 10.5, and 28.3 days, respectively. Important water quality parameters of the effluent such as dissolved oxygen, pH, ammonia, chemical oxygen demand, etc. were measured daily. MBR was demonstrated to be an environmentally friendly, compact, and efficient method for the treatment of toxic phenoxyacetic and benzoic acid herbicides.