Conference Models to Bridge Micro and Macro Studies of Science

We propose using community-centered analyses and agent-based models of scientific gatherings such as conferences, symposia and workshops as a way to understand how scientific practices evolve and transition between local, community, and systems levels in science. We suggest using robotics as a case study of global, cross-cultural, interdisciplinary scientific practice. What is needed is a set of modeling frameworks for simulating both the internal and population dynamics of scientific gatherings. In this paper we make the case for conference models as a mid-level unit of analysis that can advance the ways scientists and citizens design systems for transferring and producing knowledge.Science of Science, Conferences, Community-Based Complex Models, Group Size, Methodology

Lifelong exposure to air pollution and cognitive development in young children: the UK Millennium Cohort Study

Background. Evidence about the impact of air pollution on cognitive development of children has been growing but remains inconclusive. Objectives. To investigate the association of air pollution exposure and the cognitive development of children in the UK Millennium Cohort Study. Methods. Longitudinal study of a nationally representative sample of 13,058-14,614 singleton births, 2000-2002, analysed at age 3, 5 and 7 years for associations between exposure from birth to selected air pollutants and cognitive scores for: School Readiness, Naming Vocabulary (age 3 and 5), Picture Similarity, Pattern Construction (age 5 and 7), Number Skills and Word Reading. Multivariable regression models took account of design stratum, clustering and sampling and attrition weights with adjustment for major risk factors, including age, gender, ethnicity, region, household income, parents' education, language, siblings and second-hand tobacco smoke. Results: In fully adjusted models, no associations were observed between pollutant exposures and cognitive scores at age 3. At age 5, particulate matter (PM2.5, PM10), nitrogen dioxide (NO2), sulphur dioxide (SO2) and carbon monoxide (CO) were associated with lower scores for Naming Vocabulary but no other outcome except for SO2 and Picture Similarity. At age 7, PM2.5, PM10 and NO2 were associated with lower scores for Pattern Construction, SO2 with lower Number Skills and SO2 and ozone with poorer Word Reading scores, but PM2.5, PM10 and NO2 were associated with higher Word Reading scores. Adverse effects of air pollutants represented a deficit of up to around 4 percentile points in Naming Vocabulary at age 5 for an interquartile range increase in pollutant concentration, which is smaller than the impact of various social determinants of cognitive development. Conclusions: In a study of multiple pollutants and outcomes, we found mixed evidence from this UK-wide cohort study for association between lifetime exposure to neighbourhood air pollutants and cognitive development to age 7 years

Host Based Intrusion Detection for VANETs: A statistical approach to Rogue Node Detection

In this paper, an intrusion detection system (IDS) for vehicular ad hoc networks (VANETs) is proposed and evaluated. The IDS is evaluated by simulation in the presence of rogue nodes (RNs) that can launch different attacks. The proposed IDS is capable of detecting a false information attack using statistical techniques effectively and can also detect other types of attacks. First, the theory and implementation of the VANET model that is used to train the IDS is discussed. Then, an extensive simulation and analysis of our model under different traffic conditions is conducted to identify the effects of these parameters in VANETs. In addition, the extensive data gathered in the simulations are presented using graphical and statistical techniques. Moreover, RNs are introduced in the network, and an algorithm is presented to detect these RNs. Finally, we evaluate our system and observe that the proposed application-layer IDS based on a cooperative information exchange mechanism is better for dynamic and fast-moving networks such as VANETs, as compared with other techniques available

Detection of Endophyte Mycotoxins by Service Laboratories: Providing Answers for Safe Feed

. A global network of service laboratories exists to test livestock feed materials (typically grass hay and pellets) for ergovaline, ergot alkaloids and lolitrem B to ensure ‘safe feeds’ are being given to livestock. These compounds are mycotoxins produced by endophytic fungi that naturally reside in feed material. They have been purposely bred into grass species, as they enhance the plant’s survival from drought and insect predation. Unfortunately, ergovaline and other ergot alkaloids also cause vasoconstrictive effects and reproductive difficulties in livestock, resulting in a $1 million annual loss in production for the cattle industry in the USA alone. Lolitrem B is a neurotoxicant that causes a syndrome known as ‘ryegrass staggers,’ which involves a tremoring response in the animal. Clients of these service laboratories include hay farmers who want to be confident that the product they are selling is safe to feed to livestock; veterinarians who are trying to rule out causes of disease in clinical cases; individuals wanting to check personal feed sources; and researchers investigating innovative solutions to these feed contaminants. Each year, approximately 33,000 containers of hay are shipped overseas from the USA, including Pacific Rim and Middle Eastern countries, bringing in an estimated$130 million annually. If the importing country requires it, the material in these containers must be tested for the appropriate mycotoxin(s) and have a certificate stating that the level found was below the established threshold of toxicity. Discussion of sample submission, analysis and result receipt will be compared amongst international laboratories known to perform analyses for these mycotoxins

Assessing heat vulnerability in London care settings: case studies of adaptation to climate change

This pilot study aims at testing methods to assess heat vulnerability in London care homes and develop overheating reduction strategies to mitigate temperature exposure and the associated negative health impacts under the warming climate, with a view to scaling up the project on a national scale. It undertakes feasibility work to identify possible causes of overheating across a range of care home types and evaluate the current and future potential of indicative passive solutions. The summertime thermal environments of five case study care homes were monitored and their physical, technical and occupancy profiles were established through surveys. The data was inputed in the EnergyPlus V8.9 dynamic thermal simulations via the DesignBuilder Graphical User Interface. Future overheating risks and their reduction potential through the use of passive strategies were tested under a set of representative climate change scenarios, during a five-day heatwave period. The dynamic thermal simulation analysis indicated that older buildings with higher heat loss and thermal mass capacities are likely to benefit more from the application of high albedo materials rather than external shading methods, whereas newer and highly insulated buildings seem to benefit more from higher ventilation rates and appropriate external shading systems. Night ventilation emerged as the single most impactful passive technique for all building types. This feasibility work has developed novel methods, knowledge and insights that will be helpful in understanding how to enable care settings in the UK to become resilient to rising heat stress. This is one of the first systematic attempts to build a set of dynamic thermal models of care homes in the UK

Indoor environmental quality trade-offs due to summertime natural ventilation in London care homes

We evaluate current and future summertime temperature and indoor air quality (IAQ) in two London care homes, occupied by seniors. We further examine the effect of natural ventilation, aiming to identify strategies that can maintain temperature, CO2 and key pollutants (PM2.5, NO2) within acceptable ranges. Data come from simulations in DesignBuilder. Results show a higher risk of overheating in the newer care home, with 85% of hourly outputs exceeding 26°C. In addition, bedrooms are much warmer than lounges in both homes, with averages expected to reach 32-35°C by 2050. In terms of IAQ, 65% of PM2.5 and NO2 hourly outputs are within range; however, without any ventilation, the high CO2 levels are expected to rise by 70-130ppm in 2050, especially in bedrooms of the newer home. Results further indicate that natural ventilation can substantially reduce temperature and CO2, but at the same time it may increase PM2.5 and NO2 coming from outdoors. Yet, these trade-offs can be reduced through a careful ventilation strategy that considers building-specific characteristics, as well as time of day and duration. Findings suggest a need to focus on the interdependencies among indoor environmental quality outputs and highlight the value of inexpensive and sustainable passive ventilation

Frequency dispersion reduction and bond conversion on n-type GaAs by in situ surface oxide removal and passivation

The method of surface preparation on n-type GaAs, even with the presence of an amorphous-Si interfacial passivation layer, is shown to be a critical step in the removal of accumulation capacitance frequency dispersion. In situ deposition and analysis techniques were used to study different surface preparations, including NH4OH, Si-flux, and atomic hydrogen exposures, as well as Si passivation depositions prior to in situ atomic layer deposition of Al2O3. As–O bonding was removed and a bond conversion process with Si deposition is observed. The accumulation capacitance frequency dispersion was removed only when a Si interlayer and a specific surface clean were combined

Assessing the Current and Future Risk of Overheating in London’s Care Homes: The Effect of Passive Ventilation

The warming climate causes adverse effects on thermal comfort and health, especially for vulnerable older adults. This study assesses the current and future risk of summertime overheating in London’s care homes and explores the potential of passive ventilation on reducing these risks. Analysis is based on temperature monitoring of two care settings and on thermal simulation models of future conditions with and without passive ventilation strategies. Results show high overheating exposures for both care homes, with temperatures averaging 31-35 0C by 2050. Passive ventilation can substantially reduce these exposures, but a successful approach depends on time of day, duration and window characteristics. Dynamic window opening based on lower outdoor temperatures and indoor temperature exceedance of 22 0C is the most beneficial approach for both settings now and in the future. The study demonstrates the effectiveness of affordable building adaptations for reducing heat stress in senior care homes

GaAs interfacial self-cleaning by atomic layer deposition

The reduction and removal of surface oxides from GaAs substrates by atomic layer deposition (ALD) of Al2O3 and HfO2 are studied using in situ monochromatic x-ray photoelectron spectroscopy. Using the combination of in situ deposition and analysis techniques, the interfacial "self-cleaning" is shown to be oxidation state dependent as well as metal organic precursor dependent. Thermodynamics, charge balance, and oxygen coordination drive the removal of certain species of surface oxides while allowing others to remain. These factors suggest proper selection of surface treatments and ALD precursors can result in selective interfacial bonding arrangements