New studies in aromatic chloromethylation

Chloromethylation reactions of anisole, cumene and trifluoromethylbenzene have been examined using the reagents formaldehyde and hydrogen chloride, in the presence of an extensive range of catalysts. Reaction conditions and choice of catalyst have been optimised to obtain a high ratio of chloromethylated product: diarylmethane product. For anisole this requires the use of titanium tetrachloride as catalyst at O-5ºC; for cumene, zinc chloride as catalyst at 42-48ºC gives the best results. Trifluoromethylbenzene could not be chloromethylated using the HCI/CH(_2)O/ catalyst system. Other alkoxybenzene substrates and chloromethylating reagents have been briefly studied

Techniques of public education employed with community groups by the Massachusetts Society for Mental Hygiene

Thesis (M.S.)--Boston Universit

Logistic Knowledge Tracing: A Constrained Framework for Learner Modeling

Adaptive learning technology solutions often use a learner model to trace learning and make pedagogical decisions. The present research introduces a formalized methodology for specifying learner models, Logistic Knowledge Tracing (LKT), that consolidates many extant learner modeling methods. The strength of LKT is the specification of a symbolic notation system for alternative logistic regression models that is powerful enough to specify many extant models in the literature and many new models. To demonstrate the generality of LKT, we fit 12 models, some variants of well-known models and some newly devised, to 6 learning technology datasets. The results indicated that no single learner model was best in all cases, further justifying a broad approach that considers multiple learner model features and the learning context. The models presented here avoid student-level fixed parameters to increase generalizability. We also introduce features to stand in for these intercepts. We argue that to be maximally applicable, a learner model needs to adapt to student differences, rather than needing to be pre-parameterized with the level of each student's ability

The IGCP 509 Database System: Design and application of a tool to capture and illustrate litho- and chrono-stratigraphic information for Palaeoproterozoic tectonic domains, large igneous provinces and ore deposits; with examples from southern Africa

The IGCP 509 project is collating global information for the Palaeoproterozoic era through the activities of numerous international collaborators. A database system (StratDB) and web interface has been designed to facilitate this process with links to an existing geochronology database (DateView). As a result, all information captured will remain available in a digital format for future researchers. The philosophy and design of the database and some of the outputs available from it are described. One of the principal features of the system is that it facilitates the construction of time-space correlation charts using an innovative application of GIS technology to nongeographic information, which permits users to query a variety of attribute information associated with lithostratigraphic units, metamorphic and deformation episodes associated with user-selected tectonic domains, large igneous provinces and major ore deposits. In the process, much of the manual labour normally associated with the construction of such charts in standard graphical or drafting packages is avoided.Associations between units, deformation, metamorphism, large igneous provinces and ore deposits may become more apparent once linked information is available for querying and investigation. Geochronological information from the DateView database may also be linked to entities stored in StratDB. GIS maps may be linked to the attribute informationin StratDB and DateView to construct a variety of time-slice maps or palaeogeographic reconstructions with the same symbology as is used in the time-space correlation charts. This database system will facilitate the dissemination of lithostratigraphic information for many countries to a broader community and will help non-specialists to easily view information for various Palaeoproterozoic tectonic domains. The system is illustrated using a preliminary compilation of information for the Palaeoproterozoic of southern Africa. The correlation charts and time-slice maps provide insights to the geological evolution of this region which emphasize some aspects and correlations which have not previously been extensively considered; for instance, possible correlation of units in the central and western zones of the Limpopo Belt (South Africa, Zimbabwe and Botswana) with the Magondi Belt of Zimbabwe and its extension into northern Botswana

Cross-Modal Attention Influences Auditory Contrast Sensitivity: Decreasing Visual Load Improves Auditory Thresholds for Amplitude- and Frequency-Modulated Sounds

We used a cross-modal dual task to examine how changing visual-task demands influenced auditory processing, namely auditory thresholds for amplitude- and frequency-modulated sounds. Observers had to attend to two consecutive intervals of sounds and report which interval contained the auditory stimulus that was modulated in amplitude (Experiment 1) or frequency (Experiment 2). During auditory-stimulus presentation, observers simultaneously attended to a rapid sequential visual presentation—two consecutive intervals of streams of visual letters—and had to report which interval contained a particular color (low load, demanding less attentional resources) or, in separate blocks of trials, which interval contained more of a target letter (high load, demanding more attentional resources). We hypothesized that if attention is a shared resource across vision and audition, an easier visual task should free up more attentional resources for auditory processing on an unrelated task, hence improving auditory thresholds. Auditory detection thresholds were lower—that is, auditory sensitivity was improved—for both amplitude- and frequency-modulated sounds when observers engaged in a less demanding (compared to a more demanding) visual task. In accord with previous work, our findings suggest that visual-task demands can influence the processing of auditory information on an unrelated concurrent task, providing support for shared attentional resources. More importantly, our results suggest that attending to information in a different modality, cross-modal attention, can influence basic auditory contrast sensitivity functions, highlighting potential similarities between basic mechanisms for visual and auditory attention

The Financial Return from Measuring Impact

In conservation, as in most other subjects, there is a division of expenditure into problem identification, solution testing, and practice. However, research concentrates on problem identification rather than solution testing. We calculate the return on the investment of research (a PhD thesis) examining the effectiveness of conservation interventions for birds of prey in three European countries. We show that the economic return from investing in a PhD thesis could be substantial, in the order of hundreds of thousands euros over 10 years or a return on investment of between 292% and 326% over that period. We derived the values of return on investment by first setting a common biological target (the total number of raptor fledglings produced per year). We then compared overall costs in achieving such target via the wide implementation of the results from the thesis (i.e., allocating resources to the most effective intervention) versus a business as usual scenario. We identify other theses that also show considerable benefits in improving effectiveness. We suggest that further research examining effectiveness would be cost-effective in improving practice.Peer reviewe

Scenarios of habitat management options to reduce predator impacts on nesting waders

1. Wetland ecosystems throughout the world are threatened by drainage and intensification of agriculture. Consequently, many wetland species of conservation concern are now restricted to fewer and smaller sites, and maintaining these species often requires intensive habitat management.  2. In Western Europe, breeding wader populations have declined severely as a result of wetland degradation, but very high levels of predation on eggs and chicks are now preventing population recovery. Wet grassland management for breeding waders has focussed on providing suitable nesting habitats, but the potential for management of landscape features to influence predation rates is largely unknown.  3. Using a 7-year study of breeding lapwing, Vanellus vanellus, and redshank, Tringa totanus, we first identify features that influence nest predation, and then use this information to compare the magnitude of change in nest predation rates that could potentially result from future landscape management scenarios.  4. As lapwing nest predation rates are higher (a) in fields further from patches of tall vegetation, (b) close (<50 m) to field edges in wet fields, (c) further from field edges in dry fields and (d) in areas of low lapwing nesting density, we modelled a series of realistic scenarios in which the area of tall vegetation and the extent and distribution of surface water were varied across the reserve, in order to quantify the magnitude of change in nest predation rate that could potentially have been achieved through management.  5. Modelled scenarios of changes in surface water and area of tall vegetation indicated that reduced surface flooding combined with removal of tall vegetation could result in significant increases in lapwing nest predation rates in areas with low nesting densities and nests in field centres. By contrast a ~20% reduction in nest predation, corresponding to ~100 more chicks hatching per year, is predicted in scenarios with expansion of tall vegetation in areas with high lapwing nest density and nests close to field edges.  6. Synthesis and applications: These management scenarios suggest that, for breeding waders in wet grassland landscapes, creating areas of tall vegetation and concentrating surface flooding (to encourage high nesting densities and influence nesting distribution) can potentially help to reduce the unsustainably high levels of nest predation that are preventing population recovery

Infaunalization and resource partitioning during the Mesozoic marine revolution

Infaunalization has been regarded as representing a response to increased predation pressures and is therefore central to the Mesozoic marine revolution, which gives pre-eminence to the role that enemy-directed evolution has played as a driving force of biotic change. Our ichnologic compilation from 39 Middle Triassic to Late Jurassic shallow-marine siliciclastic units allows us to evaluate the vertical partitioning of the infaunal ecospace through the application of the ichnoguild concept. This study shows that infaunal communities experienced a marked increase in ecospace utilization during the Early Jurassic, reaching a plateau during the rest of the Jurassic. This trend is expressed by an increase in the maximum number of ichnoguilds per community and per tier and in the number of ichnotaxa per ichnoguild. This pattern shows important partitioning of the infaunal ecospace into a series of tiers and that several organisms were able to exploit the same resources available at discrete sediment zones below the sea bottom. The increase in the maximum number of ichnoguilds per community and per tier suggests that niche partitioning was a key factor in a more efficient use of the infaunal ecospace and in driving alpha diversity. However, the increase in the number of ichnotaxa per ichnoguild indicates that ichnoguilds were packed with organisms exploiting similar resources, arguing against the role of competitive exclusion in structuring communities. Because several episodes of predation increase took place during the Mesozoic, an unequivocal link between predation pressures and infaunalization cannot be demonstrated empirically.Fil: Buatois, Luis Alberto. University of Saskatchewan; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mángano, M. Gabriela. University of Saskatchewan; CanadáFil: Desai, Bhawanisingh. Pandit Deendayal Energy University; IndiaFil: Carmona, Noelia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Burns, Fiona. Firmground; AustraliaFil: Meek, Dean. University of Saskatchewan; CanadáFil: Eglington, Bruce. University of Saskatchewan; Canad