The effect of feedback and recollection rejection instructions on the development of memory monitoring and accuracy.

Recollection rejection (a form of memory monitoring) involves rejecting false details on the basis of remembering true details (recall to reject), thereby increasing memory accuracy. This study examined how recollection rejection instructions and feedback affect memory accuracy and false recognition in 5-year-olds, 6- and 7-year-olds, 8- and 9-year-olds, and adults. Participants (N = 336) completed three study-test phases. Instructions and item-level feedback were manipulated during the first two phases, with the third phase including a test containing no instructions or feedback to evaluate learning effects. As predicted, in the younger children, as compared with the older children and adults, we found reduced accuracy scores (hits to studied items minus false alarms to related lures), reduced recollection rejection to related lures, and increased false recognition scores. We also found that, in the third phase, prior feedback reduced false recognition scores, potentially by improving monitoring, and typical developmental differences in false recognition were eliminated. However, there were mixed findings of instructions and feedback, and in some conditions these interventions harmed memory. These findings provide initial evidence that combining instructions and feedback with repeated task practice may improve monitoring effectiveness, but additional work is needed on how these factors improve and sometimes harm performance in young children.

Effects of structural modification of (alkyldiene-imidazolium bromide)-based gemini monomers on the formation of the lyotropic bicontinuous cubic phase.

Seven homologues of an amphiphilic gemini monomer were synthesized and screened for the ability to form a bicontinuous cubic (Q) lyotropic liquid crystal phase. Four of these homologues form a Q phase with glycerol or water that can be cross-linked with retention of the nanoporous structure, with one exhibiting a well-ordered Q phase with a wider phase window than the parent monomer.

Children's Use of Memory Editing Strategies to Reject Source Misinformation.

This is the first reported study of children's use of two metacognitive strategies, recollection rejection and diagnostic monitoring, to reject misinformation. Recollection rejection involves the retrieval of details that disqualify an event, whereas diagnostic monitoring involves the failure to retrieve expected details. First (n = 56, age 7 years) and third graders (n = 52, age 9 years) witnessed a staged classroom interaction involving common and bizarre accidents, were presented with misinformation about the source of these events, and took a memory test. Both age groups used recollection rejection, but third graders were more effective. There was little evidence that diagnostic monitoring influenced responses for bizarre events, potentially because these events were not sufficiently bizarre in the context of the stereotype induction.

Effects of feedback and test practice on recollection and retrieval monitoring: comparing first graders, third graders, and adults.

We tested the effects of repeated testing and feedback on recollection accuracy in first graders, third graders, and adults. All participants studied a list of words and pictures, and then took three recollection tests, with each test probing different words and pictures from the earlier study phase. On the first and third tests no feedback was given, whereas on the second test, some subjects received item-level feedback throughout the recollection test. Recollection confusion scores declined across successive tests in all age groups. However, explicit feedback did not improve recollection accuracy or reduce recollection confusions in any age group. We also found that all age groups were able to use picture recollections in a disqualifying monitoring strategy without task experience or feedback. As a whole, these findings suggest that children and adults can use some aspects of retrieval monitoring without feedback or practice, whereas other aspects of retrieval monitoring can benefit from test practice in children and adults. We discuss the potential roles of metacognitive learning and unintended social feedback on these test practice effects.

Benchmarking novel approaches for modelling species range dynamics.

Increasing biodiversity loss due to climate change is one of the most vital challenges of the 21st century. To anticipate and mitigate biodiversity loss, models are needed that reliably project species' range dynamics and extinction risks. Recently, several new approaches to model range dynamics have been developed to supplement correlative species distribution models (SDMs), but applications clearly lag behind model development. Indeed, no comparative analysis has been performed to evaluate their performance. Here, we build on process-based, simulated data for benchmarking five range (dynamic) models of varying complexity including classical SDMs, SDMs coupled with simple dispersal or more complex population dynamic models (SDM hybrids), and a hierarchical Bayesian process-based dynamic range model (DRM). We specifically test the effects of demographic and community processes on model predictive performance. Under current climate, DRMs performed best, although only marginally. Under climate change, predictive performance varied considerably, with no clear winners. Yet, all range dynamic models improved predictions under climate change substantially compared to purely correlative SDMs, and the population dynamic models also predicted reasonable extinction risks for most scenarios. When benchmarking data were simulated with more complex demographic and community processes, simple SDM hybrids including only dispersal often proved most reliable. Finally, we found that structural decisions during model building can have great impact on model accuracy, but prior system knowledge on important processes can reduce these uncertainties considerably. Our results reassure the clear merit in using dynamic approaches for modelling species' response to climate change but also emphasize several needs for further model and data improvement. We propose and discuss perspectives for improving range projections through combination of multiple models and for making these approaches operational for large numbers of species.

Does probability of occurrence relate to population dynamics?

Hutchinson defined species' realized niche as the set of environmental conditions in which populations can persist in the presence of competitors. In terms of demography, the realized niche corresponds to the environments where the intrinsic growth rate (r) of populations is positive. Observed species occurrences should reflect the realized niche when additional processes like dispersal and local extinction lags do not have overwhelming effects. Despite the foundational nature of these ideas, quantitative assessments of the relationship between range-wide demographic performance and occurrence probability have not been made. This assessment is needed both to improve our conceptual understanding of species' niches and ranges and to develop reliable mechanistic models of species geographic distributions that incorporate demography and species interactions. The objective of this study is to analyse how demographic parameters (intrinsic growth rate r and carrying capacity K) and population density (N) relate to occurrence probability (Pocc ). We hypothesized that these relationships vary with species' competitive ability. Demographic parameters, density, and occurrence probability were estimated for 108 tree species from four temperate forest inventory surveys (Québec, Western US, France and Switzerland). We used published information of shade tolerance as indicators of light competition strategy, assuming that high tolerance denotes high competitive capacity in stable forest environments. Interestingly, relationships between demographic parameters and occurrence probability did not vary substantially across degrees of shade tolerance and regions. Although they were influenced by the uncertainty in the estimation of the demographic parameters, we found that r was generally negatively correlated with Pocc , while N, and for most regions K, was generally positively correlated with Pocc . Thus, in temperate forest trees the regions of highest occurrence probability are those with high densities but slow intrinsic population growth rates. The uncertain relationships between demography and occurrence probability suggests caution when linking species distribution and demographic models.

Search efforts and face recognition: the role of expectations of encounter and within-person variability in prospective person memory.

People perform poorly at sighting missing and wanted persons in simulated searches due to attention and face recognition failures. We manipulated participants' expectations of encountering a target person and the within-person variability of the targets' photographs studied in a laboratory-based and a field-based prospective person memory task. We hypothesized that within-person variability and expectations of encounter would impact prospective person memory performance, and that expectations would interact with within-person variability to mitigate the effect of variability. Surprisingly, low within-person variability resulted in better performance on the search task than high within-person variability in Experiment one possibly due to the study-test images being rated as more similar in the low variability condition. We found the expected effect of high variability producing more hits for the target whose study-test images were equally similar across variability conditions. There was no effect of variability in Experiment two. Expectations affected performance only in the field-based study (Experiment two), possibly because performance is typically poor in field-based studies. Our research demonstrates some nuance to the effect of within-person variability on search performance and extends existing research demonstrating expectations affect search performance.

The effect of pre-event instructions on eyewitness identification.

Research on eyewitness identification often involves exposing participants to a simulated crime and later testing memory using a lineup. We conducted a systematic review showing that pre-event instructions, instructions given before event exposure, are rarely reported and those that are reported vary in the extent to which they warn participants about the nature of the event or tasks. At odds with the experience of actual witnesses, some studies use pre-event instructions explicitly warning participants of the upcoming crime and lineup task. Both the basic and applied literature provide reason to believe that pre-event instructions may affect eyewitness identification performance. In the current experiment, we tested the impact of pre-event instructions on lineup identification decisions and confidence. Participants received non-specific pre-event instructions (i.e., "watch this video") or eyewitness pre-event instructions (i.e., "watch this crime video, you'll complete a lineup later") and completed a culprit-absent or -present lineup. We found no support for the hypothesis that participants who receive eyewitness pre-event instructions have higher discriminability than participants who receive non-specific pre-event instructions. Additionally, confidence-accuracy calibration was not significantly different between conditions. However, participants in the eyewitness condition were more likely to see the event as a crime and to make an identification than participants in the non-specific condition. Implications for conducting and interpreting eyewitness identification research and the basic research on instructions and attention are discussed.

Prior experience with target encounter affects attention allocation and prospective memory performance.

We examined how prior experience encountering targets affected attention allocation and event-based prospective memory. Participants performed four color match task blocks with a difficult, but specified prospective memory task (Experiment 1) or an easier, but unspecified prospective memory task (Experiment 2). Participants were instructed to search for targets on each block. Participants in the prior experience condition saw targets on each block, participants in the no prior experience condition only saw targets on the fourth block, and, in Experiment 2, participants in the mixed prior experience condition encountered some of the targets on the first three blocks, and saw all the targets on the fourth block. In Experiment 1, participants in the no prior experience condition were less accurate at recognizing targets and quicker to respond on ongoing task trials than participants in the prior experience condition. In Experiment 2, we replicated the effect of prior experience on target accuracy, but there was no effect on ongoing trial response time. The mixed experience condition did not vary from the other conditions on either dependent variable, but their target accuracy varied in accordance with their experience. These findings demonstrate that prospective memory performance is influenced by experience with related tasks, thus extending our understanding of the dynamic nature of search efforts across related prospective memory tasks. This research has implications for understanding prospective memory in applied settings where targets do not reliably occur such as baggage screenings and missing person searches.

Can spatial isolation help predict dispersal-limited sites for native species restoration?

When the distribution of species is limited by propagule supply, new populations may be initiated by seed addition, but identifying suitable sites for efficiently targeted seed addition remains a major challenge for restoration. In addition to the biotic or abiotic variables typically used in species distribution models, spatial isolation from conspecifics could help predict the suitability of unoccupied sites. Site suitability might be expected to increase with spatial isolation after other factors are accounted for, since isolation increases the chance that a site is unoccupied only because of propagule limitation. For two native annual forbs in Californian grasslands, we combined experimental seeding and niche modeling to ask whether suitability of unoccupied sites could be predicted by spatial variables (either distances from, or densities of, conspecific populations), either by themselves or in combination with niche models. We also asked whether experimental tests of these predictions held up not only in the short term (one year), but also in the longer term (three years). For Lasthenia californica, seed additions were only successful relatively near existing populations. For Lupinus nanus, seeding success was low and was positively related to the number of conspecifics within 1 km. For both species, a few previously unoccupied sites remained occupied three years after seeding, but this subset was not predictable based on either spatial or niche variables. Seed addition alone may be a limited means of native forb restoration if suitable unoccupied sites are either rare or unpredictable, or if they tend to be close to where the species already occurs.

Spatial niches and coexistence: testing theory with tarweeds.

Competitive coexistence in a spatially heterogeneous environment is traditionally attributed to niche differences, but several recent theories have proposed important additional roles for propagule limitation and chance (e.g., neutral theory, stochastic niche theory, spatial storage effect). We tested whether propagule supply and timing of disturbance affected the coexistence of three ecologically similar plants that replace one another with partial overlap along a local soil gradient. We asked what prevents the species that dominates the most common habitat (Holocarpha virgata, open hillsides) from invading the habitats where the other two species are dominant (Calycadenia pauciflora, rocky hilltops; Hemizonia congesta, clay-rich bottomlands). We added abundant Holocarpha seeds into Calycadenia and Hemizonia habitats that were experimentally disturbed at different times of year. Initial Holocarpha seedling densities in Calycadenia and Hemizonia habitats equaled or exceeded those in unmanipulated Holocarpha habitat, but Holocarpha survival, adult size, and fecundity were much lower outside its own habitat. Holocarpha persisted in Calycadenia and Hemizonia habitats for three years, and springtime disturbance promoted this expansion. However, outside its own habitat Holocarpha showed below-replacement fitness and little competitive effect on the other two species. Our results were most consistent with a deterministic view of spatial niches. Nonetheless, chance events may often cause natural communities to include some transient populations at any given time, leading them to appear "unsaturated" with species.

Fluctuating patch boundaries in a native annual forb: the roles of niche and dispersal limitation.

Abiotic, biotic, and dispersal constraints jointly control the spatial distributions of species, but few studies have directly evaluated how these forces interact and vary over time to create dynamic spatial distributions. Through three years of observation and two years of field manipulation, I investigated simultaneous constraints on the spatial distribution of Lupinus nanus, a native annual legume that grows in dense patches in California grasslands. I transplanted L. nanus across its own patch boundaries, yet within apparently suitable habitat, and assessed the demographic success of naturally occurring and seeded plants in plots with and without competitor removal in years that varied in temperature and rainfall. Core sites were defined as those consistently densely occupied, whereas peripheral sites were densely occupied only during some years, and exterior sites were consistently unoccupied or very sparsely occupied. Site types (core, periphery, and exterior) differed in soil moisture, P, and NO3. Competition limited emergence in all site types in the dry/warm year and in patch peripheries in the wet/cool year. Population fitness (seeds produced per seed added) was > 1.0 in cores during all years. Peripheral sites had fitness near replacement in the wet/cool year, which was greatly increased by competition removal. Exterior fitness was < 1.0 in both experimental years, regardless of seed addition and competitor removal. Seed addition did not increase site-specific fitness, and a seed bank was found to be present in all site types. Herbivory was greater in patch cores and peripheries than in exteriors. Soil variation exerted the most consistent control over patch limits, while competition played an intermittent role in excluding Lupinus from patch peripheries. The dynamic distribution of L. nanus is the product of temporal variation in specific abiotic and biotic niche axes, primarily soil characteristics and competition, rather than dispersal limitation.

Use of community-composition data to predict the fecundity and abundance of species.

Species distribution models are critical tools for the prediction of invasive species spread and conservation of biodiversity. The majority of species distribution models have been built with environmental data. Community ecology theory suggests that species co-occurrence data could also be used to predict current and potential distributions of species. Species assemblages are the products of biotic and environmental constraints on the distribution of individual species and as a result may contain valuable information for niche modeling. We compared the predictive ability of distribution models of annual grassland plants derived from either environmental or community-composition data. Composition-based models were built with the presence or absence of species at a site as predictors of site quality, whereas environment-based models were built with soil chemistry, moisture content, above-ground biomass, and solar radiation as predictors. The reproductive output of experimentally seeded individuals of 4 species and the abundance of 100 species were used to evaluate the resulting models. Community-composition data were the best predictors of both the site-specific reproductive output of sown individuals and the site-specific abundance of existing populations. Successful community-based models were robust to omission of data on the occurrence of rare species, which suggests that even very basic survey data on the occurrence of common species may be adequate for generating such models. Our results highlight the need for increased public availability of ecological survey data to facilitate community-based modeling at scales relevant to conservation.

Invasion in a heterogeneous world: resistance, coexistence or hostile takeover?

We review and synthesize recent developments in the study of the invasion of communities in heterogeneous environments, considering both the invasibility of the community and impacts to the community. We consider both empirical and theoretical studies. For each of three major kinds of environmental heterogeneity (temporal, spatial and invader-driven), we find evidence that heterogeneity is critical to the invasibility of the community, the rate of spread, and the impacts on the community following invasion. We propose an environmental heterogeneity hypothesis of invasions, whereby heterogeneity both increases invasion success and reduces the impact to native species in the community, because it promotes invasion and coexistence mechanisms that are not possible in homogeneous environments. This hypothesis could help to explain recent findings that diversity is often increased as a result of biological invasions. It could also explain the scale dependence of the diversity-invasibility relationship. Despite the undoubted importance of heterogeneity to the invasion of communities, it has been studied remarkably little and new research is needed that simultaneously considers invasion, environmental heterogeneity and community characteristics. As a young field, there is an unrivalled opportunity for theoreticians and experimenters to work together to build a tractable theory informed by data.

Plant competition varies with community composition in an edaphically complex landscape.

There is currently no consensus on how physical and biological factors affect competitive intensity. Tests of whether competitive intensity varies along axes of environmental change have commonly been conducted in systems with a single strong environmental gradient, such as productivity, a soil resource, or an environmental stress. Frequently, these same axes are associated with changes in species composition, yet few studies have asked whether shifts in the identity of competitors affect competitive intensity. We ask whether resources (nutrients, water), stressors (heavy metals, Ca:Mg ratio), productivity (aboveground biomass), or species identity (an ordination axis of plant community composition) were the best predictors of the intensity of competition in a heterogeneous grassland landscape that included multiple independent environmental gradients. The reproductive fitness of six annual plant species was measured in the presence and absence of competitors and used to calculate relative interaction intensity (RII). We found that RII was best predicted by community composition. Nutrient availability was also important, and a post hoc test showed that competitive intensity was best explained by the combined effects of community composition and nutrient availability. We argue that community composition may be the most effective metric for predicting competitive intensity in many ecosystems because it includes both the competitive effects of the local community and information about covarying environmental characteristics.

Propagule vs. niche limitation: untangling the mechanisms behind plant species' distributions.

Distinguishing the roles of propagule limitation and niche requirements in controlling plant species distributions is important for understanding community structure, invasion, and restoration. We used species distribution models based on plant and environmental survey data to assess the strength of species' affinities for particular environmental conditions. We hypothesized that species with statistically detectable environmental requirements were primarily niche-limited, while species with weak habitat affinities were primarily propagule-limited. We tested this hypothesis via a seeding experiment in which we compared species' reproductive fitness in occupied and unoccupied sites. Species that appeared to be niche-limited based on distribution models had lower fitness when planted in unoccupied sites, while species that models suggested were propagule-limited had equivalent fitness when planted in occupied and unoccupied sites. Our results demonstrate that within a single community, both species limited primarily by niche availability or primarily by propagule availability can be identified using observational data.

Adjustments of cognitive control in younger and older adults.

The effects of aging on behavioral and electrophysiological indices of adjustments of cognitive control were examined in two experiments. Specifically, we considered the effects of aging of patterns of response time and modulations of the event-related brain potentials (ERPs) on sequential trial effects, error-related slowing, and local switch costs in two modified Stroop tasks. The behavioral data reveal that sequential trial effects were observed when color, but not word, identification was required and that these effects were similar in younger and older adults; that the degree of error-related slowing was similar for younger and older adults in Experiment 1 and greater in older than younger adults in Experiment 2; that local switch costs in response time were similar in younger and older adults and that the requirement to switch between color and word identification resulted in a dramatic increase in the number of color intrusion errors in older adults in Experiment 2. The ERP data revealed that endogenously generated adjustments of cognitive control were associated with a parietal slow wave that mirrored the behavioral data and was similar in amplitude in younger and older adults and an anterior frontal slow wave that was absent in older adults. The ERP data also revealed that an enhancement of the P3 component and a frontal slow wave that differentiated color switch trials from color non-switch and word trials in younger adults were attenuated in older adults.

Emergence of resistant microbes in critical care units is transient, despite an unrestricted formulary and multiple antibiotic trials.

BACKGROUND: Antimicrobial resistance is a growing problem in the intensive care setting. This study was designed to evaluate the trends in bacterial prevalence and changes in antibiotic resistance at a large university hospital over the past decade. Antimicrobial resistance data were compared among the surgical intensive care unit (SICU), medical intensive care unit (MICU), and burn unit (BNU). MATERIALS AND METHODS: A large database was created using hospital-wide data from 1989 to 2000. A retrospective analysis of the evolution of organism prevalence, antibiotic resistance, and response to study protocols was evaluated. The formulary was relatively unrestricted. All positive cultures were examined, focusing on wound, blood, and sputum cultures. Six primary antibiotics were targeted specifically to follow resistance patterns. RESULTS: There were 847 identified positive wound cultures, 2,862 positive sputum cultures, and 2,252 positive blood cultures. The incidence of gram-positive and gram-negative organisms changed little in the SICU and BNU; however, there was a large increase in gram-positive organisms and yeast in the MICU over the past 5 years. Anaerobic bacteria and yeast were nearly nonexistent pathogens in the SICU and BNU. The resistance pattern of most organisms changed little following the introduction of a new antibiotic. However, the effectiveness of study antibiotics after formal clinical study periods decreased dramatically, albeit transiently. CONCLUSION: Hospital-wide antibiotic resistance data may be misleading and may not reflect individual critical care units throughout the hospital. Bacterial flora, including resistant organisms, changed little over 10 years, despite an unrestricted formulary. The emergence of resistant and opportunistic organisms is related to antibiotic usage and can vary significantly over time. This suggests that a policy of administering limited duration, narrow spectrum antibiotics may reduce drug resistance.

Propagule limitation, disparate habitat quality, and variation in phenotypic selection at a local species range boundary.

Adaptation to novel conditions beyond current range boundaries requires the presence of suitable sites within dispersal range, but may be impeded when emigrants encounter poor habitat and sharply different selection pressures. We investigated fine-scale spatial heterogeneity in ecological dynamics and selection at a local population boundary of the annual plant Gilia tricolor. In two years, we planted G. tricolor seeds in core habitat, margin habitat at the edge of the local range, and exterior habitat in order to measure spatial and temporal variation in habitat quality, opportunity for selection, and selection on phenotypic traits. We found a striking decline in average habitat quality with distance from the population core, yet some migrant seeds were successful in suitable, unoccupied microsites at and beyond the range boundary. Total and direct selection on four out of five measured phenotypic traits varied across habitat zones, as well as between years. Moreover, the margin habitat often exerted unique selection pressures that were not intermediate between core and exterior habitats. This study reveals that a combination of ecological and evolutionary forces, including propagule limitation, variation in habitat quality and spatial heterogeneity in phenotypic selection may reduce opportunities for adaptive range expansion, even across a very local population boundary.