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result(s) for
"Allen, T.W"
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Susceptibility to Ebbinghaus and Müller-Lyer illusions in autistic children: a comparison of three different methods
by
Morgan, Michael J.
,
Allen, Craig T. W.
,
Pellicano, Elizabeth
in
Adjustment
,
Adolescent
,
Autism
2017
Background
Studies reporting altered susceptibility to visual illusions in autistic individuals compared to that typically developing individuals have been taken to reflect differences in perception (e.g. reduced global processing), but could instead reflect differences in higher-level decision-making strategies.
Methods
We measured susceptibility to two contextual illusions (Ebbinghaus, Müller-Lyer) in autistic children aged 6–14 years and typically developing children matched in age and non-verbal ability using three methods. In experiment 1, we used a new two-alternative-forced-choice method with a roving pedestal designed to minimise cognitive biases. Here, children judged which of two comparison stimuli was most similar in size to a reference stimulus. In experiments 2 and 3, we used methods previously used with autistic populations. In experiment 2, children judged whether stimuli were the ‘same’ or ‘different’, and in experiment 3, we used a method-of-adjustment task.
Results
Across all tasks, autistic children were equally susceptible to the Ebbinghaus illusion as typically developing children. Autistic children showed a
heightened
susceptibility to the Müller-Lyer illusion, but only in the method-of-adjustment task. This result may reflect differences in decisional criteria.
Conclusions
Our results are inconsistent with theories proposing reduced contextual integration in autism and suggest that previous reports of altered susceptibility to illusions may arise from differences in decision-making, rather than differences in perception per se. Our findings help to elucidate the underlying reasons for atypical responses to perceptual illusions in autism and call for the use of methods that reduce cognitive bias when measuring illusion susceptibility.
Journal Article
Variable adhesion and diurnal population patterns of epiphytic yeasts on creeping bentgrass
by
Buck, J.W
,
Allen, T.W
,
Burpee, L.L
in
Agrostis
,
Agrostis - microbiology
,
Agrostis stolonifera var. palustris
2006
Irrigation and an in vitro agitation assay were used to determine the percentage of the epiphytic yeast community (Cryptococcus, Pseudozyma, Rhodotorula, and Sporobolomyces) adhering to the phylloplane of creeping bentgrass (Agrostis palustris (Huds.) Pers.). Colony-forming units (cfu) of total epiphytic yeast populations (adherent and nonadherent cells) and of adherent populations (cells not removed by agitation) were determined by leaf washing and dilution plating. In an in vitro assay, 40.0% and 57.1% of the yeast adhered to the leaves, whereas, in initial field trials the percentage of adherent yeasts ranged from 40.0% to 71.9% of the total population. Adherent yeast cfu on leaves in the morning were significantly lower on bentgrass (8.0 × 10
3
to 3.1 × 10
4
cfu·cm
-2
) compared with total yeast cfu (1.4 × 10
4
to 4.7 × 10
4
cfu·cm
-2
) on the nonirrigated control. No differences in yeast populations were observed between irrigated and nonirrigated plots 2 h after the 0900 treatments. Yeast populations followed a diurnal pattern, with larger cfu recovered from bentgrass leaves in the morning and significantly lower populations recovered in the afternoon. At 1400 the adherent yeast were 83.1%-100% of the total yeast population recovered from the leaves. The relative adhesiveness of the epiphytic yeast community on bentgrass leaves is dynamic with nonadherent cells making up a larger percentage of the population in the mornings than the afternoons.Key words: adherence, Cryptococcus, leaf surface, Rhodotorula, turfgrass.
Journal Article
In vitro attachment of phylloplane yeasts to Botrytis cinerea, Rhizoctonia solani, and Sclerotinia homoeocarpa
2004
The ability of yeasts to attach to hyphae or conidia of phytopathogenic fungi has been speculated to contribute to biocontrol activity on plant surfaces. Attachment of phylloplane yeasts to Botrytis cinerea, Rhizoctonia solani, and Sclerotinia homoeocarpa was determined using in vitro attachment assays. Yeasts were incubated for 2 d on potato dextrose agar (PDA) prior to experimentation. A total of 292 yeasts cultured on PDA were screened for their ability to attach to conidia of B. cinerea; 260 isolates (89.1%) attached to conidia forming large aggregates of cells, and 22 isolates (7.5%) weakly attached to conidia with 1 or 2 yeast cells attached to a few conidia. Ten yeasts (3.4%), including 8 isolates of Cryptococcus laurentii, 1 isolate of Cryptococcus flavescens, and an unidentified species of Cryptococcus, failed to attach to conidia. All non-attaching yeasts produced copious extracellular polysaccharide (EPS) on PDA. Seventeen yeast isolates did not attach to hyphal fragments of B. cinerea, R. solani, and S. homoeocarpa after a 1 h incubation, but attachment was observed after 24 h. Culture medium, but not culture age, significantly affected the attachment of yeast cells to conidia of B. cinerea. The 10 yeast isolates that did not attach to conidia when grown on agar did attach to conidia (20%-57% of conidia with attached yeast cells) when cultured in liquid medium. Attachment of the biocontrol yeast Rhodotorula glutinis PM4 to conidia of B. cinerea was significantly greater at 1 × 10
7
yeast cells·mL
-1
than at lower concentrations of yeast cells. The ability of yeast cells to attach to fungal conidia or hyphae appears to be a common phenotype among phylloplane yeasts.Key words: adhesion, biological control, Cryptococcus laurentii, Rhodotorula glutinis.
Journal Article
Effect of environmental characteristics on Pythium and Mesocriconema spp. in golf course greens in Alabama
2005
The role the environment has on populations of Pythium and Mesocriconema spp. was investigated at 5 golf course locations in east central Alabama. Every 4 to 5 weeks soil samples were collected from 3 golf greens on each of the 5 golf courses. Environmental data, including air and soil temperature, pH and relative humidity, were also collected. Dilution plating and a combined sieving and sugar flotation procedure were conducted to determine the populations of Pythium and Mesocriconema spp. for each month. Isolates of Pythium from 4 months were also identified. Pythium spp. populations increased as soil temperature and ambient air temperature prior to sampling decreased (P < 0.05). Pythium spp. populations were highest in the winter and lowest in the spring. At some locations, populations of Mesocriconema spp. increased as soil acidity and populations of Pythium spp. decreased (P < 0.05) and as ambient air temperature prior to sampling increased (P < 0.05). Eight species of Pythium were isolated from 4 months, with Pythium rostratum being the most commonly isolated. Results suggest that Pythium and Mesocriconema spp. prefer different soil environments.Key words: Cynodon dactylon × traansvalensis, Poa trivialis, ring nematodes, turfgrass.
Journal Article
Molecular evidence of N-methyl-D-aspartate receptor hypofunction in schizophrenia
2013
Blockade of
N
-methyl-
D
-aspartate receptors (NMDARs) produces behavior in healthy people that is similar to the psychotic symptoms and cognitive deficits of schizophrenia and can exacerbate symptoms in people with schizophrenia. However, an endogenous brain disruption of NMDARs has not been clearly established in schizophrenia. We measured mRNA transcripts for five NMDAR subunit mRNAs and protein for the NR1 subunit in the dorsolateral prefrontal cortex (DLPFC) of schizophrenia and control (
n
=74) brains. Five NMDAR single-nucleotide polymorphisms (SNPs) previously associated with schizophrenia were tested for association with NMDAR mRNAs in postmortem brain and for association with cognitive ability in an antemortem cohort of 101 healthy controls and 48 people with schizophrenia. The NR1 subunit (mRNA and protein) and NR2C mRNA were decreased in postmortem brain from people with schizophrenia (
P
=0.004,
P
=0.01 and
P
=0.01, respectively). In the antemortem cohort, the minor allele of NR2B rs1805502 (T5988C) was associated with significantly lower reasoning ability in schizophrenia. In the postmortem brain, the NR2B rs1805502 (T5988C) C allele was associated with reduced expression of NR1 mRNA and protein in schizophrenia. Reduction in NR1 and NR2C in the DLPFC of people with schizophrenia may lead to altered NMDAR stoichiometry and provides compelling evidence for an endogenous NMDAR deficit in schizophrenia. Genetic variation in the
NR2B
gene predicts reduced levels of the obligatory NR1 subunit, suggesting a novel mechanism by which the NR2B SNP may negatively influence other NMDAR subunit expression and reasoning ability in schizophrenia.
Journal Article
Seasonal origins of soil water used by trees
by
Kirchner, James W.
,
Siegwolf, Rolf T. W.
,
Allen, Scott T.
in
Analysis
,
Annual precipitation
,
Aquifers
2019
Rain recharges soil water storages and either percolates downward into aquifers and streams or is returned to the atmosphere through evapotranspiration. Although it is commonly assumed that summer rainfall recharges plant-available water during the growing season, the seasonal origins of water used by plants have not been systematically explored. We characterize the seasonal origins of waters in soils and trees by comparing their midsummer isotopic signatures (δ2H) to seasonal isotopic cycles in precipitation, using a new seasonal origin index. Across 182 Swiss forest sites, xylem water isotopic signatures show that summer rain was not the predominant water source for midsummer transpiration in any of the three sampled tree species. Beech and oak mostly used winter precipitation, whereas spruce used water of more diverse seasonal origins. Even in the same plots, beech consistently used more winter precipitation than spruce, demonstrating consistent niche partitioning in the rhizosphere. All three species' xylem water isotopes indicate that trees used more winter precipitation in drier regions, potentially mitigating their vulnerability to summer droughts. The widespread occurrence of winter isotopic signatures in midsummer xylem implies that growing-season rainfall may have minimally recharged the soil water storages that supply tree growth, even across diverse humid climates (690–2068 mm annual precipitation). These results challenge common assumptions concerning how water flows through soils and is accessed by trees. Beyond these ecological and hydrological implications, our findings also imply that stable isotopes of δ18O and δ2H in plant tissues, which are often used in climate reconstructions, may not reflect water from growing-season climates.
Journal Article
Association of serum VEGF levels with prefrontal cortex volume in schizophrenia
2016
A large body of evidence indicates alterations in brain regional cellular energy metabolism and blood flow in schizophrenia. Among the different molecules regulating blood flow, vascular endothelial growth factor (VEGF) is generally accepted as the major factor involved in the process of angiogenesis. In the present study, we examined whether peripheral VEGF levels correlate with changes in the prefrontal cortex (PFC) volume in patients with schizophrenia and in healthy controls. Whole-blood samples were obtained from 96 people with schizophrenia or schizoaffective disorder and 83 healthy controls. Serum VEGF protein levels were analyzed by enzyme-linked immunosorbent assay, whereas quantitative PCR was performed to measure interleukin-6 (IL-6, a pro-inflammatory marker implicated in schizophrenia) mRNA levels in the blood samples. Structural magnetic resonance imaging scans were obtained using a 3T Achieva scanner on a subset of 59 people with schizophrenia or schizoaffective disorder and 65 healthy controls, and prefrontal volumes were obtained using FreeSurfer software. As compared with healthy controls, individuals with schizophrenia had a significant increase in log-transformed mean serum VEGF levels (
t
(177)=2.9,
P
=0.005). A significant inverse correlation (
r
=−0.40,
P
=0.002) between serum VEGF and total frontal pole volume was found in patients with schizophrenia/schizoaffective disorder. Moreover, we observed a significant positive association (
r
=0.24,
P
=0.03) between serum VEGF and IL-6 mRNA levels in patients with schizophrenia. These findings suggest an association between serum VEGF and inflammation, and that serum VEGF levels are related to structural abnormalities in the PFC of people with schizophrenia.
Journal Article
Primary CNS Alveolar Rhabdomyosarcoma: Importance of Epigenetic and Transcriptomic Assays for Accurate Diagnosis
by
Jour, George
,
Koelsche, Christian
,
Allen, Jeffrey
in
Brain cancer
,
Case studies
,
Central nervous system diseases
2019
Abstract
We present the case of a 22-year-old woman who developed increasing headaches, nausea, and vomiting. Imaging identified a 3 × 3 cm heterogeneously enhancing cystic mass in the posterior III ventricular/pineal region. Pathology review of the initial lesion revealed a highly malignant spindle cell neoplasm composed of round to mostly oval elongated cells with relatively small amounts of cytoplasm arranged in sheets and fascicles with focal storiform pattern. Whole genome methylation analysis through unsupervised clustering with data generated from other primary intracranial tumors and peripheral sarcomas was performed at the German Cancer Research Center (DKFZ) and classified the tumor with the group of alveolar rhabdomyosarcomas (ARMS). Further RNA sequencing revealed an in frame PAX3 (EX 7)-NCOA2 (EX12) fusion confirming the diagnosis. This is the first evidence of occurrence of PAX3-NCOA2 in primary CNS ARMS.
Journal Article
Metamodels for Computer-based Engineering Design: Survey and recommendations
by
Simpson, T.W.
,
Poplinski, J.D.
,
Koch, P. N.
in
Approximation
,
Design of experiments
,
Engineering design
2001
The use of statistical techniques to build approximations of expensive computer analysis codes pervades much of today's engineering design. These statistical approximations, or metamodels, are used to replace the actual expensive computer analyses, facilitating multidisciplinary, multiobjective optimization and concept exploration. In this paper, we review several of these techniques, including design of experiments, response surface methodology, Taguchi methods, neural networks, inductive learning and kriging. We survey their existing application in engineering design, and then address the dangers of applying traditional statistical techniques to approximate deterministic computer analysis codes. We conclude with recommendations for the appropriate use of statistical approximation techniques in given situations, and how common pitfalls can be avoided. [PUBLICATION ABSTRACT]
Journal Article
Applied historical ecology: using the past to manage for the future
by
Allen, Craig D.
,
Betancourt, Julio L.
,
Swetnam, Thomas W.
in
Archives
,
Climate change
,
Coniferous forests
1999
Applied historical ecology is the use of historical knowledge in the management of ecosystems. Historical perspectives increase our understanding of the dynamic nature of landscapes and provide a frame of reference for assessing modern patterns and processes. Historical records, however, are often too brief or fragmentary to be useful, or they are not obtainable for the process or structure of interest. Even where long historical time series can be assembled, selection of appropriate reference conditions may be complicated by the past influence of humans and the many potential reference conditions encompassed by nonequilibrium dynamics. These complications, however, do not lessen the value of history; rather they underscore the need for multiple, comparative histories from many locations for evaluating both cultural and natural causes of variability, as well as for characterizing the overall dynamical properties of ecosystems. Historical knowledge may not simplify the task of setting management goals and making decisions, but 20th century trends, such as increasingly severe wildfires, suggest that disregarding history can be perilous. We describe examples from our research in the southwestern United States to illustrate some of the values and limitations of applied historical ecology. Paleoecological data from packrat middens and other natural archives have been useful for defining baseline conditions of vegetation communities, determining histories and rates of species range expansions and contractions, and discriminating between natural and cultural causes of environmental change. We describe a montane grassland restoration project in northern New Mexico that was justified and guided by an historical sequence of aerial photographs showing progressive tree invasion during the 20th century. Likewise, fire scar chronologies have been widely used to justify and guide fuel reduction and natural fire reintroduction in forests. A southwestern network of fire histories illustrates the power of aggregating historical time series across spatial scales. Regional fire patterns evident in these aggregations point to the key role of interannual lags in responses of fuels and fire regimes to the El Nino-Southern Oscillation (wet/dry cycles), with important implications for long-range fire hazard forecasting. These examples of applied historical ecology emphasize that detection and explanation of historical trends and variability are essential to informed management.
Journal Article