Role of a grass riparian zone in controlling the fate of nitrogen in a poorly drained agricultural landscape

Riparian ecosystems, through their unique positions in the agricultural landscape, have the potential to mitigate nutrient loading to streams. This study was conducted to gain a better understanding of N cycling in a poorly drained Grass Riparian Zone (GRZ) and adjacent Perennial Ryegrass seed Field (PRF) in the Willamette Valley, Oregon, U.SA. Tracer studies showed higher recovery of ¹⁵N in the PRF than the GRZ due to higher plant uptake and soil retention by the PRF. Prolonged flooding in the GRZ most likely resulted in higher denitrification and lower plant uptake and soil retention of ¹⁵N. More PRF plant biomass N was available for mineralization and NO₃⁻ accumulation during the summer. Shallow (30-45 cm) and deeper (135-150 cm) soil water NO₃⁻ concentrations were higher in the PRF than the GRZ. Dilution, from precipitation, and biological consumption were most likely responsible for decreases in soil water NO₃⁻ seen in the PRF and as water moved into the GRZ. When soil water NO₃⁻ that was not processed in the PRF entered the GRZ, it was consumed within 6 m in shallow soil water and 17 m for deeper soil water. High carbon and low oxygen in the shallow soils of the GRZ most likely contributed to highest denitrification potential (DNP) rates just inside the GRZ. Dissimilatory nitrate reduction to NH₄⁺ (DNRA) rates in the GRZ surface soil indicated this process together with plant uptake and denitrification, could easily account for the consumption of NO₃⁻ in incoming shallow soil water. Differences in the management of the GRZ and PRF translated into differences in subsoil carbon and NO₃⁻ but did not influence DNP or DNRA rates in the subsoil. Based on measured DNP rates, it was unlikely that denitrification alone could have accounted for decreases in deep soil water NO₃⁻. The discrepancy between DNP rates and loss of soil water NO₃⁻ may have been due to DNRA or unmeasured hotspots of denitrification activity. This study showed that the low maintenance, poorly drained grass riparian zone supported conditions that promoted the consumption of soil water NO₃⁻

Why Clowns Taste Funny: The Relationship between Humor and Semantic Ambiguity

What makes us laugh? One crucial component of many jokes is the disambiguation of words with multiple meanings. In this functional MRI study of normal participants, the neural mechanisms that underlie our experience of getting a joke that depends on the resolution of semantically ambiguous words were explored. Jokes that contained ambiguous words were compared with sentences that contained ambiguous words but were not funny, as well as to matched verbal jokes that did not depend on semantic ambiguity. The results confirm that both the left inferior temporal gyrus and left inferior frontal gyrus are involved in processing the semantic aspects of language comprehension, while a more widespread network that includes both of these regions and the temporoparietal junction bilaterally is involved in processing humorous verbal jokes when compared with matched nonhumorous material. In addition, hearing jokes was associated with increased activity in a network of subcortical regions, including the amygdala, the ventral striatum, and the midbrain, that have been implicated in experiencing positive reward. Moreover, activity in these regions correlated with the subjective ratings of funniness of the presented material. These results allow a more precise account of how the neural and cognitive processes that are involved in ambiguity resolution contribute to the appreciation of jokes that depend on semantic ambiguity

Solving mixed sparse-dense linear least-squares problems by preconditioned iterative methods

The efficient solution of large linear least-squares problems in which the system matrix A contains rows with very different densities is challenging. Previous work has focused on direct methods for problems in which A has a few relatively dense rows. These rows are initially ignored, a factorization of the sparse part is computed using a sparse direct solver, and then the solution is updated to take account of the omitted dense rows. In some practical applications the number of dense rows can be significant and for very large problems, using a direct solver may not be feasible. We propose processing rows that are identified as dense separately within a conjugate gradient method using an incomplete factorization preconditioner combined with the factorization of a dense matrix of size equal to the number of dense rows. Numerical experiments on large-scale problems from real applications are used to illustrate the effectiveness of our approach. The results demonstrate that we can efficiently solve problems that could not be solved by a preconditioned conjugate gradient method without exploiting the dense rows

Multichannel Diffuse Optical Raman Tomography for Bone Characterization In Vivo: a Phantom Study

Raman spectroscopy is used to gather information on the mineral and organic components of bone tissue to analyze their composition. By measuring the Raman signal of bone through spatially offset Raman spectroscopy the health of the bone can be determined. We’ve customized a system with 8 collection channels that consist of individual fibers, which are coupled to separate spectrometers and cooled CCDs. This parallel detection system was used to scan gelatin phantoms with Teflon inclusions of two sizes. Raman signals were decoupled from the autofluorescence background using channel specific polynomial fitting. Images with high contrast to background ratios of Raman yield and accurate spatial resolution were recovered using a model-based diffuse tomography approach

Listeners and readers generalise their experience with word meanings across modalities

Research has shown that adults’ lexical-semantic representations are surprisingly malleable. For instance, the interpretation of ambiguous words (e.g. bark) is influenced by experience such that recently encountered meanings become more readily available (Rodd et al., 2016, 2013). However the mechanism underlying this word-meaning priming effect remains unclear, and competing accounts make different predictions about the extent to which information about word meanings that is gained within one modality (e.g. speech) is transferred to the other modality (e.g. reading) to aid comprehension. In two web-based experiments, ambiguous target words were primed with either written or spoken sentences that biased their interpretation toward a subordinate meaning, or were unprimed. About 20 minutes after the prime exposure, interpretation of these target words was tested by presenting them in either written or spoken form, using word association (Experiment 1, N=78) and speeded semantic relatedness decisions (Experiment 2, N=181). Both experiments replicated the auditory unimodal priming effect shown previously (Rodd et al., 2016, 2013) and revealed significant cross-modal priming: primed meanings were retrieved more frequently and swiftly across all primed conditions compared to the unprimed baseline. Furthermore, there were no reliable differences in priming levels between unimodal and cross-modal prime-test conditions. These results indicate that recent experience with ambiguous word meanings can bias the reader’s or listener’s later interpretation of these words in a modality-general way. We identify possible loci of this effect within the context of models of long-term priming and ambiguity resolution

Mitigation of Shallow Groundwater Nitrate in a Poorly Drained Riparian Area and Adjacent Cropland

Riparian ecosystems, through their unique position in the agricultural landscape and ability to influence nutrient cycles, can potentially reduce NO3 loading to surface and ground waters. The purpose of this study was to determine the fate of NO3 in shallow groundwater moving along a lateral flowpath from a grass seed cropping system through an undisturbed mixed-species herbaceous riparian area. Soil A (30–45 cm) and C horizon (135–150 cm) NO3, dissolved oxygen, and nitrous oxide concentrations were significantly higher in the cropping system than the adjacent riparian area. Nitrate concentrations in both horizons of the riparian soil were consistently at or below 0.05 mg NL-1 while cropping system concentrations ranged from 1 to 12 mg N L-1. Chloride data suggested that NO3 dilution occurred from recharge by precipitation. However, a sharp decrease in NO3/Cl ratios as water moved into the riparian area indicated that additional dilution of NO3 concentrations was unlikely. Riparian area A horizon soil water had higher dissolved organic carbon than the cropping system and when the riparian soil became saturated, available electron acceptors (O2, NO3) were rapidly reduced. Dissolved inorganic carbon was significantly higher in the riparian area than the cropping system for both horizons indicating high biological activity. Carbon limitation in the cropping system may have led to microbial respiration using primarily O2 and to a lesser degree NO3. Within 6 m of the riparian/cropping system transition, NO3 was virtually undetectable

The Neural Time Course of Semantic Ambiguity Resolution in Speech Comprehension.

Semantically ambiguous words challenge speech comprehension, particularly when listeners must select a less frequent (subordinate) meaning at disambiguation. Using combined magnetoencephalography (MEG) and EEG, we measured neural responses associated with distinct cognitive operations during semantic ambiguity resolution in spoken sentences: (i) initial activation and selection of meanings in response to an ambiguous word and (ii) sentence reinterpretation in response to subsequent disambiguation to a subordinate meaning. Ambiguous words elicited an increased neural response approximately 400-800 msec after their acoustic offset compared with unambiguous control words in left frontotemporal MEG sensors, corresponding to sources in bilateral frontotemporal brain regions. This response may reflect increased demands on processes by which multiple alternative meanings are activated and maintained until later selection. Disambiguating words heard after an ambiguous word were associated with marginally increased neural activity over bilateral temporal MEG sensors and a central cluster of EEG electrodes, which localized to similar bilateral frontal and left temporal regions. This later neural response may reflect effortful semantic integration or elicitation of prediction errors that guide reinterpretation of previously selected word meanings. Across participants, the amplitude of the ambiguity response showed a marginal positive correlation with comprehension scores, suggesting that sentence comprehension benefits from additional processing around the time of an ambiguous word. Better comprehenders may have increased availability of subordinate meanings, perhaps due to higher quality lexical representations and reflected in a positive correlation between vocabulary size and comprehension success

Montreal Cognitive Assessment for the diagnosis of Alzheimer's disease and other dementias.

BACKGROUND: Dementia is a progressive syndrome of global cognitive impairment with significant health and social care costs. Global prevalence is projected to increase, particularly in resource-limited settings. Recent policy changes in Western countries to increase detection mandates a careful examination of the diagnostic accuracy of neuropsychological tests for dementia. OBJECTIVES: To determine the diagnostic accuracy of the Montreal Cognitive Assessment (MoCA) at various thresholds for dementia and its subtypes. SEARCH METHODS: We searched MEDLINE, EMBASE, BIOSIS Previews, Science Citation Index, PsycINFO and LILACS databases to August 2012. In addition, we searched specialised sources containing diagnostic studies and reviews, including MEDION (Meta-analyses van Diagnostisch Onderzoek), DARE (Database of Abstracts of Reviews of Effects), HTA (Health Technology Assessment Database), ARIF (Aggressive Research Intelligence Facility) and C-EBLM (International Federation of Clinical Chemistry and Laboratory Medicine Committee for Evidence-based Laboratory Medicine) databases. We also searched ALOIS (Cochrane Dementia and Cognitive Improvement Group specialized register of diagnostic and intervention studies). We identified further relevant studies from the PubMed 'related articles' feature and by tracking key studies in Science Citation Index and Scopus. We also searched for relevant grey literature from the Web of Science Core Collection, including Science Citation Index and Conference Proceedings Citation Index (Thomson Reuters Web of Science), PhD theses and contacted researchers with potential relevant data. SELECTION CRITERIA: Cross-sectional designs where all participants were recruited from the same sample were sought; case-control studies were excluded due to high chance of bias. We searched for studies from memory clinics, hospital clinics, primary care and community populations. We excluded studies of early onset dementia, dementia from a secondary cause, or studies where participants were selected on the basis of a specific disease type such as Parkinson's disease or specific settings such as nursing homes. DATA COLLECTION AND ANALYSIS: We extracted dementia study prevalence and dichotomised test positive/test negative results with thresholds used to diagnose dementia. This allowed calculation of sensitivity and specificity if not already reported in the study. Study authors were contacted where there was insufficient information to complete the 2x2 tables. We performed quality assessment according to the QUADAS-2 criteria.Methodological variation in selected studies precluded quantitative meta-analysis, therefore results from individual studies were presented with a narrative synthesis. MAIN RESULTS: Seven studies were selected: three in memory clinics, two in hospital clinics, none in primary care and two in population-derived samples. There were 9422 participants in total, but most of studies recruited only small samples, with only one having more than 350 participants. The prevalence of dementia was 22% to 54% in the clinic-based studies, and 5% to 10% in population samples. In the four studies that used the recommended threshold score of 26 or over indicating normal cognition, the MoCA had high sensitivity of 0.94 or more but low specificity of 0.60 or less. AUTHORS' CONCLUSIONS: The overall quality and quantity of information is insufficient to make recommendations on the clinical utility of MoCA for detecting dementia in different settings. Further studies that do not recruit participants based on diagnoses already present (case-control design) but apply diagnostic tests and reference standards prospectively are required. Methodological clarity could be improved in subsequent DTA studies of MoCA by reporting findings using recommended guidelines (e.g. STARDdem). Thresholds lower than 26 are likely to be more useful for optimal diagnostic accuracy of MoCA in dementia, but this requires confirmation in further studies.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/14651858.CD010775.pub

An Open Trial of Group Acceptance and Commitment Therapy (ACT) With an Adjunctive Mobile App for Generalized Anxiety Disorder (GAD)

Generalized anxiety disorder (GAD) is a common and debilitating condition. Effective treatments exist, but they are time-and resource-intensive. This study tested the initial efficacy and acceptability of a novel treatment protocol designed to increase efficiency: acceptance and commitment therapy (ACT) taught in groups and through an adjunctive mobile app. Participants were 21 individuals with GAD who received six weeks of 2-hour group ACT sessions as well as access to an adjunctive ACT mobile app. Significant improvements occurred in worry, anxiety, social functioning, and depression as well as relevant processes (psychological inflexibility, anxiety-related cognitive fusion). In-the-moment improvements were also observed in symptoms and ACT processes immediately after completing mobile app sessions. Treatment was perceived as credible and acceptable overall. However, rates of reliable and clinically significant change were low, and app usage did not correlate with change in worry. Overall, this study suggests that an efficient, brief ACT group intervention combined with a mobile app may lead to improvements in GAD but may not be sufficient for clinically significant change. A detailed overview of the treatment is included, and guidance for clinicians interested in implementing this protocol is discussed

Accent modulates access to word meaning: Evidence for a speaker-model account of spoken word recognition

Speech carries accent information relevant to determining the speaker’s linguistic and social background. A series of web-based experiments demonstrate that accent cues can modulate access to word meaning. In Experiments 1-3, British participants were more likely to retrieve the American dominant meaning (e.g., hat meaning of “bonnet”) in a word association task if they heard the words in an American than a British accent. In addition, results from a speeded semantic decision task (Experiment 4) and sentence comprehension task (Experiment 5) confirm that accent modulates on-line meaning retrieval such that comprehension of ambiguous words is easier when the relevant word meaning is dominant in the speaker’s dialect. Critically, neutral-accent speech items, created by morphing British- and American-accented recordings, were interpreted in a similar way to accented words when embedded in a context of accented words (Experiment 2). This finding indicates that listeners do not use accent to guide meaning retrieval on a word-by-word basis; instead they use accent information to determine the dialectic identity of a speaker and then use their experience of that dialect to guide meaning access for all words spoken by that person. These results motivate a speaker-model account of spoken word recognition in which comprehenders determine key characteristics of their interlocutor and use this knowledge to guide word meaning access