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Three case-studies, using longitudinal records of children's spontaneous speech, illustrate what happens when a child's syntax changes. The first, examining acquisition of English verb-particle constructions, shows a near-total absence of commission errors. The second, examining acquisition of prepositional questions in English or Spanish, shows that children (i) may go as long as 9 months producing both direct-object questions and declaratives with prepositional phrases, before first attempting a prepositional question; and (ii) at some point, abrubtly begin producing prepositional questions that are correctly formed for the target language. The third case study shows that in children acquiring English, the onset of verb-particle constructions occurs almost exactly when that child begins using novel noun-noun compounds. After a discussion of the implications for the nature of syntactic knowledge, and for the mechanisms by which it is acquired, two examples are presented of as-yet untested acquisitional predictions of parametric proposals in the syntax literature.
Scientific quality and feasibility are part of ethics review by Institutional Review Boards (IRBs). Scientific Review Committees (SRCs) were proposed to facilitate this assessment by the Clinical and Translational Science Award (CTSA) SRC Consensus Group. This study assessed SRC feasibility and impact at CTSA-affiliated academic health centers (AHCs).
SRC implementation at 10 AHCs was assessed pre/post-intervention using quantitative and qualitative methods. Pre-intervention, four AHCs had no SRC, and six had at least one SRC needing modifications to better align with Consensus Group recommendations.
Facilitators of successful SRC implementation included broad-based communication, an external motivator, senior-level support, and committed SRC reviewers. Barriers included limited resources and staffing, variable local mandates, limited SRC authority, lack of anticipated benefit, and operational challenges. Research protocol quality did not differ significantly between study periods, but respondents suggested positive effects. During intervention, median total review duration did not lengthen for the 40% of protocols approved within 3 weeks. For the 60% under review after 3 weeks, review was lengthened primarily due to longer IRB review for SRC-reviewed protocols. Site interviews recommended designing locally effective SRC processes, building buy-in by communication or by mandate, allowing time for planning and sharing best practices, and connecting SRC and IRB procedures.
The CTSA SRC Consensus Group recommendations appear feasible. Although not conclusive in this relatively short initial implementation, sites perceived positive impact by SRCs on study quality. Optimal benefit will require local or federal mandate for implementation, adapting processes to local contexts, and employing SRC stipulations.
Brain regions are functionally diverse, and a given region may engage in a variety of tasks. This functional diversity of brain regions may be one factor that has prevented the finding of consistent biomarkers for brain disorders such as autism spectrum disorder (ASD). Thus, methods to characterise brain regions would help to determine how functional abnormalities contribute to affected behaviours.
As the first illustration of the meta-analytic behavioural profiling procedure, we evaluated how the regions with disrupted connectivity in ASD contributed to various behaviours.
Connectivity abnormalities were determined from a published degree centrality group comparison based on functional magnetic resonance imaging data from the Autism Brain Imaging Data Exchange. Using BrainMap's database of task-based neuroimaging studies, behavioural profiles were created for abnormally connected regions by relating these regions to tasks activating them.
Hyperconnectivity in ASD brains was significantly related to memory, attention, reasoning, social, execution and speech behaviours. Hypoconnectivity was related to vision, execution and speech behaviours.
The procedure outlines the first clinical neuroimaging application of a behavioural profiling method that estimates the functional diversity of brain regions, allowing for the relation of abnormal functional connectivity to diagnostic criteria. Behavioural profiling and the computational insights it provides can facilitate better understanding of the functional manifestations of various disorders, including ASD.
Identifying routes of transmission among hospitalized patients during a healthcare-associated outbreak can be tedious, particularly among patients with complex hospital stays and multiple exposures. Data mining of the electronic health record (EHR) has the potential to rapidly identify common exposures among patients suspected of being part of an outbreak.
We retrospectively analyzed 9 hospital outbreaks that occurred during 2011–2016 and that had previously been characterized both according to transmission route and by molecular characterization of the bacterial isolates. We determined (1) the ability of data mining of the EHR to identify the correct route of transmission, (2) how early the correct route was identified during the timeline of the outbreak, and (3) how many cases in the outbreaks could have been prevented had the system been running in real time.
Correct routes were identified for all outbreaks at the second patient, except for one outbreak involving >1 transmission route that was detected at the eighth patient. Up to 40 or 34 infections (78% or 66% of possible preventable infections, respectively) could have been prevented if data mining had been implemented in real time, assuming the initiation of an effective intervention within 7 or 14 days of identification of the transmission route, respectively.
Data mining of the EHR was accurate for identifying routes of transmission among patients who were part of the outbreak. Prospective validation of this approach using routine whole-genome sequencing and data mining of the EHR for both outbreak detection and route attribution is ongoing.
We investigated whether older adults are more likely than younger adults to violate a foundational property of rational decision making, the axiom of transitive preference. Our experiment consisted of two groups, older (ages 60-75; 21 participants) and younger (ages 18-30; 20 participants) adults. We used Bayesian model selection to investigate whether individuals were better described via (transitive) weak order-based decision strategies or (possibly intransitive) lexicographic semiorder decision strategies. We found weak evidence for the hypothesis that older adults violate transitivity at a higher rate than younger adults. At the same time, a hierarchical Bayesian analysis suggests that, in this study, the distribution of decision strategies across individuals is similar for both older and younger adults.
The objective of this study was to evaluate weed control, crop yields, potential soil loss, and net returns to management of an integrated weed management system in no-till corn and soybean compared to an herbicide-based strategy. The integrated weed management system reduced herbicide inputs by delayed cover crop termination, herbicide banding, and high-residue cultivation (reduced herbicide [RH]), while the other system used continuous no-tillage and herbicides to control weeds (standard herbicide [SH]). Research was conducted within the Penn State Sustainable Dairy Cropping Systems Experiment, where corn and soybean are each planted once in a 6-yr crop rotation. In this 3-yr study, weed density and biomass were often greater under RH management, but weed biomass never exceeded 19 g m–2 in corn and 21 g m–2 in soybean. Corn yield and population did not differ in any year, and net returns to management were $33.65 ha–1 higher in RH corn due to lower herbicide costs and slightly, though not significantly, higher yields. Soybean yield was lower in RH compared to SH in 2 of 3 yr, and was correlated with soybean population and cover crop residue. Net financial returns were $43.69 ha–1 higher in SH soybean compared to RH. Predicted soil loss never exceeded T (maximum allowable soil loss) for any treatment and slope combination, though soil loss was 100% greater on a 10% slope under RH management (vs. SH) due to cultivation.
We present a route for direct growth of boron nitride via a polyborazylene to h-BN conversion process. This two-step growth process ultimately leads to a >25x reduction in the root-mean-square surface roughness of h-BN films when compared to a high temperature growth on Al2O3(0001) and Si(111) substrates. Additionally, the stoichiometry is shown to be highly dependent on the initial polyborazylene deposition temperature. Importantly, chemical vapor deposition (CVD) graphene transferred to direct-grown boron nitride films on Al2O3 at 400 °C results in a >1.5x and >2.5x improvement in mobility compared to CVD graphene transferred to Al2O3 and SiO2 substrates, respectively, which is attributed to the combined reduction of remote charged impurity scattering and surface roughness scattering. Simulation of mobility versus carrier concentration confirms the importance of limiting the introduction of charged impurities in the h-BN film and highlights the importance of these results in producing optimized h-BN substrates for high performance graphene and TMD devices.
Recent years have seen great interest in the importance of species richness for the functioning and stability of ecological communities (Ives and Carpenter 2007). Empirical examinations of richness effects typically vary the number of species in experimental treatments and measure resulting ecosystem functions such as biomass accumulation or resource uptake (Naeem et al. 2009). Across trophic levels and communities of many types, a clear pattern has emerged from these experiments: community processes (biomass accumulation, resource uptake, etc.) generally become more efficient when more species are present (Hooper et al. 2005; Cardinale et al. 2006). This pattern is generally attributed to resource partitioning among species, where species differ in ecologically significant ways such that they complement one another (Hooper et al. 2005). For example, in English meadow communities multiple plant species coexist, because different plant species exploit different hydrological conditions (Silvertown et al. 1999). The plants that dominate drought-prone areas are different from those that thrive in flood-prone areas and, presumably, total plant biomass is greatest when both plant groups (drought tolerant and flood tolerant) are present.
A remaining challenge is to effectively predict, a priori, the particular species (or groups of species) that will complement one another. One simplifying scheme that has received considerable attention is the lumping of species into ‘functional groups’. In this functional-group approach, species within a group are relatively similar to one another, and considered ecologically redundant, whereas species in different groups are distinct and complementary (Hillebrand and Matthiessen 2009). This approach gained support from studies suggesting that plant species can be classified into such functional groups (grasses, forbs, legumes and woody plants), and that the number of functional groups is a more effective predictor of ecosystem function than species richness (Diaz and Cabido 2001). For example, in savannah grasslands, plant communities that included C3 grasses, C4 grasses, forbs, legumes and woody plants had greater biomass and plant nitrogen accumulation, and reduced light penetration, than those communities lacking one or more of these groups (Tilman et al. 1997). These authors suggested that competition was greater within than between functional groups, consistent with niche similarity within, but niche differentiation among, groups.
Indentation tests were performed to assess the influence of compositional changes on the mechanical properties of several half-Heusler compounds with the general composition Zr0.5Hf0.5Co1-xIrxSb0.99Sn0.01 (x=0.0,0.1,0.3,0.5,0.7). These samples were synthesized by high temperature solid-state reactions and were consolidated by hot-pressing. Indentation measurements were obtained using both microhardness testing (Vickers) and depth-sensing nanoindentation. These measurements were used to determine the microhardness and the elastic modulus of each half-Heusler compound. The Vickers hardness values were found to range between 876 and 964. A slight increase in hardness was observed with the addition of iridium. The elastic stiffness values ranged from 229 GPa to 246 GPa. Here, a slight decrease in stiffness was observed with the addition of iridium.
Agricultural monocultures are often thought to be more prone to herbivore outbreaks than natural systems, and early agroecologists posited that the lack of biodiversity in agricultural systems contributes to their instability (Pimentel, 1961; van Emden & Williams, 1974). In contrast, some detailed reviews have concluded that perhaps one or two particularly effective natural enemies are all that is needed for effective pest control (Hawkins et al., 1999). Such issues come to the fore when a decision must be made in classical biological control about whether to introduce one or several natural enemy species in an effort to control exotic pests (Myers et al., 1989; Denoth et al., 2002), and when designing schemes to conserve indigenous natural enemies by modifying cultural practices (Landis et al., 2000; Tscharntke et al., 2005). Here, we first review the major classes of natural enemies – specialists and generalists – and the traits of each that are likely to contribute to (or detract from) their effectiveness as biological control agents. We then discuss interactions within diverse communities of natural enemies that are likely to affect biological control.
Specialist natural enemies: the best biological control agents?
Biological control practitioners have long debated the question: what are the traits of an effective biological control agent? General consensus seems to focus around a few traits that a successful agent will possess (see Chapter 9).
More than 15 years—nine election cycles—have passed since a comprehensive set of state legislative election data was compiled and made available to researchers and practitioners: the Inter-University Consortium for Political and Social Research's (ICPSR) State Legislative Election Returns in the United States dataset (Study #8907) collected by Malcolm Jewell (Jewell 1991) and containing observations from 1967 to 1988. With this hiatus in mind, we set out at various times initially—in three independent efforts (Berry and Carsey; Niemi, and Powell; Snyder)—to gather legislative election data for all states and elections since 1988. In addition, Berry and Carsey (2005) cleaned the original dataset to make it more accurate and usable; their corrections led to the release of a revised ICPSR dataset (Study #3938). The culmination of these efforts is a dataset containing information about general elections for state legislative seats from 1967 to 2003, now available through ICPSR (Study 21480).