244 research outputs found
Taxonomy and paleobiology of some Middle Cambrian Scenella (Cnidaria) and Hyolithids (Mollusca) from western North America
22 p., 10 fig.http://paleo.ku.edu/contributions.htm
Systematics, paleobiology, and taphonomy of some exceptionally preserved trilobites from Cambrian Lagerstätten of Utah
Mid-Cambrian biotas of the Spence, Wheeler, Marjum, and Weeks formations in Utah are exceptionally diverse. Continued collecting has produced additional trilobites here assigned to one new genus, Meniscopsia, and 25 new species. The new species, all known from complete or nearly complete dorsal exoskeletons, are Amecephalus jamisoni, Athabaskia gladei, Bolaspidella jarrardi, Bolaspidella reesae, Burlingia halgedahlae, Coosella kieri, Ehmaniella whitei, Glossopleura campbelli, Glossopleura yatesi, Ithycephalus stricklandi, Kootenia randolphi, Kootenia youngorum, Meniscopsia beebei, Menomonia sahratiani, Modocia comforti, Modocia kohli, Modocia whiteleyi, Norwoodia boninoi, Olenoides skabelundi, Olenoides vali, Polypleuraspis cooperi, Ptychoparella lloydi, Ptychoparella mettae, Zacanthoides liddelli, and Zacanthoides marshalli. Descriptions of two other species, Triadaspis bigeneris and Zacanthoides typicalis, are expanded to include new information from complete dorsal exoskeletons. The ventral cephalic presence of a functional rostral-hypostomal suture in the corynexochoid Zacanthoides marshalli further demonstrates that a fused rostral-hypostomal plate is not a unique defining character of the order Corynexochida, adding to evidence that the Corynexochida may be a polyphyletic taxon. The ventral cephalic presence of a median suture, associated with a rostellum in Norwoodia boninoi, order Ptychopariida, is further evidence for a polyphyletic origin of the median suture, previously cited as a unique apomorphic character defining the order Asaphida, which needs revision. The presence of a mineralized alimentary tract and digestive glands in some specimens of Meniscopsia beebei and Coosella kieri suggests that the gut was fluid filled at the time of burial and that the species were predaceous. Collapsed glabellas are interpreted as further evidence of fluid-filled gut tracts in some of the new species. Many of the articulated trilobites preserved in mid-Cambrian Lagerstätten of Utah were probably buried under rapidly deposited sediment clouds on a storm-prone marine shelf. Occasionally, trilobite clusters were buried. Encrustation of fully articulated individuals with calcitic cone-in-cone deposits in the Wheeler and Marjum formations is a likely consequence of concretionary-type growth within a biofilm shortly after death
Parent Agreement on Ratings of Children's Attention Deficit/Hyperactivity Disorder and Broadband Externalizing Behaviors
Mothers and fathers often disagree in their ratings of child behavior, as evidenced clinically and as supported
by a substantial literature examining parental agreement on broadband rating scales. The present study
examined mother-father agreement on Diagnostic and Statistical Manual-based symptom-specific ratings
of Attention-Deficit/Hyperactivity Disorder (ADHD), as compared to agreement on broadband ratings of
externalizing behavior. Based on mother and father ratings of 324 children who participated in the
Multimodal Treatment Study of Children with ADHD (MTA), parental agreement was computed and
patterns of disagreement examined. Mother-father ratings were significantly correlated; however, a clear
pattern of higher ratings by mothers was present. Agreement on attention-deficit/hyperactivity disorder
symptom-specific ratings was significantly lower than that for broadband externalizing behaviors and
oppositional defiant disorder symptoms. Of several moderator variables tested, parental stress was the only
one that predicted the discrepancy in ratings. Disagreement between parents is clinically significant and may
pose complications to the diagnostic process
Exports and Productivity: Comparable Evidence for 14 Countries
We use comparable micro level panel data for 14 countries and a set of identically specified empirical models to investigate the relationship between exports and productivity. Our overall results are in line with the big picture that is by now familiar from the literature: Exporters are more productive than non-exporters when observed and unobserved heterogeneity are controlled for, and these exporter productivity premia tend to increase with the share of exports in total sales; there is strong evidence in favour of self-selection of more productive firms into export markets, but nearly no evidence in favour of the learning-by-exporting hypothesis. We document that the exporter premia differ considerably across countries in identically specified empirical models. In a meta-analysis of our results we find that countries that are more open and have more effective government report higher productivity premia. However, the level of development per se does not appear to be an explanation for the observed cross-country differences.exports; productivity; micro data; international comparison
A global-temporal analysis on Phytophthora sojae resistance-gene efficacy
Plant disease resistance genes are widely used in agriculture to reduce disease outbreaks and epidemics and ensure global food security. In soybean, Rps (Resistance to Phytophthora sojae) genes are used to manage Phytophthora sojae, a major oomycete pathogen that causes Phytophthora stem and root rot (PRR) worldwide. This study aims to identify temporal changes in P. sojae pathotype complexity, diversity, and Rps gene efficacy. Pathotype data was collected from 5121 isolates of P. sojae, derived from 29 surveys conducted between 1990 and 2019 across the United States, Argentina, Canada, and China. This systematic review shows a loss of efficacy of specific Rps genes utilized for disease management and a significant increase in the pathotype diversity of isolates over time. This study finds that the most widely deployed Rps genes used to manage PRR globally, Rps1a, Rps1c and Rps1k, are no longer effective for PRR management in the United States, Argentina, and Canada. This systematic review emphasizes the need to widely introduce new sources of resistance to P. sojae, such as Rps3a, Rps6, or Rps11, into commercial cultivars to effectively manage PRR going forward
Recommended from our members
Experience with targeted next generation sequencing for the care of lung cancer: Insights into promises and limitations of genomic oncology in day-to-day practice
Introduction
Tumor genotyping using single gene assays (SGAs) is standard practice in advanced non-small-cell lung cancer (NSCLC). We evaluated how the introduction of next generation sequencing (NGS) into day-to-day clinical practice altered therapeutic decision-making.
Methods
Clinicopathologic data, tumor genotype, and clinical decisions were retrospectively compiled over 6 months following introduction of NGS assay use at our institution in 82 patient-tumor samples (7 by primary NGS, 22 by sequential SGAs followed by NGS, and 53 by SGAs).
Results
SGAs identified abnormalities in 34 samples, and all patients with advanced EGFR-mutated or ALK-rearranged tumors received approved tyrosine kinase inhibitors (TKIs) or were consented for clinical trials. NGS was more commonly requested for EGFR, ALK, and KRAS-negative tumors (p<0.0001). NGS was successful in 24/29 (82.7%) tumors. Of 17 adenocarcinomas (ACs), 11 (7 from patients with ≤15 pack-years of smoking) had abnormalities in a known driver oncogene. This led to a change in decision-making in 8 patients, trial consideration in 6, and off-label TKI use in 2. Of 7 squamous cell (SC) carcinomas, 1 had a driver aberration (FGFR1); 6 had other genomic events (all with TP53 mutations). In no cases were clinical decisions altered (p=0.0538 when compared to ACs).
Conclusions
Targeted NGS can identify a significant number of therapeutically-relevant driver events in lung ACs; particularly in never or light smokers. For SC lung cancers, NGS is less likely to alter current practice. Further research into the cost effectiveness and optimal use of NGS and improved provider training in genomic oncology are warranted
Room Temperature Optically and Magnetically Active Edges in Phosphorene Nanoribbons
Nanoribbons - nanometer wide strips of a two-dimensional material - are a
unique system in condensed matter physics. They combine the exotic electronic
structures of low-dimensional materials with an enhanced number of exposed
edges, where phenomena including ultralong spin coherence times, quantum
confinement and topologically protected states can emerge. An exciting prospect
for this new material concept is the potential for both a tunable
semiconducting electronic structure and magnetism along the nanoribbon edge.
This combination of magnetism and semiconducting properties is the first step
in unlocking spin-based electronics such as non-volatile transistors, a route
to low-energy computing, and has thus far typically only been observed in doped
semiconductor systems and/or at low temperatures. Here, we report the magnetic
and semiconducting properties of phosphorene nanoribbons (PNRs). Static (SQUID)
and dynamic (EPR) magnetization probes demonstrate that at room temperature,
films of PNRs exhibit macroscopic magnetic properties, arising from their edge,
with internal fields of ~ 250 to 800 mT. In solution, a giant magnetic
anisotropy enables the alignment of PNRs at modest sub-1T fields. By leveraging
this alignment effect, we discover that upon photoexcitation, energy is rapidly
funneled to a dark-exciton state that is localized to the magnetic edge and
coupled to a symmetry-forbidden edge phonon mode. Our results establish PNRs as
a unique candidate system for studying the interplay of magnetism and
semiconducting ground states at room temperature and provide a stepping-stone
towards using low-dimensional nanomaterials in quantum electronics.Comment: 18 pages, 4 figure
- …