308 research outputs found
A handbook of Nebraska grasses : with illustrated keys for their identification, together with a general account of their structure and economic importance
The true grasses belong to the one family Poaceae, often called Gramineae, and constitute a very well defined natural group of plants. This family comprises upward of 3,000 species distributed among almost 300 genera. From the economic point of view the family is of supreme importance thru the fact that here belong the cereals, which supply a large part of the food of man, and the forage grasses which are so important as feed for our domesticated animals. The genera and species are for the most part separated by artificial charactersâa fact which renders their study and identification extremely difficult even for the expert. The experience of the authors has convinced them that much of this difficulty is to be credited to the keys found in our common manuals. Theoretically a key is intended to assist one in properly identifying a plant, but actually many of the keys, upon close inspection. are found to contain so many vague and contradictory statements that they can be depended upon only by the expert who, on account of his working knowledge, makes slight use of the keys. It occurred to the senior author some years ago that an illustrated key might solve many of these difficulties. An accurate illustration conveys a more definite idea of any particular structure and leaves less room for doubt than any number of words. In fact, the serious and annoying inaccuracies of most keys to the grasses became more and more apparent as the work of preparing the illustrations progressed. The authors are fully convinced that illustrated keys of the type here employed will prove useful in many other groups of plants. The nomenclature here employed is largely that of the seventh edition of Gray\u27s Manualâtho our purpose has not been to insist upon any particular name but to provide means whereby the student can with some certainty attach to any given plant some one name which has been properly authorized. The present key includes most of the species known to occur in Nebraska, tho a few of minor importance and very restricted distribution have been omitted. There are provided also some data on the economic value of certain of the most important species. The illustrations for the grass keys have been drawn expressly for this publication. They are derived in part from actual authentic specimens and in part redrawn in modified form from various manuals and monographs. T he authors have made free use of the manuals, monographs. etc., included in the Bibliography and take this opportunity to commend these publications to the attention of all who wish to learn more of our common grasses. It is hoped that the keys here presented will facilitate the study of the grass flora of Nebraska by farmers and students
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Detrital Zircon Provenance of Mesoproterozoic to Cambrian Arenites in the Western United States and Northwestern Mexico
U-Pb isotopic dating of detrital zircon from supracrustal Proterozoic and Cambrian arenites from the western United States and northern Mexico reveal three main age groups, 1.90 to 1.62 Ga, 1.45 to 1.40 Ga, and 1.2 to 1.0 Ga. Small amounts of zircons with ages of 3.1 to 2.5 Ga, 1.57 Ga, 1.32 Ga, 1.26 Ga, 0.7 Ga, and 0.5 Ga are also present.
Detrital zircons ranging in age from 1.90 to 1.62 Ga and from 1.45 to 1.40 Ga are considered to have been derived from Proterozoic crystalline basement rocks of these known ages, and probably in part from reworked Proterozoic supracrustal sedimentary rocks, of the western United States. The 1.2 to 1.0 Ga detrital zircon ages from California, Arizona, and Sonora are characterized by distinct spikes (1.11 Ga, in particular) in the age-probability plots. These spikes are interpreted to indicate the influx of zircon from major silicic volcanic fields. Igneous rocks such as the Pikes Peak Granite (1.093 Ga) of Colorado, and the Aibo Granite (1.110 Ga) of Sonora, Mexico, may represent the deeply eroded roots of such volcanic fields. Samples from farther north along the Cordilleran margin that contain abundant 1.2â1.0 Ga detrital zircons do not show spikes in the age distribution, but rather ages spread out across the entire 1.2â1.0 Ga range. These age spectra resemble those for detrital zircons from the Grenville province, which is considered their source.
Less common detrital zircons had a variety of sources. Zircons ranging in age from 3.36 to 2.31 Ga were apparently derived from inland parts of the North American continent from Wyoming to Canada. Zircons of about 1.577 Ga are highly unusual and may have had an exotic source; they may have come from Australia and been deposited in North America when Australia and North America were juxtaposed as part of the hypothetical Rodinian supercontinent. Detrital zircon of âŒ1.320 Ga apparently had the same source as that for tuff (1.320 Ga) in the Pioneer Shale of the Apache Group in Arizona. Detrital zircons of about 1.26 Ga in the Apache Group and Troy Quartzite appear to be related to local, approximately coeval volcanic fields. Zircons of about 0.7 Ga may have had a source in igneous rocks related to rifting of the Proterozoic supercontinent of Rodinia, and 0.5 Ga zircons a source in relatively small areas of granitic rocks of this known, or inferred, age in Oklahoma, Texas, New Mexico, and Colorado
Estimation of capture probabilities using generalized estimating equations and mixed effects approaches
Modeling individual heterogeneity in capture probabilities has been one of the most challenging tasks in capture-recapture studies. Heterogeneity in capture probabilities can be modeled as a function of individual covariates, but correlation structure among capture occasions should be taking into account. A proposed generalized estimating equations (GEE) and generalized linear mixed modeling (GLMM) approaches can be used to estimate capture probabilities and population size for capture-recapture closed population models. An example is used for an illustrative application and for comparison with currently used methodology. A simulation study is also conducted to show the performance of the estimation procedures. Our simulation results show that the proposed quasi-likelihood based on GEE approach provides lower SE than partial likelihood based on either generalized linear models (GLM) or GLMM approaches for estimating population size in a closed capture-recapture experiment. Estimator performance is good if a large proportion of individuals are captured. For cases where only a small proportion of individuals are captured, the estimates become unstable, but the GEE approach outperforms the other methods
Clinical value of patient-specific three-dimensional printing of congenital heart disease: Quantitative and qualitative assessments
Objective: Current diagnostic assessment tools remain suboptimal in demonstrating complex morphology of congenital heart disease (CHD). This limitation has posed several challenges in preoperative planning, communication in medical practice, and medical education. This study aims to investigate the dimensional accuracy and the clinical value of 3D printed model of CHD in the above three areas. Methods: Using cardiac computed tomography angiography (CCTA) data, a patient-specific 3D model of a 20-month-old boy with double outlet right ventricle was printed in Tango Plus material. Pearson correlation coefficient was used to evaluate correlation of the quantitative measurements taken at analogous anatomical locations between the CCTA images pre- and post-3D printing. Qualitative analysis was conducted by distributing surveys to six health professionals (two radiologists, two cardiologists and two cardiac surgeons) and three medical academics to assess the clinical value of the 3D printed model in these three areas. Results: Excellent correlation (r = 0.99) was noted in the measurements between CCTA and 3D printed model, with a mean difference of 0.23 mm. Four out of six health professionals found the model to be useful in facilitating preoperative planning, while all of them thought that the model would be invaluable in enhancing patient-doctor communication. All three medical academics found the model to be helpful in teaching, and thought that the students will be able to learn the pathology quicker with better understanding. Conclusion: The complex cardiac anatomy can be accurately replicated in flexible material using 3D printing technology. 3D printed heart models could serve as an excellent tool in facilitating preoperative planning, communication in medical practice, and medical education, although further studies with inclusion of more clinical cases are needed
Review of Community Pharmacy Staff Educational Needs for Supporting Mental Health Consumers and Carers
Development of a mental health education package for community pharmacy staff should be informed by mental health consumers/carersâ needs, expectations and experiences, and staff knowledge, skills and attitudes. This review (1) explored research on community pharmacy practice and service provision for mental health consumers/carers, and (2) identified validated methods for assessing staff knowledge, skills and attitudes about mental illness to inform the development of a training questionnaire. A literature scan using key words knowledge, skills, attitudes, and beliefs combined with community pharmacy, pharmacist, and pharmacy support staff, and mental illness, depression, anxiety was conducted. A small number of studies were found that used reliable methods to assess pharmacistsâ training needs regarding mental illness and treatment options. There was little published specifically in relation to depression and anxiety in community pharmacy practice. No studies assessed the training needs of pharmacy support staff. A systematic analysis of pharmacy staff learning needs is warranted
nuSTORM - Neutrinos from STORed Muons: Proposal to the Fermilab PAC
The nuSTORM facility has been designed to deliver beams of electron neutrinos
and muon neutrinos (and their anti-particles) from the decay of a stored muon
beam with a central momentum of 3.8 GeV/c and a momentum acceptance of 10%. The
facility is unique in that it will: 1. Allow searches for sterile neutrinos of
exquisite sensitivity to be carried out; 2. Serve future long- and
short-baseline neutrino-oscillation programs by providing definitive
measurements of electron neutrino and muon neutrino scattering cross sections
off nuclei with percent-level precision; and 3. Constitutes the crucial first
step in the development of muon accelerators as a powerful new technique for
particle physics. The document describes the facility in detail and
demonstrates its physics capabilities. This document was submitted to the
Fermilab Physics Advisory Committee in consideration for Stage I approval
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
Destruction of Lymphoid Organ Architecture and Hepatitis Caused by CD4+ T Cells
Immune responses have the important function of host defense and protection against pathogens. However, the immune response also causes inflammation and host tissue injury, termed immunopathology. For example, hepatitis B and C virus infection in humans cause immunopathological sequel with destruction of liver cells by the host's own immune response. Similarly, after infection with lymphocytic choriomeningitis virus (LCMV) in mice, the adaptive immune response causes liver cell damage, choriomeningitis and destruction of lymphoid organ architecture. The immunopathological sequel during LCMV infection has been attributed to cytotoxic CD8+ T cells. However, we now show that during LCMV infection CD4+ T cells selectively induced the destruction of splenic marginal zone and caused liver cell damage with elevated serum alanin-transferase (ALT) levels. The destruction of the splenic marginal zone by CD4+ T cells included the reduction of marginal zone B cells, marginal zone macrophages and marginal zone metallophilic macrophages. Functionally, this resulted in an impaired production of neutralizing antibodies against LCMV. Furthermore, CD4+ T cells reduced B cells with an IgMhighIgDlow phenotype (transitional stage 1 and 2, marginal zone B cells), whereas other B cell subtypes such as follicular type 1 and 2 and germinal center/memory B cells were not affected. Adoptive transfer of CD4+ T cells lacking different important effector cytokines and cytolytic pathways such as IFNγ, TNFα, perforin and Fas-FasL interaction did reveal that these cytolytic pathways are redundant in the induction of immunopathological sequel in spleen. In conclusion, our results define an important role of CD4+ T cells in the induction of immunopathology in liver and spleen. This includes the CD4+ T cell mediated destruction of the splenic marginal zone with consecutively impaired protective neutralizing antibody responses
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