476 research outputs found
Yield prediction by analysis of multispectral scanner data
A preliminary model describing the growth and grain yield of wheat was developed. The modeled growth characteristics of the wheat crop were used to compute wheat canopy reflectance using a model of vegetation canopy reflectance. The modeled reflectance characteristics were compared with the corresponding growth characteristics and grain yield in order to infer their relationships. It appears that periodic wheat canopy reflectance characteristics potentially derivable from earth satellites will be useful in forecasting wheat grain yield
Trapped lipopolysaccharide and LptD intermediates reveal lipopolysaccharide translocation steps across the Escherichia coli outer membrane
Lipopolysaccharide (LPS) is a main component of the outer membrane of Gram-negative bacteria, which is essential for the vitality of most Gram-negative bacteria and plays a critical role for drug resistance. LptD/E complex forms a N-terminal LPS transport slide, a hydrophobic intramembrane hole and the hydrophilic channel of the barrel, for LPS transport, lipid A insertion and core oligosaccharide and O-antigen polysaccharide translocation, respectively. However, there is no direct evidence to confirm that LptD/E transports LPS from the periplasm to the external leaflet of the outer membrane. By replacing LptD residues with an unnatural amino acid p-benzoyl-L-phenyalanine (pBPA) and UV-photo-cross-linking in E.coli, the translocon and LPS intermediates were obtained at the N-terminal domain, the intramembrane hole, the lumenal gate, the lumen of LptD channel, and the extracellular loop 1 and 4, providing the first direct evidence and “snapshots” to reveal LPS translocation steps across the outer membrane
Slater-Pauling Behavior of the Half-Ferromagnetic Full-Heusler Alloys
Using the full-potential screened Korringa-Kohn-Rostoker method we study the
full-Heusler alloys based on Co, Fe, Rh and Ru. We show that many of these
compounds show a half-metallic behavior, however in contrast to the
half-Heusler alloys the energy gap in the minority band is extremely small.
These full-Heusler compounds show a Slater-Pauling behavior and the total
spin-magnetic moment per unit cell (M_t) scales with the total number of
valence electrons (Z_t) following the rule: M_t=Z_t-24. We explain why the
spin-down band contains exactly 12 electrons using arguments based on the group
theory and show that this rule holds also for compounds with less than 24
valence electrons. Finally we discuss the deviations from this rule and the
differences compared to the half-Heusler alloys.Comment: 10 pages, 8 figures, revised figure 3, new text adde
Half-metallicity and Slater-Pauling behavior in the ferromagnetic Heusler alloys
Introductory chapter for the book "Halfmetallic Alloys - Fundamentals and
Applications" to be published in the series Springer Lecture Notes on Physics,
P. H. Dederichs and I. Galanakis (eds). It contains a review of the theoretical
work on the half-metallic Heusler alloys.Comment: Introductory chapter for the book "Halfmetallic Alloys - Fundamentals
and Applications" to be published in the series Springer Lecture Notes on
Physics, P. H. Dederichs and I. Galanakis (eds
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What Happened to the Bondholding Class? Public Debt, Power and the Top One Per Cent
In 1887 Henry Carter Adams produced a study demonstrating that the ownership of government bonds was heavily concentrated in the hands of a ‘bondholding class’ that lent to and, in Adams's view, controlled the government like dominant shareholders control a corporation. The interests of this bondholding class clashed with the interests of the masses, whose burdensome taxes financed the interest payments on government bonds. Since the late nineteenth century there has been plenty of debate about the ownership of the public debt. But the empirical evidence offered to support the various arguments has been scant. As a result, political economists have few answers to questions first raised by Adams over century ago: how has the pattern of public debt ownership changed? Can we still speak of a powerful ‘bondholding class’? Does public debt redistribute income from taxpayers to public creditors? This article develops a new framework to address these questions. Anchored within a ‘capital as power’ approach, the research indicates a staggering pattern of concentration in the ownership of US public debt in the hands of the top one per cent of US households over the past three decades. Accordingly, the bondholding class is still alive and well in contemporary US capitalism
The role of normally hyperbolic invariant manifolds (NHIMS) in the context of the phase space setting for chemical reaction dynamics
Pannexin 1 regulates postnatal neural stem and progenitor cell proliferation
<p>Abstract</p> <p>Background</p> <p>Pannexin 1 forms ion and metabolite permeable hexameric channels and is abundantly expressed in the brain. After discovering pannexin 1 expression in postnatal neural stem and progenitor cells we sought to elucidate its functional role in neuronal development.</p> <p>Results</p> <p>We detected pannexin 1 in neural stem and progenitor cells <it>in vitro</it> and <it>in vivo</it>. We manipulated pannexin 1 expression and activity in Neuro2a neuroblastoma cells and primary postnatal neurosphere cultures to demonstrate that pannexin 1 regulates neural stem and progenitor cell proliferation likely through the release of adenosine triphosphate (ATP).</p> <p>Conclusions</p> <p>Permeable to ATP, a potent autocrine/paracine signaling metabolite, pannexin 1 channels are ideally suited to influence the behavior of neural stem and progenitor cells. Here we demonstrate they play a robust role in the regulation of neural stem and progenitor cell proliferation. Endogenous postnatal neural stem and progenitor cells are crucial for normal brain health, and their numbers decline with age. Furthermore, these special cells are highly responsive to neurological injury and disease, and are gaining attention as putative targets for brain repair. Therefore, understanding the fundamental role of pannexin 1 channels in neural stem and progenitor cells is of critical importance for brain health and disease.</p
Play and games:An opinionated introduction
Philosophy has a schizophrenic relationship with games. On the one hand, philosophers love using games as model, arguing that phenomena as diverse as linguistic meaning, meta‐ethics, normative ethics, applied ethics, law, and aesthetics can be illuminated via an analogy with games. On the other hand, there is scant focused discussion of the concept of a game as such. This is problematic; the appeal to games as a model to clarify philosophically puzzling questions has limited utility if games themselves (and the concept of a game) are poorly understood. Moreover, playing games plausibly is an important element in a good life; anyone interested in the theory of welfare, a traditional philosophical topic, should be interested in games. We play games, but if anything, play itself has been more neglected by philosophers than games. This neglect is unwarranted. Historically, philosophy has investigated foundational questions about human nature, and a disposition to play plausibly is a deep part of human nature. Moreover, play is an important concept in evolutionary biology and psychology, yet those working in those fields struggle to define the concept to their own satisfaction. E.O. Wilson went so far as to remark that “no behavioural concept has proved more ill‐defined, elusive, controversial, and even unfashionable than play.” One might have hoped philosophers could help here. In this paper, I provide an opinionated introduction to the philosophy of play and games.Some time ago, an innocent bystander, after glancing through a copy of Mind, asked me, ‘Why do philosophers talk so much about games? Do they play them a lot or something?’ (Midgley, 1974: 321
Action theory and the value of sport
I present a corrective to the formalist and conventionalist down-playing of physical actions in the understanding of the value of sport. I give a necessarily brief account of the Causal Theory of Action (CTA) and its implications for the normativity of actions. I show that the CTA has limitations, particularly in the case of failed or incomplete actions, and I show that failed or incomplete actions are constitutive of sport. This allows me to open up the space for another model, drawn from Aristotle, for failed or incomplete actions, conceived of as ‘doables’. This avoids some of the problems of the CTA. I explain the importance of difficult but doable actions, at which athletes often fail, and suggest that this establishes pro tanto value. Finally, I claim that this account of the actions that are constitutive of sport deepens our understanding of the value of sport as a whole
A Rapid Host-protein Test for Differentiating Bacterial From Viral Infection: Apollo Diagnostic Accuracy Study
OBJECTIVES: To determine the diagnostic accuracy of a rapid host-protein test for differentiating bacterial from viral infections in patients who presented to the emergency department (ED) or urgent care center (UCC).
METHODS: This was a prospective multicenter, blinded study. MeMed BV (MMBV), a test based on tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), interferon gamma-inducible protein-10 (IP-10), and C-reactive protein (CRP), was measured using a rapid measurement platform. Patients were enrolled from 9 EDs and 3 UCCs in the United States and Israel. Patients \u3e3 months of age presenting with fever and clinical suspicion of acute infection were considered eligible. MMBV results were not provided to the treating clinician. MMBV results (bacterial/viral/equivocal) were compared against a reference standard method for classification of infection etiology determined by expert panel adjudication. Experts were blinded to MMBV results. They were provided with comprehensive patient data, including laboratory, microbiological, radiological and follow-up.
RESULTS: Of 563 adults and children enrolled, 476 comprised the study population (314 adults, 162 children). The predominant clinical syndrome was respiratory tract infection (60.5% upper, 11.3% lower). MMBV demonstrated sensitivity of 90.0% (95% confidence interval [CI]: 80.3-99.7), specificity of 92.8% (90.0%-95.5%), and negative predictive value of 98.8% (96.8%-99.6%) for bacterial infections. Only 7.2% of cases yielded equivocal MMBV scores. Area under the curve for MMBV was 0.95 (0.90-0.99).
CONCLUSIONS: MMBV had a high sensitivity and specificity relative to reference standard for differentiating bacterial from viral infections. Future implementation of MMBV for patients with suspected acute infections could potentially aid with appropriate antibiotic decision-making
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