520 research outputs found
Efficacy of Hibiscus Cannabinus L. (kenaf) Crude Seed Powder and its Methanol Extract in Water Purification
The efficiencies of hibiscus cannabinus (kenaf) powder and methanol extract were studied in water purification. Two turbidity levels namely, high (160NTU) and low (49NTU) were considered. The water samples were taken from an open pond used for irrigation farming in Custom area of Maiduguri, Nigeria. In this study, the powdered cannabinus was discovered to be more effective in removing high turbidity water, with an efficiency of 96.0% against the extract with 85.6%. However, in low turbidity water, the methanol extract performed better, with a turbidity removal efficiency of 89.4% compared to 84.4%, if the cannabinus powder is used. Another parameter studied was the pH of the water which remains unaffected after the treatment at 7.0. The outcome of the performance of this natural coagulant and alum when compared indicated that alum also performed better on high turbidity water than low turbid water with a removal efficiency of 98.8% and 95.7% respectively. Alum slightly affected the pH of the water from original value of 7.0 to 5.5, which makes the water more acidic after treatment. It appears that natural coagulants of plant origin remain the best option engineers are left with, if the current emphasis on millennium development goal on clean water supply for all is to be achieved. Keywords: , Cannabinus, Coagulation, Water Purificatio
Implicit complexity for coinductive data: a characterization of corecurrence
We propose a framework for reasoning about programs that manipulate
coinductive data as well as inductive data. Our approach is based on using
equational programs, which support a seamless combination of computation and
reasoning, and using productivity (fairness) as the fundamental assertion,
rather than bi-simulation. The latter is expressible in terms of the former. As
an application to this framework, we give an implicit characterization of
corecurrence: a function is definable using corecurrence iff its productivity
is provable using coinduction for formulas in which data-predicates do not
occur negatively. This is an analog, albeit in weaker form, of a
characterization of recurrence (i.e. primitive recursion) in [Leivant, Unipolar
induction, TCS 318, 2004].Comment: In Proceedings DICE 2011, arXiv:1201.034
Occupation and mental health in a national UK survey
This paper and the analyses it describes were funded by the
Health and Safety Executive (HSE)
Itinerant Electron Ferromagnetism in the Quantum Hall Regime
We report on a study of the temperature and Zeeman-coupling-strength
dependence of the one-particle Green's function of a two-dimensional (2D)
electron gas at Landau level filling factor where the ground state is
a strong ferromagnet. Our work places emphasis on the role played by the
itinerancy of the electrons, which carry the spin magnetization and on
analogies between this system and conventional itinerant electron ferromagnets.
We discuss the application to this system of the self-consistent Hartree-Fock
approximation, which is analogous to the band theory description of metallic
ferromagnetism and fails badly at finite temperatures because it does not
account for spin-wave excitations. We go beyond this level by evaluating the
one-particle Green's function using a self-energy, which accounts for
quasiparticle spin-wave interactions. We report results for the temperature
dependence of the spin magnetization, the nuclear spin relaxation rate, and
2D-2D tunneling conductances. Our calculations predict a sharp peak in the
tunneling conductance at large bias voltages with strength proportional to
temperature. We compare with experiment, where available, and with predictions
based on numerical exact diagonalization and other theoretical approaches.Comment: 29 pages, 20 figure
Ernst Freund as Precursor of the Rational Study of Corporate Law
Gindis, David, Ernst Freund as Precursor of the Rational Study of Corporate Law (October 27, 2017). Journal of Institutional Economics, Forthcoming. Available at SSRN: https://ssrn.com/abstract=2905547, doi: https://dx.doi.org/10.2139/ssrn.2905547The rise of large business corporations in the late 19th century compelled many American observers to admit that the nature of the corporation had yet to be understood. Published in this context, Ernst Freund's little-known The Legal Nature of Corporations (1897) was an original attempt to come to terms with a new legal and economic reality. But it can also be described, to paraphrase Oliver Wendell Holmes, as the earliest example of the rational study of corporate law. The paper shows that Freund had the intuitions of an institutional economist, and engaged in what today would be called comparative institutional analysis. Remarkably, his argument that the corporate form secures property against insider defection and against outsiders anticipated recent work on entity shielding and capital lock-in, and can be read as an early contribution to what today would be called the theory of the firm.Peer reviewe
Trial outcomes and information for clinical decision-making: a comparative study of opinions of health professionals
Background: Trials are robust sources of data for clinical practice, however, trial outcomes may not reflect what is important to communicate for decision making. The study compared clinicians’ views of outcomes to include in a core outcome set for colorectal cancer (CRC) surgery, with what clinicians considered important information for clinical practice (core information). Methods: Potential outcomes/information domains were identified through systematic literature reviews, reviews of hospital information leaflets and interviews with patients. These were organized into 6 categories, and used to design a questionnaire survey that asked surgeons and nurses from a sample of CRC centers to rate the importance of each domain as an outcome or as information on a 9-point Likert scale. Respondents were re-surveyed (round 2) following group feedback (Delphi methods). Comparisons were made by calculating the difference in mean scores between the outcomes and information domains, and paired t-tests were used to explore the difference between mean scores of the 6 outcome/information categories. Results: Data sources identified 1216 outcomes/information of CRC surgery that informed a 94 item questionnaire. First round questionnaires were returned from 63/81 (78%) of centers. Clinicians rated 76/94 (84%) domains of higher importance to measure in trials than to information to communicate to patients in Round 1. This was reduced to 24/47 (51%) in Round 2. The greatest difference was evident in domains about survival, which was rated much more highly as a trial outcome than important piece of information for decision-making (mean difference 2.3, 95% CI 1.9-2.8, p<0.0001). Specific complications and quality-of-life domains were rated similarly (mean difference 0.18, 95% CI -0.1-0.4, p=0.2 and 0.2, 95% CI -0.1-0.5, p=0.2 respectively). Conclusions: Whilst clinicians want to measure key outcomes in trials, they rate these as less important to communicate in decision-making with patients. This discrepancy needs to be explored and addressed to maximize the impact of trials on clinical practice
Transverse energy production and charged-particle multiplicity at midrapidity in various systems from to 200 GeV
Measurements of midrapidity charged particle multiplicity distributions,
, and midrapidity transverse-energy distributions,
, are presented for a variety of collision systems and energies.
Included are distributions for AuAu collisions at ,
130, 62.4, 39, 27, 19.6, 14.5, and 7.7 GeV, CuCu collisions at
and 62.4 GeV, CuAu collisions at
GeV, UU collisions at GeV,
Au collisions at GeV, HeAu collisions at
GeV, and collisions at
GeV. Centrality-dependent distributions at midrapidity are presented in terms
of the number of nucleon participants, , and the number of
constituent quark participants, . For all collisions
down to GeV, it is observed that the midrapidity data
are better described by scaling with than scaling with . Also presented are estimates of the Bjorken energy density,
, and the ratio of to ,
the latter of which is seen to be constant as a function of centrality for all
systems.Comment: 706 authors, 32 pages, 20 figures, 34 tables, 2004, 2005, 2008, 2010,
2011, and 2012 data. v2 is version accepted for publication in Phys. Rev.
meson production in Au collisions at GeV
The PHENIX experiment has measured meson production in Au
collisions at GeV using the dimuon and dielectron decay
channels. The meson is measured in the forward (backward) -going
(Au-going) direction, () in the transverse-momentum
() range from 1--7 GeV/, and at midrapidity in the
range below 7 GeV/. The meson invariant yields and
nuclear-modification factors as a function of , rapidity, and centrality
are reported. An enhancement of meson production is observed in the
Au-going direction, while suppression is seen in the -going direction, and
no modification is observed at midrapidity relative to the yield in
collisions scaled by the number of binary collisions. Similar behavior was
previously observed for inclusive charged hadrons and open heavy flavor
indicating similar cold-nuclear-matter effects.Comment: 484 authors, 16 pages, 12 figures, 6 tables. v1 is the version
accepted for publication in Phys. Rev. C. Data tables for the points plotted
in the figures are given in the paper itsel
Cross Section and Transverse Single-Spin Asymmetry of Mesons in Collisions at GeV at Forward Rapidity
We present a measurement of the cross section and transverse single-spin
asymmetry () for mesons at large pseudorapidity from
~GeV collisions. The measured cross section for
~GeV/ and is well described by a
next-to-leading-order perturbative-quantum-chromodynamics calculation. The
asymmetries have been measured as a function of Feynman- () from
, as well as transverse momentum () from
~GeV/. The asymmetry averaged over positive is
. The results are consistent with prior
transverse single-spin measurements of forward and mesons at
various energies in overlapping ranges. Comparison of different particle
species can help to determine the origin of the large observed asymmetries in
collisions.Comment: 484 authors, 13 pages, 11 figures, 4 tables, 2008 data. v2 is version
accepted by Phys. Rev. D. Plain text data tables for the points plotted in
figures for this and previous PHENIX publications are (or will be)publicly
available at http://www.phenix.bnl.gov/papers.htm
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