809 research outputs found
The Effects of Higher and Lower CO2 Levels in the Atmosphere on the Photosynthetic Rates and Stomatal Conductance of Malosma laurina in The Santa Monica Mountains
We hypothesize that higher CO2 levels will lead to a change in photosynthetic performance in the Malosma laurina population of the Santa Monica Mountains. We used one Malosma laurina that is across the street from university’s theme tower. We chose this specific plant because it was in the sun and it was in a well irrigated area. We selected a plant that is in non-shaded areas at 12:00 pm and then dark adapt them for 20 minutes. We selected an adult plant that was between four and six feet tall. We took the measurements from the upper leaves of the plant. We measured the photosynthetic rates of the plant, which will be exposed to the unaltered CO2 levels of the natural environment in the Santa Monica Mountains. Then, we used the LICOR (Li- 6400) system to create create three separate environments that we will then impose on the same plant but using different leaves. These simulated environments will have CO2 levels of 280ppm (past atmospheric level of CO2 before the industrial revolution), 400ppm (current atmospheric level of CO2), and 800ppm (expected atmospheric level of CO2 by 2100)
Slow acid production by butter cultures
Butter cultures sometimes fail to develop acid at a normal rate, and such slow growth has probably been encountered wherever butter cultures are used.
One characteristic of certain types of abnormally slow growth in butter cultures is the sudden manner in which the defect often occurs. A culture may appear satisfactory at the time it is used for inoculation and then fail to bring about the desired changes in the product being manufactured. Such an occurrence greatly interferes with general plant routine. If additional time is allowed for the formation of acid, a defective product may result. Sometimes acid development is so slow and the defects in the product being manufactured so serious that the finished material is unsalable.
There are various causes of slow acid production by butter cultures. Some of these are easily determined by investigation of the methods used in propagation or by direct microscopic examination of the cultures. In other cases such methods fail to disclose the cause or causes of the abnormally slow growth, and the rather unusual aspects of such cases have motivated the work herein reported
Hadronic production and the Gottfried Sum Rule
The difference in production rate between and at hadron colliders
is very sensitive to the the difference between up- and down-quark
distributions in the proton. This sensitivity allows for a variety of useful
measurements. We consider the difference in the sea
distributions and the difference in the
polarized parton distribution functions. In both cases we construct an
asymmetry to reduce systematic uncertainties. Although we discuss measurements
at the Tevatron and future hadron colliders, we find that the Brookhaven
Relativistic Heavy Ion Collider (RHIC) is the most appropriate hadron collider
for these measurements.Comment: 19 pages (20 figures available from the authors), MAD/PH/74
Constraint-based, Single-point Approximate Kinetic Energy Functionals
We present a substantial extension of our constraint-based approach for
development of orbital-free (OF) kinetic-energy (KE) density functionals
intended for the calculation of quantum-mechanical forces in multi-scale
molecular dynamics simulations. Suitability for realistic system simulations
requires that the OF-KE functional yield accurate forces on the nuclei yet be
relatively simple. We therefore require that the functionals be based on DFT
constraints, local, dependent upon a small number of parameters fitted to a
training set of limited size, and applicable beyond the scope of the training
set. Our previous "modified conjoint" generalized-gradient-type functionals
were constrained to producing a positive-definite Pauli potential. Though
distinctly better than several published GGA-type functionals in that they gave
semi-quantitative agreement with Born-Oppenheimer forces from full Kohn-Sham
results, those modified conjoint functionals suffer from unphysical
singularities at the nuclei. Here we show how to remove such singularities by
introducing higher-order density derivatives. We give a simple illustration of
such a functional used for the dissociation energy as a function of bond length
for selected molecules.Comment: 16 pages, 9 figures, 2 tables, submitted to Phys. Rev.
Symmetric Informationally Complete Measurements of Arbitrary Rank
There has been much interest in so-called SIC-POVMs: rank 1 symmetric
informationally complete positive operator valued measures. In this paper we
discuss the larger class of POVMs which are symmetric and informationally
complete but not necessarily rank 1. This class of POVMs is of some independent
interest. In particular it includes a POVM which is closely related to the
discrete Wigner function. However, it is interesting mainly because of the
light it casts on the problem of constructing rank 1 symmetric informationally
complete POVMs. In this connection we derive an extremal condition alternative
to the one derived by Renes et al.Comment: Contribution to proceedings of International Conference on Quantum
Optics, Minsk, 200
Hadron collider limits on anomalous couplings
A next-to-leading log calculation of the reactions and
is presented including a tri-boson
gauge coupling from non-Standard Model contributions. Two approaches are made
for comparison. The first approach considers the tri-boson coupling
as being uniquely fixed by tree level unitarity at high energies to its
Standard Model form and, consequently, suppresses the non-Standard Model
contributions with form factors. The second approach is to ignore such
considerations and calculate the contributions to non-Standard Model tri-boson
gauge couplings without such suppressions. It is found that at Tevatron
energies, the two approaches do not differ much in quantitative results, while
at Large Hadron Collider (LHC) energies the two approaches give significantly
different predictions for production rates. At the Tevatron and LHC, however,
the sensitivity limits on the anomalous coupling of are too weak to
usefully constrain parameters in effective Lagrangian models.Comment: Revtex 23 pages + 8 figures, UIOWA-94-1
Searching for in t \tbar Production
The triple gluon field strength operator represents the only genuinely
gluonic CP conserving term which can appear at dimension-6 within an effective
strong interaction Lagrangian. Previous studies of this operator have revealed
that its effect on gluon scattering is surprisingly difficult to detect. In
this article, we analyze the impact of upon top quark pair production. We
find that it will generate observable cross section deviations from QCD at the
LHC for even relatively small values of its coefficient. Furthermore,
affects the transverse momentum distribution of the produced top quarks more
strongly at high energies than dimension-6 four-quark and chromomagnetic moment
terms in the effective Lagrangian. Top-antitop production at the LHC will
therefore provide a sensitive and clean probe for the elusive triple gluon
field strength operator.Comment: 20 pages, 8 figures (3 updated figures not included but available
upon request), CALT-68-1941, BUHEP-94-18. (Some previously overlooked graphs
are now included. Our conclusions remain unchanged.
Enhancing the top signal at Tevatron using Neural Nets
We show that Neural Nets can be useful for top analysis at Tevatron. The main
features of and background events on a mixed sample are projected in
a single output, which controls the efficiency and purity of the
signal.Comment: 11 pages, 6 figures (not included and available from the authors),
Latex, UB-ECM-PF 94/1
Multiparton interactions and production of minijets in high energy hadronic collisions
We discuss the inclusive cross section to produce two minijets with a large
separation in rapidity in high energy hadronic collisions. The contribution to
the inclusive cross section from the exchange of a BFKL Pomeron is compared
with the contribution from the exchange of two BFKL Pomerons, which is induced
by the unitarization of the semi-hard interaction. The effect of the multiple
exchange is studied both as a function of the azimuthal correlation and as a
function of the transverse momentum of the observed minijets.Comment: TeX file, 20 pages, 4 figures available on reques
Z' Decays into Four Fermions
If a new is discovered with a mass at LHC/SSC, its (rare)
decays into two charged leptons plus missing transverse energy will probe the
coupling to the lepton doublet and to , allowing
further discrimination among extended electroweak models.Comment: 9 pages plus 1 figure (not included but available), UG-FT-22/9
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