1,690 research outputs found
Critical loads for nutrient nitrogen for soil-vegetation systems
Members of the UK Critical Loads Advisory Group (CLAG) have calculated critical loads for nutrient nitrogen to produce maps for Great Britain. The results of three methods, based upon the conclusions from the Lokeberg workshop are described below. Two of these methods use the empirical approachand the other the steady state equation ("mass balance") for nitrogen saturation
Gavestinel does not improve outcome after acute intracerebral hemorrhage: an analysis from the GAIN International and GAIN Americas studies
<p><b>Background and Purpose:</b> Glycine Antagonist in Neuroprotection (GAIN) International and GAIN Americas trials were prospectively designed, randomized, placebo-controlled trials of gavestinel, a glycine-site antagonist and putative neuroprotectant drug administered within 6 hours of suspected ischemic or hemorrhagic stroke. Both trials reported that gavestinel was ineffective in ischemic stroke. This analysis reports the results in those with primary intracerebral hemorrhage.</p>
<p><b>Methods:</b> The primary hypothesis was that gavestinel treatment did not alter outcome, measured at 3 months by the Barthel Index (BI), from acute intracerebral hemorrhage, based on pooled results from both trials. The BI scores were divided into 3 groups: 95 to 100 (independent), 60 to 90 (assisted independence), and 0 to 55 (dependent) or dead.</p>
<p><b>Results:</b> In total, 3450 patients were randomized in GAIN International (N=1804) and GAIN Americas (N=1646). Of these, 571 were ultimately identified to have spontaneous intracerebral hematoma on baseline head computerized tomography scan. The difference in distribution of trichotomized BI scores at 3 months between gavestinel and placebo was not statistically significant (P=0.09). Serious adverse events were reported at similar rates in the 2 treatment groups.</p>
<p><b>Conclusions:</b> These observations from the combined GAIN International and GAIN Americas trials suggest that gavestinel is not of substantial benefit or harm to patients with primary intracerebral hemorrhage. These findings are similar to results previously reported in patients with ischemic stroke.</p>
Entropy and the variational principle for actions of sofic groups
Recently Lewis Bowen introduced a notion of entropy for measure-preserving
actions of a countable sofic group on a standard probability space admitting a
generating partition with finite entropy. By applying an operator algebra
perspective we develop a more general approach to sofic entropy which produces
both measure and topological dynamical invariants, and we establish the
variational principle in this context. In the case of residually finite groups
we use the variational principle to compute the topological entropy of
principal algebraic actions whose defining group ring element is invertible in
the full group C*-algebra.Comment: 44 pages; minor changes; to appear in Invent. Mat
Laboratory simulation of cometary x rays using a high-resolution microcalorimeter
X-ray emission following charge exchange has been studied on the University
of California Lawrence Livermore National Laboratory electron beam ion traps
EBIT-I and EBIT-II using a high-resolution microcalorimeter. The measured
spectra include the K-shell emission from hydrogenlike and heliumlike C, N, O,
and Ne needed for simulations of cometary x-ray emission. A comparison of the
spectra produced in the interaction of O8+ with N2 and CH4 is presented that
illustrates the dependence of the observed spectrum on the interaction gas.Comment: 11 pages, 2 figure
Spin-based quantum information processing with semiconductor quantum dots and cavity QED
A quantum information processing scheme is proposed with semiconductor
quantum dots located in a high-Q single mode QED cavity. The spin degrees of
freedom of one excess conduction electron of the quantum dots are employed as
qubits. Excitonic states, which can be produced ultrafastly with optical
operation, are used as auxiliary states in the realization of quantum gates. We
show how properly tailored ultrafast laser pulses and Pauli-blocking effects,
can be used to achieve a universal encoded quantum computing.Comment: RevTex, 2 figure
Universal Quantum Computation using Exchange Interactions and Teleportation of Single-Qubit Operations
We show how to construct a universal set of quantum logic gates using control
over exchange interactions and single- and two-spin measurements only.
Single-spin unitary operations are teleported instead of being executed
directly, thus eliminating a major difficulty in the construction of several of
the most promising proposals for solid-state quantum computation, such as
spin-coupled quantum dots, donor-atom nuclear spins in silicon, and electrons
on helium. Contrary to previous proposals dealing with this difficulty, our
scheme requires no encoding redundancy. We also discuss an application to
superconducting phase qubits.Comment: 4.5 pages, including 2 figure
A 750 mW, continuous-wave, solid-state laser source at 313 nm for cooling and manipulating trapped 9Be+ ions
We present a solid-state laser system that generates 750 mW of
continuous-wave single-frequency output at 313 nm. Sum-frequency generation
with fiber lasers at 1550 nm and 1051 nm produces up to 2 W at 626 nm. This
visible light is then converted to UV by cavity-enhanced second-harmonic
generation. The laser output can be tuned over a 495 GHz range, which includes
the 9Be+ laser cooling and repumping transitions. This is the first report of a
narrow-linewidth laser system with sufficient power to perform fault-tolerant
quantum-gate operations with trapped 9Be+ ions by use of stimulated Raman
transitions.Comment: 9 pages, 4 figure
A student teamwork induction protocol
Faulty group processes have harmful effects on performance but there is little research about intervention protocols to pre-empt them in HE. This naturalistic experiment compared a control cohort with an inducted cohort. The inducted cohort attended a workshop, consultations, elected a leader and used tools (a group log and group contract) designed to minimize social loafing, optimize coordination (by boosting good information sampling) and orient group dynamics towards the task. In the absence of inductions, a faulty system of processes was in play and this had a significant impact on group performance. In contrast, the inductions created a buffer. Structural equation modeling showed that the intervention made both group cohesion and conflict beneficial to group performance. The induction protocols enhanced students’ individual accountability, a sense of unique responsibility and dissent during group decision-making (which improved its quality). The implication is that inductions help optimize the processes within student teamwork
Testing Holographic Principle from Logarithmic and Higher Order Corrections to Black Hole Entropy
The holographic principle is tested by examining the logarithmic and higher
order corrections to the Bekenstein-Hawking entropy of black holes. For the BTZ
black hole, I find some disagreement in the principle for a holography screen
at spatial infinity beyond the leading order, but a holography with the screen
at the horizon does not, with an appropriate choice of a period parameter,
which has been undetermined at the leading order, in Carlip's horizon-CFT
approach for black hole entropy in any dimension. Its higher dimensional
generalization is considered to see a universality of the parameter choice. The
horizon holography from Carlip's is compared with several other realizations of
a horizon holography, including induced Wess-Zumino-Witten model approaches and
quantum geometry approach, but none of the these agrees with Carlip's, after
clarifications of some confusions. Some challenging open questions are listed
finally.Comment: To appear in JHEP. The corrections in Sec.2 with those that follow
are more clearly explained. Careful distingtion between the implications of
my results to AdS/CFT and to the holograhic principl
Influence of L-carnitine on litter characteristics from gilts harvested at day 40, 55, and 70 of gestation
Swine research, 2005 is known as Swine day, 2005A total of 59 gilts were used to determine the effects of supplemental L-carnitine on reproductive performance. Experimental treatments were arranged in a 2 × 3 factorial with main effects of L-carnitine (0 or 50 ppm) and day of gestation (40, 55, or 70). All gilts received a constant feed allowance of 3.86 lb/day and a top-dress containing either 0 or 88 mg of L-carnitine, starting on the first day of breeding and continuing until the day of harvest. Total litter size, total litter weight, and crown-to-rump length of fetuses were not different (P>0.10) between treatments at any gestation length. By d 70 of gestation, average fetus weight was heavier (P = 0.06) for fetuses from gilts fed L-carnitine, compared with fetuses from gilts fed the control diet. In
addition, at d 70, fetal insulin-like growth factor- II (IGF-II) concentrations were lower (P = 0.09) for fetuses from gilts fed L-carnitine than for fetuses from gilts fed the control diet. Feeding L-carnitine may have decreased fetal IGF-II, therefore increasing cell proliferation and delaying cell differentiation. These results show that providing supplemental Lcarnitine to gestating gilts has beneficial effects on average fetal weight, possibly observed because of its ability to reduce fetal IGF-II concentrations
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