Leaf Processing in a Slough of an Ozark Stream

Processing of sugar maple (Acer saccharum), black oak (Quercus velutina), and American sycamore (Platanus occidentalis) was investigated in a slough of the Illinois River, Benton County, Arkansas, using 5-gram packs in wire baskets. Oak and sycamore showed similar degradation rates, while maple was processed much faster. All processing rates were strongly retarded during a period of siltation. Chironomid larvae were the dominant organisms associated with the packs and their numbers were depressed by the silt influx. Shredders were notably few in number as compared with studies from the northwestern United States

Measurement of collagen synthesis by cells grown under different mechanical stimuli

INTRODUCTION: The use of scaffolds in tissue engineering is essential to provide cells with a matrix for cell proliferation and differentiation resulting in tissue regeneration. Normally this process involves seeding cells onto an artificial biodegradable scaffold providing mechanical support for cells until there is sufficient extracellular matrix deposition (ECM) to replace the artificial scaffold. Collagen is the bulk protein found in the ECM and measurement of its synthesis is the most direct, absolute indicator of ECM production

Mortality and Malnutrition Among Populations Living in South Darfur, Sudan: Results of 3 Surveys, September 2004.

CONTEXT: Mass violence against civilians in the west of Sudan has resulted in the displacement of more than 1.5 million people (25% of the population of the Darfur region). Most of these people are camped in 142 settlements. There has been increasing international concern about the health status of the displaced population. OBJECTIVE: To perform rapid epidemiological assessments of mortality and nutritional status at 3 sites in South Darfur for relief efforts. DESIGN, SETTING, AND PARTICIPANTS: In August and September 2004, mortality surveys were conducted among 137,000 internally displaced persons (IDPs) in 3 sites in South Darfur (Kass [n = 900 households], Kalma [n = 893 households], and Muhajiria [n = 900 households]). A nutritional survey was performed concomitantly among children aged 6 to 59 months using weight for height as an index of acute malnutrition (Kass [n = 894], Kalma [n = 888], and Muhajiria [n = 896]). A questionnaire detailing access to food and basic services was administered to a subset of households (n = 210 in each site). MAIN OUTCOME MEASURES: Crude and under 5-year mortality rates and nutritional status of IDPs in Kass, Kalma, and Muhajiria, South Darfur. RESULTS: Crude mortality rates, expressed as deaths per 10,000 per day, were 3.2 (95% confidence interval [CI], 2.2-4.1) in Kass, 2.0 (95% CI, 1.3-2.7) in Kalma, and 2.3 (95% CI, 1.2-3.4) in Muhajiria. Under 5-year mortality rates were 5.9 (95% CI, 3.8-8.0) in Kass, 3.5 (95% CI, 1.5-5.7) in Kalma, and 1.0 (95% CI, 0.03-1.9) in Muhajiria. During the period of displacement covered by our survey in Muhajiria, violence was reported to be responsible for 72% of deaths, mainly among young men. Diarrheal disease was reported to cause between 25% and 47% of deaths in camp residents and mainly affected the youngest and oldest age groups. Acute malnutrition was common, affecting 14.1% of the target population in Kass, 23.6% in Kalma, and 10.7% in Muhajiria. CONCLUSION: This study provides epidemiological evidence of the high rates of mortality and malnutrition among the displaced population in South Darfur and reinforces the need to mount appropriate and timely humanitarian responses

Quantum atom optics with fermions from molecular dissociation

We study a fermionic atom optics counterpart of parametric down-conversion with photons. This can be realized through dissociation of a Bose-Einstein condensate of molecular dimers consisting of fermionic atoms. We present a theoretical model describing the quantum dynamics of dissociation and find analytic solutions for mode occupancies and atomic pair correlations, valid in the short time limit. The solutions are used to identify upper bounds for the correlation functions, which are applicable to any fermionic system and correspond to ideal particle number-difference squeezingComment: Changes in response to referees' comments, updated reference

Limits on new long range nuclear spin-dependent forces set with a K-3He co-magnetometer

A magnetometer using spin-polarized K and $^3$He atoms occupying the same volume is used to search for anomalous nuclear spin-dependent forces generated by a separate $^3$He spin source. We measure changes in the $^3$He spin precession frequency with a resolution of 18 pHz and constrain anomalous spin forces between neutrons to be less than $2 \times 10^{-8}$ of their magnetic or less than $2\times 10^{-3}$ of their gravitational interactions on a length scale of 50 cm. We present new limits on neutron coupling to light pseudoscalar and vector particles, including torsion, and constraints on recently proposed models involving unparticles and spontaneous breaking of Lorentz symmetry.Comment: 4 pages, 4 figures, latest version as appeared in PR

Uniform Penalty inversion of two-dimensional NMR Relaxation data

The inversion of two-dimensional NMR data is an ill-posed problem related to the numerical computation of the inverse Laplace transform. In this paper we present the 2DUPEN algorithm that extends the Uniform Penalty (UPEN) algorithm [Borgia, Brown, Fantazzini, {\em Journal of Magnetic Resonance}, 1998] to two-dimensional data. The UPEN algorithm, defined for the inversion of one-dimensional NMR relaxation data, uses Tikhonov-like regularization and optionally non-negativity constraints in order to implement locally adapted regularization. In this paper, we analyze the regularization properties of this approach. Moreover, we extend the one-dimensional UPEN algorithm to the two-dimensional case and present an efficient implementation based on the Newton Projection method. Without any a-priori information on the noise norm, 2DUPEN automatically computes the locally adapted regularization parameters and the distribution of the unknown NMR parameters by using variable smoothing. Results of numerical experiments on simulated and real data are presented in order to illustrate the potential of the proposed method in reconstructing peaks and flat regions with the same accuracy

Gravitational Constraint Combinations Generate a Lie Algebra

We find a first--order partial differential equation whose solutions are all ultralocal scalar combinations of gravitational constraints with Abelian Poisson brackets between themselves. This is a generalisation of the Kucha\v{r} idea of finding alternative constraints for canonical gravity. The new scalars may be used in place of the hamiltonian constraint of general relativity and, together with the usual momentum constraints, replace the Dirac algebra for pure gravity with a true Lie algebra: the semidirect product of the Abelian algebra of the new constraint combinations with the algebra of spatial diffeomorphisms.Comment: 10 pages, latex, submitted to Classical and Quantum Gravity. Section 3 is expanded and an additional solution provided, minor errors correcte

Adapting Real Quantifier Elimination Methods for Conflict Set Computation

The satisfiability problem in real closed fields is decidable. In the context of satisfiability modulo theories, the problem restricted to conjunctive sets of literals, that is, sets of polynomial constraints, is of particular importance. One of the central problems is the computation of good explanations of the unsatisfiability of such sets, i.e.\ obtaining a small subset of the input constraints whose conjunction is already unsatisfiable. We adapt two commonly used real quantifier elimination methods, cylindrical algebraic decomposition and virtual substitution, to provide such conflict sets and demonstrate the performance of our method in practice

Rethinking the Properties of the Quark-Gluon Plasma at T∼TcT\sim T_c

We argue that although at asymptotically high temperatures the QGP in bulk behaves as a gas of weakly interacting quasiparticles (modulo long-range magnetism), at temperatures up to few times the critical temperature $T_c$ it displays different properties. If the running of the QCD coupling constant continues in the Coulomb phase till the screening length scale, it reaches the strong coupling treshold $\alpha_s(m_D)\sim 1$. As a result, the Coulomb phase supports weakly bound Coulombic s-wave $\bar c c$, light quark and even $gg$ states. The existence of shallow bound states dramatically increases the quasiparticle rescattering at low energies, reducing the viscosity and thereby explaining why heavy ion collisions at RHIC exhibit robust collective phenomena. In conformal gauge theories at finite temperature the Coulomb binding persists further in the strong coupling regime, as found for ${\cal N}=4$ SUSY YM in the Maldacena regime.Comment: v2 version have one more figure and one more reference, v3 is the same as v2 except a double-page format (the v2 had corrupted last lines on the page