Interpreting iron studies

No abstract available

Truthful Multi-unit Procurements with Budgets

We study procurement games where each seller supplies multiple units of his item, with a cost per unit known only to him. The buyer can purchase any number of units from each seller, values different combinations of the items differently, and has a budget for his total payment. For a special class of procurement games, the {\em bounded knapsack} problem, we show that no universally truthful budget-feasible mechanism can approximate the optimal value of the buyer within $\ln n$, where $n$ is the total number of units of all items available. We then construct a polynomial-time mechanism that gives a $4(1+\ln n)$-approximation for procurement games with {\em concave additive valuations}, which include bounded knapsack as a special case. Our mechanism is thus optimal up to a constant factor. Moreover, for the bounded knapsack problem, given the well-known FPTAS, our results imply there is a provable gap between the optimization domain and the mechanism design domain. Finally, for procurement games with {\em sub-additive valuations}, we construct a universally truthful budget-feasible mechanism that gives an $O(\frac{\log^2 n}{\log \log n})$-approximation in polynomial time with a demand oracle.Comment: To appear at WINE 201

Regression correction equation to adjust serum iron and ferritin concentrations based on C-reactive protein and albumin in patients receiving primary and secondary care

Background: Systemic inflammation, even at low levels, can greatly interfere with measures of iron status, making diagnosis of iron deficiency difficult. The objective of the present study was to create linear regression correction equations to adjust serum ferritin and iron concentrations based on measurements of the acute-phase proteins C-reactive protein (CRP) and albumin. Methods: Data from a cohort (1) of patients (n = 7226) in primary and secondary care who had serum ferritin, iron, CRP, and albumin measured at the same time point were examined. Linear regression coefficients were calculated for CRP and albumin with serum iron and ferritin as the outcome variables. Patients with ferritin <15 µg/L or serum iron <10 µmol/L were categorized as iron deficient. The equation was then applied to a cohort (2) of patients with colorectal cancer who had ferritin and iron measured preoperatively ( n = 356). Results: In cohort 1 there was a significant difference in the proportions of patients with serum ferritin <15 µg/L and serum iron <10 µmol/L, respectively, when the unadjusted (7% and 55%), adjusted based on CRP alone (13% and 26%), adjusted based on albumin alone (11% and 37%), and adjusted based on both CRP and albumin (24% and 15%) values were compared (both P < 0.001). In cohort 2 there was a significant difference in the proportions of patients with serum ferritin <15 µg/L and serum iron <10 µmol/L, respectively, when the unadjusted (28% and 66%), adjusted based on CRP alone (39% and 57%), adjusted based on albumin alone (39% and 59%), and adjusted based on both CRP and albumin (46% and 44%) values were compared (P < 0.001 and P < 0.004). Conclusions: In both cohorts the greatest increase in the proportion of patients meeting definitions of iron deficiency was found when adjustment was made for both CRP and albumin together. Even low levels of inflammation had a significant effect on serum iron and ferritin values

Testing the Mutually Enhanced Magicity Effect in Nuclear Incompressibility via the Giant Monopole Resonance in the 204,206,208^{204,206,208}Pb Isotopes

Using inelastic $\alpha$-scattering at extremely forward angles, including $0^\circ$, the strength distributions of the isoscalar giant monopole resonance (ISGMR) have been measured in the $^{204,206,208}$Pb isotopes in order to examine the proposed mutually enhanced magicity (MEM) effect on the nuclear incompressibility. The MEM effect had been suggested as a likely explanation of the "softness" of nuclear incompressibility observed in the ISGMR measurements in the Sn and Cd isotopes. Our experimental results rule out any manifestation of the MEM effect in nuclear incompressibility and leave the question of the softness of the open-shell nuclei unresolved still.Comment: Accepted for publication in Physics Letters B. Very minor changes in tex

TEX: The New Insensitive High Explosive

Insensitive high explosive 4, 10-dinitro-2,6,8, 12-tetraoxa-4, 10-diazatetracyclo (5.5.0.0.5,9 03,11) dodecane (TEX) has been synthesised by an improved laboratory-scale process using 93 per cent to 96 per cent nitric acid as nitrating agent. Characterisation of the product was done based on its physical constants, infrared, differential thermal analysis, and mass spectral studies. Explosive and ballistic parameters of TEX containing formulations were computed using Becker-Kistiakowsky-Wilson (BKW) code and NASA Chemical Equilibrium Composition- 71 programme, respectively. Semi-empirical quantum mechanical calculations using the parametric model 3 (PM3) method have been carried out for the TEX molecule. The optimised geometrical parameters and heats of formation were obtained from semi-empirical PM3

Probing astrophysically important states in the ²⁶Mg nucleus to study neutron sources for the s process

Background: The ²²Ne(α,n) ²⁵Mg reaction is the dominant neutron source for the slow neutron capture process (s process) in massive stars, and contributes, together with C¹³(α,n)O¹⁶, to the production of neutrons for the s process in asymptotic giant branch (AGB) stars. However, the reaction is endothermic and competes directly with ²²Ne(α,γ)²⁶Mg radiative capture. The uncertainties for both reactions are large owing to the uncertainty in the level structure of ²⁶Mg near the α and neutron separation energies. These uncertainties affect the s-process nucleosynthesis calculations in theoretical stellar models. Purpose: Indirect studies in the past have been successful in determining the energies and the γ-ray and neutron widths of the Mg26 states in the energy region of interest. But, the high Coulomb barrier hinders a direct measurement of the resonance strengths, which are determined by the α widths for these states. The goal of the present experiments is to identify the critical resonance states and to precisely measure the α widths by α-transfer techniques. Methods: The α-inelastic scattering and α-transfer measurements were performed on a solid ²⁶Mg target and a ²²Ne gas target, respectively, using the Grand Raiden Spectrometer at the Research Center for Nuclear Physics in Osaka, Japan. The (α,α′) measurements were performed at 0.45°, 4.1°, 8.6°, and 11.1° and the (⁶Li,d) measurements at 0° and 10°. The scattered α particles and deuterons were detected by the focal plane detection system consisting of multiwire drift chambers and plastic scintillators. The focal plane energy calibration allowed the study of ²⁶Mg levels from Eₓ = 7.69–12.06 MeV in the (α,α′) measurement and Eₓ = 7.36–11.32 MeV in the (⁶Li,d) measurement. Results: Six levels (Eₓ = 10717, 10822, 10951, 11085, 11167, and 11317 keV) were observed above the α threshold in the region of interest (10.61–11.32 MeV). The α widths were calculated for these states from the experimental data. The results were used to determine the α-capture induced reaction rates. Conclusion: The energy range above the α threshold in ²⁶Mg was investigated using a high resolution spectrometer. A number of states were observed for the first time in α-scattering and α-transfer reactions. The excitation energies and spin-parities were determined. Good agreement is observed for previously known levels in ²⁶Mg. From the observed resonance levels the Eₓ = 10717 keV state has a negligible contribution to the α-induced reaction rates. The rates are dominated in both reaction channels by the resonance contributions of the states at Ex = 10951, 11167, and 11317 keV. The Eₓ = 11167 keV state has the most appreciable impact on the (α,γ) rate and therefore plays an important role in the prediction of the neutron production in s-process environments

Vertex Sparsifiers: New Results from Old Techniques

Given a capacitated graph $G = (V,E)$ and a set of terminals $K \subseteq V$, how should we produce a graph $H$ only on the terminals $K$ so that every (multicommodity) flow between the terminals in $G$ could be supported in $H$ with low congestion, and vice versa? (Such a graph $H$ is called a flow-sparsifier for $G$.) What if we want $H$ to be a "simple" graph? What if we allow $H$ to be a convex combination of simple graphs? Improving on results of Moitra [FOCS 2009] and Leighton and Moitra [STOC 2010], we give efficient algorithms for constructing: (a) a flow-sparsifier $H$ that maintains congestion up to a factor of $O(\log k/\log \log k)$, where $k = |K|$, (b) a convex combination of trees over the terminals $K$ that maintains congestion up to a factor of $O(\log k)$, and (c) for a planar graph $G$, a convex combination of planar graphs that maintains congestion up to a constant factor. This requires us to give a new algorithm for the 0-extension problem, the first one in which the preimages of each terminal are connected in $G$. Moreover, this result extends to minor-closed families of graphs. Our improved bounds immediately imply improved approximation guarantees for several terminal-based cut and ordering problems.Comment: An extended abstract appears in the 13th International Workshop on Approximation Algorithms for Combinatorial Optimization Problems (APPROX), 2010. Final version to appear in SIAM J. Computin

The Traveling Salesman Problem: Low-Dimensionality Implies a Polynomial Time Approximation Scheme

The Traveling Salesman Problem (TSP) is among the most famous NP-hard optimization problems. We design for this problem a randomized polynomial-time algorithm that computes a (1+eps)-approximation to the optimal tour, for any fixed eps>0, in TSP instances that form an arbitrary metric space with bounded intrinsic dimension. The celebrated results of Arora (A-98) and Mitchell (M-99) prove that the above result holds in the special case of TSP in a fixed-dimensional Euclidean space. Thus, our algorithm demonstrates that the algorithmic tractability of metric TSP depends on the dimensionality of the space and not on its specific geometry. This result resolves a problem that has been open since the quasi-polynomial time algorithm of Talwar (T-04)

Measurement of the 58Ni(α, γ) 62Zn reaction and its astrophysical impact

Funding Details: PHY 08-22648, NSF, National Science Foundation; PHY 0969058, NSF, National Science Foundation; PHY 1102511, NSF, National Science FoundationCross section measurements of the 58Ni(α,γ)62Zn reaction were performed in the energy range Eα=5.5to9.5 MeV at the Nuclear Science Laboratory of the University of Notre Dame, using the NSCL Summing NaI(Tl) detector and the γ-summing technique. The measurements are compared to predictions in the statistical Hauser-Feshbach model of nuclear reactions using the SMARAGD code. It is found that the energy dependence of the cross section is reproduced well but the absolute value is overestimated by the prediction. This can be remedied by rescaling the α width by a factor of 0.45. Stellar reactivities were calculated with the rescaled α width and their impact on nucleosynthesis in type Ia supernovae has been studied. It is found that the resulting abundances change by up to 5% when using the new reactivities. © 2014 American Physical Society.Peer reviewe

Gaggle on the Gavel: Designing an Interactive Website to Create a Community of Lawyers

Law is behind other industries and professions in its implementation of technolo-gy that could make the practice of law and the delivery of legal services more ef-fective and satisfying. Although there has been considerable development in le-gal technology over the past few years, research identified the need for an interac-tive LinkedIn-style online community for lawyers to communicate other lawyers. Such a community would be particularly beneficial for solo practitioners, lawyers in small firms and lawyers in rural communities and would also provide a con-venient way to connect with lawyers for referrals and recommendations, for spe-cialized expertise and to develop contacts in different geographic locations. Ten-tatively titled Gaggle on the Gavel is an attempt to create such a community that would gather a number of attractive features and functionality under one umbrella and be compliant with the rules of professional conduct with respect to client con-fidentiality, security, advertising and solicitation. A system has been designed, prototyped and revised based on feedback from a focus group of lawyers