Electrical and optical properties of fluid iron from compressed to expanded regime

Using quantum molecular dynamics simulations, we show that the electrical and optical properties of fluid iron change drastically from compressed to expanded regime. The simulation results reproduce the main trends of the electrical resistivity along isochores and are found to be in good agreement with experimental data. The transition of expanded fluid iron into a nonmetallic state takes place close to the density at which the constant volume derivative of the electrical resistivity on internal energy becomes negative. The study of the optical conductivity, absorption coefficient, and Rosseland mean opacity shows that, quantum molecular dynamics combined with the Kubo-Greenwood formulation provides a powerful tool to calculate and benchmark the electrical and optical properties of iron from expanded fluid to warm dense region

Non-Markovian Quantum Gate Set Tomography

Engineering quantum devices requires reliable characterization of the quantum system including qubits, quantum operations (aka instruments) and the quantum noise. Recently, quantum gate set tomography (GST) has emerged as a promissing technique to self-consistently describe the quantum states, gates and measurements. However, non-Markovian correlations between the quantum system and environment cause the reliability regression of GST. It is essential to simultaneously describe the gate set and non-Markovian correlations. To this end, we first propose a self-consistent operational method, named instrument set tomography (IST), for non-Markovian GST. Based on the stochastic quantum process, the instrument set is defined to describe instruments, the initial state, and non-Markovian system-environment (SE) correlations. First, we propose a linear inversion IST (LIST) to detect and describe the disharmony of linear relationship of instruments and SE correlations with gauge freedom. However, LIST cannot always determine physical implementable instrument set because of the absence of constraints. Then, a physically constrained statistical method based on the miximum likelihood estimation for IST (MLE-IST) is proposed with polynomial number of parameters with respect to the Markovian order. It shows significant flexibility that suit for different types of device, e.g. noisy intermediate-scale quantum (NISQ) devices, by adjusting the model and constraints. The experimental results show the effectiveness of describing instruments and the non-Markovian quantum system. As a result, the IST provides an essential method for benchmarking and developing quantum devices in the aspect of instrument set

Staff Time and Motion Assessment for Administration of Erythropoiesis-Stimulating Agents: A Two-Phase Pilot Study in Clinical Oncology Practices

BACKGROUND: Erythropoiesis-stimulating agents (ESAs) are used for the management of anaemia in patients with non-myeloid malignancies where anaemia is due to the effect of concomitant myelosuppressive chemotherapy. Assessing the impact of different ESA dosing regimens on office staff time and projected labour costs is an important component of understanding the potential for optimization of oncology practice efficiencies. OBJECTIVES: A two-phase study was conducted to evaluate staff time and labour costs directly associated with ESA administration in real-world oncology practice settings among cancer patients undergoing chemotherapy. The objective of Phase 1 was to determine the mean staff time required for the process of ESA administration in patients with anaemia due to concomitantly administered chemotherapy. The objective of Phase 2 was to quantify and compare the mean staff time and mean labour costs of ESA administered once weekly (qw) with ESA once every 3 weeks (q3w) over an entire course of chemotherapy. METHODS: Phase 1 was a prospective, cross-sectional time and motion study conducted in six private oncology practices in the US based on nine steps associated with ESA administration. Using findings from Phase 1, Phase 2 was conducted as a retrospective chart review to collect data on the number and types of visits in two private oncology practices for patients receiving a complete course of myelosuppressive chemotherapy. RESULTS: In Phase 1, the mean total time that clinic staff spent on ESA administration was 23.2 min for patient visits that included chemotherapy administration (n(chemo) = 37) and 21.5 min when only ESA was administered (n(ESAonly) = 36). In Phase 2, the mean duration of treatment was significantly longer for q3w than qw (53.84 days for qw vs. 113.38 for q3w, p < 0.0001); thus, analyses were adjusted using analysis of covariance (ANCOVA) for episode duration for between-group comparisons. Following adjustment by ANCOVA, qw darbepoetin alfa (DA) patients (n(qw) = 83) required more staff time for ESA + chemotherapy visits and ESA-only visits than q3w patients (n(q3w) = 118) over a course of chemotherapy. Overall, mean total staff time expended per chemotherapy course was greater for patients receiving qw versus q3w DA. Weekly DA dosing was associated with greater projected mean labour costs ($US38.16 vs.$US31.20 [average for 2007–2010]). CONCLUSIONS: The results from this real-world study demonstrate that oncology practices can attain staff time and labour costs savings through the use of q3w ESA. The degree of savings depends on the individual oncology practice’s staffing model and ESA administration processes, including those that allow for optimized synchronization of patient visits for ESA and chemotherapy administration. These findings indicate that additional research using standard ESA administration protocols for longer periods of time with a larger number of oncology practices and patients should be conducted to confirm these findings

Transfusion burden in non-dialysis chronic kidney disease patients with persistent anemia treated in routine clinical practice: a retrospective observational study

Background: Transfusion patterns are not well characterized in non-dialysis (ND) chronic kidney disease (CKD) patients. This study describes the proportion of patients transfused, units of blood transfused and trigger-hemoglobin (Hb) levels for transfusions in severe anemic, ND-CKD patients in routine practice. Methods. A retrospective cohort study of electronic medical record data from the Henry Ford Health identified 374 adult, ND-CKD patients with severe anemia (Hb \u3c 10 g/dL and subsequent use of erythropoiesis-stimulating agents [ESA] therapy, blood transfusions, or a second Hb \u3c 10 g/dL) between January 2004 and June 2008. Exclusions included those with prior diagnoses of cancer, renal or liver transplant, end-stage renal disease, acute bleeding, trauma, sickle cell disease, or aplastic anemia. A gap of ≥1 days between units of blood transfused was counted as a separate transfusion. Results: At least 1 transfusion (mean of 2 units; range, 1-4) was administered to 20% (75/374) of ND-CKD patients with mean (±SD) follow-up of 459 (±427) days. The mean (±SD) Hb level closest and prior to a transfusion was 8.8 (±1.5) g/dL. Patients who were hospitalized in the 6 months prior to their first anemia diagnosis were 6.3 times more likely to receive a blood transfusion than patients who were not hospitalized (p \u3c 0.0001). Patients with peripheral vascular disease (PVD) were twice as likely to have a transfusion as patients without PVD (p = 0.04). Conclusions: Transfusions were prevalent and the trigger hemoglobin concentration was approximately 9 g/dL among ND-CKD patients with anemia. To reduce the transfusion burden, clinicians should consider other anemia treatments including ESA therapy. © 2012 Fox et al; licensee BioMed Central Ltd

Health and Acces Effects of New Drugs: Combining Experimental and Non-Experimental Data

We propose to combine clinical trial and estimates of behavioral responses in the population to quantify the value of new drug innovations when such values cannot be obtained by randomized experiments alone. New drugs are seen as having two distinct effects on patients. First, they can provide better outcomes for patients currently under treatment, due to better clinical efficacy. Second, they can also provide treatment access to more patients, perhaps by reducing side effects or expanding treatment. We compare these “clinical” and “access” effects using claims data, data on the arrival rate of new drugs, and the clinical trials literature on the effectiveness of these drugs. We find that the effect of new drug introductions on the number of patients treated accounts for a substantial majority of the value created by new drugs

NMR evidence of spinon localization in kagome antiferromagnet YCu3_3(OH)6_6Br2_2[Br1−x_{1-x}(OH)x_x]

We performed nuclear magnetic resonance studies on a kagome antiferromagnet YCu$_3$(OH)$_6$Br$_2$[Br$_{1-x}$(OH)$_{x}$]. No significant NMR spectral broadening is found in the Br center peak from 1 K down to 0.05 K, indicating absence of static antiferromagnetic ordering. In contrast to signatures of dominant 2D kagome antiferromagnetic fluctuations at temperature above 30 K, both the Knight shift $K_{\rm{n}}$ and the spin-lattice relaxation rate $1/T_{1}$ increase when the sample is cooled from 30 K to 8 K, which can be attributed to the scattering of spin excitations by strong non-magnetic impurities. Unusually, a hump is observed in $K_{\rm{n}}$ and $1/T_{2}$ close to 2 K (far below the exchange energy), which indicates the existence of excitations with a large density of states close to zero energy. These phenomena are reproduced by a mean-field simulation of Heisenberg model with bond-dependent exchange interactions, where the sign fluctuations in the spinon kinetic terms caused by impurities result in localization of spinons and an almost flat band close to the Fermi energy.Comment: 9 pages, 7 figures. The supplementary materials can be obtained upon reques