Open Charm and Beauty at Ultrarelativistic Heavy Ion Colliders

Important goals of RHIC and LHC experiments with ion beams include the creation and study of new forms of matter, such as the Quark Gluon Plasma. Heavy quark production and attenuation will provide unique tomographic probes of that matter. We predict the suppression pattern of open charm and beauty in $Au+Au$ collisions at RHIC and LHC energies based on the DGLV formalism of radiative energy loss. A cancelation between effects due to the $\sqrt{s}$ energy dependence of the high $p_T$ slope and heavy quark energy loss is predicted to lead to surprising similarity of heavy quark suppression at RHIC and LHC.Comment: 4 pages, 6 *.eps files combined into 4 figure

Dirac Quantization Condition for Monopole in Noncommutative Space-Time

Since the structure of space-time at very short distances is believed to get modified possibly due to noncommutativity effects and as the Dirac Quantization Condition (DQC), $\mu e = \frac{N}{2}\hbar c$, probes the magnetic field point singularity, a natural question arises whether the same condition will still survive. We show that the DQC on a noncommutative space in a model of dynamical noncommutative quantum mechanics remains the same as in the commutative case to first order in the noncommutativity parameter $\theta$, leading to the conjecture that the condition will not alter in higher orders.Comment: 11 page

LQG for Constrained Linear Systems: Indirect Feedback Stochastic MPC with Kalman Filtering

We present an output feedback stochastic model predictive control (SMPC) approach for linear systems subject to Gaussian disturbances and measurement noise and probabilistic constraints on system states and inputs. The presented approach combines a linear Kalman filter for state estimation with an indirect feedback SMPC, which is initialized with a predicted nominal state, while feedback of the current state estimate enters through the objective of the SMPC problem. For this combination, we establish recursive feasibility of the SMPC problem due to the chosen initialization, and closed-loop chance constraint satisfaction thanks to an appropriate tightening of the constraints in the SMPC problem also considering the state estimation uncertainty. Additionally, we show that for specific design choices in the SMPC problem, the unconstrained linear-quadratic-Gaussian (LQG) solution is recovered if it is feasible for a given initial condition and the considered constraints. We demonstrate this fact for a numerical example, and show that the resulting output feedback controller can provide non-conservative constraint satisfaction.Comment: 7 pages, 1 figur

An Evidential Reasoning Approach to Sarbanes-Oxley Mandated Internal Control Risk Assessment

This is the peer reviewed version of the following article: Mock, T., L. Sun, R. P. Srivastava, and M. Vasarhelyi. " An Evidential Reasoning Approach to Sarbanes-Oxley Mandated Internal Control Risk Assessment under Dempster-Shafer Theory", 2009, ABACUS, Vol. 45, No. 1, pp. 66-87. , which has been published in final form at http://doi.org/10.1016/j.accinf.2008.10.003. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.In response to the enactment of the Sarbanes-Oxley Act 2002 and of the release of the Public Company Accounting Oversight Board (PCAOB) Auditing Standard No. 5, this study develops a risk-based evidential reasoning approach for assessing the effectiveness of internal controls over financial reporting (ICoFR). This approach provides a structured methodology for assessing the effectiveness of ICoFR by considering relevant factors and their interrelationships. The Dempster-Shafer theory of belief functions is utilized for representing risk. First, we develop a generic ICoFR assessment model based upon a Big 4 audit firm’s approach and apply it to a real-world example. Then, based on this model, we develop a quantitative representation of various levels of ICoFR effectiveness and related risk-assessment as defined by the PCAOB and contrast these representations with levels implied by Auditing Standard No. 5. In doing so, we demonstrate the potential value of formal risk assessment models in both facilitating the assessment of risks in an individual engagement and in assessing the effects of different regulations

Jet Quenching in Non-Conformal Holography

We use our non-conformal holographic bottom-up model for QCD described in 1012.0116 to further study the effect of the QCD trace anomaly on the energy loss of both light and heavy quarks in a strongly coupled plasma. We compute the nuclear modification factor $R_{AA}$ for bottom and charm quarks in an expanding plasma with Glauber initial conditions. We find that the maximum stopping distance of light quarks in a non-conformal plasma scales with the energy with a temperature (and energy) dependent effective power.Comment: 4 pages, 1 figure. Proceedings for Quark Matter 201

Virtual Auditing Agents: The EDGAR Agent Challenge

Intelligent agents can be used as agents of organizational change. This potential exists in the domain of accounting audit, where much of what is currently done manually in batch mode could be done continuously and on-line. We discuss the use of intelligent Internet agents as a way of changing and expanding audit practices in the virtual world. A quality/service framework is presented that suggests ways that accounting firms can evolve in this era of on-line opportunities. The EDGAR Agent is presented as an example of an intelligent Internet agent that gathers financial information. The challenges involved in the development of the EDGAR agent are analyzed, providing insight into the practical aspects of agent technology designed for a specific business domain. A test of the agent is presented, with comments and suggestions from financial practitioners that will be integrated into the research stream

Recipient‐related predictors of kidney transplantation outcomes in the elderly

Background It is not clear whether in old people with end‐stage renal disease kidney transplantation is superior to dialysis therapy. Methods We compared mortality rates between kidney transplant recipients ( KTR s) and the general population across different age categories. We also examined patient and allograft survival in 15 667 elderly KTR s (65–30 kg/m 2 ) was associated with 19% higher risk of graft failure ( HR : 1.19 [1.07–1.33], p = 0.002). Diabetes was a predictor of worse patient survival in all age groups but poorer allograft outcome in the youngest age group (65–<70 yr old) only. None of the examined risk factors affected allograft outcome in the oldest group (≥75 yr old) although there was a 49% lower trend of graft failure in very old Hispanic recipients ( HR : 0.51 [0.26–1.01], p = 0.05). Conclusions Kidney transplantation may attenuate the age‐associated increase in mortality, and its superior survival gain is most prominent in the oldest recipients (≥75 yr old). The potential protective effect of kidney transplantation on longevity in the elderly deserves further investigation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98362/1/ctr12106.pd

The White-Box Adversarial Data Stream Model

We study streaming algorithms in the white-box adversarial model, where the stream is chosen adaptively by an adversary who observes the entire internal state of the algorithm at each time step. We show that nontrivial algorithms are still possible. We first give a randomized algorithm for the $L_1$-heavy hitters problem that outperforms the optimal deterministic Misra-Gries algorithm on long streams. If the white-box adversary is computationally bounded, we use cryptographic techniques to reduce the memory of our $L_1$-heavy hitters algorithm even further and to design a number of additional algorithms for graph, string, and linear algebra problems. The existence of such algorithms is surprising, as the streaming algorithm does not even have a secret key in this model, i.e., its state is entirely known to the adversary. One algorithm we design is for estimating the number of distinct elements in a stream with insertions and deletions achieving a multiplicative approximation and sublinear space; such an algorithm is impossible for deterministic algorithms. We also give a general technique that translates any two-player deterministic communication lower bound to a lower bound for {\it randomized} algorithms robust to a white-box adversary. In particular, our results show that for all $p\ge 0$, there exists a constant $C_p>1$ such that any $C_p$-approximation algorithm for $F_p$ moment estimation in insertion-only streams with a white-box adversary requires $\Omega(n)$ space for a universe of size $n$. Similarly, there is a constant $C>1$ such that any $C$-approximation algorithm in an insertion-only stream for matrix rank requires $\Omega(n)$ space with a white-box adversary. Our algorithmic results based on cryptography thus show a separation between computationally bounded and unbounded adversaries. (Abstract shortened to meet arXiv limits.)Comment: PODS 202

Glycemic Control and Cardiovascular Mortality in Hemodialysis Patients With Diabetes

Previous observational studies using differing methodologies have yielded inconsistent results regarding the association between glycemic control and outcomes in diabetic patients receiving maintenance hemodialysis (MHD). We examined mortality predictability of A1C and random serum glucose over time in a contemporary cohort of 54,757 diabetic MHD patients (age 63 ± 13 years, 51% men, 30% African Americans, 19% Hispanics). Adjusted all-cause death hazard ratio (HR) for baseline A1C increments of 8.0–8.9, 9.0–9.9, and ≥10%, compared with 7.0–7.9% (reference), was 1.06 (95% CI 1.01–1.12), 1.05 (0.99–1.12), and 1.19 (1.12–1.28), respectively, and for time-averaged A1C was 1.11 (1.05–1.16), 1.36 (1.27–1.45), and 1.59 (1.46–1.72). A symmetric increase in mortality also occurred with time-averaged A1C levels in the low range (6.0–6.9%, HR 1.05 [95% CI 1.01–1.08]; 5.0–5.9%, 1.08 [1.04–1.11], and ≤5%, 1.35 [1.29–1.42]) compared with 7.0–7.9% in fully adjusted models. Adjusted all-cause death HR for time-averaged blood glucose 175–199, 200–249, 250–299, and ≥300 mg/dL, compared with 150–175 mg/dL (reference), was 1.03 (95% CI 0.99–1.07), 1.14 (1.10–1.19), 1.30 (1.23–1.37), and 1.66 (1.56–1.76), respectively. Hence, poor glycemic control (A1C ≥8% or serum glucose ≥200 mg/dL) appears to be associated with high all-cause and cardiovascular death in MHD patients. Very low glycemic levels are also associated with high mortality risk