Evaluating the Holevo Cramér-Rao bound for multiparameter quantum metrology

Only with the simultaneous estimation of multiple parameters are the quantum aspects of metrology fully revealed. This is due to the incompatibility of observables. The fundamental bound for multiparameter quantum estimation is the Holevo Cram´er-Rao bound (HCRB) whose evaluation has so far remained elusive. For finite-dimensional systems we recast its evaluation as a semidefinite program, with reduced size for rank-deficient states. We show that it also satisfies strong duality. We use this result to study phase and loss estimation in optical interferometry and three-dimensional magnetometry with noisy multiqubit systems. For the former, we show that, in some regimes, it is possible to attain the HCRB with the optimal (single-copy) measurement for phase estimation. For the latter, we show a nontrivial interplay between the HCRB and incompatibility and provide numerical evidence that projective single-copy measurements attain the HCRB in the noiseless 2-qubit case

Local School Wellness Policies: How Are Schools Implementing the Congressional Mandate?

Summarizes research on school policies to reduce childhood obesity, with a focus on their quality, evaluation, and funding; nutritional standards and nutrition education requirements; and physical education requirements. Identifies remaining challenges

Why medical students choose not to carry out an intercalated BSc : a questionnaire study.

Peer reviewedPublisher PD

Marijuana Decriminalization: What does it mean in the United States?

It is well known in the drug policy field that eleven states reduced the criminal sanctions associated with possession of small amounts of marijuana. In this paper we review the eleven original decriminalization statutes, documenting key dimensions of these laws and identifying their common denominator. We then examine state laws in effect as of December 31, 1999, along the same key dimensions and show that it is impossible to uniquely identify the so-called decriminalized states. We show the extent to which non-decriminalized states have also reduced penalties associated with possession of small amounts of marijuana as early as 1989, calling into question the interpretation of studies evaluating this policy during the past decade. We conclude by showing that the inclusion of legal dimensions of the policy does not diminish the association identified between decriminalization and recent use, raising questions about how researchers should interpret such findings.

An Introduction to Hearing Loss: Examining Conductive & Sensorineural Loss

A presentation on hearing loss made at the 2017 Charter Oak Conference held in Groton, CT

The Nature of Working Memory in Aphasia

Thesis (PhD) - Indiana University, Speech and Hearing, 2007It is well known that many adults with aphasia demonstrate concomitant deficits in higher-level cognitive functions, including attention, executive function, and short-term and working memory. This has led to two premises: (a) the domain-specific hypothesis, in which aphasia is associated with additional cognitive deficits only to the extent that these are dependent upon language; and (b) the domain-general hypothesis, in which aphasia is associated with nonlinguistic cognitive impairments as a consequence of either overlapping anatomy or widespread cortical changes post-insult. The purpose of this research was to disentangle these competing hypotheses with regards to working memory (WM) in adults with aphasia. Like other categories of cognitive impairment in this patient group, past research has identified but failed to elucidate WM impairments in aphasic language processing. Toward this end, 15 adults with left-hemisphere damage and aphasia (LHD) and 12 non-brain-damaged controls (NBD) completed a parametric WM task with systematic variation of psycholinguistic complexity (high-frequency, low-frequency, or non-nameable stimuli) and WM load (0-, 1-, and 2-back). Data were analyzed with respect to the differential impact of these variables within and across subjects and groups. Whereas expected effects of word frequency were elicited in stimulus confrontation naming, LHD subjects were affected only minimally by frequency manipulations during the n-back task. Instead, these subjects demonstrated a significant performance decrement relative to controls with increasing WM load. Moreover, aphasia severity was moderately correlated with WM for non-nameable (i.e., more difficult) but not nameable stimuli. At the theoretical level, these results support a resource-based processing model in aphasia; at the neurobiological level, these findings are consistent with the proposition of widespread cortical connectivity changes irrespective of type or location of brain damage. A secondary purpose of this study was to investigate the reliability of LHD performance on the n-back task, given the known performance variability associated with aphasia and the general dearth of reliability data for higher-level tasks. Results demonstrated that the n-back task is a reliable WM indicator over time for this population