133 research outputs found
On the Observables Describing a Quantum Reference Frame
A reference frame F is described by the element g of the Poincare' group P
which connects F with a given fixed frame F_0. If F is a quantum frame, defined
by a physical object following the laws of quantum physics, the parameters of g
have to be considered as quantum observables. However, these observables are
not compatible and some of them, namely the coordinates of the origin of F,
cannot be represented by self-adjoint operators. Both these difficulties can be
overcome by considering a positive-operator-valued measure (POVM) on P,
covariant with respect to the left translations of the group, namely a
covariance system. We develop a construction procedure for this kind of
mathematical structure. The formalism is also used to discuss the quantum
observables measured with respect to a quantum reference frame.Comment: 23 pages, no figure
Evaluating and Monitoring Energy Conservation in Multibuilding Clusters with Statistical Models
A standardized method for modeling
energy consumption in mixed
clusters of residential and commercial
buildings is described. The
basic approach is to delineate energy
consumption along three dimensions:
time, day-length, and temperature.
The temperature-sensitive
portion of energy consumption is
captured by the Princeton Scorekeeping
Method (PRISM). The time- and
daylength-sensitive portions of
energy consumption are captured by
other variables. The models were
designed to aid in determining the
scope and performance of alternative
financing activities on a U.S. Army
base
Energy Use Analysis for the Federal Energy Management Program
Recent congressional legislation allows federal agencies new authorities to
contract for energy savings by sharing the
acquired savings with an energy service
company. As part of its charter to make
the federal government more energy-efficient, the Federal Energy Management Program
(FEMP) endeavors to improve the technical basis for such performance-based
contracting. Specific tasks include the
development of improved energy use baselining methods, refinement of a simplified
energy analysis method and support to
users, preparation of guidelines and procedures
for energy savings initiatives,
and publication of a manual to guide identification and analysis of energy conservation measures. This paper describes the
current status and planned progress in
each of these areas, and how these relate
to several planned shared savings projects
Use of Metering for Facility and Whole Building Energy Analysis by the U.S. Depratment of Energy Federal Energy Management Program
This paper details how the U.S. Department of
Energy, Federal Energy Management Program (FEMP) is
applying metering technology to conduct empirically
based analyses o f energy use by federal agencies.
Continuing developments in sensors, data acquisition systems, microcomputers and monitoring protocols
are reducing the costs of metering to the point
that it is becoming "too cheap not to meter" energy
and the determinants of energy use at federal
facilities . This has widespread consequence for
FEMP if one accepts the axiom that "one can't manage
what one doesn't measure."
Several recently completed and ongoing
activities being managed by Pacific Northwest
laboratory for FEMP are highlighted in this
paper. This includes the metering of energy end uses
for a research laboratory building to support
a shared energy savings contract, analysis of
utility billing records, climate, and characteristics data for entire military bases to prioritize
energy use testing requirements, and enhancements
to simplified energy analysis tools to help federal
energy decision-makers identify and evaluate cost-effective energy savings opportunities
The Time-Energy Uncertainty Relation
The time energy uncertainty relation has been a controversial issue since the
advent of quantum theory, with respect to appropriate formalisation, validity
and possible meanings. A comprehensive account of the development of this
subject up to the 1980s is provided by a combination of the reviews of Jammer
(1974), Bauer and Mello (1978), and Busch (1990). More recent reviews are
concerned with different specific aspects of the subject. The purpose of this
chapter is to show that different types of time energy uncertainty relation can
indeed be deduced in specific contexts, but that there is no unique universal
relation that could stand on equal footing with the position-momentum
uncertainty relation. To this end, we will survey the various formulations of a
time energy uncertainty relation, with a brief assessment of their validity,
and along the way we will indicate some new developments that emerged since the
1990s.Comment: 33 pages, Latex. This expanded version (prepared for the 2nd edition
of "Time in quantum mechanics") contains minor corrections, new examples and
pointers to some additional relevant literatur
Events in a Non-Commutative Space-Time
We treat the events determined by a quantum physical state in a
noncommutative space-time, generalizing the analogous treatment in the usual
Minkowski space-time based on positive-operator-valued measures (POVMs). We
consider in detail the model proposed by Snyder in 1947 and calculate the POVMs
defined on the real line that describe the measurement of a single coordinate.
The approximate joint measurement of all the four space-time coordinates is
described in terms of a generalized Wigner function (GWF). We derive lower
bounds for the dispersion of the coordinate observables and discuss the
covariance of the model under the Poincare' group. The unusual transformation
law of the coordinates under space-time translations is interpreted as a
failure of the absolute character of the concept of space-time coincidence. The
model shows that a minimal length is compatible with Lorents covariance.Comment: 13 pages, revtex. Introductory part shortened and some arguments made
more clea
Development and Validation of Automated Magnetic Resonance Parkinsonism Index 2.0 to Distinguish Progressive Supranuclear Palsy-Parkinsonism From Parkinson's Disease
Background: Differentiating progressive supranuclear palsy-parkinsonism (PSP-P) from Parkinson's disease (PD) is clinically challenging. Objective: This study aimed to develop an automated Magnetic Resonance Parkinsonism Index 2.0 (MRPI 2.0) algorithm to distinguish PSP-P from PD and to validate its diagnostic performance in two large independent cohorts. Methods: We enrolled 676 participants: a training cohort (n = 346; 43 PSP-P, 194 PD, and 109 control subjects) from our center and an independent testing cohort (n = 330; 62 PSP-P, 171 PD, and 97 control subjects) from an international research group. We developed a new in-house algorithm for MRPI 2.0 calculation and assessed its performance in distinguishing PSP-P from PD and control subjects in both cohorts using receiver operating characteristic curves. Results: The automated MRPI 2.0 showed excellent performance in differentiating patients with PSP-P from patients with PD and control subjects both in the training cohort (area under the receiver operating characteristic curve [AUC] = 0.93 [95% confidence interval, 0.89–0.98] and AUC = 0.97 [0.93–1.00], respectively) and in the international testing cohort (PSP-P versus PD, AUC = 0.92 [0.87–0.97]; PSP-P versus controls, AUC = 0.94 [0.90–0.98]), suggesting the generalizability of the results. The automated MRPI 2.0 also accurately distinguished between PSP-P and PD in the early stage of the diseases (AUC = 0.91 [0.84–0.97]). A strong correlation (r = 0.91, P < 0.001) was found between automated and manual MRPI 2.0 values. Conclusions: Our study provides an automated, validated, and generalizable magnetic resonance biomarker to distinguish PSP-P from PD. The use of the automated MRPI 2.0 algorithm rather than manual measurements could be important to standardize measures in patients with PSP-P across centers, with a positive impact on multicenter studies and clinical trials involving patients from different geographic regions. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society
Validity of the wall goniometer as a screening tool to detect postural abnormalities in Parkinson's disease
none24INTRODUCTION: Software-based measurements of postural abnormalities in Parkinson's disease (PD) are the gold standard but may be time-consuming and not always feasible in clinical practice. Wall goniometer (WG) is an easier, quicker, and inexpensive instrument for screening patients with postural abnormalities, but no studies have investigated its validity so far. The aim of this study was to investigate the validity of the WG to measure postural abnormalities. METHODS: A total of 283 consecutive PD outpatients with ≥5° forward trunk, lateral trunk or forward neck bending (FTB, LTB, FNB, respectively) were recruited from seven centers for movement disorders. Postural abnormalities were measured in lateral and posterior view using a freeware program (gold standard) and the WG. Both angles were expressed in degrees (°). Sensitivity and specificity for the diagnosis of camptocormia, Pisa syndrome, and anterocollis were assessed. RESULTS: WG showed good to excellent agreement (intraclass correlation coefficient from 0.80 to 0.98) compared to the gold standard. Bland-Altman plots showed a mean difference between the methods from -7.4° to 0.4° with limits of agreements from -17.7° to 9.5°. Sensitivity was 100% for the diagnosis of Pisa syndrome, 95.74% for anterocollis, 76.67% for upper camptocormia, and 63.64% for lower camptocormia. Specificity was 59.57% for Pisa syndrome, 71.43% for anterocollis, 89.80% for upper camptocormia, and 100% for lower camptocormia. Overall, the WG underestimated measurements, especially in lower camptocormia with an average of -8.7° (90% of cases). CONCLUSION: WG is a valid tool for screening Pisa syndrome and anterocollis, but approximately 10° more should be added for camptocormia.openTinazzi M.; Gandolfi M.; Artusi C.A.; Lanzafame R.; Zanolin E.; Ceravolo R.; Capecci M.; Andrenelli E.; Ceravolo M.G.; Bonanni L.; Onofrj M.; Telese R.; Bertolotti C.; Polverino P.; Manganotti P.; Mazzucchi S.; Giannoni S.; Vacca L.; Stocchi F.; Casali M.; Zibetti M.; Lopiano L.; Fasano A.; Geroin C.Tinazzi, M.; Gandolfi, M.; Artusi, C. A.; Lanzafame, R.; Zanolin, E.; Ceravolo, R.; Capecci, M.; Andrenelli, E.; Ceravolo, M. G.; Bonanni, L.; Onofrj, M.; Telese, R.; Bertolotti, C.; Polverino, P.; Manganotti, P.; Mazzucchi, S.; Giannoni, S.; Vacca, L.; Stocchi, F.; Casali, M.; Zibetti, M.; Lopiano, L.; Fasano, A.; Geroin, C
Does the Degree of Trunk Bending Predict Patient Disability, Motor Impairment, Falls, and Back Pain in Parkinson's Disease?
Background: Postural abnormalities in Parkinson's disease (PD) form a spectrum of functional trunk misalignment, ranging from a “typical” parkinsonian stooped posture to progressively greater degrees of spine deviation. Objective: To analyze the association between degree of postural abnormalities and disability and to determine cut-off values of trunk bending associated with limitations in activities of daily living (ADLs), motor impairment, falls, and back pain. Methods: The study population was 283 PD patients with ≥5° of forward trunk bending (FTB), lateral trunk bending (LTB) or forward neck bending (FNB). The degrees were calculated using a wall goniometer (WG) and software-based measurements (SBM). Logistic regression models were used to identify the degree of bending associated with moderate/severe limitation in ADLs (Movement Disorders Society Unified PD Rating Scale [MDS-UPDRS] part II ≥17), moderate/severe motor impairment (MDS-UPDRS part III ≥33), history of falls (≥1), and moderate/severe back pain intensity (numeric rating scale ≥4). The optimal cut-off was identified using receiver operating characteristic (ROC) curves. Results: We found significant associations between modified Hoehn & Yahr stage, disease duration, sex, and limitation in ADLs, motor impairment, back pain intensity, and history of falls. Degree of trunk bending was associated only with motor impairment in LTB (odds ratio [OR] 1.12; 95% confidence interval [CI], 1.03–1.22). ROC curves showed that patients with LTB of 10.5° (SBM, AUC 0.626) may have moderate/severe motor impairment. Conclusions: The severity of trunk misalignment does not fully explain limitation in ADLs, motor impairment, falls, and back pain. Multiple factors possibly related to an aggressive PD phenotype may account for disability in PD patients with FTB, LTB, and FNB
Do demographic and clinical features and comorbidities affect the risk of spread to an additional body site in functional motor disorders?
The aim of this study is to assess changes in the body distribution and the semeiology of functional motor disorder (FMD) in patients who reported only one or more than one body site affected at FMD onset. Data were obtained from the Italian Registry of Functional Motor Disorders, which included patients with a diagnosis of clinically definite FMDs. The relationship between FMD features and spread to other body sites was estimated by multivariate Cox regression analysis. We identified 201 (49%) patients who reported only one body site affected at FMD onset and 209 (51%) who reported multiple body sites affected at onset. FMD spread from the initial site to another site in 43/201 (21.4%) patients over 5.7 ± 7.1 years in those with only one site affected at FMD onset; FMD spread to an another body site in 29/209 (13.8%) over 5.5 ± 6.5 years. The spread of FMD was associated with non-motor functional symptoms and psychiatric comorbidities only in the patients with one body site affected at FMD onset. Our findings provide novel insight into the natural history of FMD. The number of body sites affected at onset does not seem to have a consistent influence on the risk of spread. Furthermore, our findings suggest that psychiatric comorbidities and non-motor functional symptoms may predict the spread of FMD symptoms, at least in patients with one body site affected at onset
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