To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Background: The aim of this study is to assess factors impacting the postoperative length of stay (LOS) for patients undergoing microvascular decompression (MVD) surgery. Methods: A consecutive series of patients undergoing MVD at the Winnipeg Centre for Cranial Nerve Disorders were reviewed. All patients were monitored in a neurosurgical stepdown unit for at least 6 hours postoperatively and when medically stable discharged at their own discretion. The hospital LOS was measured in hours from midnight after day of surgery and categorized by days in hospital. Results: The 112 patients included 53 Manitobans (MB) and 59 from out of province (OOP). The overall LOS was 38±52 hours, and not significantly different between genders, diagnosis or age. LOS was significantly shorter for OOP versus MB patients (28±23/48±71 hours; p=0.02). OOP patients were also more often discharged on the first postoperative day (59% versus 32%; p=0.02) and 85% of them stayed at the hotel within the hospital complex prior to travelling home. Conclusions: Postoperative discharge to an adjacent hotel appears to have led to shorter LOS. These patients may have been reassured by the physical proximity to medical care. The utilization of discharge to an adjacent hotel or comparable faculty may reduce hospitalization days and associated costs.
An automated approach to fully reconstruct spherical Kikuchi maps from experimentally collected electron backscatter diffraction patterns and overlay each pattern onto its corresponding position on a simulated Kikuchi sphere is presented in this study. This work demonstrates the feasibility of warping any Kikuchi pattern onto its corresponding location of a simulated Kikuchi sphere and reconstructing a spherical Kikuchi map of a known phase based on any set of experimental patterns. This method consists of the following steps after pattern collection: (1) pattern selection based on multiple threshold values; (2) extraction of multiple scan parameters and phase information; (3) generation of a kinematically simulated Kikuchi sphere as the “skeleton” of the spherical Kikuchi map; and (4) overlaying the inverse gnomonic projection of multiple selected patterns after appropriate pattern center calibration and refinement. The proposed method is the first automated approach to reconstructing spherical Kikuchi maps from experimental Kikuchi patterns. It potentially enables more accurate orientation calculation, new pattern center refinement methods, improved dictionary-based pattern matching, and phase identification in the future.
Increasingly, products are designed for global markets, yet studies of design practices primarily investigate designers from high-income countries. Specifically, the use of prototypes during design is likely affected by the background of the designer and the environment in which they are designing. To broaden our understanding of the extent to which prototyping best practices are used beyond Western designers, in this study, we conducted interviews with novice designers from Ghana, a middle-income country (MIC), to examine how Ghanaian novice designers (upper-level undergraduate students) used prototypes throughout their design courses. We compared the reported use of prototypes to best practice behaviors and analyzed the types of prototypes used. We found evidence that these Ghanaian novice designers used some critical prototyping best practice behaviors, while other behaviors were underutilized, specifically during the front-end phases of design and for the purpose of engaging with stakeholders. Additionally, virtual models dominated their prototyping choices. We discuss likely reasons for these trends based on participants’ design experiences and design contexts.
A Fortran program for analysis of spectra obtained in proton induced x-ray emission spectroscopy is under development. The first version is working and some results are shown. The program uses a model which describes the physics involved in the analysis. The continuum is described by an exponentially decreasing function representing secondary electron induced bremsstrahlung and a constant approximating different Compton scattering processes. Absorption effects are also included. All parameters in the model are fitted simultaneously. About 100 test runs have been made with good results. The continuum was accurately fitted for each spectrum. Other advantages are reliability, speed, and the fact that the program is easily adaptable to a small computer with 16K memory.
REX is a Fortran program for analysis of spectra obtained in PIXE analysis. The underlying model is still under development; however, one year of experience has demonstrated REX's capability to be a fast reliable tool. The modeling of the different components and effects of the physical model is briefly discussed. Evidence is shown that secondary effects mostly due to Compton-scattering in and around the detector are important factors. In order to assure that heavy elements are recorded with sufficient sensitivity during short bombardment times, low energy X-rays are suppressed but not completely absorbed by use of a Mylar absorber with a hole. Such an absorber sometimes introduces severe problems for other techniques of spectrum analysis. However, to REX there is only the job to find the transmission curve of the absorber.
Analysis of multi-layer thin films by XRF, using the fundamental parameter method, is a common and accurate method to determine thicknesses and chemical structure, as long as the films contain no hght elements. As an attempt to further extend the method, we present experimental results from single layer films made of carbon and silicon nitride with thicknesses ranging from 100 Å to 1000 Å, from single layer films of cobalt and oxygen matrices with varying oxygen concentration, and from complex multi-layer structures made of a combination of palladium, copper and carbon. The experimental data show a significant deviation from the results computed by the standard fundamental parameter method.
The St. Louis aerosol was sampled during the period 16-22 August 1973 simultaneously at two locations using cascade impactors for sequential 12-hour samples. The six particle size fractions of each sampling were individually analyzed using PIXE for elements from S to Br and beyond and for heavy elements including Pb which permitted time variations of concentrations and particle size distributions to be followed and related to meteorological changes during the sampling period. In addition, the data were compared with average levels of the elements in coastal north Florida and maritime Bermuda as well as at a third St. Louis site. From this it appeared that some of the concentrations in St. Louis were at natural levels whereas others appeared to be higher and linked to air pollution sources. These relationships and others in this study may lead to criteria for distinguishing between pollutants and natural background in urban aerosols.
The characterization of multi-layer thin film properties, such as thicknesses of layers or concentrations of elements, using the fundamental parameter method is discussed. Experimental results are shown for repetitive multi-layers of up to 80 layers. Furthermore the impact of using different characteristic lines on the information depth and the resolving power is discussed for single layers and repetitive multi-layers. Finally, thin films containing light elements are presented; in this case the conventional fundamental parameter theory fails to provide accurate results, perhaps due to the neglect of the impact of the secondary excitation by photoelectrons.
In the current work an attempt was made to apply the fundamental parameter method to the analysis of boron, oxygen, fluorine and heavier components of silica glasses. Experimental results are presented and compared with calculations based on theoretical work. The specimens consist of sets of certified standards which were obtained from Breitlahder company, Germany.
Furthermore, it is shown that the match between the certified compositions and fundamental parameter computations is affected by the quality of available fundamental parameters for the ultralight elements as well as by the underlying mathematical models. Especially in quantitative analysis of these elements, a large variety of secondary enhancement effects must be taken into account. Two major mechanisms have been considered in the presented computations: excitation by fluorescence photons emitted from aiJ available excited atoms, and excitation by photoelectrons ejected after the primary ionization event. Their magnitude exceeds that of the conventional energy region by far and thus uncertainities in the corrective algorithms have a large effect,
Increased neural error-signals have been observed in obsessive-compulsive disorder (OCD), anxiety disorders, and inconsistently in depression. Reduced neural error-signals have been observed in substance use disorders (SUD). Thus, alterations in error-monitoring are proposed as a transdiagnostic endophenotype. To strengthen this notion, data from unaffected individuals with a family history for the respective disorders are needed.
The error-related negativity (ERN) as a neural indicator of error-monitoring was measured during a flanker task from 117 OCD patients, 50 unaffected first-degree relatives of OCD patients, and 130 healthy comparison participants. Family history information indicated, that 76 healthy controls were free of a family history for psychopathology, whereas the remaining had first-degree relatives with depression (n = 28), anxiety (n = 27), and/or SUD (n = 27).
Increased ERN amplitudes were found in OCD patients and unaffected first-degree relatives of OCD patients. In addition, unaffected first-degree relatives of individuals with anxiety disorders were also characterized by increased ERN amplitudes, whereas relatives of individuals with SUD showed reduced amplitudes.
Alterations in neural error-signals in unaffected first-degree relatives with a family history of OCD, anxiety, or SUD support the utility of the ERN as a transdiagnostic endophenotype. Reduced neural error-signals may indicate vulnerability for under-controlled behavior and risk for substance use, whereas a harm- or error-avoidant response style and vulnerability for OCD and anxiety appears to be associated with increased ERN. This adds to findings suggesting a common neurobiological substrate across psychiatric disorders involving the anterior cingulate cortex and deficits in cognitive control.
We aimed to interrogate the Canadian Institute for Health Information (CIHI) database in order to determine the geographic distribution and outcomes of microvascular decompression (MVD) for the treatment of hemifacial spasm (HFS).
The CIHI database was searched from 2004 to 2017 for relevant diagnostic and procedure codes. A new database was populated with the following categories: year, institution, province, number of interventions per year, and mean length of stay. Descriptive statistics were generated. Provincial utilization rates of MVD for HFS were calculated.
During the period 2004-17, we identified 671 MVDs performed for HFS at 20 centers across Canada. During the study period, 286 MVDs (42.6%) were performed at one center in Manitoba. Another 131 (19.5%) and 72 (10.7%) were performed at one center in British Columbia and Ontario, respectively. The remaining 182 (27.1%) MVDs for HFS were performed at 17 centers across the rest of Canada where the mean number of cases performed per year was 1.1 (SD=0.9, range 0.2-2.9). When out-of-province cases were re-allocated to place of residence, the adjusted provincial utilization of MVD for HFS ranged between 0.5 and 6.1 patients per million per year.
Microvascular decompression for HFS is performed relatively rarely and there is a tremendous geographic variation in utilization across Canada. Although most of these surgeries are performed by a few surgeons, more than half of Canadian centers perform an average of less than 1 case per year. Further examination of the impact of these discrepancies appears warranted.
We introduce a new flexible paradigm of grounding and solving in Answer Set Programming (ASP), which we refer to as multi-shot ASP solving, and present its implementation in the ASP system clingo. Multi-shot ASP solving features grounding and solving processes that deal with continuously changing logic programs. In doing so, they remain operative and accommodate changes in a seamless way. For instance, such processes allow for advanced forms of search, as in optimization or theory solving, or interaction with an environment, as in robotics or query answering. Common to them is that the problem specification evolves during the reasoning process, either because data or constraints are added, deleted, or replaced. This evolutionary aspect adds another dimension to ASP since it brings about state changing operations. We address this issue by providing an operational semantics that characterizes grounding and solving processes in multi-shot ASP solving. This characterization provides a semantic account of grounder and solver states along with the operations manipulating them. The operative nature of multi-shot solving avoids redundancies in relaunching grounder and solver programs and benefits from the solver's learning capacities. clingo accomplishes this by complementing ASP's declarative input language with control capacities. On the declarative side, a new directive allows for structuring logic programs into named and parameterizable subprograms. The grounding and integration of these subprograms into the solving process is completely modular and fully controllable from the procedural side. To this end, clingo offers a new application programming interface that is conveniently accessible via scripting languages. By strictly separating logic and control, clingo also abolishes the need for dedicated systems for incremental and reactive reasoning, like iclingo and oclingo, respectively, and its flexibility goes well beyond the advanced yet still rigid solving processes of the latter.
Background: MS related trigeminal neuralgia (MS-TN) is associated with high recurrence and retreatment rates. Optimal treatment and role for partial sensory rhizotomy (PSR) for MS-TN remains to be determined. Methods: We analyzed time to treatment failure (TTF) after PSR (n=14) versus other prior procedures (n=53) among 12 consecutively treated MS-TN patients. Kaplan-Meier curves and Log-Rank tests were utilized to compare BNI pain scores and TTF after PSR vs prior procedures using the same patient cohort as their own control group. Subsequent analysis compared TTF after PSR to other procedures (n=93) among a second cohort of 18 MS-TN patients not undergoing PSR. Results: TTF was significantly longer after PSR compared to prior procedures among the PSR cohort (p<0.0001) with median TTF of 79 vs 10 months respectively. Similarly, there was a longer TTF after PSR compared to prior procedures among the MS-TN cohort with median TTF 79 vs 16 months respectively (p<0.001). PSR resulted in a higher proportion of excellent pain scores when compared to prior procedures in the MS-TN cohort (77% vs 29%, p<0.001). Conclusions: TTF was significantly longer following partial sensory rhizotomy compared to other prior procedures in MS-TN patients. A higher proportion of patients achieved excellent BNI pain scores after PSR.