Hydrothermal fluorite-hematite veins represent a relatively rare vein type, which is sometimes associated with more common, fluorite-barite-quartz‑carbonate veins containing base metal ...mineralization. The origin and significance of the fluorite-hematite veins, and how they relate to the more common expression of mineralization, is essentially unknown. Here, we present new data illuminating the formation conditions of these “sulfide-barren” fluorite-hematite veins in a mining district known for hydrothermal Pb + Zn + Ag ores for which formation conditions are well understood: the Schwarzwald district in SW Germany. The exemplary Ödsbach-Hesselbach vein was chosen to study the fluids involved in fluorite-hematite precipitation through the first, direct investigation of fluid inclusions hosted in hydrothermal hematite using combined infra-red light microscopy, microthermometry and LA-ICPMS. The results indicate that the hematite-precipitating fluids are nearly identical to those observed in the associated fluorite, showing consistent salinities of 24.6–25.0 wt% (NaCl+CaCl2) and homogenization temperatures of 150 to 155 °C. Moreover, the trace element abundances determined by the LA-ICPMS analyses show a composition similar to other inclusions observed in the common mineralization in the mining district, including elevated Pb (>5000 μg/g) and Zn (>2000 μg/g) concentrations at low Cl/Br mass ratios, and sulfur contents mostly below the limits of detection. The results suggest fluid mixing between a continental basement brine and a redbed-derived fluid from the Triassic Buntsandstein. Therefore, the formation of the rare fluorite-hematite veins was probably triggered by a change of the sedimentary fluid endmember representing a shift from the Middle Triassic Muschelkalk fluid, which drove the more common Pb + Zn + Ag mineralization, towards fluids derived from the Buntsandstein. Furthermore, the absence of sulfur is interpreted to have precluded base metal sulfide precipitation, and the formation of hematite points to unusually oxidized conditions and hence towards a lack of a reducing agent, which would also have been required to generate a mineralization of base metal sulfides.
•First LA-ICPMS data from hematite-hosted fluid inclusions•How a missing redox agent influence vein mineralogy.•Low S systems are needed to precipitate fluorite-hematite veins.
The complexity of antiparkinsonian medications makes patients vulnerable to medication deviations. This study examines the frequency and outcomes of deviations between outpatient and inpatient ...medication administrations in patients with Parkinson's disease (PD).
We included hospital admissions of patients with PD during a 12-month period at the Cleveland Clinic Main and Fairview campuses. Outpatient regimens were compared with hospital medication administration records to establish rates of deviations in terms of levodopa equivalent daily dose (LEDD) difference, timing deviations/omissions of time-critical medications, substitution of levodopa compounds, and administration of antidopaminergic medications. Logistic regression analyses were used to investigate associations with length of stay (LOS), readmission rates, and mortality.
The study included 492 patients with 725 admissions. Of those on time-critical medications, 43% had a LEDD deviation and 19% had levodopa formulation substitutions. Of the admission days with known outpatient timing regimens, 47% had an average deviation of more than 30 min and 22% had at least one missed levodopa dose. LOS was longer with each additional day of over-dose (4%), under-dose (14%), missed dose (21%), timing deviation (15%) and substitution (19%), (all p < 0.0001). Administration of antidopaminergic medications (9.9% of admissions) was associated with increased 30-day readmission/death (OR 1.85, p = 0.041), 90-day mortality (OR 2.2, p = 0.018), and LOS (7.6 vs. 3.8 days, p < 0.0001). LEDD underdose was associated with 30-day readmission/death (OR 1.78, p = 0.025) and 90-day mortality (OR 1.14, CI 1.05-1.24, p = 0.002).
Deviations between outpatient and hospital regimens, and administration of antidopaminergic medications, were associated with poor outcomes.
Abstract Background Deep brain stimulation (DBS) of the subthalamic region is an established therapy for advanced Parkinson's disease (PD). However, patients often require time-intensive ...post-operative management to balance their coupled stimulation and medication treatments. Given the large and complex parameter space associated with this task, we propose that clinical decision support systems (CDSS) based on machine learning algorithms could assist in treatment optimization. Objective Develop a proof-of-concept implementation of a CDSS that incorporates patient-specific details on both stimulation and medication. Methods Clinical data from 10 patients, and 89 post-DBS surgery visits, were used to create a prototype CDSS. The system was designed to provide three key functions: 1) information retrieval; 2) visualization of treatment, and; 3) recommendation on expected effective stimulation and drug dosages, based on three machine learning methods that included support vector machines, Naïve Bayes, and random forest. Results Measures of medication dosages, time factors, and symptom-specific pre-operative response to levodopa were significantly correlated with post-operative outcomes ( P < 0.05) and their effect on outcomes was of similar magnitude to that of DBS. Using those results, the combined machine learning algorithms were able to accurately predict 86% (12/14) of the motor improvement scores at one year after surgery. Conclusions Using patient-specific details, an appropriately parameterized CDSS could help select theoretically optimal DBS parameter settings and medication dosages that have potential to improve the clinical management of PD patients.
Background
Magnetic resonance elastography (MRE) is an imaging technique that can noninvasively assess the shear properties of the intervertebral disc (IVD). Unlike the standard gradient recalled ...echo (GRE) MRE technique, a spin‐echo echo‐planar imaging (SE‐EPI) sequence has the potential to improve imaging efficiency and patient compliance.
Purpose
To validate the use of an SE‐EPI sequence for MRE of the IVD compared against the standard GRE sequence.
Study Type
Cross‐over.
Subjects
Twenty‐eight healthy volunteers (15 males and 13 females, age range: 19–55).
Field Strength/Sequence
3 T; GRE, SE‐EPI with breath holds (SE‐EPI‐BH) and SE‐EPI with free breathing (SE‐EPI‐FB) MRE sequences.
Assessment
MRE‐derived shear stiffnesses were calculated via principal frequency analysis. SE‐EPI derived shear stiffness and octahedral shear strain signal‐to‐noise ratios (OSS‐SNR) were compared against those derived using the GRE sequence. The reproducibility and repeatability of SE‐EPI stiffness measurements were determined. Shear stiffness was evaluated in the nucleus pulposus (NP) and annulus fibrosus (AF) regions of the disc. Scan times between sequences were compared.
Statistical Tests
Linear mixed models, Bland–Altman plots, and Lin's concordance correlation coefficients (CCCs) were used with P < 0.05 considered statistically significant.
Results
Good correlation was observed between shear stiffnesses derived from the SE‐EPI sequences with those derived from the GRE sequence with CCC values greater than 0.73 and 0.78 for the NP and AF regions, respectively. OSS‐SNR was not significantly different between GRE and SE‐EPI sequences (P > 0.05). SE‐EPI sequences generated highly reproducible and repeatable stiffness measurements with CCC values greater than 0.97 in the NP and AF regions and reduced scan time by at least 51% compared to GRE. SE‐EPI‐BH and SE‐EPI‐FB stiffness measurements were similar with CCC values greater than 0.98 for both regions.
Data Conclusion
SE‐EPI‐based MRE‐derived stiffnesses were highly reproducible and repeatable and correlated with current standard GRE MRE‐derived stiffness estimates while reducing scan times.
Level of Evidence
1
Technical Efficacy Stage
1
Mixing of sedimentary formation fluids with basement-derived brines is an important mechanism for the formation of hydrothermal veins. We focus on the sources of the sediment-derived fluid component ...in ore-forming processes and present a comprehensive fluid inclusion study on 84 Jurassic hydrothermal veins from the Schwarzwald mining district (SW Germany). Our data derive from about 2300 fluid inclusions and reveal differences in the average fluid composition between the northern, central, and southern Schwarzwald. Fluids from the northern and southern Schwarzwald are characterised by high salinities (18–26 wt% NaCl+CaCl
2
), low Ca/(Ca+Na) mole ratios (0.1–0.4), and variable Cl/Br mass ratios (30–1140). In contrast, fluids from the central Schwarzwald show even higher salinities (23–27 wt% NaCl+CaCl
2
), higher Ca/(Ca+Na) mole ratios (0.2–0.9), and less variable Cl/Br mass ratios (40–130). These fluid compositions correlate with the nature and thickness of the now eroded sedimentary cover rocks. Compared to the northern and the southern Schwarzwald, where halite precipitation occurred during the Middle Triassic, the sedimentary basin in the central Schwarzwald was relatively shallow at this time and no halite was precipitated. Accordingly, Cl/Br ratios of fluids from the central Schwarzwald provide no evidence for the reaction of a sedimentary brine with halite, whereas those from the northern and southern Schwarzwald do. Instead, elevated Ca/(Ca+Na), high SO
4
contents, and relatively low Cl/Br imply the presence of a gypsum dissolution brine during vein formation in the central Schwarzwald which agrees with the reconstructed regional Triassic geology. Hence, the information archived in fluid inclusions from hydrothermal veins in the crystalline basement has the potential for reconstructing sedimentary rocks in the former overburden.
Background: Depression has been estimated to affect 1 in 3 individuals with Parkinson's disease (PD) and can lead to worse health outcomes and decreased quality of life. Anxiety further complicates ...PD outcomes. Pharmacologic treatments of depression and anxiety can have negative side effects in patients with PD, including exacerbation of PD symptoms. There is a critical need for alternative treatment approaches that address depression and anxiety among patients with PD. Psychosocial or behavioral approaches are known to be effective for depression generally, but only a handful of studies have examined the role of psychosocial treatments of patients with depression in PD. Objective: The aim of this article was to review published psychosocial treatment studies of depression and anxiety in patients with PD. Methods: The PubMed database was searched for articles published in English before April 2011 using the terms Parkinson’s disease, depression, anxiety, psychotherapy, cognitive therapy, behavioral treatment, behavioral therapy, nonpharmacologic treatment, psychoeducation, education, psychosocial treatment, and stress management. Articles included were prospective clinical trials utilizing specific depression or anxiety assessments as primary or secondary outcomes in patients with PD. Results: Nine reports derived from 8 separate studies fit the inclusion criteria and were included in this review. All studies were published between 1997 and 2011, and all but 3 had small sample sizes (<40 patients). Interventions included cognitive behavioral therapy (CBT), psychodrama, education, and behavior therapy as well as multidisciplinary rehabilitation. Cognitive behavioral therapy was the most studied and was shown to decrease depressive and anxiety symptoms in patients with PD. Other individual and group therapies may improve depression and anxiety in patients with PD, but the general paucity of studies and study methods limit the interpretation of these results. Conclusions: There have been few studies on psychosocial treatments that specifically assess change in depression and anxiety among patients with PD. While results for CBT and other modes of therapy are promising for acute management of depression and anxiety, longer term effects after treatment have been variable. There is a need for additional studies on psychosocial interventions in people with PD.
We propose a model that uses the exchange rate of Bitcoin against the US dollar to predict the computing power of Bitcoin’s network. We show that free entry places an upper bound on mining revenues ...and explain how it can be identified. Calibrating the model’s parameters allows us to accurately forecast the evolution of the network computing power over time. We find that a significant share of mining rewards was invested in mining equipment and that the seigniorage income of miners was limited.
Although ethical scandals are a common phenomenon in the service industry, there is little research on the service-specific aspects of crisis management. In this research, we argue that frontline ...employees are of crucial importance after a scandal and examine how firms can secure the support of frontline employees following different kinds of scandals. Specifically, we demonstrate that corrective responses that address the internal causes of a scandal and ceremonial responses that guide attention to positive aspects unrelated to the scandal moderate the impact of different scandals on frontline employee support. Three experiments showed that frontline employee support was greater after scandals that involved a great rather than a small number of wrongdoers and after scandals that had been caused by high-ranking managers rather than low-ranking employees when a corrective response was implemented. In contrast, support was greater following scandals that had been committed by a few low-ranking employees rather than high-ranking managers when a ceremonial response was employed. These results have important implications by illustrating how companies can effectively restore frontline employee support following a scandal.
In practical applications of image classification, methods based on convolutional neural networks are used as standard nowadays. However, the success of these methods is not explained sufficiently ...from a theoretical point of view. For this, a statistical model for image classification, namely a hierarchical max-pooling model with additional local pooling, is introduced. Here the additional local pooling enables the hierarchical model to combine parts of the image which have a variable relative distance towards each other. Various convolutional neural network image classifiers are introduced and analyzed in view of their rate of convergence of the misclassification risk of the estimates towards the optimal misclassification risk. This analysis provides a theoretical explanation why general convolutional neural network architectures that include some kind of local pooling layers are useful in some image classification situations and gives theoretical hints for choosing the right network architecture. Furthermore, the finite sample size performance of these network architectures is illustrated by applying them to simulated and real data.
•Convolutional neural network image classifiers circumvent curse of dimensionality.•Pooling and subsampling layers are useful from a theoretical point of view.•Statistical model where objects have variable relative distances towards each other.•Rate of convergence results for three convolutional neural network architectures.•Finite sample size performance by application to simulated and real data.
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