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We propose, a heterogeneous simultaneous multiscale change point estimator called ‘H-SMUCE’ for the detection of multiple change points of the signal in a heterogeneous Gaussian regression model. A piecewise constant function is estimated by minimizing the number of change points over the acceptance region of a multiscale test which locally adapts to changes in the variance. The multiscale test is a combination of local likelihood ratio tests which are properly calibrated by scale-dependent critical values to keep a global nominal level α, even for finite samples. We show that H-SMUCE controls the error of overestimation and underestimation of the number of change points. For this, new deviation bounds for F-type statistics are derived. Moreover, we obtain confidence sets for the whole signal. All results are non-asymptotic and uniformover a large class of heterogeneous change point models. H-SMUCE is fast to compute, achieves the optimal detection rate and estimates the number of change points at almost optimal accuracy for vanishing signals, while still being robust. We compare H-SMUCE with several state of the art methods in simulations and analyse current recordings of a transmembrane protein in the bacterial outer membrane with pronounced heterogeneity for its states. An R-package is available on line.

[This corrects the article DOI: 10.3389/fphar.2021.732698.].

Background: Critical value notification (CVN) entails notifying doctors or other laboratory users of aberrant laboratory results that threaten the patient’s life and of any values for which reporting delays could negatively impact the patient’s health. Critical value notification practices in clinical laboratories in Nigeria and sub-Saharan Africa are largely unknown. Objective: We conducted a nationwide survey to obtain baseline information on CVN practice by Nigeria’s laboratories. Methods: This cross-sectional study was conducted among purposively selected secondary- and tertiary-tier, public and private clinical laboratories across northern and southern Nigeria between October 2015 and December 2015. Consenting senior laboratory staff completed and returned a structured questionnaire, that gathered data on respondents’ demographics, designations, and institutional characteristics and practices regarding CVN. Results: One hundred and thirty-four laboratories responded to the questionnaires. Only 69 (51.5 %) laboratories practised CVN; only 23 (33.3%) had existing written policies guiding the practice. Most (43; 62.3%) laboratories use similar critical values (CVs) for adult and paediatric populations. Most laboratories (27; 39.1%) obtained their CVs by combining published literature and local opinions from stakeholders. Physical dispatch (42; 60.9%) followed by telephone calls (38; 55.1%) were the most common means of notification. Private laboratories, compared with public hospital laboratories, were likelier to have separate paediatric CV lists ( p = 0.019) and practise telephone notifications ( p < 0.001). Conclusion: Critical value notification practices vary and are often suboptimal in many clinical laboratories in Nigeria, which is exacerbated by the absence of guiding policies and national recommendations for post-analytical procedures. What this study adds: This study provides baseline information on CVN practice by Nigeria’s laboratories. The study explores the causes of practice variations that can serve as a foundation for enhancing critical reporting and post-analytical services, particularly in clinical laboratories in sub-Saharan Africa.

One of the most important aspects of post-analytical laboratory activity is the notification of critical results. Therefore, the aim of this study was to illustrate and analyze the prevalence of critical result values of our clinical laboratory investigations during the pandemic stages of coronavirus-19 (COVID-19) and other research pre-pandemic stages. The seven-month study was conducted between May 2020 and November 2020. Laboratory data of critical results were collected in this retrospective cohort. In total, 221,384 routine tests and 84,451 STAT tests were performed in our clinical laboratory. Of the 3183 (1.44%) tests result was identified as having Critical values, consisting of 2220 (69.74%) and 963 (30.25%) tests in biochemistry and hematology assays. Among the tests with critical values, 39.6% of which were from emergency department (ED) as STAT testing (1262) and 60.3% (1921) as TAT testing. Testing was found in routine inpatients and outpatients, 58% and 2.3%, respectively, and the most frequent parameter notified was sodium. In our practice, we observed that the higher level of frequency of critical values results is related to inpatients, contradicting several researchers reporting that the higher percentages of critical values were from ED.

The critical value of soil Olsen-P is the point above which the probability of crop yield response to fertilizer P is small or nil. Determining this critical value is fundamental when making appropriate P fertilizer recommendations. In this study, the critical values were determined for continuous maize (Zea mays L.)-winter wheat (Triticum aestivum L.) cropping systems from a 15-year field experiment across three sites in China using linear-linear, linear-plateau and Mitscherlich models. The mean critical values for maize using the three models ranged from 12.1 to 17.3 mg P kg⁻¹ (average 15.3 mg P kg⁻¹) and for winter wheat from 12.5 to 19.0 mg P kg⁻¹ (average 16.3 mg P kg⁻¹) among study sites. The mean critical value for maize was approximately 7% lower than that for winter wheat across all sites based on the three models. Critical values identified by the Mitscherlich model were 1.4 to 2.1 times those from linear-linear and 1.3 to 1.9 times of those from linear-plateau and were crop and site dependent. There was a significant negative correlation (P < 0.05) between the mean critical value from the three models and the observed P uptake by either maize or wheat. Our study shows that the critical values can vary with sites, crops and models used, and thus caution should be taken when selecting the most appropriate one when making P fertilizer recommendations for agronomic return and to minimize chances of negative environment impact from overfertilization.

Background: To improve communication between clinical providers and the laboratory, we recently implemented secure text messaging for our critical value notifications. This was done to communicate laboratory critical values (CV) to providers faster so changes to patient care could be done faster. Our previous method of communicating CV to providers was paging and relied on a call back to receive the critical value. Methods: We implemented delivery of CV through a secure texting application in which the CV was directly communicated to the provider on their smart phone device. Results: The mean pre-implementation turnaround time (TAT) was 11.3 minutes (median: 7 minutes, range: 0 - 210 minutes). The mean post- secure text messaging implementation TAT was 3.03 minutes (median: 0.89 minutes, range: < 1 - 95 minutes).When comparing pre- and post-implementation, there was a significant reduction in the TAT from using secure text messaging (p < 0.001). Of the 234 surveys sent out, 81 providers responded (35%). Of these responses, 85% reported that critical value notification by secure text messaging has increased their efficiency and 95% reported that critical value notification is more effective than a pager-phone-call based system. 83% of providers reported that they were able to provide better, faster care to their patients. Conclusions: Using secure text messaging (STM) to deliver critical values significantly reduces the CV TAT. Furthermore, providers noted they preferred to receive CV notifications through STM and reported that they were able to provide more effective care to their patients.

We analyze use of a quasi-likelihood ratio statistic for a mixture model to test the null hypothesis of one regime versus the alternative of two regimes in a Markov regime-switching context. This test exploits mixture properties implied by the regime-switching process, but ignores certain implied serial correlation properties. When formulated in the natural way, the setting is nonstandard, involving nuisance parameters on the boundary of the parameter space, nuisance parameters identified only under the alternative, or approximations using derivatives higher than second order. We exploit recent advances by Andrews (2001) and contribute to the literature by extending the scope of mixture models, obtaining asymptotic null distributions different from those in the literature. We further provide critical values for popular models or bounds for tail probabilities that are useful in constructing conservative critical values for regime-switching tests. We compare the size and power of our statistics to other useful tests for regime switching via Monte Carlo methods and find relatively good performance. We apply our methods to reexamine the classic cartel study of Porter (1983) and reaffirm Porter's findings.

The authors used a validated model with electronic-medical-record data to identify hospitalized patients at high risk for clinical deterioration. The intervention, which involved remote monitoring by nurses who reviewed records of high-risk patients and communicated with in-hospital rapid-response teams, was associated with decreased 30-day mortality.

Turán's theorem is a cornerstone of extremal graph theory. It asserts that for any integer r ≥ 2, every graph on n vertices with more than $\\frac{{r - 2}}{{2\\left( {r - 1} \\right)}} \\cdot {n^2}$ edges contains a clique of size r, i.e., r mutually adjacent vertices. The corresponding extremal graphs are balanced (r – 1)-Partite graphs. The question as to how many such r-cliques appear at least in any n-vertex graph with γn² edges has been intensively studied in the literature. In particular, Lovász and Simonovits conjectured in the 1970's that asymptotically the best possible lower bound is given by the complete multipartite graph with γn² edges in which all but one vertex class is of the same size while the remaining one may be smaller. Their conjecture was recently resolved for r = 3 by Razborov and for r = 4 by Nikiforov. In this article, we prove the conjecture for all values of r.

Since laboratory critical values reflect such an abnormal pathologic state that there is imminent danger to the patient, it is crucial to deliver the result upon initial call with an escalation process when the initial call cannot occur. In our 8-hospital system, one of the hospitals used the escalation procedure twice as frequently compared with the other hospitals. This work presents hospital-wide quality improvement processes that decreased escalation of critical value calls so as to reach the same proportion of escalated calls compared to other hospitals in the system. The laboratory met weekly with leaders of different hospital areas and quality management; they presented the interventions they implemented, and the laboratory monitored their progress. Monitoring and reviewing with providers the importance of critical values decreased temporarily escalated calls from 25% to 18%. Having a dedicated phone to call critical values in each hospital area decreased the calls in a sustained fashion, which now fluctuate between 9% and 14%. Other interventions, including having a dedicated person receiving critical value results, did not decrease escalated critical value calls. Having a dedicated phone in each hospital area that receives the initial critical value call simplifies and standardizes the process.