Kernel conditional quantile estimation via reduction revisited

Quantile regression refers to the process of estimating the quantiles of a conditional distribution and has many important applications within econometrics and data mining, among other domains. In this paper, we show how to estimate these conditional quantile functions within a Bayes risk minimization framework using a Gaussian process prior. The resulting non-parametric probabilistic model is easy to implement and allows non-crossing quantile functions to be enforced. Moreover, it can directly be used in combination with tools and extensions of standard Gaussian Processes such as principled hyperparameter estimation, sparsification, and quantile regression with input-dependent noise rates. No existing approach enjoys all of these desirable properties. Experiments on benchmark datasets show that our method is competitive with state-of-the-art approaches.

Rescue stenting for failed mechanical thrombectomy procedures

Background: Mechanical thrombectomy (MT) has dramatically changed the natural history of acute ischemic stroke. The disease that was associated with high morbidity, mortality, and significant cost on the health care system became a treatable disease. One of the most important variables to improve outcomes is time to revascularize the ischemic tissue. Rescue stenting (RS) is an option for patients who fail MT. Methods: A retrospective chart review for patients who underwent a MT procedure and either failed (defined as TICI 0-2a) or required a RS from 2015 – 2019 composed the study population. IRB approval was obtained and the consent was waived due to the study design. Medical charts and imaging were reviewed for baseline characteristics, stroke characteristics, complications, and functional outcome. Comparison was performed between the rescue group and the failed group to analyze outcomes. Results: From 2015-2019, 96 patients failed a MT procedure, and 26 patients required an intracranial stent. Initial NIHSS scores were comparable between the groups, (16.1 ± 7.2 vs. 15.2 ± 8.0, p = 0.552). Patients received comparable pre-procedure care as indicated by similar rate of tPA administration (38.5% vs. 34.6%, p = 0.804) and symptom onset to procedure time (1043.5 ± 3556 vs. 1505.3 ± 5183, p = 0.652). While receiving an intracranial stent led to a longer procedure time (66.1 ± 43.4 vs. 86.6 ± 36.2, p = 0.040), patients receiving a stent had a reduced mortality (32 (36.0%) vs. 3 (12.0%), p = 0.027) and NIHSS at discharge (23.0 ± 14.7 vs. 14.5 ± 13.6, p = 0.034). In the RS group, 4 patients had symptomatic intracranial hemorrhage as opposed to 2 in the non-RS group (3.6% vs 15.4%, p = 0.08). Conclusion: Rescue stenting was associated with good outcomes as indicated by decreased mortality and NIHSS at discharge

High-stakes remote-access open-book examinations

The COVID-19 pandemic has led to unprecedented challenges in medical school assessments. Final year high-stakes assessments have classically used closed book examinations (CBEs). Alternative methods of assessment such as open book examinations (OBEs) are emerging but are not routinely used in final year medical school exams. OBEs encourage the use of problem-solving skills more akin to those used in real-life. There is currently limited data comparing OBEs with CBEs. A systematic review showed there was insufficient evidence to support the exclusive use of either CBEs or OBEs in assessment, however the studies conducted to date have rarely looked at high-stakes assessments due to concerns about the validity of OBEs1

Preparing Underrepresented High School Students to Increase Diversity in the Research and Health Professions

This article introduces the work that was done through the Coordinating Center at Charles R. Drew University of Medicine and Science

Improving Serial Imaging Protocols in Spontaneous Intracerebral Hemorrhage

There is no universally agreed upon protocol to image patient presenting with intra-parenchymal hemorrhage of non-traumatic etiology (sICH). At our institution, it is common practice for a patient to have 3 CT’s done within 24 hours. They are often at onset of symptoms or presentation, 6 hours post onset of symptoms, and finally 24 hours post bleed onset. The goal of this project will be to assess the safety and efficacy of obtaining this repeat imaging in our patients in the hopes that limiting unnecessary CT head studies will decrease resource utilization, decrease patient radiation, expedite movement of stable patients out of the ICU and/or disposition

Imaging high-dimensional spatial entanglement with a camera

The light produced by parametric down-conversion shows strong spatial entanglement that leads to violations of EPR criteria for separability. Historically, such studies have been performed by scanning a single-element, single-photon detector across a detection plane. Here we show that modern electron-multiplying charge-coupled device cameras can measure correlations in both position and momentum across a multi-pixel field of view. This capability allows us to observe entanglement of around 2,500 spatial states and demonstrate Einstein-Podolsky-Rosen type correlations by more than two orders of magnitude. More generally, our work shows that cameras can lead to important new capabilities in quantum optics and quantum information science.Comment: 5 pages, 4 figure

Development of a modified SEDEX phosphorus speciation method for ancient rocks and modern iron-rich sediments

We report the development of a modified method for evaluating different reservoirs of sedimentary phosphorus (P) in ancient marine sedimentary rocks and in modern Fe-rich sediments. Utilising the existing SEDEX scheme for P partitioning in modern sediments, we initially demonstrate limitations in the application of the original scheme to sediments and rocks containing crystalline hematite and magnetite. We tested additional extractions for these crystalline Fe phases, using both synthetic minerals, and modern and ancient sediments. The addition of 6 h oxalate and 6 h citrate-dithionate-acetate extractions considerably enhanced the total recovery of synthetic magnetite and hematite to 88.7 ± 1.1% and 76.9 ± 3.8%, respectively. In addition, application of the 6 h oxalate extraction to synthetic P-containing magnetite recovered 93.9 ± 1.7% of the Fe present and 88.2 ± 12.8% of the co-precipitated P. Based upon these results we developed a modified SEDEX extraction scheme. The modified scheme was applied to modern Fe-rich sediments from Golfo Dulce, Costa Rica, which resulted in 16% higher Fe-bound P recovery. Application of the scheme to a variety of ancient marine rocks increased the recovery of Fe-bound P by up to 22%. We also highlight the potential for authigenic carbonate fluorapatite to convert to more crystalline apatite in ancient rocks during deep burial and metamorphism. We suggest that in such systems minimum and maximum estimates of the total reactive P pool may be calculated with and without the inclusion of crystalline P. It is noted that the application of the revised method may have important implications for understanding the cycling of P in ancient marine environments

Hypersexuality, gender, and sexual orientation: a large-scale psychometric survey study

Criteria for Hypersexual Disorder (HD) were proposed for consideration in the DSM-5 but ultimately excluded for a variety of reasons. Regardless, research continues to investigate hypersexual behavior (HB). The Hypersexual Behavior Inventory (HBI) is one of the most robust scales assessing HB, but further examination is needed to explore its psychometric properties among different groups. Therefore, the aim of the present study was to examine the generalizability of the HBI in a large, diverse, nonclinical sample (N = 18,034 participants; females = 6132; 34.0%; Mage = 33.6 years, SDage = 11.1) across both gender and sexual orientation. Measurement invariance testing was carried out to ensure gender- and sexual-orintation based comparisons were meaningful. Results demonstrated when both gender and sexual-orientation were considered (i.e., heterosexual males vs. LGBTQ males vs. heterosexual females vs. LGBTQ females), LGBTQ males had significantly higher latent means on the HBI factors. Results also demonstrated LGBTQ males had the highest scores on other possible indicators of hypersexuality (e.g., frequency of masturbation, number of sexual partners, or frequency of pornography viewing). These findings suggest LGBTQ males may be a group most at risk of engaging in hypersexual behavior and LGBTQ females are at a higher risk of engaging in hypersexual activities due to coping problems. Given the largescale nature of the study, the findings significantly contribute to the currently growing body of literature on hypersexuality

The psychometric properties of the Hypersexual Behavior Inventory using a large-scale nonclinical sample

The conceptualization of hypersexuality has begun to converge as a result of proposed diagnostic criteria. However, its measurement is still diverse. The Hypersexual Behavior Inventory (HBI) is one of the most appropriate scales used to assess hypersexuality, but further examination is needed to test its psychometric properties among different clinical and nonclinical groups, including samples outside of the United States. The aim of the present study was to investigate the reliability and the generalizability of HBI and to determine a cutoff score on a large, diverse, online, nonclinical sample (N = 18,034 participants; females = 6132; 34.0%; Mage = 33.6 years, SDage = 11.1). Confirmatory factor analysis (CFA) and reliability indices provided support for the structure of the HBI and demonstrated excellent reliability. Employing latent profile analysis (LPA), seven classes emerged, but they could not be reliably distinguished by objective sexuality-related characteristics. Moreover, it was not possible to determine an adequate cutoff score, most likely due to the low prevalence rate of hypersexuality in the population. HBI can be reliably used to measure the extent of hypersexual urges, fantasies, and behavior; however, objective indicators and a clinical interview are essential to claim that a given individual may exhibit features of problematic sexual behavior