Volatility as an Asset Class – A Valuable Portfolio Diversifier in Volatile Times?

This article examines the feasibility of usingvolatility as an asset class to diversify equity portfolios. Especiallyexchange-traded volatility products targeted at retail investorspromise convenient but effective equity hedging. This study looksunder the surface of these seemingly simple products, andbacktests them in extensive portfolio diversification studies. Weapply a wide range of test settings, including different volatilityweights, product maturities, time periods, rebalancing patterns,and dynamic allocation strategies while adopting the perspectiveof U.S. equity investors over the volatile period from 2006 to2011. We find that volatility exposures of up to 10%,implemented through mid-term volatility products or with astraightforward dynamic allocation strategy based on detectingtrends in implied volatility, would have benefited equityportfolios in most scenarios

Cluster Headache and the Comprehension Paradox

Patients with primary headache disorders such as cluster headache cycle between being entirely healthy and almost completely incapacitated. Sick leave or reduced performance due to headache attacks demands flexibility by their social counterparts. The objective of this study is to test the hypothesis that headache patients cause frustration that grows with the times colleagues have to take over their work. In this study, we analysed cluster headache patients’ answers to an online questionnaire. Participants self-reported their number of sick days, the number of days on which leisure activities were missed and whether they felt understood by colleagues and family. We then investigated the correlation between the number of sick days and the proportion of patients feeling understood by colleagues and friends. We found that feeling understood by colleagues and friends decreases with a growing number of sick days. However, when sick days accrue further, this proportion increases again. The number of sick days correlates similarly with both colleagues’ and friends’ understanding. The number of cluster headache patients feeling understood by others decreases with an increasing number of sick days. Their social circles’ frustration with the patients’ failure to meet obligations and expectations are a likely reason. With a growing number of sick days, however, the portion of patients feeling understood rises again despite patients meeting others’ expectations even less. This ‘comprehension paradox’ implies the influence of other factors. We suspect that growing numbers of sick days foster understanding as the disability of the disease becomes increasingly apparent

The Loneliness of Migraine Scale: A Development and Validation Study

Patients with migraine often isolate themselves during their attacks. This disease-related loneliness seems to reverberate interictal, as some patients report failing relationships, losing jobs, or suffering from reduced social contacts. We developed a 10-item self-report questionnaire, the loneliness of migraine scale (LMS), and conducted an online survey. The questionnaire comprised diagnostic questions for migraine, the loneliness of migraine scale, the Generalized Anxiety Disorder Scale (GAD-7), the Patient Health Questionnaire (PHQ-8), and the Headache Attributed Lost Time Index (HALT-90). We computed item statistics, the psychometric properties of the LMS and assessed correlations between loneliness, migraine days, anxiety, and depression. We included 223 participants with (probable) migraine, reporting 8 ± 6 headache days with a disease duration of 11 ± 11 years. The mean scores of the HALT were 88 ± 52, of the GAD-7 10 ± 5, for PHQ-8 11 ± 6, and of the LMS 28.79 ± 9.72. Cronbach’s alpha for all ten items was 0.929. The loneliness scale correlated with the GAD-7 (r = 0.713, p < 0.001), with the PHQ-8 scale (r = 0.777, p < 0.001) and with migraine days (r = 0.338, p < 0.001). The LMS is a reliable and valid questionnaire measuring the loneliness of migraine patients. Feelings of loneliness were common and correlated highly with migraine days, anxiety, and depression

Interrater agreement in headache diagnoses

Background: Diagnosing headache disorders comprises the collection and interpretation of information. This study estimates agreement and bias in the latter. Methods: Physicians and medical students diagnosed eight patients’ headaches using the International Classification of Headache Disorders. We calculated Cohen’s Kappa for all participants and subgroups (board-certified neurologists, physicians working in a neurology department). Moreover, we asked how sure they felt about their diagnoses. Finally, participants estimated the number of different headache diagnoses a patient receives when consulting many physicians for the same headache and indicated the highest acceptable number. Results: The data of 63 participants entered the analysis, of whom 18 were neurologists (18/63, 28.6%), and 41 were currently working at a neurology clinic (41/63, 66.7%). Cohen’s Kappa decreased (0.706, 0.566, and 0.408) with increasing levels of the classification hierarchy. Interrater agreement was highest among neurologists. Physicians not working in a neurology clinic tended to diagnose secondary headaches more often were less confident about their diagnoses. Conclusions: Physicians with less experience in headache disorders struggle more to diagnose headaches than neurologists do; they suspect secondary headaches, disagree, and feel insecure more often. Thus, interpreting a headache history is prone to error and bias

Plasma Spraying of a Microwave Absorber Coating for an RF Dummy Load

The European fusion reactor research facility, called International Thermonuclear Experimental Reactor (ITER), is one of the most challenging projects that involves design and testing of hundreds of separately designed reactor elements and peripheric modules. One of the core elements involved in plasma heating are gyrotrons. They are used as a microwave source in electron–cyclotron resonance heating systems (ECRH) for variable injection of RF power into the plasma ring. In this work, the development and application of an alumina-titania 60/40 mixed oxide ceramic absorber coating on a copper cylinder is described. The cylinder is part of a dummy load used in gyrotron testing and its purpose is to absorb microwave radiation generated by gyrotrons during testing phase. The coating is applied by means of atmospheric plasma spraying (APS). The absorber coating is deposited on the inner diameter of a one-meter cylindrical tube. To ensure homogeneous radiation absorption when the incoming microwave beam is repeatedly scattered along the inner tube surface, the coating shows a varying thickness as a function of the tube length. By this it is ensured that the thermal power is distributed homogeneously on the entire inner tube surface. This paper describes a modeling approach of the coating thickness distribution, the manufacturing concept for the internal plasma spray coating and the coating characterization with regard to coating microstructure and microwave absorption characteristics

Mammalian Cell Viability Methods in 3D Scaffolds for Tissue Engineering

Modern methods have evolved in tissue engineering to evaluate cell viability (CV) in 3D scaffolds and tissues. These involve either the usage of 3D confocal laser microscopy of live or fixed tissues, or separation of cells from the tissue, either live or fixed, and then their analysis by flow cytometry. Generally, working with live cells has the disadvantage that all the scanning needs to be completed immediately at the end of an experiment. Two different approaches can be distinguished: staining intact cell membranes and staining fixed cells. The entire cytoplasm is stained with amine-reactive dyes (ARDs), these use the principle of dead cell exclusion. Here, we list and compare live-cell versus fixed-cells fluorescence-based methods and also show their limitations, especially when working with autofluorescent or cross-linking materials like silk or genipin-reinforced hydrogels. Microscopic techniques have the advantage over flow cytometry-based methods in that these provide the spatial distribution and morphology of the cells. Calcein AM combined with ethidium-homodimer works for most 3D constructs, where no strong fluorescent background is found on the tissue or scaffold. Frequently, however, concentrations and incubation times need to be adjusted for a specific tissue to ensure diffusion of dyes and optimise emittance for detection

Development and Evaluation of a Smartphone-Based Chatbot Coach to Facilitate a Balanced Lifestyle in Individuals With Headaches (BalanceUP App): Randomized Controlled Trial

Background Primary headaches, including migraine and tension-type headaches, are widespread and have a social, physical, mental, and economic impact. Among the key components of treatment are behavior interventions such as lifestyle modification. Scalable conversational agents (CAs) have the potential to deliver behavior interventions at a low threshold. To our knowledge, there is no evidence of behavioral interventions delivered by CAs for the treatment of headaches. Objective This study has 2 aims. The first aim was to develop and test a smartphone-based coaching intervention (BalanceUP) for people experiencing frequent headaches, delivered by a CA and designed to improve mental well-being using various behavior change techniques. The second aim was to evaluate the effectiveness of BalanceUP by comparing the intervention and waitlist control groups and assess the engagement and acceptance of participants using BalanceUP. Methods In an unblinded randomized controlled trial, adults with frequent headaches were recruited on the web and in collaboration with experts and allocated to either a CA intervention (BalanceUP) or a control condition. The effects of the treatment on changes in the primary outcome of the study, that is, mental well-being (as measured by the Patient Health Questionnaire Anxiety and Depression Scale), and secondary outcomes (eg, psychosomatic symptoms, stress, headache-related self-efficacy, intention to change behavior, presenteeism and absenteeism, and pain coping) were analyzed using linear mixed models and Cohen d. Primary and secondary outcomes were self-assessed before and after the intervention, and acceptance was assessed after the intervention. Engagement was measured during the intervention using self-reports and usage data. Results A total of 198 participants (mean age 38.7, SD 12.14 y; n=172, 86.9% women) participated in the study (intervention group: n=110; waitlist control group: n=88). After the intervention, the intention-to-treat analysis revealed evidence for improved well-being (treatment: β estimate=–3.28, 95% CI –5.07 to –1.48) with moderate between-group effects (Cohen d=–0.66, 95% CI –0.99 to –0.33) in favor of the intervention group. We also found evidence of reduced somatic symptoms, perceived stress, and absenteeism and presenteeism, as well as improved headache management self-efficacy, application of behavior change techniques, and pain coping skills, with effects ranging from medium to large (Cohen d=0.43-1.05). Overall, 64.8% (118/182) of the participants used coaching as intended by engaging throughout the coaching and completing the outro. Conclusions BalanceUP was well accepted, and the results suggest that coaching delivered by a CA can be effective in reducing the burden of people who experience headaches by improving their well-being. Trial Registration German Clinical Trials Register DRKS00017422; https://trialsearch.who.int/Trial2.aspx?TrialID=DRKS0001742

Screening for Cluster Headache—Introduction of the SMARTED Scale

Patients with cluster headache often report a long diagnostic delay. This study creates and validates a screening test that could help speed up the diagnostic process. We invited patients to enrol in this diagnostic case–control study if a trigeminal autonomic headache had been suspected or confirmed. Patients in whom the diagnosis of a cluster headache was not made were controls. First, all participants answered 22 diagnostic questions with “yes” or “no”. Next, we eliminated questions that did not distinguish well between the groups. Then, the variables entered a regression model with the headache diagnosis as the dependent variable. Finally, we combined the remaining variables into a diagnostic scale and tested its accuracy. Seventy-four patients participated, 45 of whom suffered from a cluster headache. The analyses identified five questions distinguishing cluster headache patients and controls. These addressed smoking, being awakened by the pain, restlessness during the attack, unilateral tearing, and duration of the attack (hence, the “SMARTED” scale). The area under the ROC curve was 0.938; sensitivity and specificity, the positive and negative predictive values were 98%, 65%, 81% and 94%, respectively. The SMARTED scale validly and accurately screens for cluster headache in patients suspected of a trigeminal autonomic headache

Spheroid-Like Cultures for Expanding Angiopoietin Receptor-1 (aka. Tie2) Positive Cells from the Human Intervertebral Disc.

Lower back pain is a leading cause of disability worldwide. The recovery of nucleus pulposus (NP) progenitor cells (NPPCs) from the intervertebral disc (IVD) holds high promise for future cell therapy. NPPCs are positive for the angiopoietin-1 receptor (Tie2) and possess stemness capacity. However, the limited Tie2+ NPC yield has been a challenge for their use in cell-based therapy for regenerative medicine. In this study, we attempted to expand NPPCs from the whole NP cell population by spheroid-formation assay. Flow cytometry was used to quantify the percentage of NPPCs with Tie2-antibody in human primary NP cells (NPCs). Cell proliferation was assessed using the population doublings level (PDL) measurement. Synthesis and presence of extracellular matrix (ECM) from NPC spheroids were confirmed by quantitative Polymerase Chain Reaction (qPCR), immunostaining, and microscopy. Compared with monolayer, the spheroid-formation assay enriched the percentage of Tie2+ in NPCs' population from ~10% to ~36%. Moreover, the spheroid-formation assay also inhibited the proliferation of the Tie2- NPCs with nearly no PDL. After one additional passage (P) using the spheroid-formation assay, NPC spheroids presented a Tie2+ percentage even further by ~10% in the NPC population. Our study concludes that the use of a spheroid culture system could be successfully applied to the culture and expansion of tissue-specific progenitors

Investigating migraine phenotype and dynamics in women with endometriosis: an observational pilot study.

INTRODUCTION Migraine and endometriosis are chronic disabling pain conditions. There is evidence for a shared genetic background. Migraine phenotype and course in patients with the comorbidity are insufficient investigated. Both conditions can be treated with progestins. METHODS For this observational study we included women with migraine and endometriosis, visiting our clinic from 2015 to 2021. We collected available information from charts and complemented these data by a structured phone interview to collect more specific information on migraine and the course of both diseases. RESULTS From 344 patients fulfilling the inclusion criteria, 94 suffered from both, endometriosis and migraine. Migraine with aura was reported by 41% of the patients and was associated with earlier onset of migraine (age < 17 years (OR 6.54) and with a history of medication overuse headache (OR 9.9, CI 1.6-59.4). Present monthly migraine frequency (1.5 ± 2.6) was significantly lower than five years before the interview (2.9 ± 4.64). There was a correlation between medication overuse headache and use of analgesics more than 3 days/months for dysmenorrhoea (p < 0.03). ASRM endometriosis score was not associated with migraine characteristics. CONCLUSIONS We conclude that the comorbidity of endometriosis is highly linked to migraine with aura. Migraine onset in these patients was earlier. Further studies are needed to explore, if the observed decrease in migraine frequency can be attributed to recent endometriosis surgery and to understand if early diagnosis and treatment of both conditions may contribute to improve the course of both conditions. Trial registration BASEC Nr. 2021-00285