Measuring the Terminal Heights of Bolides to Understand the Atmospheric Flight of Large Asteroidal Fragments

The extent of penetration into the Earth's atmosphere of a meteoroid is defined by the point where its kinetic energy is no longer sufficient to produce luminosity. For most of the cases this is the point where the meteoroid disintegrates in the atmosphere due to ablation process and dynamic pressure during flight. However, some of these bodies have particular physical properties (bigger size, higher bulk strength, etc.) or favorable flight conditions (lower entry velocity or/and a convenient trajectory slope, etc.) that allow them to become a meteorite-dropper and reach the ground. In both cases, we define the end of the luminous path of the trajectory as the terminal height or end height. Thus, the end point shows the amount of deceleration till the final braking. We thus assume that the ability of a fireball to produce meteorites is directly related to its terminal height. Previous studies have discussed the likely relationship between fireball atmospheric flight properties and the terminal height. Most of these studies require the knowledge of a set of properties and physical variables which cannot be determined with sufficient accuracy from ground-based observations. The recently validated dimensionless methodology offers a new approach to this problem. All the unknowns can be reduced to only two parameters which are easily derived from observations. Despite the calculation of the analytic solution of the equations of motion is not trivial, some simplifications are admitted. Here, we describe the best performance range and the errors associated with these simplifications. We discuss how terminal heights depend on two or three variables that are easily retrieved from the recordings, provided at least three trajectory (h, v) points. Additionally, we review the importance of terminal heights, and the way they have been estimated in previous studies. Finally we discuss a new approach for calculating terminal heights.Peer reviewe

Physically based alternative to the PE criterion for meteoroids

Meteoroids impacting the Earth atmosphere are commonly classified using the PE criterion. This criterion was introduced to support the identification of the fireball type by empirically linking its orbital origin and composition characteristics. Additionally, it is used as an indicator of the meteoroid tensile strength and its ability to penetrate the atmosphere. However, the level of classification accuracy of the PE criterion depends on the ability to constrain the value of the input data, retrieved from the fireball observation, required to derive the PE value. To overcome these uncertainties and achieve a greater classification detail, we propose a new formulation using scaling laws and dimensionless variables that groups all the input variables into two parameters that are directly obtained from the fireball observations. These two parameters, alpha and beta, represent the drag and the mass-loss rates along the luminous part of the trajectory, respectively, and are linked to the shape, strength, ablation efficiency, mineralogical nature of the projectile, and duration of the fireball. Thus, the new formulation relies on a physical basis. This work shows the mathematical equivalence between the PE criterion and the logarithm of 2 alpha beta under the same PE criterion assumptions. We demonstrate that log(2 alpha beta) offers a more general formulation that does not require any preliminary constraint on the meteor flight scenario and discuss the suitability of the new formulation for expanding the classification beyond fully disintegrating fireballs to larger impactors including meteorite-dropping fireballs. The reliability of the new formulation is validated using the Prairie Network meteor observations.Peer reviewe

Multi-instrumental observations of the 2014 Ursid meteor outburst

The Ursid meteor shower is an annual shower that usually shows little activity. However, its Zenith hourly rate sometimes increases, usually either when its parent comet, 8P/Tuttle, is close to its perihelion or its aphelion. Outbursts when the comet is away from perihelion are not common and outbursts when the comet is close to aphelion are extremely rare. The most likely explanation offered to date is based on the orbital mean motion resonances. The study of the aphelion outburst of 2000 December provided a means of testing that hypothesis. A new aphelion outburst was predicted for 2014 December. The SPanish Meteor Network, in collaboration with the French Fireball Recovery and InterPlanetary Observation Network, set up a campaign to monitor this outburst and eventually retrieve orbital data that expand and confirm previous preliminary results and predictions. Despite unfavourable weather conditions over the south of Europe over the relevant time period, precise trajectories from multistation meteor data recorded over Spain were obtained, as well as orbital and radiant information for four Ursid meteors. The membership of these four meteors to the expected dust trails that were to provoke the outburst is discussed, and we characterize the origin of the outburst in the dust trail produced by the comet in the year AD 1392.Peer reviewe

Methods for epidemiological studies in competitive cycling:an extension of the IOC consensus statement on methods for recording and reporting of epidemiological data on injury and illness in sport 2020

In 2020, the IOC released a consensus statement that provides overall guidelines for the recording and reporting of epidemiological data on injury and illness in sport. Some aspects of this statement need to be further specified on a sport-by-sport basis. To extend the IOC consensus statement on methods for recording and reporting of epidemiological data on injury and illness in sports and to meet the sport-specific requirements of all cycling disciplines regulated by the Union Cycliste Internationale (UCI). A panel of 20 experts, all with experience in cycling or cycling medicine, participated in the drafting of this cycling-specific extension of the IOC consensus statement. In preparation, panel members were sent the IOC consensus statement, the first draft of this manuscript and a list of topics to be discussed. The expert panel met in July 2020 for a 1-day video conference to discuss the manuscript and specific topics. The final manuscript was developed in an iterative process involving all panel members. This paper extends the IOC consensus statement to provide cycling-specific recommendations on health problem definitions, mode of onset, injury mechanisms and circumstances, diagnosis classifications, exposure, study population characteristics and data collection methods. Recommendations apply to all UCI cycling disciplines, for both able-bodied cyclists and para-cyclists. The recommendations presented in this consensus statement will improve the consistency and accuracy of future epidemiological studies of injury and illness in cycling

Updating the Food-Based Dietary Guidelines for the Spanish Population: The Spanish Society of Community Nutrition (SENC) Proposal

Diet-related risk factors and physical inactivity are among the leading risk factors for disability and are responsible for a large proportion of the burden of chronic non-communicable diseases. Food-based dietary guidelines (FBDGs) are useful tools for nutrition policies and public health strategies to promote healthier eating and physical activity. In this paper, we discuss the process followed in developing the dietary guidelines for the Spanish population by the Spanish Society of Community Nutrition (SENC) and further explain the collaboration with primary healthcare practitioners as presented in the context of the NUTRIMAD 2018 international congress of SENC. From a health in all policies approach, SENC convened a group of experts in nutrition and public health to review the evidence on diet-health, nutrient intake and food consumption in the Spanish population, as well as food preparation, determinants and impact of diet on environmental sustainability. The collaborative group drafted the document and designed the graphic icon, which was then subject to a consultation process, discussion, and qualitative evaluation. Next, a collaborative group was established to plan a dissemination strategy, involving delegates from all the primary healthcare scientific societies in Spain. A product of this collaboration was the release of an attractive, easy-to-understand publication

Methods for epidemiological studies in competitive cycling: an extension of the IOC consensus statement on methods for recording and reporting of epidemiological data on injury and illness in sport 2020

In 2020, the IOC released a consensus statement that provides overall guidelines for the recording and reporting of epidemiological data on injury and illness in sport. Some aspects of this statement need to be further specified on a sport-by-sport basis. To extend the IOC consensus statement on methods for recording and reporting of epidemiological data on injury and illness in sports and to meet the sport-specific requirements of all cycling disciplines regulated by the Union Cycliste Internationale (UCI). A panel of 20 experts, all with experience in cycling or cycling medicine, participated in the drafting of this cycling-specific extension of the IOC consensus statement. In preparation, panel members were sent the IOC consensus statement, the first draft of this manuscript and a list of topics to be discussed. The expert panel met in July 2020 for a 1-day video conference to discuss the manuscript and specific topics. The final manuscript was developed in an iterative process involving all panel members. This paper extends the IOC consensus statement to provide cycling-specific recommendations on health problem definitions, mode of onset, injury mechanisms and circumstances, diagnosis classifications, exposure, study population characteristics and data collection methods. Recommendations apply to all UCI cycling disciplines, for both able-bodied cyclists and para-cyclists. The recommendations presented in this consensus statement will improve the consistency and accuracy of future epidemiological studies of injury and illness in cycling.http://bjsm.bmj.comhj2021Sports Medicin

Gene co-expression architecture in peripheral blood in a cohort of remitted first-episode schizophrenia patients

A better understanding of schizophrenia subtypes is necessary to stratify the patients according to clinical attributes. To explore the genomic architecture of schizophrenia symptomatology, we analyzed blood co-expression modules and their association with clinical data from patients in remission after a first episode of schizophrenia. In total, 91 participants of the 2EPS project were included. Gene expression was assessed using the Clariom S Human Array. Weighted-gene co-expression network analysis (WGCNA) was applied to identify modules of co-expressed genes and to test its correlation with global functioning, clinical symptomatology, and premorbid adjustment. Among the 25 modules identified, six modules were significantly correlated with clinical data. These modules could be clustered in two groups according to their correlation with clinical data. Hub genes in each group showing overlap with risk genes for schizophrenia were enriched in biological processes related to metabolic processes, regulation of gene expression, cellular localization and protein transport, immune processes, and neurotrophin pathways. Our results indicate that modules with significant associations with clinical data showed overlap with gene sets previously identified in differential gene-expression analysis in brain, indicating that peripheral tissues could reveal pathogenic mechanisms. Hub genes involved in these modules revealed multiple signaling pathways previously related to schizophrenia, which may represent the complex interplay in the pathological mechanisms behind the disease. These genes could represent potential targets for the development of peripheral biomarkers underlying illness traits in clinical remission stages after a first episode of schizophrenia

Verification of the Flow Regimes Based on High-fidelity Observations of Bright Meteors

Infrasound monitoring has proved to be effective in detection of meteor-generated shock waves. When combined with optical observations of meteors, this technique is also reliable for detecting centimeter-sized meteoroids that usually ablate at high altitudes, thus offering relevant clues that open the exploration of the meteoroid flight regimes. Since a shock wave is formed as a result of a passage of the meteoroid through the atmosphere, the knowledge of the physical parameters of the surrounding gas around the meteoroid surface can be used to determine the meteor flow regime. This study analyzes the flow regimes of a data set of 24 centimeter-sized meteoroids for which well-constrained infrasound and photometric information is available. This is the first time that the flow regimes for meteoroids in this size range are validated from observations. From our approach, the Knudsen and Reynolds numbers are calculated, and two different flow regime evaluation approaches are compared in order to validate the theoretical formulation. The results demonstrate that a combination of fluid dynamic dimensionless parameters is needed to allow a better inclusion of the local physical processes of the phenomena.Peer reviewe

Is SARS- CoV-2 the only cause of long-COVID?

Around 10% of adults infected with SARS-CoV-2 that survive a first episode of COVID-19 appear to experience long-term clinical manifestations. The signs and symptoms of this post-acute COVID-19 syndrome (PACS) include fatigue, dyspnea, joint pain, myalgia, chest pain, cough, anosmia, dysgeusia, headache, depression, anxiety, memory loss, concentration difficulties, and insomnia. These sequelae remind the constellation of clinical manifestations previously recognized as myalgic encephalomyelitis (ME) or chronic fatigue syndrome (CFS). This condition has been described following distinct infectious events, mostly acute viral illnesses. In this way, the pathophysiology of PACS might overlap with mechanisms involved in other post-infectious fatigue syndromes. The risk of PACS is more frequent in women than men. Additional host genetic factors could be involved. There is a dysregulation of multiple body organs and systems, involving the immune system, the coagulation cascade, endocrine organs, autonomic nervous system, microbiota–gut–brain axis, hypothalamic– pituitary–adrenal axis, hypothalamic–pituitary–thyroid axis, etc. Hypothetically, an abnormal response to certain infectious agents could trigger the development of post-infectious fatigue syndromes

Assessment of body composition and prognosis in chronic heart failure. Beyond the "obesity paradox''

Objective: It is unknown the influence of body composition in the inverse relationship of mortality with overweight and obesity in heart failure patients.Methods: 234 patients with chronic heart failure were evaluated. Body mass index, tricipital skinfold thickness, brachial muscle circumference and body fat percentage determined by bioelectrical impedance analysis were measured. The influence of previous anthropometric variables on total mortality was analyzed.Results: Mean follow-up was 21 +/- 10.7 months. We observed an inverse relationship of total mortality with body mass index (hazard ratio =0.91, 95% confidence interval, 0.87-0.96;