Plume-scale confinement on thermal convection.

Despite the ubiquity of thermal convection in nature and artificial systems, we still lack a unified formulation that integrates the system's geometry, fluid properties, and thermal forcing to characterize the transition from free to confined convective regimes. The latter is broadly relevant to understanding how convection transports energy and drives mixing across a wide range of environments, such as planetary atmospheres/oceans and hydrothermal flows through fractures, as well as engineering heatsinks and microfluidics for the control of mass and heat fluxes. Performing laboratory experiments in Hele-Shaw geometries, we find multiple transitions that are identified as remarkable shifts in flow structures and heat transport scaling, underpinning previous numerical studies. To unveil the mechanisms of the geometrically controlled transition, we focus on the smallest structure of convection, posing the following question: How free is a thermal plume in a closed system? We address this problem by proposing the degree of confinement [Formula: see text]-the ratio of the thermal plume's thickness in an unbounded domain to the lateral extent of the system-as a universal metric encapsulating all the physical parameters. Here, we characterize four convective regimes different in flow dimensionality and time dependency and demonstrate that the transitions across the regimes are well tied with [Formula: see text]. The introduced metric [Formula: see text] offers a unified characterization of convection in closed systems from the plume's standpoint.

South Atlantic explosive cyclones in 2014-2015: study employing NCEP2 and MERRA-2 reanalyses.

An analysis of explosive cyclone cases was produced by comparing the reanalysis of MERRA-2 (high spatial resolution) and NCEP2 (low spatial resolution) to South Atlantic in the 2014-2015 period. A total of 51 cases were found, of which 49 were detected by the first reanalysis and 33 by the second (2 cases identified by NCEP2 were not identified by MERRA-2). Spring was the dominant season in the formation of the cases in both reanalyses. It was observed that most systems are formed preferentially eastward of a preexisting trough at higher levels, while others are formed under an almost zonal upper airstream. This difference is more evident in the NCEP2. It was also diagnosed that the MERRA-2 shows more clearly the diffluence in the 250 hPa flow. The analysis of the composite fields revealed a negative horizontal tilt of the trough in 500 hPa, influenced by intense convection as the system develops. Besides, it pointed to a more pronounced jet stream in intense explosive cyclones and more prominent diffluence in non-intense cases. Since the NCEP2 reanalysis detected fewer cases (and only 2 intense) than MERRA-2, it was considered that the former is less suited to the analysis of this type of event.

Analysis of Vertical Misfit of Crowns Fabricated with CAD/CAM Technology using Two Scanning Techniques: Direct and Indirect.

AIM: The study evaluated the marginal vertical misfit of feldspathic ceramic crowns fabricated by the computer-aided design (CAD)/computer-aided manufacturing (CAM) technology and compared the two methods of scanning techniques: direct digital impression and indirect digital impression. MATERIALS AND METHODS: The titanium specimens were divided into two groups: scanning with the direct digital impression (DDI) at the milled prosthetic abutment level and indirect digital impression (IDI) at the cast model and after milled feldspathic ceramics blocks. Vertical marginal misfit was analyzed. The t-test was used for the analysis of the comparison factor between the groups and the one-way analysis of variance (ANOVA) test, and post hoc Tukey test was used to compare the variance of crown analysis regions within the group. A significance level of 5% was considered for the analyses. RESULTS: There was no significant difference in vertical marginal misfit between the groups of DDI and IDI (p = 0.345). In relation to each region measured within the studied groups, it was observed the similarity between the six regions analyzed in the DDI group (p >0.05) and IDI group, a significant difference between two areas. CONCLUSION: The vertical marginal adaptation was similar between digital scanning methods. Based on the data evaluated, vertical marginal adaptation indices were within acceptable clinical standards. CLINICAL SIGNIFICANCE: The direct digital scanning in unit bodies was reliable, pointing that the coating of titanium dioxide in the titanium abutment did not negatively influence the vertical marginal adaptation of the feldspathic ceramic crowns.

[How much can we trust health related information provided by mass media in Argentina?]. / ¿Cuán confiable es la información médica proporcionada por los medios de comunicación en Argentina?

To evaluate the certainty and accuracy of the healthcare information provided by the mass media in Argentina, a group of senior medical students, blind to the study objectives, identified healthcare related statements transmitted through mass media. These findings were challenged against the recommendations of a group of physicians trained in evidence-based decision making (EBDM). We compared the strength and direction of the mass media recommendations with those of experts on EBDM. Eighty one recommendations/questions were identified and answered by the experts on EBDM, 15 with high, 18 with moderate, 30 with low and 18 with very low quality of evidence. Only 53% (CI95% 42-64%) of the mass media recommendations agreed with the expert recommendation in direction (for or against) and 28% (CI95% 18-39%) were classified as inappropriate (significant discrepancies both in direction and strength). Subgroup analysis revealed that 71% (CI95% 56-86%) of there commendations made by professionals in mass media agreed with experts in direction and 17% (IC95% 6-33%) were classified as inappropriate, OR = 0.35 (CI95% 0.1-1.1) compared to recommendations in mass media by non-professionals. We conclude that the healthcare information provided by mass media in Argentina is unreliable; this fact can probably have a negative impact in the health system performance and physician-patient relationship.

[Ticagrelor in acute coronary syndrome. Explaining the inexplicable]. / Ticagrelor en el síndrome coronario agudo. Explicando lo inexplicable.

The PLATO study evaluated the efficacy of adding ticagrelor, instead of clopidogrel, to aspirin in patients with acute coronary syndrome, which showed surprisingly positive results making the drug acceptable to regulatory agencies and specialty societies worldwide. Notwithstanding the aforementioned success, contradictory information supplied by critical analysis was submitted by the sponsor. The controversial findings revealed several aspects that are difficult to explain, threatening the veracity of the study's conclusions. Mortality rate pattern, excessive benefit not comparable to prior studies, unexplained loss of follow-up development and inconsistency in findings in accordance with the country, the type of events arbitrator and monitoring committee are some of the most questionable issues. Dubious reaction to this trial is based on the fact that the information could not be found in published articles. This complex situation poses a challenge to the critical analysis of the text and raises questions as to how far the conflicts of financial interest influenced the development of the study, the communication of its results and probably, acceptance of the drug for commercial use.

[Primary epiploic appendagitis: clinical features in 73 cases]. / Apendagitis epiploica primaria. Clínica y evolución de 73 casos.

Primary epiploic appendagitis is a relatively rare disease in the differential diagnosis of acute abdomen, nonetheless it is an entity that should not be ignored by physicians and surgeons in order to prevent unnecessary interventions and overuse of antibiotics. To substantiate this concept a search was conducted at the Hospital Aleman, Buenos Aires between April 2007 and July 2013. The aim was clinical histories containing sonographic and tomographic images with diagnosis of omental appendagitis; and subsequently their electronic medical records were reviewed. The clinical features and outcome of a case series of 73 primary omental appendagitis were selected; the mean age was 45 years (± 16); 54 (74%) were men. Abdominal pain (left lower quadrant in 89% of cases) was the most common symptom. Abdominal ultrasound was performed on 44 (60%) of patients, computed tomography on 21 (29%), and both studies on 8 (11%) of cases in this series. In 49% of cases surgery consultation was requested. Fifteen patients (21%) were treated with antibiotics, 73% of them were prescribed by a clinician. Sixty seven patients (92%) were treated as outpatients with non steroidal anti-inflammatory drugs (NSAIDs); two required laparoscopic surgery, two required hospitalization and two others were treated with opioids. Epiploic apendagitis is uncommon in the differential diagnosis of acute abdomen, but is an entity that should not be ignored by physicians to prevent unnecessary interventions and overuse of antibiotics.

Severe viral lower respiratory tract infections in Brazilian children: Clinical features of a national cohort.

BACKGROUND: The accurate etiological diagnosis of lower respiratory tract infections (LRTI) is essential for their effective clinical management. The extensive use of molecular methods during the COVID-19 pandemic has enabled massive data acquisition on viral lower respiratory tract infections. The current study aims to identify clinical features associated with eight viral agents among children presenting severe LRTI. METHODS: retrospective cohort study of data from the Brazilian Influenza Epidemiological Surveillance Information System. Patients under 20 years-old who had severe LRTI with etiological confirmation through RT-PCR between 2020 and 2022 were included. Binary logistic regressions were used to examine associations between pathogens and symptoms. RESULTS: 60,657 cases were assessed. The main viral agents detected were Sars-CoV-2 (COV2) (41.2%), Respiratory Syncytial Virus (29.1%), Human Rhinovirus (HRV) (12.1%), and Influenza (FLU) (5.5%). A general mortality rate of 4.3% was observed. The multivariate analysis evidenced that COV2 less likely presented with cough (OR: 0.34; 95%CI: 0.32-0.36), respiratory discomfort (Adjusted Odds Ratio (aOR): 0.61; 95%Confidence Interval (CI): 0.59-0.64), and desaturation (aOR: 0.71; 95%CI: 0.69-0.75). RSV strongly associated with cough (aOR: 2.59; 95%CI: 2.45-2.75) and respiratory discomfort (aOR: 1.54; 95%CI: 1.46-1.62), whereas FLU was linked to fever (aOR: 2.27; 95%CI: 2.06-2.50) and sore throat (aOR: 1.48; 95%CI: 1.34-1.64). CONCLUSIONS: The viral agents responsible for severe LRTI have distinct associations with clinical features in children.

Lake surface cooling drives littoral-pelagic exchange of dissolved gases.

The extent of littoral influence on lake gas dynamics remains debated in the aquatic science community due to the lack of direct quantification of lateral gas transport. The prevalent assumption of diffusive horizontal transport in gas budgets fails to explain anomalies observed in pelagic gas concentrations. Here, we demonstrate through high-frequency measurements in a eutrophic lake that daily convective horizontal circulation generates littoral-pelagic advective gas fluxes one order of magnitude larger than typical horizontal fluxes used in gas budgets. These lateral fluxes are sufficient to redistribute gases at the basin-scale and generate concentration anomalies reported in other lakes. Our observations also contrast the hypothesis of pure, nocturnal littoral-to-pelagic exchange by showing that convective circulation transports gases such as oxygen and methane toward both the pelagic and littoral zones during the daytime. This study challenges the traditional pelagic-centered models of aquatic systems by showing that convective circulation represents a fundamental lateral transport mechanism to be integrated into gas budgets.

[Peer review, preprints and predatory journals. Publication ethics versus publicity applied to medical science]. / Revisión de pares, preprints y revistas depredadoras. ética editorial versus publicidad aplicada a la ciencia médica.

The publication of medical articles has become increasingly complex, linked to multiple factors. It poses difficult problems for both authors and journals themselves. This Editorial addresses current and controversial issues: peer review, preprints as a new way of disseminating knowledge, the growing number of publications without peer review and its variants, and the risks of predatory publications. The article proposes future guidelines as an editorial policy of MEDICINA. The controversy continues, and surely the passage of time will place our proposal in a changing scientific world like knowledge itself.

Assessment of the risk of burnout and its associated factors in healthcare professionals during the COVID-19 pandemic: A prospective cohort study.

Introduction: The COVID-19 pandemic resulted in tremendous physical and psychological pressure on healthcare professionals, especially on those working in intensive care units (ICUs) and Emergency Departments (EDs). The present study intended to characterize the profile of these professionals which is associated with burnout and determine the potential predictors of such condition. Methods: A Prospective cohort study was carried out in a tertiary hospital between March 2020 and March 2021, in Salvador, Brazil. A standardized and validated version of the Oldenburg Burnout inventory (OLBI) was applied to assess risk of burnout together with data forms designed to collect information on sociodemographic characteristics and religious beliefs. ICU and ED healthcare professionals were evaluated during off-hours at two distinct periods of the COVID-19 pandemic, in 2020 and in 2021. Differences in the results obtained from each study participant between the timepoints were compared. A binary logistic regression analysis was performed to identify the predictors of burnout development independent of other confounding factors. Results: Seventy-seven healthcare professionals with a median age of 33 (interquartile range [IQR]: 31-37.5) years and predominantly female (72.7%; n = 56) were enrolled. There were 62 professionals at risk of developing burnout through the OLBI. Those had a median age of 33 (IQR: 31-37) and female predominance (71%, n = 44). Disengagement and burnout were the only features which frequencies significantly changed over time, with increasing detection at the latest timepoint. Alcohol consumption was found to be an important risk factor for burnout development [adjusted odds ratio (aOR): 10.8 (95% CI: 1.8-64.2)]. Importantly, working in the ICU [aOR: 0.04 (95%CI: 0.01-0.32)] and the habit of praying daily [aOR: 0.07 (95%CI: 0.01-0.41)] were characteristics linked to reduced odds of burnout. Discussion: Disengagement substantially increased during the COVID-19 pandemic in healthcare professionals. Alcohol consumption favors the onset of burnout whereas habit of praying daily and working in the ICU are protective against such outcome. Institutional policies aimed at minimizing etilism may positively impact mental health of these professionals.

Expert Multinational Consensus Statement for Total Intravenous Anaesthesia (TIVA) Using the Delphi Method.

Introduction: The use of total intravenous anaesthesia (TIVA) has been well established as an anaesthetic technique over the last few decades. Significant variation in practice exists however, and volatile agents are still commonly used. This study aims to determine the motivations and barriers for using TIVA over the use of volatile agents by analysing the opinion of several international anaesthetists with specific expertise or interests. Methods and participants: The Delphi method was used to gain the opinions of expert panellists with a range of anaesthetic subspecialty expertise. Twenty-nine panellists were invited to complete three survey rounds containing statements regarding the use of TIVA. Anonymised data were captured through the software REDCap and analysed for consensus and prioritisation across statements. Starting with 12 statements, strong consensus was defined as ≥75% agreement. Stability was assessed between rounds. Results: Strong consensus was achieved for four statements regarding considerations for the use of TIVA. These statements addressed whether TIVA is useful in paediatric anaesthesia, the importance of TIVA in reducing the incidence of postoperative nausea and vomiting, its positive impact on the environment and effect on patient physiology, such as airway and haemodynamic control. Conclusions: Using the Delphi method, this international consensus showed that cost, lack of familiarity or training and the risk of delayed emergence are not considered obstacles to TIVA use. It appears, instead, that the primary motivations for its adoption are the impact of TIVA on patient experience, especially in paediatrics, and the benefit to the overall procedure outcome. The effect of TIVA on postoperative nausea and vomiting and patient physiology, as well as improving its availability in paediatrics were considered as priorities. We also identified areas where the debate remains open, generating new research questions on geographical variation and the potential impact of local availability of monitoring equipment.

Premalignant quiescent melanocytic nevi do not express the MHC class I chain-related protein A.

The MHC class I chain-related protein A (MICA) is an inducible molecule almost not expressed by normal cells but strongly up-regulated in tumor cells. MICA-expressing cells are recognized by natural killer (NK) cells, CD8+ abTCR and gdTCR T lymphocytes through the NKG2D receptor. Engagement of NKG2D by MICA triggers IFN-g secretion and cytotoxicity against malignant cells. Although most solid tumors express MICA and this molecule is a target during immune surveillance against tumors, it has been observed that high grade tumors from different histotypes express low amounts of cell surface MICA due to a metalloprotease-induced shedding. Also, melanomas develop after a complex process of neotransformation of normal melanocytes. However, the expression of MICA in premalignant stages (primary human quiescent melanocytic nevi) remains unknown. Here, we assessed expression of MICA by flow cytometry using cell suspensions from 15 primary nevi isolated from 11 patients. When collected material was abundant, cell lysates were prepared and MICA expression was also analyzed by Western blot. We observed that MICA was undetectable in the 15 primary nevi (intradermic, junction, mixed, lentigo and congenital samples) as well as in normal skin, benign lesions (seborrheic keratosis), premalignant lesions (actinic keratosis) and benign basocellular cancer. Conversely, a primary recently diagnosed melanoma showed intense cell surface MICA. We conclude that the onset of MICA expression is a tightly regulated process that occurs after melanocytes trespass the stage of malignant transformation. Thus, analysis of MICA expression in tissue sections of skin samples may constitute a useful marker to differentiate between benign and malignant nevi.

[Commercial airline routes and international distribution of COVID-19]. / Rutas aerocomerciales y distribución internacional de COVID-19.

COVID-19 has had a rapid dissemination. Departing from China, the virus has traveled all around the world. With the use of accurate mathematical models, the global spread of the disease was anticipated. Some additional information to these predictive models could be provided by the comparison of freely available maps depicting commercial air travel routes and disease spread. This analysis informs on what seems to be a direct relationship between the initially unequal worldwide distribution of the disease and the density of the commercial air traffic. This comparison may also help to identify international distributional hubs of the disease out of China. The observation of this easily accessible information may contribute to the understanding of COVID-19 spill over and help health control policies to better focus on the spread of this and other aggressively spreading respiratory infectious diseases.

La novel enfermedad COVID-19 ha tenido una rápida diseminación. Desde China, el virus viajó por todo el mundo. El potencial de la propagación global de COVID-19 fue anticipado y calculado mediante el uso de modelos matemáticos precisos. A estos modelos predictores se puede agregar información obtenida mediante la comparación de mapas gratuitos que representan la propagación internacional de la enfermedad y la densidad de las rutas aerocomerciales. Este análisis proporciona información de lo que parece ser una relación directa entre la distribución mundial inicial desigual de la enfermedad y la densidad del flujo aerocomercial. Esta comparación también puede estar sugiriendo la presencia de centros internacionales de distribución secundaria fuera de China. Con esta información de rápido acceso se puede contribuir a la mejor comprensión del derrame internacional de COVID-19 y orientar los esfuerzos de las políticas de salud para el control de esta y otras enfermedades infecciosas respiratorias agresivas.

[Treatment recommendations based on best evidences]. / Recomendaciones de tratamientos basadas en las mejores pruebas.

The fact of making recommendations about treatments demands for a systematic analysis of the different variables involved. The direction of these variables will become a recommendation into a strong one, when the benefits outweigh the harms, or into a weak one, when profits and losses are balanced. In this way, evidence based medicine analyzes this variables: 1) the quality of the literature; 2) the importance of clinical effect; 3) the magnitude of the effect; 4) the risks of the disease to treat; 5) the risks of treatment; 6) the costs; 7) the preferences of the patients; 8) the inconvenience to patients; 9) the minimum and maximum effect and 10 ) if the recommendation is strong or weak. This ten steps strategy will lead us to the construction of a scientifically based recommendation.

Influence of nutritional state on radiographic variables in upper canine teeth.

Permanent upper canine tooth impaction is related to both genetic causes and nutritional and local causes. Based on radiographic studies of children, Haavikko, 1974, calculated the median of the degree of calcification for each tooth according to age. The aim of our study was to establish associations between certain radiographic variables with respect to upper canine tooth buds and nutritional state in a population of schoolchildren. Thirty-three children of chronological ages 3 to 9 years from a population of rural schoolchildren took part in the study. The children were classified into three groups: malnourished, control and overweight. For the radiographic study we used a systematized technique using DSJ 70 kV radiographic equipment with 8 mA and Insight intraoral film (E F speed; Eastman Kodak, Rochester, NY). The images obtained from the 66 radiographic studies were scanned. The program Image tool for Windows was used to measure: (a) distance from the canine cusp to the intermaxillary suture, (b) outer angle formed between the aris of the canine tooth and the plane that cuts the intermaxillary suture perpendicularly, (c) degree of calcification (d) presence of supernumerary teeth. The values of these variables were analyzed statistically with the Kruskal-Wallis test of the SPSS program. The results were: (a) For the distance variable there is no significant difference between the malnourished and control groups (p > 0.05), although there are differences (p < 0.001) between the control and overweight groups; (b) There is no significant difference between nutritional states for the angle variable; (c) For the ratio between chronological age and dental age calculated according to degree of calcification, significant differences were found between the malnourished and overweight groups (p < 0.01), while the control group showed no difference regarding Haavikko's values (p > 0.05). Both the distance of the canine tooth bud and its degree of calcification vary in patients with nutritional disorders, therefore it would be useful to conduct a radiographic study at school age to detect tooth anomalies and reduce their consequences.

[Dual antiplatelet therapy for secondary stroke prevention in patients with acute ischemic stroke. CIERTO group recommendation]. / Doble terapia antiagregante en pacientes con accidente cerebrovascular isquémico agudo. Recomendación del grupo CIERTO.

One of the main pillars of acute ischemic stroke management is antiplatelet therapy. Different treatment schemes have been compared, suggesting that the combination of multiple antiplatelet drugs is associated with a reduced risk of stroke recurrence. However, it has also been associated with an increased risk of bleeding complications which, in the long term, surpass the mentioned benefits. However, considering that most stroke recurrences occur i n the short term, a time limited double antiplatelet scheme could result in significant benefits to patients with acute ischemic stroke. On this basis, we conducted a rapid systematic review of the literature in order to evaluate the effects of a short-term double antiplatelet therapy both on stroke recurrence and complications. All trials comparing double versus single antiplatelet therapy in patients with acute ischemic stroke were included. Results showed that double therapy reduces recurrence risk but probably marginally increases major bleeding complications. We suggest double antiplatelet therapy for the initial management of patients with minor (Score NIH < or equal to 3 or transient isquemic attack -TIA) acute ischemic stroke.

El inicio precoz del tratamiento con antiagregantes plaquetarios es considerado el estándar de cuidado para pacientes con accidente cerebrovascular isquémico agudo. Distintos esquemas de antiagregación se han comparado con resultados que sugieren que la combinación de múltiples antiagregantes se asocian a menor riesgo de recurrencia de accidente cerebrovascular (ACV) pero a expensas de un aumento en el riesgo de sangrado, lo que a largo plazo termina opacando dichos beneficos. Sin embargo, considerando que el riesgo de recurrencia de ACV es mayor en el periodo inmediato al evento, la indicación de doble tratamiento antiagregante por tiempos limitados podría asociarse a beneficios relevantes. Con este concepto, se realizó una revisión sistemática rápida con el objetivo de evaluar el efecto del tratamiento con doble antiagregación por un periodo corto intentando maximizar el beneficio y reducir al mínimo el riesgo de sangrado. Se incluyeron todos los estudios primarios identificados en los que se comparó un esquema de doble antiagregación, iniciado en el periodo agudo del evento índice (ACV o accidente isquémico transitorio - AIT), contra un esquema de simple antiagregación. El cuerpo de la evidencia mostró que la intervención (doble antiagregación) reduce el riesgo de recurrencia de ACV y probablemente se asocie a un aumento marginal en el riesgo de sangrado mayor. Sugerimos indicar doble esquema antiplaquetario para el tratamiento inicial de pacientes con ACV isquémico menor (Score NIH < o igual a 3 o AIT).