METEORITOS Y ASTROBLEMAS DE LA PATAGONIA ARGENTINA

Todos hemos escuchado hablar de meteoritos, o visto sus devastadores impactos en películas de ficción. Pero, ¿qué son?, ¿cómo se producen y de dónde provienen? ¿Con qué frecuencia llegan a nuestro planeta? ¿Impactan o han impactado alguna vez en nuestra región? Los meteoritos son trozos de asteroides que vagan por el espacio recorriendo órbitas propias. Buena parte de ellos proviene del cinturón de asteroides que hay entre Marte y Júpiter. Este artículo ofrece un recorrido por los posibles cráteres de impacto meteorítico y una guía de los meteoritos hallados en su territorio

Effects of alirocumab on types of myocardial infarction: insights from the ODYSSEY OUTCOMES trial

Aims  The third Universal Definition of Myocardial Infarction (MI) Task Force classified MIs into five types: Type 1, spontaneous; Type 2, related to oxygen supply/demand imbalance; Type 3, fatal without ascertainment of cardiac biomarkers; Type 4, related to percutaneous coronary intervention; and Type 5, related to coronary artery bypass surgery. Low-density lipoprotein cholesterol (LDL-C) reduction with statins and proprotein convertase subtilisin–kexin Type 9 (PCSK9) inhibitors reduces risk of MI, but less is known about effects on types of MI. ODYSSEY OUTCOMES compared the PCSK9 inhibitor alirocumab with placebo in 18 924 patients with recent acute coronary syndrome (ACS) and elevated LDL-C (≥1.8 mmol/L) despite intensive statin therapy. In a pre-specified analysis, we assessed the effects of alirocumab on types of MI. Methods and results  Median follow-up was 2.8 years. Myocardial infarction types were prospectively adjudicated and classified. Of 1860 total MIs, 1223 (65.8%) were adjudicated as Type 1, 386 (20.8%) as Type 2, and 244 (13.1%) as Type 4. Few events were Type 3 (n = 2) or Type 5 (n = 5). Alirocumab reduced first MIs [hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.77–0.95; P = 0.003], with reductions in both Type 1 (HR 0.87, 95% CI 0.77–0.99; P = 0.032) and Type 2 (0.77, 0.61–0.97; P = 0.025), but not Type 4 MI. Conclusion  After ACS, alirocumab added to intensive statin therapy favourably impacted on Type 1 and 2 MIs. The data indicate for the first time that a lipid-lowering therapy can attenuate the risk of Type 2 MI. Low-density lipoprotein cholesterol reduction below levels achievable with statins is an effective preventive strategy for both MI types.For complete list of authors see http://dx.doi.org/10.1093/eurheartj/ehz299</p

Effect of alirocumab on mortality after acute coronary syndromes. An analysis of the ODYSSEY OUTCOMES randomized clinical trial

Background: Previous trials of PCSK9 (proprotein convertase subtilisin-kexin type 9) inhibitors demonstrated reductions in major adverse cardiovascular events, but not death. We assessed the effects of alirocumab on death after index acute coronary syndrome. Methods: ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab) was a double-blind, randomized comparison of alirocumab or placebo in 18 924 patients who had an ACS 1 to 12 months previously and elevated atherogenic lipoproteins despite intensive statin therapy. Alirocumab dose was blindly titrated to target achieved low-density lipoprotein cholesterol (LDL-C) between 25 and 50 mg/dL. We examined the effects of treatment on all-cause death and its components, cardiovascular and noncardiovascular death, with log-rank testing. Joint semiparametric models tested associations between nonfatal cardiovascular events and cardiovascular or noncardiovascular death. Results: Median follow-up was 2.8 years. Death occurred in 334 (3.5%) and 392 (4.1%) patients, respectively, in the alirocumab and placebo groups (hazard ratio [HR], 0.85; 95% CI, 0.73 to 0.98; P=0.03, nominal P value). This resulted from nonsignificantly fewer cardiovascular (240 [2.5%] vs 271 [2.9%]; HR, 0.88; 95% CI, 0.74 to 1.05; P=0.15) and noncardiovascular (94 [1.0%] vs 121 [1.3%]; HR, 0.77; 95% CI, 0.59 to 1.01; P=0.06) deaths with alirocumab. In a prespecified analysis of 8242 patients eligible for ≥3 years follow-up, alirocumab reduced death (HR, 0.78; 95% CI, 0.65 to 0.94; P=0.01). Patients with nonfatal cardiovascular events were at increased risk for cardiovascular and noncardiovascular deaths (P<0.0001 for the associations). Alirocumab reduced total nonfatal cardiovascular events (P<0.001) and thereby may have attenuated the number of cardiovascular and noncardiovascular deaths. A post hoc analysis found that, compared to patients with lower LDL-C, patients with baseline LDL-C ≥100 mg/dL (2.59 mmol/L) had a greater absolute risk of death and a larger mortality benefit from alirocumab (HR, 0.71; 95% CI, 0.56 to 0.90; Pinteraction=0.007). In the alirocumab group, all-cause death declined wit h achieved LDL-C at 4 months of treatment, to a level of approximately 30 mg/dL (adjusted P=0.017 for linear trend). Conclusions: Alirocumab added to intensive statin therapy has the potential to reduce death after acute coronary syndrome, particularly if treatment is maintained for ≥3 years, if baseline LDL-C is ≥100 mg/dL, or if achieved LDL-C is low. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01663402

Modelado de las estructuras de los cráteres en Paraguay: II- Región Este

We report here the discovery and study of several new modeled large impact craters in Eastern Paraguay, South America. They were studied by geophysical information (gravimetry, magnetism), field geology and also by microscopic petrography. Clear evidences of shock metamorphic effects were found (e.g., diaplectic glasses, PF, PDF in quartz and feldspar) at 4 of the modeled craters: 1) Negla: diameter:~80-81 km., 2) Yasuka Renda D:~96 km., 3) Tapyta, D: ~80 km. and 4) San Miguel, D: 130-136 km. 5) Curuguaty, D: ~110 km. was detected and studied only by geophysical information. Target-rocks range goes from the crystalline Archaic basement to Permian sediments. The modeled craters were in some cases cut by tholeiitic/alkaline rocks of Mesozoic age and partially covered by lavas of the basaltic Mesozoic flows (Negla, Yasuka Renda, Tapyta andCuruguaty). One of them was covered in part by sediments of Grupo Caacupé (age: Silurian/Devonian). Some of these modeled craters show gold, diamonds, uranium and REE mineral deposits associated. All new modeled large impact craters are partially to markedly eroded.Este trabajo representa los avances en la tarea de levantar información sobre el fenómeno de impacto meteorítico en el Paraguay Oriental. Se realiza una apreciación corta y preliminar, basada en la geofísica (gravimetría, magnetometría y espesor cortical) acompañada de alguna información sobre la geología (de superficie) y petrografía microscópica que evidencian metamorfismo de impacto (PFs, PDFs, vidrio diapléctico) en cuatro cráteres de impacto meteorítico: Negla con ~80-81 km-D., Yasuka Renda con ~96 km-D., Tapyta con ~80 km-D. y San Miguel con ~130-136 km-D. Donde un quinto, Curuguaty con ~110 km-D. fue reconocido con base a la información geofísica -probable cráter de impacto meteorítico. Las unidades impactadas varian desde el basamento cristalino Arcaico/Proterozoico Inf.-Sup. a sedimentos del Pérmico. Los modelados cráteres de impacto meteoritico son cortados por diques de rocas toleíticas y/o alcalinas del Mesozoico, cubiertos por lavas toleíticas del Mesozoico (Negla, Yasuka Renda, Tapyta y Curuguaty) y uno de ellos fue cubierto (en parte) por sedimentos del Grupo Caacupé (Siluro/Devónico). En las cinco estructuras mencionadas se delata la presencia de mineralizaciones o indicios de la presencia de mineralizaciones como oro, diamantes, REE. Cráteres de impacto meteorítico modelados que están parcial a marcadamente erosionados.Fil: Presser, Jaime L. B.. Universidad Nacional de Asunción; ParaguayFil: Fariña Dolsa, Sandra. Universidad Nacional de Asunción; ParaguayFil: Larroza Cristaldo, Fernando A.. Universidad Nacional de Asunción; ParaguayFil: Rocca, Maximiliano. Gobierno de la Ciudad de Buenos Aires. Secretaria de Cultura; ArgentinaFil: Alonso, Ricardo Narciso. Universidad Nacional de Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto Superior de Correlación Geológica. Grupo Vinculado al INSUGEO- Centro de Estudios Geologicos Andinos; ArgentinaFil: Acevedo, Rogelio Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Cabral Antúnez, Nestor D.. Universidad Nacional de Asunción; ParaguayFil: Baller, Lindomar. Universidade Federal do Paraná; BrasilFil: Zarza Lima, Pedro R.. Universidad Nacional de Asunción; ParaguayFil: Sekatcheff, Jean M.. Universidad Nacional de Asunción; Paragua