Influencia del tratamiento ácido sobre las medidas de la reflectancia de la vitrinita y la definición de la madurez termal de la materia orgánica dispersa

Mediante métodos físicos y químicos, se concentró la materia orgánica de algunas muestras con cantidades variables de calcita, silicatos y carbono orgánico total, provenientes de las Formaciones Cretácicas de ambientes marinos del Valle Superior del Magdalena – Colombia.En cuanto a la fracción orgánica, los análisis comprendieron la identificación de macerales, medidas de la reflectancia de la vitrinita y análisis por pirolisis Rock-Eval.En las rocas calcáreas de origen marino como las del Cretáceo de Colombia, las posibles vitrinitas que se encuentran en los concentrados de materia orgánica, normalmente son muy ricas en liptinitas y en la mayoría de los casos no es posible medirlas, pues dan valores más bajos de lo que normalmente son, ya que presentan alta fluorescencia. De otro lado son muy comunes los fragmentos de organismos marinos que tienen una apariencia muy similar a las vitrinitas y por lo tanto, se pueden confundir con vitrinitas reales. La diferencia, es que estas tienen unas formas definidas, presentan reflectancias bajas (menores de 0.4%) y no tienen fluorescencia.Los valores de reflectancia de la vitrinita en concentrados de materia orgánica obtenidos con el uso de ácido clorhídrico son un poco más altos que los medidos sobre concentrados de materia orgánica en los cuales no se usó dicho ácido. El tratamiento con ácido, aún en bajas concentraciones (10%), tiempos de exposición cortos (10 minutos) y temperatura (20°C), altera los componentes, dificulta su identificación y conlleva a incertidumbre acerca de las superficies en las cuales se está midiendo la reflectancia. La fluorescencia de la materia orgánica no se afecta cualitativamente lo que permitió su uso como herramienta complementaria de identificación de los macerales; sin embargo no se llevaron a cabo análisis cuantitativos de esta propiedad. AbstractThe dispersed organic matter was concentrated by physical and chemical methods in some samples with different amounts of calcite, silicates and total organic carbon from marine Cretaceous Formations of the Upper Magdalena Valley of Colombia.Regarding to the organic fraction, the analysis involved the identification of macerals, reflectance measurements and pyrolysis Rock -Eval.In calcareous marine Cretaceous rocks as those found in Colombia, possible vitrinites found in organic matter concentrates normally are very liptinites rich, then they are not suitable for vitrinite reflectance measurements or they have lower values than expected and exhibit high fluorescence. On the other hand, marine organism fragments that have a very similar appearance to vitrinites are very common, therefore can be confused with real vitrinites. The difference is that these have defined shapes, have low reflectance (less than 0.4 %) and have not fluorescence.Values of vitrinite reflectance obtained in concentrate of organic matter, using hydrochloric acid are slightly higher than those measured on organic matter concentrate without using it. Even at low concentrations (10%), short exposure times (10 minutes) and at low temperature (20°C), acid treatment (HCl), alter components, making it difficult to identify them and leads to uncertainty about surfaces in which carry out the measure of reflectance. The fluorescence of the organic matter was not qualitatively affected allowing its use as a complementary tool for identification of macerals; however quantitative analysis of this property was not carried out

Thermal history of the Northwestern Argentina, Central Andean Basin, based on first-ever reported graptolite reflectance data

The thermal maturity from the Early Paleozoic strata in Northwestern Argentina was studied using reflected light microscopy and Rock-Eval analyses. The graptolites were collected from the Acoite and Lipeón formations, at the Los Colorados section, Cordillera Oriental, and the Huaytiquina, and Muñayoc sections, Puna highland, corresponding to the “Coquena” Formation and the Cochinoca-Escaya Magmatic-Sedimentary Complex. Rock-Eval parameters were unreliable due to the low TOC, S1, and S2 values. The Cordillera Oriental region sediments have low maturity based on low reflectance (%GRo= 0.63%–1.11%) and anisotropy of graptolites. In contrast, the higher graptolite reflectance of samples from the Muñayoc and Huaytiquina sections (%GRo= 5.57%–6.62%), in the Puna region, indicates considerably higher maturity. This could result from the combination of hydrothermal fluids with a temperature range from 336 °C to 358 °C, associated volcanism, and deformation related to tectonics events, which produced a higher geothermal gradient in the Puna. The Los Colorados section's thermal maturity modeling shows a better fit considering erosion episodes at the Late Paleozoic and Early Cenozoic. However, more studies about geothermal parameters and stratigraphy are necessary to corroborate these preliminary models and propose new approaches for the Puna region.Fil: Herrera Sánchez, Nexxys Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Toro, Blanca Azucena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Ruiz Monroy, Ricardo. German Research Centre For Geosciences; AlemaniaFil: Gentzis, Thomas. Core Laboratories; Estados UnidosFil: Ocubalidet, Seare. Core Laboratories; Estados UnidosFil: Carvajal Ortiz, Humberto. Core Laboratories; Estados Unido

Analysis of the unusual earthquake of 13 August 2006 in Michoacán, México

The moderate earthquake of 13 August 2006 which occurred in the coastal area of Michoacán, México, offered the first opportunity to study an earthquake that has a focal mechanism oriented practically perpendicular to the vast majority of the earthquakes occurring along the subduction zone of the Mexican Pacific continental margin. The location and focal mechanism estimated in this study are in close agreement with those estimated by the Global Centroid Moment Tensor (CMT) project and the US Geological Survey, National Earthquake Information Center (NEIC) and place the earthquake in a complex tectonic region where 3 lithospheric plates converge. Our review shows that for the most severe historical earthquakes in the area the seismic recurrence period has expired, consequently the seismic hazard of this region is high and the analysis of the unusual event must be considered important. The main purposes of this study are (i) re-esti- mate the location and focal mechanism of the unusual event by using available seismic records close to the source, (ii) conduct a tectonic analysis of the area in relation with the previous fault plane estimated, (iii) evaluate the peak ground accelerations generated for this particular thrust event relative to those occurring during the more common events and (iv) generate the isoseismal map. The analysis of the intensities of this event together with a tectonic analysis of the area where this event occurred, attest to an unexpected behavior of this event in this region.National Autonomous University of MexicoUniversity of Colim

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires

The production of tt‾ , W+bb‾ and W+cc‾ is studied in the forward region of proton–proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fb−1 . The W bosons are reconstructed in the decays W→ℓν , where ℓ denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of $t\overline{t}$, $W+b\overline{b}$ and $W+c\overline{c}$ is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 $\pm$ 0.02 \mbox{fb}^{-1}. The $W$ bosons are reconstructed in the decays $W\rightarrow\ell\nu$, where $\ell$ denotes muon or electron, while the $b$ and $c$ quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV

Search for supersymmetry in events with one lepton and multiple jets in proton-proton collisions at root s=13 TeV

Peer reviewe

Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a $Z$ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 $< p_{\textrm{T}} < 100$ GeV and in the pseudorapidity range $2.5 < \eta < 4$. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb$^{-1}$. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages