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4,177 results on '"Ramírez, José A."'

1. Differential equations in Ward's calculus

Author

Luzón, Ana, Morón, Manuel A., and Ramírez, José L.

Subjects
Mathematics - Combinatorics
Abstract

In this paper we solve some differential equations in the $D_h$ derivative in Ward's sense. We use a special metric in the formal power series ring $\K[[x]]$. The solutions of that equations are giving in terms of fixed points for certain contractive maps in our metric framework. Our main tools are Banach's Fixed Point Theorem, Fundamental Calculus Theorem and Barrow's rule for Ward's calculus. Later, we return to the usual differential calculus via Sheffer's expansion of some kind of operators. Finally, we give some examples related, in some sense, to combinatorics.

Published
2024

2. A Finite Volume scheme for the solution of discontinuous magnetic field distributions on non-orthogonal meshes

Author

Riedinger, Augusto, Saravia, Martín, and Ramírez, José

Subjects
Mathematics - Numerical Analysis
Abstract

We present a Finite Volume formulation for determining discontinuous distributions of magnetic fields within non-orthogonal and non-uniform meshes. The numerical approach is based on the discretization of the vector potential variant of the equations governing static magnetic field distribution in magnetized, permeable and current carrying media. After outlining the derivation of the magnetostatic balance equations and its associated boundary conditions, we propose a cell-centered Finite Volume framework for spatial discretization and a Block Gauss-Seidel multi-region scheme for solution. We discuss the structure of the solver, emphasizing its effectiveness and addressing stabilization and correction techniques to enhance computational robustness. We validate the accuracy and efficacy of the approach through numerical experiments and comparisons with the Finite Element method., Comment: 19 pages, 15 figures

Published
2024

3. Fibonacci--Theodorus Spiral and its properties

Author

Bacon, Michael R., Cook, Charles K., Flórez, Rigoberto, Higuita, Robinson A., Luca, Florian, and Ramírez, José L.

Subjects
Mathematics - General Mathematics
Abstract

Inspired by the ancient spiral constructed by the greek philosopher Theodorus which is based on concatenated right triangles, we have created a spiral. In this spiral, called \emph{Fibonacci--Theodorus}, the sides of the triangles have lengths corresponding to Fibonacci numbers. Towards the end of the paper, we present a generalized method applicable to second-order recurrence relations. Our exploration of the Fibonacci--Theodorus spiral aims to address a variety of questions, showcasing its unique properties and behaviors. For example, we study topics such as area, perimeter, and angles. Notably, we establish a relationship between the ratio of two consecutive areas and the golden ratio, a pattern that extends to angles sharing a common vertex. Furthermore, we present some asymptotic results. For instance, we demonstrate that the sum of the first $n$ areas comprising the spiral approaches a multiple of the sum of the initial $n$ Fibonacci numbers. Moreover, we provide a sequence of open problems related to all spiral worked in this paper. Finally, in his work Hahn, Hahn observed a potential connection between the golden ratio and the ratio of areas between spines of lengths $\sqrt{F_{n+1}}$ and $\sqrt{F_{n+2}-1}$ and the areas between spines of lengths $\sqrt{F_{n}}$ and $\sqrt{F_{n+1}-1}$ in the Theodorus spiral. However, no formal proof has been provided in his work. In this paper, we provide a proof for Hahn's conjecture., Comment: Accepted for publication by Proceedings of Fibonacci Quarterly

Published
2024

4. Counting Colored Tilings on Grids and Graphs

Author

Ramírez, José L. and Villamizar, Diego

Subjects
Computer Science - Discrete Mathematics, Mathematics - Combinatorics
Abstract

In this paper, we explore some generalizations of a counting problem related to tilings in grids of size 2xn, which was originally posed as a question on Mathematics Stack Exchange (Question 3972905). In particular, we consider this problem for the product of two graphs G and P(n), where P(n) is the path graph of n vertices. We give explicit bivariate generating functions for some specific cases., Comment: In Proceedings GASCom 2024, arXiv:2406.14588

Published
2024
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5. Flattened Catalan Words

Author

Baril, Jean-Luc, Harris, Pamela E., and Ramírez, José L.

Subjects
Mathematics - Combinatorics, 05A15, 05A19
Abstract

In this work, we define flattened Catalan words as Catalan words whose runs of weak ascents have leading terms that appear in weakly increasing order. We provide generating functions, formulas, and asymptotic expressions for the number of flattened Catalan words based on the number of runs of ascents (descents), runs of weak ascents (descents), $\ell$-valleys, valleys, symmetric valleys, $\ell$-peaks, peaks, and symmetric peaks., Comment: arXiv admin note: substantial text overlap with arXiv:2404.05672

Published
2024

6. Enumerating runs, valleys, and peaks in Catalan words

Author

Baril, Jean-Luc, Harris, Pamela E., Harry, Kimberly J., McClinton, Matt, and Ramírez, José L.

Subjects
Mathematics - Combinatorics, 05A15, 05A19
Abstract

We provide generating functions, formulas, and asymptotic expressions for the number of Catalan words based on the number of runs of ascents (descents), runs of weak ascents (descents), $\ell$-valleys, valleys, symmetric valleys, $\ell$-peaks, peaks, and symmetric peaks. We also establish some bijections with restricted Dyck paths and ordered trees that transports some statistics.

Published
2024

7. Grand zigzag knight's paths

Author

Baril, Jean-Luc, Hassler, Nathanaël, Kirgizov, Sergey, and Ramírez, José L.

Subjects
Mathematics - Combinatorics, Computer Science - Discrete Mathematics
Abstract

We study the enumeration of different classes of grand knight's paths in the plane. In particular, we focus on the subsets of zigzag knight's paths subject to constraints. These constraints include ending at ordinate 0, bounded by a horizontal line, confined within a tube, among other considerations. We present our results using generating functions or direct closed-form expressions. We derive asymptotic results, finding approximations for quantities such as the probability that a zigzag knight's path stays in some area of the plane, or for the average of the final height of such a path. Additionally, we exhibit some bijections between grand zigzag knight's paths and some pairs of compositions., Comment: 21 pages, 9 figures

Published
2024

8. The Combinatorics of Motzkin Polyominoes

Author

Baril, Jean-Luc, Kirgizov, Sergey, Ramírez, José L., and Villamizar, Diego

Subjects
Mathematics - Combinatorics, Computer Science - Discrete Mathematics
Abstract

A word $w=w_1\cdots w_n$ over the set of positive integers is a Motzkin word whenever $w_1=\texttt{1}$, $1\leq w_k\leq w_{k-1}+1$, and $w_{k-1}\neq w_{k}$ for $k=2, \dots, n$. It can be associated to a $n$-column Motzkin polyomino whose $i$-th column contains $w_i$ cells, and all columns are bottom-justified. We reveal bijective connections between Motzkin paths, restricted Catalan words, primitive \L{}ukasiewicz paths, and Motzkin polyominoes. Using the aforementioned bijections together with classical one-to-one correspondence with Dyck paths avoiding $UDU$s, we provide generating functions with respect to the length, area, semiperimeter, value of the last symbol, and number of interior points of Motzkin polyominoes. We give asymptotics and closed-form expressions for the total area, total semiperimeter, sum of the last symbol values, and total number of interior points over all Motzkin polyominoes of a given length. We also present and prove an engaging trinomial relation concerning the number of cells lying at different levels and first terms of the expanded $(1+x+x^2)^n$., Comment: 21 pages, 11 figures

Published
2024

9. Pattern Avoidance in Weak Ascent Sequences

Author

Bényi, Beáta, Mansour, Toufik, and Ramírez, José L.

Subjects
Mathematics - Combinatorics, 05A05, 05A15, 05A19
Abstract

In this paper, we study pattern avoidance in weak ascent sequences, giving some results for patterns of length 3. This is an analogous study to one given by Duncan and Steingr\'imsson (2011) for ascent sequences. More precisely, we provide systematically the generating functions for the number of weak ascent sequences avoiding the patterns $001, 011, 012, 021$, and $102$. Additionally, we establish bijective connections between pattern-avoiding weak ascent sequences and other combinatorial objects, such as compositions, upper triangular 01-matrices, and plane trees.

Published
2023
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10. Some Connections Between Restricted Dyck Paths, Polyominoes, and Non-Crossing Partitions

Author

Flórez, Rigoberto, Ramírez, José L., Velandia, Fabio A., and Villamizar, Diego

Subjects
Mathematics - Combinatorics
Abstract

A \emph{Dyck path} is a lattice path in the first quadrant of the $xy$-plane that starts at the origin, ends on the $x$-axis, and consists of the same number of North-East steps $U$ and South-East steps $D$. A \emph{valley} is a subpath of the form $DU$. A Dyck path is called \emph{restricted $d$-Dyck} if the difference between any two consecutive valleys is at least $d$ (right-hand side minus left-hand side) or if it has at most one valley. In this paper we give some connections between restricted $d$-Dyck paths and both, the non-crossing partitions of $[n]$ and some subfamilies of polyominoes. We also give generating functions to count several aspects of these combinatorial objects., Comment: This paper has been accepter for publication in Proceedings of the 52nd Southeastern International Conference on Combinatorics, Graph Theory, and Computing

Published
2023

13. Descent distribution on Catalan words avoiding ordered pairs of Relations

Author

Baril, Jean-Luc and Ramírez, José Luis

Subjects
Mathematics - Combinatorics
Abstract

This work is a continuation of some recent articles presenting enumerative results for Catalan words avoiding one or a pair of consecutive or classical patterns of length $3$. More precisely, we provide systematically the bivariate generating function for the number of Catalan words avoiding a given pair of relations with respect to the length and the number of descents. We also present several constructive bijections preserving the number of descents. As a byproduct, we deduce the generating function for the total number of descents on all Catalan words of a given length and avoiding a pair of ordered relations.

Published
2023

14. Rotation curve of the Milky Way and the mass of Sagittarius A*

Author

Ramírez, José Enrique Hernández

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

In the present work we derive an analytical expression for the mass density of an object with spherical symmetry, whose corresponding potential allows obtaining a circular velocity around it that is in agreement with the observed rotation curve of galaxies. The rotation curve of our galaxy is analyzed, determining the properties of the central object, its radius and mass whose value obtained is very close to that reported in the literature., Comment: 6 pages, 4 figures

Published
2023

15. Design and Validation of an Assessment Rubric of Relevant Competencies for Employability

Author

Sánchez-Ramírez, José Manuel, Íñigo-Mendoza, Victoria, Marcano, Beatriz, and Romero-García, Carmen

Abstract

This article highlights the importance of promoting relevant competencies for employability in vocational training students, while considering the demands of the globalized world. The objective was to design and validate an assessment rubric of relevant competencies for employability. Seven competencies were selected: problem-solving, teamwork, adaptive capacity, communication, creativity, leadership and decision-making. A rubric was designed in which three command levels were established: low, medium and high, along with their respective indicators. A content validation process was also used by means of expert judgement. Ten (10) expert judges were selected to carry out a quantitative and qualitative validation in three stages and the indicators were modified until Aiken's V coefficients of [greater than or equal to] 0.80 (p = 0.05) were obtained for all indicators of the established competencies. It is concluded that the rubric is valid enough to assess relevant competencies for employability in vocational training students.

Published
2022

16. Division and new multiplication between vectors

Author

Ramírez, José E H and Oria, E R

Subjects
Mathematics - General Mathematics, 15A03 (Primary) 11R52 (Secondary)
Abstract

The division between two vectors belonging to the same vector space is obtained by elementary procedures of vector algebra and is defined by a matrix. This representation is obtained for two and three dimensional vector spaces. A new vector multiplication is defined and an the inverse vector. Through this multiplication we can obtain the division previously defined.The meaning of vector division and multiplication are analyzed., Comment: 6 pages and 1 figure

Published
2023

17. Partial Motzkin paths with air pockets of the first kind avoiding peaks, valleys or double rises

Author

Baril, Jean-Luc and Ramírez, José Luis

Subjects
Mathematics - Combinatorics
Abstract

Motzkin paths with air pockets (MAP) of the first kind are defined as a generalization of Dyck paths with air pockets. They are lattice paths in $\mathbb{N}^2$ starting at the origin made of steps $U=(1,1)$, $D_k=(1,-k)$, $k\geq 1$ and $H=(1,0)$, where two down-steps cannot be consecutive. We enumerate MAP and their prefixes avoiding peaks (resp. valleys, resp. double rise) according to the length, the type of the last step, and the height of its end-point. We express our results using Riordan arrays. Finally, we provide constructive bijections between these paths and restricted Dyck and Motzkin paths., Comment: arXiv admin note: substantial text overlap with arXiv:2212.12404

Published
2023

18. Polyominoes and graphs built from Fibonacci words

Author

Kirgizov, Sergey and Ramírez, José Luis

Subjects
Mathematics - Combinatorics, Computer Science - Discrete Mathematics
Abstract

We introduce the $k$-bonacci polyominoes, a new family of polyominoes associated with the binary words avoiding $k$ consecutive $1$'s, also called generalized $k$-bonacci words. The polyominoes are very entrancing objects, considered in combinatorics and computer science. The study of polyominoes generates a rich source of combinatorial ideas. In this paper we study some properties of $k$-bonacci polyominoes. Specifically, we determine their recursive structure and, using this structure, we enumerate them according to their area, semiperimeter, and length of the corresponding words. We also introduce the $k$-bonacci graphs, then we obtain the generating functions for the total number of vertices and edges, the distribution of the degrees, and the total number of $k$-bonacci graphs that have a Hamiltonian cycle., Comment: 16 pages, 8 figures

Published
2022

20. Equilibrium points and their linear stability in the planar equilateral restricted four-body problem: A review and new results

Author

Ramírez, José Alejandro Zepeda and Alvarez-Ramírez, Martha

Subjects
Mathematics - Dynamical Systems, Mathematical Physics, 70F10, 37N05
Abstract

In this work, we revisit the planar restricted four-body problem to study the dynamics of an infinitesimal mass under the gravitational force produced by three heavy bodies with unequal masses, forming an equilateral triangle configuration. We unify known results about the existence and linear stability of equilibrium points of this problem which have been obtained earlier, either as relative equilibria or a central configuration of the planar restricted $(3 + 1)$-body problem. It is the first attempt in this direction. A systematic numerical investigation is performed to obtain the resonance curves in the mass space. We use these curves to answer the question about the existing boundary between the domains of linear stability and instability. The characterization of the total number of stable points found inside the stability domain is discussed.

Published
2022
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21. Knight's paths towards Catalan numbers

Author

Baril, Jean-Luc and Ramirez, José Luis

Subjects
Mathematics - Combinatorics, 05A15, 05A19
Abstract

We provide enumerating results for partial knight's paths of a given size. We prove algebraically that zigzag knight's paths of a given size ending on the $x$-axis are enumerated by the generalized Catalan numbers, and we give a constructive bijection with peakless Motzkin paths of a given length. After enumerating partial knight's paths of a given length, we prove that zigzag knight's paths of a given length ending on the $x$-axis are counted by the Catalan numbers. Finally, we give a constructive bijection with Dyck paths of a given length.

Published
2022

22. Wearable chemical sensors for biomarker discovery in the omics era

Author

Sempionatto, Juliane R, Lasalde-Ramírez, José A, Mahato, Kuldeep, Wang, Joseph, and Gao, Wei

Subjects
Analytical Chemistry, Chemical Sciences, Clinical Research, Precision Medicine, Detection, screening and diagnosis, 4.1 Discovery and preclinical testing of markers and technologies, Good Health and Well Being, Wearable Electronic Devices, Biosensing Techniques, Body Fluids, Sweat, Biomarkers, Bioanalytical chemistry, Engineering, Sensors, Techniques and instrumentation, Chemical sciences
Abstract

Biomarkers are crucial biological indicators in medical diagnostics and therapy. However, the process of biomarker discovery and validation is hindered by a lack of standardized protocols for analytical studies, storage and sample collection. Wearable chemical sensors provide a real-time, non-invasive alternative to typical laboratory blood analysis, and are an effective tool for exploring novel biomarkers in alternative body fluids, such as sweat, saliva, tears and interstitial fluid. These devices may enable remote at-home personalized health monitoring and substantially reduce the healthcare costs. This Review introduces criteria, strategies and technologies involved in biomarker discovery using wearable chemical sensors. Electrochemical and optical detection techniques are discussed, along with the materials and system-level considerations for wearable chemical sensors. Lastly, this Review describes how the large sets of temporal data collected by wearable sensors, coupled with modern data analysis approaches, would open the door for discovering new biomarkers towards precision medicine.

Published
2022

23. Avoiding a pair of patterns in multisets and compositions

Author

Jelínek, Vít, Mansour, Toufik, Ramírez, José L., and Shattuck, Mark

Subjects
Mathematics - Combinatorics, Computer Science - Discrete Mathematics, 05A05 (Primary), 05A15 (Secondary)
Abstract

In this paper, we study the Wilf-type equivalence relations among multiset permutations. We identify all multiset equivalences among pairs of patterns consisting of a pattern of length three and another pattern of length at most four. To establish our results, we make use of a variety of techniques, including Ferrers-equivalence arguments, sorting by minimal/maximal letters, analysis of active sites and direct bijections. In several cases, our arguments may be extended to prove multiset equivalences for infinite families of pattern pairs. Our results apply equally well to the Wilf-type classification of compositions, and as a consequence, we obtain a complete description of the Wilf-equivalence classes for pairs of patterns of type (3,3) and (3,4) on compositions, with the possible exception of two classes of type (3,4)., Comment: 26 pages

Published
2021
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24. New modular symmetric function and its applications: Modular $s$-Stirling numbers

Author

Abdelghafour, Bazeniar, Ahmia, Moussa, Ramírez, José L., and Villamizar, Diego

Subjects
Mathematics - Combinatorics, 05A15, 05A19
Abstract

In this paper, we consider a generalization of the Stirling number sequence of both kinds by using a specialization of a new family of symmetric functions. We give combinatorial interpretations for this symmetric functions by means of weighted lattice path and tilings. We also present some new convolutions involving the complete and elementary symmetric functions. Additionally, we introduce different families of set partitions to give combinatorial interpretations for the modular $s$-Stirling numbers., Comment: 2 figures

Published
2021

25. Restricted Dyck Paths on Valleys Sequence

Author

Flórez, Rigoberto, Mansour, Toufik, Ramírez, José L., Velandia, Fabio A., and Villamizar, Diego

Subjects
Mathematics - Combinatorics, Primary 05A15, Secondary 05A19
Abstract

In this paper we study a subfamily of a classic lattice path, the \emph{Dyck paths}, called \emph{restricted $d$-Dyck} paths, in short $d$-Dyck. A valley of a Dyck path $P$ is a local minimum of $P$; if the difference between the heights of two consecutive valleys (from left to right) is at least $d$, we say that $P$ is a restricted $d$-Dyck path. The \emph{area} of a Dyck path is the sum of the absolute values of $y$-components of all points in the path. We find the number of peaks and the area of all paths of a given length in the set of $d$-Dyck paths. We give a bivariate generating function to count the number of the $d$-Dyck paths with respect to the the semi-length and number of peaks. After that, we analyze in detail the case $d=-1$. Among other things, we give both, the generating function and a recursive relation for the total area., Comment: seven Figure and 20 pages

Published
2021

26. Risk of recurrence after discontinuing anticoagulation in patients with COVID-19- associated venous thromboembolism: a prospective multicentre cohort study

Author

Adarraga, María Dolores, Conesa, Ana Alberich, Aibar, Jesús, Lozano, Alicia Alda, Alfonso, Joaquín, Carrillo, Jesús Alonso, Amado, Cristina, García, María Angelina, Arcelus, Juan Ignacio, Ballaz, Aitor, Barba, Raquel, Hernando, María Barca, Barbagelata, Cristina, Barrón, Manuel, Andrés, Belén Barrón, Chaib, Fahd Beddar, Blanco Molina, María Ángeles, Caballero, Juan Carlos, Castellanos, Gonzalo, Chasco, Leyre, Criado, Juan, de Ancos, Cristina, Toro, Jorge del, Rodríguez, Pablo Demelo, de Juana Izquierdo, Cristina, Díaz Brasero, Ana María, Díaz Peromingo, José Antonio, Silva, Álvaro Dubois, Escribano, Juan Carlos, Falgá, Concepción, Farfán Sedano, Ana Isabel, Aracil, Cleofe Fernández, Capitán, Carmen Fernández, Jiménez, Begoña Fernández, Fernández Reyes, José Luis, Fidalgo, María Ángeles, Francisco, Iria, Gabara, Cristina, Valle, Francisco Galeano, Bragado, Francisco García, Ortega, Alberto García, Sebastián, Olga Gavín, Gil de Gómez, María Allende, Díaz, Aída Gil, Cuervo, Covadonga Gómez, Munera, Adriana González, Grau, Enric, Guirado, Leticia, Gutiérrez, Javier, Blasco, Luis Hernández, Palomares, Luis Jara, Jaras, María Jesús, Jiménez, David, Jiménez, Rafael, Jou, Inés, Joya, María Dolores, Justo, Sara Lainez, Lalueza, Antonio, Lecumberri, Ramón, León Ramírez, José Manuel, Llamas, Pilar, Lobo, José Luis, Jiménez, Luciano López, Miguel, Patricia López, López Núñez, Juan José, Ruiz, Antonio López, López Sáez, Juan Bosco, Lorenzo, Alicia, Lumbierres, Marina, Madridano, Olga, Maestre, Ana, Marchena, Pablo Javier, Marcos, María, Martín del Pozo, Mar, Martos, Francisco Martín, Maza, Jorge Manuel, Mena, Elisabeth, Mercado, Maria Isabel, Moisés, Jorge, Monreal, Manuel, Morales, María del Valle, Navas, Maria Sierra, Nieto, José Antonio, Núñez Fernández, Manuel Jesús, Olid, Mónica, Ortega, Lucía Ordieres, Ortiz, María, Osorio, Jeisson, Otálora, Sonia, Otero, Remedios, Gómez, Nazaret Pacheco, Pagán, Javier, Palomeque, Andrea Catalina, Paredes, Ezequiel, Caballero, Pedro Parra, Pedrajas, José María, Ductor, Cristina Pérez, Pinar, Montserrat Pérez, Peris, María Luisa, Pesce, María Lourdes, Porras, José Antonio, Puchades, Ramón, Cívico, Francisco Rivera, Cobo, Ana Rodríguez, Rosa, Vladimir, Brugera, Marta Romero, Artacho, Pedro Ruiz, Giménez, Nuria Ruiz, Ruiz, Justo Ruiz, Salgueiro, Georgina, Sancho, Teresa, Sendín, Vanesa, Sigüenza, Patricia, Soler, Silvia, Fernández, Susana Suárez, Tirado, Raimundo, Vilar, Ana Torrents, Torres, María Isabel, Santos, Javier Trujillo, Uresandi, Fernando, Valle, Reina, Varona, José Felipe, Villalobos, Aurora, Villares, Paula, Ay, Cihan, Nopp, Stephan, Pabinger, Ingrid, Engelen, Matthias, Vanassche, Thomas, Verhamme, Peter, Bok Yoo, Hugo Hyung, Montenegro, Ana Cristina, Morales, Silvia Natalia, Roa, Jairo, Hirmerova, Jana, Malý, Radovan, Bertoletti, Laurent, Bura-Riviere, Alessandra, Catella, Judith, Chopard, Romain, Couturaud, Francis, Espitia, Olivier, Grange, Claire, Leclercq, Barbara, Le Mao, Raphael, Mahé, Isabelle, Moustafa, Farès, Plaisance, Ludovic, Bartoli, Gabrielle Sarlon, Suchon, Pierre, Versini, Edouard, Schellong, Sebastian, Brenner, Benjamin, Dally, Najib, Tzoran, Inna, Sadeghipour, Parham, Rashidi, Fahrid, Abenante, Alessia, Barillari, Giovanni, Basaglia, Manuela, Bilora, Franca, Bissacco, Daniele, Bortoluzzi, Cristiano, Brandolin, Barbara, Casana, Renato, Ciammaichella, Maurizio, Colaizzo, Donatella, Dentali, Francesco, Di Micco, Pierpaolo, Grandone, Elvira, Imbalzano, Egidio, Deliliers, Daniela Lambertenghi, Negro, Federica, Pesavento, Raffaele, Poz, Alessandra, Prandoni, Paolo, Scarinzi, Paolo, Siniscalchi, Carmine, Taflaj, Beldisa, Tufano, Antonella, Visonà, Adriana, Hong, Ngoc Vo, Zalunardo, Beniamino, Skride, Andris, Kigitovica, Dana, Fonseca, Samuel, Marques, Rafael, Meireles, José, Pinto, Sara Barbosa, Bosevsky, Marijan, Eftimova, Aleksandra, Zdraveska, Marijan, Bounameaux, Henri, Mazzolai, Lucia, Aujayeb, Avinash, Bikdeli, Behnood, Caprini, Joseph, Weinberg, Ido, Bui, Hanh My, Jara-Palomares, Luis, Muriel, Alfonso, Demelo-Rodríguez, Pablo, López-Miguel, Patricia, López-Jiménez, Luciano, and Rivera-Cívico, Francisco

Published
2024
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32. Dung removal increases under higher dung beetle functional diversity regardless of grazing intensification

Author

Noriega, Jorge Ari, Hortal, Joaquín, deCastro-Arrazola, Indradatta, Alves-Martins, Fernanda, Ortega, Jean C. G., Bini, Luis Mauricio, Andrew, Nigel R., Arellano, Lucrecia, Beynon, Sarah, Davis, Adrian L. V., Favila, Mario E., Floate, Kevin D., Horgan, Finbarr G., Menéndez, Rosa, Milotic, Tanja, Nervo, Beatrice, Palestrini, Claudia, Rolando, Antonio, Scholtz, Clarke H., Senyüz, Yakup, Wassmer, Thomas, Ádam, Réka, Araújo, Cristina de O., Barragan-Ramírez, José Luis, Boros, Gergely, Camero-Rubio, Edgar, Cruz, Melvin, Cuesta, Eva, Damborsky, Miryam Pieri, Deschodt, Christian M., Rajan, Priyadarsanan Dharma, D’hondt, Bram, Díaz Rojas, Alfonso, Dindar, Kemal, Escobar, Federico, Espinoza, Verónica R., Ferrer-Paris, José Rafael, Gutiérrez Rojas, Pablo Enrique, Hemmings, Zac, Hernández, Benjamín, Hill, Sarah J., Hoffmann, Maurice, Jay-Robert, Pierre, Lewis, Kyle, Lewis, Megan, Lozano, Cecilia, Marín-Armijos, Diego, de Farias, Patrícia Menegaz, Murcia-Ordoñez, Betselene, Karimbumkara, Seena Narayanan, Navarrete-Heredia, José Luis, Ortega-Echeverría, Candelaria, Pablo-Cea, José D., Perrin, William, Pessoa, Marcelo Bruno, Radhakrishnan, Anu, Rahimi, Iraj, Raimundo, Amalia Teresa, Ramos, Diana Catalina, Rebolledo, Ramón E., Roggero, Angela, Sánchez-Mercado, Ada, Somay, László, Stadler, Jutta, Tahmasebi, Pejman, Triana Céspedes, José Darwin, and Santos, Ana M. C.

Published
2023
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35. Author Correction: BIM and mTOR expression levels predict outcome to erlotinib in EGFR-mutant non-small-cell lung cancer

Author

Karachaliou, Niki, Codony-Servat, Jordi, Teixidó, Cristina, Pilotto, Sara, Drozdowskyj, Ana, Codony-Servat, Carles, Giménez-Capitán, Ana, Molina-Vila, Miguel Angel, Bertrán-Alamillo, Jordi, Gervais, Radj, Massuti, Bartomeu, Morán, Teresa, Majem, Margarita, Felip, Enriqueta, Carcereny, Enric, García-Campelo, Rosario, Viteri, Santiago, González-Cao, María, Morales-Espinosa, Daniela, Verlicchi, Alberto, Crisetti, Elisabetta, Chaib, Imane, Santarpia, Mariacarmela, Luis Ramírez, José, Bosch-Barrera, Joaquim, Felipe Cardona, Andrés, de Marinis, Filippo, López-Vivanco, Guillermo, Miguel Sánchez, José, Vergnenegre, Alain, Sánchez Hernández, José Javier, Sperduti, Isabella, Bria, Emilio, and Rosell, Rafael

Published
2023
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36. Poly-Cauchy numbers -- the combinatorics behind

Author

Bényi, Beáta and Ramírez, José Luis

Subjects
Mathematics - Combinatorics, 05A05, 05A19
Abstract

We introduce poly-Cauchy permutations that are enumerated by the poly-Cauchy numbers. We provide combinatorial proofs for several identities involving poly-Cauchy numbers and some of their generalizations. The aim of this work is to demonstrate the power and beauty of the elementary combinatorial approach., Comment: 17 pages, 2 figures

Published
2021

40. Corrigendum: State of the California Current 2019–2020: Back to the Future With Marine Heatwaves?

Author

Weber, Edward D, Auth, Toby D, Baumann-Pickering, Simone, Baumgartner, Timothy R, Bjorkstedt, Eric P, Bograd, Steven J, Burke, Brian J, Cadena-Ramírez, José L, Daly, Elizabeth A, de la Cruz, Martin, Dewar, Heidi, Field, John C, Fisher, Jennifer L, Giddings, Ashlyn, Goericke, Ralf, Gomez-Ocampo, Eliana, Gomez-Valdes, Jose, Hazen, Elliott L, Hildebrand, John, Horton, Cheryl A, Jacobson, Kym C, Jacox, Michael G, Jahncke, Jaime, Kahru, Mati, Kudela, Raphe M, Lavaniegos, Bertha E, Leising, Andrew, Melin, Sharon R, Miranda-Bojorquez, Luis Erasmo, Morgan, Cheryl A, Nickels, Catherine F, Orben, Rachael A, Porquez, Jessica M, Portner, Elan J, Robertson, Roxanne R, Rudnick, Daniel L, Sakuma, Keith M, Santora, Jarrod A, Schroeder, Isaac D, Snodgrass, Owyn E, Sydeman, William J, Thompson, Andrew R, Thompson, Sarah Ann, Trickey, Jennifer S, Villegas-Mendoza, Josue, Warzybok, Pete, Watson, William, and Zeman, Samantha M

Subjects
California Current, marine heat wave, upwelling, anchovy, Ecosystem Assessment, CalCOFI, Oceanography, Ecology
Published
2022

41. On the $r$-Derangements of type B

Author

Mezo, István, Moll, Victor H., Ramírez, José L., and Villamizar, Diego

Subjects
Mathematics - Combinatorics
Abstract

Extensions of a set partition obtained by imposing bounds on the size of the parts and the coloring of some of the elements are examined. Combinatorial properties and the generating functions of some counting sequences associated with these partitions are established. Connections with Riordan arrays are presented.

Published
2021

42. Palindromic and Colored Superdiagonal Compositions

Author

Mantilla, Jazmín, Olaya-León, Wilson, and Ramírez, José L.

Subjects
Mathematics - Combinatorics, 05A15, 05A19
Abstract

A superdiagonal composition is one in which the $i$-th part or summand is of size greater than or equal to $i$. In this paper, we study the number of palindromic superdiagonal compositions and colored superdiagonal compositions. In particular, we give generating functions and explicit combinatorial formulas involving binomial coefficients and Stirling numbers of the first kind., Comment: 2 figures

Published
2021

44. Generalized Ordered Set Partitions

Author

Bényi, Beáta, Méndez, Miguel, and Ramirez, José L.

Subjects
Mathematics - Combinatorics
Abstract

In this paper, we consider ordered set partitions obtained by imposing conditions on the size of the lists, and such that the first $r$ elements are in distinct blocks, respectively. We introduce a generalization of the Lah numbers. For this new combinatorial sequence we derive its exponential generating function, some recurrence relations, and combinatorial identities. We prove and present results using combinatorial arguments, generating functions, the symbolic method and Riordan arrays. For some specific cases we provide a combinatorial interpretation for the inverse matrix of the generalized Lah numbers by means of two families of posets.

Published
2020

45. Histoplasma capsulatum Isolated from Tadarida brasiliensis Bats Captured in Mexico Form a Sister Group to North American Class 2 Clade.

Author

Vite-Garín, Tania, Estrada-Bárcenas, Daniel A, Gernandt, David S, Reyes-Montes, María Del Rocío, Sahaza, Jorge H, Canteros, Cristina E, Ramírez, José A, Rodríguez-Arellanes, Gabriela, Serra-Damasceno, Lisandra, Zancopé-Oliveira, Rosely M, Taylor, John W, and Taylor, Maria Lucia

Subjects
Histoplasma capsulatum, NAm 3 clade, bat host, concatenated sequence-types network, new lineage, phylogenetic reconstruction
Abstract

Histoplasma capsulatum is a dimorphic fungus associated with respiratory and systemic infections in mammalian hosts that have inhaled infective mycelial propagules. A phylogenetic reconstruction of this pathogen, using partial sequences of arf, H-anti, ole1, and tub1 protein-coding genes, proposed that H. capsulatum has at least 11 phylogenetic species, highlighting a clade (BAC1) comprising three H. capsulatum isolates from infected bats captured in Mexico. Here, relationships for each individual locus and the concatenated coding regions of these genes were inferred using parsimony, maximum likelihood, and Bayesian inference methods. Coalescent-based analyses, a concatenated sequence-types (CSTs) network, and nucleotide diversities were also evaluated. The results suggest that six H. capsulatum isolates from the migratory bat Tadarida brasiliensis together with one isolate from a Mormoops megalophylla bat support a NAm 3 clade, replacing the formerly reported BAC1 clade. In addition, three H. capsulatum isolates from T. brasiliensis were classified as lineages. The concatenated sequence analyses and the CSTs network validate these findings, suggesting that NAm 3 is related to the North American class 2 clade and that both clades could share a recent common ancestor. Our results provide original information on the geographic distribution, genetic diversity, and host specificity of H. capsulatum.

Published
2021

46. Contemporary use of cefazolin for MSSA infective endocarditis: analysis of a national prospective cohort

Author

Sánchez, Fernando Fernández, de Lomas, José Mª García, Rosas, Gabriel, de la Torre Lima, Javier, Bereciartua, Elena, Vidal, María José Blanco, Blanco, Roberto, Boado, María Victoria, Lázaro, Marta Campaña, Crespo, Alejandro, Carrión, Laura Guio, Del Álamo Martínez de Lagos, Mikel, Ugarte, Gorane Euba, Goikoetxea, Ane Josune, Hierro, Marta Ibarrola, Iruretagoyena, José Ramón, Zuazabal, Josu Irurzun, López-Soria, Leire, Montejo, Miguel, Nieto, Javier, Rodrigo, David, Rodríguez, Regino, Vitoria, Yolanda, Voces, Roberto, López, Mª Victoria García, Georgieva, Radka Ivanova, Ojeda, Guillermo, Bailón, Isabel Rodríguez, Morales, Josefa Ruiz, Rodríguez, Ignacio Álvarez, Galparsoro, Harkaitz Azkune, Boronat, Elisa Berritu, Odriozola, Mª Jesús Bustinduy, del Bosque Martín, Cristina, Echeverría, Tomás, Yarza, Alberto Eizaguirre, Fuentes, Ana, Goenaga, Miguel Ángel, del Río, Muskilda Goyeneche, Bauza, Ángela Granda, Iribarren, José Antonio, Urkola, Xabier Kortajarena, López, José Ignacio Pérez-Moreiras, Jiménez, Ainhoa Rengel, Reviejo, Karlos, Berbejillo, Alberto Sáez, Haza, Elou Sánchez, Alda, Rosa Sebastián, Ruiz, Itziar Solla, Ugartemendia, Irati Unamuno, Anza, Diego Vicente, Benito, Iñaki Villanueva, Arrieta, Mar Zabalo, Carrasco, Rafael, Climent, Vicente, Llamas, Patricio, Merino, Esperanza, Plazas, Joaquín, Reus, Sergio, Bouzas, Alberto, Castelo, Brais, Cuenca, José, Gutiérrez, Laura, Ramos, Lucía, Mayo, María Rodríguez, Serrano, Joaquín Manuel, Regueiro, Dolores Sousa, Martínez, Francisco Javier, del Mar Alonso, Mª, Castro, Beatriz, Melian, Teresa Delgado, Sarabia, Javier Fernández, Rosado, Dácil García, González, Julia González, Lacalzada, Juan, de la Peña, Lissete Lorenzo, Ramírez, Alina Pérez, Arrondo, Pablo Prada, Moreno, Fermín Rodríguez, Ciezar, Antonio Plata, Iglesias, José Mª Reguera, Álvarez, Víctor Asensi, Costas, Carlos, de la Hera, Jesús, Suárez, Jonnathan Fernández, Fraile, Lisardo Iglesias, Arguero, Víctor León, Menéndez, José López, Bajo, Pilar Mencia, Morales, Carlos, Torrico, Alfonso Moreno, Palomo, Carmen, Martínez, Begoña Paya, Esteban, Ángeles Rodríguez, García, Raquel Rodríguez, Asensio, Mauricio Telenti, Almela, Manuel, Ambrosioni, Juan, Azqueta, Manuel, Brunet, Mercè, Bodro, Marta, Cartañá, Ramón, Cuervo, Guillermo, Falces, Carlos, Fernández-Pittol, Mariana J, Fita, Guillermina, Fuster, David, de la Mària, Cristina García, García-Pares, Delia, Hernández-Meneses, Marta, Pérez, Jaume Llopis, Marco, Francesc, Miró, José M., Moreno, Asunción, Nicolás, David, Ninot, Salvador, Quintana, Eduardo, Paré, Carlos, Pereda, Daniel, Pericás, Juan M., Pomar, José L., Ramírez, José, Roque, Mercè, Rovira, Irene, Sandoval, Elena, Sitges, Marta, Soy, Dolors, Téllez, Adrián, Tolosana, José M., Vidal, Bárbara, Vila, Jordi, Adán, Iván, Alonso, David, Alonso, Juan Carlos, Álvarez-Uría, Ana, Bermejo, Javier, Bouza, Emilio, Caballero, Gregorio Cuerpo, Montero, Antonia Delgado, Estévez, Agustín, Ribas, Ramón Fortuny, Gargallo, Esther, Leoni, Mª Eugenia García, Mansilla, Ana González, Moraga, Francisco Javier González, Ramallo, Víctor González, Hernández, Martha Kestler, Hualde, Amaia Mari, Machado, Marina, Marín, Mercedes, Martínez-Sellés, Manuel, Melero, Rosa, Muñoz, Patricia, Monzón, Diego, Olmedo, María, Pedraz, Álvaro, Pinilla, Blanca, Pinto, Ángel, Rincón, Cristina, Rodríguez-Abella, Hugo, Rodríguez-Créixems, Marta, Sánchez-Pérez, Eduardo, Segado, Antonio, Toledo, Neera, Valerio, Maricela, Vázquez, Pilar, Moreno, Eduardo Verde, de la Villa, Sofía, Antorrena, Isabel, Loeches, Belén, Moreno, Mar, Ramírez, Ulises, Bastón, Verónica Rial, Romero, María, Rosillo, Sandra, Balbín, Jesús Agüero, Fernández, Cristina Amado, Castillo, Carlos Armiñanzas, de las Revillas, Francisco Arnaiz, Belaustegui, Manuel Cobo, Fariñas, María Carmen, Fariñas-Álvarez, Concepción, Sampedro, Marta Fernández, García, Iván, Rico, Claudia González, Gutiérrez-Fernández, Laura, Gutiérrez-Cuadra, Manuel, Díez, José Gutiérrez, Pajarón, Marcos, Parra, José Antonio, Teira, Ramón, Zarauza, Jesús, Parra, Jorge Calderón, Cobo, Marta, Domínguez, Fernando, Pavía, Pablo García, Cruz, Ana Fernández, Ramos-Martínez, Antonio, Romero, Isabel Sánchez, Centella, Tomasa, Hermida, José Manuel, Moya, José Luis, Martín-Dávila, Pilar, Navas, Enrique, Oliva, Enrique, del Río, Alejandro, Stuart, Jorge Rodríguez-Roda, Ruiz, Soledad, Tenorio, Carmen Hidalgo, Sequera, Sergio, Delia, Manuel Almendro, Araji, Omar, Barquero, José Miguel, Jambrina, Román Calvo, de Cueto, Marina, Acebal, Juan Gálvez, Méndez, Irene, Morales, Isabel, López-Cortés, Luis Eduardo, de Alarcón, Arístides, Gutiérrez-Carretero, Encarnación, Lepe, José Antonio, López-Haldón, José, Luque-Márquez, Rafael, Marín, Guillermo, Ortiz-Carrellán, Antonio, Sánchez-Domínguez, Eladio, Alonso, Luis Javier, Azcárate, Pedro, Gutiérrez, José Manuel Azcona, Blanco, José Ramón, Armas, Estíbaliz Corral, García-Álvarez, Lara, Oteo, José Antonio, Membrilla, Antonio Barros, Iglesias, Antonino Ginel, Grillo, Sara, Petracca, Rubén Leta, López-Contreras, Joaquín, Martínez, María Alba Rivera, Álvarez, M., Fernández, A.L., Martínez, Amparo, Prieto, A., Regueiro, Benito, Tijeira, E., Vega, Marino, Quiñonero, Amaia Aguirre, Miñambres, Ángela Alonso, Arana, Juan Carlos Gainzarain, de Alaiza Ortega, Sara González, Rodríguez, Miguel Ángel Morán, Rodríguez, Anai Moreno, de Zárate, Zuriñe Ortiz, Zapirain, José Joaquín Portu, de Adana Arroniz, Ester Sáez, Sánchez, Daisy Carolina Sorto, Antonio, Sánchez-Porto, Alejandro, Úbeda Iglesias, Leal, José Mª Arribas, Vázquez, Elisa García, Torres, Alicia Hernández, Blázquez, Ana, de la Morena Valenzuela, Gonzalo, Alonso, Ángel, Aramburu, Javier, Calvo, Felicitas Elena, Tarabini-Castellani, Paola, Gálvez, Eva Heredero, Bellido, Carolina Maicas, Pau, José Largo, Sepúlveda, Mª Antonia, Sierra, Pilar Toledano, Iqbal-Mirza, Sadaf Zafar, Alcolea, Eva Cascales, Yañez, Ivan Keituqwa, Martínez, Julián Navarro, Ballesta, Ana Peláez, Escobar, Eduardo Moreno, Monje, Alejandro Peña, Cabrera, Valme Sánchez, García, David Vinuesa, Asenjo, María Arrizabalaga, Luna, Carmen Cifuentes, Morcillo, Juana Núñez, Seco, Mª Cruz Pérez, Gelabert, Aroa Villoslada, Guallar, Carmen Aured, Abad, Nuria Fernández, Mangas, Pilar García, Adell, Marta Matamala, Ruiz, Mª Pilar Palacián, Porres, Juan Carlos, Vidal, Begoña Alcaraz, Del Amor Espín, María Jesús, Buendía, Francisco, Sánchez, Roberto Jiménez, Mármol, Rosario, Martínez, Francisco, Meseguer, Antonio, Pérez, Beatriz, Risco, Leticia, Saura, Zoser, Silva, Vanina, Villmarín, Mª Belén, Blanco, Mª Ángels Ribas, de Gopegui Bordes, Enrique Ruiz, Bonet, Laura Vidal, Borràs, Miquel Vives, Munera, Mª Carmen Bellón, Garaizabal, Elena Escribano, Martínez, Antonia Tercero, Luque, Juan Carlos Segura, Badía, Cristina, Palop, Lucía Boix, Xercavins, Mariona, Ibars, Sónia, Bosch, Xerach, Nebreda, Eloy Gómez, Herrera, Ibalia Horcajada, Gallego, Irene Menduiña, Pulido, Imanol, Santiago, Héctor Marrero, de Miguel Martínez, Isabel, Álamo, Elena Pisos, Sánchez, Daniel San Román, Pérez, Jorge Boan, Blanco, Eva Mª Aguilar, González, Mercedes Catalán, Peiretti, María Angélica Corres, Esteve, Andrea Eixerés, Pérez, Laura Domínguez, de Cossío Tejido, Santiago, Román, Francisco Galván, Robles, José Antonio García, Medrano, Francisco López, Gude, Mª Jesús López, Miguel, Mª Ángeles Orellana, Pilkington, Patrick, Ostalaza, Yolanda Revilla, Morales, Juan Ruiz, Solís, Sebastián Ruiz, Collado, Ana Sabín, Fernández, Marcos Sánchez, Rallo, Javier Solera, Martín, Jorge Solís, Escrihuela-Vidal, Francesc, Carratalà, Jordi, Grau, Inmaculada, Ardanuy, Carmen, Berbel, Dámaris, Salado, José Carlos Sánchez, Alegre, Oriol, Majoral, Alejandro Ruiz, Sbraga, Fabrizio, Blasco, Arnau, Sánchez, Laura Gracia, Sánchez-Rodríguez, Iván, Aldamiz, Gonzalo, Álvarez, Beatriz, Palacios, Marina Bernal, Úbeda, Alfonso Cabello, Roblas, Ricardo Fernández, Hernández, Rafael, Martín, Victoria Andrea Hortigüela, Kallmeyer, Andrea, Kancev, Cristina Landaeta, Martín, Marta, Ruiz, Miguel Morante, Lobato, Miguel Ángel Navas, Pello, Ana María, Prieto, Laura, Mallebrera, Marta Tomás, Varela, Laura, de la Peña Triguero, Mireia, Cerón, Ruth Esther Figueroa, Gómez, Lara Ruiz, Ble, Mireia, Gallego, Juan Pablo Horcajada, Ginel, Antonio José, López, Inmaculada, Mas, Alexandra, Mestres, Antoni, Molina, Lluís, Serrat, Ramón, Ribas, Núria, Sánchez, Francisca, Silverio, Ana, Suárez, Marina, Sorlí, Luisa, Recasens, Lluís, Taurón, Manuel, Regueras, María Fernández, Vallejo, María Ángeles Mantecón, Rivera, José Ángel Pérez, Mata, Nuria Sánchez, Cano, Antonia Calvo, Olivares, Miguel Fajardo, Núñez, María Victoria Millán, Sanz, Agustín Muñoz, Herrera-Hidalgo, Laura, Alonso-Menchén, David, Luque-Marquez, Rafael, Fariñas, María Del Carmen, Miró, Jose Maria, Goenaga, Miguel Angel, Angulo-Lara, Basilio, and Boix-Palop, Lucia

Published
2023
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47. Optimal prediction problems and the last zero of spectrally negative Lévy processes

Author

Pedraza Ramírez, José Manuel

Subjects
HB Economic Theory, HG Finance, QA Mathematics
Abstract

In recent years the study of Levy processes has received considerable attention in the literature. In particular, spectrally negative Levy processes have applications in insurance, finance, reliability and risk theory. For instance, in risk theory, the capital of an insurance company over time is studied. A key quantity of interest is the moment of ruin, which is classically defined as the first passage time below zero. Consider instead the situation where after the moment of ruin the company may have funds to endure a negative capital for some time. In that case, the last time below zero becomes an important quantity to be studied. An important characteristic of last passage times is that they are random times which are not stopping times. This means that the information available at any time is not enough to determine its value and only with the whole realisation of the process that it can be determined. On the other hand, stopping times are random times such that its realisation can be derived only with the past information. Suppose that at any time period there is a need to know the value of a last passage time for some appropriate actions to be taken. It is then clear that an alternative to this problem is to approximate the last passage time with a stopping time such that they are close in some sense. In this work, we consider the optimal prediction to the last zero of a spectrally negative Levy process. This is equivalent to find a stopping time that minimises its distance with respect to the last time the process goes below zero. In order to fulfil this goal, we also study the last zero before at any fixed time and its dynamics as a process. Moreover, having in mind some applications in the insurance sector, we study the joint distribution of the number of downcrossings by jump and the local time before an exponential time.

Published
2021
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49. State of the California Current 2019–2020: Back to the Future With Marine Heatwaves?

Author

Weber, Edward D, Auth, Toby D, Baumann-Pickering, Simone, Baumgartner, Timothy R, Bjorkstedt, Eric P, Bograd, Steven J, Burke, Brian J, Cadena-Ramírez, José L, Daly, Elizabeth A, de la Cruz, Martin, Dewar, Heidi, Field, John C, Fisher, Jennifer L, Giddings, Ashlyn, Goericke, Ralf, Gomez-Ocampo, Eliana, Gomez-Valdes, Jose, Hazen, Elliot L, Hildebrand, John, Horton, Cheryl A, Jacobson, Kym C, Jacox, Michael G, Jahncke, Jaime, Kahru, Mati, Kudela, Raphe M, Lavaniegos, Bertha E, Leising, Andrew, Melin, Sharon R, Miranda-Bojorquez, Luis Erasmo, Morgan, Cheryl A, Nickels, Catherine F, Orben, Rachael A, Porquez, Jessica M, Portner, Elan J, Robertson, Roxanne R, Rudnick, Daniel L, Sakuma, Keith M, Santora, Jarrod A, Schroeder, Isaac D, Snodgrass, Owyn E, Sydeman, William J, Thompson, Andrew R, Thompson, Sarah Ann, Trickey, Jennifer S, Villegas-Mendoza, Josue, Warzybok, Pete, Watson, William, and Zeman, Samantha M

Subjects
Life Below Water, California Current, marine heat wave, upwelling, anchovy, Ecosystem Assessment, CalCOFI, Oceanography, Ecology
Abstract

The California Current System (CCS) has experienced large fluctuations in environmental conditions in recent years that have dramatically affected the biological community. Here we synthesize remotely sensed, hydrographic, and biological survey data from throughout the CCS in 2019–2020 to evaluate how recent changes in environmental conditions have affected community dynamics at multiple trophic levels. A marine heatwave formed in the north Pacific in 2019 and reached the second greatest area ever recorded by the end of summer 2020. However, high atmospheric pressure in early 2020 drove relatively strong Ekman-driven coastal upwelling in the northern portion of the CCS and warm temperature anomalies remained far offshore. Upwelling and cooler temperatures in the northern CCS created relatively productive conditions in which the biomass of lipid-rich copepod species increased, adult krill size increased, and several seabird species experienced positive reproductive success. Despite these conditions, the composition of the fish community in the northern CCS remained a mixture of both warm- and cool-water-associated species. In the southern CCS, ocean temperatures remained above average for the seventh consecutive year. Abundances of juvenile fish species associated with productive conditions were relatively low, and the ichthyoplankton community was dominated by a mixture of oceanic warm-water and cosmopolitan species. Seabird species associated with warm water also occurred at greater densities than cool-water species in the southern CCS. The population of northern anchovy, which has been resurgent since 2017, continued to provide an important forage base for piscivorous fishes, offshore colonies of seabirds, and marine mammals throughout the CCS. Coastal upwelling in the north, and a longer-term trend in warming in the south, appeared to be controlling the community to a much greater extent than the marine heatwave itself.

Published
2021

50. LED control of gene expression in a nanobiosystem composed of metallic nanoparticles and a genetically modified E. coli strain

Author

Aratboni, Hossein Alishah, Rafiei, Nahid, Khorashad, Larousse Khosravi, Lerma-Escalera, Albert Isaac, Balderas-Cisneros, Francisco de Jesús, Liu, Zhaowei, Alemzadeh, Abbas, Shaji, Sadasivan, and Morones-Ramírez, José Ruben

Subjects
Biological Sciences, Industrial Biotechnology, Genetics, Nanotechnology, Bioengineering, Biotechnology, Generic health relevance, Escherichia coli, Gene Expression, Gold, Hot Temperature, Light, Luminescent Proteins, Metal Nanoparticles, Nanostructures, Particle Size, Temperature, Nanobiosystem, Gold nanoparticles, Mathematical model opto-thermal conversion, Opto-thermal nanoconverters, Metallic nanoparticles, Bioprocess production, Opto-thermal gene expression, Technology, Nanoscience & Nanotechnology, Agricultural biotechnology, Industrial biotechnology, Medical biotechnology
Abstract

BackgroundWithin the last decade, genetic engineering and synthetic biology have revolutionized society´s ability to mass-produce complex biological products within genetically-modified microorganisms containing elegantly designed genetic circuitry. However, many challenges still exist in developing bioproduction processes involving genetically modified microorganisms with complex or multiple gene circuits. These challenges include the development of external gene expression regulation methods with the following characteristics: spatial-temporal control and scalability, while inducing minimal permanent or irreversible system-wide conditions. Different stimuli have been used to control gene expression and mitigate these challenges, and they can be characterized by the effect they produce in the culture media conditions. Invasive stimuli that cause permanent, irreversible changes (pH and chemical inducers), non-invasive stimuli that cause partially reversible changes (temperature), and non-invasive stimuli that cause reversible changes in the media conditions (ultrasound, magnetic fields, and light).MethodsOpto-control of gene expression is a non-invasive external trigger that complies with most of the desired characteristics of an external control system. However, the disadvantage relies on the design of the biological photoreceptors and the necessity to design them to respond to a different wavelength for every bioprocess needed to be controlled or regulated in the microorganism. Therefore, this work proposes using biocompatible metallic nanoparticles as external controllers of gene expression, based on their ability to convert light into heat and the capacity of nanotechnology to easily design a wide array of nanostructures capable of absorbing light at different wavelengths and inducing plasmonic photothermal heating.ResultsHere, we designed a nanobiosystem that can be opto-thermally triggered using LED light. The nanobiosystem is composed of biocompatible gold nanoparticles and a genetically modified E. coli with a plasmid that allows mCherry fluorescent protein production at 37 °C in response to an RNA thermometer.ConclusionsThe LED-triggered photothermal protein production system here designed offers a new, cheaper, scalable switchable method, non-destructive for living organisms, and contribute toward the evolution of bioprocess production systems.

Published
2021

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