Revistas académicas de la Universidad Católica del Norte
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On the classification of hypersurfaces in Euclidean spaces satisfying LrHr+1 = AHr+1
No full textIn this paper, we study isometrically immersed hypersurfaces of the Euclidean space En+1 satisfying the condition LrH r+i = λHr+1for an integer r ( 0 ≤ r ≤ n — 1), where Hr+i is the (r + 1)th mean curvature vector field on the hypersurface, Lr is the linearized operator of the first variation of the (r + 1) th mean curvature of hypersurface arising from its normal variations. Having assumed that on a hypersurface x : Mn → En+1, the vector field Hr+i be an eigenvector of the operator Lr with a constant real eigenvalue λ, we show that, Mn has to be an Lr-biharmonic, Lr-1-type, or Lr-null-2-type hypersurface. Furthermore, we study the above condition on a well-known family of hypersurfaces, named the weakly convex hypersurfaces (i.e. on which principal curvatures are nonnegative). We prove that, any weakly convex Euclidean hypersurface satisfying the condition Lr Hr+i = λ Hr+i for an integer r ( 0 ≤ r ≤ n — 1), has constant mean curvature of order (r + 1). As an interesting result, we have that, the Lr-biharmonicity condition on the weakly convex Euclidean hypersurfaces implies the r-minimality
Upper Edge Detour Monophonic Number of a Graph
No full textFor a connected graph G of order at least two, a path P is called a monophonic path if it is a chordless path. A longest x — y monophonic path is called an x — y detour monophonic path. A set S of vertices of G is an edge detour monophonic set of G if every edge of G lies on a detour monophonic path joining some pair of vertices in S.The edge detour monophonic number of G is the minimum cardinality of its edge detour monophonic sets and is denoted by edm(G).An edge detour monophonic set S ofG is called a minimal edge detour mono-phonic set ifno proper subset ofS is an edge detour monophonic set of G. The upper edge detour monophonic number of G, denoted by edm+(G),is defined as the maximum cardinality of a minimal edge detour monophonic set ofG. We determine bounds for it and characterize graphs which realize these bounds. For any three positive integers b, c and n with 2 ≤ b ≤ n ≤ c, there is a connected graph G with edm(G) = b, edm+(G) = c and a minimal edge detour monophonic set of cardinality n
Sufficient conditions for the boundedness and square integrability of Solutions of fourth-order differential equations
No full textSufficient conditions for the boundedness and square integrability of solutions and their derivatives of certain fourth order nonlin-ear differential equation are given by means of the Lyapunov’s second method. Our results obtained in this work, generalize existing results on fourth order nonlinear differential equations in the literature. For illustration, an example is also given
The forcing open monophonic number of a graph
No full textFor a connected graph G of order n ≥ 2, and for any mínimum open monophonic set S of G, a subset T of S is called a forcing subset for S if S is the unique minimum open monophonic set containing T. A forcing subset for S of minimum cardinality is a minimum forcing subset of S. The forcing open monophonic number of S, de-noted by fom(S), is the cardinality of a minimum forcing subset of S. The forcing open monophonic number of G, denoted by fom(G), is fom(G) = min(fom(S)), where the minimum is taken over all minimum open monophonic sets in G. The forcing open monophonic numbers of certain standard graphs are determined. It is proved that for every pair a, b of integers with 0 ≤ a ≤ b — 4 and b ≥ 5, there exists a connected graph G such that fom(G) = a and om(G) = b. It is analyzed how the addition of a pendant edge to certain standard graphs affects the forcing open monophonic number
Energy of strongly connected digraphs whose underlying graph is a cycle
No full textThe energy of a digraph is defined as E (D) =∑₁n|Re (zk)|, where z1,..., znare the eigenvalues of the adjacency matrix of D. This is a generalization of the concept of energy introduced by I. Gutman in 1978 [3]. When the characteristic polynomial of a digraph D is of the formwhere bo (D) = 1 and bk(D) ≥ 0 for all k, we show that This expression for the energy has many applications in the study of extremal values of the energy in special classes of digraphs. In this paper we consider the set D* (Cn) of all strongly connected digraphs whose underlying graph is the cycle Cn, and characterize those whose characteristic polynomial is ofthe form (0.1). As a consequence, we find the extremal values ofthe energy based on (0.2)
Diferencias en la percepción del funcionamiento familiar en adolescentes mexicanos y paraguayos
Get PDFFamily functioning is understood as a system of interactions between family members, oriented towards communication, emotional expression, and coping with problems and conflicts. These interactions determine the psychological development of the adolescent, as well as their social and academic performance. The present study focuses on a comparison between sexes on the perception of family functioning among early and middle-stage adolescents from both Paraguay and Mexico. The sample is constituted by 1728 adolescents aged between 13 and 18 years old (Mage=15; DS=1.460). All adolescents attend to public middle schools, 767 of them to schools in Asunción (Mage=15.20; DS=1.336) and 961 of them to schools in Mexico City (Mage=14.84; DS=1.534). The instrument used to measure the variables was the Escala de Relaciones Intrafamiliares (Rivera-Heredia & Andrade, 2010); Intrafamilial Relationships Scale, by its name in English. The data was analyzed by the software SPSS v.21, running a multivariate analysis of variance (MANOVA). There were found significant differences by country and age, with interaction of both variables in all familial functioning’ scales. There were no significant differences by sex in any of the scales. The results indicate that low scores in the scale among Paraguayan adolescents may be due to cultural factors.El funcionamiento familiar se conceptualiza como las relaciones entre los integrantes de una familia, enfocadas en la comunicación, la expresión emocional y la solución de problemas y conflictos. Estas relaciones son determinantes para el desarrollo psicológico del adolescente y su desempeño a nivel académico y social. Se realiza una comparación de la percepción del funcionamiento familiar, por sexo, de adolescentes tempranos y medios de Paraguay y México. La muestra está constituida por 1728 adolescentes de entre 13 y 18 años (Medad=15; DE=1.460). Todos los participantes son estudiantes en escuelas públicas de enseñanza escolar básica y media, 767 asisten a escuelas de la ciudad de Asunción (Medad=15.20; DE=1.336) y 961 cursan en escuelas de la Ciudad de México (Medad=14.84; DE=1.534). Se aplicó Cédula Sociodemográfica para el Adolescente y su Familia (Barcelata, 2013) y la Escala de Relaciones Intrafamiliares (Rivera-Heredia & Andrade, 2010). El análisis de varianza multivariado (MANOVA) ejecutado con el software SPSS v.21, hallo diferencias significativas por país, y por edad, observándose una interacción de ambas variables en todas las escalas del instrumento. No se encontró diferencias significativas por sexo. Los bajos índices de funcionamiento familiar en la muestra paraguaya podrían deberse a factores socio-culturales
Eficacia de un programa de empoderamiento en la capacidad de autocuidado de la salud en adultos mayores mexicanos jubilados
Get PDFINTRODUCTION: Changes in health conditions of older adults is a process affected by issues such as economy, politics, culture,demography, technology, biology, society, and education among others, as well as institutional programs focused on containment and control risk factors of different morbidities. OBJECTIVE: To analyze the impact and efficacy of an empowerment program in retired older adults’ self-care ability. METHOD: The sample was composed of 250 retired Mexican older adults from Hidalgo with an age rank of 69 and access to health services. Seven tests were applied: Barthel Index, TINETTI Test, Folstein’s MMSE, the Yesavage Test, Older Adult’s Ability and Perception of Self-Care Test, Mini Nutritional Assessment Scale, and a self-report of the Health Empowerment Scale. Self-care perception, functional independence, falling risk, cognitive state, depression symptoms,nutritional status, and empowerment for self-care were compared at the beginning and at the end of the program. RESULTS: Meaningful differences (p < 0.05) in functional, depressive, and nutritional states were observed. Falling risk decreased whereas cognitive state remained unchanged. Self-care ability perception and empowerment also showed substantial differences. CONCLUSIONS: These findings show that appropriate training and empowerment of self-care actions may impact the quality of life positively.INTRODUCCION: La modificación en las condiciones de salud de los adultos mayores, es un proceso multifactorial y dinámico en el que influyen aspectos económicos, políticos, culturales, demográficos, tecnológicos, biológicos, sociales y educativos, además de los programas institucionales enfocados en la contención y control de los factores de riesgo de las distintas morbilidades. OBJETIVO: El objetivo de este estudio fue analizar el impacto y eficacia de un programa de empoderamiento en la capacidad de autocuidado y condiciones de salud en adultos mayores. METODO: participaron 250 adultos mayores jubilados de la ciudad de Hidalgo México, con un promedio de edad de 69 años, con acceso a servicios de salud. Estos fueron evaluados con el Test de Capacidad y Percepción de Autocuidado del Adulto Mayor, Índice de Barthel, Test de TINETTI, Mini-mental State Examination de Folstein, Test de Yesavage, Escala Mini Nutricional, Autorreporte de la Escala de Empoderamiento de Salud. Se comparó la percepción de autocuidado, independencia funcional, riesgo de sufrir caídas, estado cognitivo, síntomas depresivos, estado nutricional y empoderamiento para el cuidado a la salud al inicio y al final del programa. RESULTADOS. Se observaron diferencias significativas (p < 0.05) en los estados funcional, depresivo, nutricional y se disminuyó el riesgo de sufrir caídas, mientras que el estado cognitivo no presentó modificación. La percepción de la capacidad de autocuidado y empoderamiento también presentó diferencias significativas. CONCLUSIONES. Los hallazgos presentados demuestran que la capacitación adecuada y el empoderamiento de las acciones de autocuidado, pueden impactar en el mejoramiento de la calidad de vida. 
Weak forms of continuity and openness
No full textSome new class of functions, called somewhat δ-precontinuous, somewhat δ-preopen and hardly δ-preopen functions, have been defined and studied by utilizing δ-preopen sets. Moreover, characterizations and properties of these functions are presented
Matrix transformation on statistically convergent sequence spaces of interval number sequences
No full textThe main purpose of this paper is to introduce the necessary and sufficient conditions for the matrix of interval numbers Ā = (ānk) such that Ā-transform of x = (xk) belongs to the sets c0S(i) ∩ ℓi∞, cS(i) ∩ ℓi∞, where in particular x ∈ c0S(i) ∩ ℓi∞ and x ∈ cS(i) ∩ ℓi∞ respectively
On linear maps that preserve G-partial-isometries in Hilbert space
No full textLet Ti be a complex Hilbert space and B(TT) the algebra of all bounded linear operators on H. We give the concrete forms of surjec-tive continue unital linear maps from B(TT) onto itself that preserves G-partial-isometric operators