218 research outputs found
Global Continua of Positive Equilibria for some Quasilinear Parabolic Equation with a Nonlocal Initial Condition
This paper is concerned with a quaslinear parabolic equation including a
nonlinear nonlocal initial condition. The problem arises as equilibrium
equation in population dynamics with nonlinear diffusion. We make use of global
bifurcation theory to prove existence of an unbounded continuum of positive
solutions
Probabilistic representation for solutions of an irregular porous media type equation: the degenerate case
We consider a possibly degenerate porous media type equation over all of
with , with monotone discontinuous coefficients with linear
growth and prove a probabilistic representation of its solution in terms of an
associated microscopic diffusion. This equation is motivated by some singular
behaviour arising in complex self-organized critical systems. The main idea
consists in approximating the equation by equations with monotone
non-degenerate coefficients and deriving some new analytical properties of the
solution
On the upstream mobility scheme for two-phase flow in porous media
When neglecting capillarity, two-phase incompressible flow in porous media is
modelled as a scalar nonlinear hyperbolic conservation law. A change in the
rock type results in a change of the flux function. Discretizing in
one-dimensional with a finite volume method, we investigate two numerical
fluxes, an extension of the Godunov flux and the upstream mobility flux, the
latter being widely used in hydrogeology and petroleum engineering. Then, in
the case of a changing rock type, one can give examples when the upstream
mobility flux does not give the right answer.Comment: A preprint to be published in Computational Geoscience
Steady states in a structured epidemic model with Wentzell boundary condition
We introduce a nonlinear structured population model with diffusion in the
state space. Individuals are structured with respect to a continuous variable
which represents a pathogen load. The class of uninfected individuals
constitutes a special compartment that carries mass, hence the model is
equipped with generalized Wentzell (or dynamic) boundary conditions. Our model
is intended to describe the spread of infection of a vertically transmitted
disease, for example Wolbachia in a mosquito population. Therefore the
(infinite dimensional) nonlinearity arises in the recruitment term. First we
establish global existence of solutions and the Principle of Linearised
Stability for our model. Then, in our main result, we formulate simple
conditions, which guarantee the existence of non-trivial steady states of the
model. Our method utilizes an operator theoretic framework combined with a
fixed point approach. Finally, in the last section we establish a sufficient
condition for the local asymptotic stability of the positive steady state
Effects of a refugee elective on medical student perceptions
<p>Abstract</p> <p>Background</p> <p>There are growing numbers of refugees throughout the world. Refugee health is a relatively unstudied and rarely taught component of medical education. In response to this need, a Refugee Health Elective was begun. Medical student perceptions toward cultural aspects of medicine and refugee health before and after participation in the elective were measured.</p> <p>Methods</p> <p>Preliminary questionnaires were given to all preclinical students at the academic year commencement with follow-up questionnaires at the refugee elective's conclusion. Both questionnaires examined students' comfort in interacting with patients and familiarity with refugee medical issues, alternative medical practices, and social hindrances to medical care. The preliminary answers served as a control and follow-up questionnaire data were separated into participant/non-participant categories. All preclinical medical students at two Midwestern medical schools were provided the opportunity to participate in the Refugee Health Elective and surveys. The 3 data groups were compared using unadjusted and adjusted analysis techniques with the Kruskall-Wallis, Bonferroni and ANCOVA adjustment. P-values < 0.05 were considered significant.</p> <p>Results</p> <p>408 and 403 students filled out the preliminary and follow-up questionnaires, respectfully, 42 of whom participated in the elective. Students considering themselves minorities or multilingual were more likely to participate. Elective participants were more likely to be able to recognize the medical/mental health issues common to refugees, to feel comfortable interacting with foreign-born patients, and to identify cultural differences in understanding medical/mental health conditions, after adjusting for minority or multilingual status.</p> <p>Conclusion</p> <p>As medical schools integrate a more multicultural curriculum, a Refugee Health Elective for preclinical students can enhance awareness and promote change in attitude toward medical/mental health issues common to refugees. This elective format offers tangible and effective avenues for these topics to be addressed.</p
Caracterización de pacientes con mielopatía espondilótica cervical intervenidos por disectomía anterior
Introduction: cervical spondylotic myelopathy is a common disease, which accounts for a quarter of all upper-limb paresthesia. Anterior graft discectomy is one of the most widely used surgical techniques in the world to treat this disease.Objective: to characterize patients with cervical spondylotic myelopathy who underwent surgery using the anterior discectomy with graft technique.Methods: a retrospective, descriptive, longitudinal study was conducted in 35 patients with cervical spondylotic myelopathy who underwent surgery using the anterior graft discectomy technique at “Lucia Iñiguez Landín” Clinical Surgical Teaching Hospital from January 2017 to December 2019. The variables studied were: age, sex, race, personal pathological history, signs and symptoms (before the surgery), cervical level affected, sequelae and complications.Results: male patients predominated (59,9 %), with ages between 45 and 60 years (45,71 %) and with personal pathological history of obesity (40 %). The prevailing clinical manifestations before surgery were hyperreflexia (65,71 %) and paresthesia (62,85 %). The most affected cervical segment was C5-C7 (91,42 %). The main complications were generalized hyperreflexia (17,14 %) and pain (8,57 %).Conclusions: patients with cervical spondylotic myelopathy surgically treated by the anterior discectomy with graft technique were mostly male, in ages after the fourth decade of life. Patients presented hyperreflexia before the surgery, and could develop generalized hyperreflexia as a complication.Introducción: la mielopatía espondilótica cervical es una enfermedad frecuente, que representa la cuarta parte de las parestesias en miembros superiores. La disectomía anterior con injerto es una de las técnicas quirúrgicas más utilizadas en el mundo para tratar esta enfermedad.Objetivo: Caracterizar los pacientes con mielopatía espondilótica cervical intervenidos quirúrgicamente por la técnica disectomía anterior con injerto.Método: Se realizó un estudio observacional, descriptivo, longitudinal retrospectivo en 35 pacientes con mielopatía espondilótica cervical intervenidos quirúrgicamente por la técnica de disectomía anterior con injerto en el Hospital Clínico Quirúrgico Docente “Lucia Iñiguez Landín” en el período de enero del 2017 a diciembre del 2019. Las variables estudiadas fueron: edad, sexo, color de piel, antecedentes patológicos personales, signos y síntomas (antes de la operación), nivel cervical afectado, secuelas y complicaciones.Resultados: Se encontró predominio de pacientes masculinos (59,9 %), con edades entre 45 y 60 años (45,71 %) y con antecedentes patológicos personales de obesidad (40 %). Las manifestaciones clínicas que predominaron antes de la intervención quirúrgica fueron la hiperreflexia (65,71 %) y la parestesia (62,85 %). El segmento cervical más afectado fue C5-C7 (91,42 %). Las principales complicaciones fueron la hiperreflexia generalizada (17,14 %) y el dolor (8,57).Conclusiones: los pacientes con mielopatía espondilótica cervical intervenidos quirúrgicamente por la técnica disectomía anterior con injerto fueron de sexo masculino en su mayoría, con edades pasadas de la cuarta década de vida. Los pacientes presentaron hiperreflexia antes de la operación, pudiendo desarrollar hiperreflexia generalizada como complicación
Cluster randomised controlled trial of a peer-led lifestyle intervention program: study protocol for the Kerala diabetes prevention program.
BACKGROUND: India currently has more than 60 million people with Type 2 Diabetes Mellitus (T2DM) and this is predicted to increase by nearly two-thirds by 2030. While management of those with T2DM is important, preventing or delaying the onset of the disease, especially in those individuals at 'high risk' of developing T2DM, is urgently needed, particularly in resource-constrained settings. This paper describes the protocol for a cluster randomised controlled trial of a peer-led lifestyle intervention program to prevent diabetes in Kerala, India. METHODS/DESIGN: A total of 60 polling booths are randomised to the intervention arm or control arm in rural Kerala, India. Data collection is conducted in two steps. Step 1 (Home screening): Participants aged 30-60 years are administered a screening questionnaire. Those having no history of T2DM and other chronic illnesses with an Indian Diabetes Risk Score value of ≥60 are invited to attend a mobile clinic (Step 2). At the mobile clinic, participants complete questionnaires, undergo physical measurements, and provide blood samples for biochemical analysis. Participants identified with T2DM at Step 2 are excluded from further study participation. Participants in the control arm are provided with a health education booklet containing information on symptoms, complications, and risk factors of T2DM with the recommended levels for primary prevention. Participants in the intervention arm receive: (1) eleven peer-led small group sessions to motivate, guide and support in planning, initiation and maintenance of lifestyle changes; (2) two diabetes prevention education sessions led by experts to raise awareness on T2DM risk factors, prevention and management; (3) a participant handbook containing information primarily on peer support and its role in assisting with lifestyle modification; (4) a participant workbook to guide self-monitoring of lifestyle behaviours, goal setting and goal review; (5) the health education booklet that is given to the control arm. Follow-up assessments are conducted at 12 and 24 months. The primary outcome is incidence of T2DM. Secondary outcomes include behavioural, psychosocial, clinical, and biochemical measures. An economic evaluation is planned. DISCUSSION: Results from this trial will contribute to improved policy and practice regarding lifestyle intervention programs to prevent diabetes in India and other resource-constrained settings. TRIAL REGISTRATION: Australia and New Zealand Clinical Trials Registry: ACTRN12611000262909
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