Publications by authors named "Fabiano Ribeiro"

27 Publications

  • Page 1 of 1

On the relation between transversal and longitudinal scaling in cities.

PLoS One 2020 19;15(5):e0233003. Epub 2020 May 19.

Department of Mathematics, City University of London, London, United Kingdom.

Does the scaling relationship between population sizes of cities with urban metrics like economic output and infrastructure (transversal scaling) mirror the evolution of individual cities in time (longitudinal scaling)? The answer to this question has important policy implications, but the lack of suitable data has so far hindered rigorous empirical tests. In this paper, we advance the debate by looking at the evolution of two urban variables, GDP and water network length, for over 5500 cities in Brazil. We find that longitudinal scaling exponents are city-specific. However, they are distributed around an average value that approaches the transversal scaling exponent provided that the data is decomposed to eliminate external factors, and only for cities with a sufficiently high growth rate. We also introduce a mathematical framework that connects the microscopic level to global behaviour, finding good agreement between theoretical predictions and empirical evidence in all analyzed cases. Our results add complexity to the idea that the longitudinal dynamics is a micro-scaling version of the transversal dynamics of the entire urban system. The longitudinal analysis can reveal differences in scaling behavior related to population size and nature of urban variables. Our approach also makes room for the role of external factors such as public policies and development, and opens up new possibilities in the research of the effects of scaling and contextual factors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0233003PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7236989PMC
August 2020

Anatomy of the Scapula Applied to the Posterior Surgical Approach: Safety Parameters during Access to the Lateral Angle.

Rev Bras Ortop (Sao Paulo) 2019 Sep 29;54(5):587-590. Epub 2019 Oct 29.

Grupo de Ombro e Cotovelo, Hospital do Servidor Público Estadual de São Paulo, São Paulo, SP, Brasil.

 The objective of this paper was to identify safety parameters in the posterior surgical approach of the scapula through a cross-sectional cadaver study.  Thirteen cadaver shoulders with no history of surgery or prior musculoskeletal dysfunction, with mean age, weight, and height of 70.1 years, 61.5 kg, and 1.64 m, respectively, were dissected. The anatomic landmark of the studied pathway (infraglenoid tubercle) and its distance to the axillary and suprascapular nerves were measured.  The mean distance between the infraglenoid tubercle (IT) and the axillary nerve (AN) was 23.8 mm, and the mean distance from the IT to the suprascapular nerve (SN) was 33.2 mm.  The posterior approach may be considered safe through the interval between the infraspinatus and teres minor. However, caution should be taken during muscle spacing because of the short distance between the fracture site and the location of the SN and AN. These precautions help to avoid major postoperative complications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.rbo.2017.12.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6855917PMC
September 2019

PROXIMAL HUMERUS FRACTURE WITH LOCKING PLATE: FUNCTIONAL AND RADIOGRAPHIC RESULTS.

Acta Ortop Bras 2019 May-Jun;27(3):164-168

Shoulder and Elbow Group, Orthopedics and Traumatology Service, Hospital do Servidor Público Estadual de São Paulo (SOT/HSPE), São Paulo, SP, Brazil.

Objective: To correlate the functional outcome and radiographic indices of proximal humerus fractures treated with locking plate.

Methods: Seventy patients with proximal humerus fractures treated with locking plate, with mean follow-up of 30 months. These patients were analyzed for the score of the University of California, Los Angeles (UCLA) for the operated shoulder, range of motion measurements and radiography of both shoulders. After that, a graphical correlation was established between the radiographic measurements and the functional outcomes.

Results: 78% good and excellent results according to the UCLA score, with mean130° elevation; 45° lateral rotation; and thumb-T10 medial rotation. The type of fracture according to the Neer classification and age had a significant correlation with the range of motion. An association was found between the lowest mean elevation and the UCLA score when the neck-shaft angle variation in the antero-posterior plane was greater than 15° varus (p <0.001).

Conclusion: The variation of the neck-shaft angle measurement in the anteroposterior plane showed significant correlation with the range of motion and can be one of the predictors of functional results in proximal humerus fractures treated with locking plate.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1590/1413-785220192703142049DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6699399PMC
August 2019

Cities, from Information to Interaction.

Entropy (Basel) 2018 Oct 31;20(11). Epub 2018 Oct 31.

Department of Forest Science, Universidade de São Paulo, Avenida Pádua Dias 11, Piracicaba, São Paulo 13418-900, Brazil.

From physics to the social sciences, information is now seen as a fundamental component of reality. However, a form of information seems still underestimated, perhaps precisely because it is so pervasive that we take it for granted: the information encoded in the very environment we live in. We still do not fully understand how information takes the form of cities, and how our minds deal with it in order to learn about the world, make daily decisions, and take part in the complex system of interactions we create as we live together. This paper addresses three related problems that need to be solved if we are to understand the role of environmental information: (1) the problem: how can we preserve information in the built environment? (2) The problem: how do we make environmental information meaningful? and (3) the problem: how do we use environmental information in our daily lives? Attempting to devise a solution to these problems, we introduce a three-layered model of information in cities, namely environmental information in physical space, environmental information in semantic space, and the information enacted by interacting agents. We propose forms of estimating entropy in these different layers, and apply these measures to emblematic urban cases and simulated scenarios. Our results suggest that ordered spatial structures and diverse land use patterns encode information, and that aspects of physical and semantic information affect coordination in interaction systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/e20110834DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7512396PMC
October 2018

Evolution of urban scaling: Evidence from Brazil.

PLoS One 2018 4;13(10):e0204574. Epub 2018 Oct 4.

Department of Civil and Environmental Engineering, Swiss Federal Institute of Technology Lausanne, Lausanne, VD, Switzerland.

During the last years, the new science of cities has been established as a fertile quantitative approach to systematically understand the urban phenomena. One of its main pillars is the proposition that urban systems display universal scaling behavior regarding socioeconomic, infrastructural and individual basic services variables. This paper discusses the extension of the universality proposition by testing it against a broad range of urban metrics in a developing country urban system. We present an exploration of the scaling exponents for over 60 variables for the Brazilian urban system. Estimating those exponents is challenging from the technical point of view because the Brazilian municipalities' definition follows local political criteria and does not regard characteristics of the landscape, density, and basic utilities. As Brazilian municipalities can deviate significantly from urban settlements, urban-like municipalities were selected based on a systematic density cut-off procedure and the scaling exponents were estimated for this new subset of municipalities. To validate our findings we compared the results for overlaying variables with other studies based on alternative methods. It was found that the analyzed socioeconomic variables follow a superlinear scaling relationship with the population size, and most of the infrastructure and individual basic services variables follow expected sublinear and linear scaling, respectively. However, some infrastructural and individual basic services variables deviated from their expected regimes, challenging the universality hypothesis of urban scaling. We propose that these deviations are a product of top-down decisions/policies. Our analysis spreads over a time-range of 10 years, what is not enough to draw conclusive observations, nevertheless we found hints that the scaling exponent of these variables are evolving towards the expected scaling regime, indicating that the deviations might be temporally constrained and that the urban systems might eventually reach the expected scaling regime.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0204574PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6171854PMC
March 2019

Disorders of the long head of the biceps: tenotomy tenodesis.

Rev Bras Ortop 2017 May-Jun;52(3):291-297. Epub 2017 Apr 28.

Hospital do Servidor Público Estadual de São Paulo, Departamento de Ortopedia, São Paulo, SP, Brazil.

Disorders of the long head of biceps tendon are common in clinical practice. Their causes could be degenerative, inflammatory, instability (subluxation or luxation) or traumatic. They are generally associated to other diseases of the shoulder, mainly rotator cuff injuries. Currently, there is controversy in the literature regarding the indications for surgical treatment and the choice of the best technique for each case, due to the possibility of esthetic deformity, loss of muscle strength, and residual pain. The objective of this study was to identify the indications for surgical treatment, the best surgical technique, and the advantages and disadvantages of each technique described in the orthopedic literature for the treatment of long head of biceps tendon injuries. A revision of the orthopedic medical literature on the following databases: Biblioteca Regional de Medicina (BIREME), Medline, PubMed, Cochrane Library and Google Scholar, comprising articles published in the period from 1991 to 2015.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.rboe.2017.04.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5497000PMC
April 2017

Fractal dimension and universality in avascular tumor growth.

Phys Rev E 2017 Apr 20;95(4-1):042406. Epub 2017 Apr 20.

Departamento de Física, Universidade Federal de Lavras, 37200-000 Lavras, MG, Brazil.

For years, the comprehension of the tumor growth process has been intriguing scientists. New research has been constantly required to better understand the complexity of this phenomenon. In this paper, we propose a mathematical model that describes the properties, already known empirically, of avascular tumor growth. We present, from an individual-level (microscopic) framework, an explanation of some phenomenological (macroscopic) aspects of tumors, such as their spatial form and the way they develop. Our approach is based on competitive interaction between the cells. This simple rule makes the model able to reproduce evidence observed in real tumors, such as exponential growth in their early stage followed by power-law growth. The model also reproduces (i) the fractal-space distribution of tumor cells and (ii) the universal growth behavior observed in both animals and tumors. Our analyses suggest that the universal similarity between tumor and animal growth comes from the fact that both can be described by the same dynamic equation-the Bertalanffy-Richards model-even if they do not necessarily share the same biological properties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevE.95.042406DOI Listing
April 2017

A model of urban scaling laws based on distance dependent interactions.

R Soc Open Sci 2017 Mar 22;4(3):160926. Epub 2017 Mar 22.

EACH-Universidade de São Paulo (USP) , Av. Arlindo Bettio, 1000 (Vila Guaraciaba), 03828-000 São Paulo, SP, Brazil.

Socio-economic related properties of a city grow faster than a linear relationship with the population, in a log-log plot, the so-called . Conversely, the larger a city, the more efficient it is in the use of its infrastructure, leading to a on these variables. In this work, we addressed a simple explanation for those scaling laws in cities based on the interaction range between the citizens and on the fractal properties of the cities. To this purpose, we introduced a measure of social potential which captured the influence of social interaction on the economic performance and the benefits of amenities in the case of infrastructure offered by the city. We assumed that the population density depends on the fractal dimension and on the distance-dependent interactions between individuals. The model suggests that when the city interacts as a whole, and not just as a set of isolated parts, there is improvement of the socio-economic indicators. Moreover, the bigger the interaction range between citizens and amenities, the bigger the improvement of the socio-economic indicators and the lower the infrastructure costs of the city. We addressed how public policies could take advantage of these properties to improve cities development, minimizing negative effects. Furthermore, the model predicts that the sum of the scaling exponents of social-economic and infrastructure variables are 2, as observed in the literature. Simulations with an agent-based model are confronted with the theoretical approach and they are compatible with the empirical evidences.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1098/rsos.160926DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5383838PMC
March 2017

Safety zone for posterosuperior shoulder access: study on cadavers.

Rev Bras Ortop 2016 Jul-Aug;51(4):449-53. Epub 2016 Jun 8.

Hospital do Servidor Público Estadual de São Paulo, São Paulo, SP, Brazil.

Objective: The posterosuperior shoulder access used in surgical treatment for acromioclavicular dislocation was constructed through dissection of 20 shoulders from 10 recently chilled adult cadavers, and the distances from this route to the nearby neurovascular structures were analyzed.

Methods: A Kirschner wire was introduced into the top of the base of the coracoid process through the posterosuperior shoulder access, in the area of the origin of the conoid and trapezoid ligaments, thus reproducing the path for inserting two anchors for anatomical reconstruction of the coracoclavicular ligaments. The smallest distance from the insertion point of the Kirschner wire to the suprascapular nerve and artery/vein was measured.

Results: The mean distance from the suprascapular nerve to the origin of the coracoclavicular ligaments at the top of the base of the coracoid process was 18.10 mm (range: 13.77-22.80) in the right shoulder and 18.19 mm (range: 12.59-23.75) in the left shoulder. The mean distance from the suprascapular artery/vein to the origin of the coracoclavicular ligaments was 13.10 mm (range: 9.28-15.44) in the right shoulder and 14.11 mm (range: 8.83-18.89) in the left shoulder. Comparison between the contralateral sides did not show any statistical difference.

Conclusion: The posterosuperior shoulder access route for anatomical reconstruction of the coracoclavicular ligaments in treating acromioclavicular dislocation should be performed respecting the minimum limit of 8.83 mm medially.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.rboe.2016.06.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4974107PMC
August 2016

Treatment of proximal humeral fractures using anatomical locking plate: correlation of functional and radiographic results.

Rev Bras Ortop 2016 May-Jun;51(3):261-7. Epub 2016 Apr 19.

Service of Orthopedic and Traumatology, Hospital do Servidor Público Estadual de São Paulo (SOT/HSPE), Sao Paulo, SP, Brazil.

Objective: To correlate the functional outcomes and radiographic indices of proximal humerus fractures treated using an anatomical locking plate for the proximal humerus.

Methods: Thirty-nine patients with fractures of the proximal humerus who had been treated using an anatomical locking plate were assessed after a mean follow-up of 27 months. These patients were assessed using the University of California Los Angeles (UCLA) score and their range of motion was evaluated using the method of the American Academy of Orthopedic Surgeons on the operated shoulder and comparative radiographs on both shoulders. The correlation between radiographic measurements and functional outcomes was established.

Results: We found that 64% of the results were good or excellent, according to the UCLA score, with the following means: elevation of 124°; lateral rotation of 44°; and medial rotation of thumb to T9. The type of fracture according to Neer's classification and the patient's age had significant correlations with the range of motion, such that the greater the number of parts in the fracture and the greater the patient's age were, the worse the results also were. Elevation and UCLA score were found to present associations with the anatomical neck-shaft angle in anteroposterior view; fractures fixed with varus deviations greater than 15° showed the worst results (p < 0.001).

Conclusion: The variation in the neck-shaft angle measurements in anteroposterior view showed a significant correlation with the range of motion; varus deviations greater than 15° were not well tolerated. This parameter may be one of the predictors of functional results from proximal humerus fractures treated using a locking plate.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.rboe.2015.08.018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4887510PMC
June 2016

Impacted valgus fractures of the proximal humerus.

Rev Bras Ortop 2016 Mar-Apr;51(2):127-31. Epub 2016 Feb 2.

Hospital do Servidor Público Estadual de São Paulo, São Paulo, SP, Brazil.

Impacted valgus fractures of the proximal humerus are considered to be a special type fracture, since impaction of the humeral head on the metaphysis with maintenance of the posteromedial periosteum improves the prognosis regarding occurrences of avascular necrosis. This characteristic can also facilitate the reduction maneuver and increase the consolidation rate of these fractures, even in more complex cases. The studies included were obtained by searching the Bireme, Medline, PubMed, Cochrane Library and Google Scholar databases for those published between 1991 and 2013. The objective of this study was to identify the most common definitions, classifications and treatment methods used for these fractures in the orthopedic medical literature.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.rboe.2016.01.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4811991PMC
April 2016

Measurement of the tendon of the biceps brachii after tenotomy: study on cadavers.

Rev Bras Ortop 2015 Jul-Aug;50(4):445-9. Epub 2015 Jul 3.

Hospital do Servidor Público Estadual de São Paulo, São Paulo, SP, Brazil.

Objective: To evaluate the influence of elbow and forearm range of motion on the distal excursion of the long head of the biceps (LHB).

Methods: The distal excursion of the LHB after tenotomy of the shoulders of eight cadavers was ascertained by measuring the distance between a point marked out on the LHB, 3 cm from the anterolateral border of the acromion, and its position at different degrees of elbow flexion, using a digital pachymeter. The measurements at elbow flexion of 135°, 90°, 45° and 0° were noted: these angles were established using a goniometer. The measurements were made with the forearm in neutral, supination and pronation positions.

Results: Differences between the mean measurements of the distal excursion of the LHB (total sample) were observed between the degrees of elbow flexion (p < 0.01). However, no statistical differences were observed between the different forearm positions, between the sides, genders and ages of the cadavers studied.

Conclusion: Progressive extension of the elbow caused progressive distal excursion of the LHB, but without interference in the forearm position, gender, side or age of the cadavers studied.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.rboe.2015.06.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4563048PMC
September 2015

Models for Allee effect based on physical principles.

J Theor Biol 2015 Nov 5;385:143-52. Epub 2015 Sep 5.

USP - Universidade de São Paulo, FFCLRP - Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Departamento de Física e Matemática, Av Bandeirantes 3900, CEP: 14040-901 Ribeirão Preto, São Paulo, Brazil. Electronic address:

We propose some models of single species with Allee effect based on physical principles. A method is used to obtain the expression for the per capita growth rate (a macroscopic information) starting from the characteristics of interactions between the individuals (a microscopic information). We assume that the agents in a model of a single species interact according to the distance between them. Moreover these agents must (i) cooperate with their nearest neighbors, (ii) compete with neighbors at an intermediate distance, and (iii) being indifferent to those who are far away. Using these assumptions and based on fundamental physical principles, we find what appears to be a new way of establishing models of single species with Allee effect.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jtbi.2015.08.018DOI Listing
November 2015

Low-term results from non-conventional partial arthroplasty for treating rotator cuff arthroplasthy.

Rev Bras Ortop 2015 May-Jun;50(3):324-30. Epub 2015 Apr 23.

Orthopedics and Traumatology Service, Hospital do Servidor Público Estadual de São Paulo, São Paulo, SP, Brazil.

Objective: To evaluate the evolution of the functional results from CTA(®) hemiarthroplasty for surgically treating degenerative arthroplathy of the rotator cuff, with a mean follow-up of 5.4 years.

Methods: Eighteen patients who underwent CTA(®) partial arthroplasty to treat degenerative arthroplathy of the rotator cuff between April 2007 and June 2009 were reevaluated, with minimum and mean follow-ups of 4.6 years and 5.4 years, respectively. Pre and postoperative parameters for functionality and patient satisfaction were used (functional scale of the University of California in Los Angeles, UCLA). All the patients underwent prior conservative treatment for 6 months and underwent surgical treatment because of the absence of satisfactory results. Patients were excluded if they presented any of the following: previous shoulder surgery; pseudoparalysis; insufficiency of the coracoacromial arch (type 2 B in Seebauer's classification); neurological lesions; or insufficiency of the deltoid muscle and the subscapularis muscle.

Results: With a mean follow-up of 5.4 years, 14 patients considered that they were satisfied with the surgery (78%); the mean range of joint motion for active elevation improved from 55.8° before the operation to 82.0° after the operation; the mean external rotation improved from 18.9° before the operation to 27.3° after the operation; and the mean medial rotation remained at the level of the third lumbar vertebra. The mean UCLA score after the mean follow-up of 5.4 years was 23.94 and this was an improvement in comparison with the preoperative mean and the mean 1 year after the operation.

Conclusion: The functional results from CTA(®) hemiarthroplasty for treating rotator cuff arthroplasty in selected patients remained satisfactory after a mean follow-up of 5.4 years.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.rboe.2015.04.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4519650PMC
August 2015

Safety zone for surgical access in the middle third of the clavicle: study on cadavers.

Rev Bras Ortop 2015 May-Jun;50(3):270-3. Epub 2015 Jun 17.

Hospital do Servidor Público Estadual de São Paulo, São Paulo, SP, Brazil.

Objective: The aim of this study was to establish a neurovascular safety zone for surgical access in the middle third of the clavicle, by means of dissection on cadavers.

Methods: Twenty shoulders were dissected in 10 cadavers, with deep dissection of the middle third of the clavicle. The following structures were identified: subclavian vein, upper trunk of the brachial plexus (anterior and posterior divisions) and suprascapular nerve. These structures were marked out in order to measure their distances from the most proximal point of the middle third of the clavicle.

Results: The mean distances from the middle third of the clavicle to the suprascapular nerve, subclavian vein, upper trunk, anterior division of the upper trunk and posterior division of the upper trunk were respectively, for the right side: 15.92 cm, 10.77 cm, 23.68 cm, 14.60 cm and 15.42 cm; and for the left side: 12.69 cm; 9.82 cm; 22.19 cm; 12.16 cm and 13.46 cm.

Conclusion: There was a statistical difference in the distances to the suprascapular nerve and anterior division of the upper trunk, in comparing between the right and left sides. The closest neurovascular structures to the middle third of the clavicle were the suprascapular nerve and subclavian vein.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.rboe.2015.06.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4519670PMC
August 2015

Acromioclavicular dislocation: postoperative evaluation of the coracoclavicular ligaments using magnetic resonance.

Rev Bras Ortop 2015 Mar-Apr;50(2):195-9. Epub 2015 Apr 24.

Hospital do Servidor Público Estadual Francisco Morato de Oliveira, São Paulo, SP, Brazil.

Objective: To radiologically evaluate the healing of the coracoclavicular ligaments after surgical treatment for acromioclavicular dislocation.

Methods: Ten patients who had undergone surgical treatment for acromioclavicular dislocation via a posterosuperior route at least one year earlier were invited to return for radiological assessment using magnetic resonance. This evaluation was done by means of analogy with the scale described in the literature for studying the healing of the anterior cruciate ligament of the knee and for measuring the healed coracoclavicular ligaments.

Results: A scar structure of fibrous appearance had formed in 100% of the cases. In 50% of the cases, the images of this structure had a good appearance, while the other 50% were deficient.

Conclusion: Late postoperative evaluation using magnetic resonance, on patients who had been treated for acute acromioclavicular dislocation using a posterosuperior route in the shoulder, showed that the coracoclavicular ligaments had healed in 100% of the cases, but that this healing was deficient in 50%.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.rboe.2015.04.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4519617PMC
August 2015

A non-phenomenological model of competition and cooperation to explain population growth behaviors.

Bull Math Biol 2015 Mar 28;77(3):409-33. Epub 2015 Feb 28.

Departamento de Física (DFI), Universidade Federal de Lavras (UFLA), Caixa Postal 3037, Lavras, Minas Gerais, 37200-000, Brazil,

This paper is an extension of a previous work which proposes a non-phenomenological model of population growth that is based on the interactions among the individuals of a population. In addition to what had already been studied—that the individuals interact competitively—in the present work it is also considered that the individuals interact cooperatively. As a consequence of this new consideration, a richer dynamics is observed. For instance, besides getting the population models already reached from the original version of the model (as the Malthus, Verhulst, Gompertz, Richards, Bertalanffy and power-law growth models), the new formulation also reaches the von Foerster growth model and also a regime of divergence of the population at a finite time. An agent-based model is also presented in order to give support to the analytical results. Moreover, this new approach of the model explains the Allee effect as an emergent behavior of the cooperative and competitive interactions among the individuals. The Allee effect is the characteristic of some populations of increasing the population growth rate in a small-sized population. Whereas the models presented in the literature explain the Allee effect with phenomenological ideas, the model presented here explains this effect by the interactions between the individuals. The model is tested with empirical data to justify its formulation. Another interesting macroscopic emergent behavior from the model proposed is the observation of a regime of population divergence at a finite time. It is interesting that this characteristic is observed in humanity's global population growth. It is shown that in a regime of cooperation, the model fits very well to the human population growth data from 1000 AD to nowadays.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11538-014-0059-zDOI Listing
March 2015

Richards-like two species population dynamics model.

Theory Biosci 2014 Dec 13;133(3-4):135-43. Epub 2014 Aug 13.

Departamento de Ciências Exatas (DEX), Universidade Federal de Lavras (UFLA), Caixa Postal 3037, Lavras, Minas Gerais, Brazil,

The two-species population dynamics model is the simplest paradigm of inter- and intra-species interaction. Here, we present a generalized Lotka-Volterra model with intraspecific competition, which retrieves as particular cases, some well-known models. The generalization parameter is related to the species habitat dimensionality and their interaction range. Contrary to standard models, the species coupling parameters are general, not restricted to non-negative values. Therefore, they may represent different ecological regimes, which are derived from the asymptotic solution stability analysis and are represented in a phase diagram. In this diagram, we have identified a forbidden region in the mutualism regime, and a survival/extinction transition with dependence on initial conditions for the competition regime. Also, we shed light on two types of predation and competition: weak, if there are species coexistence, or strong, if at least one species is extinguished.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12064-014-0205-zDOI Listing
December 2014

Anatomical parameters in the lateral ulnar collateral ligament reconstruction: a cadaver study.

Rev Bras Ortop 2013 Jan-Feb;48(1):52-56. Epub 2013 Jun 11.

MSc in Medicine/Orthopedics. Attending Physician in the Shoulder and Elbow Group, Orthopedics and Traumatology Service, State of São Public Servants' Hospital (HSPE), São Paulo, SP, Brazil.

Introduction: The purpose of this study was to indentify the ulnar insertion of the LUCL using the olecranon tip and the radial head as parameters to guide the ligament reconstruction surgery.

Methods: Thirteen elbows of eight fresh cadavers were dissected for the study of the LUCL. The distances between the proximal and distal insertion of the LUCL (footprint), between the radial head and the footprint and between the olecranon tip and the footprint were measure with a digital pachimeter.

Results: The average distance from the radial head to the proximal and distal ulnar insertion of the LUCL was 13.6 and 22.99 mm, respectively. The average distance between the olecranon tip and the proximal and distal ulnar insertion of the LUCL was 38.25 and 47.6 respectively. The mean length of the LUCL footprint was 9.35 mm.

Conclusions: The LUCL insertion has a wide footprint with average 9.3 mm (7.5-11 mm). Ulnar insertion half point be located at 18.2 mm of the radial head and at 42.9 mm of olecranon tip.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.rboe.2012.05.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6565991PMC
June 2013

POSTEROSUPERIOR SURGICAL ACCESS ROUTE FOR TREATMENT OF ACROMIOCLAVICULAR DISLOCATIONS: RESULTS FROM 84 SURGICAL CASES.

Rev Bras Ortop 2012 Sep-Oct;47(5):563-7. Epub 2015 Nov 4.

Trainee Physician, specializing in Shoulder and Elbow Surgery at the Orthopedics and Traumatology Clinic, Public Servants' Hospital of the State of São Paulo (HSPE), São Paulo, SP, Brazil.

Objective: To evaluate the results from surgical treatment of 84 cases of acute acromioclavicular dislocation, using a posterosuperior access route.

Methods: Eighty-four cases of acute acromioclavicular dislocation (grade III in the Allman-Tossy classification) operated between November 2002 and May 2010 were evaluated. The patients' mean age was 34 years. The diagnoses were made using clinical and radiographic evaluations. The patients were operated by the same surgical team, within three weeks of the date of the trauma, using a posterosuperior approach to the shoulder to access the top of the base of the coracoid process for placement of two anchors, which were used in reducing the dislocation. The minimum follow-up was 12 months. The postoperative clinical-radiographic evaluation was done using the modified Karlsson criteria and the University of California at Los Angeles (UCLA) score.

Results: 92.8% of the 84 patients treated presented good or excellent results, and 7.2% presented fair or poor results, using the UCLA assessment score. According to the modified Karlsson criteria, 76.2% were assessed as grade A, 17.9% as grade B and 5.9% as grade C.

Conclusion: The posterosuperior access route to the shoulder is a new option for accessing the coracoid process and treating acromioclavicular dislocation, with clinical and radiographic results equivalent to those in the literature.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S2255-4971(15)30004-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4799449PMC
April 2016

RESULTS OF SURGICAL TREATMENT OF DENERATIVE ARTHROPATHY OF THE ROTATOR CUFF USING HEMIARTHROPLASTY- CTA(®).

Rev Bras Ortop 2012 Jan-Feb;47(1):66-72. Epub 2015 Nov 16.

Intern of the Shoulder Group of the Orthopedics and Traumatology Service, HSPE - IAMSPE - São Paulo, SP, Brazil.

Objective: To assess results of CTA(®) partial shoulder arthroplasty for treatment of degenerative arthropathy of the rotator cuff.

Methods: Between December 2006 and June 2009, 23 shoulders of 23 patients were submitted to CTA(®) type partial shoulder arthroplasty for treatment of arthropathy secondary to rotator cuff injury. Post-operative follow up time ranged from 6 to 35 months. Mean age was 74.1 years. Patients were predominantly female, representing 78.3% of cases. The right limb was affected in 18 patients. All patients had undergone at least 6 months of physiotherapy without improvement of the algetic picture, and being submitted to surgery by the same surgical team. None of the patients had history of surgery on the affected shoulder. The method elected for assessing patients during post-operative follow up was based on UCLA scoring criteria.

Results: Improvement in pain was observed in all patients after arthroplasty. Mean UCLA pain score was 9.22 (ranging from 10 to 8). Mean function was 6 (10 to 2). Active frontal flexion was 2.39 (highest score 4 and lowest 0). Mean frontal flexion force was 4.09, maximum was 5 and minimum 3. Mean score on the UCLA was 26.52. 95% were satisfied with the surgery.

Conclusion: CTA(®) type partial shoulder arthroplasty produced satisfactory results in the treatment of degenerative arthropathy of the rotator cuff and had a low rate of complications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S2255-4971(15)30347-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4799360PMC
April 2016

Data collapse, scaling functions, and analytical solutions of generalized growth models.

Phys Rev E Stat Nonlin Soft Matter Phys 2011 Jun 2;83(6 Pt 1):061902. Epub 2011 Jun 2.

Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil.

We consider a nontrivial one-species population dynamics model with finite and infinite carrying capacities. Time-dependent intrinsic and extrinsic growth rates are considered in these models. Through the model per capita growth rate we obtain a heuristic general procedure to generate scaling functions to collapse data into a simple linear behavior even if an extrinsic growth rate is included. With this data collapse, all the models studied become independent from the parameters and initial condition. Analytical solutions are found when time-dependent coefficients are considered. These solutions allow us to perceive nontrivial transitions between species extinction and survival and to calculate the transition's critical exponents. Considering an extrinsic growth rate as a cancer treatment, we show that the relevant quantity depends not only on the intensity of the treatment, but also on when the cancerous cell growth is maximum.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevE.83.061902DOI Listing
June 2011

COMPARATIVE ANATOMICAL STUDY BETWEEN THE RIGHT AND LEFT SIDES OF THE AXILLARY NERVE IN RELATION TO DELTOPECTORAL APPROACH AND ACROMION.

Rev Bras Ortop 2011 May-Jun;46(3):309-14. Epub 2015 Dec 8.

Attending Physicians in the Shoulder and Elbow Group, Orthopedics and Traumatology Service of the State of São Paulo Public Servants' Hospital (HSPE), São Paulo, Brazil.

Objective: To establish anatomical parameters for the axillary nerve by measuring the distances to the acromion and the deltopectoral access, and to ascertain whether there are any differences in comparative measurements between the left and right sides.

Method: An anatomical study on the path of the axillary nerve was conducted by dissecting 30 shoulders of 20 fresh adult cadavers. For comparative study, bilateral dissection was performed on 10 cadavers. Digital caliper gauges, accurate to the nearest 0.05 cm, were used to measure the distances between the lateral extremity of the acromion and the anterior and posterior branches of the axillary nerve, and between the deltopectoral space and the anterior branch of the axillary nerve.

Results: The shortest distance between the acromion and the axillary nerve was 5.47 cm, and the greatest distance was 7.06 cm. The shortest distance between the deltopectoral groove and the axillary nerve was 3.94 cm. A statistically significant difference was found using Wilcoxon's test in comparative measurements between the left and right sides for the distances between the posterior branch of the axillary nerve and the midpoint of the lateral border of the acromion (A-E), and between the anterior branch of the axillary nerve and the anterior extremity of the acromion (B-C), both of which were larger on the right side.

Conclusions: The axillary nerve was situated between 5.47 and 7.06 cm distally to the acromion, and 3.94 cm laterally to the deltopectoral space. There was a statistically significant difference in the comparison between the left and right sides, and both measurements were larger on the right side.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S2255-4971(15)30201-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4799228PMC
April 2016

Expectation propagation with factorizing distributions: a Gaussian approximation and performance results for simple models.

Neural Comput 2011 Apr 11;23(4):1047-69. Epub 2011 Jan 11.

Instituto de Física, Universidade de São Paulo, São Paulo, 05508-090, Brazil.

We discuss the expectation propagation (EP) algorithm for approximate Bayesian inference using a factorizing posterior approximation. For neural network models, we use a central limit theorem argument to make EP tractable when the number of parameters is large. For two types of models, we show that EP can achieve optimal generalization performance when data are drawn from a simple distribution.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1162/NECO_a_00104DOI Listing
April 2011

EVALUATION OF SURGICAL TREATMENT OF FRACTURES IN TWO OR THREE PARTS OF THE PROXIMAL HUMERUS WITH THE "PARACHUTE TECHNIQUE".

Rev Bras Ortop 2010 May-Jun;45(3):241-6. Epub 2015 Nov 17.

Collaborating Physician in the Shoulder Group, Orthopedics and Traumatology Service, HSPE-IAMSPE, Sao Paulo.

Objective: To evaluate the efficacy and safety of the surgical technique called the "parachute technique, as applied to adult patients who suffered displaced and unstable two or three-part fractures of the proximal humerus, through the clinical outcomes.

Methods: Between January 1995 and June 2006, 59 adult patients with displaced and unstable two or three-part fractures underwent operations performed by the Shoulder and Elbow Group of the Orthopedics and Traumatology Service of Hospital do Servidor Público Estadual de São Paulo using the "parachute technique. This method consists of an intramedullary tension band and extramedullary fixation in a figure-of-eight to join the fragments of the fracture, using a 6.5-millimeter spongy screw with partial threading, a washer and two non-absorbable wires, thereby producing stable synthesis with minimal aggression to the surrounding soft tissue and not requiring any subsequent removal of material. The final shape of this synthesis is reminiscent of the shape of an open parachute. The patients had a minimum postoperative follow-up of six months. For the diagnosis, trauma series radiographic views of the shoulder were produced. The fractures were classified in accordance with the system proposed by Neer. We used the scale of the University of California, Los Angeles (UCLA), to evaluate the results.

Results: The "parachute technique" produced good results in 47% and excellent results in 26% of the cases, according to the UCLA scores.

Conclusion: The "parachute technique" is a safe and effective treatment for displaced and unstable two or three-part fractures of the proximal humerus.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S2255-4971(15)30364-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4799108PMC
March 2016

Emergence and loss of assortative mating in sympatric speciation.

J Theor Biol 2009 Jun 13;258(3):465-77. Epub 2008 Dec 13.

Instituto de Física, Universidade de São Paulo, CP66318, CEP 05315-970, São Paulo, SP, Brazil.

We have studied an agent model which presents the emergence of sexual barriers through the onset of assortative mating, a condition that might lead to sympatric speciation. In the model, individuals are characterized by two traits, each determined by a single locus A or B. Heterozygotes on A are penalized by introducing an adaptive difference from homozygotes. Two niches are available. Each A homozygote is adapted to one of the niches. The second trait, called the marker trait has no bearing on the fitness. The model includes mating preferences, which are inherited from the mother and subject to random variations. A parameter controlling recombination probabilities of the two loci is also introduced. We study the phase diagram by means of simulations, in the space of parameters (adaptive difference, carrying capacity, recombination probability). Three phases are found, characterized by (i) assortative mating, (ii) extinction of one of the A alleles and (iii) Hardy-Weinberg like equilibrium. We also make perturbations of these phases to see how robust they are. Assortative mating can be gained or lost with changes that present hysteresis loops, showing the resulting equilibrium to have partial memory of the initial state and that the process of going from a polymorphic panmictic phase to a phase where assortative mating acts as sexual barrier can be described as a first-order transition.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jtbi.2008.11.027DOI Listing
June 2009
-->