Comparative Forelimb Muscle Function in Turtles: Tests of Environmental Variation and Neuromotor Conservation

Novel locomotor functions in animals may evolve through changes in morphology, muscle activity, or a combination of both. The idea that new functions or behaviors can arise solely through changes in structure, without concurrent changes in the patterns of muscle activity that control movement of those structures, has been formalized as the `neuromotor conservation hypothesis\u27. In vertebrate locomotor systems, evidence for neuromotor conservation is found across transitions in terrestrial species and into fliers, but transitions in aquatic species have received little comparable study to determine if changes in morphology and muscle function were coordinated through the evolution of new locomotor behaviors. Understanding how animals move has long been an important component of integrative comparative biology and biomechanics. This topic can be divided into two components, the motion of the limbs, and the muscles that move them. Variation in these two parameters of movement is typically examined at three levels, intraspecfic studies of different behaviors, and interspecific studies on either the same or different behaviors. My dissertation is a compilation of four studies that examined forelimb kinematics and motor control across locomotor modes in freshwater and marine turtles to determine how muscle function is modulated in the evolution of new locomotor styles. First, I described patterns of forelimb motion and associated patterns of muscle activation during swimming and walking in a generalized freshwater turtle species (Trachemys scripta) to show how muscle function is modulated to accommodate the different performance demands imposed by water and land. Second, I examined whether differences in muscle function are correlated with changes in limb morphology and locomotor style by comparing forelimb kinematics and motor patterns of swimming from rowing Trachemys scripta to those of flapping sea turtles (Caretta caretta). Next, I quantified forelimb kinematics of swimming in the freshwater turtle species Carettochelys insculpta, describing how it uses synchronous forelimb movements to swim and whether these motions are actually similar to the flapping kinematics of sea turtles (Caretta caretta) or if they more closely resemble the kinematics of freshwater species with which they are more phylogenetically similar. I also compared the kinematics of rowing in Trachemys scripta and the highly aquatic Florida softshell turtle (Apalone ferox). Finally, I compared patterns of forelimb muscle activation for four species of turtles to determine whether the chelonian lineage shows evidence of neuromotor conservation across the evolution of different locomotor modes. Data from these studies help improve our understanding of how new forms of quadrupedal locomotion have evolved

Political competition in dual economies : clientelism in Latin America

RESUMEN: Esta investigación sugiere que un incremento del 10% en los niveles de democracia en América Latina reduce hasta en 0.6% el nivel de emisiones per capita de CO2 (calidad ambiental). Esta relación se estima mediante un sistema de ecuaciones de panel de datos aplicado a 19 países latinoamericanos en el periodo 1995-2008. La democracia actúa como un medio para las crecientes demandas de calidad ambiental en América Latina causadas por el incremento en la población urbana y niveles de desarrollo. Sin embargo, esta investigación tiene, por lo menos, dos limitaciones: primero, no analiza la relación de largo plazo entre democracia y calidad ambiental en América Latina; y, segundo, este estudio supone que la democracia es un sistema político solo con consecuencias positivas.ABSTARCT: This study finds that a 10% increase in the level of democracy in Latin America reduces (raises) CO2 emissions per capita (environmental quality) by up to 0.6%. This relationship is estimated by using a fixed effects panel system of equations for 19 Latin American countries in the period 1995-2008. Democracy serves as a conduit for increasing demands on environmental quality in Latin America, due to increases in urban population and prosperity. Nevertheless, this study has, at least, two caveats: first it cannot unveil the long run relationship between democracy and environmental quality in Latin America; and, secondly, this study assumes that democracy entails positives outcomes for countries adopting this political system

Cliometrics : a market account of a scientific community, 1957-2005

RESUMEN: Este artículo tiene como objetivo evaluar las principales contribuciones de la cliometría en la integración global y disciplinaria de las ciencias sociales. A través de una analogía de un pseudo-mercado del conocimiento son analizadas las presiones y respuestas que los cliometristas han enfrentado en tanto una empresa cuyo objetivo es proveer respuestas a ciertas preguntas que la sociedad formula. Basado en una valoración general de los productos cliométricos se encuentra que esta comunidad científica norteamericana revolucionó la práctica de la historia económica y ganó terreno frente a la competencia representada por la historia tradicional. Posteriormente, los cliometristas difundieron sus innovaciones internacionalmente, pero atravesaron divisiones internas que en última instancia han enriquecido sus prácticas y llamado a cooperar con otras comunidades científicas.ABSTRACT: This paper aims at assessing the main contributions of cliometrics toward the global and disciplinary integration of social sciences. Through an analogy of a pseudomarket of knowledge it develops an analysis of pressures and responses that cliometricians have faced insofar as an enterprise whose goal is to provide answers to certain questions that society asks. Based on a general appraisal of cliometric-like products, it is found that this U.S. scientific community revolutionized the practice of economic history and gained terrain before the competing traditional history. Subsequently, cliometricians spread their innovations internationally but got through internal divisions which ultimately have enriched their practices and prompted them to cooperate with other scientific communities

Economic policy and institutional change : a context-specific model for explaining the economic reforms failure in 1970's Colombia

ABSTARCT: This paper develops a context-specific model (Greif, 1997) to analyze the case of failed market-oriented reform in Colombia during 1974-78. The methodology keeps the contextual specificity at a manageable level, which is no more than the institutional structure under consideration, while it tries to maintain a parsimonious model. The theoretical framework is inscribed in the rational choice approach and game theory. This paper raises a standard question in economic reforms literature: why did the reforms fail? More comprehensively, what impeded progressive institutional change in this case? The answer is based on modelling theoretically and historically the strategic dilemmas brought about by the reforms and internacional shocks. Government appears here as an inflexible agenda setter poorly endowed; Coffee as the dominant player whose short-run interests won through, and Industry as the weak player who openly opposed to policies that the G-Cs coalition set out with the 1976 coffee boom. Ultimately the reforms failed because of Government‟s poor understanding of and limited autonomy for solving the dilemmas “economic reforms vs. coffee boom”, “Non-coffee sectors vs. Coffee sector”, and “Short-run vs. Long-run economic growth”

Forelimb kinematics during swimming in the pig-nosed turtle, Carettochelys insculpta, compared with other turtle taxa: rowing versus flapping, convergenceversus intermediacy

Animals that swim using appendages do so by way of rowing and/or flapping motions. Often considered discrete categories, rowing and flapping are more appropriately regarded as points along a continuum. The pig-nosed turtle, Carettochelys insculpta, is unusual in that it is the only freshwater turtle to have limbs modified into flippers and swim via synchronous forelimb motions that resemble dorsoventral flapping, traits that evolved independently from their presence in sea turtles. We used high-speed videography to quantify forelimb kinematics in C. insculpta and a closely related, highly aquatic rower (Apalone ferox). Comparisons of our new data with those previously collected for a generalized freshwater rower (Trachemys scripta) and a flapping sea turtle (Caretta caretta) allow us to: (1) more precisely quantify and characterize the range of limb motions used by flappers versus rowers, and (2) assess whether the synchronous forelimb motions of C. insculpta can be classified as flapping (i.e. whether they exhibit forelimb kinematics and angles of attack more similar to closely related rowing species or more distantly related flapping sea turtles). We found that the forelimb kinematics of previously recognized rowers (T. scripta and A. ferox) were most similar to each other, but that those of C. insculpta were more similar to rowers than to flapping C. caretta. Nevertheless, of the three freshwater species, C. insculpta was most similar to flapping C. caretta. ‘Flapping’ in C. insculpta is achieved through humeral kinematics very different from those in C. caretta, with C. insculpta exhibiting significantly more anteroposterior humeral motion and protraction, and significantly less dorsoventral humeral motion and depression. Based on several intermediate kinematic parameters and angle of attack data, C. insculpta may in fact represent a synchronous rower or hybrid rower-flapper, suggesting that traditional views of C. insculpta as a flapper should be revised

Aquatic turning performance of painted turtles (Chrysemys picta) and functional consequences of a rigid body design

The ability to capture prey and avoid predation in aquatic habitats depends strongly on the ability to perform unsteady maneuvers (e.g. turns), which itself depends strongly on body flexibility. Two previous studies of turning performance in rigid-bodied taxa have found either high maneuverability or high agility, but not both. However, examinations of aquatic turning performance in rigid-bodied animals have had limited taxonomic scope and, as such, the effects of many body shapes and designs on aquatic maneuverability and agility have yet to be examined. Turtles represent the oldest extant lineage of rigid-bodied vertebrates and the only aquatic rigid-bodied tetrapods. We evaluated the aquatic turning performance of painted turtles, Chrysemys picta (Schneider, 1783) using the minimum length-specific radius of the turning path (R/L) and the average turning rate (ωavg) as measures of maneuverability and agility, respectively. We filmed turtles conducting forward and backward turns in an aquatic arena. Each type of turn was executed using a different pattern of limb movements. During forward turns, turtles consistently protracted the inboard forelimb and held it stationary into the flow, while continuing to move the outboard forelimb and both hindlimbs as in rectilinear swimming. The limb movements of backward turns were more complex than those of forward turns, but involved near simultaneous retraction and protraction of contralateral fore- and hindlimbs, respectively. Forward turns had a minimum R/L of 0.0018 (the second single lowest value reported from any animal) and a maximum ωavg of 247.1°. Values of R/L for backward turns (0.0091-0.0950 L) were much less variable than that of forward turns (0.0018-1.0442 L). The maneuverability of turtles is similar to that recorded previously for rigidbodied boxfish. However, several morphological features of turtles (e.g. shell morphology and limb position) appear to increase agility relative to the body design of boxfish

UX-for Smart-PSS: Towards a Context-Aware Framework

Smart-product service systems are a business strategy that combines product and service into one value proposition. The user experience of digital services and the smart product can be a clear differentiator among competitors to achieve economically sustainable solutions. Hence, offering a more personalized experience is an important aspect of S-PSS. This paper aims to provide a theoretical framework for a context-aware user experience in S-PSS by providing adaptive and personalized services to the users according to their needs in a given context, by exploiting the digital capabilities of smart products and referring to the use of recommendation systems. The paper presents an application scenario using a smart-wearable as an example of a product-oriented PSS to better describe the framework and each component while stating the future challenges

Context-awareness for the design of Smart-product service systems: Literature review

Smart-Product Service Systems (S-PSS) emerge as a novel strategy to integrate smart products with advanced digital capabilities and their related e-services to satisfy user’s needs in highly context-dependent environments. S-PSS has the potential to generate a transition towards more economically, ecologically and socially sustainable practices and business models due to its adaptive capacities. However, being able to exploit the digital capabilities of smart products and their services is still limited in design and even more to improve the user experience. For this reason, this study will focus on the Context-awareness capability that has been defined by multiple scholars as one of the most relevant properties that defines the smartness of a product. Following a systematic literature review approach, this work makes the following contributions: (1) it provides a bibliometric analysis using a cluster keyword map to analyze the most researched topics in S-PSS relevant to the design, user experience and analyze their connections; (2) an analysis of the case studies presented in the literature according to the life cycle of context-aware applications; and (3) establishes a research direction for the user experience and design of the S-PSS

Optimizing a Passive Tracking Solar Panel System

For a solar panel to function efficiently, it must turn to face the sun throughout the day. Usually, an electronic device rotates a solar panel. In this experiment, hourly rotation of the panel was achieved through contraction of a shape memory alloy (SMA) and a gear system. A Fresnel lens directed the sun\u27s rays onto the SMA causing it to contract. A delayed reset system was built to turn the panel from west to east at the end of the day. In addition, this project investigated different materials to properly heat and cool the SMA within the plexiglass housing apparatus. The overall goal for the project was to automatically power an appliance on campus with solar energy

Glycomic analysis of high density lipoprotein shows a highly sialylated particle.

Many of the functional proteins and lipids in high density lipoprotein (HDL) particles are potentially glycosylated, yet very little is known about the glycoconjugates of HDL. In this study, HDL was isolated from plasma by sequential micro-ultracentrifugation, followed by glycoprotein and glycolipid analysis. N-Glycans, glycopeptides, and gangliosides were extracted and purified followed by analysis with nano-HPLC Chip quadrupole time of flight mass spectrometry and MS/MS. HDL particles were found to be highly sialylated. Most of the N-glycans (∼90%) from HDL glycoproteins were sialylated with one or two neuraminic acids (Neu5Ac). The most abundant N-glycan was a biantennary complex type glycan with two sialic acids (Hexose5HexNAc4Neu5Ac2) and was found in multiple glycoproteins using site-specific glycosylation analysis. The observed O-glycans were all sialylated, and most contained a core 1 structure with two Neu5Acs, including those that were associated with apolipoprotein CIII (ApoC-III) and fetuin A. GM3 (monosialoganglioside, NeuAc2-3Gal1-4Glc-Cer) and GD3 (disialoganglioside, NeuAc2-8NeuAc2-3Gal1-4Glc-Cer) were the major gangliosides in HDL. A 60% GM3 and 40% GD3 distribution was observed. Both GM3 and GD3 were composed of heterogeneous ceramide lipid tails, including d18:1/16:0 and d18:1/23:0. This report describes for the first time a glycomic approach for analyzing HDL, highlighting that HDL are highly sialylated particles