Determinant factors to discriminate the body weight loss in overweight people

Introduction. Most studies have described how the weight loss is when different treatments are compared (1-3), while others have also compared the weight loss by sex (4), or have taken into account psychosocial (5) and lifestyle (6, 7) variables. However, no studies have examined the interaction of different variables and the importance of them in the weight loss. Objective. Create a model to discriminate the range of weight loss, determining the importance of each variable. Methods. 89 overweight people (BMI: 25-29.9 kg?m-2), aged from 18 to 50 years, participated in the study. Four types of treatments were randomly assigned: strength training (S), endurance training (E), strength and endurance training (SE), and control group (C). All participants followed a 25% calorie restriction diet. Two multivariate discriminant models including the variables age, sex, height, daily energy expenditure (EE), type of treatment (T), caloric restriction (CR), initial body weight (BW), initial fat mass (FM), initial muscle mass (MM) and initial bone mineral density (BMD) were performed having into account two groups: the first and fourth quartile of the % of weight loss in the first model; the groups above and below the mean of the % of weight loss in the second model. The discriminant models were built using the inclusion method in SPSS allowing us to find a function that could predict the body weight loss range that an overweight person could achieve in a 6 months weight loss intervention.Results. The first discriminant analysis predicted that a combination of the studied variables would discriminate between the two ranges of body weight loss with 81.4% of correct classification. The discriminant function obtained was (Wilks? Lambda=0.475, p=0.003): Discriminant score=-18.266-(0.060xage)- (1.282xsex[0=female;1=male])+(14.701xheight)+(0.002xEE)- (0.006xT[1=S;2=E;3=SE;4=C])-(0.047xCR)- (0.558xBW)+(0.475xFM)+(0.398xMM)+(3.499xBMD) The second discriminant model obtained would discriminate between the two groups of body weight loss with 74.4% of correct classification. The discriminant function obtained was (Wilks? Lambda=0.725, p=0.005): Discriminant score=-5.021-(0.052xage)- (0.543xsex[0=female;1=male])+(3.530xheight)+(0.001xEE)- (0.493xT[1=S;2=E;3=SE;4=C])+(0.003xCR)- (0.365xBW)+(0.368xFM)+(0.296xMM)+(4.034xBMD) Conclusion. The first developed model could predict the percentage of weight loss in the following way: if the discriminant score is close to 1.051, the range of weight loss will be from 7.44 to -4.64% and if it is close to - 1.003, the range will be from -11.03 to -25,00% of the initial body weight. With the second model if the discriminant score is close to 0.623 the body weight loss will be above -7.93% and if it is close to -0.595 will be below - 7.93% of the initial body weight. References. 1. Brochu M, et al. Resistance training does not contribute to improving the metabolic profile after a 6-month weight loss program in overweight and obese postmenopausal women. J Clin Endocrinol Metab. 2009 Sep;94(9):3226-33. 2. Del Corral P, et al. Effect of dietary adherence with or without exercise on weight loss: a mechanistic approach to a global problem. J Clin Endocrinol Metab. 2009 May;94(5):1602-7. 3. Larson-Meyer DE, et al. Caloric Restriction with or without Exercise: The Fitness vs. Fatness Debate. Med Sci Sports Exerc. 2010;42(1):152-9. 4. Hagan RD, et al. The effects of aerobic conditioning and/or caloric restriction in overweight men and women. Medicine & Science in Sports & Exercise. 1986;18(1):87-94. 5. Teixeira PJ, et al. Mediators of weight loss and weight loss maintenance in middle-aged women. Obesity (Silver Spring). 2010 Apr;18(4):725-35. 6. Bautista-Castano I, et al. Variables predictive of adherence to diet and physical activity recommendations in the treatment of obesity and overweight, in a group of Spanish subjects. Int J Obes Relat Metab Disord. 2004 May;28(5):697-705.

La luz natural como generadora del espacio arquitect��nico de la catedral g��tica

La historia de la construcci��n de las catedrales g��ticas es la historia de la b��squeda de la luz. Esta afirmaci��n casi metaf��sica, recoge una realidad asumida por todos los historiadores tanto de la arquitectura antigua como del resto de las artes. La luz en el g��tico ha sido descrita bajo m��ltiples matices como son su car��cter simb��lico, crom��tico e incluso m��stico, sin embargo no existe, en el estudio del conocimiento de la luz g��tica, ninguna referencia a la misma como realidad f��sica cuantificable, cualificable y por tanto, clasificable. La presente tesis doctoral aborda el concepto de la iluminaci��n g��tica desde una perspectiva nueva. Demuestra, con un m��todo anal��tico in��dito, que la iluminaci��n g��tica es cuantificable y cualificable. Para ello analiza en profundidad la iluminaci��n de una selecci��n de 6 edificios muestra, las catedrales de Gerona, Toledo, Sevilla y Le��n, la bas��lica de Santa Mar��a del Mar y la capilla de la Sainte Chapelle de Par��s, mediante una toma de datos ���in situ��� de iluminaci��n y su comparaci��n con los datos lum��nicos obtenidos por un programa de soleamiento de la simulaci��n en tres dimensiones de los distintos proyectos originales g��ticos. El an��lisis exhaustivo de las muestras y su introducci��n en el m��todo anal��tico descrito, permite determinar, en primer lugar, unas cualidades in��ditas que identifican la luz de los espacios g��ticos seg��n unos par��metros nuevos como son la intensidad, expresividad, recorrido, distorsi��n y color. Tambi��n describe cuales son los factores determinantes, de nuevo in��ditos, que modulan cada una de las cualidades y en que proporci��n lo hacen cada uno de ellos. Una vez establecidas las cualidades y los factores que las definen, la tesis doctoral establece los rangos en los que se mueven las distintas cualidades y que conformar��n la definitiva clasificaci��n seg��n ���tipos de cualidad lum��nica���. Adicionalmente, la tesis propone un procedimiento abreviado de acercamiento a la realidad de la iluminaci��n g��tica a trav��s de unas f��rmulas matem��ticas que relacionan los factores geom��tricos detectados y descritos en la tesis con el resultado luminoso del espacio en lo que concierne a las dos cualidades m��s importantes de las reflejadas, la intensidad y la expresividad. Gracias a este m��todo y su procedimiento abreviado, la clasificaci��n se hace extensible al resto de catedrales g��ticas del panorama espa��ol y europeo y abre el camino a nuevas clasificaciones de edificios hist��ricos de distintas ��pocas, iniciando un apasionante camino por recorrer en la recuperaci��n de ���la luz original���. Esta clasificaci��n y sus cualidades podr��n a su vez, ser utilizadas como herramientas de conocimiento de un factor determinante a la hora de describir cualquier espacio g��tico y su aportaci��n pretende ser un nuevo condicionante a tener en cuenta en el futuro, ayudando a entender y respetar, en las posibles intervenciones a realizar sobre el patrimonio arquitect��nico, aquello que fue en su inicio motor principal del proyecto arquitect��nico y que hoy d��a no se valora suficientemente tan solo por falta de conocimiento: su luz. The history of the construction of the Gothic cathedrals is the history of the search for light. This almost etaphysical statement reflects a reality accepted by all historians both of ancient architecture and other arts. Light in the Gothic period has been described under multiple approaches such as its symbolic, chromatic and even mystical character. However, in the study of the Gothic light, no references exist to it as a physical quantifiable and qualifiable reality and therefore, classifiable. This dissertation deals with the concept of Gothic light from a new perspective. With a new analytical method, it shows that Gothic lighting is quantifiable and can be classified regarding quality. To this end, a selection of 6 buildings light samples are analyzed; the cathedrals of Gerona, Toledo, Seville and Le��n, the basilica of Santa Mar��a of the Sea and the Sainte Chapelle in Paris. "In situ" lighting data is collected and it is compared with lighting data obtained by a program of sunlight of the 3D simulation of various Gothic original projects. The comprehensive analysis of the samples and the data introduced in the analytical method described, allows determining, first, important qualities that identify the light of Gothic spaces according to new parameters such as intensity, expressiveness, trajectory, distortion and color. It also describes the determinant factors, which modulate each of the qualities and in what proportion they do it. Once the qualities and factors that define them have been established, in this doctoral dissertation the ranges regarding different qualities are set, which will make up the final classification according to "types of light quality". In addition, this work proposes an abbreviated procedure approach to the reality of the Gothic lighting through some mathematical formulae, relating the geometric factors identified and described in the study with the bright result of space regarding the two most important qualities of the light,intensity and expressiveness. Thanks to this method and to the abbreviated procedure, the classification can be applied to other Spanish and European Gothic cathedrals and opens up the way to new classifications of historic buildings from different eras, starting an exciting road ahead in the recovery of the "original light". This classification and its qualities may in turn be used as tools to know a determinant factor when describing any Gothic space. Its contribution is intended to be a new conditioning factor to keep in mind in the future, helping to understand and respect, in possible interventions on the architectural heritage, what was the main engine to start the architectural project and which today is not valued enough due to the lack knowledge: the light.

Thermal, stress, and traps effects in AlGaN/GaN HEMTs

GaN y AlN son materiales semiconductores piezoel��ctricos del grupo III-V. La heterouni��n AlGaN/GaN presenta una elevada carga de polarizaci��n tanto piezoel��ctrica como espont��nea en la intercara, lo que genera en su cercan��a un 2DEG de grandes concentraci��n y movilidad. Este 2DEG produce una muy alta potencia de salida, que a su vez genera una elevada temperatura de red. Las tensiones de puerta y drenador provocan un stress piezoel��ctrico inverso, que puede afectar a la carga de polarizaci��n piezoel��ctrica y as�� influir la densidad 2DEG y las caracter��sticas de salida. Por tanto, la f��sica del dispositivo es relevante para todos sus aspectos el��ctricos, t��rmicos y mec��nicos. En esta tesis se utiliza el software comercial COMSOL, basado en el m��todo de elementos finitos (FEM), para simular el comportamiento integral electro-t��rmico, electro-mec��nico y electro-t��rmico-mec��nico de los HEMTs de GaN. Las partes de acoplamiento incluyen el modelo de deriva y difusi��n para el transporte electr��nico, la conducci��n t��rmica y el efecto piezoel��ctrico. Mediante simulaciones y algunas caracterizaciones experimentales de los dispositivos, hemos analizado los efectos t��rmicos, de deformaci��n y de trampas. Se ha estudiado el impacto de la geometr��a del dispositivo en su auto-calentamiento mediante simulaciones electro-t��rmicas y algunas caracterizaciones el��ctricas. Entre los resultados m��s sobresalientes, encontramos que para la misma potencia de salida la distancia entre los contactos de puerta y drenador influye en generaci��n de calor en el canal, y as�� en su temperatura. El diamante posee une elevada conductividad t��rmica. Integrando el diamante en el dispositivo se puede dispersar el calor producido y as�� reducir el auto-calentamiento, al respecto de lo cual se han realizado diversas simulaciones electro-t��rmicas. Si la integraci��n del diamante es en la parte superior del transistor, los factores determinantes para la capacidad disipadora son el espesor de la capa de diamante, su conductividad t��rmica y su distancia a la fuente de calor. Este procedimiento de disipaci��n superior tambi��n puede reducir el impacto de la barrera t��rmica de intercara entre la capa adaptadora (buffer) y el substrato. La muy reducida conductividad el��ctrica del diamante permite que pueda contactar directamente el metal de puerta (muy cercano a la fuente de calor), lo que resulta muy conveniente para reducir el auto-calentamiento del dispositivo con polarizaci��n pulsada. Por otra parte se simul�� el dispositivo con diamante depositado en surcos atacados sobre el sustrato como caminos de disipaci��n de calor (disipador posterior). Aqu�� aparece una competencia de factores que influyen en la capacidad de disipaci��n, a saber, el surco atacado contribuye a aumentar la temperatura del dispositivo debido al peque��o tama��o del disipador, mientras que el diamante disminuir��a esa temperatura gracias a su elevada conductividad t��rmica. Por tanto, se precisan capas de diamante relativamente gruesas para reducer ele efecto de auto-calentamiento. Se compar�� la simulaci��n de la deformaci��n local en el borde de la puerta del lado cercano al drenador con estructuras de puerta est��ndar y con field plate, que podr��an ser muy relevantes respecto a fallos mec��nicos del dispositivo. Otras simulaciones se enfocaron al efecto de la deformaci��n intr��nseca de la capa de diamante en el comportamiento el��ctrico del dispositivo. Se han comparado los resultados de las simulaciones de la deformaci��n y las caracter��sticas el��ctricas de salida con datos experimentales obtenidos por espectroscop��a micro-Raman y medidas el��ctricas, respectivamente. Los resultados muestran el stress intr��nseco en la capa producido por la distribuci��n no uniforme del 2DEG en el canal y la regi��n de acceso. Adem��s de aumentar la potencia de salida del dispositivo, la deformaci��n intr��nseca en la capa de diamante podr��a mejorar la fiabilidad del dispositivo modulando la deformaci��n local en el borde de la puerta del lado del drenador. Finalmente, tambi��n se han simulado en este trabajo los efectos de trampas localizados en la superficie, el buffer y la barrera. Las medidas pulsadas muestran que tanto las puertas largas como las grandes separaciones entre los contactos de puerta y drenador aumentan el cociente entre la corriente pulsada frente a la corriente continua (lag ratio), es decir, disminuir el colapse de corriente (current collapse). Este efecto ha sido explicado mediante las simulaciones de los efectos de trampa de superficie. Por su parte, las referidas a trampas en el buffer se enfocaron en los efectos de atrapamiento din��mico, y su impacto en el auto-calentamiento del dispositivo. Se presenta tambi��n un modelo que describe el atrapamiento y liberaci��n de trampas en la barrera: mientras que el atrapamiento se debe a un t��nel directo del electr��n desde el metal de puerta, el desatrapamiento consiste en la emisi��n del electr��n en la banda de conducci��n mediante t��nel asistido por fonones. El modelo tambi��n simula la corriente de puerta, debida a la emisi��n electr��nica dependiente de la temperatura y el campo el��ctrico. Adem��s, tambi��n se ilustra la corriente de drenador dependiente de la temperatura y el campo el��ctrico. ABSTRACT GaN and AlN are group III-V piezoelectric semiconductor materials. The AlGaN/GaN heterojunction presents large piezoelectric and spontaneous polarization charge at the interface, leading to high 2DEG density close to the interface. A high power output would be obtained due to the high 2DEG density and mobility, which leads to elevated lattice temperature. The gate and drain biases induce converse piezoelectric stress that can influence the piezoelectric polarization charge and further influence the 2DEG density and output characteristics. Therefore, the device physics is relevant to all the electrical, thermal, and mechanical aspects. In this dissertation, by using the commercial finite-element-method (FEM) software COMSOL, we achieved the GaN HEMTs simulation with electro-thermal, electro-mechanical, and electro-thermo-mechanical full coupling. The coupling parts include the drift-diffusion model for the electron transport, the thermal conduction, and the piezoelectric effect. By simulations and some experimental characterizations, we have studied the device thermal, stress, and traps effects described in the following. The device geometry impact on the self-heating was studied by electro-thermal simulations and electrical characterizations. Among the obtained interesting results, we found that, for same power output, the distance between the gate and drain contact can influence distribution of the heat generation in the channel and thus influence the channel temperature. Diamond possesses high thermal conductivity. Integrated diamond with the device can spread the generated heat and thus potentially reduce the device self-heating effect. Electro-thermal simulations on this topic were performed. For the diamond integration on top of the device (top-side heat spreading), the determinant factors for the heat spreading ability are the diamond thickness, its thermal conductivity, and its distance to the heat source. The top-side heat spreading can also reduce the impact of thermal boundary resistance between the buffer and the substrate on the device thermal behavior. The very low electrical conductivity of diamond allows that it can directly contact the gate metal (which is very close to the heat source), being quite convenient to reduce the self-heating for the device under pulsed bias. Also, the diamond coated in vias etched in the substrate as heat spreading path (back-side heat spreading) was simulated. A competing mechanism influences the heat spreading ability, i.e., the etched vias would increase the device temperature due to the reduced heat sink while the coated diamond would decrease the device temperature due to its higher thermal conductivity. Therefore, relative thick coated diamond is needed in order to reduce the self-heating effect. The simulated local stress at the gate edge of the drain side for the device with standard and field plate gate structure were compared, which would be relevant to the device mechanical failure. Other stress simulations focused on the intrinsic stress in the diamond capping layer impact on the device electrical behaviors. The simulated stress and electrical output characteristics were compared to experimental data obtained by micro-Raman spectroscopy and electrical characterization, respectively. Results showed that the intrinsic stress in the capping layer caused the non-uniform distribution of 2DEG in the channel and the access region. Besides the enhancement of the device power output, intrinsic stress in the capping layer can potentially improve the device reliability by modulating the local stress at the gate edge of the drain side. Finally, the surface, buffer, and barrier traps effects were simulated in this work. Pulsed measurements showed that long gates and distances between gate and drain contact can increase the gate lag ratio (decrease the current collapse). This was explained by simulations on the surface traps effect. The simulations on buffer traps effects focused on illustrating the dynamic trapping/detrapping in the buffer and the self-heating impact on the device transient drain current. A model was presented to describe the trapping and detrapping in the barrier. The trapping was the electron direct tunneling from the gate metal while the detrapping was the electron emission into the conduction band described by phonon-assisted tunneling. The reverse gate current was simulated based on this model, whose mechanism can be attributed to the temperature and electric field dependent electron emission in the barrier. Furthermore, the mechanism of the device bias via the self-heating and electric field impact on the electron emission and the transient drain current were also illustrated.

An��lisis de la durabilidad de la cubierta plana invertida, a trav��s del estudio de las interacciones e incompatibilidades entre las membranas sint��ticas y el poliestireno extrusionado

La cubierta plana invertida se forma, cuando sobre una membrana impermeable se coloca un aislamiento t��rmico. Estos materiales pueden separarse con capas auxiliares que impiden el contacto directo entre ellos. Muchos de los materiales que forman esta soluci��n constructiva pueden ser pol��meros, como lo son algunas membranas impermeables, las capas auxiliares separadoras o el poliestireno extrusionado (XPS). La mayor��a de los pol��meros son incompatibles entre s��, por lo que en esta tesis se plantea como hip��tesis la posibilidad de que se produzcan interacciones e incompatibilidades entre algunos de estos materiales. Por ello se hace una b��squeda bibliogr��fica y documental de otras investigaciones que pudieran estar relacionadas con el tema, y se estudian y analizan normas y documentaci��n facilitada por fabricantes. Sin embargo, tras consultar toda la bibliograf��a y documentaci��n que se referencia en esta tesis doctoral, no fue encontrado ning��n trabajo de investigaci��n sobre la influencia de la interacci��n entre los materiales que componen las cubiertas planas invertidas, y de c��mo afecta esta a la durabilidad de las mismas. El prop��sito de esta tesis es el an��lisis de la durabilidad de la cubierta plana invertida, desde el punto de vista de las interacciones e incompatibilidades que pueden producirse entre los materiales formantes de esta soluci��n constructiva. Adem��s de este objetivo general, se estudian alternativas que puedan prolongar el ciclo de vida de la cubierta plana invertida. Para ello, se desarrolla un plan experimental con el fin de analizar dichas incompatibilidades, y estudiar los factores que las condicionan. Algunos de los resultados obtenidos, muestran que determinadas l��minas impermeables utilizadas normalmente para la construcci��n de cubiertas planas, pueden interactuar con el XPS y sufrir deterioro. El contacto con el mismo, la incorrecta separaci��n, la presi��n y el calor, son factores determinantes para que se produzca deterioro. Se puede se��alar como una de las conclusiones de esta investigaci��n, que la protecci��n t��rmica que proporciona el XPS a la cubierta plana invertida, puede no ser suficiente (dependiendo del espesor del mismo, y de la ubicaci��n de la cubierta fundamentalmente), para reducir la cantidad de calor que alcanza la l��nea de contacto entre los materiales, y por tanto paliar las interacciones que se producen. Adem��s, aunque los geotextiles utilizados como capas auxiliares separadoras, en los gramajes por metro cuadrado, recomendados por algunas de las normas reguladoras de este tipo de cubiertas minoran las interacciones, estas siguen produci��ndose. ABSTRACT The inverted flat roof is formed from a waterproofing membrane on which the thermal insulation is placed. These materials may be separated with auxiliary layers, which prevent the direct contact between them. Many of the materials forming this constructive solution can be polymers, such as some waterproofing membranes, the auxiliary separating layers, or the extruded polystyrene board (XPS). Most polymers are incompatible, so this thesis hypothesized that interactions and incompatibilities between some of these materials might be possible. Therefore, a literature search, and other documentation that could be related to the topic, are studied and analyzed, as well as, standards and documentation provided by manufacturers. However, after consulting all literature and documents referenced in this dissertation, it was not found any research about the influence of interaction between the materials forming the inverted flat roof, and how this affects to the durability of them. The purpose of this thesis is the analysis of the durability of the inverted flat roof, from the point of view of interactions and incompatibilities may occur between the materials setting up this constructive solution. Along with this general objective, alternatives that can prolong the life cycle of the inverted roof are studied. To get this, an experimental plan is developed, in order to analyze these incompatibilities, and study the factors conditioning them. Some of the results show, that certain normally used waterproofing laminas for building flat roofs, may interact with XPS producing lamina deterioration. Contact, incorrect separation, pressure and heat, are determinant factors for degradation. It can be pointed out, as one of the conclusions of this research, that the thermal protection provided by XPS to the inverted flat roof, cannot be enough (depending on the XPS thickness, and the location of the flat mainly) to reduce the amount of heat that reaches the contact line between materials, and thus to cut down interactions. Furthermore, although geotextiles used as auxiliary separating layers, within the weights per square meter recommended by some of the regulating rules of this type of roofs reduce interactions, these still occur.

Habitar al borde del agua : villas del siglo XX

Las casas del siglo XX construidas al borde del mar ���escenario ��nico y origen de su expresi��n- siguen la topograf��a del suelo que habitan en su descenso al agua, y organizan espacios que obtienen miradas al horizonte marino. El horizonte nos confronta a lo desconocido. La vista del mar incita al deseo de recorrerlo, al deseo de viajar. Con origen en el otium romano, la presencia del agua define un modo de vida apacible ���epic��reo- que los viajeros de la arquitectura -que nos acompa��an en la tesis- traducen en sus refugios m��s ��ntimos. Experimentan con los cambios en los conceptos y en las t��cnicas, que se trasladan f��cilmente a la arquitectura de la casa al borde del agua desde los inicios del Movimiento Moderno. Sus espacios del habitar frente al mar nos permiten descubrir estrategias comunes en sus respuestas m��s modernas. El arquitecto ante el proyecto frente al mar llega a la ubicaci��n elegida, mira hacia el horizonte, y desplaz��ndose ladera arriba se coloca en un punto estrat��gico que elige; despu��s, delante de su tablero, recorre el camino inverso, coloca el lugar y sobre ��l dibuja los elementos que configurar��n los espacios de la casa buscando esa mirada al mar. Las situaciones y ubicaciones posibles son infinitas; se definen algunas consonancias espaciales comunes en los suelos que se ocupan debidas a la presencia del mar que asociamos entre s��. De la comparaci��n entre todas las casas -emblemas del XX-, surgen m��ltiples variantes de la mirada y de espacios al abierto, y modos de fabricar entornos con criterios comunes para dominar la visi��n del mar. Interiores que se abren al panorama, espacios cuyas ventanas buscan su mirada en la extensi��n del horizonte, rescisiones y aperturas. Reconocemos condicionantes en el territorio a los que las villas responden, categor��as arquitect��nicas que dan respuesta frente al mar en la b��squeda del moderno, la topograf��a, la mirada y el espacio al abierto. Las casas comparten la idea del dominio del paisaje desde el punto m��s alto, y en algunos suelos se invierte la tipolog��a por la topograf��a, confirmando as�� un criterio com��n basado en la lectura del suelo como consecuencia de la b��squeda del espacio de la mirada. Los espacios al abierto se significan en todas ellas, son espacios al -aire libre- abiertos, unos envueltos, otros porticados, puertas del horizonte que se abren al exterior, en el techo de la casa, otros cubiertos y abiertos, espacios entre interior y exterior, en plataformas con bancales o patios envolventes, recintos o habitaciones abiertas. Descubrimos un logro del XX en los espacios positivos o negativos que traducen o juegan con el entorno, que ocupan o sustraen de los contornos construidos y que obtienen espacios intermedios en la b��squeda de la relaci��n con el mar. Las herramientas que se utilizan son los dibujos de los autores, de las casas visitadas, el elenco de viajeros y sus viajes, el conocimiento desde el estudio de los proyectos. A trav��s de la comparaci��n por aproximaciones parciales, los dibujos nos definen la mirada al mar, el modo de ocupaci��n y la forma de relaci��n con el paisaje. La arquitectura del habitar frente al mar en el XX, hecha para y por arquitectos, topograf��a el suelo y construye la mirada, fabricando espacios al abierto en la relaci��n entre la casa y el entorno mar��timo. ABSTRACT Houses of the 20th century built by the sea ��� a unique setting which gives rise to their expression ��� follow the topography of the land they occupy in its descent towards the sea, and they organize spaces which give views of the maritime horizon. The horizon brings us face to face with the unknown. The sea view provokes a desire to cross it, to travel. The presence of the sea defines a peaceful, epicurean way of life, with origins in the Roman otium, which architectural travellers ��� who accompany us through the thesis ��� translate into their most intimate retreats. They experiment with changes in concepts and techniques, which are easily transferred to the architecture of the seaside house since the beginnings of the Modern Movement. Their living spaces allow us to discover common strategies in the most modern responses. The architect with a seaside project arrives at the site, looks towards the horizon, then walks uphill and chooses a strategic point; then with his drawing board he retraces his steps, he sets the position and then draws in the elements that make up the house that seeks a sea view. The number of potential situations and locations is infinite; certain common spatial accordances are defined in land which is occupied due to the presence of the sea. Comparison of all the houses ��� 20th century emblems ��� throws up multiple variations of view and open spaces, and ways of creating settings with common criteria so as to command the vision of the sea. Interiors which open up to the panorama, spaces whose windows seek their view in the expanse of the horizon, openings and closures. We recognise determinant factors in the territory to which the villas respond, architectural categories which give a seaside solution to the search for the modern, the topography, the view, and the open space. The houses share the idea of dominating the landscape from the highest point, and in some areas typology and topography are inverted, thus confirming a common criteria based on the reading of the ground as a conse quence of the search for the view space. Open spaces stand out in all the villas ��� spaces open to the outdoor air - some are wrapped, some arcaded, doors to the horizon which open up to the exterior, on the roof of the house. There are open and covered spaces, spaces between the exterior and interior, on platforms with banks and surrounding patios, enclosures and open rooms. We discover an achievement of the 20th century in the positive and negative spaces which translate and play with the setting, which occupy or are extracted from built contours and which obtain intermediate spaces in the search for the relationship with the sea. The tools used are the author���s drawings of the houses visited, the cast of travelling companions and their travels, the knowledge gained from study of the projects. Through comparison by means of partial approaches, the drawings define the view of the sea, the occupation mode and the way of relating to the landscape. Architecture for living by the sea in the 20th century, carried out both by and for the architects, shapes the land and constructs the view, creating open spaces in the relationship between the house and the sea surroundings.