Structured training in intraosseous infusion to improve potentially life saving skills in pediatric emergencies - Results of an open prospective national quality development project over 3 years

BACKGROUND: Children in emergencies need peripheral intravenous (IV) access in order to receive drugs or fluids. The success of IV access is associated with the age of patients and fails in up to 50% of children younger than 6 years. In such situations, it is essential that physicians and paramedics have a tool and easily learnable skills with a high chance of success. According to international guidelines intraosseous (IO) access would be the next step after failed IV access. Our hypothesis was that the success rate in IO puncturing can be improved by standardizing the training; so we developed an IO workshop. METHODS: Twenty-eight hospitals and ambulance services participated in an evaluation process over 3 years. IO workshops and the distribution of standardized IO sets were coordinated by the study group of the University Hospital of Berne. Any attempted or successful IO punctures were evaluated with a standardized interview. RESULTS: We investigated 35 applications in 30 patients (a total of 49 punctures) between November 2001 and December 2004. IO puncture was not successful in 5 patients. The success rate depended neither on the occupation nor the experience of users. Attendance at a standardized IO workshop increased the overall success rate from 77% to 100%, which was statistically not significant (P = 0.074). CONCLUSIONS: Standardized training in IO puncturing seems to improve success more than previous experience and occupation of providers. However, we could not show a significant increase in success rate after this training. Larger supranational studies are needed to show a significant impact of teaching on rarely used emergency skills.

Land use/cover change using Remote Sensing and Geographic Information Systems : Pic Macaya National Park, Haiti

A post classification change detection technique based on a hybrid classification approach (unsupervised and supervised) was applied to Landsat Thematic Mapper (TM), Landsat Enhanced Thematic Plus (ETM+), and ASTER images acquired in 1987, 2000 and 2004 respectively to map land use/cover changes in the Pic Macaya National Park in the southern region of Haiti. Each image was classified individually into six land use/cover classes: built-up, agriculture, herbaceous, open pine forest, mixed forest, and barren land using unsupervised ISODATA and maximum likelihood supervised classifiers with the aid of field collected ground truth data collected in the field. Ground truth information, collected in the field in December 2007, and including equalized stratified random points which were visual interpreted were used to assess the accuracy of the classification results. The overall accuracy of the land classification for each image was respectively: 1987 (82%), 2000 (82%), 2004 (87%). A post classification change detection technique was used to produce change images for 1987 to 2000, 1987 to 2004, and 2000 to 2004. It was found that significant changes in the land use/cover occurred over the 17- year period. The results showed increases in built up (from 10% to 17%) and herbaceous (from 5% to 14%) areas between 1987 and 2004. The increase of herbaceous was mostly caused by the abandonment of exhausted agriculture lands. At the same time, open pine forest and mixed forest areas lost (75%) and (83%) of their area to other land use/cover types. Open pine forest (from 20% to 14%) and mixed forest (from18 to 12%) were transformed into agriculture area or barren land. This study illustrated the continuing deforestation, land degradation and soil erosion in the region, which in turn is leading to decrease in vegetative cover. The study also showed the importance of Remote Sensing (RS) and Geographic Information System (GIS) technologies to estimate timely changes in the land use/cover, and to evaluate their causes in order to design an ecological based management plan for the park.

Comparison of three methods for driven pile capacity

A significant cost for foundations is the design and installation of piles when they are required due to poor ground conditions. Not only is it important that piles be designed properly, but also that the installation equipment and total cost be evaluated. To assist in the evaluation of piles a number of methods have been developed. In this research three of these methods were investigated, which were developed by the Federal Highway Administration, the US Corps of Engineers and the American Petroleum Institute (API). The results from these methods were entered into the program GRLWEAPTM to assess the pile drivability and to provide a standard base for comparing the three methods. An additional element of this research was to develop EXCEL spreadsheets to implement these three methods. Currently the Army Corps and API methods do not have publicly available software and must be performed manually, which requires that data is taken off of figures and tables, which can introduce error in the prediction of pile capacities. Following development of the EXCEL spreadsheet, they were validated with both manual calculations and existing data sets to ensure that the data output is correct. To evaluate the three pile capacity methods data was utilized from four project sites from North America. The data included site geotechnical data along with field determined pile capacities. In order to achieve a standard comparison of the data, the pile capacities and geotechnical data from the three methods were entered into GRLWEAPTM. The sites consisted of both cohesive and cohesionless soils; where one site was primarily cohesive, one was primarily cohesionless, and the other two consisted of inter-bedded cohesive and cohesionless soils. Based on this limited set of data the results indicated that the US Corps of Engineers method more closely compared with the field test data, followed by the API method to a lesser degree. The DRIVEN program compared favorably in cohesive soils, but over predicted in cohesionless material.

The Other Side of the Doors: Butte & Beyond -- Congressman Pat Williams “In the Crucible of Change”

Pat Williams emerged from the Mining City of Butte, Montana with a sense of grassroots, people-oriented politics. His inherent belief in the power of ordinary citizens carried him through the Montana Legislature and into Congress for a record-setting period. The accomplishments of his long career partially obscured his innate progressive and populist instinct that is reflective of the period of “in the Crucible of Change.” This film addresses Pat’s early years when his progressive instincts and activities resulted in pushback from the giant Anaconda Company which had held Montana hostage for 75 years. Pat is joined for part of the film by former campaign staffer, and now prominent media consultant, Michael Fenenbock for reflections on Pat’s 1978 “Door-to-Door to Congress” campaign, which demonstrated the power of his belief in the people on the other side of the doors. Pat Williams (b. 1937) rose from teaching grade school in his hometown of Butte, MT, to serving for the longest number of consecutive terms (9 terms, 18 years) in the US House of Representatives of anyone in Montana history. Pat was a member of the National Guard and attended UM in Missoula and William Jewel College, graduating from the University of Denver. Pat also served in the Montana legislature for 2 terms (1966 & 1968 elections). In 1969. Pat helped his legislative seat-mate John Melcher get elected as Montana’s Eastern District Congressman in the Special Election that June. Pat went to Washington DC as Melcher’s Executive Assistant. Upon returning to Montana, Pat headed up the Montana offices of the innovative Mountain Plains Family Education Program. In 1974, Pat ran unsuccessfully for Montana’s Western District Congressional seat in a three-way race with former Congressman Arnold Olsen and state Legislator Max Baucus. After the drafting and passage of the 1972 Montana Constitution, Pat was named a member of Montana’s first-ever Reapportionment Commission. In 1978 he successfully ran for Congress, conducting a massive grass-roots door-to-door campaign of 1½ years, reaching 50,000 doors. In a hotly contested 6-way Democratic primary, Pat won going away and also handily won the general election. Pat served in Congress from January, 1979 until January of 1997, 14 years representing the Western District and 4 years representing the entire state. Upon his retirement from Congress, in 1997 Williams returned to Montana where has been an instructor at the University of Montana and Senior Fellow and Regional Policy Associate at the Center for the Rocky Mountain West. He is a former member of the Montana Board of Regents and serves on a number of national education-related boards. In Congress Pat was a Deputy Whip of the U.S. House of Representatives and sat on committees on: Budget, Natural Resources, Education and Labor, and Agriculture. Pat’s leadership helped pass trailblazing legislation to assist hard-working middle-class families and ensure opportunities for every child. Pat’s fingerprints are on many pieces of important legislation, including the College Middle Income Assistance Act, the Family and Medical Leave Act, the Toddlers and Childhood Disability Act, the Library Services and Construction Act, and the Museum Services Act. Pat successfully sponsored the Lee Metcalf Wilderness Area and the Rattlesnake Wilderness area, helped save the Bob Marshall Wilderness from oil and gas exploration, and helped ban geothermal energy drilling near the borders of Yellowstone National Park. As Chairman of The Post-Secondary Education Committee, he protected the National Endowment for the Arts from elimination, a remarkable undertaking during a very trying time for the Agency. Pat worked tirelessly with Tribal College Leaders to build Montana’s seven Tribal Colleges. He was also responsible for the legislation that created The American Conservation Corps, which became the Corporation for National Service, giving thousands of America’s young people a chance to serve their country and pursue higher education. Pat lives in Missoula with his wife Carol Griffith Williams, former Montana Senate Majority Leader. They have three children and five grandchildren.

Computer-aided diagnosis of carotid atherosclerosis based on ultrasound image statistics, laws' texture and neural networks

Quantitative characterisation of carotid atherosclerosis and classification into symptomatic or asymptomatic is crucial in planning optimal treatment of atheromatous plaque. The computer-aided diagnosis (CAD) system described in this paper can analyse ultrasound (US) images of carotid artery and classify them into symptomatic or asymptomatic based on their echogenicity characteristics. The CAD system consists of three modules: a) the feature extraction module, where first-order statistical (FOS) features and Laws' texture energy can be estimated, b) the dimensionality reduction module, where the number of features can be reduced using analysis of variance (ANOVA), and c) the classifier module consisting of a neural network (NN) trained by a novel hybrid method based on genetic algorithms (GAs) along with the back propagation algorithm. The hybrid method is able to select the most robust features, to adjust automatically the NN architecture and to optimise the classification performance. The performance is measured by the accuracy, sensitivity, specificity and the area under the receiver-operating characteristic (ROC) curve. The CAD design and development is based on images from 54 symptomatic and 54 asymptomatic plaques. This study demonstrates the ability of a CAD system based on US image analysis and a hybrid trained NN to identify atheromatous plaques at high risk of stroke.

Chemotherapy for isolated locoregional recurrence of breast cancer (CALOR): a randomised trial.

BACKGROUND Patients with isolated locoregional recurrences (ILRR) of breast cancer have a high risk of distant metastasis and death from breast cancer. We aimed to establish whether adjuvant chemotherapy improves the outcome of such patients. METHODS The CALOR trial was a pragmatic, open-label, randomised trial that accrued patients with histologically proven and completely excised ILRR after unilateral breast cancer who had undergone a mastectomy or lumpectomy with clear surgical margins. Eligible patients were enrolled from hospitals worldwide and were centrally randomised (1:1) to chemotherapy (type selected by the investigator; multidrug for at least four courses recommended) or no chemotherapy, using permuted blocks, and stratified by previous chemotherapy, oestrogen-receptor and progesterone-receptor status, and location of ILRR. Patients with oestrogen-receptor-positive ILRR received adjuvant endocrine therapy, radiation therapy was mandated for patients with microscopically involved surgical margins, and anti-HER2 therapy was optional. The primary endpoint was disease-free survival. All analyses were by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00074152. FINDINGS From Aug 22, 2003, to Jan 31, 2010, 85 patients were randomly assigned to receive chemotherapy and 77 were assigned to no chemotherapy. At a median follow-up of 4·9 years (IQR 3·6-6 ·0), 24 (28%) patients had disease-free survival events in the chemotherapy group compared with 34 (44%) in the no chemotherapy group. 5-year disease-free survival was 69% (95% CI 56-79) with chemotherapy versus 57% (44-67) without chemotherapy (hazard ratio 0·59 [95% CI 0·35-0·99]; p=0·046). Adjuvant chemotherapy was significantly more effective for women with oestrogen-receptor-negative ILRR (pinteraction=0·046), but analyses of disease-free survival according to the oestrogen-receptor status of the primary tumour were not statistically significant (pinteraction=0·43). Of the 81 patients who received chemotherapy, 12 (15%) had serious adverse events. The most common adverse events were neutropenia, febrile neutropenia, and intestinal infection. INTERPRETATION Adjuvant chemotherapy should be recommended for patients with completely resected ILRR of breast cancer, especially if the recurrence is oestrogen-receptor negative. FUNDING US Department of Health and Human Services, Swiss Group for Clinical Cancer Research (SAKK), Frontier Science and Technology Research Foundation, Australian and New Zealand Breast Cancer Trials Group, Swedish Cancer Society, Oncosuisse, Cancer Association of South Africa, Foundation for Clinical Research of Eastern Switzerland (OSKK), Grupo Español de Investigación en Cáncer de Mama (GEICAM), and the Dutch Breast Cancer Trialists' Group (BOOG).

Divergent evolutionary processes associated with colonization of offshore islands

Oceanic islands have been a test ground for evolutionary theory, but here, we focus on the possibilities for evolutionary study created by offshore islands. These can be colonized through various means and by a wide range of species, including those with low dispersal capabilities. We use morphology, modern and ancient sequences of cytochrome b (cytb) and microsatellite genotypes to examine colonization history and evolutionary change associated with occupation of the Orkney archipelago by the common vole (Microtus arvalis), a species found in continental Europe but not in Britain. Among possible colonization scenarios, our results are most consistent with human introduction at least 5100 bp (confirmed by radiocarbon dating). We used approximate Bayesian computation of population history to infer the coast of Belgium as the possible source and estimated the evolutionary timescale using a Bayesian coalescent approach. We showed substantial morphological divergence of the island populations, including a size increase presumably driven by selection and reduced microsatellite variation likely reflecting founder events and genetic drift. More surprisingly, our results suggest that a recent and widespread cytb replacement event in the continental source area purged cytb variation there, whereas the ancestral diversity is largely retained in the colonized islands as a genetic ‘ark’. The replacement event in the continental M. arvalis was probably triggered by anthropogenic causes (land-use change). Our studies illustrate that small offshore islands can act as field laboratories for studying various evolutionary processes over relatively short timescales, informing about the mainland source area as well as the island.

Aminoacyl-tRNA synthetases: Probing the molecular basis of catalysis and discrimination

Aminoacyl-tRNA synthetases (RSs) are responsible for the essential connection of amino acids with trinucleotide sequences of tRNA's. The RS family constitutes two structurally dissimilar groups of proteins, class I and class II. Methionyl-tRNA synthetase (MetRS) and isoleucyl-tRNA synthetase (IleRS), both members of class I, were the focus of this work. Both enzymes are zinc-containing proteins; show a high degree of amino acid specificity; and edit activated noncognate amino acids, thereby ensuring the fidelity of the genetic code. The goals of this work were to further delineate the molecular basis of catalysis and discrimination in these enzymes by mapping active site geometries using high-resolution nuclear magnetic resonance spectroscopy (NMR).^ Internuclear distances obtained from transferred nuclear Overhauser effects were used to define the conformations of Mg($\alpha$,$\beta$-methylene)ATP bound to E. coli MetRS and E. coli IleRS in multiple complexes. Identical conformations were found for the bound ATP. Thus, the predicted structural homology between IleRS and MetRS is supported by consensus enzyme-bound nucleotide conformations. The conformation of the bound nucleotide is not sensitive to occupation of the amino acid site of MetRS or IleRS. Therefore, conformational changes known to occur in the synthetases upon ligand binding appear not to alter the bound conformation of the adenosine portion of the nucleotide. Nuclear Overhauser effects on the substrate amino acid L-selenomethionine were also used to evaluate the enzyme-bound conformation of the cognate amino acid. The amino acid assumes a conformation which is consistent with a proposed editing mechanism.^ The E. coli MetRS was shown to catalyze amino acid $\alpha$-proton exchange in the presence of deuterium oxide of all cognate amino acids. It is proposed that the enzyme-bound zinc coordinates the $\alpha$-carboxylate of the amino acid, rendering the $\alpha$-proton more acidic. An enzymic base is responsible for exchange of the $\alpha$-proton. This proposal suggests that the enzyme-bound zinc may have a role in amino acid discrimination in MetRS. However, the role of this exchange reaction in catalysis remains unknown. ^

What does your neighbourhood say about you? A study of life expectancy in 1.3 million Swiss neighbourhoods

BACKGROUND Switzerland had the highest life expectancy at 82.8 years among the Organisation for Economic Co-operation and Development (OECD) countries in 2011. Geographical variation of life expectancy and its relation to the socioeconomic position of neighbourhoods are, however, not well understood. METHODS We analysed the Swiss National Cohort, which linked the 2000 census with mortality records 2000-2008 to estimate life expectancy across neighbourhoods. A neighbourhood index of socioeconomic position (SEP) based on the median rent, education and occupation of household heads and crowding was calculated for 1.3 million overlapping neighbourhoods of 50 households. We used skew-normal regression models, including the index and additionally marital status, education, nationality, religion and occupation to calculate crude and adjusted estimates of life expectancy at age 30 years. RESULTS Based on over 4.5 million individuals and over 400 000 deaths, estimates of life expectancy at age 30 in neighbourhoods ranged from 46.9 to 54.2 years in men and from 53.5 to 57.2 years in women. The correlation between life expectancy and neighbourhood SEP was strong (r=0.95 in men and r=0.94 women, both p values <0.0001). In a comparison of the lowest with the highest percentile of neighbourhood SEP, the crude difference in life expectancy from skew-normal regression was 4.5 years in men and 2.5 years in women. The corresponding adjusted differences were 2.8 and 1.9 years, respectively (all p values <0.0001). CONCLUSIONS Although life expectancy is high in Switzerland, there is substantial geographical variation and life expectancy is strongly associated with the social standing of neighbourhoods.

Reevaluation of the MASTER-2009 MLI and H-10 Debris Modeling

The current paper is an excerpt from the doctoral thesis ”Multi-Layer Insulation as Contribution to Orbital Debris”written at the Institute of Aerospace Systems of the Technische Universit ̈at of Braunschweig. The Multi-Layer In-sulation (MLI) population included in ESA’s MASTER-2009 (M eteoroid and Space-Debris Terrestrial Environment Reference) software is based on models for two mechanisms: One model simulates the release of MLI debris during fragmentation events while another estimates the continuo us release of larger MLI pieces due to aging related deterioration of the material. The aim of the thesis was to revise the MLI models from the base up followed by a re-validation of the simulated MLI debris population. The validation is based on comparison to measurement data of the GEO and GTO debris environment obtained by the Astronomical Institute of the University of Bern (AIUB) using ESA’s Space Debris Telescope (ESASDT), the 1-m Zeiss telescope located at the Optical Ground Station (OGS) at the Teide Observatory at Tenerife, Spain. The re-validation led to the conclusion that MLI may cover a much smaller portion of the observed objects than previously published. Further investigation of the resulting discrepancy revealed that the contribution of altogether nine known Ariane H-10 upper stage explosion events which occurred between 1984 and 2002 has very likely been underestimated in past simulations.

Statistical and methodological challenges for disaster preparedness and medical needs assessment in Rio Grande Valley of Texas

In recent years, disaster preparedness through assessment of medical and special needs persons (MSNP) has taken a center place in public eye in effect of frequent natural disasters such as hurricanes, storm surge or tsunami due to climate change and increased human activity on our planet. Statistical methods complex survey design and analysis have equally gained significance as a consequence. However, there exist many challenges still, to infer such assessments over the target population for policy level advocacy and implementation. ^ Objective. This study discusses the use of some of the statistical methods for disaster preparedness and medical needs assessment to facilitate local and state governments for its policy level decision making and logistic support to avoid any loss of life and property in future calamities. ^ Methods. In order to obtain precise and unbiased estimates for Medical Special Needs Persons (MSNP) and disaster preparedness for evacuation in Rio Grande Valley (RGV) of Texas, a stratified and cluster-randomized multi-stage sampling design was implemented. US School of Public Health, Brownsville surveyed 3088 households in three counties namely Cameron, Hidalgo, and Willacy. Multiple statistical methods were implemented and estimates were obtained taking into count probability of selection and clustering effects. Statistical methods for data analysis discussed were Multivariate Linear Regression (MLR), Survey Linear Regression (Svy-Reg), Generalized Estimation Equation (GEE) and Multilevel Mixed Models (MLM) all with and without sampling weights. ^ Results. Estimated population for RGV was 1,146,796. There were 51.5% female, 90% Hispanic, 73% married, 56% unemployed and 37% with their personal transport. 40% people attained education up to elementary school, another 42% reaching high school and only 18% went to college. Median household income is less than $15,000/year. MSNP estimated to be 44,196 (3.98%) [95% CI: 39,029; 51,123]. All statistical models are in concordance with MSNP estimates ranging from 44,000 to 48,000. MSNP estimates for statistical methods are: MLR (47,707; 95% CI: 42,462; 52,999), MLR with weights (45,882; 95% CI: 39,792; 51,972), Bootstrap Regression (47,730; 95% CI: 41,629; 53,785), GEE (47,649; 95% CI: 41,629; 53,670), GEE with weights (45,076; 95% CI: 39,029; 51,123), Svy-Reg (44,196; 95% CI: 40,004; 48,390) and MLM (46,513; 95% CI: 39,869; 53,157). ^ Conclusion. RGV is a flood zone, most susceptible to hurricanes and other natural disasters. People in the region are mostly Hispanic, under-educated with least income levels in the U.S. In case of any disaster people in large are incapacitated with only 37% have their personal transport to take care of MSNP. Local and state government’s intervention in terms of planning, preparation and support for evacuation is necessary in any such disaster to avoid loss of precious human life. ^ Key words: Complex Surveys, statistical methods, multilevel models, cluster randomized, sampling weights, raking, survey regression, generalized estimation equations (GEE), random effects, Intracluster correlation coefficient (ICC).^

Ordenamiento territorial y desarrollo local : provincia Cercado, Tarija, Bolivia

El proceso de ordenamiento territorial en Bolivia es relativamente nuevo y por tal razón el avance es mínimo si se piensa en los objetivos alcanzados hasta ahora. El presente trabajo pretende mostrar el avance logrado en uno de los departamentos de Bolivia, Tarija, donde en 5 años, se ha logrado elaborar un plan departamental de ordenamiento territorial y mediante la coordinación interinstitucional (prefectura y gobiernos municipales) se ha iniciado el mismo proceso de a nivel municipal. A partir de estos planes municipales se induce a municipios predominantemente urbanos a trabajar planes de ordenamiento territorial a partir de lineamientos planteados desde la prefectura, con el fin de iniciar los procesos de planificación urbana, actualizar la normativa y elaborar proyectos de desarrollo local. El objetivo del presente trabajo, es mostrar los avances a los que se pretende arribar gracias a un proceso metodológico de ordenamiento territorial incorporado a una dinámica urbana que interactúa constantemente con su área de influencia que en el caso boliviano es normalmente rural; pero además demostrar que el componente interdisciplinario en el caso de la planificación urbana es imprescindible considerando que hasta hace unos años este era un trabajo especifico de los colegas urbanistas y que en una realidad como la latinoamericana casi siempre quedaba en planos y en un viejo anaquel. Por lo tanto a partir de una interdisciplinariedad se puede lograr desarrollo local articulando y optimizando relaciones urbano-rurales que basan su desarrollo en un proceso metodológico como es el caso del ordenamiento territorial. El trabajo, se apoya en la guía metodológica para la elaboración de planes elaboradas por el Ministerio de Desarrollo Sostenible del gobierno boliviano, pero como tal cual su nombre expresa es una guía susceptible a ser adecuada a las exigencias del área de estudio, en este sentido sobre esa base es que se incorporan algunas variables de estudio que permitirán mejorar el producto a nivel de propuesta una vez concluido el trabajo. Contempla varias etapas donde la incorporación de los diferentes actores sociales será una clave para lograr resultados exitosos en la etapa de implementación. Actualmente el plan municipal de la provincia Cercado, es un proyecto a encarar en los próximos meses una vez cumplidos con los requisitos administrativos para iniciar el trabajo técnico que comprenderá un trabajo de campo, para el relevamiento de datos, la elaboración de un diagnóstico integral con dos ámbitos territoriales rural y urbano, para luego proceder al análisis territorial y el planteamiento de propuesta que incluirán políticas, estrategias, acciones y proyectos, pero no solo generará bases para el uso de suelo y la ocupación del territorio, a escala urbana se plantearan los lineamientos para el diseño y la normativa urbana. A partir del cual se definirán proyectos de desarrollo local que nos permita orientarnos hacia la imagen objetivo planteada en la visión del proyecto, este trabajo incluye el aspecto institucional para fortalecer al proceso que hasta esta ahora se encuentra desarticulado; se pretende consolidar el proceso de ordenamiento y dar inicio a otros en escalas de mayor detalle permitiendo la optimización de recursos y el aprovechamiento de las potencialidades y recursos naturales para mejorar la calidad de vida.

Pulperos y pulperías rurales bonaerenses : Su influencia en la campaña y los pueblos, 1780-1820

En las últimas décadas se ha construido una nueva imagen del mundo rural pampeano que ha complejizado el análisis con nuevos temas, métodos y fuentes. En estos estudios si bien los pulperos y pulperías están presentes siempre figuran de manera lateral o complementaria. En este trabajo me propuse profundizar el estudio de pulperos y pulperías rurales una vez reconocida su influencia en materia económica, política y social tanto en la campaña en su conjunto como hacia el interior de los pueblos. El tema elegido entonces responde a la necesidad de un estudio exclusivo y exhaustivo sobre un grupo que entendemos ha cumplido una función muy relevante como elemento central en la expansión, ocupación y estructuración de la sociedad rural bonaerense al igual que lo fueron las estancias, los fuertes y las parroquias. La expansión y consolidación de la campaña bonaerense ha sido acompañada por el despliegue comercial en las últimas décadas del siglo XVIII. Podemos hablar de un fenómeno de retroalimentación entre comerciantes y explotaciones ganaderas protagonizado con frecuencia por las mismas personas. En este sentido las pulperías contribuyeron a la formación de pueblos, la ocupación de nuevas tierras y el desarrollo de relaciones pacíficas con los pueblos originarios, aunque a veces fueron agentes disruptores. Nos queda claro que las pulperías eran engranajes importantes dentro de la economía local y ubicaban a sus propietarios por encima de la mayoría de los productores. Sin embargo muchos pulperos también eran productores o viceversa y esa diversificación les permitía disminuir los riesgos y las posibilidades de "naufragio". Creemos haber matizado y en algunos casos rechazado algunas de las imágenes literarias que en general configuraron una visión muy negativa de los pulperos y sus negocios. El pulpero no era muy distinto a su clientela y formaba parte de las costumbres predominantes de la campaña más allá de tener, en muchos casos, una posición económica más holgada. En este sentido, muchos pulperos fueron vecinos referentes en sus pueblos cumpliendo distintas funciones más allá de la fundamental que era el abastecimiento de bienes básicos, ocuparon cargos en el andamiaje institucional y se erigieron en la "voz del pueblo". La posición privilegiada de algunos pulperos les permitía evadir el peso de la justicia y cuando ocupaban cargos sacar provecho de ellos. Esto refuerza la idea de connivencia entre comercializadores locales y el aparato institucional local en torno al usufructo del tráfico de cueros que cada vez se hacía más rentable.

Ocupantes y propietarios durante la expansión de la frontera en la provincia de Buenos Aires, Argentina, 1780-1860

A partir de la fundación de la ciudad de Buenos Aires en el siglo XVI, la ocupación del espacio provincial se realizó a expensas de las tribus autóctonas que habitaban las regiones pampeana y patagónica. Desde fines del siglo XVIII, y durante todo el XIX, la población hispano-criolla realizó sucesivos avances para incorporar estas tierras a la estructura productiva que se vinculaba al mercado internacional. En este trabajo analizamos la cuestión de la ocupación sin títulos de la tierra como un problema persistente en esa frontera que se expandía. Para ello hemos focalizado nuestro estudio en dos momentos y lugares diferentes: Chascomús (1780-1838) y Bragado (1846-1860). Estos casos nos permiten demostrar la permanencia de los establecimientos productivos sin respaldo legal a medida que se fueron cerrando las posibilidades de acceder a la propiedad plena de la tierra, insistiendo en que la primitiva ocupación y la posterior legalización del dominio fueron dos procesos permanentes, complementarios y conflictivos hasta fines del siglo XIX