Unravelling the genetic mechanisms and paleoenvironmental controls of early Cretaceous Oyster Mass occurrences (OMOs), Neuquén Basin, west-central Argentina Toscano, Agustina Gabriela; Lazo, Dario Gustavo; Schwarz, Ernesto Lower Valanginian oyster mass occurrences (OMOs) from the Neuqu en Basin of Argentina are analyzed using a multidisciplinary approach, including the description of their sedimentological signature and stratigraphic contacts, assessment of taphonomical attributes, and paleontological and paleoecologicalcharacteristics. These OMOs present a wide distribution in the study area, with lateral continuity for at least 2.5 km and up to 12 m thick. They occur within a single stratigraphic interval, constrained in terms of sequence stratigraphy and biostratigraphy. Three stacked tabular OMOs separated by mudstone levels were recorded in all the studied localities. The associated lithofacies point to a mainly outer ramp paleoenvironment, below storm wave base and occasionally disturbed by exceptional, distal storm flows.Internally, the OMOs share a common vertical trend characterized, from base to top, by a gradual increase in oyster abundance and a transition from mainly reclining, disarticulated oysters to articulated, cementing oysters conforming build-ups. Hence, a mainly biogenic origin is proposed, with autobiostromes grading vertically to bioherms. This vertical trend was interpreted in terms of development stages, namely, colonization, expansion, climax and extinction, which were in turn related to specifi paleoenvironmental controls. Particularly, the OMOs establishment and development were associated to low sedimentation rates, salinity fluctuations and high nutrient input as a result of high primary productivity.At a larger scale, the overall paleoenvironmental conditions and subtropical geographical position of the basin were detrimental for most reef builders typical of the Cretaceous period (e.g., corals, sponges, rudists), and could have favored oyster proliferation and OMOs development instead.

Effects of urbanization-related disturbances on macroinvertebrate communities in a Patagonian river system: insights from a functional approach Williams Subiza, Emilio Adolfo; Brand, Cecilia; Assef, Yanina Andrea; Grech, Marta Gladys; Miserendino, Maria Laura The expansion of urban areas has led to land-use changes that affect aquatic biodiversity and ecosystem processes through several ways, such as increased runoff, water pollution, habitat homogenization, and disturbance of the natural flow. It is well known that urbanization induces profound changes in freshwater macroinvertebrate communities, but relatively few studies have approached this topic using trait-based methods. This severely limits our ability to monitor and predict potential alterations of ecosystem processes. We here provide empirical evidence about the effects of urbanization-related changes on the trait composition and functional diversity of freshwater macroinvertebrates from Patagonia (Argentina). Macroinvertebrate sampling and environmental characterization were carried out in 13 study sites distributed across three water courses in the Futaleufú river basin. We found changes in environmental conditions over the urban impact gradient, in turn accompanied by variation in functional diversity and trait composition of aquatic macroinvertebrates. Specifically, we detected lower functional diversity in urban and post-urban reaches, mainly attributed to shifts in the distribution of taxa within the functional space, rather to the extirpation of functionally distinct taxa located at the edges of it (i.e., func- tional evenness and dispersion decreased, but functional richness remained constant). We also found signs of functional homogenization at the most impaired sites, where gatherers and tegument-breathing taxa dominated. These changes were mainly explained by conductivity, biological oxygen demand, and oxygen levels in the water column.

Study of the properties of a composite material Fe78Si9B13 / GNP in an epoxy matrix Pagnola, Marcelo Rubén; Useche, Jairo; Faig, Javier Alejandro; Ferrari, Sergio; Martinez Garcia, Ricardo This study investigates the properties of a composite material obtained by mixing Fe78Si9B13 metallic powders (at %) with graphene nanoplates (GNP) in an epoxy matrix. Four composite types were created with GNP weight proportions of 0%, 0.5%, 1.0%, and 1.5%. The composites were embedded in transparent epoxy with weight proportions of 10%, 15%, and 20%, and then filled into 7 x 20 mm cylindrical probes. Twelve samples were prepared, and another 12 samples were subjected to a longitudinal magnetic field of 1 kG. All samples were tested with a Universal Testing Machine (Model WDW 10E) up to a maximum force of 20 kN. The experiment recorded deformation (∆H) vs. load force. Most samples showed a maximum compression resistance of 390 MPa, except for a few that did not exceed 100 MPa. The magnetically oriented samples showed a greater elastic limit in the range of 200 to 270 MPa. Optical microscopy was used to observe the ordering of the particles after the application of the magnetic field. Scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction were used to characterize the structure of the composite components. A vibrating sample magnetometer (VSM) was used to characterize the magnetic behavior of the metallic powders in the composite.

Primeras miradas: Victoria Ocampo como escritora y gestora cultural en la prensa de los años veinte; First Looks: Victoria Ocampo as a Writer and Cultural Manager in the Press of the 1920s González, María Soledad Este artículo se propone indagar, desde la disciplina histórica, los primeros pasos de Victoria Ocampo en la esfera pública a partir de la articulación entre escritura y gestión y, las tempranas recepciones que suscitó en la prensa. Desde la recuperación de algunas notas periodísticas de la época, pasajes de Testimonios y de “Viraje”, cuarto volumen de su Autobiografía, junto a ciertas entradas en su correspondencia, se intenta dialogar con el contexto de los años veinte en el escenario nacional y transnacional.; This article aims to investigate, from the field of historical discipline, the first steps of Victoria Ocampo in the public sphere based on the articulation of writing and management and the early receptions it aroused in the press. From the recovery of some journalistic notes of the time, passages from Testimonies and “Viraje”, the fourth volume of his Autobiography, together with certain entries in his correspondence, attempts to dialogue with the context of the 1920s on the national and transnational stage.

Afectados Ambientales y el Conflicto por los “Basurales Petroleros” en la Provincia de Neuquén, Argentina Acacio, Juan Antonio El avance de la frontera hidrocarburífera en Argentina se expresa, desde el año 2013, en el desarrollo de la actividad para extraer hidrocarburos no convencionales mediante la técnica de la fractura hidráulica, o fracking. Esta actividad cobró relevancia en Neuquén, donde el sector petrolero tiene centralidad en la economía y permea en la vida política, social y cultural de la provincia. Con el inicio de la explotación se desarrollaron en varios puntos de la provincia conflictos de distinta intensidad debido a los impactos ambientales, en la salud y en la alteración de la vida cotidiana de distintos grupos sociales que esta actividad genera. El presente trabajo analiza, desde una perspectiva sociológica cualitativa, y de la mano de los aportes de la ecología política, el conflicto y el proceso organizativo de afectados ambientales que generó la expansión de las plantas de tratamiento de los desechos de la industria hidrocarburífera en la periferia de la ciudad de Neuquén.

Spatial modeling tool to assess and rank peri-urban land use in an agricultural region of the Midwestern United States Agost, Lisandro; Velázquez, Guillermo Ángel America is the continent with the largest area of genetically modified crops, the United States being the leading producer. Numerous studies show a panorama of potential exposure from agricultural pesticide use for this types of crops near to cities across a vast region of the United States. For the reasons mentioned above, we have chosen to investigate the following issues in this study: How does the implementation of an indexbased spatial modeling tool effectively rank the proximity of peri-urban crops, and what factors impact its effectiveness across diverse peri-urban agricultural landscapes? To address these questions, the research employs the Crop Proximity Index (CPI) model in various cities across the Midwest region of the United States. Six hundred and seventy cities in the state of Iowa were selected, and their peripheries were analysed using weighted perimeter rings, from 0 to 2000 m. The Crop Proximity Index was used to simulate a model of proximity to crops by considering the spatial quantification occupied by agriculture, forest cover, shrubs, pastures and buffer zones. This index varies from 0 to 1 and serves to rank the cities under study. It was estimated that a Crop Proximity Index equal to or >0.8 is a good approximation to a model with less proximity of crops and that only 62 cities (9%) meet this condition. Some 457 cities (68%) have CPIs equal to or <0.5 due to the large areas of crops and the low peripheral forest levels. The CPI is an index that makes it possible to obtain vital exploratory data in order to focus on future research that would determine how the proximity of agro-industrial crops has possible negative consequences for the environment and human health in greater detail.

Conversación pública sobre vacunas en la pandemia de covid-19 en Argentina, 2021–2022; Public conversation on vaccines during the covid-19 pandemic in Argentina, 2021–2022 Demonte, Flavia Carolina; Bruno, Daniela; Lozano, Leandro; Mena, Maria Florencia; Pereira, Andrés Ante la caída de las coberturas vacunales y la circulación informativa sobre salud, las conversaciones en el entorno público/mediático digital constituyen un ámbito de estudio relevante para el campo de la comunicación en salud. A través de un estudio cualitativo, basado en el análisis de publicaciones del gobierno, la prensa digital y las redes sociales, caracterizamos la conversación pública sobre vacunas –en términos de temas, momentos, ejes y encuadres en Argentina en el período 2020-2021– signada por el debate sobre las vacunas covid-19. Los resultados muestran que la conversación pública se centralizó en la vacunación contra el covid-19, se estructuró en dos momentos diferenciados (producción de vacunas y campaña de vacunación) y bajo encuadres morales sustentados en la vacunación como práctica de cuidado y la ciencia como voz autorizada. En simultáneo, las dudas sobre la seguridad y eficacia de las vacunas estructuraron argumentos de reticencia vacunal, que entendemos como parte de prácticas extendidas, asociadas con las desconfianzas hacia las instituciones y reinterpretaciones del conocimiento científico y del cuidado.; In the face of declining vaccination coverage and the dissemination of health-related information, conversations in the public/mediatic digital sphere constitute a relevant study area for the field of health communication. Through a qualitative study based on the analysis of government publications, digital press, and social media, we characterize the public conversation on vaccines – in terms of topics, moments, axes, and framings in Argentina during the 2020-2021 period – marked by the debate on covid-19 vaccines. The results show that public conversation focused on covid-19 vaccination, structured in two distinct moments (vaccine production and vaccination campaign), and under moral framings grounded in vaccination as a care practice and science as an authoritative voice. Simultaneously, doubts about the safety and efficacy of vaccines shaped arguments of vaccine hesitancy, which we understand as part of extended practices associated with distrust towards institutions and reinterpretations of scientific knowledge and care.

Conversación pública sobre vacunas en la pandemia de covid-19 en Argentina, 2021–2022; Public conversation on vaccines during the covid-19 pandemic in Argentina, 2021–2022 Demonte, Flavia Carolina; Bruno, Daniela; Lozano, Leandro; Mena, Maria Florencia; Pereira, Andrés Ante la caída de las coberturas vacunales y la circulación informativa sobre salud, las conversaciones en el entorno público/mediático digital constituyen un ámbito de estudio relevante para el campo de la comunicación en salud. A través de un estudio cualitativo, basado en el análisis de publicaciones del gobierno, la prensa digital y las redes sociales, caracterizamos la conversación pública sobre vacunas –en términos de temas, momentos, ejes y encuadres en Argentina en el período 2020-2021– signada por el debate sobre las vacunas covid-19. Los resultados muestran que la conversación pública se centralizó en la vacunación contra el covid-19, se estructuró en dos momentos diferenciados (producción de vacunas y campaña de vacunación) y bajo encuadres morales sustentados en la vacunación como práctica de cuidado y la ciencia como voz autorizada. En simultáneo, las dudas sobre la seguridad y eficacia de las vacunas estructuraron argumentos de reticencia vacunal, que entendemos como parte de prácticas extendidas, asociadas con las desconfianzas hacia las instituciones y reinterpretaciones del conocimiento científico y del cuidado.; In the face of declining vaccination coverage and the dissemination of health-related information, conversations in the public/mediatic digital sphere constitute a relevant study area for the field of health communication. Through a qualitative study based on the analysis of government publications, digital press, and social media, we characterize the public conversation on vaccines – in terms of topics, moments, axes, and framings in Argentina during the 2020-2021 period – marked by the debate on covid-19 vaccines. The results show that public conversation focused on covid-19 vaccination, structured in two distinct moments (vaccine production and vaccination campaign), and under moral framings grounded in vaccination as a care practice and science as an authoritative voice. Simultaneously, doubts about the safety and efficacy of vaccines shaped arguments of vaccine hesitancy, which we understand as part of extended practices associated with distrust towards institutions and reinterpretations of scientific knowledge and care.

An animal model for the study of binge-like eating episodes preceded by frustration events in females and non-food deprived animals Serafini, Matías; Cuenya, Lucas Introduction: Previous data from our laboratory show that frustration events could function as an important factor in the etiology and maintenance of the binge-like eating episodes. However, in previous experiments, male Wistar rats deprived of food were used. This reduced the external validity of the phenomenon as an animal model of binge-eating episodes since they are more prevalent in women and can occur without prior energy deficit. Objective: To explore the presence of increased intake after a previous frustration event in two new experimental conditions: male rats without food deprivation (experiment 1) and female rats with food deprivation at 83% of their ad libitum weight (experiment 2). Method: The animals had access to a 32% sweetened solution during five daily trials of five minutes each. During the trials 6, 8 and 10, half of the animals received the reinforcer normally, and the other half after a delay of 10 min. In the trials 7, 9 and 11 all animals received the reward without prior delay. Results: The model was replicated in the two experiments. Discussion: These data generalize our previous observations to two novel conditions, one sexual and the other motivational, which results in an increase in its external validity.

An animal model for the study of binge-like eating episodes preceded by frustration events in females and non-food deprived animals Serafini, Matías; Cuenya, Lucas Introduction: Previous data from our laboratory show that frustration events could function as an important factor in the etiology and maintenance of the binge-like eating episodes. However, in previous experiments, male Wistar rats deprived of food were used. This reduced the external validity of the phenomenon as an animal model of binge-eating episodes since they are more prevalent in women and can occur without prior energy deficit. Objective: To explore the presence of increased intake after a previous frustration event in two new experimental conditions: male rats without food deprivation (experiment 1) and female rats with food deprivation at 83% of their ad libitum weight (experiment 2). Method: The animals had access to a 32% sweetened solution during five daily trials of five minutes each. During the trials 6, 8 and 10, half of the animals received the reinforcer normally, and the other half after a delay of 10 min. In the trials 7, 9 and 11 all animals received the reward without prior delay. Results: The model was replicated in the two experiments. Discussion: These data generalize our previous observations to two novel conditions, one sexual and the other motivational, which results in an increase in its external validity.

Evaluating the climatic suitability of Engytatus passionarius Minghetti et al. (Heteroptera, Miridae) as a biological control agent of the invasive stinking passion flower Passiflora foetida L. in Australia through ecological niche models Minghetti, Eugenia; Dellapé, Pablo Matías; Maestro, Mariano; Montemayor Borsinger, Sara Itzel Passiflora foetida is a climbing vine, native to the Neotropical Region that is causing major economic and ecological damage in Australia, where it is rapidly spreading. Traditional control options, such as cutting, manual uprooting, and herbicide applications are only effective for local management. Currently, the plant bug Engytatus passionarius is the most promising biological control agent. Specificity tests performed in its native range in Argentina suggest it is highly specific to the plant, and it has not been observed in the field associated with other plants. As climate determines the establishment of insects, knowing if the environmental conditions suit their requirements is key to introducing a species in a region. Also, an overlap between the climatic niches of species is an indicator of similar requirements. To explore the possibilities of a successful establishment of E. passionarius in Australia, ecological niche models (ENM) were built for the plant bug and for the vine and their overlap was measured. The ENM projected to Australia recognized suitable environmental conditions for the establishment of E. passionarius in several regions where P. foetida is present, both for current and future scenarios. Moreover, the niche of the plant bug is almost completely overlapped with that of the vine. All the aforementioned evidence seems to indicate that E. passionarius has a good chance to become an effective biological control agent of P. foetida.

Impact of vineyards on habitat's thermal conditions and functional traits of a lizard in the central Monte Desert, Argentina Méndez Osorio, Yamila Gimena; Gómez Alés, Carlos Rodrigo; Avellá Machado, Elín Araceli; Acosta, Juan Carlos Vegetation modulates the spatial arrangement of microclimates and changes in land cover due to agriculturalactivities alter thermal landscapes. Lizard body temperature is strongly influenced by the thermal quality of theenvironment at the microhabitat level and land management for agriculture in arid environments can reduce thethermal quality of a species’ habitat. Our objective was to evaluate if there are variations in the thermal biologyand thermal quality of the habitat in Liolaemus darwinii, at a site modified by vineyards and in a natural habitat inthe central Monte Desert, Argentina. Our findings indicate that vineyard-induced habitat modifications have animpact on operative temperatures and the thermal quality of the environment. This variability, in turn, is likelyto bring about changes in locomotor performance traits and thermoregulatory strategies of Liolaemus darwinii.Our conclusion highlights the efficient thermoregulatory capabilities of L. darwinii across both sites. Furthermore,we propose that the analysis of changes in thermal landscapes, habitat thermal quality, and their correlation withorganisms’ thermal traits can serve as a practical tool for assessing the impact of agricultural activities in aridenvironments. Additionally, it aids in the development of conservation strategies that promote the preservationof neighboring native vegetation.

Genetic study in Argentinian patients with clinical Long QT Syndrome diagnosis Dionisio, Leonardo Raul; Stupniki, Sofia; Aztiria, Eugenio Manuel; Rias, Ezequiel Ignacio; Dye, Leandro; Onetto, Leonardo; Gregorietti, Franco; Keegan, Roberto; Spitzmaul, Guillermo Federico Long QT Syndrome (LQTS) is a genetic cardiac condition in which varying degrees of severity and treatment response. Three are primarily affected by mutations that cause cardiac ion channel dysfunction. In Argentina, most of the LQTS diagnoses are made by clinical examination and ECG analysis. In this study, we evaluated a group of individuals to correlate their clinical diagnosis of LQTS with genetic variations. Using gDNA isolation, PCR, and exome sequencing, we screened the coding sequences of the KCNQ1, KCNH2, and SCN5A genes. We identified several changes in these genes, most of them previously described in the literature, but also a novel variation. We found an alteration in the sequence of KCNQ1 exon 16 which did not allow us to amplify it. This is the first analysis of genetic variations in LQTS in Argentina conducted by a national research laboratory. The combination of the detected variations may explain the prolongation of the QT interval observed in the ECG of some of the individuals and may help to improve the treatment making it more rational as well as provide genetic counselling to first-degree relatives

Comportamiento de larvas de Aedes albifasciatus parasitadas por el Nematodo Strelkovimermis spiculatus Los datos corresponden al comportamiento de larvas de Aedes albifasciatus en relación con el tiempo de dormancia de los huevos de los cuales eclosionaron y con el parasitismo producido por Strelkovimermis spiculatus. El registro de los datos se realizó en condiciones de laboratorio utilizando el programa Ethology 2.25 (Ottoni 2000).

Non-native barnacle accelerates the recovery from disturbance of intertidal mussel beds Soria, Sabrina Andrea; Gutierrez, Jorge Luis Ceferino; Palomo, Maria Gabriela The barnacle Balanus glandula is a non-native species inhabiting Argentinian rocky shores. The native mussel Brachidontes rodriguezii forms extensive beds in the mid-intertidal zone of these shores, generating a physical structure that determines the diversity of the assemblage. Yet, this native foundation species is prone to mortality due to disturbances associated with extreme climatic events. The aim of this study was to experimentally investigate the role of early-colonizing, non-native B. glandula in the succession process and the recovery of mussel beds following disturbance. Experimental plots were demarcated in the mussel bed and initially cleared of mussels, to produce exposed rock surfaces similar to those that form after a disturbance event. Half of these plots were kept barnacle-free throughout the experiment by removing all recruiting B. glandula, whereas all recruits were allowed to develop in the remaining plots. Our results showed that mussel cover at the end of the experiment was higher in the plots with barnacles. The plots with and without barnacles followed different successional trajectories, with increasing limpet densities and reduced cover of crustose algae in the presence of barnacles during early successional stages. The results indicate that the presence of B. glandula at the early stages of succession can alter successional dynamics and facilitate the recovery of mussel bed cover after disturbance events. More broadly, this study also shows that non-native species, although frequently considered a ‘nuisance’, can accelerate the recovery of foundation species that characterize entire communities and sustain the greatest share of their diversity.

Comportamiento de larvas de Aedes albifasciatus parasitadas por el Nematodo Strelkovimermis spiculatus Comportamiento de larvas de Aedes albifasciatus provenientes de huevos de diferentes edades, parasitadas por Strelkovimermis spiculatus.

El Boletín de la Biblioteca Pública de la Provincia de Buenos Aires: un instrumento estratégico de gestión y exhibición (1899-1905); The Bulletin of the Public Library of the Province of Buenos Aires: a strategic management and exhibition instrument (1899-1905) Dorta, Ruth Ayelén Se elabora una caracterización del Boletín de la Biblioteca Pública de la Provincia de Buenos Aires, editado entre 1899 y 1905 por Luis Ricardo Fors en el marco de sus funciones como director de la Biblioteca situada en La Plata. Se parte de una breve inscripción del órgano periódico en el campo revisteril decimonónico para, luego, poner la mirada sobre los aspectos materiales y de contenido que configuraron su identidad. A modo de conclusión, se sostiene que el Boletín se constituyó como un hito en la historia institucional del espacio bibliotecario y en la historia de la bibliotecología argentina como disciplina en emergencia. En paralelo, se argumenta que Fors hizo un empleo estratégico de éste dispositivo, tanto en términos institucionales como personales.; A characterization is made of the Bulletin of the Public Library of the Province of Buenos Aires, edited between 1899 and 1905 by Luis Ricardo Fors as director of the Library located in La Plata. It starts from a brief inscription of the periodical organ in the field of magazines from the late 19th century and early 20th century to then look at the material and content aspects that shaped its identity. In conclusion, it is argued that the Bulletin was established as a milestone in the institutional history of the Library and in the Argentine library history science as an emerging discipline. In parallel, it is argued that Fors made strategic use of this device, both in institutional and personal terms.

Environmental benchmarks for the European cement industry Sambataro, Luciano; Bre, Facundo; Ukrainczyk, Neven; Koenders, Eduardus A. B. The urgent need to address climate change has pushed Europe to the forefront of environmental legislation initiatives, such as the Environment Action Program (EAP) within the European Green Deal and the disclosure of Environmental Product Declarations (EPDs) in the construction sector. The cement industry plays a vital role in this transition because it is one of the biggest contributors to greenhouse gas emissions worldwide. EPDs have managed to articulate the environmental information flow across different stakeholders, allowing them to incorporate sustainability design practices at the manufacturing, construction, and design levels. However, current EPDs are deterministically disclosed and lack benchmarks, hindering effective comparison and impeding sustainable material development. To address this challenge, the present research introduces a novel Life Cycle Assessment (LCA)-based probabilistic analysis to develop clinker and cement benchmarks. The proposed method incorporates data from industry reports, environmental databases, and EPDs, to generate the stochastic benchmarks. Moreover, a wide range of environmental performance indicators at a national level in Europe are covered, offering a holistic perspective beyond climate change. The results highlight the benefits of using country-specific environmental benchmarks, reducing the standard deviation of results by 2 to 7 times compared to background datasets. The reduction of clinker content proved to reduce 7 to 9 kg CO2eq/t for every 1% reduction in all countries. However, it also increased other indicators depending on the mineral component used as a replacement, underscoring the need for holistic analysis. The research also exposes discrepancies between EPDs and industry-related data, accentuating the need for stochastic information disclosure to enhance reliability and facilitate decision-making by stakeholders. Another significant contribution of this research is the development of an extensive open-access database, providing a reference for future developments regarding sustainable cement and concrete.

Crónicas de implementación: la política educativa viva; Chronicles of implementation: the live educational policy Alucin, Silvia Vanesa En este artículo construimos breves crónicas de implementación de políticas educativas que apuntan a la inclusión en el nivel medio. El trabajo de campo fue realizado, desde una perspectiva etnográfica, en tres escuelas secundarias de la ciudad de Rosario (Santa Fe), entre 2020 y 2023. En estos establecimientos rastreamos estrategias institucionales delimitadas en el camino de la implementación, la traducción, la apropiación de políticas estatales. Analizaremos tres mecanismos a través de los cuales fueron cobrando vida diferentes planes y programas. Éstos son la toma de posiciones al momento de implementar políticas de distribución y asistencia; los modos de ejercer las políticas de acompañamiento educativo y el aprovechamiento de los recursos que brindan las políticas. De este modo indagamos las diversas formas que toma lo estatal en lo escolar.; In this article we construct short chronicles of the implementation of educational policies aimed at inclusion at the secondary level. The fieldwork was conducted, from an ethnographic perspective, in three secondary schools in the city of Rosario (Santa Fe), between 2020 and 2023. In these establishments we tracked institutional strategies delimited in the route of implementation, translation, appropriation of state policies. We will analyze three mechanisms through which different plans and programs came to life. These are the positions taken at the time of implementing distribution and assistance policies; the ways of exercising educational support policies and the use of the resources provided by the policies. In this way, we investigate the different forms taken by the state in schools.

Border effects on the ground state of an ultrathin magnetic film model Horowitz, Claudio; Loscar, Ernesto Selim In the study of ultrathin magnetic films, one of the most simple and widely studied model is the two-dimensional Ising model with short-range ferromagnetic exchange and long-range antiferromagnetic dipolar interactions (ILRA model). In substrates with periodic boundary conditions, it is well known that the ground state of this system, depending on the strength parameter delta , is given by the antiferromagnetic, the irregular checkerboard and the striped states. In this work, we study the border effects on the ground state. We develop a systematic study on square substrates of size LxL with open boundary conditions focusing our attention on the range 0.35 < delta < 0.75. Our results show that, at intermediate values of delta, none of the configurations present on substrates with periodic boundary conditions correspond to the ground state of the system. Specifically, we find three new kinds of ground states for L<9, which are also our best candidates to be ground state in systems of sizes up to L=100. Also, by means of the same systematic study on a similar short-range model, we analyze which of these ground states is a consequence of the long-range character of the dipolar interactions in the ILRA model.