Paula Gonzalez | Universidad Nacional de La Plata (original) (raw)

Papers by Paula Gonzalez

The contribution of maize to the diet of pre-Hispanic populations that inhabited Mendoza province... more The contribution of maize to the diet of pre-Hispanic populations that inhabited Mendoza province, the southernmost limit of agriculture in America, has been largely debated. Recently, on the basis of δ13C data it was suggested that cacti may mimic the pattern of human isotopic values attributed to maize consumption in this region. These studies relied on a univariate qualitative approach not suitable for accurately identifying dietary contribution when multiple potential resources are available. Here, we analyzed δ13C and δ15N published data by using Bayesian mixing models to estimate the proportional contributions of different plants and animals to the protein component and total diet. The effect of different fractionation values on these estimations was also assessed. Our results pointed out the importance of C3 vegetables in the pre-Hispanic diet of these populations and only a small contribution of maize in the later Late Holocene sample from North Mendoza. Fractionation values had a significant effect on diet estimation. Overall, our study highlights the importance of obtaining fractionation values for local resources and increasing the diversity of isotopes analyzed for both the consumer and the potential resources to get a better understanding of diet variation in this region.

International Journal of Legal Medicine, 2008

As part of a more extensive investigation of skin wounding mechanisms, we studied wounds created ... more As part of a more extensive investigation of skin wounding mechanisms, we studied wounds created by five common screwdrivers (straight, star, square or Robertson, Posidriv and Phillips) on the shaven foreheads of 12 freshly slaughtered pigs. We fixed the different screwdriver heads to a 5-kg metal cylinder which was directed vertically onto each pig head by a droptube of 700 mm length. We examined skin lesions by photography and also by scanning electron microscopy (SEM). Our evaluation of differences in wound shape and size was based on geometric morphometric methods. Our results show that there are obvious morphological differences between the straight head and the other types. The straight-headed screwdriver penetrates the skin by a mode II crack which results in a compressed skin plug with bundles of collagen fibres forming skin tabs within the actual wound. The sharper-tipped screwdrivers wedge open the skin (mode I), with a clearly defined edge with no skin plugs. Geometric morphometric analysis indicates that shapes of skin wounds created by the five screwdriver types could be classified into three different groups. The straight head results in the most differentiated wound profile, with the Robertson or square and some specimens of star, and also the Posidriv and Phillips giving similar wound outlines. SEM evaluation of wounds created by a new and worn straight-head screwdrivers shows that the outline of the worn screwdriver head is reflected in the shape of the wound it created.

En los últimos años se observa una tendencia creciente hacia el desarrollo de prácticas que garan... more En los últimos años se observa una tendencia creciente hacia el desarrollo de prácticas que garanticen un acceso libre al conocimiento científico producido a través del aporte de fondos públicos. Este movimiento conocido como open access está ampliamente desarrollado en algunas disciplinas como la genética y la biología molecular, sin embargo en la antropología biológica su discusión es incipiente. El presente trabajo tiene por objetivo presentar algunas de las ventajas de esta política, tanto para los científicos como para la comunidad en general, y discutir un conjunto de aspectos prácticos que requieren ser considerados para la implementación del libre acceso a los datos (data sharing) en el seno de la antropología biológica. Particularmente, se discute acerca de la forma de obtención, almacenamiento, publicación y posterior uso de datos morfométricos en formato numérico, coordenadas 2 y 3D e imágenes digitales. Finalmente, se delinea una agenda de trabajo a fin de promover la discusión sobre el data sharing en nuestro pais.

…, Jan 1, 2010

Skip to Main Content. Due to scheduled maintenance access to the Wiley Online Library may be disr... more Skip to Main Content. Due to scheduled maintenance access to the Wiley Online Library may be disrupted as follows: Monday, 6 September - New York 0400 EDT to 0500 EDT; London 0900 BST to 1000 BST; Singapore 1600 to 1700. ...

Evolutionary Biology. In Press

The study of shape changes in morphology has seen a significant renovation in the last 20 years, ... more The study of shape changes in morphology has seen a significant renovation in the last 20 years, particularly as a consequence of the development of geometric morphometric methods based on Cartesian coordinates of points. In order to extract information about shape differences when Cartesian coordinates are used, it is necessary to establish a common reference frame or system for all specimens to be compared. Therefore, a central issue in coordinate-based methods is which criterion should be used to align these configurations of points, since shape differences highly depend on those alignments. This is usually accomplished by aligning the configurations in a way that the sum of squared distances between coordinates of homologous points (landmarks) is minimized: the least-squares superimposition method. However, it is widely recognized that this method has some limitations when shape differences are not homogeneous across landmarks. Here we present an integrated approach for the resistant shape comparison of 3D landmark sets. It includes a new ordinary resistant Procrustes superimposition and its corresponding generalized resistant Procrustes version. In addition, they are combined with existing resistant multivariate statistical techniques for depicting the results. We demonstrate, by using both simulated and real datasets, that resistant Procrustes better detects and measures localized shape variation whenever present in up to half but one of the landmarks. The resistant Procrustes results are highly concordant with a priori biological information, and might dramatically improve the quality of inferences on patterns of shape variation.

Revista del Museo de Antropologia

Over the last two decades there has been an increased interest in promoting the open access to sc... more Over the last two decades there has been an increased interest in promoting the open access to scientific databases, predominantly those obtained in the context of the publicly funded science system. The main objective of this contribution is to review the advantages of this policy for the scientists as well as the general public. We point out some issues regarding to data collection, storage and publication, which still remain to be solved in order to implement the policy of data sharing within biological anthropology. Particularly, we focus on traditional and geometric morphometric data, and the new technologies for gathering digital images in 2D and 3D. We finally outline a set of points that need to be addressed in order to promote the discussion about data sharing in Argentina.

Resumen: En los últimos años se observa una tendencia creciente hacia el desarrollo de prácticas que garanticen un acceso libre al conocimiento científico producido a través del aporte de fondos públicos. Este movimiento conocido como open access está ampliamente desarrollado en algunas disciplinas como la genética y la biología molecular, sin embargo en la antropología biológica su discusión es incipiente. El presente trabajo tiene por objetivo presentar algunas de las ventajas de esta política, tanto para los científicos como para la comunidad en general, y discutir un conjunto de aspectos prácticos que requieren ser considerados para la implementación del libre acceso a los datos (data sharing) en el seno de la antropología biológica. Particularmente, se discute acerca de la forma de obtención, almacenamiento, publicación y posterior uso de datos morfométricos en formato numérico, coordenadas 2 y 3D e imágenes digitales. Finalmente, se delinea una agenda de trabajo a fin de promover la discusión sobre el data sharing en nuestro pais.

Evolutionary Biology

The developmental processes that contribute to variation of morphological traits are the subject... more The developmental processes that contribute to
variation of morphological traits are the subject of considerable
interest when attempting to understand phenotypic
evolution. It is well demonstrated that most characteristics
of tooth pattern can be modified by tinkering conserved
signal pathways involved in dental development. This effect
can be evaluated by comparing developmental models with
naturally occurring variation within explicit phylogenetic
contexts. Here, we assess whether evolutionary changes in
lower molar (M) ratios among platyrrhines were channelled
by alterations in the balance of activators and inhibitors as
predicted by the inhibitory cascade (IC) model (Kavanagh
et al. in Nature 449:427–432, 2007). Ordinary linear
regression adjusted to M2/M1 versus M3/M1 ratios of 38
species of platyrrhines indicated that the slope and intercept
were significantly different from the IC model. Conversely,
when the phylogeny was incorporated into the regression
analyses (PGLS), variation in molar ratios did not differ
from the developmental model. PGLS also showed that
changes in molar proportions are not an allometric effect
associated with body size. Discrepancies between phylogenetically
corrected and non-corrected analyses are mainly
due to the departure of Callitrichines from the predicted
values. This subfamily displays agenesis of M3 with higher
than expected M2/M1 ratios, indicating that M3 fails to
develop even when the inhibition by M1 on the subsequent
molars is not increased. Our results show that evolution in
molar ratios is concordant with slight changes in the proportion
of activators and inhibitors that regulate molar
development; however, other processes are required to
account for variation in the number of teeth.

Evolution and Development (in press), Mar 1, 2013

Organism size is controlled by interactions between genetic and environmental factors mediated by... more Organism size is controlled by interactions between genetic and environmental factors mediated by hormones with systemic and local effects. As changes in size are usually not isometric, a considerable diversity in shape can be generated through modifications in the patterns of ontogenetic allometry. In this study we evaluated the role of timing and dose of growth hormone (GH) release on growth and correlated shape changes in craniofacial bones. Using a longitudinal study design, we analyzed GH deficient mice treated with GH supplementation commencing pre- and post-puberty. We obtained 3D in vivo micro-CT images of the skull between 21 and 60 days of age and used geometric morphometrics to analyze size and shape changes among control and GH deficient treated and non-treated mice. The variable levels of circulating GH altered the size and shape of the adult skull, and influenced the cranial base, vault, and face differently. While cranial base synchondroses and facial sutures were susceptible to either the direct or indirect effect of GH supplementation, its effect was negligible on the vault. Such different responses support the role of intrinsic growth trajectories of skeletal components in controlling the modifications induced by systemic factors. Contrary to the expected, the timing of GH treatment did not have an effect on catch-up growth. GH levels also altered the ontogenetic trajectories by inducing changes in their location and extension in the shape space, indicating that differences arose before 21 days and were further accentuated by a truncation of the ontogenetic trajectories in GHD groups.

American journal of …, Jan 1, 2010

Revista Argentina de Antropologia Biologica

El objetivo de este trabajo es desarrollar funciones discriminantes para estimar el sexo en pobla... more El objetivo de este trabajo es desarrollar funciones discriminantes para estimar el sexo en poblaciones sudamericanas a partir de variables métricas del fémur. Con este fin se seleccionaron tres muestras de poblaciones aborígenes procedentes de: a) Sur de Patagonia (n=61), b) Norte de Patagonia y Sur de Pampa (n=94) y c) NE Pampa y Entre Ríos (n=51). Sólo se incluyeron los individuos que presentaban estructuras diagnósticas de la pelvis que fueron
utilizadas para obtener una estimación confiable del sexo. Posteriormente, se relevaron nueve variables del fémur, cinco de las cuales (diámetro de la cabeza, longitud fisiológica, ancho epicondilar y diámetros antero-posterior y medio-lateral del centro de la diáfisis) fueron empleadas para generar funciones discriminantes a través del método stepwise forward. Estas funciones incorporaron diferentes combinaciones de las variables en las tres muestras. El sexo estimado con las funciones fue contrastado con su correspondiente, a partir de variables de la
pelvis a fin de establecer la exactitud de las mismas. Los porcentajes de asignaciones correctas calculados mediante el método de validación cruzada fueron elevados en las tres muestras, variando en promedio entre el 80% y el 94%. Por lo tanto, los resultados obtenidos indican que la técnica desarrollada proporciona un estándar específico para las poblaciones del sur de Sudamérica y constituye una herramienta confiable para la estimación del sexo en muestras procedentes
de las áreas analizadas.

American journal of …, Jan 1, 2007

American Journal of …, Jan 1, 2006