Buenos Aires Province Research Articles

Population Size, Non-Breeding Fraction, and Productivity in a Large Urban Population of Burrowing Parrots (Cyanoliseus patagonus)

Psittaciformes are one of the bird orders with the highest number of threatened species and the most marked declining population trends. At present, the lack of information on the population size, reproductive fraction, and productivity of most parrot populations makes it difficult to design effective conservation actions. In this study, we monitored a population of Burrowing Parrots (Cyanoliseus patagonus) breeding in urbanized habitats in the southwest of Buenos Aires province, Argentina. Every December and February from 2018 to 2023, we counted the individuals arriving at a single communal roost, located in the main park of Bahía Blanca city, which gathers all the parrots breeding in 18–22 colonies within a radius of 20 km. Censuses were conducted before (December) and immediately after the incorporation of juveniles into the flocks (February). Breeding pairs were also counted annually in the colonies, and the average annual productivity and the proportion of juveniles were estimated from surveys in pre-roosting and feeding areas in February. The non-breeding fraction approached half of the population with no statistically significant differences among years (range: 37–53%), and the breeding population showed little annual variation, with a minimum of 1363 and a maximum of 1612 breeding pairs. The proportion of juveniles in the flocks and the estimated productivity showed larger variations among breeding seasons. Our results add insight to the scarce information available on the breeding-to-non-breeding-population ratios in parrots, and birds in general, and show key breeding parameters for a species that is thriving well in urban habitats.

Cyonasua zettii sp. nov. (Procyonidae, Mammalia) from the Late Miocene of Central Argentina and a review of the fossil record of Cerro Azul Formation

ABSTRACT A detailed taxonomic study of all known fossil specimens assigned to Procyonidae from sediments of Cerro Azul Formation (early Huayquerian Stage/Age, Late Miocene) outcroping at La Pampa and Buenos Aires provinces (Argentina) is presented here. Our study led us to propose a new species, Cyonasua zettii sp. nov. coming from La Pampa Province. In addition another six specimens studied, coming from La Pampa and Buenos Aires provinces, are assigned to Cyonasua longirostris and four specimens are assigned to Cyonasua sp. because its fragmentary nature prevents a determination at species level. The specimens described here are among the oldest records for the Order Carnivora (Mammalia) in South America.

Quaternary Mammals from Central-Western Argentina in the Stratigraphic Context of Southern South America

This is an updated contribution to the Quaternary geology and paleontology from central-western Argentina, focused on San Luis Province. It is mostly based on unpublished data; only some fossils had previously been briefly mentioned in broader faunal contexts. The fossil-bearing sediments correspond to eolian and alluvial environments of moderate energy, dominated by sands and sandy silts. They overlie high-energy fluvial cycles and underlie edaphic horizons. They have a wide distribution, and several radiocarbon dates allow their regional correlation. Stratigraphic sequences with the precise origin of fossils allow for the improvement of lithostratigraphic and faunal correlations with the Pampean Region (central and east Argentina; La Pampa and Buenos Aires provinces), where Pleistocene assemblages are better known, but also with central-western (Cuyo Region), northwestern, and northeastern Argentina. Faunal remains correspond to large mammals, represented by xenarthrans (Cingulata and Tardigrada), macraucheniids (Litopterna), gomphotheres (Proboscidea), and equids (Perissodactyla), a typical Pleistocene mixture of native (xenarthrans and litopterns) and immigrant mammals.

Cinética de consumo de sustratos orgánicos de bacterias aisladas de la Laguna de Chascomus

Eight bacterial strains were isolated from Chascomús Pond (Buenos Aires Province) and their capacity to growth at low concentrations of glycolate and glucose, as a solé source of organic carbón was evaluated.Substrate affinities (Kt valúes) and other kinetic parameters were measured by Wright & Hobbie methodology with 14C-labelled glycollate and MC-labelled glucose as substrates. Four o f the eight puré culture studied followed Michaelis-Menten uptakekinetics giving good straight lines after the Lineweaver-Burke transfonnation.Vmax valúes o f natural popuiations and the experimental ones were similar for glycollate; for glucose the experimental valúes were a little higher. This suggest the possibility o f applying the experimental Kt valúes to natural popuiations as a way of evaluation o f the natural substrate concentration.

Prevalence of Intestinal Parasitoses in Dogs within a Vulnerable Area of Ensenada, Buenos Aires Province, Argentina

The potential role of dogs as reservoirs of zoonotic infections is one of the major public health problems. Water emergency areas are generally vulnerable zones with a lack of care from the owners who do not have the basic sanitary service conditions. Dogs often feed on waste detecting coprophagia of human faeces facilitated by the final disposal of excreta in open-air defecation. The objective of this research was to determine the presence of intestinal parasitoses in dogs from a sanitary risk area inhabited by a vulnerable human population. Dog faeces were collected by an enema with a soapy solution and processed by the Telemann’s sedimentation technique as well as the Sheather’s flotation procedure besides a direct examination. A number of 703 (79.3%) analyzed dog faeces were parasitized from a total of 886. Ancylostoma caninum (57%), Toxocara canis (24%) and Uncinaria stenocephala (21%) were the most frequent species. The specific richness in the dog population was 17 species. The highest parasitosis frequency was observed among male dogs and those under one-year aged for the total parasitized ones with T. canis, Cystoisospora canis, C. ohioensis, and Giardia spp. High prevalences found in dogs from the present study could indicate that both diagnosis and treatment are not enough to achieve sustainable changes in vulnerable areas. Actions addressed to the environmental factor are essentials in order to avoid reinfections.

Prevalence and Genetic Diversity of a Microsporidian Parasite in the Black Imported Fire Ant and Its Social Parasitic Ant (Formicidae: Myrmicinae: Solenopsis) in Buenos Aires Province, Argentina.

Microsporidia are natural pathogens of arthropods and have been used as biological control against insect pests. In the United States, efforts to control the invasive Red Imported Fire Ant, Solenopsis invicta, and Black Imported Fire Ant, Solenopsis richteri, have included the use of the microsporidium, Kneallhazia solenopsae. However, there is limited information about the genetic differences among the microsporidian variants found in S. invicta and in S. richteri. In this study, we assessed the prevalence and genetic diversity of K. solenopsae in native populations of S. richteri in Argentina (South America). Additionally, we examined the social parasitic ant, Solenopsis daguerrei, which is found in some S. richteri nests, for the presence of this microsporidium. The survey of 219 S. richteri nests revealed K. solenopsae infections in all five sites analyzed, with 28 colonies (12.8%) positive for the microsporidium. Among the 180 S. daguerrei individuals collected, seven ants (3.9%) from three sites tested positive for K. solenopsae. Phylogenetic analyses of the microsporidian variants present in S. richteri and S. daguerrei based on partial small subunit ribosomal gene sequences (SSU rRNA) showed that both ant species shared the same variant, which is different from the ones found in S. invicta. Further studies are needed to determine the pathogenicity of genetically different K. solenopsae variants among Solenopsis species.

Description of a new genus of Escherbothriidae (Cestoda: Rhinebothriidea) in species of Sympterygia (Rajiformes: Arhynchobatidae) from South America based on morphological and molecular evidence, with an amended diagnosis of the family

Ivanovcestus yakiae gen. et sp. nov. was collected from specimens of the batoid Sympterygia bonapartii from waters off Río Negro and Buenos Aires Provinces, in the Argentine Sea. Ivanovcestus gen. nov. is assigned to the Rhinebothriidea for their possession of facially loculated bothridia borne on stalks and a cirrus covered by spinitriches. The new genus is unique in the arrangement of loculi and septa on the distal bothridial surface. The molecular analysis based on 18S and 28S rDNA of two specimens of the new species identified Ivanovcestus gen. nov. as a member of the family Escherbothriidae, with our study representing the first record of this family in the Argentine Sea. The proposed new genus requires a new amended diagnosis for the Escherbothriidae, to include a new pattern of loculi and septa for the distal bothridial surface, as well as a new host. In addition, the present study proposes to transfer two species of Rhinebothrium, originally described parasitizing the skate Sympterygia lima in the Chilean Sea (i.e., Rhinebothrium chilensis and Rhinebothrium leiblei), to Ivanovcestus gen. nov. Examination of the original descriptions and type material revealed several morphological characters that justify the relocation of both species to the new genus.

Morphological and molecular characterization of Geraldius galapagoensis (Nematoda: Chambersiellidae) associated with lichens in Argentina

Lichens are symbiotic organisms, usually composed of a fungal partner, the mycobiont, and one or more photosynthetic partners, the photobiont, which is most often either a green alga or a cyanobacterium, that harbor a diverse community of invertebrates such as rotifers, tardigrades, mites, springtails, crustaceans, and nematodes. In this work, we isolated the nematode Geraldius galapagoensis (Chambersiellidae) associated with the lichen Hyperphyscia syncolla (Physciaceae) in a region of Buenos Aires Province, Argentina. This species was discovered in a tropical forest of Ecuador and is characterized mainly by a head offset by a constriction from the rest of the body, a esophagus with a cylindrical pharyngeal corpus without a median bulb, a narrow isthmus and an oval basal pharyngeal bulb with strong transverse/butterfly valve apparatus, a tail curved ventrally, ending in dorsally hooked end; the male with seven pairs of latero-ventral pre-anal papillae and three pairs of post-anal in the following positions: one pair latero-ventral and two pairs dorso-lateral and two slightly curved spicules with asymmetric manubrium with an anterior extension. The comparison of the morphometrics of our G. galapagoensis male with that of the original description shows that the body length is shorter, as are the distance of the excretory pore to the anterior end and the tail. On the other hand, the distance from the anterior end to the nerve ring and the esophagus length are greater. The head width, body diameter and spicule length are quite similar. We provide a morphological and morphometrical characterization of a G. galapagoensis second isolate and the first world report of molecular sequences belonging to this species.

Social mycorrhiza: The social infrastructure of agroecological farming economies

ABSTRACT Alternative agriculture (e.g. agroecology and organics) aims to address global environmental and social problems: goals that hinge on alternative farms’ economic viability. Viability depends on farmers accessing key resources (e.g. land), typically through markets, but also through social relationships. In this article, I offer a theory of how agroecological farmers’ social infrastructure can enable resource access. ‘Social mycorrhiza’ uses ecological mycorrhiza as a metaphor to conceptualize how individuals with simultaneous market interests and movement-based values (like alternative farmers) create social networks that facilitate resource access, in circumstances where they trust each other will act according to both their economic interests and their social and environmental values, over time. Social mycorrhiza highlights cooptation – when social and environmental values are sacrificed for economic interests – and burnout – when economic viability is sacrificed forsocial and environmental values. I illustrate social mycorrhiza using a case study of alternative (organic and agroecological) farmers in Buenos Aires Province, Argentina. In short, social mycorrhiza describes the social relational infrastructure of agroecological farming economies.

Capture of wild juveniles, growth and spawning of the southwestern Atlantic wreckfish (Polyprion americanus) in Argentina

Wreckfish (Polyprion americanus) is a marine fish of great interest as a new aquaculture species due to its easy adaptation to farming conditions, rapid growth and market price. In the Southwestern Atlantic Ocean, the species forms a genetic stock different from that of the Northern Hemisphere and also to populations of the South Pacific. This study presents the research conducted in Argentina from 2011 to 2020 on the development of a wreckfish broodstock from juvenile specimens. Wreckfish (n = 21) were caught with fishing rods at depth between 18 and 75 m depth, off the coast of Buenos Aires Province, Argentina (37°30′S - 39°00′S). All fish suffered barotrauma, but specimens captured at a depth < 45 m and whose swim bladders were deflated by puncture had a survival rate > 90%. Juvenile wreckfish (n = 12) with an initial body weight of 2–3 kg were kept in a recirculating aquaculture system (RAS) and fed local fish for 36 months. During this on-growing stage, a natural photoperiod regime with reduced light intensity was accompanied by seasonal variations in the RAS's thermal regime (14–19 °C). From then on, a maturity and reproductive protocol was implemented, where the temperature was lowered (12–17 °C) and the diet was complemented with a formulated semi-moist feed. Juvenile wreckfish grew fast, gaining about 2.5 kg in 11 months with a specific growth rate (SGRBW) of 0.2% day−1 and reaching 10–12 kg in 36 months. There was no significant difference in growth performance between sex groups during the on-growing stage. However, from months 36 to 57, the SGRBW of females (0.058 ± 0.008% day−1) was significantly higher than males (0.035 ± 0.005% day−1). After 67 months in captivity, the first natural spawning was achieved in a communal tank with a sex ratio 4 females: 6 males. Two consecutive spawning seasons were analysed, which showed a large daily variation in total number of eggs, percentage of floating eggs (potentially viable eggs) and spawning intervals. A marked improvement in spawning performance was observed from one season to the next. In the first season, a total production of 5.21 million eggs was reached, of which only about 2.7% were floating, while in the second season the values increased to 13.23 million eggs and 32.6%, respectively. We have successfully developed a broodstock of wreckfish capable of achieving natural spawning. Further research is needed to obtain reliable spawning and large production of high-quality eggs.

Estimating cumulative evapotranspiration using superconducting gravimeter data: a study in Buenos Aires Province, Argentina

ABSTRACT A new method for estimating cumulative evapotranspiration using superconducting gravimeter data is presented. Evapotranspiration is computed from the classical water balance equation using precipitation data, estimated runoff, and water storage assessed from temporal variations of gravity. The gravity-based methodology is applied to a study site located at the Argentinian–German Geodetic Observatory (AGGO) in the flatland area of Buenos Aires Province (Argentina), which houses the only superconducting gravimeter in South America. For the period from April 2017 to May 2018, the cumulative evapotranspiration is estimated at 710.7 ± 25.7 mm. Evapotranspiration values are successfully compared with estimates provided by three methods, based on the water balance equation using soil moisture data, the numerical modelling of water flow in the unsaturated zone and the MODIS product (MOD16A2). The analysis of evapotranspiration also allows us to identify a period of soil water stress which is validated by soil moisture measurements.

Temporal variation of the microplastic concentration in a stream that receives discharge from wastewater treatment plants

The temporal variation of the microplastic concentration was studied in the Langueyú stream, which is located in the department of Tandil, in the southeast of the Buenos Aires province in Argentina. This stream receives discharge from the wastewater treatment plants from a medium-sized city. A quantitative analysis of the microplastic concentration was carried out in different samplings, corresponding to different seasons. The study focused on the most contaminated point, located after the discharge of effluents from plants. Higher concentrations of MPs were found in winter (dry season), having approximately 6 times the concentrations found in summer and autumn (wet seasons). However, these differences would not be a direct consequence of the amount precipitation, but rather would be associated with a seasonal variation of human activities, mainly with respect to the type of clothing used in the cold season. The microfibers correspond to around 60–90% of microplastics found. The discharge from the plants causes changes in the parameters of the stream water, such as high electrical conductivity values, and also provide metallic contaminants such as Ca, Zn, and in smaller amounts Pb, Fe, Ni and Cu, which were found adhered to the microplastics and remain in the stream water in high quantities 3 km after the study point. The microplastic concentration presents a linear empirical correlation with the conductivity, and it was found that conductivity measurements would serve as an indicator of the microplastic concentration in the system under study.

Diversity of nematodes associated with Heterodermia diademata: A case study in the Eco Área of Avellaneda, Buenos Aires, Argentina

Lichens represent a complex life form characterized by a symbiotic partnership between at least two organisms: a fungus and an alga. In this unique relationship, the fungus offers a protective habitat for the alga, which, in turn, harnesses energy from sunshine, water and air to provide sustenance for the fungus. They fulfill ecological roles as a food source for many invertebrates and serve as the basal trophic level for a variety of animals, being considered micro-ecosystems which can host a rich and diverse biota. Nematodes are among the most widespread and abundant of all metazoans, inhabit moist interstitial environments in all habitats and are abundant in marine and freshwater benthic habitats and in the soil. They were also reported from accumulations of detritus in leaf axils, in the angles of tree branches and in mosses and lichens. In this case study, the trophic role and diversity of free-living nematodes associated with lichens were examined in an area of Buenos Aires province, Argentina, revealing seven genera of nematodes linked to Heterodermia diademata, representing all trophic levels of free-living nematodes: bacteriophages (Plectus and Acrobeles), fungivores (Aphelenchus), herbivores (Helicotylenchus), omnivores (Eudorylaimus and Mesodorylaimus) and a predator (Prionchulus).

Coping with inflation: Social perceptions and ordinary measures of price increases in contemporary Argentina

Since the COVID-19 pandemic, in a significant part of the world, the cost of living has once again become a central issue in the agenda of both governments and populations. However, in some countries, inflation has been a distinctive feature of the economy for more than a decade, which the pandemic has only exacerbated. Argentina is one of these countries. Based on a 4-year qualitative investigation carried out among low- and middle-income households in a mid-sized city in Buenos Aires province and complemented by observations made among senior households in the same province during the pandemic, this article seeks two purposes: on one hand, to analyze how price rise appears in people’s concerns when we focus on domestic economies and, on the other, to account for the ways of measuring inflation and evaluating its impacts on such economies. The document intends to contribute to the construction of a perspective on inflation that is attentive to how people act and think about the economy in their everyday lives.

3D model related to the publication: On Roth's "human fossil" from Baradero, Buenos Aires Province, Argentina: morphological and genetic analysis

3D model related to the publication: On Roth's "human fossil" from Baradero, Buenos Aires Province, Argentina: morphological and genetic analysis

On Roth’s “human fossil” from Baradero, Buenos Aires Province, Argentina: morphological and genetic analysis

The “human fossil” from Baradero, Buenos Aires Province, Argentina, is a collection of skeleton parts first recovered by the paleontologist Santiago Roth and further studied by the anthropologist Rudolf Martin. By the end of the nineteenth century and beginning of the twentieth century it was considered one of the oldest human skeletons from South America's southern cone. Here, we present the results of an interdisciplinary approach to study and contextualize the ancient individual remains. We discuss the context of the finding by first compiling the available evidence associated with the historical information and any previous scientific publications on this individual. Then, we conducted an osteobiographical assessment, by which we evaluated the sex, age, and overall preservation of the skeleton based on morphological features. To obtain a 3D virtual reconstruction of the skull, we performed high resolution CT-scans on selected skull fragments and the mandible. This was followed by the extraction of bone tissue and tooth samples for radiocarbon and genetic analyses, which brought only limited results due to poor preservation and possible contamination. We estimate that the individual from Baradero is a middle-aged adult male. We conclude that the revision of foundational collections with current methodological tools brings new insights and clarifies long held assumptions on the significance of samples that were recovered when archaeology was not yet professionalized.

1741P Are physicians aware of lung cancer screening benefits and the importance of implementing this? Data from two public hospitals in Buenos Aires province, Argentina

1741P Are physicians aware of lung cancer screening benefits and the importance of implementing this? Data from two public hospitals in Buenos Aires province, Argentina

Animal performance, carcass characteristics and beef quality of steers fed with a whole oat or maize grain-based diet

Aim of study: We evaluated the use of oat grain as an alternative source of energy to maize grain in high energy finishing diets. Maize crop production in arid and semi-arid areas is poor or non-existent. Thus, small grains such as oats have become an alternative in high energy rations due to their versatility and ease of cultivation. Area of study: Semiarid region of Buenos Aires province, Argentina Material and methods: Sixteen Angus steers were randomly assigned to two dietary treatments based on whole oats grain (OD) or whole maize grain (MD) for 61 days. Diets were formulated iso-nitrogenous and iso-energetic. Animal performance, carcass attributes and beef quality traits were evaluated. Longissimus thoracis steaks were wet-aged at 4°C for either 4 or 14 days. Main results: Similar results were found between OD and MD for the variables of performance, carcass evaluation and water retention in fresh meat. No interactions between diet and ageing period were found for any of the variables evaluated. The MD beef was lighter and had a redder appearance than the OD beef. The 4 days-aged beef showed higher values of L*, a* and b* and was more saturated than the 14 days-aged beef. However, the perception of beef colour by the human eye, evaluated through the CIEDE2000 metric, showed no differences among diets and ageing periods. Research highlights: Oat grain could be used in replacement of maize grain as an energy source in fattening rations of beef cattle, obtaining similar animal performance and meat quality.

Treatment and effectiveness of scabies in first cycle with permethrin 5 % in pediatric population

Introduction: the goals of treatment are eradication of the mites from the infected individual, prevention of spread of scabies to other individuals, relief of associated pruritus, and recognition and treatment of complications. Treatment generally includes everyone in the household, even if they have no symptoms: symptoms can take 4-6 weeks to develop after a person is infested. Scabies is most commonly treated with 5 % permethrin dermal cream. Objectives: to describe the factors associated with response to treatment and effectiveness of a first course of 5 % permethrin in a pediatric population with scabies. Material and methods: an observational, descriptive, cross-sectional, retrospective, retrospective study will be carried out through the study of clinical records from a primary health care center in Avellaneda, Buenos Aires Province, Argentina. The study period will include records from January 2020 to September 2022. The study population will be pediatric patients receiving care at the center and diagnosed with scabies.

Assessment of Landsat-8 and Sentinel-2 Water Indices: A Case Study in the Southwest of the Buenos Aires Province (Argentina).

The accuracy assessment of three different Normalized Difference Water indices (NDWIs) was performed in La Salada, a typical lake in the Pampean region. Data were gathered during April 2019, a period in which floods occurred in a large area in the Southwest of the Buenos Aires Province (Argentina). The accuracy of the estimations using spaceborne medium-resolution multi-spectral imaging and the reliability of three NDWIs to highlight shallow water features in satellite images were evaluated using a high-resolution airbone imagery as ground truth. We show that these indices computed using Landsat-8 and Sentinel-2 imagery are only loosely correlated to the actual flooded area in shallow waters. Indeed, NDWI values vary significantly depending on the satellite mission used and the type of index computed.