361 research outputs found
No bird database is perfect: citizen science and professional datasets contain different and complementary biodiversity Information
Citizen science has become a powerful tool for collecting big data on biodiversity. However, concerns have been raised about potential biases in these new datasets. We aimed to test whether citizen science bird databases have more biases than professional scientific databases. Our hypotheses were 1) citizen science databases will have more data on “easy to spot” species, that are widely distributed and have large body sizes; whereas 2) professional databases will have more endangered species and species of special interest for research. We analysed six Spanish bird databases: three professional, two citizen science and one mixed database. Our results show that, in general, occurrences in citizen science databases are better explained by the studied variables than professional databases, but no clear differences were found when analysed individually. Both citizen science and professional databases contain invaluable information on biodiversity but every database comes with a particular history and its stored data is the result of years of field sampling with heterogeneous goals, sampling methods and sampling effort. Consequently, raw observations should not be used directly as an ideal survey of the distribution or abundance of birds. We need to uncover these biases and develop new methods to properly incorporate the extensive and heterogeneous biodiversity data that is readily available to research. Galván, S., Barrientos, R. & Varela, S. (2022). No bird database is perfect: citizen science and professional datasets contain different and complementary biodiversity information. Citizen science has become a powerful tool for collecting big data on biodiversity. However, concerns have been raised about potential biases in these new datasets. We aimed to test whether citizen science bird databases have more biases than professional scientific databases. Our hypotheses were 1) citizen science databases will have more data on “easy to spot” species, that are widely distributed and have large body sizes; whereas 2) professional databases will have more endangered species and species of special interest for research. We analysed six Spanish bird databases: three professional, two citizen science and one mixed database. Our results show that, in general, occurrences in citizen science databases are better explained by the studied variables than professional databases, but no clear differences were found when analysed individually. Both citizen science and professional databases contain invaluable information on biodiversity but every database comes with a particular history and its stored data is the result of years of field sampling with heterogeneous goals, sampling methods and sampling effort. Consequently, raw observations should not be used directly as an ideal survey of the distribution or abundance of birds. We need to uncover these biases and develop new methods to properly incorporate the extensive and heterogeneous biodiversity data that is readily available to research. Galván, S., Barrientos, R. & Varela, S. (2022). No bird database is perfect: citizen science and professional datasets contain different and complementary biodiversity information. Ardeola, 69: 97-114La ciencia ciudadana se ha convertido en una poderosa herramienta para recopilar datos sobre biodiversidad. Sin embargo, a pesar de su disponibilidad para ser utilizados en investigaciones
científicas, sus posibles sesgos se encuentran bajo continuo debate. Por ello, en este trabajo pretendemos comprobar si estas bases de datos sobre avifauna de España presentan mayores sesgos que
aquellas científico-profesionales. Nuestras hipótesis son: 1) las bases de datos ciudadanas recogerán un mayor número de aves “fáciles de detectar” (ampliamente distribuidas y con mayores tamaños corporales), mientras que 2) las bases de datos profesionales recogerán preferentemente especies en peligro de extinción o con algún interés científico específico. Para comprobarlo, analizamos seis bases de
datos: tres profesionales, dos ciudadanas y una mixta. Nuestros resultados mostraron que, en general, las variables estudiadas explican mejor las observaciones de las bases de datos ciudadanas en comparación con aquellas de las bases de datos profesionales, aunque no se encontraron diferencias claras
cuando se analizaron individualmente. Así, tanto las bases de datos ciudadanas como las profesionales poseen una información muy valiosa sobre biodiversidad, aunque cada una de ellas posee una historia
particular y su información es el resultado de años de muestreo con objetivos, métodos y esfuerzos heterogéneos. En consecuencia, sus observaciones no deben utilizarse directamente como un reflejo
ideal de la distribución o la abundancia de estas aves. Así, es necesario detectar estos sesgos y desarrollar nuevos métodos para incorporar esta gran cantidad de datos sobre biodiversidad en futuras investigaciones. Galván, S., Barrientos, R. y Varela, S. (2022). Las bases de datos de ciencia ciudadana y profesionales poseen información diferente y complementaria sobre la avifauna. Ardeola, 69: 97-11
A robust University-NGO partnership: Analysing school efficiencies in Bolivia with community-based management techniques
Community-based management research is a collaborative effort between management, academics and communities in need with the specific goal of achieving social change to foster social justice. Because it is designed to promote and validate joint methods of discovery and community-based sources of knowledge, community-based management research has several unique characteristics, which may affect its execution. This article describes the process of a community-based management research project which is descriptive in nature and uses quantitative techniques to examine school efficiencies in low-income communities in a developing country – Bolivia. The article describes the partnership between a US-based university and a Bolivian not-for-profit organisation, the research context and the history of the research project, including its various phases. It focuses on the (yet unpublished) process of the community-based research as opposed to its content (which has been published elsewhere). The article also makes the case that the robust partnership between the US-based university and the Bolivian NGO has been a determining factor in achieving positive results. Strengths and limitations are examined in the hope that the experience may be helpful to others conducting descriptive quantitative management research using community-engaged frameworks in cross-cultural settings.
Keywords: international partnership, community-engaged scholarship, education efficiency, multicultural low-income education
Modelado de Cadenas Cinemáticas mediante Matrices de Desplazamiento. Una alternativa al método de Denavit-Hartenberg
En este trabajo se presenta un método para el modelado de cadenas cinemáticas de robots que salva las dificultades asociadas a la elección de los sistemas de coordenadas y obtención de los parámetros de Denavit-Hartenberg. El método propuesto parte del conocimiento de la posición y orientación del extremo del robot en su configuración de reposo, para ir obteniendo en qué se transforman éstas tras los sucesivos movimientos de sus grados de libertad en secuencia descendente, desde el más alejado al más cercano a su base. Los movimientos son calculados en base a las Matrices de Desplazamiento, que permiten conocer en que se transforma un punto cuando éste es desplazado (trasladado o rotado) con respecto a un eje que no pasa por el origen. A diferencia del método de Denavit-Hartenberg, que precisa ubicar para cada eslabón el origen y las direcciones de los vectores directores de los sistemas de referencia asociados, el método basado en las Matrices de Desplazamiento precisa solo identificar el eje de cada articulación, lo que le hace más simple e intuitivo que aquel. La obtención de las Matrices de Desplazamiento y con ellas del Modelo Cinemático Directo a partir de los ejes de la articulación, puede hacerse mediante algunas simples operaciones, fácilmente programables
Actitudes y prácticas en estudiantes con dismenorrea de la escuela profesional de obstetricia de la universidad privada Antenor Orrego - 2019
Con el objetivo de determinar las actitudes y prácticas en estudiantes con
dismenorrea de la Escuela Profesional de Obstetricia de la Universidad Privada
Antenor Orrego-Trujillo 2019, se realizó la presente investigación, de tipo
observacional, diseño descriptivo simple, en una muestra de 84 alumnas
seleccionadas por muestreo aleatorio simple, a quienes se les aplicó una encuesta
sobre actitudes y prácticas; la encuesta fue validada mediante el juicio de expertos,
con una validez según el coeficiente V de Aiken, de 0.919, la confiabilidad a través
de una prueba piloto según el Alfa de Cronbach de = 0.863. La edad promedio de
las estudiantes encuestadas fue de 19.8 ± 2.5 años, el 65.5% procede de zona
urbana; el I ciclo predominó en un 32.1%; la menarquia de las estudiantes fue en
un promedio de edad de 12.2 ±1.2 años. Los tipos de actitudes de las estudiantes
con dismenorrea fueron cognitivas negativas 84.5%, afectivas negativas 70.2%;
conductuales negativas 57.1% y las actitudes generales predominó en un 70.2 %
de forma negativa; los tipos de las prácticas fueron 86.9% inadecuadas y 13.1%
adecuadas; de acuerdo a las actitudes y prácticas por ciclo según las estudiantes
con dismenorrea se encontró que predomina un 87.5% de actitudes negativas
dentro del III ciclo y en un 100% de prácticas inadecuadas entre el IV y VI ciclo. Se
concluye que las actitudes en estudiantes con dismenorrea en general son
negativas en un 70.2% y las prácticas inadecuadas en un 86.9%.With the objective of determining the attitudes and practices of students with the
design of the Professional School of Obstetrics of the Universidad Privada Antenor
Orrego-Trujillo 2019, the present investigation was carried out, of observational
type, simple descriptive design, in a sample of 84 selected students By simple
random sampling, to whom a survey about attitudes and practices was applied; The
survey was validated by means of an expert judgment, with a duration according to
the Aiken V coefficient, of 0.919, the reliability through a pilot test according to the
Cronbach's Alpha of = 0.863. The average age of the students surveyed was 19.8
± 2.5 years, 65.5% comes from urban area; The cycle dominated by 32.1%; The
menarche of the students had an average age of 12.2 ± 1.2 years. The types of
attitudes of the students with dysmenorrhea were negative cognitive 84.5%,
affective negative 70.2%; negative behavior 57.1% and the general attitudes
predomínate in a 70.2% of negative form; The types of practices of students with
dysmenorrhea were 86.9% inadequate and 13.1% adequate; according to the
attitudes and practices of the cycle according to the students with dysmenor, 87.5%
of the negative attitudes in cycle III and in 100% of inadequate practices between
cycles IV and VI predominate. It is concluded that attitudes in students with
dysmenorrhea in general are negative in 70.2% and inappropriate practices in
86.9%.Tesi
Altered Glycosylation Contributes to Placental Dysfunction Upon Early Disruption of the NK Cell-DC Dynamics
Immune cells [e. g., dendritic cells (DC) and natural killer (NK) cells] are critical players during the pre-placentation stage for successful mammalian pregnancy. Proper placental and fetal development relies on balanced DC-NK cell interactions regulating immune cell homing, maternal vascular expansion, and trophoblast functions. Previously, we showed thatin vivodisruption of the uterine NK cell-DC balance interferes with the decidualization process, with subsequent impact on placental and fetal development leading to fetal growth restriction. Glycans are essential determinants of reproductive health and the glycocode expressed in a particular compartment (e.g., placenta) is highly dependent on the cell type and its developmental and pathological state. Here, we aimed to investigate the maternal and placental glycovariation during the pre- and post-placentation period associated with disruption of the NK cell-DC dynamics during early pregnancy. We observed that depletion of NK cells was associated with significant increases of O- and N-linked glycosylation and sialylation in the decidual vascular zone during the pre-placental period, followed by downregulation of core 1 and poly-LacNAc extended O-glycans and increased expression of branched N-glycans affecting mainly the placental giant cells and spongiotrophoblasts of the junctional zone. On the other hand, expansion of DC induced a milder increase of Tn antigen (truncated form of mucin-type O-glycans) and branched N-glycan expression in the vascular zone, with only modest changes in the glycosylation pattern during the post-placentation period. In both groups, this spatiotemporal variation in the glycosylation pattern of the implantation site was accompanied by corresponding changes in galectin-1 expression. Our results show that pre- and post- placentation implantation sites have a differential glycopattern upon disruption of the NK cell-DC dynamics, suggesting that immune imbalance early in gestation impacts placentation and fetal development by directly influencing the placental glycocode
First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z ~ 7
We present the first results from the ongoing LAGER project (Lyman Alpha
Galaxies in the Epoch of Reionization), which is the largest narrowband survey
for 7 galaxies to date. Using a specially built narrowband filter
NB964 for the superb large-area Dark-Energy Camera (DECam) on the NOAO/CTIO 4m
Blanco telescope, LAGER has collected 34 hours NB964 narrowband imaging data in
the 3 deg COSMOS field. We have identified 23 Lyman Alpha Emitter (LAE)
candidates at = 6.9 in the central 2-deg region, where DECam and public
COSMOS multi-band images exist. The resulting luminosity function can be
described as a Schechter function modified by a significant excess at the
bright end (4 galaxies with 10 erg
s). The number density at 10 erg
s is little changed from z= 6.6, while at fainter it is
substantially reduced. Overall, we see a fourfold reduction in Ly
luminosity density from = 5.7 to 6.9. Combined with a more modest evolution
of the continuum UV luminosity density, this suggests a factor of
suppression of Ly by radiative transfer through the 7
intergalactic medium (IGM). It indicates an IGM neutral fraction
0.4--0.6 (assuming Ly velocity offsets of 100-200 km s).
The changing shape of the Ly luminosity function between and supports the hypothesis of ionized bubbles in a patchy
reionization at 7.Comment: 7 pages, 3 figures (updated), 2 tables (updated), Accepted for
publication in ApJ Letter
A Mountain or a Plateau? Hematological Traits Vary Nonlinearly with Altitude in a Highland Lizard
CONACYT 178723High-altitude organisms exhibit hematological adaptations to augment blood transport of oxygen. One common mechanism is through increased values of blood traits such as erythrocyte count, hematocrit, and hemoglobin concentration. However, a positive relationship between altitude and blood traits is not observed in all high-altitude systems. To understand how organisms adapt to high altitudes, it is important to document physiological patterns related to hypoxia gradients from a greater variety of species. Here, we present an extensive hematological description for three populations of Sceloporus grammicus living at 2,500, 3,400, and 4,300 m. We did not find a linear increase with altitude for any of the blood traits we measured. Instead, we found nonlinear relationships between altitude and the blood traits erythrocyte number, erythrocyte size, hematocrit, and hemoglobin concentration. Erythrocyte number and hematocrit leveled off as altitude increased, whereas hemoglobin concentration and erythrocyte size were highest at intermediate altitude. Additionally, lizards from our three study populations are similar in blood pH, serum electrolytes, glucose, and lactate. Given that the highest-altitude population did not show the highest levels of the variables we measured, we suggest these lizards may be using different adaptations to cope with hypoxia than lizards at low or intermediate altitudes. We discuss future directions that research could take to investigate such potential adaptations
First Spectroscopic Confirmations of z ~ 7.0 Lya Emitting Galaxies in the LAGER Survey
Narrowband imaging is a highly successful approach for finding large numbers
of high redshift Lya emitting galaxies (LAEs) up to z~6.6. However, at z>~7
there are as yet only 3 narrowband selected LAEs with spectroscopic
confirmations (two at z~6.9-7.0, one at z~7.3), which hinders extensive studies
on cosmic reionization and galaxy evolution at this key epoch. We have selected
23 candidate z~6.9 LAEs in COSMOS field with the large area narrowband survey
LAGER (Lyman-Alpha Galaxies at the End of Reionization). In this work we
present spectroscopic followup observations of 12 candidates using IMACS on
Magellan. For 9 of these, the observations are sufficiently deep to detect the
expected lines. Lya emission lines are identified in six sources (yielding a
success rate of 2/3), including 3 luminous LAEs with Lya luminosities of L(Lya)
~ 10^{43.5} erg/s, the highest among known spectroscopically confirmed galaxies
at >~7.0. This triples the sample size of spectroscopically confirmed
narrowband selected LAEs at z>~7, and confirms the bright end bump in the Lya
luminosity function we previously derived based on the photometric sample,
supporting a patchy reionization scenario. Two luminous LAEs appear physically
linked with projected distance of 1.1 pMpc and velocity difference of ~ 170
km/s. They likely sit in a common ionized bubble produced by themselves or with
close neighbors, which reduces the IGM attenuation of Lya. A tentative narrow
NV1240 line is seen in one source, hinting at activity of a central
massive black hole with metal rich line emitting gas.Comment: 6 pages, 3 figures, 2 tables, accepted by ApJ
NK cell-derived IL-10 is critical for DC-NK cell dialogue at the maternal- fetal interface
DC-NK cell interactions are thought to influence the development of maternal
tolerance and de novo angiogenesis during early gestation. However, it is
unclear which mechanism ensures the cooperative dialogue between DC and NK
cells at the feto-maternal interface. In this article, we show that uterine NK
cells are the key source of IL-10 that is required to regulate DC phenotype
and pregnancy success. Upon in vivo expansion of DC during early gestation, NK
cells expressed increased levels of IL-10. Exogenous administration of IL-10
was sufficient to overcome early pregnancy failure in dams treated to achieve
simultaneous DC expansion and NK cell depletion. Remarkably, DC expansion in
IL-10−/− dams provoked pregnancy loss, which could be abrogated by the
adoptive transfer of IL-10+/+ NK cells and not by IL-10−/− NK cells.
Furthermore, the IL-10 expressing NK cells markedly enhanced angiogenic
responses and placental development in DC expanded IL-10−/− dams. Thus, the
capacity of NK cells to secrete IL-10 plays a unique role facilitating the DC-
NK cell dialogue during the establishment of a healthy gestation
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