3,285 research outputs found
Reading Joshua as Christian scripture
No full textThe perception of historical and ethical difficulties associated with Joshua in the twentieth century have led to difficulties in appropriating it as Christian Scripture. I argue that from the perspective of cultural memory Joshua nonetheless has an important role as Scripture, but, moreover, that in engagement with patristic interpretation such difficulties call for Joshua to be read in a different way from that in which it has been since at least the time of Calvin onwards. I develop a way of reading based on recent anthropological approaches to myth, such as those of Victor Turner and Seth Kunin in particular. I combine this treatment of myth with Paul Ricoeur's approach to narrative hermeneutics and the hermeneutics of testimony to produce a reading of Joshua in dialogue with its reception and use in order to argue for a constructive contemporary means of reading Joshua as Christian Scriptur
Thermal spikes from the urban heat island increase mortality and alter physiology of lizard embryos
No full textEffects of global change (i.e. urbanization, climate change) on adult organisms are readily used to predict the persistence of populations. However, effects on embryo survival and patterns of development are less studied, even though embryos are particularly sensitive to abiotic conditions that are altered by global change (e.g. temperature). In reptiles, relatively warm incubation temperatures increase developmental rate and often enhance fitness-relevant phenotypes, but extremely high temperatures cause death. Due to the urban heat island effect, human-altered habitats (i.e. cities) potentially create unusually warm nest conditions that differ from adjacent natural areas in both mean and extreme temperatures. Such vanation may exert selection pressures on embryos. To address this, we measured soil temperatures in places where the Puerto Rican crested anole lizard (Anolis cristatellus) nests in both city and forest habitats. We bred anoles in the laboratory and subjected their eggs to five incubation treatments that mimicked temperature regimes from the field, three of which included brief exposure to extremely high temperatures (i.e. thermal spikes) measured in the city. We monitored growth and survival of hatchlings in the laboratory for 3 months and found that warmer, city temperatures increase developmental rate, but brief, thermal spikes reduce survival. Hatchling growth and survival were unaffected by incubation treatment. The urban landscape can potentially create selection pressures that influence organisms at early (e.g. embryo) and late life stages. Thus, research aimed at quantifying the impacts of urbanization on wildlife populations must include multiple life stages to gain a comprehensive understanding of this important aspect of global change.PublishedYe
Data for: Thermal tolerance in the urban heat island: Thermal sensitivity varies ontogenetically and differs between embryos of two sympatric ectotherms
No full textMost studies of thermal tolerance use adults, but early-life stages (e.g. embryos) are often more sensitive to thermal agitation. Studies that examine effects on embryos rarely assess the potential for thermal tolerance to change with ontogeny or how effects differ among sympatric species, and often utilize unrealistic temperature treatments. We used thermal fluctuations from nests within the urban-heat island to determine how thermal tolerance of embryos changes across development and differs among two sympatric lizard species (Anolis sagrei and A. cristatellus). We applied fluctuations that varied in frequency and magnitude at different times during development and measured effects on embryo physiology, egg survival, and hatchling morphology, growth, and survival. Thermal tolerance differed between the species by ~ 2 °C: embryos of A. sagrei, a lizard that prefers warmer, open-canopy microhabitats, were more robust to thermal stress than embryos of A. cristatellus, which prefers cooler, closed-canopy microhabitats. Moreover, thermal tolerance changed through development; however, the nature of this change differed between the species. For A. cristatellus, thermal tolerance was greatest mid-development. For A. sagrei the relationship was not statistically clear. The greatest effects of thermal stress were on embryo and hatchling survival and embryo physiology. Hatchling morphology and growth were less affected. Inter-specific responses and the timing of stochastic thermal events with respect to development have important effects on egg mortality. Thus, research that integrates ecologically-meaningful thermal treatments, considers multiple life-history stages, and examines interspecific responses will be critical to make robust predictions of the impacts of global change on wildlife.Ye
Joshua David Sierra, piano (Colombia)
No full textJoshua David Sierra nació en Bogotá e inició sus estudios musicales y de piano con su padre, Jimmy David Sierra. A los 16 años ingresó al nivel básico del Conservatorio de Música de la Universidad Nacional de Colombia, donde su formación pianística estuvo a cargo de Mariana Posada. Ha participado también en clases magistrales con Piotr Oczkowski y Jason Ponce.
En 2015, Joshua ocupo el primer lugar como representante del nivel básico para participar en el curso de verano de Hotchkiss School. En 2016 viajo a Lakeville (Connecticut, Estados Unidos) para asistir a dicho curso en calidad de becario, donde tomó clases con Luiz de Moura Castro, Mina Perry, Fabio Witkowski y Priya Mayadas, y en donde también actuó en un recital compartido en el auditorio Katherine M. Elfers Hall. Ese mismo año ganó la convocatoria de solistas de la Orquesta Sinfónica del Conservatorio de Música la Universidad Nacional de Colombia, agrupación con la que presentó el Concierto para piano y orquesta No. 1 de Ludwig van Beethoven.
Joshua David Sierra ha actuado en recitales compartidos y como solista en los auditorios Olav Roots y Guillermo Uribe Holguín de la Universidad Nacional de Colombia y en el auditorio Teresa Cuervo Borda del Museo Nacional. Bajo la dirección de su maestra, Mariana Posada, Joshua presentó su recital de grado en julio de 2021, culminado así sus estudios de pregrado en la Universidad Nacional de Colombia
Life history strategies are decoupled from ecomorphological convergence in two Anolis lizards
No full textConvergence is considered powerful evidence for adaptation to similar natural selection pressures. However, for many ecologically and morphologically convergent species, it remains unclear if convergence extends to reproductive strategies, which are particularly important because of their tight connection to fitness. Here, by measuring key life-history traits (e.g., reproductive status, egg size, oviposition frequency, reproductive effort) across a full annual cycle comprising both reproductive and non-reproductive seasons, we discover divergence in reproductive strategies in two Anolis lizards that are otherwise strikingly convergent in ecology, morphology, and behavior. The Cuban brown anole (A. sagrei) rapidly produces many small eggs during a concentrated summer reproductive season, while the Puerto Rican crested anole (A. cristatellus) produces comparatively fewer, larger eggs over a longer period. Thus, despite evolving highly convergent ecomorphological phenotypes and both being constrained to a single-egg clutch, these species exhibit marked divergence in life-history trade-off strategies along the fast-slow continuum. Our results indicate that ecomorphological convergence evolved uncoupled from life-history pathways in these species.AccpetedYe
Embryo development and global change: how do reptile embryos respond to ecologically relevant thermal stress?
No full textTwo components of global change, climate change and urbanization, contribute to increased ambient temperatures that cause heat stress or mortality in animals. Many animals can respond to harmful temperatures behaviorally; however, embryos of ectotherms which develop inside eggs in the ground and receive little or no parental care cannot respond this way. This early life stage is more vulnerable to harmful temperatures, yet, the effects of ecologically relevant thermal stress on these embryos has received little attention. We measured ground temperatures in an urban landscape where lizards (Anolis sagrei and Anolis cristatellus) nest and exposed eggs to extreme nest temperatures in the lab. We determined the critical thermal maximum for embryos of each species and assessed how thermal tolerance might change through development. Our results show that the thermal tolerance of reptile embryos can differ widely among closely related species, and thermal tolerance can change through development.N
Embryo development and global change: how do reptile embryos respond to ecologically relevant thermal stress?
No full textTwo components of global change, climate change and urbanization, both contribute to increased ambient temperatures that may induce heat stress or mortality in animals. Each phenomenon independently results in both increased mean temperatures and increased maximum day-time temperatures; however, there is also the potential for these components to act synergistically: extreme temperatures due to the urban heat island effect are likely to be exacerbated as the earth’s surface warms due to climate change. Many animals can respond to harmful temperatures behaviorally, by altering their periods of activity or shifting their habitat use. Such behavioral compensation, however, is unavailable to embryos of ectotherms which typically develop inside eggs in the ground and receive little or no parental care. Thus, this early life stage is expected to be more vulnerable to harmful temperatures caused by aspects of global change, and yet, the effects of ecologically relevant thermal stress on these embryos has received little attention. We sought to understand the consequences of such extreme temperatures on embryological development by utilizing two species of lizard (Anolis sagrei and Anolis cristatellus) that commonly inhabit urban areas. We measured ground temperatures in an urban landscape where lizards nest and modeled daily thermal fluctuations that included brief periods of extremely high temperatures. We then subjected eggs of both species to various magnitudes and frequencies of these thermal fluctuations at multiple stages of embryo development. We report results of embryo survival and highlight the potential for extreme incubation temperatures to differentially impact species.N
Constantly fluctuating in an inconsistent way: comparing the effects of sinusoidal and naturally fluctuating incubation temperatures on embryo development
No full textTemperature is a commonly studied environmental factor influencing embryo development in oviparous ectotherms. Though most studies use constant temperature incubation conditions, researchers are aware of the effects of fluctuating temperatures on development. Daily-repeating sinusoidal fluctuations are now commonly used in studies of developmental plasticity; however, thermal fluctuations in natural nests are highly variable from day to day. Thus, using repeated, uniform fluctuations (e.g. sine waves) may still provide an incomplete picture of how embryos develop in the wild and generate inaccurate predictions of how species will respond to future thermal conditions (e.g. climate change). We used eggs from the brown anole lizard (Anolis sagrei) to test the effects of realistic nest temperature fluctuations vs constant temperatures and sinusoidal fluctuations in the lab. We used temperature data from nests to create 4 incubation treatments: a constant mean temperature, a daily-repeating sine fluctuation, a daily-repeating asymmetrical fluctuation (i.e. mean, hourly nest temperatures), and a treatment that allowed each day’s thermal fluctuation to differ from all other days as in real nests. These 4 treatments were created for both early-season (March-April, relatively cool) and late-season (June-July, relatively warm) nest temperatures (2 by 4 factorial design; season x incubation treatment). We report results for developmental rates, physiology (VO2 and heart rate), embryo survival, as well as morphology, performance, growth, and survival of hatchlings. By comparing the effects of several commonly used experimental thermal regimes with those of natural fluctuations, our study assesses the importance of using ecologically relevant incubation conditions when studying developmental plasticity in the laboratory.N
Thermal Spikes Caused by the Urban Heat Island Effect Result in Differential Egg Survival of a Non-native Lizard (Anolis cristatellus)
No full textEmbryonic development in ectotherms is very sensitive to abiotic nest conditions. In reptiles, high incubation temperatures often result in relatively short incubation periods and large hatching size, but extremely high temperatures can result in cardiac arrest and death. Human altered habitats, which potentially create novel thermal conditions in the soil due to the urban heat island effect, may therefore create new selection pressures for developing embryos. The urban heat island effect can increase temperatures in cities as much as 12° C, and our preliminary data suggests that soil temperatures differ markedly between urban and natural areas in locations where reptiles deposit eggs. We measured the temperatures of potential nest sites of the Puerto Rican Crested Anole (Anolis cristatellus) in both urban and natural areas of Miami-Dade county where this lizard and several other anole species are naturalized. We bred crested anoles in the lab and subjected their eggs to 5 incubation treatments that mimic potential temperature regimes from our field data, three of which included a thermal spike 1/4 of the way through embryonic development. Preliminary results suggest that thermal spikes increase metabolism and reduce egg survival and that each are a function of the magnitude of the spike. These results suggest that urban environments create novel selection pressures that potentially result in embryonic adaptation to novel temperature regimes or in novel nest-site selection strategies by females.N
Embryological development and global change: how do reptile embryos respond to thermal stress in urban environments?
No full textTwo components of global change, climate change and urbanization, both contribute to increased ambient temperatures that may induce heat stress or mortality in animals. Each phenomenon independently results in both increased mean temperatures and increased maximum day-time temperatures; however, there is also the potential for these components to act synergistically: extreme temperatures due to the urban heat island effect are likely to be exacerbated as the earth’s surface warms due to climate change. Many animals can respond to harmful temperatures behaviorally, by altering their periods of activity or shifting their habitat use. Such behavioral compensation, however, is unavailable to embryos of ectotherms which typically develop inside eggs in the ground and receive little or no parental care. Thus, this early life stage is expected to be more vulnerable to harmful temperatures caused by aspects of global change, and yet, the effects of ecologically relevant thermal stress on these embryos has received little attention. We sought to understand the consequences of such extreme temperatures on embryological development by utilizing two species of lizard (Anolis sagrei and Anolis cristatellus) that commonly inhabit urban areas. We measured ground temperatures in an urban landscape where lizards nest and modeled daily thermal fluctuations that included brief periods of extremely high temperatures. We then subjected eggs of both species to various magnitudes and frequencies of these thermal fluctuations at multiple stages of embryological development. We report the effects on survival, physiology, morphology, and performance of these ecologically relevant thermal regimes and highlight the potential for extreme incubation temperatures to differentially impact species.N
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