3,691 research outputs found
The Emergence of the Bird in Andean Paracas Art. c. 900 BCE - 200 CE
In the first millennium BCE, an enigmatic cultural group now known as Paracas inhabited the remote desert coast of southern Peru. Following its disappearance, Paracas culture did not emerge in the historical record until 1927, when three burial centers were scientifically excavated on the arid Paracas peninsula that gave the culture its name. The burials contained over 400 mummy bundles that preserved the only physical remnants of this culture and its unique art forms. When unwrapped, mummy bundles of elite males revealed multiple layers of finely woven and elaborately embroidered textiles and painted ceramics, along with gold objects, feathers, and other finely crafted artifacts. Such items indicate that the individuals were part of a stratified village society whose members participated in complex ceremonial activities. The art works feature figural imagery based, to a great extent, on the numerous species of sea, air, and land fauna of the south coastal area. In fact, avian imagery and costumes, generally understood to represent humans impersonating supernaturals, dominate in Paracas iconography. The intensity of this interest in birds, demonstrated by their prominence in the art forms, indicates that they held special meaning and value in Paracas society.
In addition to art historical methodologies, this project investigates the emergence of avian imagery and costume in Paracas art by employing the approach of evolutionary aesthetics. It interprets these avian subjects and feathered accessories as reflections of evolved aesthetic inclinations, activated and amplified by the rich bird life in the Paracas region, local ideology, and social needs of the elite members of this hierarchical society. Inspired by the ecology of the Paracas coastal realm, the emergence of the bird in Paracas art initiated a break from an earlier supernatural triad of serpent, bird, and jaguar forged in the first millennium in the Andean highlands. This avian intervention thus reveals a previously unrecognized artistic and ideological agency among Paracas people that demonstrates that they were much more autonomous and inventive than previously acknowledged in scholarship. My study of the small-scale, coastal Paracas society, frequently overlooked in favor of larger highland cultures such as the earlier ChavĂn and later Inca, also enriches our understanding of the artistic contributions of the many diverse cultures of the South American Andes and the Pre-Columbian Americas as a whole
Ecological correlates of group integrity among dispersing cliff swallows
Breeding colonies of birds represent groups of individuals that associate during one breeding season, at least partially dissociate for the non-breeding season, and may re-associate the next year through collective settlement at another breeding site. Little is known about the extent to which colonial birds maintain group integrity when occupying different sites in different years or the benefits of long-term associations among colonial individuals. For cliff swallows (Petrochelidon pyrrhonota) in western Nebraska, USA, we examined ecological correlates and potential benefits associated with group integrity. Using a dataset of over 25,000 individuals, we found that associations between dispersing cliff swallows were greater than would be predicted by purely random settlement among colony sites. The extent of group integrity varied widely among sites, with birds seeming to settle together more often at sites with fewer ectoparasites and at colonies similar in size and closer in physical proximity to the one they had previously occupied. Some associations of birds lasted three years in which they used a different site each year. Successful colonies had higher levels of group integrity among their settlers than did colonies that failed completely. Cliff swallows that were known to have settled with at least one conspecific from the previous year’s site had a higher survival the next year than those not known to have settled with past residents. The results are consistent with cliff swallows choosing colonies based in part on parasite load and with sorting among colonies based on the birds’ preferences for colonies of certain sizes
M1/M2 Macrophage Polarity in Normal and Complicated Pregnancy
Tissue macrophages play an important role in all stages of pregnancy, including uterine stromal remodeling (decidualization) before embryo implantation, parturition, and postpartum uterine involution. The activation state and function of utero-placental macrophages are largely dependent on the local tissue microenvironment. Thus, macrophages are involved in a variety of activities such as regulation of immune cell activities, placental cell invasion, angiogenesis, and tissue remodeling. Disruption of the uterine microenvironment, particularly during the early stages of pregnancy (decidualization, implantation, and placentation) can have profound effects on macrophage activity and subsequently impact pregnancy outcome. In this review, we will provide an overview of the temporal and spatial regulation of utero-placental macrophage activation during normal pregnancy in humans and rodents with a focus on more recent findings. We will also discuss the role of M1/M2 dysregulation within the intrauterine environment during adverse pregnancy outcomes
Reproductive ecology of interior least tern and piping plover in relation to Platte River hydrology and sandbar dynamics
Historical and contemporary use of large, economically important rivers by threatened and/or endangered species in the United States is a subject of great interest to a wide range of stakeholders. In a recent study of the Platte River in Nebraska, Farnsworth et al. (2017) (hereinafter referred to as “the authors” or “Farnsworth et al.”) used distributions of nest initiation dates taken mostly from human-created, off-channel habitats and a model of emergent sandbar habitat to evaluate the hypothesis that least terns (Sternula antillarum) and piping plovers (Charadrius melodus) are physiologically adapted to initiate nests concurrent with the cessation of spring river flow rises. The authors conclude that (1) these species are not now, nor were they in the past, physiologically adapted to the hydrology of the Platte River, (2) habitats in the Platte River did not, and cannot support reproductive levels sufficient to maintain species subpopulations, (3) the gap in local elevation between peak river stage and typical sandbar height, in combination with the timing of the average spring flood, creates a physical environment which limits opportunities for successful nesting and precludes persistence by either species, and (4) the presence of off-channel habitats, including human-created sand and gravel mines, natural lakes, and a playa wetland, allowed the species to expand into the Platte River basin
A Comparative Study of Collegiate Aviation Students and Business Students Related to Myers-Briggs Type Indicator Preferences
There has been limited research to date that addresses the difference, if any, between students who choose the various fields of aviation as a major, and those who choose other majors, particularly business. This study utilizes the Myers-Briggs Type Indicator (MBTI) to compare preferences of aviation majors to business majors because of its unique characteristics and its noted lack of use in the aviation arena. The findings of the study revealed that there are no significant differences between business and aviation students in the Myers-Briggs Type Indicators except in the way they orient themselves in the environment (Judging and Perceiving). These findings are a reminder to teachers of aviation students that classroom structure should balance discussion, practice skills, fun and other activities with learning objectives to accommodate the dominant styles of aviation learners. On the other hand, the predominant Judging style of business students would demand that classroom discussion be somewhat limited in order to meet specific learning goals. Maintaining a balance of teaching style is important both for the teacher and the student in reducing the discomfort of the teacher operating outside a preferred style and eliminating the mental stress of the student attempting to learn new material while using an auxiliary type
Predation risk: a potential mechanism for effects of a wind energy facility on Greater Prairie-Chicken survival
Recent expansion of the wind energy industry has raised concerns about the potential effects of wind energy facilities on prairie grouse. For example, efforts have been made to evaluate indirect effects on prairie grouse survival, but it is also critical to investigate the underlying mechanisms to direct conservation strategies. The objective of this study was to investigate the indirect effects of a wind energy facility on the survival of female Greater Prairie-Chickens (Tympanuchus cupido pinnatus) and on the occupancy of avian and mammalian predators. Between March and July of 2013 and 2014, we investigated spatial variation in predation risk by sampling occupancy of mammalian and avian predators within 10 km of a wind energy facility constructed in 2005 in Brown County, Nebraska, USA. During the same period, we assessed spatial variation in daily survival of radio-marked females within the same area.We found little evidence that probability of site occupancy (Ψ) of avian predators was lower near the wind energy facility (within 2 km: Ψ = 0.70, 95% CI = 0.22–0.95; beyond 2 km: Ψ = 0.93, 95% CI = 0.02–1.00), suggesting that avian predators did not display local-scale avoidance behavior around wind turbines. Mammalian predators were documented at all of our sample locations, but the capture index for all mammals was lower at sample sites near the wind turbines (P = 0.004). Occupancy of coyotes (Canis latrans), the likely main mammalian predator of adult prairie-chickens in the area, did not vary significantly throughout our study site (within 0.5 km of wind energy facility: Ψ = 0.65, 95% CI = 0.07–0.98; beyond 0.5 km: Ψ = 0.96, 95% CI = 0.04–1.00), although trends were in the direction expected if coyotes were avoiding the wind energy facility. Distance to wind turbine had no effect on daily survival (SD) of female prairie-chickens (SD = 0.9948, SE = 0.0015). The potential for predators to avoid wind energy facilities, and thus affect predation risk, underscores the complexity of planning to address potential impacts of wind energy as variation in predation risk may have consequences for the population viability of a wide range of species at risk from wind energy development
Clinical Associations with Immature Breathing in Preterm Infants. Part 2: Periodic Breathing
Background: Periodic breathing (PB) is a normal immature breathing pattern in neonates that, if extreme, may be associated with pathologic conditions.
Methods: We used our automated PB detection system to analyze all bedside monitor chest impedance data on all infants \u3c 35 wk\u27 gestation in the University of Virginia Neonatal Intensive Care Unit from 2009-2014 (n = 1,211). Percent time spent in PB was calculated hourly ( \u3e 50 infant-years\u27 data). Extreme PB was identified as a 12-h period with PB \u3e 6 SDs above the mean for gestational age (GA) and postmenstrual age and \u3e 10% time in PB.
Results: PB increased with GA, with the highest amount in infants 30-33 wk\u27 GA at about 2 wk\u27 chronologic age. Extreme PB was identified in 76 infants and in 45% was temporally associated with clinical events including infection or necrotizing enterocolitis (NEC), immunizations, or caffeine discontinuation. In 8 out of 28 cases of septicemia and 10 out of 21 cases of NEC, there was a \u3e 2-fold increase in %PB over baseline on the day prior to diagnosis.
Conclusion: Infants \u3c 35 wk GA spend, on average, \u3c 6% of the time in PB. An acute increase in PB may reflect illness or physiological stressors or may occur without any apparent clinical event
Clinical Associations of Immature Breathing in Preterm Infants. Part 1: Central Apnea
Background: Apnea of prematurity (AOP) is nearly universal among very preterm infants, but neither the apnea burden nor its clinical associations have been systematically studied in a large consecutive cohort.
Methods: We analyzed continuous bedside monitor chest impedance and electrocardiographic waveforms and oxygen saturation data collected on all neonatal intensive care unit (NICU) patients \u3c35 wk gestation from 2009 to 2014 (n = 1,211; \u3e50 infant-years of data). Apneas, with bradycardia and desaturation (ABDs), defined as central apnea ≥10 s associated with both bradycardia \u3c100 bpm and oxygen desaturation \u3c80%, were identified using a validated automated algorithm.
Results: Number and duration of apnea events decreased with increasing gestational age (GA) and postmenstrual age (PMA). ABDs were more frequent in infants \u3c31 wk GA at birth but were not more frequent in those with severe retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD), or severe intraventricular hemorrhage (IVH) after accounting for GA. In the day before diagnosis of late-onset septicemia and necrotizing enterocolitis, ABD events were increased in some infants. Many infants continued to experience short ABD events in the week prior to discharge home.
Conclusion: Frequency of apnea events is a function of GA and PMA in infants born preterm, and increased apnea is associated with acute but not with chronic pathologic conditions
The earth observing one (EO-1) Hyperion and Advanced land imager sensors for use in tundra classification studies within the Upper Kuparuk river basin, Alaska
The heterogeneity of Arctic vegetation can make land cover classification very difficult when using medium to small resolution imagery (Schneider et al., 2009; Muller et al., 1999). Using high radiometric and spatial resolution imagery, such as the SPOT 5 and IKONOS satellites, have helped arctic land cover classification accuracies rise into the 80 and 90 percentiles (Allard, 2003; Stine et al., 2010; Muller et al., 1999). However, those increases usually come at a high price. High resolution imagery is very expensive and can often add tens of thousands of dollars onto the cost of the research. The EO-1 satellite launched in 2002 carries two sensors that have high spectral and/or high spatial resolutions and can be an acceptable compromise between the resolution versus cost issues. The Hyperion is a hyperspectral sensor with the capability of collecting 242 spectral bands of information. The Advanced Land Imager (ALI) is an advanced multispectral sensor whose spatial resolution can be sharpened to 10 meters. This dissertation compares the accuracies of arctic land cover classifications produced by the Hyperion and ALI sensors to the classification accuracies produced by the Systeme Pour l' Observation de le Terre (SPOT), the Landsat Thematic Mapper (TM) and the Landsat Enhanced Thematic Mapper Plus (ETM+) sensors. Hyperion and ALI images from August 2004 were collected over the Upper Kuparuk River Basin, Alaska. Image processing included the stepwise discriminant analysis of pixels that were positively classified from coinciding ground control points, geometric and radiometric correction, and principle component analysis. Finally, stratified random sampling was used to perform accuracy assessments on satellite derived land cover classifications. Accuracy was estimated from an error matrix (confusion matrix) that provided the overall, producer's and user's accuracies. This research found that while the Hyperion sensor produced classification accuracies that were equivalent to the TM and ETM+ sensor (approximately 78%), the Hyperion could not obtain the accuracy of the SPOT 5 HRV sensor. However, the land cover classifications derived from the ALI sensor exceeded most classification accuracies derived from the TM and ETM+ sensors and were even comparable to most SPOT 5 HRV classifications (87%). With the deactivation of the Landsat series satellites, the monitoring of remote locations such as in the Arctic on an uninterrupted basis throughout the world is in jeopardy. The utilization of the Hyperion and ALI sensors are a way to keep that endeavor operational. By keeping the ALI sensor active at all times, uninterrupted observation of the entire Earth can be accomplished. Keeping the Hyperion sensor as a "tasked" sensor can provide scientists with additional imagery and options for their studies without overburdening storage issues
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