1,683 research outputs found

    Predator-based Selection and the Impact of Edge Sympatry on Components of Coralsnake Mimicry

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    Studying warning coloration and mimicry is an effective way to understand predator-driven selection and phenotypic diversity. The presence (sympatry) or absence (allopatry) of a toxic model plays a role in shaping mimetic phenotypes. However, the impact of edge sympatry and allopatry on predation of mimetic phenotypes is not well understood. We studied coralsnake mimicry to test how edge sympatry and allopatry affect predation on mimetic phenotypes. Specifically, we tested 1) if overall attack rates varied with edge sympatry of coralsnakes 2) which color patterns conferred a fitness advantage 3) which specific mimetic signal components are important in driving predatory attacks and 4) whether selection patterns varied temporally. We deployed clay replicas that utilized a cryptic pattern, two different signal components (red and white), and a tricolor pattern that included both signal components. We found that overall attacks did differ between edge sympatry and allopatry, with higher attack rates in allopatry. All mimetic phenotypes in 2019 had higher attack rates than cryptic phenotypes in edge sympatry, with a similar but nonspecific pattern in allopatry. Replicas with red and bands received more predatory attacks in edge sympatry than those without, once again with a similar pattern in allopatry. There was also a difference in attack rates and patterns between years, indicating temporally variable selection such as frequency-dependent selection. These results suggest that mimetic phenotypes may not have a fitness advantage in areas of edge sympatry or allopatry. This suggests the role of sympatry and allopatry may be more complex than previously thought, particularly in how sympatry may interact with extraneous factors such as behavior and frequency of phenotypes

    Building a community of practice: shifting an M.Ed. program to a PDS school-based cohort model

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    Purpose The purpose of this study was to examine how participants experienced and perceived an M.Ed. program that had a school-based design. In particular, the authors sought to understand: (1) how participants experienced being in a school-based cohort and (2) whether and how participants experienced the three designated tenets of the M.Ed. program: teacher inquiry, social justice and student engagement and motivation. Design/methodology/approach This qualitative study used semi-structured focus group interviews (n = 7) to examine teachers’ perceptions, using a constant comparative method (Corbin & Strauss, 2008) of open coding to analyze the data and determine emergent themes. Findings The findings indicate the design of this school-based M.Ed. program provided both social and academic benefits including strengthening teachers’ working relationships and their understanding of students outside their own classroom and a transfer from individual learning to organizational benefit. Teachers positively perceived the three tenets that guided the first year of the program, especially the ability to study social justice and student motivation in depth. Practical implications This study has implications for teacher education and retention as well as how boundary spanning roles in PDS schools can impact graduate students’ experiences in schools. Given the current teacher shortage concerns, it is important to understand how M.Ed. programs can be designed with teacher needs at the forefront so learning is relevant and rewarding, both to the individual and the school. Originality/value While there are many studies that examine the use of cohorts in education, particularly in doctoral programs, few, if any, studies examine a school-based cohort M.Ed. program for practicing teachers. This study also puts a unique spotlight on how boundary-spanning roles can benefit not only teacher candidates but also practicing teachers in their M.Ed. program

    Effect of Conventional or High Protein Dry Distillers Grains Plus Solubles in Either Dry- Rolled or Steam- Flaked Corn Based Diets on Amount and Site of Nutrient Digestion

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    A 2 Ă— 3 factorial metabolism study using 6 ruminally and duodenally cannulated heifers evaluated the site and amount of nutrient digestion when feeding high protein dry distillers grains plus solubles (DDGS) or conventionally produced DDGS at 30% inclusion compared to feeding no distillers in either dry- rolled or steam- flaked corn diets. Apparent total tract starch digestibility was unaffected by distillers treatment in SFCbased diets, but decreased from 95.1% to 92.0% when DDGS was added to DRC diets, and further decreased to 88.7% for HiPro diets. Dry matter and OM digestibilities were lower types of when either DDGS diets were fed, but no differences were observed between conventional or high protein DDGS. Feeding high protein DDGS did not change digestion compared to conventional DDGS, despite higher CP content. Digestion is greater when cattle are fed steam- flaked corn compared to dry- rolled corn

    Two new species of Pteropus from Samoa, probably extinct.

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    37 p. : ill., maps ; 26 cm. "June 25, 2009." Includes bibliographical references (p. 30-37).Two new species of flying foxes (genus Pteropus) from the Samoan archipelago are described on the basis of modern museum specimens collected in the mid-19th century. A medium-sized species (P. allenorum, n. sp.) is introduced from the island of Upolu (Independent Samoa), based on a specimen collected in 1856 and deposited in the Academy of Natural Sciences of Philadelphia. It has not been collected again, and we regard it as almost certainly extinct. This species is smaller bodied and has much smaller teeth than both extant congeners recorded in the contemporary fauna of Samoa (Pteropus samoensis and P. tonganus). The closest relative of this new species may be Pteropus fundatus of northern Vanuatu. The disjunct historical distribution of these two small-toothed flying foxes (in Vanuatu and Samoa) suggests that similar species may have been more extensively distributed in the remote Pacific in the recent past. Another species, a very large flying fox with large teeth (P. coxi, n. sp.), is described from two skulls collected in Samoa in 1839-1841 during the U.S. Exploring Expedition; it too has not been collected since. This robust species resembles Pteropus samoensis and Pteropus anetianus of Vanuatu in craniodental conformation but is larger than other Polynesian Pteropus, and in some features it is ecomorphologically convergent on the Pacific monkey-faced bats (the pteropodid genera Pteralopex and Mirimiri). On the basis of eyewitness reports from the early 1980s, it is possible that this species survived until recent decades, or is still extant. These two new Samoan species join Pteropus tokudae of Guam, P. pilosus of Palau, P. subniger of the Mascarenes, and P. brunneus of coastal north-eastern Australia as flying foxes with limited insular distributions that survived at least until the 19th century but are now most likely extinct.American Museum of Natural History

    Cross-sectional associations between domain-specific sitting time and other lifestyle health behaviours: the Stormont study

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    BackgroundThere is a dearth of literature on how different domains of sitting time relate to other health behaviours. Therefore, this study aimed to explore these associations in a sample of office workers.Methods7170 Northern Irish Civil Servants completed an online survey which included information on workday and non-workday sitting time in five domains (travel, work, TV, computer-use, leisure-time), physical activity, fruit and vegetable intake, alcohol consumption and cigarette smoking. An unhealthy behaviour score was calculated by summing the number of health behaviours which did not meet the current guidelines. Multinomial regressions examined associations between unhealthy behaviour score and each domain of sitting time.Results≥7 hours sitting at work and ≥2 hours TV viewing on a workday both more than doubled the odds of partaking in ≥3 unhealthy behaviours [Odds ratio, OR = 2.03, 95% CI, (1.59–2.61); OR = 2.19 (1.71–2.80)] and ≥3 hours of TV viewing on a non-workday nearly tripled the odds [OR = 2.96 (2.32–3.77)].ConclusionsHigh sitting time at work and TV viewing on a workday and non-workday are associated with increased odds of partaking in multiple unhealthy behaviours. Interventions need to focus on these domains and public health policy should consider sitting time as an important health behaviour

    From structure to crystallisation and pharmaceutical manufacturing: the CSD in CMAC Workflows

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    Two Workflows are presented that are relevant to the design and construction of end-to-end pharmaceutiucal manufacturing processes. The Workflows target the very early stage crystallisation aspect of these processes – production of the primary crystalline solid form – and relate to establishing decision-driven approaches for the screening for multi-component forms, specifically co-crystals, and to the use of additives to control crystal and primary particle form, notably morphology. These Workflows are shown to benefit from the use of the Million-plus structures in the Cambridge Structural Database and the associated structural informatics and analysis tools and are placed into the context of the work of the CMAC Future Manufacturing Hub

    Simulation models predict that school-age children are responsible for most human-to-mosquito Plasmodium falciparum transmission in southern Malawi

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    Abstract Background Malaria persists in some high-transmission areas despite extensive control efforts. Progress toward elimination may require effective targeting of specific human populations that act as key transmission reservoirs. Methods Parameterized using molecular-based Plasmodium falciparum infection data from cross-sectional community studies in southern Malawi, a simulation model was developed to predict the proportions of human-to-mosquito transmission arising from (a) children under 5 years old (U5s), (b) school-age children (SAC, 5–15 years), (c) young adults (16–30 years), and (d) adults > 30 years. The model incorporates mosquito biting heterogeneity and differential infectivity (i.e. probability that a blood-fed mosquito develops oocysts) by age and gametocyte density. Results The model predicted that SAC were responsible for more than 60% of new mosquito infections in both dry and rainy seasons, even though they comprise only 30% of this southern Malawi population. Young adults were the second largest contributors, while U5s and adults over 30 were each responsible for < 10% of transmission. While the specific predicted values are sensitive to the relative infectiousness of SAC, this group remained the most important contributor to mosquito infections under all realistic estimates. Conclusions These results suggest that U5 children play a small role compared to SAC in maintaining P. falciparum transmission in southern Malawi. Models that assume biting homogeneity overestimate the importance of U5s. To reduce transmission, interventions will need to reach more SAC and young adults. This publicly available model can be used by others to estimate age-specific transmission contributions in epidemiologically similar sites with local parameter estimates of P. falciparum prevalence and bed net use.https://deepblue.lib.umich.edu/bitstream/2027.42/143001/1/12936_2018_Article_2295.pd

    A new class of ratiometric small molecule intracellular pH sensors for Raman microscopy

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    Intracellular pH (pHi) homeostasis is intertwined with a myriad of normal cellular behaviors as well as pathological processes. As such, small molecule probes for the measurement of pHi are invaluable tools for chemical biology, facilitating the study of the role of pH in cellular function and disease. The field of small molecule pHi sensors has traditionally been dominated with probes based on fluorescent scaffolds. In this study, a series of low molecular weight (<260) oligoyne compounds have been developed which exhibit pH sensitive alkyne stretching frequencies (νalkyne) in Raman spectroscopy. The modular design of the compounds enabled tuneability of their pKa(H) through simple structural modification, such that continuous pH sensitivity is achieved over the range 2-10. Alkyne stretching bands reside in the 'cell-silent' region of the Raman spectrum (1800-2600 cm-1) and are readily detectable in a cellular environment with subcellular spatial resolution. This enabled the application of a pH sensitive oligoyne compound to the ratiometric sensing of pHi in prostate cancer (PC3) cells in response to drug treatment. We propose that probes based on Alkyne Tag Raman Imaging offer an entirely new platform for the sensing of pHi, complementary to fluorescence microscopy

    Comparative study of the dynamics of laser and acoustically generated bubbles in viscoelastic media

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    Experimental observations of the growth and collapse of acoustically and laser-nucleated single bubbles in water and agarose gels of varying stiffness are presented. The maximum radii of generated bubbles decreased as the stiffness of the media increased for both nucleation modalities, but the maximum radii of laser-nucleated bubbles decreased more rapidly than acoustically nucleated bubbles as the gel stiffness increased. For water and low stiffness gels, the collapse times were well predicted by a Rayleigh cavity, but bubbles collapsed faster than predicted in the higher stiffness gels. The growth and collapse phases occurred symmetrically (in time) about the maximum radius in water but not in gels, where the duration of the growth phase decreased more than the collapse phase as gel stiffness increased. Numerical simulations of the bubble dynamics in viscoelastic media showed varying degrees of success in accurately predicting the observations
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