Flexible responses to stage‐specific offspring threats

When caring for their young, parents must compensate for threats to offspring survival in a manner that maximizes their lifetime reproductive success. In birds, parents respond to offspring threats by altering reproductive strategies throughout the breeding attempt. Because altered reproductive strategies are costly, when threats to offspring are limited, parents should exhibit a limited response. However, it is unclear if response to offspring threat is the result of an integrated set of correlated changes throughout the breeding attempt or if responses are a flexible set of dissociable changes that are stage‐specific. We test these hypotheses in a system where house wrens (Troglodytes aedon) compete for nesting cavities with Carolina chickadees (Poecile carolinensis) by usurping and destroying their nests during the early stage of the breeding attempt (the egg stage). Due to the specificity of the house wren threat, we can test whether parental responses to an offspring threat show flexibility and stage specificity or if parental strategies are an integrated and persistent response. We monitored nests in a natural population to compare life history traits of chickadees nesting in boxes that were in the presence of house wrens to chickadees nesting in boxes that did not overlap with house wrens. Carolina chickadees that nested near house wrens laid significantly smaller clutch sizes (early change in reproductive strategy) but did not alter nestling provisioning or nestling stage length (late change in reproductive strategy), suggesting that chickadees respond in a flexible and stage‐specific manner to the threat of house wrens. By responding only when a threat is highest, parents minimize the cost of antithreat responses. Our study suggests that parents can respond in subtle and nuanced ways to offspring threats in the environment and specifically alter reproductive behaviors at the appropriate stage.Highlands Plateau Audubon Society; Western Carolina UniversityOpen access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Oxygen isotopes in bioarchaeology : Principles and applications, challenges and opportunities

The Max-Planck-Society and the University of Aberdeen are thanked for professional and financial support during production of this manuscript. Ciara Gigleux of CG editing is thanked for help with copy-editing. Thanks are also due to Matthew Collins (Copenhagen/Cambridge) and Michelle Alexander (York) for contributions to the production of Figure 8. We also thank the Editors and two anonymous reviewers whose comments on an earlier version of this manuscript greatly improved this work.Peer reviewedPostprin

Anion exchange resin and slow precipitation preclude the need for pretreatments in silver phosphate preparation for oxygen isotope analysis of bioapatites

The authors would like to thank Wolfram Meier-Augenstein (Robert Gordon University) for advice on TC/EA677 IRMS and to Raquel Maria (Kimmel Center for Archaeological Science, Weizmann Institute of Science) for advice on FTIR-ATR. Thanks to Birke Brumme (MPI EVA) for practical support with sample preparation. Thanks are also due to Sahra Talamo (MPI EVA/University of Bologna) for providing aliquots of the S-EVA-2000 and S-EVA-2001 in-house bone standards and to Klervia Jaouen (MPI EVA/Géosciences Environnment Toulouse) for providing extracted collagen used in the preparation of synthetic bones. This research was funded by the Max-Planck-Society as part of SP’s doctoral research. The authors would also like to thank the Max-Planck-Society, the University of Aberdeen and the Vreije Universiteit Brussels for professional and financial support during the production of this manuscript. CS thanks the Research Foundation - Flanders for his post-doctoral fellowship. We also thank Christophe Lécuyer and an anonymous reviewer for their valuable comments and suggestions.Peer reviewedPostprin

The Effects of Middle Cerebral Artery Occlusion on Central Nervous System Apoptotic Events in Normal and Diabetic Rats

Apoptosis and neural degeneration are characteristics of cerebral ischemia and brain damage. Diabetes is associated with worsening of brain damage following ischemic events. In this study, the authors characterize the influence of focal cerebral ischemia, induced by middle cerebral artery occlusion, on 2 indexes of apoptosis,TUNEL(terminal deoxynucleotidyl transferase–mediated deoxyuridine 5-triphosphate nick end-labeling) staining and caspase- 3 immunohistochemistry. Diabetes was induced in normal rats using streptozotocin and maintained for 5 to 6 weeks. The middle cerebral artery of both normal and diabetic rats was occluded and maintained from 24 or 48 hours. Sham-operated normal and diabetic animals served as controls. Following 24 to 48 hours of occlusion, the animals were sacrificed and the brains were removed, sectioned, and processed for TUNEL staining or caspase-3 immunohistochemistry. Middle cerebral artery occlusion in normal rats was associated with an increase in the number of both TUNEL-positive and caspase-3– positive cells in selected brain regions (hypothalamic preoptic area, piriform cortex, and parietal cortex) when compared to nonoccluded controls. Diabetic rats without occlusion showed significant increases in both TUNEL-positive and caspase-3–positive cells compared to normal controls. Middle cerebral artery occlusion in diabetic rats resulted in increases in TUNEL-positive as well as caspase-3–positive cells in selected regions, above those seen in nonoccluded diabetic rats. Both TUNEL staining and caspase-3 immunohistochemistry revealed that the number of apoptotic cells in diabetic animals tended to be greatest in the preoptic area and parietal cortex. The authors conclude that focal cerebral ischemia is associated with a significant increase in apoptosis in nondiabetic rats, and that diabetes alone or diabetes plus focal ischemia are associated with significant increases in apoptotic cells

Thoughtful Laughter: Fantasy and Satire as Social Commentary in Terry Pratchett's "Discworld"

By examining the use of comedy and satire in the fantasy genre and the purpose of secondary worldbuilding, the author determines how Terry Pratchett's "Discworld" constitutes a safe platform for social critique, and gives special attention to one of Pratchett's most popular characters, Death

The effect of worrying on intolerance of uncertainty and positive and negative beliefs about worry

Background and Objectives: The effect of a worry manipulation on the clinical constructs intolerance of uncertainty (IU), negative beliefs about the consequences of worry (NCOW), positive beliefs about the consequences of worry (PCOW), in addition to the emotions anxiety and sadness, was examined. Methods: A non-clinical sample was split into two groups, a worry group (n = 29), who were asked to generate 20 potential worries about a hypothetical scenario, and a control group (n = 28), who were asked to generate 2 potential worries about the same scenario. Subsequently, participants were asked to complete measures of IU, NCOW, PCOW, sadness and anxiety. Results: The worry group scored significantly higher than the control group on measures of IU, NCOW and PCOW but not on measures of sadness and anxiety. Limitations: Possible limitations of the current study include the use of a student sample and the use of a hypothetical worry scenario. Conclusions: The results suggest that engaging in worry can increase scores on measures of the beliefs and thought patterns often used to causally explain worry. The results are in line with recent research showing bidirectionality between anxiety related symptoms and their associated clinical constructs, and are consistent with an approach which sees anxiety symptoms as part of an evolved integrated threat management system that alerts the individual to threats to goals or challenges, and coordinates cognitive, behavioral, and affective reactions to enable effective responding to these threats and challenges

Indirect effects of a competitor on life history and reproductive traits in a cavity nesting bird

Research on life history evolution in birds has revealed both direct and indirect effects of predation. Increased levels of nest predation favor reproductive behaviors that reduce the threat of predators on offspring or allow parents to bet hedge for future reproductive attempts. In this study, I investigate whether the presence of a competitor, the house wren (Troglodytes aedon), results in similar indirect effects on life history and reproductive behaviors of Carolina chickadees (Poecile carolinensis). House wrens compete for nesting cavities and will kill Carolina chickadee eggs and nestlings. I monitored nest boxes in Western North Carolina where exposure to house wrens varies. I surveyed house wren presence at active Carolina chickadee nests and measured clutch size and mass, incubation, provisioning rates, nestling growth rates, development, and fledging success of chickadees. House wren takeover accounted for 35% of nesting failures, more than any other cause of failure in our study. I found smaller clutch sizes in areas where house wrens were present. However, I did not detect any effects of house wren presence on chickadee egg size, incubation, provisioning, growth, or development. These results suggest that house wren presence affects a narrow range of life history traits early in the nesting period, possibly because this is when house wrens are the biggest threat. Reducing clutch size may be a strategy used by Carolina chickadees to decrease reproductive investment in an environment where early nest failure is probable, allowing adults to reserve energy for survival to the next breeding season

The low-redshift circumgalactic medium in SIMBA

We examine the properties of the low-redshift circumgalactic medium (CGM) around star-forming and quenched galaxies in the Simba cosmological hydrodynamic simulations, focusing on comparing HI and metal line absorption to observations from the COS-Halos and COS-Dwarfs surveys. Halo baryon fractions are always well below the cosmic fraction due to stellar feedback at low masses, and jet-mode AGN feedback at high masses. Baryons and metals in the CGM of quenched galaxies are mostly in hot gas, while the CGM of star-forming galaxies is more multiphase. Hot CGM gas has low metallicity, while warm and cool CGM gas have metallicity close to that of galactic gas. Equivalent widths, covering fractions and total path absorption of HI and selected metal lines (MgII, SiIII, CIV and OVI) around a matched sample of Simba galaxies are broadly consistent with COS-Halos and COS-Dwarfs observations. Absorption is higher around star forming galaxies, and drops with radius. HI absorption around Simba star-forming galaxies is in good agreement with observations, however around quenched galaxies HI absorption is under-predicted. Metal-line absorption is sensitive to choice of photo-ionising background; assuming recent backgrounds, Simba matches OVI but under-predicts low ions, while an older background matches low ions but under-predicts OVI. Simba reproduces the observed dichotomy of OVI absorption around star forming and quenched galaxies. CGM metals primarily come from stellar feedback, while jet-mode AGN feedback reduces absorption particularly for lower ions.Comment: 23 pages, 12 figures, submitted to MNRAS. Comments welcom

Status of implementation of Framework Convention on Tobacco Control (FCTC) in Ghana: a qualitative study

BACKGROUND: The Framework Convention on Tobacco Control (FCTC), a World Health Organization treaty, has now been ratified by over 165 countries. However there are concerns that implementing the Articles of the treaty may prove difficult, particularly in the developing world. In this study we have used qualitative methods to explore the extent to which the FCTC has been implemented in Ghana, a developing country that was 39th to ratify the FCTC, and identify barriers to effective FCTC implementation in low income countries. METHODS: Semi-structured interviews with 20 members of the national steering committee for tobacco control in Ghana, the official multi-disciplinary team with responsibility for tobacco control advocacy and policy formulation, were conducted. The Framework method for analysis and NVivo software were used to identify key issues relating to the awareness of the FCTC and the key challenges and achievements in Ghana to date. RESULTS: Interviewees had good knowledge of the content of the FCTC, and reported that although Ghana had no explicitly written policy on tobacco control, the Ministry of Health had issued several tobacco control directives before and since ratification. A national tobacco control bill has been drafted but has not been implemented. Challenges identified included the absence of a legal framework for implementing the FCTC, and a lack of adequate resources and prioritisation of tobacco control efforts, leading to slow implementation of the treaty. CONCLUSION: Whilst Ghana has ratified the FCTC, there is an urgent need for action to pass a national tobacco control bill into law to enable it to implement the treaty, sustain tobacco control efforts and prevent Ghana's further involvement in the global tobacco epidemic