Manipulating parental condition affects brood sex ratio, immunocompetence, and early chick mortality in two gull species differing in sexual size dimorphism

Sex allocation theory predicts that parents should adjust their brood sex ratio to maximize fitness returns in relation to parental investment. Adaptive adjustment of sex ratio may be driven by differential costs of rearing sons and daughters or differential benefits of investing limited resources into offspring of different sex. In both cases, possible sex ratio bias should depend on parental condition. For sexually dimorphic birds with males larger than females, sons may be less likely to fledge since they are more vulnerable to food shortages or because they have impaired immunocompetence due to higher testosterone levels. Poor condition females should thus overproduce daughters to minimize possible reproductive failure. We manipulated the number of eggs laid and the amount of food available to laying females to induce differences in the condition in 2 gull species differing in sexual size dimorphism. In the Black-headed Gull (Chroicocephalus ridibundus), sexual size differences are marginal; but in the Mew Gull (Larus canus), males are 11% larger. In both species, females forced to lay an additional egg (presumed in worse condition) overproduced daughters, whereas females receiving supplemental food before laying (presumed improved condition) overproduced sons. This sex ratio skew was larger in Mew Gull, a species with larger size dimorphism. Chick immunocompetence at hatching was unrelated to sex, being higher in broods of fed mothers and lower for chicks hatched from last-laid eggs. Chick survival between hatching and day 5 post-hatch was positively related to their immunocompetence, but chicks from last-laid eggs and males of Mew Gull, the more dimorphic species, survived less well. Results indicate that costs of raising larger sex offspring coupled with parental condition shape brood sex ratio in populations studied. Adaptive brood sex ratio adjustment occurs mostly before egg laying and includes differential sex allocation in eggs depending on the probability of producing a fledged chick.

Honest signaling in academic publishing

Academic journals provide a key quality-control mechanism in science. Yet, information asymmetries and conflicts of interests incentivize scientists to deceive journals about the quality of their research. How can honesty be ensured, despite incentives for deception? Here, we address this question by applying the theory of honest signaling to the publication process. Our models demonstrate that several mechanisms can ensure honest journal submission, including differential benefits, differential costs, and costs to resubmitting rejected papers. Without submission costs, scientists benefit from submitting all papers to high-ranking journals, unless papers can only be submitted a limited number of times. Counterintuitively, our analysis implies that inefficiencies in academic publishing (e.g., arbitrary formatting requirements, long review times) can serve a function by disincentivizing scientists from submitting low-quality work to high-ranking journals. Our models provide simple, powerful tools for understanding how to promote honest paper submission in academic publishing.

ANALISIS BIAYA DIFERENSIAL DALAM PENGAMBILAN KEPUTUSAN MEMBELI ATAU MEMPRODUKSI SENDIRI PADA RM. MINANG PUTRA

In this era of globalization the economy plays an important role so that competition in the business world is increasingly rapid. In running a business, the management system must be considered carefully in terms of accounting, finance, and decision making aspects. One of them is by making decisions about buying or producing their own raw materials needed to make a product. This study aims to analyze the differential costs in making or buying decisions on their own at RM. Minang Putra. This type of research is quantitative descriptive research that is a method that analyzes the problem by describing it on existing data, in the form of production cost calculation tables to determine the comparison of chicken meat production costs that can provide a clear description or description of the differential cost analysis in buying decision making or produce their own chicken meat at RM. Minang Putra. The results of the study show that the analysis of the differential cost and opportunity cost is very beneficial for RM. Minang Putra in decision making. And a better decision was taken by the RM. Minang Putra is self-producing because the costs incurred are more efficient when compared to buying chickens from outside.

A Cost-minimization Analysis of Provider-to-provider Telemedicine Compared to Usual care in Catalonia: More Agile and Efficient, Especially for Users

Background: Telemedicine (interconsultation between primary and hospital care teams) has been operating in the counties of Central Catalonia Bages, Moianès and Berguedà since 2011 in the specialties of teledermatology, teleulcers, teleeyelids and teleaudiometries. For the period until the end of 2019, a total of 52,198 visits have been recorded. Objective: To analyse the differential costs between telemedicine and usual care in a semi-urban environment. Methodology: A cost-minimization evaluation, including direct and indirect costs from a societal perspective, distinguishing healthcare and user’s costs, within a three-month period. Results: Telemedicine saved € 780,397 over the period analysed. A differential cost favourable to telemedicine of about € 15/visit has been observed, the patient being the largest beneficiary of this saving (by 85%) in terms of shorter waiting times and travel costs. From the healthcare system perspective, moving the time spent in a hospital care consultation to primary care is efficient in terms of the total time devoted per patient. In social terms and in this context, telemedicine is more efficient than usual care. Conclusion: Users’ saving of time in terms of consultation and travel is the main driver of interconsultation between primary and hospital care savings in a semi-urban context. The telemedicine service is also economically favourable for the healthcare system, enabling it to provide a more agile service, which also benefits the healthcare professionals.

The Enemy of My Enemy: When Firms Support Climate Change Regulation

Policies to mitigate global climate change entail significant economic costs. Yet a growing number of firms lobby in favor of regulation to mitigate carbon emissions. Why do firms support environmental regulations that directly increase production costs? This question is all the more puzzling in a globalized economy where regulation may undermine the competitiveness of domestic firms at home and abroad. By imposing differential costs on participants in the domestic market, policies designed to mitigate carbon emissions shift market share toward firms with low anticipated adjustment costs. I develop and test a model of climate change policymaking in the presence of market competition and open borders. Heterogeneity in adjustment costs induces a preference for regulation among low-cost firms. Firms facing import pressure—or export competition—may prefer stringent regulation if costs are sufficiently asymmetric. Firms embedded in global value chains also benefit if regulation raises the costs of domestically produced intermediate goods.

Honest signaling in academic publishing

Academic journals provide a key quality-control mechanism in science. Yet, information asymmetries and conflicts of interests incentivize scientists to deceive journals about the quality of their research. How can honesty be ensured, despite incentives for deception? Here, we address this question by applying the theory of honest signaling to the publication process. Our models demonstrate that several mechanisms can ensure honest journal submission, including differential benefits, differential costs, and costs to resubmitting rejected papers. Without submission costs, scientists benefit from submitting all papers to high-ranking journals, unless papers can only be submitted a limited number of times. Counterintuitively, our analysis implies that inefficiencies in academic publishing (e.g., arbitrary formatting requirements, long review times) can serve a function by disincentivizing scientists from submitting low-quality work to high-ranking journals. Our models provide simple, powerful tools for understanding how to promote honest paper submission in academic publishing.

Achromatic plumage brightness predicts stress resilience and social interactions in tree swallows (Tachycineta bicolor)

Theory suggests that signal honesty may be maintained by differential costs for high and low quality individuals. For signals that mediate social interactions, costs can arise from the way that a signal changes the subsequent social environment via receiver responses. These receiver-dependent costs may be linked with individual quality through variation in resilience to environmental and social stress. Here, we imposed stressful conditions on female tree swallows (Tachycineta bicolor) by attaching groups of feathers during incubation to decrease flight efficiency and maneuverability. We simultaneously monitored social interactions using an RFID network that allowed us to track the identity of every individual that visited each nest for the entire season. Before treatments, plumage coloration was correlated with baseline and stress-induced corticosterone. Relative to controls, experimentally challenged females were more likely to abandon their nest during incubation. Overall, females with brighter white breasts were less likely to abandon, but this pattern was only significant under stressful conditions. In addition to being more resilient, brighter females received more unique visitors at their nest-box and tended to make more visits to other active nests. In contrast, dorsal coloration did not reliably predict abandonment or social interactions. Taken together, our results suggest that females differ in their resilience to stress and that these differences are signaled by plumage brightness, which is in turn correlated with the frequency of social interactions. While we do not document direct costs of social interaction, our results are consistent with models of signal honesty based on receiver-dependent costs.