scholarly journals Correlates of Egg Rejection in Hosts of the Brown-Headed Cowbird

The Condor ◽  
2004 ◽  
Vol 106 (3) ◽  
pp. 580-599 ◽  
Author(s):  
Brian D. Peer ◽  
Spencer G. Sealy

AbstractWe conducted a comparative analysis of eight potential correlates of egg rejection in hosts of the parasitic Brown-headed Cowbird (Molothrus ater) to test the evolutionary equilibrium and evolutionary lag hypotheses as explanations for the acceptance of cowbird parasitism. The analyses generally supported evolutionary lag. Historic contact with cowbirds may explain why hosts that have recently come into contact with cowbirds accept parasitism, but it does not account for acceptance by hosts with long histories of contact with cowbirds. Egg predation by hosts, nest sanitation, population size, and egg appearance were not correlated with rejection. Larger species that typically build larger nests were more likely to reject. Large hosts may have been parasitized more frequently in the past, possibly due to their more easily found nests or superiority as hosts, and as a result, may have had more opportunity to evolve rejection. Rejection was also correlated with taxonomic affiliation, suggesting that once rejection evolves it is maintained, which implies that rejection is not costly and thus argues against an evolutionary equilibrium. Not surprisingly, hosts with large bills were more likely to reject. This may be a corollary of the tendency for large hosts, which tend to have larger bills, to reject. An evolutionary equilibrium may exist for hosts with eggs that resemble cowbird eggs, depending on the costs to host reproductive success and the likelihood of committing recognition errors. Nevertheless, some hosts have been in contact with cowbirds for a long time, build large nests, have large bills, have a “favorable” phylogeny, and lay eggs that differ from cowbird eggs, yet accept cowbird parasitism. Chance may play a role in the accumulation of the necessary recombinants and mutations necessary for the evolution of rejection.Factores Correlacionados con el Rechazo de Huevos por parte de Hospederos de Molothrus aterResumen. Realizamos un análisis comparativo de ocho factores que potencialmente podrían estar correlacionados con el rechazo de huevos por parte de hospederos del parásito de cría Molothrus ater para poner a prueba las hipótesis de equilibrio evolutivo y de demora en la respuesta evolutiva propuestas para explicar la aceptación del parasitismo. Los análisis generalmente apoyaron la hipótesis de la demora en la respuesta evolutiva. El contacto histórico con Molothrus podría explicar por qué hospederos que sólo recientemente han entrado en contacto con estas aves aceptan el parasitismo, pero no explica por qué hay hospederos que tienen largas historias de contacto con el parásito y aceptan ser parasitadas. La depredación de huevos por parte del hospedero, el comportamiento de aseo del nido, el tamaño poblacional y la apariencia de los huevos no estuvieron correlacionados con el rechazo de huevos parásitos. Las especies grandes, que típicamente construyen nidos más grandes, presentaron una probabilidad más alta de rechazar huevos. Los hospederos más grandes podrían haber sido parasitados más frecuentemente en el pasado, posiblemente debido a que sus nidos se encuentran con mayor facilidad o a que son mejores hospederos y, como resultado, podrían haber tenido mayores oportunidades evolutivas para desarrollar el comportamiento de rechazar huevos. El comportamiento de rechazo también estuvo correlacionado con la filiación taxonómica, lo que sugiere que una vez que éste evoluciona se mantiene, implicando que no es costoso, lo que a su vez es un argumento en contra de la hipótesis del equilibrio evolutivo. De forma poco sorprendente, los hospederos con picos grandes fueron más propensos a rechazar huevos. Esto podría ser un corolario de la tendencia de los hospederos grandes (los cuales tienden a tener picos más grandes) a rechazar huevos. Es posible que exista un equilibrio evolutivo para los casos de hospederos que tienen huevos que se asemejan a los de Molothrus, dependiendo de los costos sobre el éxito reproductivo del hospedero y la probabilidad de cometer errores de reconocimiento. Sin embargo, algunos hospederos han estado en contacto con Molothrus por períodos prolongados, construyen nidos grandes, tienen picos grandes, tienen afinidades filogenéticas “favorables” y ponen huevos que difieren de los del parásito, y aún así aceptan el parasitismo. El azar podría jugar un papel importante en la acumulación de los recombinantes y mutaciones necesarios para que el comportamiento de rechazo pueda evolucionar.

The Auk ◽  
2002 ◽  
Vol 119 (2) ◽  
pp. 556-560 ◽  
Author(s):  
S. K. Davis ◽  
D. R. Klippenstine ◽  
R. M. Brigham

Abstract We experimentally parasitized Chestnut-collared Longspur (Calcarius ornatus) nests with mimetic and nonmimetic Brown-headed Cowbird (Molothrus ater) eggs to determine whether the low frequency of parasitism reported for that grassland host is due to egg rejection behavior. Longspurs accepted all 23 mimetic eggs (real and wooden) and rejected 9 of 22 blue nonmimetic eggs. Our results suggest longspurs accept cowbird eggs even though they are physically capable of ejecting them from their nest. Thus, the low parasitism frequency reported for that species is not a result of egg rejection behavior, but may be due to antiparasite strategies that reduce their chances of being parasitized (e.g. nest defense behavior).


Entropy ◽  
2021 ◽  
Vol 23 (3) ◽  
pp. 300
Author(s):  
Mark Lokanan ◽  
Susan Liu

Protecting financial consumers from investment fraud has been a recurring problem in Canada. The purpose of this paper is to predict the demographic characteristics of investors who are likely to be victims of investment fraud. Data for this paper came from the Investment Industry Regulatory Organization of Canada’s (IIROC) database between January of 2009 and December of 2019. In total, 4575 investors were coded as victims of investment fraud. The study employed a machine-learning algorithm to predict the probability of fraud victimization. The machine learning model deployed in this paper predicted the typical demographic profile of fraud victims as investors who classify as female, have poor financial knowledge, know the advisor from the past, and are retired. Investors who are characterized as having limited financial literacy but a long-time relationship with their advisor have reduced probabilities of being victimized. However, male investors with low or moderate-level investment knowledge were more likely to be preyed upon by their investment advisors. While not statistically significant, older adults, in general, are at greater risk of being victimized. The findings from this paper can be used by Canadian self-regulatory organizations and securities commissions to inform their investors’ protection mandates.


1994 ◽  
Vol 116 (4) ◽  
pp. 727-732 ◽  
Author(s):  
R. J. Nichols

Development of vehicles to operate on nonpetroleum fuels began in earnest in response to the energy shocks of the 1970s. While petroleum will remain the predominant transportation fuel for a long time, petroleum supplies are finite, so it is not too soon to begin the difficult transition to new sources of energy. In the past decade, composition of the fuel utilized in the internal combustion engine has gained recognition as a major factor in the control of emissions from the tailpipe of the automobile and the rate of formation of ozone in the atmosphere. Improvements in air quality can be realized by using vechicles that operate on natural gas, propane, methanol, ethanol, or electricity, but introduction of these alternative fuel vehicles presents major technical and economic challenges to the auto industry, as well as the entire country, as long as gasoline remains plentiful and inexpensive.


2007 ◽  
Vol 22 (34) ◽  
pp. 2587-2592 ◽  
Author(s):  
PAUL H. FRAMPTON

We address two questions about the past for infinitely cyclic cosmology. The first is whether it can contain an infinite length null geodesic into the past in view of the Borde–Guth–Vilenkin (BGV) "no-go" theorem, The second is whether, given that a small fraction of spawned universes fail to cycle, there is an adequate probability for a successful universe after an infinite time. We give positive answers to both questions and then show that in infinite cyclicity the total number of universes has been infinite for an arbitrarily long time.


2009 ◽  
Vol 33 (4) ◽  
pp. 115-148 ◽  
Author(s):  
Bruce E. Moon

Prospects for democracy in Iraq should be assessed in light of the historical precedents of nations with comparable political experiences. Saddam Hussein's Iraq was an unusually extreme autocracy, which lasted an unusually long time. Since the end of the nineteenth century, only thirty nations have experienced an autocracy as extreme as Iraq's for a period exceeding two decades. The subsequent political experience of those nations offers a pessimistic forecast for Iraq and similar nations. Only seven of the thirty are now democratic, and only two of them have become established democracies; the democratic experiments in the other five are still in progress. Among the seven, the average time required to transit the path from extreme autocracy to coherent, albeit precarious, democracy has been fifty years, and only two have managed this transition in fewer than twenty-five years. Even this sober assessment is probably too optimistic, because Iraq lacks the structural conditions that theory and evidence indicate have been necessary for successful democratic transitions in the past. Thus, the odds of Iraq achieving democracy in the next quarter century are close to zero, at best about two in thirty, but probably far less.


2019 ◽  
Vol 2 (1) ◽  
pp. 8-14
Author(s):  
Beauty Novianty ◽  
Ella Amalia ◽  
Ziske Maritska ◽  
Yuwono Yuwono ◽  
Lusia Hayati

Background: Over the past decade, numbers of Carbapenemase Producing-Carbapenem Resistant Enterobacteriaceae (CP-CRE) has been increasing worldwide and it has been becoming a threat because of its resistance against carbapenem which is considered as the “last resort” antibiotic. Therapy options for its infection are still limited. Aminoglycoside serves as one of the most commonly used antibiotics, but the resistance against it has already been presented for a long time. Aminoglycoside Modifying Enzyme (AME) is the most important resistance mechanism against aminoglycoside. AAC(6’)-Ib enzyme is one of the most common AME produced by the gram-negative bacteria.Objectives: This study wished to identify the gene of this enzyme among CRE isolated from infected Indonesian patients in Dr. Mohammad Hoesin Hospital Palembang.Methods: Twenty-eight isolates collected from CRE-infected patients identified by Vitek 2 Compact (bioMerieux, USA) in dr. Mohammad Hoesin Hospital Palembang during September—November 2017. AAC(6’)-Ib gene was identified using PCR method, then visualize by electrophoresis. The result is then analyzed by comparing it with a susceptibility test.  Results: Out of 28 samples, AAC(6’)-Ib is identified in 22 (78.57%) samples. Samples with AAC(6’)-Ib showed to be less resistant to various antibiotics, significantly to amikacin (p=0.023).Conclusion: AAC(6’)-Ib gene is found in most of samples implying its frequent occurrence in Indonesian patients.


Relevance of the topicofthyroid diseases is duetothein crease in their number in the world and in Ukraine inparticular over the past 5 years, as well as the fact that the total frequency of various forms of thyroid pathology, even outside the zones of endemic goiter, is about 20% of the total morbidity. On the example of a clinical case, the question of diagnostics, management tactics and features of the clinical course of cardiovascular pathology on the background of thyrotoxicosis in the absence of adequate therapy for a long time are considered. Thyrotoxicosis leads to the occurrence of early complications of the cardiovascular system, which determine the further prognosis of the patient’s quality of life. The heart effects of Thyrotoxicosisare most dangerous for the elderly, and they (the heart effects of Thyrotoxicosis) often dominate the clinical picture in them (the elderly). Difficulties in their diagnosis are due, among other things, to the frequent absence of ophthalmopathy. When atrial fibrillation develops, the presence of cardiac symptoms may increase, indicating an accelerated development of heart failure. Therefore, the management of patients with cardiovascular disease on the background of thyrotoxicosis has its own peculiarities, which should be taken into account during treatment.


2021 ◽  
Vol 9 ◽  
Author(s):  
Daniel Hanley ◽  
Samantha L. Rutledge ◽  
Juliana Villa

Hosts of avian brood parasites are under intense selective pressure to prevent or reduce the cost of parasitism. Many have evolved refined egg discrimination abilities, which can select for eggshell mimicry in their parasite. A classic assumption underlying these coevolutionary dynamics is that host egg recognition depends on the perceivable difference between their own eggs and those of their parasite. Over the past two decades, the receptor noise-limited (RNL) model has contributed to our understanding of these coevolutionary interactions by providing researchers a method to predict a host’s ability to discriminate a parasite’s egg from its own. Recent research has shown that some hosts are more likely to reject brown eggs than blue eggs, regardless of the perceived differences to their own. Such responses suggest that host egg recognition may be due to perceptual or cognitive processes not currently predictable by the RNL model. In this perspective, we discuss the potential value of using the RNL model as a null model to explore alternative perceptual processes and higher-order cognitive processes that could explain how and why some hosts make seemingly counter-intuitive decisions. Further, we outline experiments that should be fruitful for determining the perceptual and cognitive processing used by hosts for egg recognition tasks.


2019 ◽  
Vol 19 (3) ◽  
pp. 565
Author(s):  
Elsa Noftalina ◽  
Mayetti Mayetti ◽  
Afriwardi Afriwardi

Stunting is a short body condition based on height according to age (TB / U) whose standard deviation is less than -2 and -3 from the z-score calculation of the WHO child growth standard table. Stunting is an irreversible growth disorder due to inadequate nutrition and recurring infections during the first 1000 days of life. Indicators of chronic malnutrition that occur in a long time so that stunting in children under five, especially at the age of 2-5 years stunting will be clearly visible and is one indicator of chronic nutritional status that can provide an overall picture of the disorder in the past. The causes of stunting are lack of nutrition, infectious diseases, poor parenting, poor environmental sanitation and low health services. Zinc deficiency can cause impaired growth and decreased immunity. One of the biomarkers used is the analysis of hair zinc levels because it can describe chronic zinc levels in the past so it is appropriate to measure zinc levels in the stunting condition which is a long-standing condition of malnutrition. The croos sectional research design was carried out in the Panti District of Pasaman Regency and the West Sumatra Regional Health Laboratory in June to July 2019. The study sample were mothers and children aged 2-5 years as many as 60 people divided into two groups which are stunting and normal children, taken by proportional stratified simple random sampling. Zinc levels were measured by atomic absorption spectrophotometry (AAS) while parenting used questionnaires. Statistical test using Mann Whitney test and Chi Square. The results showed the mean zinc levels in stunting children 154.70 (9-387) µg / g and zinc levels in normal children 241.00 (60-933) µg / g with p = 0.018. parental feeding (p = 0.009), hygiene parenting (p = 0.034). health care parenting (p = 0.017), psychosocial stimulation parenting care (0,000). The conclusion of this study is that there is a significant association between zinc levels and parenting with the incidence of stunting.


Author(s):  
Mohamad Syafiq Mohamad Adenan ◽  
Athirah Nabihah Mas Erwan ◽  
Mohamad Norul Hafiz Muzaffar Alfian

In the past few decades many studies and researches have taken place in order to improve security systems and to increase their level of protection in different fields. One of the major problems that security must deal with is the fire outbreak that can happen in everywhere including houses, schools, factories and many other places, and to avoid that or to minimize the damage caused by fire outbreak an IoT technology is used to control such a kind of risk. IoT is a modern system that consist of sensors and switches connected. In this project we will use temperature sensor known as (Flame sensor) with Arduino device to detect fire outbreak and to measure the amount of heat intensity generated by a fire outbreak or in a specific location in our house, offices and other places. It sometimes takes too much time for the fire station to reach to the fire outbreak location and works on extinguish the fire and so these sensors will work as an early alarm system which will send a notification to our mobile phones if any fire outbreak occurred to let us know the situation clearly and before it’s too late, we act to avoid significant damage in case the fire outbreak was observed after a long time from its outbreak.


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