Childhood conditions,migration, and mortality: Migrants and natives in 19th‐century cities

Abstract

Migrants often have lower mortality than natives in spite of relatively unfavorable social and economic characteristics. Although migrants have a short‐run advantage due to the selective migration of healthy workers, persistent health and mortality differences between migrants and natives may be long‐run effects of different experiences in childhood. We made use of a natural experiment resulting from rural‐to‐urban migration in the mid‐19th century. Mortality was much higher in urban areas, especially in rapidly growing industrial cities. Migrants usually came from healthier rural origins as young adults. Data used in this study is available from 19th‐century Belgian population registers describing two sites: a rapidly growing industrial city and a small town that became an industrial suburb. We found evidence of three processes that lead to differences between the mortality of migrants and natives. First, recent migrants had lower mortality than natives, because they were self‐selected for good health when they arrived. This advantage decreased with time spent in the destination. Second, migrants from rural backgrounds had a disadvantage in epidemic years, because they had less experience with these diseases. Third, migrants from rural areas had lower mortality at older (but not younger) ages, even if they had migrated more than 10 years earlier. We interpret this as a long‐run consequence of less exposure to disease in childhood.     

Avian migrants adjust migration in response to environmental conditions en route

The onset of migration in birds is assumed to be primarily under endogenous control in long-distance migrants. Recently, climate changes appear to have been driving a rapid change in breeding area arrival. However, little is known about the climatic factors affecting migratory birds during the migration cycle, or whether recently reported phenological changes are caused by plastic behavioural responses or evolutionary change. Here, we investigate how environmental conditions in the wintering areas as well as en route towards breeding areas affect timing of migration. Using data from 1984 to 2004 covering the entire migration period every year from observatories located in the Middle East and northern Europe, we show that passage of the Sahara Desert is delayed and correlated with improved conditions in the wintering areas. By contrast, migrants travel more rapidly through Europe, and adjust their breeding area arrival time in response to improved environmental conditions en route. Previous studies have reported opposing results from a different migration route through the Mediterranean region (Italy). We argue that the simplest explanation for different phenological patterns at different latitudes and between migratory routes appears to be phenotypic responses to spatial variability in conditions en route.     

Nice natives and mean migrants: the evolution of dispersal-dependent social behaviour in viscous populations

There has been much interest in the evolution of social behaviour in viscous populations. While low dispersal increases the relatedness of neighbours, which tends to promote the evolution of indiscriminate helping behaviour, it can also increase competition between neighbours, which tends to inhibit the evolution of helping and may even favour harming behaviour. In the simplest scenario, these two effects exactly cancel, so that dispersal rate has no impact on the evolution of helping or harming. Here, we show that dispersal rate does matter when individuals can adjust their social behaviour conditional on whether they have dispersed or whether they have remained close to their place of origin. We find that nondispersing individuals are weakly favoured to indiscriminately help their neighbours, whereas dispersing individuals are more readily favoured to indiscriminately harm their neighbours.     

Interspecific comparison of the performance of soaring migrants in relation to morphology, meteorological conditions and migration strategies

Background

Performance of migrating birds can be affected by a number of intrinsic and extrinsic factors like morphology, meteorological conditions and migration strategies. We compared travel speeds of four raptor species during their crossing of the Sahara desert. Focusing the analyses on this region allows us to compare different species under equivalent conditions in order to disentangle which factors affect migratory performance.

Methodology/Principal Finding

We tracked raptors using GPS satellite transmitters from Sweden, Spain and Italy, and evaluated their migratory performance at both an hourly and a daily scale. Hourly data (flight speed and altitude for intervals of two hours) were analyzed in relation to time of day, species and season, and daily data (distance between roosting sites) in relation to species, season, day length and tailwind support.

Conclusions/Significance

Despite a clear variation in morphology, interspecific differences were generally very small, and did only arise in spring, with long-distance migrants (>5000 km: osprey and Western marsh-harrier) being faster than species that migrate shorter distances (Egyptian vulture and short-toed eagle). Our results suggest that the most important factor explaining hourly variation in flight speed is time of day, while at a daily scale, tailwind support is the most important factor explaining variation in daily distance, raising new questions about the consequences of possible future changes in worldwide wind patterns.     

Timing of autumn bird migration under climate change: advances in long-distance migrants,delays in short-distance migrants

As a response to increasing spring temperature in temperate regions in recent years, populations of many plant and animal species, including migratory birds, have advanced the seasonal start of their reproduction or growth. However, the effects of climate changes on subsequent events of the annual cycle remain poorly understood. We investigated long-term changes in the timing of autumn migration in birds, a key event in the annual cycle limiting the reproductive period. Using data spanning a 42-year period, we analysed long-term changes in the passage of 65 species of migratory birds through Western Europe. The autumn passage of migrants wintering south of the Sahara has advanced in recent years, presumably as a result of selection pressure to cross the Sahel before its seasonal dry period. In contrast, migrants wintering north of the Sahara have delayed autumn passage. In addition, species with a variable rather than a fixed number of broods per year have delayed passage, possibly because they are free to attempt more broods. Recent climate changes seem to have a simple unidirectional effect on the seasonal onset of reproduction, but complex and opposing effects on the timing of subsequent events in the annual cycle, depending on the ecology and life history of a species. This complicates predictions of overall effects of global warming on avian communities.     

Female productivity and mortality in early-20th-century Taiwan

In late-Qing-dynasty Taiwan (1870-1895), female infanticide and general neglect killed over 15% of young girls. During the early years of Japanese rule (1895-1915), female infanticide was almost completely eliminated and the treatment of girls improved. This paper argues that the increase in the willingness to raise daughters was due to an increase in adult female productivity. Under Japanese rule, female seclusion decreased, female labor market participation greatly increased and the custom of foot-binding was ended. These changes increased the expected value of raising a daughter relative to raising a son.     

Enamel hypoplasia and age at weaning in 19th-century Florence,Italy

A sample representing a population of the Florence district of middle 19th century was studied to determine the age of occurrence of enamel hypoplasias. The age interval most affected was that between 1.5 and 3.5 years. Historical sources on weaning habits of 19th-century Italian populations indicate a weaning period between 12 and 18 months. This is in agreement with the data on enamel defects, showing that children of post-weaning age are more subject to stress. Wide “grooves”, with prolonged duration, are concentrated between 2 and 2.5 years, whereas “lines” occur primarily between 2.5 and 3 years. We suggest that this distribution could reflect the gradual introduction of dietary supplements until weaning is complete. © 1994 Wiley-Liss, Inc.     

Two 19th-century chronobiologists: Thomas Laycock and Edward Smith.

This article describes the works of two 19th-century chronobiologists. Thomas Laycock (1812-1876), who held the Chair of Medicine in Edinburgh from 1855-1876, published a series of seven articles in Lancet, all dedicated to periodicities in "vital phenomena." Laycock considered the understanding of periodicities essential for the advancement of the treatment of diseases. Edward Smith (1818-1874) was a pioneer in experimental chronobiology. In his 1861 book entitled: Health and disease as influenced by daily, seasonal and other cyclical changes in the human, Smith summarized a large number of experiments in which he investigated the occurrence of periodicities in pulse rate, urine flow, urea excretion, and respiration. From his experimental results and those of others, Smith drew practical conclusions regarding patients' care, the timing of drug administration, and the design of night work.     

Behavioral and physiological conflicts in migrants: the transition between migration and breeding

Progression of the vernal migratory life history stage to breeding presents a number of apparent behavioral and physiological conflicts. Features that characterize the migratory stage include: high mobility, sociality, repetitive cycles of feeding (hyperphagia and fattening) and migratory flight. Breeding comprises: sedentary, territorial and reproductive behaviors, an initial decline in hyperphagia and reduction of fuel stores. Because morphology, physiology and behavior change, the transition between stages cannot be instantaneous. In many species development of the reproductive system actually occurs during migration, but in others gonadal development may not commence until later. This variation in degree of overlap of migration and reproductive functions is not well understood, but may be related to migratory distance and length of the breeding season, which tends to be shorter at higher latitudes and altitudes. In these habitats, migrants may arrive at their breeding sites to find unpredictable conditions that cannot support breeding. At this juncture, migrants may retreat to refugia and prolong maintenance of facultative migratory functions, termed arrival biology, until conditions improve sufficiently to initiate breeding. In this review, we focus on the Pacific races of the white-crowned sparrow, Zonototrichia leucophyrs, in which the entire spectrum of migratory strategies are represented from resident to long distance migrants and about which much is known. This species presents a unique view of the appearance and variations in arrival biology. Focusing on the juncture between migration and breeding, we discuss the diversity of responses of congeners to a spectrum of environmental conditions that favor survival and reproductive success.     

Childhood cancer mortality in Australia

Aim: To determine current rates of childhood cancer mortality at a national level for Australia and to evaluate recent trends. Methods: Using population-based data from the Australian Paediatric Cancer Registry, we calculated cancer-related mortality counts and rates for the 3-year period 2006-2008 and trends between 1998 and 2008 by sex, age group, and cause of death (defined according to the International Classification of Childhood Cancers, third edition). Rates were directly age-standardised to the 2000 World Standard Population, and linear regression was used to determine the magnitude and significance of trends. The standardised mortality ratio for non-cancer deaths among children with cancer was also estimated. Results: A total of 282 children (23 per million per year) died from cancer in Australia between 2006 and 2008. Large decreases were observed in cancer mortality rates over the study period, particularly for boys (-5.5% per year; p<0.001), children aged 10-14 years old (-5.5% per year; p=0.001), and leukaemia patients (-9.4% per year; p<0.001). However, there was no significant change in mortality due to tumours of the central nervous system. Children with cancer were twice as likely to die from non-cancer causes compared to other children (SMR=2.06; p=0.001). Conclusions: While ongoing improvements in childhood cancer mortality in Australia are generally encouraging, of concern is the lack of a corresponding decrease in mortality among children with certain types of tumours of the central nervous system during the past decade. The results also highlight the need for intensive monitoring of childhood cancer patients for other serious diseases that may subsequently arise.     

Sources of Thought Two 19th-century Chronobiologists: Thomas Laycock and Edward Smith

This article describes the works of two 19th-century chronobiologists. Thomas Laycock (1812-1876), who held the Chair of Medicine in Edinburgh from 1855-1876, published a series of seven articles in Lancet, all dedicated to periodicities in “vital phenomena.” Laycock considered the understanding of periodicities essential for the advancement of the treatment of diseases. Edward Smith (1818-1874) was a pioneer in experimental chronobiology. In his 1861 book entitled: Health and disease as influenced by daily, seasonal and other cyclical changes in the human, Smith summarized a large number of experiments in which he investigated the occurrence of periodicities in pulse rate, urine flow, urea excretion, and respiration. From his experimental results and those of others, Smith drew practical conclusions regarding patients' care, the timing of drug administration, and the design of night work.     

Class discourse in an early 19th-century New England factory

Conclusions While the egalitarian, Republican ring of the 1833 exchange of speeches between Collins and his workers was not a true reflection of the relationship between them, it held sufficient mutual beliefs and desires to be spoken and heard as meaningful. By 1846 the edge of class had sharpened, and language was no longer able to dull it. The speech in 1846 was not successful. There is no record of the workers' language since Collins did not record either their request nor their response—although he copied his own excessively long speech into his memoirs—but we have Collins's word that the speech was not effective, and the men began to leave. According to Collins, in 1846 the circumstances and the men were different.⁶⁵ He might have added that he, also, was different, but it was a statement of the increasing distance between the classes that had not been bridged by the acceptance of hegemonic discourse.According to Wilentz, the shift from Republicanism to a liberal rhetoric of supply and demand was equally unconvincing to New York artisans of this period. While the masters argued that the price of all commodities including labor...were not governed by an engrossing or monopolizing spirit on the part of the landowners or employers but by the limits of supply and demand;⁶⁶ the journeymen argued that the masters' plea that they only followed the laws of supply and demand was a fraudulent ruse, an impudent denial of the best motives of the Revolution and the Constitution.⁶⁷ In fact, this early use of the ideology of independence of the market coincided with an unprecedented involvement of government into the economy.⁶⁸ For the entrepreneurs who invested in and developed the new industries, Republicanism had been an adequate language for surrounding their actions with a patriotic gloss as they gained governmental and public support—financial, legal, and ideological—for private development and profit. It covered class divisions with a cloak of unity. However, the language of Republicanism was potentially inflammatory for workers as well as limiting to the business classes. At Lowell, in 1834, the striking women had circulated a petition grandly composed in Republicanism's rhetoric to protest the tyranny of the workplace: Our present object is to have union and exertion, and we remain in possession of our unquestionable rights. We circulate this paper wishing to obtain the names of all who imbible the spirit of our Patriotic Ancestors, who preferred privation to bondage, and parted with all that renders life desirable and even life itself to procure independence for their children.⁶⁹ Wilentz traces the development of Republicanism in the protests of the New York artisans, who argued that only the journeymen, had the right to judge the value of their labor,⁷⁰ and, even as late as 1850, battled not only specific wages but the wages system itself.⁷¹ At the Collins Company as elsewhere, as management developed more control over labor it spoke a different language. Collins was to some degree restrained by his own prior constructs and experiences. Later generations of employers would have no problem publicly facing their employees and rationalizing exploitation with the bland violence of liberal individualism, telling them that supply and demand was a natural law, self-interest worked to the benefit of all, and since anyone who worked hard could succeed, failure was the fault of the individual. Democracy's place was outside of the workplace after working hours. It was guaranteed by public suffrage and the two-party system.For historians, the recent delineation of Republicanism has led to the understanding that liberal individualism is not just a natural American way to think but a cultural artifact whose beginnings can be traced. The impetus to understand and describe our own world view as a cultural fact has been the increasing inability of liberal individualism to explain or express the economic, social, and political world we live in. By 1846 the class division had become too strongly established for the language of Republicanism to meaningfully bridge it. By 1989 the same could be said for liberal individualism.     

Sources of Thought Two 19th-century Chronobiologists: Thomas Laycock and Edward Smith

This article describes the works of two 19th-century chronobiologists. Thomas Laycock (1812-1876), who held the Chair of Medicine in Edinburgh from 1855-1876, published a series of seven articles in Lancet, all dedicated to periodicities in “vital phenomena.” Laycock considered the understanding of periodicities essential for the advancement of the treatment of diseases. Edward Smith (1818-1874) was a pioneer in experimental chronobiology. In his 1861 book entitled: Health and disease as influenced by daily, seasonal and other cyclical changes in the human, Smith summarized a large number of experiments in which he investigated the occurrence of periodicities in pulse rate, urine flow, urea excretion, and respiration. From his experimental results and those of others, Smith drew practical conclusions regarding patients' care, the timing of drug administration, and the design of night work.