Water level fluctuations in Lake Baringo,Kenya, during the 19th and 20th centuries: Evidence from lake sediments

This article presents a fossil diatom-based, semi-quantitative reconstruction of water level fluctuations for Lake Baringo over the past 200 years as a consequence of climatic variations. A 285 cm long sediment core sample was collected using a Rod-Operated Single-drive Stationary Piston corer. Lake level was inferred using indices based on the proportion of planktonic to benthic diatom taxa (P/B ratio). The sediment archive presented distinct zones dominated by planktonic and benthic diatom flora. An initial transgression in the early 19th century was characterised as a shallow water environment dominated by planktonic Aulacoseira spp. This was a response to extreme drought during the late 18th to early 19th century. Mid-19th century was defined by a high lake stand. The late 19th to early 20th centuries experienced low water level following the widely documented aridity at the time. The mid-20th century was marked by a spectacular rise in water level that coincided with remarkably wet years during the early 1960s and late 1970s. The first decade of the 21st century witnessed widespread changes in water level. The proxy records show that lake ramping and drawdown over the years follow approximately 50-year climatic cycles.     

Pioneers of exfoliative cytology in the 19th century: the predecessors of George Papanicolaou

The purpose of our study was to summarize the knowledge on exfoliative cytology during the 19th century and to track down Papanicolaou's predecessors. A thorough study of texts, medical books and reports, together with a review of the available literature in PubMed, was undertaken. The study of cytological preparations as a diagnostic procedure can be traced back to the work of the famous French microscopist Alfred François Donné. However, the systematic study and the criteria for the diagnosis of malignant cells should be attributed to Johannes Müller. The increasing interest in the cytological examination of various fluids of the human body can be confirmed by a plethora of studies published during this period. By the end of the 19th century, the invention of new techniques in pathology, such as the introduction of cell block techniques, tissue sections and new staining methods which provided the opportunity to study surgical specimens in three dimensions, led to a decrease in the interest in exfoliative cytology, which was re‐discovered by George Papanicolaou almost three decades later.     

The main trends in the palaeodemography of the 7th-18th century population of Latvia

The study represents palaeodemographic research of osteological material of 3304 individuals from the funds of the Anthropological Laboratory of the Institute of History of the University of Latvia in Riga, dating from the 7th to the 18th century AD. Compensated life expectancy at birth is varying between 20.3 and 22.2 years during the research period. Crude mortality has changed between 49.3 and 45% per hundred. In the early period (7th-13th century) there is a significant male prevalence (2.2-1.4); female life expectancy at the age of 20 is on average 6.6 years less than for males. This difference decreases to 5.4 years in the 13th-18th century. According to historical demography, female life span exceeded male only in the 2nd half of 19th century. The palaeodemographic data indicate that in the 7th-18th century, women in Latvia gave birth to a mean of 4-5 children (the figure includes childless women), of whom half, at most 2-2.5, reached reproductive age, on account of high child mortality. The net reproductive rate R0 (the number of descendants per individual of the parents' generation) varies between 1 and 1.25 in the study period. Concerning the completely excavated cemeteries of Lejasbiteni (7th-10h century) and Daudziesi (16th-17th century), it was possible to calculate the size and structure of the populations that had used these cemeteries. They were similar, having 45.3-49.9% of children up to an age of 14 and 24-28% individuals over the age of 30. According to historical demography, radical improvement of the demographic situation in Latvia began in the second half of the 19th century, when the process of demographic transition in Latvia started.     

Iatrogenic molar borings in 18th and early 19th century Native American dentitions

Six iatrogenic dental borings were identified in four individuals of a Native American skeletal collection from an 18th and early 19th century Middle Columbia River burial site. The borings, all in maxillary first molars with severe dental attrition and secondary dentin, demonstrate striated walls and associated periapical alveolar lesions. An ethnographic review of the subsistence pattern during the burial period indicates a diet that is consistent in dental attrition with other riverine fisher-hunter-gathers. Histological changes of dental pulp tissue during the process of attrition may result in dental necrosis. Access into the pulp chamber is a technique used to drain necrotic fluid. A common Euro-American therapeutic dental practice of the 18th and 19th centuries for diseases of the pulp was dental extraction. Multiple dental borings indicate that the practice of molar drilling into the pulp chamber was an effective and independent technique used by the Wishram and Wasco people.     

The biological standard of living in 19th century Mexico and in the American West

During the mid-19th century, the United States acquired Texas and large parts of Mexican territory with the vast Mexican-born population. This paper considers the biological standard of living of the part of this population that was incarcerated in American prisons. We use their physical stature as a proxy for their biological welfare. These data confirm earlier results which showed that adult heights tended to stagnate in Mexico during the late-19th century despite considerable social and political turmoil. While there is some evidence of a decline in height among youth, the decline is slight (<1 cm). As in other 19th century samples, farmers were the tallest. Americans were taller than Mexican prisoners by about 2 cm.     

Using a historical map as a baseline in a land-cover change study of northeast Tanzania

Vegetation data in an early 20th century map from northern Tanzania are presented and discussed for its potential of expanding the analytical time-frame in studies of land-use and land-cover change. The starting point is that much research on land-use and land-cover change suffers from a time-frame bias, caused by limitations in remote sensing data. At the same time, the use of historical maps as a complementary data-set is rather insignificant. Can information in historical maps be used to extend the baseline in land-use and land-cover change studies? The historical context of the vegetation data is evaluated, and as an illustration of its potential for interdisciplinary research on land-cover and ecosystems change, a section of the map is juxtaposed with a recent pollen record specifically addressing the impact of a 'large infrequent disturbance' (LID) event at the end of the 19th century. It is concluded that the vegetation data in the map are not likely to be reflecting an extreme situation due to the LID event. Finally, the historical vegetation data were visually compared with a national 1995 land-cover data set, illustrating the possibility of using the map data as a baseline in land-cover change studies.     

Climate implications of biomass burning since the 19th century in eastern North America

Recent predictions that tropospheric aerosols have counterbalanced greenhouse warming assume aerosol emissions were low before ad 1850 and then increased dramatically with industrialization of the Northern Hemisphere and biomass burning in the Tropics. We assembled the lake sediment record of emissions across northeastern North America, where temperatures are predicted to have been substantially affected by industrial aerosols. Sediment evidence suggests a systematic shift in source and an overall decline in emissions since the 19th century. The geographical shift results from high presettlement emissions from wildfires in the Midwest that collapsed with tillage and fire suppression. Meanwhile, emissions were increasing in the North-east with European settlement. These regional changes produced a shift from the continental interior to the North-east. An overall decline results because decreases in the Midwest more than compensate for increases in the North-east. Results suggest the Central Plains as an important source of emissions in the recent past, consistent with pioneer accounts of dense smoke clouds emanating from prairie in the 19th century. Contrary to recent models that suggest increased 20th century combustion emissions could have offset warming effects of rising greenhouse gases, our data suggest that aerosols could have actually decreased over this interval. Although we cannot directly quantify aerosols from our methods, the emissions of large particles suggest assumptions of 20th century aerosol declines should be reconsidered.     

Archeological evidence of parasitic infection from the 19th century company town of Fayette, Michigan

Archeological deposits from the 19th century company town of Fayette, Michigan were analyzed for evidence of endoparasitic infection in the human population residing in the town between 1867 and 1891. Three privies were associated with upper-income and middle-income neighborhoods; 2 household refuse disposal areas were found in a predominately lower-income immigrant working class neighborhood. Sediment samples from 2 privies associated with dwellings in the middle-income neighborhood were positive for eggs of the human whipworm Trichuris trichiura. The parasite was probably also present among residents of the lower income neighborhood, but the shallow nature of the refuse deposits in that locality precluded preservation of the eggs. Contemporary epidemiologic studies of helminth infections support the belief that T. trichiura may have been a common parasite of 19th century school-age children given the natural inclination of young children to defecate indiscriminately, play freely in the dirt, and eat without washing their hands.     

Phenological dynamics of arrivals and departures on migratory birds in Cracov,Poland, and the environments in the 19th and 20th century

This study presents the results of phenological observations on arrival and departure terms of some migratory birds on the background of the thermal conditions course of Cracov and its vicinity during the 19th and 20th century. On the base of observations carried out in the years 1944–1978 it was found that some migratory birds had a tendency to change their arrival and departure terms. At the end of this period they were noticed to arrive earlier and to depart later than at the beginning. These differences were more marked when compared with data from the 19th century. In the author's opinion these changes observed in the investigated area during the last decades result from a tendency of a warming up of climate in the Northern Hemisphere.Presented at the Eighth International Congress of Biometeorology, 9–14 September 1979, Shefayim, Israel.     

Tree rings as a surrogate for economic stress – an example from the Puna of Jujuy, Argentina in the 19th century

This paper illustrates the use of tree-ring indices as an indicator of economic stress. In the 19th century the rural economy in the Puna of Jujuy, Northwestern Argentina was based on livestock (llamas and sheep), and was heavily dependant on the availability of pasture and water in this arid landscape. In the absence of traditional indicators of socioeconomic stress, we used tree-ring indices from moisture sensitive trees (Juglans australis Griseb. and Polylepis tarapacana Phil.) as a proxy for droughts and their related economic stresses. Examining the relationship between population mortality and ring-width indices allows inferences to be drawn about the relative importance of environmental and sociopolitical factors in determining mortality patterns that contributed to the depopulation of this area in the late 19th century.     

Racial differences in body mass indices of men imprisoned in 19th Century Texas

A limited amount of research has been done on the body mass index values of 19th century Americans. This paper uses Texas prison records to demonstrate that, in contrast to today's distributions, most BMI values were in the normal range. Only 21.5% and 1.2% of the population was overweight or obese, while today comparable figures are 36% and 23%. There was also little change in BMI values between 1876 and 1919. Farmers were consistently heavier than non-farmers, while Southwestern men had lower BMI values than their counterparts from other regions of the US. BMI values indicate that 19th century African-Americans, and whites populations were well fed in spite of large expenditures on energy.     

Age estimation by dental attrition in an independently controlled early 19th century sample from Zwolle, The Netherlands

This paper reports the investigation of macroscopic aging methods in a skeletal sample from the early 19th century, excavated in The Netherlands and containing a number of individuals of known age and sex. A method is proposed for calibrating age estimations based on dental attrition.     

Rejuvenating old fluorophores with new chemistry

The field of organic chemistry began with 19th century scientists identifying and then expanding upon synthetic dye molecules for textiles. In the 20th century, dye chemistry continued with the aim of developing photographic sensitizers and laser dyes. Now, in the 21st century, the rapid evolution of biological imaging techniques provides a new driving force for dye chemistry. Of the extant collection of synthetic fluorescent dyes for biological imaging, two classes reign supreme: rhodamines and cyanines. Here, we provide an overview of recent examples where modern chemistry is used to build these old-but-venerable classes of optically responsive molecules. These new synthetic methods access new fluorophores, which then enable sophisticated imaging experiments leading to new biological insights.     

Theory and practice: the impact of Mendelism on agriculture

The purpose of this paper is a reexamination of the success story of how Mendelian genetics gave birth to a revolution in plant and animal breeding which produced the spectacular 20th century agricultural progress and made it possible to feed the exploding population of the Earth. Critics have pointed to the problematic social effect of the agricultural revolution, and they have doubted the importance of the new genetics, especially during the first three or four decades of the 20th century. This paper argues that the criticism has tended to take a narrow instrumental view of science underestimating the guiding role of theory in practical matters. Plant and animal breeding continued to depend mainly on the old 19th century techniques, hybridization, mass selection and individual selection. But they were combined and used in much more efficient ways than before. New theoretical knowledge, general theories as well as particular knowledge about species, strains and individuals, radically improved the planning and execution of breeding work.     

The experiments with laboratory animals from a bioethical point of view--history, modern time, perspectives

The origin of laboratory animal science was called forth by violent development of experimental biology and medicine in the XIX century on the one hand, and on the other hand by the necessity to have standard healthy animals for experiments with strictly definite biological characteristics. With this aim in view management technology and animal use in experiments have been constantly improved. "Laboratory animal" notion has been formed by the end of the XIX century. At the beginning of laboratory animal science development ethical problems were not as urgent as they are now. It is established that the three Rs bioethical conception of W.M.S. Russel and R.L. Burch (1959) has influence on modern state and perspectives of the development of animal experimental methods. It is shown that the existence of laboratory animal protection laws and the reflection in them of compulsory ethical review of scientific project and statistics of used laboratory animals is absolutely necessary.     

A cephalometric comparison of skulls from different time periods--the Bronze Age, the 19th century and the present

The aim of this study was to evaluate secular trends by means of orthodontic measurements on lateral cephalograms. We use roentgenograms from three populations: 22 Bronze Age skulls from a cemetery near Hainburg/Austria, 140 soldiers who served in the Hapsburg Imperial Army in the late 19th century, and 154 contemporary recruits of the Austrian Federal Army. Using conventional morphometric analysis, no statistically significant differences could be established. But applying geometric morphometrics to the 2D-coordinates of the pentagon composed of the landmarks Sella, Nasion, Articulare, Gonion and Menton, some biologically interpretable differences were detected, the size allometry between the 19th- and 20th-century populations being the only notable one. We conclude that landmarks should be digitized directly (and many more of them) and that conventional methods used in clinical orthodontics are inappropriate for addressing the scientific questions approached here.     

Animal cognition: 1900-2000

During the 20th century there has been considerable progress in the study of animal cognition, based on essential ideas that were developed earlier. These essential ideas include the metaphors of the animal, the questions, the sources of hypotheses, and the types of explanations. The progress cannot be generally characterized as continuous improvement, cyclic changes, or discrete steps, but the quality of the empirical results has increased substantially since the first experiments in the field. Improvements in research methods have been primarily responsible for this progress. These have included improvements in animal husbandry, stimulus control, apparatus design, the measurement of behavior, experimental procedures, and data analysis. In the last third of the century the computer has led to major improvements in all stages of the research process in animal cognition. Although they have greatly improved the quality of the empirical results, they have not led to a general theory of animal cognition. In the near future the available research methods are likely to lead to further progress in the developments of quantitative theories of animal cognition.     

Associative effects between forages on feed intake and digestion in ruminants

The feeding value of forage mixtures from permanent and temporary multi-species grasslands cannot always be precisely defined. Indeed, the digestibility and feed intake of a combination of forages can differ from the balanced median values calculated from forages considered separately. In order to present an overview of the associative effects between forages on digestion and intake, a literature study was carried out. The associative effects can be studied in a complementary way in vitro to test digestive interactions of a large number of mixtures and to carry out explanatory experiments, and in vivo to investigate intake and digestion at the whole animal scale. We identified three main situations in which interactions between forages can lead to associative effects on intake and digestion: (i) increased intake that can be observed with grass and legume association can be explained by fast digestion of the soluble fraction of legumes, and a higher rate of particle breakdown and passage through the rumen, (ii) increased digestion when a poor forage is supplemented by a high nitrogen content plant can be explained by stimulation of the microbial activity and (iii) modification of digestive processes in the rumen, including proteolysis and methane production when certain bioactive secondary metabolites such as tannins, saponins or polyphenol oxidase are present. According to the type and concentration of these compounds in the diet, the effects can be favourable or unfavourable on intake and digestive parameters. Reported associative effects between forages show a large variability among studies. This reflects the complexity and multiplicity of nutritional situations affecting intake and the rumen function in a given animal. In order to provide more reliable information, further accumulation of data combining in vitro and in vivo studies is required. A better understanding of the associative effects between forages could help to optimise feed use efficiency, resulting in greater productivity, a reduction of the environmental impact of animal emissions and more sustainable animal production.     

An attempt at the historical reconstruction of the genetic demographic structure of the Moscow population at the turn of the 20th century]

The genetic demographic structure of the Moscow population at the turn of the 20th century was studied based on the data from parish books and census records. The main sources of population gene pool replenishment were analyzed, and migration coefficients and the main parameters of the model of isolation by distance were estimated. Data on so-called quasigenetic markers (ethnicity and birthplace) were used to reveal intrapopulation heterogeneity, which facilitates the adaptation of migrants to a new ethnic and cultural environment. The spatial subdivision was analyzed with the use of GST statistics. Muscovites exhibited a considerable positive assortative mating with respect to birthplace. The results of this study provide the necessary historical perspective for predicting the current genetic demographic trends in the Moscow population. It was shown that the co-efficients of marriage migration were almost the same (0.7 < m < 0.8) in the late 19th and mid-20th centuries; however, these values were two times greater than in the late 20th century. This decrease in marriage migration was accompanied by a threefold increase in the radius of centripetal migration and a threefold decrease in the level of isolation by distance. It was determined that the increase in the ethnic and genetic diversity of the Moscow population in the 20th century had started in the 1860s.