The ecological life history of the Cape Bulbul

The study of the ecological life history of the Cape Bulbul Pycnonotus capensis was carried out in 20 hectares of coastal dune forest near Port Elizabeth, South Africa. Results from four years 1959 to 1962 are given in detail and only the number of breeding pairs present in 1958 have been used from observations that year. The Cape Bulbul is one of three closely related species of a predominantly tropical family. Intra specific breeding is rare and occurs only where man has altered the habitat. Distribution has altered slightly in 150 years where colonisation has occurred. Several conditions may influence distribution, the species is mainly limited to within winter or all year round zones of rainfall. Population of breeding pairs varies from nine to 19 pairs. It is the commonest species in the area. There is a 25% annual adult mortality with life expectancy of an adult about three years. Competition for food is negligible. Predators concern mainly the nesting cycle. Clutch size which is two or three is not regulated by food supply or population changes. Main changes are due to emigration and immigration which is apparently influenced by density-independent factors

Educating Young Adults in the Conejo Valley to Choose a Godly Spouse

Problem Divorce rates and marital satisfaction rates are similar in both Christian and non-Christian young adults. Yet increases in church attendance, religious commitment and spirituality have been shown to make significant differences in divorce and marital satisfaction rates. However, many young adults have no framework to understand how to choose a potential spouse, or what factors or characteristics are most important in making such a choice. Almost all premarital education is aimed at young adults who have already chosen their spouse, but have no education aimed at understanding what matters most in making this choice. Method A weekend seminar was designed and presented at The Place Adventist Fellowship the weekend of May 19, 2017, that sought to educate young adults on the characteristics most important in a prospective spouse. Thirteen young adults participated in the entire seminar receiving education on developing a biblical framework for marriage. The participants were asked to complete two separate pre-surveys exploring their beliefs regarding characteristics deemed most important in a potential spouse and two identical post-surveys to measure if their beliefs were influenced by the seminar. The results were evaluated using analysis of the numerical data, observations and written reflections by the participants. Results The seminar and data revealed a group of 13 young adults who had received no formal premarital education. They were enthusiastic about learning through biblical education and contemporary research how to best develop a framework for understanding the characteristics most important in a potential spouse, and for themselves as a potential spouse. Throughout the seminar, participants expressed a desire for greater education in this regard. The data indicated they were receptive to the biblical characteristics of “hot, holy and healthy” and the seminar was meaningful in enabling the participants to freely discern what characteristics were truly important to them. Conclusion Based on the participants’ reflections, the seminar experience and the data from the pre- and post-surveys, the seminar did appear to have spiritual and educational value to them. Consequently, further premarital education regarding the characteristics most important in a potential spouse is merited and recommended

The role of climate in determining the ontogeny trends of low Arctic lakes, south-western Greenland

This thesis uses palaeolimnological records to reconstruct Holocene ontogeny trends from four lakes in south western Greenland. The research addresses four hypotheses investigating how Holocene lake ontogeny trends vary under different climatic settings, how long-term changes in ontogeny relate to periods of established climatic change in the region, the similarities between proxies within the lakes and between the lakes, and the role of vegetation in lake ontogeny. The study region occupies the widest ice-free area of south western Greenland and is characterised by a climatic gradient. The area inland and nearer to the ice-margin is arid, receives less precipitation and is warmer relative to the coastal areas. A paired lake approach, using lake records from two inland lakes and two coastal lakes, was adopted to examine the role of climatic setting upon lake development trajectories. Specifically, diatoms were used to reconstruct DI-alkalinity from the lakes using a DI-alkalinity model created from existing training sets in the region (WA Cla model, r2boot = 0.76, RMSEP = 0.28 log alkalinity units), sedimentary pigments to investigate trends in production and sedimentary parameters to reconstruct organic and minerogenic accumulation rates. All four lakes experienced comparable Holocene long-term ontogeny trajectories; maximum alkalinity in the first ~ 1000 cal. year BP of deglaciation followed by maximum production during the peak of Holocene Thermal Maximum (HTM) warming (~7000 -6000 cal. years BP). Following the HTM, all lakes demonstrated oligotrophication and a decline in pH. Vegetation development and catchment stabilisation at the end of the HTM may be important in determining the onset of oligotrophication in vegetated catchments. However, the impact of vegetation development on lake ontogeny cannot be isolated from the changes in the lakes associated with the colder and wetter climate which occurred at the end of the peak HTM warming. The timings of the large transitions in the ontogeny trajectories are comparable with established periods of Holocene climatic variability in the region; climate forcing drives ontogeny in these lakes. However, there are short-term differences between the lakes indicating that lakes have different thresholds of ecological change and may respond differently to the same climate forcing. It is concluded that ontogeny is driven by climate but lakes may respond differently to forcing depending on catchment specific characteristics which can filter out the climate signal or cause climate to influence the lake in a more direct way

Disproportionate mortality of males in a population of springbok (Artiodactyla: Bovidae)

The hypothesis that an imbalanced sex ratio, favouring females, in populations of springbok (Anti-dorcas marsupialis) is the result of disproportionate mortality of males is tested by comparing the sex ratio in a sample of 50 carcasses with that in a population of live springbok from the same geographical area. The results are consistent with this pypothesis. A suggested refinement of the hypothesis is that the disproportionate male mortality falls most heavily on young adult males which are in close association with springbok territories. Possible causes of this age- and sex-linked mortality are discussed

Testing the accuracy of Foti's dental age estimation methods on a London UK sample

Background and aim: Tooth development and eruption are widely used in assessing dental age estimation, and one of the methods in using tooth development and eruption is Foti's method. However, the population used in the original study was French. Therefore, the aim of this study was to test the accuracy of Foti's four dental age estimation regression models against the East London population, mainly of the Bangladeshi and Caucasian ethnicity. These count the number of erupted teeth and tooth germs using a radiograph (Foti 1), absence of a radiograph (Foti 2), maxillary erupted teeth (Foti 3) and mandibular erupted teeth (Foti 4). Methods: The test sample was archived panoramic radiographs of 754 healthy patients aged 6–20 years (380 males and 374 females). The difference between dental and chronological ages was tested using a t-test. The mean absolute difference was also calculated for all models. The most accurate method was defined as the smallest mean difference, smallest standard deviation (SD) and mean absolute difference between dental and chronological ages. Results: Foti model 2 was most accurate with a mean difference of 0.11 years (SD 1.70 years) and a mean absolute difference of 1.33 years. Models 3 (maxillary erupted teeth) and 4 (mandibular erupted teeth) were marginally less accurate, whilst model 1 (radiograph) overestimated age on average by more than 5 years. Conclusion: Our findings show that estimating age using erupting teeth was most accurate using Foti model 2 (least bias)

Prevalence of Moderate to Severe Periodontitis in an 18–19th Century Sample—St. Bride’s Lower Churchyard (London, UK)

The aim of the study was to determine the prevalence of moderate to severe periodontitis in 18–19th century skulls in the St Bride’s Lower Churchyard in London, UK. Materials and methods: A total of 105 adult skulls (66 M: F 39) from the Museum of London collection were examined for evidence of dental disease. The primary method was to measure the presence of moderate to severe periodontitis. Other dental pathologies were recorded such as tooth wear, calculus, and caries. Results: Overall, the prevalence of moderate to severe periodontitis in the sample was 21–24%. Males were observed to be more susceptible to periodontal disease than females. The severity of bone loss in the skull collection also increased with age. There was no significant difference in the amount of calculus deposition when comparing either age or sex. A total of 14% of the individuals in the sample showed signs of smoking. Conclusion: The results of the study indicated that the prevalence of moderate to severe periodontitis in an 18–19th century skull sample was 21–24%, which was higher than in previous studies. This may be due to the lack of basic personal mouth care and professional dental treatment as well as known risk factors such as smoking, stress, low socioeconomic status, and malnutrition