Continuous change in Tanzanian moist forest tree communities with elevation

Although some studies in tropical forests suggest the existence of elevational discontinuities, zones or critical altitudes in floristic composition (briefly reviewed by Lovett 1996) two data sets from the Usambara mountains of Tanzania independently show a continuous elevational change in moist forest large tree communities (Hamilton et al. 1989, Lovett 1996). However, one data set is from the West Usambara mountains (Lovett 1996) and the other is from the East Usambara (Hamilton et al. 1989). The junction of the two data sets at around 1000–1200 m in elevation is regarded as a critical altitude (Lovett 1996), and so neither conclusively prove continuity over the entire elevational range of the forests. The two data sets were collected using the same methodology, the twenty-tree variable-area plotless technique (Hall 1991), and together constitute a transect covering nearly 2 km in elevation. They are combined here to test for continuity in change in forest large-tree communities from lowland to upper montane forest types

The potato murrain on the European continent and the revolutions of 1848

The tale of the Irish Famine, 1845¿1849, following the outbreak of potato late blight, has been told repeatedly, but the parallel story of the Continental Famine, 1845¿1847, has not yet been recorded. The Continental Famine was caused by poor harvests of potatoes, due to the same late blight, but also of grain, due to frost, drought, rust, voles, inopportune rains, floods and hailstorms. The Continental Famine was enhanced by hoarding, speculation, and poor governance. Hunger was followed by infectious diseases. The demographic effects of hunger and diseases are difficult to disentangle. The number of excess deaths due to the Continental Famine cannot yet be determined with any precision, but clearly it approaches that of the Irish Famine. The harvest failures of 1845 and 1846 and the resulting famines came on top of rural pauperisation and urban discontent, and thus contributed to the revolutions of 1848 on the European Continent. The statement `an epidemic of potato late blight caused an epidemic of revolutions¿ is, perhaps, exaggerated but it contains a grain of truth

Magnetic structures in Co---Cr media for perpendicular magnetic recording

High bit densities have been demonstrated in longitudinal as well as in perpendicular magnetic recording. For the latter an area density of more than 12 Gbit/in2 has been obtained in a sputtered Co---Cr---Ta hard disk with a soft magnetic underlayer recorded with a special single pole head. In this paper the role of microstructure and morphology in relation to the compositional separation is discussed. Very sensitive anomalous Hall measurements have been performed from submicron Co---Cr samples to obtain more detail information about the reversal characteristics of the material. The results obtained have been used in our model for micromagnetic simulations. One of the conclusions is that most of the magnetic entities reversing their magnetisations are much smaller than the volume of one Co---Cr column

Tanzanian forest tree plot diversity and elevation

Observed variation in species richness on ecological gradients and between regions has attracted several different explanations. Climatic factors, such as energy availability, precipitation and mean annual temperature, are frequently cited to explain differences in species richness (Wright et al. 1993). The relative amount of variation in these variables may be of importance as well as absolute values (Stevens 1989, 1992). Alternatively, the history of colonization and extirpation have been used to explain regional variation in diversity (Guo et al. 1998; Latham & Ricklefs 1993a, b). Area is an important factor, for example on an elevational gradient the tops of mountains are not only cooler than the bottoms, but they are also much smaller (Rahbek 1997)

Recent aggradation within the Waikato River

Since approximately 130 A.D. the bed of the Waikato River, in its lower reaches, has been raised 20 to 30ft - most likely by an amount closer to the latter figure. This represents an average of about 1ft every 60 years. Of the causal factors discussed, it is concluded that man-caused erosion is the main contributory factor but, as sea level may have been 10ft lower during 130 A.D., a rise of this amount would no doubt be another major cause

Geology of the Hamilton region

This account takes the form of a synopsis which closely follows that prepared for a bulletin entitled "Geology of the Ngaruawahia Subdivision" (Kear and Schofield, in press). Normally such repetition should be avoided but an exception is made in view of delays in publishing the bulletin and of the parochial nature of this first number of the Earth Science Journal

Elevational and latitudinal changes in tree associations and diversity in the Eastern Arc mountains of Tanzania

A total of 200 variable-area plots covering 20 3 ha containing 4000 trees with a basal area of 921 4 m2 were assessed over a combined elevational range of 410-2180 m in the moist forests of three Tanzanian Eastern Arc mountains: West Usambara, Nguru and Udzungwa. Plot data were ordinated on the basis of species presence/absence, frequency and basal area Axis 1 of ordinations based on species presence/absence are correlated with elevation Axis 1 of the frequency-weighted ordination was correlated with elevation in the Nguru and Udzungwa mountains, but plots from the West Usambara showed a rainfall-related discontinuity Axis 1 of the West Usambara basal area-weighted ordination showed evidence of long-term dynamics of Ocotea usambarensis and in the Udzungwa mountains was determined by presence of Parinari excelsa Plot diversity was not correlated with elevation or latitude, but was lower in disturbed, low rainfall or more seasonal forest. Stem density was positively correlated with elevation and was greater on ridge tops than valley sides and valley bottom

Reflexivity in the research process: psychoanalytic observations

This paper highlights what psychoanalysis can add to discussions of reflexivity, by specifically describing how reflexivity is conceptualized and fostered on psychoanalytic observation methods courses at the Tavistock Clinic, London. It is demonstrated that this psychological form of reflexivity is relevant to empirical and conceptual work and shown that it shares interesting parallels with debates about reflexivity in social research methods, while also being able to contribute to discussions of what constitutes reflexivity and what kinds of methods course might facilitate it. Reflexivity is often discussed in relation to a researcher’s empirical work, but this paper argues that reflexivity is equally needed in relation to the academic context in which most research and learning takes place. This paper demonstrates how psychoanalytic approaches to learning stimulate a reflexive relation to empirical and conceptual work and it provides examples of reflexivity from a two year infant observation and a research project on romantic love (involving conceptual and biographical research)

Where do we draw lines: professional relationship boundaries and the child and youth care practitioner

The question of professional relationship boundaries is a poignant one, in light of the many boundary grey-zones that are created by the variety of young people’s needs, practice settings and professional relationship contexts within the field of child and youth care. In order to support practitioners’ development of critical thought and awareness of professional boundaries, this paper applies a professional relationship boundaries conceptual framework to child and youth care work, and the literature is consulted to explore the impacts of boundary violations, influences on individual’s boundaries, cues to indicate blurring boundaries, and key strategies to maintain balanced boundaries

Dating of recent low sea level and Maori rock carvings Ongari Point

A sea level of at least 1.5ft below the present one, and contemporaneous rock carvings have a radiocarbon date of 180±50 years B.P