The indigenous growth towards a cash economy in Africa — A case study of a lacustrine economy in Malawi

Chilwa, an endohreic lake in East Central Africa, lies in a basin peripheral to the developed areas of the Shire Highlands in Malawi. In 1965 the catch of fish accounted for half the estimated catch of Malawi, while the seasonally inundated grasslands sustain 35,000 head of cattle. The receding lake has left a series of terraces favourable to cotton and tobacco production. This study examines the responses of the people in the southern section of the plain to circumstances which could offer an integrated rural economy with the additional advantage of an entry into the money nexus through commercial fisheries.     

Swiches, pulses and grazing in arid vegetation

This paper examines the possible effect of plants of drylands on their own environment and on neighbouring individuals, in particular the potential for positive feedback between individuals and populations. There are many examples both in shrubby desert vegetation and in desert grassland, but it is in the grassland that feedback is especially associated with small rainfall pulses. I suggest that boundaries between grassland and shrubland are likely to be abrupt in space and time because desert grassland vegetation has a more positive reaction to rainfall change and to its own effects on its environment. Grazing has an important part to play in this relationship.     

Comparing tiltmeters for crustal deformation measurement--a preliminary report

A collection of high-precision tiltmeters is being operated at Pinon Flat Observatory, southern California, both to compare instruments and to measure tectonic deformation. We report on 1.2 years of data from four of these: two Michelson-Gale long fluid tiltmeters, one long center-pressure tiltmeter, and a shallow borehole tiltmeter. The three long-base instruments are all located on the same baseline, with a precise leveling line running between their end-monuments. At nontidal frequencies, only the two Michelson-Gale instruments show some coherence (gamma 2 = .3 for periods of 2 to 4 days), while the center-pressure instrument is correlated with air temperature at periods from a few days to a few weeks. The most stable tilt record shows a secular rate of 0.28 mu rad/a, which may be real. Over much longer times, leveling to specially stabilized bench-marks should confirm this. Comparing instruments has identified more and less successful measurement techniques; it appears that low-noise data will most probably be produced only by relatively complex and expensive instruments, though even for these, the operating costs over any reasonable lifetime will exceed the capital cost. Even the best existing sensors must be improved to measure continuous tectonic motions.     

Finding the repeat times of the GPS constellation

Single-epoch estimates of position using GPS are improved by removing multipath signals, which repeat when the GPS constellation does. We present two programs for finding this repeat time, one using the orbital period and the other the topocentric positions of the satellites. Both methods show that the repeat time is variable across the constellation, at the few-second level for most satellites, but with a few showing much different values. The repeat time for topocentric positions, which we term the aspect repeat time, averages 247 s less than a day, with fluctuations through the day that may be as much as 2.5 s at high latitudes.     

Drought in the Sahel

The Sahel region of West Africa is well known as a region of environmental degradation. The reported incidence of desertification has been challenged but persistent and widespread drought is still widely accepted. Drought, defined solely as a function of rainfall, is believed to have commenced in the early 1970s and continued through to the present. It is usually defined as a meteorological phenomenon and standardised rainfall anomalies are employed to indicate the severity of negative departures from the ‘norm’. There are several difficulties with this approach. The period of standardising rainfall has changed from 1931–1960 to 1961–1990 but the impacts on drought occurrence have not been fully determined. The spatial aggregation of rainfall anomalies may mask important local variation and the purely statistical approach to defining drought takes little account of human impact. The first two issues, averaging period and spatial aggregation, are investigated through an analysis of rainfalls in Continental Sahel (Bukina Faso, Mali and Niger). A new classification of drought classes is suggested. Despite the clear evidence of negative rainfall anomalies for rainfalls aggregated across the Sahel region, it is found that the averaging period has a significant impact on our perceptions of the occurrence of what can be considered to be meteorological drought according to the definition employed and that there is significant spatial variation. This revised version was published online in July 2006 with corrections to the Cover Date.     

THE PATTERN OF PROPERTY-TAX EXEMPTIONS IN A METROPOLITAN FISCAL SETTING

The fiscal-disparities approach to understanding the fiscal problems of many older American central cities neglects the role of property-tax exemptions. This paper, grounded in the metropolitan fiscal setting of Onondaga County and Syracuse, New York, outlines an argument that emphasizes the link between property-tax exemptions, city age, and regional centrality. Central cities are seen as suffering from fiscal burdens imposed partly by their growth as regional centers. It is concluded that, when the financial problems of central cities are being examined, these cities should not be treated as fiscal equivalents to other metropolitan political units but that due regard should be given to their particular historical development.     

莫高窟崖顶防沙工程的效益分析

４年防沙实践证明：莫高窟崖顶防沙试验的工程设计构思是正确的，设计依据科学可靠，防护效益显著。对保护石窟和壁画已经起到重要的作用．其具体防护作用是：１）直接控制偏西风向洞窟搬运沙量的９５％左右；２）洞前夜间积沙减少了８０％以上；３）外围栅栏对来自主风向的外侧积沙的侧导率平均为３５％；对内侧积沙的侧导率，在偏东风作用下可达５７．５１％，在偏西风作用下平均为１５．８９％．上述防沙作用均具有明显的季节变化。     

The Asymmetric Border: The United States’ Place in the World and the Refugee Panic of 2018

The year 2018 saw a moral panic in the United States in the media and among many citizens over the treatment of refugees/asylees at the U.S. southern border, particularly the separation and detention of children apart from their parents. This happened in the context of a period in U.S. political history in which “immigration,” without much discernment about different types of immigration, was central to political discourse. In fact, in terms of numbers, there was no immigration crisis at the border. Undocumented migration from Mexico across the southern border of the United States has been in decline for many years, and the irregular movement of people from El Salvador, Guatemala, and Honduras is currently small by historical standards. The only crisis, to which the U.S. panic was a response, has been a human rights crisis. Families and children seeking asylum from horrendous civil‐rights conditions in their countries of origin were criminalized and denied their right to asylum hearings. The panic points both to the extreme politicization of immigration in the United States, particularly since Donald Trump's entry into national politics in 2015, and to popular confusion over categorizing different types of immigrants. But it also raises questions about the nature of the U.S. southern border in relation to the United States’ place in the world. Rather than thinking about the United States as simply the rich destination country of unfortunate people coming from poor origin countries, the refugee panic of 2018 brings into the focus the fact that the United States itself is complicit in the conditions in those countries that produce so many refugees in the first place.