Migratory Labour from North-Wester Nigeria

Africa ◽  
1957 ◽  
Vol 27 (3) ◽  
pp. 251-261 ◽  
Author(s):  
R. Mansell Prothero
Keyword(s):  
Large Scale ◽  
Source Area ◽  
Dry Season ◽  
Labour Migration ◽  
Agricultural Activity ◽  
Wet Season ◽  
The North ◽  
The People ◽  
Limited Scale ◽  
Opening Paragraph

Opening ParagraphReaders of Africa will be well aware of population migration as a characteristic feature of a continent where movement between one part and another is largely unrestricted as compared with the more settled parts of the world. There is much evidence of large-scale tribal migrations in the past, of the age-old seasonal wanderings of herders, and of recent labour migration to centres of mineral and industrial production, the last particularly in Central and South Africa. Information is more limited concerning the features of labour migration in West Africa at the present day. In general it is thought that migrants leave their home areas, after the harvest at the commencement of the dry season, to seek work elsewhere for a period of from three to six months and then return to take up farming with the commencement of the next rains. The major source area for these migrants is to the north of the tenth parallel where the wet season is concentrated into a period of about four months, thus severely restricting agricultural activity. Cultivation during the dry season is possible only on a very limited scale. There is thus a considerable period of the year when the primary economic activity of the people is not possible. It is logical that they should seek work elsewhere.

Third report on Glossina investigations in Nyasaland

1916 ◽  
Vol 7 (1) ◽  
pp. 29-50 ◽  
Author(s):  
W. A. Lamborn
Keyword(s):  
Large Scale ◽  
Dry Season ◽  
The South ◽  
Glossina Morsitans ◽  
Lake Shore ◽  
The North ◽  
Sandy Ground ◽  
Artificial Breeding

I remained in the proclaimed area till 6th August 1915, then returning to the vicinity of Monkey Bay for the purpose of endeavouring to establish artificial breeding places on a large scale.While in the proclaimed area I took the opportunity of completing my survey of the distribution of Glossina morsitans, especially in the neighbourhood of Rifu and Kuti described by Dr. Shircore (Bull. Ent. Res., v, p. 87) as “primary centres 1 and 2,” which I had been unable to examine last season before the advent of the rains. As in the case of “ centres 3 and 4,” at Nyansato and Lingadzi respectively, I have not been able to find that the fly is sufficiently localised, even when the dry season is far advanced, as to render feasible any attempt to control it by prophylactic clearing of the bush. In the Rifu district there is a range of rocky hills and high ground running more or less parallel to the lake, with corresponding modification of the soil, so that a zone of scrub has sprung up, from half a mile to two miles in width, consisting very largely of thorn bush, among which are a few big trees. Towards the north this gradually dwindles, to be replaced by the borassus palms usually growing in the sandy ground along the Lake shore, and towards the south it gradually widens out and becomes continuous with the Kuti bush some five miles distant. Throughout its whole extent the fly was plentiful.

scholarly journals Large-scale vertical velocity, diabatic heating and drying profiles associated with seasonal and diurnal variations of convective systems observed in the GoAmazon2014/5 experiment

2016 ◽  
Vol 16 (22) ◽  
pp. 14249-14264 ◽  
Author(s):  
Shuaiqi Tang ◽  
Shaocheng Xie ◽  
Yunyan Zhang ◽  
Minghua Zhang ◽  
Courtney Schumacher ◽  
...  
Keyword(s):  
Vertical Velocity ◽  
Large Scale ◽  
Early Morning ◽  
Dry Season ◽  
Diurnal Variations ◽  
Wet Season ◽  
Convective Systems ◽  
Heating Source ◽  
Seasonal And Diurnal Variations ◽  
Eddy Fluxes

Abstract. This study describes the characteristics of large-scale vertical velocity, apparent heating source (Q1) and apparent moisture sink (Q2) profiles associated with seasonal and diurnal variations of convective systems observed during the two intensive operational periods (IOPs) that were conducted from 15 February to 26 March 2014 (wet season) and from 1 September to 10 October 2014 (dry season) near Manaus, Brazil, during the Green Ocean Amazon (GoAmazon2014/5) experiment. The derived large-scale fields have large diurnal variations according to convective activity in the GoAmazon region and the morning profiles show distinct differences between the dry and wet seasons. In the wet season, propagating convective systems originating far from the GoAmazon region are often seen in the early morning, while in the dry season they are rarely observed. Afternoon convective systems due to solar heating are frequently seen in both seasons. Accordingly, in the morning, there is strong upward motion and associated heating and drying throughout the entire troposphere in the wet season, which is limited to lower levels in the dry season. In the afternoon, both seasons exhibit weak heating and strong moistening in the boundary layer related to the vertical convergence of eddy fluxes. A set of case studies of three typical types of convective systems occurring in Amazonia – i.e., locally occurring systems, coastal-occurring systems and basin-occurring systems – is also conducted to investigate the variability of the large-scale environment with different types of convective systems.

Occurrence of the grasshopper pest Zonocerus variegatus (L.) (Orthoptera: Pyrgomorphidae) in south-western Nigeria in relation to the wet and dry seasons

1980 ◽  
Vol 70 (4) ◽  
pp. 621-633 ◽  
Author(s):  
W. W. Page
Keyword(s):  
Dry Season ◽  
Seasonal Abundance ◽  
Secondary Peak ◽  
Rapid Decline ◽  
Arid Zones ◽  
Zonocerus Variegatus ◽  
Wet Season ◽  
The North ◽  
Dry Seasons ◽  
Peak Abundance

AbstractAn investigation into the seasonal abundance of Zonocerus variegatus (L.) around Ibadan, Nigeria, showed that hatching occurs between October and March and peak abundance is in late November. Adults occur almost throughout the year. Oviposition takes place between March and October or possibly November, with a peak in April. Eggs laid in March and April hatch in October and November after a diapause, while those laid from June onwards do not appear to enter diapause. Thus eggs laid in June and July hatch at the same time as those laid in March and April. Parasitism by the sargophagid fly Blaesoxipha filipjevi (Rod.) during March and April results in a rapid decline in adult numbers which may be followed by a secondary peak in adult numbers when nymphs, which are present at the same time and are rarely parasitised, reach adult stage. Oviposition resulting from such a peak does not produce a secondary peak in hatching as this coincides with hatching from earlier layings. The fungus Entomophthora grylli plays an important role in controlling the abundance of nymphs and adults during the dry season despite the intermittent nature of the attacks. During the wet season, the fungus is able to germinate and disperse more readily, thus keeping the numbers of the insects low. It is concluded that there is one generation of Z. variegatus a year, with a peak in population coinciding with the dry season (November-March). It is suggested from the results that the grasshopper may have originated in the semi-arid zones of the north.

scholarly journals 'The worst disaster suffered by the people of Scotland in recorded history': climate change, dearth and pathogens in the long 14th century

2015 ◽  
Vol 144 ◽  
pp. 223-244
Author(s):  
Richard Oram
Keyword(s):  
Cultural Change ◽  
Large Scale ◽  
Environmental Data ◽  
Historical Discourse ◽  
Proxy Records ◽  
The North ◽  
Political Upheaval ◽  
The People ◽  
Large Scale Change

Informing historical and archaeological discourse with environmental data culled from documentary and climate proxy records is transforming understanding of political, social economic and cultural change across the North Atlantic and European Atlantic regions generally. Limited record evidence and region-specific proxy data has hindered engagement by historians of medieval Scotland with the exploration of environmental factors as motors for long term and large scale change and adoption of the interdisciplinary methodologies involved in their use. This paper seeks to provide an overview of the potential for such data and methodologies in providing context for the well-rehearsed narratives of political upheaval and socio-economic realignment that have characterised much past Scottish historical discourse.

scholarly journals Large-Scale Vertical Velocity, Diabatic Heating and Drying Profiles Associated with Seasonal and Diurnal Variations of Convective Systems Observed in the GoAmazon2014/5 Experiment

2016 ◽  
Author(s):  
Shuaiqi Tang ◽  
Shaocheng Xie ◽  
Yunyan Zhang ◽  
Minghua Zhang ◽  
Courtney Schumacher ◽  
...  
Keyword(s):  
Vertical Velocity ◽  
Large Scale ◽  
Early Morning ◽  
Dry Season ◽  
Diurnal Variations ◽  
Wet Season ◽  
Convective Systems ◽  
Heating Source ◽  
Seasonal And Diurnal Variations ◽  
Eddy Fluxes

Abstract. This study describes the characteristics of large-scale vertical velocity, apparent heating source (Q1) and apparent moisture sink (Q2) profiles associated with seasonal and diurnal variations of convective systems observed during the two intensive operational periods (IOPs) of the Green Ocean Amazon (GoAmazon2014/5) experiment, which was conducted near Manaus, Brazil in 2014 and 2015. The derived large-scale fields have large diurnal variations according to convective activity in the GoAmazon region and the morning profiles show distinct differences between the dry and wet seasons. In the wet season, propagating convective systems originating far from the GoAmazon region are often seen in the early morning, while in the dry season, they are rarely observed. Afternoon convective systems due to solar heating are frequently seen in both seasons. Accordingly, in the morning, there is strong upward motion and associated heating and drying throughout the entire troposphere in the wet season, which is limited to lower levels in the dry season. In the afternoon, both seasons exhibit weak heating and strong moistening in the boundary layer related to the vertical convergence of eddy fluxes. A set of case studies of three typical types of convective systems occurring in Amazonia – i.e., locally-occurring systems, coastal-occurring systems and basin-occurring systems – is also conducted to investigate the variability of the large-scale environment with different types of convective systems.

The Dabona Cemetery in Xiangyun County, Yunnan

2016 ◽  
Vol 16 (1) ◽  
pp. 13-26
Keyword(s):  
Large Scale ◽  
Erhai Lake ◽  
Warring States Period ◽  
Social Situations ◽  
The West ◽  
Warring States ◽  
The North ◽  
Lake Region ◽  
The People ◽  
The Social

Abstract In 2014, Yunnan Provincial Institute of Cultural Relics and Archaeology and other institutions conducted large-scale excavation to the Dabona Cemetery located in Dabona Village and to its east of the Liuchang Town, Xiangyun County. The west zone of the Dabona Cemetery had widely distributed early cultural remains, including house foundations, postholes, ash pits, ash ditches, etc. The east zone consisted of two sections distributed in the north-south direction, in the north section of which 25 burials were recovered; among these burials, six were large-sized ones with lengths more than 6m, and the other were medium- and small-sized burials. The grave goods unearthed from these burials reflected that the dates of the remains and burials were roughly in the Warring-States Period to the Qin and Han Dynasties. The area where these remains and burials were located was the main inhabited area of the people of Kunming ethnic group; this excavation provided important materials for the researches on the features and the social situations of the bronze cultures in the Erhai Lake region.

Growth Strategies of Eucalyptus camaldulensis Dehnh. At Three Sites in Northern Australia

1994 ◽  
Vol 21 (5) ◽  
pp. 653 ◽  
Author(s):  
A Gibson ◽  
EP Bachelard ◽  
KT Hubick
Keyword(s):  
Gas Exchange ◽  
Shoot Growth ◽  
Eucalyptus Camaldulensis ◽  
Dry Season ◽  
Growth Strategies ◽  
Wet Season ◽  
Wind Speeds ◽  
The North ◽  
Air Temperatures ◽  
Semi Arid

The morphology and physiology of trees of Eucalyptus camaldulensis growing in the field at two monsoonal and one semi-arid location were compared. In the wet season, shoot growth at the monsoonal locations was similar and larger than that at the semi-arid location. In the dry season, new shoot growth at the more humid monsoonal location (Petford) was similar to growth in the wet season while at the less humid (Katherine) and the semi-arid (Tennant Creek) locations, shoot growth was foreshortened and the leaves had larger dry weights per unit area. In the summer wet season, leaves on both the north and south sides of the trees were maintained at or below (by up to 5�C) air temperatures throughout the day except for north facing leaves at Petford which were consistently above (by up to 3�C) air temperatures. Midday gas exchange in the dry season at both monsoonal localities was restricted to trees at the water's edge, whereas most trees, including those at drier sites, at the semi-arid location exhibited significant rates of gas exchange. The results, which are discussed in relation to environmental variables (vapour pressure deficits, wind speeds) to which the trees are exposed, and to previous results obtained in the glasshouse, indicate that the differences in shoot growth and physiology are adaptations to the environment in which the trees have evolved.

The Ohu System of Slavery in a Northern Ibo Village-group

Africa ◽  
1954 ◽  
Vol 24 (4) ◽  
pp. 311-336 ◽  
Author(s):  
W. R. G. Horton
Keyword(s):  
Average Density ◽  
North East ◽  
The North ◽  
The People ◽  
District Officer ◽  
North Eastern ◽  
Slave Traders ◽  
History Of ◽  
Opening Paragraph ◽  
The Village

Opening ParagraphThe village-group of Nike occupies an area of some 200 square miles to the immediate north-east of Enugu, capital of the Eastern Provinces of Nigeria. It comprises 24 villages with a total population of 9,600, a figure which gives the average density of the group as 48 per square mile—one of the lowest in Ibo country.Traditions in neighbouring groups, as well as in Nike itself, affirm that before the advent of the British Administration the people of Nike were the principal slave-traders in northern Ibo-land. The first mention of the group in the history of colonial Nigeria appears in an account submitted by the Assistant District Officer, Obubra, of some exploratory journeys undertaken amongst the northern Ibo in the year 1905. Remarking, with the true empire-builder's sang-froid, that ‘the whole area seems relatively quiet and well-disposed…cannibalism and human sacrifice are more or less general’, the officer encloses an interesting sketch-map of the north-eastern section of Ibo-land which shows the Nike group to have been the main trading cross-roads of the whole of this area.

scholarly journals Water and Salt Transports in the Hengsha Channel of Changjiang Estuary

2022 ◽  
Vol 10 (1) ◽  
pp. 72
Author(s):  
Rui Ma ◽  
Jianrong Zhu
Keyword(s):  
Water Transport ◽  
Neap Tide ◽  
Spring Tide ◽  
Dry Season ◽  
Changjiang Estuary ◽  
Dynamic Mechanism ◽  
Gradient Force ◽  
Residual Water ◽  
Wet Season ◽  
The North

In a multilevel bifurcated estuary, the channels between the bifurcated branches play important roles in the exchanges of water and salt. In the Changjiang Estuary, the Hengsha Channel (HC) connects the North Channel (NC) and the North Passage (NP). In this paper, based on a two-way nesting unstructured quadrilateral grid, finite-differencing, three-dimensional estuarine and coastal ocean model, the tidal and seasonal variations in the water and salt transports in the HC were simulated, and their dynamic mechanism was analyzed. The residual water and salt transports in the HC both flow southward from the NC to the NP. In wet season, the residual water transport in the HC is 677 m3/s during neap tide and 245 m3/s during spring tide, and the residual salt transport is 0. In dry season, the residual water and salt transports in the HC are 1278 m3/s and 0.38 t/s during neap tide, respectively, and 1328 m3/s and 12.61 t/s during spring tide. Affected by the northerly wind and the southeastward baroclinic gradient force, the water and salt fluxes in dry season are much larger than those in wet season. The dynamic mechanism responsible for the water transport in the HC was numerically simulated and analyzed.

scholarly journals Identifying Functional Flow Linkages Between Stream Alteration and Biological Stream Condition Indices Across California

2022 ◽  
Vol 9 ◽  
Author(s):  
Ryan Peek ◽  
Katie Irving ◽  
Sarah M. Yarnell ◽  
Rob Lusardi ◽  
Eric D. Stein ◽  
...  
Keyword(s):  
Large Scale ◽  
Environmental Flows ◽  
Condition Index ◽  
Benthic Invertebrate ◽  
Dry Season ◽  
Environmental Data ◽  
Biological Assessment ◽  
Wet Season ◽  
Pulse Flow ◽  
Stream Condition

Large state or regional environmental flow programs, such as the one based on the California Environmental Flows Framework, rely on broadly applicable relationships between flow and ecology to inform management decisions. California, despite having high flow and bioassessment data density, has not established relationships between specific elements of the annual hydrograph and biological stream condition. To address this, we spatially and temporally linked USGS gage stations and biological assessment sites in California to identify suitable paired sites for comparisons of streamflow alteration with biological condition at a statewide scale. Flows were assessed using a set of functional flow metrics that provide a comprehensive way to compare alteration and seasonal variation in streamflow across different locations. Biological response was evaluated using the California Stream Condition Index (CSCI) and Algal Stream Condition Index (ASCI), which quantify biological conditions by translating benthic invertebrate or algal resources and watershed-scale environmental data into an overall measure of stream health. These indices provide a consistent statewide standard for interpreting bioassessment data, and thus, a means of quantitatively comparing stream conditions throughout the state. The results indicate that indices of biological stream condition were most closely associated with flow alteration in seasonality and timing metrics, such as fall pulse timing, dry-season timing, and wet season timing. Magnitude metrics such as dry-season baseflow, wet season baseflow, and the fall pulse magnitude were also important in influencing biological stream conditions. Development of ecological flow needs in large-scale environmental programs should consider that alteration to any of the seasonal flow components (e.g., dry-season baseflow, fall pulse flow, wet-season baseflow, spring recession flow) may be important in restructuring biological communities.

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