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The Maghrib has a rich tradition of archaeological studies. However, this research has been biased from the chronological and cultural points of view. This is due to different reasons, relating to both the nature of the archaeological record and the ideological and political circumstances that developed successively under colonial rule and, from the mid-twentieth century, in the modern independent states of the area.
In general, comparatively little attention has been paid to the indigenous cultures of the pre-Roman period, in particular as regards dwelling sites, which generally underlie thick stratigraphic deposits of later periods. The situation is somewhat different with regard to funerary archaeology, as North Africa, especially its eastern portion, is characterised by the existence of a surprising number and diversity of pre-Roman sepulchral monuments.
The previous chapter introduced the Garamantes, an ancient Saharan people, whose story can be traced archaeologically through the first millennium BC and first millennium AD (see also Figs 1.1and 1.2 for location maps). This chapter presents evidence on the funerary practices of the Garamantian heartlands in the Wadi al-Ajal in the Libyan Fazzan (Central Sahara). The Wadi al-Ajal is a long and thin oasis depression running for c.150 km from al-Abyad (to the south-west of Fazzan’s modern capital at Sabha) to Ubari. Our work has been particularly focused on the area around Jarma (ancient Garama, the Garamantian capital about 40 km east of Ubari). The burials in these Garamantian heartlands differ in certain significant ways from those recorded by the Italian mission at Aghram Nadharif and Fewet, and an interesting aspect of the discussion we shall develop below seeks to explain this difference.
Despite more than 150 years of archaeological research in the Maghrib and the Sahara, it is still difficult to establish a universally accepted chronological framework for Moroccan protohistory. While it is generally agreed that its beginning corresponds with the appearance of metal objects around the start of the third millennium BC, its end is much more imprecise, vague and uncertain. The Mediterranean littoral and its hinterland first entered written history around the eighth century BC, at the date of the earliest evidence for a Phoenician presence. However, the other continental regions of Morocco were not part of this schema. These areas were at the margins of ancient knowledge. During the centuries of the ‘Phoenician presence’, only the urban centres changed their character; the countryside, on the other hand, retained a protohistoric lifestyle.
Situated in the hinterland of the eastern Niger Bend in north-east Burkina Faso (Fig. 12.1), in the so-called Gourma area (that is, the bush-land on the right bank of the Niger River), the archaeological site of Kissi consists of an extensive cluster of adjacent settlement areas, including several burial grounds (Fig. 12.2). Its occupation during almost the whole Iron Age (c.third century BC to twelfth century AD) provides the opportunity to follow certain developments that local society underwent over more than a millennium. Spreading over an area of more than 300 hectares, the archaeological site lies on the northern shore of the Mare de Kissi (see Fig. 12.2), a small rainwater-fed lake, similar to – though smaller than – several other lakes in this region (that is, Mare d’Oursi c.35 km to the west, Mare de Darkoy c.6 km to the north, or Mare de Markoye c.15 km to the east, to name but the largest).
The Middle Nile (from Aswan in Egypt to Khartoum in Sudan, Fig. 6.1) is quite exceptional in Sub-Saharan Africa. It is a region where, from the beginning, archaeological frameworks have been constructed largely on the basis of cemetery excavations. This has, of course, much to do with regionally specific research histories and emergent archaeological practices associated with them. The traditions of materially rich mortuary cultures encountered in the Middle Nile, dating back to the early Neolithic period (here the sixth millennium BC), has continued to attract significant archaeological attention. Numerous, often large, cemeteries are still routinely being explored within the context of both research and rescue archaeology. Their material abundance continues to fascinate. The first extensive archaeological survey of Nubia, completed in 1911, excavated more than 8,200 graves in 151 cemeteries within a ‘survey’ area limited to the riverine oasis and covering an area of less than 250 km2.
This ground-breaking volume explores a series of inter-related key themes in Saharan archaeology and history. Migration and identity formation can both be approached from the perspective of funerary archaeology, using the combined evidence of burial structures, specific rites and funerary material culture, and integrated methods of skeletal analysis including morphometrics, palaeopathology and isotopes. Burial traditions from various parts of the Sahara are compared and contrasted with those of the Nile Valley, the Maghreb and West Africa. Several chapters deal with the related evidence of human migration derived from linguistic study. The volume presents the state of the field of funerary archaeology in the Sahara and its neighbouring regions and sets the agenda for future research on mobility, migration and identity. It will be a seminal reference point for Mediterranean and African archaeologists, historians and anthropologists as well as archaeologists interested in burial and migration more broadly.
Visual vertigo is defined as a condition in which there is worsening or triggering of vestibular symptoms in certain visual environments. Previous studies have associated visual vertigo with an increased prevalence of underlying white matter lesions on brain imaging.
This study evaluated the magnetic resonance imaging scans of the brain from a cohort of patients with visual vertigo, and compared the outcomes to an age- and gender-matched group of healthy volunteers.
Results and conclusion
White matter lesions were observed in 17.9 per cent of the patient group and in 16.3 per cent of the control group. The prevalence of white matter lesions in the patient group was not too different to that expected based on age.
Phased Array Feed (PAF) technology is the next major advancement in radio astronomy in terms of combining high sensitivity and large field of view. The Focal L-band Array for the Green Bank Telescope (FLAG) is one of the most sensitive PAFs developed so far. It consists of 19 dual-polarization elements mounted on a prime focus dewar resulting in seven beams on the sky. Its unprecedented system temperature of ~17 K will lead to a 3 fold increase in pulsar survey speeds as compared to contemporary single pixel feeds. Early science observations were conducted in a recently concluded commissioning phase of the FLAG where we clearly demonstrated its science capabilities. We observed a selection of normal and millisecond pulsars and detected giant pulses from PSR B1937+21.
In the framework of the Sardinia Radio Telescope (SRT) Early Science Program, we obtained single-dish high-resolution imaging of the Supernova Remnants IC443 and W44 at 7 GHz. By coupling them with SRT 1.5 GHz maps, we provided spatially-resolved spectral measurements that are highlighting a spread in spectral slope distribution. The observed features range from flat or slightly inverted spectra corresponding to bright radio limbs and filaments, to relatively steep spectra in fainter radio regions. Different theoretical possibilities explaining the above challenging findings are discussed. In particular, we exclude that the observed region-dependent wide spread in spectral slope distribution could be related to absorption processes. Our high-frequency results can be directly related to distinct electron populations in the SNRs including secondary hadronic electrons and resulting from different shocks conditions and/or undergoing different cooling processes. Integrated fluxes associated with the whole SNRs obtained by SRT in comparison with previous results in the literature support the evidence for a slight spectral steepening above 1 GHz for both sources, which could be related to primary electrons or more likely secondary hadronic electrons cut-offs.
We present single-dish imaging of the well-known Supernova Remnants (SNRs) IC443 and W44 at 1.5 GHz and 7 GHz with the recently commissioned 64-m diameter Sardinia Radio Telescope (SRT). Our images were obtained through on-the-fly mapping techniques, providing antenna beam oversampling, automatic baseline subtraction and radio-frequency interference removal. It results in high-quality maps of the SNRs at 7 GHz, which are usually lacking and not easily achievable through interferometry at this frequency due to the very large SNR structures. SRT continuum maps of our targets are consistent with VLA maps carried out at lower frequencies (at 324 MHz and 1.4 GHz), providing a view of the complex filamentary morphology. New estimates of the total flux density are given within 3% and 5% error at 1.5 GHz and 7 GHz respectively, in addition to flux measurements in different regions of the SNRs.
A large fraction of core-collapse supernovae are thought to result in the birth of a rotation-powered pulsar, which is later observable as a radio pulsar up to great ages. The birth properties of these pulsars, and in particular the distribution of their initial rotation periods, are however difficult to infer from studies of the radio pulsar population in our Galaxy. Yet the distributions of their birth properties is an important assumption for scenarios in which ultra-high-energy cosmic rays (UHECRs) originate in very young, extragalactic pulsars with short birth periods and/or high magnetic fields.
Using a model of the very young pulsar wind nebula’s dynamical and spectral evolution, with pulsar wind and accelerated particle parameters assumed similar to those inferred from modeling young pulsar wind nebulae (PWNe) in our Galaxy, we show that X-ray observations of supernovae, a few years to decades after the explosion, constitute a favored window to obtain meaningful constraints on the initial spin-down luminosity of the newly-formed pulsar. We examine the expected emerging PWN spectral component, taking into account the X-ray opacity of the expanding supernova ejecta, and find that it is typically best detectable in < 10 keV X-rays some years after the explosion. We use this framework to assess available X-ray observations and flux upper limits on supernovae, building on the work of Perna et al. (2008). We note that a resulting limit on spin-down luminosity corresponds univocally to a limit on the maximum magnetospheric acceleration potential, irrespective of the specific combination of magnetic field and rotation period that achieves it. We use available X-ray observations of supernovae to place constraints on the birth spin-down luminosity and period distribution of classical pulsars. We also examine the case of magnetars, born with much higher magnetic fields, and show that their much shorter initial spin-down time implies that any plausible signature of young magnetar wind nebulae can only be observed in harder X-ray or gamma-rays.
The distributions of supernovae of different types and subtypes along the radius and in z coordinate of galaxies have been studied. We show that among SNe Ia in spiral galaxies, SNe Iax and Ia-norm have, respectively, the largest and smallest concentration to the center; the distributions of SNe Ia-91bg and Ia-91T are similar. A strong concentration of SNe Ibc to the central regions has been confirmed. In spiral galaxies, the supernovae of all types strongly concentrate to the galactic plane; the slight differences in scale height correlate with the extent to which the classes of supernovae are associated with star formation.
In the framework of the Astronomical Validation and Early Science activities of the Sardinia Radio Telescope (SRT, www.srt.inaf.it), we performed 22 GHz imaging observations of SNR W44 and IC443. Thanks to the single-dish imaging performances of SRT and innovative ad hoc imaging techniques, we obtained maps that provide a detailed view of the structure of the remnants. We are planning to exploit the high-frequency radio data of SNRs to better characterize the spatially-resolved spectra and search for possible spectral steepening or breaks in selected SNR regions, assessing the high-energy tail of the region-dependent electron distribution.