New research on the Holocene settlement and environment of the Chad Basin in Nigeria

Recent investigations of three archaeological sites in the Nigerian part of the Chad Basin during the Holocene reveal key stages in the cultural development and environmental history of that region. At Dufuna, a dugout boat was dated to around 6000 BC, making it the oldest known boat in Africa and one of the oldest in the world. Boats may thus have contributed to the mobility of the population of the southern edge of the Sahara 8000 years ago and, thereby, to the cultural homogeneity of this period. The pottery site at Konduga is around a thousand years younger than Dufuna but still belongs to the time of Mega-Chad. The site is on the Bama Ridge, an old shoreline. Its pottery, decorated in the Saharan tradition, belongs to the earliest ceramic phase of the West African Later Stone Age, long before the beginnings of food production. Although this site was probably settled by pioneers advancing into a largely flooded landscape along the slightly raised shoreline, the human occupation of the area previously covered by Mega-Chad began along a broad front around 2000 BC. Archaeological and palaeoecological finds from two settlement mounds at Gajiganna are described as case studies for this phase, which predates the well-known site of Daima.

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Résumé Les résultats présentés proviennent de recherches récentes sur trois sites archéologiques, dont chacun représente un épisode clé du développement culturel et de l'histoire environnementale du Bassin nigérian du Tchad au cours de l'Holocène. A Dufuna, la découverte d'une pirogue monoxyle, datée d'environ 6000 ans BC, constitue le témoignage le plus ancien d'une embarcation en Afrique et l'un des plus ancien dans le monde. Ce moyen de transport indique la mobilité des populations de la marge sud du Sahara à l'Holocène inférieur et moyen; ce qui a dû contribuer à l'homogénéité culturelle de cette période. Le site à poterie de Konduga est le plus jeune d'un millénaire que Dufuna, mais appartient à l'époque du Méga-Tchad. Le site est installé sur une ancienne ligne de rivage, la Bama Ridge. Sa poterie, décorée selon la tradition saharienne, appartient à la plus ancienne phase à céramique du Later Stone Age ouest-africain, bien avant le début d'une production alimentaire. Vu que ce site ne devait étre occupé que par des pionniers aventurés dans un paysage largement amphibie à la faveur d'un mince cordon émergé, la colonisation de l'espace antérieurement couvert par le Méga-Tchad, débute le long d'un large front vers 2000 ans BC.Les trouvailles archéologiques et paléoécologiques de deux tertres anthropiques à Gajiganna sont décrites commes études de cas illustrant cette phase, qui précède celle du célèbre site de Daima.

     

The Links Among Contested Knowledge,Beliefs, and Learning in European Climate Governance: From Consensus to Conflict in Reforming Biofuels Policy

The close link between scientific knowledge, learning, and beliefs is particularly relevant in environmental policymaking and the interaction of environmental with economic development‐focused policies. This article contributes to a more refined understanding of the links among scientific knowledge, belief changes, and the move from a collaborative to an adversarial policy subsystem within the Advocacy Coalition Framework. It analyzes the process of drafting and negotiating the biofuels aspects of the European Renewable Energy Directive, which was dominated by political disagreements between two advocacy coalitions. Their initial agreement on increasing the share of renewable energies in transport turned into conflict after new scientific evidence emerged on the negative environmental and climate change impacts of crop‐based biofuels. The environmental coalition changed its empirical policy beliefs to reflect normative policy beliefs on environmental protection. This change in empirical policy beliefs uncovered a pre‐existing conflict with the normative policy beliefs of the economic development‐focused coalition. As a consequence, the collaborative policy subsystem shifted to an adversarial policy subsystem.     

Ceramic production in ancient Nasca: provenance analysis of pottery from the Early Nasca and Tiza cultures through INAA

We report the results of an instrumental neutron activation analysis (INAA) undertaken on a regional sample of pottery from the Southern Nasca Region. The samples included specimens primarily from the Early Nasca (ca. A.D. 1–450) and Tiza (ca. A.D. 1000–1476) cultures from a total of 16 different prehispanic sites. The results of the analysis demonstrate centralized production of Early Nasca polychromes and decentralized production of pottery from the Tiza culture. The results of this analysis confirm previous conclusions about the organization of these two indigenous cultures of the south coast of Peru and support the hypothesis of an excess production of polychromes at the ceremonial center Cahuachi for Early Nasca, and multiple centers of production for the Tiza culture.     

A charcoal-rich horizon at Ø69, Greenland: evidence for vegetation burning during the Norse landnám?

It is often assumed that the colonisation of Greenland by Norse settlers in c. A.D. 985 had a sudden and dramatic effect on the environment, involving substantial vegetation clearance and environmental degradation. Consequently, it has been argued that charcoal-rich horizons, visible in many sections in Greenland, represent the initial burning of the vegetation by Norse farmers to create land suitable for agriculture. In this study a charcoal-rich layer, visible in a modern drainage ditch beside the Norse farm of Ø69, was analysed using archaeobotany, sedimentary analysis and radiocarbon dating to test the date and formation processes of the horizon. It is demonstrated that the charcoal-rich layer at Ø69 was not derived from in situ vegetation burning in the 10th century and concluded that the layer was probably formed by the addition of midden material to the infields around Ø69 in the 13th and 14th centuries cal AD, perhaps as part of a soil amendment strategy. It is argued that caution must be exercised when interpreting charcoal-rich horizons as time-specific chronological markers in palaeoenvironmental sequences in Greenland.     

The effect of a top predator on kangaroo abundance in arid Australia and its implications for archaeological faunal assemblages

The dingo has received considerable attention in the Australian archaeological literature as an agent of bone fragmentation and accumulation. Dingoes have also been studied with respect to their commensal relationship with Aboriginal people. Study has not been directed, however, to the meta-role of dingoes as prey regulators that suppress kangaroo abundance, and the subsequent impact on human subsistence that direct competition between dingoes and humans over the same animal resources could have produced. This study presents data gathered in two adjacent cultural landscapes defined by human land use, one with dingoes and one without dingoes – to illustrate the archaeological effect that dingoes may have had on human economic systems by suppressing kangaroo abundance. Live kangaroos and kangaroo skeletal remains were on average 14-fold and 32-fold more abundant in the absence of dingoes, and contemporary commercial kangaroo harvesting and sheep grazing were restricted to areas where dingoes were absent. Given the marked effects that dingoes have on contemporary kangaroo abundance and the human economy, we argue that dingoes likely shaped the human economy in the past through human–dingo competition for the same limited resources. Evidence for competition between humans and dingoes could be investigated in the archaeological record by comparing the relative frequency of prey of different body sizes, as well as the degree of fragmentation of kangaroo skeletal elements, before and after the arrival of dingoes.     

The First ‘Urnfields’ in the Plains of the Danube and the Po

Journal of World Prehistory - Archaeological research is currently redefining how large-scale changes occurred in prehistoric times. In addition to the long-standing theoretical dichotomy between...     

The Voting Rights of Incarcerated Australian Citizens

Drawing on and combining political science and legal frameworks, this article explores the validity of disenfranchising Australian prisoners. The authors examine and critically assess the various arguments used in Australia by both legislators and High Court Justices to defend the practice of disenfranchisement. Such arguments are assessed against liberal democratic principles as well as jurisprudence arising from cases in settings that provide protection for electoral rights in formal charters of rights. The authors show that in settings that entrench voting rights in the Constitution, any infringement attracts strict scrutiny from the courts. Courts insist that any abridgement of voting rights should serve a legitimate government purpose and be proportionate to that purpose. The arguments made for prisoner disenfranchisement by legislators in the Australian context invariably fail both parts of this test.     

A Spatial Autoregressive Poisson Gravity Model

In this article, a Poisson gravity model is introduced that incorporates spatial dependence of the explained variable without relying on restrictive distributional assumptions of the underlying data‐generating process. The model comprises a spatially filtered component—including the origin‐, destination‐, and origin‐destination‐specific variables—and a spatial residual variable that captures origin‐ and destination‐based spatial autocorrelation. We derive a two‐stage nonlinear least‐squares (NLS) estimator (2NLS) that is hetero‐scedasticity‐robust and, thus, controls for the problem of over‐ or underdispersion that often is present in the empirical analysis of discrete data or, in the case of overdispersion, if spatial autocorrelation is present. This estimator can be shown to have desirable properties for different distributional assumptions, like the observed flows or (spatially) filtered component being either Poisson or negative binomial. In our spatial autoregressive (SAR) model specification, the resulting parameter estimates can be interpreted as the implied total impact effects defined as the sum of direct and indirect spatial feedback effects. Monte Carlo results indicate marginal finite sample biases in the mean and standard deviation of the parameter estimates and convergence to the true parameter values as the sample size increases. In addition, this article illustrates the model by analyzing patent citation flows data across European regions. En el presente artículo, se introduce un modelo de gravedad Poisson, que incorpora la dependencia espacial de la variable explicada, sin apoyarse en presunciones de distribución restrictivas del proceso subyacente de generación de datos. El modelo comprende de un componente espacialmente filtrado, que incluye las variables de origen, destino y origen‐destino específico; y una variable espacial residual que captura la auto‐correlación espacial basada en el origen y destino. Se deriva del calculador (2NLS) de dos etapas no lineales de mínimos cuadrados (NLS), el cual es robusto en heterocedasticidad, y por ello controla el problema de sobre‐dispersión o baja‐dispersión (over and under dispersion), que a menudo se presenta en el análisis empírico de datos discretos; o, en el caso de de sobre‐dispersión, cuando se presenta la auto correlación espacial. Este calculador puede demostrar tener propiedades deseables para diferentes supuestos distribucionales, como los flujos observados un componente (espacialmente) filtrado, ya sea Poisson o binomial negativo. En nuestra especificación de modelo espacial auto regresivo (SAR), las estimaciones de los parámetros resultantes se pueden interpretar como los efectos de impacto total implícitos, definidos como la suma de efectos espaciales, directos o indirectos, de retroalimentación (feedback). Los resultados Monte Carlo indican sesgos marginales de muestras finitas en la media y la desviación estándar de los parámetros estimados, y la convergencia de los valores de los parámetros reales, a medida que aumenta el tamaño de muestra. Este artículo ilustra el modelo mediante el análisis de flujos de datos de citas de patentes, a través de las regiones europeas. 本文提出了一种蕴含空间依赖的泊松引力模型,该模型中解释变量无需依赖潜在数据生成过程的限制性分布假设。该模型由包含起点、终点、起点‐终点特定变量的空间滤波组分和空间残差变量组成,能捕捉到基于起点和终点的空间自相关。我们推导出一个二阶非线性最小二乘（NLS）估计（2NLS）,它对异方差具有鲁棒性,从而可控制对于离散或过离散数据经验性分析中经常出现的过离散和低离散问题。如果空间自相关存在,过离散数据分析就是一个例子。对于不同的分布假设,如或泊松分布或是负二项式分布的观测流或（空间）滤波组分,该估计量显示出令人满意的性能。在本文的空间自回归（SAR）模型设定中,参数估计结果可解释为隐含的全局影响效应,并可被定义为直接和间接的空间反馈效应之和。蒙特卡罗结果给出了参数估计中均值、标准差的临界有限样本偏差,且随样本量增大收敛于真正参数值。此外,本文基于欧洲地区专利引用的流数据进行了模型验证。