253 research outputs found
A New Group of Middle Kingdom Embalming Deposits? Another look at Pottery Dumps and Repositories for Building Materials in Middle Kingdom Cemeteries
Although mummification is assumed to have been a common practice during the mid-late Middle Kingdom, there are no confirmed examples of so-called âembalming depositsâ â intentional deposits of waste created during the mummification process â from cemeteries of this period. The only Middle Kingdom deposits of this type date to the early Middle Kingdom and come from the Theban necropolis. This paper examines the archaeology of a hitherto overlooked group of intentional cemetery deposits from the mid-late Middle Kingdom and explores the possibility that the deposits might represent an alternative tradition of embalming or deposition of embalming waste
Technologie, Interaktion und Organisation: die Workplace Studies
In den letzten Jahren ist ein Forschungsansatz entstanden, der sich in detaillierten Untersuchungen mit Arbeit, Technologie und Interaktion in komplexen
Organisationen beschÀftigt. Diese Studien, die gemeinhin als "Workplace Studies" bezeichnet werden, entstanden aus den konvergierenden Interessen einerseits in den Bereichen Human-Computer Interaction (HCI), Artificial
Intelligence (AI), Computer Supported Collaborative Work (CSCW), und, auf der anderen Seite, der Konversationsanalyse, der Ethnographie und Àhnlicher
Richtungen in der Soziologie. Da die Workplace Studies hauptsÀchlich mit technischen Disziplinen zusammenarbeiten, sind sie in der Soziologie bislang
noch wenig bekannt. Aus diesem Grunde sollen hier zuerst die HintergrĂŒnde und die Entwicklung der Workplace Studies skizziert werden. Zweitens werden wir die wichtigsten Forschungsgebiete und die methodische Vorgehensweise umreissen. Indem sich die Workplace Studies auf die Frage konzentrieren, wie in den verschiedensten komplexen Organisationen technische Systeme und praktische ArbeitsaktivitĂ€ten miteinander verbunden sind, tragen sie nicht nur zu unserem Wissen ĂŒber Technologie, sondern auch ĂŒber Merkmale der Arbeit in heutigen Organisationen bei. Deswegen möchten wir besonders hervorheben, welchen Beitrag die Workplace Studies fĂŒr die Fragestellung einer Reihe spezieller Soziologien liefern, wie etwa die der Soziologie der Arbeit, der Soziologie der Organisation und der Soziologie der Technik. Die Workplace Studies, so möchten wir zeigen, stellen nicht nur eine Reihe von Ergebnissen zu gegenwĂ€rtig relevanten Themen und Fragestellungen bereit; sie eröffnen ĂŒberdies die Möglichkeit, zentrale Begriffe neu zu fassen, wie etwa Technologie, Arbeitsteilung oder Arbeitsaufgabe ("Task"). Daneben hoffen wir auch zeigen zu können, dass die Workplace Studies ebenfalls interessante Lösungen fĂŒr einige methodologische Probleme der naturalistischen
ForschungsansÀtze geben können
Willingness of farmers to pay for reclaimed wastewater in Jordan and Tunisia.
Despite water scarcity and high agricultural water consumption in the Middle East and North Africa region, substantial amounts of treated wastewater are discharged into seas without proper utilization. This can be attributed to either farmers' unwillingness to use or to pay for reclaimed wastewater. Therefore, a field survey was conducted in Jordan and Tunisia, which are considered as representative to the MENA region, using a prepared and pilot tested questionnaire. This study applies the contingent valuation method to elicit the willingness of farmers to pay for reclaimed wastewater. Logistic regression analysis is applied in an attempt to build a model that correlates qualitative responses of farmers to monetary stimuli. The water price seriously affects farming profitability and farmers' willingness to pay for reclaimed wastewater. Farmers prove to be unwilling to pay more than 0.05 $/m3 of reclaimed wastewater primarily because of quality concerns, comparatively easy access to freshwater, and price
Methane turnover and temperature response of methane-oxidizing bacteria in permafrost-affected soils of northeast Siberia
The abundance, activity, and temperature response of aerobic methane-oxidizing bacteria were studied in permafrost-affected tundra soils of northeast Siberia. The soils were characterized by both a high accumulation of organic matter at the surface and high methane concentrations in the water-saturated soils. The methane oxidation rates of up to 835 nmol CH4 hâ1 gâ1 in the surface soils were similar to the highest values reported so far for natural wetland soils worldwide. The temperature response of methane oxidation was measured during short incubations and revealed maximum rates between 22 °C and 28 °C. The active methanotrophic community was characterized by its phospholipid fatty acid (PLFA) concentrations and with stable isotope probing (SIP). Concentrations of 16:1Ï8 and 18:1Ï8 PLFAs, specific to methanotrophic bacteria, correlated significantly with the potential methane oxidation rates. In all soils, distinct 16:1 PLFAs were dominant, indicating a predominance of type I methanotrophs. However, long-term incubation of soil samples at 0 °C and 22 °C demonstrated a shift in the composition of the active community with rising temperatures. At 0 °C, only the concentrations of 16:1 PLFAs increased and those of 18:1 PLFAs decreased, whereas the opposite was true at 22 °C. Similarly, SIP with 13CH4 showed a temperature-dependent pattern. When the soils were incubated at 0 °C, most of the incorporated label (83%) was found in 16:1 PLFAs and only 2% in 18:1 PLFAs. In soils incubated at 22 °C, almost equal amounts of 13C label were incorporated into 16:1 PLFAs and 18:1 PLFAs (33% and 36%, respectively). We concluded that the highly active methane-oxidizing community in cold permafrost-affected soils was dominated by type I methanotrophs under in situ conditions. However, rising temperatures, as predicted for the future, seem to increase the importance of type II methanotrophs, which may affect methane cycling in northern wetlands
Arctic Nearshore Sediment DynamicsâAn Example from Herschel IslandâQikiqtaruk, Canada
Increasing arctic coastal erosion rates imply a greater release of sediments and organic matter into the coastal zone. With 213 sediment samples taken around Herschel IslandâQikiqtaruk, Canadian Beaufort Sea, we aimed to gain new insights on sediment dynamics and geochemical properties of a shallow arctic nearshore zone. Spatial characteristics of nearshore sediment texture (moderately to poorly sorted silt) are dictated by hydrodynamic processes, but ice-related processes also play a role. We determined organic matter (OM) distribution and inferred the origin and quality of organic carbon by C/N ratios and stable carbon isotopes ÎŽ13C. The carbon content was higher offshore and in sheltered areas (mean: 1.0 wt. %., S.D.: 0.9) and the C/N ratios also showed a similar spatial pattern (mean: 11.1, S.D.: 3.1), while the ÎŽ13C (mean: â26.4â° VPDB, S.D.: 0.4) distribution was more complex. We compared the geochemical parameters of our study with terrestrial and marine samples from other studies using a bootstrap approach. Sediments of the current study contained 6.5 times and 1.8 times less total organic carbon than undisturbed and disturbed terrestrial sediments, respectively. Therefore, degradation of OM and separation of carbon pools take place on land and continue in the nearshore zone, where OM is leached, mineralized, or transported beyond the study area.</jats:p
Deglacial permafrost carbon dynamics in MPI-ESM
We have developed a new module to calculate soil organic carbon (SOC) accumulation in perennially frozen ground in the land surface model JSBACH. Running this offline version of MPI-ESM we have modelled permafrost carbon accumulation and release from the Last Glacial Maximum (LGM) to the Pre-industrial (PI). Our simulated near-surface PI permafrost extent of 16.9Miokm2 is close to observational evidence. Glacial boundary conditions, especially ice sheet coverage, result in profoundly different spatial patterns of glacial permafrost extent. Deglacial warming leads to large-scale changes in soil temperatures, manifested in permafrost disappearance in southerly regions, and permafrost aggregation in formerly glaciated grid cells. In contrast to the large spatial shift in simulated permafrost occurrence, we infer an only moderate increase of total LGM permafrost area (18.3Miokm2) â together with pronounced changes in the depth of seasonal thaw. Reconstructions suggest a larger spread of glacial permafrost towards more southerly regions, but with a highly uncertain extent of non-continuous permafrost.
Compared to a control simulation without describing the transport of SOC into perennially frozen ground, the implementation of our newly developed module for simulating permafrost SOC accumulation leads to a doubling of simulated LGM permafrost SOC storage (amounting to a total of ~150PgC). Despite LGM temperatures favouring a larger permafrost extent, simulated cold glacial temperatures â together with low precipitation and low CO2 levels â limit vegetation productivity and therefore prevent a larger glacial SOC build-up in our model. Changes in physical and biogeochemical boundary conditions during deglacial warming lead to an increase in mineral SOC storage towards the Holocene (168PgC at PI), which is below observational estimates (575PgC in continuous and discontinuous permafrost). Additional model experiments clarified the sensitivity of simulated SOC storage to model parameters, affecting long-term soil carbon respiration rates and simulated active layer depths. Rather than a steady increase in carbon release from the LGM to PI as a consequence of deglacial permafrost degradation, our results suggest alternating phases of soil carbon accumulation and loss as an effect of dynamic changes in permafrost extent, active layer depths, soil litter input, and heterotrophic respiration
Long-term deglacial permafrost carbon dynamics in MPI-ESM
We have developed a new module to calculate soil organic carbon (SOC) accumulation in perennially frozen ground in the land surface model JSBACH. Running this offline version of MPI-ESM we have modelled long-term permafrost carbon accumulation and release from the Last Glacial Maximum (LGM) to the pre-industrial (PI) age. Our simulated near-surface PI permafrost extent of 16.9âĂâ106âkm2 is close to observational estimates. Glacial boundary conditions, especially ice sheet coverage, result in profoundly different spatial patterns of glacial permafrost extent. Deglacial warming leads to large-scale changes in soil temperatures, manifested in permafrost disappearance in southerly regions, and permafrost aggregation in formerly glaciated grid cells. In contrast to the large spatial shift in simulated permafrost occurrence, we infer an only moderate increase in total LGM permafrost area (18.3âĂâ106âkm2) â together with pronounced changes in the depth of seasonal thaw. Earlier empirical reconstructions suggest a larger spread of permafrost towards more southerly regions under glacial conditions, but with a highly uncertain extent of non-continuous permafrost.
Compared to a control simulation without describing the transport of SOC into perennially frozen ground, the implementation of our newly developed module for simulating permafrost SOC accumulation leads to a doubling of simulated LGM permafrost SOC storage (amounting to a total of âŒâ150âPgC). Despite LGM temperatures favouring a larger permafrost extent, simulated cold glacial temperatures â together with low precipitation and low CO2 levels â limit vegetation productivity and therefore prevent a larger glacial SOC build-up in our model. Changes in physical and biogeochemical boundary conditions during deglacial warming lead to an increase in mineral SOC storage towards the Holocene (168âPgC at PI), which is below observational estimates (575âPgC in continuous and discontinuous permafrost). Additional model experiments clarified the sensitivity of simulated SOC storage to model parameters, affecting long-term soil carbon respiration rates and simulated ALDs. Rather than a steady increase in carbon release from the LGM to PI as a consequence of deglacial permafrost degradation, our results suggest alternating phases of soil carbon accumulation and loss as an effect of dynamic changes in permafrost extent, ALDs, soil litter input, and heterotrophic respiration
Prevalence and risk factors of undernutrition among schoolchildren in the Plateau Central and Centre-Ouest regions of Burkina Faso
Multiple factors determine children's nutritional status, including energy and nutrient intake, recurrent infectious diseases, access (or lack thereof) to clean water and improved sanitation, and hygiene practices, among others. The "Vegetables go to School: improving nutrition through agricultural diversification" (VgtS) project implements an integrated school garden programme in five countries, including Burkina Faso. The aim of this study was to determine the prevalence of undernutrition and its risk factors among schoolchildren in Burkina Faso before the start of the project.; In February 2015, a cross-sectional survey was carried out among 455 randomly selected children, aged 8-14 years, in eight schools in the Plateau Central and Centre-Ouest regions of Burkina Faso. Nutritional status was determined by anthropometric assessment. Helminth and intestinal protozoa infections were assessed using the Kato-Katz and a formalin-ether concentration method. A urine filtration technique was used to identify Schistosoma haematobium eggs. Prevalence of anaemia was determined by measuring haemoglobin levels in finger-prick blood samples. Questionnaires were administered to children to determine their knowledge of nutrition and health and their related attitudes and practices (KAP). Questionnaires were also administered to the children's caregivers to identify basic household socio-demographic and economic characteristics, and water, sanitation and hygiene (WASH) conditions. To determine the factors associated with schoolchildren's nutritional status, mixed logistic regression models were used. Differences and associations were considered statistically significant if P-values were below 0.05.; Complete datasets were available for 385 children. The prevalence of undernutrition, stunting and thinness were 35.1%, 29.4% and 11.2%, respectively. The multivariable analysis revealed that undernutrition was associated with older age (i.e. 12-14 years compared to <12 years; adjusted odds ratio (aOR)â=â3.45, 95% confidence interval (CI) 2.12-5.62, Pâ<â0.001), multiple pathogenic parasitic infections (aORâ=â1.87, 95% CI 1.02-3.43, Pâ=â0.044) and with moderate and severe anaemia in children (aORâ=â2.52, 95% CI 1.25-5.08, Pâ=â0.010).; We found high prevalence of undernutrition among the children surveyed in the two study regions of Burkina Faso. We further observed that undernutrition, anaemia and parasitic infections were strongly associated. In view of these findings, concerted efforts are needed to address undernutrition and associated risk factors among school-aged children. As part of the VgtS project, WASH, health education and nutritional interventions will be implemented with the goal to improve children's health.; ISRCTN17968589 (date assigned: 17 July 2015)
Rapid CO2 release from eroding permafrost in seawater
Permafrost is thawing extensively due to climate warming. When permafrost thaws, previously frozen organic carbon (OC) is converted into carbon dioxide (CO2) or methane, leading to further warming. This process is included in models as gradual deepening of the seasonal nonâfrozen layer. Yet, models neglect abrupt OC mobilization along rapidly eroding Arctic coastlines. We mimicked erosion in an experiment by incubating permafrost with seawater for an average Arctic openâwater season. We found that CO2 production from permafrost OC is as efficient in seawater as without. For each gram (dry weight) of eroding permafrost, up to 4.3 ± 1.0 mg CO2 will be released and 6.2 ± 1.2% of initial OC mineralized at 4 °C. Our results indicate that potentially large amounts of CO2 are produced along eroding permafrost coastlines, onshore and within nearshore waters. We conclude that coastal erosion could play an important role in carbon cycling and the climate system
Oxidation kinetics of La and Yb incorporated Zr-doped ceria for solar thermochemical fuel production in the context of dopant ionic radius and valence
The influence of ionic radii and valence of dopants in Ce0.9LaxYbyZr0.1âxâyO2âÎŽ (x = 0, 0.05, 0.1, y = 0, 0.05, 0.1) on the oxidation kinetics were investigated by thermogravimetric analysis in synthetic air and were compared to undoped ceria. Samples co-doped with ZrâLa and ZrâYb exhibited moderate oxidation kinetics that were slower than undoped ceria, but much faster than 10mol% Zr-doped ceria. The extrinsic oxygen vacancy induced by the trivalent dopants improves the kinetics at oxidation temperatures below 700 °C, where the diffusion, and not the surface exchange reaction is the limiting factor. A smaller ionic radius of the substituent (i.e. r(Yb3+) r(La3+)) in the co-doped ceria tends to facilitate lower activation energy resulting in slightly faster oxidation kinetics at temperatures below 700 °C. In contrast, additional extrinsic vacancies are rather obstructive at high temperatures (i.e. T 700 °C) due to a change of rate limiting mechanism from bulk oxygen diffusion to surface exchange reaction. Overall, the valence of the dopant rather than the ionic radius seems to determine the oxidation kinetics primarily, and additional La or Yb doping on Zr-doped ceria is appealing especially when the applications are focused on low temperature reactions
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