Elemental XRF analysis carried out on an 8 m long core from the Nile Delta reveals a gradual increase in the Ca/Ti ratio between 5000 and 4000 cal BP which is linked to the progressive development of ...hyper-aridity in this region. The increase results from elevated flux of aeolian material entering the Nile river system from calcareous source rock geologies in the dryer Egyptian Sahara. The most major increase in hyper-aridity occurs around 4000 cal BP. Such a perspective suggests a locally abrupt, regionally time-transgressive inception of hyper-aridity in this region at the end of the African Humid Period. After this time, reorganisation of wind circulation meant that less Saharan-derived aeolian material entered the Nile Valley, and the contribution of aeolian material in the Nile's sedimentary signal was also dwarfed by an increase in Blue Nile sedimentary flux. Chronological control is provided by two radiocarbon dates and the top and bottom of a well-constrained pottery horizon that dates from the period of occupation of two nearby archaeological sites: Kom al-Ahmer and Kom Wasit.
Pearson correlation coefficients between foliar δ13C and mineral elements levels in Sabina przewalskii Kom. Significant correlations are indicated by asterisks: * p < 0.05.
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•δ13C as ...climate proxy is limited by temporal resolution and cost.•Si and δ13C have similar correlations with the climate factors and altitude.•Si content has potential as auxiliary climate indicator.
Stable carbon isotope ratios (δ13C) are widely used as climate proxies for assessing and predicting climatic information at an annual resolution. However, the detailed information in the isotopes that results from intra-annual climate scenarios and is associated with mineral accumulation remains unclear. Combined with investigations of elements and ash contents, variations in foliar δ13C in relation to annual, winter and summer climate scenarios were investigated in a dendroclimatologically important tree species Sabina przewalskii Kom. Foliar δ13C exhibited a significant negative correlation with mean annual temperature, mean annual precipitation and mean annual relative humidity as well as significant positive correlations with elevation. Climatic factors in winter and summer have opposite effects on the variation of δ13C. The beneficial mineral element Si had a significant positive correlation with foliar δ13C, whereas the essential mineral elements K, Ca, and Mg did not. Specifically, Si and δ13C have similar correlations with climate factors and elevation. These results suggest that measurement of Si content has a similar potential to δ13C for use as an alternative climate indicator when detailed climatic information may otherwise be limited and provide a basis for understanding the integration of δ13C in plant responses to climate.
Le besoin de dynamisation d’une langue réside dans l’effet synergique des facteurs sociaux dont certains sont réducteurs ou amplificateurs de la vitalité d’une langue donnée. C’est dans cette logique ...que le présent article se présente la transmission intergénérationnelle et la vitalité de la langue kom. De ce sujet, la problématique qui découle est celle de savoir comment appréhender la transmission intergénérationnelle de la langue kom dans la région du Nord-ouest ? Ainsi, nous avons formulé l’hypothèse selon laquelle le niveau de la transmission de la langue kom peut être mesuré et promu à travers son usage absolu par toutes les souches sociales et ce, dans tous les contextes sociaux. Dans le cadre de ce travail, l’objectif principal est d’évaluer le niveau de transmission intergénérationnelle de la langue kom. Delà, le cadre théorique choisi pour cette étude est la sociolinguistique. Elle a permis d’étudier les interactions entre les hommes dans cette société, leurs comportements, les perceptions et l’organisation des groupes. À travers la recherche documentaire, l’observation directe et le questionnaire nous avons respectivement fixé les bases de cette recherche, de percevoir le comportement de la communauté kom vis-à-vis de sa langue et acquiert les données permettant d’appréhender le niveau de vitalité de cette langue. Les résultats de cette étude montrent que la transmission de la langue kom dans la région du Nord-ouest est quasi totale. Ainsi, il ressort que la vitalité de cette langue est moyenne.
Faunal evidence from the Fayum Neolithic is often cited in the framework of early stock keeping in Egypt. However, the data suffer from a number of problems. In the present paper, large faunal ...datasets from new excavations at Kom K and Kom W (4850-4250 BC) are presented. They clearly show that, despite the presence of domesticates, fish predominate in the animal bone assemblages. In this sense, there is continuity with the earlier Holocene occupation from the Fayum, starting ca. 7350 BC. Domesticated plants and animals appear first from approximately 5400 BC. The earliest possible evidence for domesticates in Egypt are the very controversial domesticated cattle from the 9th/8th millennium BC in the Nabta Playa-Bir Kiseiba area. The earliest domesticates found elsewhere in Egypt date to the 6th millennium BC. The numbers of bones are generally extremely low at this point in time and only caprines are present. From the 5th millennium BC, the numbers of sites with domesticates dramatically increase, more species are also involved and they are usually represented by significant quantities of bones. The data from the Fayum reflect this two phase development, with very limited evidence for domesticates in the 6th millennium BC and more abundant and clearer indications in the 5th millennium BC. Any modelling of early food production in Egypt suffers from poor amounts of data, bias due to differential preservation and visibility of sites and archaeological remains, and a lack of direct dates for domesticates. In general, however, the evidence for early stock keeping and accompanying archaeological features shows large regional variation and seems to be mainly dependent on local environmental conditions. The large numbers of fish at Kom K and Kom W reflect the proximity of Lake Qarun.
•The effect of hydrothermal, NaOH, and EDA pretreatment on CKK was compared.•EDA showed a better de-crystallization effect on CKK compared to other pretreatment.•Addition nutrient in enzymatic ...hydrolysate helps bacterial cellulose (BC) production.•4.6 g/L BC was produced in EDA-pretreated CKK enzymatic hydrolysate.
In this study, three different pretreatment technologies (hydrothermal, NaOH, and ethylenediamine (EDA) pretreatment) were investigated to improve the efficiency of the enzymatic conversion of Caragana korshinskii Kom. (CKK). The effects of the pretreatment conditions on the composition, structure, and enzymatic hydrolysis of CKK were evaluated. The results indicated that EDA pretreatment was more effective in promoting CKK digestibility than the other pretreatments. EDA exhibited a good delignification ability (up to 72.8%) and a strong de-crystallization effect (up to 29.9%) compared to hydrothermal and NaOH pretreatment. The best result for the cellulose enzymatic conversion (88.0%) was obtained at 210 °C for 40 min with 30 mL EDA. Using of the EDA-pretreated CKK as a substrate for bacterial cellulose (BC) production indicated that a lower nutrient level in the enzymatic hydrolysate medium could be a key factor that impedes the fermentation performance of Gluconacetobacter xylinus. The addition of extra nutrients promoted BC production efficiency, and under optimized conditions, the BC yield was 4.6 g/L.
This article discusses a fragment of a model of a tower house found on the surface at Kom el-Gir in the central northwestern Delta. The settlement of Kom el-Gir, which was used at least from the ...Ptolemaic to the Late Roman Periods, showed a dense occupation of tower houses, based on magnetic prospection. A reconstruction of what the house model may have looked like is suggested and the possible uses of such house models are discussed.
Understanding the temporal-spatial variability of tree radial growth and ecological response is the basis for assessing forest vulnerability in sight of climate change. We studied stands of the shrub
...Kom. at four sampling sites (natural forest CL and plantation forests XZJ, CK and TPX) that spanned the different precipitation gradient (180-415 mm) across China's western Loess Plateau, and demonstrated its radial growth dynamics and ecological response. We found that the growth of natural
in arid regions have adapted and cope with regional environmental changes and radial growth was less affected by drought stress. However, the growth of planted
was significantly affected by drought stress in arid and semi-arid regions, especially during the growing season (from June to September). Variations in radial growth rates and growth indicators such as shrub height, canopy area are consistent with the climate-growth relationship. With increase of precipitation, the limiting of drought on the growth of planted
gradually decreased and the amount of radial growth variation explained by drought decreased from 53.8 to 34.2% and 22.3% from 270 to 399 and 415 mm of precipitation, respectively. The age-related radial growth trend shows that radial growth increased until 4 years of age, then decreased rapidly until 12-14 years of age, and then eventually tend to stabilized. In the context of climate warming and humidification, increased precipitation and regular branch coppicing management at around 12 years old will help to mitigate the limitation of drought on the growth of
. Moreover, the initial planting density should be tailored to local precipitation conditions (below 5,000 shrubs per hectare). The above results have important practical significance for the maintenance of the stability and sustainable management of plantation forests in the western Loess Plateau.
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