Search results for "Clima"

Organic coating on biochar explains its nutrient retention and stimulation of soil fertility

2017

Amending soil with biochar (pyrolized biomass) is suggested as a globally applicable approach to address climate change and soil degradation by carbon sequestration, reducing soil-borne greenhouse-gas emissions and increasing soil nutrient retention. Biochar was shown to promote plant growth, especially when combined with nutrient-rich organic matter, e.g., co-composted biochar. Plant growth promotion was explained by slow release of nutrients, although a mechanistic understanding of nutrient storage in biochar is missing. Here we identify a complex, nutrient-rich organic coating on co-composted biochar that covers the outer and inner (pore) surfaces of biochar particles using high-resoluti…

The importance of environmental microbes for Drosophila melanogaster during seasonal macronutrient variability

2021

AbstractExperiments manipulating the nutritional environment and the associated microbiome of animals have demonstrated their importance for key fitness components. However, there is little information on how macronutrient composition and bacterial communities in natural food sources vary across seasons in nature and on how these factors affect the fitness components of insects. In this study, diet samples from an orchard compost heap, which is a natural habitat for many Drosophila species and other arthropods, were collected over 9 months covering all seasons in a temperate climate. We developed D. melanogaster on diet samples and investigated stress resistance and life-history traits as w…

Importance des récentes variations pluviométriques à Djibouti et besoins de quantification de leurs impacts

2014

Ces dernières décennies, l’Afrique de l’Est souffre d’une longue et lente détérioration pluviométrique. De 2007 à 2011, la ville de Djibouti a enregistré un déficit de 73% des précipitations moyennes annuelles par rapport à la moyenne de 30 ans (1981-2010). Pour caractériser la sécheresse actuelle, nous analysons une série pluviométrique reconstruite pour Djibouti-Ville de 1901 à 2013, les données de terrain permettant d’illustrer les impacts de ces variations pluviométriques. Les précipitations enregistrées à Djibouti ne présentent aucune tendance sur le long terme (1901-2013). Par contre, ces dernières années montrent une très grande variabilité: le suivi de la moyenne pluviométrique sur …

Digitalis obscura cardenolides. Effect of macronutrient concentration and N source on growth and productivity of shoot-tip cultures

1997

Abstract Changes in nutrient medium formulation in terms of major salt concentration or N source significantly modified cardenolide production by Digitalis obscura (genotype T4) shoot-tip cultures. A positive correlation between morphogenetic responses, culture growth, and proliferative capacity on one side and metabolite biosynthesis on the other cannot be established. The final stages of microprogation, rooting, and acclimatization of D. obscura were improved by using paclobutrazol.

Reply to comment by C. Morhange, C. Flaux, P.A. Pirazzoli, M.B. Carre on “Holocene Sea level Change in Malta”

2013

The pits of Birzebbugia are located near the present-day mean sea level, and some are partially submerged. They were dated using pottery discovered in an archaeological site close to the coast, dated to the Bronze Age (Zammit, 1928; Abela, 1999). As they have been interpreted as sites for the retting of flax, during their utilization they should have remained dry and the sea could not submerge them. This is the reason why these structures are not directly related to the sea level, as suggested by Biolchi et al. (2011), so they represent an upper limit.

An improvement of June-September rainfall forecasting in the Sahel based upon region April-May moist static energy content (1968-1997)

1999

This study provides statistical evidence that June–September Sahelian rainfall hindcasts currently based on oceanic thermal predictors apprehend more the negative trend than the interannual rainfall variations. Four physically meaningful predictors of June–September Sahel rainfall are first selected through the near-surface April–May information and several experimental hindcasts provided. We then discuss the skills achieved using regression techniques and cross-validated discriminant functions. In that context, 8/11 of the driest seasons and 8/10 of the wettest are correctly predicted. Finally using completely independent training and working periods we show that better and significant hin…

LEADING SECONDARY SCHOOL STUDENTS TO FACE THE DISCIPLINARY, EPISTEMOLOGICAL AND SOCIETAL CHALLENGES OF CLIMATE CHANGE: DESIGN AND ANALYSIS OF MULTI-D…

The scientific community has been debating climate change (CC) for over two decades. In the light of certain arguments put forward by the aforesaid community, the EU has recommended a set of innovative reforms to science teaching, such as incorporating environmental issues into the scientific curriculum, thereby helping to make schools a place of civic education. However, despite these European recommendations, relatively little emphasis is still given to climate change within science curricula. The main goal of the research project described in this thesis is to study if, how and why the scientific contents related to CC could be reconstructed so as to integrate the many dimensions involve…

Core description collected during Oceanographic Survey NextData2013 (12 – 19 September 2013)

2013

Eolian sedimentation in central European Auel dry maar from 60 to 13 ka

2021

AbstractThe climate in central Europe during the last 60 ka is characterized by rapid temperature and moisture changes and strong cold periods (Heinrich events). All these variations are preserved in sediments of marine and also some terrestrial archives. Here we present a continuous, terrestrial sediment record with almost all Greenland stadials and Heinrich events between 60 and 13 ka visible from carbonate roundness of the Eifel Laminated Sediment Archive Dust Stack-20 and CaCO3 data for central Europe. The carbonate roundness data show almost all stadials between 60 and 13 ka. CaCO3 data show a general transport system change with the beginning of Heinrich event 3. Since there are no ca…

A Taphonomic Perspective on Neolithic Beginnings: Theory, Interpretation, and Empirical Data in the Western Mediterranean

2001

The fills of caves and rockshelters generally comprise complex depositional palimpsests, making fine scale chronological resolution extremely difficult. Nevertheless, these settings remain very important in archaeology because they often preserve long records of cultural change. This is true for the initial appearance of food producing economies in the western Mediterranean. The chronologically ambiguous nature of cave and shelter deposits is one of the reasons for the continued debate over the processes responsible for the beginning of the Neolithic in this region. We employ taphonomic studies of the archeofaunal record from Mesolithic and early Neolithic cave and shelter sites in Mediterr…