274 research outputs found
Neolithic land use in the northern Boreal zone: high-resolution multiproxy analyses from Lake Huhdasjarvi, south-eastern Finland
Two high-resolution pollen and charcoal analyses were constructed from sediments obtained from a small bay in eastern Finland in order to gain information on human activity during the Neolithic Stone Age, 5200-1800 BC. We used measurements of loss on ignition (LOI), magnetic susceptibility and geochemical analyses to describe the sedimentological characteristics. Palaeomagnetic dating and measurements of Cs-137-activity were supported by C-14-datings. The analyses revealed human activity between 4400 and 3200 BC, which is synchronous with archaeological cultures defined through different stages of Comb Ware pottery types and Middle Neolithic pottery types with asbestos as a primary temper. Direct evidence of Hordeum cultivation was dated to 4040-3930 cal BC. According to the pollen data, more significant effort was put into the production of fibres from hemp and lime than the actual cultivation of food
Potential for an underwater glider component as part of the Global Ocean Observing System
The contributions of autonomous underwater gliders as an observing platform in the in-situ global ocean observing system (GOOS) are investigated. The assessment is done in two ways: First, the existing in-situ observing platforms contributing to GOOS (floats, surface drifters, moorings, research/commercial ships) are characterized in terms of their current capabilities in sampling key physical and bio-geochemical oceanic processes. Next the glidersâ capabilities are evaluated in the context of key applications. This includes an evaluation of 140 references presented in the peer-reviewed literature. It is found that GOOS has adequate coverage of sampling in the open ocean for several physical processes. There is a lack of data in the present GOOS in the transition regions between the open ocean and shelf seas. However, most of the documented scientific glider applications operate in this region, suggesting that a sustained glider component in the GOOS could fill that gap. Glider data are included for routine product generation (e.g. alerts, maps). Other noteworthy process-oriented applications where gliders are important survey tools include local sampling of the (sub)mesoscale, sampling in shallow coastal areas, measurements in hazardous environments, and operational monitoring. In most cases, the glider studies address investigations and monitoring of processes across multiple disciplines, making use of the ease to implement a wide range of sensors to gliders. The maturity of glider operations, the wide range of applications that map onto growing GOOS regional needs, and the maturity of glider data flow all justify the formal implementation of gliders into the GOOS. Remaining challenges include the execution of coordinated multinational missions in a sustained mode as well as considering capacity-building aspects in glider operations as well as glider data use
Hedgehog-mediated gut-taste neuron axis controls sweet perception in Drosophila
Dietary composition affects food preference in animals. High sugar intake suppresses sweet sensation from insects to humans, but the molecular basis of this suppression is largely unknown. Here, we reveal that sugar intake in Drosophila induces the gut to express and secrete Hedgehog (Hh) into the circulation. We show that the midgut secreted Hh localize to taste sensilla and suppresses sweet sensation, perception, and preference. We further find that the midgut Hh inhibits Hh signalling in the sweet taste neurons. Our electrophysiology studies demonstrate that the midgut Hh signal also suppresses bitter taste and some odour responses, affecting overall food perception and preference. We further show that the level of sugar intake during a critical window early in life, sets the adult gut Hh expression and sugar perception. Our results together reveal a bottom-up feedback mechanism involving a âgut-taste neuron axisâ that regulates food sensation and preference
Spatial structure of the 8200 cal yr BP event in northern Europe
International audienceA synthesis of well-dated high-resolution pollen records suggests a spatial structure in the 8200 cal yr BP event in northern Europe. The temperate, thermophilous tree taxa, especially Corylus, Ulmus, and Alnus, decline abruptly between 8300 and 8000 cal yr BP at most sites located south of 61° N, whereas there is no clear change in pollen values at the sites located in the North-European tree-line region. Pollen-based quantitative temperature reconstructions and several other, independent palaeoclimate proxies, such as lacustrine oxygen-isotope records, reflect the same pattern, with no detectable cooling in the sub-arctic region. The observed patterns challenges the general view of the wide-spread occurrence of the 8200 cal yr BP event in the North Atlantic region. An alternative explanation is that the cooling during the 8200 cal yr BP event took place mostly during the winter and spring, and the ecosystems in the south responded sensitively to the cooling during the onset of the growing season. In contrast, in the sub-arctic area, where the vegetation was still dormant and lakes ice-covered, the cold event is not reflected in pollen-based or lake-sediment-based records
Circulation patterns in the Gulf of Finland from daily to seasonal timescales
We studied circulation patterns in the Gulf of Finland (GoF), an estuary-like sub-basin of the Baltic Sea. Circulation patterns in the GoF are complex and vary from season to season and year to year. Estuarine circulation in the gulf is heavily modified by many factors, such as wind forcing, topography and geostrophic effects. Based on a 7-year run of the NEMO 3D hydrodynamic model with a 500âm horizontal resolution, we analysed seasonal changes of mean circulation patterns. We found that there were clear seasonal differences in the circulation patterns in the GoF. Features that moved or changed direction from season to season were damped or hidden in the averages. To further study these differences, we also carried out a self-organising map (SOM) analysis of currents for several latitudinal sections. The results of the SOM analysis emphasised the estuary-like nature of the GoF. Circulation changed rapidly from normal estuarine circulation to reverse estuarine circulation. The dominant southwesterly winds supported the reversal of the estuarine circulation. Both normal and reversed estuarine circulation were roughly as common in our data. The SOM analysis also demonstrated how the long-term cyclonic mean circulation field and the average salinity field emerged from the interaction of normal and reversed estuarine circulation
Level of Fatty Acid Binding Protein 5 (FABP5) Is Increased in Sputum of Allergic Asthmatics and Links to Airway Remodeling and Inflammation
FABP5 may contribute to the airway remodeling and inflammation in asthma by fine-tuning the levels of CysLTs, which induce VEGF production.</p
Ultraviolet B radiation modifies circadian time in epidermal skin and in subcutaneous adipose tissue
Background Recent findings suggest that circadian time regulates cellular functions in the skin and may affect protection against ultraviolet radiation (UVR). It is not known, however, whether UVR through skin directly affects the expression of circadian genes. We investigated the effect of ultraviolet B (UVB) exposure on cryptochrome circadian clock 1 (CRY1), cryptochrome circadian clock 2 (CRY2), and circadian associated repressor of transcription (CIART) genes. Methods Healthy volunteers (n = 12) were exposed to narrow-band UVB radiation of four standard erythemal dose (SED). Epidermal/dermal and subcutaneous adipose tissue samples were obtained by punch biopsies from irradiated and non-irradiated skin 10 cm away from the irradiated site 24 hours after UVB exposure. Gene expression of CRY1, CRY2, and CIART was measured using RT-PCR (TaqMan). Results Ultraviolet B radiation affected mRNA expression in the epidermal/dermal skin and in the subcutaneous adipose tissue. It down-regulated expression of CRY2 gene in the epidermal/dermal skin, whereas it up-regulated expression of CRY1 and CIART genes in the subcutaneous adipose tissue. Conclusion We showed for the first time that UVB radiation affects expression of circadian genes in the subcutaneous adipose tissue. Further studies are warranted to understand the mechanisms in detail.Peer reviewe
Paternal Diet Defines Offspring Chromatin State and Intergenerational Obesity
The global rise in obesity has revitalized a search for genetic and epigenetic factors underlying the disease. We present a Drosophila model of paternal-diet-induced intergenerational metabolic reprogramming (IGMR) and identify genes required for its encoding in offspring. Intriguingly, we find that as little as 2 days of dietary intervention in fathers elicits obesity in offspring. Paternal sugar acts as a physiological suppressor of variegation, desilencing chromatin-state-defined domains in both mature sperm and in offspring embryos. We identify requirements for H3K9/K27me3-dependent reprogramming of metabolic genes in two distinct germline and zygotic windows. Critically, we find evidence that a similar system may regulate obesity susceptibility and phenotype variation in mice and humans. The findings provide insight into the mechanisms underlying intergenerational metabolic reprogramming and carry profound implications for our understanding of phenotypic variation and evolution
Holocene changes in vegetation composition in northern Europe: why quantitative pollen-based vegetation reconstructions matter
International audienceWe present pollen-based reconstructions of the spatio-temporal dynamics of northern European regional vegetation abundance through the Holocene. We apply the Regional Estimates of VEgetation Abundance from Large Sites (REVEALS) model using fossil pollen records from eighteen sites within five modern biomes in the region. The eighteen sites are classified into four time-trajectory types on the basis of principal components analysis of both the REVEALS-based vegetation estimates (RVs) and the pollen percentage (PPs). The four trajectory types are more clearly separated for RVs than PPs. Further, the timing of major Holocene shifts, rates of compositional change, and diversity indices (turnover and evenness) differ between RVs and PPs. The differences are due to the reduction by REVEALS of biases in fossil pollen assemblages caused by different basin size, and inter-taxonomic differences in pollen productivity and dispersal properties. For example, in comparison to the PPs, the RVs show an earlier increase in Corylus and Ulmus in the early-Holocene and a more pronounced increase in grassland and deforested areas since the mid-Holocene. The results suggest that the influence of deforestation and agricultural activities on plant composition and abundance from Neolithic times was stronger than previously inferred from PPs. Relative to PPs, RVs show a more rapid compositional change, a largest decrease in turnover, and less variable evenness in most of northern Europe since 5200 cal yr BP. All these changes are primarily related to the strong impact of human activities on the vegetation. This study demonstrates that RV-based estimates of diversity indices, timing of shifts, and rates of change in reconstructed vegetation provide new insights into the timing and magnitude of major humandisturbance on Holocene regional vegetation, features that are critical in the assessment of humanimpact on vegetation, land-cover, biodiversity, and climate in the past
Prolonged sleep restriction induces changes in pathways involved in cholesterol metabolism and inflammatory responses
Sleep loss and insufficient sleep are risk factors for cardiometabolic diseases, but data on how insufficient sleep contributes to these diseases are scarce. These questions were addressed using two approaches: an experimental, partial sleep restriction study (14 cases and 7 control subjects) with objective verification of sleep amount, and two independent epidemiological cohorts (altogether 2739 individuals) with questions of sleep insufficiency. In both approaches, blood transcriptome and serum metabolome were analysed. Sleep loss decreased the expression of genes encoding cholesterol transporters and increased expression in pathways involved in inflammatory responses in both paradigms. Metabolomic analyses revealed lower circulating large HDL in the population cohorts among subjects reporting insufficient sleep, while circulating LDL decreased in the experimental sleep restriction study. These findings suggest that prolonged sleep deprivation modifies inflammatory and cholesterol pathways at the level of gene expression and serum lipoproteins, inducing changes toward potentially higher risk for cardiometabolic diseases
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