290 research outputs found
A shared frequency set between the historical mid-latitude aurora records and the global surface temperature
Herein we show that the historical records of mid-latitude auroras from 1700
to 1966 present oscillations with periods of about 9, 10-11, 20-21, 30 and 60
years. The same frequencies are found in proxy and instrumental global surface
temperature records since 1650 and 1850, respectively and in several planetary
and solar records. Thus, the aurora records reveal a physical link between
climate change and astronomical oscillations. Likely, there exists a modulation
of the cosmic ray flux reaching the Earth and/or of the electric properties of
the ionosphere. The latter, in turn, have the potentiality of modulating the
global cloud cover that ultimately drives the climate oscillations through
albedo oscillations. In particular, a quasi 60-year large cycle is quite
evident since 1650 in all climate and astronomical records herein studied,
which also include an historical record of meteorite fall in China from 619 to
1943. These findings support the thesis that climate oscillations have an
astronomical origin. We show that a harmonic constituent model based on the
major astronomical frequencies revealed in the aurora records is able to
forecast with a reasonable accuracy the decadal and multidecadal temperature
oscillations from 1950 to 2010 using the temperature data before 1950, and vice
versa. The existence of a natural 60-year modulation of the global surface
temperature induced by astronomical mechanisms, by alone, would imply that at
least 60-70% of the warming observed since 1970 has been naturally induced.
Moreover, the climate may stay approximately stable during the next decades
because the 60-year cycle has entered in its cooling phase.Comment: 18 pages, 11 figure
Multivariate approach for the retrieval of phytoplankton size structure from measured light absorption spectra in the Mediterranean Sea (BOUSSOLE site)
Models based on the multivariate partial least squares (PLS) regression technique are developed for the retrieval of phytoplankton size structure from measured light absorption spectra (BOUSSOLE site, northwestern Mediterranean Sea). PLS-models trained with data from the Mediterranean Sea showed good accuracy in retrieving, over the nine-year BOUSSOLE time series, the concentrations of total chlorophyll a [Tchl a], of the sum of seven diagnostic pigments and of pigments associated with micro, nano, and picophytoplankton size classes separately. PLS-models trained using either total particle orphytoplankton absorption spectra performed similarly, and both reproduced seasonal variations of biomass and size classes derived by high performance liquid chromatography. Satisfactory retrievals were also obtained using PLS-models trained with a data set including various locations of the world’s oceans, with however a lower accuracy. These results open the way to an application of this method to absorption spectra derived from hyperspectral and field satellite radiance measurements
The Reliability of Global and Hemispheric Surface Temperature Records
The purpose of this review article is to discuss the development and associated estimation of uncertainties in the global and hemispheric surface temperature records. The review begins by detailing the groups that produce surface temperature datasets. After discussing the reasons for similarities and differences between the various products, the main issues that must be addressed when deriving accurate estimates, particularly for hemispheric and global averages, are then considered. These issues are discussed in the order of their importance for temperature records at these spatial scales: biases in SST data, particularly before the 1940s; the exposure of land-based thermometers before the development of louvred screens in the late 19th century; and urbanization effects in some regions in recent decades. The homogeneity of land-based records is also discussed; however, at these large scales it is relatively unimportant. The article concludes by illustrating hemispheric and global temperature records from the four groups that produce series in near-real time
A Notch updated
Cell–cell signaling mediated by the Notch receptor is iteratively involved in numerous developmental contexts, and its dysregulation has been associated with inherited genetic disorders and cancers. The core components of the signaling pathway have been identified for some time, but the study of the modulation of the pathway in different cellular contexts has revealed many layers of regulation. These include complex sugar modifications in the extracellular domain as well as transit of Notch through defined cellular compartments, including specific endosomes
Effects of structural environmental enrichment on welfare of juvenile seabream (Sparus aurata)
Current production systems of finfish aquaculture, and in particular intensive farming systems, can cause welfare problems leading not only to poor condition of the fish but also to a decrease in product quality. Adding structural environmental enrichment (EE) to bare rearing environments may improve the welfare of certain cultured fish. In this study we experimentally demonstrate the positive effects of adding structural EE on rearing environments of juvenile seabream (Sparus aurata). Fish maintained for 35 days with EE showed less aggression and interactions with the net pen, and lower erosion of pectoral and caudal fins, compared to fish kept in bare conditions (non-enriched, NE). In addition, EE modified the horizontal distribution of fish in the experimental cage, increasing the use of the inner areas. Non-significant effects of EE were observed on fish body condition and growth, and on brain monoamines levels and mortality. Nevertheless, this work highlights the potential use of structural EE to improve welfare of juvenile seabream, which might be feasible to apply at larger-commercial scale.Agência financiadora
Aquicultura Balear S.A.U (Grupo Culmarex)
Portuguese Foundation for Science and Technology
UID/Multi/04326/2019
Spanish national funds from MINECO (R+D project: PHENOFISH)
CTM2015- 69126-C2-1-Rinfo:eu-repo/semantics/publishedVersio
Enhanced deformation of limestone and sandstone in the presence of high pCO2 fluids
International audienceGeological repositories subject to the injection of large amounts of anthropogenic carbon dioxide will undergo chemical and mechanical instabilities for which there are currently little experimental data. This study reports on experiments where low and high pCO2 (8~MPa) aqueous fluids where injected into natural rock samples. The experiments were performed in flow-through triaxial cells, where the vertical and confining stresses, temperature, and pressure and composition of the fluid were separately controlled and monitored. The axial vertical strains of two limestones and one sandstone were continuously measured during separate experiments for several months, with a strain rate resolution of 10^-11 s-1. Fluids exiting the triaxial cells where continuously collected and their compositions analysed. The high pCO2 fluids induced an increase in strain rates of the limestones by up to a factor of 5, compared to the low pCO2 fluids. Injection of high pCO2 fluids into the sandstone resulted in deformation rates one order of magnitude smaller than the limestones. The creep accelerating effect of high pCO2 fluids with respect to the limestones was mainly due to the acidification of the injected fluids, resulting in a significant increase in solubility and reaction kinetics of calcite. Compared to the limestones, the much weaker response of the sandstone was due to the much lower solubility and reactivity of quartz in high pCO2 fluids. In general, all samples showed a positive correlation between fluid flow rate and strain rate. X-ray tomography results revealed significant increases in porosity at the inlet portion of each core; the porosity increases were dependent on the original lithological structure and composition. The overall deformation of the samples is interpreted in terms of simultaneous dissolution reactions in pore spaces and intergranular pressure solution creep
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An exploration of patient-reported symptoms in systemic lupus erythematosus and the relationship to health-related quality of life
Objective: The aim of this study was to explore the most distressing symptoms of systemic lupus erythematosus (SLE) and determine how these relate to health-related quality of life (HRQoL), anxiety/depression, patient demographics and disease characteristics (duration, activity, organ damage).
Methods: In a cross-sectional study, patients with SLE (n=324, age 18-84 years) gave written responses regarding which SLE-related symptoms they experienced as most difficult. Their responses were categorized. Within each category, patients reporting a specific symptom were compared with non-reporters and analyzed for patient demographics, disease duration, results from the questionnaires: Medical Outcomes Study Short-Form 36, Hospital Anxiety and Depression Scale, Systemic Lupus Activity Measure, SLE disease activity index and the Systemic Lupus International Collaboration Clinics/American College of Rheumatology damage index.
Results: 23 symptom categories were identified. Fatigue (51%), Pain (50%) and Musculoskeletal distress (46%) were most frequently reported. Compared with non-reporters, only patients reporting Fatigue showed statistically significant impact on both mental and physical components of HRQoL.. Patients with no present symptoms (10%) had higher HRQoL (p<0.001) and lower levels of depression (p<0.001), anxiety (p<0.01) and disease activity (SLAM) (p<0.001).
Conclusion: Fatigue, pain or musculoskeletal distress dominated the reported symptoms in approximately half of the patients. Only patients reporting Fatigue scored lower on both mental and physical aspects of HRQoL. Our results emphasize the need for further support and interventions to ease the symptom load and improve HRQoL in patients with SLE. Our findings further indicate that this need is particularly urgent for patients with symptoms of pain or fatigue
α7-Nicotinic Acetylcholine Receptor: Role in Early Odor Learning Preference in Mice
Recently, we have shown that mice with decreased expression of α7-nicotinic acetylcholine receptors (α7) in the olfactory bulb were associated with a deficit in odor discrimination compared to wild-type mice. However, it is unknown if mice with decreased α7-receptor expression also show a deficit in early odor learning preference (ELP), an enhanced behavioral response to odors with attractive value observed in rats. In this study, we modified ELP methods performed in rats and implemented similar conditions in mice. From post-natal days 5–18, wild-type mice were stroked simultaneously with an odor presentation (conditioned odor) for 90 s daily. Control mice were only stroked, exposed to odor, or neither. On the day of testing (P21), mice that were stroked in concert with a conditioned odor significantly investigated the conditioned odor compared to a novel odor, as observed similarly in rats. However, mice with a decrease in α7-receptor expression that were stroked during a conditioned odor did not show a behavioral response to that odorant. These results suggest that decreased α7-receptor expression has a role in associative learning, olfactory preference, and/or sensory processing deficits
AIP4/Itch Regulates Notch Receptor Degradation in the Absence of Ligand
International audienceBACKGROUND:The regulation of Notch signaling heavily relies on ubiquitination events. Drosophila Su(dx), a member of the HECT family of ubiquitin-ligases, has been described as a negative regulator of Notch signaling, acting on the post-endocytic sorting of Notch. The mammalian ortholog of Su(dx), Itch/AIP4, has been shown to have multiple substrates, including Notch, but the precise events regulated by Itch/AIP4 in the Notch pathway have not been identified yet.METHODOLOGY/PRINCIPAL FINDINGS:Using Itch-/- fibroblasts expressing the Notch1 receptor, we show that Itch is not necessary for Notch activation, but rather for controlling the degradation of Notch in the absence of ligand. Itch is indeed required after the early steps of Notch endocytosis to target it to the lysosomes where it is degraded. Furthermore Itch/AIP4 catalyzes Notch polyubiquitination through unusual K29-linked chains. We also demonstrate that although Notch is associated with Itch/AIP4 in cells, their interaction is not detectable in vitro and thus requires either a post-translational modification, or a bridging factor that remains to be identified.CONCLUSIONS/SIGNIFICANCE:Taken together our results identify a specific step of Notch regulation in the absence of any activation and underline differences between mammalian and Drosophila Notch pathways
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