671 research outputs found
Linkages between rapid climate variability and deepâsea benthic foraminifera in the deep Subantarctic South Atlantic during the last 95âkyr
We present a high-resolution record of benthic foraminifera fauna from a sediment core retrieved from the South Cape Basin (Subantarctic South Atlantic) spanning the last glacial cycle (95 kyr). Information provided by benthic foraminiferal assemblages together with paleoclimate proxies from the same core allow us to interpret changes in the style of primary production (episodic vs sustained) in relation to abrupt climate oscillations. Our results indicate that fluctuations in the abundance of the phytodetritus- related species, Epistominella exigua, are concomitant with millennial scale high latitude climate perturbations. Episodic phytoplankton blooms increased during a negative mode of the bipolar seesaw, irrespective of the magnitude of the perturbation (i.e., HS versus non-H stadial events). We provide a hypothesis linking the frequency and intensity of these events to atmospheric perturbations, interhemispheric climate variability and millennial scale changes in atmospheric CO2. A notable exception to the overall pattern is the generally high abundance of E. exigua across the globally synchronous onset of glacial MIS 4, a period generally characterized by increased dustiness and low quality organic carbon as inferred by the percentage of the non-phytodetritus species. This highlights the special characteristics governing the onset of MIS 4 in the Subantarctic
SEOM-GECP-GETTHI Clinical Guidelines for the treatment of patients with thymic epithelial tumours (2021)
Chemotherapy; Lenvatinib; Thymic epithelial tumoursQuimioterapia; lenvatinib; Tumores epiteliales tĂmicosQuimioterĂ pia; Lenvatinib; Tumors epitelials tĂmicsThymic epithelial tumours (TET) represent a heterogeneous group of rare malignancies that include thymomas and thymic carcinoma. Treatment of TET is based on the resectability of the tumour. If this is considered achievable upfront, surgical resection is the cornerstone of treatment. Platinum-based chemotherapy is the standard regimen for advanced TET. Due to the rarity of this disease, treatment decisions should be discussed in specific multidisciplinary tumour boards, and there are few prospective clinical studies with new strategies. However, several pathways involved in TET have been explored as potential targets for new therapies in previously treated patients, such as multi-tyrosine kinase inhibitors with antiangiogenic properties and immune checkpoint inhibitors (ICI). One third of patient with thymoma present an autoimmune disorders, increasing the risk of immune-related adverse events and autoimmune flares under ICIs. In these guidelines, we summarize the current evidence for the therapeutic approach in patients with TET and define levels of evidence for these decisions
Life on the ice-edge: Paleoenvironmental significance of the radiolarian species Amphimelissa setosa in the northern hemisphere
The high-latitude Northern Hemisphere is a key region in the global climate balance. Variations in sea-ice extent affect biological productivity, CO2 exchange and carbon drawdown. Marine proxies indicative of proximity of the ice-marginal zone are therefore essential to understand these processes. Amphimelissa setosa is nowadays a dominant radiolarian species in the Arctic basin and very abundant in the high-latitude North Atlantic. This species, now absent from the North Pacific, has been widely used as a qualitative proxy of modern and past environmental conditions in the high-latitude Northern Hemisphere. Using our new and published data on the distribution of A. setosa in plankton, sediment trap, surface sediment and downcore samples, we provide a quantitative ecological context for the occurrence of this species. We find that the optimal depth and season of A. setosa in the modern North Atlantic and the Chukchi Sea are 160 m and the late boreal summer/early fall (AugustâOctober), respectively. A regression model combining environmental variables (temperature, salinity, silicate and chlorophyll-a concentrations, apparent oxygen utilization, sea-ice) at that season and depth, are able to explain 43% of the distribution of this species in surface sediments. Based on these new findings, we conclude that the presence of A. setosa in surface sediments is closely related to high primary production in the proximity of the sea-ice and areas of ice rafting. The onset of this species started at ca. 1.5 Ma in the North Pacific, linked to a gradual cooling, increased silica availability and southward advance of the ice-margins since the Early Pleistocene. Amphimelissa setosaâs decline in this region was likely caused by the development of a quasi-permanent halocline, perennial sea-ice and depletion of silica during marine isotope stage 4. In the high-latitude North Atlantic, the relative abundance of A. setosa appears to be related to cooling and supply of dissolved silica from the continent during ice-rafting events. The comprehensive approach taken in this study suggest that A. setosa is a useful proxy to explore past variations in the ice-cover in the high-latitude Northern Hemisphere.Shirshov Institute of Oceanology | Ref. 0149-2019-000
Simulation and experimental validation of a helical coil used as condenser in a heat pump for domestic water heating in a tank
Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.Although the use of helical coils are widely used in
engineering applications for heating and cooling production
there is little information available about their thermal
behavior. The purpose of this work was to simulate the
behavior of a helical coil used as condenser in a heat pump for
domestic hot water heating in a tank. The simulation was
carried out by developing a mathematical model. The
mathematical model was implemented in a computer program.
The program results were validated against the experimental
results obtained by using an experimental set-up. In the paper
the mathematical model is detailed, the experimental setup and
the experimental procedure are described and the results are
presented and discussed.dc201
How blebs and pseudopods cooperate during chemotaxis
Two motors can drive extension of the leading edge of motile cells: actin polymerization and myosin-driven contraction of the cortex, producing fluid pressure and the formation of blebs. Dictyostelium cells can move with both blebs and actin-driven pseudopods at the same time, and blebs, like pseudopods, can be orientated by chemotactic gradients. Here we ask how bleb sites are selected and how the two forms of projection cooperate. We show that membrane curvature is an important, yet overlooked, factor. Dictyostelium cells were observed moving under agarose, which efficiently induces blebbing, and the dynamics of membrane deformations were analyzed. Blebs preferentially originate from negatively curved regions, generated on the flanks of either extending pseudopods or blebs themselves. This is true of cells at different developmental stages, chemotaxing to either folate or cyclic AMP and moving with both blebs and pseudopods or with blebs only. A physical model of blebbing suggests that detachment of the cell membrane is facilitated in concave areas of the cell, where membrane tension produces an outward directed force, as opposed to pulling inward in convex regions. Our findings assign a role to membrane tension in spatially coupling blebs and pseudopods, thus contributing to clustering protrusions to the cell front
Homegreens - Aquaponics System as an Educational Tool towards a Sustainable Future
Aquaponics is an integrated production practice that emerges from the combi-nation of two farming techniques: hydroponics and aquaculture. It consists in a simulation of a natural ecosystem that grows plants without soil substrate in the nutrient enriched waters recirculated from aquaculture systems. This type of production offers several advantages, namely economic and ecological ones. Homegreens is a project that aims to create small saltwater and freshwater aquaponic sys-tems, which can be installed in schools and serve as a didactic tool for introducing contents such as biology and sustainability to a juvenile audience. Implemented by a designers, biol-ogists and agronomistsâ multidisciplinary team, the methodology was based on the develop-ment and quantitative validation of prototypes, and the installation and qualitative analyses of userâs interaction. These small scale aquaponic systems consists on a grow bed, an aquarium with a capacity for 45L, a protection barrier for the plantâs roots, aeration, biofilters and a thermostat. Sever-al simplified models were developed, presented and installed in two primary schools. Labor-atory tests were conducted to validate the use of a cork grow bed and a 3D printed polya-cid lactic (PLA) aeration and biofilter system. Childrenâs engagement and interaction with these simplified models, indicates that these systems will provide a biology and sustainability related group learning opportunity.info:eu-repo/semantics/publishedVersio
Alectinib after failure to crizotinib in patients with ALK-positive non-small cell lung cancer : results from the Spanish early access program
Altres ajuts: Roche Farma, S.A.This retrospective observational study analyzed the clinical characteristics, treatment patterns and outcomes of 120 patients with advanced ALK-positive nonsmall-cell lung cancer (ALK+ NSCLC) according to data collected between November 2019 and October 2020 in 38 Spanish hospitals. Patients had progressed after 1-5 prior treatment lines (which included crizotinib in any prior line) and received subsequent therapy with alectinib in a local expanded access program. Median age was 58.7 years, 50% of patients were female, 64.1% had ECOG PS of 0-1, 85% presented stage IV, 95% had adenocarcinoma histology and 20.8% had brain metastases. After a median 9.6 months of alectinib treatment, objective response rate (ORR) was 54.5%, disease control rate (DCR) was 80%, median progression-free survival (PFS) was 9.4 months and median overall survival (OS) was 24.1 months. Patients with brain metastases achieved an intracranial DCR of 71.4%. Adverse events (AEs) were reported in 35.8% of patients (14.2% of AEs were grade â„3). Over 40% of patients received some treatment after alectinib, most frequently lorlatinib (65.2%) and brigatinib (32.6%). This study provides information on real-world treatment patterns and confirms the tolerability and prolonged PFS and OS observed with alectinib in clinical trials, in unselected pretreated patients with advanced ALK+ NSCLC
Ocean and atmosphere teleconnections modulate east tropical Pacific productivity at late to middle Pleistocene terminations
The modern Eastern Equatorial Pacific (EEP) is a key oceanographic region for regulating the Earth's climate system, accounting for between 5â10% of global marine production whilst also representing a major source of carbon dioxide efflux to the atmosphere. Changes in ocean dynamics linked to the nutrient supply from the Southern Ocean have been suggested to have played a dominant role in regulating EEP productivity over glacialâinterglacial timescales of the past 500 ka. Yet, the full extent of the climate and oceanic teleconnections and the mechanisms promoting the observed increase of productivity occurring at glacial terminations remain poorly understood. Here we present multi-proxy, micropaleontological, geochemical and sedimentological records from the easternmost EEP to infer changes in atmospheric patterns and oceanic processes potentially influencing regional primary productivity over glacialâinterglacial cycles of the mid-late Pleistocene (âŒ0â650 ka). These proxy data support a leading role for the northâsouth migration of the Intertropical Convergence Zone (ITCZ) in shaping past productivity variability in the EEP. Productivity increases during glacial periods and notably peaks at major and âextraâ glacial terminations (those occurring 1â2 precession cycles after some major terminations) coincident with the inferred southernmost position of the ITCZ. The comparison of our reconstructions with proxy records of climate variability suggests the intensification of related extratropical atmospheric and oceanic teleconnections during deglaciation events. These processes may have re-activated the supply of southern sourced nutrients to the EEP, potentially contributing to enhanced productivity in the EEP and thus counterbalancing the oceanic carbon dioxide outgassing at glacial terminations
Prosumer and Product Design Through Digital Tools
Currently, the growing interest of users and consumers in the participation of the creative process has led to the typical âmaker cultureâ practices. Consequently, there is an increasing number of prosumers - users who produce what they consume - who want to be part of the design and transformation process of the products. In order to achieve it, prosumers have begun to use digital tools that greatly facilitate this task. These tools could vary depending on the number of users involved in the process and the freedom of participation that they have on the product. It has been presented a number of qualitative classification of cases involving the end user, individually or collectively, that has influenced as a prosumer in the product design process. The objective is to study the use of digital tools in the creative phase within the design process according to their different levels of participation with respect to the final product. The cases are shown in four tables according to the number of users involved in the process and their level of participation. In these tables, other important aspects related to the study of digital tools such as the type of contribution of the prosumer to the product or the design phase in which he participates will be identified. In conclusion, this work will show if there is a pattern in the use of digital tools according to the number of users involved in the process and the freedom of participation that they have and which are the reasons for their use
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