The Effects of the Laurentide Ice Sheet on North American Climate during the Last Glacial Maximum

A climate model, consisting of an atmospheric general circulation model coupled with a simple model of the oceanic mixed layer, is used to investigate the effects of the continental ice distribution of the last glacial maximum (LGM) on North American climate. This model has previously been used to simulate the LGM climate, producing temperature changes reasonably in agreement with paleoclimatic data. The LGM distribution of continental ice according to the maximum reconstruction of HUGHES et al. (1981) is used as input to the model. In response to the incorporation of the expanded continental ice of the LGM, the model produces major changes in the climate of North America. The ice sheet exerts an orographic effect on the tropospheric flow, resulting in a splitting of the midlatitude westerlies in all seasons but summer. Winter temperatures are greatly reduced over a wide region south of the Laurentide ice sheet, although summer cooling is less extensive. An area of reduced soil moisture develops in the interior of North America just south of the ice margin. At the same time, precipitation increases in a belt extending from the extreme southeastern portion of the ice sheet eastward into the North Atlantic. Some of these findings are similar to paleoclimatic inferences based on geological evidence.Un modèle climatique, composé d'un modèle de circulation atmosphérique général associé à un modèle simple de la couche océanique mixte, a servi à étudier l'influence de la répartition des glaciers continentaux sur le climat de l'Amérique du Nord au dernier pléniglaciaire. Ce modèle avait déjà servi pour simuler le climat au dernier pléniglaciaire; il a montré des changements de températures concordant assez bien avec les données paléoclimatiques. La répartition des glaces continentales pendant le pléniglaciaire selon l'hypothèse d'extension maximale de HUGHES et al. (1981) a servi à la modélisation. En réponse à l'incorporation des données de cette hypothèse, le modèle fait voir des changements majeurs dans le climat de l'Amérique du Nord. La présence de la calotte glaciaire fait ressortir l'influence de l'orographie sur le flux troposphérique qui se concrétise par une séparation des vents d'ouest aux latitudes moyennes durant toutes les saisons, sauf l'été. Les températures hivernales s'abaissent substantiellement dans une vaste région située au sud de la calotte laurentidienne, bien que le refroidissement soit moindre durant l'été. Une zone sèche se développe immédiatement au sud de la marge glaciaire. Au même moment, les précipitations augmentent dans la région qui s'étend de l'extrémité sud-est de la calotte glaciaire jusque dans l'Atlantique Nord, à l'est. Certains de ces résultats sur la nature du paléoclimat sont similaires aux déductions que les données géologiques ont inspirées.Um die Auswirkungen der kontinentalen Eisverbreitung im jüngsten glazialen Maximum auf das nordamerikanische Klima zu erforschen, wird ein Klima-Modell benutzt. das aus einem Modell der Hauptluftströmung in Verbindung mit einem einfachen Modell der gemischten ozeanischen Schicht besteht. Frùher wurde dieses Modell benutzt, um das Klima im jüngsten glazialen Maximum zu simulieren. Die Ergebnisse haben Temperaturschwankungen ergeben, die einigermapen genau mit den paleoklimatischen Daten übereinstimmten. Ausgegangen wurde bei dem Modell von der Verteilung des kontinentalen Eises im jüngsten glazialen Maximum entsprechend der Maximum-Rekonstruktion von HUGHES et al. (1981). AIs Antwort auf die Einverleibung des ausgedehnten kontinentalen Eises im jüngsten glazialen Maximum produziert das Modell bedeutende Veränderungen im nordamerikanischen Klima. Die Eisdecke übt eine orographische Wirkung auf die troposphärische Luftströmung aus, was zu einer Aufsplitterung der westlichen Winde mittlerer Breite in alien Jahreszeiten auBer im Sommer führt. Die Winter-Temperaturen sinken stark in einem weiten Gebiet südlich der laurentischen Eisdecke, während die sommerliche Abkühlung weniger stark ausfällt. Im Innern Nordamerikas südlich der Eisgrenze entwickelt sich ein Gebiet verringerter Bodenfeuchtigkeit. Gleichzeitig nehmen die Niederschläge innerhalb eines Gürtels zu, der von dem äupersten südöstlichen Teil der Eisdecke ostwärts in den Nordatlantik reicht. Einige dieser Ergebnisse decken sich mit paleoklimatischen Folgerungen, die sich auf geologische Nachweise stützen

The Third Way to Interacting p-form Theories

We construct a class of interacting $(d-2)$-form theories in $d$ dimensions that are `third way' consistent. This refers to the fact that the interaction terms in the $p$-form field equations of motion neither come from the variation of an action nor are they off-shell conserved on their own. Nevertheless the full equation is still on-shell consistent. Various generalizations, e.g. coupling them to $(d-3)$-forms, where 3-algebras play a prominent role, are also discussed. The method to construct these models also easily recovers the modified 3$d$ Yang-Mills theory obtained earlier and straightforwardly allows for higher derivative extensions

Physiological responses of garden cress (L. sativum) to different types of microplastics

In this study, for the first time, acute and chronic toxicity caused by four different kinds of microplastics: polypropylene (PP), polyethylene (PE), polyvinylchloride (PVC), and a commercial mixture (PE + PVC) on Lepidium sativum were evaluated. Parameters considered were: i) biometric parameters (e.g. percentage inhibition of seed germination, plant height, leaf number and fresh biomass productions); and ii) oxidative stress (e.g. levels of hydrogen peroxide, glutathione, and ascorbic acid). On plants exposed to chronic stress chlorophylls, carotenoids, aminolaevulinic acid, and proline productions were, also, evaluated. PVC resulted the most toxic than other plastic materials tested. This study represents the first paper highlighting microplastics are able to produce oxidative burst in tested plants and could represent an important starting point for future researches on biochemical effects of microplastic in terrestrial environments such as agroecosystems

The economic value of a climate service for water irrigation. A case study for Castiglione District, Emilia-Romagna, Italy

The use of climate services to support decision makers in incorporating climate change adaptation in their practices is well established and widely recognized. Their role is particularly relevant in a climate sensitive sector like agriculture where they can provide evidence for the adoption of transformative solutions from seasonal to multi-decadal time scales. Adaptation solutions are often expensive and irreversible in the short/medium run. Accordingly, end users should have a reliable reference to make decisions. Here, we propose and apply a methodology, co-developed with service developers and a representative potential user, to assess the value of the IRRICLIME climate service, whose information is used to support decisions on climate smart irrigation investment by water planners in a sub-irrigation district in Italy. We quantify the value of the information provided by the climate service, that we consider the intrinsic value of the service, or the value of adaptation. We demonstrate that under three different climate change scenarios, the maximum potential value of IRRICLIME could range between 2,985 €/ha and 7,480 €/ha

IL MODELLO DI REGRESSIONE QUANTILE NELL’ANALISI DELLE DETERMINANTI DELLA QUALITA’ DELLA VITA IN UNA POPOLAZIONE ANZIANA

Obiettivi. L\u2019obiettivo di questo studio \ue8 spiegare l\u2019associazione tra alcune importanti covariate e la qualit\ue0 della vita percepita (HRQoL) in soggetti anziani. Metodi. I dati sono stati raccolti nell\u2019ambito di uno studio longitudinale che coinvolge 5256 soggetti ultrasesantacinquenni. La scala-termometro del questionario EQ-5D, la EQ-VAS, \ue8 stata utilizzata per ottenere una misura sintetica di qualit\ue0 della vita. L\u2019EQ-VAS Score \ue8 stato modellato utilizzando la regressione quantile. Questo approccio metodologico \ue8 stato preferito alla regressione lineare a causa della particolare distribuzione del punteggio EQ-VAS. Le principali covariate inserite nel modello sono: quantit\ue0 settimanale di attivit\ue0 fisica, capaocit\ue0 di svolgimento delle attivit\ue0 quotidiane ( questionari ADL e IADL ), presenza di patologie cardiovascolari, diabete, ipertensione e colesterolo, dolori articolare e informazioni socio-demografiche. Principali Risultati. 1) Anche valori bassi di attivit\ue0 fisica sono associati significativamente ed in modo positivo alla qualit\ue0 della vita percepita. 2) Problemi nella attivit\ue0 quotidiane, almeno un evento cardiovascolare e dolori articolari contribuiscono fortemente a ridurre il punteggio EQ-VAS

Ecotoxicity of basil (Ocimum Basilicum) extract in aquaculture feeds: Is it really eco-safe for the aquatic environment?

Plant extract and essential oils are gaining application in aquaculture, but data about their environmental impact are limited and their potential effects on aquatic organisms are largely unknown. For this study, ecotoxicity tests were performed under standardized conditions on fish feed supplemented with 3 % w/w of a basil supercritical extract (F1-BEO; substance A), F1-BEO extract (substance B), and fish feed without F1-BEO extract (substance C) on three model species of different trophic levels (bacteria, primary producer, primary consumer) considered representative for freshwater (Aliivibrio fischeri, Raphidocelis subcapitata, Daphnia magna) and marine (A. fischeri, Phaeodactylum tricornutum, Paracentrotus lividus) ecosystems. Ecotoxicological response was largely comparable within the same trophic level (whichever the ecosystem). EC50 was not calculable in the concentration range here tested (3.9–500 mg/L) for freshwater and marine microalgae, suggesting that none of the substances were toxic for primary producers. Reduction of A. fischeri bioluminescence at the tested concentration (0.5–10 mg/L) was observed only for substance A (EC50 9.53 mg/L and 9 mg/L for freshwater and marine ecosystems, respectively). Notably, in P. lividus embryotoxicity was higher for substances A (EC50 1.80 mg/L) and C (EC50 4.6 mg/L) than for substance B (EC50 7.10 mg/L), suggesting a toxic effect due to feed dissolution. In contrast, substance B was more toxic (EC50 0.34 mg/L) in D. magna than substances A (EC50 3.98 mg/L) and C (EC50 5.50 mg/L). Based on the Globally Harmonized System of Classification and Labelling of Chemicals, all substances were categorized Acute 2, except for substance A which was categorized Acute 1 for D. magna. Overall, the substances were found to be potentially toxic for an aquatic ecosystem, especially for primary consumer. Further study of plant extract and essential oils is needed to better understand their effects and fate on the aquatic environment

Arx acts as a regional key selector gene in the ventral telencephalon mainly through its transcriptional repression activity

AbstractThe homeobox-containing gene Arx is expressed during ventral telencephalon development and required for correct GABAergic interneuron tangential migration from the ganglionic eminences to the olfactory bulbs, cerebral cortex and striatum. Its human ortholog is associated with a variety of neurological clinical manifestations whose symptoms are compatible with the loss of cortical interneurons and altered basal ganglia-related activities. Herein, we report the identification of a number of genes whose expression is consistently altered in Arx mutant ganglionic eminences. Our analyses revealed a striking ectopic expression in the ganglionic eminences of several of these genes normally at most marginally expressed in the ventral telencephalon. Among them, Ebf3 was functionally analyzed. Thus, its ectopic expression in ventral telencephalon was found to prevent neuronal tangential migration. Further, we showed that Arx is sufficient to repress Ebf3 endogenous expression and that its silencing in Arx mutant tissues partially rescues tangential cell movement. Together, these data provide new insights into the molecular pathways regulated by Arx during telencephalon development

Role of PET/CT in the detection of liver metastases from colorectal cancer

The aim of this study was to compare the diagnostic accuracy of 2-[fluorine-18] fluoro-2-deoxy-D-glucose positron emission tomography (F-18-FDG-PET) and computed tomography (CT) with PET/CT in the detection of liver metastases during tumour staging in patients suffering from colorectal carcinoma for the purposes of correct surgical planning and follow-up. A total of 467 patients underwent a PET/CT scan using an iodinated contrast medium. We compared images obtained by the single PET scan, the single CT scan and by the fusion of the two procedures (PET/CT). The final diagnosis was obtained by histological examination and/or by the follow-up of all patients, including those who did not undergo surgery or biopsy. The PET scan had 94.05% sensitivity, 91.60% specificity and 93.36% accuracy; the CT scan had 91.07% sensitivity, 95.42% specificity and 92.29% accuracy. The combined procedures (PET/CT) had the following values: sensitivity 97.92%, specificity 97.71% and accuracy 97.86%. This study indicates that PET/CT is very useful in staging and restaging patients suffering from colorectal cancer. It was particularly useful when recurrences could not be visualised either clinically or by imaging despite increasing tumour markers, as it guaranteed an earlier diagnosis. PET/CT not only provides high diagnostic performance in terms of sensitivity and specificity, enabling modification of patient treatment, but it is also a unique, high-profile procedure that can produce cost savings

The atmospheric response to a thermohaline circulation collapse: scaling relations for the Hadley circulation and the response in a coupled climate model

The response of the tropical atmosphere to a collapse of the thermohaline circulation (THC) is investigated by comparing two 5-member ensemble runs with a coupled climate model (CCM), the difference being that in one ensemble a hosing experiment was performed. An extension of the Held–Hou–Lindzen model for the Hadley circulation is developed to interpret the results. The forcing associated with a THC collapse is qualitatively similar to, but smaller in amplitude than, the solstitial shift from boreal summer to winter. This forcing results from reduced ocean heat transport creating an anomalous cross-equatorial SST gradient. The small amplitude of the forcing makes it possible to arrive at analytical expressions using standard perturbation theory. The theory predicts the latitudinal shift between the Northern Hemisphere (NH) and Southern Hemisphere (SH) Hadley cells, and the relative strength of the anomalous cross-equatorial Hadley cell compared to the solstitial cell. The poleward extent of the Hadley cells is controlled by other physics. In the NH the Hadley cell contracts, while zonal velocities increase and the subtropical jet shifts equatorward, whereas in the SH cell the opposite occurs. This behavior can be explained by assuming that the poleward extent of the Hadley cell is determined by baroclinic instability: it scales with the inverse of the isentropic slopes. Both theory and CCM results indicate that a THC collapse and changes in tropical circulation do not act in competition, as a possible explanation for abrupt climate change; they act in concert.<br/

Smart Climate Hydropower Tool: A Machine-Learning Seasonal Forecasting Climate Service to Support Cost–Benefit Analysis of Reservoir Management

This study proposes a climate service named Smart Climate Hydropower Tool (SCHT) and designed as a hybrid forecast system for supporting decision-making in a context of hydropower production. SCHT is technically designed to make use of information from state-of-art seasonal forecasts provided by the Copernicus Climate Data Store (CDS) combined with a range of different machine learning algorithms to perform the seasonal forecast of the accumulated inflow discharges to the reservoir of hydropower plants. The machine learning algorithms considered include support vector regression, Gaussian processes, long short-term memory, non-linear autoregressive neural networks with exogenous inputs, and a deep-learning neural networks model. Each machine learning model is trained over past decades datasets of recorded data, and forecast performances are validated and evaluated using separate test sets with reference to the historical average of discharge values and simpler multiparametric regressions. Final results are presented to the users through a user-friendly web interface developed from a tied connection with end-users in an effective co-design process. Methods are tested for forecasting the accumulated seasonal river discharges up to six months in advance for two catchments in Colombia, South America. Results indicate that the machine learning algorithms that make use of a complex and/or recurrent architecture can better simulate the temporal dynamic behaviour of the accumulated river discharge inflow to both case study reservoirs, thus rendering SCHT a useful tool in providing information for water resource managers in better planning the allocation of water resources for different users and for hydropower plant managers when negotiating power purchase contracts in competitive energy markets