Short-term effects of game on visual-spatial attention: an empirical research on preschool children

openIl presente elaborato riguarda lo studio condotto presso il laboratorio di Neuroscienze cognitive e dello sviluppo del Dipartimento di Psicologia Generale dell'Università degli Studi di Padova. L’obiettivo della ricerca è stato quello di valutare gli effetti a breve termine del gioco sulle competenze cognitive e sociali dei bambini, concentrandosi in particolare sull’attenzione visuo-spaziale. Inoltre, si voleva valutare anche il ruolo del divertimento e delle emozioni sulle funzioni cognitive coinvolte nei futuri apprendimenti scolastici. L’ipotesi di partenza è stata che il gioco producesse uno stato di attivazione capace di portare ad un miglioramento delle prestazioni e delle capacità cognitive. Per raggiungere lo scopo è stata svolta una ricerca in doppio cieco in cui i dati sono stati raccolti in tre incontri: un momento di baseline seguito da due sessioni di gioco di 30 minuti ciascuna, la prima con un videogioco d’azione, la seconda, invece con un gioco da tavolo tradizionale, dopo le quali i bambini sono stati nuovamente valutati. Lo studio ha coinvolto 45 bambini di età prescolare presso due scuole dell’infanzia ai quali sono stati somministrati un test di valutazione del funzionamento cognitivo generale, un compito di ricerca visiva per valutare le capacità visuo-attentive ed un questionario sulle emozioni post gioco. Dall’analisi dei risultati è emerso che il Central Executive Network, che controlla la ricerca visiva complessa, è stato disturbato dal gioco che, invece, ha portato ad una maggiore efficienza dei centri automatici di elaborazione del Salience Network. Tuttavia, gli studi suggeriscono che, in seguito al momento stressante generato dall'esperienza ludica, si verifica una riallocazione delle risorse energetiche a favore della rete esecutiva di controllo che porterebbe ad un potenziamento delle funzioni cognitive a lungo termine

Impact of impurities and cryoconite on the optical properties of the Morteratsch Glacier (Swiss Alps)

Abstract. The amount of reflected energy by snow and ice plays a fundamental role in their melting processes. Different non-ice materials (carbonaceous particles, mineral dust (MD), microorganisms, algae, etc.) can decrease the reflectance of snow and ice promoting the melt. The object of this paper is to assess the capability of field and satellite (EO-1 Hyperion) hyperspectral data to characterize the impact of light-absorbing impurities (LAIs) on the surface reflectance of ice and snow of the Vadret da Morteratsch, a large valley glacier in the Swiss Alps. The spatial distribution of both narrow-band and broad-band indices derived from Hyperion was analyzed in relation to ice and snow impurities. In situ and laboratory reflectance spectra were acquired to characterize the optical properties of ice and cryoconite samples. The concentrations of elemental carbon (EC), organic carbon (OC) and levoglucosan were also determined to characterize the impurities found in cryoconite. Multi-wavelength absorbance spectra were measured to compare the optical properties of cryoconite samples and local moraine sediments. In situ reflectance spectra showed that the presence of impurities reduced ice reflectance in visible wavelengths by 80–90 %. Satellite data also showed the outcropping of dust during the melting season in the upper parts of the glacier, revealing that seasonal input of atmospheric dust can decrease the reflectance also in the accumulation zone of the glacier. The presence of EC and OC in cryoconite samples suggests a relevant role of carbonaceous and organic material in the darkening of the ablation zone. This darkening effect is added to that caused by fine debris from lateral moraines, which is assumed to represent a large fraction of cryoconite. Possible input of anthropogenic activity cannot be excluded and further research is needed to assess the role of human activities in the darkening process of glaciers observed in recent years

APPLICATION OF INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS ON ICE CORE SAMPLES

A first application of INAA (Instrumental Neutron Activation Analysis) to ice core sample

Mountain glaciers darkening: geochemical characterizazion of cryoconites and their radiative impact on the Vadret da Morteratsch (Swiss Alps)

Mountain glaciers represent an important source of fresh water across the globe. It is well known that these reservoirs are seriously threatened by global climate change, and a widespread reduction of glacier extension has been observed in recent years. Surface processes that promote ice melting are driven both by air temperature/precipitation and surface albedo. This latter is mainly influenced by the growth of snow grains and by the impurities content (such as mineral dust, soot, ash etc.). The origin of these light-absorbing impurities can be local or distal, and often, as a consequence of melting processes, they can aggregate on the glacier tongue, forming characteristics cryoconites, that decrease ice albedo and hence promote the melting. In this contribution, we coupled satellite images (EO1 \u2013 Hyperion and Landsat 8 - OLI) and ground hyperspectral data (ASD field spectrometer) for characterizing ice and snow surface reflectance of the Vadret da Morteratsch glacier (Swiss Alps). On the glacier ablation zone, we sampled ice, snow, surface dust and cryoconite material. To evaluate the possible impact of anthropogenic and natural emissions on cryoconites formation, we determined their geochemical composition (through the Neutron Activation Analysis, NAA) and the concentration of Black Carbon (BC), Organic Carbon (OC), Elemental Carbon (EC) and Levoglucosan. From satellite data, we computed the Snow Darkening Index (SDI), which is non-linearly correlated with dust content in snow. Results showed that, during 2015 summer season, ice albedo in the ablation zone reached very low values of about 0.1-0.2. The darkening of the glacier can be attributed to the impact of surface dust (from lateral moraine and Saharan desert) and cryoconites, coupled with grain growth driven by the extremely warm 2015 summer. The geochemical characterization of non-ice material contained in the cryoconites can provide important information regarding their source and the possible impact of anthropogenic emissions on cryoconites formation and evolution

Cryoconite as a temporary sink for anthropogenic species stored in glaciers

Cryoconite, the typical sediment found on the surface of glaciers, is mainly known in relation to its role in glacial microbiology and in altering the glacier albedo. But if these aspects are relatively well addressed, the same cannot be said about the geochemical properties of cryoconite and the possible interactions with glacial and peri-glacial environment. Current glacier retreat is responsible for the secondary emission of species deposited in high-altitude regions in the last decades. The role played by cryoconite in relation to such novel geochemical fluxes is largely unknown. Few and scarce observations suggest that it could interact with these processes, accumulating specific substances, but why, how and to what extent remain open questions. Through a multi-disciplinary approach we tried to shed lights. Results reveal that the peculiar composition of cryoconite is responsible for an extreme accumulation capability of this sediment, in particular for some, specific, anthropogenic substances

Deep ice as a geochemical reactor: Insights from iron speciation and mineralogy of dust in the Talos Dome ice core (East Antarctica)

Thanks to its insolubility, mineral dust is considered a stable proxy in polar ice cores. With this study we show that the Talos Dome ice core (TALDICE, Ross Sea sector of East Antarctica) displays evident and progressive signs of post-depositional processes affecting the mineral dust record below 1000g m deep. We apply a suite of established and cutting-edge techniques to investigate the properties of dust in TALDICE, ranging from concentration and grain size to elemental composition and Fe mineralogy. Results show that through acidic/oxidative weathering, the conditions of deep ice at Talos Dome promote the dissolution of specific minerals and the englacial formation of others, affecting primitive dust features. The expulsion of acidic atmospheric species from ice grains and their concentration in localized environments is likely the main process responsible for englacial reactions. Deep ice can be seen as a "geochemical reactor"capable of fostering complex reactions which involve both soluble and insoluble impurities. Fe-bearing minerals can efficiently help in exploring such transformations

Mineralogical study of rodingitized microgabbros and associated chromitite seams from the Nain ophiolite, Central Iran

The Nain-Dehshir-Baft Ophiolitic Belt (NDBOB), which crops out along the Nain-Baft fault, around the Central Iranian Microcontinent (CIM), comprises a set of dismembered ultramafic, mafic and sedimentary complexes. The northernmost branch of this ophiolitic belt is known as \u201cNain ophiolitic m\ue9lange\u201d and hosts small chromitite bodies, as pods and lenses, within completely serpentinized peridotites. The focus of the present study is the interaction between a 50 cm thick chromitite lens and a crosscutting rodingite dyke. For this purpose, a full transect across chromitite, rodingite and serpentinite was continuously sampled and studied in reflected and transmitted light microscopy. Mineral chemistry of sulfides, silicates, carbonates and oxydes was determined through EMP analyses. Rodingite shows a calc-silicate assemblage with an association of clinopyroxene, xonotlite, chlorite, garnet, vesuvianite, titanite, hornblende and chromite. Chromitite has 60-80% modal chromite, that sporadically shows a slight Fe-chromitization. Silicate assemblage is dominated by serpentine with relics of olivine and, occasionally, diopside, enstatite, hornblende and phlogopite. Later calcite veins crosscut both rodingite and chromitite, extending within serpentinite too. Rodingite shows a widespread range of copper sulfides, the most common ones being chalcocite, followed by native copper, digenite, geerite, and few spotted grains of possible yarrowite and sponkiopite. As secondary Cu oxydes and hydroxydes tenorite and spertiinite were found. In chromitite, close to the upper contact with rodingite, usual secondary sulfides like heazlewoodite and millerite were found together with shandite. Close to the lower rodingite contact, the presence of pyrrhotite, native iron and pentlandite was detected. Very close to the lower contact, again an unusual sulfide assemblage was found, with bornite and galena. Within rodingite clinopyroxenes show both diopside and augite compositions, with XMg ((Mg/(Mg+Fe2+)) of 0.93-0.96 for the former and 0.82-0.86 for the latter. Garnets are grossular and hydrogrossular in the upper rodingite, to which andradite is added in the lower rodingite. Chlorite shows a wide range of compositions with XMg increasing towards the contact with chomitite from 0.47 to 0.60. Very close to the contact XMg of chlorite ranges between 0.67 and 0.94. Chromite accessory grains have XMg ranging between 0.52 and 0.68 and XCr (Cr/(Cr+Al)) ranging between 0.75 and 0.80. Chromite in chromitite has XMg ranging between 0.65 and 0.71 and XCr ranging between 0.68 and 0.71. Olivine is forsteritic with XMg ranging between 0.95 and 0.97 and orthopyroxene is enstatitic with XMg around 0.94-0.95. Chlorite is very rare and has around 3.5 wt% Cr2O3. Rodingite intrusion postdates serpentinization of mantle assemblage and did not affect the chomite+silicate chromitite assemblage. The effect on sulfide variety and distribution was instead remarkable. At least lead and copper were introduced in the contact zone within chromitite to form shandite and bornite. Reducing conditions during rodingite emplacement are witnessed by the abundance of native copper and the presence of native iron. The effect of interaction in rodingite is mainly recorded by the wide range of chlorite compostions that increases its Mg content towards chromitite