Rare Earth Elements of modern shelf and deep-water articulated brachiopods: evaluation of seawater masses

Modern Rhynchonellids and Tcrcbratulids, obtained from water depths below the neritic zone (>500m) at 23 stations in the Caribbean Sea, North Atlantic, South Pacific and Southern Oceans, were investigated for their rare earth clement (REE) contents (Fig. I, Table I). The ΣREE of shelf (500-I 000 m) or deep-water (> I 000 m) brachiopod populations do not vary significantly between oceans/seas irrespective of water mass origins or influences by major currents

Að ástunda heimspekisögu : Af angurleysi fornaldar

Fræðimenn sem hafa fengist við heimspekisögu síðustu áratugi hafa margir áréttað mikilvægi þess að leita skilnings á viðfangsefni sínu svo sem kostur er á forsendum þess tíma sem um er fjallað en ekki (aðeins) á forsendum þess tíma sem fræðimennirnir sjálfir tilheyra. Þannig yrði skilningurinn dýpri. Hér verður tekið dæmi af umfjöllun fræðimanna um kenningar nokkurra grískra fornaldarheimspekinga um angurleysi (ataraxía). Fyrst eru kenningarnar raktar og skýrðar. Þá eru helstu viðbrögð fræðimanna við þessum kenningum skoðuð. Þessi viðbrögð afhjúpa viðhorf um hvað eiginleg heimspeki sé, að minnsta kosti eiginleg fornaldarheimspeki. Viðbrögðin einkennast annað hvort af neikvæðum gildisdómum, því ekki sé um eiginlega heimspeki að ræða, eða tilraunum til að skýra burt vitnisburðinn, því hann samræmist ekki eiginlegri heimspeki. Hvort tveggja skekkir skilning okkar á viðfangsefninu.Peer reviewe

The role of low-energy electron interactions in cis-pt(Co)2 br2 fragmentation

Funding Information: Funding: This project was conducted within the framework of ELENA, a Horizon 2020 research and innovation program under Marie Sklodowska-Curie Innovative Training Network, under the grant agreement No. 722149. M.C. and O.I. acknowledge support from the Icelandic Center of Research (RANNIS), grant no. 13049305(1−3). M.C. acknowledges a doctoral grant from the University of Iceland Research Fund. H.L. and L.M.-W. thank the National Science Foundation for support under grants CHE-1607547 and CHE-1904802. F.F.d.S. acknowledges the Portuguese National Funding Agency for Science Research and Technology (FCT-MCTES), through the research grants PTDC/FIS-AQM/31215/2017 and UIDB/00068/2020 (CEFITEC). Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Platinum coordination complexes have found wide applications as chemotherapeutic anticancer drugs in synchronous combination with radiation (chemoradiation) as well as precursors in focused electron beam induced deposition (FEBID) for nano-scale fabrication. In both applications, low-energy electrons (LEE) play an important role with regard to the fragmentation pathways. In the former case, the high-energy radiation applied creates an abundance of reactive photo-and secondary electrons that determine the reaction paths of the respective radiation sensitizers. In the latter case, low-energy secondary electrons determine the deposition chemistry. In this contribution, we present a combined experimental and theoretical study on the role of LEE interactions in the fragmentation of the Pt(II) coordination compound cis-PtBr2 (CO)2. We discuss our results in conjunction with the widely used cancer therapeutic Pt(II) coordination compound cis-Pt(NH3)2 Cl2 (cisplatin) and the carbonyl analog Pt(CO)2 Cl2, and we show that efficient CO loss through dissociative electron attachment dominates the reactivity of these carbonyl complexes with low-energy electrons, while halogen loss through DEA dominates the reactivity of cis-Pt(NH3)2 Cl2.publishersversionpublishe

Call combination patterns in Icelandic killer whales (Orcinus orca)

Funding: Funding for data collection was provided by the Fundação para a Ciência e a Tecnologia (grant number SFRH/BD/30303/2006), the Icelandic Research Fund (grant numbers 120248042 and 217519), the National Geographic Global Exploration Fund (grant number GEFNE65-12), and a Russell Trust Award from the University of St. Andrews to FIPS. This project was funded in part by the generous support of Earthwatch. Additionally, funding was provided by the US Office of Naval Research (grant number N00014-08-1-0984), US Living Marine Resources (project 57), UK Defence Science and Technology Laboratory, and French Direction Générale de l’Armement to PJOM. A RANNÍS Infrastructure Fund (grant number 200229) provided funding to JS and PJW for CATS tags and tracking equipment. AS was supported by Doctoral Student Grants (grant number 206808 and 239641) from the Icelandic Research Fund.Acoustic sequences have been described in a range of species and in varying complexity. Cetaceans are known to produce complex song displays but these are generally limited to mysticetes; little is known about call combinations in odontocetes. Here we investigate call combinations produced by killer whales (Orcinus orca), a highly social and vocal species. Using acoustic recordings from 22 multisensor tags, we use a first order Markov model to show that transitions between call types or subtypes were significantly different from random, with repetitions and specific call combinations occurring more often than expected by chance. The mixed call combinations were composed of two or three calls and were part of three call combination clusters. Call combinations were recorded over several years, from different individuals, and several social clusters. The most common call combination cluster consisted of six call (sub-)types. Although different combinations were generated, there were clear rules regarding which were the first and last call types produced, and combinations were highly stereotyped. Two of the three call combination clusters were produced outside of feeding contexts, but their function remains unclear and further research is required to determine possible functions and whether these combinations could be behaviour- or group-specific.Publisher PDFPeer reviewe

OH−^- ions can reduce the iodide migration in MAPI

One of the main degradation mechanisms of methylammonium lead iodine (MAPI), which is an important material for perovskite based solar cells, is the migration of iodide ions. It is believed that this phenomenon is in fact dominated by the diffusion of iodide vacancies. In this paper, we suggest that the addition of a small amount of OH$^-$ ions can help suppress the migration of iodide and increase the overall stability of the material. Through the use of molecular dynamics simulations, we show that the OH$^-$ ions can bind to the positively charged iodide vacancies and can block the access of the negative iodide ions into those vacancies.Comment: 2023 International Semiconductor Conference (CAS), Sinaia, Romani

Adding pieces to the puzzle: insights into diversity and distribution patterns of Cumacea (Crustacea: Peracarida) from the deep North Atlantic to the Arctic Ocean

The Nordic Seas have one of the highest water-mass diversities in the world, yet large knowledge gaps exist in biodiversity structure and biogeographical distribution patterns of the deep macrobenthic fauna. This study focuses on the marine bottom-dwelling peracarid crustacean taxon Cumacea from northern waters, using a combined approach of morphological and molecular techniques to present one of the first insights into genetic variability of this taxon. In total, 947 specimens were assigned to 77 morphologically differing species, representing all seven known families from the North Atlantic. A total of 131 specimens were studied genetically (16S rRNA) and divided into 53 putative species by species delimitation methods (GMYC and ABGD). In most cases, morphological and molecular-genetic delimitation was fully congruent, highlighting the overall success and high quality of both approaches. Differences were due to eight instances resulting in either ecologically driven morphological diversification of species or morphologically cryptic species, uncovering hidden diversity. An interspecific genetic distance of at least 8% was observed with a clear barcoding gap for molecular delimitation of cumacean species. Combining these findings with data from public databases and specimens collected during different international expeditions revealed a change in the composition of taxa from a Northern Atlantic-boreal to an Arctic community. The Greenland-Iceland-Scotland-Ridge (GIS-Ridge) acts as a geographical barrier and/or predominate water masses correspond well with cumacean taxa dominance. A closer investigation on species level revealed occurrences across multiple ecoregions or patchy distributions within defined ecoregions.publishedVersio

Germanium coated silicon nanowires as human respiratory sensing device

Post-print (lokagerð höfundar)We report on germanium coated silicon nanowires structures synthesized with metal assisted chemical etching and qualify their functionality as human respiratory sensor. The sensors were made from p-type single-crystalline (100) silicon wafers using a silver catalyzed top-down etching, afterwards coated by 50 nm germanium thin layer using a magnetron sputtering. The germanium post-treatment was performed by rapid thermal annealing at 450 and 700◦C. The sensors were characterized by X-ray diffraction diffractogram and scanning electron microscopy. It is demonstrated that the sensors are highly sensitive as human breath detectors, with rapid response and frequency detectability. They are also shown to be a good candidate for human respiratory disease diagnoses.This work was supported by Reykjavik University Ph.D. fund no. 220006 and the Icelandic Research Fund Grant no. 218029-051. We are grateful to Rodica Plugaru and Neculai Plugaru for discussions.Peer review

Photoluminescence study of Si_1-xGe_x nanoparticles in various oxide matrices

We investigate the photoluminescence properties of structures comprising of Si1-xGex nanoparticles (NPs) within SiO2, GeO2, TiO2 and Ta2O5 oxide matrices. Of the investigated structures, it was observed that the structures with GeO2 and TiO2 matrices provide increased spectral response (at ~907 and 844 nm respectively) and increased PL intensity. The improved PL characteristic have been attributed to increased diffusion barrier against oxygen which otherwise would result in formation of unwanted oxide at the film-oxide interface, thereby deteriorating the optical properties.This work is partially funded by the Icelandic Research Fund Grants nos. 218029 and 196141.Pre-print (óritrýnt handrit

SiGe nanocrystals in SiO2 with high photosensitivity from visible to short-wave infrared

Publisher's version (útgefin grein)Films of SiGe nanocrystals (NCs) in oxide have the advantage of tuning the energy band gap by adjusting SiGe NCs composition and size. In this study, SiGe-SiO2 amorphous films were deposited by magnetron sputtering on Si substrate followed by rapid thermal annealing at 700, 800 and 1000 °C. We investigated films with Si:Ge:SiO2 compositions of 25:25:50 vol.% and 5:45:50 vol.%. TEM investigations reveal the major changes in films morphology (SiGe NCs with different sizes and densities) produced by Si:Ge ratio and annealing temperature. XPS also show that the film depth profile of SiGe content is dependent on the annealing temperature. These changes strongly influence electrical and photoconduction properties. Depending on annealing temperature and Si:Ge ratio, photocurrents can be 103 times higher than dark currents. The photocurrent cutoff wavelength obtained on samples with 25:25 vol% SiGe ratio decreases with annealing temperature increase from 1260 nm in SWIR for 700 °C annealed films to 1210 nm for those at 1000 °C. By increasing Ge content in SiGe (5:45 vol%) the cutoff wavelength significantly shifts to 1345 nm (800 °C annealing). By performing measurements at 100 K, the cutoff wavelength extends in SWIR to 1630 nm having high photoresponsivity of 9.35 AW−1.This work was supported by TE Contract no.30/2018 (PN-III-P1-1.1-TE-2016-2050, within PNCDI III), M-ERA.NET PhotoNanoP Contract No. 33/2016, PCE Contract No. 122/2017, PCCDI Contract No. 75/2018, and financed by CNCS-UEFISCDI, and by Romanian Ministry of Research and Innovation through NIMP Core Program PN19-03 (Contract No. 21N/08.02.2019)."Peer Reviewed