361 research outputs found

    Exceptional Evolutionary Expansion of Prefrontal Cortex in Great Apes and Humans

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    One of the enduring questions that has driven neuroscientific enquiry in the last century has been the nature of differences in the prefrontal cortex of humans versus other animals [1]. The prefrontal cortex has drawn particular interest due to its role in a range of evolutionarily specialized cognitive capacities such as language [2], imagination [3], and complex decision making [4]. Both cytoarchitectonic [5] and comparative neuroimaging [6] studies have converged on the conclusion that the proportion of prefrontal cortex in the human brain is greatly increased relative to that of other primates. However, considering the tremendous overall expansion of the neocortex in human evolution, it has proven difficult to ascertain whether this extent of prefrontal enlargement follows general allometric growth patterns, or whether it is exceptional [1]. Species’ adherence to a common allometric relationship suggests conservation through phenotypic integration, while species’ deviations point toward the occurrence of shifts in genetic and/or developmental mechanisms. Here we investigate prefrontal cortex scaling across anthropoid primates and find that great ape and human prefrontal cortex expansion are non-allometrically derived features of cortical organization. This result aligns with evidence for a developmental heterochronic shift in human prefrontal growth [7, 8], suggesting an association between neurodevelopmental changes and cortical organization on a macroevolutionary scale. The evolutionary origin of non-allometric prefrontal enlargement is estimated to lie at the root of great apes (∌19–15 mya), indicating that selection for changes in executive cognitive functions characterized both great ape and human cortical organization

    Quantum phase transition in a single-molecule quantum dot

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    Quantum criticality is the intriguing possibility offered by the laws of quantum mechanics when the wave function of a many-particle physical system is forced to evolve continuously between two distinct, competing ground states. This phenomenon, often related to a zero-temperature magnetic phase transition, can be observed in several strongly correlated materials such as heavy fermion compounds or possibly high-temperature superconductors, and is believed to govern many of their fascinating, yet still unexplained properties. In contrast to these bulk materials with very complex electronic structure, artificial nanoscale devices could offer a new and simpler vista to the comprehension of quantum phase transitions. This long-sought possibility is demonstrated by our work in a fullerene molecular junction, where gate voltage induces a crossing of singlet and triplet spin states at zero magnetic field. Electronic tunneling from metallic contacts into the C60\rm{C_{60}} quantum dot provides here the necessary many-body correlations to observe a true quantum critical behavior.Comment: 8 pages, 5 figure

    Abnormalities in Osteoclastogenesis and Decreased Tumorigenesis in Mice Deficient for Ovarian Cancer G Protein-Coupled Receptor 1

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    Ovarian cancer G protein-coupled receptor 1 (OGR1) has been shown to be a proton sensing receptor in vitro. We have shown that OGR1 functions as a tumor metastasis suppressor gene when it is over-expressed in human prostate cancer cells in vivo. To examine the physiological functions of OGR1, we generated conditional OGR1 deficient mice by homologous recombination. OGR1 deficient mice were viable and upon gross-inspection appeared normal. Consistent with in vitro studies showing that OGR1 is involved in osteoclastogenesis, reduced osteoclasts were detected in OGR1 deficient mice. A pH-dependent osteoclasts survival effect was also observed. However, overall abnormality in the bones of these animals was not observed. In addition, melanoma cell tumorigenesis was significantly inhibited in OGR1 deficient mice. OGR1 deficient mice in the mixed background produced significantly less peritoneal macrophages when stimulated with thioglycolate. These macrophages also showed altered extracellular signal-regulated kinases (ERK) activation and nitric oxide (NO) production in response to lipopolysaccharide. OGR1-dependent pH responses assessed by cAMP production and cell survival in macrophages or brown fat cells were not observed, presumably due to the presence of other proton sensing receptors in these cells. Our results indicate that OGR1's role in osteoclastogenesis is not strong enough to affect overall bone development and its role in tumorigenesis warrants further investigation. The mice generated can be potentially used for several disease models, including cancers or osteoclast-related diseases

    Long-term passive acoustic recordings track the changing distribution of North Atlantic right whales (Eubalaena glacialis) from 2004 to 2014

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    © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 7 (2017): 13460, doi:10.1038/s41598-017-13359-3.Given new distribution patterns of the endangered North Atlantic right whale (NARW; Eubalaena glacialis) population in recent years, an improved understanding of spatio-temporal movements are imperative for the conservation of this species. While so far visual data have provided most information on NARW movements, passive acoustic monitoring (PAM) was used in this study in order to better capture year-round NARW presence. This project used PAM data from 2004 to 2014 collected by 19 organizations throughout the western North Atlantic Ocean. Overall, data from 324 recorders (35,600 days) were processed and analyzed using a classification and detection system. Results highlight almost year-round habitat use of the western North Atlantic Ocean, with a decrease in detections in waters off Cape Hatteras, North Carolina in summer and fall. Data collected post 2010 showed an increased NARW presence in the mid-Atlantic region and a simultaneous decrease in the northern Gulf of Maine. In addition, NARWs were widely distributed across most regions throughout winter months. This study demonstrates that a large-scale analysis of PAM data provides significant value to understanding and tracking shifts in large whale movements over long time scales.This research was funded and supported by many organizations, specified by projects as follows: Data recordings from region 1 were provided by K. Stafford and this research effort was funded by the National Science Foundation #NSF-ARC 0532611. Region 2 data were provided by D. K. Mellinger and S. Nieukirk, funded by National Oceanic and Atmospheric Agency (NOAA) and the Office of Naval Research (ONR) #N00014–03–1–0099, NOAA #NA06OAR4600100, US Navy #N00244-08-1-0029, N00244-09-1-0079, and N00244-10-1-0047

    Tunneling Spectra of Individual Magnetic Endofullerene Molecules

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    The manipulation of single magnetic molecules may enable new strategies for high-density information storage and quantum-state control. However, progress in these areas depends on developing techniques for addressing individual molecules and controlling their spin. Here we report success in making electrical contact to individual magnetic N@C60 molecules and measuring spin excitations in their electron tunneling spectra. We verify that the molecules remain magnetic by observing a transition as a function of magnetic field which changes the spin quantum number and also the existence of nonequilibrium tunneling originating from low-energy excited states. From the tunneling spectra, we identify the charge and spin states of the molecule. The measured spectra can be reproduced theoretically by accounting for the exchange interaction between the nitrogen spin and electron(s) on the C60 cage.Comment: 7 pages, 4 figures. Typeset in LaTeX, updated text of previous versio

    A new methodological contribution for the geodiversity assessment: applicability to CearĂĄ State (Brazil)

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    The concept of geodiversity aggregates the abiotic elements of nature and promotes the geoconservation. The main objective of this work is to contribute to the upgrade of the method for the assessment and quantification of geodiversity proposed by Pereira et al. (2013). The method is based on the superposition of a regular grid of 12 × 12 km on different maps (lithology, geomorphology, soil, paleonthology, mineral and geological energy resources) at scales of 1:250,000 to 1:600,000. In addition to other up- grades, the water resources are regarded here as a new com- ponent to consider when quantifying geodiversity. The sum of these maps generated the quantitative Map of Geodiversity Indices and the Map of Geodiversity Assessment, ranging from very low to very high geodiversity. The analysis of the geodiversity map of the State of CearĂĄ (Brazil) shows the applicability and advantage of this method, highlighting two regions with higher levels of geodiversity (Northwest and South) and another region with the lowest levels (SertĂ”es Cearenses). The results also allowed the characterization of the State of CearĂĄ concerning the individual components of the geodiversity, especially the water resources. Geodiversity indices and maps are comprehensive and user-friendly data in the territorial planning, considering the geodiversity either as a whole, or each of its components, especially the more sensi- tive such as fossil conservation, and water, mineral, and non- renewable energy resources management.The authors express their gratitude to the Brazilian research fostering institution "Coordenação de Aperfeiçoamento de Pessoal de NĂ­vel Superior" (CAPES) for awarding the CiĂȘncia Sem Fronteiras (CsF) PhD scholarship that enabled this work. This work was partially co-funded by the European Union through the European Regional Development Fund, based on COMPETE 2020 (Programa Operacional da Competitividade e Internacionalização), project ICT (UID/GEO/04683/ 2013) with reference POCI-01-0145-FEDER-007690 and national funds provided by Fundação para a CiĂȘncia e Tecnologia

    Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV

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    Inclusive transverse momentum spectra of primary charged particles in Pb-Pb collisions at sNN\sqrt{s_{_{\rm NN}}} = 2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross section. The measured charged particle spectra in ∣η∣<0.8|\eta|<0.8 and 0.3<pT<200.3 < p_T < 20 GeV/cc are compared to the expectation in pp collisions at the same sNN\sqrt{s_{\rm NN}}, scaled by the number of underlying nucleon-nucleon collisions. The comparison is expressed in terms of the nuclear modification factor RAAR_{\rm AA}. The result indicates only weak medium effects (RAA≈R_{\rm AA} \approx 0.7) in peripheral collisions. In central collisions, RAAR_{\rm AA} reaches a minimum of about 0.14 at pT=6p_{\rm T}=6-7GeV/cc and increases significantly at larger pTp_{\rm T}. The measured suppression of high-pTp_{\rm T} particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb-Pb collisions at the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98

    Two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

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    The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/388

    Systematic Screening of Drosophila Deficiency Mutations for Embryonic Phenotypes and Orphan Receptor Ligands

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    This paper defines a collection of Drosophila deletion mutations (deficiencies) that can be systematically screened for embryonic phenotypes, orphan receptor ligands, and genes affecting protein localization. It reports the results of deficiency screens we have conducted that have revealed new axon guidance phenotypes in the central nervous system and neuromuscular system and permitted a quantitative assessment of the number of potential genes involved in regulating guidance of specific motor axon branches. Deficiency “kits” that cover the genome with a minimum number of lines have been established to facilitate gene mapping. These kits cannot be systematically analyzed for phenotypes, however, since embryos homozygous for many deficiencies in these kits fail to develop due to the loss of key gene products encoded within the deficiency. To create new kits that can be screened for phenotype, we have examined the development of the nervous system in embryos homozygous for more than 700 distinct deficiency mutations. A kit of ∌400 deficiency lines for which homozygotes have a recognizable nervous system and intact body walls encompasses >80% of the genome. Here we show examples of screens of this kit for orphan receptor ligands and neuronal antigen expression. It can also be used to find genes involved in expression, patterning, and subcellular localization of any protein that can be visualized by antibody staining. A subset kit of 233 deficiency lines, for which homozygotes develop relatively normally to late stage 16, covers ∌50% of the genome. We have screened it for axon guidance phenotypes, and we present examples of new phenotypes we have identified. The subset kit can be used to screen for phenotypes affecting all embryonic organs. In the future, these deficiency kits will allow Drosophila researchers to rapidly and efficiently execute genome-wide anatomical screens that require examination of individual embryos at high magnification

    Multifunctional biophotonic nanostructures inspired by the longtail glasswing butterfly for medical devices

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    Numerous living organisms possess biophotonic nanostructures that provide colouration and other diverse functions for survival. While such structures have been actively studied and replicated in the laboratory, it remains unclear whether they can be used for biomedical applications. Here, we show a transparent photonic nanostructure inspired by the longtail glasswing butterfly (Chorinea faunus) and demonstrate its use in intraocular pressure (IOP) sensors in vivo. We exploit the phase separation between two immiscible polymers (poly(methyl methacrylate) and polystyrene) to form nanostructured features on top of a Si3_N_4 substrate. The membrane thus formed shows good angle-independent white-light transmission, strong hydrophilicity and anti-biofouling properties, which prevent adhesion of proteins, bacteria and eukaryotic cells. We then developed a microscale implantable IOP sensor using our photonic membrane as an optomechanical sensing element. Finally, we performed in vivo testing on New Zealand white rabbits, which showed that our device reduces the mean IOP measurement variation compared with conventional rebound tonometry without signs of inflammation
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