74 research outputs found
Planck scale effects in neutrino physics
We study the phenomenology and cosmology of the Majoron (flavon) models of
three active and one inert neutrino paying special attention to the possible
(almost) conserved generalization of the Zeldovich-Konopinski-Mahmoud lepton
charge. Using Planck scale physics effects which provide the breaking of the
lepton charge, we show how in this picture one can incorporate the solutions to
some of the central issues in neutrino physics such as the solar and
atmospheric neutrino puzzles, dark matter and a 17 keV neutrino. These
gravitational effects induce tiny Majorana mass terms for neutrinos and
considerable masses for flavons. The cosmological demand for the sufficiently
fast decay of flavons implies a lower limit on the electron neutrino mass in
the range of 0.1-1 eV.Comment: 24 pages, 1 figure (not included but available upon request), LaTex,
IC/92/196, SISSA-140/92/EP, LMU-09/9
Rapid and highly variable warming of lake surface waters around the globe
In this first worldwide synthesis of in situ and satellite-derived lake data, we find that lake summer surface water temperatures rose rapidly (global mean = 0.34°C decade−1) between 1985 and 2009. Our analyses show that surface water warming rates are dependent on combinations of climate and local characteristics, rather than just lake location, leading to the counterintuitive result that regional consistency in lake warming is the exception, rather than the rule. The most rapidly warming lakes are widely geographically distributed, and their warming is associated with interactions among different climatic factors—from seasonally ice-covered lakes in areas where temperature and solar radiation are increasing while cloud cover is diminishing (0.72°C decade−1) to ice-free lakes experiencing increases in air temperature and solar radiation (0.53°C decade−1). The pervasive and rapid warming observed here signals the urgent need to incorporate climate impacts into vulnerability assessments and adaptation efforts for lakes.Peer reviewe
A global database of lake surface temperatures collected by in situ and satellite methods from 1985–2009
Peer reviewe
Densidade, tamanho e distribuição estomática em 35 espécies de árvores na Amazônia Central
Stomata are turgor-operated valves that control water loss and CO2 uptake during photosynthesis, and thereby water relation and plant biomass accumulation is closely related to stomatal functioning. The aims of this work were to document how stomata are distributed on the leaf surface and to determine if there is any significant variation in stomatal characteristics among Amazonian tree species, and finally to study the relationship between stomatal density (S D) and tree height. Thirty five trees (>17 m tall) of different species were selected. Stomatal type, density (S D), size (S S) and stomatal distribution on the leaf surface were determined using nail polish imprints taken from both leaf surfaces. Irrespective of tree species, stomata were located only on the abaxial surface (hypostomaty), with large variation in both S D and S S among species. S D ranged from 110 mm-2 in Neea altissima to 846 mm-2 in Qualea acuminata. However, in most species S D ranges between 271 and 543 mm-2, with a negative relationship between S D and S S. We also found a positive relationship between S D and tree height (r² = 0.14, p 17 m de altura) de diferentes espécies foram selecionadas. Tipo de complexo estomático, S D, tamanho (S S) e distribuição na superfície foliar foram determinados utilizando impressões de ambas as superfícies foliares com esmalte incolor. Independente da espécie, os estômatos foram encontrados apenas na superfície abaxial (hipoestomatia) com ampla variação na S D e no S S entre espécies. A densidade estomática variou de 110 mm-2 em Neea altissima a 846 mm-2 em Qualea acuminata. Entretanto, a maioria das espécies apresentou S D entre 271 e 543 mm-2, com uma relação negativa entre S D e S S. Observou-se uma relação positiva entre S D e altura arbórea (r² = 0.14, p < 0.01), não havendo relação entre S D e espessura foliar. Os tipos estomáticos mais comuns foram: anomocíticos (37%), seguidos de paracíticos (26%) e anisocíticos (11%). Concluiu-se que em espécies da Amazônia, a distribuição de estômatos na superfície foliar está mais relacionada a fatores genéticos de cada espécie do que a variações ambientais. Entretanto, S D é fortemente influenciada por fatores ambientais concernentes à altura da árvore
Rapid and highly variable warming of lake surface waters around the globe
peer reviewedIn this first worldwide synthesis of in situ and satellite-derived lake data, we find that lake summer surface water temperatures rose rapidly (global mean = 0.34°C decade-1) between 1985 and 2009. Our analyses show that surface water warming rates are dependent on combinations of climate and local characteristics, rather than just lake location, leading to the counterintuitive result that regional consistency in lake warming is the exception, rather than the rule. The most rapidly warming lakes are widely geographically distributed, and their warming is associated with interactions among different climatic factors - from seasonally ice-covered lakes in areas where temperature and solar radiation are increasing while cloud cover is diminishing (0.72°C decade-1) to ice-free lakes experiencing increases in air temperature and solar radiation (0.53°C decade-1). The pervasive and rapid warming observed here signals the urgent need to incorporate climate impacts into vulnerability assessments and adaptation efforts for lakes. © 2015. American Geophysical Union. All Rights Reserved
Rapid and highly variable warming of lake surface waters around the globe
Peer reviewed. ©2015. The Authors.This is an open access article under theterms of the Creative CommonsAttribution-NonCommercial-N oDerivsLicense, which permits use and distri-bution in any medium, provided theoriginal work is properly cited, the use isnon-commerc ial and no modificationsor adaptations are made.In this first worldwide synthesis of in situ and satellite-derived lake data, we find that lake summer surface water temperatures rose rapidly (global mean = 0.34°C decade 1) between 1985 and 2009. Our analyses show that surface water warming rates are dependent on combinations of climate and
local characteristics, rather than just lake location, leading to the counterintuitive result that regional consistency in lake warming is the exception, rather than the rule. The most rapidly warming lakes are widely geographically distributed, and their warming is associated with interactions among different climatic factors —from seasonally ice-covered lakes in areas where temperature and solar radiation are increasing while cloud cover is diminishing (0.72°C decade 1) to ice-free lakes experiencing increases in air temperature
and solar radiation (0.53°C decade 1). The pervasive and rapid warming observed here signals the urgent need to incorporate climate impacts into vulnerability assessments and adaptation efforts for lakes
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The Soft X-ray Imager (SXI) on the SMILE Mission
The Soft X-ray Imager (SXI) is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) mission. SMILE is a joint science mission between the European Space Agency (ESA) and the Chinese Academy of Sciences (CAS) and is due for launch in 2025. SXI is a compact X-ray telescope with a wide field-of-view (FOV) capable of encompassing large portions of Earth’s magnetosphere from the vantage point of the SMILE orbit. SXI is sensitive to the soft X-rays produced by the Solar Wind Charge eXchange (SWCX) process produced when heavy ions of solar wind origin interact with neutral particles in Earth’s exosphere. SWCX provides a mechanism for boundary detection within the magnetosphere, such as the position of Earth’s magnetopause, because the solar wind heavy ions have a very low density in regions of closed magnetic field lines. The sensitivity of the SXI is such that it can potentially track movements of the magnetopause on timescales of a few minutes and the orbit of SMILE will enable such movements to be tracked for segments lasting many hours. SXI is led by the University of Leicester in the United Kingdom (UK) with collaborating organisations on hardware, software and science support within the UK, Europe, China and the United States
Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses
To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1–11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely
Radioactive waste disposals from nuclear sites in Scotland 1980-1983
0.50SIGLEAvailable from British Library Document Supply Centre- DSC:8447.675(May 1984) / BLDSC - British Library Document Supply CentreGBUnited Kingdo
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