421 research outputs found
Bias to CMB lensing from lensed foregrounds
Extragalactic foregrounds are known to constitute a limiting systematic in temperature-based cosmic microwave background (CMB) lensing with AdvACT, SPT-3G, Simons Observatory, and CMB S4. Furthermore, since these foregrounds are emitted at cosmological distances, they are also themselves lensed. The correlation between this foreground lensing and CMB lensing causes an additional bias in CMB lensing estimators. In this paper, we quantify for the first time this "lensed foreground bias" for the standard CMB lensing quadratic estimator, the CMB shear, and the CMB magnification estimators, in the case of Simons Observatory and in the absence of multifrequency component separation. This percent-level bias is highly significant in the cross-correlation of CMB lensing with LSST galaxies and comparable to the statistical uncertainty in the CMB lensing autospectrum. We discuss various mitigation strategies and show that "lensed foreground bias-hardening" methods can reduce this bias at some cost in signal to noise. The code used to generate our theory curves is publicly available.1https://github.com/EmmanuelSchaan/LensedForegroundBias
Reconstruction with velocities
Reconstruction is becoming a crucial procedure of galaxy clustering analysis for future spectroscopic redshift surveys to obtain subper cent level measurement of the baryon acoustic oscillation scale. Most reconstruction algorithms rely on an estimation of the displacement field from the observed galaxy distribution. However, the displacement reconstruction degrades near the survey boundary due to incomplete data and the boundary effects extend to ∼100 Mpc/h within the interior of the survey volume. We study the possibility of using radial velocities measured from the cosmic microwave background observation through the kinematic Sunyaev-Zeldovich effect to improve performance near the boundary. We find that the boundary effect can be reduced to ∼30 − 40 Mpc/h with the velocity information from Simons Observatory. This is especially helpful for dense low redshift surveys where the volume is relatively small and a large fraction of total volume is affected by the boundary
Transdiciplinary Approach to the Follow-Up of Patients After Myocardial Infarction
OBJECTIVES: To compare conventional and transdisciplinary care in a tertiary outpatient clinic for patients after their first acute myocardial infarction. METHODS: One hundred fifty-three patients with acute myocardial infarction were randomized at hospital discharge and followed-up to compare conventional (n=75) and transdisciplinary care (n=78). They were submitted to a clinical evaluation, received a dietary plan, and were re-evaluated twice in 60-180 days by a nurse, dietitian and physician, when new clinical and laboratory data were collected. The primary outcome was clinical improvement, as evaluated by an index including reduction of body weight, lowering of blood pressure, smoking cessation, increase in physical activity and compliance with medication. RESULTS: The groups were similar at baseline: 63.4% were men, 89.9% had an acute myocardial infarction with ST-segment-elevation, 32.7% were diabetic, and 72.2% were hypertensive. The clinical improvement index was similar between the studied groups: in 33.3 % (transdisciplinary care) vs. 30.4 % (conventional care) of patients, the improvement was very good (P=1.000). Rates of re-hospitalization and death (p=0.127) were similar between transdisciplinary and conventional care. Compliance with diet was higher for transdisciplinary care (50.0%) vs. conventional care (26.1%) (p=0.007), as was compliance with visits (73.3 vs. 40.3%, respectively, p<0.001). CONCLUSIONS: Compliance with diet and visits was higher for transdisciplinary care vs. conventional care; however, the transdisciplinary approach did not provide more clinical benefits than the conventional approach after patients' first acute myocardial infarction in this setting
O registro arqueológico no solo: as ocupações humanas na Volta Grande do Xingú - Pará.
A região do médio Rio Xingu, na parte conhecida como Volta Grande do Xingu, tem um longo histórico de ocupação humana nas suas margens. Prospecções indicaram a existência de um grande número de sítios arqueológicos, e muitos desses com a presença de camadas de solos escurecidas, com a presença de artefatos cerâmicos e líticos. Os horizontes de solos modificados pelo homem, conhecidos na Amazônia como: as Terras Pretas de Índio (TPI). Essas áreas que aparentam ser sítios de habitação, se assentam em pequenos platôs em áreas planas. Como o objetivo de analisar as alterações causadas pelo Homem nas características do solo, foram avaliadas amostras de solo coletadas em diferentes camadas em dois perfis estratigráficos no Sitio Arqueológico Bom Jesus, localizado no município de Senador Porfirio - PA. As amostras foram analisadas quanto aos valores de susceptibilidade magnética (SM), teores semi totais utilizando a técnica de Indução de Plasma Acoplado (ICP-OES) para os teores de Ca, Fe, Mn, Mg, Zn, P, Ca, Mg, Sr e Ba e os teores totais de Ti, Fe, Zn, Mn, Cu e Sr utilizando a técnica da fluorescência de raios X (pXRF). Os resultados mostraram alterações na composição química com aumentos dos teores de P, Ca, Zn, Mn, Mg, Sr, Ba e Cu em várias camadas, em comparação com os valores suprajacentes dos perfis. Os aumentos da concentração destes elementos são causados pelas adições de resíduos orgânicos e manejo do ambiente. A elevada quantidade de fragmentos cerâmicos e líticos até mais de 50 cm de profundidade permite inferir uma longa e intensa ocupação do local. O aumento da SM nos horizontes antrópicos também corrobora uma ocupação intensa dessas áreas, com a elevação dos valores de SM provavelmente como consequência do aquecimento do solo abaixo de fogueiras e fornos para queima de cerâmica (fenômeno da termoremanência). A avaliação de parâmetros físico químicos e mineralógicos do solo pode auxiliar a delimitação dos sítios arqueológicos onde os artefatos são escassos ou inexistentes. Os horizontes de solos antrópicos são um registro das atividades humanas e podem ser considerados artefatos arqueológicos. A preservação deste legado de civilizações pretéritas é dever da nossa sociedade
Bradykinin or Acetylcholine as Vasodilators to Test Endothelial Venous Function in Healthy Subjects
INTRODUCTION: The evaluation of endothelial function has been performed in the arterial bed, but recently evaluation within the venous system has also been explored. Endothelial function studies employ different drugs that act as endothelium-dependent vasodilatory response inductors. OBJECTIVES: The aim of this study is to compare the endothelium-dependent venous vasodilator response mediated by either acetylcholine or bradykinin in healthy volunteers. METHODS AND RESULTS: Changes in vein diameter after phenylephrine-induced venoconstriction were measured to compare venodilation induced by acetylcholine or bradykinin (linear variable differential transformer dorsal hand vein technique). We studied 23 healthy volunteers; 31% were male, and the subject had a mean age of 33 ± 8 years and a mean body mass index of 23 ± 2 kg/m2. The maximum endothelium-dependent venodilation was similar for both drugs (p = 0.13), as well as the mean responses for each dose of both drugs (r = 0.96). The maximum responses to acetylcholine and bradykinin also had good agreement. CONCLUSION: There were no differences between acetylcholine and bradykinin as venodilators in this endothelial venous function investigation
Feições geomorfológicas e solos nos locais em que foram construídos os geoglifos no Estado do Acre.
Distribuição dos Geoglifos na Amazônia Ocidental. Relações Ambientais dos Geoglifos no Município de Plácido de Castro. Localização dos Geoglifos em Relação Às Feições Geomorfológicas. Localização dos Geoglifos em Relação às Classes e Características dos Solos. Ocorrência de Geoglifos em Argissolos. Ocorrência de Geoglifos em Latossolos. Ocorrência de Geoglifos em Plintossolos. Características dos Solos nos Geoglifos. Falta de Evidências de Sítios de Habitação no Interior dos Geoglifos
Detection of the pairwise kinematic Sunyaev-Zel'dovich effect with BOSS DR11 and the Atacama Cosmology Telescope
We present a new measurement of the kinematic Sunyaev-Zeldovich effect using
data from the Atacama Cosmology Telescope (ACT) and the Baryon Oscillation
Spectroscopic Survey (BOSS). Using 600 square degrees of overlapping sky area,
we evaluate the mean pairwise baryon momentum associated with the positions of
50,000 bright galaxies in the BOSS DR11 Large Scale Structure catalog. A
non-zero signal arises from the large-scale motions of halos containing the
sample galaxies. The data fits an analytical signal model well, with the
optical depth to microwave photon scattering as a free parameter determining
the overall signal amplitude. We estimate the covariance matrix of the mean
pairwise momentum as a function of galaxy separation, using microwave sky
simulations, jackknife evaluation, and bootstrap estimates. The most
conservative simulation-based errors give signal-to-noise estimates between 3.6
and 4.1 for varying galaxy luminosity cuts. We discuss how the other error
determinations can lead to higher signal-to-noise values, and consider the
impact of several possible systematic errors. Estimates of the optical depth
from the average thermal Sunyaev-Zeldovich signal at the sample galaxy
positions are broadly consistent with those obtained from the mean pairwise
momentum signal.Comment: 15 pages, 8 figures, 2 table
Recommended from our members
Historical ecology, human niche construction and landscape in pre-Columbian Amazonia: a case study of the geoglyph builders of Acre, Brazil
This paper applies concepts from the fields of historical ecology and human niche construction theory to interpret archaeological and palaeoecological data from the Brazilian state of Acre, southwest Amazonia, where modern deforestation has revealed hundreds of pre-Columbian monumental earthworks called 'geoglyphs', largely built between ca. 2000–650 cal. BP (calibrated years before present). Our main objective was to move away from the debate which currently dominates Amazonian archaeology over large- vs. small-scale pre-Columbian environmental impacts, and instead offer a more nuanced interpretation of human-environment interactions in our specific study area. Despite the difficulties presented by working with an incomplete regional archaeological dataset, interpreting our findings in light of these theoretical frameworks allowed us to re-think landscape history and ask new questions about a possible relationship between anthropogenic forests, symbolic capital and monument building in our particular study area
class_sz I: Overview
class_sz is a versatile and robust code in C and Python that can compute
theoretical predictions for a wide range of observables relevant to
cross-survey science in the Stage IV era. The code is public at
https://github.com/CLASS-SZ/class_sz along with a series of tutorial notebooks
(https://github.com/CLASS-SZ/notebooks). It will be presented in full detail in
paper II. Here we give a brief overview of key features and usage.Comment: to appear in Proc. of the mm Universe 2023 conference, Grenoble
(France), June 2023, published by F. Mayet et al. (Eds), EPJ Web of
conferences, EDP Science
Science Impacts of the SPHEREx All-Sky Optical to Near-Infrared Spectral Survey: Report of a Community Workshop Examining Extragalactic, Galactic, Stellar and Planetary Science
SPHEREx is a proposed SMEX mission selected for Phase A. SPHEREx will carry
out the first all-sky spectral survey and provide for every 6.2" pixel a
spectra between 0.75 and 4.18 m [with R41.4] and 4.18 and 5.00
m [with R135]. The SPHEREx team has proposed three specific science
investigations to be carried out with this unique data set: cosmic inflation,
interstellar and circumstellar ices, and the extra-galactic background light.
It is readily apparent, however, that many other questions in astrophysics and
planetary sciences could be addressed with the SPHEREx data. The SPHEREx team
convened a community workshop in February 2016, with the intent of enlisting
the aid of a larger group of scientists in defining these questions. This paper
summarizes the rich and varied menu of investigations that was laid out. It
includes studies of the composition of main belt and Trojan/Greek asteroids;
mapping the zodiacal light with unprecedented spatial and spectral resolution;
identifying and studying very low-metallicity stars; improving stellar
parameters in order to better characterize transiting exoplanets; studying
aliphatic and aromatic carbon-bearing molecules in the interstellar medium;
mapping star formation rates in nearby galaxies; determining the redshift of
clusters of galaxies; identifying high redshift quasars over the full sky; and
providing a NIR spectrum for most eROSITA X-ray sources. All of these
investigations, and others not listed here, can be carried out with the nominal
all-sky spectra to be produced by SPHEREx. In addition, the workshop defined
enhanced data products and user tools which would facilitate some of these
scientific studies. Finally, the workshop noted the high degrees of synergy
between SPHEREx and a number of other current or forthcoming programs,
including JWST, WFIRST, Euclid, GAIA, K2/Kepler, TESS, eROSITA and LSST.Comment: Report of the First SPHEREx Community Workshop,
http://spherex.caltech.edu/Workshop.html , 84 pages, 28 figure
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