The Entropy Principle and the Influence of Sociological Pressures on SETI

We begin with the premise that the law of entropy could prove to be fundamental for the evolution of intelligent life and the advent of technological civilization. Building on recent theoretical results, we combine a modern approach to evolutionary theory with Monte Carlo Realization Techniques. A numerical test for a proposed significance of the law of entropy within the evolution of intelligent species is performed and results are compared with a neutral test hypothesis. Some clarifying aspects on the emergence of intelligent species arise and are discussed in the framework of contemporary astrobiology.Comment: 11 pages, 5 figures, accepted for publication in the International Journal of Astrobiolog

Numerical Testing of The Rare Earth Hypothesis using Monte Carlo Realisation Techniques

The Search for Extraterrestrial Intelligence (SETI) has thus far failed to provide a convincing detection of intelligent life. In the wake of this null signal, many "contact pessimistic" hypotheses have been formulated, the most famous of which is the Rare Earth Hypothesis. It postulates that although terrestrial planets may be common, the exact environmental conditions that Earth enjoys are rare, perhaps unique. As a result, simple microbial life may be common, but complex metazoans (and hence intelligence) will be rare. This paper uses Monte Carlo Realisation Techniques to investigate the Rare Earth Hypothesis, in particular the environmental criteria considered imperative to the existence of intelligence on Earth. By comparing with a less restrictive, more optimistic hypothesis, the data indicates that if the Rare Earth hypothesis is correct, intelligent civilisation will indeed be relatively rare. Studying the separations of pairs of civilisations shows that most intelligent civilisation pairs (ICPs) are unconnected: that is, they will not be able to exchange signals at lightspeed in the limited time that both are extant. However, the few ICPs that are connected are strongly connected, being able to participate in numerous exchanges of signals. This may provide encouragement for SETI researchers: although the Rare Earth Hypothesis is in general a contact-pessimistic hypothesis, it may be a "soft" or "exclusive" hypothesis, i.e. it may contain facets that are latently contact-optimistic.Comment: 13 pages, 10 figures, accepted for publication in the International Journal of Astrobiolog

Lensing reconstruction from Planck sky maps: inhomogeneous noise

We discuss the effects of inhomogeneous sky coverage on cosmic microwave background lens reconstruction, focusing on application to the recently launched Planck satellite. We discuss the 'mean field' which is induced by noise inhomogeneities, as well as three approaches to lens reconstruction in this context: an optimal maximum-likelihood approach which is computationally expensive to evaluate and two suboptimal approaches which are less intensive. The first of these is only suboptimal at the 5 per cent level for Planck, and the second prevents biasing due to uncertainties in the noise model

New μ\mu Forces From νμ\nu_\mu Sources

Accelerator-based experiments reliant on charged pion and kaon decays to produce muon-neutrino beams also deliver an associated powerful flux of muons. Therefore, these experiments can additionally be sensitive to light new particles that preferentially couple to muons and decay to visible final states on macroscopic length scales. Such particles are produced through rare 3-body meson decays in the decay pipe or via muon scattering in the beam dump, and decay in a downstream detector. To demonstrate the potential of this search strategy, we recast existing MiniBooNE and MicroBooNE studies of neutral pion production in neutrino-induced neutral-current scattering ($\nu_\mu N \to \nu_\mu N \pi^0,~\pi^0\rightarrow \gamma\gamma$) to place new leading limits on light ($< 2m_\mu$) muon-philic scalar particles that decay to diphotons through loops of virtual muons. Our results exclude scalars of mass between 10 and 60 MeV in which this scenario resolves the muon $g-2$ anomaly. We also make projections for the sensitivity of SBND to these models and provide a road map for future neutrino experiments to perform dedicated searches for muon-philic forces.Comment: 6 pages, 6 figure

Quantitative adsorbate structure determination under catalytic reaction conditions

Current methods allow quantitative local structure determination of adsorbate geometries on surfaces in ultrahigh vacuum (UHV) but are incompatible with the higher pressures required for a steady-state catalytic reactions. Here we show that photoelectron diffraction can be used to determine the structure of the methoxy and formate reaction intermediates during the steady-state oxidation of methanol over Cu(110) by taking advantage of recent instrumental developments to allow near-ambient pressure x-ray photoelectron spectroscopy. The local methoxy site differs from that under static UHV conditions, attributed to the increased surface mobility and dynamic nature of the surface under reaction conditions

Lighting up the LHC with Dark Matter

We show that simultaneously explaining dark matter and the observed value of the muon's magnetic dipole moment may lead to yet unexplored photon signals at the LHC. We consider the Minimal Supersymmetric Standard Model with electroweakino masses in the few-to-several hundred GeV range, and opposite sign of the Bino mass parameter with respect to both the Higgsino and Wino mass parameters. In such region of parameter space, the spin-independent elastic scattering cross section of a Bino-like dark matter candidate in direct detection experiment is suppressed by cancellations between different amplitudes, and the observed dark matter relic density can be realized via Bino-Wino co-annihilation. Moreover, the observed value of the muon's magnetic dipole moment can be explained by Bino and Wino loop contributions. Interestingly, "radiative" decays of Wino-like neutralinos into the lightest neutralino and a photon are enhanced, whereas decays into leptons are suppressed. While these decay patterns weaken the reach of multi-lepton searches at the LHC, the radiative decay opens a new window for probing dark matter at the LHC through the exploration of parameter space regions beyond those currently accessible. To complement the current electroweakino searches, we propose searching for a single (soft) photon plus missing transverse energy, accompanied by a hard initial state radiation jet

CMBPol Mission Concept Study: Gravitational Lensing

Gravitational lensing of the cosmic microwave background by large-scale structure in the late universe is both a source of cosmological information and a potential contaminant of primordial gravity waves. Because lensing imprints growth of structure in the late universe on the CMB, measurements of CMB lensing will constrain parameters to which the CMB would not otherwise be sensitive, such as neutrino mass. If the instrumental noise is sufficiently small (<~ 5 uK-arcmin), the gravitational lensing contribution to the large-scale B-mode will be the limiting source of contamination when constraining a stochastic background of gravity waves in the early universe, one of the most exciting prospects for future CMB polarization experiments. High-sensitivity measurements of small-scale B-modes can reduce this contamination through a lens reconstruction technique that separates the lensing and primordial contributions to the B-mode on large scales. A fundamental design decision for a future CMB polarization experiment such as CMBpol is whether to have coarse angular resolution so that only the large-scale B-mode (and the large-scale E-mode from reionization) is measured, or high resolution to additionally measure CMB lensing. The purpose of this white paper is to evaluate the science case for CMB lensing in polarization: constraints on cosmological parameters, increased sensitivity to the gravity wave B-mode via lens reconstruction, expected level of contamination from non-CMB foregrounds, and required control of beam systematics

Association between body mass index, physical activity and motor competence in children: Moderation analysis by different environmental contexts

Background Although the association between body mass index (BMI), physical activity (PA) and motor competence (MC) has been widely investigated, the influence of different environmental contexts is not well defined. Aim To analyse the relationship between BMI, PA and MC and the moderating role of the environmental context. Subjects and methods A cross-sectional study was performed with 668 children (318 boys) aged 5–7 years (north-eastern district – Brazil). MC (Körper koordination test fur Kinder; KTK), BMI and PA (parent reporting) were assessed. To classify three contexts of the environment a variable was created based on the presence of a sports court in school and/or environment for play or sports practice out of school. Multilevel mixed-effects linear regressions, interaction test and estimation of coefficients in moderation analysis were used. Results BMI (β = −2.93; p < .01) and age (β = 19.02; p < .01) were associated, and PA was not associated (β = 0.07; p = .05) with MC. The strength of the association between BMI and MC changed based on the environmental contexts. The better the environment context the weaker the association between BMI and MC (β = −2.93, p < .01 to β = −2.38, p = .33 to β = 0.26, p = .94). Conclusions The association between BMI and MC is moderated by environmental contexts

Chromospheric activity as age indicator

Chromospheric activity has been calibrated and widely used as an age indicator. However, it has been suggested that the viability of this age indicator is, in the best case, limited to stars younger than about 1.5 Gyr. I aim to define the age range for which chromospheric activity is a robust astrophysical clock. I collected literature measurements of the S-index in field stars, which is a measure of the strength of the H and K lines of the Ca II and a proxy for chromospheric activity, and exploited the homogeneous database of temperature and age determinations for field stars provided by the Geneva-Copenhagen survey of the solar neighbourhood. Field data, inclusive data previously used to calibrate chromospheric ages, confirm the result found using open cluster data, i.e. there is no decay of chromospheric activity after about 2 Gyr. The only existing indication supporting the viability of chromospheric ages older than 2 Gyr is the similarity of chromospheric activity levels in the components of 35 dwarf binaries. However, even in the most optimistic scenario, uncertainty in age determination for field stars and lack of sufficient data in open clusters make any attempt of calibrating an age activity relationship for old stars premature. The hypothesis that chromospheric activity follows the Skumanich law, i.e. that it is proportional to the inverse square root of the age, should be relaxed.Comment: 5 pages, 2 figures, A&A letters, accepte

DATA MINING IN ORGANIC GEOCHEMISTRY: CASE STUDY IN POTIGUAR BASIN: Mineração de dados na Geoquímica Orgânica: estudo de caso na Bacia Potiguar

The amount of data from geochemical analysis using samples collected in oil wells grows simultaneously to the investment in the exploration and production sector. On the other hand, the treatment and interpretation of these results are still very dependent on experts and demand time. With the generation of extensive databases, data mining presents itself as a good alternative to explore them through statistical methods and computational algorithms, providing technological differential and agility to the system. In an experimental way, with data from 200 oils from the Potiguar Basin, these tools were implemented, with the consequent suggestion of a workflow that would, in the end, return a reasonable accuracy in predicting their genetic classification. Using multidimensional scaling (MDS) and clustering (dendrogram and k-means types) from 60 initial attributes, the optimal set was reduced to 26. Applying Machine Learning, 92.50% of median accuracy were obtained in the Decision Tree algorithm, 95.00% in Random Forest and 87.50% in Artificial Neural Network. Comparing to an analysis previously presented at the pertinent literature, the benefits in terms of efficiency can be realized with the adoption of the methodology herein proposed. &nbsp; Keywords: Organic geochemistry; Data Mining; Multivariate Statistics; Workflow.A quantidade de dados provenientes de análises geoquímicas de amostras coletadas em poços de petróleo cresce simultaneamente ao investimento no setor de exploração e produção. Por outro lado, o tratamento e a interpretação desses resultados ainda é muito dependente de especialistas, e demanda tempo. Com a geração de extensas bases de dados, a mineração de dados se apresenta como uma boa alternativa para explorá-los por meio de métodos estatísticos e computacionais, proporcionando diferencial tecnológico e agilidade ao sistema. De forma experimental, com dados de 200 óleos da Bacia Potiguar, essas ferramentas foram implementadas, com a consequente sugestão de um fluxo de trabalho que, ao final, pôde retornar uma precisão razoável na previsão da classificação genética das amostras. Usando escalonamento multidimensional (MDS) e agrupamentos (dos tipos dendrograma e k-means) de 60 atributos iniciais, o conjunto ideal foi reduzido para 26. Aplicando aprendizado de máquinas, 92,50% de acurácia mediana foram obtidos no algoritmo de Árvore de Decisão, 95,00% na Floresta Aleatória e 87,50% em Rede Neural Artificial. Comparando a uma análise previamente apresentada na literatura pertinente, os benefícios em termos de eficiência podem ser percebidos com a adoção da metodologia aqui proposta. &nbsp; Palavras-chave: Geoquímica Orgânica; Mineração de dados; Estatística multivariada; Fluxo de Trabalho