The velocity field of baryonic gas in the universe

The dynamic evolution of the baryonic intergalactic medium (IGM) caused by the underlying dark matter gravity is governed by the Navier-Stokes equations in which many cooling and heating processes are involved. However, it has long been recognized that the growth mode dynamics of cosmic matter clustering can be sketched by a random force driven Burgers' equation if cooling and heating are ignored. Just how well the dynamics of the IGM can be described as a Burgers fluid has not been fully investigated probably because cooling and heating are essential for a detailed understanding of the IGM. Using IGM samples produced by a cosmological hydrodynamic simulation in which heating and cooling processes are properly accounted for, we show that the IGM velocity field in the nonlinear regime shows the features of a Burgers fluid, that is, when the Reynolds number is high, the velocity field consists of an ensemble of shocks. Consequently, (1) the IGM velocity $v$ is generally smaller than that of dark matter; (2) for the smoothed field, the IGM velocity shows tight correlation with dark matter given by $v \simeq s v_{dm}$, with $s<1$, such that the lower the redshift, the smaller $s$; (3) the velocity PDFs are asymmetric between acceleration and deceleration events; (4) the PDF of velocity difference $\Delta v=v(x+r)-v(x)$ satisfies the scaling relation for a Burgers fluid, i.e., $P(\Delta v)=(1 r^y)F(\Delta v/r^y)$. We find the scaling function and parameters for the IGM which are applicable to the entire scale range of the samples (0.26 - 8 h$^{-1}$ Mpc). These properties show that the similarity mapping between the IGM and dark matter is violated on scales much larger than the Jeans length of the IGM.Comment: 14 pages, 10 jpg-figures, accepted for publication in the Astrophysical Journal. References adde

Analyzing Gerrit Code Review Parameters with Bicho

Code review is becoming a common practice in large scale software development projects. In the case of free, open source software projects, many of them are selecting Gerrit as the system to support the code review process. Therefore, the analysis of the information produced by Gerrit allows for the detailed tracking of the code review process in those projects. In this paper, we present an approach to retrieve and analyze that information based on extending Bicho, a tool designed to retrieve information from issue tracking systems. The details of the retrieval process, the model used to map code review abstractions to issue tracking abstractions, and the structure of the retrieved information are described in detail. In addition, some results of using this approach in a real world scenario, the OpenStack Gerrit code review system, are presented

Synthetic multistability in mammalian cells

In multicellular organisms, gene regulatory circuits generate thousands of molecularly distinct, mitotically heritable states, through the property of multistability. Designing synthetic multistable circuits would provide insight into natural cell fate control circuit architectures and allow engineering of multicellular programs that require interactions among cells in distinct states. Here we introduce MultiFate, a naturally-inspired, synthetic circuit that supports long-term, controllable, and expandable multistability in mammalian cells. MultiFate uses engineered zinc finger transcription factors that transcriptionally self-activate as homodimers and mutually inhibit one another through heterodimerization. Using model-based design, we engineered MultiFate circuits that generate up to seven states, each stable for at least 18 days. MultiFate permits controlled state-switching and modulation of state stability through external inputs, and can be easily expanded with additional transcription factors. Together, these results provide a foundation for engineering multicellular behaviors in mammalian cells

The Effect of Cr Concentration on Defect Energies in FeCr Alloys

FeCr ferritic alloys are leading candidates for structural applications in generation IV fission reactors due to their high resistance to swelling and corrosion. The addition of Cr improves the behavior of the steels under irradiation, but this improvement is non-monotonic. Understandig the changes in the FeCr ferritic alloys microstructure induced by irradiation and the role played by the alloying element (Cr) is needed in order to predict the response of these materials under the extreme conditions in the future nuclear plants. In this work, we present the effect of Cr concentration in a bcc Fe matrix on binding and formation energies of vacancy clusters

Teleoperación de Instrumentos Quirúrgicos Articulados

En este trabajo se describe la plataforma CISOBOT, desarrollada por la Universidad de Málaga para intervenciones de cirugía mínimamente invasiva, así como su ampliación a través del diseño mecatrónico de un instrumento motorizado que permite mover el extremo de este. El objetivo de esta plataforma es el estudio de nuevos algoritmos de control que permitan la teleoperación bilateral y el empleo de guiado hápticoUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

FEPDS: A Proposal for the Extraction of Fuzzy Emerging Patterns in Data Streams

Nowadays, most data is generated by devices that produce data continuously. These kinds of data can be categorised as data streams and valuable insights can be extracted from them. In particular, the insights extracted by emerging patterns are interesting in a data stream context as easy, fast, reliable decisions can be made. However, their extraction is a challenge due to the necessary response time, memory and continuous model updates. In this paper, an approach for the extraction of emerging patterns in data streams is presented. It processes the instances by means of batches following an adaptive approach. The learning algorithm is an evolutionary fuzzy system where previous knowledge is employed in order to adapt to concept drift. A wide experimental study has been performed in order to show both the suitability of the approach in combating concept drift and the quality of the knowledge extracted. Finally, the proposal is applied to a case study related to the continuous determination of the profiles of New York City cab customers according to their fare amount, in order to show its potential

Factors Associated with the Risk of Falls of Nursing Home Residents Aged 80 or Older

Background: Falls are the leading cause of mortality and morbidity in older and represents one of the major and most costly public health problems worldwide. Purpose: Evaluate the influences of lower limb muscle performance, static balance, functional independence and quality of life on fall risk as assessed with the Timed Up and Go test. Design: Crosssectional. Methods: Fifty-two residents aged 80 or older were assessed and distributed in one of the two study groups according to the time to complete the Timed Up and Go Test. A Kistler force platform and linear transducer was used to determinate lower limb muscle performance. Postural Stability was measured by recording the center of pressure. The EuroQol-5 dimension was used to assess Health-Related Quality of Life and the Barthel Index was used to examine functional status. Student t-test was performed to evaluate the differences between groups. Correlations between variables were analyzed using Spearman or Pearson coefficient. ROC analysis was used to determine the cut-off points related to a decrease in the risk of a fall. Findings: Participants of no-fall risk group showed better lower limb performance, quality of life, and functional status. Cut-off points were determined for each outcome. Conclusions: Risk of falls in nursing home residents over the age of 80 is associated with lower limb muscle performance, functional status and quality of Life. Clinical Relevance: Cut-off points can be used by clinicians when working toward fall prevention and could help in determining the optimal lower limb muscle performance level for preventing falls