Bias and consistency in time delay estimation methods: case of the double quasar HE 1104-1805

We present a short re-evaluation of a recently published time delay estimate for the gravitational lens system HE 1104-1805 with emphasis on important methodological aspects: bias of the statistics, inconsistency of the methods and use of the purposeful selection of data points(or so-called "cleaning") at the preprocessing stage. We show how the inadequate use of simple analysis methods can lead to too strong conclusions. Our analysis shows that there are indications for the time delay in HE 1104-1805 to be between -0.9 and -0.7 years, but still with a large uncertainty.Comment: 5 pages, 5 figures, accepted as a Letter to the Editor in A&

Stochastic Continuous Time Neurite Branching Models with Tree and Segment Dependent Rates

In this paper we introduce a continuous time stochastic neurite branching model closely related to the discrete time stochastic BES-model. The discrete time BES-model is underlying current attempts to simulate cortical development, but is difficult to analyze. The new continuous time formulation facilitates analytical treatment thus allowing us to examine the structure of the model more closely. We derive explicit expressions for the time dependent probabilities p(\gamma, t) for finding a tree \gamma at time t, valid for arbitrary continuous time branching models with tree and segment dependent branching rates. We show, for the specific case of the continuous time BES-model, that as expected from our model formulation, the sums needed to evaluate expectation values of functions of the terminal segment number \mu(f(n),t) do not depend on the distribution of the total branching probability over the terminal segments. In addition, we derive a system of differential equations for the probabilities p(n,t) of finding n terminal segments at time t. For the continuous BES-model, this system of differential equations gives direct numerical access to functions only depending on the number of terminal segments, and we use this to evaluate the development of the mean and standard deviation of the number of terminal segments at a time t. For comparison we discuss two cases where mean and variance of the number of terminal segments are exactly solvable. Then we discuss the numerical evaluation of the S-dependence of the solutions for the continuous time BES-model. The numerical results show clearly that higher S values, i.e. values such that more proximal terminal segments have higher branching rates than more distal terminal segments, lead to more symmetrical trees as measured by three tree symmetry indicators.Comment: 41 pages, 2 figures, revised structure and text improvement

Insect species described from Big Bend National Park

The list contains 192 insect species, of which 139 are primary types. All have been described from material collected in or near Big Bend National Park, Texas

1st INCF Workshop on Global Portal Services for Neuroscience

The goal of this meeting was to map out existing portal services for neuroscience, identify their features and future plans, and outline opportunities for synergistic developments. The workshop discussed alternative formats of future global and integrated portal services

Cases of Lyme Disease Appear to Follow Periodic Cycles Linked to Geography

We are studying the spread of Lyme disease through Wisconsin. It is important because the number of people diagnosed with Lyme Disease in the US is around 300,000, annually (CDC 2017). The CDC has collected data of reported Lyme Disease cases since 2001. When looking at the data we noticed that the trends of cases of Lyme disease followed a cyclical pattern. The cycles varied widely. We hypothesized that environmental and geographical factors could affect the main vector of Lyme Disease, Ixodes scapularis (the black-legged tick). After analyzing Lyme Disease data from the CDC and using a map making software (Paint Maps 2018), we found that geographical distribution had a marked effect on the rate at which counties cycled between up and down trends in infection rates. These findings are important because they give us more insight into possible control methods to keep the black-legged tick, and therefore Lyme Disease, at a manageable level

San Francisco Bay: Preparing for the next level

This report provides new insights on the impacts climate change poses on San Francisco Bay, the opportunities this challenge brings and some potential guidelines on how to move forward, as the Bay Area continues to position itself in leading the way nationally and internationally on climate change adaptation. This report is also a landmark in the cooperation between the Netherlands and California on climate change adaptation. A team of professionals from both sides of the ocean has worked on this projec

1st INCF Workshop on Sustainability of Neuroscience Databases

The goal of the workshop was to discuss issues related to the sustainability of neuroscience databases, identify problems and propose solutions, and formulate recommendations to the INCF. The report summarizes the discussions of invited participants from the neuroinformatics community as well as from other disciplines where sustainability issues have already been approached. The recommendations for the INCF involve rating, ranking, and supporting database sustainability

Century scale persistence in longitude distribution: in the Sun and in silico

Using Greenwich sunspot data for 120 years it was recently observed that activity regions on the Sun's surface tend to lie along smoothly changing longitude strips 180 degrees apart from each other. However, numerical experiments with random input data show that most, if not all, of the observed longitude discrimination can be looked upon as an artifact of the analysis method.Comment: 4 pages, 12 figures, accepted for publication in Astronomy and Astrophysic