A simple analytical alignment model for laser-kicked molecular rotors

We develop a mathematically simple yet accurate model for the single-pulse non-resonant impulsive alignment of thermal ensembles of linear molecules. We find that our molecular alignment model, which is based on the 2D rotor, not only provides a simplification for analytical and numerical calculations, but also establishes intuitive connections between system parameters, such as temperature and pulse intensity, and the resulting shape of the temporal molecular alignment

Chapter Refinement of Protein Tertiary Structure by Using Spin-Spin Coupling Constants from Nuclear Magnetic Resonance Measurements

Communications engineering / telecommunication

An ancient anterior patterning system promotes Caudal repression and head formation in Ecdysozoa.

SummaryPosterior expression of Caudal is required for early embryonic development in nematodes, arthropods, and vertebrates [1–9]. In Drosophila, ectopic Caudal in anterior cells can induce head defects, and in Caenorhabditis the absence of Caudal in anterior embryonic cells is required for proper development [6, 10]. Anterior Caudal repression in these species is achieved through unrelated translational repressors, the homeodomain protein Bicoid [11] and the KH domain factor Mex-3 [6, 12], respectively. Here we report that the Mex-3 ortholog in the flour beetle Tribolium plays a crucial role in head formation and that Caudal in this species is repressed by the combined activities of Mex-3 and Zen-2, a protein sharing common ancestry with the dipteran morphogen Bicoid. We propose that Mex-3 represents an ancient “anterior” promoting factor common to all Ecdysozoa (and maybe all Bilateria), whose role has been usurped in higher dipterans by Bicoid

Prediction and Generation of Binary Markov Processes: Can a Finite-State Fox Catch a Markov Mouse?

Understanding the generative mechanism of a natural system is a vital component of the scientific method. Here, we investigate one of the fundamental steps toward this goal by presenting the minimal generator of an arbitrary binary Markov process. This is a class of processes whose predictive model is well known. Surprisingly, the generative model requires three distinct topologies for different regions of parameter space. We show that a previously proposed generator for a particular set of binary Markov processes is, in fact, not minimal. Our results shed the first quantitative light on the relative (minimal) costs of prediction and generation. We find, for instance, that the difference between prediction and generation is maximized when the process is approximately independently, identically distributed.Comment: 12 pages, 12 figures; http://csc.ucdavis.edu/~cmg/compmech/pubs/gmc.ht

Blood lipid spectrum and elastic properties of arteries in patients with chronic pancreatitis in combination with arterial hypertension

110 patients aged 45-65 years with chronic pancreatitis were examined. The first group consisted of patients with a combined course of chronic pancreatitis with arterial hypertension; the second group - patients with chronic pancreatitis without concomitant hypertension. All patients were examined for total cholesterol, triglycerides, high-density lipoprotein cholesterol, lowdensity lipoprotein cholesterol, and very low-density lipoprotein cholesterol. Arterial stiffness was determined by the pulse wave velocity. It was found that patients of the 1st group had significantly higher levels of triglycerides (37.2%), low-density lipoprotein cholesterol (13%), total cholesterol (25%), atherogenic ratio (19.6%) and significantly lower levels of high-density lipoprotein cholesterol (15.4%). Correlations between age and the level of atherogenic ratio, lowdensity lipoprotein cholesterol were established – r=0.35; p<0.01; r=0.37; p<0.01, respectively. The duration of chronic pancreatitis positively correlated with the level of triglycerides, low-density lipoprotein cholesterol – r=0.43; p<0.01; r=0.34; p<0.01, respectively. The level of brachial artery augmentation index was significantly lower by 43% in patients with chronic pancreatitis in combination with arterial hypertension, while the aortic augmentation index was significantly higher by 37.6% (p<0.01). It was found that patients of the 1st group had a significantly higher pulse wave velocity in the carotid-femoral segment compared to the 2nd group – by 7.5% (p<0.01). Significant correlations have been established between the brachial artery augmentation index and age, total cholesterol, atherogenic ratio, high and low density lipoprotein cholesterol, triglycerides, cardiovascular risk level by the SCORE scale in patients with a combined course of chronic pancreatitis with arterial hypertension. Conclusions. Patients with the combination of chronic pancreatitis and hypertension had significantly higher levels of triglycerides, low-density lipoprotein cholesterol and total cholesterol. Changes in the elastic properties of arteries in patients with chronic pancreatitis with comorbid hypertension were characterized by an increase in the augmentation index and the pulse wave velocity in the carotid-femoral segme

The magnetic field along the jets of NGC 4258 as deduced from high frequency radio observations

We present 2.4" resolution, high sensitivity radio continuum observations of the nearby spiral galaxy NGC 4258 in total intensity and linear polarization obtained with the Very Large Array at 3.6 cm (8.44 GHz). The radio emission along the northern jet and the center of the galaxy is polarized and allows investigation of the magnetic field. Assuming energy-equipartition between the magnetic field and the relativistic particles and distinguishing between (1) a relativistic electron-proton jet and (2) a relativistic electron-positron jet, we obtain average magnetic field strengths of about (1) 310\muG and (2) 90\muG. The rotation measure is determined to range from -400 to -800 rad/m^2 in the northern jet. Correcting the observed E-vectors of polarized intensity for Faraday rotation, the magnetic field along the jet turns out to be orientated mainly along the jet axis. An observed tilt with respect to the jet axis may indicate also a toroidal magnetic field component or a slightly helical magnetic field around the northern jet.Comment: 9 pages with 9 figures. Accepted for publication in A&

Global Survey on Pancreatic Surgery During the COVID-19 Pandemic.

OBJECTIVE:The aim of this study was to clarify the role of pancreatic surgery during the COVID-19 pandemic to optimize patients\u27 and clinicians\u27 safety and safeguard health care capacity. SUMMARY BACKGROUND DATA:The COVID-19 pandemic heavily impacts health care systems worldwide. Cancer patients appear to have an increased risk for adverse events when infected by COVID-19, but the inability to receive oncological care seems may be an even larger threat, particularly in case of pancreatic cancer. METHODS:An online survey was submitted to all members of seven international pancreatic associations and study groups, investigating the impact of the COVID-19 pandemic on pancreatic surgery using 21 statements (April, 2020). Consensus was defined as \u3e80% agreement among respondents and moderate agreement as 60% to 80% agreement. RESULTS:A total of 337 respondents from 267 centers and 37 countries spanning 5 continents completed the survey. Most respondents were surgeons (n = 302, 89.6%) and working in an academic center (n = 286, 84.9%). The majority of centers (n = 166, 62.2%) performed less pancreatic surgery because of the COVID-19 pandemic, reducing the weekly pancreatic resection rate from 3 [interquartile range (IQR) 2-5] to 1 (IQR 0-2) (P \u3c 0.001). Most centers screened for COVID-19 before pancreatic surgery (n = 233, 87.3%). Consensus was reached on 13 statements and 5 statements achieved moderate agreement. CONCLUSIONS:This global survey elucidates the role of pancreatic surgery during the COVID-19 pandemic, regarding patient selection for the surgical and oncological treatment of pancreatic diseases to support clinical decision-making and creating a starting point for further discussion