Coupling Poisson and Jacobi structures on foliated manifolds

Let M be a differentiable manifold endowed with a foliation F. A Poisson structure P on M is F-coupling if the image of the annihilator of TF by the sharp-morphism defined by P is a normal bundle of the foliation F. This notion extends Sternberg's coupling symplectic form of a particle in a Yang-Mills field. In the present paper we extend Vorobiev's theory of coupling Poisson structures from fiber bundles to foliations and give simpler proofs of Vorobiev's existence and equivalence theorems of coupling Poisson structures on duals of kernels of transitive Lie algebroids over symplectic manifolds. Then we discuss the extension of the coupling condition to Jacobi structures on foliated manifolds.Comment: LateX, 38 page

Illuminating cell signaling with genetically encoded FRET biosensors in adult mouse cardiomyocytes.

FRET-based biosensor experiments in adult cardiomyocytes are a powerful way of dissecting the spatiotemporal dynamics of the complicated signaling networks that regulate cardiac health and disease. However, although much information has been gleaned from FRET studies on cardiomyocytes from larger species, experiments on adult cardiomyocytes from mice have been difficult at best. Thus the large variety of genetic mouse models cannot be easily used for this type of study. Here we develop cell culture conditions for adult mouse cardiomyocytes that permit robust expression of adenoviral FRET biosensors and reproducible FRET experimentation. We find that addition of 6.25 µM blebbistatin or 20 µM (S)-nitro-blebbistatin to a minimal essential medium containing 10 mM HEPES and 0.2% BSA maintains morphology of cardiomyocytes from physiological, pathological, and transgenic mouse models for up to 50 h after adenoviral infection. This provides a 10-15-h time window to perform reproducible FRET readings using a variety of CFP/YFP sensors between 30 and 50 h postinfection. The culture is applicable to cardiomyocytes isolated from transgenic mouse models as well as models with cardiac diseases. Therefore, this study helps scientists to disentangle complicated signaling networks important in health and disease of cardiomyocytes

Spontaneous Calcium Release in Cardiac Myocytes: Store Overload and Electrical Dynamics

Heart disease is the leading cause of mortality in the United States. One cause of heart arrhythmia is calcium (Ca2+) mishandling in cardiac muscle cells. We adapt Izu\u27s et al. mathematical reaction-diffusion model of calcium in cardiac muscle cells, or cardiomyocytes implemented by Gobbert, and analyzed in Coulibaly et al. to include calcium being released from the sarcoplasmic reticulum (SR), the effects of buffers in the SR, particularly calsequestrin, and the effects of Ca2+ influx due to voltage across the cell membrane. Based on simulations of the model implemented in parallel using MPI, our findings aligned with known biological models and principles, giving us a thorough understanding of several factors that influence Ca2+ dynamics in cardiac myocytes. Specifically, dynamic calcium store will cap previous calcium blow-up seen in the model. Calcium channels located in spatial opposition of calcium release units produce more predictable intracellular calcium propagation. And we used multi-parametric calcium dynamics tables, which act as a multidimensional bifurcation diagram, to visualize parameter boundaries between different biophysical dynamics

On the Selection of Pairing-Friendly Groups

We propose a simple algorithm to select group generators suitable for pairing-based cryptosystems. The selected parameters are shown to favor implementations of the Tate pairing that are at once conceptually simple and efficient, with an observed performance about 2 to 10 times better than previously reported implementations, depending on the embedding degree. Our algorithm has beneficial side effects: various non-pairing operations become faster, and bandwidth may be saved

Detection of Multi-TeV Gamma Rays from Markarian 501 during an Unforeseen Flaring State in 1997 with the Tibet Air Shower Array

In 1997, the BL Lac Object Mrk 501 entered a very active phase and was the brightest source in the sky at TeV energies, showing strong and frequent flaring. Using the data obtained with a high density air shower array that has been operating successfully at Yangbajing in Tibet since 1996, we searched for gamma-ray signals from this source during the period from February through August in 1997. Our observation detected multi-TeV $\gamma$-ray signals at the 3.7-Sigma level during this period. The most rapid increase of the excess counts was observed between April 7 and June 16 and the statistical significance of the excess counts in this period was 4.7-Sigma. Among several observations of flaring TeV gamma-rays from Mrk 501 in 1997, this is the only observation using a conventional air shower array. We present the energy spectrum of gamma-rays which will be worthy to compare with those obtained by imaging atmospheric Cerenkov telescopes.Comment: 9 pages, 7 figures, To appear in Ap

Observation of Multi-Tev Gamma Rays from the Crab Nebula Using the Tibet Air Shower Array

The Tibet experiment, operating at Yangbajing (4,300 m above sea level), is the lowest energy air shower array and the new high density array constructed in 1996 has sensitivity to $\gamma$-ray air showers at energies as low as 3 TeV. With this new array, the Crab Nebula was observed in multi-TeV $\gamma$-rays and a signal was detected at the 5.5 $\sigma$ level. We also obtained the energy spectrum of $\gamma$-rays in the energy region above 3 TeV which partially overlaps those observed with imaging atmospheric Cherenkov telescopes. This is the first observation of $\gamma$-ray signals from point sources with a conventional air shower array using scintillation detectors.Comment: 9 pages, 4 figures, Accepted for publication in ApJ Letter

Primary proton spectrum between 200 TeV and 1000 TeV observed with the Tibet burst detector and air shower array

Since 1996, a hybrid experiment consisting of the emulsion chamber and burst detector array and the Tibet-II air-shower array has been operated at Yangbajing (4300 m above sea level, 606 g/cm^2) in Tibet. This experiment can detect air-shower cores, called as burst events, accompanied by air showers in excess of about 100 TeV. We observed about 4300 burst events accompanied by air showers during 690 days of operation and selected 820 proton-induced events with its primary energy above 200 TeV using a neural network method. Using this data set, we obtained the energy spectrum of primary protons in the energy range from 200 to 1000 TeV. The differential energy spectrum obtained in this energy region can be fitted by a power law with the index of -2.97 $\pm$ 0.06, which is steeper than that obtained by direct measurements at lower energies. We also obtained the energy spectrum of helium nuclei at particle energies around 1000 TeV.Comment: 25 pages, 22 figures, Accepted for publication in Phys. Rev.

Empyema in children hospitalised at Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa: A retrospective study

Background. There is a paucity of information on empyema in children from low- and middle-income countries since the introduction of the pneumococcal conjugate vaccine.Objectives. To describe the aetiology and management of empyema in a setting of high HIV and tuberculosis (TB) prevalence.Methods. A retrospective descriptive study was undertaken between January 2012 and December 2016 in children aged <14 years at a large secondary-tertiary referral hospital in Soweto, South Africa. Cases of empyema were identified through administrative databases. Clinical, laboratory and radiological data were extracted from patient records.Results. We identified 65 cases of protocol-defined empyema, including 22 (33.8%) referred from surrounding hospitals. The median age at presentation was 53.2 months (interquartile range (IQR) 19.5 - 103.6). Thirteen patients (20.0%) were HIV-infected and 6 (9.2%) were HIV-exposed but uninfected. A bacterial pathogen was identified in 36 cases (55.3%). The commonest causative organisms were Staphylococcus aureus (14/65, 21.5%) and Streptococcus pneumoniae (5/65, 7.7%). Treatment for TB, initiated in 28 children (43.1%), was more frequent in HIV-infected children (10/13, 76.9%) (p=0.011); however, microbiological evidence of TB was present in only 5 cases (7.7%). Forty-three children (66.2%) had an intercostal drain (ICD) inserted and 16 (24.6%) a pigtail percutaneous catheter, while a fibrinolytic was only used in 6 (10.2%). Eight children (12.3%) had a thoracotomy and 7 (10.7%) had video-assisted thorascopic drainage, all of whom had a prior ICD inserted, a median of 20 days (IQR 10 - 33) before surgery. Overall, 7 children (10.8%) were mechanically ventilated and 1 (1.5%) died.Conclusions. Our study showed a dominance of S. aureus as a cause of empyema. A high proportion of HIV-infected children with empyema were initiated on TB treatment, highlighting challenges in managing TB-HIV co-infection. Although fibrinolytics or early surgery are recommended, neither practice was common in this setting.

Observation of Multi-Tev Diffuse Gamma Rays from the Galactic Plane with the Tibet Air Shower Array

Data from the Tibet-III air shower array (with energies around 3 TeV) and from the Tibet-II array (with energies around 10 TeV) have been searched for diffuse gamma rays from the Galactic plane. These arrays have an angular resolution of about 0.9 degrees. The sky regions searched are the inner Galaxy, 20 degrees <= l <= 55 degrees, and outer Galaxy, 140 degrees <= l <= 225 degrees, and |b| <= 2 degrees or <= 5 degrees. No significant Galactic plane gamma-ray excess was observed. The 99% confidence level upper limits for gamma-ray intensity obtained are (for |b| <= 2 degrees) 1.1 times 10^{-15} cm^{-2}s^{-1}sr^{-1}MeV^{-1} at 3 TeV and 4.1 times 10^{-17} cm^{-2}s^{-1}sr^{-1}MeV^{-1} at 10 TeV for the inner Galaxy, and 3.6 times 10^{-16} cm^{-2}s^{-1}sr^{-1}MeV^{-1} at 3 TeV and 1.3 times 10^{-17} cm^{-2}s^{-1}sr^{-1}MeV^{-1} at 10 TeV for the outer Galaxy, assuming a differential spectral index of 2.4. The upper limits are significant in the multi-TeV region when compared to those from Cherenkov telescopes in the lower energy region and other air shower arrays in the higher energy region; however, the results are not sufficient to rule out the inverse Compton model with a source electron spectral index of 2.0.Comment: 22 pages, 8 figures, Accepted for publication in Ap

Pirin is a prognostic marker of human melanoma that dampens the proliferation of malignant cells by downregulating JARID1B/KDM5B expression

Originally considered to act as a transcriptional co‑factor, Pirin has recently been reported to play a role in tumorigenesis and the malignant progression of many tumors. Here, we have analyzed the diagnostic and prognostic value of Pirin expression in the early stages of melanoma, and its role in the biology of melanocytic cells. Pirin expression was analyzed in a total of 314 melanoma biopsies, correlating this feature with the patient’s clinical course. Moreover, PIR downregulated primary melanocytes were analyzed by RNA sequencing, and the data obtained were validated in human melanoma cell lines overexpressing PIR by functional assays. The immunohistochemistry multivariate analysis revealed that early melanomas with stronger Pirin expression were more than twice as likely to develop metastases during the follow‑up. Transcriptome analysis of PIR downregulated melanocytes showed a dampening of genes involved in the G1/S transition, cell proliferation, and cell migration. In addition, an in silico approach predicted that JARID1B as a potential transcriptional regulator that lies between PIR and its downstream modulated genes, which was corroborated by co‑transfection experiments and functional analysis. Together, the data obtained indicated that Pirin could be a useful marker for the metastatic progression of melanoma and that it participates in the proliferation of melanoma cells by regulating the slow‑cycling JARID1B gene.This project was supported by grants from the Basque Government (KK2017-041 and KK2020-00069 to M.D.B.), the UPV/EHU (GIU17/066 to M.D.B.), H2020-ESCEL JTI (15/01 to M.D.B.) and MINECO (PCIN-2015-241 to M.D.B.). CP holds a predoctoral fellowship from the Basque Government. Part of this project is under European patent No. EP3051291 (EP14796149.4): “Method for diagnosis and prognosis of cutaneous melanoma”, Univer- sity of the Basque Country (UPV/EHU). The authors acknowledge the technical support SGIker resources at the UPV/EHU for the computational calculations, which were carried out in the Arina Informatics Cluster. The authors are grateful to the Basque Biobank for providing the biopsy samples and in particular, to María Jesús Fernández and Arantza Perez Dobaran for their technical support with the immunohistochemistry