Correlated decay of triplet excitations in the Shastry-Sutherland compound SrCu2_2(BO3_3)2_2

The temperature dependence of the gapped triplet excitations (triplons) in the 2D Shastry-Sutherland quantum magnet SrCu$_2$(BO$_3$)$_2$ is studied by means of inelastic neutron scattering. The excitation amplitude rapidly decreases as a function of temperature while the integrated spectral weight can be explained by an isolated dimer model up to 10~K. Analyzing this anomalous spectral line-shape in terms of damped harmonic oscillators shows that the observed damping is due to a two-component process: one component remains sharp and resolution limited while the second broadens. We explain the underlying mechanism through a simple yet quantitatively accurate model of correlated decay of triplons: an excited triplon is long-lived if no thermally populated triplons are near-by but decays quickly if there are. The phenomenon is a direct consequence of frustration induced triplon localization in the Shastry--Sutherland lattice.Comment: 5 pages, 4 figure

On Fields with Finite Information Density

The existence of a natural ultraviolet cutoff at the Planck scale is widely expected. In a previous Letter, it has been proposed to model this cutoff as an information density bound by utilizing suitably generalized methods from the mathematical theory of communication. Here, we prove the mathematical conjectures that were made in this Letter.Comment: 31 pages, to appear in Phys.Rev.

A study of the gravitational wave form from pulsars II

We present analytical and numerical studies of the Fourier transform (FT) of the gravitational wave (GW) signal from a pulsar, taking into account the rotation and orbital motion of the Earth. We also briefly discuss the Zak-Gelfand Integral Transform. The Zak-Gelfand Integral Transform that arises in our analytic approach has also been useful for Schrodinger operators in periodic potentials in condensed matter physics (Bloch wave functions).Comment: 6 pages, Sparkler talk given at the Amaldi Conference on Gravitational waves, July 10th, 2001. Submitted to Classical and Quantum Gravit

A Monitoring System for Crimean Congo Hemorrhagic Fever Epidemiology Studies in Afghanistan

In the last few years, tick-borne diseases have been reported as a resurging in the Middle East. Crimean-Congo hemorrhagic fever (CCHF) is endemic in the Middle East, including Turkey, Iran, Afghanistan and Pakistan. Recent studies have explored the causal link between environmental and disease incidence patterns by correlating remote sensing indicators (surface temperature, rainfall, and vegetation indices of plant photosynthetic activity) with spatially explicit epidemiological data. We combined the monitoring of environmental data at monthly temporal resolutions with available reports of confirmed CCHF cases to identify the environmental properties of endemic regions and quantify those properties to CCHF risk. We also conducted a sero-prevalence survey in a sample of households (human and animal specimens) in 9 villages in Engil district surrounding Herat province, in western Afghanistan. We present analysis results from our study villages and validate the associated environmental conditions as predictive for human disease occurrences. Risk prediction is critical for anticipating the type and potential impact of disease threats for timely response action

Exploiting macrophage autophagy-lysosomal biogenesis as a therapy for atherosclerosis

Macrophages specialize in removing lipids and debris present in the atherosclerotic plaque. However, plaque progression renders macrophages unable to degrade exogenous atherogenic material and endogenous cargo including dysfunctional proteins and organelles. Here we show that a decline in the autophagy-lysosome system contributes to this as evidenced by a derangement in key autophagy markers in both mouse and human atherosclerotic plaques. By augmenting macrophage TFEB, the master transcriptional regulator of autophagy-lysosomal biogenesis, we can reverse the autophagy dysfunction of plaques, enhance aggrephagy of p62-enriched protein aggregates and blunt macrophage apoptosis and pro-inflammatory IL-1β levels, leading to reduced atherosclerosis. In order to harness this degradative response therapeutically, we also describe a natural sugar called trehalose as an inducer of macrophage autophagy-lysosomal biogenesis and show trehalose's ability to recapitulate the atheroprotective properties of macrophage TFEB overexpression. Our data support this practical method of enhancing the degradative capacity of macrophages as a therapy for atherosclerotic vascular disease

Cognitive appraisal of environmental stimuli induces emotion-like states in fish

The occurrence of emotions in non-human animals has been the focus of debate over the years. Recently, an interest in expanding this debate to non-tetrapod vertebrates and to invertebrates has emerged. Within vertebrates, the study of emotion in teleosts is particularly interesting since they represent a divergent evolutionary radiation from that of tetrapods, and thus they provide an insight into the evolution of the biological mechanisms of emotion. We report that Sea Bream exposed to stimuli that vary according to valence (positive, negative) and salience (predictable, unpredictable) exhibit different behavioural, physiological and neuromolecular states. Since according to the dimensional theory of emotion valence and salience define a two-dimensional affective space, our data can be interpreted as evidence for the occurrence of distinctive affective states in fish corresponding to each the four quadrants of the core affective space. Moreover, the fact that the same stimuli presented in a predictable vs. unpredictable way elicited different behavioural, physiological and neuromolecular states, suggests that stimulus appraisal by the individual, rather than an intrinsic characteristic of the stimulus, has triggered the observed responses. Therefore, our data supports the occurrence of emotion-like states in fish that are regulated by the individual's perception of environmental stimuli.European Commission [265957 Copewell]; Fundacao para a Ciencia e Tecnologia [SFRH/BD/80029/2011, SFRH/BPD/72952/2010]info:eu-repo/semantics/publishedVersio

Integrating transposable elements in the 3D genome

Chromosome organisation is increasingly recognised as an essential component of genome regulation, cell fate and cell health. Within the realm of transposable elements (TEs) however, the spatial information of how genomes are folded is still only rarely integrated in experimental studies or accounted for in modelling. Whilst polymer physics is recognised as an important tool to understand the mechanisms of genome folding, in this commentary we discuss its potential applicability to aspects of TE biology. Based on recent works on the relationship between genome organisation and TE integration, we argue that existing polymer models may be extended to create a predictive framework for the study of TE integration patterns. We suggest that these models may offer orthogonal and generic insights into the integration profiles (or "topography") of TEs across organisms. In addition, we provide simple polymer physics arguments and preliminary molecular dynamics simulations of TEs inserting into heterogeneously flexible polymers. By considering this simple model, we show how polymer folding and local flexibility may generically affect TE integration patterns. The preliminary discussion reported in this commentary is aimed to lay the foundations for a large-scale analysis of TE integration dynamics and topography as a function of the three-dimensional host genome

Correlation of CDX2 Protein Expression with Clinicopathologic Features and Survival Rate in Iraqi Patients with Colorectal Cancer

Predicting the prognosis of colorectal cancer (CRC) is challenging since these tumors exhibit a wide range of biological behaviors. It has been hypothesized that caudal-related homeobox gene 2 (CDX2), which is vital for intestinal growth and maintenance, has a tumor-suppressing effect and promising role in CRC prognosis but studies are still controversial. This study used the immunohistochemical (IHC) staining method to determine the expression of the CDX2 protein in mucinous and non-mucinous CRC adenocarcinoma, as well as in normal colorectal tissues as a control, and correlate this expression with clinicopathological features such as grade, tumor distant metastasis, tumor site, histological type, lymph node metastasis, tumor invasion, sex, age, and rate of 4 years Overall survival (OS) after diagnosis. A total of sixty three tissue samples were obtained from CRC patients (58.90±14.94) years and embedded in wax and thirty-seven normal non-tumoural colorectal tissue samples with (56.43±12.28) years as a control group. CDX2 protein expression decreased significantly (p<0.05) in CRC patients than control, advanced age, mucinous pattern of CRC, moderate and poorly differentiated grades, lymph node metastasis, advanced tumor invasion (T3, T4), and organs metastasis. Moreover, the (OS) for patients with low CDX2 expression was (17.943±1.7) months compared to (33.431±2.7) months for those with high CDX2 expression (p = 0.0001). This study concluded that protein expression of CDX2 is regarded as a prognostic and diagnostic marker for CRC patients