Pulses of darkness shift the phase of a circadian rhythm in an insectivorous bat

The circadian rhythm of a tropical insectivorous bat, Taphozous melanopogon, free-runs in dim light and responds to dark breaks of a few hours' duration with 'advances' and 'delays' as a function of the phase experiencing the "black out". Similarly phase shifts also follow perturbations by light breaks. The time course and the wave form of the phase response curves obtained from experiments using pulsed light and pulsed darkness are mirror images of each other

Chronobiotic effect of melatonin following phase shift of light/dark cycles in the field mouse Mus booduga

The objective of this study was to assess whether melatonin accelerates the re-entrainment of locomotor activity after 6 h of advance and delay phase shifts following exposure to LD 12:12 cycle (simulating jet-lag/shift work). An experimental group of adult male field mice Mus booduga were subjected to melatonin (1 mg/kg) through i.p. and the control group were treated with 50 % DMSO. The injections were administered on three consecutive days following 6h of phase advance and delay, at the expected time of "lights off". The results show that melatonin accelerates the re-entrainment after phase advance (29%) when compared with control mice. In the 6 h phase delay study, the experimental mice (melatonin administered) take more cycles for re-entrainment (51%) than the control. Further, the results suggest that though melatonin may be useful for the treatment of jet-lag caused by eastward flight (phase advance) it may not be useful for westward flight (phase delay) jet-lag

Discovering Object-Centric Generalized Value Functions From Pixels

Deep Reinforcement Learning has shown significant progress in extracting useful representations from high-dimensional inputs albeit using hand-crafted auxiliary tasks and pseudo rewards. Automatically learning such representations in an object-centric manner geared towards control and fast adaptation remains an open research problem. In this paper, we introduce a method that tries to discover meaningful features from objects, translating them to temporally coherent "question" functions and leveraging the subsequent learned general value functions for control. We compare our approach with state-of-the-art techniques alongside other ablations and show competitive performance in both stationary and non-stationary settings. Finally, we also investigate the discovered general value functions and through qualitative analysis show that the learned representations are not only interpretable but also, centered around objects that are invariant to changes across tasks facilitating fast adaptation.Comment: Accepted at ICML 202

Direct correlation between the circadian sleep-wakefulness rhythm and time estimation in humans under social and temporal isolation

Several bodily functions in humans vary on a 24 h pattern and most of these variations persist with a circadian period of ca 25 h when subjects are studied under conditions of social and temporal isolation. We report in this paper that the estimates of short time intervals (TE) of 2 h are strongly coupled to the circadian rhythm in sleepwakefulness. There is a linear correlation between the number of hours humans stay awake (α) and their estimation of 2 h intervals. The coupling of TE to α appears to obtain only under conditions of physical well-being

Annotation Studio: multimedia text annotation for students

Annotation Studio will be a web-based application that actively engages students in interpreting literary texts and other humanities documents. While strengthening students' new media literacies, this open source web application will develop traditional humanistic skills including close reading, textual analysis, persuasive writing, and critical thinking. Initial features will include: 1) easy-to-use annotation tools that facilitate linking and comparing primary texts with multi-media source, variation, and adaptation documents; 2) sharable collections of multimedia materials prepared by faculty and student users; 3) multiple filtering and display mechanisms for texts, written annotations, and multimedia annotations; 4) collaboration functionality; and 5) multimedia composition tools. Products of the start-up phase will include a working prototype, feedback from students and instructors, and a white paper summarizing lessons learned

Modelling of aortic aneurysm and aortic dissection through 3D printing

Introduction: The aim of this study was to assess if the complex anatomy of aortic aneurysm and aortic dissection can be accurately reproduced from a contrast-enhanced computed tomography (CT) scan into a three-dimensional (3D) printed model. Methods: Contrast-enhanced cardiac CT scans from two patients were post-processed and produced as 3D printed thoracic aorta models of aortic aneurysm and aortic dissection. The transverse diameter was measured at five anatomical landmarks for both models, compared across three stages: the original contrast-enhanced CT images, the stereolithography (STL) format computerised model prepared for 3D printing and the contrast-enhanced CT of the 3D printed model. For the model with aortic dissection, measurements of the true and false lumen were taken and compared at two points on the descending aorta. Results: Three-dimensional printed models were generated with strong and flexible plastic material with successful replication of anatomical details of aortic structures and pathologies. The mean difference in transverse vessel diameter between the contrast-enhanced CT images before and after 3D printing was 1.0 and 1.2 mm, for the first and second models respectively (standard deviation: 1.0 mm and 0.9 mm). Additionally, for the second model, the mean luminal diameter difference between the 3D printed model and CT images was 0.5 mm. Conclusion: Encouraging results were achieved with regards to reproducing 3D models depicting aortic aneurysm and aortic dissection. Variances in vessel diameter measurement outside a standard deviation of 1 mm tolerance indicate further work is required into the assessment and accuracy of 3D model reproduction. © 2017 Australian Society of Medical Imaging and Radiation Therapy and New Zealand Institute of Medical Radiation Technology

Circadian Rhythm Disruption Promotes Lung Tumorigenesis

Circadian rhythms are 24-hr oscillations that control a variety of biological processes in living systems, including two hallmarks of cancer, cell division and metabolism. Circadian rhythm disruption by shift work is associated with greater risk for cancer development and poor prognosis, suggesting a putative tumor-suppressive role for circadian rhythm homeostasis. Using a genetically engineered mouse model of lung adenocarcinoma, we have characterized the effects of circadian rhythm disruption on lung tumorigenesis. We demonstrate that both physiologic perturbation (jet lag) and genetic mutation of the central circadian clock components decreased survival and promoted lung tumor growth and progression. The core circadian genes Per2 and Bmal1 were shown to have cell-autonomous tumor-suppressive roles in transformation and lung tumor progression. Loss of the central clock components led to increased c-Myc expression, enhanced proliferation, and metabolic dysregulation. Our findings demonstrate that both systemic and somatic disruption of circadian rhythms contribute to cancer progression

Environment Impacts the Metabolic Dependencies of Ras-Driven Non-Small Cell Lung Cancer

Cultured cells convert glucose to lactate, and glutamine is the major source of tricarboxylic acid (TCA)-cycle carbon, but whether the same metabolic phenotype is found in tumors is less studied. We infused mice with lung cancers with isotope-labeled glucose or glutamine and compared the fate of these nutrients in tumor and normal tissue. As expected, lung tumors exhibit increased lactate production from glucose. However, glutamine utilization by both lung tumors and normal lung was minimal, with lung tumors showing increased glucose contribution to the TCA cycle relative to normal lung tissue. Deletion of enzymes involved in glucose oxidation demonstrates that glucose carbon contribution to the TCA cycle is required for tumor formation. These data suggest that understanding nutrient utilization by tumors can predict metabolic dependencies of cancers in vivo. Furthermore, these data argue that the in vivo environment is an important determinant of the metabolic phenotype of cancer cells.National Science Foundation (U.S.) (Grant T32GM007287