Mach's Principle and Model for a Broken Symmetric Theory of Gravity

We investigate spontaneous symmetry breaking in a conformally invariant gravitational model. In particular, we use a conformally invariant scalar tensor theory as the vacuum sector of a gravitational model to examine the idea that gravitational coupling may be the result of a spontaneous symmetry breaking. In this model matter is taken to be coupled with a metric which is different but conformally related to the metric appearing explicitly in the vacuum sector. We show that after the spontaneous symmetry breaking the resulting theory is consistent with Mach's principle in the sense that inertial masses of particles have variable configurations in a cosmological context. Moreover, our analysis allows to construct a mechanism in which the resulting large vacuum energy density relaxes during evolution of the universe.Comment: 9 pages, no figure

Infection control in dental health care during and after the SARS-CoV-2 outbreak

COVID-19 is an emerging infectious disease caused by the widespread transmission of the coronavirus SARS-CoV-2. Some of those infected become seriously ill. Others do not show any symptoms, but can still contribute to transmission of the virus. SARS-CoV-2 is excreted in the oral cavity and can be spread via aerosols. Aerosol generating procedures in dental health care can increase the risk of transmission of the virus. Due to the risk of infection of both dental healthcare workers and patients, additional infection control measures for all patients are strongly recommended when providing dental health care. Consideration should be given to which infection control measures are necessary when providing care in both the current situation and in the future

Spreading Dynamics of Polymer Nanodroplets

The spreading of polymer droplets is studied using molecular dynamics simulations. To study the dynamics of both the precursor foot and the bulk droplet, large drops of ~200,000 monomers are simulated using a bead-spring model for polymers of chain length 10, 20, and 40 monomers per chain. We compare spreading on flat and atomistic surfaces, chain length effects, and different applications of the Langevin and dissipative particle dynamics thermostats. We find diffusive behavior for the precursor foot and good agreement with the molecular kinetic model of droplet spreading using both flat and atomistic surfaces. Despite the large system size and long simulation time relative to previous simulations, we find no evidence of hydrodynamic behavior in the spreading droplet.Comment: Physical Review E 11 pages 10 figure

An observed 20-year time series of Agulhas leakage

We provide a time series of Agulhas leakage anomalies over the last 20-years from satellite altimetry. Until now, measuring the interannual variability of Indo-Atlantic exchange has been the major barrier in the investigation of the dynamics and large scale impact of Agulhas leakage. We compute the difference of transport between the Agulhas Current and Agulhas Return Current, which allows us to deduce Agulhas leakage. The main difficulty is to separate the Agulhas Return Current from the southern limb of the subtropical "supergyre" south of Africa. For this purpose, an algorithm that uses absolute dynamic topography data is developed. The algorithm is applied to a state-of-the-art ocean model. The comparison with a Lagrangian method to measure the leakage allows us to validate the new method. An important result is that it is possible to measure Agulhas leakage in this model using the velocity field along a section that crosses both the Agulhas Current and the Agulhas Return Current. In the model a good correlation is found between measuring leakage using the full depth velocities and using only the surface geostrophic velocities. This allows us to extend the method to along-track absolute dynamic topography from satellites. It is shown that the accuracy of the mean dynamic topography does not allow us to determine the mean leakage but that leakage anomalies can be accurately computed

Річард Смоллі і знамениті «десять вересневих днів»

У вересні цього року виповнюється 27 років, як було відкрито фулерен — нову сфероподібну форму вуглецю. Ця подія буквально приголомшила вчених, які на той час вважали, що про елементарний вуглець їм відомо практично все. Історія відкриття цієї речовини досить незвичайна. Ще в 1971 р. можливість існування молекули фулерену була передбачена японським ученим Е. Осавою (E. Osawa), за два роки радянські хіміки-теоретики Д.А. Бочвар і О.Г. Гальперн квантово-хімічними розрахунками підтвердили стабільність молекули С60, і лише у 1985 р. Р. Смоллі, Р. Керл та Г. Крото експериментально отримали кластери із 60 атомів вуглецю в стійкій формі, яку вони пояснили структурою молекули у вигляді футбольного м’яча. Натхненнику цього відкриття, видатному вченому, нобелівському лауреату, активному популяризатору нанотехнологій Річарду Смоллі присвячено цей матеріал.В сентябре этого года исполняется 27 лет с момента открытия фуллерена — новой сферообразной формы углерода. Это событие буквально потрясло ученых, которые в то время считали, что об элементарном углероде им известно практически все. История открытия этого вещества довольно необычна. Еще в 1971 г. возможность су ществования молекулы фуллерена была предсказана японским ученым Е. Осавой (E. Osawa), через два года советские химики-теоретики Д.А. Бочвар и Е.Г. Гальперн с помощью квантово-химических расчетов подтвердили стабильность молекулы С60, и только в 1985 г. Р. Смолли, Р. Керл и Г. Крото экспериментально получили кластеры из 60 атомов углерода в устойчивой форме, которую они объяснили структурой молекулы в виде футбольного мяча. Вдохновителю этого открытия, выдающемуся ученому, нобелевскому лауреату, активному популяризатору нанотехнологий Ричарду Смолли посвящен этот материал.27 years since the discovery of fullerene, the new form of carbon, is observed in September of this year. This event has literally shocked scientists, who believed at that time that they know almost everything about the elementary carbon. History of this discovery is rather unusual. Long ago, in 1971 the possibility of the existence of a fullerene molecule was predicted by an young Japanese scientist E. Osawa. Then two Soviet chemists and theorists D.A. Bochvar and E.G. Hal pern confirm the stability of the C60 molecule using quantum chemical calculations, and in 1985 at last R. Smalley, R. Curl and H. Kroto experimentally obtained clusters of 60 carbon atoms in a sustainable form. They explained the structure of this molecule as the structure of a soccer ball. This material is devoted to the inspirer of this discovery, an outstanding scientist, Nobel laureate, active popularizer of nanotechnology — Richard Smalley

Asexual and sexual reproduction are two separate developmental pathways in a <i>Termitomyces</i> species

Although mutualistic symbioses per definition are beneficial for interacting species, conflict may arise if partners reproduce independently. We address how this reproductive conflict is regulated in the obligate mutualistic symbiosis between fungus-growing termites and Termitomyces fungi. Even though the termites and their fungal symbiont disperse independently to establish new colonies, dispersal is correlated in time. The fungal symbiont typically forms mushrooms a few weeks after the colony has produced dispersing alates. It is thought that this timing is due to a trade-off between alate and worker production; alate production reduces resources available for worker production. As workers consume the fungus, reduced numbers of workers will allow mushrooms to 'escape' from the host colony. Here, we test a specific version of this hypothesis: the typical asexual structures found in all species of Termitomyces-nodules-are immature stages of mushrooms that are normally harvested by the termites at a primordial stage. We refute this hypothesis by showing that nodules and mushroom primordia are macro- and microscopically different structures and by showing that in the absence of workers, primordia do, and nodules do not grow out into mushrooms. It remains to be tested whether termite control of primordia formation or of primordia outgrowth mitigates the reproductive conflict.</p

Mesoscale perturbations control inter-ocean exchange south of Africa

The quantification of inter-ocean leakage from the South Indian to the South Atlantic Ocean is an important measure for the role of the Agulhas system in the global thermohaline circulation. To explore the specific role of mesoscale variability (such as Agulhas rings and Mozambique eddies) in this process a high-resolution model (based on NEMO-ORCA) for the Agulhas region has been set up. It is nested into a global coarse-resolution model. The high-resolution nest captures all salient features of the greater Agulhas region, including the upstream perturbations of the Agulhas Current and Natal Pulses along the African coast. A comparison of the inter-ocean exchange in the high-resolution nest with its coarse resolution counterpart reveals that the latter significantly over-estimates the amount of water flowing into the Atlantic Ocean, demonstrating the need to explicitly simulate the mesoscale features. A sensitivity experiment that excludes the upstream perturbations revealed no difference in the amount of inter-ocean exchange. However, the realistic representation of Agulhas rings and their drift path into the South Atlantic depends on the simulation of those upstream perturbations

A diet rich in unsaturated fatty acids prevents progression toward heart failure in a rabbit model of pressure and volume overload

Background-During heart failure (HF), cardiac metabolic substrate preference changes from fatty acid (FA) toward glucose oxidation. This change may cause progression toward heart failure. We hypothesize that a diet rich in FAs may prevent this process, and that dietary 3-FAs have an added antiarrhythmic effect based on action potential (AP) shortening in animals with HF. Methods and Results-Rabbits were fed a diet containing 1.25% (w/w) high oleic sunflower oil (HF-9, N 11), 1.25% fish oil (HF-3, N11), or no supplement (HF-control, N8). Subsequently, HF was induced by volume and pressure overload. After 4 months, HF-parameters were assessed, electrocardiograms were recorded, and blood and ventricular tissue were collected. Myocytes were isolated for patch clamp or intracellular Ca2-recordings to study electrophysiologic remodeling and arrhythmogenesis. Both the HF-9 and the HF-3 groups had larger myocardial FA oxidation capacity than HF control. The HF-3 group had significantly lower mean ( SEM) relative heart and lung weight (3.3-0.13 and 3.2-0.12 g kg 1, respectively) than HF control (4.8-0.30 and 4.5-0.23), and shorter QTc intervals (167-2.6 versus 182-6.4). The HF-9 also displayed a significantly reduced relative heart weight (3.6-0.26), but had similar QTc (179-4.3) compared with HF control. AP duration in the HF-3 group was 20% shorter due to increased Ito1 and IK1 and triggered activity, and Ca2-aftertransients were less than in the HF-9 group. Conclusions-Dietary unsaturated FAs started prior to induction of HF prevent hypertrophy and HF. In addition, fish oil FAs prevent HF-induced electrophysiologic remodeling and arrhythmias. © 2012 American Heart Association, Inc