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PhD Student at École de technologie supérieure studying Carbon Nanotube MEMS.

PINBOARD SUMMARY

Arguably the most complex branch of Physics, it can actually be broken down into few basic theories

What is Quantum Mechanics Quantum Mechanics can be defined as the study of the interaction of subatomic particles with each other or with electromagnetic radiation. As simple as it may sound, the concepts of Quantum Physics sometimes directly contradict Classical Physics and hence can be very difficult to grasp. However, this branch of Physics has greatly helped us to better understand the building blocks of matter and all universe. Wave-Particle Duality Quantum theory suggests that all elementary particles can behave both as a particle and a wave. This theory was first formulated by Einstein who studied the work of Max Planck and modified it accordingly to fit the model. Einstein arrived at the conclusion that light is actually made of particles called "Photons". Niels Bohr through his experiments further verified Einstein's concept in what can be thought of as the birth of Quantum Physics. Principle of Superposition Erwin Schrodinger designed a thought experiment which involved a cat inside a box with a radioactive source. He argued that the chance of the cat surviving or dying is 50% but according to Quantum Physics at the instant, before the box is opened, the cat is equal parts alive and dead. only when the box is opened do we see a definitive result but until then it is all probability. This translates to the fact that Quantum objects can exist in 2 states at once which forms the Principle of superposition which is again a consequence of the wave-particle duality. Uncertainty Principle Heisenberg proposed the famous "Uncertainty Principle" which states that since the elementary particles have a dual nature, one can never predict the exact speed and the exact position of the particle at the same time. Uncertainty arises due to measurement- measuring position changes the velocity of the body and vice versa due to the dual nature of subatomic particles.

10 ITEMS PINNED

Life history trade-off moderates model predictions of diversity loss from climate change.

Abstract: Climate change can trigger species range shifts, local extinctions and changes in diversity. Species interactions and dispersal capacity are important mediators of community responses to climate change. The interaction between multispecies competition and variation in dispersal capacity has recently been shown to exacerbate the effects of climate change on diversity and to increase predictions of extinction risk dramatically. Dispersal capacity, however, is part of a species' overall ecological strategy and are likely to trade off with other aspects of its life history that influence population growth and persistence. In plants, a well-known example is the trade-off between seed mass and seed number. The presence of such a trade-off might buffer the diversity loss predicted by models with random but neutral (i.e. not impacting fitness otherwise) differences in dispersal capacity. Using a trait-based metacommunity model along a warming climatic gradient the effect of three different dispersal scenarios on model predictions of diversity change were compared. Adding random variation in species dispersal capacity caused extinctions by the introduction of strong fitness differences due an inherent property of the dispersal kernel. Simulations including a fitness-equalising trade-off based on empirical relationships between seed mass (here affecting dispersal distance, establishment probability, and seedling biomass) and seed number (fecundity) maintained higher initial species diversity and predicted lower extinction risk and diversity loss during climate change than simulations with variable dispersal capacity. Large seeded species persisted during climate change, but developed lags behind their climate niche that may cause extinction debts. Small seeded species were more extinction-prone during climate change but tracked their niches through dispersal and colonisation, despite competitive resistance from residents. Life history trade-offs involved in coexistence mechanisms may increase community resilience to future climate change and are useful guides for model development.

Pub.: 19 May '17, Pinned: 22 May '17