But From This Moment On We Know Nothing

As a student enrolled in Virginia Commonwealth University\u27s Department of Craft/Material Studies\u27 Master of Fine Arts Graduate Degree program, Jacob A. Vincent\u27s sole obligation to the world for the time period beginning in September of 2010 and continuing through April of 2012 was to dwell on things, and to eventually produce something tangible as a result. Having charged himself with the burden of indulging in the task of re-contextualizing all of existence, and ensuring that his peers and professors knew how vitally important that is, this thesis outlines select aspects of his research methodologies and provides a glimpse into the resultant conclusions

PHYSICO CHEMICAL ANALYSIS OF GROUND WATER NEAR MUNICIPAL SOLID WASTE DUMPING SITES IN ARUMUGANERI, THOOTHUKUDI DISTRICT, TAMILNADU, INDIA

Ground water samples in and around from the dumpsite located in Arumuganeri were studied to assess the impact of Municipal solid waste on the ground water resources. Ground water samples were collected from the 5 different bore-wells in and around the dumpsites. The collected water samples were analyzed for parameters of Total Dissolved Solids (TDS), Total Alkalinity (TA), Total hardness, chloride and dissolved oxygen. The results were observed in each sample , compared with standards WHO, ICMR, ISI and thus  an  attempt  was  made  to  ascertain  whether  the quality  of  ground  water  is  fit  or  not  for  drinking  and  other  purposes

Vasoconstrictors: a tale of two circulations

A cell can not survive without oxygen (O2) or nutrients. A single-celled organism can get both O2 and nutrients by simple diffusion. Since our body is built up of ~100 trillion (1014) cells, most of which never come into contact with outside air, we need to transport both O2 and nutrients actively in order to get them to all of our cells. The substance that mammals, like ourselves, use to accomplish this is blood. Blood is transported through the body using blood vessels, the complex of which is called the circulation. The movement of blood through the circulation is not a passive process, but is driven by one of the most amazing achievements of evolution: the heart (Fig. 1). The heart is a pump that, on average, contracts 60 times each minute at rest, a number which can increase to 200 contractions during maximum exercise. By contracting, the heart builds up the pressure, in the arterial side of the circulation, which is required for blood to flow

Spike-Timing-Dependent Plasticity in the Intact Brain: Counteracting Spurious Spike Coincidences

A computationally rich algorithm of synaptic plasticity has been proposed based on the experimental observation that the sign and amplitude of the change in synaptic weight is dictated by the temporal order and temporal contiguity between pre- and postsynaptic activities. For more than a decade, this spike-timing-dependent plasticity (STDP) has been studied mainly in brain slices of different brain structures and cultured neurons. Although not yet compelling, evidences for the STDP rule in the intact brain, including primary sensory cortices, have been provided lastly. From insects to mammals, the presentation of precisely timed sensory inputs drives synaptic and functional plasticity in the intact central nervous system, with similar timing requirements than the in vitro defined STDP rule. The convergent evolution of this plasticity rule in species belonging to so distant phylogenic groups points to the efficiency of STDP, as a mechanism for modifying synaptic weights, as the basis of activity-dependent development, learning and memory. In spite of the ubiquity of STDP phenomena, a number of significant variations of the rule are observed in different structures, neuronal types and even synapses on the same neuron, as well as between in vitro and in vivo conditions. In addition, the state of the neuronal network, its ongoing activity and the activation of ascending neuromodulatory systems in different behavioral conditions have dramatic consequences on the expression of spike-timing-dependent synaptic plasticity, and should be further explored

Spin fragmentation of Bose-Einstein condensates with antiferromagnetic interactions

We study spin fragmentation of an antiferromagnetic spin 1 condensate in the presence of a quadratic Zeeman (QZ) effect breaking spin rotational symmetry. We describe how the QZ effect turns a fragmented spin state, with large fluctuations of the Zeemans populations, into a regular polar condensate, where atoms all condense in the $m=0$ state along the field direction. We calculate the average value and variance of the Zeeman state $m=0$ to illustrate clearly the crossover from a fragmented to an unfragmented state. The typical width of this crossover is $q \sim k_B T/N$, where $q$ is the QZ energy, $T$ the spin temperature and $N$ the atom number. This shows that spin fluctuations are a mesoscopic effect that will not survive in the thermodynamic limit $N\rightarrow \infty$, but are observable for sufficiently small atom number.Comment: submitted to NJ

Pulsed frequency-shifted feedback laser for laser guide stars: intracavity preamplifier

International audienceIntensive use of Laser Guide Star (LGS) with the new generation of Extremely Large Telescopes and Hypertelescopes will requires the use of more efficient lasers to surmount the novel limitations and aberrations. The Pulsed Frequency Shifted Feedback (FSF) laser we have developed overcomes the saturation of sodium atoms and solves new problems. This work presents a highly efficient solution for operating pulsed FSF lasers. For the first time, an intra-cavity preamplifier achieves a gain of 104 and more than 40 μJ per pulse, with a near diffraction limited beam and without Amplified Spontaneous Emission. Endurance tests have shown that good performance is maintained over several hundred hours