An introduction to the "Dialogues Concerning Natural Religion" of David Hume

In professing to call attention to this often forgotten work of the great Scottish Philosopher one can- not help noticing how very similar the reception accorded to it by the outside world has been to its treatment at the hands of the author himself. During his lifetime he kept it in the safe obscurity of his study drawer, where it lay until the day of his death. The plan of the Dialogues had been clearly thought out by Hume as early as 1750 and the active period of his contribution to philosophy proper having closed almost in the same year this excursion of his into natural theology might most fitly have been presented to his readers at once, especially if, as it seems to us now, it may he rightly regarded as the crown and consummation of his earlier speculations. indeed some such conception of the relation of the Dialogues to his other works underlies the outlining of his scheme upon its first page, where he founds his method "on the saying of" an ancient (Chrysippus) that students of philosophy ought first to learn Logics, then Ethics, next Physics, "last of all the nature of the Gods.

Introduction to Social Neuroscience: Gene, Environment, Brain, Body

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87184/1/j.1749-6632.2011.06154.x.pd

Tomographic reconstruction of treponemal cytoplasmic filaments reveals novel bridging and anchoring components

An understanding of the involvement of bacterial cytoplasmic filaments in cell division requires the elucidation of the structural organization of those filamentous structures. Treponemal cytoplasmic filaments are composed of one protein, CfpA, and have been demonstrated to be involved in cell division. In this study, we used electron tomography to show that the filaments are part of a complex with a novel molecular organization that includes at least two distinct features decorating the filaments. One set of components appears to anchor the filaments to the cytoplasmic membrane. The other set of components appears to bridge the cytoplasmic filaments on the cytoplasmic side, and to be involved in the interfilament spacing within the cell. The filaments occupy between 3 and 18% of the inner surface of the cytoplasmic membrane. These results reveal a novel filamentous molecular organization of independent filaments linked by bridges and continuously anchored to the membrane

Crater population and resurfacing of the Martian north polar layered deposits

Present-day accumulation in the north polar layered deposits (NPLD) is thought to occur via deposition on the north polar residual cap. Understanding current mass balance in relation to current climate would provide insight into the climatic record of the NPLD. To constrain processes and rates of NPLD resurfacing, a search for craters was conducted using images from the Mars Reconnaissance Orbiter Context Camera. One hundred thirty craters have been identified on the NPLD, 95 of which are located within a region defined to represent recent accumulation. High Resolution Imaging Science Experiment images of craters in this region reveal a morphological sequence of crater degradation that provides a qualitative understanding of processes involved in crater removal. A classification system for these craters was developed based on the amount of apparent degradation and infilling and where possible depth/diameter ratios were determined. The temporal and spatial distribution of crater degradation is interpreted to be close to uniform. Through comparison of the size-frequency distribution of these craters with the expected production function, the craters are interpreted to be an equilibrium population with a crater of diameter D meters having a lifetime of ~30.75D^(1.14) years. Accumulation rates within these craters are estimated at 7.2D^(−0.14) mm/yr, which corresponds to values of ~3–4 mm/yr and are much higher than rates thought to apply to the surrounding flat terrain. The current crater population is estimated to have accumulated in the last ~20 kyr or less