The Chemical Senses

Long-standing neglect of the chemical senses in the philosophy of perception is due, mostly, to their being regarded as ‘lower’ senses. Smell, taste, and chemically irritated touch are thought to produce mere bodily sensations. However, empirically informed theories of perception can show how these senses lead to perception of objective properties, and why they cannot be treated as special cases of perception modelled on vision. The senses of taste, touch, and smell also combine to create unified perceptions of flavour. The nature of these multimodal experiences and the character of our awareness of them puts pressure on the traditional idea that each episode of perception goes one or other of the five senses. Thus, the chemical senses, far from being peripheral to the concerns of the philosophy of perception, may hold important clues to the multisensory nature of perception in general

First generation interferometers

The status and plans for the first generation long baseline suspended mass interferometers TAMA, GEO, LIGO and Virgo are presented, as well as the expected performances

Amaldi Meeting Introduction

Welcome to Caltech and the 3rd Edoardo Amaldi Conference on Gravitational Waves. Obviously, something must be very interesting to bring more than 250 scientists from around the world to Pasadena in July for this particular meeting. In fact, July in Southern California does have many attractions, in addition to the good weather and cool nights. For this conference, we have arranged a visit to the new Getty Museum on our excursion day. This is meant to make your stay more pleasant, but is not the real reason we have gathered here. This meeting addresses the detection of gravitational waves, a much-anticipated event

Neural systems supporting navigation

Highlights: • Recent neuroimaging and electrophysiology studies have begun to shed light on the neural dynamics of navigation systems. • Computational models have advanced theories of how entorhinal grid cells and hippocampal place cells might serve navigation. • Hippocampus and entorhinal cortex provide complementary representations of routes and vectors for navigation. Much is known about how neural systems determine current spatial position and orientation in the environment. By contrast little is understood about how the brain represents future goal locations or computes the distance and direction to such goals. Recent electrophysiology, computational modelling and neuroimaging research have shed new light on how the spatial relationship to a goal may be determined and represented during navigation. This research suggests that the hippocampus may code the path to the goal while the entorhinal cortex represents the vector to the goal. It also reveals that the engagement of the hippocampus and entorhinal cortex varies across the different operational stages of navigation, such as during travel, route planning, and decision-making at waypoints

Eight microprocessor-based instrument data systems in the Galileo Orbiter spacecraft

Instrument data systems consist of a microprocessor, 3K bytes of Read Only Memory and 3K bytes of Random Access Memory. It interfaces with the spacecraft data bus through an isolated user interface with a direct memory access bus adaptor, and/or parallel data from instrument devices such as registers, buffers, analog to digital converters, multiplexers, and solid state sensors. These data systems support the spacecraft hardware and software communication protocol, decode and process instrument commands, generate continuous instrument operating modes, control the instrument mechanisms, acquire, process, format, and output instrument science data

The fossil tragulids of the Siwalik Formations of Southern Asia

Tragulids are common in the Early Miocene through Pliocene Siwalik faunas of the Indian Subcontinent where they are represented by as many as 17 species. Large collections of Siwalik fossils have recently been made by collaborative projects from Harvard University, the University of Arizona, the Geological Survey of Pakistan, and the Pakistan Museum of Natural History. The collections together comprise over 3700 specimens, including dental, cranial, and postcranial elements. Most of this fossil material is from northern and southwestern Pakistan from well-dated stratigraphic sections. The oldest definite tragulids are from the Early Miocene Vihowa Formation and are around 18.7 Ma, while the youngest are in the Pliocene Tatrot Formation and are 3.3 Ma. The fossil tragulids of the Siwaliks differ from the extant species in a number of ways. Importantly, they have a much wider range of body sizes, ranging from 1 to nearly 76 kg. Consequently the small species overlap with the smallest species of extant Tragulus, while the large species approach medium size bovids and cervids. Compared to other ruminants, Siwalik tragulids are also relatively abundant and species rich. Although the status of some described species is uncertain, preliminary analysis indicates there are many as yet undescribed species. Three genera are known and typically at least four species co-exist at any one time during the Miocene. The history of the south Asian tragulids can be correlated to documented environmental changes. The Siwalik deposits formed in a large fluvial system, with mostly forested or wooded low relief floodplains having abundant cover and fruit. Isotopic analyses of tooth enamel and soil carbonates indicate the vegetation was dominated by C3 plants until 9 Ma, after which there was a shift to a more seasonally dry monsoon climate, undoubtedly accounting for a Late Miocene change in the relative abundance of tragulids