Radio-echo sounding and ice volume estimates of western Nordenskiöld Land glaciers, Svalbard

As part of ongoing work to obtain a reliable estimate of the total ice volume of Svalbard glaciers and their potential contribution to sea-level rise, we present here volume calculations, with detailed error estimates, for ten glaciers on western Nordenskiöld Land, central Spitsbergen, Svalbard. The volume estimates are based upon a dense net of GPR-retrieved ice thickness data collected over several field campaigns spanning the period 1999-2012. On the basis of the pattern of scattering in theradargrams, we also analyse the hydrothermal structure of these glaciers.

Solenes [sic] i grandiosas fiestas, q[ue] la noble i leal ciudad de Valencia a echo por la Beatificacion desu Santo Pastor i Padre D. Tomas de Villanueva...

Sign. : []\p8\s, A-Z-\p8\s, Aa-Nn\p8\s, Oo\p4\s

Jardin engañoso : nueua relacion, y curioso romance, en que se refieren los amores de don Fadrique de Alvara, don Joseph de Alvara, doña Constanza, y doña Theodosia : dase cuenta, como don Fadrique dio muerte a su hermano, y lo echo en un pozo y le entrego el alma al demonio, por gozar de doña Constanza, y como caso con doña Theodosia ... : primera parte

Pie de imp. consta en col

Vista de dos Templos antiguos en la plaza del Eco de Sagunto [Material gráfico] = Vue de deux Temples antiques sur la Place de l'Echo à Sagonte = View of two antique Temples in the square of the Echo at Sagonta

Estampado junto a "Plano de la Plaza del Eco"

Plano de la Plaza del Eco [Material gráfico] = Plan de la Place de l'Echo = Plan of the Square of the Echo

Estampado en la misma hoja con: "Vista de dos Templos antiguos en la plaza del Eco de Sagunto"

Echo-delay resolution in sonar images of the big brown bat, Eptesicus fuscus

Echolocating big brown bats (Eptesicus fuscus) broadcast ultrasonic frequency-modulated (FM) biosonar sounds (20–100 kHz frequencies; 10–50 μs periods) and perceive target range from echo delay. Knowing the acuity for delay resolution is essential to understand how bats process echoes because they perceive target shape and texture from the delay separation of multiple reflections. Bats can separately perceive the delays of two concurrent electronically generated echoes arriving as little as 2 μs apart, thus resolving reflecting points as close together as 0.3 mm in range (two-point threshold). This two-point resolution is roughly five times smaller than the shortest periods in the bat’s sounds. Because the bat’s broadcasts are 2,000–4,500 μs long, the echoes themselves overlap and interfere with each other, to merge together into a single sound whose spectrum is shaped by their mutual interference depending on the size of the time separation. To separately perceive the delays of overlapping echoes, the bat has to recover information about their very small delay separation that was transferred into the spectrum when the two echoes interfered with each other, thus explicitly reconstructing the range profile of targets from the echo spectrum. However, the bat’s 2-μs resolution limit is so short that the available spectral cues are extremely limited. Resolution of delay seems overly sharp just for interception of flying insects, which suggests that the bat’s biosonar images are of higher quality to suit a wider variety of orientation tasks, and that biosonar echo processing is correspondingly more sophisticated than has been suspected.

Memory's echo: Vivid remembering reactivates sensory-specific cortex

A fundamental question in human memory is how the brain represents sensory-specific information during the process of retrieval. One hypothesis is that regions of sensory cortex are reactivated during retrieval of sensory-specific information (1). Here we report findings from a study in which subjects learned a set of picture and sound items and were then given a recall test during which they vividly remembered the items while imaged by using event-related functional MRI. Regions of visual and auditory cortex were activated differentially during retrieval of pictures and sounds, respectively. Furthermore, the regions activated during the recall test comprised a subset of those activated during a separate perception task in which subjects actually viewed pictures and heard sounds. Regions activated during the recall test were found to be represented more in late than in early visual and auditory cortex. Therefore, results indicate that retrieval of vivid visual and auditory information can be associated with a reactivation of some of the same sensory regions that were activated during perception of those items.