A dusty veil shading Betelgeuse during its Great Dimming.

Red supergiants are the most common final evolutionary stage of stars that have initial masses between 8 and 35 times that of the Sun1. During this stage, which lasts roughly 100,000 years1, red supergiants experience substantial mass loss. However, the mechanism for this mass loss is unknown2. Mass loss may affect the evolutionary path, collapse and future supernova light curve3 of a red supergiant, and its ultimate fate as either a neutron star or a black hole4. From November 2019 to March 2020, Betelgeuse-the second-closest red supergiant to Earth (roughly 220 parsecs, or 724 light years, away)5,6-experienced a historic dimming of its visible brightness. Usually having an apparent magnitude between 0.1 and 1.0, its visual brightness decreased to 1.614 ± 0.008 magnitudes around 7-13 February 20207-an event referred to as Betelgeuse's Great Dimming. Here we report high-angular-resolution observations showing that the southern hemisphere of Betelgeuse was ten times darker than usual in the visible spectrum during its Great Dimming. Observations and modelling support a scenario in which a dust clump formed recently in the vicinity of the star, owing to a local temperature decrease in a cool patch that appeared on the photosphere. The directly imaged brightness variations of Betelgeuse evolved on a timescale of weeks. Our findings suggest that a component of mass loss from red supergiants8 is inhomogeneous, linked to a very contrasted and rapidly changing photosphere.

The expanding fireball of Nova Delphini 2013.

A classical nova occurs when material accreting onto the surface of a white dwarf in a close binary system ignites in a thermonuclear runaway. Complex structures observed in the ejecta at late stages could result from interactions with the companion during the common-envelope phase. Alternatively, the explosion could be intrinsically bipolar, resulting from a localized ignition on the surface of the white dwarf or as a consequence of rotational distortion. Studying the structure of novae during the earliest phases is challenging because of the high spatial resolution needed to measure their small sizes. Here we report near-infrared interferometric measurements of the angular size of Nova Delphini 2013, starting one day after the explosion and continuing with extensive time coverage during the first 43 days. Changes in the apparent expansion rate can be explained by an explosion model consisting of an optically thick core surrounded by a diffuse envelope. The optical depth of the ejected material changes as it expands. We detect an ellipticity in the light distribution, suggesting a prolate or bipolar structure that develops as early as the second day. Combining the angular expansion rate with radial velocity measurements, we derive a geometric distance to the nova of 4.54 ± 0.59 kiloparsecs from the Sun.

Forward shift of feeding buzz components of dolphins and belugas during associative learning reveals a likely connection to reward expectation, pleasure and brain dopamine activation.

For many years, we heard sounds associated with reward from dolphins and belugas. We named these pulsed sounds victory squeals (VS), as they remind us of a child's squeal of delight. Here we put these sounds in context with natural and learned behavior. Like bats, echolocating cetaceans produce feeding buzzes as they approach and catch prey. Unlike bats, cetaceans continue their feeding buzzes after prey capture and the after portion is what we call the VS. Prior to training (or conditioning), the VS comes after the fish reward; with repeated trials it moves to before the reward. During training, we use a whistle or other sound to signal a correct response by the animal. This sound signal, named a secondary reinforcer (SR), leads to the primary reinforcer, fish. Trainers usually name their whistle or other SR a bridge, as it bridges the time gap between the correct response and reward delivery. During learning, the SR becomes associated with reward and the VS comes after the SR rather than after the fish. By following the SR, the VS confirms that the animal expects a reward. Results of early brain stimulation work suggest to us that SR stimulates brain dopamine release, which leads to the VS. Although there are no direct studies of dopamine release in cetaceans, we found that the timing of our VS is consistent with a response after dopamine release. We compared trained vocal responses to auditory stimuli with VS responses to SR sounds. Auditory stimuli that did not signal reward resulted in faster responses by a mean of 151 ms for dolphins and 250 ms for belugas. In laboratory animals, there is a 100 to 200 ms delay for dopamine release. VS delay in our animals is similar and consistent with vocalization after dopamine release. Our novel observation suggests that the dopamine reward system is active in cetacean brains.

Dolphin whistles: a functional misnomer revealed by heliox breathing.

Delphinids produce tonal whistles shaped by vocal learning for acoustic communication. Unlike terrestrial mammals, delphinid sound production is driven by pressurized air within a complex nasal system. It is unclear how fundamental whistle contours can be maintained across a large range of hydrostatic pressures and air sac volumes. Two opposing hypotheses propose that tonal sounds arise either from tissue vibrations or through actual whistle production from vortices stabilized by resonating nasal air volumes. Here, we use a trained bottlenose dolphin whistling in air and in heliox to test these hypotheses. The fundamental frequency contours of stereotyped whistles were unaffected by the higher sound speed in heliox. Therefore, the term whistle is a functional misnomer as dolphins actually do not whistle, but form the fundamental frequency contour of their tonal calls by pneumatically induced tissue vibrations analogous to the operation of vocal folds in terrestrial mammals and the syrinx in birds. This form of tonal sound production by nasal tissue vibrations has probably evolved in delphinids to enable impedance matching to the water, and to maintain tonal signature contours across changes in hydrostatic pressures, air density and relative nasal air volumes during dives.

Management of proximal femoral fractures 2011: Association of Anaesthetists of Great Britain and Ireland.

There should be protocol-driven, fast-track admission of patients with hip fractures through the emergency department. Patients with hip fractures require multidisciplinary care, led by orthogeriatricians. Surgery is the best analgesic for hip fractures. Surgical repair of hip fractures should occur within 48 hours of hospital admission. Surgery and anaesthesia must be undertaken by appropriately experienced surgeons and anaesthetists. There must be high-quality communication between clinicians and allied health professionals. Early mobilisation is a key part of the management of patients with hip fractures. Pre-operative management should include consideration of planning for discharge from hospital. Measures should be taken to prevent secondary falls. 10. Continuous audit and targeted research is required in order to inform and improve the management of patients with hip fracture.

Vocal reporting of echolocation targets: dolphins often report before click trains end.

Bottlenose dolphins (Tursiops truncatus) wore opaque suction cups over their eyes while stationing behind an acoustically opaque door. This put the dolphins in a known position and orientation. When the door opened, the dolphin clicked to detect targets. Trainers specified that Dolphin S emit a whistle if the target was a 7.5 cm water filled sphere, or a pulse burst if the target was a rock. S remained quiet if there was no target. Dolphin B whistled for the sphere. She remained quiet for rock and for no target. Thus, S had to choose between three different responses, whistle, pulse burst, or remain quiet. B had to choose between two different responses, whistle or remain quiet. S gave correct vocal responses averaging 114 ms after her last echolocation click (range 182 ms before and 219 ms after the last click). Average response for B was 21 ms before her last echolocation click (range 250 ms before and 95 ms after the last click in the train). More often than not, B began her whistle response before her echolocation train ended. The findings suggest separate neural pathways for generation of response vocalizations as opposed to echolocation clicks.

Cetacean brain evolution: Dwarf sperm whale (Kogia sima) and common dolphin (Delphinus delphis) - An investigation with high-resolution 3D MRI.

This study compares a whole brain of the dwarf sperm whale (Kogia sima) with that of a common dolphin (Delphinus delphis) using high-resolution magnetic resonance imaging (MRI). The Kogia brain was scanned with a Siemens Trio Magnetic Resonance scanner in the three main planes. As in the common dolphin and other marine odontocetes, the brain of the dwarf sperm whale is large, with the telencephalic hemispheres remarkably dominating the brain stem. The neocortex is voluminous and the cortical grey matter thin but expansive and densely convoluted. The corpus callosum is thin and the anterior commissure hard to detect whereas the posterior commissure is well-developed. There is consistency as to the lack of telencephalic structures (olfactory bulb and peduncle, olfactory ventricular recess) and neither an occipital lobe of the telencephalic hemisphere nor the posterior horn of the lateral ventricle are present. A pineal organ could not be detected in Kogia. Both species show a tiny hippocampus and thin fornix and the mammillary body is very small whereas other structures of the limbic system are well-developed. The brain stem is thick and underlies a large cerebellum, both of which, however, are smaller in Kogia. The vestibular system is markedly reduced with the exception of the lateral (Deiters') nucleus. The visual system, although well-developed in both species, is exceeded by the impressive absolute and relative size of the auditory system. The brainstem and cerebellum comprise a series of structures (elliptic nucleus, medial accessory inferior olive, paraflocculus and posterior interpositus nucleus) showing characteristic odontocete dimensions and size correlations. All these structures seem to serve the auditory system with respect to echolocation, communication, and navigation.

Dolphin lung collapse and intramuscular circulation during free diving: evidence from nitrogen washout.

Intramuscular nitrogen tensions in Tursiops truncatus after a schedule of repetitive ocean dives suggest a lung collapse depth of about 70 meters and suggest that intramuscular circulation is maintained during unrestrained diving in the open ocean. Therefore, the bottle-nosed dolphin is not protected by lung collapse from the decompression hazards of dives to depths shallower than 70 meters.

Respiration and deep diving in the bottlenose porpoise.

A bottlenose porpoise was trained to dive untethered in the open ocean and to exhale into an underwater collecting funnel before surfacing from prescribed depths down to 300 meters. The animal was also taught to hold its breath for periods up to 4 minutes at the surface and then blow in the funnel. Alveolar collapse is probably complete at around 100 meters, and little pulmonary respiratory exchange occurs below that depth. Thoracic collapse was observ visually at 10 to 50 meters and by underwater television to 300 meters.

Anesthetization of porpoises for major surgery.

Comparison of three porpoises (Tursiops truncatus and Lagenorhynchus obliquidens) given nitrous oxide with 18 given halothane, with complete documentation of reflexes and comprehensive physiological monitoring, showed halothane to be a suitable anesthetic for major surgery while nitrous oxide was found to be inadequate. In addition, sodium thiopental administered intravenously was successfully used to facilitate intubation procedures. This development eliminated the need to intubate awake porpoises.

Blood oxygen and ecology of porpoises of three genera.

Blood volumes, hemoglobin concentrations, packed-cell volumes, and heart weights were determined in three genera of propoises which differ from one another in behavior and ecology. The estimate for the total blood-oxygen content of the highly active, deep-diving, pelagic species Phocoenoides dalli was almost three times greater than that for the coastaldwelling species Tursiops truncatus, and about 70 percent greater than for the less active pelagic species, Lagenorhynchus obliquidens. Heart weights of Phocoenoides dalli were about 140 percent greater than in Tursiops truncatus and 55 percent greater than in Logenorhynchus obliquidens.

Galilean satellites: identification of water frost.

Water frost absorptions have been detected in the infrared reflectivities of Jupiter's Galilean satellites JII (Europa) and JIII (Ganymede). We have determined the percentage of frost-covered surface area to be 50 to 100 percent for JII, 20 to 65 percent for JIII, and possibly 5 to 25 percent for JIV (Callisto). The leading side of JIII has 20 percent more frost cover than the trailing side, which explains the visible geometric albedo differences between the two sides. The reflectivity of the material underlying the frost on JII, JIII, and JIV resembles that of silicates. The surface of JI (Io) may be covered by frost particles much smaller than those on JII and JIII.

Sleep and cardiac rhythm in the gray seal.

Telemetric studies of electroencephalograms, electrocardiograms, and electroculograms and concurrent observations of behavior revealed that seals can sleep underwater, on the surface, or while hauled out. Rapid eye movement preceded slow wave sleep and was accompanied by increased respiratory rate and rhythmic tachycardia. While slow wave sleep occurred under all sleep conditions, rapid eye movement occurred only when a seal was hanging at the water surface or hauled out, never underwater.

Morphology and evolutionary biology of the dolphin (Delphinus sp.) brain--MR imaging and conventional histology.

Whole brains of the common dolphin (Delphinus delphis) were studied using magnetic resonance imaging (MRI) in parallel with conventional histology. One formalin-fixed brain was documented with a Siemens Trio Magnetic Resonance scanner and compared to three other brains which were embedded in celloidin, sectioned in the three main planes and stained for cells and fibers. The brain of the common dolphin is large, with the telencephalic hemispheres dominating the brain stem. The neocortex is voluminous and the cortical grey matter thin but extremely extended and densely convoluted. There is no olfactory ventricular recess due to the lack of an anterior olfactory system (olfactory bulb and peduncle). No occipital lobe of the telencephalic hemisphere and no posterior horn of the lateral ventricle are present. A pineal organ could not be detected. The brain stem is thick and underlies a very large cerebellum. The hippocampus and mammillary body are small and the fornix is thin; in contrast, the amygdaloid complex is large and the cortex of the limbic lobe is extended. The visual system is well developed but exceeded by the robust auditory system; for example, the inferior colliculus is several times larger than the superior colliculus. Other impressive structures in the brainstem are the peculiar elliptic nucleus, inferior olive, and in the cerebellum the huge paraflocculus and the very large posterior interpositus nucleus. There is good correspondence between MR scans and histological sections. Most of the brain characteristics can be interpreted as morphological correlates to the successful expansion of this species in the marine environment, which was characterized by the development of a powerful sonar system for localization, communication, and acousticomotor navigation.

Neuron numbers in sensory cortices of five delphinids compared to a physeterid, the pygmy sperm whale.

With its large mass and enormous gyrification, the neocortex of whales and dolphins has always been a challenge to neurobiologists. Here we analyse the relationship between neuron number per cortical unit in three different sensory areas and brain mass in six different toothed whale species, five delphinids and one physeterid. Cortex samples, including primary cortical areas of the auditory, visual, and somatosensory systems were taken from both hemispheres of brains fixed in 10% buffered formalin. The samples were embedded in paraffin, sectioned at 25 microm thickness and stained with cresyl violet. Because cortical thickness varies among toothed whale species, cell counts were done in cortical units measuring 150mum in width, 25 microm in thickness, and extending from the pial surface to the white matter. By arranging the delphinid brains according to their total mass, 834-6052 g, we found decreasing neuron numbers in the investigated areas with increasing brain mass. The pigmy sperm whale (Kogia breviceps), a physeterid with an adult brain weight of 1000 g had a distinctly lower neuron number per cortical unit. As had been expected, an increase in adult brain weight in delphinid cetaceans (family Delphinidae) is not correlated with an increase in neuron number per cortical unit.

Antitumor activity of S-(p-bromobenzyl)glutathione diesters in vitro: a structure-activity study.

S-(p-Bromobenzyl)glutathione is a competitive inhibitor of human glyoxalase I which is part of the cytosolic glyoxalase system. It may be delivered into the cystosol of cells by diesterification wherein it is deesterified by cytosolic nonspecific esterases. S-(p-Bromobenzyl)glutathione diesters had antitumor activity in vitro and in vivo. The inhibition of human leukemia 60 cell growth in vitro by a series of alkyl and cycloalkyl diesters of S-(p-bromobenzyl)glutathione was investigated. For n-alkyl diesters, the n-propyl diester was the most potent derivative with a median growth inhibitory concentration GC50 value of 7.77 +/- 0.01 microM (N = 18). The most potent derivative was S-(p-bromobenzyl)glutathione cyclopentyl diester which had a GC50 value of 4.23 +/- 0.01 microM (N = 21) and also had antitumor activity in vivo.