Evolution of the Sweetness Receptor in Primates. II. Gustatory Responses of Non-human Primates to Nine Compounds Known to be Sweet in Man

The gustatory responses of nine compounds, namely glycine, D-phenylalanine, D-tryptophan, cyanosuosan, magapame, sucrononate, campame, cyclamate and superaspartame, all known as sweet in man, were studied in 41 species or subspecies of non-human primates, selected among Prosimii (Lemuridae and Lorisidae), Platyrrhini (Callitrichidae and Cebidae) and Catarrhini (Cercopithecidae, Hylobatidae and Pongidae). The first six compounds are generally sweet to all primates, which implies that they interact with the primate sweetness receptors essentially through constant recognition sites. Campame is sweet only to Cebidae and Catarrhini, cyclamate only to Catarrhini, superaspartame principally to Callitrichidae and Catarrhini, which implies that all these compounds interact with the receptors partly through variable recognition sites. From the present work, from other previous results (where notably it was observed that alitame is sweet to all primates, ampame only to Prosimii and Catarrhini, and aspartame only to Catarrhini), and from the multipoint attachment (MPA) theory of sweetness reception (as elaborated by Nofre and Tinti from a detailed study of structure-activity relationships of various sweeteners in man), it is inferred that the primate sweetness receptors are very likely made up of eight recognition sites, of which the first, second, third, fourth, seventh and eighth are constant, and the fifth and sixth variable. From these results and from the MPA theory, it is also inferred that the recognition sites of the primate sweetness receptors could be: Asp-1 or Glu-1, Lys-2, Asp-3 or Glu-3, Thr-4, X-5, X-6, Thr-7, Ser-8, where the variable recognition sites X-5 and X-6 would be: Ala-5 and Ala-6 for Callitrichidae, Ser-5 and Ala-6 for Cebidae, Ala-5 and Thr-6 for Prosimii, and Thr-5 and Thr-6 for Catarrhini. By using Tupaiidae (tree shrews) as a reference outgroup and by means of other structural and functional molecular considerations, it appears that Callitrichidae have retained the most primitive receptor among the four types of primate receptors. The possible taxonomic and phylogenetic implications of these findings are discussed. Chem. Senses 21: 747-762, 199

Exploitation of drainage water heat: A novel solution experimented at the Brenner Base Tunnel

Deep tunnels in permeable fractured rock-masses and under high piezometric levels can drain notable volumes of warm water, which are collected under gravity in specific conduits towards the portals, where heat can be exploited. The utilization of this energy source is generally narrowed by the limited presence of end-users near the portals, while other promising heating and cooling needs can be found directly along the tunnel length. The work presents the design, construction and installation of a geothermal system prototype exploiting the drainage water heat directly inside the tunnel. The prototype was named Smart Flowing due to the peculiarity of its heat exchange process. The system was realized and installed inside the exploratory tunnel of the Brenner Base Tunnel, near the border between Italy and Austria. The Smart Flowing modules were built outside and later moved inside the tunnel, where they were placed and assembled concurrently to the advancement of the Tunnel Boring Machine. A design procedure was proposed and validated against a testing and monitoring campaign. The data from the experimental activity confirmed that the drainage water flow guarantees long-term stabilization of circulating water temperature and fast heat recovery afterwards, thus securing the considerable power and performance values of a water-water heat pump connected to the system. A sensitivity analysis allowed the reproduction of different working scenarios, in order to generalize the application of Smart Flowing beyond the specific installation context

VLBA images of High Frequency Peakers

We propose a morphological classification based on the parsec scale structure of fifty-one High Frequency Peakers (HFPs) from the ``bright'' HFP sample. VLBA images at two adjacent frequencies (chosen among 8.4, 15.3, 22.2 and 43.2 GHz) have been used to investigate the morphological properties of the HFPs in the optically thin part of their spectrum. We confirm that there is quite a clear distinction between the pc-scale radio structure of galaxies and quasars: the 78% of the galaxies show a ``Double/Triple'' morphology, typical of Compact Symmetric Objects (CSOs), while the 87% of the quasars are characterised by Core-Jet or unresolved structure. This suggests that most HFP candidates identified with quasars are likely blazar objects in which a flaring self-absorbed component at the jet base was outshining the remainder of the source at the time of the selection based on the spectral shape. Among the sources classified as CSOs or candidates it is possible to find extremely young radio sources with ages of about 100 years or even less.Comment: 21 pages, 8 figures; accepted for pubblication in A&A. Paper version with full resolution images is available at http://www.ira.inaf.it/~ddallaca/orienti.p

Proper motion and apparent contraction in J0650+6001

We present a multi-epoch and multi-frequency VLBI study of the compact radio source J0650+6001. In VLBI images the source is resolved into three components. The central component shows a flat spectrum, suggesting the presence of the core, while the two outer regions, with a steeper spectral index, display a highly asymmetric flux density. The time baseline of the observations considered to derive the source expansion covers about 15 years. During this time interval, the distance between the two outer components has increased by 0.28+/-0.13 mas, that corresponds to an apparent separation velocity of 0.39c+/-0.18c and a kinematic age of 360+/-170 years. On the other hand, a multi-epoch monitoring of the separation between the central and the southern components points out an apparent contraction of about 0.29+/-0.02 mas, corresponding to an apparent contraction velocity of 0.37c+/-0.02c. Assuming that the radio structure is intrinsically symmetric, the high flux density ratio between the outer components can be explained in terms of Doppler beaming effects where the mildly relativistic jets are separating with an intrinsic velocity of 0.43c+/-0.04c at an angle between 12 and 28 degrees to the line of sight. In this context, the apparent contraction may be interpreted as a knot in the jet that is moving towards the southern component with an intrinsic velocity of 0.66c+/-0.03c, and its flux density is boosted by a Doppler factor of 2.0.Comment: 7 pages, 5 pages. Accepted for publication in MNRA

Constraining the nature of High Frequency Peakers. I. The spectral variability

We investigate the spectral characteristics of 51 candidate High Frequency Peakers (HFPs), from the ``bright'' HFP sample, in order to determine the nature of each object, and to obtain a smaller sample of genuine young radio sources. Simultaneous multi-frequency VLA observations carried out at various epochs have been used to detect flux density and spectral shape variability in order to pinpoint contaminant objects, since young radio sources are not expected to be significantly variable on such a short time-scale. From the analysis of the spectral variability we find 13 contaminant objects, 11 quasars, 1 BL Lac, and 1 unidentified object, which we have rejected from the sample of candidate young radio sources. The 6 years elapsed between the first and latest observing run are not enough to detect any substantial evolution of the overall spectrum of genuine, non variable, young radio sources. If we also consider the pc-scale information, we find that the total radio spectrum we observe is the result of the superposition of the spectra of different regions (lobes, hot-spots, core, jets), instead of a single homogeneous radio component. This indicates that the radio source structure plays a relevant role in determining the spectral shape also in the rather common case in which the morphology appears unresolved even on high-resolution scales.Comment: 14 pages, 3 figures; accepted for pubblication in A&

Spectral variability in faint high frequency peakers

We present the analysis of simultaneous multi-frequency Very Large Array (VLA) observations of 57 out of 61 sources from the ``faint'' high frequency peaker (HFP) sample carried out in various epochs. Sloan Digital Sky Survey (SDSS) data have been used to identify the optical counterpart of each radio source. From the analysis of the multi-epoch spectra we find that 24 sources do not show evidence of spectral variability, while 12 objects do not possess a peaked spectrum anymore at least in one of the observing epochs. Among the remaining 21 sources showing some degree of variability, we find that in 8 objects the spectral properties change consistently with the expectation for a radio source undergoing adiabatic expansion. The comparison between the variability and the optical identification suggests that the majority of radio sources hosted in galaxies likely represent the young radio source population, whereas the majority of those associated with quasars are part of a different population similar to flat-spectrum objects, which possess peaked spectra during short intervals of their life, as found in other samples of high-frequency peaking objects. The analysis of the optical images from the SDSS points out the presence of companions around 6 HFP hosted in galaxies, suggesting that young radio sources resides in groups.Comment: 16 pages, 5 figures; accepted for publication in MNRA

Geoarchaeological Evidence of Middle-Age Tsunamis at Stromboli and Consequences for the Tsunami Hazard in the Southern Tyrrhenian Sea

Large-scale landslides at volcanic islands are one of the most dangerous geological phenomena, able to generate tsunamis whose effects can propagate far from the source. However, related deposits are scarcely preserved on-land in the geologic records, and are often difficult to be interpreted. Here we show the discovery of three unprecedented well-preserved tsunami deposits related to repeated flank collapses of the volcanic island of Stromboli (Southern Italy) occurred during the Late Middle Ages. Based on carbon datings, on stratigraphic, volcanological and archaeological evidence, we link the oldest, highest-magnitude investigated tsunami to the following rapid abandonment of the island which was inhabited at that time, contrary than previously thought. The destructive power of this event is also possibly related to a huge marine storm that devastated the ports of Naples in 1343 (200\u2009km north of Stromboli) described by the famous writer Petrarch. The portrayed devastation can be potentially attributed to the arrival of multiple tsunami waves generated by a major landslide in Stromboli island, confirming the hypothetical hazard of these phenomena at a regional scale

Parsec-scale morphology and spectral index distribution in faint high frequency peakers

We investigate the parsec-scale structure of 17 high frequency peaking radio sources from the faint HFP sample. VLBA observations were carried out at two adjacent frequencies, 8.4 and 15.3 GHz, both in the optically-thin part of the spectrum, to obtain the spectral index information. We found that 64% of the sources are resolved into subcomponents, while 36% are unresolved even at the highest frequency. Among the resolved sources, 7 have a morphology and a spectral index distribution typical of young radio sources, while in other 4 sources, all optically associated with quasars, the radio properties resemble those of the blazar population. The equipartition magnetic field of the single components are a few tens milliGauss, similar to the values found in the hotspots of young sources with larger sizes. Such high magnetic fields cause severe radiative losses, precluding the formation of extended lobe structures emitting at centimeter wavelengths. The magnetic fields derived in the various components of individual source are usually very different, indicating a non self-similar source evolution, at least during the very first stages of the source growth.Comment: 14 pages, 5 figures, accepted for publication in MNRA

The tsunamigenic potential of landslide-generated tsunamis on the Vavilov seamount

The investigation of submarine volcanoes and the tsunamigenic potential of possible movements on their flanks is arduous. In most cases, the lack of specific information about the eruptions’ history and their consequences does not allow a comprehensive analysis in terms of hazard. Nevertheless, useful clues on the possible occurrence of mass movements on seamounts can be obtained from a series of research fields. These account for morphological studies, observations of hydrothermal activity, collection of geophysical data (for example, detailed DEM, seismic profiles, magnetic data), etc. In this context, this study presents new bathymetric data of the Vavilov submarine volcano (Tyrrhenian Sea, Italy) and a detailed morphological analysis of the structure. The latter allows the identification of zones potentially prone to mass movements and the development of numerical scenarios to investigate the tsunami potential associated to these movements on the Vavilov flanks. Results prove that the waves generated by the mass displacements in the proposed scenarios (involving sliding volumes between 0.32 km3 and 1.7 km3) reach maximum values in the order of centimetres, not considering dispersive effects. Eventually, a scenario involving the partial collapse of the west flank of the Vavilov Seamount is simulated, although the occurrence of such an event in the past is still debated due to the uncertainties related to the origin and development of the volcano dome. In this scenario, water elevation as high as 10 m are found in large portions of the Tyrrhenian coasts: waves are large enough to emplace sizeable tsunami deposits onshore, that could have been preserved until today in some specific stretches of the coast and could be detected by a finalised geological search. This study belongs to a series of works devoted to the submarine structures of the Tyrrhenian Sea aiming to disclose the tsunamigenic potential of submarine mass movements on their flanks