1,238 research outputs found
Do domestic dogs learn words based on humansâ referential behaviour?
Some domestic dogs learn to comprehend human words, although the nature and basis of this learning is unknown. In the studies presented here we investigated whether dogs learn words through an understanding of referential actions by humans rather than simple association. In three studies, each modelled on a study conducted with human infants, we confronted four word-experienced dogs with situations involving no spatial-temporal contiguity between the word and the referent; the only available cues were referential actions displaced in time from exposure to their referents. We found that no dogs were able to reliably link an object with a label based on social-pragmatic cues alone in all the tests. However, one dog did show skills in some tests, possibly indicating an ability to learn based on social-pragmatic cues
Using an InGrid Detector to Search for Solar Chameleons with CAST
We report on the construction, operation experience, and preliminary
background measurements of an InGrid detector, i.e. a MicroMegas detector with
CMOS pixel readout. The detector was mounted in the focal plane of the Abrixas
X-Ray telescope at the CAST experiment at CERN. The detector is sensitive to
soft X-Rays in a broad energy range (0.3--10 keV) and thus enables the search
for solar chameleons. Smooth detector operation during CAST data taking in
autumn 2014 has been achieved. Preliminary analysis of background data
indicates a background rate of above 2 keV and
around
1 keV. An expected limit of on the
chameleon photon coupling is estimated in case of absence of an excess in solar
tracking data. We also discuss the prospects for future operation of the
detector.Comment: Contributed to the 11th Patras Workshop on Axions, WIMPs and WISPs,
Zaragoza, June 22 to 26, 201
Autodocking Studies of Oxygenated Fullerenes as Inhibitors of The HIV Protease
In a previous study, several oxygenated fullerene compounds were produced by ozonation of C60 (Buckminsterfullerene) and were identified by elemental analysis and by SALI (surface analysis by laser ionization). Some of these compounds, especially a batch, SK-5, a mixture of C60O1-8, were shown to inhibit activities of HIV-Protease with IC50 (concentration for 50% inhibition) of 1 mg/mol in the in-vitro studies. The oxygenated fullerenes were shown to have epoxide, ketones, and hydroxyl functionalities. As expected, C60 interacted with ozone with alkene functionality and not as an aromatic compound. It was postulated that C60O had epoxide functionality, as a product of ozonation of one of the double bonds of C60; C60O2 had ketone functionalities by Ozonolysis of one of the double bonds of C60; C60O4, C60O6, C60O8 had ketone functionalities by Ozonolysis of successive double bonds of C60. The hydroxyl functionality was likely produced due to interaction of water and the oxygenated fullerenes. In the present study, the interactions of oxygenated fullerenes (small molecules) with HIV-Protease (macromolecules) at the molecular levels were studied via blind docking using AutoDock Vina software to elucidate the mechanism of these interactions. The structures of C60O, C60O2, C60O4, C60O6, C60O8 were generated using Spartan software and were docked with a crystal structure of the HIV-Protease (PR) obtained from The Brookhaven Protein Data Bank using AutoDock Vina. These docking studies showed that the oxygenated fullerenes bound to multiple sites of the HIV-PR with high binding affinities (-10.4 to -8.1 kcal/mol). Nine docking poses were generated for each structure, and the models of each conformation were studied using PyMOL software. The docking models in PyMOL suggest that the high binding affinity is a result of the abundance of strong hydrogen bonds ~2.3⍠long across the various C60OX structures. The presence of dipole-dipole and van der waals interactions were also found to have played a significant role in binding, with several conformations exhibiting strong binding (⼠-9.8 kcal/mol) with no hydrogen bonds. Results indicate a strong correlation between the ability of C60OX to produce hydrogen bonds/strong dipole interaction with the HIV-PR and inhibition efficacy
Donald Davidsonâs Account of Conceptual Schemes as Related to Inter-Lingual Translation
In his address âOn the Very Idea of a Conceptual Scheme,â Donald Davidson puts forth the notion of varying conceptual schemes. The variation makes relative the notions of truth and concept. Davidson argues against varying conceptual schemes via the construction of a system of translation between different languages. I argue that Davidsonâs system, adapted from Tarskiâs Convention T, is inconsistent with the requirements of the formal structure Convention T brings. In particular, it is shown that Davidson fails to uniformly apply his notion of what it means to understand a language. Furthermore, it is shown that Davidsonâs adaptation of Convention T fails to grasp the heart of Convention T: the removal of the Liarâs Paradox. While these problems disappear upon the repeal of one of Davidsonâs assumptions, the cost of the repeal appears to be the loss of a working system
Cenozoic deep-water agglutinated foraminifera in the North Atlantic
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution December 1987Cenozoic (predominantly Paleogene) "flysch-type" agglutinated foraminiferal
assemblages and their modern analogs in the North Atlantic and adjacent
areas have been studied to provide an overview of their spatial and temporal
distribution and utility for paleoenvironmental analysis. Over 200 species of
agglutinated foraminifera have been recognized in Paleogene sediments from
North Atlantic and Tethyan basins. This unified taxonomic data base enables
the first general synthesis of biostratigraphic, paleobiogeographic and
paleobathymetric patterns in flysch-type agglutinated assemblages from upper
Cretaceous to Neogene sediments in the North Atlantic. The majority of taxa
are cosmopolitan, but latitudinal, temporal and depth-related trends in
diversity and species composition are observed among flysch-type assemblages.
Modern deep-sea agglutinated foraminiferal faunas provide an analog to
fossil flysch-type assemblages and serve as models for paleoecologic studies.
Core-top samples from the Panama Basin, Gulf of Mexico and Nova Scotian
continental rise were examined in order to determine the habitats of modern
species of agglutinated foraminifera. The ecology of modern taxa provides
constraints on the paleoenvironmental significance of fossil agglutinated
assemblages in the North Atlantic, and their utility for paleoceanography.
Towards this end, spade core samples from a 3912 m deep station in the
Panama Basin were studied to determine abundance and microhabitat partitioning
among living agglutinated foraminiferal populations and the preservation of
dead assemblages. The genera Dendrophrya, Cribrostomoides and Ammodiscus have
epifaunal habitats and the genus Reophax is predominantly infaunal. Species
of Reophax are probably responsible for fine reticulate burrows observed in xradiographs.
An experiment using recolonization trays in the Panama Basin was
designed to identify opportunistic species of benthic foraminifera, and to
assess the rate at which a population can colonize an abiotic substrate. The
most successful colonizer at this site is Reophax, while Dendrophrya displays
the lowest capability for dispersal. After nine months the abundance of
living individuals in sediment trays was one-tenth to one-third that of background
abundance, but the faunal diversity did not differ greatly from control
samples. Recolonization by benthic foraminifera is more rapid than among
macrofaunal invertebrates.
Modern agglutinated assemblages from the Louisiana continental slope were
examined to determine changes in species composition associated with hydrocarOrganic-
bon seeps. rich substrates are characterized by a decrease in astrorhizids and an increase in trochamminids and textulariids. Highly organicenriched
substrates with chemosynthetic macrofauna are dominated by
Trochammina glabra and Glomospira charoides.
The biostratigraphy of fossil agglutinated foraminifera in the North
Atlantic is based on detailed analysis of 670 samples from 14 wells and one
outcrop section, and examination of additional picked faunal slides from
industry wells. Local biostratigraphic schemes are established for Trinidad,
Northern Spain, the Labrador Sea, Baffin Bay, and the Norwegian-Greenland Sea.
These schemes are compared with existing biostratigraphic frameworks from the
Labrador Margin, the North Sea, and the Polish Carpathians. A number of
species show utility for biostratigraphy in the North Atlantic. Lineages
which contain stratigraphically useful species include the Haplophragmoides
cf. glabra - Reticulophragmium group, Hormosina, and Karreriella.
Significant faunal turnovers are observed at the Paleocene/Eocene, Ypresian/
Lutetian and Eocene/Oligocene boundaries. A reduction in diversity occurs
at the Paleocene/Eocene boundary in all bathyal sections studied, and
agglutinated forminifera disappear entirely from abyssal low-latitude DSDP
sites. In the Gibraltar Arch, the Labrador Sea and the Norwegian-Greenland
Sea, the Ypresian/Lutetian boundary is characterized by a Glomospira-facies.
This is attributed to a rise in the lysocline associated with increased
paleoproductivity and the NP14 sealevel lowstand. The Eocene/Oligocene
boundary is delimited by another major turnover and the last occurrence of a
number of important taxa. At Site 647, where recovery across the
Eocene/Oligocene boundary was continuous, the change from an Eocene
agglutinated assemblage to a predominantly calcareous assemblage in the early
Oligocene took place gradually, over a period of about 4 m.y. The rate of
change of the faunal turnover accelerated near the boundary. This faunal
turnover is attributed to changes in the preservation of agglutinated
foraminifera, since delicate species disappeared first. Increasingly poorer
preservation of agglutinated foraminifera in the late Eocene to earliest
Oligocene reflected the first appearance of cool, nutrient-poor deep water in
the southern Labrador Sea. The approximately coeval disappearance of
agglutinated assemblages along the Labrador Margin was caused by a regional
trend from slope to shelf environments, accentuated by the "mid"-Oligocene
sealevel lowstand.
Paleobiogeographic patterns in flysch-type foraminifera were examined in
the Paleogene of the North Atlantic. In the early Paleogene, general decrease
in diversity is observed from low to high latitudes and from the continental
slope to the deep ocean basins. The diversity of these microfossils declines
in most studied sections throughout the Paleogene. The last common occurrence
(LCO) of flysch-type foraminifera in the North Atlantic exhibits a pattern of
diachrony with latitude and depth. Extinctions occurred first at abyssal
depths and at low latitudes. Agglutinated assemblages disappeared from the
northern Atlantic region in the early Oligocene. However, the deep Norwegian-Greenland
Sea served as a refuge for many species, and agglutinated
assemblages persisted there until the early Pliocene. The LCO of flysch-type
foraminifera may have been related to the transition from a warm, sluggish
deep sea environment to a cooler, more oxygenated, thermohaline-driven deep
circulation pattern caused by bipolar cooling.
The paleobathymetry of Paleogene agglutinated assemblages in the North
Atlantic differs from Cretaceous patterns. Shallow-water assemblages of
Paleogene age contain robust astrorhizids, loftusiids and coarse lituolids,
whereas deep assemblages possess delicate tubular forms, ammodiscids, and
smooth lituolids. At low latitudes, upper bathyal assemblages contain
abundant calcareous ataxophragmiids. Paleocene paleobathymetric patterns in
the North Atlantic compare well with patterns observed in the Carpathian
troughs.
The utility of agglutinated foraminifera in paleoceanography is illustrated
by a study of the paleocommunity structure of fossil assemblages in ODP
Hole 646B on the Eirik Ridge (Labrador Sea). The synecology of benthic foraminifera
in Hole 646B places constraints on the history of Denmark Straits
Overflow Water over that site. Below seismic horizon "R3", a Miocene assemblage
contains smooth agglutinated species with abundant Nuttalides umbonifera,
indicating corrosive bottom water and tranquil conditions. A coarse
agglutinated assemblage with "NADW-type" calcareous benthics is observed above
the seismic horizon. This faunal turnover at horizon "R3" reflects the onset
(or renewal) of significant Denmark Straits overflow at -7.5 Ma. Agglutinated
species disappear between reflector "R2", and the base of the sediment drift,
indicating a change in deep-water properties associated with the re-opening of
the Mediterranean. The onset of drift sedimentation at the Eirik Ridge is
dated at -4.5 Ma. Drift formation ceased at -2.5 Ma, concomitant with the
appearance of ice-rafted sediments.Financial support for this study was provided through grants from the
Ocean Drilling Program, the Texas A&M Research Foundation/US Scientific
Program (1892-B05), the National Science Foundation through grants OCE-8217586
to J.F. Grassle and OCE 82-17413 to R.B. Whitlatch, the Geological
Society of America (86-3599), the WHOI Education Office, and the Margaret M.
Patterson Memorial Scholarship Fund. The Dean's Office of the Jagiellonian
University provided support during my work with the Grzybowski Collection
The Post-Festo World of Equivalents, 2 J. Marshall Rev. Intell. Prop. L. 182 (2003)
The Supreme Court again began to delve into substantial patent issues by addressing the interplay between prosecution history estoppel and the doctrine of equivalents. An analysis of the opinions in the Federal Circuitâs en banc ruling, together with the Supreme Courtâs own decision may help to clarify some of the unanswered questions still lingering regarding what equivalents are available and when. The prosecution history will take a more prominent place in the minds of both patent prosecutors and litigators as courts attempt to determine the appropriate relationship between prosecution history estoppel and the doctrine of equivalents
An InGrid based Low Energy X-ray Detector
An X-ray detector based on the combination of an integrated Micromegas stage
with a pixel chip has been built in order to be installed at the CERN Axion
Solar Telescope. Due to its high granularity and spatial resolution this
detector allows for a topological background suppression along with a detection
threshold below . Tests at the CAST Detector Lab show the
detector's ability to detect X-ray photons down to an energy as low as
. The first background data taken after the installation at the
CAST experiment underline the detector's performance with an average background
rate of between 2 and
when using a lead shielding.Comment: 4 pages, 5 figures, Contributed to the 10th Patras Workshop on
Axions, WIMPs and WISPs, CERN, June 29 to July 4, 201
Design Optimization of a Boundary Layer Ingestion Propulsion System for a Long-Range, High-Altitude UAV
Recent studies have proposed using Boundary Layer Ingestion propulsion systems utilizing turboelectric generators to increase fuel efficiency in the next generation of airliners. Another aircraft platform where fuel savings would be highly valuable would be long-range UAVs. Therefore, a design optimization study was conducted on a BLI propulsor for an adaptation of a RQ-4 Global Hawk airframe, which is an airframe that is already proven to be ideal for long range missions. The study was performed on STAR CCM+ CFD software, using the Design Manager feature within the program. The interest was in optimizing the propulsor for cruise conditions, when the fuel savings will be most valuable in achieving a longer range. An initial simulation was performed, to act as the reference simulation for the Design Manager study. After initial values were obtained, the Design Manager study was conducted in two different iterations, searching for the ideal design. A variety of geometric variables were input into the Design Manager, such as inlet and outlet cross-sectional area, and the shape of the inner engine. Upon completion of the study, an ideal design of a BLI propulsor was found. The total power necessary to achieve static equilibrium flight was reduced from 222 MW to 193.2 MW, a savings of 12.87%. Such power savings are significant considering that a BLI propulsor already achieves fuel savings compared with a traditional propulsor that ingests air traveling at the free stream velocity. This study acts as a rationale for the further development of a physical scale model to validate such results, and the possibility of commercial development if satisfactory results are obtained
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