1,677 research outputs found
Piezospectroscopic measurement of high-frequency vibrations in a pulse-tube cryostat
Vibrations in cryocoolers are a recurrent concern to the end user. They
appear in different parts of the acoustic spectrum depending on the
refrigerator type, Gifford McMahon or pulse-tube, and with a variable coupling
strength to the physical system under interest. Here, we use the
piezospectroscopic effect in rare-earth doped crystals at low temperature as a
high resolution, contact-less probe for the vibrations. With this optical
spectroscopic technique, we obtain and analyze the vibration spectrum up to
700kHz of a 2kW pulse-tube cooler. We attempt an absolute calibration based on
known experimental parameters to make our method partially quantitative and to
provide a possible comparison with other well-established techniques
Optical memory bandwidth and multiplexing capacity in the erbium telecommunication window
We study the bandwidth and multiplexing capacity of an erbium-doped optical
memory for quantum storage purposes. We concentrate on the protocol ROSE
(Revival of a Silenced Echo) because it has the largest potential multiplexing
capacity. Our analysis is applicable to other protocols that involve strong
optical excitation. We show that the memory performance is limited by
instantaneous spectral diffusion and we describe how this effect can be
minimised to achieve optimal performance
New early Eocene vertebrate assemblage from western India reveals a mixed fauna of European and Gondwana affinities
AbstractThe Ypresian Cambay Shale Formation at Vastan and Mangrol lignite mines in Gujarat, western India, has yielded a rich vertebrate fauna with numerous taxa of European affinities. Here we report a new, approximately contemporary vertebrate assemblage from two fossiliferous layers in the nearby mine of Tadkeshwar. These layers have yielded a similar mammal fauna with the co-occurrence of the perissodactyl-like cambaytheriid Cambaytherium thewissi, the adapoid primates Marcgodinotius indicus and cf. Asiadapis cambayensis, and the hyaenodontid Indohyaenodon raoi. The presence of these species in both Vastan and Tadkeshwar mines and at different levels suggests that the deposits between the two major lignite seams represent a single land mammal age. Apart from the aforementioned species there is a new, smaller species of Cambaytherium, and a new genus and species of esthonychid tillodont. This fauna also contains the first large early Eocene vertebrates from India, including an unidentified Coryphodon-like pantodont, a dyrosaurid crocodyliform and a new giant madtsoiid snake. Among the Tadkeshwar vertebrates several taxa are of Gondwana affinities, such as Pelomedusoides turtles, dyrosaurids, and large madtsoiids, attesting that the early Eocene was a crucial period in India during which Laurasian taxa of European affinities co-existed with relict taxa from Gondwana before the India-Asia collision. Our results suggest that terrestrial faunas could have dispersed to or from Europe during episodes of contact between the Indian subcontinent and different island blocks along the northern margin of the Neotethys, such as the Kohistan–Ladakh island-arc system. Gondwana taxa might represent remnants of ghost lineages shared with Madagascar, which reached the Indian subcontinent during the late Cretaceous; alternatively they might have come from North Africa and passed along the southern margin of the Neotethys to reach the Indian subcontinent. These dispersals would have been possible as a result of favourable paleogeographic conditions such as the particular Neotethys conformation during the beginning of the early Eocene
Methicillin-Resistant Staphylococcus aureus Among Younger Population in Northeastern Ohio
Author Institution: Department of Biological Sciences, Kent State UniversityAuthor Institution: College of Nursing, Kent State UniversityAuthor Institution: Infection Control, Ashtabula County Medical CenterThe Ashtabula County Medical Center (ACMC), a 241-bed medical center in Ashtabula County, Ohio, has been providing inpatient and outpatient services for a portion of Northeastern Ohio for over a century. In the current report, we have investigated the rate of Methicillin-resistant Staphylococcus aureus (MRSA) occurrence among the younger population (less than 25 years of age) who sought medical attention at ACMC emergency room or one of its outpatient-affiliates (e.g. physician’s office or clinics) from January 2006 to December 2007. Here, we report a significant increase in incidence of MRSA among patients
six to 25 years of age during this time period. Considering the age population and the origin of specimens, the present findings suggest a rapid increase in incidence of MRSA among the general population in Northeastern Ohio. These findings demonstrate the need for the development of new protocols aimed at identifying preventive measures in order to immobilize the spread of such pathogens among the younger population in the region
A New Adapoid Primate From The Early Eocene Of India
http://deepblue.lib.umich.edu/bitstream/2027.42/57497/1/Vol 31 No 14 final 12-19-07.pd
Aspect traumatogène de l’exclusion sociale, une analyse enthnopsychanalytique
International audienceThis research explores the phenomenon of social exclusion into a complementarist approach using interviews with six people as a starting point. Thanks to a qualitative method based on the grounded theory, we carried out a comparative analysis of our material. The analysis helped to show the traumatogenic dimension of social exclusion. We used the concept of liminality from the cultural anthropologist Victor Turner, in order to describe the destabilizing aspect of this experience, but also its potential to provoque profound change. The traumatogenic dimension appears in each story, butsometimes it provoques a real “initiatory transformation”. In other cases it may lead to defensive psychic arrangements which are constructed on the basis of a splitting between the “sacred" and the “profane” and even really become traumatic.Cette recherche explore le phénomène d’exclusion sociale dans une approche complémentariste en partant d’entretiens effectués avec six personnes. Grâce à une méthode qualitative basée sur la grounded theory, nous avons réalisé une analyse comparative de différentes parties de notre matériel. Nous avons mis en évidence la dimension traumatogène de l’exclusion sociale. La notion de liminalité de l’anthropologue Victor Turner nous a permis de décrire le potentiel déstabilisant de cette expérience, tout autant que sa capacité de «métamorphose » : si la dimension traumatogène est présente dans chacun des récits, la situation d’exclusion sociale peut, dans certains cas, prendre la forme d’une véritable « transformation initiatique ». Pour d’autres, elle peut aussi amener à des aménagements défensifs construits sur un clivage entre le « sacré » et le « profane », ou encore devenir véritablement traumatique
First tillodont from India: additional evidence for an early Eocene faunal connection between Europe and India?
Vastan LigniteMine in southeastern Gujarat, India, produces the oldest known Cenozoic land-mammals and the only early Eocene continental vertebrate fauna known from India (e.g., Bajpai et al. 2005; Rana et al. 2005, 2008; Rose et al. 2006, 2008, 2009; Smith et al. 2007; Rage et al. 2008). The fauna co- mes from the Cambay Shale Formation and has been dated as middle Ypresian (~52Ma, early Cuisian) based on a common nummulitid foraminiferan from about 15 m above the verte- brate-producing layer (Sahni et al. 2006; Rana et al. 2008). However, a recent study of dinoflagellate cysts from the sec- tion suggests that the deposits may be as old as 54-55 Ma (Garg et al. 2008). Although some elements of the fauna, such as anthracobunids and lagomorphs, have Asian affinities, a surprising number of taxa among the snakes, bats, insecti- vores, primates, rodents, and artiodactyls appear to be most closely related to early Eocene European or North American taxa. This may simply reflect the poor state of knowledge of contemporary south Asian vertebrate faunas; alternatively, it might be evidence of previously unsuspected early Eocene faunal exchange between Europe and southwest Asia.We report here two teeth of a tillodont from Vastan Mine, which constitute the first record of the mammalian order Tillodontia known from India. Despite the much greater generic diversity of tillodonts inAsia than elsewhere, theVastan tillodont shows clear affinities with Euramerican esthonychines
An ailuravine rodent from the lower Eocene Cambay Formation at Vastan, Western India, and its palaeobiogeographic implications
A new ailuravine rodent, Meldimys musak sp. nov. (Mammalia: Rodentia, Ischyromyidae), is recorded from the lower Eocene lignites of western India. It is the oldest record of Rodentia from India. M. musak is more derived than the earliest Eocene ailuravine Euromys cardosoi from Portugal and more generalized than late early Eocene E. inexpectatus and Ailuravus michauxi from France. Its dental morphology closely corresponds to the middle early Eocene species M. louisi, which lived about 52 Ma in Western Europe. Meldimys was previously known only from Europe, and ailuravines were previously reported only from Europe and North America. Its occurrence in India allows the first direct correlation between the early Eocene land mammal horizons of Europe and India, and raises the possibility of a terrestrial faunal exchange between India and Eurasia close to the Palaeocene-Eocene transition
A novel archaeal regulatory protein, Sta1, activates transcription from viral promoters
While studying gene expression of the rudivirus SIRV1 in cells of its host, the hyperthermophilic crenarchaeon Sulfolobus, a novel archaeal transcriptional regulator was isolated. The 14 kDa protein, termed Sulfolobus transcription activator 1, Sta1, is encoded on the host chromosome. Its activating effect on transcription initiation from viral promoters was demonstrated in in vitro transcription experiments using a reconstituted host system containing the RNA polymerase, TATA-binding protein (TBP) and transcription factor B (TFB). Most pronounced activation was observed at low concentrations of either of the two transcription factors, TBP or TFB. Sta1 was able to bind viral promoters independently of any component of the host pre-initiation complex. Two binding sites were revealed by footprinting, one located in the core promoter region and the second ∼30 bp upstream of it. Comparative modeling, NMR and circular dichroism of Sta1 indicated that the protein contained a winged helix–turn–helix motif, most probably involved in DNA binding. This strategy of the archaeal virus to co-opt a host cell regulator to promote transcription of its genes resembles eukaryal virus–host relationships
Molecular Basis of Inward Rectification: Polyamine Interaction Sites Located by Combined Channel and Ligand Mutagenesis
Polyamines cause inward rectification of (Kir) K+ channels, but the mechanism is controversial. We employed scanning mutagenesis of Kir6.2, and a structural series of blocking diamines, to combinatorially examine the role of both channel and blocker charges. We find that introduced glutamates at any pore-facing residue in the inner cavity, up to and including the entrance to the selectivity filter, can confer strong rectification. As these negative charges are moved higher (toward the selectivity filter), or lower (toward the cytoplasm), they preferentially enhance the potency of block by shorter, or longer, diamines, respectively. MTSEA+ modification of engineered cysteines in the inner cavity reduces rectification, but modification below the inner cavity slows spermine entry and exit, without changing steady-state rectification. The data provide a coherent explanation of classical strong rectification as the result of polyamine block in the inner cavity and selectivity filter
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