233 research outputs found
Geological Controls in the Development of Caves in the South-Central Ozarks of Missouri, USA
Področje Ozarkov v Missouriju je eden največjih kraških terenov v ZDA. Prevladujočo litologijo predstavljajo kambrijski in ordovicijski dolomiti in peščenjaki. Številne, večinoma horizontalne jame in veliki kraški izviri so značilnosti krasa Ozarkov. Od oktobra 1996 do vključno maja 1999 smo obiskali 23 kraških jam, za 18 jam v osrednjem delu južnih Ozarkov smo naredili geološke karte. Za ta članek smo predstavili geologijo štirih jam. Prevladujoča geološka zakonitost, ki vpliva na oblikovanje jam je vpad plasti in preferenčna plast stromatolitnega dolomita. Edina možna povezava med geološko strukturo in smerjo jamskih rovov je smer rovov sever-jug in smer razpok sever-jug.The Ozark Plateaus Province of Missouri is one of the largest karst areas in the USA. The dominant lithology is Cambrian and Ordovician dolomite and sandstone. Numerous, mostly horizontal caves and large springs are characteristic of Ozark karst. From October 1996 through May 1999, 23 caves were visited and geologic maps were made for 18 caves in the Ozarks of south-central Missouri. For this paper, the geology of four of the caves is discussed. The prevailing geologic control on cave development is bedding plane dip and preferred strata-a stromatolitic dolomite bed. The only recognized relationship between geologic structure and cave passage trends is the correlation of a N-S trend of cave passages to a general N-S trend in joints
Stable and unstable regimes in Bose-Fermi mixture with attraction between components
A collapse of the trapped boson- fermion mixture with the attraction between
bosons and fermions is investigated in the framework of the effective
Hamiltonian for the Bose system. The properties of the Rb and K
mixture are analyzed quantitatively at . We find numerically solutions of
modified Gross- Pitaevskii equation which continuously go from stable to
unstable branch. We discuss the relation of the onset of collapse with
macroscopic properties of the system. A comparison with the case of a Bose
condensate of atomic system is given.Comment: 7 pages, 5 figure
Bats of Skydusky Hollow, Bland County, Virginia
During the period 22 November 1999 – 11 October 2001, winter hibernacula surveys, spring staging/autumn swarming surveys, and summer surveys for bats were completed in caves of Skydusky Hollow, Bland County, Virginia. During winter, 12 caves were entered and 16,185 bats counted: 235 Myotis sodalis (Indiana bat), 14,475 Myotis lucifugus (little brown myotis), 12 Myotis septentrionalis (northern myotis), 7 Myotis leibii (eastern small-footed myotis), 1,441 Pipistrellus subflavus (eastern pipistrelle), and 15 Eptesicus fuscus (big brown bat). Myotis sodalis hibernated in thermally stable areas of 7 -9 ̊C. The largest concentration of M. lucifugus (n = 4,280) hibernated in an area that was cooler (6.5 ̊C) than areas used by M. sodalis. The remaining 6,300 M. lucifugus hibernated at temperatures similar to, or slightly cooler than, temperatures used by M. sodalis. Intra-cave (and possibly inter-cave) movements of M. lucifugus and M. sodalis during the season of hibernation concentrated bats in cooler areas of the caves. An unusually large concentration of P. subflavus (n = 920) hibernated in Coon Cave in a warm (8.6 – 9.7 ̊C, stable environment. Proportions of species of bats captured during spring staging and autumn swarming varied from proportions found during winter hibernation. Mating and perhaps other social functions affect patterns of autumn use. No concentration of bats used the caves during summer
Extrauterine listeriosis in the gravid mouse influences embryonic growth and development
Gravid mice and other rodents inoculated with Listeria monocytogenes typically fail to clear an intrauterine infection and either succumb or expel their intrauterine contents. We took advantage of this property to investigate the effects of an extrauterine infection on parameters of pregnancy success. Pregnant mice were selected for our study if they showed no clinical signs of listeriosis following oral inoculation at 7.5 gestational days (gd), and had no detectable intrauterine colony forming units (cfu) at near term (18.5 gd). The range of oral doses employed was 10(6)-10(8) cfu per mouse for two listerial serotype strains (4nonb and 1/2a). At all doses, inoculation resulted in a decrease in average near-term (18.5 gd) fetal weight per litter compared to sham inoculated controls. Additionally, embryonic death (indicated by intrauterine resorptions) was exhibited by some inoculated mice but was absent in all sham inoculated animals. In parallel experiments designed to detect possible loss of placental function, gravid uteruses were examined histopathologically and microbiologically 96 h after oral inoculation. Placental lesions were associated with high (> 10(6)), but not low (< 10(2)) or absent intrauterine cfu. In vitro, mouse embryonic trophoblasts were indistinguishable from mouse enterocytes in terms of their sensitivity to listerial exposure. A model consistent with our observations is one in which products (host or bacterial) generated during an acute infection enter embryos transplacentally and influences embryonic survival and slows normal growth in utero
Prime Focus Spectrograph - Subaru's future -
The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and
Redshifts (SuMIRe) project has been endorsed by Japanese community as one of
the main future instruments of the Subaru 8.2-meter telescope at Mauna Kea,
Hawaii. This optical/near-infrared multi-fiber spectrograph targets cosmology
with galaxy surveys, Galactic archaeology, and studies of galaxy/AGN evolution.
Taking advantage of Subaru's wide field of view, which is further extended with
the recently completed Wide Field Corrector, PFS will enable us to carry out
multi-fiber spectroscopy of 2400 targets within 1.3 degree diameter. A
microlens is attached at each fiber entrance for F-ratio transformation into a
larger one so that difficulties of spectrograph design are eased. Fibers are
accurately placed onto target positions by positioners, each of which consists
of two stages of piezo-electric rotary motors, through iterations by using
back-illuminated fiber position measurements with a wide-field metrology
camera. Fibers then carry light to a set of four identical fast-Schmidt
spectrographs with three color arms each: the wavelength ranges from 0.38
{\mu}m to 1.3 {\mu}m will be simultaneously observed with an average resolving
power of 3000. Before and during the era of extremely large telescopes, PFS
will provide the unique capability of obtaining spectra of 2400
cosmological/astrophysical targets simultaneously with an 8-10 meter class
telescope. The PFS collaboration, led by IPMU, consists of USP/LNA in Brazil,
Caltech/JPL, Princeton, & JHU in USA, LAM in France, ASIAA in Taiwan, and
NAOJ/Subaru.Comment: 13 pages, 11 figures, submitted to "Ground-based and Airborne
Instrumentation for Astronomy IV, Ian S. McLean, Suzanne K. Ramsay, Hideki
Takami, Editors, Proc. SPIE 8446 (2012)
Prime Focus Spectrograph (PFS) for the Subaru Telescope: Overview, recent progress, and future perspectives
PFS (Prime Focus Spectrograph), a next generation facility instrument on the
8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed,
optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394
reconfigurable fibers will be distributed over the 1.3 deg field of view. The
spectrograph has been designed with 3 arms of blue, red, and near-infrared
cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure
at a resolution of ~1.6-2.7A. An international collaboration is developing this
instrument under the initiative of Kavli IPMU. The project is now going into
the construction phase aiming at undertaking system integration in 2017-2018
and subsequently carrying out engineering operations in 2018-2019. This article
gives an overview of the instrument, current project status and future paths
forward.Comment: 17 pages, 10 figures. Proceeding of SPIE Astronomical Telescopes and
Instrumentation 201
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