99 research outputs found
The Dark Matter Problem in Light of Quantum Gravity
We show how, by considering the cumulative effect of tiny quantum
gravitational fluctuations over very large distances, it may be possible to:
() reconcile nucleosynthesis bounds on the density parameter of the Universe
with the predictions of inflationary cosmology, and () reproduce the
inferred variation of the density parameter with distance. Our calculation can
be interpreted as a computation of the contribution of quantum gravitational
degrees of freedom to the (local) energy density of the Universe.Comment: 13 pages, LaTeX, (3 figues, not included
Use of Extinguish Plusâą to Reduce Red Imported Fire Ants and Increase Northern Bobwhite Abundance
Populations of northern bobwhite (Colinus virginianus) have been declining throughout Texas since at least the 1970s. The red imported fire ant (RIFA, Solenopsis invicta) was introduced from South America and reached Texas by the 1950s. Previous studies have documented the negative effects of RIFA on northern bobwhite populations through both direct predation and indirect reduction of small invertebrates. In 2013, 2014, and 2015, large areas (1,490 ha in 2013 and 2,380 ha in 2014 and 2015) of the 3,744-ha portion of the Attwater Prairie Chicken National Wildlife Refuge (APCNWR) in Colorado County, Texas, were aerially treated with Extinguish Plusâą, a chemical pesticide and reproductive inhibitor that targets ants. Our study took place on APCNWR and our objectives included evaluation of the impacts of RIFA treatment on 1) RIFA abundance, and 2) northern bobwhite nest success and brood survival. We trapped, banded, and radiocollared northern bobwhites in areas treated and not treated with Extinguish Plus from May 2014 through August 2016. We also collected RIFA abundance data using baited Petri dishes on areas treated and nontreated areas during these periods. Treatment reduced RIFA presence on the refuge by 73.4% during 2014 and 2015, but did not reduce RIFA presence during 2016 possibly because of displacement of RIFA colonies due to heavy flooding on the refuge. We detected a difference (Ï21 = 11,009, P = 0.0009) in the number of females sighted with and without broods between treated (19.5% F with broods) and nontreated areas (35.7% F with broods). We also found a difference (t12 = 2.51, P = 0.027) in mean number of chicks per brood sighted within treated (4.7) versus nontreated (9.3) areas for 2014 and 2014; but in 2016, we found no difference (t12 = 0.32, P = 0.754) in mean number of chicks per brood sighted within treated (7.7) and nontreated (8.4) areas, which was possibly due to extensive flooding in the nontreated area in April that destroyed most first nests. Our data suggested treatment with Extinguish Plus did not increase northern bobwhite abundance on the APCNWR during the 2014, 2015, and 2016 bobwhite nesting seasons. Our results differ from previous studies, possibly because of time since treatment and differences in environmental factors between treated and nontreated areas such as ecological site, vegetation composition, and predator abundance
Geophysical structure of the Southern Alps orogen, South Island, New Zealand
The central part of the South Island of New Zealand is a product of the transpressive continental collision of the Pacific and Australian plates during the past 5 million
years, prior to which the plate boundary was largely transcurrent for over 10 My. Subduction occurs at the north (west dipping) and south (east dipping) of South
Island. The deformation is largely accommodated by the ramping up of the Pacific plate over the Australian
plate and near-symmetric mantle shortening. The initial
asymmetric crustal deformation may be the result of an initial difference in lithospheric strength or an
inherited suture resulting from earlier plate motions.
Delamination of the Pacific plate occurs resulting in the uplift and exposure of mid-crustal rocks at the plate boundary fault (Alpine fault) to form a foreland mountain
chain. In addition, an asymmetric crustal root (additional 8 - 17 km) is formed, with an underlying mantle downwarp. The crustal root, which thickens southwards, comprises the delaminated lower crust and a thickened overlying middle crust. Lower crust is variable in thickness along the orogen, which may arise from convergence in and lower lithosphere extrusion along the orogen. Low velocity zones in the crust occur adjacent to the plate boundary (Alpine fault) in the Australian and Pacific plates, where they are attributed to fracturing of the upper crust as a result of flexural bending for the Australian plate and to high pressure fluids in the crust derived from prograde metamorphism of the crustal rocks for the Pacific plate
The Vehicle, Fall 1984
Vol. 26, No. 1
Table of Contents
Thoughts on I-57Jim Caldwellpage 3
A Night Between Lonely and BlindJennifer K. Soulepage 4
What is Unnatural is Sometimes MagicAngelique Jenningspage 4
Cutting ClosenessBecky Lawsonpage 5
PhotoBrian Ormistonpage 6
The Sensuality of Corn One Week in AugustMichelle Mitchellpage 7
American MusicJim Caldwellpage 7
Water is WaitingMichael Kuopage 8
WhereJennifer K. Soulepage 8
The Fishing HoleJan Kowalskipage 9
Miller\u27s PondSue Gradypage 9
PhotoCathy Stonerpage 11
Young Man Reading To His LoverMaggie Kennedypage 11
ShellsChristopher R. Albinpage 12
In The ShadeJohn Fehrmannpage 12
FallLynanne Feilenpage 13
IndecisionDave L. Brydenpage 13
Dark Falls SoftlyAngelique Jenningspage 14
Not a Parked \u2757 Chevy in the Summer in the CountryMichelle Mitchellpage 20
BirdAnnie Heisepage 20
Clouds Created Only For Poets And Certain WomenJennifer K. Soulepage 21
SandGraham Lewispage 22
PhotoFred Zwickypage 23
Judgment CallCathy Moepage 23
I was hip that night Dan Hintzpage 24
A Sight Of WindDan Von Holtenpage 25
Tillard Isabel M. Parrottpage 26
The WidowMaggie Kennedypage 27
The SeparationMichelle Mitchellpage 27
The Garden Hose TrialMaggie Kennedypage 28
InterruptionsJennifer K. Soulepage 28
On Happening Across Jesus While Cleaning the BasementMaggie Kennedypage 29
GileonMichelle Mitchellpage 30
If My Father Were A Writer, He Would Still BuildAngelique Jenningspage 36
A Visit to Grandpa Gib\u27s HouseTammy Veachpage 37
For Having SeenAngelique Jenningspage 38
PhotoJudy Klancicpage 39
The Earth in BlueSusan J. Bielskypage 39
Things I Could Have SaidAngelique Jenningspage 40
AcrosticsAnnie Heisepage 40https://thekeep.eiu.edu/vehicle/1044/thumbnail.jp
The Vehicle, Fall 1984
Vol. 26, No. 1
Table of Contents
Thoughts on I-57Jim Caldwellpage 3
A Night Between Lonely and BlindJennifer K. Soulepage 4
What is Unnatural is Sometimes MagicAngelique Jenningspage 4
Cutting ClosenessBecky Lawsonpage 5
PhotoBrian Ormistonpage 6
The Sensuality of Corn One Week in AugustMichelle Mitchellpage 7
American MusicJim Caldwellpage 7
Water is WaitingMichael Kuopage 8
WhereJennifer K. Soulepage 8
The Fishing HoleJan Kowalskipage 9
Miller\u27s PondSue Gradypage 9
PhotoCathy Stonerpage 11
Young Man Reading To His LoverMaggie Kennedypage 11
ShellsChristopher R. Albinpage 12
In The ShadeJohn Fehrmannpage 12
FallLynanne Feilenpage 13
IndecisionDave L. Brydenpage 13
Dark Falls SoftlyAngelique Jenningspage 14
Not a Parked \u2757 Chevy in the Summer in the CountryMichelle Mitchellpage 20
BirdAnnie Heisepage 20
Clouds Created Only For Poets And Certain WomenJennifer K. Soulepage 21
SandGraham Lewispage 22
PhotoFred Zwickypage 23
Judgment CallCathy Moepage 23
I was hip that night Dan Hintzpage 24
A Sight Of WindDan Von Holtenpage 25
Tillard Isabel M. Parrottpage 26
The WidowMaggie Kennedypage 27
The SeparationMichelle Mitchellpage 27
The Garden Hose TrialMaggie Kennedypage 28
InterruptionsJennifer K. Soulepage 28
On Happening Across Jesus While Cleaning the BasementMaggie Kennedypage 29
GileonMichelle Mitchellpage 30
If My Father Were A Writer, He Would Still BuildAngelique Jenningspage 36
A Visit to Grandpa Gib\u27s HouseTammy Veachpage 37
For Having SeenAngelique Jenningspage 38
PhotoJudy Klancicpage 39
The Earth in BlueSusan J. Bielskypage 39
Things I Could Have SaidAngelique Jenningspage 40
AcrosticsAnnie Heisepage 40https://thekeep.eiu.edu/vehicle/1044/thumbnail.jp
THE APOGEE SPECTROSCOPIC SURVEY OF KEPLER PLANET HOSTS: FEASIBILITY, EFFICIENCY, AND FIRST RESULTS
The Kepler mission has yielded a large number of planet candidates from among the Kepler Objects of Interest(KOIs), but spectroscopic follow-up of these relatively faint stars is a serious bottleneck in confirming and characterizing these systems. We present motivation and survey design for an ongoing project with the Sloan Digital Sky Survey III multiplexed Apache Point Observatory Galactic Evolution Experiment (APOGEE) near-infrared spectrograph to monitor hundreds of KOI host stars. We report some of our first results using representative targets from our sample, which include current planet candidates that we find to be false positives, as well as candidates listed as false positives that we do not find to be spectroscopic binaries. With this survey, KOI hosts are observed over âŒ20 epochs at a radial velocity (RV) precision of 100â200msâ1. These observations can easily identify a majority of false positives caused by physically associated stellar or substellar binaries, and in many cases, fully characterize their orbits. We demonstrate that APOGEE is capable of achieving RV precision at the 100â200msâ1 level over long time baselines, and that APOGEEâs multiplexing capability makes it substantially more efficient at identifying false positives due to binaries than other single-object spectrographs working to confirm KOIs as planets. These APOGEE RVs enable ancillary science projects, such as studies of fundamental stellar astrophysics or intrinsically rare substellar companions. The coadded APOGEE spectra can be used to derive stellar properties (Teff, log g) and chemical abundances of over a dozen elements to probe correlations of planet properties with individual elemental abundances
Characteristics of planetary candidates observed by Kepler. II. Analysis of the first four months of data
On 2011 February 1 the Kepler mission released data for 156,453 stars observed from the beginning of the science observations on 2009 May 2 through September 16. There are 1235 planetary candidates with transit-like signatures detected in this period. These are associated with 997 host stars. Distributions of the characteristics of the planetary candidates are separated into five class sizes: 68 candidates of approximately Earth-size (Rp < 1.25 Râ), 288 super-Earth-size (1.25 Râ †R p < 2 Râ), 662 Neptune-size (2 R â †Rp < 6 Râ), 165 Jupiter-size (6 Râ †Rp < 15 R â), and 19 up to twice the size of Jupiter (15 R â †Rp < 22 Râ). In the temperature range appropriate for the habitable zone, 54 candidates are found with sizes ranging from Earth-size to larger than that of Jupiter. Six are less than twice the size of the Earth. Over 74% of the planetary candidates are smaller than Neptune. The observed number versus size distribution of planetary candidates increases to a peak at two to three times the Earth-size and then declines inversely proportional to the area of the candidate. Our current best estimates of the intrinsic frequencies of planetary candidates, after correcting for geometric and sensitivity biases, are 5% for Earth-size candidates, 8% for super-Earth-size candidates, 18% for Neptune-size candidates, 2% for Jupiter-size candidates, and 0.1% for very large candidates; a total of 0.34 candidates per star. Multi-candidate, transiting systems are frequent; 17% of the host stars have multi-candidate systems, and 34% of all the candidates are part of multi-candidate systems
Two Warm Super-Earths Transiting the Nearby M Dwarf TOI-2095
We report the detection and validation of two planets orbiting TOI-2095 (TIC
235678745). The host star is a 3700K M1V dwarf with a high proper motion. The
star lies at a distance of 42 pc in a sparsely populated portion of the sky and
is bright in the infrared (K=9). With data from 24 Sectors of observation
during TESS's Cycles 2 and 4, TOI-2095 exhibits two sets of transits associated
with super-Earth-sized planets. The planets have orbital periods of 17.7 days
and 28.2 days and radii of 1.30 and 1.39 Earth radii, respectively. Archival
data, preliminary follow-up observations, and vetting analyses support the
planetary interpretation of the detected transit signals. The pair of planets
have estimated equilibrium temperatures of approximately 400 K, with stellar
insolations of 3.23 and 1.73 times that of Earth, placing them in the Venus
zone. The planets also lie in a radius regime signaling the transition between
rock-dominated and volatile-rich compositions. They are thus prime targets for
follow-up mass measurements to better understand the properties of warm,
transition radius planets. The relatively long orbital periods of these two
planets provide crucial data that can help shed light on the processes that
shape the composition of small planets orbiting M dwarfs.Comment: Submitted to AAS Journal
A Giant Planet Candidate Transiting a White Dwarf
Astronomers have discovered thousands of planets outside the solar system,
most of which orbit stars that will eventually evolve into red giants and then
into white dwarfs. During the red giant phase, any close-orbiting planets will
be engulfed by the star, but more distant planets can survive this phase and
remain in orbit around the white dwarf. Some white dwarfs show evidence for
rocky material floating in their atmospheres, in warm debris disks, or orbiting
very closely, which has been interpreted as the debris of rocky planets that
were scattered inward and tidally disrupted. Recently, the discovery of a
gaseous debris disk with a composition similar to ice giant planets
demonstrated that massive planets might also find their way into tight orbits
around white dwarfs, but it is unclear whether the planets can survive the
journey. So far, the detection of intact planets in close orbits around white
dwarfs has remained elusive. Here, we report the discovery of a giant planet
candidate transiting the white dwarf WD 1856+534 (TIC 267574918) every 1.4
days. The planet candidate is roughly the same size as Jupiter and is no more
than 14 times as massive (with 95% confidence). Other cases of white dwarfs
with close brown dwarf or stellar companions are explained as the consequence
of common-envelope evolution, wherein the original orbit is enveloped during
the red-giant phase and shrinks due to friction. In this case, though, the low
mass and relatively long orbital period of the planet candidate make
common-envelope evolution less likely. Instead, the WD 1856+534 system seems to
demonstrate that giant planets can be scattered into tight orbits without being
tidally disrupted, and motivates searches for smaller transiting planets around
white dwarfs.Comment: 50 pages, 12 figures, 2 tables. Published in Nature on Sept. 17,
2020. The final authenticated version is available online at:
https://www.nature.com/articles/s41586-020-2713-
The impact of women's social position on fertility in developing countries
This paper examines ideas about possible ways in which the extent of women's autonomy, women's economic dependency, and other aspects of their position vis-Ă -vis men influence fertility in Third World populations. Women's position or âstatusâ seems likely to be related to the supply of children because of its links with age at marriage. Women's position may also affect the demand for children and the costs of fertility regulation, though some connections suggested in the literature are implausible. The paper ends with suggestions for future research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45660/1/11206_2005_Article_BF01124382.pd
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