730 research outputs found
A stroop in the hand is worth two on the laptop: superior reliability of a smartphone based alcohol stroop in the real world
Background: Attentional bias (AB) is the tendency for substance-related stimuli to grab attention. The addiction Stroop task is widely used for measuring AB in the lab, but it has poor reliability and inconsistent predictive validity. Therefore, there is a need to improve the psychometric properties of the task. Objectives: This study contrasts the internal reliability and predictive validity of a basic (general alcohol words) and an upgraded (personalized alcohol pictures) Stroop task delivered in a neutral room on a laptop computer versus a smartphone application on participants’ homes. Methods: 120 participants recruited in 2016, completed a basic and an upgraded Stroop task. Half the participants completed the tasks on a laptop computer in a neutral university room and the remainder completed the tasks on a smartphone app in their homes. Participants also self-reported their typical alcohol consumption. Results: Acceptable internal reliability was found for both basic (α = .70) and upgraded (α = .74) Stroop tasks in the home-smartphone condition, but neither had acceptable internal reliability when administered in the neutral room-computer condition (basic α = .49; upgraded α = .58). Participants showed AB toward alcohol words, but not for beer pictures, regardless of condition. None of the indices of AB was associated with individual differences in alcohol involvement, regardless of condition. Conclusion: The internal reliability of the alcohol Stroop was acceptable when administered on smartphones, in naturalistic settings, rather than on laptop computers, in neutral university rooms
Oldest known pantherine skull and evolution of the tiger
The tiger is one of the most iconic extant animals, and its origin and evolution have been intensely debated. Fossils attributable to extant pantherine species-lineages are less than 2 MYA and the earliest tiger fossils are from the Calabrian, Lower Pleistocene. Molecular studies predict a much younger age for the divergence of modern tiger subspecies at <100 KYA, although their cranial morphology is readily distinguishable, indicating that early Pleistocene tigers would likely have differed markedly anatomically from extant tigers. Such inferences are hampered by the fact that well-known fossil tiger material is middle to late Pleistocene in age. Here we describe a new species of pantherine cat from Longdan, Gansu Province, China, Panthera zdanskyi sp. nov. With an estimated age of 2.55–2.16 MYA it represents the oldest complete skull of a pantherine cat hitherto found. Although smaller, it appears morphologically to be surprisingly similar to modern tigers considering its age. Morphological, morphometric, and cladistic analyses are congruent in confirming its very close affinity to the tiger, and it may be regarded as the most primitive species of the tiger lineage, demonstrating the first unequivocal presence of a modern pantherine species-lineage in the basal stage of the Pleistocene (Gelasian; traditionally considered to be Late Pliocene). This find supports a north-central Chinese origin of the tiger lineage, and demonstrates that various parts of the cranium, mandible, and dentition evolved at different rates. An increase in size and a reduction in the relative size of parts of the dentition appear to have been prominent features of tiger evolution, whereas the distinctive cranial morphology of modern tigers was established very early in their evolutionary history. The evolutionary trend of increasing size in the tiger lineage is likely coupled to the evolution of its primary prey species
Planning tiger recovery: Understanding intraspecific variation for effective conservation
Although significantly more money is spent on the conservation of tigers than on any other threatened species, today only 3200 to 3600 tigers roam the forests of Asia, occupying only 7% of their historical range. Despite the global significance of and interest in tiger conservation, global approaches to plan tiger recovery are partly impeded by the lack of a consensus on the number of tiger subspecies or management units, because a comprehensive analysis of tiger variation is lacking. We analyzed variation among all nine putative tiger subspecies, using extensive data sets of several traits [morphological (craniodental and pelage), ecological, molecular]. Our analyses revealed little variation and large overlaps in each trait among putative subspecies, and molecular data showed extremely low diversity because of a severe Late Pleistocene population decline. Our results support recognition of only two subspecies: the Sunda tiger, Panthera tigris sondaica, and the continental tiger, Panthera tigris tigris, which consists of two (northern and southern) management units. Conservation management programs, such as captive breeding, reintroduction initiatives, or trans-boundary projects, rely on a durable, consistent characterization of subspecies as taxonomic units, defined by robust multiple lines of scientific evidence rather than single traits or ad hoc descriptions of one or few specimens. Our multiple-trait data set supports a fundamental rethinking of the conventional tiger taxonomy paradigm, which will have profound implications for the management of in situ and ex situ tiger populations and boost conservation efforts by facilitating a pragmatic approach to tiger conservation management worldwid
A Closer Look at Exoplanet Occurrence Rates: Considering the Multiplicity of Stars without Detected Planets
One core goal of the Kepler mission was to determine the frequency of Earth-like planets that orbit Sun-like stars. Accurately estimating this planet occurrence rate requires both a well-vetted list of planets and a clear understanding of the stars searched for planets. Previous ground-based follow-up observations have, through a variety of methods, sought to improve our knowledge of stars that are known to host planets. Kepler targets without detected planets, however, have not been subjected to the same intensity of follow-up observations. In this paper, we constrain better the stellar multiplicity for stars around which Kepler could have theoretically detected a transiting Earth-sized planet in the habitable zone. We subsequently aim to improve estimates of the exoplanet search completeness—the fraction of exoplanets that were detected by Kepler—with our analysis. By obtaining adaptive optics observations of 71 Kepler target stars from the Shane 3 m telescope at Lick Observatory, we detected 14 candidate stellar companions within 4'' of 13 target stars. Of these 14 candidate stellar companions, we determine through multiple independent methods that 3 are likely to be bound to their corresponding target star. We then assess the impact of our observations on exoplanet occurrence rate calculations, finding an increase in occurrence of 6% (0.9σ) for various estimates of the frequency of Earth-like planets and an increase of 26% (4.5σ) for super-Earths and sub-Neptunes. These occurrence increases are not entirely commensurate with theoretical predictions, though this discrepancy may be due to differences in the treatment of stellar binarity
NEBRASKA AGRICULTURAL WATER MANAGEMENT DEMONSTRATION NETWORK (NAWMDN): INTEGRATING RESEARCH AND EXTENSION/OUTREACH
Maximizing the net benefits of irrigated plant production through appropriately designed agricultural water management programs is of growing importance in Nebraska, and other western and Midwestern states, because many areas are involved in management and policy changes to conserve irrigation water. In Nebraska, farmers are being challenged to practice conservation methods and use water resources more efficiently while meeting plant water requirements and maintaining high yields. Another challenge Nebraska experiences in it\u27s approximately 3.5‐million‐ha irrigated lands is limited adoption of newer technologies/tools to help farmers better manage irrigation, conserve water and energy, and increase plant water use efficiency. In 2005, the Nebraska Agricultural Water Management Demonstration Network (NAWMDN or Network) was formed from an interdisciplinary team of partners including the Natural Resources Districts (NRD); USDA‐NRCS; farmers from south central, northeast, west central, and western Nebraska; crop consultants; and University of Nebraska‐Lincoln faculty. The main goal of the Network is to enable the transfer of high quality research‐based information to Nebraskans through a series of demonstration projects established in farmers\u27 fields and implement newer tools and technologies to address and enhance plant water use efficiency, water conservation, and reduce energy consumption for irrigation. The demonstration projects are supported by the scientifically‐based field research and evaluation projects conducted at the University of Nebraska‐Lincoln, South Central Agricultural Laboratory located near Clay Center, Nebraska. The Network was formed with only 15 farmers as collaborators in only one of the 23 NRDs in 2005. As of late 2009, the number of active collaborators has increased to over 300 in 12 NRDs and 35 of 93 counties. The Network is impacting both water and energy conservation due to farmers adopting information and newer technologies for irrigation management. The NAWMDN is helping participants to improve irrigation management and efficiency by monitoring plant growth stages and development, soil moisture, and crop evapotranspiration. As a result, they are reducing irrigation water application amounts and associated energy savings is leading to greater profitability to participating farmers. This article describes the goals and objectives of the Network, technical and educational components, operational functions, and procedures used in the NAWMDN. The quantitative impacts in terms of water and energy conservation are reported
Nebraska Agricultural Water Management Demonstration Network (NAWMDN): Integrating Research and Extension/Outreach
Maximizing the net benefits of irrigated plant production through appropriately designed agricultural water management programs is of growing importance in Nebraska, and other western and Midwestern states, because many areas are involved in management and policy changes to conserve irrigation water. In Nebraska, farmers are being challenged to practice conservation methods and use water resources more efficiently while meeting plant water requirements and maintaining high yields. Another challenge Nebraska experiences in it\u27s approximately 3.5‐million‐ha irrigated lands is limited adoption of newer technologies/tools to help farmers better manage irrigation, conserve water and energy, and increase plant water use efficiency. In 2005, the Nebraska Agricultural Water Management Demonstration Network (NAWMDN or Network) was formed from an interdisciplinary team of partners including the Natural Resources Districts (NRD); USDA‐NRCS; farmers from south central, northeast, west central, and western Nebraska; crop consultants; and University of Nebraska‐Lincoln faculty. The main goal of the Network is to enable the transfer of high quality research‐based information to Nebraskans through a series of demonstration projects established in farmers\u27 fields and implement newer tools and technologies to address and enhance plant water use efficiency, water conservation, and reduce energy consumption for irrigation. The demonstration projects are supported by the scientifically‐based field research and evaluation projects conducted at the University of Nebraska‐Lincoln, South Central Agricultural Laboratory located near Clay Center, Nebraska. The Network was formed with only 15 farmers as collaborators in only one of the 23 NRDs in 2005. As of late 2009, the number of active collaborators has increased to over 300 in 12 NRDs and 35 of 93 counties. The Network is impacting both water and energy conservation due to farmers adopting information and newer technologies for irrigation management. The NAWMDN is helping participants to improve irrigation management and efficiency by monitoring plant growth stages and development, soil moisture, and crop evapotranspiration. As a result, they are reducing irrigation water application amounts and associated energy savings is leading to greater profitability to participating farmers. This article describes the goals and objectives of the Network, technical and educational components, operational functions, and procedures used in the NAWMDN. The quantitative impacts in terms of water and energy conservation are reported
Evolution of Skull and Mandible Shape in Cats (Carnivora: Felidae)
The felid family consists of two major subgroups, the sabretoothed and the feline cats, to which all extant species belong, and are the most anatomically derived of all carnivores for predation on large prey with a precision killing bite. There has been much controversy and uncertainty about why the skulls and mandibles of sabretoothed and feline cats evolved to become so anatomically divergent, but previous models have focused on single characters and no unifying hypothesis of evolutionary shape changes has been formulated. Here I show that the shape of the skull and mandible in derived sabrecats occupy entirely different positions within overall morphospace from feline cats, and that the evolution of skull and mandible shape has followed very different paths in the two subgroups. When normalised for body-size differences, evolution of bite forces differ markedly in the two groups, and are much lower in derived sabrecats, and they show a significant relationship with size and cranial shape, whereas no such relationship is present in feline cats. Evolution of skull and mandible shape in modern cats has been governed by the need for uniform powerful biting irrespective of body size, whereas in sabrecats, shape evolution was governed by selective pressures for efficient predation with hypertrophied upper canines at high gape angles, and bite forces were secondary and became progressively weaker during sabrecat evolution. The current study emphasises combinations of new techniques for morphological shape analysis and biomechanical studies to formulate evolutionary hypotheses for difficult groups
K2 Discovers a Busy Bee: An Unusual Transiting Neptune Found in the Beehive Cluster
Open clusters have been the focus of several exoplanet surveys but only a few
planets have so far been discovered. The \emph{Kepler} spacecraft revealed an
abundance of small planets around small, cool stars, therefore, such cluster
members are prime targets for exoplanet transit searches. Kepler's new mission,
K2, is targeting several open clusters and star-forming regions around the
ecliptic to search for transiting planets around their low-mass constituents.
Here, we report the discovery of the first transiting planet in the
intermediate-age (800 Myr) Beehive cluster (Praesepe). K2-95 is a faint
() dwarf from K2's Campaign 5
with an effective temperature of , approximately
solar metallicity and a radius of . We
detected a transiting planet with a radius of and an orbital period of 10.134 days. We combined photometry,
medium/high-resolution spectroscopy, adaptive optics/speckle imaging and
archival survey images to rule out any false positive detection scenarios,
validate the planet, and further characterize the system. The planet's radius
is very unusual as M-dwarf field stars rarely have Neptune-sized transiting
planets. The comparatively large radius of K2-95b is consistent with the other
recently discovered cluster planets K2-25b (Hyades) and K2-33b (Upper
Scorpius), indicating systematic differences in their evolutionary states or
formation. These discoveries from K2 provide a snapshot of planet formation and
evolution in cluster environments and thus make excellent laboratories to test
differences between field-star and cluster planet populations.Comment: 14 pages, 8 figues. Accepted for publication in A
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The influence of stratospheric vortex displacements and splits on surface climate
A strong link exists between stratospheric variability and anomalous weather patterns at the earth’s surface. Specifically, during extreme variability of the Arctic polar vortex termed a “weak vortex event,” anomalies can descend from the upper stratosphere to the surface on time scales of weeks. Subsequently the outbreak of cold-air events have been noted in high northern latitudes, as well as a quadrupole pattern in surface temperature over the Atlantic and western European sectors, but it is currently not understood why certain events descend to the surface while others do not. This study compares a new classification technique of weak vortex events, based on the distribution of potential vorticity, with that of an existing technique and demonstrates that the subdivision of such events into vortex displacements and vortex splits has important implications for tropospheric weather patterns on weekly to monthly time scales. Using reanalysis data it is found that vortex splitting events are correlated with surface weather and lead to positive temperature anomalies over eastern North America of more than 1.5 K, and negative anomalies over Eurasia of up to −3 K. Associated with this is an increase in high-latitude blocking in both the Atlantic and Pacific sectors and a decrease in European blocking. The corresponding signals are weaker during displacement events, although ultimately they are shown to be related to cold-air outbreaks over North America. Because of the importance of stratosphere–troposphere coupling for seasonal climate predictability, identifying the type of stratospheric variability in order to capture the correct surface response will be necessary
Fundamental Properties of Kepler Planet-Candidate Host Stars using Asteroseismology
We have used asteroseismology to determine fundamental properties for 66
Kepler planet-candidate host stars, with typical uncertainties of 3% and 7% in
radius and mass, respectively. The results include new asteroseismic solutions
for four host stars with confirmed planets (Kepler-4, Kepler-14, Kepler-23 and
Kepler-25) and increase the total number of Kepler host stars with
asteroseismic solutions to 77. A comparison with stellar properties in the
planet-candidate catalog by Batalha et al. shows that radii for subgiants and
giants obtained from spectroscopic follow-up are systematically too low by up
to a factor of 1.5, while the properties for unevolved stars are in good
agreement. We furthermore apply asteroseismology to confirm that a large
majority of cool main-sequence hosts are indeed dwarfs and not misclassified
giants. Using the revised stellar properties, we recalculate the radii for 107
planet candidates in our sample, and comment on candidates for which the radii
change from a previously giant-planet/brown-dwarf/stellar regime to a
sub-Jupiter size, or vice versa. A comparison of stellar densities from
asteroseismology with densities derived from transit models in Batalha et al.
assuming circular orbits shows significant disagreement for more than half of
the sample due to systematics in the modeled impact parameters, or due to
planet candidates which may be in eccentric orbits. Finally, we investigate
tentative correlations between host-star masses and planet candidate radii,
orbital periods, and multiplicity, but caution that these results may be
influenced by the small sample size and detection biases.Comment: 19 pages, 10 figures, 4 tables; accepted for publication in ApJ;
machine-readable versions of tables 1-3 are available as ancillary files or
in the source code; v2: minor changes to match published versio
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