12,254 research outputs found
Symbiotic nitrogen fixation and N-transfer in a grass-white clover mixture
Symbiotic N2 fixation (SNF) and transfer of fixed N from clover to grass in a grass-white clover mixture was measured during two years using 15N isotope dilution techniques. White clover derived from 87 to 99% of its N from the atmosphere. The total SNF ranged from 150 to 277 kg N ha-1 yr-1, which corresponded to 34-45 mg N fixed per gram of white clover dry weight. The transfer of fixed N from clover to grass corresponded to approximately 10 kg N ha-1 yr-1
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48-year-old with Coronavirus Disease 2019
Case Presentation: A 48-year-old male who presented with signs and symptoms suggestive of an upper respiratory infection was seen at an urgent care, he had a negative chest radiograph and was discharged. With no other cases of coronavirus disease 2019 (COVID-19) in the state, the patient presented to the emergency department two days later with worsening shortness of breath.Discussion: There are a variety of findings on both chest radiograph and computed tomography of the chest that suggests COVID-19
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Macaques preferentially attend to visual patterns with higher fractal dimension contours.
Animals' sensory systems evolved to efficiently process information from their environmental niches. Niches often include irregular shapes and rough textures (e.g., jagged terrain, canopy outlines) that must be navigated to find food, escape predators, and master other fitness-related challenges. For most primates, vision is the dominant sensory modality and thus, primates have evolved systems for processing complicated visual stimuli. One way to quantify information present in visual stimuli in natural scenes is evaluating their fractal dimension. We hypothesized that sensitivity to complicated geometric forms, indexed by fractal dimension, is an evolutionarily conserved capacity, and tested this capacity in rhesus macaques (Macaca mulatta). Monkeys viewed paired black and white images of simulated self-similar contours that systematically varied in fractal dimension while their attention to the stimuli was measured using noninvasive infrared eye tracking. They fixated more frequently on, dwelled for longer durations on, and had attentional biases towards images that contain boundary contours with higher fractal dimensions. This indicates that, like humans, they discriminate between visual stimuli on the basis of fractal dimension and may prefer viewing informationally rich visual stimuli. Our findings suggest that sensitivity to fractal dimension may be a wider ability of the vertebrate vision system
Cold gas in the inner regions of intermediate redshift clusters
Determining gas content and star formation rate has known remarkable progress
in field galaxies, but has been much less investigated in galaxies inside
clusters. We present the first CO observations of luminous infrared galaxies
(LIRGs) inside the virial radii of two intermediate redshift clusters,
CL1416+4446 (z=0.397) and CL0926+1242 (z=0.489). We detect three galaxies at
high significance (5 to 10 sigma), and provide robust estimates of their CO
luminosities, L'CO. In order to put our results into a general context, we
revisit the relation between cold and hot gas and stellar mass in nearby field
and cluster galaxies. We find evidence that at fixed LIR (or fixed stellar
mass), the frequency of high L'CO galaxies is lower in clusters than in the
field, suggesting environmental depletion of the reservoir of cold gas. The
level of star formation activity in a galaxy is primarily linked to the amount
of cold gas, rather than to the galaxy mass or the lookback time. In clusters,
just as in the field, the conversion between gas and stars seems universal. The
relation between LIR and L'CO for distant cluster galaxies extends the relation
of nearby galaxies to higher IR luminosities. Nevertheless, the intermediate
redshift galaxies fall well within the dispersion of the trend defined by local
systems. Considering that L'CO is generally derived from the CO(1-0) line and
sensitive to the vast majority of the molecular gas in the cold interstellar
medium of galaxies, but less to the part which will actually be used to form
stars, we suggest that molecular gas can be stripped before the star formation
rate is affected. Combining the sample of Geach et al. (2009, 2011) and ours,
we find evidence for a decrease in CO towards the cluster centers. This is the
first hint of an environmental impact on cold gas at intermediate redshift.Comment: Accepted for publication in Astronomy and Astrophysic
Brain Imaging and Privacy: How Recent Advances in Neuroimaging Implicate Privacy Concerns
This paper deals with recent advances in neuroimaging technologies which could begin to implicate privacy concerns in the near future
Mathematical and computational studies of equilibrium capillary free surfaces
The results of several independent studies are presented. The general question is considered of whether a wetting liquid always rises higher in a small capillary tube than in a larger one, when both are dipped vertically into an infinite reservoir. An analytical investigation is initiated to determine the qualitative behavior of the family of solutions of the equilibrium capillary free-surface equation that correspond to rotationally symmetric pendent liquid drops and the relationship of these solutions to the singular solution, which corresponds to an infinite spike of liquid extending downward to infinity. The block successive overrelaxation-Newton method and the generalized conjugate gradient method are investigated for solving the capillary equation on a uniform square mesh in a square domain, including the case for which the solution is unbounded at the corners. Capillary surfaces are calculated on the ellipse, on a circle with reentrant notches, and on other irregularly shaped domains using JASON, a general purpose program for solving nonlinear elliptic equations on a nonuniform quadrilaterial mesh. Analytical estimates for the nonexistence of solutions of the equilibrium capillary free-surface equation on the ellipse in zero gravity are evaluated
Female impersonation as an alternative reproductive strategy in giant cuttlefish
Out of all the animals, cephalopods possess an unrivalled ability to change their shape and body patterns. Our observations of giant cuttlefish (Sepia apama) suggest this ability has allowed them to evolve alternative mating strategies in which males can switch between the appearance of a female and that of a male in order to foil the guarding attempts of larger males. At a mass breeding aggregation in South Australia, we repeatedly observed single small males accompanying mating pairs. While doing so, the small male assumed the body shape and patterns of a female. Such males were never attacked by the larger mate-guarding male. On more than 20 occasions, when the larger male was distracted by another male intruder, these small males, previously indistinguishable from a female, were observed to change body pattern and behaviour to that of a male in mating display. These small males then attempted to mate with the female, often with success. This potential for dynamic sexual mimicry may have played a part in driving the evolution of the remarkable powers of colour and shape transformation which characterize the cephalopods
Enclosures and Dichotomies: Coexistence vs. Distance in the Poems of John Clare
John Clare’s poetry emphasizes an affinity with environment by suspending the distinction between the inside (subject) and the outside (object). Clare’s identification with objects and perception rather than subjects and aesthetics renders his work as a prescient and radical example of ecological poetry in the Romantic period. Raymond Williams’ “green language” and Timothy Morton’s ambient poetics both cite Clare as an ideal figure for their above theories and evoke Clare as a writer who positions the environment as governing thought rather than thought governing the environment. This thesis especially relates Clare to Morton’s Ecology without Nature, a study of environmental aesthetics that displaces anthropocentricism and logocentrism with object-oriented ontology (OOO) and an immersion into environmental ambience. This thesis is divided into four sections, each structured by a dichotomy with a hegemonic enclosure of subjects and objects on one side and an alternative remedy that Clare gestures his readers towards. Clare’s poems frame the creation and consumption of literature as a direct connection to our immediate surroundings and by identifying with objects, detects this circumambient and sometimes mundane space as active and sublime. Finally, the arche-writing of Jacques Derrida establishes the written word as an environment not dissimilar to forests and fields and establishes Clare’s poems as a way to sense the environment as coded rather than empty. My correspondence between Derrida’s a priori arche-writing with Clare’s poetics indicates Clare’s successfully representation of uncompromised objects in space rather than objects as inextricably linked to logocentrism’s dominating signifiers and anthropocentric rationality
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