557 research outputs found
Improved spatial separation of neutral molecules
We have developed and experimentally demonstrated an improved electrostatic
deflector for the spatial separation of molecules according to their
dipole-moment-to-mass ratio. The device features a very open structure that
allows for significantly stronger electric fields as well as for stronger
deflection without molecules crashing into the device itself. We have
demonstrated its performance using the prototypical OCS molecule and we discuss
opportunities regarding improved quantum-state-selectivity for complex
molecules and the deflection of unpolar molecules.Comment: 6 figure
Cool habitats support darker and bigger butterflies in Australian tropical forests
published_or_final_versio
Verbetering van de lichtonderschepping in een tomatengewas door aanpassing van de rijstructuur: Effecten van de rijstructuur op lichtverdeling, fotosynthese en productie
Doel van dit project was te onderzoeken wat het effect is van de rijstructuur op de lichtverdeling en fotosynthese van een tomatengewas, en de effecten daarvan op de productie. Ook werd gekeken of de bladstand en de fotosynthesecapaciteit van de bladeren zich aanpassen aan wijzigende lichtverdeling. Tevens werd de hypothese getest of alternatieve vormen van tussenplanten zouden leiden tot lagere verdamping en dus tot energiebesparing. Verder is gekeken naar het effect op productie van twee substraten, namelijk kokosmatten type ‘Profit’ van Van der Knaap, en steenwolmat type ‘Master Dry’ van Grodan
Quantum-classical transition in Scale Relativity
The theory of scale relativity provides a new insight into the origin of
fundamental laws in physics. Its application to microphysics allows us to
recover quantum mechanics as mechanics on a non-differentiable (fractal)
spacetime. The Schrodinger and Klein-Gordon equations are demonstrated as
geodesic equations in this framework. A development of the intrinsic properties
of this theory, using the mathematical tool of Hamilton's bi-quaternions, leads
us to a derivation of the Dirac equation within the scale-relativity paradigm.
The complex form of the wavefunction in the Schrodinger and Klein-Gordon
equations follows from the non-differentiability of the geometry, since it
involves a breaking of the invariance under the reflection symmetry on the
(proper) time differential element (ds - ds). This mechanism is generalized
for obtaining the bi-quaternionic nature of the Dirac spinor by adding a
further symmetry breaking due to non-differentiability, namely the differential
coordinate reflection symmetry (dx^mu - dx^mu) and by requiring invariance
under parity and time inversion. The Pauli equation is recovered as a
non-relativistic-motion approximation of the Dirac equation.Comment: 28 pages, no figur
Australian Sphingidae – DNA Barcodes Challenge Current Species Boundaries and Distributions
© 2014 Rougerie et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article
Increasing human dominance of tropical forests
Tropical forests house over half of Earth’s biodiversity and are an important influence on the climate system. These forests are experiencing escalating human influence, altering their health and the provision of important ecosystem functions and services. Impacts started with hunting and millennia-old megafaunal extinctions (Phase I), continuing via low-intensity shifting cultivation (Phase II), to today’s global integration (Phase III), dominated by intensive permanent agriculture, industrial logging, and attendant fires and fragmentation. Such ongoing pressures together with an intensification of global environmental change may severely degrade forests in the future (Phase IV, global simplification) unless new ‘development without destruction’ pathways are established alongside climate change resilient landscape designs
Detecting and correcting partial errors: Evidence for efficient control without conscious access
Appropriate reactions to erroneous actions are essential to keeping behavior adaptive. Erring, however, is not an all-or-none process: electromyographic (EMG) recordings of the responding muscles have revealed that covert incorrect response activations (termed "partial errors") occur on a proportion of overtly correct trials. The occurrence of such "partial errors" shows that incorrect response activations could be corrected online, before turning into overt errors. In the present study, we showed that, unlike overt errors, such "partial errors" are poorly consciously detected by participants, who could report only one third of their partial errors. Two parameters of the partial errors were found to predict detection: the surface of the incorrect EMG burst (larger for detected) and the correction time (between the incorrect and correct EMG onsets; longer for detected). These two parameters provided independent information. The correct(ive) responses associated with detected partial errors were larger than the "pure-correct" ones, and this increase was likely a consequence, rather than a cause, of the detection. The respective impacts of the two parameters predicting detection (incorrect surface and correction time), along with the underlying physiological processes subtending partial-error detection, are discussed
Habitat specificity of a threatened and endemic cliff-dwelling halophyte
Research ArticleCoastal areas and other saline environments are major contributors to regional and global biodiversity
patterns. In these environments, rapidly changing gradients require highly specialized plants like halophytes.
In European coastal cliff-tops, rocky and sandy seashores, and saltmarshes, typical halophytes from the genus
Limonium are commonly found. Among them, the aneuploid tetraploid (2n ¼ 4x ¼ 35, 36, 37) Limonium multiflorum,
endemic to the west coast of Portugal, is an interesting case study for investigating the ecology and conservation
of a halophyte agamospermic species. Although it is listed in the IUCN red list of threatened species,
information on its population size or rarity, as well as its ecology, in some respects is still unknown. Field surveys
in the largest known population were performed (Raso cape, Portugal) in order to determine habitat requirements
and conservation status. A total of 88 quadrats were monitored, 43 of which contained at least one L. multiflorum
individual. For each sampled quadrat, four abiotic and four biotic variables as well as two spatially derived variables
were recorded. Principal component analysis and cluster analysis showed narrow habitat specificity for this species
which appeared to be intolerant to competition with invasive alien plants. We conclude that in situ conservation
in a local ‘hotspot’ of this rare and vulnerable species emerges as a priority in order to ensure that biodiversity is not los
A 12-week lifestyle intervention: effects on fatigue, fear, and nutritional status in children with a Fontan circulation
INTRODUCTION: Children and adolescents with a Fontan circulation are less physically active compared to healthy peers. In the current study, effects of a 12-week lifestyle intervention on fatigue, fears regarding exercise, caloric intake, rest energy expenditure (REE), and body composition were measured in children with a Fontan circulation.METHODS: This study was a semi-cross-over randomized controlled trial. The lifestyle intervention consisted of a 12-week high-weight resistance training (three supervised training sessions a week) supported by high-protein diet (>2 g/kg) and tailored recommended caloric intake. Fatigue (measured by the validated PedsQol Multidimensional Fatigue Scale), fears regarding exercise (measured on a fear thermometer), REE (measured using indirect calorimetry), caloric intake and body composition using air displacement plethysmography, and four-skinfold method were measured before and after the intervention and control period.RESULTS: Twenty-seven pediatric Fontan patients, median age 12.9 years (IQR: 10.5-16.2), of the included 28 patients successfully completed the program. Before training, both child- and parent-reported levels of fatigue were significantly worse on all domains (general, sleep/rest, and cognitive fatigue) compared to healthy peers. After training, parent-reported fatigue significantly improved on the general and cognitive fatigue domains [effect size +16 points (7-25), p < 0.001, and +10 points (2-17), p = 0.015, compared to the control period]. Before training, fear regarding exercise scored on the fear thermometer was low for both children and parents (median score 1 and 2, respectively, on a scale of 0-8). After training, child-reported fear decreased further compared to the control period [effect size -1.4 points (-2.3 to -0.6), p = 0.001]. At baseline, children had increased REE +12% compared to reference values, which did not change after exercise. Children ate an average of 637 calories below recommended intake based on REE, caloric deficit became smaller after the intervention, and protein intake increased compared to the control period [-388 calories (-674 to -102), p = 0.008, and +15 g (0.4-30), p = 0.044]. Body fat percentage did not change significantly. CONCLUSION: A 12-week lifestyle intervention improved parent-reported fatigue symptoms in the children, further decreased child-reported fears, and increased caloric and protein intake.</p
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