2,061 research outputs found
Multiplicative scale uncertainties in the unified approach for constructing confidence intervals
We have investigated how uncertainties in the estimation of the detection
efficiency affect the 90% confidence intervals in the unified approach for
constructing confidence intervals. The study has been conducted for experiments
where the number of detected events is large and can be described by a Gaussian
probability density function. We also assume the detection efficiency has a
Gaussian probability density and study the range of the relative uncertainties
between 0 and 30%. We find that the confidence intervals
provide proper coverage over a wide signal range and increase smoothly and
continuously from the intervals that ignore scale uncertainties with a
quadratic dependence on .Comment: 22 pages, 7 figures, 2 table
Radioactive Decay Studies of Nuclei Produced from Bombardment by Intermediate-Energy Neutrons
This work was supported by National Science Foundation Grant PHY 76-84033 and Indiana Universit
Studies of 49≤Z≤51 and N≥50 Nuclei at Intermediate Energies
This work was supported by National Science Foundation Grant PHY 75-00289 and Indiana Universit
Radioactive Decay Studies of Nuclei Produced from Bombardment by Intermediate-Energy Neutrons
This work was supported by National Science Foundation Grant PHY 75-00289 and Indiana Universit
Massive quantum fields in a conical background
Representations of the Klein-Gordon and Dirac propagators are determined in a
dimensional conical background for massive fields twisted by an arbitrary
angle . The Dirac propagator is shown to be obtained from the
Klein-Gordon propagator twisted by angles where
is the cone deficit angle. Vacuum expectation values are determined
by a point-splitting method in the proper time representation of the
propagators. Analogies with the Aharonov-Bohm effect are pointed out throughout
the paper and a conjecture on an extension to fields of arbitrary spin is
given.Comment: Propagator (11) is rewritten in a more convenient form and the one
before that is amended. A more concise expression is given for the energy
density of a twisted spinor. The references contain minor correction
Large herbivore assemblages in a changing climate: incorporating water dependence and thermoregulation.
The coexistence of different species of large herbivores (ungulates) in grasslands and savannas has fascinated ecologists for decades. However, changes in climate, land-use and trophic structure of ecosystems increasingly jeopardise the persistence of such diverse assemblages. Body size has been used successfully to explain ungulate niche differentiation with regard to food requirements and predation sensitivity. But this single trait axis insufficiently captures interspecific differences in water requirements and thermoregulatory capacity and thus sensitivity to climate change. Here, we develop a two-dimensional trait space of body size and minimum dung moisture content that characterises the combined food and water requirements of large herbivores. From this, we predict that increased spatial homogeneity in water availability in drylands reduces the number of ungulate species that will coexist. But we also predict that extreme droughts will cause the larger, water-dependent grazers as wildebeest, zebra and buffalo-dominant species in savanna ecosystems - to be replaced by smaller, less water-dependent species. Subsequently, we explore how other constraints such as predation risk and thermoregulation are connected to this two-dimensional framework. Our novel framework integrates multiple simultaneous stressors for herbivores and yields an extensive set of testable hypotheses about the expected changes in large herbivore community composition following climate change
Alzheimer disease genetic risk factor APOE e4, and cognitive abilities in 111,739 UK Biobank participants
Background: the apolipoprotein (APOE) e4 locus is a genetic risk factor for dementia. Carriers of the e4 allele may be more
vulnerable to conditions that are independent risk factors for cognitive decline, such as cardiometabolic diseases.
Objective: we tested whether any association with APOE e4 status on cognitive ability was larger in older ages or in those
with cardiometabolic diseases.
Subjects: UK Biobank includes over 500,000 middle- and older aged adults who have undergone detailed medical and cognitive
phenotypic assessment. Around 150,000 currently have genetic data. We examined 111,739 participants with complete
genetic and cognitive data.
Methods: baseline cognitive data relating to information processing speed, memory and reasoning were used. We tested for
interactions with age and with the presence versus absence of type 2 diabetes (T2D), coronary artery disease (CAD) and hypertension.
Results: in several instances, APOE e4 dosage interacted with older age and disease presence to affect cognitive scores. When
adjusted for potentially confounding variables, there was no APOE e4 effect on the outcome variables.
Conclusions: future research in large independent cohorts should continue to investigate this important question, which has
potential implications for aetiology related to dementia and cognitive impairment
CrRLK1L receptor‐like kinases HERK1 and ANJEA are female determinants of pollen tube reception
Communication between the gametophytes is vital for angiosperm fertilisation. Multiple CrRLK1L‐type receptor kinases prevent premature pollen tube burst, while another CrRLK1L protein, FERONIA (FER), is required for pollen tube reception in the female gametophyte. We report here the identification of two additional CrRLK1L homologues, HERCULES RECEPTOR KINASE 1 (HERK1) and ANJEA (ANJ), which act redundantly to promote pollen tube growth arrest at the synergid cells. HERK1 and ANJ localise to the filiform apparatus of the synergid cells in unfertilised ovules, and in herk1 anj mutants, a majority of ovules remain unfertilised due to pollen tube overgrowth, together indicating that HERK1 and ANJ act as female determinants for fertilisation. As in fer mutants, the synergid cell‐specific, endomembrane protein NORTIA (NTA) is not relocalised after pollen tube reception; however, unlike fer mutants, reactive oxygen species levels are unaffected in herk1 anj double mutants. Both ANJ and HERK1 associate with FER and its proposed co‐receptor LORELEI (LRE) in planta. Together, our data indicate that HERK1 and ANJ act with FER to mediate female–male gametophyte interactions during plant fertilisation
Time resolution of Burle 85001 micro-channel plate photo-multipliers in comparison with Hamamatsu R2083
The CLAS detector will require improvements in its particle identification
system to take advantage of the higher energies provided by the Jefferson
Laboratory accelerator upgrade to 12 GeV. To this end, we have studied the
timing characteristics of the micro-channel plate photo-multiplier 85001 from
Burle, which can be operated in a high magnetic field environment.
For reference and comparison, measurements were also made using the standard
PMT R2083 from Hamamatsu using two timing methods.
The cosmic ray method, which utilizes three identical scintillating counters
2cmx3cmx50cm with PMs at the ends, yields 59.1(0.7)ps.
The location method of particles from radiative source with known coordiantes
has been used to compare timing resolutions of R2083 and Burle-85001.This
``coordinate method'' requires only one counter instrumented with two PMs and
it yields 59.5(0.7)ps.
For the micro-channel plate photomultiplier from Burle with an external
amplification of 10 to the signals, the coordinate method yields 130(4)ps.
This method also makes it possible to estimate the number of primary
photo-electrons.Comment: 23 pages, 13 figure
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