515 research outputs found
Possible solution of the Coriolis attenuation problem
The most consistently useful simple model for the study of odd deformed
nuclei, the particle-rotor model (strong coupling limit of the core-particle
coupling model) has nevertheless been beset by a long-standing problem: It is
necessary in many cases to introduce an ad hoc parameter that reduces the size
of the Coriolis interaction coupling the collective and single-particle
motions. Of the numerous suggestions put forward for the origin of this
supplementary interaction, none of those actually tested by calculations has
been accepted as the solution of the problem. In this paper we seek a solution
of the difficulty within the framework of a general formalism that starts from
the spherical shell model and is capable of treating an arbitrary linear
combination of multipole and pairing forces. With the restriction of the
interaction to the familiar sum of a quadrupole multipole force and a monopole
pairing force, we have previously studied a semi-microscopic version of the
formalism whose framework is nevertheless more comprehensive than any
previously applied to the problem. We obtained solutions for low-lying bands of
several strongly deformed odd rare earth nuclei and found good agreement with
experiment, except for an exaggerated staggering of levels for K=1/2 bands,
which can be understood as a manifestation of the Coriolis attenuation problem.
We argue that within the formalism utilized, the only way to improve the
physics is to add interactions to the model Hamiltonian. We verify that by
adding a magnetic dipole interaction of essentially fixed strength, we can fit
the K=1/2 bands without destroying the agreement with other bands. In addition
we show that our solution also fits 163Er, a classic test case of Coriolis
attenuation that we had not previously studied.Comment: revtex, including 7 figures(postscript), submitted to Phys.Rev.
A sports headlight retrofitted on magnifying loupes: A simple and cheap method for daily use
Medical professionals such as doctors, nurses and paramedics often use headlight to examine or to perform surgical intervention in the patients. However, there are concerns related to its use such as comfort for the user, mobility and asepsis for the cable, availability in the departments plus cost effectiveness. The concept of a retrofitted 1-watt sports headlight (adjusted on magnifying loupes) would give quick access to a light source, be available and reliable at any place, save vital funds and would be environmentally friendly as the battery can be replaced. The same concept can be applied to pre-hospital emergency care and disaster medicine as well. BACKGROUND Headlights with fibre optic cables have being used for two decades as an adjunct to the operating theatre lighting. The cable-powered headlights pose, to our experience, some limitations for the operating team: Smooth personnel circulation around the operating field is hindered by repeated unplugging and re-plugging of the cable when surgeon and assistants change sides. Protocols for draping and asepsis have to accommodate the cumbersome cable and the light source and in addition are time consuming and arising issues of flexibility. The weight of the headlight and cable may cause health issues for the bearer (head ache, low back pain) [1]. Portable surgical headlights have also been available for the last decade for a not negligible cost. They are powered by a battery pack, attached to the torso/waist and connected to the headlight by a shorter cable. They are priced at hundreds of pounds. METHOD As an alternative to cumbersome cables and expensive âad hocâ designs, we use a retrofitted 1-watt sports headlight with a weight of 100 grams. We acquired that for $ 14.99 (approximately ÂŁ10) from an outdoor specialist retailer (Petzl America, Clearfield, Utah, USA). The headlight is powered by three 1.5 Volt AAA batteries and provides 60 lumen of luminous flux (Fig.1). We have wrapped the elastic bands of the headlight around the corresponding horizontal (axial circumferential) and sagittal elements of the headband, where the magnifying loupes are mounted (Keeler Ltd., Clewer Hill Road, Windsor SL4 4AA). The headlight can be aimed by tilting the housing (Fig.1, 2). DISCUSSION The luminous flux from our headlight according to our experience in cardiothoracic surgery is adequate for a variety of procedures: femoral and axillary arterial access, harvesting internal thoracic (mammary) arteries, open pulmonary resections, valve surgery. Being fully portable without cable, light source or pouches, it is especially handy outside the operating suite (ITU, A&E, wards) for emergency re-explorations for bleeding, secondary wound closures, application of vacuum therapy dressings, trauma, for ECMO work etc. Finally, we have had no evidence of thermal injury, as has being reported from strong xenon beams [2]. This simple affordable headlight system can be easily adapted to the needs of the entire spectrum of surgical specialties, especially those using magnifying loupes. Therefore, can be part of basic life support kits for use in prehospital emergency care, disaster and military medicine [3]. The device has the following advantages: 1. ââTwo-in-oneââ function of Loupes and Torch. 2. Battery can be changed (so no need to throw away the item) and is environmentally friendly 3. No need for asepsis 4. Cost effective 5. Availability everywhere In conclusion, we believe this is a practical medical device
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Bait preference field study for the California ground squirrel
A bait preference field study of the California ground squirrel (Spermophilus beecheyi beecheyi) was performed involving the comparison of the following untreated bait formulations fed ad lib: oat groats, Ramik Green, and ZP Rodent Ag Bait. The study was performed on rangeland at California Polytechnic State University, San Luis Obispo, California, from March 11, 1984, to September 15, 1984. Poor bait quality problems occurred in the early period of the study (March 11 to May 17), resulting in poor acceptance of both Ramik and Ag Bait. A descriptive analysis of this period is discussed. The statistical analysis of relative bait consumption (June 3 to September 15) determined a significant difference between the consumption of oat groats versus Ramik and Ag Bait; no significant difference between Ramik and Ag Bait; the acceptance of all three baits was good; and the use of any of the three would result in control of the ground squirrels. There was a strong correlation between overall bait consumption and the ground squirrels observed
Derivation and assessment of strong coupling core-particle model from the Kerman-Klein-D\"onau-Frauendorf theory
We review briefly the fundamental equations of a semi-microscopic
core-particle coupling method that makes no reference to an intrinsic system of
coordinates. We then demonstrate how an intrinsic system can be introduced in
the strong coupling limit so as to yield a completely equivalent formulation.
It is emphasized that the conventional core-particle coupling calculation
introduces a further approximation that avoids what has hitherto been the most
time-consuming feature of the full theory, and that this approximation can be
introduced either in the intrinsic system, the usual case, or in the laboratory
system, our preference. A new algorithm is described for the full theory that
largely removes the difference in complexity between the two types of
calculation. Comparison of the full and approximate theories for some
representative cases provides a basis for the assessment of the accuracy of the
traditional approach. We find that for well-deformed nuclei, e.g. 157Gd and
157Tb, the core-coupling method and the full theory give similar results.Comment: revtex, 3 figures(postscript), submitted to Phys.Rev.
Kerman-Klein-Donau-Frauendorf model for odd-odd nuclei: formal theory
The Kerman-Klein-Donau-Frauendorf (KKDF) model is a linearized version of the
Kerman-Klein (equations of motion) formulation of the nuclear many-body
problem. In practice, it is a generalization of the standard core-particle
coupling model that, like the latter, provides a description of the
spectroscopy of odd nuclei in terms of the properties of neighboring even
nuclei and of single-particle properties, that are the input parameters of the
model. A divers sample of recent applications attest to the usefulness of the
model. In this paper, we first present a concise general review of the
fundamental equations and properties of the KKDF model. We then derive a
corresponding formalism for odd-odd nuclei that relates their properties to
those of four neighboring even nuclei, all of which enter if one is to include
both multipole and pairing forces. We treat these equations in two ways. In the
first we make essential use of the solutions of the neighboring odd nucleus
problem, as obtained by the KKDF method. In the second, we relate the
properties of the odd-odd nuclei directly to those of the even nuclei. For both
choices, we derive equations of motion, normalization conditions, and an
expression for transition amplitudes. We also solve the problem of choosing the
subspace of physical solutions that arises in an equations of motion approach
that includes pairing interactions.Comment: 27 pages, Late
Development of processing stress diacritics in reading Greek
In Greek orthography, stress position is marked with a diacritic. We investigated the developmental course of processing the stress diacritic in Grades 2 to 4. Ninety children read 108 pseudowords presented without or with a diacritic either in the same or in a different position relative to the source word. Half of the pseudowords resembled the words they were derived from. Results showed that lexical sources of stress assignment were active in Grade 2 and remained stronger than the diacritic through Grade 4. The effect of the diacritic increased more rapidly and approached the lexical effect with increasing grade. In a second experiment, 90 children read 54 words and 54 pseudowords. The pattern of results for words was similar to that for nonwords suggesting that findings regarding stress assignment using nonwords may generalize to word reading. Decoding of the diacritic does not appear to be the preferred option for developing readers
Further application of a semi-microscopic core-particle coupling method to the properties of Gd155,157, and Dy159
In a previous paper a semi-microscopic core-particle coupling method that
includes the conventional strong coupling core-particle model as a limiting
case, was applied to spectra and electromagnetic properties of several
well-deformed odd nuclei. This work, coupled a large single-particle space to
the ground state bands of the neighboring even cores. In this paper, we
generalize the theory to include excited bands of the cores, such as beta and
gamma bands, and thereby show that the resulting theory can account for the
location and structure of all bands up to about 1.5 MeV.Comment: 15 pages including 9 figure(postscript), submitted to Phys.Rev.
THE 2D:4D RATIO, HANDEDNESS, AND SEX ACROSS THE AGE SPAN
The ratio of the difference between the 2nd and 4th digits of the hand (2D:4D ratio) has been demonstrated to be an indirect indicator of prenatal testosterone levels. Prenatal testosterone has been found to play a role in brain development in utero, and thus may influence lateral asymmetries, such as handedness. Consequently, one of the aims of the current study was to examine relationships between the 2D:4D ratio, hand preference, and hand performance with the factors of sex (males and females), handedness (right handers and left handers), and age considered. A total of 104 participants were tested, 90 right handers and 14 left handers (age range = 5-to-90, mean age = 31.93, SD = 20.18, females = 58). Participants completed the Waterloo Handedness Questionnaire (WHQ) as an indicator of hand preference and the Tapley- Bryden Dot Marking (TBDM) task to evaluate hand performance. Right and left 2D:4D ratios were measured for all participants using Vernier calipers, measured to the nearest 0.01mm. Regardless of age and sex, left handers had significantly reduced hand preference strength and trended in having reduced hand performance differences between the hands. Furthermore, although only significant in the 50+ years age group, it appeared as though males tended to have decreased handedness compared to females. No significant relationships nor main effects were found with regards to the 2D:4D ratios measured, though.
Additional testing was conducted including participants with ASD, who have been illustrated to have lower than average 2D:4D ratios, as well as increased hand ambiguity. Relationships were examined between the 2D:4D ratio, hand preference, and hand performance and comparisons were analyzed between neurotypical participants and participants with ASD. A total of 5 participants with ASD were tested, 4 right handers and 1 left hander (age range = 6-to- 36, 5 males). With the small sample size, all relationships were found to be insignificant and were not generalizable. Comparisons did display significant differences in hand performance, where individuals with ASD illustrated greater hand ambiguity.
Overall, the study has demonstrated that sex, handedness, and age influence hand preference and hand performance. However, no relationships were found between handedness and the 2D:4D ratios. Moreover, continuing research on hand ambiguity in individuals with ASD could better the understanding of brain lateralization
Application of the Kerman-Klein method to the solution of a spherical shell model for a deformed rare-earth nucleus
Core-particle coupling models are made viable by assuming that core
properties such as matrix elements of multipole and pairing operators and
excitation spectra are known independently. From the completeness relation, it
is seen, however, that these quantities are themselves algebraic functions of
the calculated core-particle amplitudes. For the deformed rare-earth nucleus
158Gd, we find that these sum rules are well-satisfied for the ground state
band, implying that we have found a self-consistent solution of the non-linear
Kerman-Klein equations.Comment: revtex and postscript, including 1 figure(postscript), submitted to
Phys.Rev.Let
Application of a semi-microscopic core-particle coupling method to the backbending in odd deformed nuclei
In two previous papers, the Kerman-Klein-Donau-Frauendorf (KKDF) model was
used to study rotational bands of odd deformed nuclei. Here we describe
backbending for odd nuclei using the same model. The backbending in the
neighboring even nuclei is described by a phenomenological two band model, and
this core is then coupled to a large single-particle space, as in our previous
work. The results obtained for energies and M1 transition rates are compared
with experimental data for 165Lu and for energies alone to the experimental
data for 179W. For the case of 165Lu comparison is also made with previous
theoretical work.Comment: 16 pages including 8 figure(postscript), submitted to Phys.Rev.
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