15,808 research outputs found
Mixing of Xi_c and Xi_c' Baryons
The mixing angle between the Xi_c and Xi_c' baryons is shown to be small,
with a negligible shift in the Xi_c masses.Comment: One missprint corrected. The numerator of Eq. (12) should read
{2[(Sigma_c^{*++}-Sigma_c^{++})-(Xi_c^{*+}-Xi_c^{'+})]} The correct equation
was used in the calculation so no other change is mad
Lorentz contraction, Bell's spaceships, and rigid body motion in special relativity
The meaning of Lorentz contraction in special relativity and its connection
with Bell's spaceships parable is discussed. The motion of Bell's spaceships is
then compared with the accelerated motion of a rigid body. We have tried to
write this in a simple form that could be used to correct students'
misconceptions due to conflicting earlier treatments.Comment: Modified the discussion in Sec. 2. This version to be published in
European Journal of Physic
Mesoscopic one-way channels for quantum state transfer via the Quantum Hall Effect
We show that the one-way channel formalism of quantum optics has a physical
realisation in electronic systems. In particular, we show that magnetic edge
states form unidirectional quantum channels capable of coherently transporting
electronic quantum information. Using the equivalence between one-way photonic
channels and magnetic edge states, we adapt a proposal for quantum state
transfer to mesoscopic systems using edge states as a quantum channel, and show
that it is feasible with reasonable experimental parameters. We discuss how
this protocol may be used to transfer information encoded in number, charge or
spin states of quantum dots, so it may prove useful for transferring quantum
information between parts of a solid-state quantum computer.Comment: 4 pages, 3 figure
The Effect of Propranolol and Midazolam on the Reconsolidation of a Morphine Place Preference in Chronically Treated Rats
A stable memory can be disrupted if amnestic treatment is applied in conjunction with memory reactivation. Recent findings in the conditioned place preference (CPP) model suggest that blocking reconsolidation attenuates the ability of environmental cues to induce craving and relapse in drug addicts, but the impact of prior physical dependence has not been described. We examined the effect of post-reactivation amnestic treatment on reconsolidation of a CPP for morphine, in animals naïve to morphine, under chronic morphine experience or abstinent. Chronic morphine experience was induced by escalating doses of morphine from 10 mg/kg/day (s.c.), and maintained on 30 mg/kg/day during the course of conditioning and reactivation procedures, or conditioning alone. Naïve and morphine-experienced animals were trained in a three-compartment apparatus by four morphine (5 mg/kg, s.c.) and four saline experiences paired with either of two large conditioning compartments. The memory was then reactivated by a CPP test, and immediately afterward animals received an injection of the beta-adrenergic antagonist propranolol (10 mg/kg, s.c.), the GABAa agonist midazolam (1 mg/kg, i.p.), or saline. Morphine-naïve rats received only a single reconsolidation-blocking treatment (Experiment 1), while chronic morphine rats were given eight reactivation sessions each followed by amnestic treatment, either before (Experiment 2) or after 10 days of withdrawal (Experiment 3). Propranolol and midazolam disrupted reconsolidation in morphine-naïve rats, but failed to disrupt the CPP when rats were trained under chronic morphine treatment, even if they were recovered from chronic opiate exposure before reactivation. In fact, propranolol increased the preference for the drug-paired context in animals trained while maintained on chronic morphine. Midazolam had little effect. Morphine experience may produce neurochemical changes which alter memory storage processes and reduce the impact of amnestic treatments on reconsolidation
Addressing student models of energy loss in quantum tunnelling
We report on a multi-year, multi-institution study to investigate student
reasoning about energy in the context of quantum tunnelling. We use ungraded
surveys, graded examination questions, individual clinical interviews, and
multiple-choice exams to build a picture of the types of responses that
students typically give. We find that two descriptions of tunnelling through a
square barrier are particularly common. Students often state that tunnelling
particles lose energy while tunnelling. When sketching wave functions, students
also show a shift in the axis of oscillation, as if the height of the axis of
oscillation indicated the energy of the particle. We find inconsistencies
between students' conceptual, mathematical, and graphical models of quantum
tunnelling. As part of a curriculum in quantum physics, we have developed
instructional materials to help students develop a more robust and less
inconsistent picture of tunnelling, and present data suggesting that we have
succeeded in doing so.Comment: Originally submitted to the European Journal of Physics on 2005 Feb
10. Pages: 14. References: 11. Figures: 9. Tables: 1. Resubmitted May 18 with
revisions that include an appendix with the curriculum materials discussed in
the paper (4 page small group UW-style tutorial
Lembaga Pemasyarakatan Kelas 1 di Manado. Teori Gestalt dalam Arsitektur
Negara Indonesia yang berdasarkan Pancasila membuka pemikiran- pemikiran baru mengenai fungsi pembinaan yang tidak lagi sekedar penjaraan tetapi juga merupakan suatu USAha rehabilitasi dan reintegrasi sosial Warga Binaan Pemasyarakatan (WBP). Beberapa fenomena yang menjadi kendala bagi sistem pembinaan dan pembimbingan di lembaga pemasyarakatan sampai saat ini belum mendapat titik penyelesaian, sehingga penilaian masyarakat terhadap lembaga pemasyarakatan tidak ada bedanya dengan penjara membuat mantan narapidana sulit diterima oleh masyarakat. Lembaga Pemasyarakatan (Lapas) atau dalam bahasa masyarakat awam disebut penjara,merupakan tempa/kediaman bagi orang-orang yang bermasalah dngan hukum.Penerapan teori gestalt terhadap bangunan dapat menghasilkan konsep baru bagi desain lapasLuas site yang akan di bangun 38.417 m2,BCR bangunan 26,443.9m2 dalam kawasan terdapat 11 masa bangunan,terdiri dari masa perkantoran ,rg.kunjungan,dapur,poliklinik,workshop,aula,hunian umum,narkoba dan tipikor.Dengan ketinggian lantai berfariasi tergantung kebutuhan.Untuk mencapai bangunan tujuan bangunan lapas yang dapat memanusiakan manusia di terapkan 2 hukum gestalt yaitu hukum similarity atau kelarasan pada fasade bangunan dan hukum ketertutupan pada konsep layout
Intrinsic thermal vibrations of suspended doubly clamped single-wall carbon nanotubes
We report the observation of thermally driven mechanical vibrations of
suspended doubly clamped carbon nanotubes, grown by chemical vapor deposition
(CVD). Several experimental procedures are used to suspend carbon nanotubes.
The vibration is observed as a blurring in images taken with a scanning
electron microscope. The measured vibration amplitudes are compared with a
model based on linear continuum mechanics.Comment: pdf including figures, see:
http://www.unibas.ch/phys-meso/Research/Papers/2003/NT-Thermal-Vibrations.pd
The condensin complexes play distinct roles to ensure normal chromosome morphogenesis during meiotic division in Arabidopsis
Meiosis is a specialized cell division essential for sexual reproduction. During meiosis the chromosomes are highly organized, and correct chromosome architecture is required for faithful segregation of chromosomes at anaphase I and II. Condensin is involved in chromosome organization during meiotic and mitotic cell divisions. Three condensin subunits, AtSMC4 and the condensin I and II specific subunits AtCAP-D2 and AtCAP-D3, respectively, have been studied for their role in meiosis. This has revealed that both the condensin I and condensin II complexes are required to maintain normal structural integrity of the meiotic chromosomes during the two nuclear divisions. Their roles appear functionally distinct in that condensin I is required to maintain normal compaction of the centromeric repeats and 45S rDNA, whereas loss of condensin II was associated with extensive interchromosome connections at metaphase I. Depletion of condensin is also associated with a slight reduction in crossover formation, suggesting a role during meiotic prophase I
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