32,121 research outputs found
High Resolution Ionization of Ultracold Neutral Plasmas
Collective effects, such as waves and instabilities, are integral to our
understanding of most plasma phenomena. We have been able to study these in
ultracold neutral plasmas by shaping the initial density distribution through
spatial modulation of the ionizing laser intensity. We describe a relay imaging
system for the photoionization beam that allows us to create higher resolution
features and its application to extend the observation of ion acoustic waves to
shorter wavelengths. We also describe the formation of sculpted density
profiles to create fast expansion of plasma into vacuum and streaming plasmas
String Representation of Quantum Loops
We recover a general representation for the quantum state of a relativistic
closed line (loop) in terms of string degrees of freedom.The general form of
the loop functional splits into the product of the Eguchi functional, encoding
the holographic quantum dynamics, times the Polyakov path integral, taking into
account the full Bulk dynamics, times a loop effective action, which is needed
to renormalize boundary ultraviolet divergences. The Polyakov string action is
derived as an effective actionfrom a phase space,covariant,Schild action, by
functionally integrating out the world-sheet coordinates.The area coordinates
description of the boundary quantum dynamics, is shown to be induced by the
``zero mode'' of the bulk quantum fluctuations. Finally, we briefly comment
about a ``unified, fully covariant'' description of points, loops and strings
in terms of Matrix Coordinates.Comment: 16 Pages, RevTeX, no figure
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The Differences in Antibiotic Decision-making Between Acute Surgical and Acute Medical Teams: An Ethnographic Study of Culture and Team Dynamics
Background
Cultural and social determinants influence antibiotic decision-making in hospitals. We investigated and compared cultural determinants of antibiotic decision-making in acute medical and surgical specialties.
Methods
An ethnographic observational study of antibiotic decision-making in acute medical and surgical teams at a London teaching hospital was conducted (August 2015–May 2017). Data collection included 500 hours of direct observations, and face-to-face interviews with 23 key informants. A grounded theory approach, aided by Nvivo 11 software, analyzed the emerging themes. An iterative and recursive process of analysis ensured saturation of the themes. The multiple modes of enquiry enabled cross-validation and triangulation of the findings.
Results
In medicine, accepted norms of the decision-making process are characterized as collectivist (input from pharmacists, infectious disease, and medical microbiology teams), rationalized, and policy-informed, with emphasis on de-escalation of therapy. The gaps in antibiotic decision-making in acute medicine occur chiefly in the transition between the emergency department and inpatient teams, where ownership of the antibiotic prescription is lost. In surgery, team priorities are split between 3 settings: operating room, outpatient clinic, and ward. Senior surgeons are often absent from the ward, leaving junior staff to make complex medical decisions. This results in defensive antibiotic decision-making, leading to prolonged and inappropriate antibiotic use.
Conclusions
In medicine, the legacy of infection diagnosis made in the emergency department determines antibiotic decision-making. In surgery, antibiotic decision-making is perceived as a nonsurgical intervention that can be delegated to junior staff or other specialties. Different, bespoke approaches to optimize antibiotic prescribing are therefore needed to address these specific challenges
Sistema silvipastoril e pastagem exclusiva de braquiária para recria de novilhas leiteiras: massa de forragem, qualidade do pasto, consumo e ganho de peso.
bitstream/item/89793/1/BOP-20.pd
Boas práticas para a implantação de sistemas silvipastoris.
bitstream/item/44226/1/COT-50.pd
Applications of quantum integrable systems
We present two applications of quantum integrable systems. First, we predict
that it is possible to generate high harmonics from solid state devices by
demostrating that the emission spectrum for a minimally coupled laser field of
frequency to an impurity system of a quantum wire, contains multiples
of the incoming frequency. Second, evaluating expressions for the conductance
in the high temperature regime we show that the caracteristic filling fractions
of the Jain sequence, which occur in the fractional quantum Hall effect, can be
obtained from quantum wires which are described by minimal affine Toda field
theories.Comment: 25 pages of LaTex, 4 figures, based on talk at the 6-th international
workshop on conformal field theories and integrable models, (Chernogolovka,
September 2002
Topological Defects and the Spin Glass Phase of Cuprates
We propose that the spin glass phase of cuprates is due to the proliferation
of topological defects of a spiral distortion of the antiferromagnet order. Our
theory explains straightforwardly the simultaneous existence of short range
incommensurate magnetic correlations and complete a-b symmetry breaking in this
phase. We show via a renormalization group calculation that the collinear
O(3)/O(2) symmetry is unstable towards the formation of local non-collinear
correlations. A critical disorder strength is identified beyond which
topological defects proliferate already at zero temperature.Comment: 7 pages, 2 figures. Final version with some changes and one replaced
figur
An alternative approach for the dynamics of polarons in one dimension
We developed a new method based on functional integration to treat the
dynamics of polarons in one-dimensional systems. We treat the acoustical and
the optical case in an unified manner, showing their differences and
similarities. The mobility and diffusion coefficients are calculated in the
Markovian approximation in the strong coupling limit.Comment: 57 page
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