We have recently proposed a pre-quantum, pre-spacetime theory as a matrix-valued Lagrangian dynamics on an octonionic spacetime. This theory offers the prospect of unifying internal symmetries of the ...standard model with pre-gravitation. We explain why such a quantum gravitational dynamics is in principle essential even at energies much smaller than Planck scale. The dynamics can also predict the values of free parameters of the low-energy standard model: these parameters arising in the Lagrangian are related to the algebra of the octonions, which define the underlying non-commutative spacetime on which the dynamical degrees of freedom evolve. These free parameters are related to the exceptional Jordan algebra
J
3
(
8
)
, which describes the three fermion generations. We use the octonionic representation of fermions to compute the eigenvalues of the characteristic equation of this algebra and compare the resulting eigenvalues with known mass ratios for quarks and leptons. We show that the ratios of the eigenvalues correctly reproduce the square root of the known mass ratios. In conjunction with the trace dynamics Lagrangian, these eigenvalues also yield a theoretical derivation of the low-energy fine structure constant.
Abstract
There must exist a reformulation of quantum field theory, even at low energies, which does not depend on classical time. The octonionic theory proposes such a reformulation, leading to a ...pre-quantum pre-spacetime theory. The ingredients for constructing such a theory, which is also a unification of the standard model with gravitation, are : (i) the pre-quantum theory of trace dynamics – a matrix-valued Lagrangian dynamics, (ii) the spectral action principle of non-commutative geometry, (iii) the number system known as the octonions, for constructing a non-commutative manifold and for defining elementary particles via Clifford algebras, (iv) a Lagrangian with
E
8
×
E
8
symmetry. The split bioctonions define a sixteen dimensional space (with left-right symmetry) whose geometry (evolving in Connes time) relates to the four known fundamental forces, while predicting two new forces,
SU
(3)
grav
and
U
(1)
grav
. This latter interaction is possibly the theoretical origin of MOND. Coupling constants of the standard model result from left-right symmetry breaking, and their values are theoretically determined by the characteristic equation of the exceptional Jordan algebra of the octonions. The quantum-to-classical transition, precipitated by the entanglement of a critical number of fermions, is responsible for the emergence of classical spacetime, and also for the familiar formulation of quantum theory on a spacetime background.
Peripheral nerve injury or post-block neurological dysfunction (PBND) are uncommon but a recognized complications of peripheral nerve blocks (PNB). A broad range of its incidence is noted in the ...literature and hence a critical appraisal of its occurrence is needed.
In this review, we wanted to know the pooled estimates of PBND and further, determine its pooled estimates following various PNB over time. Additionally, we also sought to estimate the incidence of PBND with or without US guidance.
A literature search was conducted in six databases. For the purposes of the review, we defined PBND as any new-onset sensorimotor disturbances in the distribution of the performed PNB either attributable to the PNB (when reported) or reported in the context of the PNB (when association with a PNB was not mentioned). Both prospective and retrospective studies which provided incidence of PBND at timepoints of interest (>48 hours to <2 weeks; >2 weeks to 6 weeks, 7 weeks to 5 months, 6 months to 1 year and >1 year durations) were included for review. Incidence data were used to provide pooled estimates (with 95% CI) of PBND at these time periods. Similar estimates were obtained to know the incidence of PBND with or without the use of US guidance. Additionally, PBND associated with individual PNB were obtained in a similar fashion with upper and lower limb PNB classified based on the anatomical location of needle insertion.
The overall incidence of PBND decreased with time, with the incidence being approximately 1% at <2 weeks' time (Incidence per thousand (95% CI)= 9 (8; to 11)) to approximately 3/10 000 at 1 year (Incidence per thousand (95% CI)= 0. 3 (0.1; to 0.5)). Incidence of PBND differed for individual PNB with the highest incidence noted for interscalene block.
Our review adds information to existing literature that the neurological complications are rarer but seem to display a higher incidence for some blocks more than others. Use of US guidance may be associated with a lower incidence of PBND especially in those PNBs reporting a higher pooled estimates. Future studies need to standardize the reporting of PBND at various timepoints and its association to PNB.
The Karolyhazy uncertainty relation states that if a device is used to measure a length
l
, there will be a minimum uncertainty
δ
l
in the measurement, given by
(
δ
l
)
3
∼
L
P
2
l
. This is a ...consequence of combining the principles of quantum mechanics and general relativity. In this letter we show how this relation arises in our approach to quantum gravity, in a bottom-up fashion, from the matrix dynamics of atoms of space–time–matter. We use this relation to define a space–time–matter (STM) foam at the Planck scale, and to argue that our theory is holographic. By coarse graining over time-scales larger than Planck time, one obtains the laws of quantum gravity. Quantum gravity is not a Planck scale phenomenon; rather it comes into play whenever classical space–time background is not available to describe a quantum system. Space–time and classical general relativity arise from spontaneous localisation in a highly entangled quantum gravitational system. The Karolyhazy relation continues to hold in the emergent theory. An experimental confirmation of this relation will constitute a definitive test of the quantum nature of gravity.
Background
For the last 20 years, controversies in robotic surgery focused on cost reduction, development of new platforms and technologies, creation and validation of curriculum and virtual ...simulators, and conduction of randomized clinical trials to determine the best applications of robotics Leal Ghezzi and Campos in World J Surg 40:2550–2557, 2016.
Methods
This review explores the robotic systems which are currently indicated for use or development in gastrointestinal/abdominal surgery. These systems are reviewed and analyzed for clinical impact in these areas. In a MEDLINE search of articles with the search terms abdominal, gastrointestinal, review and robotic surgery, a total of 4306 total articles as of 2021 were assessed. Publicly available information, highest cited articles and reviews were assessed by the authors to determine the most significant regarding clinical outcomes.
Results
Despite this increased number of articles related to robotic surgery, ongoing controversies have led to limitation in the use of current and future robotic surgery platforms Connelly et al. in J Robotic Surg 14:155–165, 2020. Newer robotic platforms have limited studies or analysis that would allow meaningful definite conclusions. A multitude of new scenarios are possible due to this limited information.
Conclusion
Robotic surgery is in evolution to a larger conceptual field of computationally enhanced surgery (CES). Various terms have been used in the literature including computer-assisted surgery or digital Surgery Ranev and Teixeira in Surg Clin North Am 100:209–218, 2020. With the growth of technological changes inherent in CES, the ability to validate these improvements in outcomes will require new metrics and analytic tools. This learning feedback and metric analysis will generate the new opportunities in simulation, training and application Julian and Smith in Int J Med Robot 15:e2037, 2019.
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