Postoperative outcome in thoracolumbar spinal tuberculosis: a retrospective study

Background: Spinal tuberculosis is the most common location of extra pulmonary tuberculosis. ATT alone may not be suitable in all situations, especially when treating patients with risk of instability, progression of neurologic deficit, and failure of medical treatment. Surgical intervention is a major treatment modality for symptom relief in spinal tuberculosis.Methods: The aim of this study was to assess the immediate post-operative outcome in surgically treated patients with dorsolumbar spine tuberculosis at Department of Neurosurgery Government Medical College, Thrissur. All operated patients of dorsolumbar spinal tuberculosis during 2014 September to 2019 august were included under study.Results: A total of 57 patients were included in the study. The mean age of the patient was 42.77 years. There were 40 males (70.2%) and 17 females (29.8%). 55 (96.5%) out of 57 patients were having sensory symptoms. 41 (71.9%) out of 57 patients were having motor symptoms. Bladder involvement 23 (40.4%) and bowel involvement 15 (26.3%) were also noted in the study. Sensory symptoms improvement in post-operative period was noted in 46 (80.7%). Motor symptoms improvement was observed in 23 (56.1%) out of 41. Bladder symptoms improved in 6 (26.1%) out of 23. There is improvement in clinical symptoms, neurological function immediately after surgery. Surgical patients have faster improvement and can be mobilized earlier. Improvement in sensory symptoms (96.5%), motor symptoms (56.1%) and bladder symptoms (26.1%) were noted in our study in the immediate post-operative period.Conclusions: There was significant immediate relief in symptoms and morbidity of patients undergoing surgical treatment for dorsolumbar spine tuberculosis

Quantum metrology with Bose-Einstein condensates

We show how a generalized quantum metrology protocol can be implemented in a two-mode Bose-Einstein condensate of n atoms, achieving a sensitivity that scales better than 1/n and approaches 1/n^(3/2) for appropriate design of the condensate

Completely Positive Maps and Classical Correlations

We expand the set of initial states of a system and its environment that are known to guarantee completely positive reduced dynamics for the system when the combined state evolves unitarily. We characterize the correlations in the initial state in terms of its quantum discord [H. Ollivier and W. H. Zurek, Phys. Rev. Lett. 88, 017901 (2001)]. We prove that initial states that have only classical correlations lead to completely positive reduced dynamics. The induced maps can be not completely positive when quantum correlations including, but not limited to, entanglement are present. We outline the implications of our results to quantum process tomography experiments.Comment: 4 pages, 1 figur

Quantum-limited metrology with product states

We study the performance of initial product states of n-body systems in generalized quantum metrology protocols that involve estimating an unknown coupling constant in a nonlinear k-body (k << n) Hamiltonian. We obtain the theoretical lower bound on the uncertainty in the estimate of the parameter. For arbitrary initial states, the lower bound scales as 1/n^k, and for initial product states, it scales as 1/n^(k-1/2). We show that the latter scaling can be achieved using simple, separable measurements. We analyze in detail the case of a quadratic Hamiltonian (k = 2), implementable with Bose-Einstein condensates. We formulate a simple model, based on the evolution of angular-momentum coherent states, which explains the O(n^(-3/2)) scaling for k = 2; the model shows that the entanglement generated by the quadratic Hamiltonian does not play a role in the enhanced sensitivity scaling. We show that phase decoherence does not affect the O(n^(-3/2)) sensitivity scaling for initial product states.Comment: 15 pages, 6 figure

Lorentz transformations that entangle spins and entangle momenta

Simple examples are presented of Lorentz transformations that entangle the spins and momenta of two particles with positive mass and spin 1/2. They apply to indistinguishable particles, produce maximal entanglement from finite Lorentz transformations of states for finite momenta, and describe entanglement of spins produced together with entanglement of momenta. From the entanglements considered, no sum of entanglements is found to be unchanged.Comment: 5 Pages, 2 Figures, One new paragraph and reference adde

Single-electron quantum dot in Si/SiGe with integrated charge-sensing

Single-electron occupation is an essential component to measurement and manipulation of spin in quantum dots, capabilities that are important for quantum information processing. Si/SiGe is of interest for semiconductor spin qubits, but single-electron quantum dots have not yet been achieved in this system. We report the fabrication and measurement of a top-gated quantum dot occupied by a single electron in a Si/SiGe heterostructure. Transport through the quantum dot is directly correlated with charge-sensing from an integrated quantum point contact, and this charge-sensing is used to confirm single-electron occupancy in the quantum dot.Comment: 3 pages, 3 figures, accepted version, to appear in Applied Physics Letter

Quantum-limited metrology and Bose-Einstein condensates

We discuss a quantum-metrology protocol designed to estimate a physical parameter in a Bose-Einstein condensate of N atoms, and we show that the measurement uncertainty can decrease faster than 1/N. The 1/N scaling is usually thought to be the best possible in any measurement scheme. From the perspective of quantum information theory, we outline the main idea that leads to a measurement uncertainty that scales better than 1/N. We examine in detail some potential problems and challenges that arise in implementing such a measurement protocol using a Bose-Einstein condensate. We discuss how some of these issues can be dealt with by using lower-dimensional condensates trapped in nonharmonic potentials.Comment: 32 pages, 1 figure, updated reference

Sedimentary organic matter composition of Arctic Kongsfjorden sediments – A study emphasizing the biochemical composition and indices

1801-1809Kongsfjorden is a glacial fjord system influenced by the Atlantic and Arctic water masses. The spatial variability in the biochemical composition of the fjord sediments was studied during July 2016 and July 2017. The presence of the sedimentary Proteins, Carbohydrates and Lipid components was analyzed and studied with the support of biochemical indices and elemental ratios. The Kongsfjorden sedimentary system was dominated by the carbohydrate concentration in comparison with proteins and lipids. The labile fraction was maximum towards open ocean influenced by Atlantic water masses and minimum near to the glaciers. The fjord sediments were found to be enriched with an aged or degraded organic matter with a low quality labile organic matter

Quantum Metrology: Dynamics vs. Entanglement

A parameter whose coupling to a quantum probe of $n$ constituents includes all two-body interactions between the constituents can be measured with an uncertainty that scales as $1/n^{3/2}$, even when the constituents are initially unentangled. We devise a protocol that achieves the $1/n^{3/2}$ scaling without generating any entanglement among the constituents, and we suggest that the protocol might be implemented in a two-component Bose-Einstein condensate.Comment: 4 pages, 1 figur