Lumbar puncture for the generalist

The safe and successful performance of a lumbar puncture demands a working and yet specific knowledge as well as competency in performance. This review aims to aid understanding of the knowledge framework, the pitfalls and complications of lumbar puncture. It includes special reference to three dimensional relationships, functional anatomy, imaging anatomy, normal variation and living anatomy. A lumbar puncture is a commonly performed procedure for diagnostic and therapeutic purposes. Epidural and spinal anaesthesia, for example, are common in obstetric practice and involve the same technique as a lumbar puncture except for the endpoint of the needle being in the epidural space and subarachnoid space respectively. The procedure is by no means innocuous and some anatomical pitfalls include inability to find the correct entry site for placement of the lumbar puncture needle and lack of awareness of structures in relation to the advancing needle. Headache is the most common complication and it is important to avoid traumatic and dry taps, herniation syndromes and injury to the terminal end of the spinal cord. With a thorough knowledge of the contraindications, the regional anatomy and rationale of the technique and adequate prior skills practice, a lumbar puncture can be performed safely and successfully

Quasiparticles beyond the Fermi liquid and heavy fermion criticality

We give a self-consistent theory of the scale dependent effective mass enhancement m*/m of quasiparticles by 3D antiferromagnetic (AFM) spin fluctuations in the presence of disorder at an AFM quantum critical point. The coupling of fermionic and bosonic degrees of freedom in the critical regime is described in terms of a critical quasiparticle theory. Using the fact that even in the "non-Fermi liquid" regime the quasiparticle width does not exceed the quasiparticle energy, we adopt relations from Fermi liquid theory to determine the dependence of the spin fluctuation spectrum on m*/m, from which the self energy and hence m*/m may be calculated. The self-consistent equation for m*/m has a strong coupling solution provided the initial value is sufficiently large. We argue that in YbRh2Si2, quasi-2D Gaussian fluctuations existing over a wide range drive the system into the 3D strongly coupled fluctuation regime. We find critical exponents of the temperature dependence of the specific heat coefficient \gamma\propto T^{-1/4} and of the resistivity \rho(T)=\rho(0)+ A T^{3/4} in good agreement with experiments on YbRh2Si2 in the temperature range T < 0.3K.Comment: 3 figures. Revised references and slight changes in wording. Results unchange

Synthesis and characterization of an oxo-bridged rhenium(V) complex with an amine-phenol tetradentate ligand

The oxo-bridged dinuclear complex [(μ-O){ReO(sal2hpn)}2].EtOH was prepared by the reaction of trans-[ReOCl3(PPh3)2] with N,N’-propylenebis(salicylideneamine) (H2sal2hpn) in ethanol. An X-ray crystallographic study showed that each sal2hpn is coordinated as a tetradentate dianionic chelate. The axis of the molecule is formed by the O=Re-O-Re=O moiety, with the average O=Re-O and Re-O-Re bond angles equal to 165.2(2)° and 164.8(2)° respectively. The average Re=O bond equals 1.697(5) Å, and the Re-O bonds have an average length of 1.928(4) Å. The structure has a monoclinic space group Cc with a = 13.7747(2) Å, b = 26.8715(4) Å, c = 9.6478(1) Å, β = 92.4202(9)°, V = 3567.92(8) Å3 and Z = 4.   KEY WORDS: Oxo-bridge, Rhenium(V), Dimeric, Crystal structure  Bull. Chem. Soc. Ethiop. 2007, 21(1), 83-88.

The collision of boosted black holes

We study the radiation from a collision of black holes with equal and opposite linear momenta. Results are presented from a full numerical relativity treatment and are compared with the results from a ``close-slow'' approximation. The agreement is remarkable, and suggests several insights about the generation of gravitational radiation in black hole collisions.Comment: 8 pages, RevTeX, 3 figures included with eps