PubMed Health⌕ Search

PubMed · 7326377

Changing fetal position through maternal posturing.

Abstract

Two completed studies and a study in progress have addressed the question whether maternal posturing can produce the rotation of a fetus from a posterior or transverse position to the optimal anterior position. There are clinical problems associated with a malposition and also with the therapeutic procedures used to correct the malposition. Maternal posturing is considered safe, simple, economic, and noninvasive. There is a sound rationale for the choice of the hands and knees posture and the variations used to facilitate fetal rotation. Two studies indicate the effectiveness of maternal posturing. The physical theories of gravity, buoyancy, and friction are used to explain the postures, the fetus, and fetal rotation. The results of the second study are explained with the same physical theories. A current study about maternal postures and fetal position is in progress.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

C M Andrews. 1981. Changing fetal position through maternal posturing.. https://pubmed.ncbi.nlm.nih.gov/7326377/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

High-pressure transformations in xenon hydrates.

A high-pressure investigation of the Xe*H(2)O chemical system was conducted by using diamond-anvil cell techniques combined with in situ Raman spectroscopy, synchrotron x-ray diffraction, and laser heating. Structure I xenon clathrate was observed to be stable up to 1.8 GPa, at which pressure it transforms to a new Xe clathrate phase stable up to 2.5 GPa before breaking down to ice VII plus solid xenon. The bulk modulus and structure of both phases were determined: 9 +/- 1 GPa for Xe clathrate A with structure I (cubic, a = 11.595 +/- 0.003 A, V = 1,558.9 +/- 1.2 A(3) at 1.1 GPa) and 45 +/- 5 GPa for Xe clathrate B (tetragonal, a = 8.320 +/- 0.004 A, c = 10.287 +/- 0.007 A, V = 712.1 +/- 1.2 A(3) at 2.2 GPa). The extended pressure stability field of Xe clathrate structure I (A) and the discovery of a second Xe clathrate (B) above 1.8 GPa have implications for xenon in terrestrial and planetary interiors.

Biophysical Phenomena↗

Definition of the rheological glass transition temperature in association with the concept of iso-free-volume.

Small deformation dynamic oscillation was used to develop an index of physical significance for the rationalisation of the mechanical properties of high co-solute/biopolymer systems during vitrification. The index is based on the combined framework of Williams-Landel-Ferry equation with the free volume theory and is called the 'rheological glass transition temperature, T(g)' thus differentiating it from the empirical calorimetric T(g) used in thermal analysis. The rheological T(g) is located at the conjunction of two distinct molecular processes, namely: free-volume effects in the glass transition region and the predictions of the reaction-rate theory in the glassy state. The method of reduced variables was used to shift the mechanical spectra of shear moduli to composite curves. The temperature dependence of shift factors for all materials was identical provided that they were normalised at suitably different reference temperatures, which reflect iso-free-volume states. The treatment makes free volume the overriding parameter governing the mechanical relaxation times during vitrification of high co-solute/biopolymer systems regardless of physicochemical characteristics. We believe that potential applications resulting from this fundamental work are numerous for the food and pharmaceutical industries.

Biophysical Phenomena↗

Cavity approach to noisy learning in nonlinear perceptrons.

We analyze the learning of noisy teacher-generated examples by nonlinear and differentiable student perceptrons using the cavity method. The generic activation of an example is a function of the cavity activation of the example, which is its activation in the perceptron that learns without the example. Mean-field equations for the macroscopic parameters and the stability condition yield results consistent with the replica method. When a single value of the cavity activation maps to multiple values of the generic activation, there is a competition in learning strategy between preferentially learning an example and sacrificing it in favor of the background adjustment. We find parameter regimes in which examples are learned preferentially or sacrificially, leading to a gap in the activation distribution. Full phase diagrams of this complex system are presented, and the theory predicts the existence of a phase transition from poor to good generalization states in the system. Simulation results confirm the theoretical predictions.

Biophysical Phenomena↗