Neonatal weight loss in breast and formula-fed infants

We have observed an increase in the number of breast fed babies presenting with dehydration and/or failure to thrive because of lactation failure and non-recognition of feeding problems. Recent reports1,2 support this experience and recommend monitoring of the weight of infants through the neonatal period. However, these reports acknowledge uncertainty as to what actually constitutes normal neonatal weight loss. Maisels and colleagues published two studies which have been quoted as giving guidance on normal loss. Both studies were designed primarily to study factors that influence breast milk jaundice. The first3 reported a mean weight loss of about 6% in 100 unselected well babies during the first 3 days. The subsequent study4 reported a mean weight loss of 6.86% in 186 infants. The timescale over which babies were weighed was not clearly indicated, although it may have only been 2-3 days. The sample was neither population based nor randomly selected, being largely preselected because of the presence of more pronounced jaundice. The distribution of data points for early neonatal weight loss are likely to be skewed, yet both studies reported the results as mean (SD). Owing to the design and method of data presentation, these studies cannot reliably inform the debate as to what constitutes the norm. Marchini and colleagues published reports also designed primarily to study other issues. One5 indicated a mean early weight loss of 5.7%. Measurements were recorded over a three day period, and no indication is given of the skewness of the data. Another study6 reported a median weight loss of about 6% recorded over a four day period. At least one baby lost > 15% of his/her birth weight during this time, but there is no clear information as to the frequency with which more extreme degrees of weight loss are observed

Collective Spin-Density-Wave Response Perpendicular to the Chains of the Quasi One-Dimensional Conductor (TMTSF)2PF6

Microwave experiments along all three directions of the spin-density-wave model compound (TMTSF)$_2$PF$_6$ reveal that the pinned mode resonance is present along the $a$ and $b^{\prime}$ axes. The collective transport is considered to be the fingerprint of the condensate. In contrast to common quasi one-dimensional models, the density wave also slides in the perpendicular $b^{\prime}$ direction. The collective response is absent along the least conducting $c^*$ direction.Comment: 3 pages, 4 figure

Measuring unsteady pressure on rotating compressor blades

Miniature semiconductor strain gage pressure transducers mounted in several arrangements were studied. Both surface mountings and recessed flush mountings were tested. Test parameters included mounting arrangement, blade material, temperature, local strain in the acceleration normal to the transducer diaphragm, centripetal acceleration, and pressure. Test results show no failures of transducers or mountings and indicate an uncertainty of unsteady pressure measurement of approximately + or - 6 percent + 0.1 kPa for a typical application. Two configurations were used on a rotating fan flutter program. Examples of transducer data and correction factors are presented

Genetic alterations and cancer formation in a European flatfish at sites of different contamination burdens

Fish diseases are an indicator for marine ecosystem health since they provide a biological end-point of historical exposure to stressors. Liver cancer has been used to monitor the effects of exposure to anthropogenic pollution in flatfish for many years. The prevalence of liver cancer can exceed 20%. Despite the high prevalence and the opportunity of using flatfish to study environmentally induced cancer, the genetic and environmental factors driving tumor prevalence across sites are poorly understood. This study aims to define the link between genetic deterioration, liver disease progression, and anthropogenic contaminant exposures in the flatfish dab (Limanda limanda). We assessed genetic changes in a conserved cancer gene, Retinoblastoma (Rb), in association with histological diagnosis of normal, pretumor, and tumor pathologies in the livers of 165 fish from six sites in the North Sea and English Channel. The highest concentrations of metals (especially cadmium) and organic chemicals correlated with the presence of tumor pathology and with defined genetic profiles of the Rb gene, from these sites. Different Rb genetic profiles were found in liver tissue near each tumor phenotype, giving insight into the mechanistic molecular-level cause of the liver pathologies. Different Rb profiles were also found at sampling sites of differing contaminant burdens. Additionally, profiles indicated that histological “normal” fish from Dogger sampling locations possessed Rb profiles associated with pretumor disease. This study highlights an association between Rb and specific contaminants (especially cadmium) in the molecular etiology of dab liver tumorigenesis

Time dependent diffusion in a disordered medium with partially absorbing walls: A perturbative approach

We present an analytical study of the time dependent diffusion coefficient in a dilute suspension of spheres with partially absorbing boundary condition. Following Kirkpatrick (J. Chem. Phys. 76, 4255) we obtain a perturbative expansion for the time dependent particle density using volume fraction $f$ of spheres as an expansion parameter. The exact single particle $t$-operator for partially absorbing boundary condition is used to obtain a closed form time-dependent diffusion coefficient $D(t)$ accurate to first order in the volume fraction $f$. Short and long time limits of $D(t)$ are checked against the known short-time results for partially or fully absorbing boundary conditions and long-time results for reflecting boundary conditions. For fully absorbing boundary condition the long time diffusion coefficient is found to be $D(t)=5 a^2/(12 f D_{0} t) +O((D_0t/a^2)^{-2})$, to the first order of perturbation theory. Here $f$ is small but non-zero, $D_0$ the diffusion coefficient in the absence of spheres, and $a$ the radius of the spheres. The validity of this perturbative result is discussed

Evolution from a molecular Rydberg gas to an ultracold plasma in a seeded supersonic expansion of NO

We report the spontaneous formation of a plasma from a gas of cold Rydberg molecules. Double-resonant laser excitation promotes nitric oxide, cooled to 1 K in a seeded supersonic molecular beam, to single Rydberg states extending as deep as 80 cm$^{-1}$ below the lowest ionization threshold. The density of excited molecules in the illuminated volume is as high as 1 x 10$^{13}$ cm$^{-3}$. This population evolves to produce prompt free electrons and a durable cold plasma of electrons and intact NO$^{+}$ ions.Comment: 4 pages (two column) 3 figures; smaller figure files, corrected typo