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

River Discharge, in State of the Climate in 2008

The global mean temperature in 2008 was slightly cooler than that in 2007; however, it still ranks within the 10 warmest years on record. Annual mean temperatures were generally well above average in South America, northern and southern Africa, Iceland, Europe, Russia, South Asia, and Australia. In contrast, an exceptional cold outbreak occurred during January across Eurasia and over southern European Russia and southern western Siberia. There has been a general increase in land-surface temperatures and in permafrost temperatures during the last several decades throughout the Arctic region, including increases of 1° to 2°C in the last 30 to 35 years in Russia. Record setting warm summer (JJA) air temperatures were observed throughout Greenland

U.S. River Discharge for 2008 in State of the Climate in 2008

The global mean temperature in 2008 was slightly cooler than that in 2007; however, it still ranks within the 10 warmest years on record. Annual mean temperatures were generally well above average in South America, northern and southern Africa, Iceland, Europe, Russia, South Asia, and Australia. In contrast, an exceptional cold outbreak occurred during January across Eurasia and over southern European Russia and southern western Siberia. There has been a general increase in land-surface temperatures and in permafrost temperatures during the last several decades throughout the Arctic region, including increases of 1° to 2°C in the last 30 to 35 years in Russia. Record setting warm summer (JJA) air temperatures were observed throughout Greenland

Meron ground states of quantum Hall droplets

We argue that topological meron excitations, which are in a strong coupling phase (bound in pairs) in infinite quantum Hall ferromagnets, become deconfined in finite size quantum Hall systems. Although effectively for larger systems meron energy grows with the size of the system, when gyromagnetic ratio is small meron becomes the lowest lying state of a quantum Hall droplet. This comes as a consequence of the many-body correlations built in the meron construction that minimize the interaction energy. We demonstrate this by using mean field ansatzes for meron wave function. The ansatzes will enable us to consider much larger system sizes than in the previous work [A. Petkovic and M.V. Milovanovic, PRL 98, 066808 (2007)], where fractionalization into merons was introduced.Comment: 6 pages, 6 figure

Realistic Earth escape strategies for solar sailing

With growing interest in solar sailing comes the requirement to provide a basis for future detailed planetary escape mission analysis by drawing together prior work, clarifying and explaining previously anomalies. Previously unexplained seasonal variations in sail escape times from Earth orbit are explained analytically and corroborated within a numerical trajectory model. Blended-sail control algorithms, explicitly independent of time, which providenear-optimal escape trajectories and maintain a safe minimum altitude and which are suitable as a potential autonomous onboard controller, are then presented. These algorithms are investigated from a range of initial conditions and are shown to maintain the optimality previously demonstrated by the use of a single-energy gain control law but without the risk of planetary collision. Finally, it is shown that the minimum sail characteristic acceleration required for escape from a polar orbit without traversing the Earth shadow cone increases exponentially as initial altitude is decreased

Effect of Edge Roughness on Electronic Transport in Graphene Nanoribbon Channel Metal Oxide Semiconductor Field-Effect Transistors

Results of quantum mechanical simulations of the influence of edge disorder on transport in graphene nanoribbon metal oxide semiconductor field-effect transistors (MOSFETs) are reported. The addition of edge disorder significantly reduces ON-state currents and increases OFF-state currents, and introduces wide variability across devices. These effects decrease as ribbon widths increase and as edges become smoother. However the bandgap decreases with increasing width, thereby increasing the band-to-band tunneling mediated subthreshold leakage current even with perfect nanoribbons. These results suggest that without atomically precise edge control during fabrication, MOSFET performance gains through use of graphene will be difficult to achieve.Comment: 8 pages, 5 figure

Observability of counterpropagating modes at fractional-quantum-Hall edges

When the bulk filling factor is equal to 1 - 1/m with m odd, at least one counterpropagating chiral collective mode occurs simultaneously with magnetoplasmons at the edge of fractional-quantum-Hall samples. Initial experimental searches for an additional mode were unsuccessful. In this paper, we address conditions under which its observation should be expected in experiments where the electronic system is excited and probed by capacitive coupling. We derive realistic expressions for the velocity of the slow counterpropagating mode, starting from a microscopic calculation which is simplified by a Landau-Silin-like separation between long-range Hartree and residual interactions. The microscopic calculation determines the stiffness of the edge to long-wavelength neutral excitations, which fixes the slow-mode velocity, and the effective width of the edge region, which influences the magnetoplasmon dispersion.Comment: 18 pages, RevTex, 6 figures, final version to be published in Physical Review

Electron spin and charge switching in a coupled quantum dot quantum ring system

Few-electron systems confined in a quantum dot laterally coupled to a surrounding quantum ring in the presence of an external magnetic field are studied by exact diagonalization. The distribution of electrons between the dot and the ring is influenced by the relative strength of the dot and ring confinement, the gate voltage and the magnetic field which induces transitions of electrons between the two parts of the system. These transitions are accompanied by changes in the periodicity of the Aharonov-Bohm oscillations of the ground-state angular momentum. The singlet-triplet splitting for a two electron system with one electron confined in the dot and the other in the ring exhibits piecewise linear dependence on the external field due to the Aharonov-Bohm effect for the ring-confined electron, in contrast to smooth oscillatory dependence of the exchange energy for laterally coupled dots in the side-by-side geometry.Comment: to appear in PRB in August 200

Statistics of real eigenvalues in Ginibre's Ensemble of random real matrices

The integrable structure of Ginibre's orthogonal ensemble of random matrices is looked at through the prism of the probability pn,k to find exactly k real eigenvalues in the spectrum of an n×n real asymmetric Gaussian random matrix. The exact solution for the probability function pn,k is presented, and its remarkable connection to the theory of symmetric functions is revealed. An extension of the Dyson integration theorem is a key ingredient of the theory presented