Polarization proximity effect in isolator crystal pairs

We experimentally studied the polarization dynamics (orientation and ellipticity) of near infrared light transmitted through magnetooptic Yttrium Iron Garnet crystal pairs using a modified balanced detection scheme. When the pair separation is in the sub-millimeter range, we observed a proximity effect in which the saturation field is reduced by up to 20%. 1D magnetostatic calculations suggest that the proximity effect originates from magnetostatic interactions between the dipole moments of the isolator crystals. This substantial reduction of the saturation field is potentially useful for the realization of low-power integrated magneto-optical devices.Comment: submitted to Optics Letter

The impact of significant input of fine sediment on benthic fauna at tributary junctions: a case study of the Bermejo-Paraguay River confluence, Argentina

This study examines the morphological features, suspended sediment inputs and hydraulic conditions within a large river in association with ecological patterns before and after a tributary confluence. In order to examine these effects, the macroinvertebrate distributions from three reaches of the Paraguay and Bermejo Rivers (Paraguay-Argentina) are investigated. The Bermejo River is a tributary that supplies significant quantities of fine sediment to the Paraguay River, primarily in suspension. Two reaches were examined on the Paraguay River, upstream and downstream of the Bermejo River junction, with the third study reach located on the Bermejo River, upstream of the confluence with the Paraguay River. The results provide clear evidence that a significantly increased loading of fine sediment at a river confluence has effects on the distribution and potential movement of benthic invertebrates in the lotic environment by representing physical barriers at affected sites. These effects may be important at both local and regional scales, and such increases in suspended sediment (especially associated with anthropogenic change) may thus pose a major threat to ecosystem integrity that has been historically underestimated

National survey of pediatric services available in US emergency departments

BACKGROUND: Children account for nearly 20% of all US emergency department (ED) visits, yet previous national surveys found that many EDs lack specialized pediatric care. In response, a 2001 joint policy statement recommended resources needed by EDs for effective pediatric emergency care delivery. We sought to update and enhance previous estimates of pediatric services available in US EDs. METHODS: We administered a telephone survey to a 5% random sample (n = 279) of all US EDs from the 2007 National Emergency Department Inventory-USA. The survey collected data on local capabilities (including typical management of three clinical scenarios) and prevalence of a coordinator for pediatric emergency care. We used descriptive statistics to summarize data. Multivariable logistic regression was used to examine the association between survey respondent and ED characteristics as well as the presence of a coordinator for pediatric emergency medicine. RESULTS: Data were collected from 238 hospitals (85% response rate). A minority of hospitals had pediatric departments (36%) or intensive care units (12%). The median annual number of ED visits by children was 3,870 (interquartile range 1,500–8,800). Ten percent of hospitals had a separate pediatric ED; only 17% had a designated pediatric emergency care coordinator. Significant positive predictors of a coordinator were an ED pediatric visit volume of ≥1 patient per hour and urban location. Most EDs treated only mild-to-moderate cases of childhood bronchiolitis and asthma exacerbation (77% and 65%, respectively). Less than half (48%) of the hospitals reported the ability to surgically manage a child with acute appendicitis. CONCLUSION: We found little change in pediatric emergency services compared to earlier estimates. Our study results suggest a continued need for improvements to ensure access to emergency care for children

Coeficiente de cultura e produtividade da mangueira irrigada.

Data of solar radiation, soil heat flux and dry and wet bulbs air temperature were used in the elaboration of theabove canopy energy balance based on Bowen ratio. Also, data soil humidity profiles were used in thedetermination of the soil water balance of a dripping irrigated seven years old mango orchard, cv. ?Tommy Atkins’.The field experiment was conducted in the irrigated perimeter of Bebedouro, in Petrolina-PE, Brazil (Latitude:09009`S, Longitude: 40022`W; altitude: 365.5m), in the years of 1998 and 1999. The obtained results indicatedthat, in the submedian San Francisco river region soil and climate conditions, the mango orchard waterconsumption, represented by the corp coefficient (Kc), doesn't stay constant throughout the productive cycle, but itvaries as a function of the days after flowering(DAF) according to the following equation: Kc = 0.36 + 0.009(DAF) – 4.0 x 10-5 (DAF)2, with r2 = 0.79

Balanco hidrico no solo cultivado com mangueiras.

The experimental part of the present research was conducted in the irrigated perimeter of Bebedouro, Petrolina, PE,Brazil (Latitude: 09009`S, Longitude: 40022`W; altitude: 365.5m) in the years of 1998 and 1999, in a drippingirrigated plot area of 9,880 m2 seven years old mango orchard, cv. ?Tommy Atkins`, planted in a spacing of 5mbetween plants by 8m between arrays. This work evaluated the efficiency of the soil water balance for determiningthe evapotranspiraration throughout the mango orchard productive cycle. The errors analysis indicated that, for thesubmedian San Francisco river region soil and climate conditions, the soil water balance method for estimatingevapotranspiration should not be applied for periods lower than a week. Also, according to the obtained results, thesoil water balance method is only efficient in the estimates of the evapotranspiration of mango orchard whenconsidering the term regarding to the deep drainage or water ascent

Mid-infrared optical parametric amplifier using silicon nanophotonic waveguides

All-optical signal processing is envisioned as an approach to dramatically decrease power consumption and speed up performance of next-generation optical telecommunications networks. Nonlinear optical effects, such as four-wave mixing (FWM) and parametric gain, have long been explored to realize all-optical functions in glass fibers. An alternative approach is to employ nanoscale engineering of silicon waveguides to enhance the optical nonlinearities by up to five orders of magnitude, enabling integrated chip-scale all-optical signal processing. Previously, strong two-photon absorption (TPA) of the telecom-band pump has been a fundamental and unavoidable obstacle, limiting parametric gain to values on the order of a few dB. Here we demonstrate a silicon nanophotonic optical parametric amplifier exhibiting gain as large as 25.4 dB, by operating the pump in the mid-IR near one-half the band-gap energy (E~0.55eV, lambda~2200nm), at which parasitic TPA-related absorption vanishes. This gain is high enough to compensate all insertion losses, resulting in 13 dB net off-chip amplification. Furthermore, dispersion engineering dramatically increases the gain bandwidth to more than 220 nm, all realized using an ultra-compact 4 mm silicon chip. Beyond its significant relevance to all-optical signal processing, the broadband parametric gain also facilitates the simultaneous generation of multiple on-chip mid-IR sources through cascaded FWM, covering a 500 nm spectral range. Together, these results provide a foundation for the construction of silicon-based room-temperature mid-IR light sources including tunable chip-scale parametric oscillators, optical frequency combs, and supercontinuum generators

Water consumption and energy balance in mango tree orchard at a tropiccal station.

Otherwise it includes both quantity of water a tree uses and the timing of water applications

Common carotid intima media thickness and ankle-brachial pressure index correlate with local but not global atheroma burden:a cross sectional study using whole body magnetic resonance angiography

Common carotid intima media thickness (CIMT) and ankle brachial pressure index (ABPI) are used as surrogate marker of atherosclerosis, and have been shown to correlate with arterial stiffness, however their correlation with global atherosclerotic burden has not been previously assessed. We compare CIMT and ABPI with atheroma burden as measured by whole body magnetic resonance angiography (WB-MRA).50 patients with symptomatic peripheral arterial disease were recruited. CIMT was measured using ultrasound while rest and exercise ABPI were performed. WB-MRA was performed in a 1.5T MRI scanner using 4 volume acquisitions with a divided dose of intravenous gadolinium gadoterate meglumine (Dotarem, Guerbet, FR). The WB-MRA data was divided into 31 anatomical arterial segments with each scored according to degree of luminal narrowing: 0 = normal, 1 = <50%, 2 = 50-70%, 3 = 70-99%, 4 = vessel occlusion. The segment scores were summed and from this a standardized atheroma score was calculated.The atherosclerotic burden was high with a standardised atheroma score of 39.5±11. Common CIMT showed a positive correlation with the whole body atheroma score (β 0.32, p = 0.045), however this was due to its strong correlation with the neck and thoracic segments (β 0.42 p = 0.01) with no correlation with the rest of the body. ABPI correlated with the whole body atheroma score (β -0.39, p = 0.012), which was due to a strong correlation with the ilio-femoral vessels with no correlation with the thoracic or neck vessels. On multiple linear regression, no correlation between CIMT and global atheroma burden was present (β 0.13 p = 0.45), while the correlation between ABPI and atheroma burden persisted (β -0.45 p = 0.005).ABPI but not CIMT correlates with global atheroma burden as measured by whole body contrast enhanced magnetic resonance angiography in a population with symptomatic peripheral arterial disease. However this is primarily due to a strong correlation with ilio-femoral atheroma burden