Applied constant gain amplification in circulating loop experiments

The reconfiguration of channel or wavelength routes in optically transparent mesh networks can lead to deviations in channel power that may impact transmission performance. A new experimental approach, applied constant gain, is used to maintain constant gain in a circulating loop enabling the study of gain error effects on long-haul transmission under reconfigured channel loading. Using this technique we examine a number of channel configurations and system tuning operations for both full-span dispersion-compensated and optimized dispersion-managed systems. For each system design, large power divergence was observed with a maximum of 15 dB at 2240 km, when switching was implemented without additional system tuning. For a bit error rate of 10-3, the maximum number of loop circulations was reduced by up to 33%

Dynamic circulating-loop methods for transmission experiments in optically transparent networks

Recent experiments incorporating multiple fast switching elements and automated system configuration in a circulating loop apparatus have enabled the study of aspects of long-haul WDM transmission unique to optically transparent networks. Techniques include per-span switching to measure the performance limits due to dispersion compensation granularity and mesh network walk-off, and applied constant-gain amplification to evaluate wavelength reconfiguration penalties

10Gbit/s modulation of a fast switching slotted Fabry-Pérot tunable laser

The device used is a three-section, 3mum wide ridge waveguide laser based on commercially available material. During the fabrication a series of slots are introduced into the front and back sections, which act as sites of internal reflections. The slots are etched to a depth that just penetrates the top of the upper waveguide resulting in an internal reflectance of-1% at each slot. The front, middle, and back sections are 180, 690 and 170 microns long respectively. In this work the back and middle sections are tied together electrically allowing simpler control of the device. By varying the applied DC currents, eight discrete channels are observed over a range of approximately 19nm

Linguistic input is tuned to children’s developmental level

Children rapidly learn a tremendous amount about languagedespite limitations imposed on them by their developing cog-nitive abilities. One possible explanation for this rapid learn-ing is that caregivers tune the language they produce tothese limitations, titrating the complexity of their speech todevelopmentally-appropriate levels. We test this hypothesis ina large-scale corpus analysis, measuring the contingency be-tween parents’ and children’s speech over the first 5 years.Our results support the linguistic tuning hypothesis, showinga high degree of mostly parent-led coordination early in de-velopment that decreases as children become more proficientlanguage learners and users

Age-related changes to macrophages are detrimental to fracture healing in mice.

The elderly population suffers from higher rates of complications during fracture healing that result in increased morbidity and mortality. Inflammatory dysregulation is associated with increased age and is a contributing factor to the myriad of age-related diseases. Therefore, we investigated age-related changes to an important cellular regulator of inflammation, the macrophage, and the impact on fracture healing outcomes. We demonstrated that old mice (24 months) have delayed fracture healing with significantly less bone and more cartilage compared to young mice (3 months). The quantity of infiltrating macrophages into the fracture callus was similar in old and young mice. However, RNA-seq analysis demonstrated distinct differences in the transcriptomes of macrophages derived from the fracture callus of old and young mice, with an up-regulation of M1/pro-inflammatory genes in macrophages from old mice as well as dysregulation of other immune-related genes. Preventing infiltration of the fracture site by macrophages in old mice improved healing outcomes, with significantly more bone in the calluses of treated mice compared to age-matched controls. After preventing infiltration by macrophages, the macrophages remaining within the fracture callus were collected and examined via RNA-seq analysis, and their transcriptome resembled macrophages from young calluses. Taken together, infiltrating macrophages from old mice demonstrate detrimental age-related changes, and depleting infiltrating macrophages can improve fracture healing in old mice

Kinetics and crystallization path of a Fe-based metallic glass alloy

The thermal stability and the quantification of the different transformation processes involved in the overall crystallization of the Fe50Cr15Mo14C15B6 amorphous alloy were investigated by several characterization techniques. Formation of various metastable and stable phases during the devitrification process in the sequence a-Fe, ¿-Cr6Fe18Mo5, M23(C,B)6, M7C3, ¿-Fe3Mo3C and FeMo2B2 (with M = Fe, Cr, Mo), was observed by in-situ synchrotron high energy X-ray diffraction and in-situ transmission electron microscopy. By combining these techniques with differential scanning calorimetry data, the crystallization states and their temperature range of stability under continuous heating were related with the evolution of the crystallized fraction and the phase sequence as a function of temperature, revealing structural and chemical details of the different transformation mechanisms.Postprint (published version

Anatomy, Biology and Concepts, Pertaining to Lung Cancer Stage Classification

AbstractThe proposed lung cancer stage classification system remains grounded in anatomic characteristics, although the large patient database contributing to this revision has dramatically expanded our body of knowledge. Predictably this has led to increased complexity due to the identification of an increasing number of subpopulations of patients. Patterns of clinical presentation characterizing these subgroups may provide clues about the propensity of tumors within a subgroup toward a particular pattern of biologic behavior. This article explores concepts regarding tumor biology that can be applied to the anatomically based new staging system

South Asian monsoon history over the past 60 kyr recorded by radiogenic isotopes and clay mineral assemblages in the Andaman Sea

The Late Quaternary variability of the South Asian (or Indian) monsoon has been linked with glacial‐interglacial and millennial scale climatic changes but past rainfall intensity in the river catchments draining into the Andaman Sea remains poorly constrained. Here we use radiogenic Sr, Nd, and Pb isotope compositions of the detrital clay‐size fraction and clay mineral assemblages obtained from sediment core NGHP Site 17 in the Andaman Sea to reconstruct the variability of the South Asian monsoon during the past 60 kyr. Over this time interval εNd values changed little, generally oscillating between −7.3 and −5.3 and the Pb isotope signatures are essentially invariable, which is in contrast to a record located further northeast in the Andaman Sea. This indicates that the source of the detrital clays did not change significantly during the last glacial and deglaciation suggesting the monsoon was spatially stable. The most likely source region is the Irrawaddy river catchment including the Indo‐Burman Ranges with a possible minor contribution from the Andaman Islands. High smectite/(illite + chlorite) ratios (up to 14), as well as low 87Sr/86Sr ratios (0.711) for the Holocene period indicate enhanced chemical weathering and a stronger South Asian monsoon compared to marine oxygen isotope stages 2 and 3. Short, smectite‐poor intervals exhibit markedly radiogenic Sr isotope compositions and document weakening of the South Asian monsoon, which may have been linked to short‐term northern Atlantic climate variability on millennial time scales