Generation of high speed polarization modulated data using a monolithically integrated device

We report on the generation of high speed polarization modulated data via direct electrical binary data injection to the phase shifter section of a monolithically integrated laser diode integrated with a polarization controller. The device is fabricated on standard InP/AlGaInAs multiple quantum-well material and consists of a semiconductor laser, a passive polarization mode convertor and an active differential phase-shifter section. We demonstrate the generation of 300 Mbit/s Polarization Shift Keyed data

High visibility two photon interference of frequency time entangled photons generated in a quasi phase matched AlGaAs waveguide

We demonstrate experimentally the frequency time entanglement of photon pairs produced in a CW pumped quasi phased matched AlGaAs superlattice waveguide. A visibility of 96.0+-0.7% without background subtraction has been achieved, which corresponds the violation of Bell inequality by 52 standard deviations

Rumen function and digestion parameters associated with differences between sheep in methane emissions when fed chaffed lucerne hay

An indoor experiment involving 10 rumen-cannulated Romney sheep was conducted in May and June 1998 at AgResearch Grasslands, Palmerston North, New Zealand, under restricted feeding conditions. in order to test the hypothesis that animal factors, in particular rumen fractional outflow rate (FOR) and rumen volume, have an influence on the between-sheep variation in methane (CH4) emission. Sheep were fed 2-hourly on chaffed lucerne hay. Following an acclimatization period of 21 days, the experiment lasted 16 days. Energy and nitrogen (N) balances were measured on days 1-6. Cr-EDTA marker was continuously infused into the rumen from day 9 to 16, and rumen contents emptied and sampled on days 13 and 16. Particulate and fluid FOR were estimated using feed lignin and Cr-EDTA, respectively. Daily CH, production was measured by the sulphur hexafluoride tracer technique on days 2, 5, 6, 12 and 15 of the experiment. CH4 production (g/day) was positively correlated with the pool size of organic matter (OM) in the rumen (OM pool, g) (r = 0.84, P = 0.002), OM intake (OMI, g/day) (r = 0.67, P = 0.04), and the rumen fill (g. wet digesta) (r = 0.76, P = 0.01). Multiple regression analysis showed that CH4 production was best predicted (R-2 = 0.88) as a function of OM pool and the molar % of butyrate; however, OM pool alone accounted for a large proportion (R-2 = 0.71) of the variation in CH4 production. CH4 yield (% gross energy intake, % GEI) was negatively correlated with the particulate FOR (%/h) ( r= -0.75, P = 0.01) and buffering capacity of rumen fluid (mmol HCl) (r = -0.72, P = 0.02) but positively correlated with the digestibility of cellulose (r = 0.66, P = 0.04). Multiple regression analysis showed that CH, yield was best predicted as a function of particulate FOR, OMI (g/kg liveweight(0.75)) and the molar % of butyrate (R-2 = 0.88). Particulate FOR alone explained a large proportion (R-2 = 0.57) of the variation in CH4 Yield. Particulate FOR was negatively correlated with rumen fill (r = -0.69, P = 0.03) and digestibility of cellulose (r = -0.65, P = 0.04). These results suggest that sheep with lower rumen particulate FOR (i.e. longer rumen retention times) had larger rumen fills and higher fibre digestibilities and CH4 yields. If rumen particulate FOR is to be used as a tool for CH4 mitigation, the repeatability of its relationship to CH4 emission must be assessed, preferably under grazing conditions

Persistence of differences between sheep in methane emission under generous grazing conditions

Four low and four high methane (CH4) emitters were selected from a flock of 20 Romney sheep on the basis of CH4 production rates per unit of intake, measured at grazing using the sulphur hexafluoride (SF,) tracer technique. Methane emissions from these sheep were monitored at grazing for four periods (P): October, November, January and February 1999/2000. All measurements were carried out on perennial ryegrass/white clover pasture under generous herbage allowance, and the sheep were maintained on similar pastures during non-measurement periods. The tracer technique was used for all the CH4 measurements and feed DM intake was calculated from total faecal collection and estimated DM digestibility. Data for liveweight (LW), gross energy intake (GEI) and CH4 emission were analysed using split-plot analysis of variance. In addition, a between-period rank order correlation analysis was carried out for CH4 emission data. Low CH4 emitters were heavier (P < 0.05) than the high emitters in all the periods, but they did not differ (P < 0.05) in their gross energy intakes (GEL MJ/kg LW0.75). Low and high CH4 emitters consistently maintained their initial rankings in CH4 yield (% GEI) throughout the subsequent periods and the correlation analysis of rank order for CH4 yield showed strong between-period correlation coefficients, although this was weaker in the last period. It is suggested that feeding conditions that maximize feed intake (e.g. generous allowance of good quality pasture under grazing) favour the expression and persistence of between-sheep differences in CH4 yield

International Students Reported for Academic Integrity Violations: Demographics, Retention, and Graduation

How many international students are reported for academic integrity violations (AIV), what are their demographics, and how do AIV sanctions affect their retention and/or graduation? Descriptive statistical analyses showed that the number of internationals reported for AIVs at an American West Coast public university increased almost six-fold between academic years 2009–10 and 2013–14. However, that number represented less than 7.5% of these students’ total enrollment. Among reported ones, undergraduates outnumbered graduate students, males outnumbered females, Chinese outnumbered other nationalities, Economics majors outnumbered other majors, and the most common AIV was exam misconduct. More than half who were reported and suspended for AIVs graduated and/or were retained. These findings’ administrative, policy, and theoretical implications are discussed

International Undergraduates’ Retention, Graduation, and Time to Degree

The present study tested the hypothesis that the international undergraduates at a West Coast American public university during recent years of dramatic enrollment growth should have low retention and graduation rates. This study showed instead that these students were retained and graduated at rates surpassing predictions from research and theories on international undergraduates’ unique challenges (American immigration regulations, academic integrity standards, and teaching methods; English writing) and academic struggles. Moreover, contrary to predictions related to academic struggles, the primary reasons for these students’ attrition were leave of absence for compulsory military service and deciding against attending the University. These results disconfirm the study’s hypothesis and instead suggest that these international undergraduates generally have succeeded academically

Methane emission by alpaca and sheep fed on lucerne hay or grazed on pastures of perennial ryegrass/white clover or birdsfoot trefoil

Based on the knowledge that alpaca (Lama pacos) have a lower fractional outflow rate of feed particles (particulate FOR) from their forestomach than sheep (San Martin 1987), the current study measured methane (CH4) production and other digestion parameters in these species in three successive experiments (1, 2 and 3): Experiment 1, lucerne hay fed indoors; Experiment 2, grazed on perennial ryegrass/white clover pasture (PRG/WC); and Experiment 3, grazed on birdsfoot trefoil (Lotus corniculatits) pasture (Lotus). Six male alpaca and six castrated Romney sheep were simultaneously and successively fed on the forages either ad libitium or at generous herbage allowances (grazing). CH4 production (g/day) (using the sulphur hexafluoride tracer technique), voluntary feed intake (VFI), diet quality, and protozoa counts and volatile fatty acid concentrations in samples of forestomach contents were determined. In addition, feed digestibility, energy and nitrogen (N) balances and microbial N supply from the forestomach (using purine derivatives excretion) were measured in Experiment 1. Diets selected by alpaca were of lower quality than those selected by sheep, and the voluntary gross energy intakes (GEI, MJ) per kg of liveweight(0.75) were consistently lower (P0.05) in their CH4 yields (% GEI) when fed on lucerne hay (5.1 v. 4.7), but alpaca had a higher CH4 yield when fed on PRG/WC (9.4 v. 7.5, P0.05) in diet N partition or microbial N yield, but alpaca had higher (P<0.05) neutral detergent fibre digestibility (0.478 v. 0.461) and lower (P<0.01) urinary energy losses (5.2 v. 5.8 % GEI) than sheep. It is suggested that differences between these species in forestomach particulate FOR might have been the underlying physiological mechanism responsible for the differences in CH4 yield, although the between-species differences in VFI and diet quality also had a major effect on it

Effects of Accelerated Carbonation Curing on CO2 Sequestration and on the Compressive Strength of Concrete Masonry Units

The global consumption of Portland cement has risen to over 4 billion tonnes per annum. Its manufacture is energy and carbon intensive and approximately 900 kg of CO2 is emitted into the atmosphere for each tonne of Portland cement produced. The International Energy Agency (IEA) roadmap sets out a goal to reduce emissions due to cement production to 18 % below 2006 levels by 2050. Concrete has the potential to re-absorb CO2 by the process of carbonation, where it reacts with CaO in the concrete to form calcium carbonate. Accelerated carbonation curing (ACC) is a technique for curing fresh concrete that can sequester CO2. ACC of concrete masonry units (CMU’s) can reduce the embodied carbon footprint and play a major role in sustainability by reducing global CO2. ACC also offers potential improvements in the mechanical and durability properties of concrete. Experimental work was carried out which involved the ACC of CMU’s at a CO2 concentration of 50% over various time intervals and exposure conditions. It was calculated that the maximum possible CO2 uptake potential of the cement was approximately 49.5%. A CO2 uptake of 23% per mass of cement was achieved after 7 days of ACC along with compressive strength increases of 15.4% and 28% for ACC samples at 7 and 28 days respectively. The study found that the greatest compressive strength increase occurred between 4 and 24 hours. After 24 hours the ACC process showed a similar proportional rate of strength gain over time when compared to the control. The study shows that ACC is different from weathering carbonation as it accelerates the hydration reaction of the unhydrated cement phases C3S and C2S producing rapid strength gains. Weathering carbonation occurs in concrete after the hydration process has been predominately completed and results in the decalcification of C-S-H and the formation of silica gel which is detrimental to the cement paste

Transcriptional profiling of Medicago truncatula meristematic root cells

BACKGROUND: The root apical meristem of crop and model legume Medicago truncatula is a significantly different stem cell system to that of the widely studied model plant species Arabidopsis thaliana. In this study we used the Affymetrix Medicago GeneChip® to compare the transcriptomes of meristem and non-meristematic root to identify root meristem specific candidate genes. RESULTS: Using mRNA from root meristem and non-meristem we were able to identify 324 and 363 transcripts differentially expressed from the two regions. With bioinformatics tools developed to functionally annotate the Medicago genome array we could identify significant changes in metabolism, signalling and the differentially expression of 55 transcription factors in meristematic and non-meristematic roots. CONCLUSION: This is the first comprehensive analysis of M. truncatula root meristem cells using this genome array. This data will facilitate the mapping of regulatory and metabolic networks involved in the open root meristem of M. truncatula and provides candidates for functional analysis.This research is supported by a grant from the Australian Research Council Centre of Excellence Program (CE0348212). PH was supported by an Australian Postgraduate Award. We thank Lily Shen from the ANU Electron Microscopy Unit for assistance with microscopy