Ground-Based Mobile Measurements to Track Urban Methane Emissions from Natural Gas in 12 Cities across Eight Countries

To mitigate methane emission from urban natural gas distribution systems, it is crucial to understand local leak rates and occurrence rates. To explore urban methane emissions in cities outside the U.S., where significant emissions were found previously, mobile measurements were performed in 12 cities across eight countries. The surveyed cities range from medium size, like Groningen, NL, to large size, like Toronto, CA, and London, UK. Furthermore, this survey spanned across European regions from Barcelona, ES, to Bucharest, RO. The joint analysis of all data allows us to focus on general emission behavior for cities with different infrastructure and environmental conditions. We find that all cities have a spectrum of small, medium, and large methane sources in their domain. The emission rates found follow a heavy-tailed distribution, and the top 10% of emitters account for 60-80% of total emissions, which implies that strategic repair planning could help reduce emissions quickly. Furthermore, we compare our findings with inventory estimates for urban natural gas-related methane emissions from this sector in Europe. While cities with larger reported emissions were found to generally also have larger observed emissions, we find clear discrepancies between observation-based and inventory-based emission estimates for our 12 cities.

Quantum circuits with many photons on a programmable nanophotonic chip

Growing interest in quantum computing for practical applications has led to a surge in the availability of programmable machines for executing quantum algorithms1,2. Present-day photonic quantum computers3-7 have been limited either to non-deterministic operation, low photon numbers and rates, or fixed random gate sequences. Here we introduce a full-stack hardware-software system for executing many-photon quantum circuit operations using integrated nanophotonics: a programmable chip, operating at room temperature and interfaced with a fully automated control system. The system enables remote users to execute quantum algorithms that require up to eight modes of strongly squeezed vacuum initialized as two-mode squeezed states in single temporal modes, a fully general and programmable four-mode interferometer, and photon number-resolving readout on all outputs. Detection of multi-photon events with photon numbers and rates exceeding any previous programmable quantum optical demonstration is made possible by strong squeezing and high sampling rates. We verify the non-classicality of the device output, and use the platform to carry out proof-of-principle demonstrations of three quantum algorithms: Gaussian boson sampling, molecular vibronic spectra and graph similarity8. These demonstrations validate the platform as a launchpad for scaling photonic technologies for quantum information processing.

Broadband quadrature-squeezed vacuum and nonclassical photon number correlations from a nanophotonic device

We report demonstrations of both quadrature-squeezed vacuum and photon number difference squeezing generated in an integrated nanophotonic device. Squeezed light is generated via strongly driven spontaneous four-wave mixing below threshold in silicon nitride microring resonators. The generated light is characterized with both homodyne detection and direct measurements of photon statistics using photon number-resolving transition-edge sensors. We measure 1.0(1) decibels of broadband quadrature squeezing (~4 decibels inferred on-chip) and 1.5(3) decibels of photon number difference squeezing (~7 decibels inferred on-chip). Nearly single temporal mode operation is achieved, with measured raw unheralded second-order correlations g ⁽²⁾ as high as 1.95(1). Multiphoton events of over 10 photons are directly detected with rates exceeding any previous quantum optical demonstration using integrated nanophotonics. These results will have an enabling impact on scaling continuous variable quantum technology.

Chromosome Damage Caused by Accidental Chronic Whole-Body Gamma Radiation Exposure in Thailand

In February 2000, a radiation incident involving a medical ⁶⁰Co source occurred in a metal scrapyard in Thailand. Several individuals were suspected to have received chronic or fractionated exposures ranging from a few mGy to a several Gy. Using fluorescence in situ hybridization to paint chromosomes, we determined the frequencies of chromosome aberrations in peripheral blood lymphocytes of 13 people who entered the scrapyard, 3 people who involved in recovering the source, and 9 nearby residents. Aberration frequencies greater than controls were observed in 13 of the donors at 3 months postexposure. The predominant form of aberration observed was simple, complete, symmetrical translocations. An approximate 50% decrease in these aberrations and in total color junctions was observed in 7 donors resampled at 16 months postexposure. Although high, acute exposures are known to have detrimental effects, the biological consequences of chronic, low dose-rate radiation exposures are unclear. Thirteen of the donors had elevated aberration frequencies, and 6 also had symptoms of acute radiation syndrome. If there are any long-term health consequences of this incident, it will most likely occur among this group of individuals. The consequences for the remaining donors, who presumably received lower total doses delivered at lower dose rates, are less clear.

Red blood cell antigen portrait of self-identified black donors in Quebec

OBJECTIVES

The goal of this study was to establish a red blood cell antigen portrait of self-identified Black donors for the province of Quebec, Canada.

BACKGROUND

The demand for extensively phenotyped red blood cells is on the rise. A good example is the sickle cell patient cohort. To better answer their transfusion needs, Héma-Québec put forward great efforts to increase the recruitment of donors among cultural communities.

MATERIALS AND METHODS

In October 2009, an optional question was added on the record of donation to indicate the donor's ethnicity. Self-identified Black donors were extensively phenotyped by the Immunohematology Laboratory, whereas the Research and Development team genotyped red blood cell antigens to complete the picture.

RESULTS

Approximately 1500 self-identified Black donors have donated blood at least once since the beginning of the programme. Genotyping results predicted rare phenotypes: 18 S-s- (3 U-, 15 U+(w) ), 15 Js(a+b-), 5 Hy-, 3 Jo(a-), 34 hr(B) +(w) /- and 15 hr(B)-.

CONCLUSION

These Black donors, with or without a rare phenotype, are precious to the patient cohort depending on blood transfusions and to our organisation as the blood provider for the whole province of Quebec.

Treatment of Lymphoid Malignancies with Non-myeloablative Stem Cell Transplantation

The traditional approach to allogeneic hematopoietic stem cell transplantation involves the administration of myeloablative preparative regimens. This form of conditioning is associated with a relatively high incidence of regimen-related toxicity. As a result, candidates for allogeneic stem cell transplantation may be excluded owing to advanced age or co-morbid medical illness. Recently, so-called "non-myeloablative" regimens have been introduced, where less intense conditioning therapy is used in an attempt to reduce regimen-related toxicity. In addition, non-myeloablative transplantation takes advantage of the graft-versus-tumour effect that is characteristic of allogeneic stem cell transplantation. We review the background, available clinical data, and future directions in non-myeloablative stem cell transplantation, and focus on its potential use in the treatment of lymphoid malignancies.

Canadian College of Medical Geneticists guidelines for the indications, analysis, and reporting of cancer specimens

The Canadian College of Medical Geneticists (ccmg) is a national organization of medical and laboratory geneticists. The mission of the ccmg is to establish and maintain high-quality professional and ethical standards for medical genetics services in Canada and to help to ensure that service of the highest quality is delivered to the Canadian public.Cancer cytogenetics is one of the sections of practice of the ccmg. The ccmg Cytogenetic Committee has, therefore, put forward guidelines to provide oncologists and ccmg cytogeneticists with a comprehensive review of the cytogenetic diagnostic tests that are recommended as a minimum standard of care for tumours of hematopoietic and lymphoid tissues and for tumours of soft tissue and bone. The guidelines were approved by the ccmg board of directors in June 2010.

Using cheminformatics to find simulants for chemical warfare agents

Direct experimentation with chemical warfare agents (CWA) to study important problems such as their permeation across protective barrier materials, decontamination of equipment and facilities, or the environmental transport and fate of CWAs is not feasible because of the obvious toxicity of the CWAs and associated restrictions on their laboratory use. The common practice is to use "simulants," namely, analogous chemicals that closely resemble the CWAs but are less toxic, with the expectation that the results attained for simulants can be correlated to how the CWAs would perform. Simulants have been traditionally chosen by experts, by means of intuition, using similarity in one or more physical properties (such as vapor pressure or aqueous solubility) or in the molecular structural features (such as functional groups) between the stimulant and the CWA. This work is designed to automate the simulant identification process backed by quantitative metrics, by means of chemical similarity search software routinely used in pharmaceutical drug discovery. The question addressed here is: By the metrics of such software, how similar are traditional simulants to CWAs? That is, what is the numerical "distance" between each CWA and its customary simulants in the quantitative space of molecular descriptors? The answers show promise for finding close but less toxic simulants for the ever-increasing numbers of CWAs objectively and fast.

CCMG guidelines: prenatal and postnatal diagnostic testing for uniparental disomy

The aim of this statement is to provide clinicians, cytogeneticists and molecular geneticists of the Canadian College of Medical Geneticists (CCMG) a comprehensive review of the role of UPD in constitutional genetic diagnosis and to provide a guideline as to when investigation for UPD is recommended. Members of the CCMG Cytogenetics, Molecular Genetics, Clinical Practice, and Prenatal Diagnosis committees reviewed the relevant literature on uniparental disomy (UPD) in constitutional genetic diagnosis (May 2010). Guidelines were developed for UPD testing in Canada. The guidelines were circulated for comment to the CCMG members at large and following appropriate modification, approved by the CCMG Board of Directors (July 2010).

Anesthetic technique and postoperative outcome in preterm infants undergoing PDA closure

OBJECTIVE

To describe the various anesthetic techniques used for surgical closure of PDA in premature infants at the Montreal Children's Hospital and assess their impact on postoperative outcome.

STUDY DESIGN

The charts of all preterms who underwent PDA ligation during a 21-month period were reviewed for preoperative status, intraoperative anesthetic management and postoperative outcome. We determined the associations between independent variables and two postoperative outcome variables: unstable postoperative respiratory course (UPRC) and hypotension.

RESULT

The mean weight at surgery of the 33 infants was 1.031±0.29 kg. All infants, but one, received intraoperative opioids. Eight patients presented UPRC. Mean fentanyl doses were 5.3±2.6 mcg kg(-1) for patients with UPRC vs 22.6±16.6 mcg kg(-1) for patients without UPRC (P=0.004). Applying the receiver-operator characteristic curve (ROC), 10.5 mcg kg(-1) of fentanyl was established as the dose that discriminated and identified patients who experienced UPRC. The postnatal and postmenstrual age of the patient, birthweight, current weight, ventilator settings preoperatively, previous courses of indomethacin, sex and preoperative creatinine, were not correlated with the dose of fentanyl equivalent used. Logistic regression did not show a relationship between any of the previously mentioned factors and receiving a fentanyl equivalent of >10.5 mcg kg(-1). The only factor associated with the total fentanyl equivalent dose (as a continuous variable) or receiving <10.5 mcg kg(-1) (as a dichotomous variable) was the identity of the anesthetist involved, P<0.001.

CONCLUSION

We conclude that the use of at least 10.5 mcg kg(-1) of fentanyl equivalent as a component of the anesthetic regimen for surgical closure of a PDA in premature infants, avoids an unstable postoperative respiratory course.

Impact of in-barn manure separation on biological air quality in an experimental setup identical to that in swine buildings

In-barn manure separation systems are becoming popular due to various environmental pressures on the swine industry. According to the literature, separation of feces and urine directly underneath the slats should have a positive impact on barn air quality. Removal and rapid separation of the two phases (solid/liquid) would reduce the dust and bioaerosol emissions, which would significantly improve the air quality in pig-housing facilities. From an occupational health and safety perspective, the maximum endotoxin and total bacteria concentrations to ensure workers' safety should not exceed 450 endotoxin units per cubic meter of air (EU m(-3)) and 10(4) colony-forming units per cubic meter of air (CFU m(-3)), respectively. In the current study, the effect on air quality of six in-barn manure handling systems was measured. A flat scraper system and four separation systems installed under the slats (a conveyor belt system, a conveyor net system, and a V-shaped scraper operated at two operation frequencies) were evaluated and compared to a conventional pull-plug system (control). The experiment took place in twelve independent and identical rooms housing four grower-finisher pigs each, and air samples were collected and analyzed for total dust, endotoxins, bacteria, and mold counts. The results obtained from this experimental setup show that the separation of feces and urine under the slats would concentrate at least 80% of the phosphorus in the solid phase. The total bacteria and endotoxin concentrations are lower than those found in commercial hog barns but remain higher than the recommended levels. Only the total dust concentrations are approximately 10% of their regulated value. This separation has no impact on dust and bioaerosol concentrations compared to the control.