Common Types Of Sources Research Articles

Rare metal concentration features at a caldera type deposit in the Miocene-Quaternary boron-lithium province of North America. Search for analogues

The fact that lithium has a wide range of applications in many fields including the production of lithium-ion batteries determines an increased interest in lithium mining. The most common types of lithium raw material sources are underground brines, saline lakes (“salars”), and ore minerals. In 2021, the first and unique deposit of lithium clays was discovered in the McDermitt caldera (Nevada, USA). Its resources are estimated at 13.7 million tons of lithium carbonate with the lithium concentration of 2231 mg/l. The uniqueness of this deposit raises the interest in the formation of model ideas about lithiumclay genesis to search for analogous deposits and explore them. The purpose of the article is to provide an overview of the geological structure and describe the main development periods of the McDermitt caldera. The authors also characterize the potential sources of lithium (felsic igneous rocks and hydrothermal fluids), migration paths of lithium-bearing brines as well as the formation mechanism of clays with a high lithium content (hectorite, illite and smectite). A generalized formation model of this type of deposits is proposed. Particular attention is paid to the role of hydrothermal fluids as a potential additional source of lithium “supply” to the caldera basin. Key criteria characteristic of industrial accumulations of lithium of this type have been formed in order to explore and identify analogous deposits. In conclusion, the authors put forward a hypothesis about the presence of deposits that are analogous to the Thacker Pass in the McDermitt caldera in the lithium province on the Altiplano-Puna plateau in one of the calderas of the Altiplano-Puna volcanic complex, and in Eastern Kamchatka.

A global view on star formation: The GLOSTAR Galactic plane survey

As part of the GLObal view of STAR formation in the Milky Way (GLOSTAR) survey, we present the high-resolution continuum source catalog for the regions (ℓ = 2° −28°, 36° −40°, 56° −60°, and |b| < 1.0°), observed with the Karl G. Jansky Very Large Array (VLA) in its B-configuration. The continuum images were optimized to detect compact sources on angular scales up to 4″, and have a typical noise level of 1σ ~ 0.08 mJy beam−1 for an angular resolution of 1″, which makes GLOSTAR currently the highest resolution as well as the most sensitive radio survey of the northern Galactic plane at 4–8 GHz. We extracted 13354 sources above a threshold of 5σ and 5437 sources above 7σ that represent the high-reliability catalog. We determined the in-band spectral index (α) for the sources in the 7σ-threshold catalog. The mean value is α = −0.6, which indicates that the catalog is dominated by sources emitting nonthermal radio emission. We identified the most common source types detected in radio surveys: 251 H II region candidates (113 new), 282 planetary nebulae (PNe) candidates (127 new), 784 radio star candidates (581 new), and 4080 extragalactic radio source candidates (2175 new). A significant fraction of H II regions and PNe candidates have α < −0.1 indicating that these candidates could contain radio jets, winds or outflows from high-mass and low-mass stellar objects. We identified 245 variable radio sources by comparing the flux densities of compact sources from the GLOSTAR survey and the Co-Ordinated Radio “N” Infrared Survey for High-mass star formation (CORNISH), and find that most of them are infrared quiet. The catalog is typically 95% complete for point sources at a flux density of 0.6 mJy (i.e., a typical 7σ level) and the systematic positional uncertainty is ≲ 0″.1.

Positioning Using Visible Light Communications: A Perspective Arcs Approach

Visible light positioning (VLP) is an accurate indoor positioning technology that uses luminaires as transmitters. In particular, circular luminaires are a common source type for VLP, which are typically treated only as point sources for positioning, while ignoring their geometry characteristics. In this paper, the arc feature of the circular luminaire and the coordinate information obtained via visible light communication (VLC) are jointly used for positioning, and a novel perspective arcs approach is proposed for VLC-enabled indoor positioning. The proposed approach does not rely on any inertial measurement unit and has no tilted angle limitation at the user. First, a VLC assisted perspective circle and arc algorithm (V-PCA) is proposed for a scenario in which a complete luminaire and an incomplete one can be captured by the user. Based on plane and solid geometry theory, the relationship between the luminaire and the user is exploited to estimate the orientation and the coordinate of the luminaire in the camera coordinate system. Then, the pose and location of the user in the world coordinate system are obtained by single-view geometry theory. Considering the cases in which parts of VLC links are blocked, an anti-occlusion VLC assisted perspective arcs algorithm (OA-V-PA) is proposed. In OA-V-PA, an approximation method is developed to estimate the projection of the luminaire’s center on the image and, then, to calculate the pose and location of the user. Simulation results show that the proposed indoor positioning algorithm can achieve a 90th percentile positioning accuracy of around 10 cm. Moreover, an experimental prototype is implemented to verify the feasibility. In the established prototype, a fused image processing method is proposed to simultaneously obtain the VLC information and the geometric information. Experimental results in the established prototype show that the average positioning accuracy is less than 5 cm for different tilted angles of the user.

Insights Into Patients Questions Over Bunion Treatments: A Google Study.

Approximately 1 in 4 adults will develop hallux valgus (HV). Up to 80% of adult Internet users reference online sources for health-related information. Overall, with the high prevalence of HV combined with the numerous treatment options, we believe patients are likely turning to Internet search engines for questions relevant to HV. Using Google's people also ask (PAA) or frequently asked questions (FAQs) feature, we sought to classify these questions, categorize the sources, as well as assess their levels of quality and transparency. On October 9, 2022, we searched Google using these 4 phrases: "hallux valgus treatment," "hallux valgus surgery," "bunion treatment," and "bunion surgery." The FAQs were classified in accordance with the Rothwell Classification schema and each source was categorized. Lastly, transparency and quality of the sources' information were evaluated with the Journal of the American Medical Association's (JAMA) Benchmark tool and Brief DISCERN, respectively. Once duplicates and FAQs unrelated to HV were removed, our search returned 299 unique FAQs. The most common question in our sample was related to the evaluation of treatment options (79/299, 26.4%). The most common source type was medical practices (158/299, 52.8%). Nearly two-thirds of the answer sources (184/299; 61.5%) were lacking in transparency. One-way analysis of variance revealed a significant difference in mean Brief DISCERN scores among the 5 source types, F(4) = 54.49 (P < .001), with medical practices averaging the worst score (12.1/30). Patients seeking online information concerning treatment options for HV search for questions pertaining to the evaluation of treatment options. The source type encountered most by patients is medical practices; these were found to have both poor transparency and poor quality. Publishing basic information such as the date of publication, authors or reviewers, and references would greatly improve the transparency and quality of online information regarding HV treatment. Level V, mechanism-based reasoning.

Development of “Green” Energy in Russia

The article presents the main factors influencing the country’s transition to a “green” energy, as opposed to the energy, the development of which is accompanied by large-scale environmental pollution, as well as the accumulation of a significant amount of production and consumption waste. The results of comparative calculations of the main parameters for traditional and non-traditional power plants for the conditions of Russia are considered. The comparison was made for nuclear power plants, thermal power plants operating on coal and on natural gas; hydroelectric power station; as well as network wind farms and solar power plants – without accumulation. It is shown that a promising direction in the construction of wind and solar power plants, as well as other generating facilities based on RES, is to cover the own energy needs of various enterprises and organizations. The proposed direction of energy development is promising and economically beneficial also due to the fact that biomass in our country is one of the most common types of renewable energy sources. About 48% of the world’s peat reserves and 23–24% of timber are concentrated in Russia, as well as huge amounts of agricultural waste. The article proposes effective technical solutions in the field of energy use of biomass. It is shown that for Russia a promising direction for the modernization of the existing energy supply system is the combined use of various types of renewable energy sources and local bioenergy resources that complement each other and provide guaranteed energy supply to consumers while minimizing the required investments.

Water in the city: visitation of animal wildlife to garden water sources and urban lakes

Providing garden water sources (e.g., ponds, bird baths) has become a popular and strongly promoted form of wildlife-friendly gardening, yet evidence of their use by animals is scarce and limited to a few taxa and water source types. We examined the prevalence, variety and potential value to animal wildlife of supplementary water provided within gardens of Hertfordshire, United Kingdom, using an online questionnaire and field observations of wildlife visitation to urban water sources during summer 2021. Over 70% of 105 questionnaire respondents indicated the presence of at least one water source in their garden and almost 50% had two or more. Bird baths, ground water-bowls and ponds were the most common water source types provided. During 207 h of field observation, we recorded a total of 43 taxa (birds, insects, mammals, amphibians, reptiles) visiting urban lakes and garden birth baths, ponds and ground water-bowls. Taxa richness was similar at urban lakes (30) and garden water sources (27), although approximately 50% of the taxa recorded in each location were unique to that location. Visitation rates of smaller-bodied wildlife did not differ between lakes and gardens, nor among individual water source types. Multivariate analyses indicated insect assemblages visiting lakes did not differ from those visiting garden water sources, and small bird assemblages did not differ among each water source type. These results demonstrate garden water sources, especially for smaller-bodied animals, can supplement the wildlife values contributed by urban lake systems, and should continue to be promoted as an effective conservation action.

Examining the Public's Most Frequently Asked Questions About Carpal Tunnel Syndrome and Appraising Online Information About Treatment.

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy. Patients often search online for health information regarding common musculoskeletal complaints. Thus, the purpose of this study was to use language processing information from Google to assess the content of CTS frequently asked questions (FAQs) searched online and the transparency and quality of online CTS information. On March 11, 2021, we searched Google for 3 terms "carpal tunnel syndrome treatment," "carpal tunnel syndrome surgical treatment," and "carpal tunnel syndrome non-surgical treatment" until a minimum of 100 FAQs and their answer links were extracted from each search. We used Rothwell classification to categorize the FAQs. The Journal of the American Medical Association's benchmark criteria were used to assess information transparency. Information quality was assessed using the Brief DISCERN tool. Our Google search returned 124 unique FAQs. Fifty-six (45.2%) were value based and most were related to the evaluation of treatment options (45/56, 80.4%). The most common source type was medical practices (26.6%). Nearly half of the answer sources (45.9%) were found to be lacking in transparency. One-way analysis of variance revealed a significant difference in mean Brief DISCERN scores among the 5 source types, F(4, 119) = 5.93, P = .0002, with medical practices averaging the worst score (13.73/30). Patients are most commonly searching Google to gain information regarding CTS treatment options. Online sources such as medical practices should use widely accepted rubrics for ensuring transparency and quality prior to publishing CTS information.

Promoting Social Distancing and COVID-19 Vaccine Intentions to Mothers: Randomized Comparison of Information Sources in Social Media Messages.

BackgroundSocial media disseminated information and spread misinformation during the COVID-19 pandemic that affected prevention measures, including social distancing and vaccine acceptance.ObjectiveIn this study, we aimed to test the effect of a series of social media posts promoting COVID-19 nonpharmaceutical interventions (NPIs) and vaccine intentions and compare effects among 3 common types of information sources: government agency, near-peer parents, and news media.MethodsA sample of mothers of teen daughters (N=303) recruited from a prior trial were enrolled in a 3 (information source) × 4 (assessment period) randomized factorial trial from January to March 2021 to evaluate the effects of information sources in a social media campaign addressing NPIs (ie, social distancing), COVID-19 vaccinations, media literacy, and mother–daughter communication about COVID-19. Mothers received 1 social media post per day in 3 randomly assigned Facebook private groups, Monday-Friday, covering all 4 topics each week, plus 1 additional post on a positive nonpandemic topic to promote engagement. Posts in the 3 groups had the same messages but differed by links to information from government agencies, near-peer parents, or news media in the post. Mothers reported on social distancing behavior and COVID-19 vaccine intentions for self and daughter, theoretic mediators, and covariates in baseline and 3-, 6-, and 9-week postrandomization assessments. Views, reactions, and comments related to each post were counted to measure engagement with the messages.ResultsNearly all mothers (n=298, 98.3%) remained in the Facebook private groups throughout the 9-week trial period, and follow-up rates were high (n=276, 91.1%, completed the 3-week posttest; n=273, 90.1%, completed the 6-week posttest; n=275, 90.8%, completed the 9-week posttest; and n=244, 80.5%, completed all assessments). In intent-to-treat analyses, social distancing behavior by mothers (b=–0.10, 95% CI –0.12 to –0.08, P<.001) and daughters (b=–0.10, 95% CI –0.18 to –0.03, P<.001) decreased over time but vaccine intentions increased (mothers: b=0.34, 95% CI 0.19-0.49, P<.001; daughters: b=0.17, 95% CI 0.04-0.29, P=.01). Decrease in social distancing by daughters was greater in the near-peer source group (b=–0.04, 95% CI –0.07 to 0.00, P=.03) and lesser in the government agency group (b=0.05, 95% CI 0.02-0.09, P=.003). The higher perceived credibility of the assigned information source increased social distancing (mothers: b=0.29, 95% CI 0.09-0.49, P<.01; daughters: b=0.31, 95% CI 0.11-0.51, P<.01) and vaccine intentions (mothers: b=4.18, 95% CI 1.83-6.53, P<.001; daughters: b=3.36, 95% CI 1.67-5.04, P<.001). Mothers’ intentions to vaccinate self may have increased when they considered the near-peer source to be not credible (b=–0.50, 95% CI –0.99 to –0.01, P=.05).ConclusionsDecreasing case counts, relaxation of government restrictions, and vaccine distribution during the study may explain the decreased social distancing and increased vaccine intentions. When promoting COVID-19 prevention, campaign planners may be more effective when selecting information sources that audiences consider credible, as no source was more credible in general.Trial RegistrationClinicalTrials.gov NCT02835807; https://clinicaltrials.gov/ct2/show/NCT02835807

Examining the Public's Most Frequently Asked Questions Regarding COVID-19 Vaccines Using Search Engine Analytics in the United States: Observational Study.

BackgroundThe emergency authorization of COVID-19 vaccines has offered the first means of long-term protection against COVID-19–related illness since the pandemic began. It is important for health care professionals to understand commonly held COVID-19 vaccine concerns and to be equipped with quality information that can be used to assist in medical decision-making.ObjectiveUsing Google’s RankBrain machine learning algorithm, we sought to characterize the content of the most frequently asked questions (FAQs) about COVID-19 vaccines evidenced by internet searches. Secondarily, we sought to examine the information transparency and quality of sources used by Google to answer FAQs on COVID-19 vaccines.MethodsWe searched COVID-19 vaccine terms on Google and used the “People also ask” box to obtain FAQs generated by Google’s machine learning algorithms. FAQs are assigned an “answer” source by Google. We extracted FAQs and answer sources related to COVID-19 vaccines. We used the Rothwell Classification of Questions to categorize questions on the basis of content. We classified answer sources as either academic, commercial, government, media outlet, or medical practice. We used the Journal of the American Medical Association’s (JAMA’s) benchmark criteria to assess information transparency and Brief DISCERN to assess information quality for answer sources. FAQ and answer source type frequencies were calculated. Chi-square tests were used to determine associations between information transparency by source type. One-way analysis of variance was used to assess differences in mean Brief DISCERN scores by source type.ResultsOur search yielded 28 unique FAQs about COVID-19 vaccines. Most COVID-19 vaccine–related FAQs were seeking factual information (22/28, 78.6%), specifically about safety and efficacy (9/22, 40.9%). The most common source type was media outlets (12/28, 42.9%), followed by government sources (11/28, 39.3%). Nineteen sources met 3 or more JAMA benchmark criteria with government sources as the majority (10/19, 52.6%). JAMA benchmark criteria performance did not significantly differ among source types (χ24=7.40; P=.12). One-way analysis of variance revealed a significant difference in mean Brief DISCERN scores by source type (F4,23=10.27; P<.001).ConclusionsThe most frequently asked COVID-19 vaccine–related questions pertained to vaccine safety and efficacy. We found that government sources provided the most transparent and highest-quality web-based COVID-19 vaccine–related information. Recognizing common questions and concerns about COVID-19 vaccines may assist in improving vaccination efforts.

Free-form scanning of non-planar appearance with neural trace photography

We propose neural trace photography, a novel framework to automatically learn high-quality scanning of non-planar, complex anisotropic appearance. Our key insight is that free-form appearance scanning can be cast as a geometry learning problem on unstructured point clouds, each of which represents an image measurement and the corresponding acquisition condition. Based on this connection, we carefully design a neural network, to jointly optimize the lighting conditions to be used in acquisition, as well as the spatially independent reconstruction of reflectance from corresponding measurements. Our framework is not tied to a specific setup, and can adapt to various factors in a data-driven manner. We demonstrate the effectiveness of our framework on a number of physical objects with a wide variation in appearance. The objects are captured with a light-weight mobile device, consisting of a single camera and an RGB LED array. We also generalize the framework to other common types of light sources, including a point, a linear and an area light.

The impact of legalization of access to recreational Cannabis on Canadian medical users with Cancer

BackgroundCanada legalized cannabis use for medical purposes in 1999. Legalization of cannabis for recreational purposes in October 2018 offered the opportunity to assess the impact of recreational legalization on cancer patients’ patterns of use to identify learning points that could be helpful to other countries considering similar legislation.MethodTwo identical anonymous cross-sectional surveys were administered to cancer patients in British Columbia 2 months before and 3 months following legalization, with the same eligibility criteria.The prevalence of medical cannabis use, the distribution of symptoms leading to use, the most common types of cannabis products and sources, reasons for stopping using cannabis, and barriers to access were assessed.ResultsThe overall response rate was 27%. Both cohorts were similar regarding age (median = 66 yrs), gender (53% female), and education (approximately 85% of participants had an education level of high school graduation and higher). Respondents had multiple motives for taking cannabis, including to manage multiple symptoms, to treat cancer, and for recreational reasons. The majority of patients in both surveys did not use the legal medical access system.Comparison of the two cohorts showed that after legalization the prevalence of current cannabis use increased by 26% (23·1% to 29·1%, p-value 0·01), including an increased disclosure of recreational motive for use, from 32 to 40%. However, in the post-legalization cohort more Current Users reported problems getting cannabis (18%) than the pre-legalization cohort (8%), (p-value < 0·01). The most common barrier cited was lack of available preferred products, including edibles, as these were only available from illegal dispensaries.ConclusionsResults showed that legalization of cannabis for recreational purposes may have an impact on those who use medical cannabis. Impacts include an increase in prevalence of use; problems accessing preferred products legally; higher cost, and difficulties using a legal access system. The desired goal of regulation in reducing harms from use of illegal cannabis products are unlikely to be achieved if the legal process is less attractive to patients than use of illegal sources.

Plasticizers and bisphenol A in Adyar and Cooum riverine sediments, India: occurrences, sources and risk assessment.

Adyar and Cooum, the two rivers intersecting Chennai city, are exposed to serious pollution due to the release of large quantities of dumped waste, untreated wastewater and sewage. Sediments can act as repository for emerging organic contaminants. Hence, we have monitored the occurrence and risk associated with plasticizers [six phthalic acid esters (PAEs), bis(2-ethyl hexyl adipate) (DEHA)] and bisphenol A (BPA) in surface riverine sediments of Adyar and Cooum rivers from residential/commercial, industrial and electronic waste recycling sites. Σ7plasticizers (PAEs + DEHA) in the Adyar riverine sediment (ARS) and Cooum riverine sediment (CRS) varied between 51.82-1796 and 28.13-856ng/g, respectively. More than three-fourth of Σ7plasticizers came from bis(2-ethylhexyl) phthalate (DEHP), in accordance with the high production and usage of this compound. BPA varied between 10.70-2026 and 7.58-1398ng/g in ARS and CRS, respectively. Average concentrations of plasticizers and BPA were four times higher in electronic waste(e-waste) recycling sites when compared with industrial and residential/commercial sites. BPA and DEHP showed a strong and significant correlation (R2 = 0.7; p < 0.01) in the e-waste sitesthereby indicating common source types. Sites present at close proximity to raw sewage pumping stations contributed to 70% of the total BPA observed in this study. For the derived pore water concentration of plasticizers and BPA, the ecotoxicological risk has been found to be higher in ARS over CRS. However, sediment concentrations in all the sites of ARS and CRS were much below the recommended serious risk concentration for human (SRChuman) and serious risk concentration for ecotoxicological (SRCeco).

AN ANALYSIS OF ACEHNESE EFL STUDENTS’ GRAMMATICAL ERRORS IN WRITING RECOUNT TEXTS

This study aims at finding empirical evidence of the most common types of grammatical errors and sources of errors in recount texts written by the first-year students of SMAS Babul Maghfirah, Aceh Besar. The subject of the study was a collection of students’ personal writing documents of recount texts about their lives experience. The students’ recount texts were analyzed by referring to Betty S. Azar classification and Richard’s theory on sources of errors. The findings showed that the total number of error is 436. Two frequent types of grammatical errors were Verb Tense and Word Choice. The major sources of error were Intralingual Error, Interference Error and Developmental Error respectively. Furthermore, the findings suggest that it is necessary for EFL teachers to apply appropriate techniques and strategies in teaching recount texts, which focus on past tense and language features of the text in order to reduce the possible errors to be made by the students.

Healthy Food Availability Among Food Sources in Rural Maryland Counties

ABSTRACTMost studies examining the association of the food environment and health outcomes have focused on urban settings. However, rural adults and children have high rates of obesity, which may be related to their food environments. This study examines the food environment in 7 rural counties in Maryland. A cross-sectional study was conducted at 244 retail food stores from 2012 to 2013. Data on store-level characteristics were collected and a healthy food availability index (HFAI) ranging from 0 to 31 points was calculated for each store. Convenience stores (18.9%) and other nontraditional stores (16.8%) were the most common store types, and box stores were the least (4.9%). Supermarkets had the highest mean HFAI (24.8), whereas gas stations (8.7) had the lowest; convenience stores were also low (11.1). In rural Maryland, the most common food source types have low healthy food availability, and nontraditional food sources are an important part of the food environment.

Nueva metodología para el cálculo de transformadores en convertidores de potencia multinivel

En este trabajo se presenta una nueva metodología para el correcto diseño de transformadores utilizados en inversoresde potencia multinivel tipo fuente común. La metodología propuesta representa una solución a los problemas dedistorsión en la forma de onda, decaimiento de pulsos en la tensión y pérdida de rendimiento causada por el cálculodel transformador utilizando la metodología convencional. Para validar la metodología se construyen dos prototiposbajo diferentes perspectivas, convencional y propuesta, con el fin de verificar de forma experimental la solución alos problemas descritos y mostrar la mejoría en el rendimiento del convertidor de potencia.

Identifying and quantifying secondhand smoke in source and receptor rooms: logistic regression and chemical mass balance approaches

Identifying and quantifying secondhand tobacco smoke (SHS) that drifts between multiunit homes is critical to assessing exposure. Twenty-three different gaseous and particulate measurements were taken during controlled emissions from smoked cigarettes and six other common indoor source types in 60 single-room and 13 two-room experiments. We used measurements from the 60 single-room experiments for (i) the fitting of logistic regression models to predict the likelihood of SHS and (ii) the creation of source profiles for chemical mass balance (CMB) analysis to estimate source apportionment. We then applied these regression models and source profiles to the independent data set of 13 two-room experiments. Several logistic regression models correctly predicted the presence of cigarette smoke more than 80% of the time in both source and receptor rooms, with one model correct in 100% of applicable cases. CMB analysis of the source room provided significant PM2.5 concentration estimates of all true sources in 9 of 13 experiments and was half-correct (i.e., included an erroneous source or missed a true source) in the remaining four. In the receptor room, CMB provided significant estimates of all true sources in 9 of 13 experiments and was half-correct in another two.

THE COORDINATED RADIO AND INFRARED SURVEY FOR HIGH-MASS STAR FORMATION. II. SOURCE CATALOG

The CORNISH project is the highest resolution radio continuum survey of the Galactic plane to date. It is the 5 GHz radio continuum part of a series of multi-wavelength surveys that focus on the northern GLIMPSE region (10 deg < l < 65 deg), observed by the Spitzer satellite in the mid-infrared. Observations with the Very Large Array in B and BnA configurations have yielded a 1.5" resolution Stokes I map with a root-mean-squared noise level better than 0.4 mJy/beam. Here we describe the data-processing methods and data characteristics, and present a new, uniform catalogue of compact radio-emission. This includes an implementation of automatic deconvolution that provides much more reliable imaging than standard CLEANing. A rigorous investigation of the noise characteristics and reliability of source detection has been carried out. We show that the survey is optimised to detect emission on size scales up to 14" and for unresolved sources the catalogue is more than 90 percent complete at a flux density of 3.9 mJy. We have detected 3,062 sources above a 7-sigma detection limit and present their ensemble properties. The catalogue is highly reliable away from regions containing poorly-sampled extended emission, which comprise less than two percent of the survey area. Imaging problems have been mitigated by down-weighting the shortest spacings and potential artefacts flagged via a rigorous manual inspection with reference to the Spitzer infrared data. We present images of the most common source types found: regions, planetary nebulae and radio-galaxies. The CORNISH data and catalogue are available online at http://cornish.leeds.ac.uk

Long-term monitoring and source apportionment of PM2.5/PM10 in Beijing, China

During 2001-2006, PM2.5 (particle matter with aerodynamic diameter less than 2.5 microns) and PM10 (particle matter with aerodynamic diameter less than 10 microns) were collected at the Beijng Normal University (BNU) site, China, and in 2006, at a background site in Duolun (DL). The long-term monitoring data of elements, ions, and black carbon showed that the major constituents of PM2.5 were black carbon (BC) crustal elements, nitrates, ammonium salts, and sulfates. These five major components accounted for 20%-80% of the total PM2.5. During this period, levels of Pb and S in PM remained rather high, as compared with the levels in other large cities in the world. Source apportionment results suggest that there were 6 common sources for PM2.5 and PM10, i.e., soil dust, vehicular emission, coal combustion, secondary aerosol, industrial emission, and biomass burning. Coal combustion was the largest contributor of PM2.5 with a percentage of 16.6%, whereas soil dust played the most important role in PM10 with a percentage of 27%. In contrast, only three common types of sources could be resolved at the background DL site, namely, soil dust, biomass combustion, and secondary aerosol from combustion sources.

Source Coding With Feed-Forward: Rate-Distortion Theorems and Error Exponents for a General Source

In this work, we consider a source coding model with feed-forward. We analyze a system with a noiseless, feed-forward link where the decoder has knowledge of all previous source samples while reconstructing the present sample. The rate-distortion function for an arbitrary source with feed-forward is derived in terms of directed information, a variant of mutual information. We further investigate the nature of the rate-distortion function with feed-forward for two common types of sources- discrete memory- less sources and Gaussian sources. We then characterize the error exponent for a general source with feed-forward. The results are then extended to feed-forward with an arbitrary delay larger than the block length.

Common-Source Active Clamped Complex Type Converter

This paper presents a novel common-source active clamped complex type converter. This converter is the intermediate isolated bus converter for the distributed power supply system in telecommunications equipment. Using active clamped circuits, the switching loss and switching noise can be reduced by means of the soft switching techniques. By adding an auxiliary winding to the transformer, proposed converter is a common-source type that is direct connection of sources of the two MOSFET switches. As a result, the pulse transformer becomes unnecessary, and the drive circuit is simplified. In the experiment, at 48V ratings input voltage, 36∼72V world wide input voltage, and 12V output voltage, the ZVS operation is performed on main switch and auxiliary switch, and highest efficiency 92.7% is obtained.