246 research outputs found
Jess\u27s Search for an Understanding of Truth in Fred Chappell\u27s Kirkman Tetralogy
In Fred Chappell’s Kirkman tetralogy, narrator Jess Kirkman synthesizes a multiplicity of perspectives for understanding the nature of truth. Blurring the distinction between art and life, Jess\u27s narrative structure mirrors the imaginative reconstruction of experience; the novels are largely non-chronological emotive interactions with and reflections of his most salient memories and imaginings. Synthesizing an impressive cacophony of voices, Jess\u27s stories both describe and apply the wisdom and tales Jess acquires from and with his family members. Each story informs the prior and the next, and the rhizomatic interaction between language, narrative, and reader explores Jess\u27s numerous identities and understandings as narratives venture through space, time, and imagination
Background CO₂ levels and error analysis from ground-based solar absorption IR measurements in central Mexico
In this investigation we analyze two common optical configurations to retrieve CO₂ total column amounts from solar absorption infrared spectra. The noise errors using either a KBr or a CaF₂ beam splitter, a main component of a Fourier transform infrared spectrometer (FTIR), are quantified in order to assess the relative precisions of the measurements. The configuration using a CaF₂ beam splitter, as deployed by the instruments which contribute to the Total Carbon Column Observing Network (TCCON), shows a slightly better precision. However, we show that the precisions in X ( = 0.2095 ⋅ ) retrieved from > 96 % of the spectra measured with a KBr beam splitter fall well below 0.2 %. A bias in X (KBr − CaF₂) of +0.56 ± 0.25 ppm was found when using an independent data set as reference. This value, which corresponds to +0.14 ± 0.064 %, is slightly larger than the mean precisions obtained. A 3-year X time series from FTIR measurements at the high-altitude site of Altzomoni in central Mexico presents clear annual and diurnal cycles, and a trend of +2.2 ppm yr⁻¹ could be determined
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Lunar and solar FTIR nitric acid measurements at Eureka in winter 2001/2002: comparisons with observations at Thule and Kiruna and with CMAM and SLIMCAT model calculations
For the first time, vertical column measurements of (HNO3) above the Arctic Stratospheric Ozone Observatory (AStrO) at Eureka (80N, 86W), Canada, have been made during polar night using lunar spectra recorded with a Fourier Transform Infrared (FTIR) spectrometer, from October 2001 to March 2002. AStrO is part of the primary Arctic station of the Network for the Detection of Stratospheric Change (NDSC). These measurements were compared with FTIR measurements at two other NDSC Arctic sites: Thule, Greenland (76.5N, 68.8W) and Kiruna, Sweden (67.8N, 20.4E). The measurements were also compared with two atmospheric models: the Canadian
Middle Atmosphere Model (CMAM) and SLIMCAT. This is the first time that CMAM HNO3 columns have been compared with observations in the Arctic. Eureka lunar measurements are in good agreement with solar ones made with the same instrument. Eureka and Thule HNO3 columns are consistent within measurement error. Differences among HNO3 columns measured at Kiruna and those measured at Eureka and Thule can be explained on the basis of the available sunlight hours and the polar vortex location. The comparison of CMAM HNO3 columns with Eureka and Kiruna data shows good agreement, considering CMAM small inter-annual variability. The warm 2001/02 winter with almost no Polar Stratospheric Clouds (PSCs) makes the comparison of the warm climate version of CMAM with these observations a good test for CMAM under no PSC conditions. SLIMCAT captures the magnitude of HNO3 columns at Eureka, and the day-to-day variability, but generally reports higher HNO3 columns than the CMAM climatological mean columns
Mapping poverty using mobile phone and satellite data
Poverty is one of the most important determinants of adverse health outcomes globally, a major cause of societal instability and one of the largest causes of lost human potential. Traditional approaches to measuring and targeting poverty rely heavily on census data, which in most low- and middle-income countries (LMICs) are unavailable or out-of-date. Alternate measures are needed to comp- lement and update estimates between censuses. This study demonstrates how public and private data sources that are commonly available for LMICs can be used to provide novel insight into the spatial distribution of poverty. We evalu- ate the relative value of modelling three traditional poverty measures using aggregate data from mobile operators and widely available geospatial data. Taken together, models combining these data sources providethebest predictive power (highest r 2 ¼ 0.78) and lowest error, but generally models employing mobile data only yield comparable results, offering the potential to measure poverty more frequently and at finer granularity. Stratifying models into urban and rural areas highlights the advantage of using mobile data in urban areas and different data in different contexts. The findings indicate the possibility to estimate and continually monitor poverty rates at high spatial resolution in countries with limited capacity to support traditional methods of datacollection
Mobile Phone Data for Children on the Move: Challenges and Opportunities
Today, 95% of the global population has 2G mobile phone coverage and the
number of individuals who own a mobile phone is at an all time high. Mobile
phones generate rich data on billions of people across different societal
contexts and have in the last decade helped redefine how we do research and
build tools to understand society. As such, mobile phone data has the potential
to revolutionize how we tackle humanitarian problems, such as the many suffered
by refugees all over the world. While promising, mobile phone data and the new
computational approaches bring both opportunities and challenges. Mobile phone
traces contain detailed information regarding people's whereabouts, social
life, and even financial standing. Therefore, developing and adopting
strategies that open data up to the wider humanitarian and international
development community for analysis and research while simultaneously protecting
the privacy of individuals is of paramount importance. Here we outline the
challenging situation of children on the move and actions UNICEF is pushing in
helping displaced children and youth globally, and discuss opportunities where
mobile phone data can be used. We identify three key challenges: data access,
data and algorithmic bias, and operationalization of research, which need to be
addressed if mobile phone data is to be successfully applied in humanitarian
contexts.Comment: 13 pages, book chapte
Antiviral signaling by a cyclic nucleotide activated CRISPR protease
Funding information: M.G. and J.L.S.B. are funded by the Deutsche Forschungsgemeinschaft under Germany’s Excellence Strategy–EXC2151–390873048. M.F.W. acknowledges a European Research Council Advanced Grant (grant number 101018608) and the China Scholarship Council (REF: 202008420207 to H.C.). G.H. is grateful for funding by the Deutsche Forschungsgemeinschaft (grant number HA6805/6-1).CRISPR defense systems such as the well-known DNA-targeting Cas9 and the RNA-targeting type III systems are widespread in prokaryotes1,2. The latter can orchestrate a complex antiviral response that is initiated by the synthesis of cyclic oligoadenylates (cOAs) upon foreign RNA recognition3-5. Among a large set of proteins that were linked to type III systems and predicted to bind cOAs6,7, a CRISPR associated Lon protease (CalpL) stood out to us. The protein contains a sensor domain of the SAVED (SMODS-associated and fused to various effector domains) family7, fused to a Lon protease effector domain. However, the mode of action of this effector was unknown. Here, we report the structure and function of CalpL and show that the soluble protein forms a stable tripartite complex with two further proteins, CalpT and CalpS, that are encoded in the same operon. Upon activation by cA4, CalpL oligomerizes and specifically cleaves the MazF-homolog CalpT, releasing the extracytoplasmic function (ECF) sigma factor CalpS from the complex. This provides a direct connection between CRISPR-based foreign nucleic acid detection and transcriptional regulation. Furthermore, the presence of a cA4-binding SAVED domain in a CRISPR effector reveals an unexpected link to the cyclic oligonucleotide-based antiphage signaling system (CBASS).PostprintPeer reviewe
Trends of ozone total columns and vertical distribution from FTIR observations at eight NDACC stations around the globe
VALIDATION OF ENVISAT-1 LEVEL-2 PRODUCTS RELATED TO LOWER ATMOSPHERE O3 AND NOy CHEMISTRY BY A FTIR QUASI-GLOBAL NETWORK
A coordinated action involving eleven stations of the ground-based Network for Detection of Stratospheric Change (NDSC) equipped with Fourier transform infrared (FTIR) instruments was conducted to contribute to the validation of the three atmospheric chemistry instruments onboard ENVISAT, that are MIPAS, SCIAMACHY and GOMOS.
The target products for validation are total columns of O3, CH4, CO and some important NOy species (NO2, HNO3, NO) and the source gas N2O. Together the eleven stations cover the latitudes between 79 °N and 78°S, including polar, mid -latitude and subtropical and tropical locations. The goal is to contribute to the assessment of the data quality of the aforementioned ENVISAT instruments, from a quasi-global perspective.
The period of intensive ground-based data collection for the benefit of the ENVISAT Validation Commissioning Phase that is dealt with in the present paper is July 15 to December 1, 2002. The FTIR network involved collected a data set corresponding to an equivalent of approximately 400 days of measurements; about three quarter of the data have already been submitted to the ENVISAT Calval database and are included in the present work.
Unfortunately, the distribution of ENVISAT data has been slow and limited. Only a limited number of coincidences has been found for making data inter-comparisons. Therefore, the conclusions drawn in this paper are very preliminary and cover only a limited set of data products from SCIAMACHY only.
Our findings up to now concerning the above mentioned target products are the following: (1) SCIAMACHY near infrared operational products (CO, CH4, N2O) have no scientific meaning yet, (2), the operational SCIAMACHY total vertical O3 column product derived in the ultraviolet window has undergone some improvements with changing versions of the processor(s) but it still underestimates the column by about 5 – 10 %, (3), the operational SCIAMACHY total vertical O3 column product derived in the visible window is unrealistically large, and (3), the operational NO2 total column product from SCIAMACHY seems to largely overestimate the real column, but very few coincidences and large dispersions of the data do inhibit any further conclusion at present.
In a next phase, the same ground-based correlative data set will be exploited to further validate the ENVISAT data as soon as more and reprocessed data will be distributed
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