5,511 research outputs found

    Significant Tropospheric O3 Production from Extratropical Forest Fires:When? When Not?

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    There is significant controversy on whether extratropical fires contribute importantly to widespread ozone productionabsent the addition of urban pollutant nitrogen oxides (Jaffe and Widger, 2012, Singh et al., 2012,2013). Wereport a significant range of O3 production early in the fire plume history and report controls on which notable O3production occurs. The current data set is the airborne observations made on board NASAs highly instrumentedDC-8 aircraft during the ARCTAS (2008) and SEAC4RS (2013) campaigns within the Western United States. Aclear analysis of fire emissions was aided considerably by MERET (a Mixed Effects Regressions Emissions Technique).This technique allows consistent emission factors and enhancement ratios for O3 for individual aircraftsamples largely free from uncertainties resulting from mixing and entrainment which plague many published estimates.(Yokelson et al, 2013, Chatfield and Andreae, 2016). We find support for the reasonable idea that the ratioof nitrogen oxides (NOx) to volatile organic carbon (VOC) emissions controls new O3 production. The evidence isfor significant O3 production from high-fuel-nitrogen fuels (as evidenced by acetonitrile) and extremely hot largefires (like the Yosemite Rim Fire of 2013 which we analyze), while others do not. VOC emissions factors varysignificantly from fire to fire (and from different samples in the Rim Fire). Relative CO production (aka modifiedcombustion efficiency) is only one factor describing VOC emissions factors

    Investigating client dropout from psychotherapeutic treatments for personality disorders

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    Dropout from therapy for personality disorder (PD) represents a clinically-important but poorly understood phenomenon in the existing literature. The present grounded theory study explores the experiences of clients with PD, and their therapists, of treatment dropout from a National Health Service outpatient psychotherapy service, specialising in psychodynamic interventions for PD. Pre-therapy questionnaires for 20 clients were initially reviewed to generate hypotheses about the differences between treatment dropouts and completers, before a focus group was conducted with six therapists to explore their beliefs about and experiences of client dropout. Finally, six individual interviews were conducted with clients with PD, five of whom had dropped out from therapy at the host service. The final model highlighted the importance of clients’ treatment expectations, how they perceived their therapist’s behaviour, and their interpersonal history in making decisions about whether to stay in or drop out of therapy. The impact of therapy endings upon clients is also discussed, as well as therapists’ beliefs about managing complex clients, both individually and within a team, under current financial and clinical pressures. The findings are then discussed in relation to existing theory and research, and the clinical implications and limitations of the study are presented

    AXR1 acts after lateral bud formation to inhibit lateral bud growth in Arabidopsis

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    The AXR1 gene of Arabidopsis is required for many auxin responses. The highly branched shoot phenotype of mature axr1 mutant plants has been taken as genetic evidence for a role of auxin in the control of shoot branching. We compared the development of lateral shoots in wild-type Columbia and axr1-12 plants. In the wild type, the pattern of lateral shoot development depends on the developmental stage of the plant. During prolonged vegetative growth, axillary shoots arise and develop in a basal-apical sequence. After floral transition, axillary shoots arise rapidly along the primary shoot axis and grow out to form lateral inflorescences in an apical-basal sequence. For both patterns, the axr1 mutation does not affect the timing of axillary meristem formation; however, subsequent lateral shoot development proceeds more rapidly in axr1 plants. The outgrowth of lateral inflorescences from excised cauline nodes of wild-type plants is inhibited by apical auxin. axr1-12 nodes are resistant to this inhibition. These results provide evidence for common control of axillary growth in both patterns, and suggest a role for auxin during the late stages of axillary shoot development following the formation of the axillary bud and several axillary leaf primordia

    Emissions Relationships in Western Forest Fire Plumes: I. Reducing the Effect of Mixing Errors on Emission Factors

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    Studies of emission factors from biomass burning using aircraft data complement the results of lab studies and extend them to conditions of immense hot conflagrations. We illustrate and discuss emission relationships for 422 individual samples from many forest-fire plumes in the Western US. The samples are from two NASA investigations: ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) and SEAC4RS (Studies of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys). This work provides sample-by-sample enhancement ratios (EnRs) for 23 gases and particulate properties. Many EnRs provide candidates for emission ratios (ERs, corresponding to the EnR at the source) when the origin and degree of transformation is understood and appropriate. From these, emission factors (EFs) can be estimated when the fuel dry mass consumed is known or can be estimated using the carbon mass budget approach. This analysis requires understanding the interplay of mixing of the plume with surrounding air. Some initial examples emphasize that measured C(tot) = CO2 + CO in a fire plume does not necessarily describe the emissions of the total carbon liberated in the flames, C(burn). Rather, it represents C(tot) = C(burn) + C(bkgd), which includes possibly varying background concentrations for entrained air. Consequently, we present a simple theoretical description for plume entrainment for multiple tracers from flame to hundreds of kilometers downwind and illustrate some intrinsic linear behaviors. The analysis suggests a Mixed Effects Regression Emission Technique (MERET), which can eliminate occasional strong biases associated with the commonly used normalized excess mixing ratio (NEMR) method. MERET splits C(tot) to reveal C(burn) by exploiting the fact that C(burn) and all tracers respond linearly to dilution, while each tracer has consistent EnR behavior (slope of tracer concentration with respect to C(burn)). The two effects are separable. Two or three or preferably more emission indicators are required as a minimum; here we used ten. Limited variations in the EnRs for each tracer can be incorporated and the variations and co-variations analyzed. The percentage CO yield (or the modified combustion efficiency) plays some role. Other co-relationships involving nitrogen and organic classes are more prominent; these have strong relationships to the C(burn) to O3 emission relationship. In summary, MERET allows fine spatial resolution (EnRs for individual observations) and comparison of similar plumes distant in time and space. Alkene ratios provide us with an approximate photochemical timescale. This allows discrimination and definition, by fire situation, of ERs, allowing us to estimate emission factors

    The Science and Art of Transcription

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    Qualitative researchers may view interview transcription as a burdensome way to initiate data analysis. I initially struggled with self-transcription, and, while I found it became easier over time, I continue to experiment with methods to improve my efficiency and my ability to capture more data. During this paper presentation, I will demonstrate technologies which, used alone or in combination, may encourage researcher comfort with transcription and facilitate creative presentation of data

    Intrusion Detection for Smart Grid Communication Systems

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    Transformation of the traditional power grid into a smart grid hosts an array of vulnerabilities associated with communication networks. Furthermore, wireless mediums used throughout the smart grid promote an environment where Denial of Service (DoS) attacks are very effective. In wireless mediums, jamming and spoofing attack techniques diminish system operations thus affecting smart grid stability and posing an immediate threat to Confidentiality, Integrity, and Availability (CIA) of the smart grid. Intrusion detection systems (IDS) serve as a primary defense in mitigating network vulnerabilities. In IDS, signatures created from historical data are compared to incoming network traffic to identify abnormalities. In this thesis, intrusion detection algorithms are proposed for attack detection in smart grid networks by means of physical, data link, network, and session layer analysis. Irregularities in these layers provide insight to whether the network is experiencing genuine or malicious activity

    President\u27s Forum—A Return to New England

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    It is a great professional and personal honor to address you as the newly installed fifty-seventh President of the U.S. Naval War College. No other institution has contributed more to the history and heritage of our great Navy than this remarkable school. Located along the shores of beautiful Narragansett Bay, this College has been the nexus of nautical scholarship, cutting-edge research, and maritime-security cooperation for 135 years

    Is the Hospitality Industry Ready for the New Lease Accounting Standards?

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    The days where companies can use off-balance sheet leases are coming to an end. The new lease accounting standards, ASU 842 and IFRS 16, released in early 2016, will be effective, respectively, on December 15, 2018, and January 1, 2019. Under the new standards, virtually all leases will be recognized on a lessee’s balance sheet. Hence, financial statements and ratios of companies that heavily use off-balance sheet leases will be considerably impacted. Our analysis of the off-balance sheet leases by the hospitality industry indicates that hospitality companies do extensively use these operating leases, which amounted to 51% of their assets in 2015. The expected widespread unfavorable impact on a lessee’s debt ratios and interest coverages could also affect a hospitality company’s borrowing rates and debt covenants. Given that the implementation is most likely time consuming, not just costly, the earlier the hospitality companies are prepared for the new standards the better
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