Explore the vast range of titles available.

Quantifying sector‐resolved methane fluxes in complex emissions environments is challenging yet necessary to improve emissions inventories and guide policy. Here, we separate energy and agriculture sector emissions using a dynamic linear model analysis of methane, ethane, and ammonia data measured at a Northern Colorado site from November 2021 to January 2022. By combining these sector‐apportioned observations with spatially resolved inventories and Bayesian inverse methods, energy and agriculture methane fluxes are optimized across the study's ∼850 km2 sensitivity area. Energy sector fluxes are synthesized with previous literature to evaluate trends in energy sector methane emissions. Optimized agriculture fluxes in the study area were 3.5× larger than inventory estimates; we demonstrate this discrepancy is consistent with differences in the modeled versus real‐world spatial distribution of agricultural sources. These results highlight how sector‐apportioned methane observations can yield multi‐sector inventory optimizations in complex environments. Plain Language Summary Improving our knowledge of the locations, magnitudes, and types of methane sources is important for implementing effective emissions mitigation technologies and regulations. Methane emissions are often challenging to quantify because a wide variety of sources can emit methane, and these disparate sources are often intermingled. We demonstrate how a dynamic linear model can use multi‐month time series of two tracer gases, ethane and ammonia, to effectively separate methane emissions from the energy and agriculture sectors. Incorporating these data into a Bayesian inverse analysis refines the magnitude and distribution of methane fluxes from each sector. Our analysis reveals that methane from agriculture is several times higher than inventory estimates. While this is in part due to the spatial distribution of sources, more monitoring is needed to improve agriculture emissions factors. Energy sector emissions factors optimized in this work are consistent with other regional studies of energy sector methane emissions. A synthesis of these works demonstrates a regional decline in energy sector emissions despite a concomitant increase in oil and gas extraction; however, current emissions are similar to 2008 estimates. Key Points A dynamic linear model apportions energy and agriculture methane emissions from multi‐month trace gas measurements in Northern Colorado An estimated 0.4 ± 0.2 kg CH4 are emitted per barrel of oil equivalent produced, yielding a Wattenberg Field emission rate of 15 Mg CH4/hr Optimized agriculture methane emissions are higher than inventory predictions, in part due to mislocated fluxes in the inventory

We present an open-path mid-infrared dual-comb spectroscopy (DCS) system capable of precise measurement of the stable water isotopologues H216O and HD16O. This system ran in a remote configuration at a rural test site for 3.75 months with 60 % uptime and achieved a precision of < 2 ‰ on the normalized ratio of H216O and HD16O (δD) in 1000 s. Here, we compare the δD values from the DCS system to those from the National Ecological Observatory Network (NEON) isotopologue point sensor network. Over the multi-month campaign, the mean difference between the DCS δD values and the NEON δD values from a similar ecosystem is < 2 ‰ with a standard deviation of 18 ‰, which demonstrates the inherent accuracy of DCS measurements over a variety of atmospheric conditions. We observe time-varying diurnal profiles and seasonal trends that are mostly correlated between the sites on daily timescales. This observation motivates the development of denser ecological monitoring networks aimed at understanding regional- and synoptic-scale water transport. Precise and accurate open-path measurements using DCS provide new capabilities for such networks.

While the glow of a sodium vapor lamp or the crisp reds in autumn leaves are eye-catching examples of transitions between atomic and molecular energy levels (hv ~2-3 eV), it is arguably the much lower energy, thermally populated intermolecular \"bath\" states (hv ~10⁻⁵-10⁻² eV) that contribute most directly to the physical properties of matter. Although invisible to the human eye, in this thesis we study fundamentals of these low-energy interactions with two complementary techniques: chirped pulse microwave spectroscopy and nonlinear single-shot terahertz (THz) Kerr effect spectroscopy.In the first section, we apply chirped pulse-Fourier transform microwave (CP-FTMW) spectroscopy from 8-16 GHz to study fundamental hydrogen bonding motifs in gas phase alcohol water dimers. Hydrogen bonding is ubiquitous in nature and directly contributes to a range of phenomena from phase transitions in water to solvation of ions to enzymatic activity. Our focus on gas phase dimers reduces the spectral ambiguity arising in condensed phase samples, where inhomogeneous and homogeneous broadening can hamper observation of conserved intermolecular interaction motifs. The hydrogen bonding conformation of two alcohol-water dimers, n-propanol-water and isopropanol-water, were characterized. Both were found to adopt a shared water donor-alcohol acceptor conformation.The following sections use nonlinear THz spectroscopy from 0.1-10 THz to investigate molecular dynamics in the condensed phase. We focus on halogenated methane liquids, whose intense intramolecular vibrational modes are commensurate in energy to the intermolecular bath states. One central goal of this section was developing a technique to more rapidly collect nonlinear, multi-dimensional data from liquid systems. To that end, we developed a single-shot measurement approach using a reflective nickel echelon mirror and a high frame rate camera. With this new device we achieved an order of magnitude reduction in experimental integration times. High resolution, nonlinear multi-dimensional THz studies of several halogenated methane liquids and materials were produced as a result. From these data, we identified important spectral contributions from the experimental instrument response function.

Napster's website appeared in 1999, and much has since been written about the future of copyright law; whereas the music industry and artists portrayed themselves as Napster's victims, Napster portrayed its users as a community sharing an interest in music. Examines how the moral identities of both artists and Napster users have been constructed in the rhetoric between Napster and the Recording Industry Association of America, RIAA. Discusses how artists were affected by Napster, mentioning the authorship theories of Mark Rose and Michel Foucault, where the loss of centralised control over artists' works constitutes loss of control over their identities. Moves on to the RIAA's use of the \"piracy\" concept in regard to Napster and its users, Napster's defences, and how this discourse illustrates the common slide from behaviour to identity.

Nonlinear THz-THz-Raman (TTR) liquid spectroscopy offers new possibilities for studying and understanding condensed-phase chemical dynamics. Although TTR spectra carry rich information about the systems under study, the response is encoded in a three-point correlation function comprising of both dipole and polarizability elements. Theoretical methods are necessary for the interpretation of the experimental results. In this work, we study the liquid-phase dynamics of bromoform, a polarizable molecule with a strong TTR response. Previous work based on reduced density matrix (RDM) simulations suggests that unusually large multi-quanta dipole matrix elements are needed to understand the measured spectrum of bromoform. Here, we demonstrate that a self-consistent definition of the time coordinates with respect to the reference pulse leads to a simplified experimental spectrum. Furthermore, we analytically derive a parametrization for the RDM model by integrating the dipole and polarizability elements to the 4th order in the normal modes, and we enforce inversion symmetry in the calculations by numerically cancelling the components of the response that are even with respect to the field. The resulting analysis eliminates the need to invoke large multi-quanta dipole matrix elements to fit the experimental spectrum; instead, the experimental spectrum is recovered using RDM simulations with dipole matrix parameters that are in agreement with independent ab initio calculations. The fundamental interpretation of the TTR signatures in terms of coupled intramolecular vibrational modes remains unchanged from the previous work.

The popular recording artist Prince is known for his ability to fuse musical styles considered mutually exclusive on the basis of race—funk and new-wave, R&B and hard rock. Prince has also made a name for himself by moving between different identities—sexual savant, devout man of god, androgynous sprite—a strategy that fit the 1980s, an era of shifting identity politics. This dissertation expands on previous scholarly work, which has claimed Prince as a quintessentially “post-modern” figure, by showing how his music manifests a history of the struggle for African-American self-representation. As an artist well versed in American pop history and deeply engaged with the black church, Prince was bringing the liberatory strategies of African-American culture to bear even as he de-constructed gender and sexuality. This dissertation takes a fresh approach to the question of music and identity: by analyzing Prince's music with an ear for particular genre references, I present a snapshot of racial politics, music, and American society during a time period that few scholars have yet addressed. Musical genre is the discursive arena in which popular musicians navigate identity and history, and in each of my chapters I have focused on how Prince manipulates genre references, taking instrumental idioms as the signifiers of genre and identity. My introduction considers Prince's use of the guitar, a “white” rock instrument; chapter one deals with keyboard synthesizers, and how Prince blended R&B horn idioms with new-wave music; chapter two discusses the relationship between funk drumming and black identity, exploring Prince's symphonic transformations of the funk and his ambivalence to hip-hop. Chapter three connects Prince's vocal styles to gospel music and the cosmology of the black church; and chapter four details how Prince re-integrated horns into his music, engaging with jazz and R&B as a way to reclaim black musical history. In its blend of musicology, African-American history, and cultural studies, this dissertation captures the sounds of racial politics of the 1980s and 90s, as heard through the music of one of the era's most popular artists as he worked to transform and transcend those politics.

We demonstrate that halogenated methane 2D-Terahertz Terahertz Raman (2D-TTR) spectra are determined by the complicated structure of the instrument response function (IRF) along \\(f_1\\) and by the molecular coherences along \\(f_2\\). Experimental improvements have helped increase the resolution and dynamic range of the measurements, including accurate THz pulse shape characterization. Sum-frequency excitations convolved with the IRF are found to quantitatively reproduce the 2D-TTR signal. A new Reduced Density Matrix model which incorporates sum-frequency pathways, with linear and harmonic operators fully supports this (re)interpretation of the 2D-TTR spectra.

Escherichia coli O157 was first identified as a human pathogen in 1982. One of several Shiga toxin-producing serotypes known to cause human illness, the organism probably evolved through horizontal acquisition of genes for Shiga toxins and other virulence factors. E coli O157 is found regularly in the faeces of healthy cattle, and is transmitted to humans through contaminated food, water, and direct contact with infected people or animals. Human infection is associated with a wide range of clinical illness, including asymptomatic shedding, non-bloody diarrhoea, haemorrhagic colitis, haemolytic uraemic syndrome, and death. Since laboratory practices vary, physicians need to know whether laboratories in their area routinely test for E coli O157 in stool specimens. Treatment with antimicrobial agents remains controversial: some studies suggest that treatment may precipitate haemolytic uraemic syndrome, and other studies suggest no effect or even a protective effect. Physicians can help to prevent E coli O157 infections by counselling patients about the hazards of consuming undercooked ground meat or unpasteurised milk products and juices, and about the importance of handwashing to prevent the spread of diarrhoeal illness, and by informing public-health authorities when they see unusual numbers of cases of bloody diarrhoea or haemolytic uraemic syndrome.

Missense mutations in the TREM2 gene are associated with increased risk of Alzheimer's disease (AD). Aβ is a known ligand of TREM2 binding directly and activating a signalling pathway involving PLCG2. TREM2 itself signals through its association with DAP12 and recruits SYK through its cytosolic immune-receptor tyrosine-based activation motifs. This study will provide insights into relevant TREM2-PLCG2-associated cellular processes to help to identify novel interacting proteins and dissect cellular mechanisms involved in AD. Aβ and anti-TREM2 activating antibody were used to stimulate TREM2 signalling in mouse microglia followed by western blotting to interrogate the phosphorylation state of various interactors under basal and stimulated conditions. Co-IP and Immunofluorescence studies were performed to investigate protein interactors in this signalling cascade. Migration and Aβ engulfment assays were used as downstream functional readouts of TREM2 stimulation. Results are representative of at least three independent biological replicate experiments. We discovered that the endogenous TREM2-DAP12-PLCG2 signaling complex interacts with numerous novel high affinity components in microglia. We found that the levels of phospho-SYK (Tyr525/526) and non-canonical phospho-tyrosines in PLCG2 were significantly increased by TREM-2 activation. Increased Phospho-PLCG2 levels triggered changes in microglia function reflected in functional assays such as cell migration and cargo engulfment assays. We discovered that stimulation of TREM2 in microglia led to a novel signalling cascade involving PLCG2 and other proteins which mediated important microglia functions. Some of these proteins are components of the B cell receptor signaling machinery acting via PLCG2 while others are known/new AD-related risk genes. The elucidation of the TREM2-PLCG2 pathway and its downstream signalling partners provides important insights into the mechanisms of normal microglia function and in the pathogenesis of AD.

We used molecular subtyping to investigate an outbreak of listeriosis involving residents of 24 US states. We defined a case as infection with Listeria monocytogenes serotype 4b yielding one of several closely related patterns when subtyped by pulsed-field gel electrophoresis. Patients infected with strains yielding different patterns were used as controls. A total of 108 cases were identified with 14 associated deaths and four miscarriages or stillbirths. A case-control study implicated meat frankfurters as the likely source of infection (OR 17·3, 95% CI 2·4–160). The outbreak ended abruptly following a manufacturer-issued recall, and the outbreak strain was later detected in low levels in the recalled product. A second strain was recovered at higher levels but was not associated with human illness. Our findings suggest that L. monocytogenes strains vary widely in virulence and confirm that large outbreaks can occur even when only low levels of contamination are detected in sampled food. Standardized molecular subtyping and coordinated, multi-jurisdiction investigations can greatly facilitate detection and control of listeriosis outbreaks.