377 research outputs found
Interpretation of phase reversals in seismic reflections from attenuating targets
Phase reversals are commonly observed during exploration seismic amplitude-versus-offset analysis, and usually modelled with the Zoeppritz equations. In practice, when multiple fluids are present we often deal with reflections from interfaces having a contrast in both elastic and anelastic properties. In this paper, we present a new phenomenological model for phase reversals in cases in which velocity dispersion and attenuation are present. We demonstrate strong qualitative differences in behaviour between the elastic and anelastic cases, influencing both the amplitude and phase of the reflection coefficient. Analysis of seismic data showing a phase reversal from a gas reservoir in the Vienna basin shows a striking agreement with the modelling. We conclude that the influence of fluid-induced dispersion on reflection data is a significant and measurable phenomenon in cases of practical interest, that recognition of the phenomena may be used as a novel fluid indicator and that frequency-dependent rock physics analysis may be an important tool for both industrial geophysics and seismic monitoring of CO2 storage
Reduction of Injection-Related Risk Behaviors After Emergency Implementation of a Syringe Services Program During an HIV Outbreak
Objective: To describe injection-related HIV risk behaviors preimplementation and postimplementation of an emergency syringe services program (SSP) in Scott County, Indiana, after an HIV outbreak among persons who inject drugs (PWID).
Design: Mixed methods retrospective pre–post intervention analysis.
Methods: We analyzed routine SSP program data collected at first and most recent visit among clients with ≥2 visits, ≥7 days apart from April 4 to August 30, 2015, to quantify changes in injection-related risk behaviors. We also analyzed qualitative data collected from 56 PWID recruited in Scott County to understand factors contributing to these behaviors.
Results: SSP clients included in our analysis (n = 148, 62% of all SSP clients) reported significant (P < 0.001) reductions over a median 10 weeks (range 1–23) in syringe sharing to inject (18%–2%) and divide drugs (19%–4%), sharing other injection equipment (eg, cookers) (24%–5%), and number of uses of the same syringe [2 (interquartile range: 1–4) to 1 (interquartile range: 1–1)]. Qualitative study participants described access to sterile syringes and safer injection education through the SSP, as explanatory factors for these reductions. Injection frequency findings were mixed, but overall suggested no change. The number of syringes returned by SSP clients increased from 0 at first visit to median 57. All qualitative study participants reported using sharps containers provided by the SSP.
Conclusions: Analyses of an SSP program and in-depth qualitative interview data showed rapid reduction of injection-related HIV risk behaviors among PWID post-SSP implementation. Sterile syringe access as part of comprehensive HIV prevention is an important tool to control and prevent HIV outbreaks
Hypoxia drives plastic divergence in cichlid body shape.
Abstract Organisms experience multiple selective agents that can influence phenotypes through heritable and/or plastic changes, often reflecting complex interactions between phenotype and environment. Environmental factors can directly influence phenotypes, but also indirectly affect phenotypic variation when genetic/plastic change in one trait results in correlated genetic/plastic change in another trait. In fishes, body shape is a trait that might be particularly prone to influence from environmental pressures that act on other morphological features. Variation in dissolved oxygen among aquatic environments has a large impact on the size of the gills and brains of fishes. It is likely that dissolved oxygen interacts with other environmental factors to both directly and indirectly influence patterns of body shape variation. We examined effects of dissolved oxygen on body shape variation among populations of an African cichlid fish (Pseudocrenilabrus multicolor) from multiple high-and low-oxygen sites within a single drainage in Uganda. A split-brood laboratory experiment was used to estimate plasticity of gill and brain size, and we used morphometric analyses to identify variation in body shape in F 1 offspring. Several analyses enabled us to identify genetic effects among populations, and effects of oxygen acting either directly on body shape or indirectly through its effects on gill and brain size. A large part of the variation in body shape was due to plastic variation in gill size associated with dissolved oxygen. Fish raised under low oxygen had deeper heads and shorter bodies, and this variation was driven by both direct effects of oxygen and indirect effects of gill size variation. Body shape variation in fishes should reflect interacting effects of multiple environmental factors that act directly or indirectly on morphology. Body shape might be particularly difficult to predict when phenotypes are plastic, because changes among populations would occur rapidly and be unrelated to genetic variation
The argument of the broken pane: Suffragette consumerism and newspapers
Within the cut-throat world of newspaper advertising the newspapers of Britain's Women's Social and Political Union (WSPU) Votes for Women and the Suffragette managed to achieve a balance that has often proved to be an impossible challenge for social movement press—namely the maintenance of a highly political stance whilst simultaneously exploiting the market system with advertising and merchandising. When the militant papers advocated window smashing of West End stores in 1912–1913, the companies who were the target still took advertisements. Why? What was the relationship between news values, militant violence and advertising income? ‘Do-it-yourself’ journalism operated within a context of ethical consumerism and promotionally orientated militancy. This resulted in newspaper connections between politics, commerce and a distinct market profile, evident in the customisation of advertising, retailer dialogue with militants and longer-term loyalty—symptomatic of a wider trend towards newspaper commercialism during this period
Development and Evaluation of a Multi-Year Fractional Surface Water Data Set Derived from Active/Passive Microwave Remote Sensing Data
The sensitivity of Earth’s wetlands to observed shifts in global precipitation and temperature patterns and their ability to produce large quantities of methane gas are key global change questions. We present a microwave satellite-based approach for mapping fractional surface water (FW) globally at 25-km resolution. The approach employs a land cover-supported, atmospherically-corrected dynamic mixture model applied to 20+ years (1992–2013) of combined, daily, passive/active microwave remote sensing data. The resulting product, known as Surface WAter Microwave Product Series (SWAMPS), shows strong microwave sensitivity to sub-grid scale open water and inundated wetlands comprising open plant canopies. SWAMPS’ FW compares favorably (R2 = 91%–94%) with higher-resolution, global-scale maps of open water from MODIS and SRTM-MOD44W. Correspondence of SWAMPS with open water and wetland products from satellite SAR in Alaska and the Amazon deteriorates when exposed wetlands or inundated forests captured by the SAR products were added to the open water fraction reflecting SWAMPS’ inability to detect water underneath the soil surface or beneath closed forest canopies. Except for a brief period of drying during the first 4 years of observation, the inundation extent for the global domain excluding the coast was largely stable. Regionally, inundation in North America is advancing while inundation is on the retreat in Tropical Africa and North Eurasia. SWAMPS provides a consistent and long-term global record of daily FW dynamics, with documented accuracies suitable for hydrologic assessment and global change-related investigations
Circuit dissection of the role of somatostatin in itch and pain
Stimuli that elicit itch are detected by sensory neurons that innervate the skin. This information is processed by the spinal cord; however, the way in which this occurs is still poorly understood. Here we investigated the neuronal pathways for itch neurotransmission, particularly the contribution of the neuropeptide somatostatin. We find that in the periphery, somatostatin is exclusively expressed in Nppb+ neurons, and we demonstrate that Nppb+somatostatin+ cells function as pruriceptors. Employing chemogenetics, pharmacology and cell-specific ablation methods, we demonstrate that somatostatin potentiates itch by inhibiting inhibitory dynorphin neurons, which results in disinhibition of GRPR+ neurons. Furthermore, elimination of somatostatin from primary afferents and/or from spinal interneurons demonstrates differential involvement of the peptide released from these sources in itch and pain. Our results define the neural circuit underlying somatostatin-induced itch and characterize a contrasting antinociceptive role for the peptide
HIV Infection Linked to Injection Use of Oxymorphone in Indiana, 2014-2015
BACKGROUND: In January 2015, a total of 11 new diagnoses of human immunodeficiency virus (HIV) infection were reported in a small community in Indiana. We investigated the extent and cause of the outbreak and implemented control measures.
METHODS: We identified an outbreak-related case as laboratory-confirmed HIV infection newly diagnosed after October 1, 2014, in a person who either resided in Scott County, Indiana, or was named by another case patient as a syringe-sharing or sexual partner. HIV polymerase (pol) sequences from case patients were phylogenetically analyzed, and potential risk factors associated with HIV infection were ascertained.
RESULTS: From November 18, 2014, to November 1, 2015, HIV infection was diagnosed in 181 case patients. Most of these patients (87.8%) reported having injected the extended-release formulation of the prescription opioid oxymorphone, and 92.3% were coinfected with hepatitis C virus. Among 159 case patients who had an HIV type 1 pol gene sequence, 157 (98.7%) had sequences that were highly related, as determined by phylogenetic analyses. Contact tracing investigations led to the identification of 536 persons who were named as contacts of case patients; 468 of these contacts (87.3%) were located, assessed for risk, tested for HIV, and, if infected, linked to care. The number of times a contact was named as a syringe-sharing partner by a case patient was significantly associated with the risk of HIV infection (adjusted risk ratio for each time named, 1.9; P<0.001). In response to this outbreak, a public health emergency was declared on March 26, 2015, and a syringe-service program in Indiana was established for the first time.
CONCLUSIONS: Injection-drug use of extended-release oxymorphone within a network of persons who inject drugs in Indiana led to the introduction and rapid transmission of HIV. (Funded by the state government of Indiana and others.)
Reversing Melanoma Cross-Resistance to BRAF and MEK Inhibitors by Co-Targeting the AKT/mTOR Pathway
The sustained clinical activity of the BRAF inhibitor vemurafenib (PLX4032/RG7204) in patients with BRAF(V600) mutant melanoma is limited primarily by the development of acquired resistance leading to tumor progression. Clinical trials are in progress using MEK inhibitors following disease progression in patients receiving BRAF inhibitors. However, the PI3K/AKT pathway can also induce resistance to the inhibitors of MAPK pathway.The sensitivity to vemurafenib or the MEK inhibitor AZD6244 was tested in sensitive and resistant human melanoma cell lines exploring differences in activation-associated phosphorylation levels of major signaling molecules, leading to the testing of co-inhibition of the AKT/mTOR pathway genetically and pharmacologically. There was a high degree of cross-resistance to vemurafenib and AZD6244, except in two vemurafenib-resistant cell lines that acquired a secondary mutation in NRAS. In other cell lines, acquired resistance to both drugs was associated with persistence or increase in activity of AKT pathway. siRNA-mediated gene silencing and combination therapy with an AKT inhibitor or rapamycin partially or completely reversed the resistance.Primary and acquired resistance to vemurafenib in these in vitro models results in frequent cross resistance to MEK inhibitors, except when the resistance is the result of a secondary NRAS mutation. Resistance to BRAF or MEK inhibitors is associated with the induction or persistence of activity within the AKT pathway in the presence of these drugs. This resistance can be potentially reversed by the combination of a RAF or MEK inhibitor with an AKT or mTOR inhibitor. These combinations should be available for clinical testing in patients progressing on BRAF inhibitors
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