313 research outputs found
E151 (sym15), A Pleiotropic Mutant of Pea (Pisum sativum L.), Displays Low Nodule Number, Enhanced Mycorrhizae, Delayed Lateral Root Emergence, and High Root Cytokinin Levels
In legumes, the formation of rhizobial and mycorrhizal root symbioses is a highly regulated process which requires close communication between plant and microorganism. Plant mutants that have difficulties establishing symbioses are valuable tools for unravelling the mechanisms by which these symbioses are formed and regulated. Here E151, a mutant of Pisum sativum cv. Sparkle, was examined to characterize its root growth and symbiotic defects. The symbioses in terms of colonization intensity, functionality of micro-symbionts, and organ dominance were compared between the mutant and wild type. The endogenous cytokinin (CK) and abscisic acid (ABA) levels and the effect of the exogenous application of these two hormones were determined. E151 was found to be a low and delayed nodulator, exhibiting defects in both the epidermal and cortical programmes though a few mature and functional nodules develop. Mycorrhizal colonization of E151 was intensified, although the fungal functionality was impaired. Furthermore, E151 displayed an altered lateral root (LR) phenotype compared with that of the wild type whereby LR emergence is initially delayed but eventually overcome. No differences in ABA levels were found between the mutant and the wild type, but non-inoculated E151 exhibited significantly high CK levels. It is hypothesized that CK plays an essential role in differentially mediating the entry of the two micro-symbionts into the cortex; whereas it would inhibit the entry of the rhizobia in that tissue, it would promote that of the fungus. E151 is a developmental mutant which may prove to be a useful tool in further understanding the role of hormones in the regulation of beneficial root symbioses
Everyday curation? Attending to data, records and record keeping in the practices of self-monitoring
This paper is concerned with everyday data practices, considering how people record data produced through self-monitoring. The analysis unpacks the relationships between taking a measure, and making and reviewing records. The paper is based on an interview study with people who monitor their blood pressure and/or body mass index/weight. Animated by discussions of ‘data power’ which are, in part, predicated on the flow and aggregation of data, we aim to extend important work concerning the everyday constitution of digital data. In the paper, we adopt and develop the idea of curation as a theory of attention. We introduce the idea of discerning work to characterise the skilful judgements people make about which readings they record, how readings are presented, and about the records they retain and those they discard. We suggest self-monitoring produces partial data, both in the sense that it embodies these judgements, and also because monitoring might be conducted intermittently. We also extend previous analyses by exploring the broad set of materials, digital and analogue, networked and not networked, involved in record keeping to consider the different ways these contributed to regulating attention to self-monitoring. By paying attention to which data is recorded and the occasions when data is not recorded, as well as the ways data is recorded, the research provides specificity to the different ways in which self-monitoring data may or may not flow or contribute to big data sets. We argue that ultimately our analysis contributes to nuancing our understanding of ‘data power’
Navigating standards, encouraging interconnections: infrastructuring digital health platforms
Apps, websites and networked devices now offer to help consumers produce, access and share health knowledge, precipitating social scientific concern over the consequences of these so-called digital health platforms. This paper makes a novel contribution to this literature, taking up a recent call from Plantin et al. to adopt an infrastructural lens in exploring platforms. It argues, through empirical analysis of digital health platforms of different sizes, ages and nationalities, that this conceptual tool is necessary to surface the work entailed in creating and sustaining digital health platforms. Additionally, we suggest that the social scientific literature on platforms–and initial efforts to explore their infrastructural qualities–frequently focus too strongly on the dominant technology companies. Instead, we emphasise the value of drawing emergent companies’ platforms into empirical purview through returning to some of the infrastructures literature that informs Plantin et al.–particularly Susan Leigh Star and colleagues. We demonstrate empirically the importance of looking at standards as part of infrastructure building, and the broader set of interconnections between different actors and materials within an infrastructure. In doing so, we demonstrate the value of an infrastructural lens for understanding the density of interconnections that characterise digital health and propose some orientating questions for further enquiry into the infrastructural qualities of platforms
Efficacy of Chronic Antidepressant Treatments in a New Model of Extreme Anxiety in Rats
Animal models of anxious disorders found in humans, such as panic disorder and posttraumatic stress disorder, usually include spontaneous and conditioned fear that triggers escape and avoidance behaviors. The development of a panic disorder model with a learned component should increase knowledge of mechanisms involved in anxiety disorders. In our ethological model of extreme anxiety in the rat, forced apnea was combined with cold water vaporization in an inescapable situation. Based on the reactions of vehicle controls, behaviors involved in paroxysmic fear were passive (freezing) and active (jumping) reactions. Our results show that subchronic fluoxetine (5 mg/kg, IP, 21 days) and imipramine (10 mg/kg, IP, 14 days) administration alleviated freezing and jumping behaviors, whereas acute fluoxetine (1 mg/kg, IP) provoked opposite effects. Acute low dose of diazepam (1 mg/kg, IP) was not effective, whereas the higher dose of 3 mg/kg, IP, and clonazepam (1 mg/kg, IP) only had an effect on jumping. Paroxysmic fear generated in this experimental condition may therefore mimic the symptomatology observed in patients with anxiety disorders
CLEAR I: Ages and Metallicities of Quiescent Galaxies at Derived from Deep Hubble Space Telescope Grism Data
We use deep \textit{Hubble Space Telescope} spectroscopy to constrain the
metallicities and (\editone{light-weighted}) ages of massive () galaxies selected to have quiescent stellar
populations at . The data include 12--orbit depth coverage with the
WFC3/G102 grism covering ~\AA\, at a spectral
resolution of taken as part of the CANDELS Lyman- Emission
at Reionization (CLEAR) survey. At , the spectra cover important
stellar population features in the rest-frame optical. We simulate a suite of
stellar population models at the grism resolution, fit these to the data for
each galaxy, and derive posterior likelihood distributions for metallicity and
age. We stack the posteriors for subgroups of galaxies in different redshift
ranges that include different combinations of stellar absorption features. Our
results give \editone{light-weighted ages of ~Gyr,
~Gyr, ~Gyr, and
~Gyr, \editone{for galaxies at , 1.2,
1.3, and 1.6. This} implies that most of the massive quiescent galaxies at
\% of their stellar mass by a redshift of }. The
posteriors give metallicities of \editone{~, ~, ~, and ~}. This is evidence
that massive galaxies had enriched rapidly to approximately Solar metallicities
as early as .Comment: 32 pages, 23 figures, Resubmited to ApJ after revisions in response
to referee repor
A machine learning approach enables quantitative measurement of liver histology and disease monitoring in NASH
BACKGROUND AND AIMS: Manual histological assessment
is currently the accepted standard for diagnosing and monitoring
disease progression in NASH, but is limited by variability in
interpretation and insensitivity to change. Thus, there is a critical
need for improved tools to assess liver pathology in order
to risk stratify NASH patients and monitor treatment response.
APP ROA CH AND RESULT S: Here, we describe a machine
learning (ML)-based
approach to liver histology assessment,
which accurately characterizes disease severity and heterogeneity,
and sensitively quantifies treatment response in NASH. We use
samples from three randomized controlled trials to build and
then validate deep convolutional neural networks to measure
key histological features in NASH, including steatosis, inflammation,
hepatocellular ballooning, and fibrosis. The ML-based
predictions showed strong correlations with expert pathologists
and were prognostic of progression to cirrhosis and liver-related
clinical events. We developed a heterogeneity-sensitive
metric
of fibrosis response, the Deep Learning Treatment Assessment
Liver Fibrosis score, which measured antifibrotic treatment effects
that went undetected by manual pathological staging and
was concordant with histological disease progression.
CONCLUSIONS: Our ML method has shown reproducibility
and sensitivity and was prognostic for disease progression,
demonstrating the power of ML to advance our
understanding of disease heterogeneity in NASH, risk stratify
affected patients, and facilitate the development of therapies.
(Hepatology 2021;74:133-147)
Using Practice Facilitation to Increase Rates of Colorectal Cancer Screening in Community Health Centers, North Carolina, 2012–2013: Feasibility, Facilitators, and Barriers
INTRODUCTION: Practice facilitation involves trained individuals working with practice staff to conduct quality improvement activities and support delivery of evidence-based clinical services. We examined the feasibility of using practice facilitation to assist federally qualified health centers (FQHCs) to increase colorectal cancer screening rates in North Carolina.
METHODS: The intervention consisted of 12 months of facilitation in 3 FQHCs. We conducted chart audits to obtain data on changes in documented recommendation for colorectal cancer screening and completed screening. Key informant interviews provided qualitative data on barriers to and facilitators of implementing office systems.
RESULTS: Overall, the percentage of eligible patients with a documented colorectal cancer screening recommendation increased from 15% to 29% (P < .001). The percentage of patients up to date with colorectal cancer screening rose from 23% to 34% (P = .03). Key informants in all 3 clinics said the implementation support from the practice facilitator was critical for initiating or improving office systems and that modifying the electronic medical record was the biggest challenge and most time-consuming aspect of implementing office systems changes. Other barriers were staff turnover and reluctance on the part of local gastroenterology practices to perform free or low-cost diagnostic colonoscopies for uninsured or underinsured patients.
CONCLUSION: Practice facilitation is a feasible, acceptable, and promising approach for supporting universal colorectal cancer screening in FQHCs. A larger-scale study is warranted
The drugs don't sell: DIY heart health and the over-the-counter statin experience
This paper draws on a study of over-the-counter statins to provide a critical account of the figure of the ‘pharmaceutical consumer’ as a key actor in the pharmaceuticalisation literature. A low dose statin, promising to reduce cardiovascular risk, was reclassified to allow sale in pharmacies in the UK in 2004. We analysed professional and policy debates about the new product, promotional and sales information, and interviews with consumers and potential consumers conducted between 2008 and 2011, to consider the different consumer identities invoked by these diverse actors.
While policymakers constructed an image of ‘the citizen-consumer’ who would take responsibility for heart health through exercising the choice to purchase a drug that was effectively rationed on the NHS and medical professionals raised concerns about ‘a flawed consumer’ who was likely to misuse the product, both these groups assumed that there would be a market for the drug. By contrast, those who bought the product or potentially fell within its target market might appear as ‘health consumers’, seeking out and paying for different food and lifestyle products and services, including those targeting high cholesterol. However, they were reluctant ‘pharmaceutical consumers’ who either preferred to take medication on the advice of a doctor, or sought to minimize medicine use.
In comparison to previous studies, our analysis builds understanding of individual consumers in a market, rather than collective action for access to drugs (or, less commonly, compensation for adverse effects). Where some theories of pharmaceuticalisation have presented consumers as creating pressure for expanding markets, our data suggests that sociologists should be cautious about assuming there will be demand for new pharmaceutical products, especially those aimed at prevention or asymptomatic conditions, even in burgeoning health markets
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