Cassini Observes the Active South Pole of Enceladus Porco, C. C; Helfenstein, P; Thomas, P. C ...
Science (American Association for the Advancement of Science),
03/2006, Letnik:
311, Številka:
5766
Journal Article
Recenzirano
Cassini has identified a geologically active province at the south pole of Saturn's moon Enceladus. In images acquired by the Imaging Science Subsystem (ISS), this region is circumscribed by a chain ...of folded ridges and troughs at approximately55°S latitude. The terrain southward of this boundary is distinguished by its albedo and color contrasts, elevated temperatures, extreme geologic youth, and narrow tectonic rifts that exhibit coarse-grained ice and coincide with the hottest temperatures measured in the region. Jets of fine icy particles that supply Saturn's E ring emanate from this province, carried aloft by water vapor probably venting from subsurface reservoirs of liquid water. The shape of Enceladus suggests a possible intense heating epoch in the past by capture into a 1:4 secondary spin/orbit resonance.
Abstract
The layered-ruthenate family of materials possess an intricate interplay of structural, electronic and magnetic degrees of freedom that yields a plethora of delicately balanced ground ...states. This is exemplified by Ca
3
Ru
2
O
7
, which hosts a coupled transition in which the lattice parameters jump, the Fermi surface partially gaps and the spins undergo a 90
∘
in-plane reorientation. Here, we show how the transition is driven by a lattice strain that tunes the electronic bandwidth. We apply uniaxial stress to single crystals of Ca
3
Ru
2
O
7
, using neutron and resonant x-ray scattering to simultaneously probe the structural and magnetic responses. These measurements demonstrate that the transition can be driven by externally induced strain, stimulating the development of a theoretical model in which an internal strain is generated self-consistently to lower the electronic energy. We understand the strain to act by modifying tilts and rotations of the RuO
6
octahedra, which directly influences the nearest-neighbour hopping. Our results offer a blueprint for uncovering the driving force behind coupled phase transitions, as well as a route to controlling them.
In 2017, the British Society for Children's Orthopaedic Surgery engaged the profession and all relevant stakeholders in two formal research prioritization processes. In this editorial, we describe ...the impact of this prioritization on funding, and how research in children's orthopaedics, which was until very recently a largely unfunded and under-investigated area, is now flourishing. Establishing research priorities was a crucial step in this process.
Hip fractures are associated with high morbidity, mortality, and costs. One strategy for improving outcomes is to incentivize hospitals to provide better quality of care. We aimed to determine ...whether a pay-for-performance initiative affected hip fracture outcomes in England by using Scotland, which did not participate in the scheme, as a control.
We undertook an interrupted time series study with data from all patients aged more than 60 years with a hip fracture in England (2000 to 2018) using the Hospital Episode Statistics Admitted Patient Care (HES APC) data set linked to national death registrations. Difference-in-differences (DID) analysis incorporating equivalent data from the Scottish Morbidity Record was used to control for secular trends. The outcomes were 30-day and 365-day mortality, 30-day re-admission, time to operation, and acute length of stay.
There were 1 037 860 patients with a hip fracture in England and 116 594 in Scotland. Both 30-day (DID -1.7%; 95% confidence interval (CI) -2.0 to -1.2) and 365-day (-1.9%; 95% CI -2.5 to -1.3) mortality fell in England post-intervention when compared with outcomes in Scotland. There were 7600 fewer deaths between 2010 and 2016 that could be attributed to interventions driven by pay-for-performance. A pre-existing annual trend towards increased 30-day re-admissions in England was halted post-intervention. Significant reductions were observed in the time to operation and length of stay.
This study provides evidence that a pay-for-performance programme improved the outcomes after a hip fracture in England. Cite this article:
2019;101-B:1015-1023.
The aim of this study was to describe temporal trends and survivorship of total hip arthroplasty (THA) in very young patients, aged ≤ 20 years.
A descriptive observational study was undertaken using ...data from the National Joint Registry (NJR) for England, Wales, Northern Ireland and the Isle of Man between April 2003 and March 2017. All patients aged ≤ 20 years at the time of THA were included and the primary outcome was revision surgery. Descriptive statistics were used to summarize the data and Kaplan-Meier estimates calculated for the cumulative implant survival.
A total of 769 THAs were performed in 703 patients. The median follow-up was 5.1 years (interquartile range (IQR) 2.6 to 7.8). Eight patients died and 35 THAs were revised. The use of metal-on-metal (MoM) bearings and resurfacing procedures declined after 2008. The most frequently recorded indications for revision were loosening (20%) and infection (20%), although the absolute risk of these events occurring was low (0.9%). Factors associated with lower implant survival were MoM and metal-on-polyethylene (MoP) bearings and resurfacing arthroplasty ( vs ceramic-on-polyethylene (CoP) and ceramic-on-ceramic (CoC) bearings, p = 0.002), and operations performed by surgeons who undertook few THAs in this age group as recorded in the NJR ( vs those with five or more recorded operations, p = 0.030). Kaplan-Meier estimates showed 96% (95% confidence interval (CI) 94% to 98%) survivorship of implants at five years.
Within the NJR, the overall survival for very young patients undergoing THA exceeded 96% during the first five postoperative years. In the absence of studies that can better account for differences in the characteristics of the patients, surgeons should consider the association between early revision and the type of implant, the number of THAs performed in these patients, and the bearing surface when performing THA in very young patients. Cite this article: Bone Joint J 2018;100-B:1320-9.
Abstract The purpose of this study is to investigate how the use of flavored e-cigarettes varies between youth (12–17 years old), young adults (18–29 years old), and older adults (30 + years old). ...Cross-sectional surveys of school-going youth ( n = 3907) and young adult college students ( n = 5482) in Texas, and young adults and older adults ( n = 6051) nationwide were administered in 2014–2015. Proportions and 95% confidence intervals were used to describe the percentage of e-cigarette use at initiation and in the past 30 days that was flavored, among current e-cigarette users. Chi-square tests were applied to examine differences by combustible tobacco product use and demographic factors. Most e-cigarette users said their first and “usual” e-cigarettes were flavored. At initiation, the majority of Texas school-going youth (98%), Texas young adult college students (95%), and young adults (71.2%) nationwide said their first e-cigarettes were flavored to taste like something other than tobacco, compared to 44.1% of older adults nationwide. Fruit and candy flavors predominated for all groups; and, for youth, flavors were an especially salient reason to use e-cigarettes. Among adults, the use of tobacco flavor at initiation was common among dual users (e-cigarettes + combustible tobacco), while other flavors were more common among former cigarette smokers (P = 0.03). Restricting the range of e-cigarette flavors (e.g., eliminating sweet flavors, like fruit and candy) may benefit youth and young adult prevention efforts. However, it is unclear what impact this change would have on adult smoking cessation.
Abstract
Delineating the origins and properties of antibodies elicited by SARS-CoV-2 infection and vaccination is critical for understanding their benefits and potential shortcomings. Therefore, we ...investigate the SARS-CoV-2 spike (S)-reactive B cell repertoire in unexposed individuals by flow cytometry and single-cell sequencing. We show that ∼82% of SARS-CoV-2 S-reactive B cells harbor a naive phenotype, which represents an unusually high fraction of total human naive B cells (∼0.1%). Approximately 10% of these naive S-reactive B cells share an IGHV1-69/IGKV3-11 B cell receptor pairing, an enrichment of 18-fold compared to the complete naive repertoire. Following SARS-CoV-2 infection, we report an average 37-fold enrichment of IGHV1-69/IGKV3-11 B cell receptor pairing in the S-reactive memory B cells compared to the unselected memory repertoire. This class of B cells targets a previously undefined non-neutralizing epitope on the S2 subunit that becomes exposed on S proteins used in approved vaccines when they transition away from the native pre-fusion state because of instability. These findings can help guide the improvement of SARS-CoV-2 vaccines.
Childhood fractures can have a significant impact on the daily lives of families affecting children's normal activities and parent's work. Wrist fractures are the most common childhood fracture. The ...more serious wrist fractures, that can look visibly bent, are often treated with surgery to realign the bones; but this may not be necessary as bent bones straighten in growing children. The children's radius acute fracture fixation trial (CRAFFT) is a multicentre randomised trial of surgery versus a cast without surgery for displaced wrist fractures. Little is known about how families experience these wrist fractures and how they manage treatment uncertainty. This study aimed to understand families' experience of this injury and what it is like to be asked to include their child in a clinical trial.
Nineteen families (13 mothers, 7 fathers, 2 children) from across the UK participated in telephone interviews. Interviews were audio recorded, transcribed and analysed using reflexive thematic analysis.
Our findings highlight parents' desire to be a good parent through the overarching theme "protecting my injured child". To protect their child after injury, parents endeavoured to make the right decisions about treatment and provide comfort to their child but they experienced ongoing worry about their child's recovery. Our findings show that parents felt responsible for the decision about their child's treatment and their child's recovery. They also reveal the extent to which parents worried about the look of their child's wrist and their need for reassurance that the wrist was healing.
Our findings show that protecting their child after injury can be challenging for parents who need support to make decisions about treatment and confidently facilitate their child's recovery. They also highlight the importance of providing information about treatments, acknowledging parents' concerns and their desire to do the right thing for their child, reassuring parents that their child's wrist will heal and ensuring parents understand what to expect as their child recovers.
Small farmers produce most food in low- and middle-income countries and most small farmers rely on directly or indirectly working equids (WE). The lack of methods and metrics for assessing the role ...of WE hampers realisation of WE contributions. Based on literature review and a survey of WE welfare experts, we propose a framework for optimising WE potential based on two axes of sustainable development goals (SDGs) and value chains. WE contribute especially to earning and sparing income (largely in food production) (SDG 1), but also have roles in accessing health and hygiene services and products (SDG 3 and 5), providing edible products (SDG 2), and benefiting women (SDG 6), with lesser contributions to other SDGs, notably climate action (SDG 13). Experts identified barriers to appropriate appreciation of WE contributions, in order to target actions to overcome them. They found WE are neglected because they belong to farmers who are themselves neglected; because information on WE is inadequate; and, because the unique nature and roles of WE means systems, policies, investors, markets and service providers struggle to cater for them. Harnessing WE to optimally contribute to sustainable development will require generating better evidence on their contributions to SDGs, ensuring better integration into ongoing efforts to attain SDGs, and building the WE capacity among development actors.
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