6,690 research outputs found
Experimental reduction of simulated lunar glass by carbon and hydrogen and implications for lunar base oxygen production
The most abundant element in lunar rocks and soils is oxygen which makes up approximately 45 percent by weight of the typical lunar samples returned during the Apollo missions. This oxygen is not present as a gas but is tightly bound to other elements in mineral or glass. When people return to the Moon to explore and live, the extraction of this oxygen at a lunar outpost may be a major goal during the early years of operation. Among the most studied processes for oxygen extraction is the reduction of ilmenite by hydrogen gas to form metallic iron, titanium oxide, and oxygen. A related process is proposed which overcomes some of the disadvantages of ilmenite reduction. It is proposed that oxygen can be extracted by direct reduction of native lunar pyroclactic glass using either carbon, carbon monoxide, or hydrogen. In order to evaluate the feasibility of this proposed process a series of experiments on synthetic lunar glass are presented. The results and a discussion of the experiments are presented
Ultrahigh energy neutrino scattering: an update
We update our estimates of charged and neutral current neutrino total cross
sections on isoscalar nucleons at ultrahigh energies using a global (x, Q^2)
fit, motivated by the Froissart bound, to the F_2 (electron-proton) structure
function utilizing the most recent analysis of the complete ZEUS and H1 data
sets from HERA I. Using the large Q^2, small Bjorken-x limits of the "wee"
parton model, we connect the ultrahigh energy neutrino cross sections directly
to the large Q^2, small-x extrapolation of our new fit, which we assume
saturates the Froissart bound. We compare both to our previous work, which
utilized only the smaller ZEUS data set, as well as to recent results of a
calculation using the ZEUS-S based global perturbative QCD parton distributions
using the combined HERA I results as input. Our new results substantiate our
previous conclusions, again predicting significantly smaller cross sections
than those predicted by extrapolating pQCD calculations to neutrino energies
above 10^9 GeV.Comment: 8 pages, 1 figure, 3 table
Understanding the difference, makes the difference: perceptions of Black and Minoritised ethnic occupational therapists on mentoring
Introduction Black and Minoritised Ethnicity (BME) occupational therapists face lower career progression
opportunities and mentoring is one possible intervention that may offer support. BME persons may have different
expectations and experiences from their mentor, and research exploring their perceptions of mentoring is important.
In Occupational Therapy there is a growing awareness of the need to be true to the values of social justice. The aim
of this research is to learn about BME occupational therapists’ experiences and perceptions of mentoring for career progression.
Methods Four online focus groups involving 19 participants from the UK were held, discussions were facilitated
by researchers using a topic guide. Participants responses were analysed, and codes were brought together to
create Themes including career progression and role models, mentoring relationship, similarity with the mentor and
outcomes from mentoring.
Results The study highlighted that trust is integral to effective mentoring relationships and BME occupational
therapists want mentors who they can trust with their experiences and stories. Compatibility between mentors and
mentees in terms of personality, values, and working styles is crucial for effective mentoring relationships. Providing
opportunities for networking, acknowledging good work and giving permission were all seen as outcomes from good mentoring. The absence of BME role models and ingroup bias were also reported as issues to be addressed.
Conclusion This study explores the perception of mentorship as a mechanism for career advancement in occupational therapists from BME backgrounds, with these results transferable to other health and care professional
groups. We recommend the creation of a mentoring charter for BME healthcare workers in the United Kingdom to ensure that those from BME backgrounds feel supported, mentored, and provided with equitable access to resources, including adequate mentoring and networking opportunitie
Making a difference: Belonging, diversity and inclusion in occupational therapy
Over the past year, COVID-19 has been causing death and adding to grief across the world; during this time, an equally important issue – #blacklivesmatter – has been filling our minds and awakening our hearts to confront misery, enable equity and champion social justice. The events unfolding globally have provided a space for what have been difficult conversations to begin in the occupational therapy profession.
The purpose of this editorial is twofold: First, to share conversations with occupational therapists (OTs) in the United Kingdom, around racism, support for ethnic minorities and career progression; Second, to stimulate debate and dialogue with the wider occupational therapy profession alongside multi-professional groups. Individuals, teams and organisations often discuss conversation regarding equality and diversity, but they are seldom spoken of as race and race-based discrimination or societal equality
Perceptions of Black and Minoritised Ethnic (BME) Occupational Therapists experiences on mentoring
Introduction: Mentorship is perceived as a mechanism to enhance career progression. Within occupational therapy, there is little research to demonstrate the effectiveness of mentoring on career success and no research has explored its relevance for black and minoritised ethnic (BME) occupational therapists. This research explored the experience of mentoring for career progression from a BME perspective using a survey.
Methods: An online survey was conducted with occupational therapists in the United Kingdom who identified as BME. The
primary recruitment method was a convenience sample via a BME network and through its other links. Content analysis and
descriptive statistics were used to analyse and report the data.
Findings: In all, 54 BME occupational therapists completed the survey. Most BME therapists had never requested a BME
mentor, but most wanted a BME mentor. Active allyship was viewed as an important part of mentorship when mentored by
a white therapist.
Conclusion: This research is the first study in occupational therapy to examine the mentoring experiences and needs of BME
therapists. It is a call for action to recognise and reorient the approach and understanding of the structures and experiences of BME mentorship
An exponential lower bound for Individualization-Refinement algorithms for Graph Isomorphism
The individualization-refinement paradigm provides a strong toolbox for
testing isomorphism of two graphs and indeed, the currently fastest
implementations of isomorphism solvers all follow this approach. While these
solvers are fast in practice, from a theoretical point of view, no general
lower bounds concerning the worst case complexity of these tools are known. In
fact, it is an open question whether individualization-refinement algorithms
can achieve upper bounds on the running time similar to the more theoretical
techniques based on a group theoretic approach.
In this work we give a negative answer to this question and construct a
family of graphs on which algorithms based on the individualization-refinement
paradigm require exponential time. Contrary to a previous construction of
Miyazaki, that only applies to a specific implementation within the
individualization-refinement framework, our construction is immune to changing
the cell selector, or adding various heuristic invariants to the algorithm.
Furthermore, our graphs also provide exponential lower bounds in the case when
the -dimensional Weisfeiler-Leman algorithm is used to replace the standard
color refinement operator and the arguments even work when the entire
automorphism group of the inputs is initially provided to the algorithm.Comment: 21 page
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On Birthing Dancing Stars: The Need for Bounded Chaos in Information Interaction
While computers causing chaos is acommon social trope, nearly the entirety of the history of computing is dedicated to generating order. Typical interactive information retrieval tasks ask computers to support the traversal and exploration of large, complex information spaces. The implicit assumption is that they are to support users in simplifying the complexity (i.e. in creating order from chaos). But for some types of task, particularly those that involve the creative application or synthesis of knowledge or the creation of new knowledge, this assumption may be incorrect. It is increasingly evident that perfect order—and the systems we create with it—support highly-structured information tasks well, but provide poor support for less-structured tasks.We need digital information environments that help create a little more chaos from order to spark creative thinking and knowledge creation. This paper argues for the need for information systems that offerwhat we term ‘bounded chaos’, and offers research directions that may support the creation of such interface
Ultra-high energy neutrino scattering
Estimates are made of the ultra-high energy neutrino cross sections based on
an extrapolation to very small Bjorken x of the logarithmic Froissart
dependence in x shown previously to provide an excellent fit to the measured
proton structure function F_2^p(x,Q^2) over a broad range of the virtuality
Q^2. Expressions are obtained for both the neutral current and the charged
current cross sections. Comparison with an extrapolation based on perturbative
QCD shows good agreement for energies where both fit data, but our rates are as
much as a factor of 10 smaller for neutrino energies above 10^9 GeV, with
important implications for experiments searching for extra-galactic neutrinos.Comment: 4 pages, 1 figure, 1 table; Title, abstract and text changed,
conclusions unchanged. Version accepted for publication in Physical Review
Nodular lymphocyte predominant Hodgkin lymphoma behaves as a distinct clinical entity with good outcome: evidence from 14-year followup in the West of Scotland Cancer Network
Clinically and biologically, nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) has much more in common with germinal-center derived B-cell non-Hodgkin lymphoma (NHL) than with classical Hodgkin lymphoma (cHL). Management of NLPHL remains controversial. In a 14-year multicenter series, 69 cases were analyzed, and the median follow-up was 53 months (range 11–165.) B-symptoms were present in only 4.3% of patients, and 81.1% of patients had stage I/II disease. Treatment was with radiotherapy (53.6%), chemotherapy (21.7%), combined modality (17.4%), and observation (7.2%). In all, 10.1% of patients relapsed and 2.9% of patients developed high-grade transformation to DLBCL. All relapses and transformations were salvageable. No patient died of their disease. The 5-year relapse-free survival was 92%, transformation-free survival 98.4%, and overall survival 100%. We conclude that NLPHL behaves as a distinct clinical entity, often presenting at an early stage without risk factors. It has an excellent outcome. It may be possible, in early-stage disease, to reduce the intensity of therapy in NLPHL, to single-modality radiotherapy, without affecting OS
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