Acropolis Educational Resources Repository
Not a member yet
31278 research outputs found
Sort by
EGF and BMPs govern differentiation and patterning in human gastric glands
No full textBackground & Aims
The homeostasis of the gastrointestinal epithelium relies on cell regeneration and differentiation into distinct lineages organised inside glands and crypts. Regeneration depends on WNT/β-Catenin pathway activation, but to understand homeostasis and its dysregulation in disease we need to identify the signalling microenvironment governing cell differentiation. By using gastric glands as a model, we have identified the signals inducing differentiation of surface mucus-, zymogen- and gastric acid- producing cells.
Methods
We generated mucosoid cultures from the human stomach and exposed them to different growth factors to obtain cells with features of differentiated foveolar, chief and parietal cells. We localised the source of the growth factors in the tissue of origin.
Results
We show that EGF is the major fate determinant distinguishing the surface and inner part of human gastric glands. In combination with BMP/NOGGIN signals, EGF controls the differentiation of foveolar cells vs. parietal or chief cells. We also show that EGF is likely to underlie alteration of the gastric mucosa in the pre-cancerous condition atrophic gastritis.
Conclusions
Use of our recently established mucosoid cultures in combination with analysis of the tissue-of-origin provided a robust strategy to understand differentiation and patterning of human tissue and allowed us to draw a new, detailed map of the signalling microenvironment in the human gastric glands
A cultural experience to support mental health in people aged 16-24 during the COVID-19 pandemic compared to a typical museum website: study protocol of an online randomised controlled trial
No full textBackground
Despite the high prevalence of common mental disorders in adolescents and young adults, and their association with poor health and socio-economic outcomes throughout the lifespan, many young people do not seek or receive help for such disorders. There is growing interest in the community sector in supporting mental health in young people; however, there is little by way of experimental research in this area. During the COVID-19 pandemic and lockdown, we designed an online cultural experience to reduce anxiety and depression and support mental health in people aged 16–24.
Methods/design
The O-ACE POP (Online Active Community Engagement Proof of Principle) study is a UK-based online randomised controlled trial of an online cultural experience named Ways of Being, involving human centred narratives and viewpoints, compared with a typical museum website (the Ashmolean Museum). We aim to compare efficacy on affect, symptoms of epression and anxiety, flourishing and loneliness as well as investigating potential mechanisms of action.
Discussion
The COVID-19 pandemic has provided a unique opportunity to design an innovative approach to supporting mental health in young adults. Findings derived from this study will allow us to evaluate the efficacy of this intervention and will inform the design of studies to further refine the resource and test it further.
Trial registration
ClinicalTrials.gov NCT04663594. Registered on 11 December 2020 (submitted in same form 27 November 2020). Protocol v1.0: 27 November 2020. Date recruitment began: 4 December 2020. Recruitment complete (estimate): February 202
Higher-form symmetries of 6d and 5d theories
No full textWe describe general methods for determining higher-form symmetry groups of known 5d and 6d superconformal field theories (SCFTs), and 6d little string theories (LSTs). The 6d theories can be described as supersymmetric gauge theories in 6d which include both ordinary non-abelian 1-form gauge fields and also abelian 2-form gauge fields. Similarly, the 5d theories can also be often described as supersymmetric non-abelian gauge theories in 5d. Naively, the 1-form symmetry of these 6d and 5d theories is captured by those elements of the center of ordinary gauge group which leave the matter content of the gauge theory invariant. However, an interesting subtlety is presented by the fact that some massive BPS excitations, which includes the BPS instantons, are charged under the center of the gauge group, thus resulting in a further reduction of the 1-form symmetry. We use the geometric construction of these theories in M/F-theory to determine the charges of these BPS excitations under the center. We also provide an independent algorithm for the determination of 1-form symmetry for 5d theories that admit a generalized toric construction (i.e. a 5-brane web construction). The 2-form symmetry group of 6d theories, on the other hand, is captured by those elements of the center of the abelian 2-form gauge group that leave all the massive BPS string excitations invariant, which is much more straightforward to compute as it is encoded in the Green-Schwarz coupling associated to the 6d theory
Indicative conditionals and epistemic luminosity
No full textKevin Dorst has recently pointed out an apparently puzzling consequence of denying epistemic luminosity: given some natural-sounding bridging principles between knowledge, credence, and indicative conditionals, the denial of epistemic luminosity licenses the knowledge and assertability of abominable-sounding conditionals of the form ┌If I don’t know that ϕ, then ϕ┐. We provide a general and systematic examination of this datum by testing Dorst’s claim against various semantics for the indicative conditional in the setting of epistemic logic. Our conclusion is that, regardless of whether knowledge is luminous, the knowability of these conditionals is highly sensitive to the correct semantic analysis of the indicative conditional. Moreover, standard pragmatic resources can explain away the infelicity of such assertions. As it stands, the datum does not tell against epistemic non-luminosity
On the maximum number of integer colourings with forbidden monochromatic sums
No full textLet
f
(
n
,
r
)
denote the maximum number of colourings of
A
⊆
{
1
,
…
,
n
}
with
r
colours such that each colour class is sum-free. Here, a sum is a subset
{
x
,
y
,
z
}
such that
x
+
y
=
z
. We show that
f
(
n
,
2
)
=
2
⌈
n
/
2
⌉
, and describe the extremal subsets. Further, using linear optimisation, we asymptotically determine the logarithm of
f
(
n
,
r
)
for
r
⩽
5
. Similar results were obtained by Hán and Jiménez in the setting of finite abelian groups
Development of a visual, patient-reported tool for assessing the multi-dimensional burden of endometriosis
No full textOBJECTIVE: Inadequate communication about endometriosis symptom burden between women and healthcare providers is a barrier for optimal treatment. This study describes the development of the EndoWheel, a patient-reported assessment tool that visualizes the multi-dimensional burden of endometriosis to facilitate patient-provider communication. METHODS: Assessment questions for the tool were developed using an iterative Delphi consensus process. A consensus phase included additional practitioners and specialists to broaden perspectives and select revised statements. Semi-structured qualitative interviews were conducted with 13 women with endometriosis to assess the scoring and content of the measures. RESULTS: Symptoms included in the tool were pelvic pain, vaginal bleeding, bowel/bladder symptoms, energy levels, fertility, impact on activities, emotional and sexual well-being, and self-perceived global health. Additional life impact areas included relationships, social and occupational activity, and self-perception. The 13 interviewees completed the tool in approximately 5-6 minutes (range 4.0-7.5 minutes). Most participants (92%) perceived that the tool would enable better patient-provider communication, including addressing symptoms and areas of impact not normally discussed during office visits. CONCLUSION: Similar to visual circular tools used in burden assessment of other chronic diseases, the tool may facilitate improved patient dialogue with providers around endometriosis treatment goals and options
Ethically utilising COVID-19 host-genomic data
No full textGenetic variants that influence susceptibility to COVID-19 have recently been identified. In this manuscript, we identify and discuss some of the ethical and practical issues raised by these studies. We first outline the ethical case for providing COVID-19 susceptibility testing to healthcare workers, as well as highlighting risks associated with privacy and discrimination. We then argue that the existence of genetically susceptible individuals has implications for the ethical conduct of COVID-19 human challenge trials. Finally, we discuss the ethical issues that could arise from other COVID-19 host–genome interactions, including the prospect of personalized vaccines
The public-private partnership (PPP) model in the development of e-commerce and digital skills training in rural China
No full textThe rise of e-commerce platforms in developing countries is creating new business opportunities in rural economies, which drives governments to cooperate with private sector industries on the development of a good ICT infrastructure.
This paper features a case study from central China to demonstrate how the private sector is collaborating with the government to deliver skills training workshops for rural residents and thereby facilitate e-commerce in developing regions.
The collaboration between the public and private sectors represents a new strategy to facilitate a digital economy that incorporates marginalised communities in developing areas. However, findings from the fieldwork show that digital skills training for rural participants requires the provision of supporting resources, such as affordable e-commerce consultancy services and accessible technical assistance
Η Ακρόπολη κατά την Αρχαϊκή Εποχή (700-480 π.Χ.) (only in greek)
No full textΣχέδιο προετοιμασίας ανεξάρτητης επίσκεψης στην Αρχαϊκή Συλλογή του Μουσείου Ακρόπολη
GAMA/DEVILS: constraining the cosmic star formation history from improved measurements of the 0.3-2.2 mu m extragalactic background light
No full textWe present a revised measurement of the optical extragalactic background light (EBL), based on the contribution of resolved galaxies to the integrated galaxy light (IGL). The cosmic optical background radiation (COB), encodes the light generated by star formation, and provides a wealth of information about the cosmic star formation history (CSFH). We combine wide and deep galaxy number counts from the Galaxy And Mass Assembly survey (GAMA) and Deep Extragalactic VIsible Legacy Survey (DEVILS), along with the Hubble Space Telescope (HST) archive and other deep survey data sets, in nine multiwavelength filters to measure the COB in the range from 0.35 μm to 2.2 μm. We derive the luminosity density in each band independently and show good agreement with recent and complementary estimates of the optical-EBL from very high-energy (VHE) experiments. Our error analysis suggests that the IGL and γ-ray measurements are now fully consistent to within ∼10 per cent, suggesting little need for any additional source of diffuse light beyond the known galaxy population. We use our revised IGL measurements to constrain the CSFH, and place amplitude constraints on a number of recent estimates. As a consistency check, we can now demonstrate convincingly, that the CSFH, stellar mass growth, and the optical-EBL provide a fully consistent picture of galaxy evolution. We conclude that the peak of star formation rate lies in the range 0.066–0.076 M⊙ yr−1 Mpc−3 at a lookback time of 9.1 to 10.9 Gyr