896 research outputs found
Heavy-ion irradiations of Fe and Fe–Cr model alloys Part 2: Damage evolution in thin-foils at higher doses
Assessing carbon dioxide storage integrity of an extensive saline aquifer formation: East Irish Sea Basin, UK
Accurately determining the contemporary pore pressure and in situ stress conditions is critical to the safe planning and development of subsurface operations such as CO2 storage. According to the UK storage capacity atlas, CO2STORED (Bentham et al. 2014), the East Irish Sea Basin (EISB) has a significant storage capacity of nearly 4 Gt (P50) within saline aquifer parts of the Triassic-aged Ormskirk Sandstone Formation (OSF). The OSF is present over a significant part of the EISB, and where buried deeply enough to be considered for CO2 storage is overlain by the Mercia Mudstone Group (MMG), a thick sequence comprising up to 3200 m of interbedded mudstones, siltstones and evaporites. As a result of Tertiary inversion, the Jurassic and younger succession is absent over most of the basin, and so the MMG represents the vast majority of the overburden succession. The presence of numerous gas accumulations, including the Morecambe South Gas Field with its ~400 m gas column, is testament to the sealing capacity of the MMG. Where halite formations within the MMG directly overly the OSF, the sealing capacity of the MMG is significantly increased
Classical stability of U(1)_A domain walls in dense matter QCD
It was recently shown that there exists metastable U(1)_A domain wall
configurations in high-density QCD (\mu >> 1 GeV). In the following we will
assess the stability of such non-trivial field configurations at intermediate
densities (\mu < 1 GeV). The existence of such configurations at intermediate
densities could have interesting consequences for the physics of neutron stars
with high core density.Comment: 13 pages, 2 Postscript figures, typos correcte
A 3D Fully Convolutional Neural Network With Top-Down Attention-Guided Refinement for Accurate and Robust Automatic Segmentation of Amygdala and Its Subnuclei
Recent advances in deep learning have improved the segmentation accuracy of subcortical brain structures, which would be useful in neuroimaging studies of many neurological disorders. However, most existing deep learning based approaches in neuroimaging do not investigate the specific difficulties that exist in segmenting extremely small but important brain regions such as the subnuclei of the amygdala. To tackle this challenging task, we developed a dual-branch dilated residual 3D fully convolutional network with parallel convolutions to extract more global context and alleviate the class imbalance issue by maintaining a small receptive field that is just the size of the regions of interest (ROIs). We also conduct multi-scale feature fusion in both parallel and series to compensate the potential information loss during convolutions, which has been shown to be important for small objects. The serial feature fusion enabled by residual connections is further enhanced by a proposed top-down attention-guided refinement unit, where the high-resolution low-level spatial details are selectively integrated to complement the high-level but coarse semantic information, enriching the final feature representations. As a result, the segmentations resulting from our method are more accurate both volumetrically and morphologically, compared with other deep learning based approaches. To the best of our knowledge, this work is the first deep learning-based approach that targets the subregions of the amygdala. We also demonstrated the feasibility of using a cycle-consistent generative adversarial network (CycleGAN) to harmonize multi-site MRI data, and show that our method generalizes well to challenging traumatic brain injury (TBI) datasets collected from multiple centers. This appears to be a promising strategy for image segmentation for multiple site studies and increased morphological variability from significant brain pathology
The role of knowledge and research in two case studies on cross‐border marine spatial planning in the southern North Sea
Quantitative analysis of breast cancer tissue composition and associations with tumor subtype
The tumor microenvironment is an important determinant of breast cancer progression, but standard methods for describing the tumor microenvironment are lacking. Measures of microenvironment composition such as stromal area and immune infiltrate are labor-intensive and few large studies have systematically collected this data. However, digital histologic approaches are becoming more widely available, allowing high-throughput, quantitative estimation. We applied such methods to tissue microarrays of tumors from 1687 women (mean 4 cores per case) in the Carolina Breast Cancer Study Phase 3. Tumor composition was quantified as percentage of epithelium, stroma, adipose, and lymphocytic infiltrate (with the latter as presence/absence using a ≥1% cutoff). Composition proportions and presence/absence were evaluated in association with clinical and molecular features of breast cancer (intrinsic subtype and RNA-based risk of recurrence [ROR] scores) using multivariable linear and logistic regression. Lower stromal content was associated with aggressive tumor phenotypes, including triple-negative (31.1% vs. 41.6% in HR+/HER2-; RFD [95% CI]: −10.5%, [-13.1, −7.9]), Basal-like subtypes (29.0% vs. 44.0% in Luminal A; RFD [95% CI]: −14.9%, [-17.8, −12.0]), and high RNA-based PAM50 ROR scores (27.6% vs. 48.1% in ROR low; RFD [95% CI]: −20.5%, [24.3, 16.7]), after adjusting for age and race. HER2+ tumors also had lower stromal content, particularly among RNA-based HER2-enriched (35.2% vs. 44.0% in Luminal A; RFD [95% CI]: −8.8%, [-13.8, −3.8]). Similar associations were observed between immune infiltrate and tumor phenotypes. Quantitative digital image analysis of the breast cancer microenvironment showed significant associations with demographic characteristics and biological indicators of aggressive behavior
Vascular density of histologically benign breast tissue from women with breast cancer: associations with tissue composition and tumor characteristics
In breast tumors, it is well established that intratumoral angiogenesis is crucial for malignant progression, but little is known about the vascular characteristics of extratumoral, cancer-adjacent breast. Genome-wide transcriptional data suggest that extratumoral microenvironments may influence breast cancer phenotypes; thus, histologic features of cancer-adjacent tissue may also have clinical implications. To this end, we developed a digital algorithm to quantitate vascular density in approximately 300 histologically benign tissue specimens from breast cancer patients enrolled in the UNC Normal Breast Study (NBS). Specimens were stained for CD31, and vascular content was compared to demographic variables, tissue composition metrics, and tumor molecular features. We observed that the vascular density of cancer-adjacent breast was significantly higher in older and obese women, and was strongly associated with breast adipose tissue content. Consistent with observations that older and heavier women experience higher frequencies of ER+ disease, higher extratumoral vessel density was also significantly associated with positive prognostic tumor features such as lower stage, negative nodal status, and smaller size (<2 cm). These results reveal biological relationships between extratumoral vascular content and body size, breast tissue composition, and tumor characteristics, and suggest biological plausibility for the relationship between weight gain (and corresponding breast tissue changes) and breast cancer progression
Fixed point results for generalized cyclic contraction mappings in partial metric spaces
Rus (Approx. Convexity 3:171–178, 2005) introduced the concept of cyclic contraction
mapping. P˘acurar and Rus (Nonlinear Anal. 72:1181–1187, 2010) proved some fixed
point results for cyclic φ-contraction mappings on a metric space. Karapinar (Appl. Math.
Lett. 24:822–825, 2011) obtained a unique fixed point of cyclic weak φ- contraction mappings
and studied well-posedness problem for such mappings. On the other hand, Matthews
(Ann. New York Acad. Sci. 728:183–197, 1994) introduced the concept of a partial metric
as a part of the study of denotational semantics of dataflow networks. He gave a modified
version of the Banach contraction principle, more suitable in this context. In this paper, we
initiate the study of fixed points of generalized cyclic contraction in the framework of partial
metric spaces. We also present some examples to validate our results.S. Romaguera acknowledges the support of the Ministry of Science and Innovation of Spain, grant MTM2009-12872-C02-01.Abbas, M.; Nazir, T.; Romaguera Bonilla, S. (2012). Fixed point results for generalized cyclic contraction mappings in partial metric spaces. Revista- Real Academia de Ciencias Exactas Fisicas Y Naturales Serie a Matematicas. 106(2):287-297. https://doi.org/10.1007/s13398-011-0051-5S2872971062Abdeljawad T., Karapinar E., Tas K.: Existence and uniqueness of a common fixed point on partial metric spaces. Appl. Math. Lett. 24(11), 1894–1899 (2011). doi: 10.1016/j.aml.2011.5.014Altun, I., Erduran A.: Fixed point theorems for monotone mappings on partial metric spaces. Fixed Point Theory Appl. article ID 508730 (2011). doi: 10.1155/2011/508730Altun I., Sadarangani K.: Corrigendum to “Generalized contractions on partial metric spaces” [Topology Appl. 157 (2010), 2778–2785]. Topol. Appl. 158, 1738–1740 (2011)Altun I., Simsek H.: Some fixed point theorems on dualistic partial metric spaces. J. Adv. Math. Stud. 1, 1–8 (2008)Altun I., Sola F., Simsek H.: Generalized contractions on partial metric spaces. Topol. Appl. 157, 2778–2785 (2010)Aydi, H.: Some fixed point results in ordered partial metric spaces. arxiv:1103.3680v1 [math.GN](2011)Boyd D.W., Wong J.S.W.: On nonlinear contractions. Proc. Am. Math. Soc. 20, 458–464 (1969)Bukatin M., Kopperman R., Matthews S., Pajoohesh H.: Partial metric spaces. Am. Math. Monthly 116, 708–718 (2009)Bukatin M.A., Shorina S.Yu. et al.: Partial metrics and co-continuous valuations. In: Nivat, M. (eds) Foundations of software science and computation structure Lecture notes in computer science vol 1378., pp. 125–139. Springer, Berlin (1998)Derafshpour M., Rezapour S., Shahzad N.: On the existence of best proximity points of cyclic contractions. Adv. Dyn. Syst. Appl. 6, 33–40 (2011)Heckmann R.: Approximation of metric spaces by partial metric spaces. Appl. Cat. Struct. 7, 71–83 (1999)Karapinar E.: Fixed point theory for cyclic weak -contraction. App. Math. Lett. 24, 822–825 (2011)Karapinar, E.: Generalizations of Caristi Kirk’s theorem on partial metric spaces. Fixed Point Theory Appl. 2011,4 (2011). doi: 10.1186/1687-1812-2011-4Karapinar E.: Weak -contraction on partial metric spaces and existence of fixed points in partially ordered sets. Math. Aeterna. 1(4), 237–244 (2011)Karapinar E., Erhan I.M.: Fixed point theorems for operators on partial metric spaces. Appl. Math. Lett. 24, 1894–1899 (2011)Karpagam S., Agrawal S.: Best proximity point theorems for cyclic orbital Meir–Keeler contraction maps. Nonlinear Anal. 74, 1040–1046 (2011)Kirk W.A., Srinavasan P.S., Veeramani P.: Fixed points for mapping satisfying cylical contractive conditions. Fixed Point Theory. 4, 79–89 (2003)Kosuru, G.S.R., Veeramani, P.: Cyclic contractions and best proximity pair theorems). arXiv:1012.1434v2 [math.FA] 29 May (2011)Matthews S.G.: Partial metric topology. in: Proc. 8th Summer Conference on General Topology and Applications. Ann. New York Acad. Sci. 728, 183–197 (1994)Neammanee K., Kaewkhao A.: Fixed points and best proximity points for multi-valued mapping satisfying cyclical condition. Int. J. Math. Sci. Appl. 1, 9 (2011)Oltra S., Valero O.: Banach’s fixed theorem for partial metric spaces. Rend. Istit. Mat. Univ. Trieste. 36, 17–26 (2004)Păcurar M., Rus I.A.: Fixed point theory for cyclic -contractions. Nonlinear Anal. 72, 1181–1187 (2010)Petric M.A.: Best proximity point theorems for weak cyclic Kannan contractions. Filomat. 25, 145–154 (2011)Romaguera, S.: A Kirk type characterization of completeness for partial metric spaces. Fixed Point Theory Appl. (2010, article ID 493298, 6 pages).Romaguera, S.: Fixed point theorems for generalized contractions on partial metric spaces. Topol. Appl. (2011). doi: 10.1016/j.topol.2011.08.026Romaguera S., Valero O.: A quantitative computational model for complete partial metric spaces via formal balls. Math. Struct. Comput. Sci. 19, 541–563 (2009)Rus, I.A.: Cyclic representations and fixed points. Annals of the Tiberiu Popoviciu Seminar of Functional equations. Approx. Convexity 3, 171–178 (2005), ISSN 1584-4536Schellekens M.P.: The correspondence between partial metrics and semivaluations. Theoret. Comput. Sci. 315, 135–149 (2004)Valero O.: On Banach fixed point theorems for partial metric spaces. Appl. Gen. Top. 6, 229–240 (2005)Waszkiewicz P.: Quantitative continuous domains. Appl. Cat. Struct. 11, 41–67 (2003
The abolition of the General Teaching Council for England and the future of teacher discipline
With the abolition of the General Teaching Council for England in the 2011 Education Act, this article considers the future of teacher discipline in England. It provides a critique of the changes to the regulation of teacher misconduct and incompetence that draws on a Foucauldian framework, especially concerning the issue of public displays of discipline and the concomitant movement to more hidden forms. In addition, the external context of accountability that accompanies the reforms to teacher discipline are considered including the perfection of the panoptic metaphor presented by the changes to Ofsted practices such as the introduction of zero-notice inspections. The article concludes that the reforms will further move teachers from being occupational professionals to being organisational professionals marking them apart from comparable professions in medicine and law
- …