534 research outputs found
Multiple Schramm-Loewner Evolutions and Statistical Mechanics Martingales
A statistical mechanics argument relating partition functions to martingales
is used to get a condition under which random geometric processes can describe
interfaces in 2d statistical mechanics at criticality. Requiring multiple SLEs
to satisfy this condition leads to some natural processes, which we study in
this note. We give examples of such multiple SLEs and discuss how a choice of
conformal block is related to geometric configuration of the interfaces and
what is the physical meaning of mixed conformal blocks. We illustrate the
general ideas on concrete computations, with applications to percolation and
the Ising model.Comment: 40 pages, 6 figures. V2: well, it looks better with the addresse
Quality in Requirements Engineering (RE) Explained Using Distributed Cognition: A Case of Open Source Development
Requirements have been the culprits for budget overruns and failures in software development projects. Fixing the requirements in the early stages of a project can dramatically reduce recurring costs. Past research has focused on linear sequential requirements activities as a means to fix the requirement problems. This line of thinking has led researchers to overlook the possible solutions to requirement problems in social, cognitive, and organizational factors. We probe the success of open source software development and its implications for the linear approach to requirements activity. Despite a wide scale distribution of requirements knowledge among people and artifacts, open source projects have been able to manage and evolve requirements in an organic way leading to high quality outcomes. Even though such efforts include little emphasis on explicit quality in RE practices, these projects often come up with software that meets high quality requirements. In order to understand this anomaly in open source software development, we apply the theory of distributed cognition to understand how social, structural, and temporal dimension impacts the quality of the requirements
Diverse in Local, Overlapping in Official Medical Botany: Critical Analysis of Medicinal Plant Records from the Historic Regions of Livonia and Courland in Northeast Europe, 1829â1895
Works on historical ethnobotany can help shed light on past plant uses and humankindâs relationships with the environment. We analyzed medicinal plant uses from the historical regions of Livonia and Courland in Northeast Europe based on three studies published within the 19th century by medical doctors researching local ethnomedicine. The sources were manually searched, and information extracted and entered into a database. In total, there were 603 detailed reports of medicinal plant use, which refer to 219 taxa belonging to 69 families and one unidentified local taxon. Dominant families were Asteraceae (14%), Solanaceae (7%), Rosaceae (6%), and Apiaceae (5%). The majority of use reports were attributed to the treatment of four disease categories: digestive (24%), skin (22%), respiratory (11%), and general (11%). The small overlapping portion (14 taxa mentioned by all three authors and another 27 taxa named by two authors) contained a high proportion of taxa (46%) mentioned in Dioscorides, which were widespread during that period in scholarly practice. Despite the shared flora, geographical vicinity, and culturally similar backgrounds, the medicinal use of plants in historical Courland and Livonia showed high biocultural diversity and reliance on wild taxa. We encourage researchers to study and re-evaluate the historical ethnobotanical literature and provide some suggestions on how to do this effectively
Improving a real-time object detector with compact temporal information
Neural networks designed for real-time object detectionhave recently improved significantly, but in practice, look-ing at only a single RGB image at the time may not be ideal.For example, when detecting objects in videos, a foregrounddetection algorithm can be used to obtain compact temporaldata, which can be fed into a neural network alongside RGBimages. We propose an approach for doing this, based onan existing object detector, that re-uses pretrained weightsfor the processing of RGB images. The neural network wastested on the VIRAT dataset with annotations for object de-tection, a problem this approach is well suited for. The ac-curacy was found to improve significantly (up to 66%), witha roughly 40% increase in computational time
Virasoro Module Structure of Local Martingales of SLE Variants
Martingales often play an important role in computations with Schramm-Loewner
evolutions (SLEs). The purpose of this article is to provide a straightforward
approach to the Virasoro module structure of the space of local martingales for
variants of SLEs. In the case of ordinary chordal SLE, it has been shown in
Bauer & Bernard: Phys.Lett.B 557 that polynomial local martingales form a
Virasoro module. We will show for more general variants that the module of
local martingales has a natural submodule M that has the same interpretation as
the module of polynomial local martingales of chordal SLE, but it is in many
cases easy to find more local martingales than that. We discuss the
surprisingly rich structure of the Virasoro module M and construction of the
``SLE state'' or ``martingale generating function'' by Coulomb gas formalism.
In addition, Coulomb gas or Feigin-Fuchs integrals will be shown to
transparently produce candidates for multiple SLE pure geometries.Comment: 48 pages, 3 figures. v4: Completely reorganized, with new results,
erroneous corollary 4 (in v3) correcte
Active wild food practices among culturally diverse groups in the 21st century across latgale, Latvia
Local ecological knowledge (LEK), including but not limited to the use of wild food plants, plays a large role in sustainable natural resource management schemes, primarily due to the synergy between plants and people. There are calls for the study of LEK in culturally diverse areas due to a loss of knowledge, the active practice of utilizing wild plants in various parts of the world, and a decline in biodiversity. An ethnobotanical study in a border region of Latvia, characterised by diverse natural landscapes and people with deep spiritual attachments to nature, provided an opportunity for such insight, as well as the context to analyse wild food plant usages among different sociocultural groups, allowing us to explore the differences among these groups. Semi-structured interviews were carried out as part of a wider ethnobotanical field study to obtain information about wild food plants and their uses. The list of wild food plant uses, derived from 72 interviews, revealed a high level of homogenisation (in regards to knowledge) among the study groups, and that many local uses of wild food plants are still actively practiced. People did not gather plants as a recreational activity but rather as a source of diet diversification. The results provide evidence of the importance of safeguarding ecological and cultural diversity due to high local community dependency on natural resources
Weisskopf-Wigner model for wave packet excitation
We consider a laser induced molecular excitation process as a decay of a
single energy state into a continuum. The analytic results based on
Weisskopf-Wigner approach and perturbation calculations are compared with
numerical wave packet results. We find that the decay model describes the
excitation process well within the expected parameter region.Comment: 14 pages, Latex2.09, 9 Postscript figures embedded using psfig, see
also http://www.physics.helsinki.fi/~kasuomin
The Global Retinoblastoma Outcome Study : a prospective, cluster-based analysis of 4064 patients from 149 countries
Background Retinoblastoma is the most common intraocular cancer worldwide. There is some evidence to suggest that major differences exist in treatment outcomes for children with retinoblastoma from different regions, but these differences have not been assessed on a global scale. We aimed to report 3-year outcomes for children with retinoblastoma globally and to investigate factors associated with survival. Methods We did a prospective cluster-based analysis of treatment-naive patients with retinoblastoma who were diagnosed between Jan 1,2017, and Dec 31,2017, then treated and followed up for 3 years. Patients were recruited from 260 specialised treatment centres worldwide. Data were obtained from participating centres on primary and additional treatments, duration of follow-up, metastasis, eye globe salvage, and survival outcome. We analysed time to death and time to enucleation with Cox regression models. Findings The cohort included 4064 children from 149 countries. The median age at diagnosis was 23.2 months (IQR 11.0-36.5). Extraocular tumour spread (cT4 of the cTNMH classification) at diagnosis was reported in five (0.8%) of 636 children from high-income countries, 55 (5.4%) of 1027 children from upper-middle-income countries, 342 (19. 7%) of 1738 children from lower-middle-income countries, and 196 (42.9%) of 457 children from low-income countries. Enudeation surgery was available for all children and intravenous chemotherapy was available for 4014 (98.8%) of 4064 children. The 3-year survival rate was 99.5% (95% CI 98.8-100.0) for children from high-income countries, 91.2% (89.5-93.0) for children from upper-middle-income countries, 80.3% (78.3-82.3) for children from lower-middle-income countries, and 57.3% (524-63-0) for children from low-income countries. On analysis, independent factors for worse survival were residence in low-income countries compared to high-income countries (hazard ratio 16.67; 95% CI 4.76-50.00), cT4 advanced tumour compared to cT1 (8.98; 4.44-18.18), and older age at diagnosis in children up to 3 years (1.38 per year; 1.23-1.56). For children aged 3-7 years, the mortality risk decreased slightly (p=0.0104 for the change in slope). Interpretation This study, estimated to include approximately half of all new retinoblastoma cases worldwide in 2017, shows profound inequity in survival of children depending on the national income level of their country of residence. In high-income countries, death from retinoblastoma is rare, whereas in low-income countries estimated 3-year survival is just over 50%. Although essential treatments are available in nearly all countries, early diagnosis and treatment in low-income countries are key to improving survival outcomes. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd.Peer reviewe
A Swendsen-Wang update algorithm for the Symanzik improved sigma model
We study a generalization of Swendsen-Wang algorithm suited for Potts models
with next-next-neighborhood interactions. Using the embedding technique
proposed by Wolff we test it on the Symanzik improved bidimensional non-linear
model. For some long range observables we find a little slowing down
exponent () that we interpret as an effect of the partial
frustration of the induced spin model.Comment: Self extracting archive fil
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