527 research outputs found
Imaging Granulomatous Lesions with Optical Coherence Tomography
www.karger.com/cde This is an Open Access article licensed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License (www.karger.com/OA-license), applicable to the online version of the article only. Distribution for non-commercial purposes only
Optimal transport on supply-demand networks
Previously, transport networks are usually treated as homogeneous networks,
that is, every node has the same function, simultaneously providing and
requiring resources. However, some real networks, such as power grid and supply
chain networks, show a far different scenario in which the nodes are classified
into two categories: the supply nodes provide some kinds of services, while the
demand nodes require them. In this paper, we propose a general transport model
for those supply-demand networks, associated with a criterion to quantify their
transport capacities. In a supply-demand network with heterogenous degree
distribution, its transport capacity strongly depends on the locations of
supply nodes. We therefore design a simulated annealing algorithm to find the
optimal configuration of supply nodes, which remarkably enhances the transport
capacity, and outperforms the degree target algorithm, the betweenness target
algorithm, and the greedy method. This work provides a start point for
systematically analyzing and optimizing transport dynamics on supply-demand
networks.Comment: 5 pages, 1 table and 4 figure
Continuous extremal optimization for Lennard-Jones Clusters
In this paper, we explore a general-purpose heuristic algorithm for finding
high-quality solutions to continuous optimization problems. The method, called
continuous extremal optimization(CEO), can be considered as an extension of
extremal optimization(EO) and is consisted of two components, one is with
responsibility for global searching and the other is with responsibility for
local searching. With only one adjustable parameter, the CEO's performance
proves competitive with more elaborate stochastic optimization procedures. We
demonstrate it on a well known continuous optimization problem: the
Lennerd-Jones clusters optimization problem.Comment: 5 pages and 3 figure
False-Name Manipulation in Weighted Voting Games is Hard for Probabilistic Polynomial Time
False-name manipulation refers to the question of whether a player in a
weighted voting game can increase her power by splitting into several players
and distributing her weight among these false identities. Analogously to this
splitting problem, the beneficial merging problem asks whether a coalition of
players can increase their power in a weighted voting game by merging their
weights. Aziz et al. [ABEP11] analyze the problem of whether merging or
splitting players in weighted voting games is beneficial in terms of the
Shapley-Shubik and the normalized Banzhaf index, and so do Rey and Rothe [RR10]
for the probabilistic Banzhaf index. All these results provide merely
NP-hardness lower bounds for these problems, leaving the question about their
exact complexity open. For the Shapley--Shubik and the probabilistic Banzhaf
index, we raise these lower bounds to hardness for PP, "probabilistic
polynomial time", and provide matching upper bounds for beneficial merging and,
whenever the number of false identities is fixed, also for beneficial
splitting, thus resolving previous conjectures in the affirmative. It follows
from our results that beneficial merging and splitting for these two power
indices cannot be solved in NP, unless the polynomial hierarchy collapses,
which is considered highly unlikely
Quality index approach for analysis of urban green infrastructure in Himalayan cities
In fast urbanizing cities, fragmentation of urban green infrastructure (UGI) commonly arises due to lack of efficient planning to maintain the quantity and improve their quality. As ecological processes and landscape patterns are closely intertwined, it is a prerequisite to investigate landscape structure when aiming at better provision of ecosystem services. This study integrates remote sensing, geographic information system, combination of landscape metrics, and multi-variated statistics to delineate structural attributes influencing UGI Quality (UGIQ). We exemplify our methodology in three capital cities of Indian Himalayan states at administrative ward level. The UGIQ is derived by comparing landscape characters defined by nine metrics denoting area, shape, and aggregation attributes. By employing principal component analysis (PCA) and multi-collinearity diagnosis, a set of quality defining metrics are obtained for each city. Further, to gain insightful spatial basis for improving connectivity, Morphological Spatial Pattern Analysis (MSPA) is used to visualize and classify patches into seven morphological classes. Landscape characterization highlights a pattern of low-quality wards having a limited number and area of UGI patches in urban centers, and high-quality wards with complex and aggregated patches towards fringes. PCA identifies the positive influence of area (LPI, AREA_MN) and shape (LSI, FRAC_AM, CONTIG) metrics and negative influence of patch distance (ENN_MN) and fragmentation (PD) on UGIQ in different combinations across the cities. Higher shares of morphological core and edge classes are recognized for overall UGIQ improvement. The results provide quantitative measures to develop integrated spatial planning strategies
Soil tillage and windbreak efects on millet and cowpea: I. Wind speed, evaporation, and wind erosion
Deforestation, overgrazing, and declining soil regeneration periods
have resulted in increased wind erosion problems in dry areas of th;
West African Sahel, but little is known about the bio-physical factors
involved. This research was conducted to determine the effects of
ridging and four different windbreak spacings on wind erosion, potential
evaporation, and soil water reserves. A field trial was conducted
from 1985 to 1987 on 12 ha of a Psammentic Paleustalf in
Southern Niger. Millet, Pennisetum glaucum (L.), and cowpea, Vigmi
unguiculata (L.) Walp., were seeded in strips on flat and ridged soil.
Windbreaks of savannah vegetation were spaced at 6, 20, 40, and 91)
m. The effects of ridging on wind speed, evaporation, and wind erosion
were small and mostly non-significant. However, average wind speed at 0.3 m above ground in the center of cowpea and millet strips
was significantly reduced from 2.8 to 2.1 m s"1 as windbreak distances
narrowed from 90 to 6 m
Soil tillage and windbreak effects on millet and cowpea: II. Dry matter and grain yield
In the West Africa Sahel, sand storms occuring early in the growing season may severely damage emerging crops. This study was conducted to determine
the influence of ridges and windbreaks on growth, water use and grain yield of millet, pennisetum glaucum (L.), and cowpea, Vigna unguiculata (L.) Walp
Діагностична значимість полярізаційно-оптичних властивостей рогівки ока при патології внутрішньоочного тиску
Незважаючи на прогрес в методах лікування і діагностики, глаукома останніми роками
стала головною причиною невиліковної сліпоти в розвинених країнах світу. За даними ВООЗ
більше 67 млн. чоловік в світі хворіють на глаукому і до 2030 року ця цифра повинна
подвоїтися. Підвищення внутрішньоочного тиску (ВОТ) є одною з основних клінічних ознак
глаукомного процесу, реєстрація якого лежить в основі діагностики і вибору методу
адекватного лікування. Практично всі існуючи в теперішній час методи виміру ВОТ
засновані на різних впливах на око (вантажами, плунжерами або струменем повітря). Як
було встановлено, результати таких вимірів ВОТ суттєво залежать від біомеханічних
параметрів рогівки або ока
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Risk Factors for Cervical Precancer and Cancer in HIV-Infected, HPV-Positive Rwandan Women
Background: Although cervical cancer is an AIDS-defining condition, infection with human immunodeficiency virus (HIV) may only modestly increase the risk of cervical cancer. There is a paucity of information regarding factors that influence the natural history of human papillomavirus (HPV) in HIV-infected women. We examined factors associated with cervical intraepithelial neoplasia grade 3 or cancer (CIN3+) in Rwandan women infected with both HIV and HPV (HIV+/HPV+).Methods: In 2005, 710 HIV+ Rwandan women ≥25 years enrolled in an observational cohort study; 476 (67%) tested HPV+. Each woman provided sociodemographic data, CD4 count, a cervical cytology specimen and cervicovaginal lavage (CVL), which was tested for >40 HPV genotypes by MY09/MY11 PCR assay. Logistic regression models calculated odds ratios (OR) and 95% confidence intervals (CI) of associations of potential risk factors for CIN3+ among HIV+/HPV+ women.Results: Of the 476 HIV+/HPV+ women 42 (8.8%) were diagnosed with CIN3+. Factors associated with CIN3+ included ≥7 (vs. 0-2) pregnancies, malarial infection in the previous six months (vs. never), and ≥7 (vs. 0-2) lifetime sexual partners. Compared to women infected by non-HPV16 carcinogenic HPV genotypes, HPV16 infection was positively associated and non-carcinogenic HPV infection was inversely associated with CIN3+. CD4 count was significantly associated with CIN3+ only in analyses of women with non-HPV16 carcinogenic HPV (OR = 0.62 per 100 cells/mm3, CI = 0.40-0.97).Conclusions: In this HIV+/HPV+ population, lower CD4 was significantly associated with CIN3+ only in women infected with carcinogenic non-HPV16. We found a trend for higher risk of CIN3+ in HIV+ women reporting recent malarial infection; this association should be investigated in a larger group of HIV+/HPV+ women.</p
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