scholarly journals Mitigating DDoS using weight‐based geographical clustering

Author(s):  
Madeleine Kongshavn ◽  
Hårek Haugerud ◽  
Anis Yazidi ◽  
Torleiv Maseng ◽  
Hugo Hammer
Author(s):  
B. M. Minchew ◽  
C. R. Meyer

Glacier surges are quasi-periodic episodes of rapid ice flow that arise from increases in slip rate at the ice–bed interface. The mechanisms that trigger and sustain surges are not well understood. Here, we develop a new model of incipient surge motion for glaciers underlain by sediments to explore how surges may arise from slip instabilities within a thin layer of saturated, deforming subglacial till. Our model represents the evolution of internal friction, porosity and pore water pressure within the till as functions of the rate and history of shear deformation, and couples the till mechanics to a simple ice-flow model. Changes in pore water pressure govern incipient surge motion, with less permeable till facilitating surging because dilation-driven reductions in pore water pressure slow the rate at which till tends towards a new steady state, thereby allowing time for the glacier to thin dynamically. The reduction of overburden (and thus effective) pressure at the bed caused by dynamic thinning of the glacier sustains surge acceleration in our model. The need for changes in both the hydromechanical properties of the till and the thickness of the glacier creates restrictive conditions for surge motion that are consistent with the rarity of surge-type glaciers and their geographical clustering.


1995 ◽  
Vol 33 (11) ◽  
pp. 2999-3003 ◽  
Author(s):  
I L de Rivera ◽  
L Amador ◽  
S Mourra ◽  
Z Li ◽  
S Rasheed

2005 ◽  
Vol 10 (9) ◽  
pp. 5-6 ◽  
Author(s):  
D Akbulut ◽  
J Dennis ◽  
M Gent ◽  
K A Grant ◽  
V Hope ◽  
...  

Wound infections due to Clostridium botulinum were not recognised in the UK and Republic of Ireland before 2000. C. botulinum produces a potent neurotoxin which can cause paralysis and death. In 2000 and 2001, ten cases were clinically recognised, with a further 23 in 2002, 15 in 2003 and 40 cases in 2004. All cases occurred in heroin injectors. Seventy cases occurred in England; the remainder occurred in Scotland (12 cases), Wales (2 cases) and the Republic of Ireland (4 cases). Overall, 40 (45%) of the 88 cases were laboratory confirmed by the detection of botulinum neurotoxin in serum, or by the isolation of C. botulinum from wounds. Of the 40 cases in 2004, 36 occurred in England, and of the 12 that were laboratory confirmed, 10 were due to type A. There was some geographical clustering of the cases during 2004, with most cases occurring in London and in the Yorkshire and Humberside region of northeast England.


Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
MENFIL A ORELLANA-BARRIOS ◽  
Kenneth Nugent ◽  
Camilo Pena ◽  
Herman Sanchez-Barrios ◽  
Jose R Lopez-Gutierrez

Background: Hypertension epidemiological studies in developing regions of the world like rural Guatemala are lacking. Methods: A sample size of 1,104 subjects (552 females, all 18 years or older) was obtained through quota and geographical clustering in the entire Department of Sololá, Guatemala. Descriptive statistics and logistic regression were used. Results: Average systolic, diastolic and mean arterial pressures were significantly higher in men compared to women (116.24 vs. 113.80 mmHg, 75.24 mmHg vs. 72.69 mmHg, and 88.91 mmHg vs. 86.39 mmHg, respectively; all with p<0.05). The crude prevalence of HT was 12.5 % with no gender differences. Women had a significantly higher mean BMI than men (26.25 vs. 24.71, p< 0.001). An abnormally high WC was found in 12.7% of men and in 50.7% of women. Significant associations were found between the presence of HT, age ≥ 55 years and an elevated WC. The single most important isolated risk factor for HT was age in women (OR 6.76, CI 95% 3.59-12.72) and WC in men (OR 3.23, CI 95% 1.52-6.87). Increased BMIs (≥ 25 to 30 or ≥30) were not associated with HT in this study. Residing in Sololá's capital was a protective factor in women (OR 0.33, CI 95% 0.13-0.83). Conclusion: Hypertension and associated anthropometric risk factors are present in rural regions of Guatemala. Significant associations are found between gender, age ≥ 55 years, and increased WC but not with an increased BMI in this population.


Author(s):  
Nunzia Carbonara

Agglomeration economies are positive externalities associated with the co-location of firms within a bounded geographic area. Traditionally, these agglomerative advantages have been expressed in terms of pecuniary externalities and they have been identified as one of the key sources of geographical cluster (GC) competitive advantage. However, in the last years the basics of competition are changed and the ability of firms to create new knowledge is more crucial for success rather than the efficiency in production. This has shifted the attention of scholars on the role of knowledge and learning in GCs. In line with these studies, this chapter suggests that agglomeration economies are related to both pecuniary externalities and knowledge-based externalities. The latter are benefits that co-located firms can gain in terms of development of knowledge. To investigate whether knowledge-based externalities affect geographical clustering of firms, an agent-based model is developed. By using this model, a simulation analysis is carried out.


Author(s):  
Alexandre J. L. Leclercq ◽  
Elisabeth Carniel ◽  
Viviane Chenal-Francisque ◽  
Gabriela Torrea

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