scholarly journals High-order interactions maintain or enhance structural robustness of a coffee agroecosystem network

2021 ◽  
Author(s):  
Cecilia González González ◽  
Emilio Mora Van Cauwelaert ◽  
Denis Boyer ◽  
Ivette Perfecto ◽  
John Vandermeer ◽  
...  
Keyword(s):  
Structural Characteristics ◽  
High Order ◽  
Network Robustness ◽  
List Type ◽  
Ecological Network ◽  
Context Specificity ◽  
Methodological Issues ◽  
The Face ◽  
Node Removal ◽  
Key Nodes

AbstractThe capacity of highly diverse systems to prevail has proven difficult to explain. In addition to methodological issues, the inherent complexity of ecosystems and issues like multicausality, non-linearity and context-specificity make it hard to establish general and unidirectional explanations. Nevertheless, in recent years, high order interactions have been increasingly discussed as a mechanism that benefits the functioning of highly diverse ecosystems and may add to the mechanisms that explain their persistence. Until now, this idea has been explored by means of hypothetical simulated networks. Here, we test this idea using an updated and empirically documented network for a coffee agroecosystem. We identify potentially key nodes and measure network robustness in the face of node removal with and without incorporation of high order interactions. We find that the system’s robustness is either increased or unaffected by the addition of high order interactions, in contrast with randomized counterparts with similar structural characteristics. We also propose a method for representing networks with high order interactions as ordinary graphs and a method for measuring their robustness.HighlightsThe robustness of a coffee-associated ecological network is either increased or unaffected by the incorporation of high order interactions.A method is proposed for representing high order interactions in ordinary networks.A method is proposed to measure the robustness of networks with high order interactions.High order interactions may promote the persistence of diverse ecosystems.

scholarly journals Beyond ratios - flexible and resilient nurse staffing options to deliver cost-effective hospital care and address staff shortages: a simulation and economic modelling study

2020 ◽  
Author(s):  
Peter Griffiths ◽  
Christina Saville ◽  
Jane E Ball ◽  
Jeremy Jones ◽  
Thomas Monks
Keyword(s):  
Cost Effectiveness ◽  
Significant Proportion ◽  
Nurse Staffing ◽  
Cost Savings ◽  
Cost Effective ◽  
Adverse Outcomes ◽  
List Type ◽  
Economic Modelling ◽  
The Face ◽  
Hospital Wards

AbstractBackgroundIn the face of pressure to contain costs and make best use of scarce nurses, flexible staff deployment (floating staff between units and temporary hires) guided by a patient classification system may appear an efficient approach to meeting variable demand for care in hospitals.ObjectivesWe modelled the cost-effectiveness of different approaches to planning baseline numbers of nurses to roster on general medical/surgical units while using flexible staff to respond to fluctuating demand.Design and SettingWe developed an agent-based simulation model, where units move between being understaffed, adequately staffed or overstaffed as staff supply and demand, measured by the Safer Nursing Care Tool, varies. Staffing shortfalls are addressed firstly by floating staff from overstaffed units, secondly by hiring temporary staff. We compared a standard staffing plan (baseline rosters set to match average demand) with a ‘resilient’ plan set to match higher demand, and a ‘flexible’ plan, set at a lower level. We varied assumptions about temporary staff availability. We estimated the effect of unresolved low staffing on length of stay and death, calculating cost per life saved.ResultsStaffing plans with higher baseline rosters led to higher costs but improved outcomes. Cost savings from low baseline staff largely arose because shifts were left under staffed. Cost effectiveness for higher baseline staff was improved with high temporary staff availability. With limited temporary staff available, the resilient staffing plan (higher baseline staff) cost £9,506 per life saved compared to the standard plan. The standard plan cost £13,967 per life saved compared to the flexible (low baseline) plan. With unlimited temporary staff, the resilient staffing plan cost £5,524 per life saved compared to the standard plan and the standard plan cost £946 per life saved compared with the flexible plan. Cost-effectiveness of higher baseline staffing was more favourable when negative effects of high temporary staffing were modelled.ConclusionFlexible staffing can be guided by shift-by-shift measurement of patient demand, but proper attention must be given to ensure that the baseline number of staff rostered is sufficient.In the face of staff shortages, low baseline staff rosters with high use of flexible staff on hospital wards is not an efficient or effective use of nurses whereas high baseline rosters may be cost-effective. Flexible staffing plans that minimise the number of nurses routinely rostered are likely to harm patients because temporary staff may not be available at short notice.Study registration: ISRCTN 12307968Tweetable abstractEconomic model of hospital wards shows low baseline staff levels with high use of flexible staff are not cost-effective and don’t solve nursing shortages].What is already known?Because nursing is the largest staff group, accounting for a significant proportion of hospital’s variable costs, ward nurse staffing is frequently the target of cost containment measuresStaffing decisions need to address both the baseline staff establishment to roster, and how best to respond to fluctuating demand as patient census and care needs varyFlexible deployment of staff, including floating staff and using temporary hires, has the potential to minimise expenditure while meeting varying patient need, but high use of temporary staff may be associated with adverse outcomes.What this paper addsOur simulation shows that low baseline staff rosters that rely heavily on flexible staff increase the risk of patient death and provide cost savings largely because wards are often left short staffed under real world availability of temporary staff.A staffing plan set to meet average demand appears to be cost effective compared to a plan with a lower baseline but is still associated with frequent short staffing despite the use of flexible deployments.A staffing plan with a higher baseline, set to meet demand 90% of the time, is more resilient in the face of variation and may be highly cost effective

scholarly journals Methodological Issues in Analyses of Use and Adequacy of Community Services in Rural Areas: With an Application to Legal Services in the Northeast

1976 ◽  
Vol 5 (2) ◽  
pp. 29-39 ◽  
Author(s):  
Cleve E. Willis ◽  
Charles O. Crawford
Keyword(s):  
Rural Areas ◽  
Community Services ◽  
Legal Services ◽  
List Type ◽  
Estimation Technique ◽  
Type Number ◽  
Methodological Issues ◽  
Utilization Behavior

Three major problems appear common to recent research efforts aimed at measurement and assessment of the adequacy of community services. These include:(i)difficulties and inconsistencies which relate to the definition and interpretation of utilization behavior,(ii)econometric misspecification—e.g., omission of critical variables affecting needs or use—, and(iii)choice of inappropriate estimation technique when the dependent variable (e.g., use or non-use of the service) is dichotomous.

International Criminal Tribunal for the Former Yugoslavia (ICTY) (Trial Chamber): Prosecutor v. Milošć (Decision Concerning an Amicus Curiae)

2002 ◽  
Vol 41 (6) ◽  
pp. 1344-1346
Keyword(s):  
International Criminal ◽  
International Criminal Tribunal ◽  
Trial Chamber ◽  
Former Yugoslavia ◽  
List Type ◽  
Relevant Factor ◽  
Amicus Curiae ◽  
The Face ◽  
The Hague

The accused has complained about publications in two newspapers. The first was published on the 7th of September, 2002 in the Haagsche Courant, a Dutch newspaper in The Hague, and the second on the 13th September, 2002 in the Kultura, a Bulgarian newspaper in Sofia, Bulgaria. Both publications resulted from interviews given by Mr. Michail Wladimiroff, one of the three amici curiae in this case.The publication in the Haagsche Courant was captioned: “Wladimiroff: Already Enough Evidence Against Milosevic.” Mr. Wladimiroff is reported as saying, “If this trial were only about Kosovo and one had to draw up the balance now, Milosevic would certainly be convicted. A link has been established between the army and the police, the warring parties in Kosovo and Milosevic himself.”Mr. Wladimiroff explained that he had been misquoted, and that what he had said was that “we have seen during the Prosecution case at least on the face of it, there is a link between the offences in Kosovo and the accused. That may not be for all events, but even if it were half of it, it is a relevant factor for the Trial Chamber when reaching a verdict.”

Geometrical Nonlinear Effects in the Dynamic Response of Sandwich Beams

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Itay Odessa ◽  
Oded Rabinovitch ◽  
Yeoshua Frostig
Keyword(s):  
Dynamic Response ◽  
Nonlinear Dynamic ◽  
High Order ◽  
Theory Approach ◽  
Nonlinear Frequency ◽  
Sandwich Beams ◽  
Nonlinear Dynamic Response ◽  
The Core ◽  
Geometrical Nonlinear ◽  
The Face

Abstract The geometrical nonlinear dynamic response of sandwich beams is studied using a dynamic high-order nonlinear model. The model is derived using the variational principle of virtual work and uses the Extended High-Order Sandwich Panel Theory approach with consideration of two interfaces between the three layers. A first-order shear deformation theory is adopted for the face sheets, while the kinematic assumption of high-order small deformations that account for out-of-plane compressibility are considered for the core layer. The nonlinearity of the dynamic model is introduced by considering geometrically nonlinear kinematic relations in the face sheets. The nonlinear kinematic relations and the dynamic modeling aim to evaluate the effects of the two features and their coupling on the response. The nonlinear dynamic response of sandwich beams is studied through two numerical cases and comparison of the nonlinear results with their linear counterparts. The first case looks into the coupling of the global geometrical nonlinear behavior with the dynamic behavior. The second case focuses on the local instability of the face sheets and its interaction with the compressibility of the core in the dynamic response of soft core sandwich beams. The comparison of linear and nonlinear dynamic response in the two cases sheds light on the coupling of the geometrical nonlinear and dynamic behaviors. Among other features, the latter is expressed by nonlinear attractors, higher modes response, nonlinear frequency response, and significant wrinkling response.

scholarly journals Methodological Issues and Controversies in COVID-19 Coagulopathy: A Tale of Two Storms

2020 ◽  
Vol 26 ◽  
pp. 107602962094539
Author(s):  
Samuel A Berkman ◽  
Victor F Tapson
Keyword(s):  
Venous Thromboembolism ◽  
Thromboembolic Event ◽  
Body Part ◽  
Current Evidence ◽  
Methodological Issues ◽  
Post Discharge ◽  
The Face ◽  
Disease Impact ◽  
Anti Body ◽  
Intermediate Dose

Venous thromboembolism, occlusion of dialysis catheters, circuit thrombosis in ECMO devices, all in the face of prophylactic and sometimes even therapeutic anti-coagulation, are frequent features of COVID-19 coagulopathy. The trials available to guide clinicians are methodologically limited. There are several unresolved controversies including 1) Should all hospitalized patients with COVID-19 receive prophylactic anti-coagulation? 2) Which patients should have their dosage escalated to intermediate dose? 3) Which patients should be considered for full-dose anti-coagulation even without a measurable thromboembolic event and how should that anti-coagulation be monitored? 4) Should patients receive post-discharge anti-coagulation? 5) What thrombotic issues are related to the various medications being used to treat this coagulopathy? 6) Is anti-phospholipid anti-body part of this syndrome? 7) How do the different treatments for this disease impact the coagulation issues? The aims of this article are to explore these questions and interpret the available data based on the current evidence.

Reactions between uranium veins and their host rocks in Vendée and Limousin (France)

1981 ◽  
Vol 44 (336) ◽  
pp. 417-423 ◽  
Author(s):  
M. Cathelineau ◽  
J. Leroy
Keyword(s):  
Structural Characteristics ◽  
Wall Rock ◽  
Structural Features ◽  
Gangue Mineral ◽  
List Type ◽  
Vein Formation ◽  
Wall Rock Alteration ◽  
Rock Alteration ◽  
Host Rocks ◽  
Basic Rocks

AbstractHydrothermal uranium veins, associated with the Hercynian leucogranites show important variations in their mineralogical, chemical and structural features in relation to the host rock lithology. These are described with particular reference to the Chardon deposit, Vendée where the veins cut granite, basic lithologies, and shales. The following features are described: 1Changes in the thickness of veins near to contact zones, particularly those between granites and basic lithologies, lamprophyres, and shales.2Changes in the gangue mineral assemblage with the preferential development of carbonate in veins cutting basic lithologies, and of silica in veins which cut granite.3Paragenetic zoning in the veins in passing from granites to their metamorphic aureoles.Comparisons between deposits of Vendée, Limousin, and Erzgebirge allow the following generalizations to be made: 1Open faults and subsequent mineralization are concentrated at boundaries between competent and more plastic lithologies.2Mineralizing fluids cause wall-rock alteration characterized by the removal of Si from granite and of Ca, Mg, Fe from metamorphic and basic rocks.3The chemical and structural characteristics of wallrocks are important controls on the mineralization but in acid lithologies the main controls on the pitchblende vein formation are the structural characteristics of the wallrock.

scholarly journals Evolution of under Water Sides of Ice Shelves and Icebergs

1987 ◽  
Vol 9 ◽  
pp. 176-182 ◽  
Author(s):  
Olav Orheim
Keyword(s):  
Vertical Wall ◽  
Weddell Sea ◽  
Mature Stage ◽  
List Type ◽  
Near Surface ◽  
Ice Shelves ◽  
Side Scan Sonar ◽  
Water Line ◽  
Formative Stage ◽  
The Face

A systematic programme of side-scan sonar and plumb- line soundings was carried out in the Weddell Sea area in 1985 to measure the under-water sides of ice shelves and icebergs. From these observations the following model is suggested for the evolution of the ice front:(1)Initial stage: fracturing of the ice shelves takes place along smooth, curvi-linear segments with vertical faces.(2)Formative stage: the freshly formed vertical face is eroded both by wave and swell action around the water line, by small calvings from the undercut, overhanging subaerial face, and by submarine melting. The melting has a minimum at 50–100 m depth, and increases with depth to a rate of around 10 m a−1at 200 m, This is about twice the rate of erosion at the water line. The variation in melting with depth results from a combination of summer melting by near-surface water, and year-round melting by water masses that are increasingly warmer than the pressure melting-point with depth.(3)Mature stage: this stage is reached after a few years of exposure. The backward erosion of the face leads to a shape with a prominent under-water “nose” with a maximum projection to more than 50 m at 50–100 m depth. The ramp above this slopes upwards to meet the vertical wall about 5 m below the water line. The ice below the nose is melted back beyond the above-water face. There is no net buoyancy and ice shelves at this mature stage are generallynotup-warped at the front.

Contrast Sensitivity in Human Visual Areas and Its Relationship to Object Recognition

2002 ◽  
Vol 87 (6) ◽  
pp. 3102-3116 ◽  
Author(s):  
Galia Avidan ◽  
Michal Harel ◽  
Talma Hendler ◽  
Dafna Ben-Bashat ◽  
Ehud Zohary ◽  
...  
Keyword(s):  
Object Recognition ◽  
High Sensitivity ◽  
Ventral Stream ◽  
High Order ◽  
Object Representations ◽  
Lateral Occipital Complex ◽  
Line Drawings ◽  
Visual Areas ◽  
The Face ◽  
Contrast Invariance

An important characteristic of visual perception is the fact that object recognition is largely immune to changes in viewing conditions. This invariance is obtained within a sequence of ventral stream visual areas beginning in area V1 and ending in high order occipito-temporal object areas (the lateral occipital complex, LOC). Here we studied whether this transformation could be observed in the contrast response of these areas. Subjects were presented with line drawings of common objects and faces in five different contrast levels (0, 4, 6, 10, and 100%). Our results show that indeed there was a gradual trend of increasing contrast invariance moving from area V1, which manifested high sensitivity to contrast changes, to the LOC, which showed a significantly higher degree of invariance at suprathreshold contrasts (from 10 to 100%). The trend toward increased invariance could be observed for both face and object images; however, it was more complete for the face images, while object images still manifested substantial sensitivity to contrast changes. Control experiments ruled out the involvement of attention effects or hemodynamic “ceiling” in producing the contrast invariance. The transition from V1 to LOC was gradual with areas along the ventral stream becoming increasingly contrast-invariant. These results further stress the hierarchical and gradual nature of the transition from early retinotopic areas to high order ones, in the build-up of abstract object representations.

High-order free vibration analysis of FGM sandwich plates with non-monotonically graded flexible core

2016 ◽  
Vol 20 (6) ◽  
pp. 759-780 ◽  
Author(s):  
Ming Liu ◽  
Jun Liu ◽  
Yuansheng Cheng
Keyword(s):  
Free Vibration ◽  
Vibration Analysis ◽  
Shear Deformation Theory ◽  
Free Vibration Analysis ◽  
Core Layer ◽  
Functionally Graded ◽  
High Order ◽  
Sandwich Plates ◽  
The Face ◽  
Flexible Core

Free vibration analysis of sandwich plates with non-monotonically graded flexible core is studied using a high-order sandwich panel theory. The non-monotonically graded flexible core is considered as two monotonically graded flexible core layers. In this high-order theory, the first-order shear deformation theory is used for the face sheets and a 3D-elasticity solution of weak core is employed for each single core layer. The laminated two-layered core is analyzed and formulated by the mixed layer-wise theory. Based on the continuity of the displacements and transverse stresses at the interfaces of the face sheets and the core, equations of motion are derived by Hamilton’s principle. The accuracy of the present approach is validated by comparing with the numerical results obtained from finite element method and good agreements are reached. Parametric study is also conducted to investigate the effect of distribution of functionally graded material properties, the monotonically graded core thickness ratio, and the thickness-to-side ratio on the vibration frequency.

scholarly journals Hybrid high-order discretizations combined with Nitsche’s method for Dirichlet and Signorini boundary conditions

2020 ◽  
Vol 40 (4) ◽  
pp. 2189-2226 ◽  
Author(s):  
Karol L Cascavita ◽  
Franz Chouly ◽  
Alexandre Ern
Keyword(s):  
Boundary Conditions ◽  
Error Estimates ◽  
High Order ◽  
Optimal Error Estimates ◽  
Optimal Error ◽  
Nitsche’S Method ◽  
Nitsche's Method ◽  
Elliptic Model ◽  
The Face ◽  
Signorini Boundary Conditions

Abstract We present two primal methods to weakly discretize (linear) Dirichlet and (nonlinear) Signorini boundary conditions in elliptic model problems. Both methods support polyhedral meshes with nonmatching interfaces and are based on a combination of the hybrid high-order (HHO) method and Nitsche’s method. Since HHO methods involve both cell unknowns and face unknowns, this leads to different formulations of Nitsche’s consistency and penalty terms, either using the trace of the cell unknowns (cell version) or using directly the face unknowns (face version). The face version uses equal-order polynomials for cell and face unknowns, whereas the cell version uses cell unknowns of one order higher than the face unknowns. For Dirichlet conditions, optimal error estimates are established for both versions. For Signorini conditions, optimal error estimates are proven only for the cell version. Numerical experiments confirm the theoretical results and also reveal optimal convergence for the face version applied to Signorini conditions.

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