Scenario-based modeling in industrial information systems

This manuscript addresses the creation of scenario-based models to reason about the behavior of existing industrial information systems. In our approach the system behavior is modeled in two steps that gradually introduce detail and formality. This manuscript addresses the first step, where text-based descriptions, in the form of structured rules, are used to specify how the system is or should be regulated. Those rules can be used to create behavioral snapshots, which are collections of scenario-based descriptions that represent different instances of the system behavior. Snapshots are specified in an intuitive and graphical notation that considers the elements from the problem domain and permit designers to discuss and validate the externally observable behavior, together with the domain experts. In the second step (not fully covered in this manuscript), the system behavior is formalized with an executable model. This formal model, which in our approach is specified using the Colored Petri Net (CP-nets) language, allows the system internal behavior to be animated, simulated, and optimized. The insights gained by experimenting with the formal model can be subsequently used for reengineering the existing system

Evaluating presentation formats of local climate change in community planning with regard to process and outcomes

This study synthesizes two evaluations of a local climate change planning process in a rural town in British Columbia (Canada), which was supported through landscape visualizations. First, the impact of the visualizations, based on scientific environmental modeling and presented in three different presentation formats, verbal/visual presentation, posters and a virtual globe, was evaluated with regard to immediate impacts during the process. Second, the long-term impacts on decision-making and actual outcomes were evaluated in a retrospective evaluation 22 months after the end of the initial planning process. Two results are highlighted: according to the quantitative pre-/post-questionnaires, the visualizations contributed to increased awareness and understanding. Most importantly, the retrospective evaluation indicated that the process informed policy, operational and built changes in Kimberley, in which the landscape visualizations played a role. The post interviews with key decision-makers showed that they remembered most of the visualizations and some decision-makers were further using them, particularly the posters. The virtual globe seemed to be not a "sustainable" display format suitable for formal decision-making processes such as council meetings though. That may change with the further mainstreaming of visualization technologies or mobile devices. Until then, we recommend using display formats that can be re-used following a specific planning event such as an Open House, to ensure on-going support for effective decision-making over the longer-term

Rationale and design of the hip fracture accelerated surgical treatment and care track (hip attack) trial : A protocol for an international randomised controlled trial evaluating early surgery for hip fracture patients

Introduction Annually, millions of adults suffer hip fractures. The mortality rate post a hip fracture is 7%-10% at 30 days and 10%-20% at 90 days. Observational data suggest that early surgery can improve these outcomes in hip fracture patients. We designed a clinical trial - HIP fracture Accelerated surgical TreaTment And Care tracK (HIP ATTACK) to determine the effect of accelerated surgery compared with standard care on the 90-day risk of all-cause mortality and major perioperative complications. Methods and analysis HIP ATTACK is a multicentre, international, parallel group randomised controlled trial (RCT) that will include patients ≥45 years of age and diagnosed with a hip fracture from a low-energy mechanism requiring surgery. Patients are randomised to accelerated medical assessment and surgical repair (goal within 6 h) or standard care. The co-primary outcomes are (1) all-cause mortality and (2) a composite of major perioperative complications (ie, mortality and non-fatal myocardial infarction, pulmonary embolism, pneumonia, sepsis, stroke, and life-threatening and major bleeding) at 90 days after randomisation. All patients will be followed up for a period of 1 year. We will enrol 3000 patients. Ethics and dissemination All centres had ethics approval before randomising patients. Written informed consent is required for all patients before randomisation. HIP ATTACK is the first large international trial designed to examine whether accelerated surgery can improve outcomes in patients with a hip fracture. The dissemination plan includes publishing the results in a policy-influencing journal, conference presentations, engagement of influential medical organisations, and providing public awareness through multimedia resources. Trial registration number NCT02027896; Pre-results

Prospective observational cohort study of the association between antiplatelet therapy, bleeding and thrombosis in patients with coronary stents undergoing noncardiac surgery

Background: The perioperative management of antiplatelet therapy in noncardiac surgery patients who have undergone previous percutaneous coronary intervention (PCI) remains a dilemma. Continuing dual antiplatelet therapy (DAPT) may carry a risk of bleeding, while stopping antiplatelet therapy may increase the risk of perioperative major adverse cardiovascular events (MACE). Methods: Occurrence of Bleeding and Thrombosis during Antiplatelet Therapy In Non-Cardiac Surgery (OBTAIN) was an international prospective multicentre cohort study of perioperative antiplatelet treatment, MACE, and serious bleeding in noncardiac surgery. The incidences of MACE and bleeding were compared in patients receiving DAPT, monotherapy, and no antiplatelet therapy before surgery. Unadjusted risk ratios were calculated taking monotherapy as the baseline. The adjusted risks of bleeding and MACE were compared in patients receiving monotherapy and DAPT using propensity score matching. Results: A total of 917 patients were recruited and 847 were eligible for inclusion. Ninety-six patients received no antiplatelet therapy, 526 received monotherapy with aspirin, and 225 received DAPT. Thirty-two patients suffered MACE and 22 had bleeding. The unadjusted risk ratio for MACE in patients receiving DAPT compared with monotherapy was 1.9 (0.93–3.88), P=0.08. There was no difference in MACE between no antiplatelet treatment and monotherapy 1.03 (0.31–3.46), P=0.96. Bleeding was more frequent with DAPT 6.55 (2.3–17.96) P=0.0002. In a propensity matched analysis of 177 patients who received DAPT and 177 monotherapy patients, the risk ratio for MACE with DAPT was 1.83 (0.69–4.85), P=0.32. The risk of bleeding was significantly greater in the DAPT group 4.00 (1.15–13.93), P=0.031. Conclusions: OBTAIN showed an increased risk of bleeding with DAPT and found no evidence for protective effects of DAPT from perioperative MACE in patients who have undergone previous PCI

Fire in the riparian zone: Characteristics and ecological consequences

We review the current understandings of the frequency, spatial distributions, mechanisms, and ecological consequences of fire in riparian zones. Riparian zones are well known for influencing many ecological processes at local to landscape scales, and fire can have an important ecosystem-scale influence on them. Riparian zones differ from surrounding uplands in their biophysical templates, moisture regimes and disturbance regimes; as a consequence the characteristics and effects of fire are different than in adjacent uplands. Fire impacts on riparian zones vary proportionally with the severity and extent of burning in the catchment and are affected by stream size. Riparian zones can act as a buffer against fire and therefore as a refuge for fire-sensitive species. However, under some circumstances, such as dry pre-fire climatic conditions and the accumulation of dry fuel, riparian areas become corridors for fire movement. Fire incursion into riparian zones creates canopy gaps and drier conditions, which allow subsequent build up of dead wood and establishment of fire adapted species. In concert, this increases fuel loads and the probability of another fire. Secondary effects of riparian fire include altering nutrient fluxes and cycling, increasing sediment loads, and stimulating erosion. We conclude that riparian fires are potentially important in shaping ecological characteristics in many regions, but this is poorly quantified. A better understanding of riparian fire regimes is essential to assess the effects of fire in helping shape the complex ecological characteristics of riparian zones over the longer-term

Flood-deposited wood creates regeneration niches for riparian vegetation on a semi-arid South African river

Question: The formation of large woody debris (LWD) piles during floods has significant impacts on riparian succession through pioneering plants often establishing in association with wood. We assess the importance of LWD for seed regeneration of riparian plants after a century-scale flood disturbance in a semi-arid environment. Location: The Sabie River within Kruger National Park in the semi-arid northeast of South Africa. Methods: Our approach was to quantify the riparian soil seed bank, to record the frequency of establishment of riparian plants in woody debris piles, and to conduct experimental outplantings of common riparian trees in plots with and without LWD. Results: We found the abundance and diversity of seedlings were higher in soils taken from wood piles than from open reference areas, and most seedlings were herbaceous species. Surveys indicated that numbers of seedlings recorded within woody debris were significantly greater than in open reference areas or within established vegetation. Seedling establishment in various cover-types also varied for different riparian tree species. Experimental out-planting of seedlings of two riparian tree species (Philenoptera violacea and Combretum erythrophyllum) revealed that, after 433 days, planted seedlings survived only in woody debris piles. Conclusion: LWD formed after a large flood creates heterogeneous patches that may influence post-disturbance regeneration of riparian vegetation by providing a variety of environmental niches for seedlings establishment. We suspect that higher seedling survival in LWD is due to increased moisture (particularly in the dry season) and nutrients, and protection from seasonal flooding and herbivory

Flood-deposited wood debris and its contribution to heterogeneity and regeneration in a semi-arid riparian landscape

We investigated whether large woody debris (LWD) piles create nodes of environmental resources that contribute to the recovery of riparian vegetation and that also augment the heterogeneity and resilience of the riverine system. River and riparian systems are typified by a large degree of heterogeneity and complex interactions between abiotic and biotic elements. Disturbance such as floods re-distribute the resources, such as LWD, and thereby add greater complexity to the system. We examined this issue on a semi-arid savanna river where a ∼100-year return interval flood in 2000 uprooted vegetation and deposited substantial LWD. We investigated the micro-environment within the newly established LWD piles and compared this with conditions at adjacent reference sites containing no LWD. We found soil nutrient concentrations to be significantly higher in LWD piles compared with the reference plots (total N +19%, available P +51%, and total C +36%). Environmental variables within LWD piles and reference sites varied with landscape position in the river-riparian landscape and with LWD pile characteristics. Observed differences were generally between piles located in the terrestrial and riparian areas as compared to piles located on the macro-channel floor. After 3 years the number and cover of woody species were significantly higher when associated with LWD piles, regardless of landscape position or pile type. We conclude that LWD piles formed after large floods act as resource nodes by accumulating fine sediments and by retaining soil nutrients and soil moisture. The subsequent influence of LWD deposition on riparian heterogeneity is discerned at several spatial scales including within and between LWD piles, across landscape positions and between channel types. LWD piles substantially influence the initial developmental of riparian vegetation as the system regenerates following large destructive floods

Postfire response of flood-regenerating riparian vegetation in a semi-arid landscape

Piles of large wood (LW) deposited by major floods in river corridors can interact with naturally occurring wildfires from uplands to impact the regeneration of riparian vegetation. This study examines the spatial and short-term temporal response of riparian vegetation and soil nutrients to fire along the Sabie River, South Africa, with special emphasis on the effects of burned LW piles. At the study site there were 112 species of plants recorded with 28% of species restricted to the burned plots. As expected, vegetation cover was significantly lower in burned plots as compared with the unburned plots 12 months postfire. There was a significant influence of LW on species richness with fewer species recorded in the LW plots. For both fire and LW treatments, plant cover showed a significant change over three years. After an initial increase from 12 to 24 months (postfire) there was a decline in plant cover after 36 months. Species community composition was distinctly different between burned and unburned plots 12 months postfire, and the presence of LW affected species composition for burned plots but not for unburned ones. Time series ordination of LW plots highlighted the changes in species composition over the three years of sampling. Of trees with accumulations of LW within 5 m of their base, 48% had been killed by fire as compared to only 4% with no LW accumulations in close proximity. Soil-available P was significantly higher in the burned plots and even higher with burned LW while there were no effects on soil total N. There was also a significant positive trend between available P in soils and plant vegetation cover. Soil-exchangeable K was also significantly higher and total C significantly lower in the burned and LW plots. Burned plots also had significantly higher soil electrical conductivity (EC) and soil pH. The patchy nature of the studied fire, whose complexity is exacerbated by the distribution of flood deposited LW, acted to create a mosaic of alternate successional states as the riparian community recovers from flooding and the subsequent fire. We suspect that the resultant heterogeneity will increase ecosystem resilience by providing flexibility in the form of more options for a system response to subsequent disturbances

Formation, distribution and ecological consequences of flood-related wood debris piles in a bedrock confined river in semi-arid South Africa

The Sabie River, located within the semi-arid savanna of South Africa, experienced a ∼100-year return interval flood in 2000, providing a rare opportunity to quantify the resultant pattern and consequence of woody debris piles for riparian areas. Biophysical attributes of rivers in arid and semi-arid regions differ strongly from those in mesic regions, but differences in the role and dynamics of woody debris remain largely unknown. Our primary goal was to determine the basic ecology and distribution of wood piles formed by a large infrequent flood in a bedrock-confined river. In particular, we sought to determine the mechanism of pile formation, their position, size, and structural attributes of piles as well as regeneration from resprouting and seedling recruitment within piles in different channel types. We observed relatively distinct patterns of distribution and mechanisms of formation in 421 piles and provide a description of the distribution, abundance and short-term fate of each pile type. Patterns of wood accumulation were largely controlled by characteristics of the trapping sites, particularly toppled trees that remain rooted in their growth location. In general, wood was primarily strewn against toppled, transported and standing trees, though several large piles formed on bedrock outcrops. Buried piles were also discovered upon excavation of depositional features (alluvial mounds). Resprouting of toppled trees with intact roots and living tissues was the dominant mode of vegetation reestablishment in the piles. We observed resprouting in 36% of piles surveyed. Resprouting piles were most common (48%) in the seasonally inundated portion of the macro-channel. Tree seedlings were recorded in 28% of the piles. The flood appeared to create heterogeneity in the establishment of new woody vegetation by forming distinct wood piles from the ruins of the previous riparian forest. Even though the input of wood to semi-arid rivers appears to be a fairly rare occurrence and wood piles are rapidly depleted by decay and fire, we expect their influence will be long-lived, preserved in the pattern of vegetation establishment and alluvial mounds within the macro-channel

Post-flooding distribution and characteristics of large woody debris piles along the semi-arid Sabie River, South Africa

The formation of large woody debris (LWD) piles has a profound impact on channel patterns and riparian succession in temperate rivers. The opportunity to study LWD along the Sabie River, a river in the semi-arid region of Kruger National Park, South Africa, arose in February 2000 after a significant flood (c. 100-year return interval) removed a large proportion of the fully mature riparian forest and other plant communities. Much of the uprooted vegetation was deposited as LWD piles (woody vegetation accumulations deposited on the ground > 0.1m 3) throughout the riparian and upland zones. In this article we describe the spatial distribution patterns of LWD as related to geomorphic channel type and flood frequency zone, and assess pile composition characteristics six months after the flood. Within the areas surveyed there were 68 LWD piles per hectare, the median size of LWD piles was 4.6 m3 but pile sizes (by volume) varied widely. Pool/rapid geomorphic channel types had the highest density of LWD piles (79 ha-1) and the largest piles (by volume) were in the bedrock anastomosing channels (mean = 124 m3). Piles were larger in the seasonal and ephemeral flood frequency zones (mean = 54 m 3 and 55 m3) than piles in the active zone (c. 2 m3). The patterns of distribution and volume of LWD will affect the subsequent development of vegetation communities as debris piles form a mosaic of patches of surviving organisms and propagules that can strongly influence the initial trajectory of succession. The amount, distribution, and subsequent decomposition of LWD are different from that reported for temperate rivers, suggesting that the role of LWD may be different on non-floodplain rivers such as the Sabie in semi-arid South Africa