Water-Use Strategies of Japanese Knotweed (Fallopia japonica)

Japanese knotweed, Fallopia japónica, is an herbaceous perennial that is invasive on many continents, including North America. Stands of Japanese knotweed are often located in riparian regions, disturbed sites, and along roadways. Recent studies have evaluated the impact of Japanese knotweed on the hydrologic cycle. Japanese knotweed may have the ability to markedly decrease stream discharge, potentially because of its high LAI. In the summer of 2010, a two-part study was conducted to determine the impact of water availability on the physiology and morphology of Japanese knotweed. A greenhouse study of Japanese knotweed measured transpiration and other factors that may impact water-use, including photosynthesis, stomatal conductance, vapor pressure deficit, leaf water potential, leaf specific conductance, and instantaneous water use efficiency. Leaf and root biomass allocation was examined as well. Via a field study of Japanese knotweed growing under contrasting moisture regimes, designated dry, intermediate, and wet, LMA, node length and diameter, and stem based hydraulic conductance were compared for each moisture regime. The greenhouse study results demonstrated that Japanese knotweed adjusted parameters to optimize use of water when available. Leaf specific hydraulic conductivity was significantly lower for drought-treated plants, at 0.20±0.01 mmol/s/m2/MPa, compared to 0.34±0.01 mmol/s/m2/MPa for watered plants (P=0.0001). Instantaneous water use efficiency increased significantly following drought treatment, with a mean of 24.22±2.05 pmol/mmol for drought-treated plants, and a mean of 17.92±1.4 pmol/mmol for the watered plants (P=0.0109). Such findings were supported by field study results. Hydraulic conductivity on a stem area basis increased significantly between wet site plants, at L16xl06±0.126xl06 mmol/s/MPa/m2, compared to 6.69x105±1.0x105 mmol/s/MPa/m2 for the intermediate site (P=0.0047) and 4.94x105±0.556xl05 mmol/s/MPa/m2 for the dry site (P=0.0001). Significant differences in LMA and internode length were also found between sites, indicating that variations in morphology may promote successful water use and transport in varied environmental conditions. Taken together, the results of these studies show that Japanese knotweed could impact water supply in invaded areas, whether dry or wet, through alterations in physiological responses and biomass allocation that allow for optimal water use under short-term and long-term moisture conditions

KLEOR: A Knowledge Lite Approach to Explanation Oriented Retrieval

In this paper, we describe precedent-based explanations for case-based classification systems. Previous work has shown that explanation cases that are more marginal than the query case, in the sense of lying between the query case and the decision boundary, are more convincing explanations. We show how to retrieve such explanation cases in a way that requires lower knowledge engineering overheads than previously. We evaluate our approaches empirically, finding that the explanations that our systems retrieve are often more convincing than those found by the previous approach. The paper ends with a thorough discussion of a range of factors that affect precedent-based explanations, many of which warrant further research

Combining and choosing case base maintenance algorithms

Case-Based Reasoning (CBR) uses past experiences to solve new problems. The quality of the past experiences, which are stored as cases in a case base, is a big factor in the performance of a CBR system. The system's competence may be improved by adding problems to the case base after they have been solved and their solutions verified to be correct. However, from time to time, the case base may have to be refined to reduce redundancy and to get rid of any noisy cases that may have been introduced. Many case base maintenance algorithms have been developed to delete noisy and redundant cases. However, different algorithms work well in different situations and it may be difficult for a knowledge engineer to know which one is the best to use for a particular case base. In this thesis, we investigate ways to combine algorithms to produce better deletion decisions than the decisions made by individual algorithms, and ways to choose which algorithm is best for a given case base at a given time. We analyse five of the most commonly-used maintenance algorithms in detail and show how the different algorithms perform better on different datasets. This motivates us to develop a new approach: maintenance by a committee of experts (MACE). MACE allows us to combine maintenance algorithms to produce a composite algorithm which exploits the merits of each of the algorithms that it contains. By combining different algorithms in different ways we can also define algorithms that have different trade-offs between accuracy and deletion. While MACE allows us to define an infinite number of new composite algorithms, we still face the problem of choosing which algorithm to use. To make this choice, we need to be able to identify properties of a case base that are predictive of which maintenance algorithm is best. We examine a number of measures of dataset complexity for this purpose. These provide a numerical way to describe a case base at a given time. We use the numerical description to develop a meta-case-based classification system. This system uses previous experience about which maintenance algorithm was best to use for other case bases to predict which algorithm to use for a new case base. Finally, we give the knowledge engineer more control over the deletion process by creating incremental versions of the maintenance algorithms. These incremental algorithms suggest one case at a time for deletion rather than a group of cases, which allows the knowledge engineer to decide whether or not each case in turn should be deleted or kept. We also develop incremental versions of the complexity measures, allowing us to create an incremental version of our meta-case-based classification system. Since the case base changes after each deletion, the best algorithm to use may also change. The incremental system allows us to choose which algorithm is the best to use at each point in the deletion process

Should You Disclose a Data Breach via Social Media? Evidence from US Listed Companies

Data breaches represent one of the main concerns for executives across all sectors. Data breaches open a period of crisis for the affected firm and require them to disclose complex information to a variety of stakeholders in a timely and proper manner. This paper investigates the relationship between social media disclosure of a data breach and its cost, as proxied by the response of the affected firm’s stock price. Using an event study methodology on a sample of 32 data breaches from 29 US publicly-traded firms from 2011 to 2014, we find that social media disclosure exacerbates the negative stock price’ s response to the announcement. However, such a negative association is contingent on firm’s visibility on traditional media with social media disclosure having a beneficial effect for low-visibility companies

Closed-loop communication during out-of-hospital resuscitation:Are the loops really closed?

Training for effective communication in high-stakes environments actively promotes targeted communicative strategies. One oft-recommended strategy is closed-loop communication (CLC), which emphasises three components – call-out, checkback, and closing of the loop – to signal understanding. Using CLC is suggested to improve clinical outcomes, but research indicates that medical practitioners do not always apply CLC in team communication. Our paper analyses a context in which speakers’ linguistic choices are guided by explicit recommendations during training, namely out-of-hospital cardiac arrest (OHCA) resuscitation. We examined 20 real-life OHCA resuscitations to determine whether paramedics adopt CLC in the critical first five minutes after the arrival of the designated team leader (a paramedic specially trained in handling OHCA resuscitation), and what other related communication strategies may be used. Results revealed that standard form CLC was not consistently present in any of the resuscitations despite opportunities to use it. Instead, we found evidence of non-standard forms of CLC and closed-ended communication (containing the first two components of standard CLC). These findings may be representative of what happens when medical practitioners communicate in time-critical, real-life contexts where responses to directives can be immediately observed, and suggest that CLC may not always be necessary for effective communication in these contexts

Interim Report on Studies of the Mw ~7.9 Earthquake of 3 May 2006, Kingdom of Tonga

The very large and rare Mw ~7.9 Earthquake of 3 May 2006 in the Kingdom of Tonga aroused great interest among both Tongan scientists and their colleagues in Australia, New Zealand, and the United States. To investigate the earthquake we formed a collaborative research group of scientists from Australia, New Zealand, Tonga, and the United States. We brought in seven seismographs from Australia and the US to supplement the three-station network already in Tonga and eight GPS receivers primarily for the islands west of the earthquake epicenter. In addition, we made coastal observations to determine the regional pattern of subsidence associated with the earthquake. The GPS instruments can measure horizontal and vertical motion quite precisely, but only after the earthquake from the time of deployment onward, except for some sites on Tongatapu, Vava’u, and Lifuka that had been occupied by GPS receivers in the past. This report describes our efforts.Ministry of Lands and Survey, Kingdom of TongaGeoscience AustraliaGeological and Nuclear Sciences, New ZealandThe National Science Foundation, U.S.A.Institute for Geophysic