Effect of solar UV‐B exclusion on the phytoplankton community in a sub‐tropical mountain reservoir: a mesocosm study

A mesocosm experiment was conducted over a 4 week period to investigate the response of a phytoplankton community in a mountain freshwater reservoir to solar UV‐B exclusion. The mesocosms were filled with water taken from the depth of 0.30 m in the reservoir, and exposed to near‐ambient solar UV‐B (+UV‐B) and solar UV‐B exclusion (?UV‐B). The resulting chlorophyll‐a (Chl‐a), carotenoids, soluble sugars, algal composition and algal abundance were analysed. The study results indicated that carotenoids, carbohydrates and species distribution were affected under the ?UV‐B treatment. The carotenoid concentration was generally higher under the +UV‐B treatment than under the ?UV‐B treatment. The sucrose and glucose concentrations were affected differently by the UV‐B treatments, although both sugars strongly decreased under the +UV‐B treatment by the end of the experiment. The sucrose and glucose concentrations exhibited similar distribution patterns to those of carotenoids for the +UV‐B treatment, suggesting that these sugars could be directly involved in secondary metabolism. In contrast, the fructose content did not exhibit significant differences between UV‐B treatments. The Chl‐a concentration exhibited a progressive decrease during the experiment for both UV‐B treatments. Although no significant impact of UV‐B exclusion on the Chl‐a concentration was observed in this study, a slightly higher concentration was observed for the ?UV‐B treatment. The total phytoplankton biovolume (BV) exhibited a pattern similar to that of the Chl‐a concentration. Analysis of the phytoplankton composition revealed 52 species. However, because some species and classes were extremely difficult to identify, only 46 species from seven classes (Cyanophyceae, Chlorophyceae, Bacillariophyceae, Euglenophyceae, Charophyceae, Dinophyceae, Xanthophyceae) were unambiguously identified and considered for the UV‐B treatments. Chlorophyceae, Bacillariophyceae and Cyanophyceae comprised about 78% of the identified species. Aulacoseira granulata and Cyclotella meneghiniana, followed by Ceratium hirundinella, were the most abundant species. Principal component analysis, using sampling periods and algal densities (PCA‐1), indicated a heterogeneous phytoplankton assemblage, whereas PCA‐2, with algal densities and biochemical variables (soluble carbohydrates, Chl‐a and carotenoids), indicated that biochemical parameters could provide qualitative information about La Angostura phytoplankton community responses to quality of the sunlight.     

Economic diversification of a single-asset tourism city: evidence from Antalya†

It is often argued that the growth of single-asset tourism places is fragile because it is vulnerable to economic fluctuations and is based on specialization and localization economies that lead to an ever stronger lock-in process of path-dependent urban economic development and, in the end, slow growth. In this paper, it is doubted whether a high urban tourism growth implies an ever stronger specialization and an ever stronger lock-in. This paper shows that the growth of tourism stimulates the growth of related and unrelated industries and generates a diversification of the economy, even though some other sectors are crowded out. Antalya (Turkey) is selected as a case-study area not only because its economy is dominated by tourism (it is a good example of a single-asset tourism city), but also because its economy shows a tendency to economic diversification at the sectoral level. This diversification tendency is shown by means of a shift-share analysis and Herfindahl indexes.     

Capital Deployment Roundtable: A Discussion of Corporate Investment and Payout Policy

U.S. companies are now reportedly earning record‐high operating returns on capital while at the same time continuing to set new records both for corporate cash holdings and distributions to investors in the form of dividends and stock repurchases. But are most of these companies really maximizing value? And what role, if any, do these large distributions play in creating value? These are the two main questions that are addressed by a small group that includes two senior corporate executives and two representatives of well‐known activist investors. A number of panelists suggest that many companies, in misguided efforts to maximize returns on capital, have been using hurdle rates that are too high and so sacrificing value‐adding investment opportunities. As evidence for this claim, they cite evidence that, in recent years, the companies that have achieved the highest stock market returns appear to have made conscious decisions to reduce their returns on capital to pursue higher growth. Another increasingly common charge against U.S. companies is their tendency to pay out excessive capital to investors, especially in the form of stock repurchases at prices that turn out to be too high. But this last practice, however widespread, may not be as troubling as it has been made out to be. Although it involves a wealth transfer from existing to selling shareholders, overall investor value is lost only if such buybacks lead to corporate underinvestment. But, as a number of panelists (including the activist investors) point out, such payouts of capital have generally functioned as a demonstration of corporate managers' commitment to investing and operating with the optimal, or value‐maximizing, level of capital—neither too much nor too little.     

Optimal Water Allocation from Subsurface Dams: A Risk-Based Optimization Approach

Subsurface dams, strongly advocated in the 1992 United Nations Agenda-21, have been widely studied to increase groundwater storage capacity. However, an optimal allocation of augmented water with the construction of the subsurface dams to compensate for the water shortage during dry periods has not so far been investigated. This study, therefore, presents a risk-based simulation–optimization framework to determine optimal water allocation with subsurface dams, which minimizes the risk of water shortage in different climatic conditions. The developed framework was evaluated in Al-Aswad falaj, an ancient water supply system in which a gently sloping underground channel was dug to convey water from an aquifer via the gravity force to the surface for irrigation of downstream agricultural zones. The groundwater dynamics were modeled using MODFLOW UnStructured-Grid. The data of boreholes were used to generate a three-dimensional stratigraphic model, which was used to define materials and elevations of five-layer grid cells. The validated groundwater model was employed to assess the effects of the subsurface dam on the discharge of the falaj. A Conditional Value-at-Risk optimization model was also developed to minimize the risk of water shortage for the augmented discharge on downstream agricultural zones. Results show that discharge of the falaj is significantly augmented with a long-term average increase of 46.51%. Moreover, it was found that the developed framework decreases the water shortage percentage in 5% of the worst cases from 87%, 75%, and 32% to 53%, 32%, and 0% under the current and augmented discharge in dry, normal, and wet periods, respectively.

     

The causality between FDI and sector-specific production in Turkey: evidence from threshold cointegration with regime shifts

This article considers bidirectional nonlinear cointegration relation between FDI and industrial output in Turkey. The data cover the monthly period 2005:1–2013:10 for the time series of total industrial production, 36 sub-industrial sectors’ production and FDI. Following nonlinear threshold cointegration and VECMs, the article yields that (i) total industrial production and nine sub-industrial productions have positive long-run impact on FDI with significant error corrections, (ii) six sub-industrial productions have short-term influence on FDI, (iii) FDI has long-run positive impulse on total industrial production and nine sub-industrial productions with some significant error corrections and (iv) FDI affects four sub-industrial productions in the short run as well as in the long run. The results of VECMs from (i) also reveal that the all short-term adjustment parameters are found significant and powerful in 10 typical regimes (Regime-1s) and in 5 extreme regimes (Regime-2s). Finally, the outcome of VECMs from (iii) yields that short-term adjustment parameters are found significant and powerful in two typical regimes and in four extreme regimes. Eventually, considering FDI’s positive impact in the short and long run, this article suggests that policymakers promote specifically the FDI inflows to the sectors of intermediate goods, manufacture of beverages, manufacture of rubber and plastic and manufacture of other nonmetallic mineral products.     

Hedging the black swan: Conditional heteroskedasticity and tail dependence in S&P500 and VIX

The recent financial crisis has accentuated the fact that extreme outcomes have been overlooked and not dealt with adequately. While extreme value theories have existed for a long time, the multivariate variant is difficult to handle in the financial markets due to the prevalent heteroskedasticity embedded in most financial time series, and the complex extremal dependence that cannot be conveniently captured by a single structure. Moreover, most of the existing approaches are based on a limiting argument in which all variables become large at the same rate. In this paper, we show how the conditional approach of Heffernan and Tawn (2004) can be implemented to model extremal dependence between financial time series. We use a hedging example based on VIX futures to demonstrate the flexibility and superiority of the conditional approach against the conventional OLS regression approach.     

Environmental governance for sustainable tourism development: Collaborative networks and organisation building in the Antalya tourism region

For more than two decades the attainment of sustainable environmental quality and the protection of environmental assets have been at the forefront of central policy issues in global tourism development. Recently, it has been argued that collaborative and associative forms of governance among tourism companies and other related agents are growing in importance in the drive for sustainable and environmentally sensitive tourism. Despite the increasing number of debates on the role of networking on tourism they are not well supported by empirical studies, and still far from explain how such networks can contribute to the sustainable development of territories. This paper aims to contribute to previous literature by analysing together governance networks and literature on sustainable development, and by providing empirical findings that highlight the importance of governance networks in sustainable tourism development, the importance of different scales of collaborative governance networks and the role of organisation building for environmentally sustainable tourism development in Antalya. The paper offers analytical findings on the networks of environmental governance among different types of tourism organisations based on a company-level survey, which reveals an increase in local collaboration and self-help networking based on local concerns and endogenous dynamics among the different actors in tourism. Unfortunately, the findings show that environmental motivations fall far behind economic considerations in networking practices.     

Value Creation by Active Investors (and Its Potential for Addressing Social Problems)

A distinguished Columbia academic discusses the methods and outcomes of “active investing” with the co‐founder of a leading private equity firm and a former senior partner of a well‐known hedge fund. In the case studies used by both panelists to illustrate their investment selection and management processes, the investors provided not only capital, but oversight and expertise that helped bring about significant increases in the productivity and value of their portfolio companies. What's more, in both cases, the changes that contributed to high returns for investors also ended up having major benefits for the companies' non‐investor stakeholders, especially their consumers. In the first of the two cases, Paul Hilal explains the thinking behind Pershing Square's $1.1 billion purchase of 14% of the Canadian Pacific Railway in 2012. With the help of intensive “fundamental” analysis of the company, Hilal recognized that Canadian Pacific was substantially underperforming its rival, the Canadian National Railway, in a number of important ways. And when CP's management and board rejected his plan for changes, Hilal led a proxy battle that ended in a landslide victory for the proposed slate of directors, including Hilal himself. Then, after bringing in a new CEO, the restructured board presided over operating changes that, during Pershing's four‐year ownership, increased the market value of CP from $8 billion to $30 billion. By 2016, when Pershing sold its investment (for $4 billion), Canadian Pacific was “shipping 20% more freight … 40% faster than ever before, with record on‐time performance, 40% fewer locomotives, 35% fewer people, and 14% improved fuel efficiency—all while maintaining an industry‐leading safety record.” In the second case, Russ Carson describes the success of Welsh, Carson, Anderson, and Stowe in turning its purchase in 1998 of a single oncology practice in Denver into a publicly traded company with more than 90 outpatient cancer centers throughout the U.S. When it was sold in 2011, US Oncology was producing $4 billion in revenue while employing 1,000 oncologists, who, as significant equity owners, shared in the success of Welsh Carson. Using modern management techniques to create “enormous efficiencies out of an extraordinarily fragmented system,” Carson and his colleagues created “the single largest—and, by all accounts, most reputable—outpatient provider of cancer services in the country.” One of the keys to this success was “getting the doctors to spend their time seeing patients, not looking for records,” which contributed greatly to Welsh Carson's ability to improve “both the quantity and quality of cancer care in the 90 communities that we were operating in.”