Hong Kong Observatory currently uses a series of meteorological instruments, including long-range LIDAR (light detection and ranging) systems, to provide alerting services of low-level windshear and turbulence for Hong Kong International Airport. For some events that are smaller in spatial dimensions and are rapidly changing, such as low altitude windshear and turbulence associated with buildings or man-made structures, it would be necessary to involve meteorological instruments that offer greater spatial resolution. Therefore, the Observatory has set up a short-range LIDAR on the roof of the AsiaWorld-Expo during the summers over the past several years, conducting field research on the feasibility of strengthening early alerting for windshear and turbulence over the north runway’s eastern arrival runway (Runway 25RA) and developing an automated early alerting algorithm. This paper takes the pilot reports for Runway 25RA during the 2013 field research as verification samples, using different thresholds for radial wind velocity spatial and temporal changes detected by the short-range LIDAR to calculate the relative operating characteristic (ROC) curve, and analyzes its early alerting performance.

Background: Long-lived marine megavertebrates (e.g. sharks, turtles, mammals, and seabirds) are inherently vulnerable to anthropogenic mortality. Although some mathematical models have been applied successfully to manage these animals, more detailed treatments are often needed to assess potential drivers of population dynamics. In particular, factors such as age-structure, density-dependent feedbacks on reproduction, and demographic stochasticity are important for understanding population trends, but are often difficult to assess. Lemon sharks (Negaprion brevirostris) have a pelagic adult phase that makes them logistically difficult to study. However, juveniles use coastal nursery areas where their densities can be high.

Results: We use a stage-structured, Markov-chain stochastic model to describe lemon shark population dynamics from a 17-year longitudinal dataset at a coastal nursery area at Bimini, Bahamas. We found that the interaction between delayed breeding, density-dependence, and demographic stochasticity accounts for 33 to 49% of the variance in population size.

Conclusions: Demographic stochasticity contributed all random effects in this model, suggesting that the existence of unmodeled environmental factors may be driving the majority of interannual population fluctuations. In addition, we are able to use our model to estimate the natural mortality rate of older age classes of lemon sharks that are difficult to study. Further, we use our model to examine what effect the length of a time series plays on deciphering ecological patterns. We find that—even with a relatively long time series—our sampling still misses important rare events. Our approach can be used more broadly to infer population dynamics of other large vertebrates in which age structure and demographic stochasticity are important.

Fine particulate matter (PM_2.5) was collected in Shiprock, New Mexico, a small community located near two coal–fired power plants and numerous abandoned uranium mine tailing sites. Eleven PM_2.5 samples were collected for 96 h over three sampling periods (April/May 2009, November 2009, and October/November, 2010). Nine samples were analyzed for 64 elements using inductively coupled plasma–mass spectrometry. B, Bi, Cu, Pb, Sb, Sn, and Zn were observed in at least eight samples at levels indicative of anthropogenic enrichment (enrichment factors between 30 and 650). All the seven elements could be explained by coal–combustion processes. B, Bi, and Sb are enriched in coals; Cu, Pb, Sn, and Zn are chalcophile–lithophile or chalcophile elements, all with appreciable affinity for sulfur, a component of coal. Principal component analysis also supported these findings. Four major sources (percent variance) were identified: soil (61%), coal combustion (17%), industrial (11%), and sea salt (5%). Concentrations of elements associated with coal combustion in Shiprock were lower than levels observed in other industrially influenced cities. This was explained by Shiprock’s location west of the power plants. Back trajectories indicated that winds arrive to Shiprock from the W, SW, and NW, but the power plants are located to the east (upwind) of the city. Samples were also analyzed for uranium (0.002–0.02 ng/m³) and other metals associated with mine tailings (Sr, Mo). All metals were detected but at low levels, and concentrations did not vary predictably with wind direction. Hence, the tailings sites could not be attributed as the source.

Biological systematics studies suggest that species are discretized in niche space. That is, rather than seeing a continuum of organism types with respect to continuous environmental variations, observers instead find discrete species or clumps of species, with one clump separated from another in niche space by a gap. Here, using a simple one dimensional model with a smoothly varying environmental condition, we investigate conditions for a discrete niche partitioning instability of a continuously varying species structure in the context of asexually reproducing microbes. We find that significant perturbation of translational invariance is required for instability, but that conditions for such perturbations might reasonably occur, for example, through influence of boundary conditions.

The topological contribution of a Gauss–Bonnet term in four dimensions to black hole entropy opens up the possibility of a violation of the second law of thermodynamics in black hole mergers. We show, however, that the second law is not violated in the regime where Einstein–Gauss–Bonnet holds as an effective theory and black holes can be treated thermodynamically. For mergers of anti-de Sitter (AdS) black holes, the second law appears to be violated even in Einstein gravity; we argue, however, that the second law holds when gravitational potential energy is taken into account.

This article analyzes Rousseau’s political theory of private property, fills a lacuna in the literature, and develops a novel interpretation of Rousseau’s apparently contradictory remarks. Although Rousseau was critical of private property, he did not advocate a clear and easy solution to the problems he discerned. Instead, he put forth a highly differentiated perspective that was principled and pragmatic. He rooted the legitimacy of private ownership in an ideal theory of republican property rights, which refers primarily to the normative principle of reciprocity. In his opinion, a balance of private property rights is indispensable to a well-ordered society and a just republic not only because it binds the state, society, and citizen together, and not only because it secures the independence of individual citizens from each other, but also because it enhances political legitimacy and reciprocity. On these principled grounds, Rousseau’s theory rules out “collectivist” solutions as much as vast differences in wealth and “absolutist” theories of more or less unlimited private property rights. Instead, his theory builds on the republican idea of private property as a public political institution. Within this ideal framework, Rousseau allows for certain non-ideal deviations in particular circumstances on prudential grounds.

A visible femtosecond laser is shown to be capable of selectively inactivating a wide spectrum of microorganisms in a wavelength and pulse width dependent manner. However, the mechanism of how a visible femtosecond laser affects the viability of different microorganisms is still elusive. In this paper, the cellular surface properties, membrane integrity and metabolic rate of Escherichia coli (E. coli) irradiated by a visible femtosecond laser (λ = 415 nm, pulse width = 100 fs) with different exposure times were investigated. Our results showed that femtosecond laser treatment for 60 min led to cytoplasmic leakage, protein aggregation and alternation of the physical properties of the E. coli cell membrane. In comparison, a 10 min exposure of bacteria to femtosecond laser irradiation induced an immediate reduction of 75% in the glucose-dependent respiratory rate, while the cytoplasmic leakage was not detected. Results from enzymatic assays showed that oxidases and dehydrogenases involved in the E. coli respiratory chain exhibited divergent susceptibility after laser irradiation. This early commencement of respiratory inhibition after a short irradiation is presumed to have a dominant effect on the early stage of bacteria inactivation.

In this paper, we construct several infinite families of diagonal quartic surfaces ax⁴ + by⁴ + cz⁴ + dw⁴ = 0 (where a, b, c, d are non-zero integers) with infinitely many rational points and satisfying the condition abcd is not a square. In particular, we present an infinite family of diagonal quartic surfaces defined over ℚ with Picard number equal to one and possessing infinitely many rational points. Further, we present some sextic surfaces of type ax⁶ + by⁶ + cz⁶ + dwⁱ = 0, i = 2, 3, or 6, with infinitely many rational points.

The Montreal Protocol is generally credited as a successful example of international cooperation in response to a global environmental problem. As a result, the production and consumption of ozone-depleting substances has declined rapidly, and it is expected that atmospheric ozone concentrations will return to their normal ranges toward the end of this century. This paper applies the social-ecological system framework and common-pool resource theory to explore the congruence between successful resolution of small-scale appropriation problems and ozone regulation, a large-scale pollution problem. The results of our analysis correspond closely to past studies of the Protocol that highlight the importance of attributes such as a limited number of major industrial producers, advances in scientific knowledge, and the availability of technological substitutes. However, in contrast to previous theoretical accounts that focus on one or a few variables, our analysis suggests that its success may have been the result of interactions between a wider range of SES attributes, many of which are associated with successful small-scale environmental governance. Although carefully noting the limitations of drawing conclusions from the analysis of a single case, our analysis reveals the potential for fruitful interplay between common-pool resource theory and large-scale pollution problems.

In this paper we use a case study of the Rhine River to examine the relevance of Common Pool Resource (CPR) Theory for two conditions in which it has not been extensively tested: large scale international water management and pollution problems. For that purpose, we link variation in pollution abatement to a set of explanatory variables proposed by CPR theory. Causal inference is established through process tracing and a series of within-case comparison across actor groups (i.e. riparian nations, industry, and agriculture), resource types (i.e. point source, and non-point source pollutants), and time periods (1976–1986, when treaties provided a limited basis for collective action and pollution abatement, and 1987–2001, when the Rhine Action Plan proved more successful). According to our analysis, a number of CPR variables can help understanding cooperation for pollution abatement in the Rhine case. These include physical attributes such as clear hydrological boundaries; governance factors such as the articulation of monitoring and decision-making at different governance levels and the proportional allocation of costs and benefits of abating pollution; and actor factors like the small size, trust and homogeneity of some actor groups and leadership. Other variables proposed by CPR theory proved to be irrelevant or in need of qualification. These include the right to self-organize and to participate in decision-making, communication and resource-dependence. Finally, two variables, not emphasized by CPR theory, proved relevant: the occurrence of external disturbances and the role of interest groups. We conclude that CPR theory is valuable for explaining pollution management in large trans-boundary river basins, but requires qualification and extension.