Optimal Detection of a Change Point in a Poisson Process for Different Observation Schemes

Abstract.  Change point problems are considered where at some unobservable time the intensity of a point process ( T_n ), n ∈  N , has a jump. For a given reward functional we detect the change point optimally for different information schemes. These schemes differ in the available information. We consider three information levels, namely sequential observation of ( T_n ), ex post decision after observing the point process up to a fixed time t * and a combination of both observation schemes. In all of these cases the detection problem is viewed as an optimal stopping problem which can be solved by deriving a semimartingale representation of the gain process and applying tools from filtering theory.     

Exploring structural habitat heterogeneity in sustainable urban drainage systems (SUDS) for urban biodiversity support

Implementation of sustainable urban drainage systems (SUDS) as part of cities’ transition towards climate resilience encompasses unique opportunities to enhance urban nature qualities. SUDS include individual elements integrated in the urban landscape, e.g. rain gardens or wet basins, which are usually constructed with low structural heterogeneity. Structural heterogeneity of habitats is, however, associated with a high degree of biodiversity. This study explored potentials of habitat heterogeneity enhancement in SUDS using structural heterogeneity as a proxy for biodiversity potential. In an interdisciplinary workshop, landscape architects and urban ecologists designed individual SUDS elements with enhanced structural habitat heterogeneity, hereafter bio-SUDS. The redesigned SUDS elements were infiltration trench, curb extension, rain garden, swale, wet basin, and dry basin. To evaluate the bio-SUDS designs, we developed an index of habitat heterogeneity in SUDS based on registration of 45 structurally important components. The conversion from standard SUDS to bio-SUDS entailed substantial increases in structural heterogeneity ranging from 4 to 18 additional components within elements. Larger bio-SUDS elements returned higher index scores, but the relative score increases were substantial for all bio-SUDS and in the range of a factor of 2–5.5. Increased terrain differences, meandering edges, stones, gravel, boulders, deadwood, and brown roof-like vegetation were the components most often employed in the bio-SUDS designs. In conclusion, implementation of bio-SUDS has potential to increase structural habitat heterogeneity thereby providing habitat for biodiversity in urban green areas. The developed bio-SUDS index can assist in future assessments of ecological qualities in designs and real-world SUDS elements.     

Risk Analysis for Invasive Species: General Framework and Research Needs

A joint workshop was convened by the Society for Risk Analysis Ecological Risk Assessment Specialty Group and the Ecological Society of America Theoretical Ecology Section to provide independent scientific input into the formulation of methods and processes for risk assessment of invasive species. In breakout sessions on (1) the effects of invasive species on human health, (2) effects on plants and animals, (3) risk analysis issues and research needs related to entry and establishment of invasive species, and (4) risk analysis issues and research needs related to the spread and impacts of invasive species, workshop participants discussed an overall approach to risk assessment for invasive species. Workshop participants agreed on the need for empirical research on areas in which data are lacking, including potential invasive species, native species and habitats that may be impacted by invasive species, important biological processes and phenomena such as dispersal, and pathways of entry and spread for invasive species. Participants agreed that theoretical ecology can inform the process of risk assessment for invasive species by providing guidelines and conceptual models, and can contribute to improved decision making by providing a firm biological basis for risk assessments.     

New Fathers' Labor Supply: Does Child Health Matter?*

Objective. We estimate the effect of poor child health on the labor supply of fathers post‐welfare reform, using a national sample of mostly unwed parents and their children—a group at high risk of living in poverty. Method. We control for a rich set of covariates, include state fixed effects, and test for the endogeneity of child health by estimating bivariate probit models. Results. We find that having a young child in poor health reduces the father's probability of being employed by four percentage points. The effect appears to be strongest among fathers who cohabit with, but are not married to, the child's mother. Conclusion. The results suggest a potential source by which young children with serious health problems may receive lower levels of health investment than their healthier peers—their fathers' reduced likelihood of being employed.     

The fertility impact of alternative family planning distribution channels in Indonesia

Clinic-based distribution of contraceptive commodities is expensive per unit distributed. This situation has fueled the search for alternative means of delivery. Comparing the performance of alternatives is straightforward if the output measure is a count of commodities distributed, but comparing actual fertility impacts is another matter. I use data from the 1991 Indonesia Demographic and Health Survey to assess the extent of difference among the eventual fertility outcomes of users supplied with similar commodities through varying sources. When the “modern” methods of pill, IUD, and injection are grouped together, the fertility of users supplied with these commodities differs markedly according to their source of supply. I find little evidence for self-selecting of users into supply channels. This result implies that fertility differentials by source are likely due to characteristics of the distribution channels.     

Carbon Labelling and Low‐income Country Exports: A Review of the Development Issues

This article discusses the carbon accounting and carbon‐labelling schemes being developed to address growing concerns over climate change. Its particular concern is their impact on small stakeholders, especially low‐income countries. The popular belief that trade is by definition problematic is not true; carbon efficiencies elsewhere in the supply chain may more than offset emissions from transportation. Indeed, low‐income countries may offer important opportunities for carbon emission reductions because of their favourable climatic conditions and use of low energy‐intensive production techniques. However, their effective inclusion in labelling schemes will require innovative solutions to provide low‐cost data collection and certification.     

Habitat use in basking Northern water (Nerodia sipedon) and Eastern garter (Thamnophis sirtalis) snakes in urban New Jersey

The habitat use of basking northern water (Nerodia sipedon) and Eastern garter (Thamnophis sirtalis) snakes was examined along the Raritan Canal, an urbanized area of central New Jersey. There were significant differences between the two species with respect to cloud cover, canopy cover, and the distance to the path and the water, but not with respect to percent of the body exposed to the sun, and percent of the snake that was visible. Water snakes were more likely to bask on bushes, branches and logs than were garter snakes. Garter snakes basked when both the air and water temperature were lower than did water snakes. The lack of basking sites in the water suggests that those along shore are important, including the low hanging branches used by the watersnakes.     

With a Little Help from Your Friends: The Importance of High‐quality Friendships on Early Adolescent Adjustment

The unique contributions of peer acceptance, friendship, and victimization to adjustment were examined. How these relational systems moderate the influence of one another to influence adjustment was also investigated. Friendship quality, a unique aspect of friendship, was expected to be especially important for adjustment when other relational systems were poor. A total of 238 fifth to eighth graders (boys = 109) participated in the survey‐style paradigm. Youth participants completed measures assessing their friendships and peer relationships. Teachers provided assessments of adjustment. Adolescents who had lower levels of peer acceptance, number of friends, and friendship quality had greater teacher‐reported maladjustment. Friendship quality was also an important buffer against adjustment problems when peer acceptance and number of friends were low. The outcomes of this article suggest that an approach that includes examining the quality of adolescents' friendships, peer interactions, and interactive models of relationship dimensions are informative for understanding adolescents' general adjustment.     

The self in the other: Aleksandr Griboedov’s Orient

While scholars of Russian orientalism have diverged somewhat in their interpretation of Aleksandr Griboedov, they have in the main viewed him as a supporter of Russian expansion and seen in his works a justification of Russia’s conquests in the East. This essay seeks to complicate that view. By taking a comprehensive look at Griboedov’s Eastern-themed works (including his poems “There, Where Flows the Alazani”, “Kal'ianchi”, and “Predators on the Chegem”, the play Georgian Night and a series of editorials, letters, and travel notes written from the Caucasus and Persia) and situating them in the context of contemporary literary and political debates, the author argues that Griboedov undercuts rather than supports the orientalist conception of the East’s alterity. By portraying “Eastern” ways as possibilities latent within all humans and by pointing out the Russian past in the Persian present, Griboedov is able to question Russia’s role in the Caucasus and to explore the costs of Russia’s progress towards European-style civilization.