The Effects of Critical Habitat Designation on Housing Supply: An Analysis of California Housing Construction Activity

Under the Endangered Species Act, the U.S. Fish and Wildlife Service is required to designate critical habitat for listed species. Designation could result in modification to or delay of residential development projects within habitat boundaries, generating concern over potential housing market impacts. This paper draws upon a large dataset of municipal-level (FIPS) building permit issuances and critical habitat designations in California over a 13-year period to identify changes in the spatial and temporal pattern of development activity associated with critical habitat designation. We find that the proposal of critical habitat results in a 20.5% decrease in the annual supply of housing permits in the short-run and a 32.6% decrease in the long-run. Further, the percent of the FIPS area that is designated as critical habitat significantly affects the number of permits issued. We also find that the impact varies across the two periods in which critical habitat is designated and by the number of years relative to when critical habitat was first proposed.

American Refugees and Asylum Seekers in Canada

American Soldier, Jeremy Hinzman, deserted his Iraq bound unit in 2003 and fled to Canada where he now seeks asylum with his wife and young son. The legal implications of his case are explored against the background of the American and Canadian political landscapes. The Canadian Court’s ultimate denial of his application evidences sweeping changes in Canada’s approach to International Law

The design of the housing for leak detection device

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 42).Small leaks in pipes cause huge losses of water, wasting the energy and money put into cleaning the water and pumping it to the point of the leak. Detecting these small leaks is currently not very accurate or practical to do over an entire system of pipes. A device is being developed which detects leaks from within the pipe using the drop in pressure at the point of a leak. This thesis addresses the geometric needs for deploying the sensors in the pipe. The housing for the device needs to navigate pipes while keeping the sensors close enough to the wall to get a good reading. The housing is made up of a frame with flexible cantilevers which sensor holders pivot about to stay flush with the wall. After looking at other devices which navigate pipes, the geometric constraints of the pipe were used to create an initial design. The first iteration was manufactured to check for validity of the design. Many changes have to be made to the design based on the results from manufacturing the first iteration.by Naomi W. Zabel.S.B

Conditions for free magnetic monopoles in nanoscale square arrays of dipolar spin ice

We study a modified frustrated dipolar array recently proposed by M\"{o}ller and Moessner [Phys. Rev. Lett. \textbf{96}, 237202 (2006)], which is based on an array manufactured lithographically by Wang \emph{et al.} [Nature (London) \textbf{439}, 303 (2006)] and consists of introducing a height offset $h$ between islands (dipoles) pointing along the two different lattice directions. The ground-states and excitations are studied as a function of $h$. We have found, in qualitative agreement with the results of M\"{o}ller and Moessner, that the ground-state changes for $h>h_{1}$, where $h_{1}= 0.444a$ ($a$ is the lattice parameter or distance between islands). In addition, the excitations above the ground-state behave like magnetic poles but confined by a string, whose tension decreases as $h$ increases, in such a way that for $h\approx h_1$ its value is around 20 times smaller than that for $h=0$. The system exhibits an anisotropy in the sense that the string tension and magnetic charge depends significantly on the directions in which the monopoles are separated. In turn, the intensity of the magnetic charge abruptly changes when the monopoles are separated along the direction of the longest axis of the islands. Such a gap is attributed to the transition from the anti to the ferromagnetic ground-state when $h=h_1$.Comment: 6 pages, 7 figures. Published versio

Cellular expression of interleukin 2 (IL-2) and its receptor (IL-2R, CD25) in lung tumours

In view of the unclear prognostic and diagnostic role of interleukin 2 (IL-2) and its receptor in human tumours, we examined the cellular expression of IL-2 and of the subunit α of its receptor (IL-2Rα, CD25) in relation to the proliferative activity of various subtypes of lung tumours. The immunocytochemical ABC technique was applied to archival tissue material of neuroendocrine lung tumours: lung carcinoids, including typical carcinoids (TC), atypical carcinoids (AC) and small-cell lung cancers (SCLC) and squamous cell lung cancers (non-small cell lung cancers, NSCLC). Expression of IL-2 was detected in all types of lung tumours. The highest frequency of IL-2 expression (93%) was noted and the most pronounced semi-quantitatively evaluated expression of IL-2 was detected in AC tumour cells. The expression was more pronounced as compared to neoplastic SCLC (p = 0.01) and NSCLC cells (p = 0.005). The results suggest a negative correlation between IL-2 expression and the proliferative activity of tumour cells (evaluated by expression of Ki-67) in AC. The frequency of detection of IL-2 receptor (IL-Rα, CD25) was the highest in NSCLC (94%). Semi-quantitative expression of IL-2R, like that of IL-2, also dominated in the group of atypical lung carcinoids but manifested a significant difference only as compared to typical carcinoids (p = 0.014). Within the groups of tumours studied no correlation could be detected between cellular expressions of IL-2 and IL-2R. Our results demonstrate variable expression of IL-2 and its receptor in various types of lung tumours, but no simple relationship could be detected between tissue expression of the markers and proliferative activity. Appraisal of the diagnostic and/or prognostic significance of the results requires further study

Nambu monopoles interacting with lattice defects in two-dimensional artificial square spin ice

The interactions between an excitation (similar to a pair of Nambu monopoles) and a lattice defect are studied in an artificial two-dimensional square spin ice. This is done by considering a square array of islands containing only one island different from all others. This difference is incorporated in the magnetic moment (spin) of the "imperfect" island and several cases are studied, including the special situation in which this distinct spin is zero (vacancy). We have shown that the two extreme points of a malformed island behave like two opposite magnetic charges. Then, the effective interaction between a pair of Nambu monopoles with the deformed island is a problem involving four magnetic charges (two pairs of opposite poles) and a string. We also sketch the configuration of the field lines of these four charges to confirm this picture. The influence of the string on this interaction decays rapidly with the string distance from the defect.Comment: 7 pages, 13 figure

Evolutionary responses by native species to major anthropogenic changes to their ecosystems: Pacific salmon in the Columbia River hydropower system

The human footprint is now large in all the Earth’s ecosystems, and construction of large dams in major river basins is among the anthropogenic changes that have had the most profound ecological consequences, particularly for migratory fishes. In the Columbia River basin of the western USA, considerable effort has been directed toward evaluating demographic effects of dams, yet little attention has been paid to evolutionary responses of migratory salmon to altered selective regimes. Here we make a first attempt to address this information gap. Transformation of the free-flowing Columbia River into a series of slackwater reservoirs has relaxed selection for adults capable of migrating long distances upstream against strong flows; conditions now favour fish capable of migrating through lakes and finding and navigating fish ladders. Juveniles must now be capable of surviving passage through multiple dams or collection and transportation around the dams. River flow patterns deliver some groups of juvenile salmon to the estuary later than is optimal for ocean survival, but countervailing selective pressures might constrain an evolutionary response toward earlier migration timing. Dams have increased the cost of migration, which reduces energy available for sexual selection and favours a nonmigratory life history. Reservoirs are a benign environment for many non-native species that are competitors with or predators on salmon, and evolutionary responses are likely (but undocumented). More research is needed to tease apart the relative importance of evolutionary vs. plastic responses of salmon to these environmental changes; this research is logistically challenging for species with life histories like Pacific salmon, but results should substantially improve our understanding of key processes. If the Columbia River is ever returned to a quasinatural, free-flowing state, remaining populations might face a Darwinian debt (and temporarily reduced fitness) as they struggle to re-evolve historical adaptations

Survival and Selection of Migrating Salmon from Capture-Recapture Models with Individual Traits

Capture–recapture studies are powerful tools for studying animal population dynamics, providing information on population abundance, survival rates, population growth rates, and selection for phenotypic traits. In these studies, the probability of observing a tagged individual reflects both the probability of the individual surviving to the time of recapture and the probability of recapturing an animal, given that it is alive. If both of these probabilities are related to the same phenotypic trait, it can be difficult to distinguish effects on survival probabilities from effects on recapture probabilities. However, when animals are individually tagged and have multiple opportunities for recapture, we can properly partition observed trait-related variability into survival and recapture components. We present an overview of capture–recapture models that incorporate individual variability and develop methods to incorporate results from these models into estimates of population survival and selection for phenotypic traits. We conducted a series of simulations to understand the performance of these estimators and to assess the consequences of ignoring individual variability when it exists. In addition, we analyzed a large data set of .153 000 juvenile chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) of known length that were PIT-tagged during their seaward migration. Both our simulations and the case study indicated that the ability to precisely estimate selection for phenotypic traits was greatly compromised when differential recapture probabilities were ignored. Estimates of population survival, however, were far more robust. In the chinook salmon and steelhead study, we consistently found that smaller fish had a greater probability of recapture. We also uncovered length-related survival relationships in over half of the release group/river segment combinations that we observed, but we found both positive and negative relationships between length and survival probability. These results have important implications for the management of salmonid populations

Measuring Lateral Magnetic Structure in Thin Films Using Polarized Neutron Reflectometry

Polarized neutron reflectometry (PNR) has long been applied to measure the magnetic depth profile of thin films. In recent years, interest has increased in observing lateral magnetic structures in a film. While magnetic arrays patterned by lithography and submicron-sized magnetic domains in thin films often give rise to off-specular reflections, micron-sized ferromagnetic domains on a thin film produce few off-specular reflections and the domain distribution information is contained within the specular reflection. In this paper, we will first present some preliminary results of off-specular reflectivity from arrays of micron-sized permalloy rectangular bars. We will then use specular reflections to study the domain dispersion of an exchange-biased Co/CoO bilayer at different locations of the hysteresis loop.Comment: 10 pages, 3 figurres, PNCMI 2002, Juelich, German

Origin of the reduced exchange bias in epitaxial FeNi(111)/CoO(111) bilayer

We have employed Soft and Hard X-ray Resonant Magnetic Scattering and Polarised Neutron Diffraction to study the magnetic interface and the bulk antiferromagnetic domain state of the archetypal epitaxial Ni$_{81}$Fe$_{19}$(111)/CoO(111) exchange biased bilayer. The combination of these scattering tools provides unprecedented detailed insights into the still incomplete understanding of some key manifestations of the exchange bias effect. We show that the several orders of magnitude difference between the expected and measured value of exchange bias field is caused by an almost anisotropic in-plane orientation of antiferromagnetic domains. Irreversible changes of their configuration lead to a training effect. This is directly seen as a change in the magnetic half order Bragg peaks after magnetization reversal. A 30 nm size of antiferromagnetic domains is extracted from the width the (1/2 1/2 1/2) antiferromagnetic magnetic peak measured both by neutron and x-ray scattering. A reduced blocking temperature as compared to the measured antiferromagnetic ordering temperature clearly corresponds to the blocking of antiferromagnetic domains. Moreover, an excellent correlation between the size of the antiferromagnetic domains, exchange bias field and frozen-in spin ratio is found, providing a comprehensive understanding of the origin of exchange bias in epitaxial systems.Comment: 8 pages, 5 figures, submitte