997 resultados para revised spring 2006
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The Ross Sea polynya is among the most productive regions in the Southern Ocean and may constitute a significant oceanic CO2 sink. Based on results from several field studies, this region has been considered seasonally iron limited, whereby a "winter reserve" of dissolved iron (dFe) is progressively depleted during the growing season to low concentrations (~0.1 nM) that limit phytoplankton growth in the austral summer (December-February). Here we report new iron data for the Ross Sea polynya during austral summer 2005-2006 (27 December-22 January) and the following austral spring 2006 (16 November-3 December). The summer 2005-2006 data show generally low dFe concentrations in polynya surface waters (0.10 ± 0.05 nM in upper 40 m, n = 175), consistent with previous observations. Surprisingly, our spring 2006 data reveal similar low surface dFe concentrations in the polynya (0.06 ± 0.04 nM in upper 40 m, n = 69), in association with relatively high rates of primary production (~170-260 mmol C/m**2/d). These results indicate that the winter reserve dFe may be consumed relatively early in the growing season, such that polynya surface waters can become "iron limited" as early as November; i.e., the seasonal depletion of dFe is not necessarily gradual. Satellite observations reveal significant biomass accumulation in the polynya during summer 2006-2007, implying significant sources of "new" dFe to surface waters during this period. Possible sources of this new dFe include episodic vertical exchange, lateral advection, aerosol input, and reductive dissolution of particulate iron.
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We calculate net community production (NCP) during summer 2005-2006 and spring 2006 in the Ross Sea using multiple approaches to determine the magnitude and consistency of rates. Water column carbon and nutrient inventories and surface ocean O2/Ar data are compared to satellite-derived primary productivity (PP) estimates and 14C uptake experiments. In spring, NCP was related to stratification proximal to upper ocean fronts. In summer, the most intense C drawdown was in shallow mixed layers affected by ice melt; depth-integrated C drawdown, however, increased with mixing depth. Delta O2/Ar-based methods, relying on gas exchange reconstructions, underestimate NCP due to seasonal variations in surface Delta O2/Ar and NCP rates. Mixed layer Delta O2/Ar requires approximately 60 days to reach steady state, starting from early spring. Additionally, cold temperatures prolong the sensitivity of gas exchange reconstructions to past NCP variability. Complex vertical structure, in addition to the seasonal cycle, affects interpretations of surface-based observations, including those made from satellites. During both spring and summer, substantial fractions of NCP were below the mixed layer. Satellite-derived estimates tended to overestimate PP relative to 14C-based estimates, most severely in locations of stronger upper water column stratification. Biases notwithstanding, NCP-PP comparisons indicated that community respiration was of similar magnitude to NCP. We observed that a substantial portion of NCP remained as suspended particulate matter in the upper water column, demonstrating a lag between production and export. Resolving the dynamic physical processes that structure variance in NCP and its fate will enhance the understanding of the carbon cycling in highly productive Antarctic environments.
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Traditionally, densities of newly built roadways are checked by direct sampling (cores) or by nuclear density gauge measurements. For roadway engineers, density of asphalt pavement surfaces is essential to determine pavement quality. Unfortunately, field measurements of density by direct sampling or by nuclear measurement are slow processes. Therefore, I have explored the use of rapidly-deployed ground penetrating radar (GPR) as an alternative means of determining pavement quality. The dielectric constant of pavement surface may be a substructure parameter that correlates with pavement density, and can be used as a proxy when density of asphalt is not known from nuclear or destructive methods. The dielectric constant of the asphalt can be determined using ground penetrating radar (GPR). In order to use GPR for evaluation of road surface quality, the relationship between dielectric constants of asphalt and their densities must be established. Field measurements of GPR were taken at four highway sites in Houghton and Keweenaw Counties, Michigan, where density values were also obtained using nuclear methods in the field. Laboratory studies involved asphalt samples taken from the field sites and samples created in the laboratory. These were tested in various ways, including, density, thickness, and time domain reflectometry (TDR). In the field, GPR data was acquired using a 1000 MHz air-launched unit and a ground-coupled unit at 200 and 500 MHz. The equipment used was owned and operated by the Michigan Department of Transportation (MDOT) and available for this study for a total of four days during summer 2005 and spring 2006. The analysis of the reflected waveforms included “routine” processing for velocity using commercial software and direct evaluation of reflection coefficients to determine a dielectric constant. The dielectric constants computed from velocities do not agree well with those obtained from reflection coefficients. Perhaps due to the limited range of asphalt types studied, no correlation between density and dielectric constant was evident. Laboratory measurements were taken with samples removed from the field and samples created for this study. Samples from the field were studied using TDR, in order to obtain dielectric constant directly, and these correlated well with the estimates made from reflection coefficients. Samples created in the laboratory were measured using 1000 MHz air-launched GPR, and 400 MHz ground-coupled GPR, each under both wet and dry conditions. On the basis of these observations, I conclude that dielectric constant of asphalt can be reliably measured from waveform amplitude analysis of GJPR data, based on the consistent agreement with that obtained in the laboratory using TDR. Because of the uniformity of asphalts studied here, any correlation between dielectric constant and density is not yet apparent.
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To provide safe and modern transportation systems and services to individuals who travel in Iowa, the Iowa Department of Transportation has identified three broad-based and far-reaching strategic goals: accessibility, responsiveness and accountability. These goals are outlined in this plan, which is aligned with the Accountable Government Act. In addition, the plan specifically addresses strategic needs to serve our customers, and to respond to trends of a growing population and the ever changing need to enhance and expand Iowa's transportation systems. This plan is a living document, and therefore, will be updated periodically.
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This six page document outlines the regulations for spring turkey hunting in Iowa.
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This three page document outlines the regulations for spring turkey hunting in Iowa.
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Iowa Department of Elder Affairs provides a brief summation of a Departmental program or other important Departmental information in each Legislative Update. The Legislative Update is produced for informational and educational purposes only.
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Quarterly publication of the Governor's Traffic Safety Bureau, Iowa Department of Public Safety containing traffic safety and related information and news articles
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Independence, respect, and equality are values important to all people. These values help define the concepts of autonomy (independence and freedom) and self-determination (the right to make decisions for one’s self). Because these rights are so valued in our society and are something that most of us would value for ourselves, the “least restrictive alternative” should always be considered before taking away a person’s civil and legal rights to make decisions for him or herself. The least restrictive alternative is an option, which allows a person to keep as much autonomy, and self-determination as possible while providing only the level of protection and supervision that is necessary. Some examples may include: representative payee for certain government benefit checks, joint bank accounts or advance directives for health care.
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This booklet is designed to assist those who have been appointed as an attorney-in-fact, those who are considering the need for a power of attorney, or those who have an interest in the subject. This is a general overview of the laws governing powers of attorney and, like most general overviews it will apply in most situations, but not all. Small differences and individual circumstances can be very important in resolving legal problems and the general guidance provided by this booklet cannot take such differences into account. Keep in mind that the laws continually change and information in this booklet is not designed to take the place of legal counsel.
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A quarterly journal of Iowa authors and their works produced by State Historical Society of Iowa. Special Commemorative Issue: Mormon Handcraft Trek
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http://lawdigitalcommons.bc.edu/bclsm/1067/thumbnail.jpg
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This paper investigates the income inequality generated by a jobsearch process when di§erent cohorts of homogeneous workers are allowed to have di§erent degrees of impatience. Using the fact the average wage under the invariant Markovian distribution is a decreasing function of the discount factor (Cysne (2004, 2006)), I show that the Lorenz curve and the between-cohort Gini coe¢ cient of income inequality can be easily derived in this case. An example with arbitrary measures regarding the wage o§ers and the distribution of time preferences among cohorts provides some insights into how much income inequality can be generated, and into how it varies as a function of the probability of unemployment and of the probability that the worker does not Önd a job o§er each period.
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The literature on the welfare costs of ináation universally assumes that the many-person household can be treated as a single economic agent. This paper explores what the heterogeneity of the agents in a household might imply for such welfare analyses. First, we show that allowing for a one-person or for a many-person transacting technology impacts the money demand function and, therefore, the welfare costs of ináation. Second, more importantly, we derive su¢ cient conditions under which welfare assessments which depart directly from the knowledge of the money demand function (as in Lucas (2000)) are robust (invariant) under the number of persons considered in the household. Third, we show that Baileyís (1956) partial-equilibrium measure of the welfare costs of ináation can be obtained as a Örst-order approximation of the general-equilibrium welfare measure derived in this paper using a many-person transacting technology.
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Acoustic estimates of herring and blue whiting abundance were obtained during the surveys using the Simrad ER60 scientific echosounder. The allocation of NASC-values to herring, blue whiting and other acoustic targets were based on the composition of the trawl catches and the appearance of echo recordings. To estimate the abundance, the allocated NASC -values were averaged for ICES-squares (0.5° latitude by 1° longitude). For each statistical square, the unit area density of fish (rA) in number per square nautical mile (N*nm-2) was calculated using standard equations (Foote et al., 1987; Toresen et al., 1998). To estimate the total abundance of fish, the unit area abundance for each statistical square was multiplied by the number of square nautical miles in each statistical square and then summed for all the statistical squares within defined subareas and over the total area. Biomass estimation was calculated by multiplying abundance in numbers by the average weight of the fish in each statistical square then summing all squares within defined subareas and over the total area. The Norwegian BEAM soft-ware (Totland and Godø 2001) was used to make estimates of total biomass.