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Automatic computer-based analyses of histological sections which are differently stained require that they are related to each other. Most registration methods are only able to perform rigid-body motion and are sensitive to noise and artifacts. Histological images, however, are accompanied by several artifacts and different contrasts, which require a nonrigid registration. In this paper, we present a hierarchical nonrigid registration algorithm able to align images, which contain minor image artifacts. The algorithm requires no a priori knowledge of the true image. The hierarchical design of the algorithm enhances robustness and accuracy, and saves computational costs. The proposed algorithm is decomposed into a fast, coarse, rigid registration step and a slower, but finer, nonrigid step. For the coarse registration, we use image pyramids, while for the second step, we combine a point-based registration with an elastic thin-plate spline interpolation. Accuracy tests, performed for 20 histological images obtained from human arteries, have shown that the error measure is acceptable, and that the image noise does not cause a problem. The associated convergence rate of the mean pixel displacement error during the rigid and nonrigid registrations is satisfying. The algorithm can be applied to various multicontrast elastic registration problems in medical imaging and may be extended to three dimensions. [ABSTRACT FROM AUTHOR]

Near infrared FT-Raman spectroscopy was applied for the determination of polymorphic forms in a number of commercial drug products containing the polymorphic drug compounds sorbitol, mannitol, famotidine, acemetacin, carbamazepine, meprobamate and phenylbutazone. The crystal forms present in the drug products were identified based on the position, intensity and shape of characteristic bands. Quantitative analysis of a mixture of two crystal forms of mannitol in a drug product was carried out using a partial least-squares method. In drug products containing meprobamate, sorbitol, and carbamazepine, the thermodynamically stable form was found exclusively, whereas metastable polymorphs were found in solid dosage forms of acemetacin, phenylbutazone, famotidine and mannitol. A mixture of two polymorphic forms of mannitol in Lipobay tablets was determined to consist of 30.8±3.8% of the metastable modification I. The simple sample preparation, the occurrence of sharp bands in the spectra as well as the high reproducibility and accuracy qualifies FT-Raman spectroscopy for the identification and quantification of crystal forms in drug products. The method is perfectly suited to meet the regulatory requirements of monitoring crystal forms during processing and storage and often succeeds in detecting the present crystal form in drug products even when the used excipients are not known. [Copyright &y& Elsevier]

Stimulated by excess levels of phosphorus, the attached, filamentous green alga Cladophora grows to nuisance proportions in Lake Michigan, one of the Laurentian Great Lakes. While nearshore waters impacted by local sources of the nutrient continue to support nuisance conditions, offshore waters have undergone oligotrophication in response to reductions in phosphorus loading and benthification of phosphorus cycling by invasive dreissenid mussels. A concept termed the Dual Challenge recognizes that implementation of more stringent phosphorus-loading objectives (to control Cladophora in the nearshore) stands in conflict with a foreseen need to mitigate oligotrophication in the offshore (to sustain a healthy fishery). Attention to this nearshore–offshore dynamic calls into play the role of cross-margin phosphorus transport in mediating both endmembers of the conflict. We applied a biophysical model simulating soluble reactive (SRP) and particulate (PP) phosphorus, mussel biokinetics, and cross-margin mass transport in addressing the Dual Challenge. Pre- and post-dreissenid monitoring results suggest that a reduction in offshore PP levels (food web nutrition) in excess of 40% (2.4 to 1.4 mgP·m−3) has driven oligotrophication and attendant food web dysfunction. Yet, in the absence of local sources, model-predicted nearshore SRP levels remain at or below those required to prevent nuisance growth. These findings indicate that there is a margin of ~1 mgP·m−3 over which offshore PP levels could be increased (to the benefit of the food web and the fishery) without hindering efforts to reduce nuisance algal growth through local source control. [ABSTRACT FROM AUTHOR]

Onondaga Lake, N.Y., experiences a marked annual dissolved oxygen depletion over the entire water column at fall turnover. Depletion occurs as a result of the entrainment of reduced substances that have accumulated in the lake's hypolimnion over the summer. Recovery (return to near-saturated conditions) occurs over a period of 3–4 weeks. Observations of dissolved oxygen (DO) levels during the recovery period of two years are used to calculate the reaeration coefficient ( K a,20= 0.22 d -1 in 1989, and 0.13 d -1 in 1990) and the liquid film transfer coefficient for oxygen ( K L,20= 2.64 m·d -1 in 1989, and 1.50 m·d -1 in 1990). Local wind measurements are used to develop an empirical relationship between wind speed ( U10, m·s -1) and K L,20: K L,20=α·U[sup β][sub 10], with α= 0.2; β= 1.0 for U10≤ 3.5 m·s -1 and α= 0.057; and β= 2.0 for U10> 3.5 m·s -1. Model output and field observations are compared with estimates generated using other published relationships. [ABSTRACT FROM AUTHOR]

Site suitability for egg development was assessed for walleyes Stizostedion vitreum in the Fox River, Wisconsin. Water chemistry at the sediment-water interface was compared with criteria for walleye egg hatch success (oxygen and hydrogen sulfide) and chronic toxicity (free ammonia). Reduced concentrations of dissolved oxygen and elevated concentrations of ammonianitrogen and hydrogen sulfide occurred above some sand and all soft muck substrates. The chemical oxygen demand (COD) of the surficial sediments was a useful surrogate variable for identifying the chemical suitability of spawning sites; locations with a surficial sediment COD less than 40 mg O2/g dry weight were considered suitable. A comprehensive surficial sediment survey of the lower Fox River below the DePere Dam showed that optimal walleye spawning habitat (gravel-cobble substrate) is rare (less than 3% of the area) and that 75% of the suboptimal (sand and muck) substrate is chemically unsuitable for walleye egg development. We conclude that successful natural reproduction by walleye in this portion of the lower Fox River is limited by the availability of suitable substrate. [ABSTRACT FROM AUTHOR]

Focuses on the factors regulating the seasonal growth and distribution of Ulothrix Zonata. Background on the species; Field observations of the seasonal and spatial distribution of the species; Impact of low temperature and high irradiance on net photosynthesis.

Differences in light penetration and light attenuating components and processes are documented along 112 km of the major (NE/SW) axis of Green Bay (Lake Michigan) during a three-day cruise (May 25-27, 1982). Measurements included diffuse attenuation of downwelling irradiance (k [ABSTRACT FROM AUTHOR]

The emerging shift in Great Lakes management from offshore to nearshore waters will require attention to complexities of coastal hydrodynamics and biogeochemical transformations. Emphasizing hydrodynamics, this work resolves transport processes in quantifying discharge plume and pollutant of concern (POC) footprint dimensions, the latter being the portion of the plume where water quality standards are not met. A generic approach, isolated from pollutant-specific biokinetics, provides first-approximation estimates of the footprint area. A high-resolution, linked hydrodynamic-tracer model is applied at a site in the Greater Toronto Area on Lake Ontario. Model results agree with observed meteorological and hydrodynamic conditions and satisfactorily simulate plume dimensions. Footprints are examined in the context of guidelines for regulatory mixing zone size and attendant loss of beneficial use. We demonstrate that the ratio of the water quality standard to the POC concentration at discharge is a key determinant of footprint dimensions. Footprint size for traditional pollutants (ammonia, total phosphorus) meets regulatory guidelines; however, that for soluble reactive phosphorus, a presently unattended pollutant, is ~1–2 orders of magnitude larger. This suggests that it may be necessary to upgrade treatment technologies to maintain consistency with regulatory guidelines and mitigate manifestations of the eutrophication-related soluble reactive phosphorus POC. [ABSTRACT FROM AUTHOR]

When analysing past excavations, the possible lack of information on stratigraphy of small finds can lead to difficulties in dating features of settlements such as building periods or destruction layers. While there can be many factors, the most common reasons are outdated excavation methods, lost written documentation or problems in storage. Studying the material from excavations at the so-called ›Gmeinerwiese‹ in Brigantium/Bregenz, Austria undertaken in 1974 suffered from a combination of these causes, which led to a lack of sound stratigraphical information. However, adapting techniques commonly used for numismatic analyses enabled the gathering of sufficient information to gain a better understanding of the sites’ building periods. Furthermore, an approximate date of the buildings’ destruction by fire could be obtained. Additionally, a second case study was undertaken using stratified and already analysed findings from Aguntum in Eastern Tyrol, Austria to verify the proposed methodology. The results are consistent with the stratigraphic evaluation, which indicates the functionality of this method. [ABSTRACT FROM AUTHOR]