We discuss a bi-objective two-stage assignment problem (BiTSAP) that aims at minimizing two objective functions: one comprising a nonlinear cost function defined explicitly in terms of assignment variables and the other a total completion time. A two-stage assignment problem deals with the optimal allocation of n jobs to n agents in two stages, where $n_1$ out of n jobs are primary jobs which constitute Stage-1 and the rest of the jobs are secondary jobs constituting Stage-2. The paper proposes an algorithm that seeks an optimal solution for a BiTSAP in terms of various efficient time-cost pairs. An algorithm for ranking all feasible assignments of a two-stage assignment problem in order of increasing total completion time is also presented. Theoretical justification and numerical illustrations are included to support the proposed algorithms.

Saimiri collinsi is used as an animal model in biotechnology research for conservation of species from the genus Saimiri. However, the development of biotechnologies depends on a proper knowledge of the sperm morphology to understand the basic aspects of sperm physiology, as potential male fertility depends on different cellular sperm structures. With this purpose, this study characterized the micromorphological and ultrastructural characteristics of squirrel monkeys (Saimiri collinsi) sperm using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM electromyography revealed that a normal Saimiri collinsi sperm measures 71.7 ± 0.7 μm with lateral tail insertion, a paddle-shaped flattened head and an acrosome occupying most of the head. TEM also showed that the middle piece is characterized by a central 9 + 2 microtubule axoneme surrounded by nine dense fibres, and that the mitochondria were juxtaposed, forming the mitochondrial sheath. Here we provide the first micromorphological and ultrastructure description of S. collinsi sperm.

A scanning tunneling microscope (STM) requires precise control of the tip–sample distance to maintain a constant set-point tunneling current. Typically, the tip–sample distance is controlled through the use of a control algorithm. The control algorithm takes in the measured tunneling current and returns a correction to the tip–sample distance in order to achieve and maintain the set-point value for tunneling current. We have developed an STM simulator to test the accuracy and performance of four control algorithms. The operation and effectiveness of these control algorithms are evaluated.

Spectral measurements of sunlight reflected from planetary surfaces, when correlated with experimental visible-near-infrared spectra of rock-forming minerals, are being used to detect transition metal cations, to identify constituent minerals, and to determine modal mineralogies of regoliths on terrestrial planets. Such remote-sensed reflectance spectra measured through earth-based telescopes may have absorption bands in the one micron and two micron wavelength regions which originate from crystal field transitions within Fe2+ ions. Pyroxenes with Fe2+ in M2 positions dominate the spectra, and the resulting 1 μm versus 2 µm spectral determinative curve is used to identify compositions and structure-types of pyroxenes on surfaces of the Moon, Mercury, and asteroids, after correcting for experimentally-determined temperature-shifts of peak positions. Olivines and Fe2+-bearing plagioclase feldspars also give diagnostic peaks in the 1 µm region, while tetrahedral Fe2+ in glasses absorb in the 2 µm region as well. Opaque ilmenite, spinel and metallic iron phases mask all of these Fe2+ spectral features. Laboratory studies of mixed-mineral assemblages enable coexisting Fe2+ phases to be identified in remote-sensed reflectance spectra of regoliths. Thus, noritic rocks in the lunar highlands, troctolites in central peaks of impact craters such as Copernicus, and high-Ti and low-Ti mare basalts have been mapped on the Moon's surface by telescopic reflectance spectroscopy. The Venusian atmosphere prevents remote-sensed spectral measurements of its surface mineralogy, while atmospheric CO2 and ferric-bearing materials in the regolith on Mars interfere with pyroxene characterization in bright- and dark-region spectra. Reflectance spectral measurements of several meteorite types, including specimens from Antarctica, are consistent with a lunar highland origin for achondrite ALHA 81005 and a martian origin for shergottite EETA 79001, although source regions may not be outermost surfaces of the Moon and Mars. Correlations with asteroid reflectance spectra suggest that Vesta is the source of basaltic achondrites, while wide ranges of olivine/pyroxene ratios are inconsistent with an ordinary-chondrite surface composition of many asteroids. Visible-near-infrared spectrometers are destined for instrument payloads in future spacecraft missions to neighbouring solar system bodies.

Sample preparation and imaging techniques for scanning electron microscopy (SEM) of dehydrated dental samples can hinder the structural analyses. This study qualitatively evaluated images obtained with two different protocols of SEM preparation and analysis to assess the dentine adhesive interface. The crown and root dentine of 12 bovine incisors were subjected to cementation with the resin cement RelyX U100 or RelyX ARC/SBMP (n = 6). After storage for 7 days in a moist environment at 37 ± 1°C, the dentine samples were dehydrated in an ascending alcohol series, and three specimens from each group were coated with gold or carbon and examined in a high-vacuum (JEOL JSM—6360LV, 10 kV) or low-vacuum (FEI Quanta 200F, 15–30 kV) microscope. Images were obtained at magnifications between 50 and 2,000×, but with different working distances. The use of high vacuum for carbon and gold coating and SEM visualization led to cracks in the samples. A small number of cracks can be described in the specimens subjected to the low-vacuum technique. The protocol for SEM imaging in low vacuum was considered more appropriate for preservation of the integrity of the evaluated structures.

The “LEXT” confocal laser scanning microscope has been used for the three-dimensional (3D) imaging of the surface of specimens, especially in materials science fields, by the penetration of near-infrared (NIR) light without mechanical cutting, deposition, or other specimen pretreatment. Noninvasive investigation of various biological tissues such as human spinal dura mater, rat aorta, and cornea without the dehydration process was successfully carried out with the “LEXT,” in order to access both surface and internal topographic images of the biological structures at a good status of the wet tissue such as in vivo, especially in measuring tissue thickness. The confocal NIR laser microscopy offers the viable means to visualize tissue architecture and its thickness in microdomain to integrate 3D images efficiently. We believe that the “LEXT” has a good application for biological researchers to study biomaterials, and it would be useful as a diagnostic tool in the near future.

The best means to utilize X-ray computed tomography (CT) and ultrasound to predict carcass lean, fat and bone weights in vivo in terminal sire sheep were tested. Data on 160 lambs from three breeds were considered: 50 Suffolk males, 50 Suffolk females, 40 Texel males and 20 Charollais males. One-fifth of the lambs within each breed and sex group were slaughtered at each of 14, 18 and 22 weeks of age and the remaining two-fifths at 26 weeks. Carcasses were dissected into lean, fat and bone weights. Prior to slaughter all lambs were CT scanned, with cross-sectional scans taken at seven sites along the body (ischium, hip, mid shaft of femur, 2nd and 5th lumbar vertebrae and 6th and 8th thoracic vertebrae), and ultrasound scanned at the 3rd lumbar vertebra and 13th rib.A set of three CT scans that reliably predicted carcass lean, fat and bone weights was identified which included a scan in each of the three main carcass regions: ischium in the hind leg, 5th lumbar vertebra in the loin and 8th thoracic vertebra in the shoulder. Breed and sex affected the intercepts of the prediction equations but not their slopes. Therefore, a minimal set of equations is likely to be sufficient to predict tissue weights, at least within terminal sire sheep breeds. Equations derived showed high degrees of fit to the data with R2 values of 0·924, 0·978 and 0·830 for lean, fat and bone weights, respectively, when predicted using CT alone, and 0·589 and 0·857 for lean and fat weights, respectively, when predicted using ultrasound alone. Using live weight in addition to CT information only improved prediction accuracy slightly for lean (0·966) and fat (0·986) although more substantially for bone (0·925). Where live and tissue weights are considered contemporaneously in genetic evaluations, excluding live weight from prediction may therefore be preferable to avoid colinearity among weight measures.

The aim of this study was to analyse the tissue surrounding prematurely extruded ventilation tubes (grommets). Thirty-one ventilation tubes, including 21 Shah and six Shepherd tubes, that had been extruded naturally into the ear canal were examined. After formalin fixation, material adhering to the tubes was retrieved and processed to paraffin wax. Five tubes were processed for scanning electron microscope (SEM) analysis. Sections were stained using histochemical methods for collagen, keratin and keratohyaline. In addition, the presence of collagen (type I and III), keratin, vimentin, fibronectin, tenascin, factor VIII-related antigen, CD31 and CD45 was tested for by immunohistochemistry. Results showed that all specimens consisted of an acellular fibrous material, oriented in concentric rings parallel to the tube surface that was often associated with small collections of CD45+ inflammatory cells. Two specimens contained collagen that was detectable by histochemical and immunohistological methods. Twelve specimens contained identifiable desquamated epithelial cells containing keratin and keratohyaline. Only one specimen stained positively for connective tissue markers (vimentin, fibrous fibronectin, tenascin) or showed the presence of vascular epithelium. SEM revealed adherent clusters or sheets of plate-like structures, consistent with the presence of epithelial squames, on three of the five ventilation tubes examined. It is concluded that tissue retained on extruded grommets consists of orthokeratinitizing epithelium infiltrated by inflammatory cells, a finding that is consistent with the theory that tube extrusion occurs as a result of squamous epithelial proliferation, medial migration, differentiation and desquamation. epithelial cells containing keratin and keratohyaline. Only one specimen stained positively for connective tissue markers (vimentin, fibrous fibronectin, tenascin) or showed the presence of vascular epithelium. SEM revealed adherent clusters or sheets of plate-like structures, consistent with the presence of epithelial squames, on three of the five ventilation tubes examined. It is concluded that issue retained on extruded grommets consists of orthokeratinitizing epithelium infiltrated by inflammatory cells, a finding that is consistent with the theory that tube extrusion occurs as a result of squamos epithelial proliferation, medial migration, differentiation and desquamation.

The kinetics of a thin-film, solid-state reaction were investigated in the spinel-forming oxide system Fe2O3/MgO. In this study, epitactic thin films of Fe2O3 (α, or corundum, structure) were deposited on (001)-oriented MgO using pulsed-laser deposition (PLD). The resulting diffusion couples were then reacted at elevated temperatures in air to induce the reaction between the thin-film and bulk substrate to form the spinel, MgFe2O4. Both the as-deposited and reacted diffusion couples were characterized using low-voltage scanning and transmission electron microscopy. These techniques allow the kinetics of the reaction and the structural properties of the spinel to be investigated.

Récemment encore, les méthodes d'imagerie proposées dans le diagnostic précoce des lésions d'irradiation localisée semblaient faire défaut. La tomodensitométrie et la scintigraphie augallium-67, examens de pratique courante, ont été étudiées dans un modèle expérimental d'irradiation localisée, développé après plusieurs accidents de surexposition. Douze lapins ont étéirradiés par une source d'Iridium-192, avec une dose unique de 120 Gy à la peau délivrée en regard du muscle iliospinal droit, au niveau de la cinquième vertèbre lombaire. Des modificationsprécoces ont été observées dans ce modèle expérimental par ces 2 méthodes d'imagerie in vivo, avec un hyperfixation scintigraphique en regard de la lésion d'irradiation dès le troisième jouraprès irradiation et des anomalies tomodensitométriques évolutives au cours du premier mois, avec des résultats homogènes dans toute la cohorte. Ces 2 techniques pourraient contribuer à undiagnostic précoce et une évaluation pronostique des lésions d'irradiation aiguë. Un suivi portant sur une durée de 18 à 24 mois, permettant d'aborder les processus tardifs, classiquementcaractérisés par des délabrements musculaires et le développement d'une sclérose atrophique.

The dependence of the In-incorporation efficiency and the optical properties of MOVPE-grown GaInN/GaN-heterostructures on various growth parameters has been investigated. A significant improvement of the In-incorporation rate could be obtained by increasing the growth rate and reducing the H2-partial pressure in the MOVPE reactor. However, GaInN layers with a high In-content typically show an additional low energy photoluminescence peak, whose distance to the band-edge increases with increasing In-content. For GaInN/GaN quantum wells with an In-content of approximately 12%, an increase of the well thickness is accompanied by a significant line broadening and a large increase of the Stokes shift between the emission peak and the band edge determined by photothermal deflection spectroscopy. With a further increase of the thickness of the GaInN layer, a second GaInN-correlated emission peak emerges. To elucidate the nature of these optical transitions, power-dependent as well as time-resolved photoluminescence measurements have been performed and compared to the results of scanning transmission electron microscopy.

We present a novel combined atomic force microscope (AFM) and confocal laser scanning microscope (CLSM). The sample is supported from the side by a boom from a piezo tube scanner, allowing top and bottom access to the sample. The sample is scanned above an inverted microscope objective with a fixed optical path for fluorescent CLSM imaging. An AFM positioned directly above the sample simultaneously measures surface topography. The piezo tube scanner is angled, placing its center of scan curvature directly above the microscope objective. This geometry allows flat scans up to 300 μm on a side. Because the sample is scanned, the AFM and CLSM images are acquired in direct registration.

This is the first report of the application of a new examination technique for the assessment of cellular activity during bone resorption in chronic suppurative otitis media (CSOM). A total of nineteen incudes removed during the course of tympanomastoid surgery were studied (retraction pocket: 2; tubo-tympanic CSOM: 4; attico-antral CSOM: 13). The microscopic surface topography of each specimen was examined using the scanning electron microscopy (SEM), and the appearances are interpreted in terms of cortical cellular activity. The results suggest that the mechanism of ossicular erosion in CSOM is similar regardless of the exact type of disease. Extensively, pitted areas were seen in all specimens. These pits are morphologically indistinguishable from those characteristic of osteoclastic activity (Howship's lacunae). We conclude that in all causes the surface topography of eroded incudes is consistent with the activity of osteoclasts.

For point processes, such that the interarrival times of points are independently and identically distributed, let T(L, m) denote the time until at least points cluster within an interval of length at most L. Let τ (L, m) + 1 be the total number of points observed until the above happens. Simple approximations of Eτ (L, m) and ET(L, m) are derived, as well as lower and upper bounds for their value. Approximations to the variances are also given. In particular the Poisson, Bernoulli and compound Poisson processes are discussed in detail. Some numerical tables are included.