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This study addresses the problem of arriving at transitive perfect colorings of a symmetrical pattern {\cal P} consisting of disjoint congruent symmetric motifs. The pattern {\cal P} has local symmetries that are not necessarily contained in its global symmetry group G. The usual approach in color symmetry theory is to arrive at perfect colorings of {\cal P} ignoring local symmetries and considering only elements of G. A framework is presented to systematically arrive at what Roth [Geom. Dedicata (1984), 17, 99-108] defined as a coordinated coloring of {\cal P}, a coloring that is perfect and transitive under G, satisfying the condition that the coloring of a given motif is also perfect and transitive under its symmetry group. Moreover, in the coloring of {\cal P}, the symmetry of {\cal P} that is both a global and local symmetry, effects the same permutation of the colors used to color {\cal P} and the corresponding motif, respectively.
Taiwanocantharis thibetanomima (Wittmer, 1997) is redefined and its type series is clarified. Three new speciesare described and illustrated, Taiwanocantharis wittmeri sp. n. (CHINA: Yunnan), Taiwanocantharis adentata sp. n. (CHINA: Gansu, Sichuan) and Taiwanocantharis parasatoi sp. n. (CHINA: Guangxi). Taiwanocantharis gansosichuana (Kazantsev, 2010) is synonymized with Taiwanocantharis drahuska (Švihla, 2004). Taiwanocantharis dedicata (Švihla, 2005) and Taiwanocantharis malaisei (Wittmer, 1989) are recorded to China for the first time. A key to the species of the Taiwanocantharis thibetana species-group is provided.
This paper presents the results obtained in job evaluation of an organization working in the airport logistics. The sector is characterized by different activities that determine many types of musculoskeletal disorder and is marked by lack of knowledge of the accident prevention and health conditions at work. To analyze the workstations we have used video recordings, photographs and test through a dynamometer to determine the force applied during the pushing and pulling phase. In a lot of workstations were unacceptable NIOSH index due to a range of factors such as incorrect conformation of the workstations, the frequency and weight of loads handled, the heights of picking and unloading. Design solution have been studied and verified to reduce or eliminate the problems.
We investigated the role of an experimental surface coil for low field (0.2 T) MRI of prostatic gland carcinoma; the study was performed comparing MRI with US findings and with bioptic and pathologic results. To this purpose, 16 patients with prostatic cancer suspected at US and demonstrated with US-guided biopsy, were examined with low intensity field (0.2 T) MRI performed with a dedicated saddle-shaped coil and a body coil. This experimental surface coil with perineal application is used to study the prostatic gland with low field MR equipment where no transrectal probe is available. We analyzed the results of this study and found that, in all patients but one, the neoplastic lesions exhibited low signal intensity on T2-weighted images, while the normal gland was hyperintense. Six patients underwent radical prostatectomy and diagnostic imaging findings were correlated with pathologic findings obtained with whole mount specimens and serial histologic slides. The number of tumor foci, their site and size, and stromal reaction were studied on T2-weighted images; the typical low signal intensity was absent in one of 16 patients, in which case the microscopic exam of pathologic specimens showed extensive tumor spread with infiltration of perineural lymphatic vessels, with neither nodular patterns nor stromal reactions. The correlation between MR findings and the whole mount specimens (n = 6) demonstrated MR underestimation of tumor spread. In our opinion, this technique is useful for the detection and characterization of prostatic lesions, in spite of the presence of isointense lesions and the risk of underestimating the disease, especially to the prostatic capsule. To conclude, the dedicated surface coil can improve the diagnostic accuracy of low field MRI.
Cardiogenic shock (CS) is a rare disease that needs a rapid and multiparameter diagnosis and a timely, aggressive and multidisciplinary goal-oriented treatment. Recently published epidemiological studies and registries underline how SC represents an infrequent clinical entity still burdened by high mortality rates, substantially unchanged over the years. Currently, only few patients with CS are treated with circulatory assistance in dedicated centers. Some consensus documents and expert recommendations emphasize the importance of early diagnosis of CS, immediate pharmacological support, and treatment of precipitating causes, and stress the need for hospitalization in high-volume intensive care centers. The aim of this review is to show the instructions for the creation of a SC network, emphasizing the necessary elements, in agreement with available resources and existing health regulations for giving the same care opportunities to all the patients.
MR Imaging was performed on 10 healthy volunteers and 86 patients, using a 0.5 T superconducting magnet and a dedicated coil to image both breasts simultaneously. The patients were selected by the presence of nodules at clinical examination. Final diagnoses were made either at histology--in the patients who underwent surgery--or at cytology, with fine needle biopsy. The MR findings of the different breast diseases are discussed. In spite of an improved spatial resolution and of a very good natural contrast between different tissues, MR Imaging does not allow a satisfactory characterization of the lesions; its use is thus limited to the staging of cancers which need a better therapeutic planning.
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Labyrinth fractals are self-similar dendrites in the unit square that are defined with the help of a labyrinth set or a labyrinth pattern. In the case when the fractal is generated by a horizontally and vertically blocked pattern, the arc between any two points in the fractal has infinite length (Cristea and Steinsky in Geom Dedicata 141(1):1-17, 2009; Proc Edinb Math Soc 54(2):329-344, 2011). In the case of mixed labyrinth fractals a sequence of labyrinth patterns is used in order to construct the dendrite. In the present article we focus on the length of the arcs between points of mixed labyrinth fractals. We show that, depending on the choice of the patterns in the sequence, both situations can occur: the arc between any two points of the fractal has finite length, or the arc between any two points of the fractal has infinite length. This is in stark contrast to the self-similar case.
Magnetic Resonance Imaging (MRI) is a useful tool for demonstrating muscle changes in patients with inflammatory myopathies. We investigated the diagnostic capabilities of low field (0.2 T) MRI with a dedicated coil in a series of patients with an unquestionable clinical diagnosis of inflammatory myopathy. Infiltrating processes or muscle swelling are depicted as low-signal areas on T1-weighted SE images and as high-signal areas on T2-weighted SE and short time inversion recovery (STIR) images. Fatty infiltration appears as a high-signal area within muscles on T1-weighted SE images. T2-weighted SE and STIR sequences are highly sensitive in demonstrating infiltrating processes or muscle swelling. The signal-to-noise ratio was higher on T2-weighted SE than on STIR images; on the other hand, fast STIR sequences can effectively reduce scan times. To conclude, low field MRI is a useful tool in the study of inflammatory myopathies thanks to its noninvasiveness and to the good depiction of muscle inflammation provided by T2-weighted SE and STIR images.
We report our preliminary clinical experience with three-dimensional ultrasound (3D US) in abdominal and small parts imaging, comparing the yield of 3D versus 2D US and through a literature review. We used a Tomtec Echo-Scan 3.1 connected to a Philips P 700 unit with a 3.5 MHz convex probe and to a Toshiba SSA-340 A (equipped with power Doppler) with a 3.5 MHz convex and a 7.5 MHz linear probes. The system consists of: a) a workstation (166 MHz Intel Pentium, 128 Mbytes RAM, 520 Mbytes hard disk, 1.3 Gbyte Magneto-Optical drive); b) a spatial location system (3D Freehand Scanning) whose sensor, attached to the probe, provides spatial coordinates for each US scan in an electromagnetic field created by a transmitter; the software can thus correctly stack 2D US images to make 3D reconstructions of anatomical structures. The technical steps are: 1) setting; 2) image acquisition; 3) image processing and 3D rendering using surface or volume modes; 4) image archiving. 2D US was performed on 50 subjects, namely 20 volunteers and 30 patients with different pathologic conditions and 3D reconstructions were obtained from the best US images. We evaluated which anatomical structures and pathologic conditions are best suited for 3D rendering. The best 3D images were obtained from anatomical structures and pathologic conditions with a liquid content (i.e., bladder and gallbladder; cysts), or those adjacent to them (i.e., uterus and prostate). Major limitations were encountered in the assessment of the parenchyma of liver, kidneys, pancreas, thyroid, testis and breast, due to intrinsic texture low contrast, while intraparenchymal liquid structures (i.e., vessels, urinary cavities) and structures surrounded by liquid (i.e., hydrocele, ascites) were better demonstrated. The system permits accurate spatial location, and therefore stacking, of each US scan; this provides good-quality 3D images with fewer artifacts. The system can be connected to any existing US unit and to many kinds of probes. Incorrect processing or rendering may worsen 3D image quality and thus anatomical reconstructions; other drawbacks may come from difficult stacking of reconstructed images or limited field of view. Our personal experience and the review of 3D US literature indicate that the system may be used for the following clinical applications: anatomical assessment of lesions for minimally invasive treatment; targeting areas of interest and adjacent structures during radiotherapy; lesion volume studies during therapy; 3D vascular mapping with power Doppler; 3D reconstructions by intraluminal approach; real-time 3D scanning for US guidance during minimally invasive procedures. Our preliminary experience suggests that technological progress will soon lead to a widespread use of 3D US and its applications.
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Let $G$ be a compact Lie group. We study a class of Hamiltonian $(G \times S^{1})$-manifolds decorated with a function $s$ with certain equivariance properties, under conditions on the $G$-action which we call of (semi-)linear type. In this context, a close analogue of hyperkähler reduction is defined, and our main result establishes surjectivity of an appropriate analogue of Kirwan's map. As a particular case, our setting includes a class of hyperkähler manifolds with trihamiltonian torus actions, to which our surjectivity result applies.
We construct complete Calabi-Yau metrics on non-compact manifolds that are smoothings of an initial complete intersection $V_0$ that is a Calabi-Yau cone, extending the work of Székelyhidi (2019). The constructed Calabi-Yau manifold has tangent cone at infinity given by $\mathbb{C} \times V_0$. This construction produces Calabi-Yau metrics with fibers having varying complex structures and possibly isolated singularities.
Median spaces are spaces in which for every three points the three intervals between them intersect at a single point. It is well known that rank-1 affine buildings are median spaces, but by a result of Haettel, higher rank buildings are not even coarse median. We define the notion of ``2-median space'', which roughly says that for every four points the minimal discs filling the four geodesic triangles they span intersect in a point or a geodesic segment. We show that CAT(0) Euclidean polygonal complexes, and in particular rank-2 affine buildings, are 2-median. In the appendix, we recover a special case of a result of Stadler of a Fary-Milnor type theorem and show in elementary tools that a minimal disc filling a geodesic triangle is injective.
What if time doesn't actually exist until something changes。 Scientists at the University of Birmingham created a tiny "mini universe" using 24,000 ultracold atoms and showed that the flow of time can emerge naturally from changes inside a quantum system, without relying on any external clock