380 research outputs found
Morphological variation of carotid artery bifurcation level in digital angiography
Knowing of the level of carotid artery bifurcation (CB) is important for vascular surgery in the neck, radical neck dissections, carotid sinus baroreceptor stimulation, catheterisations, and aneurysms. The aim of this study was to determine the CB level in relation with the cervical vertebral levels, compare them on the right and the left sides, and investigate the relation of CB level with the length of neck. In this study, 100 conventional carotid angiographies were performed. The CB level was determined in relation with 10 different levels which were the levels of the cervical vertebrae and intervertebral disks, and the relation of CB level with the length of neck was investigated. The right and left CB levels of the patients were also determined, and compared. The highest level of CB was at the level of C2 vertebra, and the lowest level of CB was at the level of C6–C7 intervertebral disk in both male and female. When all patients were taken into consideration, CB level was most frequently seen at the level of C4–C5 (29%) on the right side, and at the level of C4 (26%) on the left side. The CB levels were not symmetrical in 10 female and 23 male. Knowing of the anatomical variations of CB level is important in surgical procedures. The anatomical differences must be taken into consideration since the neighbouring structures of CB change in case of variations. We believe that the results of this study will shed light to planning of all interventional methods concerning common carotid artery and its branches as well as surgery in the neck, and will help to minimise the complications
An Alternative Approach to the Fracture Toughness of Dual Phase Steels
In this study, the effects of ferrite morphology and of ferrite volume fraction on the mechanical properties and the fracture toughness values ( ) KIc of dual phase steels were investigated. The fracture toughness values were determined using an approach that was different from the standard one. A homogenization heat treatment was applied to the steels. Two different starting microstructures were then obtained by either the full annealing of or the quenching of the steels from austenite before applying intercritical annealing to the steels in the austenite region. After this process, dual phase steels with two types of morphology, coarse and fine, were obtained with 40, 20, and 10% ferrite volume fractions, depending on the starting microstructure. Tempered specimens with 10% ferrite exhibited improved fracture toughness values compared with those of the other steels.Исследуется влияние морфологии структуры феррита и его объемного содержания на
механические свойства и вязкость разрушения двухфазных сталей. Для определения значений
вязкости разрушения использовали не стандартный, а альтернативный подход. Стали подвергали гомогенизирующей термообработке. Путем полного отжига или закалки сталей из
аустенитного состояния до применения докритического отжига в аустенитной области
получены две различные исходные микроструктуры. Получены двухфазные стали с двумя
типами морфологии (крупно- и мелкозернистая) с 40-, 20- и 10%-ным объемным содержанием
феррита в зависимости от исходной микроструктуры. Отпущенные образцы с 10%-ным
объемным содержанием феррита имели более высокие значения вязкости разрушения по
сравнению с таковыми других образцов из этих сталейДосліджується вплив морфології структури фериту та його об’ємного вмісту
на механічні властивості і в’язкість руйнування двофазних сталей. Для визначення значень в’язкості руйнування використовували не стандартний, а альтернативний підхід. Сталі піддавали гомогенізуючій термообробці. Шляхом повного відпалу або загартування сталей з аустенітного стану до використання
докритичного відпалу в аустенітній області отримано дві різні початкові
мікроструктури. Отримано двофазні сталі з двома типами морфології (великоі дрібнозеренна) з 40-, 20- і 10%-ним об’ємним вмістом фериту в залежності
від початкової мікроструктури. Відпущені зразки з 10%-ним об’ємним вмістом фериту мали більш високі значення в’язкості руйнування порівняно з
такими інших зразків із цих сталей
A Study on the Yield Strength of bcc Latticed Metals and Alloys
Предложен математический подход, позволяющий теоретически прогнозировать зависимости предела текучести металлов и сплавов с ОЦК-кристаллической решеткой от температуры и скорости деформации. При этом величину предела текучести для произвольной скорости деформации можно рассчитать на основании экспериментальных данных, полученных для двух различных скоростей деформации.Запропоновано математичний підхід, що дозволяє теоретично прогнозувати залежність границі плинності металів і сплавів з ОЦК-кристалічною граткою від температури і швидкості деформації. При цьому величину границі плинності для довільної швидкості деформації можна розрахувати на основі експериментальних даних, отриманих для різних швидкостей деформації
Morphometric analysis of fossil bumble bees (Hymenoptera, Apidae, Bombini) reveals their taxonomic affinities
This work is licensed under a Creative Commons Attribution 4.0 International License.Bumble bees (Bombus spp.) are a widespread corbiculate lineage (Apinae: Corbiculata: Bombini), mostly found among temperate and alpine ecosystems. Approximately 260 species have been recognized and grouped recently into a simplified system of 15 subgenera. Most of the species are nest-building and primitively eusocial. Species of Bombus have been more intensely studied than any other lineages of bees with the exception of the honey bees. However, most bumble bee fossils are poorly described and documented, making their placement relative to other Bombus uncertain. A large portion of the known and presumed bumble bee fossils were re-examined in an attempt to better understand their affinities with extant Bombini. The taxonomic affinities of fossil specimens were re-assessed based on morphological features and previous descriptions, and for 13 specimens based on geometric morphometrics of forewing shape. None of the specimens coming from Eocene and Oligocene deposits were assigned within the contemporary shape space of any subgenus of Bombus. It is shown that Calyptapis florissantensis Cockerell, 1906 (Eocene-Oligocene boundary, Florissant shale, Colorado, USA) and Oligobombus cuspidatus Antropov, 2014 (Late Eocene, Bembridge Marls) likely belong to stem-group Bombini. Bombus anacolus Zhang, 1994, B. dilectus Zhang, 1994, B. luianus Zhang, 1990 (Middle Miocene, Shanwang Formation), as well as B. vetustus Rasnitsyn & Michener, 1991 (Miocene, Botchi Formation) are considered as species inquirenda. In the Miocene, affinities of fossils with derived subgenera of Bombus s. l. increased, and some are included in the shape space of contemporary subgenera: Cullumanobombus (i.e., B. pristinus Unger, 1867, B. randeckensis Wappler & Engel, 2012, and B. trophonius Prokop, Dehon, Michez & Engel, 2017), Melanobombus (i.e., B. cerdanyensis Dehon, De Meulemeester & Engel, 2014), and Mendacibombus (i.e., B. beskonakensis (Nel & Petrulevičius, 2003), new combination), agreeing with previous estimates of diversification
Boosting Object Recognition in Point Clouds by Saliency Detection
Object recognition in 3D point clouds is a challenging task, mainly when time
is an important factor to deal with, such as in industrial applications. Local
descriptors are an amenable choice whenever the 6 DoF pose of recognized
objects should also be estimated. However, the pipeline for this kind of
descriptors is highly time-consuming. In this work, we propose an update to the
traditional pipeline, by adding a preliminary filtering stage referred to as
saliency boost. We perform tests on a standard object recognition benchmark by
considering four keypoint detectors and four local descriptors, in order to
compare time and recognition performance between the traditional pipeline and
the boosted one. Results on time show that the boosted pipeline could turn out
up to 5 times faster, with the recognition rate improving in most of the cases
and exhibiting only a slight decrease in the others. These results suggest that
the boosted pipeline can speed-up processing time substantially with limited
impacts or even benefits in recognition accuracy.Comment: International Conference on Image Analysis and Processing (ICIAP)
201
The effect of supersymmetric CP phases on Chargino-Pair Production via Drell-Yan Process at the LHC
We compute the rates for pp annihilation into chargino-pairs via Drell-Yan
process taking into account the effects of supersymmetric soft phases, at
proton-proton collider. In particular, the phase of the mu parameter gains
direct accessibility via the production of dissimilar charginos. The phases of
the trilinear soft masses do not have a significant effect on the cross
sections.Comment: 24 pages, 7 figure
Bounds on the dipole moments of the tau-neutrino via the process in a 331 model
We obtain limits on the anomalous magnetic and electric dipole moments of the
through the reaction
and in the framework of a 331 model. We consider initial-state radiation, and
neglect and photon exchange diagrams. The results are based on the data
reported by the L3 Collaboration at LEP, and compare favorably with the limits
obtained in other models, complementing previous studies on the dipole moments.Comment: 13 pages, 4 figures, to be published in The European Physical J C.
arXiv admin note: substantial text overlap with arXiv:hep-ph/060527
Antibiotics resistance of Stenotrophomonas maltophilia strains isolated from various clinical specimens.
Background: A limited number of antibiotics are recommended for the
therapy of Stenotrophomonas maltophilia infections due to therapy
difficulties caused by its numerous mechanisms of resistance.
Objectives: In this study conducted over a period of approximately 5
years we aimed to determine resistance rates of S. maltphilia based on
drug classification recommended by Clinical and Laboratory Standards
Institute. Methods: A total of 118 S. maltphilia strains isolated from
various clinical specimens between January 2006 and June 2012 were
included in the study. BD Phoenixautomated microbiology system (Becton
Dickinson, USA) was utilized for species level identification and
antibiotic susceptibility testing. Results: Sixty seven of S.
maltphilia strains were isolated from tracheal aspirate isolates, 17
from blood, 10 from sputum, 10 from wound and 14 from other clinical
specimens. Levofloxacin was found to be the most effective antibiotic
against S. maltphilia strains with resistance rate of 7.6%. The
resistance rates to other antibiotics were as follows: chloramphenicol
18.2%, trimethoprim-sulfamethoxazole 20.3% and ceftazidime 72%.
Conclusion: The study revealed that S. maltphilia is resistant to many
antibiotics. The treatment of infections caused by S. maltphilia should
be preferred primarily as levofloxacin, chloramphenicol, and TMP-SXT,
respectively
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