330 research outputs found
Clinical anatomy and clinical significance of the cervical intervertebral foramen: a review
The aim of this paper is to summarise the knowledge about the anatomy of the cervical intervertebral foramen as a whole. Such reviews are rare in the literature. The intervertebral or neural foramen is the opening between the spinal canal and the extraspinal region. It is located between the vertebral pedicles at all spinal levels. A number of structures pass through the foramen: nerves, vessels and ligaments. We describe the bony borders and dimensions of the foramen, the adjacent ligaments, the arteries and veins passing through or neighbouring it, and the neural components. Many procedures are performed in the area of the cervical intervertebral foramen. Knowledge of the anatomy of the foramen is essential in order to operate to the area and to minimize iatrogenic injuries
Magnetization Relaxation and Collective Spin Excitations in Correlated Double--Exchange Ferromagnets
We study spin relaxation and dynamics of collective spin excitations in
correlated double--exchange ferromagnets. For this, we introduce an expansion
of the Green's functions equations of motion that treats non--perturbativerly
all correlations between a given number of spin and charge excitations and
becomes exact within a sub--space of states. Our method treats relaxation
beyond Fermi's Golden Rule while recovering previous variational results for
the spin--wave dispersion. We find that the momentum dependence of the
spin--wave dephasing rate changes qualitatively due to the on--site Coulomb
interaction, in a way that resembles experiment, and depends on its interplay
with the magnetic exchange interaction and itinerant spin lifetime. We show
that the collective spin relaxation and its dependence on the carrier
concentration depends sensitively on three--body correlations between a spin
excitation and a Fermi sea electron and hole. The above spin dynamics can be
controlled via the itinerant carrier population.Comment: 13 pages, 10 figures, published in Phys. Rev.
Predicting fraud in mobile money transfer using case-based reasoning
This paper proposes an improved CBR approach for the identification of money transfer fraud in Mobile Money Transfer (MMT) environments. Standard CBR capability is augmented by machine learning techniques to assign parameter weights in the sample dataset and automate k-value random selection in k-NN classification to improve CBR performance. The CBR system observes users’ transaction behaviour within the MMT service and tries to detect abnormal patterns in the transaction flows. To capture user behaviour effectively, the CBR system classifies the log information into five contexts and then combines them into a single dimension, instead of using the conventional approach where the transaction amount, time dimensions or features dimension are used individually. The applicability of the proposed augmented CBR system is evaluated using simulation data. From the results, both dimensions show good performance with the context of information weighted CBR system outperforming the individual features approach
Improved movie recommendations based on a hybrid feature combination method
Recommender systems help users find relevant items efficiently based on their interests and historical interactions with other users. They are beneficial to businesses by promoting the sale of products and to user by reducing the search burden. Recommender systems can be developed by employing different approaches, including collaborative filtering (CF), demographic filtering (DF), content-based filtering (CBF) and knowledge-based filtering (KBF). However, large amounts of data can produce recommendations that are limited in accuracy because of diversity and sparsity issues. In this paper, we propose a novel hybrid method that combines user–user CF with the attributes of DF to indicate the nearest users, and compare four classifiers against each other. This method has been developed through an investigation of ways to reduce the errors in rating predictions based on users’ past interactions, which leads to improved prediction accuracy in all four classification algorithms. We applied a feature combination method that improves the prediction accuracy and to test our approach, we ran an offline evaluation using the 1M MovieLens dataset, well-known evaluation metrics and comparisons between methods with the results validating our proposed method
A prefix brachial plexus with two trunks and one anterior cord
The brachial plexus presents a great variability in formation, division and branching pattern. Its variants are of immense importance during axillary and arm surgery and nerve blockade.
The current case highlights a unilateral atypical formation of brachial plexus, the so called prefix, in which the C4 root contributed a large branch to the superior trunk and further anastomosis with the inferior trunk. Thus, the prefix or high brachial plexus consisted of a superior and inferior trunk and one anterior cord.
Coexisting neural and arterial variations are also discussed in relation to the data literature
Concurrent lumbosacral and sacrococcygeal fusion: a rare aetiology of low back pain and coccygodynia?
Sacrum is a triangular bone placed in the base of the spine and formed by the synostosis of five sacral vertebrae (S1–S5). Its upper part is connected with the inferior surface of the body of L5 vertebra forming the lumbosacral joint, while its lower part is connected with the base of the coccyx forming the sacrococcygeal symphysis, an amphiarthrodial joint. The existence of four pairs of sacral foramina in both anterior and posterior surface of the sacrum is the most common anatomy. Nevertheless, supernumerary sacral foramina are possible to be created by the synostosis of lumbosacral joint or sacrococcygeal symphysis. We present a case of an osseous cadaveric specimen of the sacrum belonging to a 79-year-old Caucasian woman. A rare variation of the anatomy of the sacrum is reported; in which, the simultaneous fusion of the sacrum with both the L5 vertebra and the coccyx has created six pairs of sacral foramina. This variation should be taken into serious consideration, especially in the domain of radiology, neurosurgery, orthopaedics and spine surgery, because low back pain, coccygodynia and other neurological symptoms may emerge due to mechanical compression. (Folia Morphol 2018; 77, 2: 397–399
Butterfly vertebra. A case report and a short review of the literature
A butterfly vertebra is a rare congenital anomaly, encountered as isolated finding or as part of syndromic diseases. We report a case of a 40-year- old female presenting with low back pain and sciatica due to ‘butterfly’ dysplasia of the first sacral vertebra. This novel case includes posterolateral displacement of the completely separated hemivertebrae, causing left lateral recess stenosis and compression of S1 nerve root. Additionally, we conducted a short review of the literature. Few cases are reported in literature. Only one refers to a sacral vertebra. There is no previous case of a butterfly vertebra that accounts for narrowing of the lateral recess and associated radiculopath
Is BMI alone a sufficient outcome to evaluate interventions for child obesity?
BACKGROUND: BMI is often used to evaluate the effectiveness of childhood obesity interventions, but such interventions may have additional benefits independent of effects on adiposity. We investigated whether benefits to health outcomes following the Mind, Exercise, Nutrition…Do It! (MEND) childhood obesity intervention were independent of or associated with changes in zBMI.
METHODS: A total of 79 obese children were measured at baseline; 71 and 42 participants were followed-up at 6 and 12 months respectively, and split into four groups depending on magnitude of change in zBMI. Differences between groups for waist circumference, cardiovascular fitness, physical and sedentary activities, and self-esteem were investigated.
RESULTS: Apart from waist circumference and its z-score, there were no differences or trends across zBMI subgroups for any outcome. Independent of the degree of zBMI change, benefits in several parameters were observed in children participating in this obesity intervention.
CONCLUSION: We concluded that isolating a single parameter like zBMI change and neglecting other important outcomes is restrictive and may undermine the evaluation of childhood obesity intervention effectiveness
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