136 research outputs found
Spondylolisthesis on bilateral pedicle stress fracture in the lumbar spine: A case study
AbstractWe report the clinical case of a 54-year-old woman presenting radicular low back pain on the right side of L4 associated to spondylolisthesis on L4-L5, without any notion of trauma or spine surgery. Furthermore this patient is regularly seen for benign rheumatoid polyarthritis complicated by steroid-induced osteoporosis. A preventive treatment was implanted with good results on pain improvement and functional capacities. For pedicle fractures the literature review reports several different etiologies: spontaneous fractures, hereditary fractures or stress-related fractures. There was a discussion on the various treatments available and in this case of spondylolisthesis on pedicle fracture a conservative treatment was implemented similar to the one for isthmic spondylolisthesis. It yielded satisfying results
A note on anti-coordination and social interactions
This note confirms a conjecture of [Bramoull\'{e}, Anti-coordination and
social interactions, Games and Economic Behavior, 58, 2007: 30-49]. The
problem, which we name the maximum independent cut problem, is a restricted
version of the MAX-CUT problem, requiring one side of the cut to be an
independent set. We show that the maximum independent cut problem does not
admit any polynomial time algorithm with approximation ratio better than
, where is the number of nodes, and arbitrarily
small, unless P=NP. For the rather special case where each node has a degree of
at most four, the problem is still MAXSNP-hard.Comment: 7 page
The relevance of late MSA mandibles on the emergence of modern morphology in Northern Africa
North Africa is a key area for understanding hominin population movements and the expansion of our species. It is home to the earliest currently known Homo sapiens (Jebel Irhoud) and several late Middle Stone Age (MSA) fossils, notably KĂ©bibat, Contrebandiers 1, Dar-es-Soltane II H5 and El Harhoura. Mostly referred to as âAterianâ they fill a gap in the North African fossil record between Jebel Irhoud and Iberomaurusians. We explore morphological continuity in this region by quantifying mandibular shape using 3D (semi)landmark geometric morphometric methods in a comparative framework of late Early and Middle Pleistocene hominins (nâ=â15), Neanderthals (nâ=â27) and H. sapiens (nâ=â145). We discovered a set of mixed features among late MSA fossils that is in line with an accretion of modern traits through time and an ongoing masticatory gracilization process. In Northern Africa, Aterians display similarities to Iberomaurusians and recent humans in the area as well as to the Tighenif and Thomas Quarry hominins, suggesting a greater time depth for regional continuity than previously assumed. The evidence we lay out for a long-term succession of hominins and humans emphasizes North Africaâs role as source area of the earliest H. sapiens
ComposiciĂłn quĂmica, estabilidad oxidativa y actividad antiproliferativa del extracto de hexano de semilla de Anethum graveolens (eneldo)
This study aimed to evaluate the physicochemical properties, chemical composition, and antiÂproliferative activity of the hexane extract of Anethum graveolens L. (dill) seeds using gas chromatography mass spectrometry (GC-MS). Two fractions, namely the lipid fraction (74%) and volatile fraction (26%), were detected. The extract content of the seeds was about 9.4% and the extract had a pleasant spicy aroma. Oleic acid (52%), cis-vaccenic acid (6.2%), linoleic acid (5.5%), and palmitic acid (3.3%) were the key fatty acids in the lipid fraction, while apiol (23%) and d-carvone (2.4%) were the major volatile components. Tocols (tocopherols and tocotrienols) were also detected in the A. Graveolens extract (155 mg/100 g) and b-tocopherol was identified as the major tocol (71%). Dill extract showed a high oxidative stability (induction time = 45.22 h). Furthermore, dill extract showed antiproliferative activity against breast cancer cell lines.Este estudio tuvo como objetivo evaluar las propiedades fisicoquĂÂmicas, la composiciĂłn quĂmica y la actividad antiproliferativa del extracto de hexano de semillas de Anethum graveolens L. (eneldo) mediante cromatografĂa de gases con espectrometrĂa de masas (GC-MS). Se detectaron dos fracciones, la fracciĂłn lipĂdica (74%) y la fracciĂłn volĂĄtil (26%). El contenido del extracto de las semiÂllas fue de aproximadamente 9,4% y el extracto tenĂa un agradable aroma picante. Los ĂĄcidos oleico (52%), cis-vaccĂ©nico (6,2%), linoleico (5,5%) y palmĂtico (3,3%) fueron los ĂĄcidos grasos clave en la fracciĂłn lipĂdica, mientras que el apiol (23%) y la d-carvona (2,4%) fueron los principales componentes volĂĄtiles. TambiĂ©n se detectaron tocoles (tocoferoles y tocotrienoles) en el extracto de A. Graveolens (155 mg/100 g) y se identificĂł el ÎČ-tocoferol como el principal tocol (71%). El extracto de eneldo mostrĂł una alta estabilidad oxidativa (tiempo de inducciĂłn = 45,22 h). AdemĂĄs, el extracto de eneldo mostrĂł actividad antiproliferativa contra las lĂneas celulares de cĂĄncer de mama
Vector Bin Packing with Multiple-Choice
We consider a variant of bin packing called multiple-choice vector bin
packing. In this problem we are given a set of items, where each item can be
selected in one of several -dimensional incarnations. We are also given
bin types, each with its own cost and -dimensional size. Our goal is to pack
the items in a set of bins of minimum overall cost. The problem is motivated by
scheduling in networks with guaranteed quality of service (QoS), but due to its
general formulation it has many other applications as well. We present an
approximation algorithm that is guaranteed to produce a solution whose cost is
about times the optimum. For the running time to be polynomial we
require and . This extends previous results for vector
bin packing, in which each item has a single incarnation and there is only one
bin type. To obtain our result we also present a PTAS for the multiple-choice
version of multidimensional knapsack, where we are given only one bin and the
goal is to pack a maximum weight set of (incarnations of) items in that bin
Parameterized Inapproximability of Independent Set in -Free Graphs
We study the Independent Set (IS) problem in -free graphs, i.e., graphs
excluding some fixed graph as an induced subgraph. We prove several
inapproximability results both for polynomial-time and parameterized
algorithms.
Halld\'orsson [SODA 1995] showed that for every IS has a
polynomial-time -approximation in -free
graphs. We extend this result by showing that -free graphs admit a
polynomial-time -approximation, where is the
size of a maximum independent set in . Furthermore, we complement the result
of Halld\'orsson by showing that for some there is
no polynomial-time -approximation for these graphs, unless NP = ZPP.
Bonnet et al. [IPEC 2018] showed that IS parameterized by the size of the
independent set is W[1]-hard on graphs which do not contain (1) a cycle of
constant length at least , (2) the star , and (3) any tree with two
vertices of degree at least at constant distance.
We strengthen this result by proving three inapproximability results under
different complexity assumptions for almost the same class of graphs (we weaken
condition (2) that does not contain ). First, under the ETH, there
is no algorithm for any computable function .
Then, under the deterministic Gap-ETH, there is a constant such that
no -approximation can be computed in time. Also,
under the stronger randomized Gap-ETH there is no such approximation algorithm
with runtime .
Finally, we consider the parameterization by the excluded graph , and show
that under the ETH, IS has no algorithm in -free graphs
and under Gap-ETH there is no -approximation for -free
graphs with runtime .Comment: Preliminary version of the paper in WG 2020 proceeding
Spectre multifractal : Applications aux images médicales
Dans cet article, nous proposons une mĂ©thode puissante pour la caractĂ©risation et la segmentation des images mĂ©dicales basĂ©e sur la gĂ©omĂ©trie fractale. Le principe de cette mĂ©thode en analyse dâimages est justifiĂ© par lâauto-similaritĂ© dâune texture sur une rĂ©solution finie qui repose principalement sur lâestimation dâattributs fractals. Diverses mĂ©thodes ont Ă©tĂ© proposĂ©es pour estimer la dimension fractale. Dans ce travail nous dĂ©veloppons une mĂ©thode basĂ©e sur le spectre multifractal de Hausdorff pour caractĂ©riser des images mĂ©dicales CT-Scan. Les rĂ©sultats obtenus dĂ©montrent lâintĂ©rĂȘt de cette gĂ©omĂ©trie et son adaptabilitĂ© pour caractĂ©riser les altĂ©rations des textures osseuses saines et ostĂ©oporotiques
Post-treatment follow-up study of abdominal cystic echinococcosis in Tibetan communities of northwest Sichuan Province, China
Background: Human cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, with the liver as the
most frequently affected organ, is known to be highly endemic in Tibetan communities of northwest Sichuan Province.
Antiparasitic treatment with albendazole remains the primary choice for the great majority of patients in this resource-poor
remote area, though surgery is the most common approach for CE therapy that has the potential to remove cysts and lead
to complete cure. The current prospective study aimed to assess the effectiveness of community based use of cyclic
albendazole treatment in Tibetan CE cases, and concurrently monitor the changes of serum specific antibody levels during
treatment.
Methodology/Principal Findings: Ultrasonography was applied for diagnosis and follow-up of CE cases after cyclic
albendazole treatment in Tibetan communities of Sichuan Province during 2006 to 2008, and serum specific IgG antibody
levels against Echinococcus granulosus recombinant antigen B in ELISA was concurrently monitored in these cases. A total of
196 CE cases were identified by ultrasound, of which 37 (18.9%) showed evidence of spontaneous healing/involution of
hepatic cyst(s) with CE4 or CE5 presentations. Of 49 enrolled CE cases for treatment follow-up, 32.7% (16) were considered
to be cured based on B-ultrasound after 6 months to 30 months regular albendazole treatment, 49.0% (24) were improved,
14.3% (7) remained unchanged, and 4.1% (2) became aggravated. In general, patients with CE2 type cysts (daughter cysts
present) needed a longer treatment course for cure (26.4 months), compared to cases with CE1 (univesicular cysts) (20.4
months) or CE3 type (detached cyst membrane or partial degeneration of daughter cysts) (9 months). In addition, the
curative duration was longer in patients with large (.10 cm) cysts (22.3 months), compared to cases with medium (5â
10 cm) cysts (17.3 months) or patients with small (,5 cm) cysts (6 months). At diagnosis, seven (53.8%) of 13 cases with CE1
type cysts without any previous intervention showed negative specific IgG antibody response to E. granulosus recombinant
antigen B (rAgB). However, following 3 months to 18 months albendazole therapy, six of these 7 initially seronegative CE1
cases sero-converted to be specific IgG antibody positive, and concurrently ultrasound scan showed that cysts changed to
CE3a from CE1 type in all the six CE cases. Two major profiles of serum specific IgG antibody dynamics during albendazole
treatment were apparent in CE cases: (i) presenting as initial elevation followed by subsequent decline, or (ii) a persistent
decline. Despite a decline, however, specific antibody levels remained positive in most improved or cured CE cases.
Conclusions: This was the first attempt to follow up community-screened cystic echinococcosis patients after albendazole
therapy using ultrasonography and serology in an endemic Tibetan region. Cyclic albendazole treatment proved to be
effective in the great majority of CE cases in this resource-poor area, but periodic abdominal ultrasound examination was
necessary to guide appropriate treatment. Oral albendazole for over 18 months was more likely to result in CE cure. Poor
drug compliance resulted in less good outcomes. Serology with recombinant antigen B could provide additional limited
information about the effectiveness of albendazole in CE cases. Post-treatment positive specific IgG antibody
seroconversion, in initially seronegative, CE1 patients was considered a good indication for positive therapeutic efficacy
of albendazole
On cycle transversals and their connected variants in the absence of a small linear forest.
A graph is H-free if it contains no induced subgraph isomorphic to H. We prove new complexity results for the two classical cycle transversal problems Feedback Vertex Set and Odd Cycle Transversal by showing that they can be solved in polynomial time for (sP1+P3) -free graphs for every integer sâ„1 . We show the same result for the variants Connected Feedback Vertex Set and Connected Odd Cycle Transversal. For the latter two problems we also prove that they are polynomial-time solvable for cographs; this was known already for Feedback Vertex Set and Odd Cycle Transversal
Using multimedia and peer assessment to promote collaborative e-learning
Collaborative e-learning is increasingly appealing as a pedagogical approach that can positively affect student learning. We propose a didactical model that integrates multimedia with collaborative tools and peer assessment to foster collaborative e-learning. In this paper, we explain it and present the results of its application to the âInternational Seminars on Materials Scienceâ online course. The proposed didactical model consists of five educational activities. In the first three, students review the multimedia resources proposed by the teacher in collaboration with their classmates. Then, in the last two activities, they create their own multimedia resources and assess those created by their classmates. These activities foster communication and collaboration among students and their ability to use and create multimedia resources. Our purpose is to encourage the creativity, motivation, and dynamism of the learning process for both teachers and students
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