1,025 research outputs found
Pfaffian representations of cubic surfaces
Let K be a field of characteristic zero. We describe an algorithm which
requires a homogeneous polynomial F of degree three in K[x_0,x_1,x_2,x_3] and a
zero A of F in P^3_K and ensures a linear pfaffian representation of V(F) with
entries in K[x_0,x_1,x_2,x_3], under mild assumptions on F and A. We use this
result to give an explicit construction of (and to prove the existence of) a
linear pfaffian representation of V(F), with entries in K'[x_0,x_1,x_2,x_3],
being K' an algebraic extension of K of degree at most six. An explicit example
of such a construction is given.Comment: 17 pages. Expanded with some remarks. Published with minor
corrections in Geom. Dedicat
The Jacobian Conjecture 2n implies the Dixmier Problem n
The aim of the paper is to describe some ideas, approaches, comments, etc. regarding the Dixmier Conjecture, its generalizations and analogues
Insecticide resistance and the future of malaria control in Zambia.
BACKGROUND: In line with the Global trend to improve malaria control efforts a major campaign of insecticide treated net distribution was initiated in 1999 and indoor residual spraying with DDT or pyrethroids was reintroduced in 2000 in Zambia. In 2006, these efforts were strengthened by the President's Malaria Initiative. This manuscript reports on the monitoring and evaluation of these activities and the potential impact of emerging insecticide resistance on disease transmission. METHODS: Mosquitoes were captured daily through a series of 108 window exit traps located at 18 sentinel sites. Specimens were identified to species and analyzed for sporozoites. Adult Anopheles mosquitoes were collected resting indoors and larva collected in breeding sites were reared to F1 and F0 generations in the lab and tested for insecticide resistance following the standard WHO susceptibility assay protocol. Annual cross sectional household parasite surveys were carried out to monitor the impact of the control programme on prevalence of Plasmodium falciparum in children aged 1 to 14 years. RESULTS: A total of 619 Anopheles gambiae s.l. and 228 Anopheles funestus s.l. were captured from window exit traps throughout the period, of which 203 were An. gambiae malaria vectors and 14 An. funestus s.s.. In 2010 resistance to DDT and the pyrethroids deltamethrin, lambda-cyhalothrin and permethrin was detected in both An. gambiae s.s. and An. funestus s.s.. No sporozoites were detected in either species. Prevalence of P. falciparum in the sentinel sites remained below 10% throughout the study period. CONCLUSION: Both An. gambiae s.s. and An. funestus s.s. were controlled effectively with the ITN and IRS programme in Zambia, maintaining a reduced disease transmission and burden. However, the discovery of DDT and pyrethroid resistance in the country threatens the sustainability of the vector control programme
Feller Processes: The Next Generation in Modeling. Brownian Motion, L\'evy Processes and Beyond
We present a simple construction method for Feller processes and a framework
for the generation of sample paths of Feller processes. The construction is
based on state space dependent mixing of L\'evy processes.
Brownian Motion is one of the most frequently used continuous time Markov
processes in applications. In recent years also L\'evy processes, of which
Brownian Motion is a special case, have become increasingly popular.
L\'evy processes are spatially homogeneous, but empirical data often suggest
the use of spatially inhomogeneous processes. Thus it seems necessary to go to
the next level of generalization: Feller processes. These include L\'evy
processes and in particular Brownian motion as special cases but allow spatial
inhomogeneities.
Many properties of Feller processes are known, but proving the very existence
is, in general, very technical. Moreover, an applicable framework for the
generation of sample paths of a Feller process was missing. We explain, with
practitioners in mind, how to overcome both of these obstacles. In particular
our simulation technique allows to apply Monte Carlo methods to Feller
processes.Comment: 22 pages, including 4 figures and 8 pages of source code for the
generation of sample paths of Feller processe
Novel use of a Weerda laryngoscope for transoral excision of a cervical ganglioneuroma: a case report
<p>Abstract</p> <p>Introduction</p> <p>A ganglioneuroma is a benign neoplasm arising from neural crest cells of the sympathetic nerve fibers and is most commonly seen in the posterior mediastinum or retroperitoneum. Although very uncommon, ganglioneuromas must be included in the differential diagnosis of neck masses. In young adult women, neck incisions made for excision of these benign tumors should be avoided whenever possible.</p> <p>Case presentation</p> <p>We herein describe the case of a 19-year-old Japanese woman with a ganglioneuroma. The tumor was found in the parapharyngeal space, an unusual location. A fine-needle aspiration biopsy was performed but was considered inadequate to make a definitive diagnosis, so the asymptomatic lesion was surgically excised using a Weerda laryngoscope. The lesion measured 4 × 3 cm in size and was encapsulated. A pathological analysis showed the presence of two distinct cell types, ganglion cells and Schwann cells, embedded in a loose myxoid stroma. The final diagnosis was a ganglioneuroma.</p> <p>Conclusion</p> <p>A complete excision was made possible by using a transoral approach with a novel use of the Weerda laryngoscope. Although its applicability to specific cases depends on the location, size and nature of the tumor, we believe that the Weerda laryngoscope will continue to be useful for performing transoral surgery for cervical tumors.</p
PCR-based detection of Plasmodium in Anopheles mosquitoes: a comparison of a new high-throughput assay with existing methods
RNA editing signature during myeloid leukemia cell differentiation
Adenosine deaminases acting on RNA (ADARs) are key proteins for hematopoietic stem cell self-renewal and for survival of differentiating progenitor cells. However, their specific role in myeloid cell maturation has been poorly investigated. Here we show that ADAR1 is present at basal level in the primary myeloid leukemia cells obtained from patients at diagnosis as well as in myeloid U-937 and THP1 cell lines and its expression correlates with the editing levels. Upon phorbol-myristate acetate or Vitamin D3/granulocyte macrophage colony-stimulating factor (GM-CSF)-driven differentiation, both ADAR1 and ADAR2 enzymes are upregulated, with a concomitant global increase of A-to-I RNA editing. ADAR1 silencing caused an editing decrease at specific ADAR1 target genes, without, however, interfering with cell differentiation or with ADAR2 activity. Remarkably, ADAR2 is absent in the undifferentiated cell stage, due to its elimination through the ubiquitin–proteasome pathway, being strongly upregulated at the end of the differentiation process. Of note, peripheral blood monocytes display editing events at the selected targets similar to those found in differentiated cell lines. Taken together, the data indicate that ADAR enzymes play important and distinct roles in myeloid cells
Kuksa*: Self-Adaptive Microservices in Automotive Systems
In pervasive dynamic environments, vehicles connect to other objects to send
operational data and receive updates so that vehicular applications can provide
services to users on demand. Automotive systems should be self-adaptive,
thereby they can make real-time decisions based on changing operating
conditions. Emerging modern solutions, such as microservices could improve
self-adaptation capabilities and ensure higher levels of quality performance in
many domains. We employed a real-world automotive platform called Eclipse Kuksa
to propose a framework based on microservices architecture to enhance the
self-adaptation capabilities of automotive systems for runtime data analysis.
To evaluate the designed solution, we conducted an experiment in an automotive
laboratory setting where our solution was implemented as a microservice-based
adaptation engine and integrated with other Eclipse Kuksa components. The
results of our study indicate the importance of design trade-offs for quality
requirements' satisfaction levels of each microservices and the whole system
for the optimal performance of an adaptive system at runtime
Pancreatic adenocarcinoma in type 2 progressive familial intrahepatic cholestasis
<p>Abstract</p> <p>Background</p> <p>BSEP disease results from mutations in ABCB11, which encodes the bile salt export pump (BSEP). BSEP disease is associated with an increased risk of hepatobiliary cancer.</p> <p>Case Presentation</p> <p>A 36 year old woman with BSEP disease developed pancreatic adenocarcinoma at age 36. She had been treated with a biliary diversion at age 18. A 1.7 × 1.3 cm mass was detected in the pancreas on abdominal CT scan. A 2 cm mass lesion was found at the neck and proximal body of the pancreas. Pathology demonstrated a grade 2-3 adenocarcinoma with invasion into the peripancreatic fat.</p> <p>Conclusions</p> <p>Clinicians should be aware of the possibility of pancreatic adenocarcinoma in patients with BSEP disease.</p
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