464 research outputs found
A solution of the Gaussian optimizer conjecture
The long-standing conjectures of the optimality of Gaussian inputs for
Gaussian channel and Gaussian additivity are solved for a broad class of
covariant or contravariant Bosonic Gaussian channels (which includes in
particular thermal, additive classical noise, and amplifier channels)
restricting to the class of states with finite second moments. We show that the
vacuum is the input state which minimizes the entropy at the output of such
channels. This allows us to show also that the classical capacity of these
channels (under the input energy constraint) is additive and is achieved by
Gaussian encodings.Comment: 24 pages, no figures (minor typos corrected
The subperichondrial / subperiosteal dissection in preservation rhinoplasty: how histology can help us to perform better surgeries
Aim: The classical dissection plane in rhinoplasty is in the sub-SMAS plane with traumatic dissection
of tissues and as a result significant and prolonged postoperative edema, especially in the external approach.
A complete subperichondrial/periosteal route has been recently described. It seems to allow for simpler
postoperative follow-up than external or closed approach performed in the sub-SMAS plane. However, little
is known about the exact histological planes that are really dissected during surgery.
Material and methods: Histological examinations of 10 cadavers noses dissected in the so-called
subperichondrial/subperiosteal plane were performed.
Results: The subperichondrial plane is truly subperichondrial and consists in a dissection under the
chondrogenic layer of the perichondrium. Subperichondrial dissection necessitates sharp scrapping to separate
the cartilage from the chondrogenic layer. The perichondrium is naturally thicker on the dorsum, which
explains why it is easier to begin the dorsal dissection at the W point. Scroll cartilages are consistent and show
between 9 and 13 isolated cartilages, most of the time, 1 major and several minors cartilages. Optimal strategy
to ease the dissection is discussed
Conclusions: The subperichondrial/subperiosteal route, although necessitating significant dissection
of the teguments of the nasal pyramid, is respectful of the anatomy of the nasal pyramid. It allows minimal
traumatic maneuvers than in the sub-SMAS route, despite of the large dissection performed
The subperichondrial / subperiosteal dissection in preservation rhinoplasty: how histology can help us to perform better surgeries
Aim: The classical dissection plane in rhinoplasty is in the sub-SMAS plane with traumatic dissection
of tissues and as a result significant and prolonged postoperative edema, especially in the external approach.
A complete subperichondrial/periosteal route has been recently described. It seems to allow for simpler
postoperative follow-up than external or closed approach performed in the sub-SMAS plane. However, little
is known about the exact histological planes that are really dissected during surgery.
Material and methods: Histological examinations of 10 cadavers noses dissected in the so-called
subperichondrial/subperiosteal plane were performed.
Results: The subperichondrial plane is truly subperichondrial and consists in a dissection under the
chondrogenic layer of the perichondrium. Subperichondrial dissection necessitates sharp scrapping to separate
the cartilage from the chondrogenic layer. The perichondrium is naturally thicker on the dorsum, which
explains why it is easier to begin the dorsal dissection at the W point. Scroll cartilages are consistent and show
between 9 and 13 isolated cartilages, most of the time, 1 major and several minors cartilages. Optimal strategy
to ease the dissection is discussed
Conclusions: The subperichondrial/subperiosteal route, although necessitating significant dissection
of the teguments of the nasal pyramid, is respectful of the anatomy of the nasal pyramid. It allows minimal
traumatic maneuvers than in the sub-SMAS route, despite of the large dissection performed
The anterior cribriform plate foramina: from anatomy to surgery
Background: Despite the development of anterior skull base surgery, the anatomy of the nasal bone
and anterior cribriform plate remains unclear. A recent study confirmed 2 distinct foramina in the anterior part
of the cribriform plate: the ethmoidal slit (ES) and the cribroethmoidal foramen (CF). The aim of this study
was to specify their content, their anatomic relationship to the frontal sinus and skull base, and their potential
value in skull base surgery.
Methods: Dissections were performed on 36 cadaver heads. Macro- and microscopic examinations
were carried out. Microcomputed tomography scans contrasted with osmium were performed to identify
vessels and nerves. Histology with neural, meningeal, or luteinizing hormone-releasing hormone
immunomarkers was performed on the content of the foramina. Finally, endonasal surgical dissections were
carried out.
Results: The ES and the CF were observed in all cases. They measured a mean of 4.2 and 1.6 mm,
respectively. The ES contained dura mater, arachnoid tissues, lymphatics, and the terminal nerve. The CF
contained the anterior ethmoidal nerve and artery. This foramen continued forward with the cribroethmoidal
groove, which measured a mean of 2.5 mm. This groove was under the frontal sinus and in front of the skull
base. We also described a "cribroethmoidal canal" and a "nasal bone foramen." Clinical applications are
discussed.
Conclusion: The clinical applications of this new anatomic description concern both the cribriform
plate and frontal sinus surgeries. Identifying the terminal nerve passing through the ES is a step forward in
understanding pheromone recognition in humans
The anterior cribriform plate foramina: from anatomy to surgery
Background: Despite the development of anterior skull base surgery, the anatomy of the nasal bone
and anterior cribriform plate remains unclear. A recent study confirmed 2 distinct foramina in the anterior part
of the cribriform plate: the ethmoidal slit (ES) and the cribroethmoidal foramen (CF). The aim of this study
was to specify their content, their anatomic relationship to the frontal sinus and skull base, and their potential
value in skull base surgery.
Methods: Dissections were performed on 36 cadaver heads. Macro- and microscopic examinations
were carried out. Microcomputed tomography scans contrasted with osmium were performed to identify
vessels and nerves. Histology with neural, meningeal, or luteinizing hormone-releasing hormone
immunomarkers was performed on the content of the foramina. Finally, endonasal surgical dissections were
carried out.
Results: The ES and the CF were observed in all cases. They measured a mean of 4.2 and 1.6 mm,
respectively. The ES contained dura mater, arachnoid tissues, lymphatics, and the terminal nerve. The CF
contained the anterior ethmoidal nerve and artery. This foramen continued forward with the cribroethmoidal
groove, which measured a mean of 2.5 mm. This groove was under the frontal sinus and in front of the skull
base. We also described a "cribroethmoidal canal" and a "nasal bone foramen." Clinical applications are
discussed.
Conclusion: The clinical applications of this new anatomic description concern both the cribriform
plate and frontal sinus surgeries. Identifying the terminal nerve passing through the ES is a step forward in
understanding pheromone recognition in humans
Reducing the burden of iron deficiency anemia in Cote D'Ivoire through fortification
Iron deficiency anemia (IDA) is highly prevalent in the Cote d'Ivoire and has severe health and economic consequences. In this paper, we apply a health economic model to quantify the burden of IDA, and the contribution of nationwide mandatory iron fortification of wheat flour and voluntary iron fortification of condiments to the reduction of this burden
Isolated hypoglossal palsy due to cervical osteophyte
SummaryIntroductionIsolated hypoglossal nerve palsy is rare, and etiological diagnosis is difficult. We report a case of isolated hypoglossal compression by a cervical osteophyte in the hypoglossal canal exit.Case studyAn 86-year-old woman with history of cervical spondylotic myelopathy consulted for a lesion of the free edge of the tongue with impaired elocution. Clinical examination found a bite lesion on the right free edge of the tongue with right lingual amyotrophy and associated left deviation on retraction. Isolated right hypoglossal palsy was diagnosed. Skull base CT found a cervical osteophyte compressing the hypoglossal nerve at the exit from the right hypoglossal canal. Surgery was contra-indicated by the patient's general health status. No motor recovery was observed at 6 months’ follow-up, but the elocution disorders regressed under speech therapy.ConclusionHypoglossal palsy is infrequent, but generally a sign of skull base pathology. History-taking and careful examination guide rational selection of the radiological examinations required for etiological diagnosis
Electromagnetic channel capacity for practical purposes
We give analytic upper bounds to the channel capacity C for transmission of
classical information in electromagnetic channels (bosonic channels with
thermal noise). In the practically relevant regimes of high noise and low
transmissivity, by comparison with know lower bounds on C, our inequalities
determine the value of the capacity up to corrections which are irrelevant for
all practical purposes. Examples of such channels are radio communication,
infrared or visible-wavelength free space channels. We also provide bounds to
active channels that include amplification.Comment: 6 pages, 3 figures. NB: the capacity bounds are constructed by
generalizing to the multi-mode case the minimum-output entropy bounds of
arXiv:quant-ph/0404005 [Phys. Rev. A 70, 032315 (2004)
Diabetes Screening and Prevention in a High-Risk, Medically Isolated Border Community
Introduction: A project in a Texas border community setting, Prevention Organized against Diabetes and Dialysis with Education and Resources (POD2ER), offered diabetes prevention information, screening, and medical referrals. The setting was a large, longstanding flea market that functions as a shopping mall for low-income people. The priority population included medically underserved urban and rural Mexican Americans. Components of the program addressed those with diabetes, prediabetes, and accompanying relatives and friends.
Background: People living in the Lower Rio Grande Valley (LRGV) face challenges of high rates of type 2 diabetes, lack of knowledge about prevention, and inadequate access to medical care. Recent statistics from actual community-wide screenings indicate a high diabetes prevalence, 30.7% among adults in the LRGV compared with 12.3% nationwide.
Methods: A diverse team composed of public health faculty, students, a physician, a community health worker, and community volunteers conceived and developed the project with a focus on cultural and economic congruence and a user-friendly atmosphere. The program provided screening for prediabetes and diabetes with a hemoglobin A1c test. Screening was offered to those who were at least 25 years of age and not pregnant. When results indicated diabetes, a test for kidney damage was offered (urinary albumin-to-creatinine ratio). A medical appointment at a community clinic within a week was provided to those who tested positive for diabetes and lacked a medical home. Health education modules addressed all family members.
Discussion: The project was successful in recruiting 2,332 high-risk people in 26 months in a community setting, providing clinic referrals to those without a doctor, introducing them to treatment, and providing diabetes prevention information to all project participants. Implications for research and practice are highlighted.
Conclusion: This study shows that a regular access point in a place frequented by large numbers of medically marginalized people in a program designed to eliminate cultural and economic barriers can succeed in providing a hard-to-reach community with diabetes prevention services. Aspects of this program can serve as a model for other service provision for similar populations and settings
Continuous variable quantum key distribution with two-mode squeezed states
Quantum key distribution (QKD) enables two remote parties to grow a shared
key which they can use for unconditionally secure communication [1]. The
applicable distance of a QKD protocol depends on the loss and the excess noise
of the connecting quantum channel [2-10]. Several QKD schemes based on coherent
states and continuous variable (CV) measurements are resilient to high loss in
the channel, but strongly affected by small amounts of channel excess noise
[2-6]. Here we propose and experimentally address a CV QKD protocol which uses
fragile squeezed states combined with a large coherent modulation to greatly
enhance the robustness to channel noise. As a proof of principle we
experimentally demonstrate that the resulting QKD protocol can tolerate more
noise than the benchmark set by the ideal CV coherent state protocol. Our
scheme represents a very promising avenue for extending the distance for which
secure communication is possible.Comment: 8 pages, 5 figure
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