Accuracy and reliability of digital craniofacial measurements using a small-format, handheld 3D camera.

OBJECTIVES: Craniofacial assessments often involve three-dimensional facial imaging using an expensive camera with 6 SLR lenses to analyse the positions and relations of anatomic landmarks. Recently, a 3D small-format, handheld camera was developed; however, the accuracy and reliability of this system are largely unknown. The purpose of this study was to evaluate the accuracy and reliability of this system. MATERIALS & METHODS: A total of 30 sets of evaluations were completed by 2 examiners on 5 human subjects, using 3 different methods: direct callipers, 3D handheld camera and conventional tripod 3D camera images. Each evaluation included 29 anthropometric landmarks that were used as reference points for facial analysis. Two examiners marked the landmarks directly on the faces and measured linear distances using the 3 measurement methods. RESULTS: Accuracy analysis was performed for handheld vs direct calliper vs conventional camera measurements. Each of these analyses yielded a grand mean of correlation coefficients of .98. Bias measurements revealed that the handheld and conventional camera methods yielded larger measurements than direct callipers (with a mean difference of 1.74, 1.56 mm, respectively, for rater 1 and 0.94, 1.02 mm, respectively, for rater 2). When compared to one another, both the handheld camera and the conventional camera methods yielded similar values for most measurements, with the average overall difference between these modalities of 0.03 mm for rater 1 and 0.07 mm for rater 2. CONCLUSIONS: The 3D handheld camera showed high accuracy and reliability in comparison with traditional models, indicating that this system may provide a useful tool in craniofacial anthropometry.

Experimental Study of Optimal Measurements for Quantum State Tomography.

Quantum tomography is a critically important tool to evaluate quantum hardware, making it essential to develop optimized measurement strategies that are both accurate and efficient. We compare a variety of strategies using nearly pure test states. Those that are informationally complete for all states are found to be accurate and reliable even in the presence of errors in the measurements themselves, while those designed to be complete only for pure states are far more efficient but highly sensitive to such errors. Our results highlight the unavoidable trade-offs inherent in quantum tomography.

Robust site-resolvable quantum gates in an optical lattice via inhomogeneous control.

The power of optical lattices for quantum simulation and computation is greatly enhanced when atoms at individual lattice sites can be accessed for measurement and control. Experiments routinely use high-resolution microscopy to obtain site-resolved images in real time, and site-resolved spin flips have been implemented using microwaves resonant with frequency-shifted target atoms in focused light fields. Here we show that methods adapted from inhomogeneous control can greatly increase the performance of such resonance addressing, allowing the targeting of arbitrary single-qubit quantum gates on selected sites with minimal cross-talk to neighbouring sites and significant robustness against uncertainty in the atom position. We further demonstrate the simultaneous implementation of different gates at adjacent sites with a single global microwave pulse. Coherence is verified through two-pulse experiments, and the average gate fidelity is measured to be 95±3%. Our approach may be useful in other contexts such as ion traps and nitrogen-vacancy centres in diamond.

Atomic motion in magneto-optical double-well potentials: a testing ground for quantum chaos.

We have identified ultracold atoms in magneto-optical double-well potentials as a very clean setting in which to study the quantum and classical dynamics of a nonlinear system with multiple degrees of freedom. In this system, entanglement at the quantum level and chaos at the classical level arise from nonseparable couplings between the atomic spin and its center of mass motion. The main features of the chaotic dynamics are analyzed using action-angle variables and Poincaré surfaces of section. We show that for the initial state prepared in current experiments [D. J. Haycock et al., Phys. Rev. Lett. 85, 3365 (2000)], classical and quantum expectation values diverge after a finite time, and the observed experimental dynamics is consistent with quantum-mechanical predictions. Furthermore, the motion corresponds to tunneling through a dynamical potential barrier. The coupling between the spin and the motional subsystems, which are very different in nature from one another, leads to interesting questions regarding the transition from regular quantum dynamics to chaotic classical motion.

Phase diffusion as a model for coherent suppression of tunneling in the presence of noise.

We study the stabilization of coherent suppression of tunneling in a driven double-well system subject to random periodic delta-function "kicks." We model dissipation due to this stochastic process as a phase diffusion process for an effective two-level system, and derive a corresponding set of Bloch equations with phase damping terms that agree with the periodically kicked system at discrete times. We demonstrate that the ability of noise to localize the system on either side of the double-well potential arises from overdamping of the phase of oscillation, and not from any cooperative effect between the noise and the driving field. The model is investigated with a square wave drive, which has qualitatively similar features to the widely studied cosinusoidal drive, but has the additional advantage of allowing one to derive exact analytic expressions.

Spatial correlation diagnostics for atoms in optical lattices.

We explore the use of first and second order same-time atomic spatial correlation functions as a diagnostic for probing the small scale spatial structure of atomic samples trapped in optical lattices. Assuming an ensemble of equivalent atoms, properties of the local wave function at a given lattice site can be measured using same-position first-order correlations. Statistics of atomic distributions over the lattice can be measured via two-point correlations, generally requiring the averaging of multiple realizations of statistically similar but distinct realizations in order to obtain sufficient signal to noise. Whereas two-point first order correlations are fragile due to phase fluctuations from shot-to-shot in the ensemble, second order correlations are robust. We perform numerical simulations to demonstrate these diagnostic tools.

Laparoscopic splenectomy for immune thrombocytopenic purpura.

Splenectomy is an effective treatment for immune thrombocytopenic purpura (ITP). The recent advances in laparoscopic technique and technology have made laparoscopic splenectomy a viable option. Over 36 months we performed a total of 17 laparoscopic splenectomies, 15 of them for ITP and 2 for familial spherocytosis. We present our initial experience with laparoscopic splenectomy in 15 patients (age 16-71 years) with ITP. Operations were performed 2-24 months after the establishment of the diagnosis and initiation of appropriate therapy. Technically, the splenic artery was clipped first; the lower pole of the spleen and its posterolateral attachments were dissected using endoclips and electrocautery; the hilum and short gastric vessels were separated using an endostapler; the spleen was placed in a plastic bag, its opening pulled out through the umbilical incision, and the spleen fragmented and aspirated out of the bag. Operations lasted 100-300 min (mean 170 min). No patient required blood transfusion. The postoperative course was uneventful in all patients with minimal requirement of analgesia and early return to normal activity. Platelet counts returned to normal in all patients in a follow-up period of 2-36 months. Laparoscopic splenectomy is safe and effective for patients with ITP because of reduced operative trauma, less postoperative pain, cosmetic advantage, and possibly less postoperative complications.

[Laparoscopic colonic resection].

We present our initial experience with laparoscopic colonic resection in 15 patients: adenocarcinoma of the colon, 10 cases, giant villous adenoma (2), arteriovenous malformation (2), and a case of benign stricture. Mean operating time was 190 minutes and there were no intraoperative complications. The margins of resection and number of resected lymph nodes in patients with malignancy were comparable to those in the conventionally operated. Mean postoperative hospital stay was 6.1 days. During a maximum follow-up of 15 months there were no wound or trocar-site recurrences. We conclude that laparoscopic colonic resection is technically feasible and safe. However, its use for treating malignant diseases of the colon needs further study.

[Laparoscopic splenectomy for immune thrombocytopenic purpura].

Splenectomy is effective in treating immune thrombocytopenic purpura (ITP). Recent advances in laparoscopic technique and technology have made laparoscopic splenectomy feasible. We performed it in 8 cases of ITP (16-34 years old, and 2-24 months after the diagnosis was made and appropriate treatment started). Indications for splenectomy were no response to corticosteroid therapy (2 patients), decrease in platelet count when attempting to taper off therapy (3), or severe side-effects of the treatment (3). 4-5 ports were used. The splenic artery was first double-clipped through an opening in the gastrocolic ligament and then the lower splenic pole and the posterolateral attachments were dissected using endoclips and electrocautery. The hilum and short gastric vessels were separated using an endostapler. The spleen was placed in a plastic bag whose open end was pulled out through an umbilical incision and the spleen fragmented and aspirated out of the bag, while it was still inside the abdomen. Blood or platelet transfusions were not needed and the postoperative course was uneventful in all, with early return to full normal activity. Postoperatively, platelets increased to more than 150,000/mm3 in all patients, and there was no further need for corticosteroids during a follow-up of 2-12 months. We recommend laparoscopic splenectomy for ITP because of the reduced operative trauma, better recovery and rehabilitation, less postoperative pain, cosmetic advantage, and possibly fewer postoperative complications.

Membrane lipids of Mycoplasma fermentans.

Membranes of Mycoplasma fermentans, incognitus strain, were isolated by a combination of osmotic lysis and sonication. Analysis of membrane lipids revealed, in addition to free and esterified cholesterol, six major polar lipids dominated by a de novo synthesized compound (compound X), which accounts for 64% of the total lipid phosphorus. Compound X was labeled by palmitate, but not by oleate. Mass spectrometry and gas liquid chromatography analyses of compound X revealed two molecular species with molecular masses of 1048 and 1076 representing, a dipalmitoyl- and a stearoyl-palmitoyl-glycerodiphosphatidylcholine. Compound X has the ability to stimulate human monocytes to secret TNF alpha and to enhance the fusion of small unilamellar vesicles with MOLT-3 lymphocytes.

Erythrocyte Li+i-Na+o countertransport in the newborn.

The present study investigates the erythrocyte Li+i-Na+o countertransport (CT) in the newborn. Erythrocytes of term infants exhibit no or very low CT activity at birth (0.025 +/- 0.011 mmol Li/l RBC.h). CT rates increase gradually and reach adult values within the 4th-7th day of life (0.225 +/- 0.018 mmol Li/l RBC.h). CT activity in healthy preterm infants at birth is not significantly different from that in term infants (0.014 +/- 0.007 mmol Li/l RBC.h). Postnatal maturation of CT activity in preterm infants is similar to that found in term infants and is independent of gestational age. However, CT rates at birth of premature infants subjected to prenatal stress are significantly higher (0.082 +/- 0.017 mmol Li/l RBC.h). It is concluded that erythrocyte CT activity in the newborn reaches adult values within the first week of life, apparently reflecting the postnatal maturation of the CT system in the cell membrane. We suggest that prenatal stress induces the synthesis of the CT protein in utero.

Approximate formulae (deduced from a mathematical model) for the characteristics of the interepidemic and epidemic periods of some virus diseases.

By a qualitative analysis of the solutions of the mathematical model equations (describing the morbidity and susceptibility evolution in a viral epidemics), approximate formulae for the extreme values of the variables and for the duration of the main phases of a multiannual cycle are deduced. These formulae were validated by numerical simulation of the solutions, leading to the exact values of the mentioned essential characteristics of the diseases propagation.

[The knowledge and attitudes of medical students in their 2d year about AIDS]. / Connaissances et attitudes des étudiants en médecine de deuxième année en ce qui concerne le SIDA.

This study had two specific aims: determining the level of knowledge about AIDS acquired through the courses on this subject; analysing the students' attitude towards the disease, with respect to different aspects related to the future professional risk. For this purpose, a questionnaire was made up and from the answers a data base was set up, processed and stored for further studies. We analysed to which extent the students are acquainted with the routes of transmission of HIV infection, with the groups of risk and with the groups of ages exposed to contagion in Romania. We were interested in whether the students recognize the clinical signs of the disease, the diagnosis methods and the specific medicines used. We studied to which extent the students consider the routine HIV diagnosis necessary for all hospitalised patients, for foreigners residing in Romania, for Romanians working abroad, as well as for couples before marriage. In order to have a clear image on the students' opinion about the risk of getting the disease in general as well as on their fears concerning the professional risk of infection, several questions in this regard were included in the questionnaire. Another important aspect of the study consists in estimating the degree to which the knowledge acquired through the courses make the students able to offer in their turn useful and credible information to their family, friends or strangers. The students' perception of AIDS is mainly determined by the risk of sexual contamination, while the control measures regarding the interruption of the other ways are underestimated.

The control of some viral epidemics by antiepidemic programmes elaborated by an expert system.

A base of data for viral epidemiological studies is presented containing correlation between outer symptoms (observable characteristics of the mass morbid phenomena), inner symptoms (characteristics of intensity of elementary processes implied in the virosis propagation) and influencing factors (risk or protective ones). A resolutive nucleus of processing these is divided in to three parts: an inductive one (specification of the mentioned correlations, of the mathematical model and its equation solutions); a deductive one (explaining or prognosing the epidemiological evolution); a decisional one (specifying the antiepidemic services, necessary for a possible or desired reduction of the morbidity).

[The improvement of a serological screening method in blood transfusion]. / Perfectionnement d'une méthodologie de screening sérologique en transfusion sanguine.

The mathematical analysis was done of the opportunity of modifying the serological screening method in view of the reduction to a minimum of the costs. Two factors were considered: dimensions of the pool and specific incidence of the markers in the population.

[Assessment of the epidemiological parameters of the most widespread viral diseases in the Socialist Republic of Romania and in Sibiu County for period 1967-1986]. / Estimation des paramètres épidémiologiques des viroses les plus répandues en R.S. de Roumanie et dans le département de Sibiu pour l'intervalle 1967-1986.

Essential peculiarities of the kinetics of the morbidity evolution of most frequent virus diseases were explained using a determinant mathematical model. The main epidemiological parameters for the whole territory of the S.R. of Romania and of Sibiu County were evaluated for the 1967-1986 period.