Single-Shot Non-Gaussian Measurements for Optical Phase Estimation.

Estimation of the properties of a physical system with minimal uncertainty is a central task in quantum metrology. Optical phase estimation is at the center of many metrological tasks where the value of a physical parameter is mapped to the phase of an electromagnetic field and single-shot measurements of this phase are necessary. While there are measurements able to estimate the phase of light in a single shot with small uncertainties, demonstrations of near-optimal single-shot measurements for an unknown phase of a coherent state remain elusive. Here, we propose and demonstrate strategies for single-shot measurements for ab initio phase estimation of coherent states that surpass the sensitivity limit of heterodyne measurement and approach the Cramer-Rao lower bound for coherent states. These single-shot estimation strategies are based on real-time optimization of coherent displacement operations, single photon counting with photon number resolution, and fast feedback. We show that our demonstration of these optimized estimation strategies surpasses the heterodyne limit for a wide range of optical powers without correcting for detection efficiency with a moderate number of adaptive measurement steps. This is, to our knowledge, the most sensitive single-shot measurement of an unknown phase encoded in optical coherent states.

Robust Measurement for the Discrimination of Binary Coherent States.

The discrimination of two nonorthogonal states is a fundamental element for secure and efficient communication. Quantum measurements of nonorthogonal coherent states can enhance information transfer beyond the limits of conventional technologies. We demonstrate a strategy for binary state discrimination based on optimized single-shot measurements with photon number resolving detection with a finite number resolution. This strategy enables a high degree of robustness to noise and imperfections while being scalable to high rates and, in principle, allows for surpassing the quantum noise limit (QNL) in practical situations. These features make the strategy inherently compatible with high-bandwidth communication and quantum information applications, providing advantages over the QNL under realistic conditions.

Clustering autism: using neuroanatomical differences in 26 mouse models to gain insight into the heterogeneity.

Autism is a heritable disorder, with over 250 associated genes identified to date, yet no single gene accounts for >1-2% of cases. The clinical presentation, behavioural symptoms, imaging and histopathology findings are strikingly heterogeneous. A more complete understanding of autism can be obtained by examining multiple genetic or behavioural mouse models of autism using magnetic resonance imaging (MRI)-based neuroanatomical phenotyping. Twenty-six different mouse models were examined and the consistently found abnormal brain regions across models were parieto-temporal lobe, cerebellar cortex, frontal lobe, hypothalamus and striatum. These models separated into three distinct clusters, two of which can be linked to the under and over-connectivity found in autism. These clusters also identified previously unknown connections between Nrxn1α, En2 and Fmr1; Nlgn3, BTBR and Slc6A4; and also between X monosomy and Mecp2. With no single treatment for autism found, clustering autism using neuroanatomy and identifying these strong connections may prove to be a crucial step in predicting treatment response.

Implementation of generalized quantum measurements for unambiguous discrimination of multiple non-orthogonal coherent states.

Generalized quantum measurements implemented to allow for measurement outcomes termed inconclusive can perform perfect discrimination of non-orthogonal states, a task which is impossible using only measurements with definitive outcomes. Here we demonstrate such generalized quantum measurements for unambiguous discrimination of four non-orthogonal coherent states and obtain their quantum mechanical description, the positive-operator valued measure. For practical realizations of this positive-operator valued measure, where noise and realistic imperfections prevent perfect unambiguous discrimination, we show that our experimental implementation outperforms any ideal standard-quantum-limited measurement performing the same non-ideal unambiguous state discrimination task for coherent states with low mean photon numbers.

IgG subclasses against Helicobacter pylori isolates: an important tool for disease characterization.

Helicobacter pylori infects around 50% of the world's population and is associated with diverse pathologies. In the most severe cases, the bacterium causes peptic ulcers and gastric cancer. The interplay between H. pylori and the host's immune response may help to determine the specific outcome of the infection. To study the relationship between antibody subclasses and variation in immune recognition, we determined the immunoglobulin G1 and 2 (IgG1 and IgG2) titres of sera obtained from patients with different H. pylori-associated pathologies. IgG1 and IgG2 titres were determined by ELISA in 44 sera of patients with different H. pylori-associated diseases (peptic ulcer, bleeding peptic ulcers, gastric cancer and dyspepsia). Soluble proteins from lysates were obtained from 12 different clinical isolates from similar associated diseases. We found that soluble proteins from lysates of H. pylori strains (SPLHP) recognition patterns in these sera were highly variable. Overall, IgG2 titres were higher than the IgG1 titres in the infected patients. In particular, those with peptic ulcers showed marked elevation in IgG2/IgG1 ratios, while SPLHPs from dyspeptic patients resulted in high IgG1 titres. Our results reveal that correlation of antibody subclass titres with Th1/Th2 markers may aid pathology characterization and show a potential diagnosis that could be formally evaluated in other studies.

Histochemical and morphometric analyses of the musculature of the forelimb of the subterranean rodent Ctenomys talarum (Octodontoidea).

Histochemical and morphometric analyses were performed to characterize the fibre-type composition of two forelimb muscles of the South American subterranean rodent Ctenomys talarum. The studied muscles were the triceps lateralis, an extensor of the elbow, and the teres major, a flexor of the shoulder. It was found that these muscles had an elevated proportion of fast oxidative-glycolytic (FOG) fibres, and lower proportions of slow oxidative (SO) and fast glycolytic (FG) fibres. This composition probably qualifies the teres major and triceps muscles to perform the sustained effort required in tunnelling excavation. The results were discussed considering published data on fibre-type composition of mammals having different modes of life and digging behaviour. We here suggest that C. talarum has the potential of generating forces linked to rapid, powerful movements during sustained periods by means of an elevated proportion of FOG fibres, together with osteological changes that result in a great mechanical advantage of the forelimb muscles.

Photon statistics and polarization correlations at telecommunications wavelengths from a warm atomic ensemble.

We present measurements of the polarization correlation and photon statistics of photon pairs that emerge from a laser-pumped warm rubidium vapor cell. The photon pairs occur at 780 nm and 1367 nm and are polarization entangled. We measure the autocorrelation of each of the generated fields as well as the cross-correlation function, and observe a strong violation of the two-beam Cauchy-Schwartz inequality. We evaluate the performance of the system as source of heralded single photons at a telecommunication wavelength. We measure the heralded autocorrelation and see that coincidences are suppressed by a factor of ≈ 20 from a Poissonian source at a generation rate of 1500 s(-1), a heralding efficiency of 10%, and a narrow spectral width.

Mortalidad en prematuros tratados con surfactante exógeno / Mortality in premature infants treated with exogenous surfactant

Objective: Characterize mortality and associated factors in Chilean prematures born < 32 weeks of gestational age (GA) and treated with exogenous surfactant. Method: Cohort of newborns (n = 2 868) registered between 1998-2005 in the database of the Surfactant National Program. The association of gestational and neonatal variables with mortality was estimated through survival analysis and logistic regression. Results: Global mortality was 35 percent, varying by GA from 86.7 percent (< 25 weeks) to 12.6 percent (32 weeks). There was a clear decrease of mortality during the study period, along with a fall in the gestational age and birth weight (BW) of the patients who died (1 021 g +/- 295 to 854 g +/- 258) and GA (27.7 +/- 2.1 to 26.5 +/- 23) during this period. Pulmonary hemorrhage (PH) was the most important factor associated to mortality, so we decided to stratify the analysis by this condition. In children with PH, the mortality estimated risk lower as the GA increased (OR= 0.73; CI95 0.57-0.93) and every 100 g of additional BW (OR= 0.74; CI95 0.63-0.88). Children not affected by PH also had their OR diminished with major GA (OR= 0.82; CI95 0.76-0.90) and more BW (OR= 0.84; CI95 0.79 - 0.89). In addition, the OR decreased with better Apgar 5 min score (OR= 0.80; CI95 0.75-0.85), use of prenatal corticoids (OR= 0.71; CI95 0.56-0.90) and was higher in boys (OR= 1.36; CI95 1.08-1.71). Conclusions: Mortality in premature newborns decreased 15 percent during this period. Inmaturity and extreme low birth weight factors constitute a challenge to improve survival and avoid further complications like PH.

Objetivo: Caracterizar la mortalidad y factores asociados en prematuros chilenos < 32 semanas de edad gestacional (EG) receptores de surfactante exógeno. Pacientes y Métodos: Cohorte de neonatos 1998-2005 (n = 2 868) de la base de datos del Programa Nacional de Surfactante. Se estimó la mortalidad y su relación con variables maternas, del embarazo y neonatales mediante análisis de sobrevida y regresión logística. Resultados: La mortalidad global fue 35 por ciento, variando por EG entre 86,7 por ciento (< 25 semanas) y 12,6 por ciento (32 semanas). La mortalidad descendió en el período, reduciéndose también el peso de nacimiento (PN) de los fallecidos (1 02 lg +/- 295 a 854 g +/- 258) y su EG (27,7 +/- 2,1 a 26,5 +/- 2,3). La hemorragia pulmonar (HP) fue el factor más importante asociado a mortalidad, por lo que se estratificó el análisis por esa condición. En niños con HP, cada semana adicional de EG disminuye el riesgo de morir (OR: 0,73; IC95 0,57-0,93), así como por cada 100 g de peso adicional (OR: 0,74; IC95 0,63-0,88). Sin HP, el riesgo disminuye con mayor EG (OR: 0,82; IC95 0,76-0,90), mayor PN (OR: 0,84; IC95 0,79-0,89), mejor puntuación Apgar 5 minutos (OR: 0,80; IC95 0,75-0,85) y uso de corticoide prenatal (OR: 0,71; IC95 0,56-0,90), siendo significativamente mayor en varones (OR: 1,36; IC(95)1,08-1,71). Conclusiones: En el período, la mortalidad en prematuros disminuyó en 15 por ciento. La inmadurez y extremo bajo peso de niños actualmente viables, plantean importantes desafíos para mejorar su sobrevida y evitar complicaciones, entre ellas, la HP.

Cintigrafía tiroídea (CT) con Tc99m-pertecnectato en recién nacidos (RN) con hipotiroidismo congénito (HC) / Tc99m-pertechnetate thyroid scintigraphy in newborns with congenital hypothyroidism

Background: Congenital hypothyroidism is one of the most frequent endocrine diseases of the newborn and requires an early diagnosis to avoid its deleterious effects on neurological and intellectual functions. Aim: To evaluate thyroid scintigraphy (TS) findings in newborns with congenital hypothyroidism (CH), detected in the national program of newborn screening, which is working in Chile since 1992. Material and methods : TS findings of 189 newborns with CH (68 percent female) were analyzed. Tc99m pertechnetate TS was performed at 19 ñ 11 days of life. The gland was classified as eutopic, ectopic or absence of contrast (AC). Eutopic glands were classified by visual and quantitative criteria as: normal, goiter and decreased contrast (DC). TS results were compared by gender and hormonal levels. Results: Forty seven percent of newborns had ectopy, 29.1 percent eutopy and 24.3 percent AC. Eutopic gland predominated in males (44.2 percent vs 22.7 percent) and ectopy was more frequent in girls (53.1 percent vs 32.8 percent, p <0.05). Newborns with AC had the most severe hormonal alterations, without gender differences. Newborns with normal TS had less hormonal alterations than those with goiter. Conclusions: TS allows an etiological classification of CH. Thyroid dysgenesis is the most frequent cause, most of which correspond to ectopy, especially in girls. Eutopic glands are present in one third of newborns with CH. Goiter predominates, especially in males

Initial stress differences between sliding and sectional mechanics with an endosseous implant as anchorage: a 3-dimensional finite element analysis.

Endosseous implants have been used as orthodontic anchorage in recent years. A 3-dimensional mathematical model was constructed that uses the finite element method, which simulated an endosseous implant and an upper canine with its periodontal ligament and cortical and cancellous bone. Levels of initial stress were measured during 2 types of canine retraction mechanics (friction and frictionless). The lower magnitude and more uniform stresses in the implant and its cortical bone were found to have a moment-force ratio (M/F) of 6.1:1, whereas the canine and its supporting structures exerted a M/F ratio of 10.3:1. On the basis of these results, when the anchor unit is an endosseous implant, it seems better to use a precalibrated retraction system without friction (T-loop) where a low load-deflection curve would be generated.

[Oral rehydration solutions with 60 or 90 nmol/L of sodium for infants with acute diarrhea in accord with their nutritional status]. / Soluciones de rehidratación oral con 60 ó 90 mmol/L de sodio en niños con diarrea aguda de acuerdo a su estado nutricional.

A total of 186 infants suffering from dehydration due to acute diarrhea were studied and divided into two groups: 84 children were placed in group A and received the oral rehydration solution (ORS) recommended by the World Health Organization (WHO), know as ORS-90 and those placed in group B were given an ORS with 60 and 90 mmol/L of sodium and glucose, respectively, with an osmolality of 240 mOsm/kg (ORS-60). Seven patients from group A (8.3%) and two from group B (2.5%) could not be orally rehydrated and required intravenous rehydration. The children were divided according to their weight for their age into eutrophics, grade I malnutrition (10 to 25% deficit), grade II (26 to 40% deficit) and grade III (more than 40% deficit). In those patients who evolved favorably, the average rehydration time was 4.5 to 5.3 hours, independently from their nutritional state. In the same way, no important variations were seen in the average sodium and potassium serum levels once the dehydration was corrected, in either of the groups. Yet, both groups showed a persistence in hypokalemia and hyperkalemia seen when admitted, once the dehydration was corrected, demonstrating that the short time needed for the correction of the dehydration was insufficient to completely corrected the changes in serum potassium. Closer studies must be conducted on the hydric balance to adequately demonstrate if the new ORS-60 induces lesser losses through vomiting and feces when compared to the ORS-90 recommended by the WHO.

[Comparative study of 2 oral rehydration solutions containing 60 or 90 mmol/L of sodium and with different osmolalities]. / Estudio comparativo de dos soluciones de hidratación oral conteniendo 60 ó 90 mmol/L de sodio y con diferente osmolalidad.

A total of 186 infants, suffering from acute diarrhea were studied and divided into two groups: 84 children were placed in group A and given the ORS recommended by the World Health Organization which contains sodium and glucose at concentrations of 60 and 90 mmol/L respectively and an osmolality of 311 mOsm/kg (mmol/kg) (ORS-90). Group B included 82 children who received an ORS containing sodium and glucose at concentrations of 60 and 90 mmol/L respectively and with an osmolality of 240 mOsm/kg (mmol/kg) (ORS-60). Seven belonging to group A (8.3%) required intravenous rehydration due to the severity of the diarrhea (three cases), persistent vomiting (three cases) and paralytic ileus (one case), while only two cases belonging to group B (2.5%) required intravenous rehydration due to severe losses through feces (one case) and another due to paralytic ileus (one case). No differences were observed due to the variations in sodium concentrations among either of the groups of patients, whether that be in the natremias when admitted or once rehydrated, with a general tendency towards the correction of the hypernatremia or hyponatremia seen during admittance with both types of ORS. A similar situation was observed with the variations in serum potassium. The results obtained from this study show the different advantages of using an ORS with lesser sodium and glucose concentrations as well as minor osmolality with those from using the solution recommended by the World Health Organization, when a lesser index of failures is observed in the treatment of children with acute diarrhea with oral rehydration therapy. Yet before widely recommending its' use, it should be demonstrated that the new ORS induces lesser losses through feces during the rehydrating period in children dehydrated due to acute diarrhea.

Clinical experience in Mexico with a new oral rehydration solution with lower osmolality.

A clinical trial was conducted to compare the safety and efficacy of a new oral rehydration solution (ORS) with that of the ORS recommended by the World Health Organization (WHO). One hundred thirty infants with dehydration due to acute diarrhea were randomized into two groups: 68 infants received the WHO ORS containing sodium and glucose in a concentration of 90 and 111 mmol/L, respectively, and an osmolality of 311 mosm/kg (ORS-90); 62 infants received an ORS containing sodium and glucose in a concentration of 60 and 90 mmol/L, respectively, with an osmolality of 240 mosm/kg (ORS-60). Treatment failure was noted in seven infants (10.3%) in the ORS-90 group; the causes of failure were high stool output (three cases), persistent vomiting (three cases), and ileus (one case). Only one patient in the ORS-60 group (1.6%) was considered a failure because of high stool output. No significant differences were noted in the serum sodium levels in either group of patients, both in relation to the natremia seen on admittance or that seen after rehydration. A trend was observed toward correction of hypernatremia or hyponatremia with both types of ORS. A similar situation was observed with respect to the variations seen in serum potassium levels. The results from this study suggest that there may be clinical advantages of using an ORS with concentrations of sodium and glucose and a total osmolality lower than that of ORS-90, because of the lower incidence of treatment failures.