Estimation with ultimate quantum precision of the transverse displacement between two photons via two-photon interference sampling measurements

We present a quantum sensing scheme achieving the ultimate quantum sensitivity in the estimation of the transverse displacement between two photons interfering at a balanced beam splitter, based on transverse-momentum sampling measurements at the output. This scheme can possibly lead to enhanced high-precision nanoscopic techniques, such as super-resolved single-molecule localization microscopy with quantum dots, by circumventing the requirements in standard direct imaging of cameras resolution at the diffraction limit, and of highly magnifying objectives. Interestingly, the ultimate spatial precision in nature is achieved irrespectively of the overlap of the two displaced photonic wavepackets. This opens a new research paradigm based on the interface between spatially resolved quantum interference and quantum-enhanced spatial sensitivity.Comment: 13 pages, 4 figure

Klinefelter syndrome: cardiovascular abnormalities and metabolic disorders

Klinefelter syndrome (KS) is one of the most common genetic causes of male infertility. This condition is associated with much comorbidity and with a lower life expectancy. The aim of this review is to explore more in depth cardiovascular and metabolic disorders associated to KS. KS patients have an increased risk of cerebrovascular disease (standardized mortality ratio, SMR, 2.2; 95% confidence interval, CI, 1.6-3.0), but it is not clear whether the cause of the death is of thrombotic or hemorrhagic nature. Cardiovascular congenital anomalies (SMR, 7.3; 95% CI, 2.4-17.1) and the development of thrombosis or leg ulcers (SMR, 7.9; 95% CI, 2.9-17.2) are also more frequent in these subjects. Moreover, cardiovascular abnormalities may be at least partially reversed by testosterone replacement therapy (TRT). KS patients have also an increased probability of endocrine and/or metabolic disease, especially obesity, metabolic syndrome and type 2 diabetes mellitus. The effects of TRT on these abnormalities are not entirely clear

The Role of Auxiliary Stages in Gaussian Quantum Metrology

The optimization of the passive and linear networks employed in quantum metrology, the field that studies and devises quantum estimation strategies to overcome the levels of precision achievable via classical means, appears to be an essential step in certain metrological protocols achieving the ultimate Heisenberg-scaling sensitivity. This optimization is generally performed by adding degrees of freedom by means of auxiliary stages, to optimize the probe before or after the interferometric evolution, and the choice of these stages ultimately determines the possibility to achieve a quantum enhancement. In this work we review the role of the auxiliary stages and of the extra degrees of freedom in estimation schemes, achieving the ultimate Heisenberg limit, which employ a squeezed-vacuum state and homodyne detection. We see that, after the optimization for the quantum enhancement has been performed, the extra degrees of freedom have a minor impact on the precision achieved by the setup, which remains essentially unaffected for networks with a larger number of channels. These degrees of freedom can thus be employed to manipulate how the information about the structure of the network is encoded into the probe, allowing us to perform quantum-enhanced estimations of linear and non-linear functions of independent parameters

Momentum-entangled two-photon interference for quantum-limited transverse-displacement estimation

We propose a scheme achieving the ultimate quantum precision for the estimation of the transverse displacement between two interfering photons. Such a transverse displacement could be caused, for example, by the refracting properties of the propagation medium, or by the orientation of a system of mirrors. By performing transverse-momentum sampling interference between polarization-entangled pairs of photons that propagate with different momenta, we show that it is possible to perform transverse-displacement estimation with a precision that increases with the difference of the transverse momenta of the photons. Moreover, we show that for the estimation of small displacements, it is possible to simplify the measurement scheme replacing the transverse-momentum resolving detectors with bucket detectors without any loss in sensitivity. More fundamentally, we demonstrate that it is the quantum interference arising from two-photon entanglement in the transverse momenta at the very heart of the foreseen quantum-limited sensitivity in the spatial domain.Comment: 5 pages, 3 figure

Serum Testosterone and Cognitive Function in Ageing Male: Updating the Evidence.

Background: Testosterone (T) deficit, either in prepubertal or postpubertal form of hypogonadism, seems to play a key role in impairing cognitive function, including memory, attention, language and visuospatial abilities, especially in elderly men. Objective: Several studies have recently showed the association between low serum T levels and important cognitive dysfunctions in ageing male as well as in subjects suffering from Alzheimer’s disease (AD), mild cognitive impairment (MCI) and even depression, suggesting that T could exert an active neuroprotective role. Methods: By searching PubMed and recent patents (ranging from 2010 to 2015), we identified several observational and intervention studies dealing with T and cognitive function in adult and ageing men. Findings were reviewed, thoroughly examined and, finally, summarized herein. Results: Although a large number of studies have been carried out so far, conclusive evidence cannot be drawn, in par-ticular, for cognitive disorders in males. Conversely, T supplementation has been suggested for depressive syndrome in young and ageing men. To date, no clinical data have been carried out on cognitive dysfunctions employing the quoted patents in men. Conclusions: Studies aiming to evaluate the role of serum T and its supplementation in adult and ageing men with T defi-ciency syndrome need to be encouraged, given that subjects affected by overt hypogonadism, either in prepubertal (i.e. Klinefelter syndrome) or postpubertal forms (chemical castration in subjects affected by prostate cancer), often complain of cognitive dysfunction, and seem to considerably benefit from T replacement therapy

Assessment of Burnout Levels before and during COVID-19 Pandemic: A Web-Based Survey by the (Italian) Association of Medical Endocrinologists (AME)

Background: Some endocrinologists were involved in the management of patients with suspected or confirmed COVID-19 during the first wave of the pandemic. This study aims to analyze burnout levels among the Association of Medical Endocrinologists (AME) members before and during the pandemic. Methods: We recruited two AME members samples at two different times: before COVID-19 (n = 811) and during the first wave of the ongoing pandemic (n = 579). Both the samples filled the Maslach Burnout Inventory. We performed MANOVAs to evaluate demographic and COVID-19 related differences in burnout levels and Pearson's Chi-square test to compare burnout severity before and during the pandemic. Results: Women reported higher Emotional Exhaustion and reduced Professional Accomplishment than men. The oldest physicians had lower levels of Emotional Exhaustion and Depersonalization and higher Professional Accomplishment than younger workers. Independent contractors displayed lower levels of burnout compared to established contractors. Finally, the pandemic, per se, did not lead to changes in burnout levels. Discussion: Women and young physicians are at higher risk of burnout. It is also possible that front- line professionals are at higher risk during a health care crisis. Moreover, it is likely that the length of exposure to the pandemic has not been sufficient to impact burnout levels. Conclusion: Short-term exposure to pandemic-related activities seemed to have a low impact on burnout severity, except for physicians directly involved in managing COVID-19 cases. It is strongly recommended the availability of psychological support in public hospitals

Distance sensing emerging from second-order interference of thermal light

We introduce and describe a technique for distance sensing, based on second-order interferometry of thermal light. The method is based on measuring correlation between intensity fluctuations on two detectors, and provides estimates of the distances separating a remote mask from the source and the detector, even when such information cannot be retrieved by first-order intensity measurements. We show how the sensitivity to such distances is intimately connected to the degree of correlation of the measured interference pattern in different experimental scenarios and independently of the spectral properties of light. Remarkably, this protocol can be also used to measure the distance of remote reflective objects in the presence of turbulence. We demonstrate the emergence of new critical parameters which benchmark the degree of second-order correlation, describing the counterintuitive emergence of spatial second-order interference not only in the absence of (first-order) coherence at both detectors but also when first order interference is observed at one of the two detectors.Comment: 6 pages, 3 figure

Para- and perirenal ultrasonographic fat thickness is associated with 24-hours mean diastolic blood pressure levels in overweight and obese subjects

BACKGROUND: Renal sinus fat (RSF) has been recognized as a risk factor for arterial hypertension. This study was addressed to examine whether also para- and perirenal fat accumulation is associated to higher 24-h mean systolic (SBP) and/or diastolic blood pressure (DBP) levels in overweight and obese subjects. METHODS: A cohort of 42 overweight and obese patients, 29 women and 13 men, aged 25-55 years, not treated with any kind of drug, was examined. Body mass index (BMI), waist circumference (WC), fasting insulin and glucose serum levels, insulin resistance (assessed by using the homeostasis model assessment [HOMAIR]), and 24-h aldosterone urine levels were measured. Ambulatory blood pressure monitoring (ABPM) was measured with 15 min intervals from 7.0 a.m. to 11.0 a.m. and with 30 min intervals from 23.0 to 7.0 for consecutive 24 h, starting from 8:30 AM. Measurement of para- and perirenal fat thickness was performed by ultrasounds by a duplex Doppler apparatus. RESULTS: Para- and perirenal ultrasonographic fat thickness (PUFT) was significantly and positively correlated with WC (p < 0.01), insulin (p < 0.01), HOMAIR (p < 0.01), and 24-h mean DBP levels (p < 0.05). 24-h mean DBP was also significantly and positively correlated with 24-h aldosterone urine concentrations (p < 0.001). A multivariate analysis by multiple linear regression was performed; the final model showed that the association of 24-h mean DBP as dependent variable with PUFT (multiple R = 0.34; p = 0.026) and daily aldosterone production (multiple R = 0.59; p = 0.001) was independent of other anthropometric, hormone and metabolic parameters. DISCUSSION AND CONCLUSIONS: This study shows a positive independent association between PUFT and mean 24-h diastolic blood pressure levels in overweight and obese subjects, suggesting a possible direct role of PUFT in increasing daily diastolic blood pressure