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The helicity representation of the linear momentum density of a light wave is well understood for monochromatic optical fields in both paraxial and non-paraxial regimes of propagation. In this note we generalize such representation to nonmonochromatic optical fields. We find that, differently from the monochromatic case, the linear momentum density, aka the Poynting vector divided by c 2, does not separate into the sum of right-handed and left-handed terms, even when the so-called electricâ€"magnetic democracy in enforced by averaging the electric and magnetic contributions. However, for quasimonochromatic light, such a separation is approximately restored after time-averaging. This paper is dedicated to Sir Michael Berry on the occasion of his 80th birthday. [ABSTRACT FROM AUTHOR]

In paediatric coeliac disease (CD), symptoms may not be a reliable factor in the diagnosis of coeliac disease as described by Rosen et al,1 and thus, recommendations for reviewing CD screening criteria were suggested.2 Apart from the costs, an important limiting factor in paediatric population mass screening using conventional immunoglobulin (Ig) A tissue transglutaminase (tTGIgA) may be the low compliance of asymptomatic children to be referred for testing. In the first one, a cost of + 20% for POCT was used, while in the second one, to compare POCT screening strategy vs CF, a cost for each FP visit of €15.44 was added to every patient in the CF. For this reason, we suggest that paediatricians utilise POCT in asymptomatic children only and refer children with clinical suspicion of CD for undergoing conventional serology; otherwise, testing for CD might be slowed down by a negative POCT. [Extracted from the article]

Biofiltration systems are a promising retrofit option for site-constrained urban areas due to the vertical arrangement of treatment stages that leads to a relatively compact footprint. Existing knowledge about the influence of their design and configuration on hydrological, stormwater pollutant removal and long-term performance is limited and this has been identified as a barrier to their widespread uptake. Long-term simulations of lined and unlined biofiltration systems in four contrasting UK climatic regimes were used to assess the influence of climate, ponding depth, biofilter to drainage area ratio and infiltration rate on hydrological performance. The results showed that local differences in climate have a significant impact on performance and that infiltration rates as low as 0·36 mm/h are not suitable for locations in the UK with high rainfall unless the biofilter to drainage area ratio is greater than 10%. However, with higher infiltration rates (72 mm/h) a biofilter occupying only 3% of the impermeable catchment area would be capable of infiltrating 97% of annual rainfall in central England. Preliminary results of adsorption and column tests to assess the effectiveness of media amendments, specifically zeolite and granular activated carbon, for dissolved copper and phosphate removal are presented in this paper. [ABSTRACT FROM AUTHOR]

We address the question of whether there exists a hidden relationship between the near-field distribution generated by an oscillating electric dipole and the so-called cross-polarization of a collimated beam of light. We find that the answer is affirmative by showing that the complex field distributions occurring in both cases have a common physical origin: the requirement that the electromagnetic fields must be transverse. [ABSTRACT FROM AUTHOR]

The spin Hall effect of light (SHEL) is the photonic analogue of the spin Hall effect occurring for charge carriers in solid-state systems. This intriguing phenomenon manifests itself when a light beam refracts at an air-glass interface (conventional SHEL) or when it is projected onto an oblique plane, the latter effect being known as the geometric SHEL. It amounts to a polarization-dependent displacement perpendicular to the plane of incidence. In this work, we experimentally investigate the geometric SHEL for a light beam transmitted across an oblique polarizer. We find that the spatial intensity distribution of the transmitted beam depends on the incident state of polarization and its centroid undergoes a positional displacement exceeding one wavelength. This novel phenomenon is virtually independent from the material properties of the polarizer and, thus, reveals universal features of spin-orbit coupling. [ABSTRACT FROM AUTHOR]

Numerical evolutions of whispering gallery modes of both isotropic and anisotropic spheroidal resonators are presented and are used to build analytical approximations of these modes. Such approximations are carried out mainly to have the possibility to have manageable analytic formulas for the eigenmodes and eigenfrequencies of anisotropic resonators. A qualitative analysis of ellipsoidal anisotropic modes in terms of superposition of spherical modes is also presented. [ABSTRACT FROM AUTHOR]

The ABCD matrix formalism describing paraxial propagation of optical beams across linear systems is generalized to arbitrary beam trajectories. As a by-product of this study, a one-to-one correspondence between the extended ABCD matrix formalism presented here and the quantum mechanical translation operator is established. [ABSTRACT FROM AUTHOR]

A beam of light, reflected at a planar interface, does not follow perfectly the ray optics prediction. Diffractive corrections lead to beam shifts; the reflected beam is displaced (spatial Goos-Hänchen type shifts) and/or travels in a different direction (angular Imbert-Fedorov type shifts), as compared to geometric optics. How does the degree of spatial coherence of light influence these shifts? We investigate this issue first experimentally and find that the degree of spatial coherence influences the angular beam shifts, while the spatial beam shifts are unaffected. [ABSTRACT FROM AUTHOR]

We investigate how the orbital angular momentum of a paraxial light beam is affected upon reflection at a planar interface. Theoretically, the unavoidable angular spread of the beam leads to orbital angular momentum sidebands, which are found to be already significant for a modest beam spread (0.05). In analogy to the polarization Fresnel coefficients, we develop an analytical theory based upon spatial Fresnel coefficients; this allows a straightforward prediction of the strength of the sidebands. We confirm this by experiment and numerical simulation. [ABSTRACT FROM AUTHOR]

Two photons are said to be identical if they are prepared in the same quantum state. Given the latter, there is a unique way to achieve this. Conversely, there are many different ways of preparing two non-identical photons: they may differ in frequency, polarization, amplitude, etc. Therefore, photon distinguishability depends upon the specific degree of freedom being varied. By means of a careful analysis of the coincidence probability distribution in a Hong-Ou-Mandel experiment, we can show that photon distinguishability can be actually quantified by the rate of distinguishability of photons, an experimentally measurable parameter that crucially depends on both the photon quantum state and the degree of freedom under control [ABSTRACT FROM AUTHOR]

We present a graphical example of the interaction picture-time evolution. Our aim is to help students understand in a didactic manner the simplicity that this picture provides. Visualizing the interaction picture unveils its advantages, which are hidden behind the involved mathematics. Specifically, we show that the time evolution of a driven harmonic oscillator in the interaction picture corresponds to a local transformation of a phase space-reference frame into the one that is co-rotating with the Wigner function. [ABSTRACT FROM AUTHOR]

When a beam of light is reflected by a smooth surface its behavior deviates from geometrical optics predictions. Such deviations are quantified by the so-called spatial and angular Goos-Hänchen (GH) and Imbert-Fedorov (IF) shifts of the reflected beam. These shifts depend upon the shape of the incident beam, its polarization and on the material composition of the reflecting surface. In this paper we suggest a novel approach that allows one to unambiguously isolate the beam-shape dependent aspects of GH and IF shifts.We show that this separation is possible as a result of some universal features of shifted distribution functions which are presented and discussed. [ABSTRACT FROM AUTHOR]

An analytic solution for a uniaxial spherical resonator is presented using the method of Debye potentials. This serves as a starting point for the calculation of whispering gallery modes (WGMs) in such a resonator. Suitable approximations for the radial functions are discussed in order to best characterize WGMs. The characteristic equation and its asymptotic expansion for the anisotropic case is also discussed, and an analytic formula with a precision of the order O[v-1] is also given. Our careful treatment of both boundary conditions and asymptotic expansions makes the present work a particularly suitable platform for a quantum theory of whispering gallery resonators. [ABSTRACT FROM AUTHOR]

We derive a well-defined renormalized version of mutual information that allows us to estimate the dependence between continuous random variables in the important case when one is deterministically dependent on the other. This is the situation relevant for feature extraction, where the goal is to produce a low-dimensional effective description of a high-dimensional system. Our approach enables the discovery of collective variables in physical systems, thus adding to the toolbox of artificial scientific discovery, while also aiding the analysis of information flow in artificial neural networks. [ABSTRACT FROM AUTHOR]

The Schrödinger equation admits smooth and finite solutions that spontaneously evolve into a singularity, even for a free particle. This blowup is generally ascribed to the intrinsic dispersive character of the associated time evolution. We resort to the notion of quantum Bohmian trajectories to relate this singular behavior to local phase variations, which generate an underlying velocity field responsible for driving the quantum flux toward the singular region. • The dispersive blowup of the Schrödinger equation is investigated. • Local phase variations undergone by the wave function generate an underlying velocity field responsible for driving the quantum flux toward singular regions. • Bohmian trajectories are used to relate the wave function singular behavior to local phase variations. [ABSTRACT FROM AUTHOR]

Quantum approaches relying on entangled photons have been recently proposed to increase the efficiency of optical measurements. We demonstrate here that, surprisingly, the use of classical light with entangled degrees of freedom can also bring outstanding advantages over conventional measurements in polarization metrology. Specifically, we show that radially polarized beams of light allow to perform real-time single-shot Mueller matrix polarimetry. Our results also indicate that quantum optical procedures requiring entanglement without nonlocality can be actually achieved in the classical optics regime. [ABSTRACT FROM AUTHOR]

Due to the increasing mass mortality of Pinna nobilis, mainly caused by the protozoan Haplosporidium pinnae along the Mediterranean Sea, it is necessary to develop rapid and effective methods to detect the pathogen. The present study describes the development and validation of a species-specific assay based on hydrolysis probe chemistry to detect H. pinnae DNA from faeces and pseudofaeces of P. nobilis. During a study campaign in the Gulf of Trieste (Italy) in the spring and summer of 2022, 18 samples (10 faeces and 8 pseudofaeces) were collected. DNA was isolated from all samples and the presence of H. pinnae was tested by amplifying a small portion of 18S rDNA using qPCR. The newly developed assay detected positive H. pinnae in the faeces of the fan mussel in the spring, while no evidence of an outbreak of H. pinnae was found in the summer. In addition, the method proved to be noninvasive and can be used to monitor suspected H. pinnae infections in the early stages when bivalves are still vital. Furthermore, fecal analysis allows the monitoring of P. nobilis without dissecting tissues. The presented assay can also be used to routinely monitor the progress of mass mortalities caused by H. pinnae and to screen for the pathogen in live fan mussels and other environmental matrices, such as water, sediment, and faeces from other species that can host the protozoan. [ABSTRACT FROM AUTHOR]

We present precise expressions for the spatial and angular Goos–Hänchen and Imbert–Fedorov shifts experienced by a longitudinally and transversally limited beam of light (wavepacket) upon reflection from a dielectric interface, as opposed to the well-known case of a monochromatic beam which is bounded in transverse directions but infinitely extended along the direction of propagation. This is done under the assumption that the detector time is longer than the temporal length of the wavepacket (wavepacket regime). Our results will be applied to the case of a Gaussian wavepacket and show that, at the leading order in the Taylor expansion of reflected field amplitudes, the results are the same as in the monochromatic case. [ABSTRACT FROM AUTHOR]

Complete determination of the polarization state of light requires at least four distinct projective measurements of the associated Stokes vector. Stability of state reconstruction, however, hinges on the condition number k of the corresponding instrument matrix. Optimization of redundant measurement frames with an arbitrary number of analysis states, m, is considered in this Letter in the sense of minimization of k. The minimum achievable k is analytically found and shown to be independent of m, except for m = 5 where this minimum is unachievable. Distribution of the optimal analysis states over the Poincare sphere is found to be described by spherical 2 designs, including the Platonic solids as special cases. Higher order polarization properties also play a key role in nonlinear, stochastic, and quantum processes. Optimal measurement schemes for nonlinear measurands of degree t are hence also considered and found to correspond to spherical 21 designs, thereby constituting a generalization of the concept of mutually unbiased bases. [ABSTRACT FROM AUTHOR]

We generate tightly focused optical vector beams whose electric fields spin around an axis transverse to the beams' propagation direction. We experimentally investigate these fields by exploiting the directional near-field interference of a dipolelike plasmonic field probe placed adjacent to a dielectric interface. This directionality depends on the transverse electric spin density of the excitation field. Near- to far-field conversion mediated by the dielectric interface enables us to detect the directionality of the emitted light in the far field and, therefore, to measure the transverse electric spin density with nanoscopic resolution. Finally, we determine the longitudinal electric component of Belinfante's elusive spin momentum density, a solenoidal field quantity often referred to as "virtual." [ABSTRACT FROM AUTHOR]

We study the interaction of relativistic electron-vortex beams (EVBs) with laser light. Exact analytical solutions for this problem are obtained by employing the Dirac-Volkov wave functions to describe the (monoenergetic) distribution of the electrons in vortex beams with well-defined orbital angular momentum. Our new solutions explicitly show that the orbital angular momentum components of the laser field couple to the total angular momentum of the electrons. When the field is switched off, it is shown that the laser-driven EVB coincides with the field-free EVB as reported by Bliokh et al. [Phys. Rev. Lett. 107, 174802 (2011)]. Moreover, we calculate the probability density for finding an electron in the beam profile and demonstrate that the center of the beam is shifted with respect to the center of the field-free EVB. [ABSTRACT FROM AUTHOR]

We study the classical optics effects known as Goos–Hänchen and Imbert–Fedorov shifts, occurring when reflecting a bounded light beam from a planar surface, by using a quantum-mechanical formalism. This new approach allows us to naturally separate the spatial shift into two parts, one independent on orbital angular momentum (OAM) and the other one showing OAM-induced spatial-versus-angular shift mixing. In addition, within this quantum-mechanical-like formalism, it becomes apparent that the angular shift is proportional to the beams angular spread, namely to the variance of the transverse components of the wave vector. Moreover, we extend our treatment to the enhancement of beam shifts via weak measurements and relate our results to the recent experiments. [ABSTRACT FROM AUTHOR]

Background: The comparative costs of laparoscopy and laparotomy in surgical resection of colorectal cancer, especially of the hospital provider, have not yet been assessed in the perspective of the Italian National Healthcare System. This paper aims to fill this gap by providing economic information on this research topic of growing relevance at a time of reduced healthcare budgets. Methods: Three Italian reference centres retrospectively provided from their databases data on 90 cases of laparotomy (OP) or laparoscopy (LAP) interventions for right colon (RCol), left colon/sigma (LCol) and rectum (Rec). Costs were retrieved according to phases of the in-hospital procedure: pre-operative, operative and post-operative phase, including diagnostic work-up, hospital length of stay, duration of intervention, theatre occupation time, type of anaesthesia, medical devices and drugs used and staff time throughout the management process from hospital admission to discharge. The cost estimation was carried out using a microcosting, bottom-up technique, and statistical analysis was carried out using appropriate techniques. Results: The average cost of colorectal surgery was €10,539/patient (median €10,396) with rectum procedures being statistically more costly than colon procedures (mean Rec €12,562/patient versus LCol €9,054 and RCol €10,002; median €11,704 versus €8,941 and €9,513, respectively; p < 0.0001). The average cost per patient did not differ between the two procedures for colon interventions, whereas a statistically significant difference was found for rectum procedures (LAP €11,617 versus OP €13,506; median €11,563 versus €12,568; p = 0.0442). The national diagnosis related groups (DRG) tariff is insufficient to remunerate the providers' activity, irrespective of the type of disease (surgical site) and surgical technique adopted. Conclusion: Colorectal cancer surgery is a costly procedure, and in-patient DRG tariffs are currently insufficient to cover the cost of its management for Italian hospital providers. [ABSTRACT FROM AUTHOR]

Teleportation describes the transmission of information without transport of neither matter nor energy. For many years, however, it has been implicitly assumed that this scheme is of inherently nonlocal nature, and therefore exclusive to quantum systems. Here, we experimentally demonstrate that the concept of teleportation can be readily generalized beyond the quantum realm. We present an optical implementation of the teleportation protocol solely based on classical entanglement between spatial and modal degrees of freedom, entirely independent of nonlocality. Our findings could enable novel methods for distributing information between different transmission channels and may provide the means to leverage the advantages of both quantum and classical systems to create a robust hybrid communication infrastructure. [ABSTRACT FROM AUTHOR]

Scarce information is available about the cost of mobilisation/collection of peripheral blood stem cells for patients undergoing autologous transplant for relapsed Lymphoma or Multiple Myeloma. This paper reports the consumption of resources and costs collected through a survey among Italian Centres who adhere to the GITMO and SIdEM scientific societies. General transplant information was extracted from the European Promise database. Resources used alongside the phases of mobilisation/collection were retrieved. Resources for each of the process phases were quantified and averaged across centres and a unit cost value was attributed, based on administrative data from 3 centres, tariffs and market values. 25/89 Centres (34% of 2009 Promise transplants) provided data according to their standard practice. The mean cost/patient of the process of cell mobilisation/collection was €6830±1802 for Multiple Myeloma and €7304±1542 for Lymphoma. The organisational path for PBSC mobilisation/collection appears complex and cumbersome, spread amongst different treatment settings, with many different healthcare professionals being involved and considerable amounts of time and resources being currently dedicated to the management of patients requiring autologous transplantation. [ABSTRACT FROM AUTHOR]

We investigate how beams with orbital angular momentum (OAM) behave under total internal reflection. This is studied in two complementary experiments: in the first experiment, we study geometric shifts of OAM beams upon total internal reflection (Goos–Hänchen and Imbert–Fedorov shifts, for each the spatial and angular variant), and in the second experiment we determine changes in the OAM mode spectrum of a beam, again upon total internal reflection. As a result we find that, in the first case, the shifts are independent of OAM and beam focusing, while in the second case, modifications in the OAM spectrum occur which depend on the input OAM mode as well as on the beam focusing. This is investigated by experiment and theory. We also show how the two methods, beam shifts on the one hand, and OAM spectrum changes on the other, are related theoretically. [ABSTRACT FROM AUTHOR]

Background: The Internet may play a crucial role in the prompt provision of updated drug safety information. Nevertheless, limited knowledge of the English language among healthcare professionals or suboptimal search skills constitute barriers to widespread and appropriate use of the Internet for this purpose in Italy. In order to provide accurate information on drug safety and to promote the reporting of adverse drug reactions, in 1999 the clinical section of the Italian Society of Pharmacology created the website www.farmacovigilanza.org, financially supported by a non-profit foundation. The website promptly and independently provides news published in the international literature on drug safety, translated into Italian. The site also contains specific sections dedicated to adverse reactions to herbal products and cosmetic preparations.Objectives: The aim of this paper was to describe the number and characteristics of users and the most intensively visited sections of the website. Furthermore, in September 2006, 300 registered users who had accessed a registered users area aimed specifically at health professionals more than 20 times in the preceding 12 months received a ten-item multiple choice questionnaire via e-mail, to assess satisfaction with the accuracy and promptness of information provided, text comprehension and other information sources for drug-related issues. We hereby describe the results of the survey, after careful analysis of the questionnaires.Results: Up until July 2007, the site had over 600 000 direct accesses and 9760 healthcare professionals registered to use the site. A total of 108 responses to the e-mailed questionnaire were received (response rate = 36%), of which 103 were analysed; five were excluded due to missing information. Overall, the majority of responders judged the information on the site as objective and understandable. More than 85% of participants declared that the site has influenced their opinion and attitudes toward the safety of medicines. In particular, responders said that they pay more attention to drug interactions and to the safety profile of newly marketed drugs, and spend more time on communicating the risks of drugs used by their patients. Specifically, responders stated that they pay more attention to drug interactions (87.7%), newly marketed drugs (68.5%), herbal remedies (56.2%), drugs in patients at increased risk (42.5%), drugs in pregnant women (42.5%) and cosmetics (13.7%).Conclusions: The website www.farmacovigilanza.org appears to be an effective tool that provides users of the site with independent, relevant and reliable safety information. It was found to influence (and possibly improve) the quality of prescribing of a large proportion of the general practitioners who responded to our questionnaire, and our results indicate a high appreciation of the information found on the website. Moreover, the survey disclosed that there is a substantial need for such information in the national language by healthcare professionals. We think that our approach can serve as a model for similar initiatives in countries elsewhere in the world. [ABSTRACT FROM AUTHOR]

Biomarkers, especially CRP, have demonstrated their relevance to differentiate viral from bacterial infection, even though a reliable threshold is far to being found. In low- and middle-income countries, affordable and user-friendly rapid diagnostic tests based on biomarkers can be widely adopted to help health workers in the management of non-malarial fever. The primary objective of this study is to assess the best CRP cut-off to distinguish viral from bacterial infections. Other biomarkers were evaluated for the same purpose, alone or in combination with CRP. We retrospectively collected data from two referral hospital departments for infectious and tropical diseases in Italy. Areas under the ROC curve (AUC) were calculated and then compared using the DeLong test. Overall, we included 1193 febrile cases (viral 20.74% vs. bacterial 79.25%). We also collected malaria (n = 202) and intestinal parasite (n = 186) cases to establish their impact on biomarkers. CRP had the best accuracy in differentiating viral from bacterial infections. The best performance of CRP was a cut-off of 11 mg/L. All other biomarkers studied had significantly lower accuracy. Median CRP values were within the normal ranges in parasitic infections, while they were higher in malaria. None of the combinations of CRP with other biomarkers significantly increased the accuracy of CRP alone. [ABSTRACT FROM AUTHOR]