Focusing and imaging with increased numerical apertures through multimode fibers with micro-fabricated optics

The use of individual multimode optical fibers in endoscopy applications has the potential to provide highly miniaturized and noninvasive probes for microscopy and optical micromanipulation. A few different strategies have been proposed recently, but they all suffer from intrinsically low resolution related to the low numerical aperture of multimode fibers. Here, we show that two-photon polymerization allows for direct fabrication of micro-optics components on the fiber end, resulting in an increase of the numerical aperture to a value that is close to 1. Coupling light into the fiber through a spatial light modulator, we were able to optically scan a submicrometer spot (300 nm FWHM) over an extended region, facing the opposite fiber end. Fluorescence imaging with improved resolution is also demonstrated.Comment: 5 pages, 3 figure

N=8 gaugings revisited: an exhaustive classification

In this paper we reconsider, for N=8 supergravity, the problem of gauging the most general electric subgroup. We show that admissible theories are fully characterized by a single algebraic equation to be satisfied by the embedding of the gauge group G within the electric subalgebra SL(8,\IR) of E_{7(7)}. The complete set of solutions to this equation contains 36 parameters. Modding by the action of SL(8,\IR) conjugations that yield equivalent theories all continuous parameters are eliminated except for an overall coupling constant and we obtain a discrete set of orbits. This set is in one--to--one correspondence with 36 Lie subalgebras of SL(8,\IR), corresponding to all possible real forms of the SO(8) Lie algebra plus a set of contractions thereof. By means of our analysis we establish the theorem that the N=8 gaugings constructed by Hull in the middle eighties constitute the exhaustive set of models. As a corollary we show that there exists a unique 7--dimensional abelian gauging. The corresponding abelian algebra is not contained in the maximal abelian ideal of the solvable Lie algebra generating the scalar manifold E_{7(7)}/SU(8).Comment: 1 LaTeX file, 41 pages, 3 eps-figure

Babies under 1 year with atypical development. Perspectives for preventive individuation and treatment

A baby's first year of life is a time of immense development and cerebral plasticity. Following today's research and clinical observation, the period of the first year of life provides a new challenge inasmuch it is presently clear that it is possible to identify developmental anomalies in this window of time. Effecting early screening procedures could prove very useful, especially where we find genetic vulnerabilities in brothers and sisters of autistic subjects. Interventions of this kind, already practiced by some Public Health systems, can mean taking early action and primary protective measures with significant impacts not only on the subjects (babies and family members) concerned, but also on the public purse. It is, therefore, essential to provide for specific professionalized procedures for psychologists, pediatricians and neuropsychologists to be introduced through personnel highly specialized in interventions during the first year of life

La discrezionalità amministrativa e l’autonomia privata davanti alla legge

[Abstract non presente

Diagnostic Delay in Oncology: A Case Report of Metastatic Seminoma

Germ cell tumours are the most common malignancy among young men; cryptorchidism is a possible risk factor for the development of testicular cancer. Psycho-oncology studies indicate that diagnostic delay can often be explained by different social conditions and that symptoms worsened under lack of appropriate treatment can lead to an urgent admission to the hospital. Nevertheless, germ cell tumours are considered curable malignancies even in advanced stages since the introduction of a chemotherapy regimen based on bleomycin, etoposide and cisplatin. Cell lines derived from germ cell tumours are sensitive to cisplatin-based treatment more than other solid cancers, which is reflected in the good clinical response. We report an unusual manifestation of malignancy in an adult man presenting with a metastatic seminoma of the left testicle. The large ulcerate and necrotic mass suggested a secondary infection from a tumour site. The patient reported surgical orchiopexy for left cryptorchidism in his childhood. Despite worsening of physical features, he had not sought help at the hospital for social reasons. The patient achieved complete clinical remission after receiving standard chemotherapy, and a good objective response of the primitive mass was clearly visible. Complete response was persistent at the 30-month clinical follow-up. The chemotherapy administration was later complicated by acute haemorrage in the site of the primitive tumour that needed urgent surgical management; in addition to this, the artificial graft material was rejected and the arterial prosthesis had to be removed

The Operator Product Expansion of N=4 SYM and the 4-point Functions of Supergravity

We give a detailed Operator Product Expansion interpretation of the results for conformal 4-point functions computed from supergravity through the AdS/CFT duality. We show that for an arbitrary scalar exchange in AdS(d+1) all the power-singular terms in the direct channel limit (and only these terms) exactly match the corresponding contributions to the OPE of the operator dual to the exchanged bulk field and of its conformal descendents. The leading logarithmic singularities in the 4-point functions of protected N=4 super-Yang Mills operators (computed from IIB supergravity on AdS(5) X S(5) are interpreted as O(1/N^2) renormalization effects of the double-trace products appearing in the OPE. Applied to the 4-point functions of the operators Ophi ~ tr F^2 + ... and Oc ~ tr FF~ + ..., this analysis leads to the prediction that the double-trace composites [Ophi Oc] and [Ophi Ophi - Oc Oc] have anomalous dimension -16/N^2 in the large N, large g_{YM}^2 N limit. We describe a geometric picture of the OPE in the dual gravitational theory, for both the power-singular terms and the leading logarithms. We comment on several possible extensions of our results.Comment: 42 page