Petrology, geochemistry and U-Pb zircon geochronology of lower crust pyroxenites from northen Apennine (Italy): insights into the post-collisional Variscan evolution

Spinel pyroxenites occur locally as clasts in polygenic breccias from the Late Cretaceous sedimentary melanges of the Northern Apennine (Italy). They are of cumulus origin and formed in the deep crust by early precipitation of clinopyroxene and minor olivine and late crystallisation of orthopyroxene, spinel, Ti-pargasite and sulphides. Pyroxenites underwent high-temperature (ca. 850 °C) subsolidus re-equilibration and ductile deformation with development of mylonitic bands made of clinopyroxene, orthopyroxene, Ti-pargasite and spinel. U-Pb geochronology on zircons revealed the occurrence of inherited grains of Early Proterozoic to Late Devonian age. The inherited zircons are locally rimmed by recrystallised zircon domains. The oldest rims yield a mean concordia U-Pb age at 306 ± 8 Ma, which is considered to date the emplacement of the pyroxenites, in the framework of the post-Variscan lithospheric extension. The incompatible element compositions of calculated melts in equilibrium with clinopyroxenes from the pyroxenites are characterised by Ba, Nb, LREE and Sr enrichment relative to N-MORB. The depleted Nd isotopic signature of the pyroxenites (initial εNd values of +5.3 to +6.1) may be thus linked to primary magmas produced by low degrees of melting of asthenospheric mantle. In addition, the pyroxenites locally record the infiltration of plagioclase-saturated hydrous melts, most likely evolved through fractional crystallisation and enriched in highly incompatible elements, within the clinopyroxene-dominated crystal mush. A thermal event in Late Permian-Middle Triassic caused the partial resetting of zircon U-Pb system

Clinical and Therapeutic Aspects of Vertigo

Abstract: Dizziness is a symptom frequently encountered in clinical practice, especially during emergency department visits and primary care visits. We can classify dizziness in one of four categories: vertigo, presyncope, disequilibrium and lightheadedness. Vertigo is the most common cause of dizziness and very often represents a diagnostic challenge for the clinician. Although appropriate clinical approach and history taking, the final diagnosis is unidentified in about 20 percent of the patients complaining of dizziness. The aim of this review is to provide an update on the main differential diagnoses of dizziness, with particular attention to the different otologic, vestibular and neurologic causes of vertigo, covering epidemiology, pathophysiology, clinical presentation, and therapy. We will discuss in detail the most common causes of vertigo, such as benign paroxysmal positional vertigo, labyrinthitis, Meniere's syndrome, vestibular neuritis, vestibular migraine and brainstem lesions. Special emphasis will be placed on the usefulness of diagnostic tests such as the Dix-Hallpike maneuver, the head impulse test and the electronystagmography. We will underline the need to perform a complete physical and neurological examination in order to correctly choose the appropriate diagnostic tests. Finally, we will review the different treatments currently available. It is extremely important to prescribe a proper treatment for dizziness, because this can dramatically improve the quality of life of these patients

Neurological diseases associated with autoantibodies targeting the voltage-gated potassium channel complex: immunobiology and clinical characteristics

Voltage-gated potassium channels (VGKCs) represent a group of tetrameric signaling proteins with several functions, including modulation of neuronal excitability and neurotransmitter release. Moreover, VGKCs give a key contribution to the generation of the action potential. VGKCs are complexed with other neuronal proteins, and it is now widely known that serum autoantibodies directed against VGKCs are actually directed against the potassium channel subunits only in a minority of patients. By contrast, these autoantibodies more commonly target three proteins that are complexed with alpha-dendrotoxin-labeled potassium channels in brain extracts. These three proteins are contactin-associated protein-2 (Caspr-2), leucine-rich, glioma inactivated 1 (LGI-1)-protein and the protein Tag-1/contactin-2. Neoplasms are detected only in a minority of seropositive patients for VGKC complex-IgG and do not significantly associate with Caspr-2 or LGI-1. Among all the cancers described in association with VGKC complex-IgG, lung carcinoma, thymoma, and hematologic malignancies are the most commonly detected. We will review all the major neurological conditions associated with VGKC complex-IgG. These include Isaacs’ syndrome, Morvan syndrome, limbic encephalitis, facio-brachial dystonic seizures, chorea and other movement disorders, epilepsy, psychosis, gastrointestinal neuromuscular diseases, a subacute encephalopathy that mimics Creutzfeldt-Jakob prion disease both clinically and radiologically and autoimmune chronic pain. The vast majority of these conditions are reversible by immunotherapy, and it is becoming increasingly recognized that early diagnosis and detection of VGKC complex-IgG is critical in order to rapidly start the treatment. As a result, VGKC complex-IgG are now part of the investigation of patients with unexplained subacute onset of epilepsy, memory or cognitive problems, or peripheral nerve hyperexcitability syndromes

Infrastrutture dei trasporti e città

In questo volume sono raccolti gli esiti del 6° Seminario Internazionale di Progettazione "Napoli, architettura e città". Eduard Bru, David Chipperfield, Max Dudler, Adolf Krischanitz, Christoph makler, Walter Arno Noebel hanno guidato i giovani architetti partecipanti nel progetto sulle aree degli svincoli del Vomero e dei Camaldoli della Tangenziale di Napoli. Il volume si conclude con i contributi di Kenneth Frampton e Robert Maxwell

La città di fondazione. Il quartiere di Monteruscello

I Seminari Internazionali di Progettazione "Napoli Architettura e Città" sono divenuti nel tempo una realtà importante nel panorama dei laboratori internazionali di progettazione. Questo volume documenta l'esperienza progettuale sul quartiere di Monteruscello -vera e propria città di fondazione- svolta da oltre cento giovani architetti guidati da Goncalo Byrne, Alberto Campo Baeza, David Chipperfield, Max Dudler, Luis Mateo e Jaques Sbriglio

Origin and timing of the post-Variscan gabbro-granite complex of Porto (Western Corsica)

The post-Variscan complex of Porto consists of metaluminous to slightly peraluminous A-type biotite granites mingled with gabbro-dioritic rocks, and late dykes with basaltic to trachyandesitic composition. U-Pb zircon dating by LA-ICP-MS on two mafic intrusive samples constrains the time of the gabbro-granite crystallisation at 281 ± 3 Ma and 283 ± 2 Ma. Hornblende 40Ar-39Ar ages from a late trachyandesite dyke date the dyking event at 280 ± 2 Ma, which is within error the U-Pb zircon ages of the intrusives. Biotite granites show variable major and trace element compositions and similar initial εNd (-0.3 to +0.9). Whole rock chemistry variations and trace element compositions of plagioclase and allanite indicate that the granites are genetically linked, essentially through fractional crystallisation of feldspars and minor allanite. On the basis of whole-rock chemistry (e.g. initial εNd +4.9 to +1.7) and trace element clinopyroxene compositions, we have ascertained that the mafic intrusives and basic dykes formed from isotopically depleted mantle source-derived melts with similar trace element signature. These basic melts experienced slightly different evolutionary histories, controlled by fractional crystallisation and crustal contamination, mainly by the acid magma that gave rise to the associated biotite granites, but also by the enclosing older Variscan granitoids. U-Pb zircon data suggest that the Porto complex was affected by hydrothermal fluid circulation at 259 ± 9 Ma