1,721,271 research outputs found
The influence of the shape on the acoustical performance of classrooms
No full textThe classrooms should have short RTs (0,4-0,6 s) and high speech intelligibility rating, but many existing classrooms have RTs of one seconds or more as well as a non uniform acoustic field: this interferes with speech intelligibility, resulting in reduced understanding. The paper reports the influence of the shape and the absorption surfaces distribution on the acoustical performances of the classrooms. The main acoustical parameters was measured in several classrooms with various length ratios and spaciousness. The analysis considers the classrooms obtained from rooms intended for other use: classroom obtained putting together two or three offices and classroom obtained from the restoration of a warehouse. In order to take the acoustical field, in each classroom, in several position of the microphone, was measured the impulse response using a computer based MLS measurement system. The calculation of the EOT and Reverberation Time (T15 e T30) through Schroeder's backward integration of the impulse responses and the calculation of same physical describes as Clarity (C50 and C80), Definition, EOT, RT, STI and RASTI were carried out. The analysis pointed out the limits in the restoration of rooms intended for classrooms in order to advise rules in the classroom's design and in the restorations
Prospects for Higgs properties determination at the LHC
No full textThe strategies recently developed to study Higgs boson properties at the LHC are reviewed. It is shown how to obtain model-independent determinations of couplings to fermions and gauge bosons by exploiting different production and decay channels. We consider in some detail the case of weak boson fusion Higgs production with H to bb as well as the prospects for the determination of the Higgs self- coupling at the SLHC. (22 refs)
Photoactive sol-gel hybrid coatings from modified fluorocarbon polymers and amorphous titania
No full textA series of organic???inorganic hybrid coatings was prepared through sol???gel chemistry by combining
silanized chlorotrifluoroethylene-vinylether (FEVE) binders with tetraalkoxy silicon and titania sols
under acidic conditions. The best compositions to obtain highly transparent and homogeneous coatings
after thermal curing were determined. All the hybrid coatings easily pass the MEK test and show high
scratch hardness. The atomic force microscopy (AFM) shows the formation of very smooth surfaces (Rrms
routinely <1 nm) without clear phase separation phenomena. The typical size of the ???objects??? which may
be individuated is in the range of 40???80 nm. Wettability through contact angle measurements shows
the formation of moderately hydrophobic surfaces with a low contact angle hysteresis (???20???) which
is a further indication of very smooth, homogeneous and chemically stable surfaces. After irradiation
with UV-B light only hybrid coatings containing titania phases show a significant switch to a superhydrophilic
behavior with a contact angle against H2O down to 6???, which is only partially recovered
after storage of the material in the dark. Titania based hybrid coatings also showed a fast and efficient
UV-induced discoloration of the resazurin ink. The formulation of the coatings with photostabilizers
belonging to the class of radical scavengers and UV absorbers does not change the photoinduced surface
properties while eliminating the yellowing of the coating after UV exposure. It is concluded that titaniafluoropolymer
hybrid coating show photoactivity and UV-induced superhydrophylicity mostly through
ionic mechanisms, which could be beneficial to develop high durability and self-cleaning protective
coatings
Chemical ripening of the cervix with intracervical application of sodium nitroprusside: a randomized controlled trial.
No full textNitric oxide (NO) has been found to be involved in the processes of cervical ripening. In a randomized, placebo-controlled study, cervical softening by an intracervical application of sodium nitroprusside, one of the most clinically potent and effective NO donor agents, was evaluated. A total of 36 primigravid women undergoing pregnancy termination between 9 and 12.5 weeks were enrolled. In one series, 18 patients were randomized to receive intracervically either placebo or 1\% nitroprusside gel (5 mg), followed by uterine evacuation 6 h after treatment. In another series, 18 patients received either placebo or 2\% nitroprusside gel (10 mg) into the cervical canal followed by uterine evacuation 3 h later. The cervical resistance, i.e. the force required to dilate the cervix from 3 to 10 mm, was the main outcome variable. It was recorded using a force sensing apparatus (dynamometer). Blood pressure was measured. Adverse events were recorded until 2 h after surgery. Women treated with both doses of nitroprusside gel showed values of cervical resistance significantly lower than those treated with placebo gel, at any tested diameter. No differences were found between subjects treated with the two different doses of nitroprusside. No significant consistent changes in blood pressure were induced by either dose of nitroprusside. No headaches were found in subjects treated with the NO donor. This study demonstrates that sodium nitroprusside applied into the cervical canal induces a rapid and significant softening of the cervix, thus reducing the force required to dilate it, compared with placebo-treated subjects. The chemical ripening of the cervix with sodium nitroprusside intracervical gel is an efficacious procedure in first-trimester pregnancy
H → γγ: a comment on the indeterminacy of non-gauge-invariant integrals
No full textWe reanalyze the recent computation of the amplitude of the Higgs boson decay into two photons presented by Gastmans et al. [1, 2]. The reasons for why this result cannot be the correct one have been discussed in some recent papers. We address here the general issue of the indeterminacy of integrals with four-dimensional gauge-breaking regulators and to which extent it might eventually be solved by imposing physical constraints. Imposing gauge invariance as the last step upon Rξ-gauge calculations with four-dimensional gauge-breaking regulators, allows us to recover the well known H→γγ result. However we show that in the particular case of the unitary gauge, the indeterminacy cannot be tackled in the same way. The combination of the unitary gauge with a cutoff regularization scheme turns out to be non-predictive. © 2013 Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd
Hypothalamic resetting at puberty and the sexual dimorphism of migraine.
No full textIt is well known that migraine is far more represented in females than in males. However, this gender-related difference is present only during reproductive life since in prepubertal children, migraine prevalence figures are independent of sex. Thus, transition to puberty accounts for changes which render females more susceptible to migraine attacks. In females, the main driver of the hormonal events allowing sexual maturation is the pulsatile secretion of hypothalamic LHRH modulated by opioid activity. Clinical reports suggest that migraine attacks could be prevented by the abolition of this neurohormonal secretion. On the other hand, several clinical and experimental observations have focused on neuroendocrine systems (opiatergic, serotonergic, adrenergic) as participating in the constitution of the so-called "migraine trait", the biological predisposition in patients that would explain their sensitivity to migraine triggers. Such neuroendocrine secretions are mainly dependent upon hypothalamic activity where a sexual dimorphic nucleus has been discovered in the preoptic area. We suggest that the sexual dimorphism of migraine should be sought in hypothalamic networks related to LHRH secretion
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
La città e la memoria patria : un secolo di storia del Museo del Risorgimento di Modena
No full textil saggio ricostruisce, attraverso il ricorso a materiale inedito d'archivio, la vicenda secolare del Museo del Risorgimento di Modena. La storia dell'istituzione culturale è inserita nel contesto della vita politica e culturale della città e nelle dinamiche della politica della memoria che hanno scandito lai rappresentazione della storia locale attraverso i vari allestimenti museali
- …
