A novel mechanism to produce and detect light dark matter in experiments making use of GeV electrons (and positrons) impinging on a thick target (beam dump) is proposed. The positron-rich environment ...produced by the electromagnetic shower allows us to produce an A^{'} via nonresonant (e^{+}+e^{-}→γ+A^{'}) and resonant (e^{+}+e^{-}→A^{'}) annihilation on atomic electrons. The latter mechanism, for some selected kinematics, results in a larger sensitivity with respect to limits derived by the commonly used A^{'}-strahlung. This idea, applied to beam-dump experiments and active beam-dump experiments, pushes down the current limits by an order of magnitude.
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High-energy positron annihilation is a viable mechanism to produce dark photons (A′). This reaction plays a significant role in beam-dump experiments using multi-GeV electron beams on thick targets ...by enhancing the sensitivity to A′ production. The positrons produced by the electromagnetic shower can produce an A′ via nonresonant (e++e−→γ+A′) and resonant (e++e−→A′) annihilation on atomic electrons. For visible decays, the contribution of resonant annihilation results in a larger sensitivity with respect to limits derived by the commonly used A′-strahlung in certain kinematic regions. When included in the evaluation of the E137 beam-dump experiment reach, positron annihilation pushes the current limit on ϵ downwards by a factor of 2 in the range 33 MeV/c2<mA′<120 MeV/c2.
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While accelerator particle physics has traditionally focused on exploring dark matter through highenergy experiments, testing dark-sectors hypothesis requires innovative low energy experiments that ...use highintensity beams and high-sensitivity detectors. In this scenario attractive opportunities are offered to low energy machines and flavour experiments. In this paper we will focus our attention on the Dark Photon (DP) scenario, reviewing the current status of searches and new opportunities with particular attention to the PADME experiment at Laboratori Nazionali di Frascati.
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The PADME experiment at LNF Raggi, M; Kozhuharov, V; Valente, P
EPJ Web of Conferences,
2015, Volume:
96
Journal Article, Conference Proceeding
Peer reviewed
Open access
Massive photon-like particles are predicted in many extensions of the Standard Model. They have interactions similar to the photon, are vector bosons, and can be produced together with photons. The ...PADME experiment proposes a search for the dark photon (A′) in the e+ e− → γA′ process in a positron-on-target experiment, exploiting the positron beam of the DAΦNE linac at the Laboratori Nazionali di Frascati, INFN. In one year of running a sensitivity in the relative interaction strength down to 10−6 is achievable, in the mass region from 2.5 MeV < MA′ < 22.5 MeV. The proposed experimental setup and the analysis technique is discussed.
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Emblica officinalis Gaertn. is one of the most important plants of Āyurved, the traditional Indian medicine. In this ancient medicine, the fruit of Emblica officinalis is processed according to a ...method named “Svaras Bhavana”, whereby the therapeutic potential of the plant is enhanced by treating the main herb with its own juice. For many years, the activity of the fruits was attributed to the high content of ascorbic acid; however, this has recently been questioned. The aim of the paper is to clarify this matter. A reliable and feasible HPLC method with diode array detection has been developed for the determination of ascorbic acid in Emblica fruit and particularly in Emblica fruit processed according to the Ayurvedic method. The antioxidant effects have also been evaluated in comparison to the real levels of Vitamin C by different antioxidant tests. The data obtained show that the Emblica fruit contains ascorbic acid (0.40%, w/w), and that the Ayurvedic method of processing increases the healthy characteristics of the fruit thanks to a higher antioxidant activity and a higher content of ascorbic acid (1.28%, w/w). It has also been found that Vitamin C accounts for approximately 45–70% of the antioxidant activity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The aim of the study was the development of analytical methods suitable for the quantification of
l-dopa, carbidopa and entacapone in plasma of Parkinsonian patients treated with Stalevo
®. The ...metabolite 3-
O-methyldopa was also determined to obtain some indications on the pharmacokinetics of
l-dopa.
For the simultaneous analysis of
l-dopa, 3-
O-methyldopa and carbidopa, a RP C18 column as the stationary phase and a mixture of methanol and a pH 2.88 phosphate buffer (8:92, v/v) as the mobile phase were used. A feasible plasma pre-treatment based on protein precipitation was implemented, obtaining extraction yield higher than 94% for all the analytes. For the analysis of entacapone a RP C8 column and a mixture of methanol, acetonitrile and a pH 1.90 phosphate buffer as the mobile phase (17.5:22.5:60, v/v/v) were used. A plasma pre-treatment procedure was developed, based on solid phase extraction of entacapone using Oasis HLB cartridges. Extraction yields were good, being always higher than 96%.
Both methods, based on HPLC–ED (
V
=
+0.8
V), have been fully validated. Good linearity was obtained over the following concentration ranges: 100–4000
ng
mL
−1 for
l-dopa, 200–10,000
ng
mL
−1 for 3-
O-methyldopa, 25–4000
ng
mL
−1 for carbidopa and 20–4000
ng
mL
−1 for entacapone. Precision data were satisfactory, being R.S.D.% values lower than 5.64%; accuracy also resulted very good with recovery data higher than 90%. The proposed methods have been successfully applied to the analysis of patient plasma samples and seem to be suitable for therapeutic drug monitoring purposes.
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7.
The PADME experiment at LNF Raggi, M.
EPJ Web of Conferences,
01/2017, Volume:
142
Journal Article, Conference Proceeding
Peer reviewed
Open access
The PADME experiment, approved by INFN at the end of 2015, aims to search for missing mass signals in the annihilation of positrons on a thin fixed target produced by invisible decays of the dark ...photon. The detector construction will be completed by the end of 2017 to be ready to run in spring of 2018. The collaboration aims at collecting about 1013 positron on target by the end of 2018 to reach a sensitivity down to 1 × 10−3 on the coupling of A′ up to 23.7 MeV mass.
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The aim of this paper was to investigate the subjective responses of abstinent heroin users to both neutral and negative stimuli and the related hypothalamus-pituitary-adrenal reactions to emotional ...experience in relationship to their perception of childhood adverse experiences. Thirty male abstinent heroin dependents were included in the study. Emotional responses and childhood neglect perception were measured utilizing the State-Trait Anxiety Inventory Y-1 and the Child Experience of Care and Abuse Questionnaire. Neutral and unpleasant pictures selected from the International Affective Picture System and the Self-Assessment Manikin procedure have been used to determine ratings of pleasure and arousal. These ratings were compared with normative values obtained from healthy volunteers used as control. Blood samples were collected before and after the experimental sessions to determine both adrenocorticotropic hormone and cortisol plasma levels. Basal anxiety scores, cortisol and adrenocorticotropic hormone levels were higher in abstinent heroin users than in controls. Tests showed that anxiety scores did not change in controls after the vision of neutral slides, whilst they did in abstinent heroin addicts, increasing significantly; and increased less significantly after the unpleasant task, in comparison to controls. Abstinent heroin users showed significantly higher levels of parent antipathy and childhood emotional neglect perception than controls for both the father and the mother. Plasma adrenocorticotropic hormone and cortisol levels did not significantly increase after unpleasant slide set viewing among addicted individuals, because of the significantly higher basal levels characterizing the addicted subjects in comparison with controls. Multiple regression correlation showed a significant relationship between childhood neglect perception, arousal reaction, impaired hypothalamus-pituitary-adrenal axis response and addiction severity. Early adverse experiences seem to affect the entire interaction between hyper-arousal, reduced hormonal response to stress and addiction severity. Our findings, although obtained in a small number of subjects, indicate a significant link between the perception of parental style/care/support during childhood and the ability to cope with stressful emotional stimuli in adulthood and addiction severity.
•Addicted subjects react to emotions with higher arousal but week HPA axis response.•Addiction severity seems to be related to the childhood adverse experiences.•Emotional impairment seems to link childhood neglect and addiction behaviour.
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The integrated low-level trigger and data acquisition (TDAQ) system of the NA62 experiment at CERN is described. The requirements of a large and fast data reduction in a high-rate environment for a ...medium-scale, distributed ensemble of many different sub-detectors led to the concept of a fully digital integrated system with good scaling capabilities. The NA62 TDAQ system is rather unique in allowing full flexibility on this scale, allowing in principle any information available from the detector to be used for triggering. The design concept, implementation and performances from the first years of running are illustrated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Regional priorities are significant in affecting the participation in measure 214.•Spatial component are significant in improving the explanatory ability of the model.•Explanatory variables were ...sharply differentiated by sub-measures.
The objective of the paper is to understand the determinants of the spatial location of participation in Agri-Environmental Schemes and, in particular, to understand the interplay between structural determinants, priority criteria and spillover effects in guiding participation. As a first step, the paper seeks to conceptualise the issue based on the existing literature. Thereafter, an econometric model is used to provide an empirical application on data regarding participation in measure 214 of the Rural Development Programme 2007–2013 in an Italian region (Emilia-Romagna). The results show that both priority scores and the spatial dimension are significant in affecting participation.
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