1,872 research outputs found

    Consumer Preferences for Fruit and Vegetables with Credence-Based Attributes: A Review

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    credence goods, consumer preferences and attitudes, sustainable fruit and vegetables, consumer research., Agricultural Finance, Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Institutional and Behavioral Economics, Marketing, Productivity Analysis,

    Guidelines for physical weed control research: flame weeding, weed harrowing and intra-row cultivation

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    A prerequisite for good research is the use of appropriate methodology. In order to aggregate sound research methodology, this paper presents some tentative guidelines for physical weed control research in general, and flame weeding, weed harrowing and intra-row cultivation in particular. Issues include the adjustment and use of mechanical weeders and other equipment, the recording of impact factors that affect weeding performance, methods to assess effectiveness, the layout of treatment plots, and the conceptual models underlying the experimental designs (e.g. factorial comparison, dose response). First of all, the research aims need to be clearly defined, an appropriate experimental design produced and statistical methods chosen accordingly. Suggestions on how to do this are given. For assessments, quantitative measures would be ideal, but as they require more resources, visual classification may in some cases be more feasible. The timing of assessment affects the results and their interpretation. When describing the weeds and crops, one should list the crops and the most abundantly present weed species involved, giving their density and growth stages at the time of treatment. The location of the experimental field, soil type, soil moisture and amount of fertilization should be given, as well as weather conditions at the time of treatment. The researcher should describe the weed control equipment and adjustments accurately, preferably according to the prevailing practice within the discipline. Things to record are e.g. gas pressure, burner properties, burner cover dimensions and LPG consumption in flame weeding; speed, angle of tines, number of passes and direction in weed harrowing. The authors hope this paper will increase comparability among experiments, help less experienced scientists to prevent mistakes and essential omissions, and foster the advance of knowledge on non-chemical weed management

    Memory beyond memory in heart beating: an efficient way to detect pathological conditions

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    We study the long-range correlations of heartbeat fluctuations with the method of diffusion entropy. We show that this method of analysis yields a scaling parameter δ\delta that apparently conflicts with the direct evaluation of the distribution of times of sojourn in states with a given heartbeat frequency. The strength of the memory responsible for this discrepancy is given by a parameter ϵ2\epsilon^{2}, which is derived from real data. The distribution of patients in the (δ\delta, ϵ2\epsilon^{2})-plane yields a neat separation of the healthy from the congestive heart failure subjects.Comment: submitted to Physical Review Letters, 5 figure

    Headache and pregnancy. a systematic review

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    This systematic review summarizes the existing data on headache and pregnancy with a scope on clinical headache phenotypes, treatment of headaches in pregnancy and effects of headache medications on the child during pregnancy and breastfeeding, headache related complications, and diagnostics of headache in pregnancy. Headache during pregnancy can be both primary and secondary, and in the last case can be a symptom of a life-threatening condition. The most common secondary headaches are stroke, cerebral venous thrombosis, subarachnoid hemorrhage, pituitary tumor, choriocarcinoma, eclampsia, preeclampsia, idiopathic intracranial hypertension, and reversible cerebral vasoconstriction syndrome. Migraine is a risk factor for pregnancy complications, particularly vascular events. Data regarding other primary headache conditions are still scarce. Early diagnostics of the disease manifested by headache is important for mother and fetus life. It is especially important to identify "red flag symptoms" suggesting that headache is a symptom of a serious disease. In order to exclude a secondary headache additional studies can be necessary: electroencephalography, ultrasound of the vessels of the head and neck, brain MRI and MR angiography with contrast ophthalmoscopy and lumbar puncture. During pregnancy and breastfeeding the preferred therapeutic strategy for the treatment of primary headaches should always be a non-pharmacological one. Treatment should not be postponed as an undermanaged headache can lead to stress, sleep deprivation, depression and poor nutritional intake that in turn can have negative consequences for both mother and baby. Therefore, if non-pharmacological interventions seem inadequate, a well-considered choice should be made concerning the use of medication, taking into account all the benefits and possible risks

    Commissioning of the MEG II tracker system

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    The MEG experiment at the Paul Scherrer Institut (PSI) represents the state of the art in the search for the charged Lepton Flavour Violating (cLFV) μ+e+γ\mu^+ \rightarrow e^+ \gamma decay. With the phase 1, MEG set the new world best upper limit on the \mbox{BR}(\mu^+ \rightarrow e^+ \gamma) < 4.2 \times 10^{-13} (90% C.L.). With the phase 2, MEG II, the experiment aims at reaching a sensitivity enhancement of about one order of magnitude compared to the previous MEG result. The new Cylindrical Drift CHamber (CDCH) is a key detector for MEG II. CDCH is a low-mass single volume detector with high granularity: 9 layers of 192 drift cells, few mm wide, defined by 12000\sim 12000 wires in a stereo configuration for longitudinal hit localization. The filling gas mixture is Helium:Isobutane (90:10). The total radiation length is 1.5×1031.5 \times 10^{-3} \mbox{X}_0, thus minimizing the Multiple Coulomb Scattering (MCS) contribution and allowing for a single-hit resolution <120< 120 μ\mum and an angular and momentum resolutions of 6 mrad and 90 keV/c respectively. This article presents the CDCH commissioning activities at PSI after the wiring phase at INFN Lecce and the assembly phase at INFN Pisa. The endcaps preparation, HV tests and conditioning of the chamber are described, aiming at reaching the final stable working point. The integration into the MEG II experimental apparatus is described, in view of the first data taking with cosmic rays and μ+\mu^+ beam during the 2018 and 2019 engineering runs. The first gas gain results are also shown. A full engineering run with all the upgraded detectors and the complete DAQ electronics is expected to start in 2020, followed by three years of physics data taking.Comment: 10 pages, 12 figures, 1 table, proceeding at INSTR'20 conference, accepted for publication in JINS

    Male and female sex hormones in primary headaches

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    Background: The three primary headaches, tension-type headache, migraine and cluster headache, occur in both genders, but all seem to have a sex-specific prevalence. These gender differences suggest that both male and female sex hormones could have an influence on the course of primary headaches. This review aims to summarise the most relevant and recent literature on this topic. Methods: Two independent reviewers searched PUBMED in a systematic manner. Search strings were composed using the terms LH, FSH, progesteron, estrogen, DHEA, prolactin, testosterone, androgen, headach, migrain, "tension type" or cluster. A timeframe was set limiting the search to articles published in the last 20 years, after January 1st 1997. Results: Migraine tends to follow a classic temporal pattern throughout a woman's life corresponding to the fluctuation of estrogen in the different reproductive stages. The estrogen withdrawal hypothesis forms the basis for most of the assumptions made on this behalf. The role of other hormones as well as the importance of sex hormones in other primary headaches is far less studied. Conclusion: The available literature mainly covers the role of sex hormones in migraine in women. Detailed studies especially in the elderly of both sexes and in cluster headache and tension-type headache are warranted to fully elucidate the role of these hormones in all primary headaches

    Displacement power spectrum measurement of a macroscopic optomechanical system at thermal equilibrium

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    The mirror relative motion of a suspended Fabry-Perot cavity is studied in the frequency range 3-10 Hz. The experimental measurements presented in this paper, have been performed at the Low Frequency Facility, a high finesse optical cavity 1 cm long suspended to a mechanical seismic isolation system identical to that one used in the VIRGO experiment. The measured relative displacement power spectrum is compatible with a system at thermal equilibrium within its environmental. In the frequency region above 3 Hz, where seismic noise contamination is negligible, the measurement distribution is stationary and Gaussian, as expected for a system at thermal equilibrium. Through a simple mechanical model it is shown that: applying the fluctuation dissipation theorem the measured power spectrum is reproduced below 90 Hz and noise induced by external sources are below the measurement.Comment: 11 pages, 9 figures, 2 tables, to be submitte

    Design, status and perspective of the Mu2e crystal calorimeter

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    The Mu2e experiment at Fermilab will search for the charged lepton flavor violating process of neutrino-less μe\mu \to e coherent conversion in the field of an aluminum nucleus. Mu2e will reach a single event sensitivity of about 2.510172.5\cdot 10^{-17} that corresponds to four orders of magnitude improvements with respect to the current best limit. The detector system consists of a straw tube tracker and a crystal calorimeter made of undoped CsI coupled with Silicon Photomultipliers. The calorimeter was designed to be operable in a harsh environment where about 10 krad/year will be delivered in the hottest region and work in presence of 1 T magnetic field. The calorimeter role is to perform μ\mu/e separation to suppress cosmic muons mimiking the signal, while providing a high level trigger and a seeding the track search in the tracker. In this paper we present the calorimeter design and the latest R&\&D results.Comment: 4 pages, conference proceeding for a presentation held at TIPP'2017. To be published on Springer Proceedings in Physic

    Quality Assurance on a custom SiPMs array for the Mu2e experiment

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    The Mu2e experiment at Fermilab will search for the coherent μe\mu \to e conversion on aluminum atoms. The detector system consists of a straw tube tracker and a crystal calorimeter. A pre-production of 150 Silicon Photomultiplier arrays for the Mu2e calorimeter has been procured. A detailed quality assur- ance has been carried out on each SiPM for the determination of its own operation voltage, gain, dark current and PDE. The measurement of the mean-time-to-failure for a small random sample of the pro-production group has been also completed as well as the determination of the dark current increase as a function of the ioninizing and non-ioninizing dose.Comment: 4 pages, 10 figures, conference proceeding for NSS-MIC 201

    Crises and collective socio-economic phenomena: simple models and challenges

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    Financial and economic history is strewn with bubbles and crashes, booms and busts, crises and upheavals of all sorts. Understanding the origin of these events is arguably one of the most important problems in economic theory. In this paper, we review recent efforts to include heterogeneities and interactions in models of decision. We argue that the Random Field Ising model (RFIM) indeed provides a unifying framework to account for many collective socio-economic phenomena that lead to sudden ruptures and crises. We discuss different models that can capture potentially destabilising self-referential feedback loops, induced either by herding, i.e. reference to peers, or trending, i.e. reference to the past, and account for some of the phenomenology missing in the standard models. We discuss some empirically testable predictions of these models, for example robust signatures of RFIM-like herding effects, or the logarithmic decay of spatial correlations of voting patterns. One of the most striking result, inspired by statistical physics methods, is that Adam Smith's invisible hand can badly fail at solving simple coordination problems. We also insist on the issue of time-scales, that can be extremely long in some cases, and prevent socially optimal equilibria to be reached. As a theoretical challenge, the study of so-called "detailed-balance" violating decision rules is needed to decide whether conclusions based on current models (that all assume detailed-balance) are indeed robust and generic.Comment: Review paper accepted for a special issue of J Stat Phys; several minor improvements along reviewers' comment
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