4,292 research outputs found
Optimal generation of entanglement under local control
We study the optimal generation of entanglement between two qubits subject to
local unitary control. With the only assumptions of linear control and unitary
dynamics, by means of a numerical protocol based on the variational approach
(Pontryagin's Minimum Principle), we evaluate the optimal control strategy
leading to the maximal achievable entanglement in an arbitrary interaction
time, taking into account the energy cost associated to the controls. In our
model we can arbitrarily choose the relative weight between a large
entanglement and a small energy cost.Comment: 4 page
b \bar b b\bar b production in proton-nucleus collisions at the LHC
A sizable rate of events, with several pairs of -quarks produced
contemporarily by multiple parton interactions, may be expected at very high
energies as a consequence of the large parton luminosities. The production
rates are further enhanced in hadron-nucleus reactions, which may represent a
convenient tool to study the phenomenon. We compare the different contributions
to production, due to single and double parton
scatterings, in collisions of protons with nuclei at the CERN-LHC.Comment: 13 pages, 4 figure
Fractional momentum correlations in multiple production of W bosons and of b-anti_b pairs in high energy pp collisions
Multiple parton collisions will represent a rather common feature in pp
collisions at the LHC, where regimes with very large momentum transfer may be
studied and events rare in lower energy accelerators might occur with a
significant rate. A reason of interest in large p_t regimes is that,
differently from low p_t, evolution will induce correlations in x in the
multiparton structure functions. We have estimated the cross section of
multiple production of W bosons with equal sign, where the correlations in x
induced by evolution are particularly relevant, and the cross section of
b-bar_b b-bar_b production, where the effects of evolution are much smaller.
Our result is that, in the case of multiple production of W bosons, the terms
with correlations may represent a correction of the order of 40% of the cross
sections, for pp collisions at 1 TeV c.m. energy, and a correction of the order
of 20% at 14 TeV. In the case of b-bar_b pairs the correction terms are of the
order of 10-15% at 1 TeV and of the order of 5% at 14 TeV.Comment: Submitted to Phys. Rev.
effect of dietary inclusion of flaxseed on milk yield and composition of dairy cows
The aim of the experiment was to study the effects of flaxseed inclusion on milk yield (MY), milk fat and protein contents and milk fatty acids (FA) composition in dairy cows diets. Eight Italian Friesian primiparous cows were divided into two homogeneous groups and fed a control diet (based on corn silage, fescue hay and a concentrate) or the same diet having 0.9 Kg DM concentrate replaced by coarsely grounded flaxseed for a 21 d experimental period. The groups were inverted in respect to the dietary treatments in a subsequent experimental period according to a change-over design. The flaxseed inclusion (4-5% DM) had a positive effect on dry matter intake (DMI, 22.2 vs. 21.3Kg/d) and significantly (P<0.01) increased the MY (26.9 vs. 26.1Kg/d) and milk fat corrected yield (FCM, 27.7 vs. 26.7Kg/d). Milk fat and protein percentages (4.18 and 3.46%, respectively on average) were not affected by flaxseed treatment. Results also indicated a significant (P<0.01) reduction of saturated fatty acid/unsaturated fatty acid ratio (SFA/UFA) and an increase of n-3/n-6FA, monounsaturated (MUFA) and polyunsaturated fatty acid (PUFA). Moreover a higher proportion of total C18:1 and conjugated linoleic acid isomers (CLA) was also observed for treated group
Possible explanations for different surface quality in laser cutting with 1 micron and 10 microns beams
In laserăcuttingăofăthickăsteelăsheets,ăqualityădifferenceăisăobservedăbetweenăcutăsurfacesăobtainedăwith 1 micron and 10 micron laser beams. This paper investigates physical mechanisms for this interesting and important problem of the wavelength dependence. First, striation generation process is described, based on a 3D structure of melt flow on a kerf front, which was revealed for the first time by our recent experimental observations. Two fundamental processes are suggested to explain the difference in the cut surface quality: destabilization of the melt flow in the central part of the kerf front and downward displacement of discrete melt accumulations along the side parts of the front. Then each of the processes is analyzed using a simplified analytical model. The results show that in both processes, different angular dependence of the absorptivity of the laser beam can result in the quality difference. Finally we propose use of radial polarization to improve the quality with the 1 micron wavelength
Language control and parallel recovery of language in individuals with aphasia
Background: The causal basis of the different patterns of language recovery following stroke in bilingual speakers is not well understood. Our approach distinguishes the representation of language from the mechanisms involved in its control. Previous studies have suggested that difficulties in language control can explain selective aphasia in one language as well as pathological switching between languages. Here we test the hypothesis that difficulties in managing and resolving competition will also be observed in those who are equally impaired in both their languages even in the absence of pathological switching.
Aims: To examine difficulties in language control in bilingual individuals with parallel recovery in aphasia and to compare their performance on different types of conflict task.
Methods & procedures: Two right-handed, non-native English-speaking participants who showed parallel recovery of two languages after stroke and a group of non-native English-speaking, bilingual controls described a scene in English and in their first language and completed three explicit conflict tasks. Two of these were verbal conflict tasks: a lexical decision task in English, in which individuals distinguished English words from non-words, and a Stroop task, in English and in their first language. The third conflict task was a non-verbal flanker task.
Outcomes & Results: Both participants with aphasia were impaired in the picture description task in English and in their first language but showed different patterns of impairment on the conflict tasks. For the participant with left subcortical damage, conflict was abnormally high during the verbal tasks (lexical decision and Stroop) but not during the non-verbal flanker task. In contrast, for the participant with extensive left parietal damage, conflict was less abnormal during the Stroop task than the flanker or lexical decision task.
Conclusions: Our data reveal two distinct control impairments associated with parallel recovery. We stress the need to explore the precise nature of control problems and how control is implemented in order to develop fuller causal accounts of language recovery patterns in bilingual aphasia
Zygomatic Implant Survival in 9 Ectodermal Dysplasia Patients with 3.5 to 7-year Follow Up
Ectodermal dysplasia syndrome is a complex group of genetic disorders identified by the abnormal development of the ectodermal structures. The aim of this retrospective clinical case series report was to evaluate the outcomes of the ectodermal dysplasia syndrome patients that underwent zygomatic implant surgery.
Materials and Methods: A total of 9 ectodermal dysplasia syndrome patients aged between 21 and 56 years (mean age 36.8) with severely atrophic maxilla were included in this study. All the patients were treated with a total of 19 zygomatic implants. The mean follow-up of the patients was 55 months (with a range of 44\u201384 months). The implant survival rate was evaluated as a primary outcome. The intra- and postoperative
complications were evaluated as additional criteria for success.
Results: The overall implant survival rate was 100% without any complications. Final or provisional prosthesis was delivered on the same day of surgery, which resulted in an improvement of the quality of life of the patients.
Conclusion: According to the results of this study, zygomatic surgery can be considered
as a viable and safe alternative to conventional treatment modalities for oral
rehabilitation of ectodermal dysplasia syndrome patients
Same-sign W pair production as a probe of double parton scattering at the LHC
We study the production of same-sign W boson pairs at the LHC in double
parton interactions. Compared with simple factorised double parton
distributions (dPDFs), we show that the recently developed dPDFs, GS09, lead to
non-trivial kinematic correlations between the W bosons. A numerical study of
the prospects for observing this process using same-sign dilepton signatures,
including same-sign WWjj, di-boson and heavy flavour backgrounds, at 14 TeV
centre-of-mass energy is then performed. It is shown that a small excess of
same-sign dilepton events from double parton scattering over a background
dominated by single scattering WZ(gamma*) production could be observed at the
LHC.Comment: 14 pages, 8 figures. Added references, slight changes in the text
Rare spontaneous monochorionic dizygotic twins: a case report and a systematic review
Background: Monochorionic dizygotic twins are a rare condition, mostly related to assisted reproductive technology. This type of twinning is burdened by the same risk of pregnancy complications found in monochorionic monozygotic pregnancies. Case presentation: We report a case of spontaneous monochorionic dizygotic twins sharing situs inversus abdominalis and isolated levocardia, with only one twin affected by biliary atresia with splenic malformation syndrome. We also conducted a literature review of the 14 available documented monochorionic dizygotic twin gestations spontaneously conceived. Conclusions: It is still unclear how this unusual type of twinning can occur in spontaneous conception. The evidence so far suggest the importance to timely diagnose the chorionicity, in order to adequately manage the typical complications associated with monochorionicity
Stuck Outside and Inside: An Exploratory Study on the Effects of the COVID-19 Outbreak on Italian Parents and Children\u2019s Internalizing Symptoms
The Covid-19 outbreak and the subsequent lockdown have profoundly impacted families\u2019 daily life, challenging their psychological resilience. Our study aimed to investigate the immediate psychological consequences of the pandemic on Italian parents and children focusing on internalizing and post-traumatic symptoms. We also wanted to explore the impact of possible risk and resilience factors, e.g., lifestyle and behaviors, emotional and cognitive beliefs, on parents and children\u2019s reaction to the emergency distress. An online survey was administered during the country\u2019s nationwide lockdown to 721 Italian parents of at least one child aged between 6 and 18 years. The respondent completed the survey for himself/herself and his/her child. The survey included socio-demographic items and validated questionnaires on parents\u2019 post-traumatic stress symptoms, depression and anxiety levels, and on children\u2019s internalizing problems. Parents were asked to fill the questionnaires twice: once referring to the current emergency condition and once recalling how they and their child felt a few months before Covid-19 outbreak. Multiple regression analyses showed that specific demographic characteristics (i.e., sex and age) and psychological factors of children and parents, such as fear of contagion and the opportunity to think about possible secondary positive effects of the pandemic, had a predictive value on the presence of internalizing symptoms of both parents and children. Moreover, parents\u2019 behaviors during the lockdown period (i.e., employment status and sport practiced) were significantly related to their own internalizing symptoms; these symptoms, in turn, had a strong and positive predictive value on children\u2019s internalizing problems. Besides, analyses of variance showed that internalizing symptoms of parents and children were significantly higher during the Covid-19 pandemic than before it started. In addition to showing a direct effect of the pandemic on the psychological health of parents and children, the present results also give a series of important information on how parents perceive, and therefore influence, their children in this period of emergency. Our findings thus highlight the urgent need to provide parents with adequate support to take care of their own psychological wellbeing and to help their children coping with the direct and indirect effects of the pandemic
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