3,817 research outputs found

    Landscape Agency and Evenki-Iakut Reindeer Husbandry Along the Zhuia River, Eastern Siberia

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    This article is dedicated to the memory of Vasilii Nikolaeich Maksimov who drowned with his son while crossing the Zhuia River in 2012. The field research and laboratory analysis for this article was sponsored mainly by a grant from the Research Council of Norway (NFR 179316) within the multinational research framework “BOREAS: Histories from the North” organized by the European Science Foundation EUROCORES programme. A portion of the laboratory work, and the time for writing an analysis was made possible by an Advanced Grant from the European Research Council (ERC AdG 295458). The research could not have been carried out without the in-kind support, equipment and expertise of the Irkutsk State Technological University and the logistical support of the mining enterprise ‘Svetlyi’ based in Bodaibo. We are grateful to Iurii Vasil’evich Zharkov of the goldmining company Vitim and his uncle Iurii Alekseevich Zharkov of Svetlyi Ltd for professionally and reliably arranging ground transport for us and our equipment to and from the banks of the Zhuia River. We are also grateful to Iurii Konstantinovich Polititsyn, a lifetime resident of Svetlyi, who gave advice on sites of previous Evenki occupation and whose family helped us to navigate the river and organise the fieldwork. For this article, DGA was the principal investigator of the two grants, participated in most of the fieldwork, and composed this English text consulting Russian-language drafts prepared by EMI and OPV. EMI organized the fieldwork, conducted the trench digging, and prepared preliminary versions of the maps. OPV participated in the fieldwork, collected botanical samples, and participated in the interpretation of the pollen diagrams. ML participated in the fieldwork and conducted the phosphate analysis. The arduous work of identifying and counting the pollen grains, fungal spores and charcoal fragments was done by NVK in her laboratory in Irkutsk. We are indebted to our colleagues Drs. Ed Schofield and Dmitryi Mauquoy of the School of Geosciences at the University of Aberdeen for drafting the pollen diagrams and constructing the age-depth model and to Paul Ledger and Ilse Kamerling, also of the University of Aberdeen, for helping draft the final versions of the maps and figures.Peer reviewedPostprin

    Cancellation of soft and collinear divergences in noncommutative QED

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    In this paper, we investigate the behavior of non-commutative IR divergences and will also discuss their cancellation in the physical cross sections. The commutative IR (soft) divergences existing in the non-planar diagrams will be examined in order to prove an all order cancellation of these divergences using the Weinberg's method. In non-commutative QED, collinear divergences due to triple photon splitting vertex, were encountered, which are shown to be canceled out by the non-commutative version of KLN theorem. This guarantees that there is no mixing between the Collinear, soft and non-commutative IR divergences

    Mixing and condensation in a wet granular medium

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    We have studied the effect of small amounts of added liquid on the dynamic behavior of a granular system consisting of a mixture of glass beads of two different sizes. Segregation of the large beads to the top of the sample is found to depend in a nontrivial way on the liquid content. A transition to viscoplastic behavior occurs at a critical liquid content, which depends upon the bead size. We show that this transition can be interpreted as a condensation due to the hysteretic liquid bridge forces connecting the beads, and provide the corresponding phase diagram.Comment: submitted to PR

    Verification of band offsets and electron effective masses in GaAsN/GaAs quantum wells : Spectroscopic experiment versus 10-band k.p modeling

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    Optical transitions in GaAs1-xNx/GaAs quantum wells (QWs) have been probed by two complementary techniques, modulation spectroscopy in a form of photoreflectance and surface photovoltage spectroscopy. Transition energies in QWs of various widths and N contents have been compared with the results of band structure calculations based on the 10-band k.p Hamiltonian. Due to the observation of higher order transitions in the measured spectra, the band gap discontinuities at the GaAsN/GaAs interface and the electron effective masses could be determined, both treated as semi-free parameters to get the best matching between the theoretical and experimental energies. We have obtained the chemical conduction band offset values of 86% for x = 1.2% and 83% for x = 2.2%, respectively. For these determined band offsets, the electron effective masses equal to about 0.09 m(o) in QWs with 1.2% N and 0.15 m(o) for the case of larger N content of 2.2%.Publisher PDFPeer reviewe

    Quantum key distribution with realistic states: photon-number statistics in the photon-number splitting attack

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    Quantum key distribution can be performed with practical signal sources such as weak coherent pulses. One example of such a scheme is the Bennett-Brassard protocol that can be implemented via polarization of the signals, or equivalent signals. It turns out that the most powerful tool at the disposition of an eavesdropper is the photon-number splitting attack. We show that this attack can be extended in the relevant parameter regime such as to preserve the Poissonian photon number distribution of the combination of the signal source and the lossy channel.Comment: 4 page

    State care in childhood and adult mortality: a systematic review and meta-analysis of prospective cohort studies

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    BACKGROUND: Removal from family of origin to state care can be a highly challenging childhood experience and is itself linked to an array of unfavourable outcomes in adult life. We aim to synthetise evidence on the risk of adult mortality in people with a history of state care in early life, and assess the association according to different contexts. METHODS: In this systematic review and meta-analysis, we focused on four health outcomes hypothesised to be associated with exposure to early state care: total mortality, cardiovascular disease, cancer, and suicide. We searched the electronic databases PubMed and Embase from inception to Jan 21, 2022, for studies fulfilling the following criteria: it was a prospective study in which the assessment of care was made up to 18 years of age; it included an unexposed comparator group; the focus of the study was temporary out-of-home care and not adoption; mortality surveillance was extended into adulthood; standard estimates of association (eg, relative risk, odds ratios, or hazard ratios) and variance (eg, CIs and SE) were provided; the study appeared in a peer-reviewed journal; and the study was published in English. An adapted Cochrane Risk of Bias Tool was used to assess study quality. We extracted estimates of association and variance from qualifying studies and augmented these findings with analyses of unpublished data from individual participants in two UK birth cohorts-ie, the 1958 and 1970 studies (total n=21 936). We computed hazard ratios with accompanying 95% CIs for care and each health outcome separately for each study, and then pooled the results using a random-effects meta-analysis. This review is registered at PROSPERO, CRD42021254665. FINDINGS: We identified 210 potentially eligible published articles, of which 14 met our inclusion criteria (two studies were unpublished). Of 3 223 580 individuals drawn from 13 studies, those who were exposed to care in childhood had twice the risk of total mortality in adulthood relative to those without a history of care in childhood (summary risk ratio 2·21 [95% CI 1·62-3·02]), with study-specific estimates varying between 1·04 and 5·77 (I2 =98%). Despite some attenuation, this association remained following adjustment for other measures of early-life adversity; extended into middle and older age; was stronger in higher-quality studies; and was of equal magnitude according to sex, geographical region, and birth year. There was some suggestion of sensitive periods of exposure to care, whereby individuals who entered state care for the first time in adolescence (2·47 [0·98-6·52]) had greater rates of mortality than those doing so early in the life course (1·75 [1·25-2·45]). In four studies including 534 890 people, children in care had more than three times the risk of completed suicide in adulthood relative to their unexposed peers (3·35 [2·41-4·68]), with study-specific estimates ranging between 2·42 and 5·85 (I2=72%). The magnitude of this association was weaker after adjustment for multiple covariates; in men than in women; and in lower-quality studies. INTERPRETATION: Our results for adult mortality suggest child protection systems, social policy, and health services following care graduation are insufficient to mitigate the adverse experiences that might have preceded placement into care and those that might accompany it. FUNDING: None
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