Relativistic effects in electromagnetic nuclear responses in the quasi-elastic delta region

A new non-relativistic expansion in terms of the nucleon's momentum inside nuclear matter of the current for isobar electro-excitation from the nucleon is performed. Being exact with respect to the transferred energy and momentum, this yields new current operators which retain important aspects of relativity not taken into account in the traditional non-relativistic reductions. The transition current thus obtained differs from the leading order of the traditional expansion by simple multiplicative factors. These depend on the momentum and energy transfer and can be easily included together with relativistic kinematics in non-relativistic, many-body models of isobar electro-excitation in nuclei. The merits of the new current are tested by comparing with the unexpanded electromagnetic nuclear responses in the isobar peak computed in a relativistic Fermi gas framework. The sensitivity of the relativistic responses to the isobar's magnetic, electric and Coulomb form factors and the finite width of the isobar is analyzed.Comment: 26 pages plus 6 figure

Observation of hard scattering in photoproduction events with a large rapidity gap at HERA

Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the $\gamma p$ centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil

D* Production in Deep Inelastic Scattering at HERA

This paper presents measurements of D^{*\pm} production in deep inelastic scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The data have been taken with the ZEUS detector at HERA. The decay channel $D^{*+}\to (D^0 \to K^- \pi^+) \pi^+$ (+ c.c.) has been used in the study. The $e^+p$ cross section for inclusive D^{*\pm} production with $5<Q^2<100 GeV^2$ and $y<0.7$ is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region {$1.3<p_T(D^{*\pm})<9.0$ GeV and $| \eta(D^{*\pm}) |<1.5$}. Differential cross sections as functions of p_T(D^{*\pm}), $\eta(D^{*\pm}), W$ and $Q^2$ are compared with next-to-leading order QCD calculations based on the photon-gluon fusion production mechanism. After an extrapolation of the cross section to the full kinematic region in p_T(D^{*\pm}) and $\eta$(D^{*\pm}), the charm contribution $F_2^{c\bar{c}}(x,Q^2)$ to the proton structure function is determined for Bjorken $x$ between 2 $\cdot$ 10$^{-4}$ and 5 $\cdot$ 10$^{-3}$.Comment: 17 pages including 4 figure

Observation of Scaling Violations in Scaled Momentum Distributions at HERA

Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of $x$ and $Q^2$ using the ZEUS detector. The evolution of the scaled momentum, $x_p$, with $Q^2,$ in the range 10 to 1280 $GeV^2$, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of $Q^2$.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde

Observation of Events with an Energetic Forward Neutron in Deep Inelastic Scattering at HERA

In deep inelastic neutral current scattering of positrons and protons at the center of mass energy of 300 GeV, we observe, with the ZEUS detector, events with a high energy neutron produced at very small scattering angles with respect to the proton direction. The events constitute a fixed fraction of the deep inelastic, neutral current event sample independent of Bjorken x and Q2 in the range 3 · 10-4 \u3c xBJ \u3c 6 · 10-3 and 10 \u3c Q2 \u3c 100 GeV2

Specificity of psychosis, mania and major depression in a contemporary family study.

There has been increasing attention to the subgroups of mood disorders and their boundaries with other mental disorders, particularly psychoses. The goals of the present paper were (1) to assess the familial aggregation and co-aggregation patterns of the full spectrum of mood disorders (that is, bipolar, schizoaffective (SAF), major depression) based on contemporary diagnostic criteria; and (2) to evaluate the familial specificity of the major subgroups of mood disorders, including psychotic, manic and major depressive episodes (MDEs). The sample included 293 patients with a lifetime diagnosis of SAF disorder, bipolar disorder and major depressive disorder (MDD), 110 orthopedic controls, and 1734 adult first-degree relatives. The diagnostic assignment was based on all available information, including direct diagnostic interviews, family history reports and medical records. Our findings revealed specificity of the familial aggregation of psychosis (odds ratio (OR)=2.9, confidence interval (CI): 1.1-7.7), mania (OR=6.4, CI: 2.2-18.7) and MDEs (OR=2.0, CI: 1.5-2.7) but not hypomania (OR=1.3, CI: 0.5-3.6). There was no evidence for cross-transmission of mania and MDEs (OR=.7, CI:.5-1.1), psychosis and mania (OR=1.0, CI:.4-2.7) or psychosis and MDEs (OR=1.0, CI:.7-1.4). The strong familial specificity of psychotic, manic and MDEs in this largest controlled contemporary family study challenges the growing assertion that the major types of mood disorders are manifestations of a common underlying diathesis

Early childhood feeding practices and dental caries among Australian preschoolers

Published: 11 February 2020BACKGROUND:Recent reviews have proposed a causal relationship between prolonged breastfeeding and early childhood caries (ECC), but the evidence to date is inconsistent, with few cohort studies and limited investigation of key confounders. OBJECTIVE:This study aimed to investigate the relationship between dietary practices and early childhood caries in a birth cohort of Australian preschoolers. METHODS:Participants underwent a standardized dental examination at 2-3 y of age to determine the prevalence of ECC (based on the presence of decayed, missing, or filled tooth surfaces). Breastfeeding practices were reported at 3, 6, 12, and 24 mo of age. Intakes of free sugars were assessed at 1 and 2 y of age. Multivariable regression models generated prevalence ratios (PR) for the association between ECC and breastfeeding duration, and between ECC and sleep feeding practices at 1 y, controlling for sociodemographic factors and free sugars intake. RESULTS:There was no independent association between breastfeeding beyond 1 y of age and ECC (PR 1.42, 95% CI: 0.85, 2.38), or between breastfeeding to sleep and ECC (PR 1.12, 95% CI: 0.67, 1.88), although the direction of effect was suggestive of an association. The only factors independently associated with ECC were high free sugars intakes (PR 1.97, 95% CI: 1.13, 3.44), and greater socioeconomic disadvantage (PR 2.15, 95% CI: 1.08, 4.28). Most participants who were breastfed at 1 y of age had ceased by 18 mo or 2 y. CONCLUSIONS:Breastfeeding practices were not associated with ECC. Given the wide-ranging benefits of breastfeeding, and the low prevalence of sustained breastfeeding in this study and Australia in general, recommendations to limit breastfeeding are unwarranted, and breastfeeding should be promoted in line with global and national recommendations. To reduce the prevalence of early childhood caries, improved efforts are needed to limit foods high in free sugars.Gemma Devenish, Aqif Mukhtar, Andrea Begley, A John Spencer, W Murray Thomson, Diep Ha, Loc Do, and Jane A Scot

A tetrameric structure is not essential for activity in dihydrodipicolinate synthase DHDPS from Mycobacterium tuberculosis.

Dihydrodipicolinate synthase DHDPS is a validated antibiotic target for which a new approach to inhibitor design has been proposed disrupting native tetramer formation by targeting the dimer dimer interface. In this study, rational design afforded a variant of Mycobacterium tuberculosis, Mtb DHDPS A204R, with disrupted quaternary structure. X ray crystallography at a resolution of 2.1 revealed a dimeric protein with an identical fold and active site structure to the tetrameric wild type enzyme. Analytical ultracentrifugation confirmed the dimeric structure in solution, yet the dimeric mutant has similar activity to the wild type enzyme. Although the affinity for both substrates was somewhat decreased, the high catalytic competency of the enzyme was surprising in the light of previous results showing that dimeric variants of the Escherichia coli and Bacillus anthracis DHDPS enzymes have dramatically reduced activity compared to their wild type tetrameric counterparts. These results suggest that Mtb DHDPS A204R is similar to the natively dimeric enzyme from S