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"Young, D. R."
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الدين والتعليم والعلم في العصر العباسي
يضم هذا الكتاب الذي أصدرته جامعة كمبريدج تسع وعشرين دراسة قام بها عدد من أهم المتخصصين في تراث الحضارة العربية الإسلامية في مجالات الدراسات الدينية والتعليم والعلم وقد تنوعت موضوعات هذا التاب الفريد الممتع ما بين العلوم الإسلامية : كالتفسير وعلم الكلام والفقه، والعلوم العربية مثل اللغة والنحو وتصنيف المعاجم والقوامييس والشعر التعليمي وإسهامات المسلمين في الطب والفلك والكمياء والرياضيات والتنجيم. تناولت هذه الدراسات الأدب الصوفي والشعر التعليمي ورصدت موجزا لحركة الترجمة عن اللغة اليونانية في بداية عصور الثقافة العربية.
Book
Design and Operation of the ATLAS Transient Science Server
The Asteroid Terrestrial impact Last Alert System (ATLAS) system consists of two 0.5 m Schmidt telescopes with cameras covering 29 square degrees at plate scale of 1.86 arcsec per pixel. Working in tandem, the telescopes routinely survey the whole sky visible from Hawaii (above δ > − 50 ° ) every two nights, exposing four times per night, typically reaching o < 19 magnitude per exposure when the moon is illuminated and c < 19.5 magnitude per exposure in dark skies. Construction is underway of two further units to be sited in Chile and South Africa which will result in an all-sky daily cadence from 2021. Initially designed for detecting potentially hazardous near earth objects, the ATLAS data enable a range of astrophysical time domain science. To extract transients from the data stream requires a computing system to process the data, assimilate detections in time and space and associate them with known astrophysical sources. Here we describe the hardware and software infrastructure to produce a stream of clean, real, astrophysical transients in real time. This involves machine learning and boosted decision tree algorithms to identify extragalactic and Galactic transients. Typically we detect 10-15 supernova candidates per night which we immediately announce publicly. The ATLAS discoveries not only enable rapid follow-up of interesting sources but will provide complete statistical samples within the local volume of 100 Mpc. A simple comparison of the detected supernova rate within 100 Mpc, with no corrections for completeness, is already significantly higher (factor 1.5 to 2) than the current accepted rates.
Journal Article
Generalized boost transformations in finite volumes and application to Hamiltonian methods
A
bstract
The investigation of hadron interactions within lattice QCD has been facilitated by the well-known quantisation condition, linking scattering phase shifts to finite-volume energies. Additionally, the ability to utilise systems at finite total boosts has been pivotal in smoothly charting the energy-dependent behaviour of these phase shifts. The existing implementations of the quantization condition at finite boosts rely on momentum transformations between rest and moving frames, defined directly in terms of the energy eigenvalues. This energy dependence is unsuitable in the formulation of a Hamiltonian. In this work, we introduce a novel approach to generalise the three-momentum boost prescription, enabling the incorporation of energy-independent finite-volume Hamiltonians within moving frames. We demonstrate the application of our method through numerical comparisons, employing a phenomenological
ππ
scattering example.
Journal Article
Bulk-Solvent and Hydration-Shell Fluctuations, Similar to α- and β-Fluctuations in Glasses, Control Protein Motions and Functions
The concept that proteins exist in numerous different conformations or conformational substates, described by an energy landscape, is now accepted, but the dynamics is incompletely explored. We have previously shown that large-scale protein motions, such as the exit of a ligand from the protein interior, follow the dielectric fluctuations in the bulk solvent. Here, we demonstrate, by using mean-square displacements (msd) from Mössbauer and neutron-scattering experiments, that fluctuations in the hydration shell control fast fluctuations in the protein. We call the first type solvent-slaved or α-fluctuations and the second type hydration-shell-coupled or β-fluctuations. Solvent-slaved motions are similar to the α-fluctuations in glasses. Their temperature dependence can be approximated by a Vogel-Tammann-Fulcher relation and they are absent in a solid environment. Hydration-shell-coupled fluctuations are similar to the β-relaxation in glasses. They can be approximated by a Ferry or an Arrhenius relation, are much reduced or absent in dehydrated proteins, and occur in hydrated proteins even if embedded in a solid. They can be responsible for internal processes such as the migration of ligands within myoglobin. The existence of two functionally important fluctuations in proteins, one slaved to bulk motions and the other coupled to hydration-shell fluctuations, implies that the environment can control protein functions through different avenues and that no real protein transition occurs at ≈200 K. The large number of conformational substates is essential; proteins cannot function without this reservoir of entropy, which resides mainly in the hydration shell.
Journal Article
behavioral weight-loss intervention for persons with serious mental illness in psychiatric rehabilitation centers
Objective: Overweight and obesity are epidemic in populations with serious mental illnesses. We developed and pilot-tested a behavioral weight-loss intervention appropriately tailored for persons with serious mental disorders. Methods: We conducted a single-arm pilot study in two psychiatric rehabilitation day programs in Maryland, and enrolled 63 overweight or obese adults. The 6-month intervention provided group and individual weight management and group physical activity classes. The primary outcome was weight change from baseline to 6 months. Results: A total of 64% of those potentially eligible enrolled at the centers. The mean age was 43.7 years; 56% were women; 49% were white; and over half had schizophrenia or a schizoaffective disorder. One-third had hypertension and one-fifth had diabetes. In total, 52 (82%) completed the study; others were discharged from psychiatric centers before completion of the study. Average attendance across all weight management sessions was 70% (87% on days participants attended the center) and 59% for physical activity classes (74% on days participants attended the center). From a baseline mean of 210.9 lbs (s.d. 43.9), average weight loss for 52 participants was 4.5 lb (s.d. 12.8) (P<0.014). On average, participants lost 1.9% of body weight. Mean waist circumference change was 3.1 cm (s.d. 5.6). Participants on average increased the distance on the 6-minute walk test by 8%. Conclusion: This pilot study documents the feasibility and preliminary efficacy of a behavioral weight-loss intervention in adults with serious mental illness who were attendees at psychiatric rehabilitation centers. The results may have implications for developing weight-loss interventions in other institutional settings such as schools or nursing homes.
Journal Article
Gray matter textural heterogeneity as a potential in-vivo biomarker of fine structural abnormalities in Asperger syndrome
Brain imaging studies contribute to the neurobiological understanding of Autism Spectrum Conditions (ASC). Herein, we tested the prediction that distributed neurodevelopmental abnormalities in brain development impact on the homogeneity of brain tissue measured using texture analysis (TA; a morphological method for surface pattern characterization). TA was applied to structural magnetic resonance brain scans of 54 adult participants (24 with Asperger syndrome (AS) and 30 controls). Measures of mean gray-level intensity, entropy and uniformity were extracted from gray matter images at fine, medium and coarse textures. Comparisons between AS and controls identified higher entropy and lower uniformity across textures in the AS group. Data reduction of texture parameters revealed three orthogonal principal components. These were used as regressors-of-interest in a voxel-based morphometry analysis that explored the relationship between surface texture variations and regional gray matter volume. Across the AS but not control group, measures of entropy and uniformity were related to the volume of the caudate nuclei, whereas mean gray-level was related to the size of the cerebellar vermis. Similar to neuropathological studies, our study provides evidence for distributed abnormalities in the structural integrity of gray matter in adults with ASC, in particular within corticostriatal and corticocerebellar networks. Additionally, this
in-vivo
technique may be more sensitive to fine microstructural organization than other more traditional magnetic resonance approaches and serves as a future testable biomarker in AS and other neurodevelopmental disorders.
Journal Article
Process evaluation results from a school- and community-linked intervention: the Trial of Activity for Adolescent Girls (TAAG)
Process evaluation is a component of intervention research that evaluates whether interventions are delivered and received as intended. Here, we describe the process evaluation results for the Trial of Activity for Adolescent Girls (TAAG) intervention. The intervention consisted of four synergistic components designed to provide supportive school- and community-linked environments to prevent the decline in physical activity in adolescent girls. Process evaluation results indicate that the intervention components were delivered from intervention staff to teachers with high fidelity (84-97%) to the protocol and with lower fidelity (range: 18-93%) from teachers to students. Physical activity programs for girls, a unique feature of the TAAG intervention, increased from a mean of 10 programs per school to a mean of 16 and 15 in years 1 and 2, respectively, in intervention schools, with no change in control schools. These findings suggest that a multicomponent school- and community-based physical activity intervention can be delivered with fidelity and result in a middle school environment that supports physical activity for girls.
Journal Article
QED effects in the pseudoscalar meson sector
A
bstract
In this paper we present results on the pseudoscalar meson masses from a fully dynamical simulation of QCD+QED, concentrating particularly on violations of isospin symmetry. We calculate the
π
+
-
π
0
splitting and also look at other isospin violating mass differences. We have presented results for these isospin splittings in [1]. In this paper we give more details of the techniques employed, discussing in particular the question of how much of the symmetry violation is due to QCD, arising from the different masses of the
u
and
d
quarks, and how much is due to QED, arising from the different charges of the quarks. This decomposition is not unique, it depends on the renormalisation scheme and scale. We suggest a renormalisation scheme in which Dashen’s theorem for neutral mesons holds, so that the electromagnetic self-energies of the neutral mesons are zero, and discuss how the self-energies change when we transform to a scheme such as
M
S
¯
, in which Dashen’s theorem for neutral mesons is violated.
Journal Article
Directly calculating the glue component of the nucleon in lattice QCD: QCDSF–UKQCD–CSSM Collaborations
We are investigating the direct determination and non-perturbative renormalisation of gluon matrix elements. Such quantities are sensitive to ultra– violet fluctuations, and are in general statistically noisy. To obtain statistically significant results, we extend an earlier application of the Feynman–Hellmann theorem to gluonic matrix elements to calculate a renormalisation factor in the RI – MOM scheme, in the quenched case. This work demonstrates that the Feynman–Hellmann method is capable of providing a feasible option for calculating gluon quantities.
Journal Article
The delay of shock breakout due to circumstellar material evident in most type II supernovae
Type II supernovae (SNe II) originate from the explosion of hydrogen-rich supergiant massive stars. Their first electromagnetic signature is the shock breakout (SBO), a short-lived phenomenon that can last for hours to days depending on the density at shock emergence. We present 26 rising optical light curves of SN II candidates discovered shortly after explosion by the High Cadence Transient Survey and derive physical parameters based on hydrodynamical models using a Bayesian approach. We observe a steep rise of a few days in 24 out of 26 SN II candidates, indicating the systematic detection of SBOs in a dense circumstellar matter consistent with a mass loss rate of
M
̇
> 10
−4
M
⊙
yr
−1
or a dense atmosphere. This implies that the characteristic hour-timescale signature of stellar envelope SBOs may be rare in nature and could be delayed into longer-lived circumstellar material SBOs in most SNe II.
The shock breakout (SBO) is the first electromagnetic signature of a supernova (SN) explosion. Förster et al. find that in nearly all type II SNe they survey that the SBO occurs on a timescale of days, indicating that the progenitors were surrounded by thick circumstellar matter when they exploded.
Journal Article