The X-ray and gamma -ray spectrum of rotation-powered millisecond pulsars is investigated in a model for acceleration and pair cascades on open field lines above the polar caps. Although these ...pulsars have low surface magnetic fields, their short periods allow them to have large magnetospheric potential drops, but the majority do not produce sufficient pairs to completely screen the accelerating electric field. In these sources, the primary and secondary electrons continue to accelerate to high altitude, and their Lorentz factors are limited by curvature and synchrotron radiation reaction. The accelerating particles maintain high Lorentz factors and undergo cyclotron resonant absorption of radio emission that produces and maintains a large pitch angle, resulting in a strong synchrotron component. The resulting spectra consist of several distinct components: curvature radiation from primary electrons dominating from 1 to 100 GeV, synchrotron radiation from primary and secondary electrons dominating up to about 100 MeV, and much weaker inverse Compton radiation from primary electrons at 0.1-1 TeV. We find that the relative size of these components depends on pulsar period, period derivative, and neutron star mass and radius, with the level of the synchrotron component also depending sensitively on the radio emission properties. This model is successful in describing the observed X-ray and gamma -ray spectrum of PSR J0218+4232 as synchrotron radiation, peaking around 100 MeV and extending up to a turnover around several GeV. The predicted curvature radiation components from a number of millisecond pulsars, as well as the collective emission from the millisecond pulsars in globular clusters, should be detectable with AGILE and GLAST. We also discuss a hidden population of X-ray-quiet and radio-quiet millisecond pulsars that have evolved below the pair death line, some of which may be detectable by telescopes sensitive above 1 GeV.
The reporting of the first draft of the human genome in 2000 brought with it much hope for the future in what was felt as a paradigm shift toward improved health outcomes. Indeed, we have now mapped ...the majority of variation across human populations with landmark projects such as 1000 Genomes; in cancer, we have catalogued mutations across the primary carcinomas; whilst, for other diseases, we have identified the genetic variants with strongest association. Despite this, we are still awaiting the genetic revolution in healthcare to materialise and translate itself into the health benefits for which we had hoped. A major problem we face relates to our underestimation of the complexity of the genome, and that of biological mechanisms, generally. Fixation on DNA sequence alone and a 'rigid' mode of thinking about the genome has meant that the folding and structure of the DNA molecule -and how these relate to regulation- have been underappreciated. Projects like ENCODE have additionally taught us that regulation at the level of RNA is just as important as that at the spatiotemporal level of chromatin.In this review, we chart the course of the major advances in the biomedical sciences in the era pre- and post the release of the first draft sequence of the human genome, taking a focus on technology and how its development has influenced these. We additionally focus on gene editing via CRISPR/Cas9 as a key technique, in particular its use in the context of complex biological mechanisms. Our aim is to shift the mode of thinking about the genome to that which encompasses a greater appreciation of the folding of the DNA molecule, DNA- RNA/protein interactions, and how these regulate expression and elaborate disease mechanisms.Through the composition of our work, we recognise that technological improvement is conducive to a greater understanding of biological processes and life within the cell. We believe we now have the technology at our disposal that permits a better understanding of disease mechanisms, achievable through integrative data analyses. Finally, only with greater understanding of disease mechanisms can techniques such as gene editing be faithfully conducted.
Aim
Depression is common in Type 2 diabetes, yet rates vary. Overlap between symptoms of depression and diabetes may account for this variability in depression prevalence rates. We examined to what ...extent depression prevalence was a function of the proportion of depression–diabetes symptom overlap (items within symptom dimensions) and sample characteristics.
Methods
Electronic and hand searching of published and unpublished works identified 147 eligible papers. Of 3656 screened, 147 studies (149 samples, N = 17–229 047, mean sample age 25.4–82.8 years, with 152 prevalence estimates), using 24 validated depression questionnaires were selected. Sample size, publication type, sample type, gender, age, BMI, HbA1c, depression questionnaire and prevalence rates were extracted.
Results
Prevalence rates ranged from 1.8% to 88% (mean = 28.30%) and were higher in younger samples, samples with higher mean HbA1c and clinic samples. Diabetes–depression symptom overlap did not affect prevalence. A higher proportion of anhedonia, cognition, cognitive, negative affect and sleep disturbance symptoms, and a lower proportion of somatic symptoms were consistently associated with higher depression prevalence.
Conclusions
The lack of an overall effect of diabetes–depression symptom overlap might suggest that assessment of depression in Type 2 diabetes is generally not confounded by co‐occuring symptoms. However, questionnaires with proportionally more or fewer items measuring other symptom categories were associated with higher estimates of depression prevalence. Depression measures that focus on the cardinal symptoms of depression (e.g. negative affect and cognition), limiting symptoms associated with increasing diabetes symptomatology (e.g. sleep disturbance, cognitive) may most accurately diagnose depression.
What's new?
Prevalence of depression ranged from 1.8% to 88% (mean = 28.30%) across 147 studies. Younger sample age, higher HbA1c and clinic samples were associated with higher depression prevalence. There was no effect of depression–diabetes overlap items on depression estimates.
Questionnaires with a higher proportion of anhedonia, cognition, cognitive, negative affect and sleep disturbance symptoms, and a lower proportion of somatic symptoms were consistently associated with higher depression prevalence.
Depression measures that focus on the cardinal symptoms of depression (e.g. negative affect and cognition), limiting symptoms associated with increased diabetes symptomatology (e.g. sleep disturbance, cognitive) may most accurately diagnose depression.
ABSTRACT We report the discovery of a large, sudden, and persistent increase in the spin-down rate of B0540-69, a young pulsar in the Large Magellanic Cloud, using observations from the Swift and ...RXTE satellites. The relative increase in the spin-down rate of 36% is unprecedented for B0540-69. No accompanying change in the spin rate is seen, and no change is seen in the pulsed X-ray emission from B0540-69 following the change in the spin-down rate. Such large relative changes in the spin-down rate are seen in the recently discovered class of "intermittent pulsars," and we compare the properties of B0540-69 to such pulsars. We consider possible changes in the magnetosphere of the pulsar that could cause such a large change in the spin-down rate.
We report the discovery of eight gamma-ray pulsars in blind frequency searches using the LAT, onboard the Fermi Gamma-ray Space Telescope. Five of the eight pulsars are young (tau_c<100 kyr), ...energetic (Edot>10^36 erg/s), and located within the Galactic plane (|b|<3 deg). The remaining three are older, less energetic, and located off the plane. Five pulsars are associated with sources included in the LAT bright gamma-ray source list, but only one, PSR J1413-6205, is clearly associated with an EGRET source. PSR J1023-5746 has the smallest characteristic age (tau_c=4.6 kyr) and is the most energetic (Edot=1.1E37 erg/s) of all gamma-ray pulsars discovered so far in blind searches. PSRs J1957+5033 and J2055+25 have the largest characteristic ages (tau_c~1 Myr) and are the least energetic (Edot~5E33 erg/s) of the newly-discovered pulsars. We present the timing models, light curves, and detailed spectral parameters of the new pulsars. We used recent XMM observations to identify the counterpart of PSR J2055+25 as XMMU J205549.4+253959. In addition, publicly available archival Chandra X-ray data allowed us to identify the likely counterpart of PSR J1023-5746 as a faint, highly absorbed source, CXOU J102302.8-574606. The large X-ray absorption indicates that this could be among the most distant gamma-ray pulsars detected so far. PSR J1023-5746 is positionally coincident with the TeV source HESS J1023-575, located near the young stellar cluster Westerlund 2, while PSR J1954+2836 is coincident with a 4.3 sigma excess reported by Milagro at a median energy of 35 TeV. Deep radio follow-up observations of the eight pulsars resulted in no detections of pulsations and upper limits comparable to the faintest known radio pulsars, indicating that these can be included among the growing population of radio-quiet pulsars in our Galaxy being uncovered by the LAT, and currently numbering more than 20.
With the large sample of young γ-ray pulsars discovered by the Fermi Large Area Telescope (LAT), population synthesis has become a powerful tool for comparing their collective properties with model ...predictions. We synthesised a pulsar population based on a radio emission model and four γ-ray gap models (Polar Cap, Slot Gap, Outer Gap, and One Pole Caustic). Applying γ-ray and radio visibility criteria, we normalise the simulation to the number of detected radio pulsars by a select group of ten radio surveys. The luminosity and the wide beams from the outer gaps can easily account for the number of Fermi detections in 2 years of observations. The wide slot-gap beam requires an increase by a factor of ~10 of the predicted luminosity to produce a reasonable number of γ-ray pulsars. Such large increases in the luminosity may be accommodated by implementing offset polar caps. The narrow polar-cap beams contribute at most only a handful of LAT pulsars. Using standard distributions in birth location and pulsar spin-down power (Ė), we skew the initial magnetic field and period distributions in a an attempt to account for the high ĖFermi pulsars. While we compromise the agreement between simulated and detected distributions of radio pulsars, the simulations fail to reproduce the LAT findings: all models under-predict the number of LAT pulsars with high Ė, and they cannot explain the high probability of detecting both the radio and γ-ray beams at high Ė. The beaming factor remains close to 1.0 over 4 decades in Ė evolution for the slot gap whereas it significantly decreases with increasing age for the outer gaps. The evolution of the enhanced slot-gap luminosity with Ė is compatible with the large dispersion of γ-ray luminosity seen in the LAT data. The stronger evolution predicted for the outer gap, which is linked to the polar cap heating by the return current, is apparently not supported by the LAT data. The LAT sample of γ-ray pulsars therefore provides a fresh perspective on the early evolution of the luminosity and beam width of the γ-ray emission from young pulsars, calling for thin and more luminous gaps.
The Vela supernova remnant (SNR) is the closest SNR to Earth containing an active pulsar, the Vela pulsar (PSR B0833-45). This pulsar is an archetype of the middle-aged pulsar class and powers a ...bright pulsar wind nebula (PWN), Vela-X, spanning a region of 2degrees x 3degrees south of the pulsar and observed in the radio, X-ray, and very high energy gamma -ray domains. The detection of the Vela-X PWN by the Fermi Large Area Telescope (LAT) was reported in the first year of the mission. Subsequently, we have reinvestigated this complex region and performed a detailed morphological and spectral analysis of this source using 4 yr of Fermi-LAT observations. This study lowers the threshold for morphological analysis of the nebula from 0.8 GeV to 0.3 GeV, allowing for the inspection of distinct energy bands by the LAT for the first time. We describe the recent results obtained on this PWN and discuss the origin of the newly detected spatial features.
Post-Project Reviews (PPRs) are a rich source of knowledge and data for organisations – if organisations have the time and resources to analyse them. Too often these reports are stored, unread by ...many who could benefit from them. PPR reports attempt to document the project experience – both good and bad. If these reports were analysed collectively, they may expose important detail, e.g. recurring problems or examples of good practice, perhaps repeated across a number of projects. However, because most companies do not have the resources to thoroughly examine PPR reports, either individually or collectively, important insights and opportunities to learn from previous projects, are missed. This research explores the application of knowledge discovery techniques and Text Mining to uncover patterns, associations, and trends from PPR reports. The results might then be used to address problem areas, enhance processes, and improve customer relationships. A case study related to two construction companies is presented in this paper and knowledge discovery techniques are used to analyse 50 PPR reports collected during the last three years. The case study has been examined in six contexts and the results show that Text Mining has a good potential to improve overall knowledge reuse and exploitation.
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