5,072 research outputs found
Catastrogenesis: DM, GWs, and PBHs from ALP string-wall networks
No full textAxion-like particles (ALPs), a compelling candidate for dark matter (DM), are
the pseudo Nambu-Goldstone bosons of a spontaneously and explicitly broken
global symmetry. When the symmetry breaking happens after inflation, the
ALP cosmology predicts the formation of a string-wall network which must
annihilate early enough, producing gravitational waves (GWs) and primordial
black holes (PBHs), as well as non-relativistic ALPs. We call this process
catastrogenesis. We show that, under the generic assumption that the potential
has several degenerate minima, GWs from string-wall annihilation at
temperatures below 100 eV could be detected by future CMB and astrometry
probes, for ALPs with mass from to . In this case,
structure formation could limit ALPs to constitute a fraction of the DM and the
annihilation would produce mostly ``stupendously large" PBHs. For larger
annihilation temperatures, ALPs can constitute of DM, and the
annihilation could produce supermassive black holes with a mass of up to
as found at the center of large galaxies. Therefore our model
could solve two mysteries, the nature of the DM and the origin of these black
holes.Comment: 26 pages, 5 figures. Matches published versio
Springfield College Campus by William M. Simpson
No full textThis rendering by William M. Simpson of the picturesque campus of Springfield College in Springfield , Massachusetts , was commissioned by Mary - Beth A. Cooper , PhD , DM , the 13th President of Springfield College. The piece reflects some of the College's iconic and historic buildings . They are , from left , Alumni Hall , Marsh Memorial , and , at the far right , Judd Gymnasia . In the foreground is the Naismith Green . Nestled in the background , between Marsh Memorial and Judd Gymnasia , are International Hall , Schoo - Bemis Science Center , and Cheney Hall. Description is from card on back of drawing (see page 2).Description is from card on back of drawing (see page 2).; Item was framed, but was taken out of frame for preservation and space reasons.
A new small-bodied azhdarchoid pterosaur from the Lower Cretaceous of England and its implications for pterosaur anatomy, diversity and phylogeny
No full textBackgroundPterosaurs have been known from the Cretaceous sediments of the Isle of Wight (southern England, United Kingdom) since 1870. We describe the three-dimensional pelvic girdle and associated vertebrae of a small near-adult pterodactyloid from the Atherfield Clay Formation (lower Aptian, Lower Cretaceous). Despite acknowledged variation in the pterosaur pelvis, previous studies have not adequately sampled or incorporated pelvic characters into phylogenetic analyses.Methodology/principal findingsThe new specimen represents the new taxon Vectidraco daisymorrisae gen. et sp. nov., diagnosed by the presence of a concavity posterodorsal to the acetabulum and the form of its postacetabular process on the ilium. Several characters suggest that Vectidraco belongs to Azhdarchoidea. We constructed a pelvis-only phylogenetic analysis to test whether the pterosaur pelvis carries a useful phylogenetic signal. Resolution in recovered trees was poor, but they approximately matched trees recovered from analyses of total evidence. We also added Vectidraco and our pelvic characters to an existing total-evidence matrix for pterosaurs. Both analyses recovered Vectidraco within Azhdarchoidea.Conclusions/ significanceThe Lower Cretaceous strata of western Europe have yielded members of several pterosaur lineages, but Aptian pterosaurs from western Europe are rare. With a pelvis length of 40 mm, the new animal would have had a total length of c. 350 mm, and a wingspan of c. 750 mm. Barremian and Aptian pterodactyloids from western Europe show that small-bodied azhdarchoids lived alongside ornithocheirids and istiodactylids. This assemblage is similar in terms of which lineages are represented to the coeval beds of Liaoning, China; however, the number of species and specimens present at Liaoning is much higher. While the general phylogenetic composition of western European and Chinese communities appear to have been approximately similar, the differences may be due to different palaeoenvironmental and depositional settings. The western Europe pterodactyloid record may therefore be artificially low in diversity due to preservational factors
Efektivitas Penggunaan MATLAB dalam Penyelesaian Integral Numerik dengan Metode Simpson dan Romberg
No full textPenelitian ini bertujuan untuk mengevaluasi efektivitas penggunaan perangkat lunak Matlab dalam penyelesaian integral numerik menggunakan metode Simpson dan Romberg. Integral numerik menjadi alternatif penting dalam menghitung nilai integral yang tidak dapat diselesaikan secara analitik. Metode Simpson dan Romberg dipilih karena keunggulannya dalam menghasilkan pendekatan numerik yang akurat. Penelitian ini menggunakan pendekatan eksperimen dengan membandingkan hasil perhitungan manual dan hasil perhitungan menggunakan Matlab. Efektivitas dinilai berdasarkan tingkat akurasi hasil, efisiensi waktu pengerjaan, dan besarnya galat numerik. Temuan penelitian menunjukkan bahwa penggunaan Matlab secara signifikan mempercepat proses perhitungan dan meningkatkan ketepatan hasil dibandingkan metode manual. Selain itu, metode Romberg yang diimplementasikan melalui Matlab menghasilkan tingkat kesalahan yang lebih rendah dibandingkan metode Simpson, khususnya untuk fungsi-fungsi yang kompleks. Oleh karena itu, Matlab dapat dinyatakan efektif sebagai alat bantu dalam penyelesaian integral numerik, baik di bidang pendidikan maupun penelitian matematika terapa
Estimation of confidence limits for descriptive indexes derived from autoregressive analysis of time series: Methods and application to heart rate variability
No full textThe growing interest in personalized medicine requires making inferences from descriptive indexes estimated from individual recordings of physiological signals, with statistical analyses focused on individual differences between/within subjects, rather than comparing supposedly homogeneous cohorts. To this end, methods to compute confidence limits of individual estimates of descriptive indexes are needed. This study introduces numerical methods to compute such confidence limits and perform statistical comparisons between indexes derived from autoregressive (AR) modeling of individual time series. Analytical approaches are generally not viable, because the indexes are usually nonlinear functions of the AR parameters. We exploit Monte Carlo (MC) and Bootstrap (BS) methods to reproduce the sampling distribution of the AR parameters and indexes computed from them. Here, these methods are implemented for spectral and information-theoretic indexes of heart-rate variability (HRV) estimated from AR models of heart-period time series. First, the MS and BC methods are tested in a wide range of synthetic HRV time series, showing good agreement with a gold-standard approach (i.e. multiple realizations of the "true" process driving the simulation). Then, real HRV time series measured from volunteers performing cognitive tasks are considered, documenting (i) the strong variability of confidence limits' width across recordings, (ii) the diversity of individual responses to the same task, and (iii) frequent disagreement between the cohort-average response and that of many individuals. We conclude that MC and BS methods are robust in estimating confidence limits of these AR-based indexes and thus recommended for short-term HRV analysis. Moreover, the strong inter-individual differences in the response to tasks shown by AR-based indexes evidence the need of individual-by-individual assessments of HRV features. Given their generality, MC and BS methods are promising for applications in biomedical signal processing and beyond, providing a powerful new tool for assessing the confidence limits of indexes estimated from individual recordings
Postural sway changes during pregnancy
No full textObjectiveThis study aims to analyse changes in body sway over the course of pregnancy.Study designThis is a descriptive study in which stabilometric tests were applied at three stages of pregnancy and with a combination of different visual conditions (eyes open/closed) and support base configuration (feet together/apart). Twenty healthy pregnant women participated in the study. Changes in postural control with pregnancy were analysed via the elliptical area of the stabilograms and spectral analysis of the displacements of the centre of pressure (COP) along the lateral and anterior/posterior directions.ResultsThe elliptical area encompassing the COP significantly increased over the course of the pregnancy for the feet apart and eyes closed test protocols. The spectral analysis revealed a significant increase of COP oscillations along the anterior–posterior direction when subjects stood with the eyes open/feet together and feet apart. A reduction (significant) of the lateral oscillations of COP was observed for the eyes open/feet together protocol.ConclusionPregnancy induced significant changes in the postural control when pregnant women stood with a reduced support base or with eyes closed.<br/
Natalizumab-associated progressive multifocal leukoencephalopathy in patients with multiple sclerosis: lessons from 28 cases
No full textBackground Treatment of multiple sclerosis with natalizumab is complicated by rare occurrence of progressive multifocal leukoencephalopathy (PML). Between July, 2006, and November, 2009, there were 28 cases of confi rmed PML in patients with multiple sclerosis treated with natalizumab. Assessment of these clinical cases will help to inform future therapeutic judgments and improve the outcomes for patients.
Recent developments The risk of PML increases with duration of exposure to natalizumab over the fi rst 3 years of treatment. No new cases occurred during the fi rst two years of natalizumab marketing but, by the end of November, 2009, 28 cases had been confi rmed, of which eight were fatal. The median treatment duration to onset of symptoms was 25 months (range 6 80 months). The presenting symptoms most commonly included changes in cognition, personality, and motor performance, but several cases had seizures as the fi rst clinical event. Although PML has developed in patients without any previous use of disease-modifying therapies for multiple sclerosis, previous therapy
with immunosuppressants might increase risk. Clinical diagnosis by use of MRI and detection of JC virus in the CSF was established in all but one case. Management of PML has routinely used plasma exchange (PLEX) or immunoabsorption to hasten clearance of natalizumab and shorten the period in which natalizumab remains active (usually several months). Exacerbation of symptoms and enlargement of lesions on MRI have occurred within a few days to a few weeks after PLEX, indicative of immune reconstitution infl ammatory syndrome (IRIS). This syndrome seems to be more common and more severe in patients with natalizumab-associated PML than it is in patients with
HIV-associated PML.
Where next? Diagnosis of natalizumab-associated PML requires optimised clinical vigilance, reliable and sensitive PCR testing of the JC virus, and broadened criteria for recognition of PML lesions by use of MRI, including contrast enhancement. Optimising the management of IRIS reactions will be needed to improve outcomes. Predictive markers for patients at risk for PML must be sought. It is crucial to monitor the risk incurred during use of natalizumab beyond 3 years
Comparison of variation and diversity indices between healthy respiratory control (HC) and diabetic subjects (DM).
No full text(A) PCA plot for HC (red) and DM (green) (B) Rarefaction curve based on observed OTU by sampling group. (C) Chao1 box plots. (D) Shannon box plot. (E) Inverse Simpson box plot.</p
Spotlight on botulinum toxin and its potential in the treatment of stroke-related spasticity
No full textMichelle Kaku, David M Simpson Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA Abstract: Poststroke spasticity affects up to one-half of stroke patients and has debilitating effects, contributing to diminished activities of daily living, quality of life, pain, and functional impairments. Botulinum toxin (BoNT) is proven to be safe and effective in the treatment of focal poststroke spasticity. The aim of this review is to highlight BoNT and its potential in the treatment of upper and lower limb poststroke spasticity. We review evidence for the efficacy of BoNT type A and B formulations and address considerations of optimal injection technique, patient and caregiver satisfaction, and potential adverse effects of BoNT. Keywords: poststroke spasticity, botulinum toxin, onabotulinumtoxinA, incobotulinumtoxinA, rimabotulinumtoxinB 
On the singular sheaves in the fine Simpson moduli spaces of 1-dimensional sheaves
No full textpeer reviewedIn the Simpson moduli space of semi-stable sheaves with Hilbert polynomial on a projective plane we study the closed subvariety of sheaves that are not locally free on their support. We show that for it is a singular subvariety of codimension in . The blow up of along is interpreted as a (partial) modification of by line bundles (on support)
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