310 research outputs found

    Creating a Differentiated Mathematics Classroom

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    Recognizing different mathematical learning styles and adapting differentiated teaching strategies can facilitate student learning

    Panel: Teaching with Enterprise Systems

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    Enterprise Systems (ES) and other large software packages have become a critical component in most large and many medium and small-sized companies. These companies need employees with ES experience to help them install, extend, and achieve benefits from these systems. The challenges universities face in implementing an ES into a curriculum and in achieving educational benefits from such implementations differ from those of business organizations, but are no less difficult. This panel is designed to contribute to the ability of many more universities to provide a stimulating ES-based educational environment for students. It will address issues such as: ES educational objectives and audiences, ES-based skills for students, the ES software suites being used, ES textbooks, lab exercises and cases, technical infrastructure support issues, acquiring support and maintaining commitment from the school and its faculty, faculty resistance and how to overcome it, training the faculty, and achieving your ES educational objectives. This panel is composed of educators with many years of experience in providing an ES educational environment. They will present the lessons they learned from their experiences and will answer questions posed by the audience. For further information on their ES educational activities, see (Antonucci, Corbitt, Stewart and Harris, 2004; Corbitt and Mensching, 2000; Fedorowicz, Gelinas, Usoff and Hachey, 2004; Stewart, Tracy, Boykin, Najm, Rosemann, Carpinetti and Watson, 2002; Strong, Johnson and Mistry, 2004; Watson and Schneider, 1999)

    Synchronous Chip-to-Chip Communication with a Multi-Chip Resonator Clock Distribution Network

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    Superconducting digital circuits are a promising approach to build packaged-level integrated systems with high energy-efficiency and computational density. In such systems, performance of the data link between chips mounted on a multi-chip module (MCM) is a critical driver of performance. In this work we report a synchronous data link using Reciprocal Quantum Logic (RQL) enabled by resonant clock distribution on the chip and on the MCM carrier. The simple physical link has only four Josephson junctions and 3 fJ/bit dissipation, including a 300 W/W cooling overhead. The driver produces a signal with 35\,GHz analog bandwidth and connects to a single-ended receiver via 20 Ω\Omega Nb Passive Transmission Line (PTL). To validate this link, we have designed, fabricated and tested two 32×\times32 mm2^2 MCMs with eight 5×\times5 mm2^2 chips connected serially and powered with a meander clock, and with four 10×\times10 mm2^2 chips powered with a 2 GHz resonant clock. The meander clock MCM validates performance of the data link components, and achieved 5.4 dB AC bias margin with no degradation relative to individual chip test. The resonator MCM validates synchronization between chips, with a measured AC bias margin up to 4.8 dB between two chips. The resonator MCM is capable of powering circuits of 4 million Josephson junctions across the four chips with a projected 10 Gbps serial data rate.Comment: 8 pages, 8 figure

    Cosmic ray electrons and positrons from discrete stochastic sources

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    The distances that galactic cosmic ray electrons and positrons can travel are severely limited by energy losses to at most a few kiloparsec, thereby rendering the local spectrum very sensitive to the exact distribution of sources in our galactic neighbourhood. However, due to our ignorance of the exact source distribution, we can only predict the spectrum stochastically. We argue that even in the case of a large number of sources the central limit theorem is not applicable, but that the standard deviation for the flux from a random source is divergent due to a long power law tail of the probability density. Instead, we compute the expectation value and characterise the scatter around it by quantiles of the probability density using a generalised central limit theorem in a fully analytical way. The uncertainty band is asymmetric about the expectation value and can become quite large for TeV energies. In particular, the predicted local spectrum is marginally consistent with the measurements by Fermi-LAT and HESS even without imposing spectral breaks or cut-offs at source. We conclude that this uncertainty has to be properly accounted for when predicting electron fluxes above a few hundred GeV from astrophysical sources.Comment: 16 pages, 8 figures; references and clarifying comment added; to appear in JCA

    Evaluation and Treatment in Urology for Nocturia Caused by Nonurological Mechanisms:Guidance from the PLANET Study

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    Patients with nocturia are commonly referred to urology clinics, including many for whom a nonurological medical condition is responsible for their symptoms. The PLanning Appropriate Nocturia Evaluation and Treatment (PLANET) study was established to develop practical approaches to equip healthcare practitioners to deal with the diverse causes of nocturia, based on systematic reviews and expert consensus. Initial assessment and therapy need to consider the possibility of one or more medical conditions falling into the “SCREeN” areas of Sleep medicine (insomnia, periodic limb movements of sleep, parasomnias, and obstructive sleep apnoea), Cardiovascular (hypertension and congestive heart failure), Renal (chronic kidney disease), Endocrine (diabetes mellitus, thyroid disease, pregnancy/menopause, and diabetes insipidus), and Neurology. Medical and medication causes of xerostomia should also be considered. Some key indicators for these conditions can be identified in urology clinics, working in partnership with the primary care provider. Therapy of the medical condition in some circumstances lessens the severity of nocturia. However, in many cases there is a conflict between the two, in which case the medical condition generally takes priority on safety grounds. It is important to provide patients with a realistic expectation of therapy and awareness of limitations of current therapeutic options for nocturia.Patient summaryNocturia is the symptom of waking at night to pass urine. Commonly, this problem is referred to urology clinics. However, in some cases, the patient does not have a urological condition but actually a condition from a different speciality of medicine. This article describes how best the urologist and the primary care doctor can work together to assess the situation and make sensible and safe treatment suggestions. Unfortunately, there is sometimes no safe or effective treatment choice for nocturia, and treatment needs to focus instead on supportive management of symptoms

    Radioactive 26Al and massive stars in the Galaxy

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    Gamma-rays from radioactive 26Al (half life ~7.2 10^5 yr) provide a 'snapshot' view of ongoing nucleosynthesis in the Galaxy. The Galaxy is relatively transparent to such gamma-rays, and emission has been found concentrated along the plane of the Galaxy. This led to the conclusion1 that massive stars throughout the Galaxy dominate the production of 26Al. On the other hand, meteoritic data show locally-produced 26Al, perhaps from spallation reactions in the protosolar disk. Furthermore, prominent gamma-ray emission from the Cygnus region suggests that a substantial fraction of Galactic 26Al could originate in localized star-forming regions. Here we report high spectral resolution measurements of 26Al emission at 1808.65 keV, which demonstrate that the 26Al source regions corotate with the Galaxy, supporting its Galaxy-wide origin. We determine a present-day equilibrium mass of 2.8 (+/-0.8) M_sol of 26Al. We use this to estimate that the frequency of core collapse (i.e. type Ib/c and type II) supernovae to be 1.9(+/- 1.1) events per century.Comment: accepted for publication in Nature, 24 pages including Online Supplements, 11 figures, 1 tabl

    Complementarity of Galactic radio and collider data in constraining WIMP dark matter models

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    In this work we confront dark matter models to constraints that may be derived from radio synchrotron radiation from the Galaxy, taking into account the astrophysical uncertainties and we compare these to bounds set by accelerator and complementary indirect dark matter searches. Specifically we apply our analysis to three popular particle physics models. First, a generic effective operator approach, in which case we set bounds on the corresponding mass scale, and then, two specific UV completions, the Z' and Higgs portals. We show that for many candidates, the radio synchrotron limits are competitive with the other searches, and could even give the strongest constraints (as of today) with some reasonable assumptions regarding the astrophysical uncertainties.Comment: 22 pages, 12 figure

    Ultra-High Energy Neutrino Fluxes: New Constraints and Implications

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    We apply new upper limits on neutrino fluxes and the diffuse extragalactic component of the GeV gamma-ray flux to various scenarios for ultra high energy cosmic rays and neutrinos. As a result we find that extra-galactic top-down sources can not contribute significantly to the observed flux of highest energy cosmic rays. The Z-burst mechanism where ultra-high energy neutrinos produce cosmic rays via interactions with relic neutrinos is practically ruled out if cosmological limits on neutrino mass and clustering apply.Comment: 10 revtex pages, 9 postscript figure

    Effects of MDM2, MDM4 and TP53 Codon 72 Polymorphisms on Cancer Risk in a Cohort Study of Carriers of TP53 Germline Mutations

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    Previous studies have shown that MDM2 SNP309 and p53 codon 72 have modifier effects on germline P53 mutations, but those studies relied on case-only studies with small sample sizes. The impact of MDM4 polymorphism on tumor onset in germline mutation carriers has not previously been studied.We analyzed 213 p53 germline mutation carriers including 168(78.9%) affected with cancer and 174 who had genotypic data. We analyzed time to first cancer using Kaplan-Meier and Cox proportional hazards methods, comparing risks according to polymorphism genotypes. For MDM2 SNP309, a significant difference of 9.0 years in the average age of cancer diagnosis was observed between GG/GT and TT carriers (18.6 versus 27.6 years, P = 0.0087). The hazards ratio was 1.58 (P = 0.03) comparing risks among individuals with GG/GT to risk among TT, but this effect was only significant in females (HR = 1.60, P = 0.02). Compared to other genotypes, P53 codon 72 PP homozygotes had a 2.24 times (P = 0.03) higher rate for time to develop cancer. We observed a multiplicative joint effect of MDM2 and p53 codon72 polymorphism on risk. The MDM4 polymorphism had no significant effects.Our results suggest that the MDM2 SNP309 G allele is associated with cancer risk in p53 germline mutation carriers and accelerates time to cancer onset with a pronounced effect in females. A multiplicative joint effect exists between the MDM2 SNP309 G allele and the p53 codon 72 G allele in the risk of cancer development. Our results further define cancer risk in carriers of germline p53 mutations
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