5,098 research outputs found

    A Review and Analysis of Literature for the Use of Humor in Corporate Instructional Video Programs : Guidelines for Practice and Research

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    This study was designed to gather and analyze the existing research on the use of humor in instructional materials in order to generalize those findings to corporate instructional video programs. Due to the lack of empirical research done in corporate settings, the research involving humor and children, and humor and college students, was analyzed. [This is an excerpt from the abstract. For the complete abstract, please see the document.

    Introducing The Radiation-Hardened Voltage Regulators Rhfl4913 and the Rhfl6000

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    With the progressive scaling of the modern CMOS processes arising during the recent years, for the devices operating in space the susceptivity to the over-voltage events has increased. They have become more stringent the requirements in terms of accuracy of the supply voltage worth their reliability. For the case of CMOS memories operating at 1.5V it is essential to guarantee a variation of the nominal VOUT to within 5% including those arising on the supply voltage during the transients. Finally, for a voltage regulator operating in space one of the most salient effects are the voltage transients induced on the output by the single events (SET) that may exceed the aforementioned 5% threshold. This can be cause of damage into the circuitry fed downstream. Among the devices in ST portfolio designed to cope with the mentioned effects there are two voltage regulators, the RHFL4913 and the RHFL6000. The first one was initially developed for the harsh environment of the Large Hadron Collider. It was tested by the CERN and it was proven that it is able to operate without problems at up to 100Mrad TID at High Dose Rate without problems 1. Subsequent tests performed at low dose rates (expected in space environment), showed that this device is also ELDRS free up to 1Mrad 2. Further tests performed by NASA highlighted also a certain susceptivity to the SET (3) but this issue can be circumvented by the adoption of a properly sized up RC low pass filter put between the regulator output and the load as shown in fig.1 (4). With the above provision, this regulator is suitable for operating in space. Currently, the RHFL4913 is QMLV qualified

    The WISSH quasars Project: II. Giant star nurseries in hyper-luminous quasars

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    Studying the coupling between the energy output produced by the central quasar and the host galaxy is fundamental to fully understand galaxy evolution. Quasar feedback is indeed supposed to dramatically affect the galaxy properties by depositing large amounts of energy and momentum into the ISM. In order to gain further insights on this process, we study the SEDs of sources at the brightest end of the quasar luminosity function, for which the feedback mechanism is supposed to be at its maximum. We model the rest-frame UV-to-FIR SEDs of 16 WISE-SDSS Selected Hyper-luminous (WISSH) quasars at 1.8 < z < 4.6 disentangling the different emission components and deriving physical parameters of both the nuclear component and the host galaxy. We also use a radiative transfer code to account for the contribution of the quasar-related emission to the FIR fluxes. Most SEDs are well described by a standard combination of accretion disk+torus and cold dust emission. However, about 30% of them require an additional emission component in the NIR, with temperatures peaking at 750K, which indicates the presence of a hotter dust component in these powerful quasars. We measure extreme values of both AGN bolometric luminosity (LBOL > 10^47 erg/s) and SFR (up to 2000 Msun/yr). A new relation between quasar and star-formation luminosity is derived (LSF propto LQSO^(0.73)) by combining several Herschel-detected quasar samples from z=0 to 4. Future observations will be crucial to measure the molecular gas content in these systems, probe the impact between quasar-driven outflows and on-going star-formation, and reveal the presence of merger signatures in their host galaxies.Comment: 19 pages, 12 figures; Accepted for publication in Astronomy & Astrophysics on June 13, 201

    An Overview on Cryptococcal Meningitis

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    Star-forming dwarf galaxies in the Virgo cluster: the link between molecular gas, atomic gas, and dust

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    We present 12^{12}CO(1-0) and 12^{12}CO(2-1) observations of a sample of 20 star-forming dwarfs selected from the Herschel Virgo Cluster Survey, with oxygen abundances ranging from 12 + log(O/H) ~ 8.1 to 8.8. CO emission is observed in ten galaxies and marginally detected in another one. CO fluxes correlate with the FIR 250 μ\mum emission, and the dwarfs follow the same linear relation that holds for more massive spiral galaxies extended to a wider dynamical range. We compare different methods to estimate H2 molecular masses, namely a metallicity-dependent CO-to-H2 conversion factor and one dependent on H-band luminosity. The molecular-to-stellar mass ratio remains nearly constant at stellar masses <~ 109^9 M⊙_{\odot}, contrary to the atomic hydrogen fraction, MHI_{HI}/M∗_*, which increases inversely with M∗_*. The flattening of the MH2_{H_2}/M∗_* ratio at low stellar masses does not seem to be related to the effects of the cluster environment because it occurs for both HI-deficient and HI-normal dwarfs. The molecular-to-atomic ratio is more tightly correlated with stellar surface density than metallicity, confirming that the interstellar gas pressure plays a key role in determining the balance between the two gaseous components of the interstellar medium. Virgo dwarfs follow the same linear trend between molecular gas mass and star formation rate as more massive spirals, but gas depletion timescales, τdep\tau_{dep}, are not constant and range between 100 Myr and 6 Gyr. The interaction with the Virgo cluster environment is removing the atomic gas and dust components of the dwarfs, but the molecular gas appears to be less affected at the current stage of evolution within the cluster. However, the correlation between HI deficiency and the molecular gas depletion time suggests that the lack of gas replenishment from the outer regions of the disc is lowering the star formation activity.Comment: 19 pages, 11 figures, accepted for publication in Astronomy & Astrophysic

    Bamboo Cellulose nanocrystals inserted in the composition of cementitious mortars

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    This research deals with obtaining nanocrystals of cellulose from eucalyptus, which aims to insert and increase the strength of mortar, using nanotechnology for its improvement as an alternative way to reinforce the composition of the material. The methodology used to obtain this is a chemical treatment that must be carried out in two stages. The first is an alkaline treatment using sodium hydroxide (NaOH) and the second part, which is where the result is obtained, is acid hydrolysis using sulfuric acid (H2SO4). Briefly, cellulose, a polymer that is very abundant on the earth, when chemically treated becomes a material that can satisfactorily improve the strength of mortar or any other cementitious material. Its use in the future as a form of improvement, will become of paramount importance in civil construction, because it helps in the improvement of one of the most used materials in the industry in order to think about sustainability.info:eu-repo/semantics/publishedVersio

    Comparisons of submental and groin vascularized lymph node flaps transfer for breast cancer-related lymphedema

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    Background: The vascularized groin and submental lymph node (VGLN and VSLN) flaps are valuable options in the treatment of lymphedema. This study was to compare outcomes between VGLN and VSLN transfers for breast cancer-related lymphedema. Methods: Between January 2008 and December 2016, VGLN and VSLN transfers for upper limb lymphedema were compared including flap characteristics, flap elevation time, complications, and limb circumference changes. Results: All flaps survived. Similar vein (2.6 versus 3.2 mm; P = 0.3) and artery diameter (2.1 versus 2.8 mm; P = 0.3) and number of lymph nodes (3 versus 4; P = 0.4) were found between VGLN and VSLN groups, respectively. Circumferential reduction rate was higher in VSLN than VGLN (P = 0.04) group. Vascular complication rate with salvage rate was not statistically different between the 2 groups. Donor-site complication and total complication rates were statistically higher in VGLN than VSLN flaps (7.7% versus 0%, P = 0.004; 46.2% versus 23.3%, P = 0.002). At a mean 39.8 ± 22.4 months, the circumferential reduction rate was statistically higher in VSLN than in the VGLN group (55.5 ± 14.3% versus 48.4 ± 23.9%, P = 0.04). Both flaps were effectively decreased in the episodes of cellulitis. Conclusions: Both VGLN and VSLN flaps are valuable surgical options in treating breast cancer-related lymphedema. However, the VSLN flap for breast cancer-related lymphedema is better in providing more significant improvements in limb circumference, a faster flap harvest time, decreased complication rates, and minimal donor-site iatrogenic lymphedema

    The Overwhelming Postsplenectomy Sepsis: Role of Plastic Surgeon

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    The overwhelming post-splenectomy infection (OPSI) is a feared late complication of splenectomy, with high morbidity and a mortality rate of up to 50%. Although the management of this syndrome is the duty of clinical physicians, the interest of plastic surgeons in OPSI is related to the injury that can occur in tissues with an end circulation, such as the limb extremities, nasal tip, and lips. In the management of OPSI, surgical techniques are not highlighted. The role of the plastic surgeon can be fundamental for the prevention of further extension of the necrotic tissue, improving as much as possible the vascularization around it. Moreover, a critical role in the management of OPSI is avoiding superinfection of the necrotic areas by combining different techniques and methods, such as surgical debridements, negative pressure wound therapy, and conservative treatment. Last but not least, functional and aesthetic restoration of the injured parts is of paramount importance for the final outcome. In this article, we describe the management of two unvaccinated patients with necrosis of the extremities after OPSI

    The Herschel Virgo Cluster Survey XVI: a cluster inventory

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    Herschel FIR observations are used to construct Virgo cluster galaxy luminosity functions and to show that the cluster lacks the very bright and the numerous faint sources detected in field galaxy surveys. The far-infrared SEDs are fitted to obtain dust masses and temperatures and the dust mass function. The cluster is over dense in dust by about a factor of 100 compared to the field. The same emissivity (beta) temperature relation applies for different galaxies as that found for different regions of M31. We use optical and HI data to show that Virgo is over dense in stars and atomic gas by about a factor of 100 and 20 respectively. Metallicity values are used to measure the mass of metals in the gas phase. The mean metallicity is about 0.7 solar and 50% of the metals are in the dust. For the cluster as a whole the mass density of stars in galaxies is 8 times that of the gas and the gas mass density is 130 times that of the metals. We use our data to consider the chemical evolution of the individual galaxies, inferring that the measured variations in effective yield are due to galaxies having different ages, being affected to varying degrees by gas loss. Four galaxy scaling relations are considered: mass-metallicity, mass-velocity, mass-star formation rate and mass-radius - we suggest that initial galaxy mass is the prime driver of a galaxy's ultimate destiny. Finally, we use X-ray observations and galaxy dynamics to assess the dark and baryonic matter content compared to the cosmological model
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