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Being Limited (being + limited)
Selected AbstractsAzoospermia with Klippel-Feil anomalyINTERNATIONAL JOURNAL OF UROLOGY, Issue 2 2008Yukihiro Umemoto Abstract: We present a case of azoospermia with Klippel-Feil anomaly. Klippel-Feil anomaly is characterized by the fusion of two or more cervical vertebrae and a short neck, limitation of head movement, and low posterior hairline. The association of this anomaly with MURCS (Müllerian-duct asplasia, renal agenesis, and cervical somite dysplasia) is traditionally regarded as being limited to females, but it has been hypothesized that men displaying the combination of azoospermia, segmentation abnormalities of the cervicothoracic spine, and renal anomalies have a male analog of MURCS. Here we describe the first case of MURCS in a male in whom testicular sperm extraction was carried out. [source] The role that bond coat depletion of aluminum has on the lifetime of APS-TBC under oxidizing conditionsMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 7 2008D. Renusch Abstract Bond coat oxidation as well as bond coat depletion of Al are still believed to be a major degradation mechanism with respect to the lifetime of thermal barrier coating (TBC) systems. In this study the top coat lifetime is described as being limited by both bond coat depletion of Al and mechanical failure of the top coat. The empirical results are introduced by considering three spallation cases, namely, Al depletion failure, thermal fatigue failure, and thermal aging failure. Al depletion failure occurs when the Al content within the bond coat reaches a critical value. In this paper bond coat depletion of Al is modeled by considering the diffusion of Al into both the thermally grown oxide (TGO) and substrate. The diffusion model results are compared to Al concentration profiles measured with an electron beam microprobe. These measured results are from oxidized air plasma sprayed TBC systems (APS-TBC) with vacuum plasma sprayed (VPS) bond coats for exposures up to 5000 h in the temperature range of 950,1100,°C. This paper focuses on the Al depletion failure and how it relates to top coat spallation. [source] A thousand and one nova outburstsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007Noya Epelstain ABSTRACT A full nova cycle includes mass accretion, thermonuclear runaway resulting in outburst and mass-loss, and finally, decline. Resumed accretion starts a new cycle, leading to another outburst. Multicycle nova evolution models have been calculated over the past twenty years, the number being limited by numerical constraints. Here we present a long-term evolution code that enables a continuous calculation through an unlimited number of nova cycles for an unlimited evolution time, even up to 1.5 × 1010 yr. Starting with two sets of the three independent nova parameters , the white dwarf (WD) mass, the temperature of its isothermal core, and the rate of mass transfer on to it , we have followed the evolution of two models, with initial masses of 1 M, and 0.65 M, through over 1000 and over 3000 cycles, respectively. The accretion rate was assumed constant throughout each calculation: 10,11 M, yr,1 for the 1 M, WD, and 10,9 M, yr,1 for the 0.65 M, one. The initial temperatures were taken to be relatively high: 30 × 106 and 50 × 106 K, respectively, as they are likely to be at the onset of the outburst phase. The results show that although on the short-term consecutive outbursts are almost identical, on the long-term scale the characteristics change. This is mainly due to the changing core temperature, which decreases very similarly to that of a cooling WD for a time, but at a slower rate thereafter. As the WD's mass continually decreases, since both models lose more mass than they accrete, the central pressure decreases accordingly. The outbursts on the massive WD change gradually from fast to moderately fast, and the other characteristics (velocity, abundance ratios, isotopic ratios) change, too. Very slowly, a steady state is reached, where all characteristics, both in quiescence and in outburst, remain almost constant. For the less massive WD accreting at a high rate, outbursts are similar throughout the evolution. [source] Off-service Resident Education in the Emergency Department: Outline of a National Standardized CurriculumACADEMIC EMERGENCY MEDICINE, Issue 12 2009Chad S. Kessler MD Abstract Although many residency programs mandate at least one rotation in emergency medicine (EM), to the best of our knowledge, a standardized curriculum for emergency department (ED) rotations for "off-service" residents has not been developed. As a result, the experiences of these residents in the ED tend to vary during their rotations. To design an off-service EM curriculum, we adopted Kern's six-step approach to curriculum development as a conceptual framework. The resulting program encompasses clinical experience and didactic sessions through which residents are trained in core topics and skills. This knowledge will be applicable in the clinical settings in which residents will continue to train and ultimately practice their specialty. It is flexible enough to be applicable and implementable without being limited by resource availability or faculty strengths. [source] A general expression of the polarization factor for multi-diffraction processesACTA CRYSTALLOGRAPHICA SECTION A, Issue 3 2010Kiyoaki Tanaka A general expression of the polarization factor of multi-diffracted beams is formulated. By assigning the diffracted beam direction of each diffraction process as the y axis of a Cartesian coordinate system, the polarization factor of multi-diffraction processes can be easily calculated for polarized and unpolarized beams without being limited by the number of diffraction processes. The method can be applied to processes with more than three scattering events such as multiple diffraction and extinction. [source] Interplay between dipolar, stacking and hydrogen-bond interactions in the crystal structures of unsymmetrically substituted esters, amides and nitriles of (R,R)- O,O,-dibenzoyltartaric acidACTA CRYSTALLOGRAPHICA SECTION B, Issue 3 2001Urszula Rychlewska The compounds analysed are the O,O,-dibenzoyl derivatives of (R,R)-tartaric acid, asymmetrically substituted by ester, amide and nitrile groups. Benzoylation does not introduce drastic changes to the molecular conformation. All investigated molecules adopt the planar T conformation of the four-carbon chain with noticeably smaller departures from the ideal conformation than observed in the nonbenzoylated analogs. Primary and secondary amides always orient the C=O bond antiperiplanar (a) with respect to the nearest C*,O bond, while methylester groups adjust their conformation to that adopted by the amide substituent situated at the other end of the molecule. Tertiary amides and carboxyl groups place their carbonyls at the same side as the nearest C*,O bond (the s form), but often deviations from coplanarity of the two bonds are significant and higher than those observed in the nonbenzoylated series. The results presented demonstrate the importance of dipole/dipole interactions between CO and ,C*H groups in stabilizing the molecular conformation, and between carbonyl groups in stabilizing crystal packing of the molecules that lack classical hydrogen-bond donor groups. An illustration is provided as to how a small change in mutual orientation of molecules arranged in a close-packed fashion causes a change in the character of intermolecular interactions from van der Waals to sandwich stacking between the benzoyloxy phenyls, and to dipolar between the benzoyloxy carbonyls. Hydrogen-bonded molecules tend to orient in a head-to-tail mode; the head-to-head arrangement being limited to cases in which terminal carbonyl groups are situated at one side of the molecule. The orientation of the benzoyloxy substituents with respect to the carbon main chain is such that the (O=)C,O,C,H bond system often deviates significantly from planarity. [source] A computer experiment application to the design and optimization of a capacitive accelerometerAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 2 2009M. J. Alvarez Abstract An accelerometer is a transducer that allows measuring the acceleration acting on a structure. Physically, an accelerometer consists of a central mass suspended by thin and flexible arms and its performance is highly dependent on the dimensions of both the mass and the arms. The two most important parameters when evaluating the performance of these devices are the sensitivity and the operating frequency range (or bandwidth), the latter one being limited to of the resonance frequency. Therefore, it is very convenient to gain knowledge on how changes in the dimensions of the mass and arms affect the value of the natural frequency of the accelerometer, as it will provide guidelines to design accelerometers that fulfil frequency requirements of a specific application. A quadratic polynomial function of the natural logarithm of the frequency versus geometrical factors has been obtained using response surface methodology approach. A faced-centered cube design was used in the experimentation. The data were obtained conducting computer simulations using finite element design techniques. A better understanding of how these variables affect the value of frequency has been reached, which will be very useful for the device design purposes. Copyright © 2009 John Wiley & Sons, Ltd. [source] Below-ground biomass and productivity of a grazed site and a neighbouring ungrazed exclosure in a grassland in central ArgentinaAUSTRAL ECOLOGY, Issue 2 2004Eduardo Pucheta Abstract We estimated the below-ground net plant productivity (BNPP) of different biomass components in an intensively and continuously 45-ha grazed site and in a neighbouring exclosure ungrazed for 16 years for a natural mountain grassland in central Argentina. We measured approximately twice as much dead below-ground biomass in the grazed site as in the ungrazed site, with a strong concentration of total below-ground biomass towards the upper 10 cm of the soil layer in both sites. The main contribution to total live biomass was accounted for by very fine (<0.5 mm) and fine roots (0.5,1.0 mm) both at the grazed (79%) and at the ungrazed (81%) sites. We measured more dead biomass for almost all root components, more live biomass of rhizomes, tap roots and bulbs, and less live biomass of thicker roots (>1 mm) in the grazed site. The seasonal variation of total live below-ground biomass mainly reflected climate, with the growing season being limited to the warmer and wetter portion of the year, but such variation was higher in the grazed site. Using different methods of estimation of BNPP, we estimated maximum values of 1241 and 723 g m,2 year,1 for the grazed and ungrazed sites, respectively. We estimated that very fine root productivity was almost twice as high at the grazed site as at the ungrazed one, despite the fact that both sites had similar total live biomass, and root turnover rate was twofold at the grazed site. [source] | |||||||||||||