679 research outputs found

    Principle and Robotic Applications of Conical Scanning Method

    Get PDF
    We have proposed a surrounding environmental recognition method using conical scanning distance measurement for mobile robots. The conical scanning method has a high robustness against ambient light noise and its calculation cost is low. This report describes the principle of this method and the two implementations. The first application is the quadrupedal wheeled robot. The robot can recognize a stair in sight, approach to it and climb. A second application is the indoor-outdoor wheeled mobile robot. The robot can recognize its position and obstacles on floor from information of a laser range finder and a 3D ToF camera. The validity of this method was confirmed by these robotic applications

    Photoelectric Emission from Interstellar Dust: Grain Charging and Gas Heating

    Full text link
    We model the photoelectric emission from and charging of interstellar dust and obtain photoelectric gas heating efficiencies as a function of grain size and the relevant ambient conditions. Using realistic grain size distributions, we evaluate the net gas heating rate for various interstellar environments, and find less heating for dense regions characterized by R_V=5.5 than for diffuse regions with R_V=3.1. We provide fitting functions which reproduce our numerical results for photoelectric heating and recombination cooling for a wide range of interstellar conditions. In a separate paper we will examine the implications of these results for the thermal structure of the interstellar medium. Finally, we investigate the potential importance of photoelectric heating in H II regions, including the warm ionized medium. We find that photoelectric heating could be comparable to or exceed heating due to photoionization of H for high ratios of the radiation intensity to the gas density. We also find that photoelectric heating by dust can account for the observed variation of temperature with distance from the galactic midplane in the warm ionized medium.Comment: 50 pages, including 18 figures; corrected title and abstract field

    The role of cardiac troponin T quantity and function in cardiac development and dilated cardiomyopathy

    Get PDF
    Background: Hypertrophic (HCM) and dilated (DCM) cardiomyopathies results from sarcomeric protein mutations, including cardiac troponin T (cTnT, TNNT2). We determined whether TNNT2 mutations cause cardiomyopathies by altering cTnT function or quantity; whether the severity of DCM is related to the ratio of mutant to wildtype cTnT; whether Ca2+ desensitization occurs in DCM; and whether absence of cTnT impairs early embryonic cardiogenesis. Methods and Findings: We ablated Tnnt2 to produce heterozygous Tnnt2+/ mice, and crossbreeding produced homozygous null Tnnt2-/-embryos. We also generated transgenic mice overexpressing wildtype (TGWT) or DCM mutant (TGK210Δ) Tnnt2. Crossbreeding produced mice lacking one allele of Tnnt2, but carrying wildtype (Tnnt2+/-/TGWT) or mutant (Tnnt2+/-/TGK210Δ) transgenes. Tnnt2+/-mice relative to wildtype had significantly reduced transcript (0.82 ± 0.06 [SD] vs. 1.00 ± 0.12 arbitrary units; p = 0.025), but not protein (1.01 ± 0.20 vs. 1.00 ± 0.13 arbitrary units; p = 0.44). Tnnt2+/-mice had normal hearts (histology, mass, left ventricular end diastolic diameter [LVEDD], fractional shortening [FS]). Moreover, whereas Tnnt2+/-/ TGK210Δ mice had severe DCM, TGK210Δ mice had only mild DCM (FS 18 ± 4 vs. 29 ± 7%; p < 0.01). The difference in severity of DCM may be attributable to a greater ratio of mutant to wildtype Tnnt2 transcript in Tnnt2+/-/TGK210Δ relative to TGK210Δ mice (2.42±0.08, p = 0.03). Tnnt2+/-/TGK210Δ muscle showed Ca2+ desensitization (pCa50 = 5.34 ± 0.08 vs. 5.58 ± 0.03 at sarcomere length 1.9 μm. p<0.01), but no difference in maximum force generation. Day 9.5 Tnnt2-/-embryos had normally looped hearts, but thin ventricular walls, large pericardial effusions, noncontractile hearts, and severely disorganized sarcomeres. Conclusions: Absence of one Tnnt2 allele leads to a mild deficit in transcript but not protein, leading to a normal cardiac phenotype. DCM results from abnormal function of a mutant protein, which is associated with myocyte Ca2+ desensitization. The severity of DCM depends on the ratio of mutant to wildtype Tnnt2 transcript. cTnT is essential for sarcomere formation, but normal embryonic heart looping occurs without contractile activity. © 2008 Ahmad et al

    Developing cardiac and skeletal muscle share fast-skeletal myosin heavy chain and cardiac troponin-I expression

    Get PDF
    Skeletal muscle derived stem cells (MDSCs) transplanted into injured myocardium can differentiate into fast skeletal muscle specific myosin heavy chain (sk-fMHC) and cardiac specific troponin-I (cTn-I) positive cells sustaining recipient myocardial function. We have recently found that MDSCs differentiate into a cardiomyocyte phenotype within a three-dimensional gel bioreactor. It is generally accepted that terminally differentiated myocardium or skeletal muscle only express cTn-I or sk-fMHC, respectively. Studies have shown the presence of non-cardiac muscle proteins in the developing myocardium or cardiac proteins in pathological skeletal muscle. In the current study, we tested the hypothesis that normal developing myocardium and skeletal muscle transiently share both sk-fMHC and cTn-I proteins. Immunohistochemistry, western blot, and RT-PCR analyses were carried out in embryonic day 13 (ED13) and 20 (ED20), neonatal day 0 (ND0) and 4 (ND4), postnatal day 10 (PND10), and 8 week-old adult female Lewis rat ventricular myocardium and gastrocnemius muscle. Confocal laser microscopy revealed that sk-fMHC was expressed as a typical striated muscle pattern within ED13 ventricular myocardium, and the striated sk-fMHC expression was lost by ND4 and became negative in adult myocardium. cTn-I was not expressed as a typical striated muscle pattern throughout the myocardium until PND10. Western blot and RT-PCR analyses revealed that gene and protein expression patterns of cardiac and skeletal muscle transcription factors and sk-fMHC within ventricular myocardium and skeletal muscle were similar at ED20, and the expression patterns became cardiac or skeletal muscle specific during postnatal development. These findings provide new insight into cardiac muscle development and highlight previously unknown common developmental features of cardiac and skeletal muscle. © 2012 Clause et al

    Appraisal of Local Farmers’ Practices on Land Management for a Guideline of Agricultural Development in the Sahel Zone of Niger

    Get PDF
    In order to bridge a gap between research results and farmers’ needs for agricultural development in the Sahel, we made a study of traditional agricultural production systems derived from what we understood about indigenous knowledge (IK) of Sahelian farmers. The study was conducted in the western part of Niger, West Africa. IK was gathered from interviews among several villages of different generations. Then impartiality was verified. We obtained detailed information on land management and topographical features of farmland and devised a thorough local classification system. Statistical results showed that the obtained information was not significantly different among villages and generations. This result brought recognition that IK was a shared knowledge among local farmers in the study area. The study classified in detail a farmland that was directly or indirectly affected by household economy, the potential of natural resources like organic matter, and the relationship between agriculturalist and pastoralist. Understanding this context for soil fertility management at the village level makes it possible to assess the situation more appropriately than simply looking at actual practices, thereby helping to identify a problematic issue that concerns local farmers

    Response Of The Pigeonpea (Cajanus Cajan (L.) Millspaugh) To Nitrogen Application And Temporary Waterlogging

    Get PDF
    Short-duration pigeonpea (Cajanus cajan (L.) Millspaugh, cv. ICPL 87)) responded to applied N by increasing its shoot and rwt growth in a Vertisol field at ICRISAT Center in India. However. growth of shoot and roots was impaired and N concentration in leaf was decreased by short-ten (three days) waterlogging. During the recovery phase pigeonpa developed new adventitious rwts around the base of tap root with new nodules. Therefore waterlogged pigeonpea had higher total nodule activity than control plants and there were no differences in N concentration in ieaf at 40 days after the termination of waterlogging

    Rooting Behavior Of Intercropped Pigeonpea (Cajanus Cajan (L.) Millspaugh) And Sorghum (Sorghum Bicolor (L.) Moench)

    Get PDF
    The motlng pmnk of lndhrldual plgeonpea and sorghum plants were compared In monocmpplng and Intercmpplng, under different planting densltles, by use of a slmple dmulatlon appmach. Plgeonpea dld not show any characteristic advantages of root development over sorghum, pmbably due to the presence of a hard stony layer below 30 cm whlch consequently conflned roo1 pmllferatlon wlthln the sutfam layer of 8011. The rootlng depth was unaffected by the cropplng pattern. The root pmllfetatlon near the plant base Increased wlth plant age and was severely reduced by lntercmpplng In case of plgeonpea The lntercmpped sorghum had less mots lnltlally but attained a slmllar denslty as monocmpped sorghum at later stages. It Is demonstrated that root development Is conslderably affected by the planting denslty

    Identification of plant genetic resources with high potential contribution to soil fertility enhancement in the Sahel, with special interest in fallow vegetation

    Get PDF
    The sandy soil in the Sahel is characterized as low inherent fertility, that is, having nutrient deficiency (total N and available P), low organic matter and high risk of erosion. Under the concept of integrated soil fertility management (ISFM), possible contribution of natural inhabitant plants to the improvement of soil fertility in the Sahel was evaluated. A broad variation in δ 15N values was observed among the plant species commonly found in cropland and fallow land of the Sahelian zone. Annual leguminous herbs, Cassia mimosoides (Caesalpiniaceae) and Alysicarpus ovalifolius (Papilionaceae), had low δ 15N values, showing their higher dependency on biological nitrogen fixation. They will be efficiently utilized as an extensive means of soil fertility management, for example, through more encouraged incorporation into the fallow vegetation. Ctenium elegans, Eragrostis tremula and Schizachyrium exile, greatly dominating annual grass species in the fallow land, though their δ 15N values were high, would contribute to the soil fertility by supplying a significant amount of organic matte
    • …
    corecore