Science.gov

Sample records for segmental jumping translocation

  1. Jumping translocation in a newborn boy with dup(4q) and severe hydrops fetalis

    SciTech Connect

    Duval, E.; Enden, A. van den; Vanhaesebrouck, P.; Speleman, F.

    1994-08-15

    We report on the unusual cytogenetic findings in a newborn boy with severe hydrops fetalis. He has a mosaic for 2 unbalanced chromosome rearrangements: a der(18)t(4;18)(q31;q23) and a der(18)t(4;18)(q31;p11). As a result, this patient had a duplication of 4q31-qter in cells, and was possibly monosomic for the distal ends of 18p and 18q, respectively in the 2 cell lines. Sine in both rearrangements the same chromosome 4 segment was translocated to 2 different chromosome regions, we consider the present finding as a peculiar type of jumping translocation. 32 refs., 3 figs., 1 tab.

  2. Segmental and Kinetic Contributions in Vertical Jumps Performed with and without an Arm Swing

    ERIC Educational Resources Information Center

    Feltner, Michael E.; Bishop, Elijah J.; Perez, Cassandra M.

    2004-01-01

    To determine the contributions of the motions of the body segments to the vertical ground reaction force ([F.sub.z]), the joint torques produced by the leg muscles, and the time course of vertical velocity generation during a vertical jump, 15 men were videotaped performing countermovement vertical jumps from a force plate with and without an arm…

  3. [Identification of the 1RS-7DS.7DL wheat-rye small segment translocation lines].

    PubMed

    Jun, Li; Xinguo, Zhu; Hongshen, Wan; Qin, Wang; Zongxiang, Tang; Shulan, Fu; Zujun, Yang; Manyu, Yang; Wuyun, Yang

    2015-06-01

    Rye (Secale cereale L., RR) is a valuable genetic resource for the improvement of common wheat (Triticum aestivum L., AABBDD). Transferring alien rye genes into wheat by distant hybridization and automatic chromosome doubling is an important and efficient method to boost agronomic traits, disease resistance and widening the gene pool in wheat. In this study, an octoploid triticale CD-13 (AABBDDRR) was obtained via automatic chromosome doubling by crossing landrace Penganbaimaizi (T. aestivum L., AABBDD) and rye "Qinling rye" (S. cereale cv. Qinling, RR). GISH and FISH analyses indicated that CD-13 contained a 1RS-7DS.7DL wheat-rye small segment translocation chromosome. In order to transfer the 1RS-7DS small segment translocation into hexaploid wheat, 58 lines of the F5 inbred population from the cross CD-13 x Chuanmai 42 were screened for rye chromosome segments by GISH and FISH analyses. The results showed that 13 lines contained the 1RS-7DS.7DL small segment translocation chromosome by reciprocal translocation between 1RS and 7DS. These translocation lines carrying 1RS small rye alien segment were tested for the translocation breakpoints and the presence of a storage protein locus Sec-1. The Sec-1 locus was absent in the line 811, a stable 1RS-7DS.7DL small segment translocation line. The translocation breakpoint of 1RS-7DS.7DL of this line was located in the interval of IB267-IAG95 around the telomere of 1RS chromosome. Thousand-kernel weight of the line 811 was much higher than the parent CD-13, but not significantly different from Chuanmai 42. This indicated that 1RS-7DS.7DL small segment translocation had no negative effect on thousand-kernel weight in the genetic background of Chuanmai 42. The line with 1RS-7DS.7DL translocation chromosomes can be used as a new genetic material for further studies of valuable genes and their genetic effect on 1RS small segment. PMID:26351056

  4. Stop-and-move of a marginally hydrophobic segment translocating across the endoplasmic reticulum membrane.

    PubMed

    Onishi, Yukiko; Yamagishi, Marifu; Imai, Kenta; Fujita, Hidenobu; Kida, Yuichiro; Sakaguchi, Masao

    2013-09-01

    Many membrane proteins are cotranslationally integrated into the endoplasmic reticulum membrane via the protein-conducting channel, the so-called translocon. The hydrophobic transmembrane segment of the translocating nascent polypeptide chain stops at the translocon and then moves laterally into the membrane. Partitioning of the hydrophobic segment into the membrane is the primary determinant for membrane insertion. Here, we examined the behavior of a marginally hydrophobic segment at the translocon and found that its stop-translocation was greatly affected by the C-terminally attached ribosomes. The marginally hydrophobic segment first stops at the membrane and then moves into the lumen as long as the nascent chain is attached to translating ribosomes. When it is released from the ribosome by the termination codon, the marginally hydrophobic segment does not move. Puromycin or RNase treatment also suppressed movement. The movement was reversibly inhibited by high-salt conditions and irreversibly inhibited by ethylenediaminetetraacetic acid. There is an unstable state prior to the stable membrane insertion of the transmembrane segment. This characteristic state is maintained by the synthesizing ribosome. PMID:23747484

  5. Translocations of Chromosome End-Segments and Facultative Heterochromatin Promote Meiotic Ring Formation in Evening Primroses[W][OPEN

    PubMed Central

    Golczyk, Hieronim; Massouh, Amid; Greiner, Stephan

    2014-01-01

    Due to reciprocal chromosomal translocations, many species of Oenothera (evening primrose) form permanent multichromosomal meiotic rings. However, regular bivalent pairing is also observed. Chiasmata are restricted to chromosomal ends, which makes homologous recombination virtually undetectable. Genetic diversity is achieved by changing linkage relations of chromosomes in rings and bivalents via hybridization and reciprocal translocations. Although the structural prerequisite for this system is enigmatic, whole-arm translocations are widely assumed to be the mechanistic driving force. We demonstrate that this prerequisite is genome compartmentation into two epigenetically defined chromatin fractions. The first one facultatively condenses in cycling cells into chromocenters negative both for histone H3 dimethylated at lysine 4 and for C-banding, and forms huge condensed middle chromosome regions on prophase chromosomes. Remarkably, it decondenses in differentiating cells. The second fraction is euchromatin confined to distal chromosome segments, positive for histone H3 lysine 4 dimethylation and for histone H3 lysine 27 trimethylation. The end-segments are deprived of canonical telomeres but capped with constitutive heterochromatin. This genomic organization promotes translocation breakpoints between the two chromatin fractions, thus facilitating exchanges of end-segments. We challenge the whole-arm translocation hypothesis by demonstrating why reciprocal translocations of chromosomal end-segments should strongly promote meiotic rings and evolution toward permanent translocation heterozygosity. Reshuffled end-segments, each possessing a major crossover hot spot, can furthermore explain meiotic compatibility between genomes with different translocation histories. PMID:24681616

  6. Positive charges of translocating polypeptide chain retrieve an upstream marginal hydrophobic segment from the endoplasmic reticulum lumen to the translocon.

    PubMed

    Fujita, Hidenobu; Kida, Yuichiro; Hagiwara, Masatoshi; Morimoto, Fumiko; Sakaguchi, Masao

    2010-06-15

    Positively charged amino acid residues are well recognized topology determinants of membrane proteins. They contribute to the stop-translocation of a polypeptide translocating through the translocon and to determine the orientation of signal sequences penetrating the membrane. Here we analyzed the function of these positively charged residues during stop-translocation in vitro. Surprisingly, the positive charges facilitated membrane spanning of a marginally hydrophobic segment, even when separated from the hydrophobic segment by 70 residues. In this case, the hydrophobic segment was exposed to the lumen, and then the downstream positive charges triggered the segment to slide back into the membrane. The marginally hydrophobic segment spanned the membrane, but maintained access to the water environment. The positive charges not only fix the hydrophobic segment in the membrane at its flanking position, but also have a much more dynamic action than previously realized. PMID:20427573

  7. Characterization of thigh and shank segment angular velocity during jump landing tasks commonly used to evaluate risk for ACL injury.

    PubMed

    Dowling, Ariel V; Favre, Julien; Andriacchi, Thomas P

    2012-09-01

    The dynamic movements associated with anterior cruciate ligament (ACL) injury during jump landing suggest that limb segment angular velocity can provide important information for understanding the conditions that lead to an injury. Angular velocity measures could provide a quick and simple method of assessing injury risk without the constraints of a laboratory. The objective of this study was to assess the inter-subject variations and the sensitivity of the thigh and shank segment angular velocity in order to determine if these measures could be used to characterize jump landing mechanisms. Additionally, this study tested the correlation between angular velocity and the knee abduction moment. Thirty-six healthy participants (18 male) performed drop jumps with bilateral and unilateral landing. Thigh and shank angular velocities were measured by a wearable inertial-based system, and external knee moments were measured using a marker-based system. Discrete parameters were extracted from the data and compared between systems. For both jumping tasks, the angular velocity curves were well defined movement patterns with high inter-subject similarity in the sagittal plane and moderate to good similarity in the coronal and transverse planes. The angular velocity parameters were also able to detect differences between the two jumping tasks that were consistent across subjects. Furthermore, the coronal angular velocities were significantly correlated with the knee abduction moment (R of 0.28-0.51), which is a strong indicator of ACL injury risk. This study suggested that the thigh and shank angular velocities, which describe the angular dynamics of the movement, should be considered in future studies about ACL injury mechanisms. PMID:22938373

  8. NBCe1-A Transmembrane Segment 1 Lines the Ion Translocation Pathway.

    PubMed

    Zhu, Quansheng; Azimov, Rustam; Kao, Liyo; Newman, Debra; Liu, Weixin; Abuladze, Natalia; Pushkin, Alexander; Kurtz, Ira

    2009-03-27

    The electrogenic Na(+)/HCO(3)(-) cotransporter (NBCe1-A) transports sodium and bicarbonate across the basolateral membrane of the renal proximal tubule. In this study the structural requirement of transmembrane segment 1 (TM1) residues in mediating NBCe1-A transport was investigated. Twenty-five introduced cysteine mutants at positions Gln-424 to Gly-448 were tested for their sensitivity to the methanethiosulfonate reagents (2-sulfonatoethyl) methanethiosulfonate (MTSES), [2-(trimethylammonium)ethyl]methanethiosulfonate (MTSET), and (2-aminoethyl) methanethiosulfonate (MTSEA). Two mutants, T442C and A435C, showed 100 and 70% sensitivity, respectively, to inhibition by all the three methanethiosulfonate (MTS) reagents, I441C had >50% sensitivity to MTSET and MTSEA, and A428C had 50% sensitivity to MTSEA inhibition. A helical wheel plot showed that mutants T442C, A435C, and A428C are clustered on one face of TM1 within a 100 degrees arc. Topology analysis of TM1 with biotin maleimide and 2-((5(6)-tetramethylrhodamine)carboxylamino) ethyl methanethiosulfonate (MTS-TAMRA) revealed Thr-442 marks the C-terminal end of TM1 and that extracellular FGGLLG stretch is in a small aqueous-accessible cavity. Functional studies indicated that Thr-442 resides in a narrow region of the ion translocation pore with strong delta(-) helical dipole influence. Analysis of the corresponding residue of NBCe1-A-Thr-442 in AE1 (Thr-422) shows it is functionally insensitive to MTSES and unlabeled with MTS-TAMRA, indicating that AE1-TM1 is oriented differently from NBCe1-A. In summary, we have identified residues Thr-442, Ala-435, and Ala-428 in TM1 lining the ion translocation pore of NBCe1-A. Our findings are suggestive of a delta(-) helical dipole at the C-terminal end of TM1 involving Thr-442 that plays a critical role in the function of the cotransporter. PMID:19158093

  9. Characterization of wheat - Psathyrostachys huashanica small segment translocation line with enhanced kernels per spike and stripe rust resistance.

    PubMed

    Kang, Hou-Yang; Zhang, Zhi-Juan; Xu, Li-Li; Qi, Wei-Liang; Tang, Yao; Wang, Hao; Zhu, Wei; Li, Dai-Yan; Zeng, Jian; Wang, Yi; Fan, Xing; Sha, Li-Na; Zhang, Hai-Qin; Zhou, Yong-Hong

    2016-04-01

    Psathyrostachys huashanica Keng (2n = 2x = 14, NsNs), a distant wild relative of common wheat, possesses rich potentially valuable traits, such as disease resistance and more spikelets and kernels per spike, that could be useful for wheat genetic improvement. Development of wheat - P. huashanica translocation lines will facilitate its practical utilization in wheat breeding. In the present study, a wheat - P. huashanica small segmental translocation line, K-13-835-3, was isolated and characterized from the BC1F5 population of a cross between wheat - P. huashanica amphiploid PHW-SA and wheat cultivar CN16. Cytological studies showed that the mean chromosome configuration of K-13-835-3 at meiosis was 2n = 42 = 0.10 I + 19.43 II (ring) + 1.52 II (rod). GISH analyses indicated that chromosome composition of K-13-835-3 included 40 wheat chromosomes and a pair of wheat - P. huashanica translocation chromosomes. FISH results demonstrated that the small segment from an unidentified P. huashanica chromosome was translocated into wheat chromosome arm 5DS, proximal to the centromere region of 5DS. Compared with the cultivar wheat parent CN16, K-13-835-3 was highly resistant to stripe rust pathogens prevalent in China. Furthermore, spikelets and kernels per spike in K-13-835-3 were significantly higher than those of CN16 in two growing seasons. These results suggest that the desirable genes from P. huashanica were successfully transferred into CN16 background. This translocation line could be used as novel germplasm for high-yield and, eventually, resistant cultivar breeding. PMID:26961208

  10. Volcanism, jump and propagation on the Sheba ridge, eastern Gulf of Aden: segmentation evolution and implications for oceanic accretion processes

    NASA Astrophysics Data System (ADS)

    d'Acremont, Elia; Leroy, Sylvie; Maia, Marcia; Gente, Pascal; Autin, Julia

    2010-02-01

    The rifting between Arabia and Somalia, which started around 35 Ma, was followed by oceanic accretion from at least 17.6 Ma leading to the formation of the present-day Gulf of Aden. Bathymetric, gravity and magnetic data from the Encens-Sheba cruise are used to constrain the structure and segmentation of the oceanic basin separating the conjugate continental margins in the eastern part of the Gulf of Aden between 51°E and 55.5°E. Data analysis reveals that the oceanic domain along this ridge section is divided into two distinct areas. The Eastern area is characterized by a shorter wavelength variation of the axial segmentation and an extremely thin oceanic crust. In the western segment, a thicker oceanic crust suggests a high melt supply. This supply is probably due to an off-axis melting anomaly located below the southern flank of the Sheba ridge, 75 km east of the major Alula-Fartak transform fault. This suggests that the axial morphology is produced by a combination of factors, including spreading rate, melt supply and the edge effect of the Alula-Fartak transform fault, as well as the proximity of the continental margin. The oceanic domains have undergone two distinct phases of accretion since the onset of seafloor spreading, with a shift around 11 Ma. At that time, the ridge jumped southwards, in response to the melting anomaly. Propagating ridges were triggered by the melting activity, and propagated both eastward and westward. The influence of the melting anomaly on the ridges decreased, stopping their propagation since less than 9 Ma. From that time up to the present, the N025°E-trending Socotra transform fault developed in association with the formation of the N115°E-trending segment #2. In recent times, a counter-clockwise rotation of the stress field associated with kinematic changes could explain the structural morphology of the Alula-Fartak and Socotra-Hadbeen fracture zones.

  11. Inner Segment Remodeling and Mitochondrial Translocation in Cone Photoreceptors in Age-Related Macular Degeneration With Outer Retinal Tubulation

    PubMed Central

    Litts, Katie M.; Messinger, Jeffrey D.; Freund, K. Bailey; Zhang, Yuhua; Curcio, Christine A.

    2015-01-01

    Purpose. To quantify impressions of mitochondrial translocation in degenerating cones and to determine the nature of accumulated material in the subretinal space with apparent inner segment (IS)-like features by examining cone IS ultrastructure. Methods. Human donor eyes with advanced age-related macular degeneration (AMD) were screened for outer retinal tubulation (ORT) in macula-wide, high-resolution digital sections. Degenerating cones inside ORT (ORT cones) and outside ORT (non-ORT cones) from AMD eyes and unaffected cones in age-matched control eyes were imaged using transmission electron microscopy. The distances of mitochondria to the external limiting membrane (ELM), cone IS length, and cone IS width at the ELM were measured. Results. Outer retinal tubulation and non-ORT cones lose outer segments (OS), followed by shortening of IS and mitochondria. In non-ORT cones, IS broaden. Outer retinal tubulation and non-ORT cone IS myoids become undetectable due to mitochondria redistribution toward the nucleus. Some ORT cones were found lacking IS and containing mitochondria in the outer fiber (between soma and ELM). Unlike long, thin IS mitochondria in control cones, ORT and non-ORT IS mitochondria are ovoid or reniform. Shed IS, some containing mitochondria, were found in the subretinal space. Conclusions. In AMD, macula cones exhibit loss of detectable myoid due to IS shortening in addition to OS loss, as described. Mitochondria shrink and translocate toward the nucleus. As reflectivity sources, translocating mitochondria may be detectable using in vivo imaging to monitor photoreceptor degeneration in retinal disorders. These results improve the knowledge basis for interpreting high-resolution clinical retinal imaging. PMID:25758815

  12. Cytogenetic and molecular identification of small-segment chromosome translocation lines from wheat-rye substitution lines to create wheat germplasm with beneficial traits

    PubMed Central

    Song, Wei-Fu; Ding, Hai-Yan; Zhang, Xiao-Mei; Li, Ji-Lin; Xiao, Zhi-Min; Xin, Wen-Li; Song, Qing-Jie; Zhao, Hai-Bin; Zhang, Yan-Bin; Zhang, Chun-Li

    2014-01-01

    ABSTRACT Intergeneric crop plant hybrid lines with small-segment chromosome translocations are very useful in plant genetic research and breeding. In this study, to create small-segment chromosome translocations with beneficial agronomic characters, the progeny of wheat-rye substitution lines 5R/5A and 6R/6A were selected from generations F2 to F5 for rye-specific characteristics. A PCR primer and specific simple sequence repeat marker for rye were used in F5 populations to detect rye chromatin and to amplify a specific chromosome band in six translocation lines (06-6-5, 06-6-6, 06-6-9, 6-26-1, 7-23, and 7-33). Fragment pSc119.1 cloned from 7-33 had 99% homology with the big ear gene sequence (GenBank AF512607.1) in wheat. The six lines were further characterized via pollen mother cell meiosis analysis for genetic stability, and chromosome C-banding and genomic in situ hybridization for rye chromatin. The results show that line 7-33 was still within the 5R/5A substitution lines and possessed the big ear gene. The other lines all contained small-segment rye chromosome translocations. The results indicated that substitution line hybridization is an effective method for creating small-segment chromosome translocations with useful agronomic traits. Trials for these six wheat-rye translocation lines are justified because they possess many important stably-inherited agronomic characters, including disease resistance and improved yield. PMID:26019483

  13. Duplication of segment 1p21 following paternal insertional translocation, ins(6;1)(q25;p13.3p22.1)

    PubMed Central

    Utkus, A.; Sorokina, I.; Kucinskas, V.; Rothlisberger, B.; Balmer, D.; Brecevic, L.; Schinzel, A.

    1999-01-01

    A moderately mentally retarded 3 year old boy showed minor anomalies including a prominent forehead and flat occiput, exophthalmos, large and prominent ears, high arched palate, umbilical hernia, sacral dimple, and irregular position of the toes. Cardiac sonography disclosed a chorda running through the left ventricle. Cytogenetic investigation of the family showed a balanced insertional translocation of segment 1p13→p22 into distal 6q in the father which had led, through unbalanced segregation, to duplication of 1p13.3→p22.1 in the proband. Familial duplication of such a small interstitial segment of 1p has not been reported previously, and the paucity of abnormal physical findings in the proband compared to previous patients with a similar aberration is remarkable. 


Keywords: chromosome duplication 1p; dual colour FISH; unbalanced insertional translocation PMID:9950373

  14. Duplication of segment 1p21 following paternal insertional translocation, ins(6;1)(q25;p13.3p22.1).

    PubMed

    Utkus, A; Sorokina, I; Kucinskas, V; Röthlisberger, B; Balmer, D; Brecevic, L; Schinzel, A

    1999-01-01

    A moderately mentally retarded 3 year old boy showed minor anomalies including a prominent forehead and flat occiput, exophthalmos, large and prominent ears, high arched palate, umbilical hernia, sacral dimple, and irregular position of the toes. Cardiac sonography disclosed a chorda running through the left ventricle. Cytogenetic investigation of the family showed a balanced insertional translocation of segment 1p13-->p22 into distal 6q in the father which had led, through unbalanced segregation, to duplication of 1p13.3-->p22.1 in the proband. Familial duplication of such a small interstitial segment of 1p has not been reported previously, and the paucity of abnormal physical findings in the proband compared to previous patients with a similar aberration is remarkable. PMID:9950373

  15. Jumping hoops

    NASA Astrophysics Data System (ADS)

    Yang, Eunjin; Kim, Ho-Young

    2012-01-01

    We investigate the dynamics of an elastic hoop as a model of the jumps of small insects. During a jump the initial elastic strain energy is converted to translational, gravitational, and vibrational energy, and is dissipated by interaction with the floor and the ambient air. We show that the strain energy is initially divided into translational, vibrational, and dissipation energies with a ratio that is constant regardless of the dimension, initial deflection, and the properties of a hoop. This novel result enables us to accurately predict the maximum jump height of a hoop with known initial conditions and drag coefficient without resorting to a numerical computation. Our model reduces the optimization of the hoop geometry for maximizing the jump height to a simple algebraic problem.

  16. Segments.

    ERIC Educational Resources Information Center

    Zemsky, Robert; Shaman, Susan; Shapiro, Daniel B.

    2001-01-01

    Presents a market taxonomy for higher education, including what it reveals about the structure of the market, the model's technical attributes, and its capacity to explain pricing behavior. Details the identification of the principle seams separating one market segment from another and how student aspirations help to organize the market, making…

  17. Reciprocal translocations

    SciTech Connect

    1993-12-31

    Chapter 26, describes reciprocal translocations of chromosomes: their occurrence, breakpoints, and multiple rearrangements. In addition, phenotypes of balanced and unbalanced translocation carriers and fetal death are discussed. Examples of translocation families are given. Meiosis and genetic risk in translocation carriers is presented. Finally, sperm chromosomes in meiotic segregation analysis is mentioned. 39 refs., 3 figs., 1 tab.

  18. Supersonic Jump

    ERIC Educational Resources Information Center

    Muller, Andreas

    2013-01-01

    On October 14,2012, Felix Baumgartner, an Austrian sky-diver, set some new world records for his discipline. Jumping from a height of about 39 km, he reached a top speed of 1342 km/h, becoming the first human being to break the sound barrier in free fall. In order to understand some essential physics aspects of this remarkable feat, we wonder why…

  19. Epitaxial jumps

    NASA Astrophysics Data System (ADS)

    Stura, Enrico A.; Charbonnier, Jean-Baptiste; Taussig, Michael J.

    1999-01-01

    By a combination of seeding and changing the growth medium new crystal forms may be obtained. The procedure is called an epitaxial jump. The seeds used in the seeding are from crystals of the same or related protein. For example, seeding followed by an increase in precipitant concentration has given higher diffracting crystals of the complex between tissue factor, factor VIIa and the inhibitor 5L15. For both an anti-steroid antibody fragment and human placental alkaline phosphatase a polymorph was obtained by changing a low molecular weight polyethylene glycol (PEG) with one of a higher molecular weight. In the first case, in one direction and in the latter case, in the other direction. A change of conformation could also have contributed to this. A DsbA mutant illustrates how such changes, result in a different packing from that for the wild-type. Seeding from crystals of wild-type protein yields crystals which appear to be morphologically different from both the wild-type and mutant crystal forms.

  20. Simulations of Polymer Translocation

    NASA Astrophysics Data System (ADS)

    Vocks, H.

    2008-07-01

    Transport of molecules across membranes is an essential mechanism for life processes. These molecules are often long, and the pores in the membranes are too narrow for the molecules to pass through as a single unit. In such circumstances, the molecules have to squeeze -- i.e., translocate -- themselves through the pores. DNA, RNA and proteins are such naturally occuring long molecules in a variety of biological processes. Understandably, the process of translocation has been an active topic of current research: not only because it is a cornerstone of many biological processes, but also due to its relevance for practical applications. Translocation is a complicated process in living organisms -- the presence of chaperone molecules, pH, chemical potential gradients, and assisting molecular motors strongly influence its dynamics. Consequently, the translocation process has been empirically studied in great variety in biological literature. Study of translocation as a biophysical process is more recent. Herein, the polymer is simplified to a sequentially connected string of N monomers as it passes through a narrow pore on a membrane. The quantities of interest are the typical time scale for the polymer to leave a confining cell (the ``escape of a polymer from a vesicle'' time scale), and the typical time scale the polymer spends in the pore (the ``dwell'' time scale) as a function of N and other parameters like membrane thickness, membrane adsorption, electrochemical potential gradient, etc. Our research is focused on computer simulations of translocation. Since our main interest is in the scaling properties, we use a highly simplified description of the translocation process. The polymer is described as a self-avoiding walk on a lattice, and its dynamics consists of single-monomer jumps from one lattice site to another neighboring one. Since we have a very efficient program to simulate such polymer dynamics, which we decribe in Chapter 2, we can perform long

  1. Continental rift jumps

    NASA Astrophysics Data System (ADS)

    Wood, Charles A.

    1983-05-01

    Continental rift jumps, analogous to jumps of oceanic spreading ridges, are here proposed to be common. Good examples exist in Iceland and Afar (both transitional from ridge to rift jumps), West Africa (Benue Trough and Cameroon Volcanic Line), and Kenya. Indeed, the Kenya rift appears to have jumped c. 100 km eastward c. 10 m.y. ago and is currently jumping further to the east. Possible jumps exist in the Baikal rift, the Limagne-Bresse rift pair, and parallel to ancient continental margins (e.g., the Triassic basins of the eastern U.S. to Baltimore Canyon and Georges Bank). Continental rifts jump distances that are approximately equal to local lithosphere thickness, suggesting that jumped rifts are controlled by lithosphere fracturing, but there appears to be no reason for the fracturing except migration of hot spots.

  2. Optimizing Thomson's jumping ring

    NASA Astrophysics Data System (ADS)

    Tjossem, Paul J. H.; Brost, Elizabeth C.

    2011-04-01

    The height to which rings will jump in a Thomson jumping ring apparatus is the central question posed by this popular lecture demonstration. We develop a simple time-averaged inductive-phase-lag model for the dependence of the jump height on the ring material, its mass, and temperature and apply it to measurements of the jump height for a set of rings made by slicing copper and aluminum alloy pipe into varying lengths. The data confirm a peak jump height that grows, narrows, and shifts to smaller optimal mass when the rings are cooled to 77 K. The model explains the ratio of the cooled/warm jump heights for a given ring, the reduction in optimal mass as the ring is cooled, and the shape of the mass resonance. The ring that jumps the highest is found to have a characteristic resistance equal to the inductive reactance of the set of rings.

  3. Robertsonian translocations

    SciTech Connect

    1993-12-31

    Chapter 27, describes the occurrence of Robertsonian translocations (RTs), which refer to the recombination of whole chromosome arms, in both monocentric and dicentric chromosomes. The nonrandom participation of acrocentric chromosomes in RTs is documented by various methods, including unbiased ascertainment and ascertainment through trisomy, infertility, unspecified mental retardation, and Prader-Willi syndrome. Causes of nonrandom participation of chromosomes in RTs is presented, as are the following topics: segregation in carriers of RTs and segregation in sperm cells of RT carriers, interchromosomal effects and conclusions. 48 refs., 3 figs., 2 tabs.

  4. A cockroach that jumps.

    PubMed

    Picker, Mike; Colville, Jonathan F; Burrows, Malcolm

    2012-06-23

    We report on a newly discovered cockroach (Saltoblattella montistabularis) from South Africa, which jumps and therefore differs from all other extant cockroaches that have a scuttling locomotion. In its natural shrubland habitat, jumping and hopping accounted for 71 per cent of locomotory activity. Jumps are powered by rapid and synchronous extension of the hind legs that are twice the length of the other legs and make up 10 per cent of the body weight. In high-speed images of the best jumps the body was accelerated in 10 ms to a take-off velocity of 2.1 m s(-1) so that the cockroach experienced the equivalent of 23 times gravity while leaping a forward distance of 48 times its body length. Such jumps required 38 µJ of energy, a power output of 3.4 mW and exerted a ground reaction force through both hind legs of 4 mN. The large hind legs have grooved femora into which the tibiae engage fully in advance of a jump, and have resilin, an elastic protein, at the femoro-tibial joint. The extensor tibiae muscles contracted for 224 ms before the hind legs moved, indicating that energy must be stored and then released suddenly in a catapult action to propel a jump. Overall, the jumping mechanisms and anatomical features show remarkable convergence with those of grasshoppers with whom they share their habitat and which they rival in jumping performance. PMID:22158737

  5. Optimal Ski Jump

    ERIC Educational Resources Information Center

    Rebilas, Krzysztof

    2013-01-01

    Consider a skier who goes down a takeoff ramp, attains a speed "V", and jumps, attempting to land as far as possible down the hill below (Fig. 1). At the moment of takeoff the angle between the skier's velocity and the horizontal is [alpha]. What is the optimal angle [alpha] that makes the jump the longest possible for the fixed magnitude of the…

  6. Jumping Good Fun

    ERIC Educational Resources Information Center

    Nye, Susan B.

    2010-01-01

    Jumping rope is an activity that can be fun and enjoyable for all students. It requires minimal activity space, can be performed individually or in small groups, and is an inexpensive way to engage students in a lifelong physical activity. Jumping rope is commonly used by coaches and athletes for training purposes to improve aerobic endurance,…

  7. Quantum walk with jumps

    NASA Astrophysics Data System (ADS)

    Lavička, H.; Potoček, V.; Kiss, T.; Lutz, E.; Jex, I.

    2011-09-01

    We analyze a special class of 1-D quantum walks (QWs) realized using optical multi-ports. We assume non-perfect multi-ports showing errors in the connectivity, i.e. with a small probability the multi-ports can connect not to their nearest neighbor but to another multi-port at a fixed distance - we call this a jump. We study two cases of QW with jumps where multiple displacements can emerge at one timestep. The first case assumes time-correlated jumps (static disorder). In the second case, we choose the positions of jumps randomly in time (dynamic disorder). The probability distributions of position of the QW walker in both instances differ significantly: dynamic disorder leads to a Gaussian-like distribution, while for static disorder we find two distinct behaviors depending on the parity of jump size. In the case of even-sized jumps, the distribution exhibits a three-peak profile around the position of the initial excitation, whereas the probability distribution in the odd case follows a Laplace-like discrete distribution modulated by additional (exponential) peaks for long times. Finally, our numerical results indicate that by an appropriate mapping a universal functional behavior of the variance of the long-time probability distribution can be revealed with respect to the scaled average of jump size.

  8. How coalescing droplets jump.

    PubMed

    Enright, Ryan; Miljkovic, Nenad; Sprittles, James; Nolan, Kevin; Mitchell, Robert; Wang, Evelyn N

    2014-10-28

    Surface engineering at the nanoscale is a rapidly developing field that promises to impact a range of applications including energy production, water desalination, self-cleaning and anti-icing surfaces, thermal management of electronics, microfluidic platforms, and environmental pollution control. As the area advances, more detailed insights of dynamic wetting interactions on these surfaces are needed. In particular, the coalescence of two or more droplets on ultra-low adhesion surfaces leads to droplet jumping. Here we show, through detailed measurements of jumping droplets during water condensation coupled with numerical simulations of binary droplet coalescence, that this process is fundamentally inefficient with only a small fraction of the available excess surface energy (≲ 6%) convertible into translational kinetic energy. These findings clarify the role of internal fluid dynamics during the jumping droplet coalescence process and underpin the development of systems that can harness jumping droplets for a wide range of applications. PMID:25171210

  9. Jump for the Moon

    NASA Video Gallery

    Increase bone strength and improve heart and other muscle endurance by performing jump training with a rope, both while stationary and moving. The Train Like an Astronaut project uses the excitemen...

  10. Suicide by Jumping.

    PubMed

    Beautrais, Annette

    2007-01-01

    Research on suicide by jumping is summarized. The incidence of suicide by this method varies but tends to be higher in cities, city states, or countries that have extensive high-rise housing. Most suicides by jumping occur from high-rise residential housing units. However, our knowledge about suicide by jumping tends to be limited to a small number of reports from sites, often bridges, which become well-known as places from which to take one's life. Media reports of newsworthy suicides from these sites appear to encourage imitative behavior. Prevention strategies have focused upon limiting suicides from iconic sites by surveillance, barriers, muted media reporting, and signage offering help and telephone hotlines. A small number of studies provides evidence that installing barriers at popular jumping sites reduces suicides from those sites. There are few reports of efforts to reduce suicides from high-rise residential buildings. PMID:26212196

  11. Egg Bungee Jump!

    ERIC Educational Resources Information Center

    Fitzgerald, Mike; Brand, Lance

    2004-01-01

    In this article, the authors present an egg bungee jumping activity. This activity introduces students to ways that engineers might apply calculations of failure to meet a challenge. Students are required to use common, everyday materials such as rubber bands, string, plastic bags, and eggs. They will apply technological problem solving, material…

  12. Jump into Action

    ERIC Educational Resources Information Center

    Ball, Stephen; Cohen, Ann; Meyer, Margaret

    2012-01-01

    Jump Into Action (JIA) is a school-based team-taught program to help fifth-grade students make healthy food choices and be more active. The JIA team (physical education teacher, classroom teacher, school nurse, and parent) work together to provide a supportive environment as students set goals to improve food choices and increase activity.…

  13. Walking and jumping spores

    NASA Astrophysics Data System (ADS)

    Marmottant, Philippe

    2012-02-01

    The Equisetum plants, more commonly called ``horsetail,'' emit 50-microns spores that are spherical in shape and present four hygroscopic arms. Under high humidity, the arms are retracted. But under lower humidity, less than 70%, the four arms deploy beautifully. With time-lapse image recordings, we show that under repeated cycles of dry and high humidity, the spores behave as random walkers, since they move by about their size in a different direction at every cycle. The process is apparently stochastic because of the complex shape of the arms and hysteretic friction of the arms on the ground. For some spores, a decrease in humidity level results in very fast jumps, the spores taking off at a typical velocity of a meter per second, as recorded on high-speed camera. With these jumps, they reach centimetric elevations, much larger than their size. The physical mechanism at the root of these ``Levy-flight'' jumps is still under investigation. The walking and jumping phenomena thus provide motility, which we believe is helpful for the understanding of the biological dispersion of the spores. It could also bring biomimetic inspiration to engineer new motile elastic structures.

  14. The Jumping Ring Experiment

    ERIC Educational Resources Information Center

    Baylie, M.; Ford, P. J.; Mathlin, G. P.; Palmer, C.

    2009-01-01

    The jumping ring experiment has become central to liquid nitrogen shows given as part of the outreach and open day activities carried out within the University of Bath. The basic principles of the experiment are described as well as the effect of changing the geometry of the rings and their metallurgical state. In general, aluminium rings are…

  15. Egg Bungee Jump

    ERIC Educational Resources Information Center

    Tretter, Thomas

    2005-01-01

    In the spirit of the National Science Education Standards (NRC 1996), many teachers attempt to have their students experience science in a constructivist, inquiry-oriented manner. The egg bungee jump activity will certainly support that mode of teaching, and has the added benefit of providing a concrete context within which students can explore…

  16. Jump with Jill

    ERIC Educational Resources Information Center

    Henderson, Nancy

    2010-01-01

    This article profiles Jill Jayne, who was working as a registered nutritionist in the New York City public school system when she was assigned to a group of 25 urban students in an after-school program in East Harlem. In the spring of 2006, Jayne took her "Jump With Jill" show to the streets outside Central Park, collected tips in a tin pot and,…

  17. Jumping hoops on water

    NASA Astrophysics Data System (ADS)

    Yang, Eunjin; Kim, Ho-Young

    2015-11-01

    Small aquatic arthropods, such as water striders and fishing spiders, are able to jump off water to a height several times their body length. Inspired by the unique biological motility on water, we study a simple model using a flexible hoop to provide fundamental understanding and a mimicking principle of small jumpers on water. Behavior of a hoop on water, which is coated with superhydrophobic particles and initially bent into an ellipse from an equilibrium circular shape, is visualized with a high speed camera upon launching it into air by releasing its initial elastic strain energy. We observe that jumping of our hoops is dominated by the dynamic pressure of water rather than surface tension, and thus it corresponds to the dynamic condition experienced by fishing spiders. We calculate the reaction forces provided by water adopting the unsteady Bernoulli equation as well as the momentum loss into liquid inertia and viscous friction. Our analysis allows us to predict the jumping efficiency of the hoop on water in comparison to that on ground, and to discuss the evolutionary pressure rendering fishing spiders select such dynamic behavior.

  18. DC-Powered Jumping Ring

    ERIC Educational Resources Information Center

    Jeffery, Rondo N.; Farhang, Amiri

    2016-01-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant…

  19. Particle jumps in structural glasses.

    PubMed

    Ciamarra, Massimo Pica; Pastore, Raffaele; Coniglio, Antonio

    2016-01-14

    Particles in structural glasses rattle around temporary equilibrium positions, that seldom change through a process which is much faster than the relaxation time, known as particle jump. Since the relaxation of the system is due to the accumulation of many such jumps, it could be possible to connect the single particle short time motion to the macroscopic relaxation by understanding the features of the jump dynamics. Here we review recent results in this research direction, clarifying the features of particle jumps that have been understood and those that are still under investigation, and examining the role of particle jumps in different theories of the glass transition. PMID:26481331

  20. Driven Polymer Translocation into a Crosslinked Gel

    NASA Astrophysics Data System (ADS)

    Sean, David; Slater, Gary

    2015-03-01

    In a typical polymer translocation setup, a thin membrane is used to separate two chambers and a polyelectrolyte is driven by an electric field to translocate from one side of the membrane to the other via a small nanopore. However, the high translocation rate that results from the forces required to drive this process makes optical and/or electrical analysis of the translocating polymer challenging. Using coarse-grained Langevin Dynamics simulations we investigate how the translocation process can be slowed down by placing a crosslinked gel on the trans-side of the membrane. Since the driving electric field is localized in the neighborhood of the nanopore, electrophoretic migration is only achieved by a ``pushing'' action from the polymer segment residing in the nanopore. For the case of a flexible polymer we find that the polymer fills the gel pores via multiple ``herniation'' processes, whereas for a semi-flexible chain in a tight gel there are no hernias and the polymer follows a smooth curvilinear path. Moreover, for the case of a semi-flexible polymer the gel makes the translocation process more uniform by reducing the acceleration at the end of the process.

  1. Exploring Lightning Jump Characteristics

    NASA Technical Reports Server (NTRS)

    Chronis, Themis; Carey, Larry D.; Schultz, Christopher J.; Schultz, Elise; Calhoun, Kristin; Goodman, Steven J.

    2014-01-01

    This study is concerned with the characteristics of storms exhibiting an abrupt temporal increase in the total lightning flash rate (i.e., lightning jump, LJ). An automated storm tracking method is used to identify storm "clusters" and total lightning activity from three different lightning detection systems over Oklahoma, northern Alabama and Washington, D.C. On average and for different employed thresholds, the clusters that encompass at least one LJ (LJ1) last longer, relate to higher Maximum Expected Size of Hail, Vertical Integrated Liquid and lightning flash rates (area-normalized) than the clusters that did not exhibit any LJ (LJ0). The respective mean values for LJ1 (LJ0) clusters are 80 min (35 min), 14 mm (8 mm), 25 kg per square meter (18 kg per square meter) and 0.05 flash per min per square kilometer (0.01 flash per min per square kilometer). Furthermore, the LJ1 clusters are also characterized by slower decaying autocorrelation functions, a result that implies a less "random" behavior in the temporal flash rate evolution. In addition, the temporal occurrence of the last LJ provides an estimate of the time remaining to the storm's dissipation. Depending of the LJ strength (i.e., varying thresholds), these values typically range between 20-60 min, with stronger jumps indicating more time until storm decay. This study's results support the hypothesis that the LJ is a proxy for the storm's kinematic and microphysical state rather than a coincidental value.

  2. Thersites: a `jumping' Trojan?

    NASA Astrophysics Data System (ADS)

    Tsiganis, K.; Dvorak, R.; Pilat-Lohinger, E.

    2000-02-01

    In this paper, we examine the dynamical evolution of the asteroid (1868) Thersites, a member of the Trojan belt. Thersites is librating around the Lagrangian point L_4, following, however, a chaotic orbit. The equations of motion for Thersites as well as for a distribution of neighboring initial conditions are integrated numerically for 50 million years in the Outer Solar System model (OSS), which consists of the Sun and the four giant planets. Our results indicate that the probability that this asteroid will eventually escape from the Trojan swarm is rather high. In fact, 20% from our initial distribution escaped within the integration time. Many of the remaining ones also show characteristic `jumps' in the orbital elements, especially the inclination. Secular resonances involving the nodes of the outer planets are found to be responsible for this chaotic behavior. The width of libration and eccentricity values that lead to grossly unstable orbits are calculated and compared with previously known results on the stability of the Trojans. Finally, a very interesting behavior has been observed for one of the escaping asteroids as he `jumped' from L_4 to L_5 where he remained performing a highly inclined libration for ~ 2 Myrs before escaping from the Trojan swarm. According to Homer, Thersites was not only the ugliest of all Greeks that took part in the Trojan war, but also had the most intolerable personality. His nasty habit of making fun of everybody cost him his life, as the last person for whom he spoke ironically about was Achilles, the mightiest warrior of all Greeks, who killed Thersites with just one punch!

  3. Kinematics of the long jump

    NASA Astrophysics Data System (ADS)

    Tan, Ajun; Zumerchik, John

    2000-03-01

    The long jump is one of the most natural events in track and field athletics. The jumper is allowed to run a 40-m runway at top speed and jump as far as possible from a takeoff board. It is an event in which the natural ability of the athlete plays a large role and technique is of secondary importance. The two most important factors in the long jump are speed and elevation.

  4. Physiology in conservation translocations

    PubMed Central

    Tarszisz, Esther; Dickman, Christopher R.; Munn, Adam J.

    2014-01-01

    Conservation translocations aim to restore species to their indigenous ranges, protect populations from threats and/or reinstate ecosystem functions. They are particularly important for the conservation and management of rare and threatened species. Despite tremendous efforts and advancement in recent years, animal conservation translocations generally have variable success, and the reasons for this are often uncertain. We suggest that when little is known about the physiology and wellbeing of individuals either before or after release, it will be difficult to determine their likelihood of survival, and this could limit advancements in the science of translocations for conservation. In this regard, we argue that physiology offers novel approaches that could substantially improve translocations and associated practices. As a discipline, it is apparent that physiology may be undervalued, perhaps because of the invasive nature of some physiological measurement techniques (e.g. sampling body fluids, surgical implantation). We examined 232 publications that dealt with translocations of terrestrial vertebrates and aquatic mammals and, defining ‘success’ as high or low, determined how many of these studies explicitly incorporated physiological aspects into their protocols and monitoring. From this review, it is apparent that physiological evaluation before and after animal releases could progress and improve translocation/reintroduction successes. We propose a suite of physiological measures, in addition to animal health indices, for assisting conservation translocations over the short term and also for longer term post-release monitoring. Perhaps most importantly, we argue that the incorporation of physiological assessments of animals at all stages of translocation can have important welfare implications by helping to reduce the total number of animals used. Physiological indicators can also help to refine conservation translocation methods. These approaches fall

  5. Chaperone-assisted translocation of flexible polymers in three dimensions

    NASA Astrophysics Data System (ADS)

    Suhonen, P. M.; Linna, R. P.

    2016-01-01

    Polymer translocation through a nanometer-scale pore assisted by chaperones binding to the polymer is a process encountered in vivo for proteins. Studying the relevant models by computer simulations is computationally demanding. Accordingly, previous studies are either for stiff polymers in three dimensions or flexible polymers in two dimensions. Here, we study chaperone-assisted translocation of flexible polymers in three dimensions using Langevin dynamics. We show that differences in binding mechanisms, more specifically, whether a chaperone can bind to a single site or multiple sites on the polymer, lead to substantial differences in translocation dynamics in three dimensions. We show that the single-binding mode leads to dynamics that is very much like that in the constant-force driven translocation and accordingly mainly determined by tension propagation on the cis side. We obtain β ≈1.26 for the exponent for the scaling of the translocation time with polymer length. This fairly low value can be explained by the additional friction due to binding particles. The multiple-site binding leads to translocation the dynamics of which is mainly determined by the trans side. For this process we obtain β ≈1.36 . This value can be explained by our derivation of β =4 /3 for constant-bias translocation, where translocated polymer segments form a globule on the trans side. Our results pave the way for understanding and utilizing chaperone-assisted translocation where variations in microscopic details lead to rich variations in the emerging dynamics.

  6. Physics and the Vertical Jump

    ERIC Educational Resources Information Center

    Offenbacher, Elmer L.

    1970-01-01

    The physics of vertical jumping is described as an interesting illustration for motivating students in a general physics course to master the kinematics and dynamics of one dimensional motion. The author suggests that mastery of the physical principles of the jump may promote understanding of certain biological phenomena, aspects of physical…

  7. DC-Powered Jumping Ring

    NASA Astrophysics Data System (ADS)

    Jeffery, Rondo N.; Amiri, Farhang

    2016-02-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant differences from the AC case. In particular, the ring does not fly off the core but rises a short distance and then falls back. If the ring jumps high enough, the rising and the falling motion of the ring does not follow simple vertical motion of a projectile. This indicates that there are additional forces on the ring in each part of its motion. Four possible stages of the motion of the ring with DC are identified, which result from the ring current changing directions during the jump in response to a changing magnetic flux through the moving ring.

  8. Jump conditions in transonic equilibria

    SciTech Connect

    Guazzotto, L.; Betti, R.; Jardin, S. C.

    2013-04-15

    In the present paper, the numerical calculation of transonic equilibria, first introduced with the FLOW code in Guazzotto et al.[Phys. Plasmas 11, 604 (2004)], is critically reviewed. In particular, the necessity and effect of imposing explicit jump conditions at the transonic discontinuity are investigated. It is found that 'standard' (low-{beta}, large aspect ratio) transonic equilibria satisfy the correct jump condition with very good approximation even if the jump condition is not explicitly imposed. On the other hand, it is also found that high-{beta}, low aspect ratio equilibria require the correct jump condition to be explicitly imposed. Various numerical approaches are described to modify FLOW to include the jump condition. It is proved that the new methods converge to the correct solution even in extreme cases of very large {beta}, while they agree with the results obtained with the old implementation of FLOW in lower-{beta} equilibria.

  9. Optimizing the Distribution of Leg Muscles for Vertical Jumping

    PubMed Central

    Wong, Jeremy D.; Bobbert, Maarten F.; van Soest, Arthur J.; Gribble, Paul L.; Kistemaker, Dinant A.

    2016-01-01

    A goal of biomechanics and motor control is to understand the design of the human musculoskeletal system. Here we investigated human functional morphology by making predictions about the muscle volume distribution that is optimal for a specific motor task. We examined a well-studied and relatively simple human movement, vertical jumping. We investigated how high a human could jump if muscle volume were optimized for jumping, and determined how the optimal parameters improve performance. We used a four-link inverted pendulum model of human vertical jumping actuated by Hill-type muscles, that well-approximates skilled human performance. We optimized muscle volume by allowing the cross-sectional area and muscle fiber optimum length to be changed for each muscle, while maintaining constant total muscle volume. We observed, perhaps surprisingly, that the reference model, based on human anthropometric data, is relatively good for vertical jumping; it achieves 90% of the jump height predicted by a model with muscles designed specifically for jumping. Alteration of cross-sectional areas—which determine the maximum force deliverable by the muscles—constitutes the majority of improvement to jump height. The optimal distribution results in large vastus, gastrocnemius and hamstrings muscles that deliver more work, while producing a kinematic pattern essentially identical to the reference model. Work output is increased by removing muscle from rectus femoris, which cannot do work on the skeleton given its moment arm at the hip and the joint excursions during push-off. The gluteus composes a disproportionate amount of muscle volume and jump height is improved by moving it to other muscles. This approach represents a way to test hypotheses about optimal human functional morphology. Future studies may extend this approach to address other morphological questions in ethological tasks such as locomotion, and feature other sets of parameters such as properties of the skeletal

  10. Optimizing the Distribution of Leg Muscles for Vertical Jumping.

    PubMed

    Wong, Jeremy D; Bobbert, Maarten F; van Soest, Arthur J; Gribble, Paul L; Kistemaker, Dinant A

    2016-01-01

    A goal of biomechanics and motor control is to understand the design of the human musculoskeletal system. Here we investigated human functional morphology by making predictions about the muscle volume distribution that is optimal for a specific motor task. We examined a well-studied and relatively simple human movement, vertical jumping. We investigated how high a human could jump if muscle volume were optimized for jumping, and determined how the optimal parameters improve performance. We used a four-link inverted pendulum model of human vertical jumping actuated by Hill-type muscles, that well-approximates skilled human performance. We optimized muscle volume by allowing the cross-sectional area and muscle fiber optimum length to be changed for each muscle, while maintaining constant total muscle volume. We observed, perhaps surprisingly, that the reference model, based on human anthropometric data, is relatively good for vertical jumping; it achieves 90% of the jump height predicted by a model with muscles designed specifically for jumping. Alteration of cross-sectional areas-which determine the maximum force deliverable by the muscles-constitutes the majority of improvement to jump height. The optimal distribution results in large vastus, gastrocnemius and hamstrings muscles that deliver more work, while producing a kinematic pattern essentially identical to the reference model. Work output is increased by removing muscle from rectus femoris, which cannot do work on the skeleton given its moment arm at the hip and the joint excursions during push-off. The gluteus composes a disproportionate amount of muscle volume and jump height is improved by moving it to other muscles. This approach represents a way to test hypotheses about optimal human functional morphology. Future studies may extend this approach to address other morphological questions in ethological tasks such as locomotion, and feature other sets of parameters such as properties of the skeletal

  11. The circular internal hydraulic jump

    NASA Astrophysics Data System (ADS)

    Thorpe, S. A.; Kavcic, I.

    Circular hydraulic jumps are familiar in single layers. Here we report the discovery of similar jumps in two-layer flows. A thin jet of fluid impinging vertically onto a rigid horizontal plane surface submerged in a deep layer of less-dense miscible fluid spreads radially, and a near-circular internal jump forms within a few centimetres from the point of impact with the plane surface. A jump is similarly formed as a jet of relatively less-dense fluid rises to the surface of a deep layer of fluid, but it appears less stable or permanent in form. Several experiments are made to examine the case of a downward jet onto a horizontal plate, the base of a square or circular container. The inlet Reynolds numbers, Re, of the jet range from 112 to 1790. Initially jumps have an undular, laminar form with typically 2-4 stationary waves on the interface between the dense and less-dense layers but, as the depth of the dense layer beyond the jump increases, the transitions become more abrupt and turbulent, resulting in mixing between the two layers. During the transition to a turbulent regime, single and sometimes moving multiple cusps are observed around the periphery of jumps. A semi-empirical model is devised that relates the parameters of the laboratory experiment, i.e. flow rate, inlet nozzle radius, kinematic viscosity and reduced gravity, to the layer depth beyond the jump and the radius at which an undular jump occurs. The experiments imply that surface tension is not an essential ingredient in the formation of circular hydraulic jumps and demonstrate that stationary jumps can exist in stratified shear flows which can be represented as two discrete layers. No stationary circular undular jumps are found, however, in the case of a downward jet of dense fluid when the overlying, less-dense, fluid is stratified, but a stationary turbulent transition is observed. This has implications for the existence of stationary jumps in continuously stratified geophysical flows: results

  12. LIII subshell absorption jump ratio and jump factor of tantalum

    NASA Astrophysics Data System (ADS)

    Cengiz, Erhan; Dogan, Muhammet; Koksal, Oguz Kagan

    2013-04-01

    The LIII subshell absorption jump ratio and jump factor of tantalum have been calculated for the first time by the mass attenuation coefficients determined using narrow transmission geometry, primary source (241Am annular radioisotope source) and secondary source targets (Ni, Cu, Zn, Ga, As, Tb, Ho, Er, Tm, Yb, Cu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi). The obtained results have been compared with theoretical values. They are in good agreement with each other.

  13. Perform kicking with or without jumping: joint coordination and kinetic differences between Taekwondo back kicks and jumping back kicks.

    PubMed

    Cheng, Kuangyou B; Wang, Ying-Hsun; Kuo, Shih-Yu; Wang, Kuan-Mao; Huang, Yi-Chang

    2015-01-01

    We investigated joint coordination differences between Taekwondo back kicks and jumping back kicks, and how jumping (in performing the latter) would alter engaging ground reaction forces (GRF) in executing kicking. Ten skilful athletes volunteered to perform both kinds of kicking within the shortest time for three successful trials. Three high-speed cameras and two force platforms were used for data collection, and the trial with the shortest execution time was selected for analysis. Movements were divided into the rotation and attack phases. With comparable execution time and maximum joint linear/angular speeds, back kicks and jumping back kicks differ mainly in larger GRF in the latter, and in greater target acceleration in the former probably because the support leg prevented athletes' rebounding after impact. In addition, more prominent antiphase and in-phase coordination between the shoulder segment and knee joint, and elongated rotation phase were found in jumping back kicks. Larger GRF values in jumping back kicks were generated for jump take-off rather than for a more powerful attack. In back kicks although the support leg remained ground contact, greatly decreased GRF in the attack phase suggested that the support leg mainly served as a rotation axis. PMID:25599144

  14. Trisomy 8 with a jumping addition in ANLL

    SciTech Connect

    Berger, C.S.; Bull, R.M.; Barr, L.

    1994-09-01

    We describe a case of ANLL with an unusual cytogenetic finding. The patient is a 73-year-old male whose bone marrow showed 100% blasts. Immunophenotyping by flow cytometry found the cells to be positive for CD15, CD33, CD34, CD38, and HLA-DR. All metaphases analyzed had trisomy 8 and an identical large amount of unidentified chromosomal material incorporated at the telomere of one of three chromosomes: 47,XY,add(20)(q13.3)[15]/47,XY,add(12)(q24.3)[3]/47,XY,add(3)(p26)[2]. This may be a jumping addition, a variation of a jumping translocation with an unknown donor, or maybe an HSR with variable sites of integration. FISH results are presented to attempt to answer the question.

  15. Light-Dependent Translocation of Arrestin in Rod Photoreceptors is Signaled Through a Phospholipase C Cascade and Requires ATP

    PubMed Central

    Orisme, Wilda; Li, Jian; Goldmann, Tobias; Bolch, Susan; Wolfrum, Uwe; Smith, W. Clay

    2009-01-01

    Partitioning of cellular components is a critical mechanism by which cells can regulate their activity. In rod photoreceptors, light induces a large-scale translocation of arrestin from the inner segments to the outer segments. The purpose of this project is to elucidate the signaling pathway necessary to initiate arrestin translocation to the outer segments and the mechanism for arrestin translocation. Mouse retinal organotypic cultures and eyes from transgenic Xenopus tadpoles expressing a fusion of GFP and rod arrestin were treated with both activators and inhibitors of proteins in the phosphoinositide pathway. Confocal microscopy was used to image the effects of the pharmacological agents on arrestin translocation in rod photoreceptors. Retinas were also depleted of ATP using potassium cyanide to assess the requirement for ATP in arrestin translocation. In this study, we demonstrate that components of the G-protein-linked phospholipase C (PLC) pathway play a role in initiating arrestin translocation. Our results show that arrestin translocation can be stimulated by activators of PLC and protein kinase C (PKC), and by cholera toxin in the absence of light. Arrestin translocation to the outer segments is significantly reduced by inhibitors of PLC and PKC. Importantly, we find that treatment with potassium cyanide inhibits arrestin translocation in response to light. Collectively, our results suggest that arrestin translocation is initiated by a G-protein-coupled cascade through PLC and PKC signaling. Furthermore, our results demonstrate that at least the initiation of arrestin translocation requires energy input. PMID:19887106

  16. Optimal control simulations reveal mechanisms by which arm movement improves standing long jump performance.

    PubMed

    Ashby, Blake M; Delp, Scott L

    2006-01-01

    Optimal control simulations of the standing long jump were developed to gain insight into the mechanisms of enhanced performance due to arm motion. The activations that maximize standing long jump distance of a joint torque actuated model were determined for jumps with free and restricted arm movement. The simulated jump distance was 40 cm greater when arm movement was free (2.00 m) than when it was restricted (1.60 m). The majority of the performance improvement in the free arm jump was due to the 15% increase (3.30 vs. 2.86 m/s) in the take-off velocity of the center of gravity. Some of the performance improvement in the free arm jump was attributable to the ability of the jumper to swing the arms backwards during the flight phase to alleviate excessive forward rotation and position the body segments properly for landing. In restricted arm jumps, the excessive forward rotation was avoided by "holding back" during the propulsive phase and reducing the activation levels of the ankle, knee, and hip joint torque actuators. In addition, swinging the arm segments allowed the lower body joint torque actuators to perform 26 J more work in the free arm jump. However, the most significant contribution to developing greater take-off velocity came from the additional 80 J work done by the shoulder actuator in the jump with free arm movement. PMID:15992805

  17. Translocation of reptating chains

    NASA Astrophysics Data System (ADS)

    Żurek, S.; Drzewiński, A.; van Leeuwen, J. M. J.

    2011-05-01

    Voltage-driven translocation is modeled with the Rubinstein-Duke rules for hopping reptons in one- and two-dimensional lattices. The chain is driven through the pore by a bias potential promoting the transition of stored length in one direction. Coupling states give a semi-periodicity of the process that enables us to relate the properties to the stationary state of the master equation. The exact solution for short chains and Monte Carlo simulations for longer chains are used to calculate displacements, velocities and the translocation time.

  18. Problem-Elephant Translocation: Translocating the Problem and the Elephant?

    PubMed Central

    Fernando, Prithiviraj; Leimgruber, Peter; Prasad, Tharaka; Pastorini, Jennifer

    2012-01-01

    Human-elephant conflict (HEC) threatens the survival of endangered Asian elephants (Elephas maximus). Translocating “problem-elephants” is an important HEC mitigation and elephant conservation strategy across elephant range, with hundreds translocated annually. In the first comprehensive assessment of elephant translocation, we monitored 16 translocations in Sri Lanka with GPS collars. All translocated elephants were released into national parks. Two were killed within the parks where they were released, while all the others left those parks. Translocated elephants showed variable responses: “homers” returned to the capture site, “wanderers” ranged widely, and “settlers” established home ranges in new areas soon after release. Translocation caused wider propagation and intensification of HEC, and increased elephant mortality. We conclude that translocation defeats both HEC mitigation and elephant conservation goals. PMID:23236404

  19. Hydraulic jumps with upstream shear

    NASA Astrophysics Data System (ADS)

    Ogden, Kelly; Helfrich, Karl

    2013-11-01

    Hydraulic jumps in flows with background shear are investigated, motivated by applications such as the flow over sills in Knight Inlet and the Pre-Bosphorus Channel. The full solution space and allowable solutions to several two-layer theories for hydraulic jumps with upstream shear are identified. The two-layer theories considered, including a recent theory by Borden et al. (JFM, 2012), are distinguished by how dissipation is partitioned between the layers. It is found that upstream shear with a faster and thinner lower layer causes an increase in bore speed, for a given jump height. Further, these two-layer solutions only exist for a limited range of upstream shear. 2D numerical simulations are conducted, guided by the two-layer theory solution space, and the results are compared to the theories. The simulations show the qualitative types of hydraulic transitions that occur, including undular bores, fully turbulent jumps, and conjugate state-like solutions; the type depends on the jump height and upstream shear for fixed upstream layer depths. Numerical simulations are used to investigate the mixing. Finally, a few 3D numerical simulations were made and are found to be consistent with the 2D results.

  20. Oncogene Translocations and NHL

    Cancer.gov

    A colloboration with several large population-based cohorts to determine whether the prevalence or level of t14;18 is associated with risk of NHL and to investigate the clonal relationship between translocation-bearing cells and subsequent tumors

  1. The Jumps: Contemporary Theory, Technique and Training.

    ERIC Educational Resources Information Center

    Wilt, Fred, Ed.

    This collection of essays offers a cross section of modern theory and progress in the training of the four "jumping" events in track and field athletics--pole vault, high jump, long jump, and triple jump. It is written for athletic coaches in these specialties. Articles range from general and historical reviews of technique and training matters to…

  2. Revival of the Jumping Disc

    ERIC Educational Resources Information Center

    Ucke, C.; Schlichting, H-J.

    2009-01-01

    Snap discs made of bimetal have many technical applications as thermostats. Jumping discs are a toy version of such snap discs. Besides giving technical information, we describe physical investigations. We show especially how, through simple measurements and calculations, you can determine the initial speed ([approximately equal to]3.5 m…

  3. The Effect of Depth Jumps and Weight Training on Leg Strength and Vertical Jump.

    ERIC Educational Resources Information Center

    Clutch, David; And Others

    1983-01-01

    Two experiments examined the results of depth jumping programs to determine: (1) whether certain depth jumping routines, when combined with weight training, are better than others; and (2) the effect of depth jumping on athletes already in training. Results indicated that depth jumping is effective, but no more so than regular jumping routines.…

  4. Mesopause jumps at Antarctic latitudes

    NASA Astrophysics Data System (ADS)

    Lübken, Franz-Josef; Höffner, Josef; Becker, Erich; Latteck, Ralph; Murphy, Damian

    2016-04-01

    Recent high resolution temperature measurements by resonance lidar at Davis (69°S) occasionally showed a sudden mesopause altitude increase by ˜5 km and an associated mesopause temperature decrease by ˜10 K. We present further observations which are closely related to this 'mesopause jump', namely the increase of mean height of polar mesospheric summer echoes (PMSE) observed by a VHF radar, very strong westward winds in the upper mesosphere measured by an MF radar, and relatively large eastward winds in the stratosphere taken from reanalysis. We compare to similar observations in the Northern Hemisphere, namely at ALOMAR (69°N) where such mesopause jumps have never been observed. We present a detailed explanation of mesopause jumps. They occur only when stratospheric winds are moderately eastward and mesospheric winds are very large (westward). Under these conditions, gravity waves with comparatively large eastward phase Speeds can pass the stratosphere and propagate to the lower thermosphere because their vertical wavelengths in the mesosphere are rather large which implies reduced dynamical stability. When finally breaking in the lower thermosphere, these waves drive an enhanced residual circulation that causes a cold and high-altitude mesopause. The conditions for a mesopause jump occur only in the Southern Hemisphere (SH) and are associated with the late breakdown of the polar vortex. Mesopause jumps are primarily, but not only, observed prior and close to solstice. We also show that during the onset of PMSE in the SH, stratospheric zonal winds are still eastward (up to 30 m/s), and that the onset is not closely related to the Transition of the stratospheric circulation.

  5. Test-retest reliability of jump execution variables using mechanography: A comparison of jump protocols

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mechanography during the vertical jump test allows for evaluation of force-time variables reflecting jump execution, which may enhance screening for functional deficits that reduce physical performance and determining mechanistic causes underlying performance changes. However, utility of jump mechan...

  6. International Toys in Space: Jump Rope

    NASA Video Gallery

    Cosmonaut Valery Korzun attempts jumping rope in microgravity. He decides to adapt the activity by taking out the "jumping part," but the act of spinning the rope around him still proves difficult....

  7. Strawberry Shortcake and Other Jumping Rope Ideas.

    ERIC Educational Resources Information Center

    Adams, Polly K.; Taylor, Michaell K.

    Information, guidelines, and activities for jumping rope are given. A short history of jumping rope explains how it evolved from a spring ritual for men to a play activity involving mostly young girls. Physical and cultural reasons are given as to why jumping rope has been more a sport for girls than for boys. Research studies are noted which show…

  8. The Physics of Equestrian Show Jumping

    ERIC Educational Resources Information Center

    Stinner, Art

    2014-01-01

    This article discusses the kinematics and dynamics of equestrian show jumping. For some time I have attended a series of show jumping events at Spruce Meadows, an international equestrian center near Calgary, Alberta, often referred to as the "Wimbledon of equestrian jumping." I have always had a desire to write an article such as this…

  9. Vertical jumping and signaled avoidance

    PubMed Central

    Cándido, Antonio; Maldonado, Antonio; Vila, Jaime

    1988-01-01

    This paper reports an experiment intended to demonstrate that the vertical jumping response can be learned using a signaled-avoidance technique. A photoelectric cell system was used to record the response. Twenty female rats, divided equally into two groups, were exposed to intertrial intervals of either 15 or 40 s. Subjects had to achieve three successive criteria of acquisition: 3, 5, and 10 consecutive avoidance responses. Results showed that both groups learned the avoidance response, requiring increasingly larger numbers of trials as the acquisition criteria increased. No significant effect of intertrial interval was observed. PMID:16812559

  10. Covariant jump conditions in electromagnetism

    NASA Astrophysics Data System (ADS)

    Itin, Yakov

    2012-02-01

    A generally covariant four-dimensional representation of Maxwell's electrodynamics in a generic material medium can be achieved straightforwardly in the metric-free formulation of electromagnetism. In this setup, the electromagnetic phenomena are described by two tensor fields, which satisfy Maxwell's equations. A generic tensorial constitutive relation between these fields is an independent ingredient of the theory. By use of different constitutive relations (local and non-local, linear and non-linear, etc.), a wide area of applications can be covered. In the current paper, we present the jump conditions for the fields and for the energy-momentum tensor on an arbitrarily moving surface between two media. From the differential and integral Maxwell equations, we derive the covariant boundary conditions, which are independent of any metric and connection. These conditions include the covariantly defined surface current and are applicable to an arbitrarily moving smooth curved boundary surface. As an application of the presented jump formulas, we derive a Lorentzian type metric as a condition for existence of the wave front in isotropic media. This result holds for ordinary materials as well as for metamaterials with negative material constants.

  11. Segmental neurofibromatosis.

    PubMed

    Galhotra, Virat; Sheikh, Soheyl; Jindal, Sanjeev; Singla, Anshu

    2014-07-01

    Segmental neurofibromatosis is a rare disorder, characterized by neurofibromas or cafι-au-lait macules limited to one region of the body. Its occurrence on the face is extremely rare and only few cases of segmental neurofibromatosis over the face have been described so far. We present a case of segmental neurofibromatosis involving the buccal mucosa, tongue, cheek, ear, and neck on the right side of the face. PMID:25565748

  12. Quantum jumps and entropy production

    SciTech Connect

    Breuer, Heinz-Peter

    2003-09-01

    The irreversible motion of an open quantum system can be represented through an ensemble of state vectors following a stochastic dynamics with piecewise deterministic paths. It is shown that this representation leads to a natural definition of the rate of quantum entropy production. The entropy production rate is expressed in terms of the von Neumann entropy and of the numbers of quantum jumps corresponding to the various decay channels of the open system. The proof of the positivity and of the convexity of the entropy production rate is given. Monte Carlo simulations of the stochastic dynamics of a driven qubit and of a {lambda} configuration involving a dark state are performed in order to illustrate the general theory.

  13. Electrostatics of polymer translocation events in electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Buyukdagli, Sahin; Ala-Nissila, T.

    2016-07-01

    We develop an analytical theory that accounts for the image and surface charge interactions between a charged dielectric membrane and a DNA molecule translocating through the membrane. Translocation events through neutral carbon-based membranes are driven by a competition between the repulsive DNA-image-charge interactions and the attractive coupling between the DNA segments on the trans and the cis sides of the membrane. The latter effect is induced by the reduction of the coupling by the dielectric membrane. In strong salt solutions where the repulsive image-charge effects dominate the attractive trans-cis coupling, the DNA molecule encounters a translocation barrier of ≈10 kBT. In dilute electrolytes, the trans-cis coupling takes over image-charge forces and the membrane becomes a metastable attraction point that can trap translocating polymers over long time intervals. This mechanism can be used in translocation experiments in order to control DNA motion by tuning the salt concentration of the solution.

  14. Electrostatics of polymer translocation events in electrolyte solutions.

    PubMed

    Buyukdagli, Sahin; Ala-Nissila, T

    2016-07-01

    We develop an analytical theory that accounts for the image and surface charge interactions between a charged dielectric membrane and a DNA molecule translocating through the membrane. Translocation events through neutral carbon-based membranes are driven by a competition between the repulsive DNA-image-charge interactions and the attractive coupling between the DNA segments on the trans and the cis sides of the membrane. The latter effect is induced by the reduction of the coupling by the dielectric membrane. In strong salt solutions where the repulsive image-charge effects dominate the attractive trans-cis coupling, the DNA molecule encounters a translocation barrier of ≈10 kBT. In dilute electrolytes, the trans-cis coupling takes over image-charge forces and the membrane becomes a metastable attraction point that can trap translocating polymers over long time intervals. This mechanism can be used in translocation experiments in order to control DNA motion by tuning the salt concentration of the solution. PMID:27394120

  15. Genomic Comparison of Translocating and Non-Translocating Escherichia coli

    PubMed Central

    Bachmann, Nathan L.; Katouli, Mohammad; Polkinghorne, Adam

    2015-01-01

    Translocation of E. coli across the gut epithelium can result in fatal sepsis in post-surgical patients. In vitro and in vivo experiments have identified the existence of a novel pathotype of translocating E. coli (TEC) that employs an unknown mechanism for translocating across epithelial cells to the mesenteric lymph nodes and the blood stream in both humans and animal models. In this study the genomes of four TEC strains isolated from the mesenteric lymph nodes of a fatal case of hospitalised patient (HMLN-1), blood of pigs after experimental shock (PC-1) and after non-lethal haemorrhage in rats (KIC-1 and KIC-2) were sequenced in order to identify the genes associated with their adhesion and/or translocation. To facilitate the comparison, the genomes of a non-adhering, non-translocating E. coli (46–4) and adhering but non-translocating E. coli (73–89) were also sequenced and compared. Whole genome comparison revealed that three (HMLN-1, PC-1 and KIC-2) of the four TEC strains carried a genomic island that encodes a Type 6 Secretion System that may contribute to adhesion of the bacteria to gut epithelial cells. The human TEC strain HMLN-1 also carried the invasion ibeA gene, which was absent in the animal TEC strains and is likely to be associated with host-specific translocation. Phylogenetic analysis revealed that the four TEC strains were distributed amongst three distinct E. coli phylogroups, which was supported by the presence of phylogroup specific fimbriae gene clusters. The genomic comparison has identified potential genes that can be targeted with knock-out experiments to further characterise the mechanisms of E. coli translocation. PMID:26317913

  16. Neuromechanical simulation of the locust jump.

    PubMed

    Cofer, D; Cymbalyuk, G; Heitler, W J; Edwards, D H

    2010-04-01

    The neural circuitry and biomechanics of kicking in locusts have been studied to understand their roles in the control of both kicking and jumping. It has been hypothesized that the same neural circuit and biomechanics governed both behaviors but this hypothesis was not testable with current technology. We built a neuromechanical model to test this and to gain a better understanding of the role of the semi-lunar process (SLP) in jump dynamics. The jumping and kicking behaviors of the model were tested by comparing them with a variety of published data, and were found to reproduce the results from live animals. This confirmed that the kick neural circuitry can produce the jump behavior. The SLP is a set of highly sclerotized bands of cuticle that can be bent to store energy for use during kicking and jumping. It has not been possible to directly test the effects of the SLP on jump performance because it is an integral part of the joint, and attempts to remove its influence prevent the locust from being able to jump. Simulations demonstrated that the SLP can significantly increase jump distance, power, total energy and duration of the jump impulse. In addition, the geometry of the joint enables the SLP force to assist leg flexion when the leg is flexed, and to assist extension once the leg has begun to extend. PMID:20228342

  17. Effects of spine flexion and erector spinae maximal force on vertical squat jump height: a computational simulation study.

    PubMed

    Blache, Yoann; Monteil, Karine

    2015-03-01

    The purpose of this study was to evaluate the single and combined effects of initial spine flexion and maximal isometric force of the erector spinae on maximal vertical jump height during maximal squat jumping. Seven initial flexions of the 'thorax-head-arm' segment (between 20.1° and 71.6°) and five maximal isometric forces of the erector spinae (between 5600 and 8600 N) were tested. Thus, 35 squat jumps were simulated using a 2D simulation model of the musculoskeletal system. Vertical jump height varied at most about 0.094 and 0.021 m when the initial flexion of the 'thorax-head-arm' segment and the maximal force of the erector spinae were, respectively, maximal. These results were explained for the most part by the variation of total muscle work. The latter was mainly influenced by the work produced by the erector spinae which increased at most about 57 and 110 J when the initial flexion of the 'thorax-head-arm' segment and the maximal force of the erector spinae were, respectively, maximal. It was concluded that the increase in the initial flexion of the 'thorax-head-arm' segment and in the maximal isometric force of the erector spinae enables an increase in maximal vertical jump height during maximal squat jumping. PMID:25895521

  18. A power function profile of a ski jumping in-run hill.

    PubMed

    Zanevskyy, Ihor

    2011-01-01

    The aim of the research was to find a function of the curvilinear segment profile which could make possible to avoid an instantaneous increasing of a curvature and to replace a circle arc segment on the in-run of a ski jump without any correction of the angles of inclination and the length of the straight-line segments. The methods of analytical geometry and trigonometry were used to calculate an optimal in-run hill profile. There were two fundamental conditions of the model: smooth borders between a curvilinear segment and straight-line segments of an in-run hill and concave of the curvilinear segment. Within the framework of this model, the problem has been solved with a reasonable precision. Four functions of a curvilinear segment profile of the in-run hill were investigated: circle arc, inclined quadratic parabola, inclined cubic parabola, and power function. The application of a power function to the in-run profile satisfies equal conditions for replacing a circle arc segment. Geometrical parameters of 38 modern ski jumps were investigated using the methods proposed. PMID:22339056

  19. Production and Identification of Wheat-Agropyron cristatum 2P Translocation Lines.

    PubMed

    Li, Huanhuan; Lv, Mingjie; Song, Liqiang; Zhang, Jinpeng; Gao, Ainong; Li, Lihui; Liu, Weihua

    2016-01-01

    Agropyron cristatum (L.) Gaertn. (2n = 28, PPPP), a wild relative of common wheat, possesses many potentially valuable traits that can be transferred to common wheat through breeding programs. The wheat-A. cristatum disomic addition and translocation lines can be used as bridge materials to introduce alien chromosomal segments to wheat. Wheat-A. cristatum 2P disomic addition line II-9-3 was highly resistant to powdery mildew and leaf rust, which was reported in our previous study. However, some translocation lines induced from II-9-3 have not been reported. In this study, some translocation lines were induced from II-9-3 by 60Co-γ irradiation and gametocidal chromosome 2C and then identified by cytological methods. Forty-nine wheat-A. cristatum translocation lines were obtained and various translcoation types were identified by GISH (genomic in situ hybridization), such as whole-arm, segmental and intercalary translocations. Dual-color FISH (fluorescent in situ hybridization) was applied to identify the wheat chromosomes involved in the translocations, and the results showed that A. cristatum 2P chromosome segments were translocated to the different wheat chromosomes, including 1A, 2A, 3A, 4A, 5A, 6A, 7A, 3B, 5B, 7B, 1D, 4D and 6D. Many different types of wheat-A. cristatum alien translocation lines would be valuable for not only identifying and cloning A. cristatum 2P-related genes and understanding the genetics and breeding effects of the translocation between A. cristatum chromosome 2P and wheat chromosomes, but also providing new germplasm resources for the wheat genetic improvement. PMID:26731742

  20. Production and Identification of Wheat-Agropyron cristatum 2P Translocation Lines

    PubMed Central

    Li, Huanhuan; Lv, Mingjie; Song, Liqiang; Zhang, Jinpeng; Gao, Ainong; Li, Lihui; Liu, Weihua

    2016-01-01

    Agropyron cristatum (L.) Gaertn. (2n = 28, PPPP), a wild relative of common wheat, possesses many potentially valuable traits that can be transferred to common wheat through breeding programs. The wheat-A. cristatum disomic addition and translocation lines can be used as bridge materials to introduce alien chromosomal segments to wheat. Wheat-A. cristatum 2P disomic addition line II-9-3 was highly resistant to powdery mildew and leaf rust, which was reported in our previous study. However, some translocation lines induced from II-9-3 have not been reported. In this study, some translocation lines were induced from II-9-3 by 60Co-γ irradiation and gametocidal chromosome 2C and then identified by cytological methods. Forty-nine wheat-A. cristatum translocation lines were obtained and various translcoation types were identified by GISH (genomic in situ hybridization), such as whole-arm, segmental and intercalary translocations. Dual-color FISH (fluorescent in situ hybridization) was applied to identify the wheat chromosomes involved in the translocations, and the results showed that A. cristatum 2P chromosome segments were translocated to the different wheat chromosomes, including 1A, 2A, 3A, 4A, 5A, 6A, 7A, 3B, 5B, 7B, 1D, 4D and 6D. Many different types of wheat-A. cristatum alien translocation lines would be valuable for not only identifying and cloning A. cristatum 2P-related genes and understanding the genetics and breeding effects of the translocation between A. cristatum chromosome 2P and wheat chromosomes, but also providing new germplasm resources for the wheat genetic improvement. PMID:26731742

  1. Segmental neurofibromatosis.

    PubMed

    Toy, Brian

    2003-10-01

    Segmental neurofibromatosis is a rare variant of neurofibromatosis in which skin lesions are confined to a circumscribed body segment. A case of a 72-year-old woman with this condition is presented. Clinical features and genetic evidence are reviewed. PMID:14594599

  2. Active Segmentation

    PubMed Central

    Mishra, Ajay; Aloimonos, Yiannis

    2009-01-01

    The human visual system observes and understands a scene/image by making a series of fixations. Every fixation point lies inside a particular region of arbitrary shape and size in the scene which can either be an object or just a part of it. We define as a basic segmentation problem the task of segmenting that region containing the fixation point. Segmenting the region containing the fixation is equivalent to finding the enclosing contour- a connected set of boundary edge fragments in the edge map of the scene - around the fixation. This enclosing contour should be a depth boundary. We present here a novel algorithm that finds this bounding contour and achieves the segmentation of one object, given the fixation. The proposed segmentation framework combines monocular cues (color/intensity/texture) with stereo and/or motion, in a cue independent manner. The semantic robots of the immediate future will be able to use this algorithm to automatically find objects in any environment. The capability of automatically segmenting objects in their visual field can bring the visual processing to the next level. Our approach is different from current approaches. While existing work attempts to segment the whole scene at once into many areas, we segment only one image region, specifically the one containing the fixation point. Experiments with real imagery collected by our active robot and from the known databases 1 demonstrate the promise of the approach. PMID:20686671

  3. Abdominal radiation causes bacterial translocation

    SciTech Connect

    Guzman-Stein, G.; Bonsack, M.; Liberty, J.; Delaney, J.P.

    1989-02-01

    The purpose of this study was to determine if a single dose of radiation to the rat abdomen leads to bacterial translocation into the mesenteric lymph nodes (MLN). A second issue addressed was whether translocation correlates with anatomic damage to the mucosa. The radiated group (1100 cGy) which received anesthesia also was compared with a control group and a third group which received anesthesia alone but no abdominal radiation. Abdominal radiation lead to 100% positive cultures of MLN between 12 hr and 4 days postradiation. Bacterial translocation was almost nonexistent in the control and anesthesia group. Signs of inflammation and ulceration of the intestinal mucosa were not seen until Day 3 postradiation. Mucosal damage was maximal by Day 4. Bacterial translocation onto the MLN after a single dose of abdominal radiation was not apparently dependent on anatomical, histologic damage of the mucosa.

  4. Structural insights into ribosome translocation.

    PubMed

    Ling, Clarence; Ermolenko, Dmitri N

    2016-09-01

    During protein synthesis, tRNA and mRNA are translocated from the A to P to E sites of the ribosome thus enabling the ribosome to translate one codon of mRNA after the other. Ribosome translocation along mRNA is induced by the universally conserved ribosome GTPase, elongation factor G (EF-G) in bacteria and elongation factor 2 (EF-2) in eukaryotes. Recent structural and single-molecule studies revealed that tRNA and mRNA translocation within the ribosome is accompanied by cyclic forward and reverse rotations between the large and small ribosomal subunits parallel to the plane of the intersubunit interface. In addition, during ribosome translocation, the 'head' domain of small ribosomal subunit undergoes forward- and back-swiveling motions relative to the rest of the small ribosomal subunit around the axis that is orthogonal to the axis of intersubunit rotation. tRNA/mRNA translocation is also coupled to the docking of domain IV of EF-G into the A site of the small ribosomal subunit that converts the thermally driven motions of the ribosome and tRNA into the forward translocation of tRNA/mRNA inside the ribosome. Despite recent and enormous progress made in the understanding of the molecular mechanism of ribosome translocation, the sequence of structural rearrangements of the ribosome, EF-G and tRNA during translocation is still not fully established and awaits further investigation. WIREs RNA 2016, 7:620-636. doi: 10.1002/wrna.1354 For further resources related to this article, please visit the WIREs website. PMID:27117863

  5. Positive charges on the translocating polypeptide chain arrest movement through the translocon.

    PubMed

    Fujita, Hidenobu; Yamagishi, Marifu; Kida, Yuichiro; Sakaguchi, Masao

    2011-12-15

    Polypeptide chains synthesized by membrane-bound ribosomes are translocated through, and integrated into, the endoplasmic reticulum (ER) membrane by means of the protein translocation channel, the translocon. Positive charges on the nascent chain determine the orientation of the hydrophobic segment as it is inserted into the translocon and enhance the stop-translocation of translocating hydrophobic segments. Here we show that positive charges temporarily arrested ongoing polypeptide chain movement through the ER translocon by electrostatic interaction, even in the absence of a hydrophobic segment. The C-terminus of the polypeptide chain was elongated during the arrest, and then the full-length polypeptide chain moved through the translocon. The translocation-arrested polypeptide was not anchored to the membrane and the charges were on the cytoplasmic side of the membrane. The arrest effect was prevented by negatively charged residues inserted into the positive-charge cluster, and it was also suppressed by high salt conditions. We propose that positive charges are independent translocation regulators that are more active than previously believed. PMID:22223880

  6. Jumping to conclusions in schizophrenia

    PubMed Central

    Evans, Simon L; Averbeck, Bruno B; Furl, Nicholas

    2015-01-01

    Schizophrenia is a mental disorder associated with a variety of symptoms, including hallucinations, delusions, social withdrawal, and cognitive dysfunction. Impairments on decision-making tasks are routinely reported: evidence points to a particular deficit in learning from and revising behavior following feedback. In addition, patients tend to make hasty decisions when probabilistic judgments are required. This is known as “jumping to conclusions” (JTC) and has typically been demonstrated by presenting participants with colored beads drawn from one of two “urns” until they claim to be sure which urn the beads are being drawn from (the proportions of colors vary in each urn). Patients tend to make early decisions on this task, and there is evidence to suggest that a hasty decision-making style might be linked to delusion formation and thus be of clinical relevance. Various accounts have been proposed regarding what underlies this behavior. In this review, we briefly introduce the disorder and the decision-making deficits associated with it. We then explore the evidence for each account of JTC in the context of a wider decision-making deficit and then go on to summarize work exploring JTC in healthy controls using pharmacological manipulations and functional imaging. Finally, we assess whether JTC might have a role in therapy. PMID:26170674

  7. Internal hydraulic jumps with large upstream shear

    NASA Astrophysics Data System (ADS)

    Ogden, Kelly; Helfrich, Karl

    2015-11-01

    Internal hydraulic jumps in approximately two-layered flows with large upstream shear are investigated using numerical simulations. The simulations allow continuous density and velocity profiles, and a jump is forced to develop by downstream topography, similar to the experiments conducted by Wilkinson and Wood (1971). High shear jumps are found to exhibit significantly more entrainment than low shear jumps. Furthermore, the downstream structure of the flow has an important effect on the jump properties. Jumps with a slow upper (inactive) layer exhibit a velocity minimum downstream of the jump, resulting in a sub-critical downstream state, while flows with the same upstream vertical shear and a larger barotropic velocity remain super-critical downstream of the jump. A two-layer theory is modified to account for the vertical structure of the downstream density and velocity profiles and entrainment is allowed through a modification of the approach of Holland et al. (2002). The resulting theory can be matched reasonably well with the numerical simulations. However, the results are very sensitive to how the downstream vertical profiles of velocity and density are incorporated into the layered model, highlighting the difficulty of the two layer approximation when the shear is large.

  8. Natural and systematic polar motion jumps

    NASA Astrophysics Data System (ADS)

    Chapanov, Y.; Vondrak, J.; Ron, C.; Pachalieva, R.

    2014-12-01

    Polar motion consists mainly of two harmonic oscillations with variable phases and amplitudes and small irregular variations. The small irregular variations may be due to various geophysical excitations and observation inaccuracy (mostly in the first half of the last century). A part of irregular polar motion variations consists of fast jumps of the mean values of polar motion coordinates. The direct determination of the polar motion jumps is difficult, because the jump values are very small relative to the seasonal and Chandler amplitudes. A useful high sensitive method of data jumps determination is proposed. The method consists of data integration and piecewise linear or parabolic trends determina- tion. This method is applied to determine the natural and systematic polar motion jumps existing in pole coordinates from the solutions OA10 for the period 1899.7ñ1962.0 and C04 for the period 1962.0- 2013.5. Only a few of the determined polar motion jumps can be interpreted as systematic biases due to observational errors. The major part of the detected polar motion jumps occurs almost regularly near the epochs of minimum amplitude (due to the beat of seasonal and Chandler wobbles), so the natural origin of these jumps is supposed.

  9. Rope Jumping: A Preliminary Developmental Study.

    ERIC Educational Resources Information Center

    Wickstrom, Ralph L.

    The basic movement pattern used in skilled individual rope jumping performance was determined and used as a model against which to evaluate the rope jumping form used by children at various levels of skills development. The techniques of adults and nursery school children were filmed and analyzed. The specific causes of unsuccessful attempts were…

  10. The Phase Shift in the Jumping Ring

    ERIC Educational Resources Information Center

    Jeffery, Rondo N.; Amiri, Farhang

    2008-01-01

    The popular physics demonstration experiment known as Thomson's Jumping Ring (JR) has been variously explained as a simple example of Lenz's law, or as the result of a phase shift of the ring current relative to the induced emf. The failure of the first-quadrant Lenz's law explanation is shown by the time the ring takes to jump and by levitation.…

  11. The Locust Jump: An Integrated Laboratory Investigation

    ERIC Educational Resources Information Center

    Scott, Jon

    2005-01-01

    The locust is well known for its ability to jump large distances to avoid predation. This class sets out a series of investigations into the mechanisms underlying the jump enabling students to bring together information from biomechanics, muscle physiology, and anatomy. The nature of the investigation allows it to be undertaken at a number of…

  12. 25 CFR 11.437 - Bail jumping.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Bail jumping. 11.437 Section 11.437 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAW AND ORDER COURTS OF INDIAN OFFENSES AND LAW AND ORDER CODE Criminal Offenses § 11.437 Bail jumping. A person set at liberty by court order, with or without bail,...

  13. 25 CFR 11.437 - Bail jumping.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Bail jumping. 11.437 Section 11.437 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAW AND ORDER COURTS OF INDIAN OFFENSES AND LAW AND ORDER CODE Criminal Offenses § 11.437 Bail jumping. A person set at liberty by court order, with or without bail,...

  14. Control of tumbling during the locust jump

    PubMed Central

    Cofer, David; Cymbalyuk, Gennady; Heitler, William J.; Edwards, Donald H.

    2010-01-01

    Locust can jump precisely to a target, yet they can also tumble during the trajectory. We propose two mechanisms that would allow the locust to control tumbling during the jump. The first is that prior to the jump, locusts adjust the pitch of their body to move the center of mass closer to the intended thrust vector. The second is that contraction of the dorsolongitudinal muscles during the jump will produce torques that counter the torque produced by thrust. We found that locusts increased their take-off angle as the initial body pitch increased, and that little tumbling occurred for jumps that observed this relationship. Simulations of locust jumping demonstrated that a pitch versus take-off angle relationship that minimized tumbling in simulated jumps was similar to the relationship observed in live locusts. Locusts were strongly biased to pitch head-upward, and performed dorsiflexions far more often than ventral flexions. The direction and magnitude of tumbling could be controlled in simulations by adjusting the tension in the dorsolongitudinal muscles. These mechanisms allowed the simulations to match the data from the live animals. Control of tumbling was also found to influence the control of jump elevation. The bias to pitch head-upwards may have an evolutionary advantage when evading a predator and so make control of tumbling important for the locust. PMID:20833932

  15. Control of tumbling during the locust jump.

    PubMed

    Cofer, David; Cymbalyuk, Gennady; Heitler, William J; Edwards, Donald H

    2010-10-01

    Locust can jump precisely to a target, yet they can also tumble during the trajectory. We propose two mechanisms that would allow the locust to control tumbling during the jump. The first is that prior to the jump, locusts adjust the pitch of their body to move the center of mass closer to the intended thrust vector. The second is that contraction of the dorsolongitudinal muscles during the jump will produce torques that counter the torque produced by thrust. We found that locusts increased their take-off angle as the initial body pitch increased, and that little tumbling occurred for jumps that observed this relationship. Simulations of locust jumping demonstrated that a pitch versus take-off angle relationship that minimized tumbling in simulated jumps was similar to the relationship observed in live locusts. Locusts were strongly biased to pitch head-upward, and performed dorsiflexions far more often than ventral flexions. The direction and magnitude of tumbling could be controlled in simulations by adjusting the tension in the dorsolongitudinal muscles. These mechanisms allowed the simulations to match the data from the live animals. Control of tumbling was also found to influence the control of jump elevation. The bias to pitch head-upwards may have an evolutionary advantage when evading a predator and so make control of tumbling important for the locust. PMID:20833932

  16. A review on the basketball jump shot.

    PubMed

    Okazaki, Victor H A; Rodacki, André L F; Satern, Miriam N

    2015-06-01

    The ability to shoot an effective jump shot in the sport of basketball is critical to a player's success. In an attempt to better understand the aspects related to expert performance, researchers have investigated successful free throws and jump shots of various basketball players and identified movement variables that contribute to their success. The purpose of this study was to complete a systematic review of the scientific literature on the basketball free throw and jump shot for the purpose of revealing the critical components of shooting that coaches, teachers, and players should focus on when teaching, learning, practising, and performing a jump shot. The results of this review are presented in three sections: (a) variables that affect ball trajectory, (b) phases of the jump shot, and PMID:26102462

  17. Computer simulation of viral-assembly and translocation

    NASA Astrophysics Data System (ADS)

    Mahalik, Jyoti Prakash

    We investigated four different problems using coarse grained computational models : self-assembly of single stranded (ss) DNA virus, ejection dynamics of double stranded(ds) DNA from phages, translocation of ssDNA through MspA protein pore, and segmental dynamics of a polymer translocating through a synthetic nanopore. In the first part of the project, we investigated the self-assembly of a virus with and without its genome. A coarse-grained model was proposed for the viral subunit proteins and its genome (ssDNA). Langevin dynamics simulation, and replica exchange method were used to determine the kinetics and energetics of the self-assembly process, respectively. The self-assembly follows a nucleation-growth kind of mechanism. The ssDNA plays a crucial role in the self-assembly by acting as a template and enhancing the local concentration of the subunits. The presence of the genome does not changes the mechanism of the self-assembly but it reduces the nucleation time and enhances the growth rate by almost an order of magnitude. The second part of the project involves the investigation of the dynamics of the ejection of dsDNA from phages. A coarse-grained model was used for the phage and dsDNA. Langevin dynamics simulation was used to investigate the kinetics of the ejection. The ejection is a stochastic process and a slow intermediate rate kinetics was observed for most ejection trajectories. We discovered that the jamming of the DNA at the pore mouth at high packing fraction and for a disordered system is the reason for the intermediate slow kinetics. The third part of the project involves translocation of ssDNA through MspA protein pore. MspA protein pore has the potential for genome sequencing because of its ability to clearly distinguish the four different nucleotides based on their blockade current, but it is a challenge to use this pore for any practical application because of the very fast traslocation time. We resolved the state of DNA translocation

  18. Downside risk of wildlife translocation.

    PubMed

    Chipman, R; Slate, D; Rupprecht, C; Mendoza, M

    2008-01-01

    Translocation has been used successfully by wildlife professionals to enhance or reintroduce populations of rare or extirpated wildlife, provide hunting or wildlife viewing opportunities, farm wild game, and reduce local human-wildlife conflicts. However, accidental and intentional translocations may have multiple unintended negative consequences, including increased stress and mortality of relocated animals, negative impacts on resident animals at release sites, increased conflicts with human interests, and the spread of diseases. Many wildlife professionals now question the practice of translocation, particularly in light of the need to contain or eliminate high profile, economically important wildlife diseases and because using this technique may jeopardize international wildlife disease management initiatives to control rabies in raccoons, coyotes, and foxes in North America. Incidents have been documented where specific rabies variants (Texas gray fox, canine variant in coyotes, and raccoon) have been moved well beyond their current range as a result of translocation, including the emergence of raccoon rabies in the eastern United States. Here, we review and discuss the substantial challenges of curtailing translocation in the USA, focusing on movement of animals by the public, nuisance wildlife control operators, and wildlife rehabilitators. PMID:18634483

  19. Biomechanics of jumping in the flea.

    PubMed

    Sutton, Gregory P; Burrows, Malcolm

    2011-03-01

    It has long been established that fleas jump by storing and releasing energy in a cuticular spring, but it is not known how forces from that spring are transmitted to the ground. One hypothesis is that the recoil of the spring pushes the trochanter onto the ground, thereby generating the jump. A second hypothesis is that the recoil of the spring acts through a lever system to push the tibia and tarsus onto the ground. To decide which of these two hypotheses is correct, we built a kinetic model to simulate the different possible velocities and accelerations produced by each proposed process and compared those simulations with the kinematics measured from high-speed images of natural jumping. The in vivo velocity and acceleration kinematics are consistent with the model that directs ground forces through the tibia and tarsus. Moreover, in some natural jumps there was no contact between the trochanter and the ground. There were also no observable differences between the kinematics of jumps that began with the trochanter on the ground and jumps that did not. Scanning electron microscopy showed that the tibia and tarsus have spines appropriate for applying forces to the ground, whereas no such structures were seen on the trochanter. Based on these observations, we discount the hypothesis that fleas use their trochantera to apply forces to the ground and conclude that fleas jump by applying forces to the ground through the end of the tibiae. PMID:21307071

  20. Kinematics and Kinetics of Squats, Drop Jumps and Imitation Jumps of Ski Jumpers

    PubMed Central

    Pauli, Carole A.; Keller, Melanie; Ammann, Fabian; Hübner, Klaus; Lindorfer, Julia; Taylor, William R.

    2016-01-01

    Abstract Pauli, CA, Keller, M, Ammann, F, Hübner, K, Lindorfer, J, Taylor, WR, and Lorenzetti, S. Kinematics and kinetics of squats, drop jumps and imitation jumps of ski jumpers. J Strength Cond Res 30(3): 643–652, 2016—Squats, drop jumps, and imitation jumps are commonly used training exercises in ski jumping to enhance maximum force, explosive force, and sport-specific skills. The purpose of this study was to evaluate the kinetics and kinematics of training exercises in ski jumping and to find objective parameters in training exercises that most correlate with the competition performance of ski jumpers. To this end, barbell squats, drop jumps, and imitation jumps were measured in a laboratory environment for 10 elite ski jumpers. Force and motion data were captured, and the influence of maximum vertical force, force difference, vertical take-off velocity, knee moments, knee joint power, and a knee valgus/varus index was evaluated and correlated with their season jump performance. The results indicate that, especially for the imitation jumps, a good correlation exists between the vertical take-off velocity and the personal jump performance on the hill (R = 0.718). Importantly, however, the more the athletes tended toward a valgus knee alignment during the measured movements, the worse their performance (R = 0.729 imitation jumps; R = 0.685 squats). Although an evaluation of the athletes' lower limb alignment during competitive jumping on the hill is still required, these preliminary data suggest that performance training should additionally concentrate on improving knee alignment to increase ski jumping performance. PMID:26418370

  1. Predicting vertical jump height from bar velocity.

    PubMed

    García-Ramos, Amador; Štirn, Igor; Padial, Paulino; Argüelles-Cienfuegos, Javier; De la Fuente, Blanca; Strojnik, Vojko; Feriche, Belén

    2015-06-01

    The objective of the study was to assess the use of maximum (Vmax) and final propulsive phase (FPV) bar velocity to predict jump height in the weighted jump squat. FPV was defined as the velocity reached just before bar acceleration was lower than gravity (-9.81 m·s(-2)). Vertical jump height was calculated from the take-off velocity (Vtake-off) provided by a force platform. Thirty swimmers belonging to the National Slovenian swimming team performed a jump squat incremental loading test, lifting 25%, 50%, 75% and 100% of body weight in a Smith machine. Jump performance was simultaneously monitored using an AMTI portable force platform and a linear velocity transducer attached to the barbell. Simple linear regression was used to estimate jump height from the Vmax and FPV recorded by the linear velocity transducer. Vmax (y = 16.577x - 16.384) was able to explain 93% of jump height variance with a standard error of the estimate of 1.47 cm. FPV (y = 12.828x - 6.504) was able to explain 91% of jump height variance with a standard error of the estimate of 1.66 cm. Despite that both variables resulted to be good predictors, heteroscedasticity in the differences between FPV and Vtake-off was observed (r(2) = 0.307), while the differences between Vmax and Vtake-off were homogenously distributed (r(2) = 0.071). These results suggest that Vmax is a valid tool for estimating vertical jump height in a loaded jump squat test performed in a Smith machine. Key pointsVertical jump height in the loaded jump squat can be estimated with acceptable precision from the maximum bar velocity recorded by a linear velocity transducer.The relationship between the point at which bar acceleration is less than -9.81 m·s(-2) and the real take-off is affected by the velocity of movement.Mean propulsive velocity recorded by a linear velocity transducer does not appear to be optimal to monitor ballistic exercise performance. PMID:25983572

  2. Condensation-induced jumping water drops

    NASA Astrophysics Data System (ADS)

    Narhe, R. D.; Khandkar, M. D.; Shelke, P. B.; Limaye, A. V.; Beysens, D. A.

    2009-09-01

    Water droplets can jump during vapor condensation on solid benzene near its melting point. This phenomenon, which can be viewed as a kind of micro scale steam engine, is studied experimentally and numerically. The latent heat of condensation transferred at the drop three phase contact line melts the substrate during a time proportional to R (the drop radius). The wetting conditions change and a spontaneous jump of the drop results in random direction over length ˜1.5R , a phenomenon that increases the coalescence events and accelerates the growth. Once properly rescaled by the jump length scale, the growth dynamics is, however, similar to that on a solid surface.

  3. Condensation-induced jumping water drops.

    PubMed

    Narhe, R D; Khandkar, M D; Shelke, P B; Limaye, A V; Beysens, D A

    2009-09-01

    Water droplets can jump during vapor condensation on solid benzene near its melting point. This phenomenon, which can be viewed as a kind of micro scale steam engine, is studied experimentally and numerically. The latent heat of condensation transferred at the drop three phase contact line melts the substrate during a time proportional to R (the drop radius). The wetting conditions change and a spontaneous jump of the drop results in random direction over length approximately 1.5R , a phenomenon that increases the coalescence events and accelerates the growth. Once properly rescaled by the jump length scale, the growth dynamics is, however, similar to that on a solid surface. PMID:19905120

  4. Protein translocation: what's the problem?

    PubMed Central

    Corey, Robin A.; Allen, William J.; Collinson, Ian

    2016-01-01

    We came together in Leeds to commemorate and celebrate the life and achievements of Prof. Stephen Baldwin. For many years we, together with Sheena Radford and Roman Tuma (colleagues also of the University of Leeds), have worked together on the problem of protein translocation through the essential and ubiquitous Sec system. Inspired and helped by Steve we may finally be making progress. My seminar described our latest hypothesis for the molecular mechanism of protein translocation, supported by results collected in Bristol and Leeds on the tractable bacterial secretion process–commonly known as the Sec system; work that will be published elsewhere. Below is a description of the alternative and contested models for protein translocation that we all have been contemplating for many years. This review will consider their pros and cons. PMID:27284038

  5. Protein translocation: what's the problem?

    PubMed

    Corey, Robin A; Allen, William J; Collinson, Ian

    2016-06-15

    We came together in Leeds to commemorate and celebrate the life and achievements of Prof. Stephen Baldwin. For many years we, together with Sheena Radford and Roman Tuma (colleagues also of the University of Leeds), have worked together on the problem of protein translocation through the essential and ubiquitous Sec system. Inspired and helped by Steve we may finally be making progress. My seminar described our latest hypothesis for the molecular mechanism of protein translocation, supported by results collected in Bristol and Leeds on the tractable bacterial secretion process-commonly known as the Sec system; work that will be published elsewhere. Below is a description of the alternative and contested models for protein translocation that we all have been contemplating for many years. This review will consider their pros and cons. PMID:27284038

  6. The mechanics of ribosomal translocation.

    PubMed

    Achenbach, John; Nierhaus, Knud H

    2015-07-01

    The ribosome translates the sequence of codons of an mRNA into the corresponding sequence of amino acids as it moves along the mRNA with a codon-step width of about 10 Å. The movement of the million-dalton complex ribosome is triggered by the universal elongation factor G (EF2 in archaea and eukaryotes) and is termed translocation. Unraveling the molecular details of translocation is one of the most challenging tasks of current ribosome research. In the last two years, enormous progress has been obtained by highly-resolved X-ray and cryo-electron microscopic structures as well as by sophisticated biochemical approaches concerning the trigger and control of the movement of the tRNA2·mRNA complex inside the ribosome during translocation. This review inspects and surveys these achievements. PMID:25514765

  7. Jumping without using legs: the jump of the click-beetles (Elateridae) is morphologically constrained.

    PubMed

    Ribak, Gal; Weihs, Daniel

    2011-01-01

    To return to their feet, inverted click-beetles (Elateridae) jump without using their legs. When a beetle is resting on its dorsal side, a hinge mechanism is locked to store elastic energy in the body and releases it abruptly to launch the beetle into the air. While the functional morphology of the jumping mechanism is well known, the level of control that the beetle has over this jumping technique and the mechanical constraints governing the jumps are not entirely clear. Here we show that while body rotations in air are highly variable, the jumps are morphologically constrained to a constant "takeoff" angle (79.9°±1.56°, n = 9 beetles) that directs 98% of the jumping force vertically against gravity. A physical-mathematical model of the jumping action, combined with measurements from live beetle, imply that the beetle may control the speed at takeoff but not the jumping angle. In addition, the model shows that very subtle changes in the exact point of contact with the ground can explain the vigorous rotations of the body seen while the beetle is airborne. These findings suggest that the evolution of this unique non-legged jumping mechanism resulted in a jumping technique that is capable of launching the body high into the air but it is too constrained and unstable to allow control of body orientation at landing. PMID:21698194

  8. Partners with reciprocal translocations: genetic counseling for the 'double translocation'.

    PubMed

    Cook, L; Hartsfield, J K; Vance, G H

    1998-05-01

    SV at age 2 years presented with multiple congenital anomalies including an absent left kidney, anal stenosis, vertebral abnormalities, partial sacral agenesis, microcephaly, dysmorphic facial features, growth deficiency, and developmental delay. She was found to have a complex chromosomal rearrangement derived from balanced translocations in each parent. PMID:9660061

  9. PERFORMANCE OF THE AGS TRANSITION JUMP SYSTEM.

    SciTech Connect

    AHRENS,L.A.; BRENNAN,J.M.; GLENN,J.W.; ROSER,T.; VAN ASSELT,W.K.

    1999-03-29

    The transition jump system has been indispensable to the high intensity proton operation of the AGS complex. Nevertheless, transition crossing remains one of the major hurdles as the accelerator complex intensity is pushed upward. To enhance the performance of the system ''quadrupole pumping'' in the Booster is used to minimize the necessary longitudinal dilution of the beam on the AGS injection porch. During the transition jump sextupole correctors at strategic locations are pulsed to minimize the effects of the chromatic non-linearity of the jump system. The available instrumentation for diagnosing the performance of the system will be described, along with installed hardware to counter the non-linear effects of the transition jump system.

  10. Injuries At Indoor Trampoline Parks Jump

    MedlinePlus

    ... news/fullstory_160460.html Injuries at Indoor Trampoline Parks Jump Researchers say finding shows need for safety ... News) -- A wave of injuries at indoor trampoline parks has prompted a call for design and safety ...

  11. Segmented combustor

    NASA Technical Reports Server (NTRS)

    Halila, Ely E. (Inventor)

    1994-01-01

    A combustor liner segment includes a panel having four sidewalls forming a rectangular outer perimeter. A plurality of integral supporting lugs are disposed substantially perpendicularly to the panel and extend from respective ones of the four sidewalls. A plurality of integral bosses are disposed substantially perpendicularly to the panel and extend from respective ones of the four sidewalls, with the bosses being shorter than the lugs. In one embodiment, the lugs extend through supporting holes in an annular frame for mounting the liner segments thereto, with the bosses abutting the frame for maintaining a predetermined spacing therefrom.

  12. Pulmonary hemorrhage resulting from bungee jumping.

    PubMed

    Manos, Daria; Hamer, Okka; Müller, Nestor L

    2007-11-01

    Pulmonary hemorrhage is a relatively common complication of blunt chest trauma. Occasionally, it may result from pulmonary barotrauma after scuba diving or from sports activities not associated with barotrauma such as long breath-hold diving. We report a case of symmetric diffuse upper lobe hemorrhage resulting from a bungee jump in a previously healthy man. Bungee jumping is an increasingly popular sport with relatively few reported injuries. To our knowledge pulmonary hemorrhage in this setting has not yet been described. PMID:18043394

  13. Jumping mechanisms in dictyopharid planthoppers (Hemiptera, Dicytyopharidae).

    PubMed

    Burrows, Malcolm

    2014-02-01

    The jumping performance of four species of hemipterans belonging to the family Dictyopharidae, from Europe, South Africa and Australia, were analysed from high-speed images. The body shape in all was characterised by an elongated and tapering head that gave a streamlined appearance. The body size ranged from 6 to 9 mm in length and from 6 to 23 mg in mass. The hind legs were 80-90% of body length and 30-50% longer than the front legs, except in one species in which the front legs were particularly large so that all legs were of similar length. Jumping was propelled by rapid and simultaneous depression of the trochantera of both hind legs, powered by large muscles in the thorax, and was accompanied by extension of the tibiae. In the best jumps, defined as those with the fastest take-off velocity, Engela minuta accelerated in 1.2 ms to a take-off velocity of 5.8 m s(-1), which is the fastest achieved by any insect described to date. During such a jump, E. minuta experienced an acceleration of 4830 m s(-2) or 490 g, while other species in the same family experienced 225-375 g. The best jumps in all species required an energy expenditure of 76-225 μJ, a power output of 12-80 mW and exerted a force of 12-29 mN. The required power output per mass of jumping muscle ranged from 28,000 to 140,200 W kg(-1) muscle and thus greatly exceeded the maximum active contractile limit of normal muscle. To achieve such a jumping performance, these insects must be using a power amplification mechanism in a catapult-like action. It is suggested that their streamlined body shape improves jumping performance by reducing drag, which, for a small insect, can substantially affect forward momentum. PMID:24198256

  14. Molecular cytogenetic characterization of novel wheat-Thinopyrum bessarabicum recombinant lines carrying intercalary translocations.

    PubMed

    Patokar, Chetan; Sepsi, Adel; Schwarzacher, Trude; Kishii, Masahiro; Heslop-Harrison, J S

    2016-03-01

    Thinopyrum bessarabicum (2n = 2x = 14, JJ or E(b)E(b)) is a valuable source of genes for bread wheat (2n = 6x = 42) improvement because of its salinity tolerance and disease resistance. Development of wheat-Th. bessarabicum translocation lines by backcrossing the amphiploid in the absence of the Ph1 gene (allowing intergenomic recombination) can assist its utilization in wheat improvement. In this study, six novel wheat-Th. bessarabicum translocation lines involving different chromosome segments (T4BS.4BL-4JL, T6BS.6BL-6JL, T5AS.5AL-5JL, T5DL.5DS-5JS, T2BS.2BL-2JL, and the whole arm translocation T1JS.1AL) were identified and characterized using genomic in situ hybridization (GISH) and fluorescent in situ hybridization (FISH). No background translocations between wheat genomes were observed. The involvement of five of the seven chromosomes and small terminal segments of Th. bessarabicum chromosome arm were important, contributing to both reduced linkage drag of the derived lines by minimizing agronomically deleterious genes from the alien species and high stability including transmission of the alien segment. All three wheat genomes were involved in the translocations with the alien chromosome, and GISH showed the Th. bessarabicum genome was more closely related to the D genome in wheat. All the introgression lines were disomic, stable, and with good morphological characters. PMID:26238987

  15. Velocity-jump models with crowding effects

    NASA Astrophysics Data System (ADS)

    Treloar, Katrina K.; Simpson, Matthew J.; McCue, Scott W.

    2011-12-01

    Velocity-jump processes are discrete random-walk models that have many applications including the study of biological and ecological collective motion. In particular, velocity-jump models are often used to represent a type of persistent motion, known as a run and tumble, that is exhibited by some isolated bacteria cells. All previous velocity-jump processes are noninteracting, which means that crowding effects and agent-to-agent interactions are neglected. By neglecting these agent-to-agent interactions, traditional velocity-jump models are only applicable to very dilute systems. Our work is motivated by the fact that many applications in cell biology, such as wound healing, cancer invasion, and development, often involve tissues that are densely packed with cells where cell-to-cell contact and crowding effects can be important. To describe these kinds of high-cell-density problems using a velocity-jump process we introduce three different classes of crowding interactions into a one-dimensional model. Simulation data and averaging arguments lead to a suite of continuum descriptions of the interacting velocity-jump processes. We show that the resulting systems of hyperbolic partial differential equations predict the mean behavior of the stochastic simulations very well.

  16. Novel t(1;3)(q21,p21) translocation in a basal cell adenocarcinoma of the parotid gland: potential association with tumorigenesis.

    PubMed

    Saluja, Karan; Rao, Pulivarthi H; Myers, Jeffery N; El-Naggar, Adel K

    2016-08-01

    We report a rare translocation involving chromosomes 1q23 and 3p21 regions in a basaloid salivary carcinoma. Our case together with a previously reported instance of translocation involving chromosome 1q 21-24 region defines a specific chromosomal segment that may house a gene associated with the development of a subset of basaloid salivary tumors. PMID:27085552

  17. Bacterial translocation in experimental uremia.

    PubMed

    de Almeida Duarte, Joãn Bosco; de Aguilar-Nascimento, José Eduardo; Nascimento, Mariana; Nochi, Rubens Jardim

    2004-08-01

    The aim of this study was to investigate whether or not experimental uremia would induce bacterial translocation. Forty male Wistar rats were randomized into two groups: uremic (n = 20) and control (n = 20). Under anesthesia, the upper and lower left renal poles and the marginal lateral parenchyma were excised in uremic group. Seven days later, in a second operation, the liver, spleen and the mesenteric lymph nodes (MLN) were excised and cultured. Blood samples were sent for biochemical analysis (BUN, creatinine, sodium and potassium) and cultured. Specimens of the jejunum (1 cm below the Treitz angle) and ileum (1 cm above the ileocecal valve) were collected and sent for histological examination and scored for the degree of inflammation of the mucosa using a classification proposed by Chiu et al. in 1970. Uremic rats presented higher BUN, creatinine and potassium than controls. Bacterial translocation was more frequent in uremic than in control animals (8/20 (40%) vs. 1/20 (5%); p = 0.02). Translocation in uremic rats was observed mainly at the MLN (all eight cases). Both at the jejunum (uremic = 3 [0-5] vs. control = 2 [0-4]; p = 0.04) and the ileum (uremic - 2 [0-5] vs. control = 0 [0-3]; p = 0.01), inflammation score was higher in uremic rats than in controls. The intestinal mucosa barrier is impaired and bacterial translocation occurs in experimental uremia. PMID:15497213

  18. The influence of musical cadence into aquatic jumping jacks kinematics.

    PubMed

    Costa, Mário J; Oliveira, Cristiana; Teixeira, Genoveva; Marinho, Daniel A; Silva, António J; Barbosa, Tiago M

    2011-01-01

    The aim of this study was to analyze the relationships between the head-out aquatic exercise "Jumping jacks" kinematics and the musical cadence in healthy and fit subjects. Five young women, with at least one year of experience conducting head- out aquatic programs were videotaped in the frontal plane, with a pair of cameras providing a double projection (above and below the water surface). Subjects performed an incremental protocol of five bouts (120 b·min(-1), 135 b·min(-1), 150 b·min(-1), 165 b·min(-1) and 180 b·min(-1)) with 16 full cycles of the "Jumping jacks" exercise. Data processing and calculation of upper limbs' (i.e. hands), lower limbs' (i.e. feet) and center of mass' 2D linear velocity and displacement were computed with the software Ariel Performance Analysis System and applying the 2D-DLT algorithm. Subjects decreased the cycle period during the incremental protocol. Significant and negative relationships with the musical cadence were verified for the center of mass and upper limbs vertical displacement. On the other hand, for the lower limbs lateral velocity, a significant and positive relationship was observed. It is concluded that expert and fit subjects increase the lower limb's velocity to maintain the range of motion, while the upper limb's displacement is reduced to coupe the music cadence. Key pointsWhile performing the Jumping Jacks, expert and fit subjects increase their lower limbs segmental velocity to maintain the range of motion.The upper limbs displacement is reduced to maintain the music cadence.Expert and fit subjects present similar response for alternating or simultaneously head-out aquatic exercises when increasing the music cadence. PMID:24149548

  19. Motor Control of Landing from a Jump in Simulated Hypergravity.

    PubMed

    Gambelli, Clément N; Theisen, Daniel; Willems, Patrick A; Schepens, Bénédicte

    2015-01-01

    On Earth, when landing from a counter-movement jump, muscles contract before touchdown to anticipate imminent collision with the ground and place the limbs in a proper position. This study assesses how the control of landing is modified when gravity is increased above 1 g. Hypergravity was simulated in two different ways: (1) by generating centrifugal forces during turns of an aircraft (A300) and (2) by pulling the subject downwards in the laboratory with a Subject Loading System (SLS). Eight subjects were asked to perform counter-movement jumps at 1 g on Earth and at 3 hypergravity levels (1.2, 1.4 and 1.6 g) both in A300 and with SLS. External forces applied to the body, movements of the lower limb segments and muscular activity of 6 lower limb muscles were recorded. Our results show that both in A300 and with SLS, as in 1 g: (1) the anticipation phase is present; (2) during the loading phase (from touchdown until the peak of vertical ground reaction force), lower limb muscles act like a stiff spring, whereas during the second part (from the peak of vertical ground reaction force until the return to the standing position), they act like a compliant spring associated with a damper. (3) With increasing gravity, the preparatory adjustments and the loading phase are modified whereas the second part does not change drastically. (4) The modifications are similar in A300 and with SLS, however the effect of hypergravity is accentuated in A300, probably due to altered sensory inputs. This observation suggests that otolithic information plays an important role in the control of the landing from a jump. PMID:26505472

  20. Motor Control of Landing from a Jump in Simulated Hypergravity

    PubMed Central

    Gambelli, Clément N.; Theisen, Daniel; Willems, Patrick A.; Schepens, Bénédicte

    2015-01-01

    On Earth, when landing from a counter-movement jump, muscles contract before touchdown to anticipate imminent collision with the ground and place the limbs in a proper position. This study assesses how the control of landing is modified when gravity is increased above 1 g. Hypergravity was simulated in two different ways: (1) by generating centrifugal forces during turns of an aircraft (A300) and (2) by pulling the subject downwards in the laboratory with a Subject Loading System (SLS). Eight subjects were asked to perform counter-movement jumps at 1 g on Earth and at 3 hypergravity levels (1.2, 1.4 and 1.6 g) both in A300 and with SLS. External forces applied to the body, movements of the lower limb segments and muscular activity of 6 lower limb muscles were recorded. Our results show that both in A300 and with SLS, as in 1 g: (1) the anticipation phase is present; (2) during the loading phase (from touchdown until the peak of vertical ground reaction force), lower limb muscles act like a stiff spring, whereas during the second part (from the peak of vertical ground reaction force until the return to the standing position), they act like a compliant spring associated with a damper. (3) With increasing gravity, the preparatory adjustments and the loading phase are modified whereas the second part does not change drastically. (4) The modifications are similar in A300 and with SLS, however the effect of hypergravity is accentuated in A300, probably due to altered sensory inputs. This observation suggests that otolithic information plays an important role in the control of the landing from a jump. PMID:26505472

  1. Determination of LIII subshell absorption jump ratio and jump factor of wolfram

    NASA Astrophysics Data System (ADS)

    Cengiz, Erhan; Saritas, Nuriye

    2014-04-01

    The LIII subshell absorption jump ratio and jump factor of wolfram have been measured by two different methods. In the first method the mass attenuation coefficients have been obtained by narrow beam transmission geometry to calculate the LIII subshell absorption jump ratio and jump factor. In the latter these parameters have been derived from the LIII subshell X-ray production and the photoionization cross sections of the LIII subshell and higher subshells determined by Energy Dispersive X-ray Fluorescence technique and narrow beam transmission geometry, respectively. The results obtained by both methods have been compared with theoretical and experimental values. They are in good agreement with each other.

  2. Jump Horse Safety: Reconciling Public Debate and Australian Thoroughbred Jump Racing Data, 2012-2014.

    PubMed

    Ruse, Karen; Davison, Aidan; Bridle, Kerry

    2015-01-01

    Thoroughbred jump racing sits in the spotlight of contemporary welfare and ethical debates about horse racing. In Australia, jump racing comprises hurdle and steeplechase races and has ceased in all but two states, Victoria and South Australia. This paper documents the size, geography, composition, and dynamics of Australian jump racing for the 2012, 2013, and 2014 seasons with a focus on debate about risks to horses. We found that the majority of Australian jump racing is regional, based in Victoria, and involves a small group of experienced trainers and jockeys. Australian jump horses are on average 6.4 years of age. The jump career of the majority of horses involves participating in three or less hurdle races and over one season. Almost one quarter of Australian jump horses race only once. There were ten horse fatalities in races over the study period, with an overall fatality rate of 5.1 fatalities per 1000 horses starting in a jump race (0.51%). There was significant disparity between the fatality rate for hurdles, 0.75 fatalities per 1000 starts (0.075%) and steeplechases, 14 fatalities per 1000 starts (1.4%). Safety initiatives introduced by regulators in 2010 appear to have significantly decreased risks to horses in hurdles but have had little or no effect in steeplechases. Our discussion considers these Animals 2015, 5 1073 data in light of public controversy, political debate, and industry regulation related to jump horse safety. PMID:26506396

  3. Collophore may help direct springtail jump

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The collophore of specimens of Entomobrya multifasciata (Tullberg 1871) is composed of four segments. The third segment telescopes in and out of the second and the fourth is an eversible vesicle that is entirely enclosed in the third when not deployed. The four segments are each likely serial homolo...

  4. Driven polymer translocation in good and bad solvent: Effects of hydrodynamics and tension propagation.

    PubMed

    Moisio, J E; Piili, J; Linna, R P

    2016-08-01

    We investigate the driven polymer translocation through a nanometer-scale pore in the presence and absence of hydrodynamics both in good and bad solvent. We present our results on tension propagating along the polymer segment on the cis side that is measured for the first time using our method that works also in the presence of hydrodynamics. For simulations we use stochastic rotation dynamics, also called multiparticle collision dynamics. We find that in the good solvent the tension propagates very similarly whether hydrodynamics is included or not. Only the tensed segment is by a constant factor shorter in the presence of hydrodynamics. The shorter tensed segment and the hydrodynamic interactions contribute to a smaller friction for the translocating polymer when hydrodynamics is included, which shows as smaller waiting times and a smaller exponent in the scaling of the translocation time with the polymer length. In the bad solvent hydrodynamics has a minimal effect on polymer translocation, in contrast to the good solvent, where it speeds up translocation. We find that under bad-solvent conditions tension does not spread appreciably along the polymer. Consequently, translocation time does not scale with the polymer length. By measuring the effective friction in a setup where a polymer in free solvent is pulled by a constant force at the end, we find that hydrodynamics does speed up collective polymer motion in the bad solvent even more effectively than in the good solvent. However, hydrodynamics has a negligible effect on the motion of individual monomers within the highly correlated globular conformation on the cis side and hence on the entire driven translocation under bad-solvent conditions. PMID:27627352

  5. Understanding Vertical Jump Potentiation: A Deterministic Model.

    PubMed

    Suchomel, Timothy J; Lamont, Hugh S; Moir, Gavin L

    2016-06-01

    This review article discusses previous postactivation potentiation (PAP) literature and provides a deterministic model for vertical jump (i.e., squat jump, countermovement jump, and drop/depth jump) potentiation. There are a number of factors that must be considered when designing an effective strength-power potentiation complex (SPPC) focused on vertical jump potentiation. Sport scientists and practitioners must consider the characteristics of the subject being tested and the design of the SPPC itself. Subject characteristics that must be considered when designing an SPPC focused on vertical jump potentiation include the individual's relative strength, sex, muscle characteristics, neuromuscular characteristics, current fatigue state, and training background. Aspects of the SPPC that must be considered for vertical jump potentiation include the potentiating exercise, level and rate of muscle activation, volume load completed, the ballistic or non-ballistic nature of the potentiating exercise, and the rest interval(s) used following the potentiating exercise. Sport scientists and practitioners should design and seek SPPCs that are practical in nature regarding the equipment needed and the rest interval required for a potentiated performance. If practitioners would like to incorporate PAP as a training tool, they must take the athlete training time restrictions into account as a number of previous SPPCs have been shown to require long rest periods before potentiation can be realized. Thus, practitioners should seek SPPCs that may be effectively implemented in training and that do not require excessive rest intervals that may take away from valuable training time. Practitioners may decrease the necessary time needed to realize potentiation by improving their subject's relative strength. PMID:26712510

  6. Jump Horse Safety: Reconciling Public Debate and Australian Thoroughbred Jump Racing Data, 2012–2014

    PubMed Central

    Ruse, Karen; Davison, Aidan; Bridle, Kerry

    2015-01-01

    Simple Summary This paper documents the dynamics of Australian thoroughbred jump racing in the 2012, 2013, and 2014 seasons with the aim of informing debate about risks to horses and the future of this activity. We conclude that the safety of Australian jump racing has improved in recent years but that steeplechases are considerably riskier for horses than hurdle races. Abstract Thoroughbred jump racing sits in the spotlight of contemporary welfare and ethical debates about horse racing. In Australia, jump racing comprises hurdle and steeplechase races and has ceased in all but two states, Victoria and South Australia. This paper documents the size, geography, composition, and dynamics of Australian jump racing for the 2012, 2013, and 2014 seasons with a focus on debate about risks to horses. We found that the majority of Australian jump racing is regional, based in Victoria, and involves a small group of experienced trainers and jockeys. Australian jump horses are on average 6.4 years of age. The jump career of the majority of horses involves participating in three or less hurdle races and over one season. Almost one quarter of Australian jump horses race only once. There were ten horse fatalities in races over the study period, with an overall fatality rate of 5.1 fatalities per 1000 horses starting in a jump race (0.51%). There was significant disparity between the fatality rate for hurdles, 0.75 fatalities per 1000 starts (0.075%) and steeplechases, 14 fatalities per 1000 starts (1.4%). Safety initiatives introduced by regulators in 2010 appear to have significantly decreased risks to horses in hurdles but have had little or no effect in steeplechases. Our discussion considers these data in light of public controversy, political debate, and industry regulation related to jump horse safety. PMID:26506396

  7. A locust-inspired miniature jumping robot.

    PubMed

    Zaitsev, Valentin; Gvirsman, Omer; Ben Hanan, Uri; Weiss, Avi; Ayali, Amir; Kosa, Gabor

    2015-12-01

    Unmanned ground vehicles are mostly wheeled, tracked, or legged. These locomotion mechanisms have a limited ability to traverse rough terrain and obstacles that are higher than the robot's center of mass. In order to improve the mobility of small robots it is necessary to expand the variety of their motion gaits. Jumping is one of nature's solutions to the challenge of mobility in difficult terrain. The desert locust is the model for the presented bio-inspired design of a jumping mechanism for a small mobile robot. The basic mechanism is similar to that of the semilunar process in the hind legs of the locust, and is based on the cocking of a torsional spring by wrapping a tendon-like wire around the shaft of a miniature motor. In this study we present the jumping mechanism design, and the manufacturing and performance analysis of two demonstrator prototypes. The most advanced jumping robot demonstrator is power autonomous, weighs 23 gr, and is capable of jumping to a height of 3.35 m, covering a distance of 1.37 m. PMID:26602094

  8. The Physics of Equestrian Show Jumping

    NASA Astrophysics Data System (ADS)

    Stinner, Art

    2014-04-01

    This article discusses the kinematics and dynamics of equestrian show jumping. For some time I have attended a series of show jumping events at Spruce Meadows, an international equestrian center near Calgary, Alberta, often referred to as the "Wimbledon of equestrian jumping." I have always had a desire to write an article such as this one, but when I searched the Internet for information and looked at YouTube presentations, I could only find simplistic references to Newton's laws and the conservation of mechanical energy principle. Nowhere could I find detailed calculations. On the other hand, there were several biomechanical articles with empirical reports of the results of kinetic and dynamic investigations of show jumping using high-speed digital cameras and force plates. They summarize their results in tables that give information about the motion of a horse jumping over high fences (1.40 m) and the magnitudes of the forces encountered when landing. However, they do not describe the physics of these results.

  9. [Segmental neurofibromatosis].

    PubMed

    Zulaica, A; Peteiro, C; Pereiro, M; Pereiro Ferreiros, M; Quintas, C; Toribio, J

    1989-01-01

    Four cases of segmental neurofibromatosis (SNF) are reported. It is a rare entity considered to be a localized variant of neurofibromatosis (NF)-Riccardi's type V. Two cases are male and two female. The lesions are located to the head in a patient and the other three cases in the trunk. No family history nor transmission to progeny were manifested. The rest of the organs are undamaged. PMID:2502696

  10. Critical Jump Distance for Propagating Earthquake Ruptures Across Step-Overs

    NASA Astrophysics Data System (ADS)

    Yıkılmaz, M. B.; Turcotte, D. L.; Heien, E. M.; Kellogg, L. H.; Rundle, J. B.

    2015-08-01

    The geometry of a strike-slip fault system is an important component that influences the kinematics and interactions of the various faults within the system. Discontinuities and bends in the fault geometry not only determine the types of structures and the physiography that we observe along the fault system but also have a significant influence on the propagation of earthquake ruptures. A precise knowledge of the fault geometry, especially how it is segmented and other physical parameters, is essential for seismic hazard analysis. It is known that earthquake ruptures sometimes propagate over multiple faults by jumping from one segment to the next. A fault jump is a sudden dynamic coalescence of two faults separated by a step-over. Field observations suggest that a step-over width of 5 km is an appropriate maximum jump distance. Our study shows that between 2.5 and 6.5 km of step-over width, the probability of fault jump, for both releasing and restraining step-overs, decreases significantly from 100 to <10 %.

  11. Comparing Fast Pressure Jump and Temperature Jump Protein Folding Experiments and Simulations

    PubMed Central

    Prigozhin, Maxim B.; Schulten, Klaus; Gruebele, Martin

    2016-01-01

    The unimolecular folding reaction of small proteins is now amenable to a very direct mechanistic comparison between experiment and simulation. We present such a comparison of microsecond pressure and temperature jump refolding kinetics of the engineered WW domain FiP35, a model system for beta sheet folding. Both perturbations produce experimentally a faster and a slower kinetic phase, the “slow” microsecond phase being activated. The fast phase shows differences between perturbation methods and is closer to the downhill limit by temperature jump, but closer to the transiently populated intermediate limit by pressure jump. These observations make more demands on simulations of the folding process than just a rough comparison of time scales. To complement experiments, we calculated several pressure jump and temperature jump all-atom molecular dynamics trajectories in explicit solvent, where FiP35 folded in five of the six simulations. We analyzed our pressure jump simulations by kinetic modeling and found that the pressure jump experiments and MD simulations are most consistent with a 4-state kinetic mechanism. Together, our experimental and computational data highlight FiP35’s position at the boundary where activated intermediates and downhill folding meet, and we show that this model protein is an excellent candidate for further pressure jump molecular dynamics studies to compare experiment and modeling at the folding mechanism level. PMID:25988868

  12. Determination of the Best Pre-Jump Height for Improvement of Two-Legged Vertical Jump

    PubMed Central

    Jafari, Mahsa; Zolaktaf, Vahid; Marandi, Sayyed M

    2013-01-01

    Background: Athletic performance in many sports depends on two-legged vertical jump. The objective of this study was to examine the effect of different pre-jump height exercises on two-legged vertical jump and to determine the best pre-jump height(s). Methods: Subjects included 35 females and 42 males. By matched randomized sampling, subjects of each sex were assigned into four groups, namely, control, 10-cm hurdle, 20-cm hurdle, and 30-cm hurdle. They participated in the same training program for 6 weeks. Statistical analyses were based on one-way and repeated-measure analysis of variance (ANOVA). Results: Analysis of the data showed that practice over hurdles of 10 cm was better than no hurdle and hurdles of >10 cm. Also, jump attempts over hurdles were efficient for trained athletes, but not for untrained athletes. For both sexes, the rate of spike improvement was much better in the experimental groups than in the control groups; it was independent from the rate of progress in jump, which was relatively less evident. Conclusions: It is likely that rather than increasing jump height, training over hurdle enabled the players to use a higher percent of their jump potentials. PMID:23717758

  13. Increase in Jumping Height Associated with Maximal Effort Vertical Depth Jumps.

    ERIC Educational Resources Information Center

    Bedi, John F.; And Others

    1987-01-01

    In order to assess if there existed a statistically significant increase in jumping performance when dropping from different heights, 32 males, aged 19 to 26, performed a series of maximal effort vertical jumps after dropping from eight heights onto a force plate. Results are analyzed. (Author/MT)

  14. Double aneuploidy: partial trisomy 21 and XO/XXX in a family with 12/21 translocation.

    PubMed

    Chen, H; Tyrkus, M; Woolley, P V

    1978-09-01

    A female patient with mild mental retardation with spatial perceptual difficulties, microcephaly, depressed nasal root, receding chin, webbed neck, low hairline, shield chest, cubitus valgus, scoliosis and dermatoglyphic findings not characteristic of Down's syndrome is reported. In addition to X/XXX, she had a partial trisomy 21 of the short arm-centromere-proximal long arm segment due to maternal t(12;21) translocation. Two phenotypically normal siblings carried the balanced translocation. PMID:315194

  15. Jumping of water striders on water

    NASA Astrophysics Data System (ADS)

    Yang, Eunjin; Son, Jaehak; Jablonski, Piotr; Kim, Ho-Young

    2012-11-01

    Small insects such as water striders, springtails, fishing spiders freely move on water by adopting various modes of locomotion, such as rowing, galloping, jumping and meniscus-climbing. As the physics of jumping have not yet been fully understood among those ways of semi-aquatic propulsion, here we present the results of a combined experimental and theoretical investigation of the dynamics of water striders leaping off water. We first image and analyze the trajectories of the legs and body of jumping water striders of three different species with a high-speed camera. We then theoretically compute the forces acting on the body by considering the capillary interaction between the flexible legs and deforming water meniscus. Our theory enables us to predict the maximum take-off speed for given leg lengths. The experimental measurements suggest that the water striders drive their legs near the optimal speed to gain the maximum take-off speed.

  16. Popcorn: critical temperature, jump and sound

    PubMed Central

    Virot, Emmanuel; Ponomarenko, Alexandre

    2015-01-01

    Popcorn bursts open, jumps and emits a ‘pop’ sound in some hundredths of a second. The physical origin of these three observations remains unclear in the literature. We show that the critical temperature 180°C at which almost all of popcorn pops is consistent with an elementary pressure vessel scenario. We observe that popcorn jumps with a ‘leg’ of starch which is compressed on the ground. As a result, popcorn is midway between two categories of moving systems: explosive plants using fracture mechanisms and jumping animals using muscles. By synchronizing video recordings with acoustic recordings, we propose that the familiar ‘pop’ sound of the popcorn is caused by the release of water vapour. PMID:25673298

  17. Jumping, snapping and popping at nanometer scale

    NASA Astrophysics Data System (ADS)

    Haviland, David

    2015-03-01

    The 'jump-to-contact' instability is well known in Atomic Force Microscopy. When a tip attached to a soft cantilever approaches a surface, the large attractive force gradient disrupts the quasi-static force balance and the tip snaps in to contact with the surface. Less appreciated is the converse instability, where a soft liquid-like polymer surface jumps to meet the tip. This nano-scale pop is inaudible, but it does leave a distinctive signature if one carefully monitors the cantilever's steady state dynamics when driven with multiple tones. The nonlinear tip-surface interaction causes intermodulation, or frequency mixing of the drive tones. When many intermodulation products are measured close to the cantilever resonance the spectrum can be transformed to reveal the in-phase and quadrature forces acting on the tip, as a function of oscillation amplitude. We present experimental measurements and theoretical modelling that reveal this surface-jump-to-tip instability.

  18. Popcorn: critical temperature, jump and sound.

    PubMed

    Virot, Emmanuel; Ponomarenko, Alexandre

    2015-03-01

    Popcorn bursts open, jumps and emits a 'pop' sound in some hundredths of a second. The physical origin of these three observations remains unclear in the literature. We show that the critical temperature 180°C at which almost all of popcorn pops is consistent with an elementary pressure vessel scenario. We observe that popcorn jumps with a 'leg' of starch which is compressed on the ground. As a result, popcorn is midway between two categories of moving systems: explosive plants using fracture mechanisms and jumping animals using muscles. By synchronizing video recordings with acoustic recordings, we propose that the familiar 'pop' sound of the popcorn is caused by the release of water vapour. PMID:25673298

  19. BIOMECHANICS. Jumping on water: Surface tension-dominated jumping of water striders and robotic insects.

    PubMed

    Koh, Je-Sung; Yang, Eunjin; Jung, Gwang-Pil; Jung, Sun-Pill; Son, Jae Hak; Lee, Sang-Im; Jablonski, Piotr G; Wood, Robert J; Kim, Ho-Young; Cho, Kyu-Jin

    2015-07-31

    Jumping on water is a unique locomotion mode found in semi-aquatic arthropods, such as water striders. To reproduce this feat in a surface tension-dominant jumping robot, we elucidated the hydrodynamics involved and applied them to develop a bio-inspired impulsive mechanism that maximizes momentum transfer to water. We found that water striders rotate the curved tips of their legs inward at a relatively low descending velocity with a force just below that required to break the water surface (144 millinewtons/meter). We built a 68-milligram at-scale jumping robotic insect and verified that it jumps on water with maximum momentum transfer. The results suggest an understanding of the hydrodynamic phenomena used by semi-aquatic arthropods during water jumping and prescribe a method for reproducing these capabilities in artificial systems. PMID:26228144

  20. Suitability of amphibians and reptiles for translocation.

    PubMed

    Germano, Jennifer M; Bishop, Phillip J

    2009-02-01

    Translocations are important tools in the field of conservation. Despite increased use over the last few decades, the appropriateness of translocations for amphibians and reptiles has been debated widely over the past 20 years. To provide a comprehensive evaluation of the suitability of amphibians and reptiles for translocation, we reviewed the results of amphibian and reptile translocation projects published between 1991 and 2006. The success rate of amphibian and reptile translocations reported over this period was twice that reported in an earlier review in 1991. Success and failure rates were independent of the taxonomic class (Amphibia or Reptilia) released. Reptile translocations driven by human-wildlife conflict mitigation had a higher failure rate than those motivated by conservation, and more recent projects of reptile translocations had unknown outcomes. The outcomes of amphibian translocations were significantly related to the number of animals released, with projects releasing over 1000 individuals being most successful. The most common reported causes of translocation failure were homing and migration of introduced individuals out of release sites and poor habitat. The increased success of amphibian and reptile translocations reviewed in this study compared with the 1991 review is encouraging for future conservation projects. Nevertheless, more preparation, monitoring, reporting of results, and experimental testing of techniques and reintroduction questions need to occur to improve translocations of amphibians and reptiles as a whole. PMID:19143783

  1. Recent Advancements in Lightning Jump Algorithm Work

    NASA Technical Reports Server (NTRS)

    Schultz, Christopher J.; Petersen, Walter A.; Carey, Lawrence D.

    2010-01-01

    In the past year, the primary objectives were to show the usefulness of total lightning as compared to traditional cloud-to-ground (CG) networks, test the lightning jump algorithm configurations in other regions of the country, increase the number of thunderstorms within our thunderstorm database, and to pinpoint environments that could prove difficult for any lightning jump configuration. A total of 561 thunderstorms have been examined in the past year (409 non-severe, 152 severe) from four regions of the country (North Alabama, Washington D.C., High Plains of CO/KS, and Oklahoma). Results continue to indicate that the 2 lightning jump algorithm configuration holds the most promise in terms of prospective operational lightning jump algorithms, with a probability of detection (POD) at 81%, a false alarm rate (FAR) of 45%, a critical success index (CSI) of 49% and a Heidke Skill Score (HSS) of 0.66. The second best performing algorithm configuration was the Threshold 4 algorithm, which had a POD of 72%, FAR of 51%, a CSI of 41% and an HSS of 0.58. Because a more complex algorithm configuration shows the most promise in terms of prospective operational lightning jump algorithms, accurate thunderstorm cell tracking work must be undertaken to track lightning trends on an individual thunderstorm basis over time. While these numbers for the 2 configuration are impressive, the algorithm does have its weaknesses. Specifically, low-topped and tropical cyclone thunderstorm environments are present issues for the 2 lightning jump algorithm, because of the suppressed vertical depth impact on overall flash counts (i.e., a relative dearth in lightning). For example, in a sample of 120 thunderstorms from northern Alabama that contained 72 missed events by the 2 algorithm 36% of the misses were associated with these two environments (17 storms).

  2. Linkage map construction involving a reciprocal translocation.

    PubMed

    Farré, A; Benito, I Lacasa; Cistué, L; de Jong, J H; Romagosa, I; Jansen, J

    2011-03-01

    This paper is concerned with a novel statistical-genetic approach for the construction of linkage maps in populations obtained from reciprocal translocation heterozygotes of barley (Hordeum vulgare L.). Using standard linkage analysis, translocations usually lead to 'pseudo-linkage': the mixing up of markers from the chromosomes involved in the translocation into a single linkage group. Close to the translocation breakpoints recombination is severely suppressed and, as a consequence, ordering markers in those regions is not feasible. The novel strategy presented in this paper is based on (1) disentangling the "pseudo-linkage" using principal coordinate analysis, (2) separating individuals into translocated types and normal types and (3) separating markers into those close to and those more distant from the translocation breakpoints. The methods make use of a consensus map of the species involved. The final product consists of integrated linkage maps of the distal parts of the chromosomes involved in the translocation. PMID:21153624

  3. How do elite ski jumpers handle the dynamic conditions in imitation jumps?

    PubMed

    Ettema, Gertjan; Hooiveld, Jo; Braaten, Steinar; Bobbert, Maarten

    2016-01-01

    We examined the effect of boundary conditions in imitation ski jumping on movement dynamics and coordination. We compared imitation ski jumps with--and without--the possibility to generate shear propulsion forces. Six elite ski jumpers performed imitation jumps by jumping from a fixed surface and from a rolling platform. The ground reaction force vector, kinematics of body segments, and EMG of eight lower limb muscles were recorded. Net joint dynamics were calculated using inverse dynamics. The two imitation jumps differed considerably from each other with regard to the dynamics (moments, forces), whereas the kinematics were very similar. Knee power was higher and hip power was lower on the rolling platform than on the fixed surface. Mean EMG levels were very similar for both conditions, but differences in the development of muscle activity were indicated for seven of eight muscles. These differences are reflected in a subtle difference of the alignment of ground reaction force with centre of mass: the ground reaction force runs continuously close to but behind the centre of mass on the rolling platform and fluctuates around it on the fixed surface. This likely reflects a different strategy for controlling angular momentum. PMID:26368027

  4. Humans make near-optimal adjustments of control to initial body configuration in vertical squat jumping.

    PubMed

    Bobbert, Maarten F; Richard Casius, L J; Kistemaker, Dinant A

    2013-05-01

    We investigated adjustments of control to initial posture in squat jumping. Eleven male subjects jumped from three initial postures: preferred initial posture (PP), a posture in which the trunk was rotated 18° more backward (BP) and a posture in which it was rotated 15° more forward (FP) than in PP. Kinematics, ground reaction forces and electromyograms (EMG) were collected. EMG was rectified and smoothed to obtain smoothed rectified EMG (srEMG). Subjects showed adjustments in srEMG histories, most conspicuously a shift in srEMG-onset of rectus femoris (REC): from early in BP to late in FP. Jumps from the subjects' initial postures were simulated with a musculoskeletal model comprising four segments and six Hill-type muscles, which had muscle stimulation (STIM) over time as input. STIM of each muscle changed from initial to maximal at STIM-onset, and STIM-onsets were optimized using jump height as criterion. Optimal simulated jumps from BP, PP and FP were similar to jumps of the subjects. Optimal solutions primarily differed in STIM-onset of REC: from early in BP to late in FP. Because the subjects' adjustments in srEMG-onsets were similar to adjustments of the model's optimal STIM-onsets, it was concluded that the former were near-optimal. With the model we also showed that near-maximum jumps from BP, PP and FP could be achieved when STIM-onset of REC depended on initial hip joint angle and STIM-onsets of the other muscles were posture-independent. A control theory that relies on a mapping from initial posture to STIM-onsets seems a parsimonious alternative to theories relying on internal optimal control models. PMID:23384608

  5. Jumping in frogs: assessing the design of the skeletal system by anatomically realistic modeling and forward dynamic simulation.

    PubMed

    Kargo, William J; Nelson, Frank; Rome, Lawrence C

    2002-06-01

    Comparative musculoskeletal modeling represents a tool to understand better how motor system parameters are fine-tuned for specific behaviors. Frog jumping is a behavior in which the physical properties of the body and musculotendon actuators may have evolved specifically to extend the limits of performance. Little is known about how the joints of the frog contribute to and limit jumping performance. To address these issues, we developed a skeletal model of the frog Rana pipiens that contained realistic bones, joints and body-segment properties. We performed forward dynamic simulations of jumping to determine the minimal number of joint degrees of freedom required to produce maximal-distance jumps and to produce jumps of varied take-off angles. The forward dynamics of the models was driven with joint torque patterns determined from inverse dynamic analysis of jumping in experimental frogs. When the joints were constrained to rotate in the extension-flexion plane, the simulations produced short jumps with a fixed angle of take-off. We found that, to produce maximal-distance jumping, the skeletal system of the frog must minimally include a gimbal joint at the hip (three rotational degrees of freedom), a universal Hooke's joint at the knee (two rotational degrees of freedom) and pin joints at the ankle, tarsometatarsal, metatarsophalangeal and iliosacral joints (one rotational degree of freedom). One of the knee degrees of freedom represented a unique kinematic mechanism (internal rotation about the long axis of the tibiofibula) and played a crucial role in bringing the feet under the body so that maximal jump distances could be attained. Finally, the out-of-plane degrees of freedom were found to be essential to enable the frog to alter the angle of take-off and thereby permit flexible neuromotor control. The results of this study form a foundation upon which additional model subsystems (e.g. musculotendon and neural) can be added to test the integrative action of the

  6. A sugar chain at a specific position in the nascent polypeptide chain induces forward movement during translocation through the translocon.

    PubMed

    Yamagishi, Marifu; Fujita, Hidenobu; Morimoto, Fumiko; Kida, Yuichiro; Sakaguchi, Masao

    2011-05-01

    Nascent polypeptide chains synthesized by membrane bound ribosomes are cotranslationally translocated through and integrated into the endoplasmic reticulum translocon. Hydrophobic segments and positive charges on the chain are critical to halt the ongoing translocation. A marginally hydrophobic segment, which cannot be inserted into the membrane by itself, can be a transmembrane segment depending on its downstream positive charges. In certain conditions, positive charges even 60 residues downstream cause the marginally hydrophobic segment to span the membrane by inducing the segment to slide back from the lumen. Here we systematically examined the effect of a core sugar chain on the fate of a marginally hydrophobic segment using a cell-free translation and translocation system. A sugar chain added within 12 residues upstream of the marginally hydrophobic segment prevents the sliding back and promotes forward movement of the polypeptide chain. The sugar chain apparently functions as a ratchet to keep the polypeptide chain in the lumen. We propose that the sugar chain is a third topology determinant of membrane proteins, in addition to a hydrophobic segment and positive charges of the nascent chain. PMID:21278156

  7. Segmental neurofibromatosis.

    PubMed

    Sobjanek, Michał; Dobosz-Kawałko, Magdalena; Michajłowski, Igor; Pęksa, Rafał; Nowicki, Roman

    2014-12-01

    Segmental neurofibromatosis or type V neurofibromatosis is a rare genodermatosis characterized by neurofibromas, café-au-lait spots and neurofibromas limited to a circumscribed body region. The disease may be associated with systemic involvement and malignancies. The disorder has not been reported yet in the Polish medical literature. A 63-year-old Caucasian woman presented with a 20-year history of multiple, flesh colored, dome-shaped, soft to firm nodules situated in the right lumbar region. A histopathologic evaluation of three excised tumors revealed neurofibromas. No neurological and ophthalmologic symptoms of neurofibromatosis were diagnosed. PMID:25610358

  8. Segmental neurofibromatosis.

    PubMed

    Adigun, Chris G; Stein, Jennifer

    2011-01-01

    A 59-year-old man presented for evaluation and excision of non-tender, fleshy nodules that were arranged in a dermatomal distribution from the left side of the chest to the left axilla. A biopsy specimen of a nodule was consistent with a neurofibroma. Owing to the lack of other cutaneous findings, the lack of a family history of neurofibromatosis, and the dermatomal distribution of the neurofibromas, this patient met the criteria for a diagnosis of segmental neurofibromatosis (SNF) according to Riccardi's definition of SNF and classification of neurofibromatosis. Because the patient has no complications of neurofibromatosis 1 no medical treatment is required. PMID:22031651

  9. Segmental neurofibromatosis

    PubMed Central

    Dobosz-Kawałko, Magdalena; Michajłowski, Igor; Pęksa, Rafał; Nowicki, Roman

    2014-01-01

    Segmental neurofibromatosis or type V neurofibromatosis is a rare genodermatosis characterized by neurofibromas, café-au-lait spots and neurofibromas limited to a circumscribed body region. The disease may be associated with systemic involvement and malignancies. The disorder has not been reported yet in the Polish medical literature. A 63-year-old Caucasian woman presented with a 20-year history of multiple, flesh colored, dome-shaped, soft to firm nodules situated in the right lumbar region. A histopathologic evaluation of three excised tumors revealed neurofibromas. No neurological and ophthalmologic symptoms of neurofibromatosis were diagnosed. PMID:25610358

  10. Performance analysis of jump-gliding locomotion for miniature robotics.

    PubMed

    Vidyasagar, A; Zufferey, Jean-Christohphe; Floreano, Dario; Kovač, M

    2015-04-01

    Recent work suggests that jumping locomotion in combination with a gliding phase can be used as an effective mobility principle in robotics. Compared to pure jumping without a gliding phase, the potential benefits of hybrid jump-gliding locomotion includes the ability to extend the distance travelled and reduce the potentially damaging impact forces upon landing. This publication evaluates the performance of jump-gliding locomotion and provides models for the analysis of the relevant dynamics of flight. It also defines a jump-gliding envelope that encompasses the range that can be achieved with jump-gliding robots and that can be used to evaluate the performance and improvement potential of jump-gliding robots. We present first a planar dynamic model and then a simplified closed form model, which allow for quantification of the distance travelled and the impact energy on landing. In order to validate the prediction of these models, we validate the model with experiments using a novel jump-gliding robot, named the 'EPFL jump-glider'. It has a mass of 16.5 g and is able to perform jumps from elevated positions, perform steered gliding flight, land safely and traverse on the ground by repetitive jumping. The experiments indicate that the developed jump-gliding model fits very well with the measured flight data using the EPFL jump-glider, confirming the benefits of jump-gliding locomotion to mobile robotics. The jump-glide envelope considerations indicate that the EPFL jump-glider, when traversing from a 2 m height, reaches 74.3% of optimal jump-gliding distance compared to pure jumping without a gliding phase which only reaches 33.4% of the optimal jump-gliding distance. Methods of further improving flight performance based on the models and inspiration from biological systems are presented providing mechanical design pathways to future jump-gliding robot designs. PMID:25811417

  11. The epidemiology of injury in bungee jumping, BASE jumping, and skydiving.

    PubMed

    Søreide, Kjetil

    2012-01-01

    Knowledge regarding epidemiology of injury is of benefit to injury prevention of activities associated with high risk. As relatively 'young' activities, the investigation of injuries and deaths related in extreme sports such as bungee jumping and BASE jumping is relatively sparse. Studies evaluating risk in civilian and military skydiving activities have been reported over the past decades, but technique and equipment has changed. Risk with bungee jumping is only sporadically reported in the literature, most often in connection with eye injuries, but also rare events of serious, life-threatening injuries and even death. BASE is an acronym for Building, Antenna, Span, Earth, which represents the fixed objects from which jumps are made. Estimated risk in BASE jumping for any injury (independent of severity grade) is 0.4-0.5%, which as 5- to 8-fold higher than skydiving. Typically, men outnumber women in a ratio of 10:1 in both injuries and case fatality rates. Age is frequently reported to range from 30 to 40 years. Notably, differences in training and environmental locations exist between recreational skydiving and BASE jumping. As BASE jumps are made from lower altitudes than skydives, jumpers generally fall at lower speeds, have far less aerodynamic control, and may lose flying stability. Yet, typical injuries include a bruised or sprained ankle during landing. Protective gear including helmet and pads may help to prevent such injuries, while more complex knowledge of human factors, environment and training are needed to prevent fatal injuries. PMID:22824842

  12. Jumping on the Social Media Bandwagon

    ERIC Educational Resources Information Center

    Blakeslee, Lori

    2012-01-01

    Should a school district jump on the social media bandwagon? Yes! Social media provide a low-cost way to communicate school district priorities, influence decision makers, and tell its story without filters. Equally important, social media are where constituents are spending a lot of their time. With more than 800 million members, Facebook is an…

  13. The walk and jump of Equisetum spores.

    PubMed

    Marmottant, Philippe; Ponomarenko, Alexandre; Bienaimé, Diane

    2013-11-01

    Equisetum plants (horsetails) reproduce by producing tiny spherical spores that are typically 50 µm in diameter. The spores have four elaters, which are flexible ribbon-like appendages that are initially wrapped around the main spore body and that deploy upon drying or fold back in humid air. If elaters are believed to help dispersal, the exact mechanism for spore motion remains unclear in the literature. In this manuscript, we present observations of the 'walks' and 'jumps' of Equisetum spores, which are novel types of spore locomotion mechanisms compared to the ones of other spores. Walks are driven by humidity cycles, each cycle inducing a small step in a random direction. The dispersal range from the walk is limited, but the walk provides key steps to either exit the sporangium or to reorient and refold. Jumps occur when the spores suddenly thrust themselves after being tightly folded. They result in a very efficient dispersal: even spores jumping from the ground can catch the wind again, whereas non-jumping spores stay on the ground. The understanding of these movements, which are solely driven by humidity variations, conveys biomimetic inspiration for a new class of self-propelled objects. PMID:24026816

  14. Jumping the Alligators in the Ditch.

    ERIC Educational Resources Information Center

    Barber, Rims

    Poor black young people in rural Mississippi contemplate their schooling with the same feelings as their friends who dare to jump the local ditches filled with alligators: the odds are against escaping the alligators, and the advantages of getting to the far side are not very apparent. Living in conditions of extreme poverty, these young people…

  15. Jumping Genes: The Transposable DNAs of Bacteria.

    ERIC Educational Resources Information Center

    Berg, Claire M.; Berg, Douglas E.

    1984-01-01

    Transposons are transposable elements that carry genes for antibiotic resistance. Provides background information on the structure and organization of these "jumping genes" in bacteria. Also describes the use of transposons in tagging genes and lists pertinent references and resource materials. (DH)

  16. Safety assessment of jumps in ski racing.

    PubMed

    Schindelwig, K; Reichl, W; Kaps, P; Mössner, M; Nachbauer, W

    2015-12-01

    The influence of important parameters on the flight trajectory for jumps in downhill World Cup races was investigated. To quantify the impact injury risk at landing, the parameter equivalent landing height (ELH) was introduced, which considered a variable slope inclination during the landing movement. Altogether, 145 runs at four different jumps in World Cup races and trainings were recorded and analyzed. A simulation model was developed to predict the flight phase of the skier. Drag and lift areas were selected by parameter identification to fit the simulation trajectory to the two-dimensional data from the video analysis. The maximum values of the ELH which can be absorbed with muscle force was taken from the study of Minetti et al. for elite female and male ski racers. A sensitivity analysis based on the four jumps showed that ELH is mainly influenced by takeoff angle, takeoff speed, and the steepness of the landing surface. With the help of the developed simulation software, it should be possible to predict the ELH for jumps in advance. In case of an excessive ELH, improvements can be made by changing the takeoff inclination or the approach speed. PMID:25123506

  17. Jumping-droplet electrostatic energy harvesting

    NASA Astrophysics Data System (ADS)

    Miljkovic, Nenad; Preston, Daniel J.; Enright, Ryan; Wang, Evelyn N.

    2014-07-01

    Micro- and nanoscale wetting phenomena have been an active area of research due to its potential for improving engineered system performance involving phase change. With the recent advancements in micro/nanofabrication techniques, structured surfaces can now be designed to allow condensing coalesced droplets to spontaneously jump off the surface due to the conversion of excess surface energy into kinetic energy. In addition to being removed at micrometric length scales (˜10 μm), jumping water droplets also attain a positive electrostatic charge (˜10-100 fC) from the hydrophobic coating/condensate interaction. In this work, we take advantage of this droplet charging to demonstrate jumping-droplet electrostatic energy harvesting. The charged droplets jump between superhydrophobic copper oxide and hydrophilic copper surfaces to create an electrostatic potential and generate power during formation of atmospheric dew. We demonstrated power densities of ˜15 pW/cm2, which, in the near term, can be improved to ˜1 μW/cm2. This work demonstrates a surface engineered platform that promises to be low cost and scalable for atmospheric energy harvesting and electric power generation.

  18. Understanding the Physics of Bungee Jumping

    ERIC Educational Resources Information Center

    Heck, Andre; Uylings, Peter; Kedzierska, Ewa

    2010-01-01

    Changing mass phenomena like the motion of a falling chain, the behaviour of a falling elastic bar or spring, and the motion of a bungee jumper surprise many a physicist. In this article we discuss the first phase of bungee jumping, when the bungee jumper falls, but the bungee rope is still slack. In instructional material this phase is often…

  19. Fast Regulation of Vertical Squat Jump during Push-Off in Skilled Jumpers.

    PubMed

    Fargier, Patrick; Massarelli, Raphael; Rabahi, Tahar; Gemignani, Angelo; Fargier, Emile

    2016-01-01

    The height of a maximum Vertical Squat Jump (VSJ) reflects the useful power produced by a jumper during the push-off phase. In turn this partly depends on the coordination of the jumper's segmental rotations at each instant. The physical system constituted by the jumper has been shown to be very sensitive to perturbations and furthermore the movement is realized in a very short time (ca. 300 ms), compared to the timing of known feedback loops. However, the dynamics of the segmental coordination and its efficiency in relation to energetics at each instant of the push-off phase still remained to be clarified. Their study was the main purpose of the present research. Eight young adult volunteers (males) performed maximal VSJ. They were skilled in jumping according to their sport activities (track and field or volleyball). A video analysis on the kinematics of the jump determined the influence of the jumpers' segments rotation on the vertical velocity and acceleration of the body mass center (MC). The efficiency in the production of useful power at the jumpers' MC level, by the rotation of the segments, was measured in consequence. The results showed a great variability in the segmental movements of the eight jumpers, but homogeneity in the overall evolution of these movements with three consecutive types of coordination in the second part of the push-off (lasting roughly 0.16 s). Further analyses gave insights on the regulation of the push-off, suggesting that very fast regulation(s) of the VSJ may be supported by: (a) the adaptation of the motor cerebral programming to the jumper's physical characteristics; (b) the control of the initial posture; and PMID:27486404

  20. Fast Regulation of Vertical Squat Jump during Push-Off in Skilled Jumpers

    PubMed Central

    Fargier, Patrick; Massarelli, Raphael; Rabahi, Tahar; Gemignani, Angelo; Fargier, Emile

    2016-01-01

    The height of a maximum Vertical Squat Jump (VSJ) reflects the useful power produced by a jumper during the push-off phase. In turn this partly depends on the coordination of the jumper's segmental rotations at each instant. The physical system constituted by the jumper has been shown to be very sensitive to perturbations and furthermore the movement is realized in a very short time (ca. 300 ms), compared to the timing of known feedback loops. However, the dynamics of the segmental coordination and its efficiency in relation to energetics at each instant of the push-off phase still remained to be clarified. Their study was the main purpose of the present research. Eight young adult volunteers (males) performed maximal VSJ. They were skilled in jumping according to their sport activities (track and field or volleyball). A video analysis on the kinematics of the jump determined the influence of the jumpers' segments rotation on the vertical velocity and acceleration of the body mass center (MC). The efficiency in the production of useful power at the jumpers' MC level, by the rotation of the segments, was measured in consequence. The results showed a great variability in the segmental movements of the eight jumpers, but homogeneity in the overall evolution of these movements with three consecutive types of coordination in the second part of the push-off (lasting roughly 0.16 s). Further analyses gave insights on the regulation of the push-off, suggesting that very fast regulation(s) of the VSJ may be supported by: (a) the adaptation of the motor cerebral programming to the jumper's physical characteristics; (b) the control of the initial posture; and (c) the jumper's perception of the position of his MC relative to the ground reaction force, during push-off, to reduce energetic losses. PMID:27486404

  1. Problems with mitigation translocation of herpetofauna.

    PubMed

    Sullivan, Brian K; Nowak, Erika M; Kwiatkowski, Matthew A

    2015-02-01

    Mitigation translocation of nuisance animals is a commonly used management practice aimed at resolution of human-animal conflict by removal and release of an individual animal. Long considered a reasonable undertaking, especially by the general public, it is now known that translocated subjects are negatively affected by the practice. Mitigation translocation is typically undertaken with individual adult organisms and has a much lower success rate than the more widely practiced conservation translocation of threatened and endangered species. Nonetheless, the public and many conservation practitioners believe that because population-level conservation translocations have been successful that mitigation translocation can be satisfactorily applied to a wide variety of human-wildlife conflict situations. We reviewed mitigation translocations of reptiles, including our own work with 3 long-lived species (Gila monsters [Heloderma suspectum], Sonoran desert tortoises [Gopherus morafkai], and western diamond-backed rattlesnakes [Crotalus atrox]). Overall, mitigation translocation had a low success rate when judged either by effects on individuals (in all studies reviewed they exhibited increased movement or increased mortality) or by the success of the resolution of the human-animal conflict (translocated individuals often returned to the capture site). Careful planning and identification of knowledge gaps are critical to increasing success rates in mitigation translocations in the face of increasing pressure to find solutions for species threatened by diverse anthropogenic factors, including climate change and exurban and energy development. PMID:25040040

  2. Kinematic, Dynamic and EMG Analysis of Drop Jumps in Female Elite Triple Jump Athletes.

    PubMed

    Čoh, Milan; Matjačić, Zlatko; Peharec, Stanislav; Bačić, Petar; Rausavjević, Nikola; Maćkala, Krzysztof

    2015-07-01

    The purpose of the study was a biodynamic analysis of the kinematic, dynamic and EMG parameters of two types of drop jumps (heights of 25 cm and 45 cm). The sample of measured subjects included four female elite triple jump athletes, with their best results varying from 13.33 to 15.06 meters. The kinematic and dynamic parameters were calculated with the use of a bipedal tensiometric force plate, which was synchronized with nine CCD cameras. A 16-channel electromyography (BTS Pocket, Myolab) was used to analyze the EMG activation of the following muscles: m. erector spinae, m. gluteus, m. rectus femoris, m. vastus medialis, m. vastus lateralis, m. biceps femoris, m. soleus and m. gastrocnemius medialis. In the drop jump from a 25 cm height, the measured subjects achieved the following results: height of jump 43.37 ± 5.39 cm and ground reaction force 2770 ± 411 N. In comparison, results for the drop jump from a 45 cm height were: height of jump 45.22 ± 4.65 cm and ground reaction force 2947 ± 366 N. Vertical velocity of the take-off in the 25 cm drop jump was 2.77 ± 0.19 ms(-1) and in the 45 cm drop jump it was 2.86 ± 0.15 ms(-1). Observation of the EMG activation revealed the proximal to distal principle of muscle activation at work in both types of drop jumps. In the first phase of the concentric phase the most active muscles were m. gluteus maximus and m. rectus femoris. The greatest activity of m. gastrocnemius medialis and m. soleus was noticed in the last third of the take-off action. Significantly high EMG activation of m. vastus medialis and m. vastus lateralis was already shown in the flight phase prior to the feet making contact with the ground. PMID:26434025

  3. Autoregulating Jump Performance to Induce Functional Overreaching.

    PubMed

    Claudino, João G; Cronin, John B; Mezêncio, Bruno; Pinho, João P; Pereira, Conrado; Mochizuki, Luis; Amadio, Alberto C; Serrão, Julio C

    2016-08-01

    Claudino, JG, Cronin, JB, Mezêncio, B, Pinho, JP, Pereira, C, Mochizuki, L, Amadio, AC, and Serrão, JC. Autoregulating jump performance to induce functional overreaching. J Strength Cond Res 30(8): 2242-2249, 2016-The purpose of this study was to determine whether autoregulating jump performance using the minimal individual difference (MID) associated with countermovement jump (CMJ) height could be used to regulate and monitor a training phase that elicited functional overreaching and tapering in team sport athletes. The participants were familiarized with the jump and then the CMJ height reliability was quantified to determine the MID. Countermovement jump height was assessed in the pretesting session (T0), at the end of 4 weeks of intensified training (T1), and after 2 weeks of tapering (T2). Eighteen national level U17 male futsal players were randomly allocated into the regulated group (RG; n = 9) and the control group (CG; n = 9). The RG performed 6 weeks of training with the training load regulated by mean height of CMJ with MID, whereas the CG performed the preplanned training. The differences between groups and across time points were compared by a 2-way analysis of variance. In the RG, the MID loading was increased in weeks 3 and 4 (8.2 and 14.5%, respectively; p < 0.001) compared with the preplanned loading of the CG during the overreaching phase. In the jump results, the RG significantly (p ≤ 0.05) reduced CMJ height during T1 (effect size [ES] = -0.31; 95% confidence interval [CI]: -0.58 to -0.02); however, there were no significant changes in the CG jump height at T1 and T2. At T2, the RG significantly increased CMJ height above baseline (ES = 0.30; 95% CI: 0.09 to 0.51). Researchers and practitioners could use this autoregulating method to regulate and monitor training load to achieve functional overreaching in youth futsal players. PMID:26808857

  4. Jumping mechanisms and strategies in moths (Lepidoptera).

    PubMed

    Burrows, Malcolm; Dorosenko, Marina

    2015-06-01

    To test whether jumping launches moths into the air, take-off by 58 species, ranging in mass from 0.1 to 220 mg, was captured in videos at 1000 frames s(-1). Three strategies for jumping were identified. First, rapid movements of both middle and hind legs provided propulsion while the wings remained closed. Second, middle and hind legs again provided propulsion but the wings now opened and flapped after take-off. Third, wing and leg movements both began before take-off and led to an earlier transition to powered flight. The middle and hind legs were of similar lengths and were between 10 and 130% longer than the front legs. The rapid depression of the trochantera and extension of the middle tibiae began some 3 ms before similar movements of the hind legs, but their tarsi lost contact with the ground before take-off. Acceleration times ranged from 10 ms in the lightest moths to 25 ms in the heaviest ones. Peak take-off velocities varied from 0.6 to 0.9 m s(-1) in all moths, with the fastest jump achieving a velocity of 1.2 m s(-1). The energy required to generate the fastest jumps was 1.1 µJ in lighter moths but rose to 62.1 µJ in heavier ones. Mean accelerations ranged from 26 to 90 m s(-2) and a maximum force of 9 G: was experienced. The highest power output was within the capability of normal muscle so that jumps were powered by direct contractions of muscles without catapult mechanisms or energy storage. PMID:25883381

  5. Hormonal responses in strenuous jumping effort.

    PubMed

    Bosco, C; Tihanyl, J; Rivalta, L; Parlato, G; Tranquilli, C; Pulvirenti, G; Foti, C; Viru, M; Viru, A

    1996-02-01

    In order to test the possibility for rapid responses of blood hormone levels in short-term supramaximal exercises, serum concentrations of corticotropin (ACTH), cortisol (C), total testosterone (tT), free testosterone (fT), growth hormone (GH), thyrotropin (TSH), free thyroxine (fT4), free triiodothyronine (fT3), prolactin (PRL), insulin-like growth factor (IGF-I), and sex hormone-binding globulin (SHBG) were determined by RIA procedures in blood samples obtained before and immediately after a 60-s period of consecutive vertical jumps (Bosco test). The study subjects were 16 Italian professional soccer players. Immediately after exercise, significant increases (p < 0.05) were found in the concentrations of ACTH (by 39%), C (by 14%), TSH (by 20%), fT3 (by 28%), fT4 (by 30%), tT (by 12%), fT (by 13%), and SHBG (by 21%). Significant changes were not detected in the blood levels of GH, IGF-I and PRL. Most pronounced testosterone responses were typical for persons of high jumping performance (the increase of serum tT correlated with average power output, r = 0.61 and jumping height, r = 0.66). The larger the drop in power output during 60-s jumping, the higher was the thyroid response: the difference in jumping height between the first and last 15-s period correlated with increases in TSH (r = 0.52) and in fT4, (r = 0.55). In conclusion, the obtained results indicate that in intense exercise, causing the rapid development of fatigue, rapid increases in serum levels of hormones of the pituitary-adrenocortical, pituitary-gonadal and pituitary-thyroid systems occur. PMID:8743723

  6. Deconvoluting chain heterogeneity from driven translocation through a nanopore

    NASA Astrophysics Data System (ADS)

    Adhikari, Ramesh; Bhattacharya, Aniket

    2015-02-01

    We study translocation dynamics of a driven compressible semi-flexible chain consisting of alternate blocks of stiff (S) and flexible (F) segments of size m and n, respectively, for different chain length N in two dimensions (2D). The free parameters in the model are the bending rigidity κb which controls the three-body interaction term, the elastic constant kF in the FENE (bond) potential between successive monomers, as well as the segmental lengths m and n and the repeat unit p (N=m_pn_p) and the solvent viscosity γ. We demonstrate that due to the change in entropic barrier and the inhomogeneous viscous drag on the chain backbone a variety of scenarios are possible, amply manifested in the waiting time distribution of the translocating chain. This information can be deconvoluted to extract the mechanical properties of the chain at various length scales and thus can be used to nanopore based methods to probe bio-molecules, such as DNA, RNA and proteins.

  7. Surface-adsorption-induced polymer translocation through a nanopore: Effects of the adsorption strength and the surface corrugation

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaoyu; Yu, Wancheng; Luo, Kaifu

    2015-08-01

    The surface corrugation plays an important role in single polymer diffusion on attractive surfaces. However, its effect on dynamics of surface adsorption-induced polymer translocation through a nanopore is not clear. Using three-dimensional Langevin dynamics simulations, we investigate the dynamics of a flexible polymer chain translocation through a nanopore induced by the selective adsorption of translocated segments onto the trans side of the membrane. The translocation probability Pt r a n s increases monotonically, while the mean translocation time τ has a minimum as a function of the adsorption strength ɛ , which are explained from the perspective of the effective driving force for the translocation. With the surface being smoother, τ as well as the scaling exponent α of τ with the chain length N decreases. Finally, we show that the distributions of the translocation time are non-Gaussian even for strong adsorption at a moderate surface corrugation. A nearly Gaussian distribution of the translocation time is observed only for the smoothest surface we studied.

  8. Translocation (Y;12) in lipoma.

    PubMed

    Liang, Cher-Wei; Mariño-Enríquez, Adrian; Johannessen, Catherine; Hornick, Jason L; Dal Cin, Paola

    2011-01-01

    Lipomas are the most common benign mesenchymal neoplasm in adults, and have been extensively characterized at the cytogenetic level. Chromosomal aberrations have been observed in the majority of lipomas, two-thirds of which involve chromosomal region 12q14.3. To date, structural rearrangements have been reported affecting every chromosome except chromosome Y. Here we report a case of a lipoma that shows a novel apparently balanced translocation involving chromosomes Y and 12. Fluorescence in situ hybridization using a break-apart HMGA2 in-house probe set detected a single signal on the normal chromosome 12 but not on either the derivative chromosome Y or 12, indicating a cryptic loss of 12q14.3, where HMGA2 is mapped. Immunohistochemical studies, however, revealed overexpression of HMGA2 with nuclear expression in the majority of tumor cells, whereas MDM2 and CDK4 were negative. The overexpression of HMGA2 may be caused by a cryptic chromosomal aberration affecting either the cytogenetically unaltered HMGA2 allele or HMGA2 regulators elsewhere. The current case broadens our knowledge about the translocation partners of HMGA2 in lipomas and highlights the biological complexity in regulating HMGA2 expression. PMID:21356192

  9. Entropy jump across an inviscid shock wave

    NASA Technical Reports Server (NTRS)

    Salas, Manuel D.; Iollo, Angelo

    1995-01-01

    The shock jump conditions for the Euler equations in their primitive form are derived by using generalized functions. The shock profiles for specific volume, speed, and pressure are shown to be the same, however density has a different shock profile. Careful study of the equations that govern the entropy shows that the inviscid entropy profile has a local maximum within the shock layer. We demonstrate that because of this phenomenon, the entropy, propagation equation cannot be used as a conservation law.

  10. In Situ Temperature Jump Dynamic Nuclear Polarization

    PubMed Central

    Joo, Chan-Gyu; Casey, Andrew; Turner, Christopher J.; Griffin, Robert G.

    2009-01-01

    Dynamic nuclear polarization is combined with temperature jump methods to develop a new 2D 13C- 13C NMR experiment that yields a factor or 100-170 increase insensitivity. The polaization step is performed at ∼100 K and the sample is subsequently melted with a 10.6 mm laser pulse to yield a sample with highly polarized 13C spins. 13C detected 2D 13C- 13C spectroscopy is performed in the usual manner. PMID:18942782

  11. Haloarchaeal Protein Translocation via the Twin Arginine Translocation Pathway

    SciTech Connect

    Pohlschroder Mechthild

    2009-02-03

    Protein transport across hydrophobic membranes that partition cellular compartments is essential in all cells. The twin arginine translocation (Tat) pathway transports proteins across the prokaryotic cytoplasmic membranes. Distinct from the universally conserved Sec pathway, which secretes unfolded proteins, the Tat machinery is unique in that it secretes proteins in a folded conformation, making it an attractive pathway for the transport and secretion of heterologously expressed proteins that are Sec-incompatible. During the past 7 years, the DOE-supported project has focused on the characterization of the diversity of bacterial and archaeal Tat substrates as well as on the characterization of the Tat pathway of a model archaeon, Haloferax volcanii, a member of the haloarchaea. We have demonstrated that H. volcanii uses this pathway to transport most of its secretome.

  12. Field measurements in unwadeable natural hydraulic jumps

    NASA Astrophysics Data System (ADS)

    Valle, B.; Pasternack, G.

    2003-04-01

    Recent research in fluvial geomorphology has emphasized the development and application of digital terrain models to better understand process-form relations. However, field measurements in mountain channels have largely been restricted to low velocity or ephemeral flow conditions. To address this problem, a new high-resolution mechanical surveying system was developed at UC Davis and used to measure the 3D bed and water surface topographies of an unwadeable plunging hydraulic jump in the Cache Creek basin, CA. Labeled as the River Truss, the system is capable of making high-resolution form and process measurements over a 30 to 115 m2 area. Bed and water surface DTMs were derived from the field data using AutoCAD. River Truss precision was assessed by DTM differencing the hydraulic jump bed surface topography with a DTM developed from tacheometric survey at low base flows. Bed surface DTMs indicate significant spatial complexity of the underlying bed step in the supercritical flow region and significant downstream bed scour. Water surface DTMs indicate 3D complexity of the plunging flow surface and divergence from 1D free-fall theory. Further study will emphasize the development and deployment of process-based instrumentation such that the complex turbulent air-water flow dynamics associated with natural hydraulic jumps may be better understood. Also, a second generation River Truss that has a larger coverage area and automated data collection has been designed and is now being built.

  13. Phosphorus Compounds in Translocating Phloem

    PubMed Central

    Bieleski, R. L.

    1969-01-01

    Phosphate-32P was introduced into a turnip leaf, and 3 hr later, the vascular bundles were stripped from the petiole and their phosphate ester pattern was studied. The pattern did not alter along their length and was like that of other tissues. Pumpkin leaves were painted with phosphate-32P; and later, the petioles were cut, the sieve tube exudates were collected and their phosphate ester patterns were studied. Exudates collected after 10 min had a high proportion of their 32P present in Pi and nucleoside triphosphates, while exudates collected after long translocation times (4-22 hr) had a lower proportion in these, and a higher proportion in hexose monophosphates and UDP glucose. In general, the ester patterns were like those of other tissues. The results indicate that sieve tubes are metabolically active, and that Pi is the primary form in which phosphorus moves in the phloem. Images PMID:16657091

  14. DNA translocation through graphene nanopores.

    PubMed

    Merchant, Christopher A; Healy, Ken; Wanunu, Meni; Ray, Vishva; Peterman, Neil; Bartel, John; Fischbein, Michael D; Venta, Kimberly; Luo, Zhengtang; Johnson, A T Charlie; Drndić, Marija

    2010-08-11

    We report on DNA translocations through nanopores created in graphene membranes. Devices consist of 1-5 nm thick graphene membranes with electron-beam sculpted nanopores from 5 to 10 nm in diameter. Due to the thin nature of the graphene membranes, we observe larger blocked currents than for traditional solid-state nanopores. However, ionic current noise levels are several orders of magnitude larger than those for silicon nitride nanopores. These fluctuations are reduced with the atomic-layer deposition of 5 nm of titanium dioxide over the device. Unlike traditional solid-state nanopore materials that are insulating, graphene is an excellent electrical conductor. Use of graphene as a membrane material opens the door to a new class of nanopore devices in which electronic sensing and control are performed directly at the pore. PMID:20698604

  15. Determinants of the abilities to jump higher and shorten the contact time in a running 1-legged vertical jump in basketball.

    PubMed

    Miura, Ken; Yamamoto, Masayoshi; Tamaki, Hiroyuki; Zushi, Koji

    2010-01-01

    This study was conducted to obtain useful information for developing training techniques for the running 1-legged vertical jump in basketball (lay-up shot jump). The ability to perform the lay-up shot jump and various basic jumps was measured by testing 19 male basketball players. The basic jumps consisted of the 1-legged repeated rebound jump, the 2-legged repeated rebound jump, and the countermovement jump. Jumping height, contact time, and jumping index (jumping height/contact time) were measured and calculated using a contact mat/computer system that recorded the contact and air times. The jumping index indicates power. No significant correlation existed between the jumping height and contact time of the lay-up shot jump, the 2 components of the lay-up shot jump index. As a result, jumping height and contact time were found to be mutually independent abilities. The relationships in contact time between the lay-up shot jump to the 1-legged repeated rebound jump and the 2-legged repeated rebound jump were correlated on the same significance levels (p < 0.05). A significant correlation for jumping height existed between the 1-legged repeated rebound jump and the lay-up shot jump (p < 0.05), although none existed for jumping height between the lay-up shot jump and both the 2-legged repeated rebound jump and countermovement jump. The lay-up shot index correlated more strongly to the 1-legged repeated rebound jump index (p < 0.01) when compared to the 2-legged repeated rebound jump index (p < 0.05). These results suggest that the 1-legged repeated rebound jump is effective in improving both contact time and jumping height in the lay-up shot jump. PMID:19996782

  16. Costs and benefits of larval jumping behaviour of Bathyplectes anurus.

    PubMed

    Saeki, Yoriko; Tani, Soichiro; Fukuda, Katsuto; Iwase, Shun-ichiro; Sugawara, Yuma; Tuda, Midori; Takagi, Masami

    2016-02-01

    Bathyplectes anurus, a parasitoid of the alfalfa weevils, forms a cocoon in the late larval stage and exhibits jumping behaviour. Adaptive significance and costs of the cocoon jumping have not been thoroughly studied. We hypothesised that jumping has the fitness benefits of enabling habitat selection by avoiding unfavourable environments. We conducted laboratory experiments, which demonstrated that jumping frequencies increased in the presence of light, with greater magnitudes of temperature increase and at lower relative humidity. In addition, when B. anurus individuals were allowed to freely jump in an arena with a light gradient, more cocoons were found in the shady area, suggesting microhabitat selection. In a field experiment, mortality of cocoons placed in the sun was significantly higher than for cocoons placed in the shade. B. anurus cocoons respond to environmental stress by jumping, resulting in habitat selection. In the presence of potential predators (ants), jumping frequencies were higher than in the control (no ant) arenas, though jumping frequencies decreased after direct contact with the predators. Body mass of B. anurus cocoons induced to jump significantly decreased over time than cocoons that did not jump, suggesting a cost to jumping. We discuss the benefits and costs of jumping behaviour and potential evolutionary advantages of this peculiar trait, which is present in a limited number of species. PMID:26687130

  17. Costs and benefits of larval jumping behaviour of Bathyplectes anurus

    NASA Astrophysics Data System (ADS)

    Saeki, Yoriko; Tani, Soichiro; Fukuda, Katsuto; Iwase, Shun-ichiro; Sugawara, Yuma; Tuda, Midori; Takagi, Masami

    2016-02-01

    Bathyplectes anurus, a parasitoid of the alfalfa weevils, forms a cocoon in the late larval stage and exhibits jumping behaviour. Adaptive significance and costs of the cocoon jumping have not been thoroughly studied. We hypothesised that jumping has the fitness benefits of enabling habitat selection by avoiding unfavourable environments. We conducted laboratory experiments, which demonstrated that jumping frequencies increased in the presence of light, with greater magnitudes of temperature increase and at lower relative humidity. In addition, when B. anurus individuals were allowed to freely jump in an arena with a light gradient, more cocoons were found in the shady area, suggesting microhabitat selection. In a field experiment, mortality of cocoons placed in the sun was significantly higher than for cocoons placed in the shade. B. anurus cocoons respond to environmental stress by jumping, resulting in habitat selection. In the presence of potential predators (ants), jumping frequencies were higher than in the control (no ant) arenas, though jumping frequencies decreased after direct contact with the predators. Body mass of B. anurus cocoons induced to jump significantly decreased over time than cocoons that did not jump, suggesting a cost to jumping. We discuss the benefits and costs of jumping behaviour and potential evolutionary advantages of this peculiar trait, which is present in a limited number of species.

  18. Vertical Jump and Leg Power Norms for Young Adults

    ERIC Educational Resources Information Center

    Patterson, David D.; Peterson, D. Fred

    2004-01-01

    Medical students and their spouses (N = 724) served as participants to create norm-referenced vertical jump values for active, healthy people ages 21-30. All tests were conducted and measured by the same individual during a campus fitness evaluation using a Vertec[TM] apparatus. Jump height was measured to the nearest 0.5 in. Mean jump height was…

  19. An efficient interpolation technique for jump proposals in reversible-jump Markov chain Monte Carlo calculations.

    PubMed

    Farr, W M; Mandel, I; Stevens, D

    2015-06-01

    Selection among alternative theoretical models given an observed dataset is an important challenge in many areas of physics and astronomy. Reversible-jump Markov chain Monte Carlo (RJMCMC) is an extremely powerful technique for performing Bayesian model selection, but it suffers from a fundamental difficulty and it requires jumps between model parameter spaces, but cannot efficiently explore both parameter spaces at once. Thus, a naive jump between parameter spaces is unlikely to be accepted in the Markov chain Monte Carlo (MCMC) algorithm and convergence is correspondingly slow. Here, we demonstrate an interpolation technique that uses samples from single-model MCMCs to propose intermodel jumps from an approximation to the single-model posterior of the target parameter space. The interpolation technique, based on a kD-tree data structure, is adaptive and efficient in modest dimensionality. We show that our technique leads to improved convergence over naive jumps in an RJMCMC, and compare it to other proposals in the literature to improve the convergence of RJMCMCs. We also demonstrate the use of the same interpolation technique as a way to construct efficient 'global' proposal distributions for single-model MCMCs without prior knowledge of the structure of the posterior distribution, and discuss improvements that permit the method to be used in higher dimensional spaces efficiently. PMID:26543580

  20. Force generation and temperature-jump and length-jump tension transients in muscle fibers.

    PubMed

    Davis, J S; Rodgers, M E

    1995-05-01

    Muscle tension rises with increasing temperature. The kinetics that govern the tension rise of maximally Ca(2+)-activated, skinned rabbit psoas fibers over a temperature range of 0-30 degrees C was characterized in laser temperature-jump experiments. The kinetic response is simple and can be readily interpreted in terms of a basic three-step mechanism of contraction, which includes a temperature-sensitive rapid preequilibrium(a) linked to a temperature-insensitive rate-limiting step and followed by a temperature-sensitive tension-generating step. These data and mechanism are compared and contrasted with the more complex length-jump Huxley-Simmons phases in which all states that generate tension or bear tension are perturbed. The rate of the Huxley-Simmons phase 4 is temperature sensitive at low temperatures but plateaus at high temperatures, indicating a change in rate-limiting step from a temperature-sensitive (phase 4a) to a temperature-insensitive reaction (phase 4b); the latter appears to correlate with the slow, temperature-insensitive temperature-jump relaxation. Phase 3 is absent in the temperature-jump, which excludes it from tension generation. We confirm that de novo tension generation occurs as an order-disorder transition during phase 2slow and the equivalent, temperature-sensitive temperature-jump relaxation. PMID:7612845

  1. An efficient interpolation technique for jump proposals in reversible-jump Markov chain Monte Carlo calculations

    PubMed Central

    Farr, W. M.; Mandel, I.; Stevens, D.

    2015-01-01

    Selection among alternative theoretical models given an observed dataset is an important challenge in many areas of physics and astronomy. Reversible-jump Markov chain Monte Carlo (RJMCMC) is an extremely powerful technique for performing Bayesian model selection, but it suffers from a fundamental difficulty and it requires jumps between model parameter spaces, but cannot efficiently explore both parameter spaces at once. Thus, a naive jump between parameter spaces is unlikely to be accepted in the Markov chain Monte Carlo (MCMC) algorithm and convergence is correspondingly slow. Here, we demonstrate an interpolation technique that uses samples from single-model MCMCs to propose intermodel jumps from an approximation to the single-model posterior of the target parameter space. The interpolation technique, based on a kD-tree data structure, is adaptive and efficient in modest dimensionality. We show that our technique leads to improved convergence over naive jumps in an RJMCMC, and compare it to other proposals in the literature to improve the convergence of RJMCMCs. We also demonstrate the use of the same interpolation technique as a way to construct efficient ‘global’ proposal distributions for single-model MCMCs without prior knowledge of the structure of the posterior distribution, and discuss improvements that permit the method to be used in higher dimensional spaces efficiently. PMID:26543580

  2. Deriving appropriate boundary conditions, and accelerating position-jump simulations, of diffusion using non-local jumping.

    PubMed

    Taylor, P R; Baker, R E; Yates, C A

    2014-01-01

    In this paper we explore lattice-based position-jump models of diffusion, and the implications of introducing non-local jumping; particles can jump to a range of nearby boxes rather than only to their nearest neighbours. We begin by deriving conditions for equivalence with traditional local jumping models in the continuum limit. We then generalize a previously postulated implementation of the Robin boundary condition for a non-local process of arbitrary maximum jump length, and present a novel implementation of flux boundary conditions, again generalized for a non-local process of arbitrary maximum jump length. In both these cases we validate our results using stochastic simulation. We then proceed to consider two variations on the basic diffusion model: a hybrid local/non-local scheme suitable for models involving sharp concentration gradients, and the implementation of biased jumping. In all cases we show that non-local jumping can deliver substantial time savings for stochastic simulations. PMID:25514045

  3. Deriving appropriate boundary conditions, and accelerating position-jump simulations, of diffusion using non-local jumping

    NASA Astrophysics Data System (ADS)

    Taylor, P. R.; Baker, R. E.; Yates, C. A.

    2015-02-01

    In this paper we explore lattice-based position-jump models of diffusion, and the implications of introducing non-local jumping; particles can jump to a range of nearby boxes rather than only to their nearest neighbours. We begin by deriving conditions for equivalence with traditional local jumping models in the continuum limit. We then generalize a previously postulated implementation of the Robin boundary condition for a non-local process of arbitrary maximum jump length, and present a novel implementation of flux boundary conditions, again generalized for a non-local process of arbitrary maximum jump length. In both these cases we validate our results using stochastic simulation. We then proceed to consider two variations on the basic diffusion model: a hybrid local/non-local scheme suitable for models involving sharp concentration gradients, and the implementation of biased jumping. In all cases we show that non-local jumping can deliver substantial time savings for stochastic simulations.

  4. Finding Jumps in Otherwise Smooth Curves: Identifying Critical Events in Political Processes

    PubMed Central

    Ratkovic, Marc T.

    2010-01-01

    Many social processes are stable and smooth in general, with discrete jumps. We develop a sequential segmentation spline method that can identify both the location and the number of discontinuities in a series of observations with a time component, while fitting a smooth spline between jumps, using a modified Bayesian Information Criterion statistic as a stopping rule. We explore the method in a large-n, unbalanced panel setting with George W. Bush’s approval data, a small-n time series with median DW-NOMINATE scores for each Congress over time, and a series of simulations. We compare the method to several extant smoothers, and the method performs favorably in terms of visual inspection, residual properties, and event detection. Finally, we discuss extensions of the method. PMID:20721311

  5. Association between traditional standing vertical jumps and a soccer-specific vertical jump.

    PubMed

    Requena, Bernardo; Garcia, Inmaculada; Requena, Francisco; Bressel, Eadric; Saez-Saez de Villarreal, Eduardo; Cronin, John

    2014-01-01

    The present study aimed to determine the relationships between a soccer-specific vertical jump (ssVJ) test, that included common elements of a soccer VJ (e.g. run-up and intention to head), and three traditional VJ tests using elite soccer players. A secondary purpose of this study was to determine the reliability of the VJs used in the analysis. A randomised order and counterbalanced design was used to assess the relationships between these VJs [countermovement jump (CMJ), drop jump for height (DJh), drop jump for maximum height and minimum ground contact time (DJh/t) and the ssVJ]. Take-off velocity, contact time and flight time were the dependent variables of interest and compared between jumps. Intra-class correlation coefficient (ICC) and coefficient of variation (CV) were used as measures of inter-session reliability. All VJ tests were found to have high ICCs (0.89-0.99) and acceptable within-subject CVs (<7.5%). All the ssVJ dependent variables were not significantly related (r<0.44) with similar variables from the CMJ and DJh tests and only moderately related (r=~0.49) with the DJh/t test variables. In addition, the DJh/t variables were not significantly correlated (r<0.47) with DJh and CMJ test variables. In conclusion, it would seem that the proposed ssVJ test and CMJ or DJh tests assess different leg qualities and thought should be given before using them interchangeably to assess or develop the same performance measures (i.e. velocity at take-off or jump height). PMID:24444234

  6. Simple jumping process with memory: Transport equation and diffusion

    NASA Astrophysics Data System (ADS)

    Kamińska, A.; Srokowski, T.

    2004-06-01

    We present a stochastic jumping process, defined in terms of jump-size probability density and jumping rate, which is a generalization of the well-known kangaroo process. The definition takes into account two process values: after and before the jump. Therefore, the process is able to preserve memory about its previous values. It possesses a simple stationary limit. Its master equation is interpreted as the kinetic equation with variable collision rate. The process can be easily applied to model systems which relax to distributions other than Maxwellian. The case of a constant jumping rate corresponds to the diffusion process, either normal or ballistic.

  7. Jumping performance of planthoppers (Hemiptera, Issidae).

    PubMed

    Burrows, Malcolm

    2009-09-01

    The structure of the hind limbs and the kinematics of their movements that propel jumping in planthopper insects (Hemiptera, Auchenorrhyncha, Fulgoroidea, Issidae) were analysed. The propulsion for a jump was delivered by rapid movements of the hind legs that both move in the same plane beneath the body and parallel to its longitudinal axis, as revealed in high-speed sequences of images captured at rates up to 7500 images s(-1). The first and key movement was the depression of both trochantera about their coxae, powered by large depressor muscles in the thorax, accompanied by rapid extension of the tibiae about their femora. The initial movements of the two trochantera of the hind legs were synchronised to within 0.03 ms. The hind legs are only 20% longer than the front and middle legs, represent 65% of the body length, and have a ratio of 1.8 relative to the cube root of the body mass. The two hind coxae have a different structure to those in frog- and leafhoppers. They are fused at the mid-line, covered ventrally by transparent cuticle, and each is fixed laterally to a part of the internal skeleton called the pleural arch that extends to the articulation of a hind wing. A small and pointed, ventral coxal protrusion covered in microtrichia engages with a raised, smooth, white patch on a dorsal femur when a hind leg is levated (cocked) in preparation for a jump. In the best jumps by a male Issus, the body was accelerated in 0.8 ms to a take-off velocity of 5.5 m s(-1), was subjected to a force of 719 g and was displaced a horizontal distance of 1.1 m. This performance required an energy output of 303 microJ, a power output of 388 mW and exerted a force of 141 mN, or more than 700 times its body mass. This performance implies that a catapult mechanism must be used, and that Issus ranks alongside the froghopper Philaenus as one of the best insect jumpers. PMID:19684220

  8. Katabatic jumps over Martian polar terrains

    NASA Astrophysics Data System (ADS)

    Spiga, Aymeric; Smith, Isaac; Holt, Jack

    2015-04-01

    Recent observational and modeling studies have shed light on the key role of mesoscale phenomena in driving the Martian climate and giving rise to remarkable signatures in the temperature, wind, pressure, and aerosol fields of the Martian atmosphere. At the mesoscale, Mars appears as an intense and exotic counterpart to the Earth, mainly as a result of pronounced diurnal and regional contrasts of surface temperature, and the much thinner atmosphere. While observations of clear-cut katabatic events are difficult on Earth, except over vast ice sheets, those intense downslope circulations are widespread on Mars owing to near-surface radiative cooling and uneven topography. Their intensity and regularity can be witnessed through numerous aeolian signatures on the surface, and distinctive thermal signatures in the steepest craters and volcanoes. Several observations (radar observations, frost streaks, spectral analysis of ices, ...) concur to show that aeolian processes play a key role in glacial processes in Martian polar regions over geological timescales. A spectacular manifestation of this resides in elongated clouds that forms at the bottom of polar spiral troughs, which dominates the polar landscape both in the North and South. An analogy with the terrestrial "wall-of-snow" over e.g. Antarctica slopes or coastlines posits that those clouds are caused by local katabatic jumps, also named Loewe phenomena, which can be deemed similar to first order to hydraulic jumps in open channel flow. With mesoscale modeling in polar regions using 5 nested domains operating a model downscaling from horizontal resolutions of about twenty kilometers to 200 meters, we were able 1. to predict the near-surface wind structure over the whole Martian polar caps, with interactions between katabatic acceleration, Coriolis deflection, transient phenomena, and thermally-forced circulations by the ice / bare soil contrast and 2. to show that katabatic jumps form at the bottom of polar troughs

  9. Biomechanical analysis of the jump shot in basketball.

    PubMed

    Struzik, Artur; Pietraszewski, Bogdan; Zawadzki, Jerzy

    2014-09-29

    Basketball players usually score points during the game using the jump shot. For this reason, the jump shot is considered to be the most important element of technique in basketball and requires a high level of performance. The aim of this study was to compare the biomechanical characteristics of the lower limbs during a jump shot without the ball and a countermovement jump without an arm swing. The differences between variables provide information about the potential that an athlete can utilise during a game when performing a jump shot. The study was conducted among 20 second-league basketball players by means of a Kistler force plate and the BTS SMART system for motion analysis. The variables measured included the take-off time, mean power, peak power, relative mean power, jump height, maximum landing force and calculated impact ratio. Surprisingly, more advantageous variables were found for the jump shot. This finding suggests a very high performance level in the jump shot in the studied group and a maximum utilisation of their motor abilities. Both types of jumps were characterised by high mean and peak power values and average heights. The high forces at landing, which result in considerable impact ratios, may have prompted the studied group to land softly. Use of the countermovement jump without an arm swing is recommended to assess and predict the progression of player's jumping ability. PMID:25414741

  10. Asymmetric seafloor spreading and short ridge jumps in the Australian-Antarctic discordance

    NASA Astrophysics Data System (ADS)

    Marks, Karen M.; Stock, Joann M.

    1995-08-01

    The crenulated geometry of the Southeast Indian ridge within the Australian-Antarctic discordance is formed by numerous spreading ridge segments that are offset, alternately to the north and south, by transform faults. Suggested causes for these offsets, which largely developed since ~ 20 Ma, include asymmetric seafloor spreading, ridge jumps, and propagating rifts that have transferred seafloor from one flank of the spreading ridge to the other. Each of these processes has operated at different times in different locations of the discordance; here we document an instance where a small (~ 20 km), young (< 0.2 Ma), southward ridge jump has contributed to the observed asymmetry. When aeromagnetic anomalies from the Project Investigator-1 survey are superposed on gravity anomalies computed from Geosat GM and ERM data, we find that in segment B4 of the discordance (between 125° and 126° E), the roughly east-west-trending gravity low, correlated with the axial valley, is 20 25 km south of the ridge axis position inferred from the center of magnetic anomaly 1. Elsewhere in the discordance, the inferred locations of the ridge axis from magnetics and gravity are in excellent agreement. Ship track data confirm these observations: portions of Moana Wave track crossing the ridge in B4 show that a topographic valley correlated with the gravity anomaly low lies south of the center of magnetic anomaly 1; while other ship track data that cross the spreading ridge in segments B3 and B5 demonstrate good agreement between the axial valley, the gravity anomaly low, and the central magnetic anomaly. Based on these observations, we speculate that the ridge axis in B4 has recently jumped to the south, from a ridge location closer to the center of the young normally magnetized crust, to that of the gravity anomaly low. The position of the gravity low essentially at the edge of normally magnetized crust requires a very recent (< 0.2 Ma) arrival of the ridge in this new location. Because

  11. Understanding the physics of bungee jumping

    NASA Astrophysics Data System (ADS)

    Heck, André; Uylings, Peter; Kędzierska, Ewa

    2010-01-01

    Changing mass phenomena like the motion of a falling chain, the behaviour of a falling elastic bar or spring, and the motion of a bungee jumper surprise many a physicist. In this article we discuss the first phase of bungee jumping, when the bungee jumper falls, but the bungee rope is still slack. In instructional material this phase is often considered a free fall, but when the mass of the bungee rope is taken into account, the bungee jumper reaches acceleration greater than g. This result is contrary to the usual experience with free falling objects and therefore hard to believe for many a person, even an experienced physicist. It is often a starting point for heated discussions about the quality of the experiments and the physics knowledge of the experimentalist, or it may even prompt complaints about the quality of current physics education. But experiments do reveal the truth and students can do them supported by information and communication technology (ICT) tools. We report on a research project done by secondary school students and use their work to discuss how measurements with sensors, video analysis of self-recorded high-speed video clips and computer modelling allow study of the physics of bungee jumping.

  12. A jumping cylinder on an inclined plane

    NASA Astrophysics Data System (ADS)

    Gómez, R. W.; Hernández-Gómez, J. J.; Marquina, V.

    2012-09-01

    The problem of a cylinder of mass m and radius r, with its centre of mass out of the cylinder’s axis, rolling on an inclined plane that makes an angle α with respect to the horizontal, is analysed. The equation of motion is partially solved to obtain the site where the cylinder loses contact with the inclined plane (jumps). Several simplifications are made: the analysed system consists of an homogeneous disc with a one-dimensional straight line mass parallel to the disc axis at a distance y < r of the centre of the cylinder. To compare our results with experimental data, we use a styrofoam cylinder to which a long brass rod is embedded parallel to the disc axis at a distance y < r from it, so the centre of mass lies at a distance d from the centre of the cylinder. Then the disc rolls without slipping on a long wooden ramp inclined at 15°, 30° and 45° with respect to the horizontal. To determine the jumping site, the movements are recorded with a high-speed video camera (Casio EX ZR100) at 240 and 480 frames per second. The experimental results agree well with the theoretical predictions.

  13. A jumping cylinder in an incline

    NASA Astrophysics Data System (ADS)

    Gomez, Raul W.; Hernandez, Jorge; Marquina, Vivianne

    2012-02-01

    The problem of a cylinder of mass m and radius r, with its center of mass out of the cylinder axis, rolling in an incline that makes an angle α respect to the horizontal is analyzed. The equation of motion is solved to obtain the site where the cylinder loses contact with the incline (jumps). Several simplifications are made: the analyzed system consists of an homogeneous disc with a one dimensional straight line of mass parallel to the disc axis at a distance d < r of the center of the cylinder. To compare our results with experimental data, we use a Styrofoam cylinder of radius r = 10.0 ± 0.05 cm, high h = 5.55 ± 0.05 cm and a mass m1 = 24.45 ± 0.05 g, to which a 9.50 ± 0.01 mm diameter and 5.10 ± 0.001 cm long brass road of mass m2 = 30.75 ± 0.05 g was imbibed parallel to the disc axis at a distance of 5.40 ± 0.05 cm from it. Then the disc rolls on a 3.20 m long wooden ramp inclined at 30 and 45 respect to the horizontal. To determine the jumping site, the movements were recorded with a high-speed video camera (Casio EX ZR100) at 400 frames per second. The experimental results agree well with the theoretical predictions.

  14. CAPTURE OF TROJANS BY JUMPING JUPITER

    SciTech Connect

    Nesvorny, David; Vokrouhlicky, David; Morbidelli, Alessandro

    2013-05-01

    Jupiter Trojans are thought to be survivors of a much larger population of planetesimals that existed in the planetary region when planets formed. They can provide important constraints on the mass and properties of the planetesimal disk, and its dispersal during planet migration. Here, we tested a possibility that the Trojans were captured during the early dynamical instability among the outer planets (aka the Nice model), when the semimajor axis of Jupiter was changing as a result of scattering encounters with an ice giant. The capture occurs in this model when Jupiter's orbit and its Lagrange points become radially displaced in a scattering event and fall into a region populated by planetesimals (that previously evolved from their natal transplanetary disk to {approx}5 AU during the instability). Our numerical simulations of the new capture model, hereafter jump capture, satisfactorily reproduce the orbital distribution of the Trojans and their total mass. The jump capture is potentially capable of explaining the observed asymmetry in the number of leading and trailing Trojans. We find that the capture probability is (6-8) Multiplication-Sign 10{sup -7} for each particle in the original transplanetary disk, implying that the disk contained (3-4) Multiplication-Sign 10{sup 7} planetesimals with absolute magnitude H < 9 (corresponding to diameter D = 80 km for a 7% albedo). The disk mass inferred from this work, M{sub disk} {approx} 14-28 M{sub Earth}, is consistent with the mass deduced from recent dynamical simulations of the planetary instability.

  15. Validation and influence of anthropometric and kinematic models of obese teenagers in vertical jump performance and mechanical internal energy expenditure.

    PubMed

    Achard de Leluardière, F; Hajri, L N; Lacouture, P; Duboy, J; Frelut, M L; Peres, G

    2006-02-01

    There may be concerns about the validity of kinetic models when studying locomotion in obese subjects (OS). The aim of the present study was to improve and validate a relevant representation of obese subject from four kinetic models. Fourteen teenagers with severe primary obesity (BMI = 40 +/- 5.2 kg/m(2)), were studied during jumping. The jumps were filmed by six cameras (synchronized, 50 Hz), associated with a force-plate (1,000 Hz). All the tested models were valid; the linear mechanical analysis of the jumps gave similar results (p > 0.05); but there were significantly different segment inertias when considering the subjects' abdomen (p < 0.01), which was associated with a significantly higher mechanical internal energy expenditure (p < 0.01) than that estimated from Dempster's and Hanavan's model, by about 40 and 30%. The validation of a modelling specifically for obese subjects will enable a better understanding of their locomotion. PMID:16399510

  16. Potential for Non-Contact ACL Injury Between Step-Close-Jump and Hop-Jump Tasks

    PubMed Central

    Wang, Li-I; Gu, Chin-Yi; Chen, Wei-Ling; Chang, Mu-San

    2010-01-01

    This study aimed to compare the kinematics and kinetics during the landing of hop-jump and step-close-jump movements in order to provide further inferring that the potential risk of ACL injuries. Eleven elite male volleyball players were recruited to perform hop-jump and step-close-jump tasks. Lower extremity kinematics and ground reaction forces during landing in stop-jump tasks were recorded. Lower extremity kinetics was calculated by using an inverse dynamic process. Step-close-jump tasks demonstrated smaller peak proximal tibia anterior shear forces during the landing phase. In step-close-jump tasks, increasing hip joint angular velocity during initial foot-ground contact decreased peak posterior ground reaction force during the landing phase, which theoretically could reduce the risk of ACL injury. Key points The different landing techniques required for these two stop-jump tasks do not necessarily affect the jump height. Hop-jump decreased the hip joint angular velocity at initial foot contact with ground, which could lead to an increasing peak posterior GRF during the landing phase. Hop-jump decreased hip and knee joint angular flexion displacement during the landing, which could increase the peak vertical loading rate during the landing phase. PMID:24149397

  17. Jumping robots: a biomimetic solution to locomotion across rough terrain.

    PubMed

    Armour, Rhodri; Paskins, Keith; Bowyer, Adrian; Vincent, Julian; Megill, William; Bomphrey, Richard

    2007-09-01

    This paper introduces jumping robots as a means to traverse rough terrain; such terrain can pose problems for traditional wheeled, tracked and legged designs. The diversity of jumping mechanisms found in nature is explored to support the theory that jumping is a desirable ability for a robot locomotion system to incorporate, and then the size-related constraints are determined from first principles. A series of existing jumping robots are presented and their performance summarized. The authors present two new biologically inspired jumping robots, Jollbot and Glumper, both of which incorporate additional locomotion techniques of rolling and gliding respectively. Jollbot consists of metal hoop springs forming a 300 mm diameter sphere, and when jumping it raises its centre of gravity by 0.22 m and clears a height of 0.18 m. Glumper is of octahedral shape, with four 'legs' that each comprise two 500 mm lengths of CFRP tube articulating around torsion spring 'knees'. It is able to raise its centre of gravity by 1.60 m and clears a height of 1.17 m. The jumping performance of the jumping robot designs presented is discussed and compared against some specialized jumping animals. Specific power output is thought to be the performance-limiting factor for a jumping robot, which requires the maximization of the amount of energy that can be stored together with a minimization of mass. It is demonstrated that this can be achieved through optimization and careful materials selection. PMID:17848786

  18. Intersubunit movement is required for ribosomal translocation

    PubMed Central

    Horan, Lucas H.; Noller, Harry F.

    2007-01-01

    Translocation of tRNA and mRNA during protein synthesis is believed to be coupled to structural changes in the ribosome. The “ratchet model,” based on cryo-EM reconstructions of ribosome complexes, invokes relative movement of the 30S and 50S ribosomal subunits in this process; however, evidence that directly demonstrates a requirement for intersubunit movement during translocation is lacking. To address this problem, we created an intersubunit disulfide cross-link to restrict potential movement. The cross-linked ribosomes were unable to carry out polypeptide synthesis; this inhibition was completely reversed upon reduction of the disulfide bridge. In vitro assays showed that the cross-linked ribosomes were specifically blocked in elongation factor G-dependent translocation. These findings show that intersubunit movement is required for ribosomal translocation, accounting for the universal two-subunit architecture of ribosomes. PMID:17360328

  19. Diagnostic studies of ensemble forecast "jumps"

    NASA Astrophysics Data System (ADS)

    Magnusson, Linus; Hewson, Tim; Ferranti, Laura; Rodwell, Mark

    2016-04-01

    During 2015 we saw exceptional consistency in successive seasonal forecasts produced at ECMWF, for the winter period 2015/16, right across the globe. This winter was characterised by a well-predicted and unusually strong El Nino, and some have ascribed the consistency to that. For most of December this consistency was mirrored in the (separate) ECMWF monthly forecast system, which correctly predicted anomalously strong (mild) zonal flow, over the North Atlantic and western Eurasia, even in forecasts for weeks 3 and 4. In monthly forecasts in general these weeks are often devoid of strong signals. However in late December and early January strong signals, even in week 2, proved to be incorrect, most notably over the North Atlantic and Eurasian sectors. Indeed on at least two occasions the outcome was beyond the ensemble forecast range over Scandinavia. In one of these conditions flipped from extreme mild to extreme cold as a high latitude block developed. Temperature prediction is very important to many customers, notably those dealing with renewable energy, because cold weather causes increased demand but also tends to coincide with reduced wind power production. So understandably jumps can cause consternation amongst some customer groups, and are very difficult to handle operationally. This presentation will discuss the results of initial diagnostic investigations into what caused the "ensemble jumps", particularly at the week two lead, though reference will also be made to a related shorter range (day 3) jump that was important for flooding over the UK. Initial results suggest that an inability of the ECMWF model to correctly represent convective outbreaks over North America (that for winter-time were quite extreme) played an important role. Significantly, during this period, an unusually large amount of upper air data over North America was rejected or ascribed low weight. These results bear similarities to previous diagnostic studies at ECMWF, wherein major

  20. What Drives the Translocation of Proteins?

    NASA Astrophysics Data System (ADS)

    Simon, Sanford M.; Peskin, Charles S.; Oster, George F.

    1992-05-01

    We propose that protein translocation across membranes is driven by biased random thermal motion. This "Brownian ratchet" mechanism depends on chemical asymmetries between the cis and trans sides of the membrane. Several mechanisms could contribute to rectifying the thermal motion of the protein, such as binding and dissociation of chaperonins to the translocating chain, chain coiling induced by pH and/or ionic gradients, glycosylation, and disulfide bond formation. This helps explain the robustness and promiscuity of these transport systems.

  1. Stress and translocation: alterations in the stress physiology of translocated birds.

    PubMed

    Dickens, Molly J; Delehanty, David J; Romero, L Michael

    2009-06-01

    Translocation and reintroduction have become major conservation actions in attempts to create self-sustaining wild populations of threatened species. However, avian translocations have a high failure rate and causes for failure are poorly understood. While 'stress' is often cited as an important factor in translocation failure, empirical evidence of physiological stress is lacking. Here we show that experimental translocation leads to changes in the physiological stress response in chukar partridge, Alectoris chukar. We found that capture alone significantly decreased the acute glucocorticoid (corticosterone, CORT) response, but adding exposure to captivity and transport further altered the stress response axis (the hypothalamic-pituitary-adrenal axis) as evident from a decreased sensitivity of the negative feedback system. Animals that were exposed to the entire translocation procedure, in addition to the reduced acute stress response and disrupted negative feedback, had significantly lower baseline CORT concentrations and significantly reduced body weight. These data indicate that translocation alters stress physiology and that chronic stress is potentially a major factor in translocation failure. Under current practices, the restoration of threatened species through translocation may unwittingly depend on the success of chronically stressed individuals. This conclusion emphasizes the need for understanding and alleviating translocation-induced chronic stress in order to use most effectively this important conservation tool. PMID:19324794

  2. Stress and translocation: alterations in the stress physiology of translocated birds

    PubMed Central

    Dickens, Molly J.; Delehanty, David J.; Romero, L. Michael

    2009-01-01

    Translocation and reintroduction have become major conservation actions in attempts to create self-sustaining wild populations of threatened species. However, avian translocations have a high failure rate and causes for failure are poorly understood. While ‘stress’ is often cited as an important factor in translocation failure, empirical evidence of physiological stress is lacking. Here we show that experimental translocation leads to changes in the physiological stress response in chukar partridge, Alectoris chukar. We found that capture alone significantly decreased the acute glucocorticoid (corticosterone, CORT) response, but adding exposure to captivity and transport further altered the stress response axis (the hypothalamic–pituitary–adrenal axis) as evident from a decreased sensitivity of the negative feedback system. Animals that were exposed to the entire translocation procedure, in addition to the reduced acute stress response and disrupted negative feedback, had significantly lower baseline CORT concentrations and significantly reduced body weight. These data indicate that translocation alters stress physiology and that chronic stress is potentially a major factor in translocation failure. Under current practices, the restoration of threatened species through translocation may unwittingly depend on the success of chronically stressed individuals. This conclusion emphasizes the need for understanding and alleviating translocation-induced chronic stress in order to use most effectively this important conservation tool. PMID:19324794

  3. Ratcheting up protein translocation with anthrax toxin

    PubMed Central

    Feld, Geoffrey K; Brown, Michael J; Krantz, Bryan A

    2012-01-01

    Energy-consuming nanomachines catalyze the directed movement of biopolymers in the cell. They are found both dissolved in the aqueous cytosol as well as embedded in lipid bilayers. Inquiries into the molecular mechanism of nanomachine-catalyzed biopolymer transport have revealed that these machines are equipped with molecular parts, including adjustable clamps, levers, and adaptors, which interact favorably with substrate polypeptides. Biological nanomachines that catalyze protein transport, known as translocases, often require that their substrate proteins unfold before translocation. An unstructured protein chain is likely entropically challenging to bind, push, or pull in a directional manner, especially in a way that produces an unfolding force. A number of ingenious solutions to this problem are now evident in the anthrax toxin system, a model used to study protein translocation. Here we highlight molecular ratchets and current research on anthrax toxin translocation. A picture is emerging of proton-gradient-driven anthrax toxin translocation, and its associated ratchet mechanism likely applies broadly to other systems. We suggest a cyclical thermodynamic order-to-disorder mechanism (akin to a heat-engine cycle) is central to underlying protein translocation: peptide substrates nonspecifically bind to molecular clamps, which possess adjustable affinities; polypeptide substrates compress into helical structures; these clamps undergo proton-gated switching; and the substrate subsequently expands regaining its unfolded state conformational entropy upon translocation. PMID:22374876

  4. Defining chromosomal translocation risks in cancer.

    PubMed

    Hogenbirk, Marc A; Heideman, Marinus R; de Rink, Iris; Velds, Arno; Kerkhoven, Ron M; Wessels, Lodewyk F A; Jacobs, Heinz

    2016-06-28

    Chromosomal translocations are a hallmark of cancer. Unraveling the molecular mechanism of these rare genetic events requires a clear distinction between correlative and causative risk-determinants, where technical and analytical issues can be excluded. To meet this goal, we performed in-depth analyses of publicly available genome-wide datasets. In contrast to several recent reports, we demonstrate that chromosomal translocation risk is causally unrelated to promoter stalling (Spt5), transcriptional activity, or off-targeting activity of the activation-induced cytidine deaminase. Rather, an open chromatin configuration, which is not promoter-specific, explained the elevated translocation risk of promoter regions. Furthermore, the fact that gene size directly correlates with the translocation risk in mice and human cancers further demonstrated the general irrelevance of promoter-specific activities. Interestingly, a subset of translocations observed in cancer patients likely initiates from double-strand breaks induced by an access-independent process. Together, these unexpected and novel insights are fundamental in understanding the origin of chromosome translocations and, consequently, cancer. PMID:27303044

  5. Defining chromosomal translocation risks in cancer

    PubMed Central

    Hogenbirk, Marc A.; Heideman, Marinus R.; de Rink, Iris; Velds, Arno; Kerkhoven, Ron M.; Wessels, Lodewyk F. A.; Jacobs, Heinz

    2016-01-01

    Chromosomal translocations are a hallmark of cancer. Unraveling the molecular mechanism of these rare genetic events requires a clear distinction between correlative and causative risk-determinants, where technical and analytical issues can be excluded. To meet this goal, we performed in-depth analyses of publicly available genome-wide datasets. In contrast to several recent reports, we demonstrate that chromosomal translocation risk is causally unrelated to promoter stalling (Spt5), transcriptional activity, or off-targeting activity of the activation-induced cytidine deaminase. Rather, an open chromatin configuration, which is not promoter-specific, explained the elevated translocation risk of promoter regions. Furthermore, the fact that gene size directly correlates with the translocation risk in mice and human cancers further demonstrated the general irrelevance of promoter-specific activities. Interestingly, a subset of translocations observed in cancer patients likely initiates from double-strand breaks induced by an access-independent process. Together, these unexpected and novel insights are fundamental in understanding the origin of chromosome translocations and, consequently, cancer. PMID:27303044

  6. Translocation of DNA across bacterial membranes.

    PubMed Central

    Dreiseikelmann, B

    1994-01-01

    DNA translocation across bacterial membranes occurs during the biological processes of infection by bacteriophages, conjugative DNA transfer of plasmids, T-DNA transfer, and genetic transformation. The mechanism of DNA translocation in these systems is not fully understood, but during the last few years extensive data about genes and gene products involved in the translocation processes have accumulated. One reason for the increasing interest in this topic is the discussion about horizontal gene transfer and transkingdom sex. Analyses of genes and gene products involved in DNA transfer suggest that DNA is transferred through a protein channel spanning the bacterial envelope. No common model exists for DNA translocation during phage infection. Perhaps various mechanisms are necessary as a result of the different morphologies of bacteriophages. The DNA translocation processes during conjugation, T-DNA transfer, and transformation are more consistent and may even be compared to the excretion of some proteins. On the basis of analogies and homologies between the proteins involved in DNA translocation and protein secretion, a common basic model for these processes is presented. PMID:7968916

  7. Generator estimation of Markov jump processes

    NASA Astrophysics Data System (ADS)

    Metzner, P.; Dittmer, E.; Jahnke, T.; Schütte, Ch.

    2007-11-01

    Estimating the generator of a continuous-time Markov jump process based on incomplete data is a problem which arises in various applications ranging from machine learning to molecular dynamics. Several methods have been devised for this purpose: a quadratic programming approach (cf. [D.T. Crommelin, E. Vanden-Eijnden, Fitting timeseries by continuous-time Markov chains: a quadratic programming approach, J. Comp. Phys. 217 (2006) 782-805]), a resolvent method (cf. [T. Müller, Modellierung von Proteinevolution, PhD thesis, Heidelberg, 2001]), and various implementations of an expectation-maximization algorithm ([S. Asmussen, O. Nerman, M. Olsson, Fitting phase-type distributions via the EM algorithm, Scand. J. Stat. 23 (1996) 419-441; I. Holmes, G.M. Rubin, An expectation maximization algorithm for training hidden substitution models, J. Mol. Biol. 317 (2002) 753-764; U. Nodelman, C.R. Shelton, D. Koller, Expectation maximization and complex duration distributions for continuous time Bayesian networks, in: Proceedings of the twenty-first conference on uncertainty in AI (UAI), 2005, pp. 421-430; M. Bladt, M. Sørensen, Statistical inference for discretely observed Markov jump processes, J.R. Statist. Soc. B 67 (2005) 395-410]). Some of these methods, however, seem to be known only in a particular research community, and have later been reinvented in a different context. The purpose of this paper is to compile a catalogue of existing approaches, to compare the strengths and weaknesses, and to test their performance in a series of numerical examples. These examples include carefully chosen model problems and an application to a time series from molecular dynamics.

  8. Neurons controlling jumping in froghopper insects.

    PubMed

    Bräunig, Peter; Burrows, Malcolm

    2008-03-01

    The neurons innervating muscles that deliver the enormous power enabling froghopper insects to excel at jumping were revealed by backfilling the nerves from those muscles. The huge trochanteral depressor muscle (M133) of a hind leg consists of four parts. The two largest parts (M133b,c) occupy most of the metathorax and are innervated by the same two motor neurons that have small, laterally placed somata in the metathoracic ganglion and axons in nerve N3C(2). They are also supplied by three dorsal unpaired median (DUM) neurons with the largest diameter somata in the central nervous system. A small metathoracic part of the muscle (M133d) is supplied by two motor neurons with lateral somata and by common inhibitory motor neuron CI(1), all with axons in nerve N3C(3) The motor neuron with the larger soma has a thick primary neurite that projects across the midline of the ganglion so that its branches overlap those of its symmetrical counterpart,innervating the same muscle of the other hind leg. The fourth coxal part of the muscle (M133a) is innervated by two motor neurons (one with a ventral and the other with a dorsal and lateral soma), by CI(1), and by a DUM neuron with a small soma. All have axons in nerve N5A. The two trochanteral levator muscles of a hind leg are contained within the coxa and are separately innervated by nerves N3B and N4, respectively. The properties of the different motor neurons are discussed in the context of the neural patterns that generate jumping. PMID:18095320

  9. Predator Mimicry: Metalmark Moths Mimic Their Jumping Spider Predators

    PubMed Central

    Rota, Jadranka; Wagner, David L.

    2006-01-01

    Cases of mimicry provide many of the nature's most convincing examples of natural selection. Here we report evidence for a case of predator mimicry in which metalmark moths in the genus Brenthia mimic jumping spiders, one of their predators. In controlled trials, Brenthia had higher survival rates than other similarly sized moths in the presence of jumping spiders and jumping spiders responded to Brenthia with territorial displays, indicating that Brenthia were sometimes mistaken for jumping spiders, and not recognized as prey. Our experimental results and a review of wing patterns of other insects indicate that jumping spider mimicry is more widespread than heretofore appreciated, and that jumping spiders are probably an important selective pressure shaping the evolution of diurnal insects that perch on vegetation. PMID:17183674

  10. Evaluation of Metabolic Stress between Jumping at Different Cadences on the Digi-Jump Machine

    PubMed Central

    LYONS, THOMAS S.; NAVALTA, JAMES W.; CALLAHAN, ZACHARY J.

    2010-01-01

    The American College of Sports Medicine (ACSM) recommends that healthy adults achieve a minimum of thirty minutes of moderate intensity aerobic exercise five days per week. While cycling, walking, and jogging are commonly observed methods of achieving these recommendations, another option may be repetitive jumping. The purpose of this study was to examine the metabolic responses between repetitive jumping at a cadence of 120 jumps per minute (JPMs) vs. 100 JPMs when utilizing the Digi-Jump machine. Twenty-eight subjects completed two jumping trials, one at 120 JPMs and one at 100 JPMs. Subjects jumped until volitional exhaustion, or for a maximum of fifteen minutes. Oxygen uptake (VO2), heart rate (HR), respiratory exchange ratio (RER), and rating of perceived exertion (RPE) were assessed each minute of each exercise trial. RPE was differentiated, in that subjects reported perceived exertion of their total body, their upper-leg, and their lower leg. Results of this study indicated that there was no significant difference between the two trials for VO2, HR, or total body RPE. Differences were reported between trials for peak and average RER, with the 120 JPM trial eliciting a lower RER for both (peak: 1.08 ± .087 vs. 1.17 ± .1 p=.000; average: .99 ± .076 vs. 1.04 ± .098 p=.002), peak upper leg RPE (120: 15.29 ± 3.89 vs. 100: 16.75 ± 2.52 p=.022), and average lower leg RPE (120: 15.04 ± 2.55 vs. 100: 13.94 ± 2.02 p=.019). Also, there was a significant difference in exercise duration between the trials, with subjects able to exercise longer during the 120 JPM trial (12.4 ± 3.42 mins vs. 9.68 ± 4.31 mins p=.000). These data indicate that while the physiological stress may not be different between the two trials as indicated by VO2 and HR, the 120 JPM trial appears less strenuous as evidenced by RER values and by subjects’ ability to exercise longer at that cadence. PMID:27182351

  11. Pricing turbo warrants under mixed-exponential jump diffusion model

    NASA Astrophysics Data System (ADS)

    Yu, Jianfeng; Xu, Weidong

    2016-06-01

    Turbo warrant is a special type of barrier options in which the rebate is calculated as another exotic option. In this paper, using Laplace transforms we obtain the valuation of turbo warrant under the mixed-exponential jump diffusion model, which is able to approximate any jump size distribution. The numerical Laplace inversion examples verify that the analytical solutions are accurate. The results of simulation confirm the argument that jump risk should not be ignored in the valuation of turbo warrants.

  12. Hydrodynamics of jumping for prey capture in Archer fish

    NASA Astrophysics Data System (ADS)

    Techet, A. H.; Shih, A. M.

    2010-11-01

    The prey capture behavior by jumping Archer fish (Toxotes microlepisis) was investigated using high speed imaging and particle imaging velocimetry (PIV). Archer fish are renowned for their ability to spit jets of water at insects and also to jump out of the water to capture their prey. Our investigations reveal that the fish typically fail to reach their prey by jumping when the bait is placed at a height above 3.5 body lengths. After jumping and failing, the fish do not typically jump again, only spit. For our experiments bait was placed between 0.5 and 3.5 body lengths (BL) above the free surface, within reach of jumping, and thus the fish rarely spit unless they missed first by jumping. It is observed that the fish typically position their bodies under the bait with a slight angle, hover momentarily, snap in their pectoral fins, and then flap their tail in an "S-start"-type maneuver with a fixed number of cycles, which increases as a function of bait height. High speed imaging, including time-resolved PIV, was used to capture the kinematics of the jumping behavior and compare the fluid impulse generated during the fast start, jump maneuver with the total change in momentum of the fish body. Maximum acceleration was observed in the early stages of the jump maneuver and was often on the order of 5 to 15 times gravity. Correlations between the maximum energy, power in, number of tail beats, jump height and overall jumping kinematics will be discussed.

  13. Automatic Segmentation of Mechanically Inhomogeneous Tissues Based on Deformation Gradient Jump.

    PubMed

    Witzenburg, Colleen M; Dhume, Rohit Y; Lake, Spencer P; Barocas, Victor H

    2016-01-01

    Variations in properties, active behavior, injury, scarring, and/or disease can all cause a tissue's mechanical behavior to be heterogeneous. Advances in imaging technology allow for accurate full-field displacement tracking of both in vitro and in vivo deformation from an applied load. While detailed strain fields provide some insight into tissue behavior, material properties are usually determined by fitting stress-strain behavior with a constitutive equation. However, the determination of the mechanical behavior of heterogeneous soft tissue requires a spatially varying constitutive equation (i.e., one in which the material parameters vary with position). We present an approach that computationally dissects the sample domain into many homogeneous subdomains, wherein subdomain boundaries are formed by applying a betweenness based graphical analysis to the deformation gradient field to identify locations with large discontinuities. This novel partitioning technique successfully determined the shape, size and location of regions with locally similar material properties for: (1) a series of simulated soft tissue samples prescribed with both abrupt and gradual changes in anisotropy strength, prescribed fiber alignment, stiffness, and nonlinearity, (2) tissue analogs (PDMS and collagen gels) which were tested biaxially and speckle tracked (3) and soft tissues which exhibited a natural variation in properties (cadaveric supraspinatus tendon), a pathologic variation in properties (thoracic aorta containing transmural plaque), and active behavior (contracting cardiac sheet). The routine enables the dissection of samples computationally rather than physically, allowing for the study of small tissues specimens with unknown and irregular inhomogeneity. PMID:26168433

  14. Segment alignment control system

    NASA Technical Reports Server (NTRS)

    Aubrun, JEAN-N.; Lorell, Ken R.

    1988-01-01

    The segmented primary mirror for the LDR will require a special segment alignment control system to precisely control the orientation of each of the segments so that the resulting composite reflector behaves like a monolith. The W.M. Keck Ten Meter Telescope will utilize a primary mirror made up of 36 actively controlled segments. Thus the primary mirror and its segment alignment control system are directly analogous to the LDR. The problems of controlling the segments in the face of disturbances and control/structures interaction, as analyzed for the TMT, are virtually identical to those for the LDR. The two systems are briefly compared.

  15. Relative Intensity Influences the Degree of Correspondence of Jump Squats and Push Jerks to Countermovement Jumps.

    PubMed

    Cushion, Emily J; Goodwin, Jon E; Cleather, Daniel J

    2016-05-01

    Cushion, EJ, Goodwin, JE, and Cleather, DJ. Relative intensity influences the degree of correspondence of jump squats and push jerks to countermovement jumps. J Strength Cond Res 30(5): 1255-1264, 2016-The aim of this study was to determine the mechanical similarity between push jerk (PJ) and jump squat (JS) to countermovement jump (CMJ) and further understand the effect increasing external load may have on this relationship. Eight physically trained men (age 22 ± 3; height 176 ± 7 kg; weight 83 ± 8 kg) performed an unloaded CMJ followed by JS under a range of loads (10, 25, 35, and 50% 1RM back squat) and PJ (30, 50, 65, and 75% 1RM push jerk). A portable force platform and high-speed camera both collecting at 250 Hz were used to establish joint moments and impulse during the propulsive phase of the movements. A standard inverse dynamics model was used to determine joint moment and impulse at the hip, knee, and ankle. Significant correlations (p ≤ 0.05) were shown between CMJ knee joint moment and JS knee joint moment at 25% load and PJ knee joint moment at 30 and 50% load. Significant correlations were also observed between CMJ knee joint impulse and JS knee joint impulse at 10% load and PJ knee joint moment at 30 and 65% load. Significant correlation was also observed between CMJ hip joint impulse and PJ hip joint impulse at 30% load. No significant joint × load interaction was shown as load increased for either PJ or JS. Results from the study suggest partial correspondence between PJ and JS to CMJ, where a greater mechanical similarity was observed between the PJ and CMJ. This interaction is load and joint dependent where lower relative loads showed greatest mechanical similarity. Therefore using lower relative loads when programming may provide a greater transfer of training effect. PMID:26439777

  16. Microbiology of bacterial translocation in humans

    PubMed Central

    O'Boyle, C; MacFie, J; Mitchell, C; Johnstone, D; Sagar, P; Sedman, P

    1998-01-01

    Background—Gut translocation of bacteria has been shown in both animal and human studies. Evidence from animal studies that links bacterial translocation to the development of postoperative sepsis and multiple organ failure has yet to be confirmed in humans. 
Aims—To examine the spectrum of bacteria involved in translocation in surgical patients undergoing laparotomy and to determine the relation between nodal migration of bacteria and the development of postoperative septic complications. 
Methods—Mesenteric lymph nodes (MLN), serosal scrapings, and peripheral blood from 448 surgical patients undergoing laparotomy were analysed using standard microbiological techniques. 
Results—Bacterial translocation was identified in 69 patients (15.4%). The most common organism identified was Escherichia coli (54%). Both enteric bacteria, typical of indigenous intestinal flora, and non-enteric bacteria were isolated. Postoperative septic complications developed in 104 patients (23%). Enteric organisms were responsible in 74% of patients. Forty one per cent of patients who had evidence of bacterial translocation developed sepsis compared with 14% in whom no organisms were cultured (p<0.001). Septic morbidity was more frequent when a greater diversity of bacteria resided within the MLN, but this was not statistically significant. 
Conclusion—Bacterial translocation is associated with a significant increase in the development of postoperative sepsis in surgical patients. The organisms responsible for septic morbidity are similar in spectrum to those observed in the mesenteric lymph nodes. These data strongly support the gut origin hypothesis of sepsis in humans. 

 Keywords: bacterial translocation; mesenteric lymph nodes; serosal scrapings; enteric bacteria; postoperative sepsis PMID:9505882

  17. Molecular studies of free and translocation trisomy

    SciTech Connect

    Robinson, W.P.; Bernasconi, F.; Lefort, G.

    1994-09-01

    Twenty cases of trisomy 13 were examined with molecular markers to determine the origin of the extra chromosome. Six cases had translocation trisomy: two de novo rob(13q;14q), one paternally derived rob(13q;14q), two de novo t(13q;13q), and one mosaic de novo t(13q;14q), one paternally derived rob(13q;14q), two de novo t(13q;13q), and one mosaic de novo t(13q;13q)r(13). Eighteen of nineteen informative patients were consistant with a maternal origin of the extra chromosome. Lack of a third allele at any locus in any of the three t(13q;13q) cases indicate that all were most likely isochromosomes of post-meiotic origin. In addition, two free trisomy cases were compatible with a somatic origin. Two mosaic free trisomy-13 cases, however, were both consistent with a maternal meiotic origin. The patient with a paternal inheritance of the translocation chromosome was purely coincidental. Since there is not a significantly increased risk for unbalanced offspring of a t(13;14) carrier and most trisomies are maternal in origin, this result should not be surprising; however it illustrates that one cannot infer the origin of translocation trisomy based on parental origin of the translocation. One balanced (non-trisomic) case with a non-mosaic 45,-13,-13,+t(13;13) karyotype was also investigated and was determined to be a somatic Robertsonian translocation between the maternal and paternal homologs, as has been found for all homologous Robertsonian translocations so far investigated. It is therefore also incorrect to assume in de novo translocation cases that the two involved chromosomes are even from the same parent. We cannot therefore infer anything about the origin of the chromosomes 13 and 14 involved in the two cases with de novo t(13q;14q) plus a maternally derived trisomy 13.

  18. Exploiting knowledge of jump-up and jump-down frequencies to determine the parameters of a Duffing oscillator

    NASA Astrophysics Data System (ADS)

    Ramlan, Roszaidi; Brennan, Michael J.; Kovacic, Ivana; Mace, Brian R.; Burrow, Stephen G.

    2016-08-01

    This work concerns the application of certain non-linear phenomena - jump frequencies in a base-excited Duffing oscillator - to the estimation of the parameters of the system. First, approximate analytical expressions are derived for the relationships between the jump-up and jump-down frequencies, the damping ratio and the cubic stiffness coefficient. Then, experimental results, together with the results of numerical simulations, are presented to show how knowledge of these frequencies can be exploited.

  19. Jump dynamics due to jump datum of compressible viscous Navier-Stokes flows in a bounded plane domain

    NASA Astrophysics Data System (ADS)

    Kweon, Jae Ryong

    2016-09-01

    In this paper, when the initial density has a jump across an interior curve in a bounded domain, we show unique existence, piecewise regularity and jump discontinuity dynamics for the density and the velocity vector governed by the Navier-Stokes equations of compressible viscous barotropic flows. A critical difficulty is in controlling the gradient of the pressure across the jump curve. This is resolved by constructing a vector function associated with the pressure jump value on the convecting curve and extending it to the whole domain.

  20. Bilateral asymmetries in max effort single-leg vertical jumps.

    PubMed

    Stephens, Thomas M; Lawson, Brooke R; Reiser, Raoul F

    2005-01-01

    While asymmetries in the lower extremity during jumping may have implications during rehabilitation, it is not clear if healthy subjects should be expected to jump equivalently on each leg. Therefore, the goal of this study was to determine if asymmetries exist in maximal effort single-leg vertical jumps. After obtaining university-approved informed consent, 13 men and 12 women with competitive volleyball playing experience and no injuries of the lower-extremity that would predispose them to asymmetries participated. After thorough warm-up, five maximal effort vertical jumps with countermovement were performed on each leg (random order) with ground reaction forces and lower extremity kinematics recorded. The best three jumps from each leg were analyzed, assigning the leg with the highest jump height average as the dominant side. Asymmetry was assessed by determining statistical significance in the dominant versus non-dominant sides (p < 0.05). A significant interaction existed between side and gender for thigh length and peak vertical ground reaction force. Women had a significantly shorter thigh and men a greater peak vertical ground reaction force on their dominant side. All other parameters were assessed as whole group. Jumps were significantly greater off the dominant leg (2.8 cm on average). No other differences between sides were observed. Significant differences in magnitude (p < 0.05) existed between the men and women in jump height, several anthropometric parameters, minimum ankle and hip angles, and vertical ground reaction forces (peak and average). In conclusion, though a person may jump slightly higher on one leg relative to the other, and women may jump slightly differently than men, the magnitude of the difference should be relatively small and due to the multi-factorial nature of jump performance, individual parameters related to performance may not be consistently different. PMID:15850125

  1. Hofmeister effect of anions on calcium translocation by sarcoplasmic reticulum Ca2+-ATPase

    NASA Astrophysics Data System (ADS)

    Tadini-Buoninsegni, Francesco; Moncelli, Maria Rosa; Peruzzi, Niccolò; Ninham, Barry W.; Dei, Luigi; Nostro, Pierandrea Lo

    2015-10-01

    The occurrence of Hofmeister (specific ion) effects in various membrane-related physiological processes is well documented. For example the effect of anions on the transport activity of the ion pump Na+, K+-ATPase has been investigated. Here we report on specific anion effects on the ATP-dependent Ca2+ translocation by the sarcoplasmic reticulum Ca2+-ATPase (SERCA). Current measurements following ATP concentration jumps on SERCA-containing vesicles adsorbed on solid supported membranes were carried out in the presence of different potassium salts. We found that monovalent anions strongly interfere with ATP-induced Ca2+ translocation by SERCA, according to their increasing chaotropicity in the Hofmeister series. On the contrary, a significant increase in Ca2+ translocation was observed in the presence of sulphate. We suggest that the anions can affect the conformational transition between the phosphorylated intermediates E1P and E2P of the SERCA cycle. In particular, the stabilization of the E1P conformation by chaotropic anions seems to be related to their adsorption at the enzyme/water and/or at the membrane/water interface, while the more kosmotropic species affect SERCA conformation and functionality by modifying the hydration layers of the enzyme.

  2. Biomechanical analysis of squat jump and countermovement jump from varying starting positions.

    PubMed

    Mackala, Krzysztof; Stodółka, Jacek; Siemienski, Adam; Coh, Milan

    2013-10-01

    The purpose of this study was to investigate the effect of 2 strategies, defined by foot placement during the initiation of the take-off on performance in vertical jumps. The additional area of interest in this experiment was whether technique of the take-off phase might be an exploratory factor that has different electromyogram (EMG) muscle activity during squat jump (SJ) and countermovement jump (CMJ) performed starting from the standard position, with parallel foot placement, and from the experimental one, with straddle foot placement. Six well-experienced male 100-400 m sprinters, who were members of the Polish youth and senior national team (mean values: age 21.6 years, best performance: 100 m in 10.54 seconds and 400 m in 45.54 seconds), performed vertical SJ and vertical CMJ from 2 initial positions with different foot placement. To collect all selected kinematic and kinetic data, the video recording system BTS Vixta was used in conjunction with force platforms (Kistler model 9286B). The latest system for 3D motion analysis, BTS SMART, based on the passive IR reflective markers was also applied. Electromyograms of 6 lower limb muscles were collected using a Noraxon EMG device. The CMJ was on average 7 cm higher than the SJ (CMJ, 85 cm and SJ, 78 cm), which amounts to 8.97%. This was not because of the increase of center of gravity (COG) velocity at take-off because velocities of center of gravity (COG) projection were almost equal (SJ, 2.93 m·scompared with CMJ, 2.99 m·s). No significant differences of both magnitude and rate of development of the muscle torques and powers between jumps were found, but when we analyzed the problem with division into single legs (right and left) and with division into different jumps (SJ and CMJ), the differences were evident. The profiles of EMG activity of selected muscles showed some differences between SJ and CMJ. The vertical SJ and CMJ performance measurement may be of value to coaches and conditioning specialists who

  3. Stochastic resonance during a polymer translocation process.

    PubMed

    Mondal, Debasish; Muthukumar, M

    2016-04-14

    We have studied the occurrence of stochastic resonance when a flexible polymer chain undergoes a single-file translocation through a nano-pore separating two spherical cavities, under a time-periodic external driving force. The translocation of the chain is controlled by a free energy barrier determined by chain length, pore length, pore-polymer interaction, and confinement inside the donor and receiver cavities. The external driving force is characterized by a frequency and amplitude. By combining the Fokker-Planck formalism for polymer translocation and a two-state model for stochastic resonance, we have derived analytical formulas for criteria for emergence of stochastic resonance during polymer translocation. We show that no stochastic resonance is possible if the free energy barrier for polymer translocation is purely entropic in nature. The polymer chain exhibits stochastic resonance only in the presence of an energy threshold in terms of polymer-pore interactions. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly. PMID:27083746

  4. Stochastic resonance during a polymer translocation process

    NASA Astrophysics Data System (ADS)

    Mondal, Debasish; Muthukumar, M.

    2016-04-01

    We have studied the occurrence of stochastic resonance when a flexible polymer chain undergoes a single-file translocation through a nano-pore separating two spherical cavities, under a time-periodic external driving force. The translocation of the chain is controlled by a free energy barrier determined by chain length, pore length, pore-polymer interaction, and confinement inside the donor and receiver cavities. The external driving force is characterized by a frequency and amplitude. By combining the Fokker-Planck formalism for polymer translocation and a two-state model for stochastic resonance, we have derived analytical formulas for criteria for emergence of stochastic resonance during polymer translocation. We show that no stochastic resonance is possible if the free energy barrier for polymer translocation is purely entropic in nature. The polymer chain exhibits stochastic resonance only in the presence of an energy threshold in terms of polymer-pore interactions. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly.

  5. Sipunculans and segmentation

    PubMed Central

    Kristof, Alen; Brinkmann, Nora

    2009-01-01

    Comparative molecular, developmental and morphogenetic analyses show that the three major segmented animal groups—Lophotrochozoa, Ecdysozoa and Vertebrata—use a wide range of ontogenetic pathways to establish metameric body organization. Even in the life history of a single specimen, different mechanisms may act on the level of gene expression, cell proliferation, tissue differentiation and organ system formation in individual segments. Accordingly, in some polychaete annelids the first three pairs of segmental peripheral neurons arise synchronously, while the metameric commissures of the ventral nervous system form in anterior-posterior progression. Contrary to traditional belief, loss of segmentation may have occurred more often than commonly assumed, as exemplified in the sipunculans, which show remnants of segmentation in larval stages but are unsegmented as adults. The developmental plasticity and potential evolutionary lability of segmentation nourishes the controversy of a segmented bilaterian ancestor versus multiple independent evolution of segmentation in respective metazoan lineages. PMID:19513266

  6. Segmented trapped vortex cavity

    NASA Technical Reports Server (NTRS)

    Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

    2010-01-01

    An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

  7. [Bilateral segmental neurofibromatosis].

    PubMed

    Rose, I; Vakilzadeh, F

    1991-12-01

    Segmental neurofibromatosis is a rare type of neurofibromatosis. We report a case of bilateral manifestation, review the literature on this extremely uncommon variant, and discuss the possible causative mechanisms and the genetic risk of segmental neurofibromatosis. PMID:1765491

  8. Station Tour: Russian Segment

    NASA Video Gallery

    Expedition 33 Commander Suni Williams concludes her tour of the International Space Station with a visit to the Russian segment, which includes Zarya, the first segment of the station launched in 1...

  9. Motor control of landing from a countermovement jump in simulated microgravity.

    PubMed

    Gambelli, C N; Theisen, D; Willems, P A; Schepens, B

    2016-05-15

    Landing from a jump implies proper positioning of the lower limb segments and the generation of an adequate muscular force to cope with the imminent collision with the ground. This study assesses how a hypogravitational environment affects the control of landing after a countermovement jump (CMJ). Eight participants performed submaximal CMJs on Earth (1-g condition) and in a weightlessness environment with simulated gravity conditions generated by a pull-down force (1-, 0.6-, 0.4-, and 0.2-g0 conditions). External forces applied to the body, movements of the lower limb segments, and muscular activity of six lower limb muscles were recorded. 1) All subjects were able to jump and stabilize their landing in all experimental conditions, except one subject in 0.2-g0 condition. 2) The mechanical behavior of lower limb muscles switches during landing from a stiff spring to a compliant spring associated with a damper. This is true whatever the environment, on Earth as well as in environments where sensory inputs are altered. 3) The motor control of landing in simulated 1 g0 reveals an increased "safety margin" strategy, illustrated by increased stiffness and damping coefficient compared with landing on Earth. 4) The motor command is adjusted to the task constraints: muscular activity of lower limb extensors and flexors, stiffness and damping coefficient decrease according to the decreased gravity level. Our results show that even if in daily living gravity can be perceived as a constant factor, subjects can cope with altered sensory signals, taking advantage of the remaining information (visual and/or decreased proprioceptive inputs). PMID:26846555

  10. Vortex jump behavior in coupled nanomagnetic heterostructures

    SciTech Connect

    Zhang, S.; Phatak, C.; Petford-Long, A. K.; Heinonen, O.

    2014-11-24

    The spin configuration and magnetic behavior in patterned nanostructures can be controlled by manipulating the interplay between the competing energy terms. This in turn requires fundamental knowledge of the magnetic interactions at the local nanometer scale. Here, we report on the spin structure and magnetization behavior of patterned discs containing exchange coupled ferromagnetic layers with additional exchange bias to an antiferromagnetic layer. The magnetization reversal was explored by direct local visualization of the domain behavior using in-situ Lorentz transmission electron microscopy, from which quantitative magnetic induction maps were reconstructed. The roles of the main competing energy terms were elucidated and the reversal mechanism was identified as a coupled phenomenon of incoherent rotation in the exchange-biased layer and localized vortex nucleation and discontinuous propagation in the free layer, including an anomalous jump in the trajectory. The observations were supported by micromagnetic simulations and modeled phase shift simulations. The work presented here provides fundamental insights into opportunities for macroscopic control of the energy landscape of magnetic heterostructures for functional applications.

  11. A jumping shape memory alloy under heat.

    PubMed

    Yang, Shuiyuan; Omori, Toshihiro; Wang, Cuiping; Liu, Yong; Nagasako, Makoto; Ruan, Jingjing; Kainuma, Ryosuke; Ishida, Kiyohito; Liu, Xingjun

    2016-01-01

    Shape memory alloys are typical temperature-sensitive metallic functional materials due to superelasticity and shape recovery characteristics. The conventional shape memory effect involves the formation and deformation of thermally induced martensite and its reverse transformation. The shape recovery process usually takes place over a temperature range, showing relatively low temperature-sensitivity. Here we report novel Cu-Al-Fe-Mn shape memory alloys. Their stress-strain and shape recovery behaviors are clearly different from the conventional shape memory alloys. In this study, although the Cu-12.2Al-4.3Fe-6.6Mn and Cu-12.9Al-3.8Fe-5.6Mn alloys possess predominantly L21 parent before deformation, the 2H martensite stress-induced from L21 parent could be retained after unloading. Furthermore, their shape recovery response is extremely temperature-sensitive, in which a giant residual strain of about 9% recovers instantly and completely during heating. At the same time, the phenomenon of the jumping of the sample occurs. It is originated from the instantaneous completion of the reverse transformation of the stabilized 2H martensite. This novel Cu-Al-Fe-Mn shape memory alloys have great potentials as new temperature-sensitive functional materials. PMID:26880700

  12. A jumping shape memory alloy under heat

    NASA Astrophysics Data System (ADS)

    Yang, Shuiyuan; Omori, Toshihiro; Wang, Cuiping; Liu, Yong; Nagasako, Makoto; Ruan, Jingjing; Kainuma, Ryosuke; Ishida, Kiyohito; Liu, Xingjun

    2016-02-01

    Shape memory alloys are typical temperature-sensitive metallic functional materials due to superelasticity and shape recovery characteristics. The conventional shape memory effect involves the formation and deformation of thermally induced martensite and its reverse transformation. The shape recovery process usually takes place over a temperature range, showing relatively low temperature-sensitivity. Here we report novel Cu-Al-Fe-Mn shape memory alloys. Their stress-strain and shape recovery behaviors are clearly different from the conventional shape memory alloys. In this study, although the Cu-12.2Al-4.3Fe-6.6Mn and Cu-12.9Al-3.8Fe-5.6Mn alloys possess predominantly L21 parent before deformation, the 2H martensite stress-induced from L21 parent could be retained after unloading. Furthermore, their shape recovery response is extremely temperature-sensitive, in which a giant residual strain of about 9% recovers instantly and completely during heating. At the same time, the phenomenon of the jumping of the sample occurs. It is originated from the instantaneous completion of the reverse transformation of the stabilized 2H martensite. This novel Cu-Al-Fe-Mn shape memory alloys have great potentials as new temperature-sensitive functional materials.

  13. A jumping shape memory alloy under heat

    PubMed Central

    Yang, Shuiyuan; Omori, Toshihiro; Wang, Cuiping; Liu, Yong; Nagasako, Makoto; Ruan, Jingjing; Kainuma, Ryosuke; Ishida, Kiyohito; Liu, Xingjun

    2016-01-01

    Shape memory alloys are typical temperature-sensitive metallic functional materials due to superelasticity and shape recovery characteristics. The conventional shape memory effect involves the formation and deformation of thermally induced martensite and its reverse transformation. The shape recovery process usually takes place over a temperature range, showing relatively low temperature-sensitivity. Here we report novel Cu-Al-Fe-Mn shape memory alloys. Their stress-strain and shape recovery behaviors are clearly different from the conventional shape memory alloys. In this study, although the Cu-12.2Al-4.3Fe-6.6Mn and Cu-12.9Al-3.8Fe-5.6Mn alloys possess predominantly L21 parent before deformation, the 2H martensite stress-induced from L21 parent could be retained after unloading. Furthermore, their shape recovery response is extremely temperature-sensitive, in which a giant residual strain of about 9% recovers instantly and completely during heating. At the same time, the phenomenon of the jumping of the sample occurs. It is originated from the instantaneous completion of the reverse transformation of the stabilized 2H martensite. This novel Cu-Al-Fe-Mn shape memory alloys have great potentials as new temperature-sensitive functional materials. PMID:26880700

  14. How Can We Tell if Frogs Jump Further?

    ERIC Educational Resources Information Center

    Drummond, Gordon B.; Tom, Brian D. M.

    2011-01-01

    How effective is training frogs to jump? This is perhaps the most frequent question in biology that is subjected to statistical analysis: does a treatment make a difference? One can examine whether there is indeed a training effect, by first assuming the opposite. That is, the authors assume that training has no effect on the mean distance jumped.…

  15. Lift-off dynamics in a simple jumping robot

    NASA Astrophysics Data System (ADS)

    Aguilar, Jeffrey; Lesov, Alex; Wiesenfeld, Kurt; Goldman, Daniel I.

    2013-03-01

    Jumping is an important behavior utilized by animals to escape predation, hunt, reach higher ground, and as a primary mode of locomotion. Many mathematical and physical robot models use numerous parameters and multi-link legs to accurately model jumping dynamics. However, a simple robot model can reveal important principles of high performance jumping. We study vertical jumping in a simple robot comprising an actuated mass-spring arrangement. The actuator frequency and phase are systematically varied to find optimal performance. Optimal jumps occur above and below (but not at) the robot's resonant frequency f0. Two distinct jumping modes emerge: a simple jump which is optimal above f0 is achievable with a squat maneuver, and a peculiar stutter jump which is optimal below f0 is generated with a counter-movement. A simple dynamical model reveals how optimal lift-off results from non-resonant transient dynamics. An expanded explanation of this work is provided at http://crablab.gatech.edu/pages/jumpingrobot/index.html This work was supported by the GEM Consortium, Burroughs Wellcome Fund, ARL MAST CTA, and NSF PoLS.

  16. A unified model for the long and high jump

    NASA Astrophysics Data System (ADS)

    Helene, O.; Yamashita, M. T.

    2005-10-01

    A simple model based on the maximum energy that an athlete can produce in a small time interval is used to describe the high and long jump. Conservation of angular momentum is used to explain why an athlete should run horizontally to perform a vertical jump. Our results agree with world records.

  17. A Safe and Effective Modification of Thomson's Jumping Ring Experiment

    ERIC Educational Resources Information Center

    Waschke, Felix; Strunz, Andreas; Meyn, Jan-Peter

    2012-01-01

    The electrical circuit of the jumping ring experiment based on discharging a capacitor is optimized. The setup is scoop proof at 46 V and yet the ring jumps more than 9 m high. The setup is suitable for both lectures and student laboratory work in higher education. (Contains 1 table, 8 figures and 3 footnotes.)

  18. Knee Muscular Control During Jump Landing in Multidirections

    PubMed Central

    Sinsurin, Komsak; Vachalathiti, Roongtiwa; Jalayondeja, Wattana; Limroongreungrat, Weerawat

    2016-01-01

    Background Jump landing is a complex movement in sports. While competing and practicing, athletes frequently perform multi-planar jump landing. Anticipatory muscle activity could influence the amount of knee flexion and prepare the knee for dynamic weight bearing such as landing tasks. Objectives The aim of the present study was to examine knee muscle function and knee flexion excursion as athletes naturally performed multi-direction jump landing. Materials and Methods Eighteen male athletes performed the jump-landing test in four directions: forward (0°), 30° diagonal, 60° diagonal, and lateral (90°). Muscles tested were vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF), semitendinosus (ST), and biceps femoris (BF). A ViconTM 612 workstation collected the kinematic data. An electromyography was synchronized with the ViconTM Motion system to quantify dynamic muscle function. Repeated measure ANOVA was used to analyze the data. Results Jump-landing direction significantly influenced (P < 0.05) muscle activities of VL, RF, and ST and knee flexion excursion. Jumpers landed with a trend of decreasing knee flexion excursion and ST muscle activity 100 ms before foot contact progressively from forward to lateral directions of jump landing. Conclusions A higher risk of knee injury might occur during lateral jump landing than forward and diagonal directions. Athletes should have more practice in jump landing in lateral direction to avoid injury. Landing technique with high knee flexion in multi-directions should be taught to jumpers for knee injury prevention. PMID:27625758

  19. Could the deep squat jump predict weightlifting performance?

    PubMed

    Vizcaya, Francisco J; Viana, Oscar; del Olmo, Miguel Fernandez; Acero, Rafael Martin

    2009-05-01

    This research was carried out with the aim of describing the deep squat jump (DSJ) and comparing it with the squat (SJ) and countermovement (CMJ) jumps, to introduce it as a strength testing tool in the monitoring and control of training in strength and power sports. Forty-eight male subjects (21 weightlifters, 12 triathletes, and 15 physical education students) performed 3 trials of DSJ, SJ, and CMJ with a 1-minute rest among them. For the weightlifters, snatch and clean and jerk results during the Spanish Championship 2004 and the 35th EU Championships 2007 were collected to study the relationship among vertical jumps and weightlifters' performance. A 1-way analysis of variance (ANOVA) showed significant differences between groups in the vertical jumps, with the highest jumps for the weightlifters and the lowest for the triathletes. An ANOVA for repeated measures (type of jump) showed better results for DSJ and CMJ than SJ in all groups. A linear regression analysis was performed to determine the association between weightlifting and vertical jump performances. Correlations among the weightlifting performance and the vertical jumps were also calculated and determined using Pearson r. Results have shown that both CMJ and DSJ are strongly correlated with weightlifting ability. Therefore, both measures can be useful for coaches as a strength testing tool in the monitoring and control of training in weightlifting. PMID:19387408

  20. Possible and Impossible Segments.

    ERIC Educational Resources Information Center

    Walker, Rachel; Pullum, Geoffrey K.

    1999-01-01

    Examines the relationship between phonetic possibility and phonological permissibility of segment types. Specific focus is on whether there are any phonetically impossible segments phonologically permissible, and whether there are any phonetically possible segments phonologically impermissable. Examines the case of nasality spreading in Sudanese…

  1. Velocity of DNA during translocation through a solid-state nanopore.

    PubMed

    Plesa, Calin; van Loo, Nick; Ketterer, Philip; Dietz, Hendrik; Dekker, Cees

    2015-01-14

    While understanding translocation of DNA through a solid-state nanopore is vital for exploiting its potential for sensing and sequencing at the single-molecule level, surprisingly little is known about the dynamics of the propagation of DNA through the nanopore. Here we use linear double-stranded DNA molecules, assembled by the DNA origami technique, with markers at known positions in order to determine for the first time the local velocity of different segments along the length of the molecule. We observe large intramolecular velocity fluctuations, likely related to changes in the drag force as the DNA blob unfolds. Furthermore, we observe an increase in the local translocation velocity toward the end of the translocation process, consistent with a speeding up due to unfolding of the last part of the DNA blob. We use the velocity profile to estimate the uncertainty in determining the position of a feature along the DNA given its temporal location and demonstrate the error introduced by assuming a constant translocation velocity. PMID:25496458

  2. FISH analysis with locus-specific probes in sperm from two translocation carrier men.

    PubMed

    Durak, B; Ozön, Y H; Ozdemir, M; Artan, S; Basaran, N; Basaran, S; Ozkinay, C

    1999-08-01

    Meiotic segregation of normal and derivative chromosomes was analysed in sperm samples from two balanced reciprocal translocation carrier men by use of dual-colour fluorescence in situ hybridisation (FISH) technique. The translocations were t(4;8)(p15;p12) and t(15;22)(q(23:q13.2), and the digoxigenin-labelled FISH probes were specific to either the translocated or centric segments of the chromosomes involved in the translocations. A total of 1000 spermatozoa for each probe were analysed and the modes of segregation were described on the basis of signals in each sperm cell. The mean frequency of alternate and/or adjacent-1 (adj-1) segregation types was 69.47%, whereas they were 30.51 and 78.70% for the adjacent-2 (adj-2) and alternate/adj-2 segregation types, respectively. This study illustrated that FISH is a valuable technique for analysing the meiotic segregation products of the heterozygotes in respect to aneuploidy risk. PMID:10517249

  3. Stochastic resonance during a polymer translocation process

    NASA Astrophysics Data System (ADS)

    Mondal, Debasish; Muthukumar, Murugappan

    We study the translocation of a flexible polymer in a confined geometry subjected to a time-periodic external drive to explore stochastic resonance. We describe the equilibrium translocation process in terms of a Fokker-Planck description and use a discrete two-state model to describe the effect of the external driving force on the translocation dynamics. We observe that no stochastic resonance is possible if the associated free-energy barrier is purely entropic in nature. The polymer chain experiences a stochastic resonance effect only in presence of an energy threshold in terms of polymer-pore interaction. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly.

  4. DNA nanopore translocation in glutamate solutions

    NASA Astrophysics Data System (ADS)

    Plesa, C.; van Loo, N.; Dekker, C.

    2015-08-01

    Nanopore experiments have traditionally been carried out with chloride-based solutions. Here we introduce silver/silver-glutamate-based electrochemistry as an alternative, and study the viscosity, conductivity, and nanopore translocation characteristics of potassium-, sodium-, and lithium-glutamate solutions. We show that it has a linear response at typical voltages and can be used to detect DNA translocations through a nanopore. The glutamate anion also acts as a redox-capable thickening agent, with high-viscosity solutions capable of slowing down the DNA translocation process by up to 11 times, with a corresponding 7 time reduction in signal. These results demonstrate that glutamate can replace chloride as the primary anion in nanopore resistive pulse sensing.

  5. Implementation of jump-diffusion algorithms for understanding FLIR scenes

    NASA Astrophysics Data System (ADS)

    Lanterman, Aaron D.; Miller, Michael I.; Snyder, Donald L.

    1995-07-01

    Our pattern theoretic approach to the automated understanding of forward-looking infrared (FLIR) images brings the traditionally separate endeavors of detection, tracking, and recognition together into a unified jump-diffusion process. New objects are detected and object types are recognized through discrete jump moves. Between jumps, the location and orientation of objects are estimated via continuous diffusions. An hypothesized scene, simulated from the emissive characteristics of the hypothesized scene elements, is compared with the collected data by a likelihood function based on sensor statistics. This likelihood is combined with a prior distribution defined over the set of possible scenes to form a posterior distribution. The jump-diffusion process empirically generates the posterior distribution. Both the diffusion and jump operations involve the simulation of a scene produced by a hypothesized configuration. Scene simulation is most effectively accomplished by pipelined rendering engines such as silicon graphics. We demonstrate the execution of our algorithm on a silicon graphics onyx/reality engine.

  6. Nonstandard jump functions for radially symmetric shock waves

    SciTech Connect

    Baty, Roy S.; Tucker, Don H.; Stanescu, Dan

    2008-10-01

    Nonstandard analysis is applied to derive generalized jump functions for radially symmetric, one-dimensional, magnetogasdynamic shock waves. It is assumed that the shock wave jumps occur on infinitesimal intervals, and the jump functions for the physical parameters occur smoothly across these intervals. Locally integrable predistributions of the Heaviside function are used to model the flow variables across a shock wave. The equations of motion expressed in nonconservative form are then applied to derive unambiguous relationships between the jump functions for the physical parameters for two families of self-similar flows. It is shown that the microstructures for these families of radially symmetric, magnetogasdynamic shock waves coincide in a nonstandard sense for a specified density jump function

  7. Nonstandard jump functions for radically symmetric shock waves

    SciTech Connect

    Baty, Roy S; Tucker, Don H; Stanescu, Dan

    2008-01-01

    Nonstandard analysis is applied to derive generalized jump functions for radially symmetric, one-dimensional, magnetogasdynamic shock waves. It is assumed that the shock wave jumps occur on infinitesimal intervals and the jump functions for the physical parameters occur smoothly across these intervals. Locally integrable predistributions of the Heaviside function are used to model the flow variables across a shock wave. The equations of motion expressed in nonconservative form are then applied to derive unambiguous relationships between the jump functions for the physical parameters for two families of self-similar flows. It is shown that the microstructures for these families of radially symmetric, magnetogasdynamic shock waves coincide in a nonstandard sense for a specified density jump function.

  8. Analyzing disease risks associated with translocations.

    PubMed

    Sainsbury, Anthony W; Vaughan-Higgins, Rebecca J

    2012-06-01

    Translocations of species are expected to be used increasingly to counter the undesirable effects of anthropogenic changes to ecosystems, including loss of species. Methods to assess the risk of disease associated with translocations have been compiled in a comprehensive manual of disease-risk analysis for movement of domestic animals. We used this manual to devise a qualitative method for assessing the probability of the occurrence of disease in wild animals associated with translocations. We adapted the method such that we considered a parasite (any agent of infectious or noninfectious disease) a hazard if it or the host had crossed an ecological or geographical barrier and was novel to the host. We included in our analyses hazards present throughout the translocation pathway derived from the interactions between host immunity and the parasite, the effect of parasites on populations, the effect of noninfectious disease agents, and the effect of stressors on host-parasite interactions. We used the reintroduction of Eurasian Cranes (Grus grus) to England to demonstrate our method. Of the 24 hazards identified, 1 was classified as high risk (coccidia) and 5 were medium risk (highly pathogenic avian influenza virus, Mycobacterium avium, Aspergillus fumigatus, tracheal worms [Syngamus sp. and Cyathostoma sp.], and Tetrameres spp.). Seventeen other hazards were considered low or very low risk. In the absence of better information on the number, identity, distribution, and pathogenicity of parasites of wild animals, there is uncertainty in the risk of disease to translocated animals and recipient populations. Surveys of parasites in source and destination populations and detailed health monitoring after release will improve the information available for future analyses of disease risk. We believe our method can be adapted to assess the risks of disease in other translocated populations. PMID:22533691

  9. Orientational Jumps in (Acetamide + Electrolyte) Deep Eutectics: Anion Dependence.

    PubMed

    Das, Suman; Biswas, Ranjit; Mukherjee, Biswaroop

    2015-08-27

    All-atom molecular dynamics simulations have been carried out to investigate orientation jumps of acetamide molecules in three different ionic deep eutectics made of acetamide (CH3CONH2) and lithium salts of bromide (Br(–)), nitrate (NO3(–)) and perchlorate (ClO4(–)) at approximately 80:20 mole ratio and 303 K. Orientational jumps have been dissected into acetamide–acetamide and acetamide–ion catagories. Simulated jump characteristics register a considerable dependence on the anion identity. For example, large angle jumps are relatively less frequent in the presence of NO3(–) than in the presence of the other two anions. Distribution of jump angles for rotation of acetamide molecules hydrogen bonded (H-bonded) to anions has been found to be bimodal in the presence of Br(–) and is qualitatively different from the other two cases. Estimated energy barrier for orientation jumps of these acetamide molecules (H-bonded to anions) differ by a factor of ∼2 between NO3(–) and ClO4(–), the barrier height for the latter being lower and ∼0.5kBT. Relative radial and angular displacements during jumps describe the sequence ClO(4)– > NO3(–) > Br(–) and follow a reverse viscosity trend. Jump barrier for acetamide–acetamide pairs reflects weak dependence on anion identity and remains closer to the magnitude (∼0.7kBT) found for orientation jumps in molten acetamide. Jump time distributions exhibit a power law dependence of the type, P(tjump) ∝ A(tjump/τ)(−β), with both β and τ showing substantial anion dependence. The latter suggests the presence of dynamic heterogeneity in these systems and supports earlier conclusions from time-resolved fluorescence measurements. PMID:26131593

  10. Effects of Isometric Scaling on Vertical Jumping Performance

    PubMed Central

    Bobbert, Maarten F.

    2013-01-01

    Jump height, defined as vertical displacement in the airborne phase, depends on vertical takeoff velocity. For centuries, researchers have speculated on how jump height is affected by body size and many have adhered to what has come to be known as Borelli’s law, which states that jump height does not depend on body size per se. The underlying assumption is that the amount of work produced per kg body mass during the push-off is independent of size. However, if a big body is isometrically downscaled to a small body, the latter requires higher joint angular velocities to achieve a given takeoff velocity and work production will be more impaired by the force-velocity relationship of muscle. In the present study, the effects of pure isometric scaling on vertical jumping performance were investigated using a biologically realistic model of the human musculoskeletal system. The input of the model, muscle stimulation over time, was optimized using jump height as criterion. It was found that when the human model was miniaturized to the size of a mouse lemur, with a mass of about one-thousandth that of a human, jump height dropped from 40 cm to only 6 cm, mainly because of the force-velocity relationship. In reality, mouse lemurs achieve jump heights of about 33 cm. By implication, the unfavourable effects of the small body size of mouse lemurs on jumping performance must be counteracted by favourable effects of morphological and physiological adaptations. The same holds true for other small jumping animals. The simulations for the first time expose and explain the sheer magnitude of the isolated effects of isometric downscaling on jumping performance, to be counteracted by morphological and physiological adaptations. PMID:23936494

  11. Protein Translocation across the Rough Endoplasmic Reticulum

    PubMed Central

    Mandon, Elisabet C.; Trueman, Steven F.; Gilmore, Reid

    2013-01-01

    The rough endoplasmic reticulum is a major site of protein biosynthesis in all eukaryotic cells, serving as the entry point for the secretory pathway and as the initial integration site for the majority of cellular integral membrane proteins. The core components of the protein translocation machinery have been identified, and high-resolution structures of the targeting components and the transport channel have been obtained. Research in this area is now focused on obtaining a better understanding of the molecular mechanism of protein translocation and membrane protein integration. PMID:23251026

  12. What drives the translocation of proteins?

    PubMed Central

    Simon, S M; Peskin, C S; Oster, G F

    1992-01-01

    We propose that protein translocation across membranes is driven by biased random thermal motion. This "Brownian ratchet" mechanism depends on chemical asymmetries between the cis and trans sides of the membrane. Several mechanisms could contribute to rectifying the thermal motion of the protein, such as binding and dissociation of chaperonins to the translocating chain, chain coiling induced by pH and/or ionic gradients, glycosylation, and disulfide bond formation. This helps explain the robustness and promiscuity of these transport systems. Images PMID:1349170

  13. Multi-segment detector

    NASA Technical Reports Server (NTRS)

    George, Peter K. (Inventor)

    1978-01-01

    A plurality of stretcher detector segments are connected in series whereby detector signals generated when a bubble passes thereby are added together. Each of the stretcher detector segments is disposed an identical propagation distance away from passive replicators wherein bubbles are replicated from a propagation path and applied, simultaneously, to the stretcher detector segments. The stretcher detector segments are arranged to include both dummy and active portions thereof which are arranged to permit the geometry of both the dummy and active portions of the segment to be substantially matched.

  14. Detection of interchromosomal translocations within the Triticeae by RFLP analysis.

    PubMed

    King, I P; Purdie, K A; Liu, C J; Reader, S M; Pittaway, T S; Orford, S E; Miller, T E

    1994-10-01

    Twenty-three wheat/alien addition or substitution lines were screened using restriction fragment length polymorphisms for the presence or absence of 4/5 and 4/7 reciprocal translocations in the alien chromosomes. Such translocations have previously been identified in wheat and rye. Group 4 and group 5 Aegilops umbellulata, Triticum urartu, and Thinopyrum bessarabicum chromosomes were found to carry 4/5 translocations. Evidence for a 4/7 translocation was also found in Secale montanum. The presence of the 4/5 translocations in T. urartu indicates that the translocation predates the polyploidization of wheat. The implications of these results are discussed. PMID:18470131

  15. Annealed Importance Sampling Reversible Jump MCMC algorithms

    SciTech Connect

    Karagiannis, Georgios; Andrieu, Christophe

    2013-03-20

    It will soon be 20 years since reversible jump Markov chain Monte Carlo (RJ-MCMC) algorithms have been proposed. They have significantly extended the scope of Markov chain Monte Carlo simulation methods, offering the promise to be able to routinely tackle transdimensional sampling problems, as encountered in Bayesian model selection problems for example, in a principled and flexible fashion. Their practical efficient implementation, however, still remains a challenge. A particular difficulty encountered in practice is in the choice of the dimension matching variables (both their nature and their distribution) and the reversible transformations which allow one to define the one-to-one mappings underpinning the design of these algorithms. Indeed, even seemingly sensible choices can lead to algorithms with very poor performance. The focus of this paper is the development and performance evaluation of a method, annealed importance sampling RJ-MCMC (aisRJ), which addresses this problem by mitigating the sensitivity of RJ-MCMC algorithms to the aforementioned poor design. As we shall see the algorithm can be understood as being an “exact approximation” of an idealized MCMC algorithm that would sample from the model probabilities directly in a model selection set-up. Such an idealized algorithm may have good theoretical convergence properties, but typically cannot be implemented, and our algorithms can approximate the performance of such idealized algorithms to an arbitrary degree while not introducing any bias for any degree of approximation. Our approach combines the dimension matching ideas of RJ-MCMC with annealed importance sampling and its Markov chain Monte Carlo implementation. We illustrate the performance of the algorithm with numerical simulations which indicate that, although the approach may at first appear computationally involved, it is in fact competitive.

  16. The Circular Hydraulic Jump in Microgravity

    NASA Technical Reports Server (NTRS)

    Avedisian, C. Thomas

    1996-01-01

    This report summarizes the key experimental results and observations that were obtained under NASA grant NAG 3-1627 from the Fluid Physics Program. The Principle Investigator was Thomas Avedisian. In addition a half-time post-doctoral associate, Ziqun Zhao, was funded for half year. The project monitor was David Chao of the NASA-Lewis Research Center in Cleveland, Ohio. The grant period was originally for one year at $34K and a no-cost extension was applied for and granted for an additional year. The research consisted of an experimental study of the circular hydraulic jump (CHJ) in microgravity using water as the working fluid. The evolution of the CHJ radius was measured during a sudden transition from normal to microgravity in a drop tower. The downstream height of the CHJ was controlled by submerging the target plate in a tank filled with water to the desired depth, and the measurements are compared with an existing theory for the location of the CHJ. Results show that the CHJ diameter is larger in microgravity than normal gravity. The adjustment of the CHJ diameter to a sudden change in gravity occurs over a period of about 200ms for the conditions of the present study, and remains constant thereafter for most of the flow conditions examined. For flow conditions that a CHJ was not first established at normal gravity but which later appeared during the transition tb microgravity, the CHJ diameter was not constant during the period of microgravity but continually changed. Good agreement between measured and predicted CHJ radii is found for normal gravity CHJ radii, but comparatively poorer agreement is observed for the CHJ radii measurements in microgravity.

  17. Color image segmentation

    NASA Astrophysics Data System (ADS)

    McCrae, Kimberley A.; Ruck, Dennis W.; Rogers, Steven K.; Oxley, Mark E.

    1994-03-01

    The most difficult stage of automated target recognition is segmentation. Current segmentation problems include faces and tactical targets; previous efforts to segment these objects have used intensity and motion cues. This paper develops a color preprocessing scheme to be used with the other segmentation techniques. A neural network is trained to identify the color of a desired object, eliminating all but that color from the scene. Gabor correlations and 2D wavelet transformations will be performed on stationary images; and 3D wavelet transforms on multispectral data will incorporate color and motion detection into the machine visual system. The paper will demonstrate that color and motion cues can enhance a computer segmentation system. Results from segmenting faces both from the AFIT data base and from video taped television are presented; results from tactical targets such as tanks and airplanes are also given. Color preprocessing is shown to greatly improve the segmentation in most cases.

  18. Estimation of Joint Forces and Moments for the In-Run and Take-Off in Ski Jumping Based on Measurements with Wearable Inertial Sensors

    PubMed Central

    Logar, Grega; Munih, Marko

    2015-01-01

    This study uses inertial sensors to measure ski jumper kinematics and joint dynamics, which was until now only a part of simulation studies. For subsequent calculation of dynamics in the joints, a link-segment model was developed. The model relies on the recursive Newton–Euler inverse dynamics. This approach allowed the calculation of the ground reaction force at take-off. For the model validation, four ski jumpers from the National Nordic center performed a simulated jump in a laboratory environment on a force platform; in total, 20 jumps were recorded. The results fit well to the reference system, presenting small errors in the mean and standard deviation and small root-mean-square errors. The error is under 12% of the reference value. For field tests, six jumpers participated in the study; in total, 28 jumps were recorded. All of the measured forces and moments were within the range of prior simulated studies. The proposed system was able to indirectly provide the values of forces and moments in the joints of the ski-jumpers' body segments, as well as the ground reaction force during the in-run and take-off phases in comparison to the force platform installed on the table. Kinematics assessment and estimation of dynamics parameters can be applied to jumps from any ski jumping hill. PMID:25985167

  19. Estimation of joint forces and moments for the in-run and take-off in ski jumping based on measurements with wearable inertial sensors.

    PubMed

    Logar, Grega; Munih, Marko

    2015-01-01

    This study uses inertial sensors to measure ski jumper kinematics and joint dynamics, which was until now only a part of simulation studies. For subsequent calculation of dynamics in the joints, a link-segment model was developed. The model relies on the recursive Newton-Euler inverse dynamics. This approach allowed the calculation of the ground reaction force at take-off. For the model validation, four ski jumpers from the National Nordic center performed a simulated jump in a laboratory environment on a force platform; in total, 20 jumps were recorded. The results fit well to the reference system, presenting small errors in the mean and standard deviation and small root-mean-square errors. The error is under 12% of the reference value. For field tests, six jumpers participated in the study; in total, 28 jumps were recorded. All of the measured forces and moments were within the range of prior simulated studies. The proposed system was able to indirectly provide the values of forces and moments in the joints of the ski-jumpers' body segments, as well as the ground reaction force during the in-run and take-off phases in comparison to the force platform installed on the table. Kinematics assessment and estimation of dynamics parameters can be applied to jumps from any ski jumping hill. PMID:25985167

  20. DNA translocation through α-hemolysin nanopores with potential application to macromolecular data storage

    NASA Astrophysics Data System (ADS)

    Khulbe, Pramod K.; Mansuripur, Masud; Gruener, Raphael

    2005-05-01

    Digital information can be encoded in the building-block sequence of macromolecules, such as RNA and single-stranded DNA. Methods of "writing" and "reading" macromolecular strands are currently available, but they are slow and expensive. In an ideal molecular data storage system, routine operations such as write, read, erase, store, and transfer must be done reliably and at high speed within an integrated chip. As a first step toward demonstrating the feasibility of this concept, we report preliminary results of DNA readout experiments conducted in miniaturized chambers that are scalable to even smaller dimensions. We show that translocation of a single-stranded DNA molecule (consisting of 50 adenosine bases followed by 100 cytosine bases) through an ion channel yields a characteristic signal that is attributable to the two-segment structure of the molecule. We also examine the dependence of the translocation rate and speed on the adjustable parameters of the experiment.

  1. A Mortar Segment-to-Segment Frictional Contact Method for Large Deformations

    SciTech Connect

    Puso, M; Laursen, T

    2003-10-29

    Contact modeling is still one of the most difficult aspects of nonlinear implicit structural analysis. Most 3D contact algorithms employed today use node-on-segment approaches for contacting dissimilar meshes. Two pass node-on-segment contact approaches have the well known deficiency of locking due to over constraint. Furthermore, node-on-segment approaches suffer when individual nodes slide out of contact at contact surface boundaries or when contacting nodes slide from facet to facet. This causes jumps in the contact forces due to the discrete nature of the constraint enforcement and difficulties in convergence for implicit solution techniques. In a previous work, we developed a segment-to-segment contact approach based on the mortar method that was applicable to large deformation mechanics. The approach proved extremely robust since it eliminated the overconstraint which caused ''locking'' and provided smooth force variations in large sliding. Here, we extend this previous approach in to treat frictional contact problems. The proposed approach is then applied to several challenging frictional contact problems which demonstrate its effectiveness.

  2. Numerical simulations and modeling for stochastic biological systems with jumps

    NASA Astrophysics Data System (ADS)

    Zou, Xiaoling; Wang, Ke

    2014-05-01

    This paper gives a numerical method to simulate sample paths for stochastic differential equations (SDEs) driven by Poisson random measures. It provides us a new approach to simulate systems with jumps from a different angle. The driving Poisson random measures are assumed to be generated by stationary Poisson point processes instead of Lévy processes. Methods provided in this paper can be used to simulate SDEs with Lévy noise approximately. The simulation is divided into two parts: the part of jumping integration is based on definition without approximation while the continuous part is based on some classical approaches. Biological explanations for stochastic integrations with jumps are motivated by several numerical simulations. How to model biological systems with jumps is showed in this paper. Moreover, method of choosing integrands and stationary Poisson point processes in jumping integrations for biological models are obtained. In addition, results are illustrated through some examples and numerical simulations. For some examples, earthquake is chose as a jumping source which causes jumps on the size of biological population.

  3. Aerial jumping in the Trinidadian guppy (Poecilia reticulata).

    PubMed

    Soares, Daphne; Bierman, Hilary S

    2013-01-01

    Many fishes are able to jump out of the water and launch themselves into the air. Such behavior has been connected with prey capture, migration and predator avoidance. We found that jumping behavior of the guppy Poecilia reticulata is not associated with any of the above. The fish jump spontaneously, without being triggered by overt sensory cues, is not migratory and does not attempt to capture aerial food items. Here, we use high speed video imaging to analyze the kinematics of the jumping behavior P. reticulata. Fish jump from a still position by slowly backing up while using its pectoral fins, followed by strong body trusts which lead to launching into the air several body lengths. The liftoff phase of the jump is fast and fish will continue with whole body thrusts and tail beats, even when out of the water. This behavior occurs when fish are in a group or in isolation. Geography has had substantial effects on guppy evolution, with waterfalls reducing gene flow and constraining dispersal. We suggest that jumping has evolved in guppies as a behavioral phenotype for dispersal. PMID:23613883

  4. Experimental investigation on single person's jumping load model

    NASA Astrophysics Data System (ADS)

    Chen, Jun; Wang, Haoqi; Wang, Ling

    2015-12-01

    This paper presents a modified half-sine-squared load model of the jumping impulses for a single person. The model is based on a database of 22,921 experimentally measured single jumping load cycles from 100 test subjects. Threedimensional motion capture technology in conjunction with force plates was employed in the experiment to record jumping loads. The variation range and probability distribution of the controlling parameters for the load model such as the impact factor, jumping frequency and contact ratio, are discussed using the experimental data. Correlation relationships between the three parameters are investigated. The contact ratio and jumping frequency are identified as independent model parameters, and an empirical frequency-dependent function is derived for the impact factor. The feasibility of the proposed load model is established by comparing the simulated load curves with measured ones, and by comparing the acceleration responses of a single-degree-of-freedom system to the simulated and measured jumping loads. The results show that a realistic individual jumping load can be generated by the proposed method. This can then be used to assess the dynamic response of assembly structures.

  5. An LIII (2P3/2) subshell absorption jump ratio and jump factor for bismuth

    NASA Astrophysics Data System (ADS)

    Kaya, N.; Kobya, A. I.; Tıraşoğlu, E.; Apaydın, G.

    2008-11-01

    In this paper, we report on measurement of the first experimental LIII (2P3/2) subshell absorption jump ratio and jump factor value which were derived from new mass attenuation coefficients measured at the upper and lower energy branches of the LIII absorption edge using an energy dispersive x-ray fluorescence (EDXRF) spectrometer for bismuth. The measurements of mass attenuation coefficients, at 36 energies from 10.010 to 17.478 keV, were done in a transmission geometry utilizing the Ki (i = α, α1,2, β, β1,2) and Li (i = α, β, β1,2, γ, γ1, l) x-rays from different secondary source targets excited by the 59.543 keV γ-photons from an 241Am annular source and detected by an ultra-LEGe solid-state detector with a resolution of 0.15 keV at 5.9 keV. The results have been compared with theoretical values.

  6. Safety of probiotics: translocation and infection.

    PubMed

    Liong, Min-Tze

    2008-04-01

    The long history of safety has contributed to the acceptance of probiotics as a safe food adjunct. Consequently, many probiotic products and their applications have been granted GRAS (generally regarded as safe) status. However, this classification has been frequently generalized for all probiotic strains regardless of their application. Cases of probiotics from the genera Lactobacillus, Leuconostoc, Pediococcus, Enterococcus, and Bifidobacterium have been isolated from infection sites, leading to the postulation that these probiotics can translocate. Probiotic translocation is difficult to induce in healthy humans, and even if it does occur, detrimental effects are rare. Despite this, various reports have documented health-damaging effects of probiotic translocation in immunocompromised patients. Due to probiotics' high degree of safety and their morphological confusion with other pathogenic bacteria, they are often overlooked as contaminants and are least suspected as pathogens. However, the antibiotic resistance of some strains has increased the complexity of their eradication. Probiotic translocation and infection deserve further investigation and should become a facet of safety assessment so the negative effects of probiotics do not outweigh the benefits. PMID:18366533

  7. Familial cryptic translocation in Angelman syndrome

    SciTech Connect

    Weyerts, L.K.; Wiley, J.E.; Loud, K.M.

    1994-09-01

    The majority of patients with Angelman syndrome have been shown to have a cytogenetic or molecular deletion on the maternally derived chromosome 15. We report on a case of Angelman syndrome in which this deletion occurs as an unbalanced cryptic translocation involving chromosomes 14 and 15. The proband was diagnosed clinically as having Angelman syndrome. Multiple cytogenetic studies were done without detecting any deletion. When DNA probes (Oncor) specific for the Prader Willi/Angelman locus became available, the patient was restudied and found to be deleted for {open_quotes}region A{close_quotes} (D15S11) but not for {open_quotes}region B{close_quotes} (GABRB3). No other abnormality was detected. The proband`s mother was then studied. The chromosome 15 marker probe and D15S11 were detected on different chromosomes. Using alpha-satellite probes, a cryptic 14;15 translocation was uncovered. This balanced translocation was also found to be carried by the sister of the proband. This case, along with a case presented at the 1993 ASHG meeting, illustrates the need for using acrocentric probes when studying Angelman syndrome patients. The proband was studied using additional probes specific for this region and found to be deleted for SNRPN but not for D15S10. The breakpoint of the translocation in this patient delineates the smallest deletion of the Angelman syndrome region reported to date and therefore may represent the specific gene involved.

  8. Circular hydraulic jump on finite surfaces with capillary limit

    NASA Astrophysics Data System (ADS)

    Mohajer, Behzad; Li, Ri

    2015-11-01

    A round liquid jet impinging on a circular disc with free edge generates a thin liquid film in the center surrounded by a thick film. For low flow rates, the thick film is bounded by a stable rim around the disc edge and flows off only from one spot at the edge. The outer Froude number remains constant for varied flow rates and disc sizes but changes with the surface tension of the fluid. The jump radius increases linearly with the flow rate, and the linear slope varies with the surface tension. Due to the stable-rim edge condition, the constant outer Froude numbers observed in our study are different from the constant value reported by Duchesne et al. ["Constant Froude number in a circular hydraulic jump and its implication on the jump radius selection," Europhys. Lett. 107, 54002 (2014)]. Despite the constant outer Froude numbers being independent of the flow rate, the inner Froude number changes with the flow rate, which is due to the surface tension force at the jump location. Force analysis is conducted by taking into account the stable rim, and the derived equations provide the relationship of jump radius with the contact angle of the stable rim, disc size, and jet flow. The maximum outer Froude number and the minimum inner Froude number are theoretically analyzed. Depending on the pre-jump velocity profile and the surface tension force at the jump, the maximum outer Froude number could be larger than unity. The shape of free surface at the jump is analyzed to evaluate the theoretical assumption of steep jump.

  9. Jump-Down Performance Alterations after Space Flight

    NASA Technical Reports Server (NTRS)

    Reschke, M. F.; Kofman, I. S.; Cerisano, J. M.; Fisher, E. A.; Peters, B. T.; Miller, C. A.; Harm, D. L.; Bloomberg, J. J.

    2011-01-01

    INTRODUCTION: Successful jump performance requires functional coordination of visual, vestibular, and somatosensory systems, which are affected by prolonged exposure to microgravity. Astronauts returning from space flight exhibit impaired ability to coordinate effective landing strategies when jumping from a platform to the ground. This study compares jump strategies used by astronauts before and after flight, changes to those strategies within a test session, and recoveries in jump-down performance parameters across several postflight test sessions. These data were obtained as part of an ongoing interdisciplinary study (Functional Task Test, FTT) designed to evaluate both astronaut postflight functional performance and related physiological changes. METHODS: Seven astronauts from short-duration (Shuttle) and three from long-duration (International Space Station) flights performed 3 two-footed jumps from a platform 30 cm high onto a force plate that measured the ground reaction forces and center-of-pressure displacement from the landings. Neuromuscular activation data were collected from the medial gastrocnemius and anterior tibialis of both legs using surface electromyography electrodes. Two load cells in the platform measured the load exerted by each foot during the takeoff phase of the jump. Data were collected in 2 preflight sessions, on landing day (Shuttle only), and 1, 6, and 30 days after flight. RESULTS: Postural settling time was significantly increased on the first postflight test session and many of the astronauts tested were unable to maintain balance on their first jump landing but recovered by the third jump, showing a learning progression in which performance improvements could be attributed to adjustments in takeoff or landing strategy. Jump strategy changes were evident in reduced air time (time between takeoff and landing) and also in increased asymmetry in foot latencies on takeoff. CONCLUSIONS: The test results revealed significant decrements

  10. Detection of weak frequency jumps for GNSS onboard clocks.

    PubMed

    Huang, Xinming; Gong, Hang; Ou, Gang

    2014-05-01

    In this paper, a weak frequency jump detection method is developed for onboard clocks in global navigation satellite systems (GNSS). A Kalman filter is employed to facilitate the onboard real-time processing of atomic clock measurements, whose N-step prediction residuals are used to construct the weak frequency jump detector. Numerical simulations show that the method can successfully detect weak frequency jumps. The detection method proposed in this paper is helpful for autonomous integrity monitoring of GNSS satellite clocks, and can also be applied to other frequency anomalies with an appropriately modified detector. PMID:24802723

  11. Developing an Enhanced Lightning Jump Algorithm for Operational Use

    NASA Technical Reports Server (NTRS)

    Schultz, Christopher J.; Petersen, Walter A.; Carey, Lawrence D.

    2009-01-01

    Overall Goals: 1. Build on the lightning jump framework set through previous studies. 2. Understand what typically occurs in nonsevere convection with respect to increases in lightning. 3. Ultimately develop a lightning jump algorithm for use on the Geostationary Lightning Mapper (GLM). 4 Lightning jump algorithm configurations were developed (2(sigma), 3(sigma), Threshold 10 and Threshold 8). 5 algorithms were tested on a population of 47 nonsevere and 38 severe thunderstorms. Results indicate that the 2(sigma) algorithm performed best over the entire thunderstorm sample set with a POD of 87%, a far of 35%, a CSI of 59% and a HSS of 75%.

  12. Nonstandard Analysis and Jump Conditions for Converging Shock Waves

    NASA Technical Reports Server (NTRS)

    Baty, Roy S.; Farassat, Fereidoun; Tucker, Don H.

    2008-01-01

    Nonstandard analysis is an area of modern mathematics which studies abstract number systems containing both infinitesimal and infinite numbers. This article applies nonstandard analysis to derive jump conditions for one-dimensional, converging shock waves in a compressible, inviscid, perfect gas. It is assumed that the shock thickness occurs on an infinitesimal interval and the jump functions in the thermodynamic and fluid dynamic parameters occur smoothly across this interval. Predistributions of the Heaviside function and the Dirac delta measure are introduced to model the flow parameters across a shock wave. The equations of motion expressed in nonconservative form are then applied to derive unambiguous relationships between the jump functions for the flow parameters.

  13. Genetic counselling in carriers of reciprocal chromosomal translocations involving short arm of chromosome X.

    PubMed

    Panasiuk, Barbara; Usinskiené, Ruta; Kostyk, Ewa; Rybałko, Alicja; Stasiewicz-Jarocka, Beata; Krzykwa, Bogustawa; Pieńkowska-Grela, Barbara; Kucinskas, Vaidutis; Michalova, Kyra; Midro, Alina T

    2004-01-01

    A central concept in genetic counselling is the estimation of the probability of occurrence of unbalanced progeny at birth and other unfavourable outcomes of pregnancy (miscarriages, stillbirths and early death). The estimation of the occurrence probability for individual carriers of four different X-autosome translocations with breakpoints at Xp, namely t(X;5)(p22.2;q32), t(X;6)(p11.2;q21), t(X;7)(p22.2;p11.1), and t(X;22)(p22.1;p11.1), is presented. The breakpoint positions of chromosomal translocations were interpreted using GTG, RBG and FISH-wcp. Most of these translocations were detected in women with normal phenotype, karyotyped because of repeated miscarriages and/or malformed progeny. A girl with very rare pure trisomy Xp22.1-->pter and a functional Xp disomy was ascertained in one family and her clinical picture has been described in details. It has been suggested that not fully skewed X chromosome inactivation of X-autosome translocation with breakpoint positions at Xp22 (critical segment) could influence the phenotype and risk value. Therefore, the X inactivation status was additionally evaluated by analysis of replication banding patterns using RBG technique after incorporation of BrdU. In two carriers of translocations: t(X;5)(p22.2;q32) and t(X;7)(p22.2;p11.1), late replication state of der(X) was observed in 5/100 and 10/180 analysed cells, respectively. In these both cases the breakpoint positions were clustered at the critical segment Xp22.2. In two other cases, one with the breakpoint position within [t(X;22)(p22.1;p11.1)] and one outside the critical region [t(X;6)(p11.2;q21)], fully skewed inactivation was seen. Therefore, we suggest that neither the distribution of the breakpoint positions nor fully skewed inactivation influenced the phenotype of observed t(X;A) carriers. The occurrence probabilities of the unbalanced progeny were calculated according to Stene and Stengel-Rutkowski along with application of updated available empirical data. In

  14. Identification of an Essential Region for Translocation of Clostridium difficile Toxin B.

    PubMed

    Chen, Shuyi; Wang, Haiying; Gu, Huawei; Sun, Chunli; Li, Shan; Feng, Hanping; Wang, Jufang

    2016-01-01

    Clostridium difficile toxin A (TcdA) and toxin B (TcdB) are the major virulence factors involved in C. difficile-associated diarrhea and pseudomembranous colitis. TcdA and TcdB both contain at least four distinct domains: the glucosyltransferase domain, cysteine protease domain, receptor binding domain, and translocation domain. Few studies have investigated the translocation domain and its mechanism of action. Recently, it was demonstrated that a segment of 97 amino acids (AA 1756-1852, designated D97) within the translocation domain of TcdB is essential for the in vitro and in vivo toxicity of TcdB. However, the mechanism by which D97 regulates the action of TcdB in host cells and the important amino acids within this region are unknown. In this study, we discovered that a smaller fragment, amino acids 1756-1780, located in the N-terminus of the D97 fragment, is essential for translocation of the effector glucosyltransferase domain into the host cytosol. A sequence of 25AA within D97 is predicted to form an alpha helical structure and is the critical part of D97. The deletion mutant TcdB∆1756-1780 showed similar glucosyltransferase and cysteine protease activity, cellular binding, and pore formation to wild type TcdB, but it failed to induce the glucosylation of Rho GTPase Rac1 of host cells. Moreover, we found that TcdB∆1756-1780 was rapidly degraded in the endosome of target cells, and therefore its intact glucosyltransferase domain was unable to translocate efficiently into host cytosol. Our finding provides an insight into the molecular mechanisms of action of TcdB in the intoxication of host cells. PMID:27537911

  15. Identification of an Essential Region for Translocation of Clostridium difficile Toxin B

    PubMed Central

    Chen, Shuyi; Wang, Haiying; Gu, Huawei; Sun, Chunli; Li, Shan; Feng, Hanping; Wang, Jufang

    2016-01-01

    Clostridium difficile toxin A (TcdA) and toxin B (TcdB) are the major virulence factors involved in C. difficile-associated diarrhea and pseudomembranous colitis. TcdA and TcdB both contain at least four distinct domains: the glucosyltransferase domain, cysteine protease domain, receptor binding domain, and translocation domain. Few studies have investigated the translocation domain and its mechanism of action. Recently, it was demonstrated that a segment of 97 amino acids (AA 1756–1852, designated D97) within the translocation domain of TcdB is essential for the in vitro and in vivo toxicity of TcdB. However, the mechanism by which D97 regulates the action of TcdB in host cells and the important amino acids within this region are unknown. In this study, we discovered that a smaller fragment, amino acids 1756–1780, located in the N-terminus of the D97 fragment, is essential for translocation of the effector glucosyltransferase domain into the host cytosol. A sequence of 25AA within D97 is predicted to form an alpha helical structure and is the critical part of D97. The deletion mutant TcdB∆1756–1780 showed similar glucosyltransferase and cysteine protease activity, cellular binding, and pore formation to wild type TcdB, but it failed to induce the glucosylation of Rho GTPase Rac1 of host cells. Moreover, we found that TcdB∆1756–1780 was rapidly degraded in the endosome of target cells, and therefore its intact glucosyltransferase domain was unable to translocate efficiently into host cytosol. Our finding provides an insight into the molecular mechanisms of action of TcdB in the intoxication of host cells. PMID:27537911

  16. Aeromechanics of the Spider Cricket Jump: How to Jump 60+ Times Your Body Length and Still Land on Your Feet

    NASA Astrophysics Data System (ADS)

    Palmer, Emily; Deshler, Nicolas; Gorman, David; Neves, Catarina; Mittal, Rajat

    2015-11-01

    Flapping, gliding, running, crawling and swimming have all been studied extensively in the past and have served as a source of inspiration for engineering designs. In the current project, we explore a mode of locomotion that straddles ground and air: jumping. The subject of our study is among the most proficient of long-jumpers in Nature: the spider cricket of the family Rhaphidophoridae, which can jump more than 60 times its body length. Despite jumping this immense distance, these crickets usually land on their feet, indicating an ability to control their posture during ``flight.'' We employ high-speed videogrammetry, to examine the jumps and to track the crickets' posture and appendage orientation throughout their jumps. Simple aerodynamic models are developed to predict the aerodynamic forces and moment on the crickets during `flight`. The analysis shows that these wingless insects employ carefully controlled and coordinated positioning of the limbs during flight so as to increase jump distance and to stabilize body posture during flight. The principles distilled from this study could serve as an inspiration for small jumping robots that can traverse complex terrains.

  17. Time-Resolved Charge Translocation by Sarcoplasmic Reticulum Ca-ATPase Measured on a Solid Supported Membrane

    PubMed Central

    Buoninsegni, Francesco Tadini; Bartolommei, Gianluca; Moncelli, Maria Rosa; Inesi, Giuseppe; Guidelli, Rolando

    2004-01-01

    Sarcoplasmic reticulum vesicles were adsorbed on an octadecanethiol/phosphatidylcholine mixed bilayer anchored to a gold electrode, and the Ca-ATPase contained in the vesicles was activated by ATP concentration jumps both in the absence and in the presence of K+ ions and at different pH values. Ca2+ concentration jumps in the absence of ATP were also carried out. The resulting capacitive current transients were analyzed together with the charge under the transients. The relaxation time constants of the current transients were interpreted on the basis of an equivalent circuit. The current transient after ATP concentration jumps and the charge after Ca2+ concentration jumps in the absence of ATP exhibit almost the same dependence upon the Ca2+ concentration, with a half-saturating value of ∼1.5 μM. The pH dependence of the charge after Ca2+ translocation demonstrates the occurrence of one H+ per one Ca2+ countertransport at pH 7 by direct charge-transfer measurements. The presence of K+ decreases the magnitude of the current transients without altering their shape; this decrease is explained by K+ binding to the cytoplasmic side of the pump in the E1 conformation and being released to the same side during the E1–E2 transition. PMID:15189864

  18. USEFULNESS AND METABOLIC IMPLICATIONS OF A 60-SECOND REPEATED JUMPS TEST AS A PREDICTOR OF ACROBATIC JUMPING PERFORMANCE IN GYMNASTS

    PubMed Central

    Rodríguez, F.A.

    2013-01-01

    Gymnastics floor exercises are composed of a set of four to five successive acrobatic jumps usually called a “series”. The aims of the study were: 1) to relate the acrobatic gymnastics performance of these series with a repeated jumps test of similar duration (R60), 2) to study the relation between R60 and physiological parameters (heart rate and blood lactate), and the performance obtained in different kinds of jumps, 3) to confirm whether R60, executed without a damped jumping technique, can be considered an anaerobic lactic power test. Twenty male and twenty-four female gymnasts performed three repeated jumps tests for 5 s (R5), 10 s (R10) and 60 s (R60) and vertical jumps, such as drop jumps (DJ), squat jumps (SJ) and countermovement jumps (CMJ). We assessed heart rate (HR) and blood lactate during R10 and R60. The average values of the maximal blood lactate concentration (Lmax) after R10 (males = 2.5±0.6 mmol · l−1; females = 2.1±0.8 mmol · l−1) confirm that anaerobic glycolysis is not activated to a high level. In R60, the Lmax (males = 7.5±1.7 mmol · l−1 females = 5.9±2.1 mmol · l−1) that was recorded does not validate R60 as an anaerobic lactic power test. We confirmed the relation between the average power obtained in R60 (R60Wm) and the acrobatic performance on the floor. The inclusion in the multiple regression equation of the best power in DJ and the best flight-contact ratio (FC) in R5 confirms the influence of other non-metabolic components on the variability in R60 performance, at least in gymnasts. PMID:24744459

  19. Investigating binding particles distribution effects on polymer translocation through nanopore

    NASA Astrophysics Data System (ADS)

    Haji Abdolvahab, Rouhollah

    2016-03-01

    Chaperone driven polymer translocation is an important model for biopolymer's translocation in vivo. Binding proteins spatial distribution is a significant factor in calculating the translocation time of the polymer in this type of translocation. Here using a dynamical Monte Carlo simulation we compare the results of the usual uniform distribution with the exponential distribution of different rates for a stiff polymer. Our simulation results show that just by changing the chaperones spatial distribution the translocation time of the biopolymer will change by as large as an order. It can change the translocation regime of the polymer completely from a diffusive to a ballistic one. Although generally increasing the exponential rate and the background concentration will increase the translocation velocity, it is not always true and one should consider both the sequence and the background concentration. We show that the results depend on the sequence and changing the distribution rates for increasing the translocation velocity will change the whole Probability Density Function (PDF) of the polymer translocation time accordance to its sequence. The translocation time sequence dependency will change in the extreme cases e.g. in the high exponential rate. Investigating the binding protein size, λ, also shows the importance of the so called parking lot effect in distribution dependency of the translocation velocity. Although there is not any important dependency for λ = 1, translocation time depends clearly on the chaperone spatial distribution for the case of λ ≥ 2.

  20. Impact assisted segmented cutterhead

    DOEpatents

    Morrell, Roger J.; Larson, David A.; Ruzzi, Peter L.

    1992-01-01

    An impact assisted segmented cutterhead device is provided for cutting various surfaces from coal to granite. The device comprises a plurality of cutting bit segments deployed in side by side relationship to form a continuous cutting face and a plurality of impactors individually associated with respective cutting bit segments. An impactor rod of each impactor connects that impactor to the corresponding cutting bit segment. A plurality of shock mounts dampening the vibration from the associated impactor. Mounting brackets are used in mounting the cutterhead to a base machine.

  1. Chasing maximal performance: a cautionary tale from the celebrated jumping frogs of Calaveras County.

    PubMed

    Astley, H C; Abbott, E M; Azizi, E; Marsh, R L; Roberts, T J

    2013-11-01

    Maximal performance is an essential metric for understanding many aspects of an organism's biology, but it can be difficult to determine because a measured maximum may reflect only a peak level of effort, not a physiological limit. We used a unique opportunity provided by a frog jumping contest to evaluate the validity of existing laboratory estimates of maximum jumping performance in bullfrogs (Rana catesbeiana). We recorded video of 3124 bullfrog jumps over the course of the 4-day contest at the Calaveras County Jumping Frog Jubilee, and determined jump distance from these images and a calibration of the jump arena. Frogs were divided into two groups: 'rental' frogs collected by fair organizers and jumped by the general public, and frogs collected and jumped by experienced, 'professional' teams. A total of 58% of recorded jumps surpassed the maximum jump distance in the literature (1.295 m), and the longest jump was 2.2 m. Compared with rental frogs, professionally jumped frogs jumped farther, and the distribution of jump distances for this group was skewed towards long jumps. Calculated muscular work, historical records and the skewed distribution of jump distances all suggest that the longest jumps represent the true performance limit for this species. Using resampling, we estimated the probability of observing a given jump distance for various sample sizes, showing that large sample sizes are required to detect rare maximal jumps. These results show the importance of sample size, animal motivation and physiological conditions for accurate maximal performance estimates. PMID:24133149

  2. Can jumping capacity of adult show jumping horses be predicted on the basis of submaximal free jumps at foal age? A longitudinal study.

    PubMed

    Bobbert, Maarten F; Santamaría, Susana; van Weeren, P René; Back, Wim; Barneveld, Albert

    2005-09-01

    The purpose of this study was to quantify performance characteristics of good jumping horses, and to determine whether these were already detectable at foal age. Kinematic data were collected of horses performing free jumps over a 0.60 m high fence at six months of age and of these same horses jumping with a rider over a 1.15 m high fence at five years of age. At five years of age the horses were divided into three groups on the basis of a puissance competition: a group of seven best jumpers that made no errors and in the end cleared a 1.50 m high fence, a group of nine worst jumpers that were unable to clear a 1.40 m high fence, and an intermediate group of 13 horses. Longitudinal kinematic data was available for all seven best jumpers and for six of the nine worst jumpers. Average values of variables for the best jumpers were compared with those of the worst jumpers for the jumps over 1.15 m. In the group of best jumpers, the forelimbs were shorter at forelimb clearance due to increased elbow flexion, and the hind limbs were further retroflexed at hind limb clearance. The same superior technique in clearing fences with the limbs was also found in this group at six months of age. Nevertheless, for individual horses it turned out to be too far-fetched to predict adult jumping capacity on the basis of kinematic variables collected during submaximal jumps at foal age. PMID:16129341

  3. Circular Hydraulic Jumps Triggered by Boundary Layer Separation.

    PubMed

    Chang; Demekhin; Takhistov

    2001-01-15

    When a high-flow-rate circular jet impinges vertically on a horizontal plane, it flows out radially and then undergoes a distinctive hydraulic jump on the plane because of boundary layer separation induced by hydrostatic back pressure. The jump radius is shown to be 0.37 a Re(1/3) Lambda(-1/8), where Lambda=(ga(3)/nu(2)) Re(-7/3) is a modified Froude number, Re=(Q/anu) is the jet Reynolds number, a is the jet radius, and Q the liquid flow rate, which is favorably compared to experimental data in the limit of small Lambda. When Lambda exceeds 3.0x10(-4) at low flow rates, the jump radius decreases below a minimum in the film depth and our experiments detect a different jump mechanism that may be triggered by capillary pressure rather than hydrostatic pressure. Copyright 2001 Academic Press. PMID:11121283

  4. Analysis and Model Tests of Autogiro Jump Take-off

    NASA Technical Reports Server (NTRS)

    Wheatley, John B; Bioletti, Carlton

    1936-01-01

    An analysis is made of the autogiro jump take-off, in which the kinetic energy of the rotor turning at excess speed is used to effect a vertical take-off. By the use of suitable approximations, the differential equation of motion of the rotor during this maneuver is reduced to a form that can be solved. Only the vertical jump was studied; the effect of a forward motion during the jump is discussed briefly. The results of model tests of the jump take-off have been incorporated in the paper and used to establish the relative accuracy of the results predicted from the analysis. Good agreement between calculation and experiment was obtained by making justifiable allowances.

  5. The exit-time problem for a Markov jump process

    SciTech Connect

    Burch, N.; D'Elia, Marta; Lehoucq, Richard B.

    2014-12-15

    The purpose of our paper is to consider the exit-time problem for a finite-range Markov jump process, i.e, the distance the particle can jump is bounded independent of its location. Such jump diffusions are expedient models for anomalous transport exhibiting super-diffusion or nonstandard normal diffusion. We refer to the associated deterministic equation as a volume-constrained nonlocal diffusion equation. The volume constraint is the nonlocal analogue of a boundary condition necessary to demonstrate that the nonlocal diffusion equation is well-posed and is consistent with the jump process. A critical aspect of the analysis is a variational formulation and a recently developed nonlocal vector calculus. Furthermore, this calculus allows us to pose nonlocal backward and forward Kolmogorov equations, the former equation granting the various moments of the exit-time distribution.

  6. The exit-time problem for a Markov jump process

    NASA Astrophysics Data System (ADS)

    Burch, N.; D'Elia, M.; Lehoucq, R. B.

    2014-12-01

    The purpose of this paper is to consider the exit-time problem for a finite-range Markov jump process, i.e, the distance the particle can jump is bounded independent of its location. Such jump diffusions are expedient models for anomalous transport exhibiting super-diffusion or nonstandard normal diffusion. We refer to the associated deterministic equation as a volume-constrained nonlocal diffusion equation. The volume constraint is the nonlocal analogue of a boundary condition necessary to demonstrate that the nonlocal diffusion equation is well-posed and is consistent with the jump process. A critical aspect of the analysis is a variational formulation and a recently developed nonlocal vector calculus. This calculus allows us to pose nonlocal backward and forward Kolmogorov equations, the former equation granting the various moments of the exit-time distribution.

  7. Single-Molecule FISH Reveals Non-selective Packaging of Rift Valley Fever Virus Genome Segments

    PubMed Central

    Wichgers Schreur, Paul J.; Kortekaas, Jeroen

    2016-01-01

    The bunyavirus genome comprises a small (S), medium (M), and large (L) RNA segment of negative polarity. Although genome segmentation confers evolutionary advantages by enabling genome reassortment events with related viruses, genome segmentation also complicates genome replication and packaging. Accumulating evidence suggests that genomes of viruses with eight or more genome segments are incorporated into virions by highly selective processes. Remarkably, little is known about the genome packaging process of the tri-segmented bunyaviruses. Here, we evaluated, by single-molecule RNA fluorescence in situ hybridization (FISH), the intracellular spatio-temporal distribution and replication kinetics of the Rift Valley fever virus (RVFV) genome and determined the segment composition of mature virions. The results reveal that the RVFV genome segments start to replicate near the site of infection before spreading and replicating throughout the cytoplasm followed by translocation to the virion assembly site at the Golgi network. Despite the average intracellular S, M and L genome segments approached a 1:1:1 ratio, major differences in genome segment ratios were observed among cells. We also observed a significant amount of cells lacking evidence of M-segment replication. Analysis of two-segmented replicons and four-segmented viruses subsequently confirmed the previous notion that Golgi recruitment is mediated by the Gn glycoprotein. The absence of colocalization of the different segments in the cytoplasm and the successful rescue of a tri-segmented variant with a codon shuffled M-segment suggested that inter-segment interactions are unlikely to drive the copackaging of the different segments into a single virion. The latter was confirmed by direct visualization of RNPs inside mature virions which showed that the majority of virions lack one or more genome segments. Altogether, this study suggests that RVFV genome packaging is a non-selective process. PMID:27548280

  8. Single-Molecule FISH Reveals Non-selective Packaging of Rift Valley Fever Virus Genome Segments.

    PubMed

    Wichgers Schreur, Paul J; Kortekaas, Jeroen

    2016-08-01

    The bunyavirus genome comprises a small (S), medium (M), and large (L) RNA segment of negative polarity. Although genome segmentation confers evolutionary advantages by enabling genome reassortment events with related viruses, genome segmentation also complicates genome replication and packaging. Accumulating evidence suggests that genomes of viruses with eight or more genome segments are incorporated into virions by highly selective processes. Remarkably, little is known about the genome packaging process of the tri-segmented bunyaviruses. Here, we evaluated, by single-molecule RNA fluorescence in situ hybridization (FISH), the intracellular spatio-temporal distribution and replication kinetics of the Rift Valley fever virus (RVFV) genome and determined the segment composition of mature virions. The results reveal that the RVFV genome segments start to replicate near the site of infection before spreading and replicating throughout the cytoplasm followed by translocation to the virion assembly site at the Golgi network. Despite the average intracellular S, M and L genome segments approached a 1:1:1 ratio, major differences in genome segment ratios were observed among cells. We also observed a significant amount of cells lacking evidence of M-segment replication. Analysis of two-segmented replicons and four-segmented viruses subsequently confirmed the previous notion that Golgi recruitment is mediated by the Gn glycoprotein. The absence of colocalization of the different segments in the cytoplasm and the successful rescue of a tri-segmented variant with a codon shuffled M-segment suggested that inter-segment interactions are unlikely to drive the copackaging of the different segments into a single virion. The latter was confirmed by direct visualization of RNPs inside mature virions which showed that the majority of virions lack one or more genome segments. Altogether, this study suggests that RVFV genome packaging is a non-selective process. PMID:27548280

  9. Acute leukemias of different lineages have similar MLL gene fusions encoding related chimeric proteins resulting from chromosomal translocation

    SciTech Connect

    Corral, J.; Forster, A.; Thompson, S.; Rabbitts, T.H. ); Lampert, F. ); Kaneko, Y. ); Slater, R.; Kroes, W.G. ); Van Der Schoot, C.E. ); Ludwig, W.D. ); Karpas, A. ); Pocock, C.; Cotter, F. )

    1993-09-15

    The MLL gene, on human chromosome 11q23, undergoes chromosomal translocation in acute leukemias, resulting in gene fusion with AF4 (chromosome 4) and ENL (chromosome 19). The authors report here translocation of MLL with nine different chromosomes and two paracentric chromosome 11 deletions in early B cell, B- or T-cell lineage, or nonlymphocytic acute leukemias. The mRNA translocation junction from 22t(4;11) patients, including six adult leukemias, and nine t(11;19) tumors reveals a remarkable conservation of breakpoints within MLL, AF4, or ENL genes, irrespective of tumor phenotype. Typically, the breakpoints are upstream of the zinc-finger region of MLL, and deletion of this region can accompany translocation, supporting the der(11) chromosome as the important component in leukemogenesis. Partial sequence of a fusion between MLL and the AFX1 gene from chromosome X shows the latter to be rich in Ser/Pro codons, like the ENL mRNA. These data suggest that the heterogeneous 11q23 abnormalities might cause attachment of Ser/Pro-rich segments to the NH[sub 2] terminus of MLL, lacking the zinc-finger region, and that translocation occurs in early hematopoietic cells, before commitment to distinct lineages. 36 refs., 2 figs.

  10. Jumping mechanisms and performance of snow fleas (Mecoptera, Boreidae).

    PubMed

    Burrows, Malcolm

    2011-07-15

    Flightless snow fleas (snow scorpion flies, Mecoptera, Boreidae) live as adults during northern hemisphere winters, often jumping and walking on the surface of snow. Their jumping mechanisms and performance were analysed with high speed imaging. Jumps were propelled by simultaneous movements of both the middle and hind pairs of legs, as judged by the 0.2 ms resolution afforded by image rates of 5000 frames s(-1). The middle legs of males represent 140% and the hindlegs 187% of the body length (3.4 mm), and the ratio of leg lengths is 1:1.3:1.7 (front:middle:hind). In preparation for a jump the middle legs and hindlegs were rotated forwards at their coxal joints with the fused mesothorax and metathorax. The first propulsive movement of a jump was the rotation of the trochantera about the coxae, powered by large depressor muscles within the thorax. The acceleration time was 6.6 ms. The fastest jump by a male had a take-off velocity of 1 m s(-1), which required 1.1 μJ of energy and a power output of 0.18 mW, and exerted a force about 16 times its body weight. Jump distances of about 100 mm were unaffected by temperature. This, and the power per mass of muscle requirement of 740 W kg(-1), suggests that a catapult mechanism is used. The elastic protein resilin was revealed in four pads at the articulation of the wing hinge with the dorsal head of the pleural ridge of each middle leg and hindleg. By contrast, fleas, which use just their hindlegs for jumping, have only two pads of resilin. This, therefore, provides a functional reference point for considerations about the phylogenetic relationships between snow fleas and true fleas. PMID:21697428

  11. Bifurcation and chaotic threshold of Duffing system with jump discontinuities

    NASA Astrophysics Data System (ADS)

    Tian, Ruilan; Zhou, Yufeng; Wang, Qiubao; Zhang, Lili

    2016-01-01

    Like for the smooth system, it is important to determine a criteria for bifurcation of the non-smooth system with jump discontinuities. Previously, the criteria have been constructed in some non-smooth systems with jump discontinuities which are the endpoints of interval. The research on bifurcation for non-smooth system with jump discontinuities, which are the interior points of interval, seems to be a new area. We construct the Duffing system with jump discontinuities in open interval. Bifurcation diagram of the unperturbed system is detected and Hamilton phase diagrams are simulated using Matlab. The jump discontinuities for the non-smooth Homoclinic orbit lead to a barrier for conventional nonlinear techniques to obtain the criteria for chaotic motion. Traditionally, these non-smooth factors were considered term by term. We will give a reasonable compromise based on all of characteristics of the non-smooth homoclinic orbits with the jump discontinuities. The extended Melnikov function is explicitly detected to judge the stable and unstable manifolds whether intersect transversally at any position of trajectory under the perturbation of damping and external forcing. It is worthwhile noting that the result reveals the effects of the non-smooth restoring force on the behaviors of nonlinear dynamical systems. The efficiency of the theoretical results is verified by the phase portraits, Poincaré surface of section, Largest Lyapnnov exponents diagram and bifurcation diagram.

  12. Bifilm Defect Formation in Hydraulic Jump of Liquid Aluminum

    NASA Astrophysics Data System (ADS)

    Hsu, Fu-Yuan

    2016-06-01

    In aluminum gravity casting, as liquid aluminum fell through a vertical sprue and impacted on the horizontal flat surface, a phenomenon known as hydraulic jump ( i.e., flow transition from super-critical to sub-critical flows) was observed. As the jump was transformed, a reverse eddy motion on the surface of the jump was created. This motion entrained aluminum oxide film from the surface into aluminum melt. This folded film (so-called "bifilm" defect) was engulfed by the melt and caused its quality to deteriorate. To understand this phenomenon, aluminum casting experiments and computational modeling were conducted. In the casting experiment, a radius ( R j) to the point where the circular hydraulic jump occurred was measured. This is the circular region of `irregular surface feature', a rough oxidized surface texture near the center area of the castings. To quantify contents of the bifilm defects in the outer region of the jump, the samples in this region were sectioned and re-melted for doing re-melted reduced pressure test (re-melt RPT). An "area-normalized" bifilm index map was plotted to analyze bifilms' population in the samples. The flow transition in the hydraulic jump of liquid aluminum depended on three pressure heads: inertial, gravitational, and surface-tension pressures. A new theoretical equation containing surface tension for describing the flow transition of liquid metal was proposed.

  13. RHIC GAMMA TRANSITION JUMP POWER SUPPLY PROTOTYPE TEST.

    SciTech Connect

    MI,J.; GANETIS,G.; LOUIE,W.; BRUNO,D.; ZAPASEK,R.; SANDBERG,J.; ZHANG,W.

    2001-06-18

    This paper describes the principle and test results of the prototype RHIC Gamma Transition Jump Power Supply. The jump power supply principle is introduced and illustrated along with diagrams in this paper. The prototype is built with Insulated Gate Bipolar Transistors (IGBT) as current direction switch components. Optically coupled IGBT drivers are used for the jump control switch. The jump time among the power supplies is synchronized from 40 to 60 milliseconds to meet the RHIC beam transition-crossing requirement. The short jump time is needed to avoid particle loss and to preserve the initial bunch area during the transition, thus successfully transferring the ion beams from the acceleration RF system to storage system. There are a total of twenty four jump power supplies that will be used. They synchronously switch the direction of the magnets current while the beam is being accelerated through the transition to reach the top storage energy. Each power supply will energize a group of super conducting magnets, which consists of four magnets that are connected in series. At the end, test results are listed, accompanied with the dummy load current waveform and prototype power supply picture.

  14. Translocation strategies for multiple species depend on interspecific interaction type.

    PubMed

    Plein, Michaela; Bode, Michael; Moir, Melinda L; Vesk, Peter A

    2016-06-01

    Conservation translocations, anthropogenic movements of species to prevent their extinction, have increased substantially over the last few decades. Although multiple species are frequently moved to the same location, current translocation guidelines consider species in isolation. This practice ignores important interspecific interactions and thereby risks translocation failure. We model three different two-species systems to illustrate the inherent complexity of multispecies translocations and to assess the influence of different interaction types (consumer-resource, mutualism, and competition) on translocation strategies. We focus on how these different interaction types influence the optimal founder population sizes for successful translocations and the order in which the species are moved (simultaneous or sequential). Further, we assess the effect of interaction strength in simultaneous translocations and the time delay between translocations when moving two species sequentially. Our results show that translocation decisions need to reflect the type of interaction. While all translocations of interacting species require a minimum founder population size, which is demarked by an extinction boundary, consumer-resource translocations also have a maximum founder population limit. Above the minimum founder size, increasing the number of translocated individuals leads to a substantial increase in the extinction boundary of competitors and consumers, but not of mutualists. Competitive and consumer-resource systems benefit from sequential translocations, but the order of translocations does not change the outcomes for mutualistic interaction partners noticeably. Interspecific interactions are important processes that shape population dynamics and should therefore be incorporated into the quantitative planning of multispecies translocations. Our findings apply whenever interacting species are moved, for example, in reintroductions, conservation introductions, biological

  15. Force generation examined by laser temperature-jumps in shortening and lengthening mammalian (rabbit psoas) muscle fibres.

    PubMed

    Ranatunga, K W; Coupland, M E; Pinniger, G J; Roots, H; Offer, G W

    2007-11-15

    We examined the tension change induced by a rapid temperature jump (T-jump) in shortening and lengthening active muscle fibres. Experiments were done on segments of permeabilized single fibres (length (L0) approximately 2 mm, sarcomere length 2.5 microm) from rabbit psoas muscle; [MgATP] was 4.6 mm, pH 7.1, ionic strength 200 mm and temperature approximately 9 degrees C. A fibre was maximally Ca2+-activated in the isometric state and a approximately 3 degrees C, rapid (< 0.2 ms), laser T-jump applied when the tension was approximately steady in the isometric state, or during ramp shortening or ramp lengthening at a limited range of velocities (0-0.2 L0 s(-1)). The tension increased to 2- to 3 x P0 (isometric force) during ramp lengthening at velocities > 0.05 L0 s(-1), whereas the tension decreased to about < 0.5 x P0 during shortening at 0.1-0.2 L0 s(-1); the unloaded shortening velocity was approximately 1 L0 s(-1) and the curvature of the force-shortening velocity relation was high (a/P0 ratio from Hill's equation of approximately 0.05). In isometric state, a T-jump induced a tension rise of 15-20% to a new steady state; by curve fitting, the tension rise could be resolved into a fast (phase 2b, 40-50 s(-1)) and a slow (phase 3, 5-10 s(-1)) exponential component (as previously reported). During steady lengthening, a T-jump induced a small instantaneous drop in tension, followed by recovery, so that the final tension recorded with and without a T-jump was not significantly different; thus, a T-jump did not lead to a net increase of tension. During steady shortening, the T-jump induced a pronounced tension rise and both its amplitude and the rate (from a single exponential fit) increased with shortening velocity; at 0.1-0.2 L0 s(-1), the extent of fibre shortening during the T-jump tension rise was estimated to be approximately 1.2% L(0) and it was shorter at lower velocities. At a given shortening velocity and over the temperature range of 8-30 degrees C, the

  16. Force generation examined by laser temperature-jumps in shortening and lengthening mammalian (rabbit psoas) muscle fibres

    PubMed Central

    Ranatunga, K W; Coupland, M E; Pinniger, G J; Roots, H; Offer, G W

    2007-01-01

    We examined the tension change induced by a rapid temperature jump (T-jump) in shortening and lengthening active muscle fibres. Experiments were done on segments of permeabilized single fibres (length (L0) ∼2 mm, sarcomere length 2.5 μm) from rabbit psoas muscle; [MgATP] was 4.6 mm, pH 7.1, ionic strength 200 mm and temperature ∼9°C. A fibre was maximally Ca2+-activated in the isometric state and a ∼3°C, rapid (< 0.2 ms), laser T-jump applied when the tension was approximately steady in the isometric state, or during ramp shortening or ramp lengthening at a limited range of velocities (0–0.2 L0 s−1). The tension increased to 2- to 3 × P0 (isometric force) during ramp lengthening at velocities > 0.05 L0 s−1, whereas the tension decreased to about < 0.5 × P0 during shortening at 0.1–0.2 L0 s−1; the unloaded shortening velocity was ∼1 L0 s−1 and the curvature of the force–shortening velocity relation was high (a/P0 ratio from Hill's equation of ∼0.05). In isometric state, a T-jump induced a tension rise of 15–20% to a new steady state; by curve fitting, the tension rise could be resolved into a fast (phase 2b, 40–50 s−1) and a slow (phase 3, 5–10 s−1) exponential component (as previously reported). During steady lengthening, a T-jump induced a small instantaneous drop in tension, followed by recovery, so that the final tension recorded with and without a T-jump was not significantly different; thus, a T-jump did not lead to a net increase of tension. During steady shortening, the T-jump induced a pronounced tension rise and both its amplitude and the rate (from a single exponential fit) increased with shortening velocity; at 0.1–0.2 L0 s−1, the extent of fibre shortening during the T-jump tension rise was estimated to be ∼1.2% L0 and it was shorter at lower velocities. At a given shortening velocity and over the temperature range of 8–30°C, the rate of T-jump tension rise increased with warming (Q10 ≈ 2.7), similar to

  17. A new approach to polymer translocation

    NASA Astrophysics Data System (ADS)

    Dubbeldam, Johan; Rostiashvili, Vakhtang; Milchev, Andrey; Vilgis, Thomas

    2011-03-01

    Polymer translocation is ubiquitous in nature. It plays a role in phenomena like virus infections and in trafficking of proteins through pores in a cell membrane. Many theoretical models have been developed to explain scaling properties of simple polymer chains through tiny nanopores. This has not resolved the controversies in this field, however. In this paper we employ novel methods to shed light on the results that were obtained using the different models that are in use today. We use, for example fractional Brownian motion to explain the scaling of the variance in the translocation length with time and find good agreement between simulation results and theoretical predictions. An extension of the theory to nanopores with more complex geometries are discussed.

  18. Translocation in the nonpolytrichaceous moss grimmia laevigata

    SciTech Connect

    Alpert, P. )

    1989-10-01

    A superficially rhizomatous habit suggested that the moss Grimmia laevigata might function as a clonal, rhizomatous plant and translocate photoassimilates to below ground organs, even though the species is outside the order Polytrichales, which includes the only mosses known to posses sieve cells. Labelling with {sup 14}CO{sub 2} indicated that at least 10% of newly assimilated carbon was translocated out of leafy shoot portions within 26 hr. Of this carbon, approximately 75% was apparently moved into leafless, basal shoot portions and 25% into below ground stems. Infrared gas analysis of net CO{sup 2} flux was used to check that labelling gave a realistic measure of photosynthesis. Physiological integration and clonal spread may account for the unusual ability of this moss to colonize extremely xeric microsites.

  19. Pore formation and translocation of melittin.

    PubMed Central

    Matsuzaki, K; Yoneyama, S; Miyajima, K

    1997-01-01

    Melittin, a bee venom, is a basic amphiphilic peptide, which mainly acts on the lipid matrix of membranes, lysing various cells. To elucidate the molecular mechanism, we investigated its interactions with phospholipid vesicles. The peptide formed a pore with a short lifetime in the membrane, as revealed by the release of an anionic fluorescent dye, calcein, from the liposomes. Our new double-labeling method clarified that the pore size increased with the peptide-to-lipid ratio. Upon the disintegration of the pore, a fraction of the peptides translocated across the bilayer. The pore formation was coupled with the translocation, which was proved by three fluorescence experiments recently developed by our laboratory. A novel model for the melittin pore formation was discussed in comparison with other pore-forming peptides. PMID:9251799

  20. Origin of translocation barriers for polyelectrolyte chains.

    PubMed

    Kumar, Rajeev; Muthukumar, M

    2009-11-21

    For single-file translocations of a charged macromolecule through a narrow pore, the crucial step of arrival of an end at the pore suffers from free energy barriers, arising from changes in intrachain electrostatic interaction, distribution of ionic clouds and solvent molecules, and conformational entropy of the chain. All contributing factors to the barrier in the initial stage of translocation are evaluated by using the self-consistent field theory for the polyelectrolyte and the coupled Poisson-Boltzmann description for ions without radial symmetry. The barrier is found to be essentially entropic due to conformational changes. For moderate and high salt concentrations, the barriers for the polyelectrolyte chain are quantitatively equivalent to that of uncharged self-avoiding walks. Electrostatic effects are shown to increase the free energy barriers, but only slightly. The degree of ionization, electrostatic interaction strength, decreasing salt concentration, and the solvent quality all result in increases in the barrier. PMID:19929072

  1. A novel selection system for chromosome translocations in Saccharomyces cerevisiae.

    PubMed Central

    Tennyson, Rachel B; Ebran, Nathalie; Herrera, Anissa E; Lindsley, Janet E

    2002-01-01

    Chromosomal translocations are common genetic abnormalities found in both leukemias and solid tumors. While much has been learned about the effects of specific translocations on cell proliferation, much less is known about what causes these chromosome rearrangements. This article describes the development and use of a system that genetically selects for rare translocation events using the yeast Saccharomyces cerevisiae. A translocation YAC was created that contains the breakpoint cluster region from the human MLL gene, a gene frequently involved in translocations in leukemia patients, flanked by positive and negative selection markers. A translocation between the YAC and a yeast chromosome, whose breakpoint falls within the MLL DNA, physically separates the markers and forms the basis for the selection. When RAD52 is deleted, essentially all of the selected and screened cells contain simple translocations. The detectable translocation rates are the same in haploids and diploids, although the mechanisms involved and true translocation rates may be distinct. A unique double-strand break induced within the MLL sequences increases the number of detectable translocation events 100- to 1000-fold. This novel system provides a tractable assay for answering basic mechanistic questions about the development of chromosomal translocations. PMID:11973293

  2. Unforced polymer translocation compared to the forced case.

    PubMed

    Lehtola, V V; Linna, R P; Kaski, K

    2010-03-01

    We present results for unforced polymer translocation from simulations using Langevin dynamics in two dimensions (2D) to four dimensions and stochastic rotation dynamics supporting hydrodynamic modes in three dimensions (3D). We compare our results to forced translocation and a simplified model where the polymer escapes from an infinite pore. The simple model shows that the scaling behavior of unforced translocation is independent of the dimension of the side to which the polymer is translocating. We find that, unlike its forced counterpart, unforced translocation dynamics is insensitive to pore design. Hydrodynamics is seen to markedly speed up the unforced translocation process but not to affect the scaling relations. Average mean-squared displacement shows scaling with average transition time in unforced but not in forced translocation. The waiting-time distribution in unforced translocation follows closely Poissonian distribution. Our measured transfer probabilities align well with those obtained from an equilibrium theory in 3D, but somewhat worse in 2D, where a polymer's relaxation toward equilibrium with respect to its translocation time is slower. Consequently, in stark contrast to forced translocation, unforced translocation is seen to remain close to equilibrium and shows clear universality. PMID:20365761

  3. Translocation and encapsulation of siRNA inside carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Mogurampelly, Santosh; Maiti, Prabal K.

    2013-01-01

    We report spontaneous translocation of small interfering RNA (siRNA) inside carbon nanotubes (CNTs) of various diameters and chirality using all atom molecular dynamics simulations with explicit solvent. We use umbrella sampling method to calculate the free energy landscape of the siRNA entry and translocation event. Free energy profiles show that siRNA gains free energy while translocating inside CNT, and barrier for siRNA exit from CNT ranges from 40 to 110 kcal/mol depending on CNT chirality and salt concentration. The translocation time τ decreases with the increase of CNT diameter with a critical diameter of 24 Å for the translocation. In contrast, double strand DNA of the same sequence does not translocate inside CNT due to large free energy barrier for the translocation. This study helps in understanding the nucleic acid transport through nanopores at microscopic level and may help designing carbon nanotube based sensor for siRNA.

  4. Stepwise translocation of nucleic acid motors

    PubMed Central

    Myong, Sua; Ha, Taekjip

    2010-01-01

    Summary Recent single molecule studies have made a significant contribution to the understanding of the molecular mechanism involved in the movement of motor proteins which process DNA and RNA. Measurement of stepsize in two disparate motors, NS3 helicase and ribosome both revealed three basepair steps which consist of three hidden substeps. Combined with previous structural studies, NS3 is likely taking a single nucleotide step of translocation coupled to one ATP binding event and this mode may be conserved in multitude of helicases. Such a stepwise translocation movement appears to occur through main contacts with the phosphate backbone. Double stranded RNA and DNA motor, RIG-I and Φ29 respectively showed translocation on a duplex while tracking exclusively a single stranded RNA/DNA in a directional manner, 5′ to 3′ in both cases. Spontaneous dynamics displayed by ribosome ratcheting and SSB (single stranded DNA binding protein) diffusing on DNA were rectified by interacting cofactors and proteins, EF-G and RecA respectively. PMID:20061135

  5. Stepwise nucleosome translocation by RSC remodeling complexes.

    PubMed

    Harada, Bryan T; Hwang, William L; Deindl, Sebastian; Chatterjee, Nilanjana; Bartholomew, Blaine; Zhuang, Xiaowei

    2016-01-01

    The SWI/SNF-family remodelers regulate chromatin structure by coupling the free energy from ATP hydrolysis to the repositioning and restructuring of nucleosomes, but how the ATPase activity of these enzymes drives the motion of DNA across the nucleosome remains unclear. Here, we used single-molecule FRET to monitor the remodeling of mononucleosomes by the yeast SWI/SNF remodeler, RSC. We observed that RSC primarily translocates DNA around the nucleosome without substantial displacement of the H2A-H2B dimer. At the sites where DNA enters and exits the nucleosome, the DNA moves largely along or near its canonical wrapping path. The translocation of DNA occurs in a stepwise manner, and at both sites where DNA enters and exits the nucleosome, the step size distributions exhibit a peak at approximately 1-2 bp. These results suggest that the movement of DNA across the nucleosome is likely coupled directly to DNA translocation by the ATPase at its binding site inside the nucleosome. PMID:26895087

  6. Kinetics of C-14 Translocation in Soybean

    PubMed Central

    Fisher, Donald B.

    1970-01-01

    The kinetics of 14C-assimilates in the soybean leaf were studied in pulse labeling and steady state labeling experiments. 14C-Sucrose apparently served as the ultimate source, at least, of translocated 14C-sucrose. However, since the specific activity of leaf sucrose reached a maximum within 5 minutes after pulse labeling, whereas that of exported sucrose did not reach a maximum until at least 20 minutes, it appeared that there were two sucrose compartments in the leaf. A possible physical basis for the two compartments may be the mesophyll (a photosynthetic compartment) and a specialized “paraveinal mesophyll” (a nonphotosynthetic compartment), through which photosynthate must pass on its way to the veins. The 14C kinetics of sterol glucoside, and probably esterified sterol glucoside, were similar to those for 14C-sucrose export. Sterol glucoside was labeled only in its glucose moiety and was the only stem lipid which became strongly labeled during 14C-sucrose translocation. These sterol derivatives may act as membrane carriers of sucrose between the translocation stream and surrounding cells. The kinetics of 14C-sucrose and its movement to the veins are discussed with reference to compartmentation within the leaf and metabolic exchange with other compounds, particularly with starch. Although a simple compartmental model gave a fairly accurate description of 14C-sucrose kinetics, an entirely accurate model could not be provided, primarily because of loss of 14C from sucrose, at an unknown rate, to starch. PMID:16657287

  7. Stepwise nucleosome translocation by RSC remodeling complexes

    PubMed Central

    Harada, Bryan T; Hwang, William L; Deindl, Sebastian; Chatterjee, Nilanjana; Bartholomew, Blaine; Zhuang, Xiaowei

    2016-01-01

    The SWI/SNF-family remodelers regulate chromatin structure by coupling the free energy from ATP hydrolysis to the repositioning and restructuring of nucleosomes, but how the ATPase activity of these enzymes drives the motion of DNA across the nucleosome remains unclear. Here, we used single-molecule FRET to monitor the remodeling of mononucleosomes by the yeast SWI/SNF remodeler, RSC. We observed that RSC primarily translocates DNA around the nucleosome without substantial displacement of the H2A-H2B dimer. At the sites where DNA enters and exits the nucleosome, the DNA moves largely along or near its canonical wrapping path. The translocation of DNA occurs in a stepwise manner, and at both sites where DNA enters and exits the nucleosome, the step size distributions exhibit a peak at approximately 1–2 bp. These results suggest that the movement of DNA across the nucleosome is likely coupled directly to DNA translocation by the ATPase at its binding site inside the nucleosome. DOI: http://dx.doi.org/10.7554/eLife.10051.001 PMID:26895087

  8. Bolaamphiphiles Promote Phospholipid Translocation Across Vesicle Membranes

    PubMed Central

    Forbes, Christopher C.; DiVittorio, Kristy M.; Smith, Bradley D.

    2008-01-01

    A series of membrane-spanning bolaamphiphiles (molecules with two hydrophilic end-groups connected by a hydrophobic linker) were prepared by a modular synthetic method and evaluated for their abilities to affect the dynamics of a surrounding bilayer membrane. The goal was to determine if the bolaamphiphiles promote the translocation of phospholipids across vesicle membranes. The bolaamphiphiles were incorporated at low levels (up to 5 mol%) in vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). Inward translocation assays were performed using fluorescent, NBD-labeled phospholipid probes with phosphocholine (PC) or phosphoglycerol (PG) head-groups. The membrane-spanning bolaamphiphiles promote the translocation of both phospholipid probes in the order PG > PC, while shorter bolaamphiphiles (structures that must adopt a U-shape and keep both end-groups in the same leaflet of the membrane), and regular amphiphiles with one hydrophilic end-group, are inactive. These results are an exception to the rule-of-thumb that membrane-spanning bolaamphiphiles are inherently membrane stabilizing molecules that inhibit all types of membrane transport. PMID:16834395

  9. Force, work and power output of lower limb muscles during human maximal-effort countermovement jumping.

    PubMed

    Nagano, Akinori; Komura, Taku; Fukashiro, Senshi; Himeno, Ryutaro

    2005-08-01

    The purpose of this study was to simulate human maximal-effort countermovement jumping with a three-dimensional neuromusculoskeletal model. The specific aim was to investigate muscle force, work and power output of major lower limb muscles during the motion. A neuromusculoskeletal model that has nine rigid body segments, 20 degrees of freedom, 32 Hill-type lower limb muscles was developed. The neural activation input signal was represented by a series of step functions with step duration of 0.05 s. The excitation-contraction dynamics of the contractile element, the tissues around the joints to limit the joint range of motion, as well as the foot-ground interaction were implemented. A simulation was started from a standing posture. Optimal pattern of the activation input signal was searched through numerical optimization with a goal of maximizing the height reached by the mass center of body after jumping up. As a result, feasible kinematics, ground reaction force profile and muscle excitation profile were generated. It was found that monoarticular muscles had major contributions of mechanical work and power output, whereas biarticular muscles had minor contributions. Hip adductors, abductors and external rotator muscles were vigorously activated, although their mechanical work and power output was minor because of their limited length change during the motion. Joint flexor muscles such as m. iliopsoas, m. biceps femoris short head and m. tibialis anterior were activated in the beginning of the motion with an effect of facilitating the generation of a countermovement. PMID:15811607

  10. Financial Costs of Large Carnivore Translocations – Accounting for Conservation

    PubMed Central

    Weise, Florian J.; Stratford, Ken J.; van Vuuren, Rudolf J.

    2014-01-01

    Human-carnivore conflict continues to present a major conservation challenge around the world. Translocation of large carnivores is widely implemented but remains strongly debated, in part because of a lack of cost transparency. We report detailed translocation costs for three large carnivore species in Namibia and across different translocation scenarios. We consider the effect of various parameters and factors on costs and translocation success. Total translocation cost for 30 individuals in 22 events was $80,681 (US Dollars). Median translocation cost per individual was $2,393, and $2,669 per event. Median cost per cheetah was $2,760 (n = 23), and $2,108 per leopard (n = 6). One hyaena was translocated at a cost of $1,672. Tracking technology was the single biggest cost element (56%), followed by captive holding and feeding. Soft releases, prolonged captivity and orphaned individuals also increased case-specific costs. A substantial proportion (65.4%) of the total translocation cost was successfully recovered from public interest groups. Less than half the translocations were confirmed successes (44.4%, 3 unknown) with a strong species bias. Four leopards (66.7%) were successfully translocated but only eight of the 20 cheetahs (40.0%) with known outcome met these strict criteria. None of the five habituated cheetahs was translocated successfully, nor was the hyaena. We introduce the concept of Individual Conservation Cost (ICC) and define it as the cost of one successfully translocated individual adjusted by costs of unsuccessful events of the same species. The median ICC for cheetah was $6,898 and $3,140 for leopard. Translocations are costly, but we demonstrate that they are not inherently more expensive than other strategies currently employed in non-lethal carnivore conflict management. We conclude that translocation should be one available option for conserving large carnivores, but needs to be critically evaluated on a case-by-case basis. PMID

  11. Financial costs of large carnivore translocations--accounting for conservation.

    PubMed

    Weise, Florian J; Stratford, Ken J; van Vuuren, Rudolf J

    2014-01-01

    Human-carnivore conflict continues to present a major conservation challenge around the world. Translocation of large carnivores is widely implemented but remains strongly debated, in part because of a lack of cost transparency. We report detailed translocation costs for three large carnivore species in Namibia and across different translocation scenarios. We consider the effect of various parameters and factors on costs and translocation success. Total translocation cost for 30 individuals in 22 events was $80,681 (US Dollars). Median translocation cost per individual was $2,393, and $2,669 per event. Median cost per cheetah was $2,760 (n = 23), and $2,108 per leopard (n = 6). One hyaena was translocated at a cost of $1,672. Tracking technology was the single biggest cost element (56%), followed by captive holding and feeding. Soft releases, prolonged captivity and orphaned individuals also increased case-specific costs. A substantial proportion (65.4%) of the total translocation cost was successfully recovered from public interest groups. Less than half the translocations were confirmed successes (44.4%, 3 unknown) with a strong species bias. Four leopards (66.7%) were successfully translocated but only eight of the 20 cheetahs (40.0%) with known outcome met these strict criteria. None of the five habituated cheetahs was translocated successfully, nor was the hyaena. We introduce the concept of Individual Conservation Cost (ICC) and define it as the cost of one successfully translocated individual adjusted by costs of unsuccessful events of the same species. The median ICC for cheetah was $6,898 and $3,140 for leopard. Translocations are costly, but we demonstrate that they are not inherently more expensive than other strategies currently employed in non-lethal carnivore conflict management. We conclude that translocation should be one available option for conserving large carnivores, but needs to be critically evaluated on a case-by-case basis. PMID

  12. Scaling and jumping: gravity loses grip on small jumpers.

    PubMed

    Scholz, Melanie N; Bobbert, Maarten F; Knoek van Soest, A J

    2006-06-21

    There are several ways to quantify jumping performance, a common definition being the height gained by the body's centre of mass (CM) in the airborne phase. Under this definition, jump height is determined by take-off velocity. According to the existing literature on jumping and scaling, take-off velocity, and hence jumping performance is independent of size because the energy that differently sized geometrically scaled jumpers can generate with their muscles is proportional to their mass. In this article it is shown, based on a simple energy balance, that it is incorrect to presume that jump height does not depend on size. Contrary to common belief, size as such has does have an effect on take-off velocity, putting small jumpers at a mechanical advantage, as is shown analytically. To quantify the effect of size on take-off velocity, a generic jumper model was scaled geometrically and evaluated numerically. While a 70-kg jumper took off at 2.65 m/s and raised its CM by 0.36 m after take-off, a perfectly geometrically similar jumper of 0.7 g reached a take-off velocity of 3.46 m/s and raised its CM by 0.61 m. The reason for the better performance of small jumpers is their higher efficacy in transforming the energy generated by the actuators into energy due to vertical velocity of the CM. Considering the ecological and evolutionary relevance of different definitions of jump height, size-dependent efficacy might explain why habitual jumping is especially prominent among small animals such as insects. PMID:16332377

  13. Jumping mechanisms and performance of pygmy mole crickets (Orthoptera, Tridactylidae).

    PubMed

    Burrows, M; Picker, M D

    2010-07-15

    Pygmy mole crickets live in burrows at the edge of water and jump powerfully to avoid predators such as the larvae and adults of tiger beetles that inhabit the same microhabitat. Adults are 5-6 mm long and weigh 8 mg. The hind legs are dominated by enormous femora containing the jumping muscles and are 131% longer than the body. The ratio of leg lengths is: 1:2.1:4.5 (front:middle:hind, respectively). The hind tarsi are reduced and their role is supplanted by two pairs of tibial spurs that can rotate through 180 deg. During horizontal walking the hind legs are normally held off the ground. Jumps are propelled by extension of the hind tibiae about the femora at angular velocities of 68,000 deg s(-1) in 2.2 ms, as revealed by images captured at rates of 5000 s(-1). The two hind legs usually move together but can move asynchronously, and many jumps are propelled by just one hind leg. The take-off angle is steep and once airborne the body rotates backwards about its transverse axis (pitch) at rates of 100 Hz or higher. The take-off velocity, used to define the best jumps, can reach 5.4 m s(-1), propelling the insect to heights of 700 mm and distances of 1420 mm with an acceleration of 306 g. The head and pronotum are jerked rapidly as the body is accelerated. Jumping on average uses 116 microJ of energy, requires a power output of 50 mW and exerts a force of 20 mN. In jumps powered by one hind leg the figures are about 40% less. PMID:20581268

  14. Dynamic rupture processes on two orthogonal but not conjugate fault segments

    NASA Astrophysics Data System (ADS)

    Kase, Y.; Aoi, S.

    2010-12-01

    The 2009 Suruga-bay, Japan, earthquake was supposed to rupture two orthogonal but not conjugate fault segments. The aftershock distribution consisting of two planes, which has the SE- and NE-dipping planes for the southern and northern source areas, respectively, and the hypocenter of the main shock was located at the SE-dipping plane (Aoi et al., 2010, Nature geoscience). The normal vectors of the two planes are almost orthogonal. Using the fault plane model that consists of the SE-dipping fault segment with a hypocenter and the NE-dipping fault segment connecting with the other segment at the point 5 km west of the hypocenter, Aoi et al. (2010) estimated the rupture process using the near-source strong-motion data. The estimated rake angles suggested that the SE-dipping fault segment had right-lateral strike slip, and that the NE-dipping segment had reverse slip. In this study, we investigate a physical possibility of coseismic slip on two orthogonal but not conjugate fault segments, using dynamic rupture simulations. The 3-D finite-difference method of Kase and Kuge (2001, GJI) is modified for an infinite medium. Varying the geometry of two faults and the maximum compressional stress axis, we calculate spontaneous rupture processes on segments, and examine whether a rupture propagating to the joint can jump to the second segment. Assuming coefficients of friction to be uniform on the two faults, we estimate the ranges of azimuth and plunge using rake angle on the first (SE-dipping) segment and stress condition on the second (NE-dipping) segment, respectively. Results of spontaneous rupture simulations show that a rupture triggered on the second segment successfully propagates only when strength excess is smaller and stress drop is larger on the second segment than the first segment. The conditions of the stress and dynamic parameters for successful rupture jump and propagation on the second segment are very limited. When the rupture extends on the both segments

  15. Determination of K-shell absorption jump factors and jump ratios for La2O3, Ce and Gd using two different methods

    NASA Astrophysics Data System (ADS)

    Akman, Ferdi; Durak, Rıdvan; Kaçal, Mustafa Recep; Turhan, Mehmet Fatih; Akdemir, Fatma

    2015-02-01

    The K shell absorption jump factors and jump ratios for La2O3, Ce and Gd samples have been determined using the gamma or X-ray attenuation and EDXRF methods. It is the first time that the K shell absorption jump factor and jump ratio have been discussed for present elements using two different methods. To detect K X-rays, a high resolution Si(Li) detector was used. The experimental results of K shell absorption jump factors and jump ratios were compared with the theoretically calculated ones.

  16. Pancreas and cyst segmentation

    NASA Astrophysics Data System (ADS)

    Dmitriev, Konstantin; Gutenko, Ievgeniia; Nadeem, Saad; Kaufman, Arie

    2016-03-01

    Accurate segmentation of abdominal organs from medical images is an essential part of surgical planning and computer-aided disease diagnosis. Many existing algorithms are specialized for the segmentation of healthy organs. Cystic pancreas segmentation is especially challenging due to its low contrast boundaries, variability in shape, location and the stage of the pancreatic cancer. We present a semi-automatic segmentation algorithm for pancreata with cysts. In contrast to existing automatic segmentation approaches for healthy pancreas segmentation which are amenable to atlas/statistical shape approaches, a pancreas with cysts can have even higher variability with respect to the shape of the pancreas due to the size and shape of the cyst(s). Hence, fine results are better attained with semi-automatic steerable approaches. We use a novel combination of random walker and region growing approaches to delineate the boundaries of the pancreas and cysts with respective best Dice coefficients of 85.1% and 86.7%, and respective best volumetric overlap errors of 26.0% and 23.5%. Results show that the proposed algorithm for pancreas and pancreatic cyst segmentation is accurate and stable.

  17. A novel T-DNA integration in rice involving two interchromosomal translocations.

    PubMed

    Majhi, Bharat Bhusan; Shah, Jasmine M; Veluthambi, Karuppannan

    2014-06-01

    A male sterile transgenic rice plant TC-19 harboured a novel T-DNA integration in chromosome 8 with two interchromosomal translocations of 6.55 kb chromosome 3 and 29.8 kb chromosome 9 segments. We report a complex Agrobacterium T-DNA integration in rice (Oryza sativa) associated with two interchromosomal translocations. The T-DNA-tagged rice mutant TC-19, which harboured a single copy of the T-DNA, displayed male sterile phenotype in the homozygous condition. Analysis of the junctions between the T-DNA ends and the rice genome by genome walking showed that the right border is flanked by a chromosome 3 sequence and the left border is flanked by a chromosome 9 sequence. Upon further walking on chromosome 3, a chromosome 3/chromosome 8 fusion was detected. Genome walking from the opposite end of the chromosome 8 break point revealed a chromosome 8/chromosome 9 fusion. Our findings revealed that the T-DNA, together with a 6.55-kb region of chromosome 3 and a 29.8-kb region of chromosome 9, was translocated to chromosome 8. Southern blot analysis of the homozygous TC-19 mutant revealed that the native sequences of chromosome 3 and 9 were restored but the disruption of chromosome 8 in the first intron of the gene Os08g0152500 was not restored. The integration of the complex T-DNA in chromosome 8 caused male sterility. PMID:24487649

  18. Ion Conductance of the Stem of the Anthrax Toxin Channel during Lethal Factor Translocation

    PubMed Central

    Schiffmiller, Aviva; Finkelstein, Alan

    2014-01-01

    The tripartite anthrax toxin consists of protective antigen (PA), lethal factor (LF), and edema factor (EF). PA63 (the 63 kDa, C-terminal part of PA) forms heptameric channels in cell membranes that allow for the transport of LF and EF into the cytosol. These channels are mushroom-shaped, with a ring of seven phenylalanine residues (known as the phenylalanine clamp) lining the junction between the cap and stem. It is known that when LF is translocated through the channel, the phenylalanine clamp creates a seal that causes an essentially complete block of conduction. In order to examine ion conductance in the stem of the channel, we used Venus yellow fluorescent protein (YFP) as a molecular stopper to trap LFN (the 30 kDa, 263-residue N-terminal segment of LF), and various truncated constructs of LFN, in mutant channels in which the phenylalanine clamp residues were mutated to alanines. Here we present evidence that ion movement occurs within the channel stem (but is stopped, of course, at the phenylalanine clamp) during protein translocation. Furthermore, we also propose that the lower region of the stem plays an important role in securing peptide chains during translocation. PMID:24996036

  19. Stoichiometry of proton translocation by respiratory complex I and its mechanistic implications

    PubMed Central

    Wikström, Mårten; Hummer, Gerhard

    2012-01-01

    Complex I (NADH-ubiquinone oxidoreductase) in the respiratory chain of mitochondria and several bacteria functions as a redox-driven proton pump that contributes to the generation of the protonmotive force across the inner mitochondrial or bacterial membrane and thus to the aerobic synthesis of ATP. The stoichiometry of proton translocation is thought to be 4 H+ per NADH oxidized (2 e-). Here we show that a H+/2 e- ratio of 3 appears more likely on the basis of the recently determined H+/ATP ratio of the mitochondrial F1Fo-ATP synthase of animal mitochondria and of a set of carefully determined ATP/2 e- ratios for different segments of the mitochondrial respiratory chain. This lower H+/2 e- ratio of 3 is independently supported by thermodynamic analyses of experiments with both mitochondria and submitochondrial particles. A reduced H+/2 e- stoichiometry of 3 has important mechanistic implications for this proton pump. In a rough mechanistic model, we suggest a concerted proton translocation mechanism in the three homologous and tightly packed antiporter-like subunits L, M, and N of the proton-translocating membrane domain of complex I. PMID:22392981

  20. Barriers, pathways and processes for uptake, translocation and accumulation of nanomaterials in plants--Critical review.

    PubMed

    Schwab, Fabienne; Zhai, Guangshu; Kern, Meaghan; Turner, Amalia; Schnoor, Jerald L; Wiesner, Mark R

    2016-01-01

    Uptake, transport and toxicity of engineered nanomaterials (ENMs) into plant cells are complex processes that are currently still not well understood. Parts of this problem are the multifaceted plant anatomy, and analytical challenges to visualize and quantify ENMs in plants. We critically reviewed the currently known ENM uptake, translocation, and accumulation processes in plants. A vast number of studies showed uptake, clogging, or translocation in the apoplast of plants, most notably of nanoparticles with diameters much larger than the commonly assumed size exclusion limit of the cell walls of ∼5-20 nm. Plants that tended to translocate less ENMs were those with low transpiration, drought-tolerance, tough cell wall architecture, and tall growth. In the absence of toxicity, accumulation was often linearly proportional to exposure concentration. Further important factors strongly affecting ENM internalization are the cell wall composition, mucilage, symbiotic microorganisms (mycorrhiza), the absence of a cuticle (submerged plants) and stomata aperture. Mostly unexplored are the roles of root hairs, leaf repellency, pit membrane porosity, xylem segmentation, wounding, lateral roots, nodes, the Casparian band, hydathodes, lenticels and trichomes. The next steps towards a realistic risk assessment of nanoparticles in plants are to measure ENM uptake rates, the size exclusion limit of the apoplast and to unravel plant physiological features favoring uptake. PMID:26067571

  1. Photosynthesis, respiration and translocation in green fruit of normal and mutant grapefruit. [Citrus paradisi Macf

    SciTech Connect

    Koch, K.E.; Yen, C.R.; Avigne, W.T.

    1986-04-01

    Gas exchange, /sup 14/CO/sub 2/ fixation/and subsequent photosynthate translocation were followed during a 24h light/dark period in green grapefruit (Citrus paradisi Macf.) detached after 2.5 mo. growth. Fruit photosynthesis could account for net fixation of less than 1% of the daily dry weight increase recorded for fruit at this stage of development, but a comparison of light/dark CO/sub 2/ exchange indicated that as much as 27% of this daily gain was maintained by refixation of respiratory CO/sub 2/ during daylight hours. Approximately 10% of photosynthates labeled in the outer peel (flavedo) were translocated to segment epidermis and juice vesicles of normal fruit during 1 + 23h pulse-chase experiments. This process typically continues for 4 to 5 days and refixation products would presumably follow the same path. In a low-acid mutant believed to differ only in acid/sugar ratio of juice vesicles, however, inward translocation of /sup 14/C-photosynthates from flavedo was restricted primarily to the inner peel (albedo).

  2. Cooperation of TOM and TIM23 complexes during translocation of proteins into mitochondria.

    PubMed

    Waegemann, Karin; Popov-Čeleketić, Dušan; Neupert, Walter; Azem, Abdussalam; Mokranjac, Dejana

    2015-03-13

    Translocation of the majority of mitochondrial proteins from the cytosol into mitochondria requires the cooperation of TOM and TIM23 complexes in the outer and inner mitochondrial membranes. The molecular mechanisms underlying this cooperation remain largely unknown. Here, we present biochemical and genetic evidence that at least two contacts from the side of the TIM23 complex play an important role in TOM-TIM23 cooperation in vivo. Tim50, likely through its very C-terminal segment, interacts with Tom22. This interaction is stimulated by translocating proteins and is independent of any other TOM-TIM23 contact known so far. Furthermore, the exposure of Tim23 on the mitochondrial surface depends not only on its interaction with Tim50 but also on the dynamics of the TOM complex. Destabilization of the individual contacts reduces the efficiency of import of proteins into mitochondria and destabilization of both contacts simultaneously is not tolerated by yeast cells. We conclude that an intricate and coordinated network of protein-protein interactions involving primarily Tim50 and also Tim23 is required for efficient translocation of proteins across both mitochondrial membranes. PMID:25083920

  3. Jump point detection for real estate investment success

    NASA Astrophysics Data System (ADS)

    Hui, Eddie C. M.; Yu, Carisa K. W.; Ip, Wai-Cheung

    2010-03-01

    In the literature, studies on real estate market were mainly concentrating on the relation between property price and some key factors. The trend of the real estate market is a major concern. It is believed that changes in trend are signified by some jump points in the property price series. Identifying such jump points reveals important findings that enable policy-makers to look forward. However, not all jump points are observable from the plot of the series. This paper looks into the trend and introduces a new approach to the framework for real estate investment success. The main purpose of this paper is to detect jump points in the time series of some housing price indices and stock price index in Hong Kong by applying the wavelet analysis. The detected jump points reflect to some significant political issues and economic collapse. Moreover, the relations among properties of different classes and between stocks and properties are examined. It can be shown from the empirical result that a lead-lag effect happened between the prices of large-size property and those of small/medium-size property. However, there is no apparent relation or consistent lead in terms of change point measure between property price and stock price. This may be due to the fact that globalization effect has more impact on the stock price than the property price.

  4. Mechanical parameters and flight phase characteristics in aquatic plyometric jumping.

    PubMed

    Louder, Talin J; Searle, Cade J; Bressel, Eadric

    2016-09-01

    Plyometric jumping is a commonly prescribed method of training focused on the development of reactive strength and high-velocity concentric power. Literature suggests that aquatic plyometric training may be a low-impact, effective supplement to land-based training. The purpose of the present study was to quantify acute, biomechanical characteristics of the take-off and flight phase for plyometric movements performed in the water. Kinetic force platform data from 12 young, male adults were collected for counter-movement jumps performed on land and in water at two different immersion depths. The specificity of jumps between environmental conditions was assessed using kinetic measures, temporal characteristics, and an assessment of the statistical relationship between take-off velocity and time in the air. Greater peak mechanical power was observed for jumps performed in the water, and was influenced by immersion depth. Additionally, the data suggest that, in the water, the statistical relationship between take-off velocity and time in air is quadratic. Results highlight the potential application of aquatic plyometric training as a cross-training tool for improving mechanical power and suggest that water immersion depth and fluid drag play key roles in the specificity of the take-off phase for jumping movements performed in the water. PMID:27125295

  5. Jumping to conclusions and paranoid ideation in the general population.

    PubMed

    Freeman, Daniel; Pugh, Katherine; Garety, Philippa

    2008-07-01

    An association of a 'jumping to conclusions' (JTC) reasoning style and delusions has been repeatedly found. The data-gathering bias has been particularly implicated with higher levels of delusional conviction in schizophrenia. For the first time the symptom, psychological and social correlates of jumping to conclusions are examined in a large general population sample. This is based upon the recognition that delusional ideation in non-clinical populations is on a continuum of severity with delusions in psychosis. Two hundred individuals completed a probabilistic reasoning task and assessments of paranoid ideation, intellectual functioning, affective symptoms, anomalies of experience, cognitive flexibility, illicit drug use, social support, and trauma. The jumping to conclusions reasoning bias was found in 20% of the non-clinical sample. JTC was strongly associated with higher levels of conviction in paranoid thoughts and the occurrence of perceptual anomalies, but not with the presence of affective symptoms. The results indicate that jumping to conclusions is a reasoning bias specifically associated with levels of delusional conviction, and is not a product of generally high levels of distress and affect. The association of jumping to conclusions with the types of anomalies of experience seen in psychotic disorders is intriguing, and consistent with recent dopamine dysregulation theories and the importance of reasoning to perception. The study is a further illustration of the need to consider the dimensions of delusional experience separately. PMID:18442898

  6. Anticipating the Species Jump: Surveillance for Emerging Viral Threats

    PubMed Central

    Flanagan, M. L.; Parrish, C. R.; Cobey, S.; Glass, G. E.; Bush, R. M.; Leighton, T. J.

    2016-01-01

    Summary Zoonotic disease surveillance is typically triggered after animal pathogens have already infected humans. Are there ways to identify high-risk viruses before they emerge in humans? If so, then how and where can identifications be made and by what methods? These were the fundamental questions driving a workshop to examine the future of predictive surveillance for viruses that might jump from animals to infect humans. Virologists, ecologists and computational biologists from academia, federal government and non-governmental organizations discussed opportunities as well as obstacles to the prediction of species jumps using genetic and ecological data from viruses and their hosts, vectors and reservoirs. This workshop marked an important first step towards envisioning both scientific and organizational frameworks for this future capability. Canine parvoviruses as well as seasonal H3N2 and pandemic H1N1 influenza viruses are discussed as exemplars that suggest what to look for in anticipating species jumps. To answer the question of where to look, prospects for discovering emerging viruses among wildlife, bats, rodents, arthropod vectors and occupationally exposed humans are discussed. Finally, opportunities and obstacles are identified and accompanied by suggestions for how to look for species jumps. Taken together, these findings constitute the beginnings of a conceptual framework for achieving a virus surveillance capability that could predict future species jumps. PMID:21914152

  7. Bayesian inference for Markov jump processes with informative observations.

    PubMed

    Golightly, Andrew; Wilkinson, Darren J

    2015-04-01

    In this paper we consider the problem of parameter inference for Markov jump process (MJP) representations of stochastic kinetic models. Since transition probabilities are intractable for most processes of interest yet forward simulation is straightforward, Bayesian inference typically proceeds through computationally intensive methods such as (particle) MCMC. Such methods ostensibly require the ability to simulate trajectories from the conditioned jump process. When observations are highly informative, use of the forward simulator is likely to be inefficient and may even preclude an exact (simulation based) analysis. We therefore propose three methods for improving the efficiency of simulating conditioned jump processes. A conditioned hazard is derived based on an approximation to the jump process, and used to generate end-point conditioned trajectories for use inside an importance sampling algorithm. We also adapt a recently proposed sequential Monte Carlo scheme to our problem. Essentially, trajectories are reweighted at a set of intermediate time points, with more weight assigned to trajectories that are consistent with the next observation. We consider two implementations of this approach, based on two continuous approximations of the MJP. We compare these constructs for a simple tractable jump process before using them to perform inference for a Lotka-Volterra system. The best performing construct is used to infer the parameters governing a simple model of motility regulation in Bacillus subtilis. PMID:25720091

  8. Segmented ion thruster

    NASA Technical Reports Server (NTRS)

    Brophy, John R. (Inventor)

    1993-01-01

    Apparatus and methods for large-area, high-power ion engines comprise dividing a single engine into a combination of smaller discharge chambers (or segments) configured to operate as a single large-area engine. This segmented ion thruster (SIT) approach enables the development of 100-kW class argon ion engines for operation at a specific impulse of 10,000 s. A combination of six 30-cm diameter ion chambers operating as a single engine can process over 100 kW. Such a segmented ion engine can be operated from a single power processor unit.

  9. Measurement of background translocation frequencies in individuals with clones

    SciTech Connect

    Wade, M.J.

    1996-08-01

    In the leukemia case the unseparated B and T lymphocytes had a high translocation frequency even after 0.0014, respectively. After purging all clones from the data, the translocation frequencies for Bio 8 and Bio 23 were 0.00750.0014 and 0.0073 metaphases were scored for chromosomal aberrations,, specifically reciprocal translocations, using fluorescence in situ hybridization (FISH). Metaphase spreads were used from two healthy, unexposed individuals (not exposed to radiation, chemotherapy or radiotherapy) and one early B- precursor acute lymphocytic leukemia (ALL) patient (metaphase spreads from both separated T lymphocytes and unseparated B and T lymphocytes were scored). All three individuals had an abnormally high translocation frequency. The high translocation frequencies resulted from clonal expansion of specific translocated chromosomes. I show in this thesis that by purging (discounting or removing) clones from the data of unexposed individuals, one can obtain true background translocation frequencies. In two cases, Bio 8 and Bio 23, the measured translocation frequency for chromosomes 1, 2 and 4 was 0.0124 purging all of the clones from the data. This high translocation frequency may be due to a low frequency of some clones and may not be recognized. The separated T lymphocytes had a higher translocation frequency than expected.

  10. Image segmentation survey

    NASA Technical Reports Server (NTRS)

    Haralick, R. M.

    1982-01-01

    The methodologies and capabilities of image segmentation techniques are reviewed. Single linkage schemes, hybrid linkage schemes, centroid linkage schemes, histogram mode seeking, spatial clustering, and split and merge schemes are addressed.

  11. Segmentation of SAR images

    NASA Technical Reports Server (NTRS)

    Kwok, Ronald

    1989-01-01

    The statistical characteristics of image speckle are reviewed. Existing segmentation techniques that have been used for speckle filtering, edge detection, and texture extraction are sumamrized. The relative effectiveness of each technique is briefly discussed.

  12. Multiple Tune Jumps to Overcome Horizontal Depolarizing Resonances

    NASA Astrophysics Data System (ADS)

    Huang, H.; Ahrens, L. A.; Bai, M.; Brown, K. A.; Dutheil, Y.; Gardner, C.; Glenn, J. W.; Lin, F.; Mackay, W. W.; Meot, F.; Poblaguev, A.; Ranjbar, V.; Roser, T.; Schoefer, V.; Tepikian, S.; Tsoupas, N.; Yip, K.; Zelenski, A.; Zeno, K.

    2016-02-01

    Imperfection and vertical intrinsic depolarizing resonances have been overcome by the two partial Siberian snakes in the Alternative Gradient Synchrotron(AGS). The relatively weak but numerous horizontal resonances are the main source of polarization loss in the AGS. A pair of horizontal tune jump quads have been used to overcome these weak resonances. The locations of the two quads have to be chosen such that the disturbance to the beam optics is minimum. The emittance growth has to be mitigated for this method to work. In addition, this technique needs very accurate jump timing. Using two partial Siberian snakes, with vertical tune inside the spin tune gap and 80% polarization at AGS injection, polarized proton beam had reached 1.5 × 1011 proton per bunch with 65% polarization. With the tune jump timing optimized and emittance preserved, more than 70% polarization with 2 × 1011 protons per bunch has been achieved.

  13. Two-level parabolic model with phase-jump coupling

    NASA Astrophysics Data System (ADS)

    Lehto, J. M. S.; Suominen, K.-A.

    2016-07-01

    We study the coherent dynamics of a two-level parabolic model and ways to enhance population transfer and even to obtain complete population inversion in such models. Motivated by the complete population inversion effect of zero-area pulses found in [Phys. Rev. A 73, 023416 (2006), 10.1103/PhysRevA.73.023416], we consider a scheme where a given coupling function is transformed to a zero-area coupling by performing a phase jump in the middle of the evolution. With a phase-jump coupling, complete population inversion can be achieved with relatively small coupling. In the case of Zener tunneling, complete population inversion is obtained for strong-enough coupling regardless of the height of the tunneling barrier. We also derive a universal formula for the effect of the phase jump.

  14. AGS tune jump power supply design and test

    SciTech Connect

    Mi, J.; Glenn, J.W.; Huang, H.; Marneris, I.; Rosas, P.; Sandberg, J.; Tan, Y.; Zhang, W.

    2011-03-28

    A horizontal tune jump system has been installed to overcome the horizontal intrinsic spin resonances, which requires jumping the horizontal tune 0.04 units 82 times, 41 up and 41 down. Two quadruple magnets have been installed in AGS ring to perform this. The pulsed magnet current ranges from about 140A near injection to about 1400A later. The current pulse rise and fall time are around 100uS and flat tops time is around 4mS. These quadruples have separated supplies. This tune jump pulse power supply employees all semiconductor parts as well as the main switches. During dummy load and magnet testing, the test results showed that the power supply could meet the specification. This article will describe some details of power supply simulation, design and testing. Some test waveforms and pictures are presented in this paper.

  15. Basketball jump shooting is controlled online by vision.

    PubMed

    de Oliveira, R Ferraz; Huys, R; Oudejans, R R D; van de Langenberg, R; Beek, P J

    2007-01-01

    An experiment was conducted to examine whether basketball jump shooting relies on online visual (i.e., dorsal stream-mediated) control rather than motor preprogramming. Seventeen expert basketball players (eight males and nine females) performed jump shots under normal vision and in three conditions in which movement initiation was delayed by zero, one, or two seconds relative to viewing the basket. Shots were evaluated in terms of both outcome and execution measures. Even though most shots still landed near the basket in the absence of vision, end-point accuracy was significantly better under normal visual conditions than under the delay conditions, where players tended to undershoot the basket. In addition, an overall decrease of inter-joint coordination strength and stability was found as a function of visual condition. Although these results do not exclude a role of motor preprogramming, they demonstrate that visual sensory information plays an important role in the continuous guidance of the basketball jump shot. PMID:17725158

  16. Effect of oral creatine supplementation on jumping and running performance.

    PubMed

    Bosco, C; Tihanyi, J; Pucspk, J; Kovacs, I; Gabossy, A; Colli, R; Pulvirenti, G; Tranquilli, C; Foti, C; Viru, M; Viru, A

    1997-07-01

    The study was designed to investigate the effect of creatine monohydrate ingestion (20 g daily for 5 days) on performance in 45 s maximal continuous jumping and in all-out treadmill running at 20 km x h(-1), (inclination 5 degrees, duration approximately 60s). The participants were qualified sprinters and jumpers. The effect of creatine was compared with placebo in a double-blind design. Creatine (Cr) supplementation led to a significant enhancement of performance capacity in the jumping test by 7% during the first 15 s and by 12% during the second 15 s of the exercise. The positive effect of Cr supplementation was not observed in the last third of the continuous jumping exercise, when the contribution of anaerobic metabolism was decreasing. The time of intensive running up to exhaustion improved by 13%. The results show that Cr supplementation helps to prolong the time during which the maximal rate of power output could be maintained. PMID:9298778

  17. Trisomy 7p resulting from isochromosome formation and whole-arm translocation

    SciTech Connect

    Lurie, I.W.; Cohen, M.M.C.; Schwartz, M.F.

    1995-01-02

    A newborn boy with a large anterior fontanel, minor facial anomalies, postaxial polydactyly, patent ductus arteriosus, and developmental delay had trisomy of 7p due to an i(7p) and a concomitant t(2;7) (q37.3; q11.1). Significant enlargement of the fontanel is the most characteristic finding in most patients with duplications involving 7p15-pter. Asynchrony in fore- and hind-brain and hemisphere formation leading to brain asymmetry and various defects in the posterior fossa are typical of infants with duplications of 7p11-p12. A variety of heart defects has also been found in more than 50% of patients with duplication of 7p segments. Isochromosome formation accompanied by whole-arm translocation, resulting in uniparental isodisomy for the involved segment, is an extremely rare cause leading to partial trisomies. Although it is not clear whether isochromosome formation precedes the whole-arm translocation or follows it, the secondary rearrangement may have adaptive significance. 46 refs., 2 figs., 3 tabs.

  18. Meiotic segregation of five different reciprocal translocations in the onion fly, Hylemya antiqua (Meigen).

    PubMed

    Vosselman, L

    1981-01-01

    For one translocation (T14) with short interstitial segments in Hylemya antiqua significant differences in segregation behaviour between males and females were observed. In males the ratio of alternate:adjacent 1:adjacent 2 was approximately 7:3:0 and in females about 8:1:3. This difference is attributed to the difference in type of chromosome association. Female meiosis is chiasmate and male meiosis is achiasmate. It is suggested that meiotic pairing in males results in relative short "Coorientation Determining Distances" (CDDs) between homologous centromeres which favours alternate and adjacent 1 segregation. In females because of non-localized chiasmata on the average no differences in CDD between homologous and nonhomologous centromeres are expected. This might explain the occurrence of coorientation between non-homologous centromeres resulting in adjacent 2 segregations. Four other translocations with longer interstitial segments than T14 showed in males as well as females predominantly an alternate and adjacent 1 segregation, adjacent 2 was hardly found (0-3.6%). The longer distance between non-homologous centromeres is probably the reason. PMID:7472022

  19. Adjacent segment disease.

    PubMed

    Virk, Sohrab S; Niedermeier, Steven; Yu, Elizabeth; Khan, Safdar N

    2014-08-01

    EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Understand the forces that predispose adjacent cervical segments to degeneration. 2. Understand the challenges of radiographic evaluation in the diagnosis of cervical and lumbar adjacent segment disease. 3. Describe the changes in biomechanical forces applied to adjacent segments of lumbar vertebrae with fusion. 4. Know the risk factors for adjacent segment disease in spinal fusion. Adjacent segment disease (ASD) is a broad term encompassing many complications of spinal fusion, including listhesis, instability, herniated nucleus pulposus, stenosis, hypertrophic facet arthritis, scoliosis, and vertebral compression fracture. The area of the cervical spine where most fusions occur (C3-C7) is adjacent to a highly mobile upper cervical region, and this contributes to the biomechanical stress put on the adjacent cervical segments postfusion. Studies have shown that after fusion surgery, there is increased load on adjacent segments. Definitive treatment of ASD is a topic of continuing research, but in general, treatment choices are dictated by patient age and degree of debilitation. Investigators have also studied the risk factors associated with spinal fusion that may predispose certain patients to ASD postfusion, and these data are invaluable for properly counseling patients considering spinal fusion surgery. Biomechanical studies have confirmed the added stress on adjacent segments in the cervical and lumbar spine. The diagnosis of cervical ASD is complicated given the imprecise correlation of radiographic and clinical findings. Although radiological and clinical diagnoses do not always correlate, radiographs and clinical examination dictate how a patient with prolonged pain is treated. Options for both cervical and lumbar spine ASD include fusion and/or decompression. Current studies are encouraging regarding the adoption of arthroplasty in spinal surgery, but more long

  20. Segmented pyroelector detector

    DOEpatents

    Stotlar, S.C.; McLellan, E.J.

    1981-01-21

    A pyroelectric detector is described which has increased voltage output and improved responsivity over equivalent size detectors. The device comprises a plurality of edge-type pyroelectric detectors which have a length which is much greater than the width of the segments between the edge-type electrodes. External circuitry connects the pyroelectric detector segments in parallel to provide a single output which maintains 50 ohm impedance characteristics.

  1. Squaring a Circular Segment

    ERIC Educational Resources Information Center

    Gordon, Russell

    2008-01-01

    Consider a circular segment (the smaller portion of a circle cut off by one of its chords) with chord length c and height h (the greatest distance from a point on the arc of the circle to the chord). Is there a simple formula involving c and h that can be used to closely approximate the area of this circular segment? Ancient Chinese and Egyptian…

  2. AirJump: Using Interfaces to Instantly Perform Simultaneous Extractions.

    PubMed

    Berry, Scott M; Pezzi, Hannah M; LaVanway, Alex J; Guckenberger, David J; Anderson, Meghan A; Beebe, David J

    2016-06-22

    Analyte isolation is an important process that spans a range of biomedical disciplines, including diagnostics, research, and forensics. While downstream analytical techniques have advanced in terms of both capability and throughput, analyte isolation technology has lagged behind, increasingly becoming the bottleneck in these processes. Thus, there exists a need for simple, fast, and easy to integrate analyte separation protocols to alleviate this bottleneck. Recently, a new class of technologies has emerged that leverages the movement of paramagnetic particle (PMP)-bound analytes through phase barriers to achieve a high efficiency separation in a single or a few steps. Specifically, the passage of a PMP/analyte aggregate through a phase interface (aqueous/air in this case) acts to efficiently "exclude" unbound (contaminant) material from PMP-bound analytes with higher efficiency than traditional washing-based solid-phase extraction (SPE) protocols (i.e., bind, wash several times, elute). Here, we describe for the first time a new type of "exclusion-based" sample preparation, which we term "AirJump". Upon realizing that much of the contaminant carryover stems from interactions with the sample vessel surface (e.g., pipetting residue, wetting), we aim to eliminate the influence of that factor. Thus, AirJump isolates PMP-bound analyte by "jumping" analyte directly out of a free liquid/air interface. Through careful characterization, we have demonstrated the validity of AirJump isolation through comparison to traditional washing-based isolations. Additionally, we have confirmed the suitability of AirJump in three important independent biological isolations, including protein immunoprecipitation, viral RNA isolation, and cell culture gene expression analysis. Taken together, these data sets demonstrate that AirJump performs efficiently, with high analyte yield, high purity, no cross contamination, rapid time-to-isolation, and excellent reproducibility. PMID:27249333

  3. Segmental neurofibromatosis and malignancy.

    PubMed

    Dang, Julie D; Cohen, Philip R

    2010-01-01

    Segmental neurofibromatosis is an uncommon variant of neurofibromatosis type I characterized by neurofibromas and/or café-au-lait macules localized to one sector of the body. Although patients with neurofibromatosis type I have an associated increased risk of certain malignancies, malignancy has only occasionally been reported in patients with segmental neurofibromatosis. The published reports of patients with segmental neurofibromatosis who developed malignancy were reviewed and the characteristics of these patients and their cancers were summarized. Ten individuals (6 women and 4 men) with segmental neurofibromatosis and malignancy have been reported. The malignancies include malignant peripheral nerve sheath tumor (3), malignant melanoma (2), breast cancer (1), colon cancer (1), gastric cancer (1), lung cancer (1), and Hodgkin lymphoma (1). The most common malignancies in patients with segmental neurofibromatosis are derived from neural crest cells: malignant peripheral nerve sheath tumor and malignant melanoma. The incidence of malignancy in patients with segmental neurofibromatosis may approach that of patients with neurofibromatosis type I. PMID:21137621

  4. a Segment-Based Approach for DTM Derivation of Airborne LIDAR Data

    NASA Astrophysics Data System (ADS)

    Tang, Dejin; Zhou, Xiaoming; Jiang, Jie; Li, Caiping

    2016-06-01

    With the characteristics of LIDAR system, raw point clouds represent both terrain and non-terrain surface. In order to generate DTM, the paper introduces one improved filtering method based on the segment-based algorithms. The method generates segments by clustering points based on surface fitting and uses topological and geometric properties for classification. In the process, three major steps are involved. First, the whole datasets is split into several small overlapping tiles. For each tile, by removing wall and vegetation points, accurate segments are found. The segments from all tiles are assigned unique segment number. In the following step, topological descriptions for the segment distribution pattern and height jump between adjacent segments are identified in each tile. Based on the topology and geometry, segment-based filtering algorithm is performed for classification in each tile. Then, based on the spatial location of the segment in one tile, two confidence levels are assigned to the classified segments. The segments with low confidence level are because of losing geometric or topological information in one tile. Thus, a combination algorithm is generated to detect corresponding parts of incomplete segment from multiple tiles. Then another classification algorithm is performed for these segments. The result of these segments will have high confidence level. After that, all the segments in one tile have high confidence level of classification result. The final DTM will add all the terrain segments and avoid duplicate points. At the last of the paper, the experiment show the filtering result and be compared with the other classical filtering methods, the analysis proves the method has advantage in the precision of DTM. But because of the complicated algorithms, the processing speed is little slower, that is the future improvement which should been researched.

  5. A Kinematic Analysis of the Jumping Front-Leg Axe-Kick in Taekwondo

    PubMed Central

    Preuschl, Emanuel; Hassmann, Michaela; Baca, Arnold

    2016-01-01

    The jumping front-leg axe-kick is a valid attacking and counterattacking technique in Taekwondo competition (Streif, 1993). Yet, the existing literature on this technique is sparse (Kloiber et al., 2009). Therefore, the goal of this study was to determine parameters contributing significantly to maximum linear speed of the foot at impact. Parameters are timing of segment and joint angular velocity characteristics and segment lengths of the kicking leg. Moreover, we were interested in the prevalence of proximal-to-distal-sequencing. Three-dimensional kinematics of the kicks of 22 male Taekwondo-athletes (age: 23.3 ± 5.3 years) were recorded via a motion capturing system (Vicon Motion Systems Limited, Oxford, UK). The participants performed maximum effort kicks onto a rack-held kicking pad. Only the kick with the highest impact velocity was analysed, as it was assumed to represent the individual’s best performance. Significant Pearson correlations to impact velocity were found for pelvis tilt angular displacement (r = 0.468, p < 0.05) and for hip extension angular velocity (r = -0.446, p < 0.05) and for the timing of the minima of pelvis tilt velocity (r = -0.426, p < 0.05) and knee flexion velocity (r = -0.480, p < 0.05). Backward step linear regression analysis suggests a model consisting of three predictor variables: pelvis tilt angular displacement, hip flexion velocity at target contact and timing of pelvic tilt angular velocity minimum (adjusted R2 = 0.524). Results of Chi-Squared tests show that neither for the leg-raising period (χ2 = 2.909) of the technique, nor for the leg-lowering period a pattern of proximal-to-distal sequencing is prevalent (χ2 = 0.727). From the results we conclude that the jumping front-leg axe-kick does not follow a proximal-to-distal pattern. Raising the leg early in the technique and apprehending the upper body to be leant back during the leg-lowering period seems to be beneficial for high impact velocity. Furthermore, striking

  6. A Kinematic Analysis of the Jumping Front-Leg Axe-Kick in Taekwondo.

    PubMed

    Preuschl, Emanuel; Hassmann, Michaela; Baca, Arnold

    2016-03-01

    The jumping front-leg axe-kick is a valid attacking and counterattacking technique in Taekwondo competition (Streif, 1993). Yet, the existing literature on this technique is sparse (Kloiber et al., 2009). Therefore, the goal of this study was to determine parameters contributing significantly to maximum linear speed of the foot at impact. Parameters are timing of segment and joint angular velocity characteristics and segment lengths of the kicking leg. Moreover, we were interested in the prevalence of proximal-to-distal-sequencing. Three-dimensional kinematics of the kicks of 22 male Taekwondo-athletes (age: 23.3 ± 5.3 years) were recorded via a motion capturing system (Vicon Motion Systems Limited, Oxford, UK). The participants performed maximum effort kicks onto a rack-held kicking pad. Only the kick with the highest impact velocity was analysed, as it was assumed to represent the individual's best performance. Significant Pearson correlations to impact velocity were found for pelvis tilt angular displacement (r = 0.468, p < 0.05) and for hip extension angular velocity (r = -0.446, p < 0.05) and for the timing of the minima of pelvis tilt velocity (r = -0.426, p < 0.05) and knee flexion velocity (r = -0.480, p < 0.05). Backward step linear regression analysis suggests a model consisting of three predictor variables: pelvis tilt angular displacement, hip flexion velocity at target contact and timing of pelvic tilt angular velocity minimum (adjusted R(2) = 0.524). Results of Chi-Squared tests show that neither for the leg-raising period (χ(2) = 2.909) of the technique, nor for the leg-lowering period a pattern of proximal-to-distal sequencing is prevalent (χ(2) = 0.727). From the results we conclude that the jumping front-leg axe-kick does not follow a proximal-to-distal pattern. Raising the leg early in the technique and apprehending the upper body to be leant back during the leg-lowering period seems to be beneficial for high impact velocity. Furthermore

  7. Evaluation of Wheat Chromosome Translocation Lines for High Temperature Stress Tolerance at Grain Filling Stage

    PubMed Central

    Pradhan, Gautam Prasad; Prasad, P. V. Vara

    2015-01-01

    High temperature (HT, heat) stress is detrimental to wheat (Triticum aestivum L.) production. Wild relatives of bread wheat may offer sources of HT stress tolerance genes because they grow in stressed habitats. Wheat chromosome translocation lines, produced by introgressing small segments of chromosome from wild relatives to bread wheat, were evaluated for tolerance to HT stress during the grain filling stage. Sixteen translocation lines and four wheat cultivars were grown at optimum temperature (OT) of 22/14°C (day/night). Ten days after anthesis, half of the plants were exposed to HT stress of 34/26°C for 16 d, and other half remained at OT. Results showed that HT stress decreased grain yield by 43% compared with OT. Decrease in individual grain weight (by 44%) was the main reason for yield decline at HT. High temperature stress had adverse effects on leaf chlorophyll content and Fv/Fm; and a significant decrease in Fv/Fm was associated with a decline in individual grain weight. Based on the heat response (heat susceptibility indices, HSIs) of physiological and yield traits to each other and to yield HSI, TA5594, TA5617, and TA5088 were highly tolerant and TA5637 and TA5640 were highly susceptible to HT stress. Our results suggest that change in Fv/Fm is a highly useful trait in screening genotypes for HT stress tolerance. This study showed that there is genetic variability among wheat chromosome translocation lines for HT stress tolerance at the grain filling stage and we suggest further screening of a larger set of translocation lines. PMID:25719199

  8. Genomic Heterogeneity of Translocation Renal Cell Carcinoma

    PubMed Central

    Couturier, Jérôme; Molinié, Vincent; Escudier, Bernard; Camparo, Philippe; Su, Xiaoping; Yao, Hui; Tamboli, Pheroze; Lopez-Terrada, Dolores; Picken, Maria; Garcia, Marileila; Multani, Asha S.; Pathak, Sen; Wood, Christopher G.; Tannir, Nizar M.

    2013-01-01

    Purpose Translocation renal cell carcinoma (tRCC) is a rare subtype of kidney cancer involving the TFEB/TFE3 genes. We aimed to investigate the genomic and epigenetic features of this entity. Experimental design Cytogenomic analysis was performed with 250K single-nucleotide polymorphism microarrays on 16 tumor specimens and 4 cell lines. LINE-1 methylation, a surrogate marker of DNA methylation, was performed on 27 cases using pyrosequencing. Results tRCC showed cytogenomic heterogeneity, with 31.2% and 18.7% of cases presenting similarities with clear-cell and papillary RCC profiles, respectively. The most common alteration was a 17q gain in 7 tumors (44%), followed by a 9p loss in 6 cases (37%). Less frequent were losses of 3p and 17p in 5 cases (31%) each. Patients with 17q gain were older (P = 0.0006), displayed more genetic alterations (P < 0.003) and had a worse outcome (P = 0.002) than patients without it. Analysis comparing gene-expression profiling of a subset of tumors bearing 17q gain and those without suggest large scale dosage effects and TP53 haploinsufficiency without any somatic TP53 mutation identified. Cell-line based cytogenetic studies revealed that 17q gain can be related to isochromosome 17 and/or to multiple translocations occurring around 17q breakpoints. Finally, LINE-1 methylation was lower in tRCC tumors from adults compared to tumors from young patients (71.1% vs. 76.7%, P = 0.02). Conclusions Our results reveal genomic heterogeneity of tRCC with similarities to other renal tumor subtypes and raise important questions about the role of TFEB/TFE3 translocations and other chromosomal imbalances in tRCC biology. PMID:23817689

  9. ASCAN Helms simulates parachute jump during VAFB training exercises

    NASA Technical Reports Server (NTRS)

    1990-01-01

    1990 Group 13 Astronaut Candidate (ASCAN) Susan J. Helms simulates a parachute jump during ground egress and parasail training exercises at Vance Air Force Base (VAFB), Enid, Oklahoma. With her arms folded against her chest, Helms jumps from a brick platform onto the ground. In line behind her are Charles J. Precourt followed by Leroy Chiao. The training is designed to prepare the ASCANs for proper survival measures to take in the event of an emergency aboard the T-38 jet trainer aircraft they will frequently use once they become full-fledged astronauts. ASCANs completed the VAFB training courses from 07-29-90 through 07-31-90.

  10. Detection of atomic clock frequency jumps with the Kalman filter.

    PubMed

    Galleani, Lorenzo; Tavella, Patrizia

    2012-03-01

    Frequency jumps are common anomalies in atomic clocks aboard navigation system satellites. These anomalous behaviors must be detected quickly and accurately to minimize the impact on user positioning. We develop a detector for frequency jumps based on the Kalman filter. Numerical simulations show that the detector is fast, with high probability of detection and low probability of false alarms. It also has a low computational cost because it takes advantage of the recursive nature of the Kalman filter. Therefore, it can be used in applications in which little computational power is available, such as aboard navigation system satellites. PMID:22481785

  11. Incorporating compliant elastomers for jumping locomotion in microrobots

    NASA Astrophysics Data System (ADS)

    Gerratt, Aaron P.; Bergbreiter, Sarah

    2013-01-01

    Small insects and other animals use a multitude of materials to realize specific functions, including locomotion. This paper demonstrates application of the first microfabrication process to incorporate high aspect ratio compliant elastomer structures in-plane with traditional silicon microelectromechanical systems (MEMS). By incorporating these new materials, compact energy storage systems based on elastomer springs for small jumping robots have been demonstrated. Results include a 4 mm×4 mm jumping mechanism that has reached heights of 32 cm, × 80 its own height, and an on-chip actuated mechanism that has been used to propel a 1.4 mg projectile over 7 cm.

  12. Jumping mechanisms in gum treehopper insects (Hemiptera, Eurymelinae).

    PubMed

    Burrows, Malcolm

    2013-07-15

    Jumping in a species of Australian gum treehopper was analysed from high-speed images. Pauroeurymela amplicincta adults and nymphs lived together in groups that were tended by ants, but only adults jumped. The winged adults with a body mass of 23 mg and a body length of 7 mm had some morphological characteristics intermediate between those of their close relatives the leafhoppers (Cicadellidae) and the treehoppers (Membracidae). They, like leafhoppers, lacked the prominent prothoracic helmets of membracid treehoppers, and their large hind coxae were linked by press studs (poppers), that are present in leafhoppers but not treehoppers. The hindlegs were only 30-40% longer than the other legs and 67% of body length. They are thus of similar proportion to the hindlegs of treehoppers but much shorter than those of most leafhoppers. Jumping was propelled by the hindlegs, which moved in the same plane as each other beneath and almost parallel to the longitudinal axis of the body. A jump was preceded by full levation of the coxo-trochanteral joints of the hindlegs. In its best jumps, the rapid depression of these joints then accelerated the insect in 1.4 ms to a take-off velocity of 3.8 m s(-1) so that it experienced a force of almost 280 g. In 22% of jumps, the wings opened before take-off but did not flap until the gum treehopper was airborne, when the body rotated little in any plane. The energy expended was 170 μJ, the power output was 122 mW and the force exerted was 64 mN. Such jumps are predicted to propel the insect forwards 1450 mm (200 times body length) and to a height of 430 mm if there is no effect of wind resistance. The power output per mass of jumping muscle far exceeded the maximum active contractile limit of muscle and indicates that a catapult-like action must be used. This eurymelid therefore out-performs both leafhoppers and treehoppers in i ts faster acceleration and in its higher take-off velocity. PMID:23619401

  13. Hydraulic jumps in inhomogeneous strongly coupled toroidal dust flows

    NASA Astrophysics Data System (ADS)

    Piel, Alexander; Wilms, Jochen

    2016-07-01

    The inhomogeneous flow of strongly coupled dust particles in a toroidal particle trap with harmonic radial confinement is analyzed in the incompressible fluid limit. It is shown that the flow can spontaneously generate shock-like events, which are similar to the hydraulic jump in open channel flows. A definition of the Froude number for this model is given and the critical speed is recovered as the group velocity of surface waves. This hydraulic model is compared with molecular-dynamics simulations, which show that a sudden bifurcation of the flow lines and a localized temperature peak appear just at the point where the critical condition for the hydraulic jump is located.

  14. Microbial Translocation Across the GI Tract*

    PubMed Central

    Brenchley, Jason M.; Douek, Daniel C.

    2012-01-01

    The lumen of the gastrointestinal (GI) tract is home to an enormous quantity of different bacterial species, our microbiota, that thrive in an often symbiotic relationship with the host. Given that the healthy host must regulate contact between the microbiota and its immune system to avoid overwhelming systemic immune activation, humans have evolved several mechanisms to attenuate systemic microbial translocation (MT) and its consequences. However, several diseases are associated with the failure of one or more of these mechanisms, with consequent immune activation and deleterious effects on health. Here, we discuss the mechanisms underlying MT, diseases associated with MT, and therapeutic interventions that aim to decrease it. PMID:22224779

  15. Palaeoseismology on Jumping Faults: the Case of the Kamena Vourla Fault, Central Greece.

    NASA Astrophysics Data System (ADS)

    Dewez, T. J.; Stewart, I. S.

    2001-12-01

    The basinward migration of normal faults is a widely documented phenomenon around the world, but just how and how fast this happens is still unclear. In Greece, active normal fault systems are often located along the sea and their most active segment lies underwater (eg 1981 Gulf of Corinth earthquakes). Palaeoseismologists are confronted with a difficult problem where the fault segment that they can trench on land is not necessarily the one that reflects the most recent fault activity. The Kamena Vourla fault offers the opportunity to study this phenomenon of `fault jumping' along the southern shore of the Gulf of Evvia in central Greece. Despite a dramatic tectonic expression on land, no historical or palaeoseismic earthquake can be positively ascribed to it. At its eastern tip, the Agios Konstantinos-Livanates segment exhibits a remarkably fresh assemblage of tectonic landforms. Uplifted sedimentary basins in its footwall, tilted wave-cut platforms, and dislocated stratigraphic marker horizons are among the clearest evidence of late Quaternary activity. Remarkable exposures of the main limestone fault plane also preserve signs of Holocene reactivation. However the occurrence of uplifted coastal sediments in its immediate hangingwall contests the idea that the onshore Agios Konstantinos-Livanates segment is the main active fault trace. Furthermore, identical Holocene marine fauna are presently exposed one meter above sea level identically on both sides of the fault. The tectonic geomorphology of the area strongly implies that an offshore segment, the Arkitsa segment, has gradually taken over some of its the activity during the late Pleistocene and the Holocene. To unravel the switching of activity between those two segments, we present a quantitative analysis combining a high-resolution photogrammetric Digital Elevation Model (DEM), field data with elastic half-space modeling. From the DEM, tilted former wave-cut platforms are automatically identified and their

  16. Geographic Translocation of Bats: Known and Potential Problems

    PubMed Central

    2003-01-01

    Natural, accidental, and intentional translocation of bats, both intra- and intercontinentally, has been documented. Some bats have been translocated while incubating infectious diseases, including rabies or related lyssavirus infections; others have escaped confinement en route to or at their destinations, while others have been released deliberately. Known events and potential consequences of bat translocation are reviewed, including a proposed solution to the attendant problems. PMID:12533276

  17. Measurement of three-dimensional posture and trajectory of lower body during standing long jumping utilizing body-mounted sensors.

    PubMed

    Ibata, Yuki; Kitamura, Seiji; Motoi, Kosuke; Sagawa, Koichi

    2013-01-01

    The measurement method of three-dimensional posture and flying trajectory of lower body during jumping motion using body-mounted wireless inertial measurement units (WIMU) is introduced. The WIMU is composed of three-dimensional (3D) accelerometer and gyroscope of two kinds with different dynamic range and one 3D geomagnetic sensor to adapt to quick movement. Three WIMUs are mounted under the chest, right thigh and right shank. Thin film pressure sensors are connected to the shank WIMU and are installed under right heel and tiptoe to distinguish the state of the body motion between grounding and jumping. Initial and final postures of trunk, thigh and shank at standing-still are obtained using gravitational acceleration and geomagnetism. The posture of body is determined using the 3D direction of each segment updated by the numerical integration of angular velocity. Flying motion is detected from pressure sensors and 3D flying trajectory is derived by the double integration of trunk acceleration applying the 3D velocity of trunk at takeoff. Standing long jump experiments are performed and experimental results show that the joint angle and flying trajectory agree with the actual motion measured by the optical motion capture system. PMID:24110831

  18. Intra- and inter-subject variation in lower limb coordination during countermovement jumps in children and adults.

    PubMed

    Raffalt, Peter C; Alkjær, Tine; Simonsen, Erik B

    2016-04-01

    The purpose of the present study was to investigate the coordination pattern and coordination variability (intra-subject and inter-subject) in children and adults during vertical countermovement jumps. Ten children (mean age: 11.5±1.8years) and ten adults (mean age: 26.1±4.9years) participated in the experiment. Lower body 3D-kinematics and kinetics from both legs were obtained during 9 vertical jumps of each subject. Coordination pattern and coordination variability of intra-limb and inter-limb coupling were established by modified vector coding and continuous relative phase. The adult group jumped higher and with less performance variability compared to the children. Group differences were mainly observed in the right-left foot coupling. The intra-subject coordination variability was higher in coupling of proximal segments in children compared to adults. No group differences were observed in inter-subject variability. Based on these results, it was concluded that the same movement solutions were available to both age groups, but the children were less able to consistently utilize the individually chosen coordination pattern. Thus, this ability appears to be developed through normal ontogenesis. PMID:26724430

  19. Differences between the elite and subelite sprinters in kinematic and dynamic determinations of countermovement jump and drop jump.

    PubMed

    Coh, Milan; Mackala, Krzysztof

    2013-11-01

    The aim of this study was to examine the relationship between selected variables of lower extremities explosive power measured via countermovement jump (CMJ) and drop jump (DJ) and sprinting ability over 60- and 100-m dash. Twelve national-level Slovenian sprinters were assigned to 2 groups: elite (n = 6) and subelite (n = 6). The grouping criterion was performance in 60 and 100 m in official competition. Biomechanical parameters of both jumps were measured with the use of bipedal force platform and a system of 9 infraspectral charge-coupled device (CCD) cameras with a 200 Hz frequency. Differences between the groups of sprinters were examined with the use of repeated-measures analysis of variance. In CMJ, the differences (p < 0.05) between the groups were revealed in take off velocity (elites = 3.23 m · s, subelites = 2.94 m·s), height of the jump, vertical velocity of body center of gravity, and the impulse of force in the concentric phase of the jump (concentric impulse: elites = 123.91 N · s; subelites = 108.06 N · s). In the DJ, elite and subelite sprinters differentiated in the realization of movement velocity in the eccentric and concentric phases (take off velocity: elites = 3.18 m · s, subelites = 2.87 m · s; eccentric velocity: elites = 3.05 m · s, subelites = 2.81 m · s). This investigation provides evidence that vertical jumps and DJs are very important tools to meet the demands of sprint training according eccentric-concentric muscular work. The DJ showed better quality than CMJ in the neuromuscular specificity. PMID:23442283

  20. The Type III Secretion Translocation Pore Senses Host Cell Contact

    PubMed Central

    Armentrout, Erin I.; Rietsch, Arne

    2016-01-01

    Type III secretion systems (T3SS) are nano-syringes used by a wide range of Gram-negative pathogens to promote infection by directly injecting effector proteins into targeted host cells. Translocation of effectors is triggered by host-cell contact and requires assembly of a pore in the host-cell plasma membrane, which consists of two translocator proteins. Our understanding of the translocation pore, how it is assembled in the host cell membrane and its precise role in effector translocation, is extremely limited. Here we use a genetic technique to identify protein-protein contacts between pore-forming translocator proteins, as well as the T3SS needle-tip, that are critical for translocon function. The data help establish the orientation of the translocator proteins in the host cell membrane. Analysis of translocon function in mutants that break these contacts demonstrates that an interaction between the pore-forming translocator PopD and the needle-tip is required for sensing host cell contact. Moreover, tethering PopD at a dimer interface also specifically prevents host-cell sensing, arguing that the translocation pore is actively involved in detecting host cell contact. The work presented here therefore establishes a signal transduction pathway for sensing host cell contact that is initiated by a conformational change in the translocation pore, and is subsequently transmitted to the base of the apparatus via a specific contact between the pore and the T3SS needle-tip. PMID:27022930

  1. The protein translocation machinery of the endoplasmic reticulum.

    PubMed

    Walter, P; Gilmore, R; Müller, M; Blobel, G

    1982-12-24

    The rough endoplasmic reticulum (r.e.r.) has been postulated to possess a single translation-coupled translocation system (in multiple copies) that effects signal sequence-mediated translocation of all secretory and lysosomal proteins and integration of all integral membrane proteins whose port of entry is the rough endoplasmic reticulum (G. Blobel 1980 Proc. natn. Acad. Sci. U.S.A. 77, 1496-1500). Two proteins have been isolated that are components of the r.e.r. translocation system. Their properties and function in protein translocation across and integration into membranes are discussed. PMID:6131460

  2. Rediscovering market segmentation.

    PubMed

    Yankelovich, Daniel; Meer, David

    2006-02-01

    In 1964, Daniel Yankelovich introduced in the pages of HBR the concept of nondemographic segmentation, by which he meant the classification of consumers according to criteria other than age, residence, income, and such. The predictive power of marketing studies based on demographics was no longer strong enough to serve as a basis for marketing strategy, he argued. Buying patterns had become far better guides to consumers' future purchases. In addition, properly constructed nondemographic segmentations could help companies determine which products to develop, which distribution channels to sell them in, how much to charge for them, and how to advertise them. But more than 40 years later, nondemographic segmentation has become just as unenlightening as demographic segmentation had been. Today, the technique is used almost exclusively to fulfill the needs of advertising, which it serves mainly by populating commercials with characters that viewers can identify with. It is true that psychographic types like "High-Tech Harry" and "Joe Six-Pack" may capture some truth about real people's lifestyles, attitudes, self-image, and aspirations. But they are no better than demographics at predicting purchase behavior. Thus they give corporate decision makers very little idea of how to keep customers or capture new ones. Now, Daniel Yankelovich returns to these pages, with consultant David Meer, to argue the case for a broad view of nondemographic segmentation. They describe the elements of a smart segmentation strategy, explaining how segmentations meant to strengthen brand identity differ from those capable of telling a company which markets it should enter and what goods to make. And they introduce their "gravity of decision spectrum", a tool that focuses on the form of consumer behavior that should be of the greatest interest to marketers--the importance that consumers place on a product or product category. PMID:16485810

  3. Fault rupture segmentation

    NASA Astrophysics Data System (ADS)

    Cleveland, Kenneth Michael

    A critical foundation to earthquake study and hazard assessment is the understanding of controls on fault rupture, including segmentation. Key challenges to understanding fault rupture segmentation include, but are not limited to: What determines if a fault segment will rupture in a single great event or multiple moderate events? How is slip along a fault partitioned between seismic and seismic components? How does the seismicity of a fault segment evolve over time? How representative are past events for assessing future seismic hazards? In order to address the difficult questions regarding fault rupture segmentation, new methods must be developed that utilize the information available. Much of the research presented in this study focuses on the development of new methods for attacking the challenges of understanding fault rupture segmentation. Not only do these methods exploit a broader band of information within the waveform than has traditionally been used, but they also lend themselves to the inclusion of even more seismic phases providing deeper understandings. Additionally, these methods are designed to be fast and efficient with large datasets, allowing them to utilize the enormous volume of data available. Key findings from this body of work include demonstration that focus on fundamental earthquake properties on regional scales can provide general understanding of fault rupture segmentation. We present a more modern, waveform-based method that locates events using cross-correlation of the Rayleigh waves. Additionally, cross-correlation values can also be used to calculate precise earthquake magnitudes. Finally, insight regarding earthquake rupture directivity can be easily and quickly exploited using cross-correlation of surface waves.

  4. Acute Improvement of Vertical Jump Performance After Isometric Squats Depends on Knee Angle and Vertical Jumping Ability.

    PubMed

    Tsoukos, Athanasios; Bogdanis, Gregory C; Terzis, Gerasimos; Veligekas, Panagiotis

    2016-08-01

    Tsoukos, A, Bogdanis, GC, Terzis, G, and Veligekas, P. Acute improvement of vertical jump performance after isometric squats depends on knee angle and vertical jumping ability. J Strength Cond Res 30(8): 2250-2257, 2016-This study examined the acute effects of maximum isometric squats at 2 different knee angles (90 or 140°) on countermovement jump (CMJ) performance in power athletes. Fourteen national-level male track and field power athletes completed 3 main trials (2 experimental and 1 control) in a randomized and counterbalanced order 1 week apart. Countermovement jump performance was evaluated using a force-plate before and 15 seconds, 3, 6, 9, and 12 minutes after 3 sets of 3 seconds maximum isometric contractions with 1-minute rest in between, from a squat position with knee angle set at 90 or 140°. Countermovement jump performance was improved compared with baseline only in the 140° condition by 3.8 ± 1.2% on the 12th minute of recovery (p = 0.027), whereas there was no change in CMJ height in the 90° condition. In the control condition, there was a decrease in CMJ performance over time, reaching -3.6 ± 1.2% (p = 0.049) after 12 minutes of recovery. To determine the possible effects of baseline jump performance on subsequent CMJ performance, subjects were divided into 2 groups ("high jumpers" and "low jumpers"). The baseline CMJ values of "high jumpers" and "low jumpers" differed significantly (CMJ: 45.1 ± 2.2 vs. 37.1 ± 3.9 cm, respectively, p = 0.001). Countermovement jump was increased only in the "high jumpers" group by 5.4 ± 1.4% (p = 0.001) and 7.4 ± 1.2% (p = 0.001) at the knee angles of 90 and 140°, respectively. This improvement was larger at the 140° angle (p = 0.049). Knee angle during isometric squats and vertical jumping ability are important determinants of the acute CMJ performance increase observed after a conditioning activity. PMID:26808841

  5. Multistep protein unfolding during nanopore translocation

    NASA Astrophysics Data System (ADS)

    Rodriguez-Larrea, David; Bayley, Hagan

    2013-04-01

    Cells are divided into compartments and separated from the environment by lipid bilayer membranes. Essential molecules are transported back and forth across the membranes. We have investigated how folded proteins use narrow transmembrane pores to move between compartments. During this process, the proteins must unfold. To examine co-translocational unfolding of individual molecules, we tagged protein substrates with oligonucleotides to enable potential-driven unidirectional movement through a model protein nanopore, a process that differs fundamentally from extension during force spectroscopy measurements. Our findings support a four-step translocation mechanism for model thioredoxin substrates. First, the DNA tag is captured by the pore. Second, the oligonucleotide is pulled through the pore, causing local unfolding of the C terminus of the thioredoxin adjacent to the pore entrance. Third, the remainder of the protein unfolds spontaneously. Finally, the unfolded polypeptide diffuses through the pore into the recipient compartment. The unfolding pathway elucidated here differs from those revealed by denaturation experiments in solution, for which two-state mechanisms have been proposed.

  6. Fertility of male and female mice heterozygous for the reciprocal translocation T(7;17)3BKM.

    PubMed

    Koleva, M; Benova, D

    1992-01-01

    The present paper describes the fertility of male and female mice heterozygous for the reciprocal translocation T(7;17)3BKM. This translocation was induced by gamma rays in the spermatozoa of an irradiated parent. It is characterized by "asymmetrical" localization of the breakpoints, distally in Chromosome 7 (7F5) and proximally in Chromosome 17 (17B1). The data presented here relate only those matings in which, for both partners, heterozygosity or normality could be confirmed cytogenetically. The results indicate that both male and female translocation heterozygotes are fertile, their mean litter size being reduced to about 50% of that of normal littermates. This leads to the conclusion that the multivalents mainly undergo either alternate or adjacent-1 2:2 segregation. No viable tertiary trisomics were observed among the progeny of the translocation carriers. Analysis of the frequency of the different types of multivalents in diakinesis-metaphase I spermatocytes showed a significant predominance of chain-type figures (CIV and CIII+I), with chains of four elements (CIV) being more frequent than other configurations. This demonstrates that the small marker chromosome remains attached by one of its segments to the tetravalent. PMID:1486808

  7. The chain sucker: translocation dynamics of a polymer chain into a long narrow channel driven by longitudinal flow.

    PubMed

    Luo, Kaifu; Metzler, Ralf

    2011-04-01

    Using analytical techniques and Langevin dynamics simulations, we investigate the dynamics of polymer translocation into a narrow channel of width R embedded in two dimensions, driven by a force proportional to the number of monomers in the channel. Such a setup mimics typical experimental situations in nano/microfluidics. During the translocation process if the monomers in the channel can sufficiently quickly assume steady state motion, we observe the scaling τ ∼ N∕F of the translocation time τ with the driving force F per bead and the number N of monomers per chain. With smaller channel width R, steady state motion cannot be achieved, effecting a nonuniversal dependence of τ on N and F. From the simulations we also deduce the waiting time distributions under various conditions for the single segment passage through the channel entrance. For different chain lengths but the same driving force, the curves of the waiting time as a function of the translocation coordinate s feature a maximum located at identical s(max), while with increasing the driving force or the channel width the value of s(max) decreases. PMID:21476775

  8. Mitochondrial translocation contact sites: separation of dynamic and stabilizing elements in formation of a TOM-TIM-preprotein supercomplex.

    PubMed

    Chacinska, Agnieszka; Rehling, Peter; Guiard, Bernard; Frazier, Ann E; Schulze-Specking, Agnes; Pfanner, Nikolaus; Voos, Wolfgang; Meisinger, Chris

    2003-10-15

    Preproteins with N-terminal presequences are imported into mitochondria at translocation contact sites that include the translocase of the outer membrane (TOM complex) and the presequence translocase of the inner membrane (TIM23 complex). Little is known about the functional cooperation of these translocases. We have characterized translocation contact sites by a productive TOM-TIM-preprotein supercomplex to address the role of three translocase subunits that expose domains to the intermembrane space (IMS). The IMS domain of the receptor Tom22 is required for stabilization of the translocation contact site supercomplex. Surprisingly, the N-terminal segment of the channel Tim23, which tethers the TIM23 complex to the outer membrane, is dispensable for both protein import and generation of the TOM-TIM supercomplex. Tim50, with its large IMS domain, is crucial for generation but not for stabilization of the supercomplex. Thus, Tim50 functions as a dynamic factor and the IMS domain of Tom22 represents a stabilizing element in formation of a productive translocation contact site supercomplex. PMID:14532110

  9. Observations of ''granular jump'' in the pneumatic conveying system

    SciTech Connect

    Jaworski, Artur J.; Dyakowski, Tomasz

    2007-08-15

    This paper presents a preliminary study of a previously unreported phenomenon of the ''gas driven granular jump'', observed in the gas-solids flow within the pneumatic conveying system. From the phenomenological point of view, it resembles the already known processes such as hydraulic jumps in shallow water or granular jumps in granular flows in chutes or avalanches (although it seems most appropriate to explain it by analogy to a propagating granular bore). Clearly, unlike in classical phenomena of this type, the flow itself is driven by the aerodynamic forces related to the gas flow and the behaviour of the front of the ''jump'' is modified significantly by their presence. A series of high-speed camera visualisations are presented, which focus on this unusual behaviour of the flow on the border-line between cluster and stratified flow regimes in a horizontal pipe. Some similarities are drawn between the observed phenomenon and the broader class of problems exhibiting transition between super- and sub-critical flows. The fluid dynamical aspects and possible mechanisms behind the new phenomenon are discussed and the results obtained are compared quantitatively with simple theoretical models. (author)

  10. Environmentally transmitted parasites: Host-jumping in a heterogeneous environment.

    PubMed

    Caraco, Thomas; Cizauskas, Carrie A; Wang, Ing-Nang

    2016-05-21

    Groups of chronically infected reservoir-hosts contaminate resource patches by shedding a parasite׳s free-living stage. Novel-host groups visit the same patches, where they are exposed to infection. We treat arrival at patches, levels of parasite deposition, and infection of the novel host as stochastic processes, and derive the expected time elapsing until a host-jump (initial infection of a novel host) occurs. At stationarity, mean parasite densities are independent of reservoir-host group size. But within-patch parasite-density variances increase with reservoir group size. The probability of infecting a novel host declines with parasite-density variance; consequently larger reservoir groups extend the mean waiting time for host-jumping. Larger novel-host groups increase the probability of a host-jump during any single patch visit, but also reduce the total number of visits per unit time. Interaction of these effects implies that the waiting time for the first infection increases with the novel-host group size. If the reservoir-host uses resource patches in any non-uniform manner, reduced spatial overlap between host species increases the waiting time for host-jumping. PMID:26921466

  11. Jump at the Sun: Perspectives of Black Women Administrators.

    ERIC Educational Resources Information Center

    Northern Virginia Community Coll., Annandale.

    Four community college administrators, including a president, provost, director of learning resources, and dean of student services, offer their perspectives on what it means to be a black woman administrator in higher education today. First, "Jump at the Sun," by Bernadine Coleman Thomas, contends that a black woman administrator can be…

  12. "Early College" High School Jump-Starts Higher Learning

    ERIC Educational Resources Information Center

    Chmelynski, Carol

    2004-01-01

    Early college high schools allow students to earn both a high school diploma and two years of college credit simultaneously. The concept makes college more affordable, provides more support to students in their first two years of college, and gives students a jump start on their careers by eliminating time-wasting activities in the last two years…

  13. Stabilizing entanglement by quantum-jump-based feedback

    SciTech Connect

    Carvalho, A. R. R.; Hope, J. J.

    2007-07-15

    We show that direct feedback based on quantum-jump detection can be used to generate entangled steady states. We present a strategy that is insensitive to detection inefficiencies and robust against errors in the control Hamiltonian. This feedback procedure is also shown to overcome spontaneous emission effects by stabilizing states with a high degree of entanglement.

  14. Considering Jumping Ship? A Pirate Looks at Retirement

    ERIC Educational Resources Information Center

    Kilpatrick, Bob G.

    2011-01-01

    If you're like me, a "senior" faculty member at a public state university facing significant budget cuts, recently you've probably thought about leaving your current position for another faculty position in a different state. A possible reason for considering jumping ship is envisioning a clearer picture of your retirement as it nears on…

  15. Jump Back in Time: A Living History Resource

    ERIC Educational Resources Information Center

    Peterson, Carol

    2004-01-01

    Gather students and jump back in time to experience what life was like "back then." Through this book, during each day of immersion, students rotate through 14-18 stations of math and vocabulary activities, games, crafts, costumes, and food. Explore legends, songs, maps, and historical events along the way to understand specific times and places…

  16. Delayed Frost Growth on Jumping-Drop Superhydrophobic Surfaces

    SciTech Connect

    Boreyko, Jonathan B; Collier, Pat

    2013-01-01

    Self-propelled jumping drops are continuously removed from a condensing superhydrophobic surface to enable a micrometric steady-state drop size. Here, we report that subcooled condensate on a chilled superhydrophobic surface are able to repeatedly jump off the surface before heterogeneous ice nucleation occurs. Frost still forms on the superhydrophobic surface due to ice nucleation at neighboring edge defects, which eventually spreads over the entire surface via an inter-drop frost wave. The growth of this inter-drop frost front is shown to be up to three times slower on the superhydrophobic surface compared to a control hydrophobic surface, due to the jumping-drop effect dynamically minimizing the average drop size and surface coverage of the condensate. A simple scaling model is developed to relate the success and speed of inter-drop ice bridging to the drop size distribution. While other reports of condensation frosting on superhydrophobic surfaces have focused exclusively on liquid-solid ice nucleation for isolated drops, these findings reveal that the growth of frost is an inter-drop phenomenon that is strongly coupled to the wettability and drop size distribution of the surface. A jumping-drop superhydrophobic condenser was found to be superior to a conventional dropwise condenser in two respects: preventing heterogeneous ice nucleation by continuously removing subcooled condensate, and delaying frost growth by minimizing the success of interdrop ice bridge formation.

  17. A jump persistent turning walker to model zebrafish locomotion

    PubMed Central

    Mwaffo, Violet; Anderson, Ross P.; Butail, Sachit; Porfiri, Maurizio

    2015-01-01

    Zebrafish are gaining momentum as a laboratory animal species for the investigation of several functional and dysfunctional biological processes. Mathematical models of zebrafish behaviour are expected to considerably aid in the design of hypothesis-driven studies by enabling preliminary in silico tests that can be used to infer possible experimental outcomes without the use of zebrafish. This study is motivated by observations of sudden, drastic changes in zebrafish locomotion in the form of large deviations in turn rate. We demonstrate that such deviations can be captured through a stochastic mean reverting jump diffusion model, a process that is commonly used in financial engineering to describe large changes in the price of an asset. The jump process-based model is validated on trajectory data of adult subjects swimming in a shallow circular tank obtained from an overhead camera. Through statistical comparison of the empirical distribution of the turn rate against theoretical predictions, we demonstrate the feasibility of describing zebrafish as a jump persistent turning walker. The critical role of the jump term is assessed through comparison with a simplified mean reversion diffusion model, which does not allow for describing the heavy-tailed distributions observed in the fish turn rate. PMID:25392396

  18. Attention and blood lactate levels in equestrians performing show jumping.

    PubMed

    Perciavalle, Valentina; Di Corrado, Donatella; Scuto, Claudia; Perciavalle, Vincenzo; Coco, Marinella

    2014-06-01

    In equestrian show jumping, attention is particularly important to ensure maximum accuracy. Due to the anaerobic nature of the jumping and its requirement for precision coordination between human and horse, there may be a relation between the onset of lactic threshold and decrease in attention. In 12 healthy and injury-free equestrians (6 men, 6 women), the effects (blood lactate and glucose) of a show jumping course (250 m long with eight vertical obstacles with a height of 1.15 m height) on capacity and selectivity of attention was assessed. A typical reaction time paradigm and test of divided attention were administered. At the end of the course a significant increase of blood lactate was observed, whereas blood glucose did not significantly change. A deterioration of attention (intensity and selectivity) and a worsening of performance with increasing of blood lactate were observed. The present results led to the conclusion that the increase in blood lactate that occurs in riders executing a show jumping course is associated with worsening of both attentive capabilities and performance. PMID:25068743

  19. The Hydraulic Jump: Finding Complexity in Turbulent Water

    ERIC Educational Resources Information Center

    Vondracek, Mark

    2013-01-01

    Students who do not progress to more advanced science disciplines in college generally do not realize that seemingly simple physical systems are--when studied in detail--more complex than one might imagine. This article presents one such phenomenon--the hydraulic jump--as a way to help students see the complexity behind the seemingly simple, and…

  20. The Landing Phase of a Jump Strategies to Minimize Injuries

    ERIC Educational Resources Information Center

    Bressel, Eadric; Cronin, John

    2005-01-01

    Most people probably do not remember being coached to jump, or--more important--to land. Research on landing concentrates on the impact forces associated with landing, the consequential effect on the legs, and the subsequent injury potential. There is an abundance of literature on how to create stronger and more powerful muscles, which may be…

  1. Jump Patterns: Percussive Dance and the Path to Math

    ERIC Educational Resources Information Center

    Rosenfeld, Malke

    2011-01-01

    In this article, the author describes an innovative collaboration with an elementary school math teacher that leads to original student choreography and engaging mathematical thinking. Using a tool the author created called Jump Patterns, students at Fox Hill Elementary School in Indianapolis, Indiana, engage in a robust, creative, choreographic…

  2. A control theoretic approach to venom immunotherapy with state jumps.

    PubMed

    Chang, H; Astolfi, A; Shim, H

    2010-01-01

    We investigate a model-based control method to boost the immune response. We apply this control method to select the appropriate immune response between the Th1 and Th2 responses. The idea of state jump is discussed using hybrid models notation. To implement the control idea we propose physically available methods. PMID:21095900

  3. Solving the Chapman-Kolmogorov equation for a jumping process

    NASA Astrophysics Data System (ADS)

    Kamińska, A.; Srokowski, T.

    2003-06-01

    A general solution to the Chapman-Kolmogorov equation for a jumping process called the “kangaroo process” is derived. A special case of algebraic dependences is discussed in detail. In particular, simple asymptotic formulas for probability distribution are presented. It is demonstrated that there are two different classes of limiting stationary distributions. An expression for the covariance is also derived.

  4. Bootstrapping structured page segmentation

    NASA Astrophysics Data System (ADS)

    Ma, Huanfeng; Doermann, David S.

    2003-01-01

    In this paper, we present an approach to the bootstrap learning of a page segmentation model. The idea evolves from attempts to segment dictionaries that often have a consistent page structure, and is extended to the segmentation of more general structured documents. In cases of highly regular structure, the layout can be learned from examples of only a few pages. The system is first trained using a small number of samples, and a larger test set is processed based on the training result. After making corrections to a selected subset of the test set, these corrected samples are combined with the original training samples to generate bootstrap samples. The newly created samples are used to retrain the system, refine the learned features and resegment the test samples. This procedure is applied iteratively until the learned parameters are stable. Using this approach, we do not need to initially provide a large set of training samples. We have applied this segmentation to many structured documents such as dictionaries, phone books, spoken language transcripts, and obtained satisfying segmentation performance.

  5. Scorpion image segmentation system

    NASA Astrophysics Data System (ADS)

    Joseph, E.; Aibinu, A. M.; Sadiq, B. A.; Bello Salau, H.; Salami, M. J. E.

    2013-12-01

    Death as a result of scorpion sting has been a major public health problem in developing countries. Despite the high rate of death as a result of scorpion sting, little report exists in literature of intelligent device and system for automatic detection of scorpion. This paper proposed a digital image processing approach based on the floresencing characteristics of Scorpion under Ultra-violet (UV) light for automatic detection and identification of scorpion. The acquired UV-based images undergo pre-processing to equalize uneven illumination and colour space channel separation. The extracted channels are then segmented into two non-overlapping classes. It has been observed that simple thresholding of the green channel of the acquired RGB UV-based image is sufficient for segmenting Scorpion from other background components in the acquired image. Two approaches to image segmentation have also been proposed in this work, namely, the simple average segmentation technique and K-means image segmentation. The proposed algorithm has been tested on over 40 UV scorpion images obtained from different part of the world and results obtained show an average accuracy of 97.7% in correctly classifying the pixel into two non-overlapping clusters. The proposed 1system will eliminate the problem associated with some of the existing manual approaches presently in use for scorpion detection.

  6. Cooperative processes in image segmentation

    NASA Technical Reports Server (NTRS)

    Davis, L. S.

    1982-01-01

    Research into the role of cooperative, or relaxation, processes in image segmentation is surveyed. Cooperative processes can be employed at several levels of the segmentation process as a preprocessing enhancement step, during supervised or unsupervised pixel classification and, finally, for the interpretation of image segments based on segment properties and relations.

  7. AGS tune jump system to cross horizontal depolarization resonances overview

    SciTech Connect

    Glenn, J.W.; Ahrens, L.; Fu, W.; Mi, J.L.; Rosas, P.; Schoefer, V.; Theisen, C.; Altinbas, Z.

    2011-03-28

    Two partial snakes overcome the vertical depolarizing resonances in the AGS. But a new type of depolarizing intrinsic resonance from horizontal motion appeared. We reduce these using horizontal tune jumps timed to these resonances. We gain a factor of six in crossing rate with a tune jump of 0.05 in 100 {micro}s. Two quadrapoles, we described in 2009, pulse 42 times, the current matching beam energy. The power supplies for these quads are described in detail elsewhere in this conference. The controls for the Jump Quad system is based on a BNL designed Quad Function Generator. Two modules are used; one for timing, and one to supply reference voltages. Synchronization is provided by a proprietary serial bus, the Event Link. The AgsTuneJump application predicts the times of the resonances during the AGS cycle and calculates the power supply trigger times from externally collected tune and energy versus time data and the Low and High PS voltage functions from a voltage to current model of the power supply. The system was commissioned during runs 09 & 10 and is operational. Many beam effects are described elsewhere. The TuneJump system has worked well and has caused little trouble save for the perturbations in the lattice having such a large effect due to our need to run with the vertical tune within a few thousandths of the integer tune. As these problems were mostly sorted out by correcting the 6th harmonic orbit distortions which caused a large 18 theta beta wave. Also running with minimal chromaticity reduces emittance growth. There are still small beta waves which are being addressed. The timing of the pulses is still being investigated, but as each crossing causes minimal polarization loss, this is a lengthy process.

  8. Noninvasive determination of knee cartilage deformation during jumping.

    PubMed

    Filipovic, Nenad; Vulovic, Radun; Peulic, Aleksandar; Radakovic, Radivoje; Kosanic, Djordje; Ristic, Branko

    2009-01-01

    The purpose of this investigation was to use a combination of image processing, force measurements and finite element modeling to calculate deformation of the knee cartilage during jumping. Professional athletes performed jumps analyzed using a force plate and high-speed video camera system. Image processing was performed on each frame of video using a color recognition algorithm. A simplified mass-spring-damper model was utilized for determination of global force and moment on the knee. Custom software for fitting the coupling characteristics was created. Simulated results were used as input data for the finite element calculation of cartilage deformation in the athlete's knee. Computer simulation data was compared with the average experimental ground reaction forces. The results show the three-dimensional mechanical deformation distribution inside the cartilage volume. A combination of the image recognition technology, force plate measurements and the finite element cartilage deformation in the knee may be used in the future as an effective noninvasive tool for prediction of injury during jumping. Key pointsEven there are many existing mathematical models of force distribution during running or jumping (Liu et al, 1998), to our knowledge there is no interdisciplinary approach where imaging processing, finite element modeling and experimental force plate system are employed.The aim is to explore noninvasive deformation in the knee cartilage during athlete's jumping on the force plate.An original image algorithms and software were developed as well as complex mathematical models using high-performance computational power of finite element modeling together with one-dimensional dynamics model.The initial results showed cartilage deformation in the knee and future research will be focused on the methodology and more precisely determination of the stress and strain distribution in the knee cartilage during training phase of sportsman. PMID:24149600

  9. Bilateral practice improves dominant leg performance in long jump.

    PubMed

    Focke, Anne; Spancken, Sina; Stockinger, Christian; Thürer, Benjamin; Stein, Thorsten

    2016-10-01

    Benefits of bilateral practice both for the non-dominant and for the dominant body side have been shown in several studies. Thereby, most of the studies included movement tasks of the upper extremity or investigated sports games in which the ability of acting bilaterally is an essential basis for success and, thus, a bilateral practice is reasonable anyway. Individual unilaterally performed sports including movement tasks of the lower extremity are rarely investigated. Therefore, the aim of our study was to test if contralateral transfer due to bilateral practice can be found in an unilaterally performed sport including the lower extremity. We trained and tested 61 adolescent athletes in long jump to compare the jumping performance of the dominant leg after a 12-week practice period between two groups: a bilateral practice group that practiced specific long jump exercises with both the dominant and non-dominant leg and an unilateral practice group that practiced specific long jump exercises only with the dominant leg. Results showed a superior effect of bilateral practice compared to unilateral practice regarding the jumping performance of the dominant leg. The performance increase at post-test and retention-test for the dominant limb was significantly higher for the bilateral practice group (pre-to-post: 5.2%, pre-to-retention: 7.4%) compared to the unilateral practice group (pre-to-post: 3.4%, pre-to-retention: 4.5%). Thus, bilateral practice should be established in the early practice programmes of track and field athletes to improve the performance of the dominant take-off leg. PMID:26864045

  10. Verbal Instructions Acutely Affect Drop Vertical Jump Biomechanics--Implications for Athletic Performance and Injury Risk Assessments.

    PubMed

    Khuu, Steven; Musalem, Lindsay L; Beach, Tyson A C

    2015-10-01

    Biomechanical quantities acquired during the drop vertical jump (DVJ) are used in the assessment of athletic performance and injury risk. The objective was to examine the impact of different verbal instructions on spatiotemporal, kinematic, and kinetic variables commonly included in such assessments. Ten men and 10 women from local varsity and club volleyball, basketball, figure skating, and track and field teams volunteered to participate. The athletes performed DVJs after given instructions to minimize ground contact time (CT), maximize jump height (HT), and synchronously extend the lower extremity joints (EX). Between the CT, HT, and EX conditions, body segment and joint angles were compared together with characteristics of vertical ground reaction force (GRF), whole-body power output, stiffness, and center-of-mass displacement time histories. Verbal instructions were found to influence nearly all of the spatiotemporal, body segment and joint kinematic, and kinetic variables that were statistically analyzed. Particularly noteworthy was the finding that athletic performance indices (e.g., jump height, power output, vertical stiffness, and reactive strength index) and lower extremity injury risk markers (e.g., peak vertical GRF and frontal plane knee angle) were significantly different (p ≤ 0.05) between the CT, HT, and EX conditions. The findings of this study suggest that verbal instructions should be controlled and/or clearly documented when using the DVJ to assess athletic performance potential and injury risk. Moreover, practitioners who devise performance enhancement and injury prevention strategies based on DVJ assessments are advised to consider that "coaching" or "cueing" during the task execution could impact conclusions drawn. PMID:26398699

  11. Body configuration and joint moment analysis during standing long jump in 6-yr-old children and adult males.

    PubMed

    Horita, T; Kitamura, K; Kohno, N

    1991-09-01

    The purpose of the present study was to compare the body configurations and the joint function during standing long jump in 6-yr-old children and adult males. Twelve healthy adult males and eight (one male and seven females) 6-yr-old kindergartners participated in this study. Subjects performed standing long jump on a force platform with full effort. Body segment and joint angles were analyzed by high speed videography (100 frames.s-1). Using kinetic and kinematic data, joint moments, power, and work done were calculated through a free body diagram. Average standing long jump performances were +1.5 SD above Japanese norm in both adults and children. A wide range of motion of the lower limb segments during flight phase was found in the adults. In the crouch prior to take off, joint muscle power peaks appeared in the same order, and joint contribution to the total work done showed almost the same values in both adults and children. It is suggested that gross motor pattern before take off is almost accomplished by the 6-yr-old. Judging by hip joint work, adult performance was much better than that of children, since the adults exerted relatively higher negative work from the onset of preparatory movement to the point of lowest center of gravity during crouch. It was concluded that skilled 6-yr-old children have not fully developed either hip negative work during preparatory movement or body configuration in the flight phase, although gross motor pattern before take off phase was accomplished to skilled adult level. PMID:1943628

  12. Phasing a segmented telescope

    NASA Astrophysics Data System (ADS)

    Paykin, Irina; Yacobi, Lee; Adler, Joan; Ribak, Erez N.

    2015-02-01

    A crucial part of segmented or multiple-aperture systems is control of the optical path difference between the segments or subapertures. In order to achieve optimal performance we have to phase subapertures to within a fraction of the wavelength, and this requires high accuracy of positioning for each subaperture. We present simulations and hardware realization of a simulated annealing algorithm in an active optical system with sparse segments. In order to align the optical system we applied the optimization algorithm to the image itself. The main advantage of this method over traditional correction methods is that wave-front-sensing hardware and software are no longer required, making the optical and mechanical system much simpler. The results of simulations and laboratory experiments demonstrate the ability of this optimization algorithm to correct both piston and tip-tilt errors.

  13. Segmented annular combustor

    DOEpatents

    Reider, Samuel B.

    1979-01-01

    An industrial gas turbine engine includes an inclined annular combustor made up of a plurality of support segments each including inner and outer walls of trapezoidally configured planar configuration extents and including side flanges thereon interconnected by means of air cooled connector bolt assemblies to form a continuous annular combustion chamber therebetween and wherein an air fuel mixing chamber is formed at one end of the support segments including means for directing and mixing fuel within a plenum and a perforated header plate for directing streams of air and fuel mixture into the combustion chamber; each of the outer and inner walls of each of the support segments having a ribbed lattice with tracks slidably supporting porous laminated replaceable panels and including pores therein for distributing combustion air into the combustion chamber while cooling the inner surface of each of the panels by transpiration cooling thereof.

  14. Phasing a segmented telescope.

    PubMed

    Paykin, Irina; Yacobi, Lee; Adler, Joan; Ribak, Erez N

    2015-02-01

    A crucial part of segmented or multiple-aperture systems is control of the optical path difference between the segments or subapertures. In order to achieve optimal performance we have to phase subapertures to within a fraction of the wavelength, and this requires high accuracy of positioning for each subaperture. We present simulations and hardware realization of a simulated annealing algorithm in an active optical system with sparse segments. In order to align the optical system we applied the optimization algorithm to the image itself. The main advantage of this method over traditional correction methods is that wave-front-sensing hardware and software are no longer required, making the optical and mechanical system much simpler. The results of simulations and laboratory experiments demonstrate the ability of this optimization algorithm to correct both piston and tip-tilt errors. PMID:25768631

  15. Head segmentation in vertebrates

    PubMed Central

    Kuratani, Shigeru; Schilling, Thomas

    2008-01-01

    Classic theories of vertebrate head segmentation clearly exemplify the idealistic nature of comparative embryology prior to the 20th century. Comparative embryology aimed at recognizing the basic, primary structure that is shared by all vertebrates, either as an archetype or an ancestral developmental pattern. Modern evolutionary developmental (Evo-Devo) studies are also based on comparison, and therefore have a tendency to reduce complex embryonic anatomy into overly simplified patterns. Here again, a basic segmental plan for the head has been sought among chordates. We convened a symposium that brought together leading researchers dealing with this problem, in a number of different evolutionary and developmental contexts. Here we give an overview of the outcome and the status of the field in this modern era of Evo-Devo. We emphasize the fact that the head segmentation problem is not fully resolved, and we discuss new directions in the search for hints for a way out of this maze. PMID:20607135

  16. Coupling Regular Tessellation with Rjmcmc Algorithm to Segment SAR Image with Unknown Number of Classes

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Li, Y.; Zhao, Q. H.

    2016-06-01

    This paper presents a Synthetic Aperture Radar (SAR) image segmentation approach with unknown number of classes, which is based on regular tessellation and Reversible Jump Markov Chain Monte Carlo (RJMCMC') algorithm. First of all, an image domain is portioned into a set of blocks by regular tessellation. The image is modeled on the assumption that intensities of its pixels in each homogeneous region satisfy an identical and independent Gamma distribution. By Bayesian paradigm, the posterior distribution is obtained to build the region-based image segmentation model. Then, a RJMCMC algorithm is designed to simulate from the segmentation model to determine the number of homogeneous regions and segment the image. In order to further improve the segmentation accuracy, a refined operation is performed. To illustrate the feasibility and effectiveness of the proposed approach, two real SAR image is tested.

  17. Relationship between sprint ability and loaded/unloaded jump tests in elite sprinters.

    PubMed

    Loturco, Irineu; DʼAngelo, Ricardo A; Fernandes, Victor; Gil, Saulo; Kobal, Ronaldo; Cal Abad, Cesar C; Kitamura, Katia; Nakamura, Fabio Y

    2015-03-01

    The neuromechanical determinants of sprint running performance have been investigated in team sports athletes and non-elite sprinters. The aim of this study was to quantify the relationships between kinetic and performance parameters, obtained in loaded and unloaded vertical and horizontal jumps, and sprinting in elite athletes. Twenty-two sprinters performed squat jumps, countermovement jumps, horizontal jumps, and jump squats with different loads on a force platform, in addition to a 50-m sprint. Results indicated that jumping height and distance in vertical and horizontal jumps are more strongly correlated (R ≈ 0.81) to sprinting speed than the respective peak forces (R ≈ 0.36). Furthermore, the optimum load generating the maximum power in the jump squat is also highly correlated to sprint performance (R ≈ 0.72). These results reveal that vertical and horizontal jump tests may be used by coaches for assessing and monitoring qualities related to sprinting performance in elite sprinters. PMID:25162648

  18. THE EFFECTS OF SINGLE VERSUS REPEATED PLYOMETRICS ON LANDING BIOMECHANICS AND JUMPING PERFORMANCE IN MEN

    PubMed Central

    Czaplicki, A.; Sacewicz, T.; Sadowski, J.

    2014-01-01

    The aim of this study was to examine the chronic effects of single and repeated jumps training on vertical landing force (VGRF) and jump height in untrained men. The VGRF and jump height were compared after a six-week plyometric training programme containing single and repeated jumps, together with two additional parameters: landing time (LT) and range of the knee flexion during landing (KF). Thirty-six untrained physical education students with a plyometric training background were randomly assigned to a single jump group (SJG, n =12), repeated jumps group (RJG, n =12), and control group (CON, n =12). The SJG performed only single jumps, the RJG executed repeated (consecutive) jumps, whereas the CON did not perform any exercises at all. A countermovement jump (CMJ), repeated countermovement jumps (RCMJ), and a drop jump (DJ) were tested before and after the training. Only the RJG showed a significantly reduced VGRF (p < 0.05) in all tests. Both plyometric groups significantly improved (p < 0.05) their jump height in all tests. The LT was significantly greater in the RJG, compared to the SJG, in all tests. The KF was also significantly (p < 0.05) greater in the RJG than in the SJG for CMJ and RCMJ. The results suggest that repeated jumps are beneficial for simultaneous landing force reduction and jumping performance enhancement. PMID:24917684

  19. The effects of single versus repeated plyometrics on landing biomechanics and jumping performance in men.

    PubMed

    Makaruk, H; Czaplicki, A; Sacewicz, T; Sadowski, J

    2014-03-01

    The aim of this study was to examine the chronic effects of single and repeated jumps training on vertical landing force (VGRF) and jump height in untrained men. The VGRF and jump height were compared after a six-week plyometric training programme containing single and repeated jumps, together with two additional parameters: landing time (LT) and range of the knee flexion during landing (KF). Thirty-six untrained physical education students with a plyometric training background were randomly assigned to a single jump group (SJG, n =12), repeated jumps group (RJG, n =12), and control group (CON, n =12). The SJG performed only single jumps, the RJG executed repeated (consecutive) jumps, whereas the CON did not perform any exercises at all. A countermovement jump (CMJ), repeated countermovement jumps (RCMJ), and a drop jump (DJ) were tested before and after the training. Only the RJG showed a significantly reduced VGRF (p < 0.05) in all tests. Both plyometric groups significantly improved (p < 0.05) their jump height in all tests. The LT was significantly greater in the RJG, compared to the SJG, in all tests. The KF was also significantly (p < 0.05) greater in the RJG than in the SJG for CMJ and RCMJ. The results suggest that repeated jumps are beneficial for simultaneous landing force reduction and jumping performance enhancement. PMID:24917684

  20. Adsorption-driven translocation of polymer chain into nanopores

    NASA Astrophysics Data System (ADS)

    Yang, Shuang; Neimark, Alexander V.

    2012-06-01

    The polymer translocation into nanopores is generally facilitated by external driving forces, such as electric or hydrodynamic fields, to compensate for entropic restrictions imposed by the confinement. We investigate the dynamics of translocation driven by polymer adsorption to the confining walls that is relevant to chromatographic separation of macromolecules. By using the self-consistent field theory, we study the passage of a chain trough a small opening from cis to trans compartments of spherical shape with adsorption potential applied in the trans compartment. The chain transfer is modeled as the Fokker-Plank diffusion along the free energy landscape of the translocation pass represented as a sum of the free energies of cis and trans parts of the chain tethered to the pore opening. We investigate how the chain length, the size of trans compartment, the magnitude of adsorption potential, and the extent of excluded volume interactions affect the translocation time and its distribution. Interplay of these factors brings about a variety of different translocation regimes. We show that excluded volume interactions within a certain range of adsorption potentials can cause a local minimum on the free energy landscape, which is absent for ideal chains. The adsorption potential always leads to the decrease of the free energy barrier, increasing the probability of successful translocation. However, the translocation time depends non-monotonically of the magnitude of adsorption potential. Our calculations predict the existence of the critical magnitude of adsorption potential, which separates favorable and unfavorable regimes of translocation.

  1. Adsorption-driven translocation of polymer chain into nanopores.

    PubMed

    Yang, Shuang; Neimark, Alexander V

    2012-06-01

    The polymer translocation into nanopores is generally facilitated by external driving forces, such as electric or hydrodynamic fields, to compensate for entropic restrictions imposed by the confinement. We investigate the dynamics of translocation driven by polymer adsorption to the confining walls that is relevant to chromatographic separation of macromolecules. By using the self-consistent field theory, we study the passage of a chain trough a small opening from cis to trans compartments of spherical shape with adsorption potential applied in the trans compartment. The chain transfer is modeled as the Fokker-Plank diffusion along the free energy landscape of the translocation pass represented as a sum of the free energies of cis and trans parts of the chain tethered to the pore opening. We investigate how the chain length, the size of trans compartment, the magnitude of adsorption potential, and the extent of excluded volume interactions affect the translocation time and its distribution. Interplay of these factors brings about a variety of different translocation regimes. We show that excluded volume interactions within a certain range of adsorption potentials can cause a local minimum on the free energy landscape, which is absent for ideal chains. The adsorption potential always leads to the decrease of the free energy barrier, increasing the probability of successful translocation. However, the translocation time depends non-monotonically of the magnitude of adsorption potential. Our calculations predict the existence of the critical magnitude of adsorption potential, which separates favorable and unfavorable regimes of translocation. PMID:22697566

  2. Microbial translocation in the pathogenesis of HIV infection and AIDS.

    PubMed

    Marchetti, Giulia; Tincati, Camilla; Silvestri, Guido

    2013-01-01

    In pathogenic simian immunodeficiency virus (SIV) and human immunodeficiency virus (HIV) infections, the translocation of microbial products from the gastrointestinal (GI) tract to portal and systemic circulation has been proposed as a major driver of the chronic immune activation that is associated with disease progression. Consistently, microbial translocation is not present in nonpathogenic SIV infections of natural host species. In vivo studies demonstrated that HIV/SIV-associated microbial translocation results from a series of immunopathological events occurring at the GI mucosa: (i) early and severe mucosal CD4(+) depletion, (ii) mucosal immune hyperactivation/persistent inflammation; (iii) damage to the integrity of the intestinal epithelium with enterocyte apoptosis and tight junction disruption; and (iv) subverted the gut microbiome, with a predominance of opportunistic bacteria. Direct in situ evidence of microbial translocation has been provided for SIV-infected rhesus macaques showing translocated microbial products in the intestinal lamina propria and distant sites. While the mechanisms by which microbial translocation causes immune activation remain controversial, a key pathogenic event appears to be innate immunity activation via Toll-like receptors and other pathogen recognition receptors. Accumulating clinical observations suggest that microbial translocation might affect HIV disease progression, response to therapy, and non-AIDS comorbidities. Given its detrimental effect on overall immunity, several interventions to prevent/block microbial translocation are currently under investigation as novel therapeutic agents for HIV/AIDS. PMID:23297256

  3. Effect of Patterned Electrical Neuromuscular Stimulation on Vertical Jump in Collegiate Athletes

    PubMed Central

    Gulick, Dawn T.; Castel, John C.; Palermo, Francis X.; Draper, David O.

    2011-01-01

    Background: Patterned electrical neuromuscular stimulation (PENS) uses the electrical stimulation of sensory and motor nerves to achieve a skeletal muscle contraction using an electromyogram-derived functional pattern. PENS is used extensively for neuromuscular reeducation and treatment of muscle disuse atrophy. Purpose: To explore the effectiveness of PENS as applied to the quadriceps muscles on the vertical jump of an athletic population. Study Design: Experimental with control and repeated measures over time. Methods: Healthy college athletes (54 women, 75 men) were divided into 3 groups (control, n = 30; jump, n = 33; and jump with PENS, n = 63). There was no difference among groups’ height and weight. Athletes performed a baseline standing vertical jump using a vertical jump system. The control group continued its normal daily activities with no jumping tasks included. The jump groups performed 3 sets of 12 repetitions with a 2-minute rest between sets at a frequency of 3 times per week. The PENS group did the jumping with the coordination of an electrical stimulation system. Vertical jump was retested after 6 weeks of intervention and 2 weeks after cessation. Results: A 3-way repeated measures analysis of variance for time (control, jump alone, jump with PENS) revealed a significant difference (P < 0.05) for time and an interaction between time and treatment, as well as a significant difference for the PENS group from baseline to posttest and for the jump group from posttest to follow-up jump. There was no significant difference between groups for the baseline vertical jump. Conclusions: This study demonstrated that 6 weeks of vertical jump training coordinated with PENS resulted in a greater increase than jumping only or control. This pattern of stimulation with PENS in combination with jump training may positively affect jumping. PMID:23016002

  4. Rieger syndrome with de Novo reciprocal translocation t(1;4) (q23.1;q25)

    SciTech Connect

    Makita, Yoshio; Masuno, Mitsuo; Imaizumi, Kiyoshi

    1995-05-22

    We report on a boy with Rieger syndrome, who had an apparently balanced reciprocal translocation between chromosomes 1 and 4. The clinical manifestations of this patient were characterized by irregular shaped pupils with a prominent Schwalbe line and an umbilical hernia. On cytogenetic studies, he was found to have a de novo reciprocal translocation 46,XY,t(1;4) (q23.1;q25), without visible deletion. His parents had normal chromosomes. A review of both cytogenetic and genetic linkage analyses with Rieger syndrome showed that chromosome 4q was involved. This and other previous reports suggested that the gene for Rieger syndrome is mapped to the 4q25{r_arrow}4q26 segment adjoining the breakpoint. 14 refs., 3 figs., 1 tab.

  5. Polypeptide translocation by the AAA+ ClpXP protease machine

    PubMed Central

    Barkow, Sarah R.; Levchenko, Igor; Baker, Tania A.; Sauer, Robert T.

    2009-01-01

    In the AAA+ ClpXP protease, ClpX uses repeated cycles of ATP hydrolysis to pull native proteins apart and to translocate the denatured polypeptide into ClpP for degradation. Here, we probe polypeptide features important for translocation. ClpXP degrades diverse synthetic peptide substrates despite major differences in side-chain chirality, size, and polarity. Moreover, translocation occurs without a peptide –NH and with 10 methylenes between successive peptide bonds. Pulling on homopolymeric tracts of glycine, proline, and lysine also allows efficient ClpXP degradation of a stably folded protein. Thus, minimal chemical features of a polypeptide chain are sufficient for translocation and protein unfolding by the ClpX machine. These results suggest that the translocation pore of ClpX is highly elastic, allowing interactions with a wide-range of chemical groups, a feature likely to be shared by many AAA+ unfoldases. PMID:19549599

  6. Range-wide success of red-cockaded woodpecker translocations.

    SciTech Connect

    Edwards, John W.; Costa, Ralph

    2004-12-31

    Edwards, John W.; Costa, Ralph. 2004. Range-wide success of red-cockaded woodpecker translocations. In: Red-cockaded woodpecker; Road to Recovery. Proceedings of the 4th Red-cockaded woodpecker Symposium. Ralph Costa and Susan J. Daniels, eds. Savannah, Georgia. January, 2003. Chapter 6. Translocation. Pp 307-311. Abstract: Red-cockaded woodpeckers (Picoides borealis) have declined range-wide during the past century, suffering from habitat loss and the effects of fire exclusion in older southern pine forests. Red-cockaded woodpecker translocations are a potentially important tool in conservation efforts to reestablish red-cockaded woodpeckers in areas from which they have been extirpated. Currently, translocations are critical in ongoing efforts to save and restore the many existing small populations. We examined the effects of demographic and environmental factors on the range-wide success of translocations between 1989 and 1995.

  7. [Mechanism of tRNA translocation on the ribosome].

    PubMed

    Rodnina, M V; Semenkov, Iu P; Savelsbergh, A; Katunin, V I; Peske, F; Wilden, B; Wintermeyer, W

    2001-01-01

    During the translocation step of the elongation cycle of peptide synthesis two tRNAs together with the mRNA move synchronously and rapidly on the ribosome. Translocation is catalyzed by the elongation factor G (EF-G) and requires GTP hydrolysis. The fundamental biochemical features of the process were worked out in the 1970-80s, to a large part by A.S. Spirin and his colleagues. Recent results from pre-steady-state kinetic analysis and cryoelectron microscopy suggest that translocation is a multistep dynamic process that entails large-scale structural rearrangements of both ribosome and EF-G. Kinetic and thermodynamic data, together with the structural information on the conformational changes of the ribosome and of EF-G, provide a detailed mechanistic model of translocation and suggest a mechanism of translocation catalysis by EF-G. PMID:11524952

  8. Toward a structural understanding of co-translational protein translocation.

    PubMed

    Voorhees, Rebecca M; Hegde, Ramanujan S

    2016-08-01

    The translocation of most eukaryotic secreted and integral membrane proteins occurs co-translationally at the endoplasmic reticulum (ER). These nascent polypeptides are recognized on the ribosome by the signal recognition particle (SRP), targeted to the ER, and translocated across or inserted into the membrane by the Sec61 translocation channel. Structural analysis of these co-translational processes has been challenging due to the size, complexity, and flexibility of the targeting and translocation machinery. Recent technological advances in cryo-electron microscopy (cryo-EM) have resulted in increasingly powerful tools to study large, heterogeneous, and low-abundance samples. These advances are being utilized to obtain near-atomic resolution reconstructions of functional translation, targeting, and translocation intermediates, paving the way to a mechanistic understanding of protein biogenesis. PMID:27155805

  9. Multistep current signal in protein translocation through graphene nanopores.

    PubMed

    Bonome, Emma Letizia; Lepore, Rosalba; Raimondo, Domenico; Cecconi, Fabio; Tramontano, Anna; Chinappi, Mauro

    2015-05-01

    In nanopore sensing experiments, the properties of molecules are probed by the variation of ionic currents flowing through the nanopore. In this context, the electronic properties and the single-layer thickness of graphene constitute a major advantage for molecule characterization. Here we analyze the translocation pathway of the thioredoxin protein across a graphene nanopore, and the related ionic currents, by integrating two nonequilibrium molecular dynamics methods with a bioinformatic structural analysis. To obtain a qualitative picture of the translocation process and to identify salient features we performed unsupervised structural clustering on translocation conformations. This allowed us to identify some specific and robust translocation intermediates, characterized by significantly different ionic current flows. We found that the ion current strictly anticorrelates with the amount of pore occupancy by thioredoxin residues, providing a putative explanation of the multilevel current scenario observed in recently published translocation experiments. PMID:25866995

  10. Strandwise translocation of a DNA glycosylase on undamaged DNA

    SciTech Connect

    Qi, Yan; Nam, Kwangho; Spong, Marie C.; Banerjee, Anirban; Sung, Rou-Jia; Zhang, Michael; Karplus, Martin; Verdine, Gregory L.

    2012-05-14

    Base excision repair of genotoxic nucleobase lesions in the genome is critically dependent upon the ability of DNA glycosylases to locate rare sites of damage embedded in a vast excess of undamaged DNA, using only thermal energy to fuel the search process. Considerable interest surrounds the question of how DNA glycosylases translocate efficiently along DNA while maintaining their vigilance for target damaged sites. Here, we report the observation of strandwise translocation of 8-oxoguanine DNA glycosylase, MutM, along undamaged DNA. In these complexes, the protein is observed to translocate by one nucleotide on one strand while remaining untranslocated on the complementary strand. We further report that alterations of single base-pairs or a single amino acid substitution (R112A) can induce strandwise translocation. Molecular dynamics simulations confirm that MutM can translocate along DNA in a strandwise fashion. These observations reveal a previously unobserved mode of movement for a DNA-binding protein along the surface of DNA.

  11. Automatic brain tumor segmentation

    NASA Astrophysics Data System (ADS)

    Clark, Matthew C.; Hall, Lawrence O.; Goldgof, Dmitry B.; Velthuizen, Robert P.; Murtaugh, F. R.; Silbiger, Martin L.

    1998-06-01

    A system that automatically segments and labels complete glioblastoma-multiform tumor volumes in magnetic resonance images of the human brain is presented. The magnetic resonance images consist of three feature images (T1- weighted, proton density, T2-weighted) and are processed by a system which integrates knowledge-based techniques with multispectral analysis and is independent of a particular magnetic resonance scanning protocol. Initial segmentation is performed by an unsupervised clustering algorithm. The segmented image, along with cluster centers for each class are provided to a rule-based expert system which extracts the intra-cranial region. Multispectral histogram analysis separates suspected tumor from the rest of the intra-cranial region, with region analysis used in performing the final tumor labeling. This system has been trained on eleven volume data sets and tested on twenty-two unseen volume data sets acquired from a single magnetic resonance imaging system. The knowledge-based tumor segmentation was compared with radiologist-verified `ground truth' tumor volumes and results generated by a supervised fuzzy clustering algorithm. The results of this system generally correspond well to ground truth, both on a per slice basis and more importantly in tracking total tumor volume during treatment over time.

  12. [Toxic anterior segment syndrome].

    PubMed

    Cornut, P-L; Chiquet, C

    2011-01-01

    Toxic anterior segment syndrome (TASS) is a general term used to describe acute, sterile postoperative inflammation due to a non-infectious substance that accidentally enters the anterior segment at the time of surgery and mimics infectious endophthalmitis. TASS most commonly occurs acutely following anterior segment surgery, typically 12-72h after cataract extraction. Anterior segment inflammation is usually quite severe with hypopyon. Endothelial cell damage is common, resulting in diffuse corneal edema. No bacterium is isolated from ocular samples. The causes of TASS are numerous and difficult to isolate. Any device or substance used during the surgery or in the immediate postoperative period may be implicated. The major known causes include: preservatives in ophthalmic solutions, denatured ophthalmic viscosurgical devices, bacterial endotoxin, and intraocular lens-induced inflammation. Clinical features of infectious and non-infectious inflammation are initially indistinguishable and TASS is usually diagnosed and treated as acute endophthalmitis. It usually improves with local steroid treatment but may result in chronic elevation of intraocular pressure or irreversible corneal edema due to permanent damage of trabecular meshwork or endothelial cells. PMID:21176994

  13. Narrowing the DiGeorge Region (DGCR) using DGS-VCFS associated translocation breakpoints

    SciTech Connect

    Li, M.; Budarf, M.L.; Sellinger, B.

    1994-09-01

    The initial evidence linking 22q11 with DiGeorge syndrome (DGS) came from identification of DGS patients with unbalanced translocations resulting in loss of 22pter{r_arrow}q11. Molecular detection of 22q11.2 deletions in over 85% of our DGS and VCFS patient population confirms the role of 22q11 haploinsufficiency in the etiology of these two disorders. In the present study, DGS/VCFS-associated translocations are used to further refine the DGS minimal critical region. We obtained previously described cell lines: GM5878 [t(10;22)], GM5401 [t(4;22)], GM0980 [t(11;22)], and LGL6012 [t(20;22)]. Lymphoblastoid cell lines were established from two new unbalanced translocations, [t(15;22)(p11;q11)] and [t(12;22)(p13.31;q11.2)] and from a family with balanced and unbalanced forms of a t(X;22)(p22.31;q11). All probands are missing 22pter{r_arrow}q11 and have mild dysmorphia, short stature, frequent infections and developmental delay. Cleft palate was also seen in the two sibs resulting from malsegregation of the t(X;22)mat. These seven breakpoints were positioned by FISH utilizing cosmids from 22q11.2. The cosmids include the loci D22S75 (N25), D22S66 (160b), and D22S259 (R32) which we have previously used to define the DGS/VCFS commonly deleted region. The t(12;22) and t(20;22) breakpoints map distal to R32. Four translocation breakpoints map between N25 and R32: CEN - N25 - t(15;22) - t(11;22) - t(10;22) - 160b - t(4;22) - R32 - TEL. The t(X;22) breakpoint lies between the proximal flanking locus D22S36 (pH11) and N25, suggesting that genes critical to the phenotype may lie between these markers. However, the der(X) is inactivated in both sibs, raising the possibility that spreading of inactivation to the translocated, 22-derived segment may silence gene(s) distal to the breakpoint. Thus, the DGCR has been narrowed to a region between D22S36 and the t(15;22) breakpoint. This enables us to narrow the search for the critical gene(s) deleted in patients with DGS and VCFS.

  14. Translocations of amphibians: Proven management method or experimental technique

    USGS Publications Warehouse

    Seigel, Richard A.; Dodd, C. Kenneth, Jr.

    2002-01-01

    In an otherwise excellent review of metapopulation dynamics in amphibians, Marsh and Trenham (2001) make the following provocative statements (emphasis added): If isolation effects occur primarily in highly disturbed habitats, species translocations may be necessary to promote local and regional population persistence. Because most amphibians lack parental care, they areprime candidates for egg and larval translocations. Indeed, translocations have already proven successful for several species of amphibians. Where populations are severely isolated, translocations into extinct subpopulations may be the best strategy to promote regional population persistence. We take issue with these statements for a number of reasons. First, the authors fail to cite much of the relevant literature on species translocations in general and for amphibians in particular. Second, to those unfamiliar with current research in amphibian conservation biology, these comments might suggest that translocations are a proven management method. This is not the case, at least in most instances where translocations have been evaluated for an appropriate period of time. Finally, the authors fail to point out some of the negative aspects of species translocation as a management method. We realize that Marsh and Trenham's paper was not concerned primarily with translocations. However, because Marsh and Trenham (2001) made specific recommendations for conservation planners and managers (many of whom are not herpetologists or may not be familiar with the pertinent literature on amphibians), we believe that it is essential to point out that not all amphibian biologists are as comfortable with translocations as these authors appear to be. We especially urge caution about advocating potentially unproven techniques without a thorough review of available options.

  15. Minimizing the cost of translocation failure with decision-tree models that predict species' behavioral response in translocation sites.

    PubMed

    Ebrahimi, Mehregan; Ebrahimie, Esmaeil; Bull, C Michael

    2015-08-01

    The high number of failures is one reason why translocation is often not recommended. Considering how behavior changes during translocations may improve translocation success. To derive decision-tree models for species' translocation, we used data on the short-term responses of an endangered Australian skink in 5 simulated translocations with different release conditions. We used 4 different decision-tree algorithms (decision tree, decision-tree parallel, decision stump, and random forest) with 4 different criteria (gain ratio, information gain, gini index, and accuracy) to investigate how environmental and behavioral parameters may affect the success of a translocation. We assumed behavioral changes that increased dispersal away from a release site would reduce translocation success. The trees became more complex when we included all behavioral parameters as attributes, but these trees yielded more detailed information about why and how dispersal occurred. According to these complex trees, there were positive associations between some behavioral parameters, such as fight and dispersal, that showed there was a higher chance, for example, of dispersal among lizards that fought than among those that did not fight. Decision trees based on parameters related to release conditions were easier to understand and could be used by managers to make translocation decisions under different circumstances. PMID:25737134

  16. AGS Fast spin resonance jump, magnets and power supplies

    SciTech Connect

    Glenn,J.W.; Huang, H.; Liaw, C. J.; Marneris, I.; Meng, W.; Mi, J. L.; Rosas, P.; Sandberg, J.; Tuozzolo, J.; Zhang, A.

    2009-05-04

    In order to cross more rapidly the 82 weak spin resonances caused by the horizontal tune and the partial snakes, we plan to jump the horizontal tune 82 times during the acceleration of polarized protons. The current in the magnets creating this tune jump will rise in 100 {micro}s, hold flat for about 4 ms and fan to zero in 100 {micro}s. Laminated beam transport quadrupole magnets have been recycled by installing new two turn coils and longitudinal laminated pole tip shims that reduce inductance and power supply current. The power supply uses a high voltage capacitor discharge to raise the magnet current, which is then switched to a low voltage supply, and then the current is switched back to the high voltage capacitor to zero the current. The current in each of the magnet pulses must match the order of magnitude change in proton momentum during the acceleration cycle. The magnet, power supply and operational experience are described.

  17. Mechanical analysis of Drosophila indirect flight and jump muscles

    PubMed Central

    Swank, Douglas M.

    2011-01-01

    The genetic advantages of Drosophila make it a very appealing choice for investigating muscle development, muscle physiology and muscle protein structure and function. To take full advantage of this model organism, it has been vital to develop isolated Drosophila muscle preparations that can be mechanically evaluated. We describe techniques to isolate, prepare and mechanically analyze skinned muscle fibers from two Drosophila muscle types, the indirect flight muscle and the jump muscle. The function of the indirect flight muscle is similar to vertebrate cardiac muscle, to generate power in an oscillatory manner. The indirect flight muscle is ideal for evaluating the influence of protein mutations on muscle and cross-bridge stiffness, oscillatory power, and deriving cross-bridge rate constants. Jump muscle physiology and structure are more similar to skeletal vertebrate muscle than indirect flight muscle, and it is ideal for measuring maximum shortening velocity, force-velocity characteristics and steady-state power generation. PMID:22079350

  18. The temperature jump at a growing ice-water interface

    NASA Astrophysics Data System (ADS)

    Elif Genceli Güner, F.; Wåhlin, Johan; Hinge, Mogens; Kjelstrup, Signe

    2015-02-01

    During an ice growth rate of around 0.02 mm/s, we report a temperature jump at an ice-water interface above 0 °C up to 1.68 °C (0.01 ± °C), as measured with thermochromatic-liquid-crystals. This gives experimental proof for the existence of an interfacial temperature jump during a liquid-solid phase transition, confirming similar results for liquid-vapour transition, and supporting idea of the surface as a separate thermodynamic system. The fact that there is no continuity in intensive variables across the interface, unlike what is assumed in standard engineering models, has a bearing on the understanding and modelling of coupled heat and mass transport at interfaces in nature and man-made applications.

  19. Frequency jumps in single chip microwave LC oscillators

    SciTech Connect

    Gualco, Gabriele; Grisi, Marco; Boero, Giovanni

    2014-12-15

    We report on the experimental observation of oscillation frequency jumps in microwave LC oscillators fabricated using standard complementary metal-oxide-semiconductor technologies. The LC oscillators, operating at a frequency of about 20 GHz, consist of a single turn planar coil, a metal-oxide-metal capacitor, and two cross-coupled metal-oxide-semiconductor field effect transistors used as negative resistance network. At 300 K as well as at 77 K, the oscillation frequency is a continuous function of the oscillator bias voltage. At 4 K, frequency jumps as large as 30 MHz are experimentally observed. This behavior is tentatively attributed to the emission and capture of single electrons from defects and dopant atoms.

  20. Insider Models with Finite Utility in Markets with Jumps

    SciTech Connect

    Kohatsu-Higa, Arturo; Yamazato, Makoto

    2011-10-15

    In this article we consider, under a Levy process model for the stock price, the utility optimization problem for an insider agent whose additional information is the final price of the stock blurred with an additional independent noise which vanishes as the final time approaches. Our main interest is establishing conditions under which the utility of the insider is finite. Mathematically, the problem entails the study of a 'progressive' enlargement of filtration with respect to random measures. We study the jump structure of the process which leads to the conclusion that in most cases the utility of the insider is finite and his optimal portfolio is bounded. This can be explained financially by the high risks involved in models with jumps.

  1. Mechanical manifestations of rare atomic jumps in dynamic force microscopy

    NASA Astrophysics Data System (ADS)

    Hoffmann, R.; Baratoff, A.; Hug, H. J.; Hidber, H. R.; Löhneysen, H. v.; Güntherodt, H.-J.

    2007-10-01

    The resonance frequency and the excitation amplitude of a silicon cantilever have been measured as a function of distance to a cleaved KBr(001) surface with a low-temperature scanning force microscope (SFM) in ultrahigh vacuum. We identify two regimes of tip-sample distances. Above a site-dependent critical tip-sample distance reproducible data with low noise and no interaction-induced energy dissipation are measured. In this regime reproducible SFM images can be recorded. At closer tip-sample distances, above two distinct atomic sites, the frequency values jump between two limiting curves on a timescale of tens of milliseconds. Furthermore, additional energy dissipation occurs wherever jumps are observed. We attribute both phenomena to rarely occurring changes in the tip apex configuration which are affected by short-range interactions with the sample. Their respective magnitudes are related to each other. A specific candidate two-level system is also proposed.

  2. Frequency jumps in single chip microwave LC oscillators

    NASA Astrophysics Data System (ADS)

    Gualco, Gabriele; Grisi, Marco; Boero, Giovanni

    2014-12-01

    We report on the experimental observation of oscillation frequency jumps in microwave LC oscillators fabricated using standard complementary metal-oxide-semiconductor technologies. The LC oscillators, operating at a frequency of about 20 GHz, consist of a single turn planar coil, a metal-oxide-metal capacitor, and two cross-coupled metal-oxide-semiconductor field effect transistors used as negative resistance network. At 300 K as well as at 77 K, the oscillation frequency is a continuous function of the oscillator bias voltage. At 4 K, frequency jumps as large as 30 MHz are experimentally observed. This behavior is tentatively attributed to the emission and capture of single electrons from defects and dopant atoms.

  3. Mechanical analysis of Drosophila indirect flight and jump muscles.

    PubMed

    Swank, Douglas M

    2012-01-01

    The genetic advantages of Drosophila make it a very appealing choice for investigating muscle development, muscle physiology and muscle protein structure and function. To take full advantage of this model organism, it has been vital to develop isolated Drosophila muscle preparations that can be mechanically evaluated. We describe techniques to isolate, prepare and mechanically analyze skinned muscle fibers from two Drosophila muscle types, the indirect flight muscle and the jump muscle. The function of the indirect flight muscle is similar to vertebrate cardiac muscle, to generate power in an oscillatory manner. The indirect flight muscle is ideal for evaluating the influence of protein mutations on muscle and cross-bridge stiffness, oscillatory power, and deriving cross-bridge rate constants. Jump muscle physiology and structure are more similar to skeletal vertebrate muscle than indirect flight muscle, and it is ideal for measuring maximum shortening velocity, force-velocity characteristics and steady-state power generation. PMID:22079350

  4. Froghopper-inspired direction-changing concept for miniature jumping robots.

    PubMed

    Jung, Gwang-Pil; Cho, Kyu-Jin

    2016-01-01

    To improve the maneuverability and agility of jumping robots, several researchers have studied steerable jumping mechanisms. This steering ability enables robots to reach a particular target by controlling their jumping direction. To this end, we propose a novel direction-changing concept for miniature jumping robots. The proposed concept allows robots to be steerable while exerting minimal effects on jumping performance. The key design principles were adopted from the froghopper's power-producing hind legs and the moment cancellation accomplished by synchronized leg operation. These principles were applied via a pair of symmetrically positioned legs and conventional gears, which were modeled on the froghopper's anatomy. Each leg has its own thrusting energy, which improves jumping performance by allowing the mechanism to thrust itself with both power-producing legs. Conventional gears were utilized to simultaneously operate the legs and cancel out the moments that they induce, which minimizes body spin. A prototype to verify the concept was built and tested by varying the initial jumping posture. Three jumping postures (synchronous, asynchronous, and single-legged) were tested to investigate how synchronization and moment cancelling affect jumping performance. The results show that synchronous jumping allows the mechanism to change direction from -40° to 40°, with an improved take-off speed. The proposed concept can only be steered in a limited range of directions, but it has potential for use in miniature jumping robots that can change jumping direction with a minimal drop in jumping performance. PMID:27625411

  5. Does gymnastics practice improve vertical jump reliability from the age of 8 to 10 years?

    PubMed

    Marina, Michel; Torrado, Priscila

    2013-01-01

    The objective of this study was to confirm whether gymnastics practice from a young age can induce greater vertical jump reliability. Fifty young female gymnasts (8.84 ± 0.62 years) and 42 females in the control group (8.58 ± 0.92 years) performed the following jump tests on a contact mat: squat jump, countermovement jump, countermovement jump with arm swing and drop jump from heights of 40 and 60 cm. The two testing sessions had three trials each and were separated by one week. A 2 (groups) × 2 (sessions) × 3 (trials) repeated measures analysis of variance (ANOVA) and a test-retest correlation analysis were used to study the reliability. There was no systematic source of error in either group for non-plyometric jumps such as squat jump, countermovement jump, and countermovement jump with arm swing. A significant group per trial interaction revealed a learning effect in gymnasts' drop jumps from 40 cm height. Additionally, the test-retest correlation analysis and the higher minimum detectable error suggest that the quick drop jump technique was not fully consolidated in either group. At an introductory level of gymnastics and between the ages of 8-10 years, the condition of being a gymnast did not lead to conclusively higher reliability, aside from better overall vertical jump performance. PMID:23414426

  6. Magnetohydrodynamic Jump Conditions for Oblique Relativistic Shocks with Gyrotropic Pressure

    NASA Technical Reports Server (NTRS)

    Double, Glen P.; Baring, Matthew G.; Jones, Frank C.; Ellison, Donald C.

    2003-01-01

    Shock jump conditions, i.e., the specification of the downstream parameters of the gas in terms of the upstream parameters, are obtained for steady-state, plane shocks with oblique magnetic fields and arbitrary flow speeds. This is done by combining the continuity of particle number flux and the electromagnetic boundary conditions at the shock with the magnetohydrodynamic conservation laws derived from the stress-energy tensor. For ultrarelativistic and nonrelativistic shocks, the jump conditions may be solved analytically. For mildly relativistic shocks, analytic solutions are obtained for isotropic pressure using an approximation for the adiabatic index that is valid in high sonic Mach number cases. Examples assuming isotropic pressure illustrate how the shock compression ratio depends on the shock speed and obliquity. In the more general case of gyrotropic pressure, the jump conditions cannot be solved analytically with- out additional assumptions, and the effects of gyrotropic pressure are investigated by parameterizing the distribution of pressure parallel and perpendicular to the magnetic field. Our numerical solutions reveal that relatively small departures from isotropy (e.g., approximately 20%) produce significant changes in the shock compression ratio, r , at all shock Lorentz factors, including ultrarelativistic ones, where an analytic solution with gyrotropic pressure is obtained. In particular, either dynamically important fields or significant pressure anisotropies can incur marked departures from the canonical gas dynamic value of r = 3 for a shocked ultrarelativistic flow and this may impact models of particle acceleration in gamma-ray bursts and other environments where relativistic shocks are inferred. The jump conditions presented apply directly to test-particle acceleration, and will facilitate future self-consistent numerical modeling of particle acceleration at oblique, relativistic shocks; such models include the modification of the fluid

  7. Soap film dynamics and topological jumps under continuous deformation

    NASA Astrophysics Data System (ADS)

    Moffatt, Keith

    2015-11-01

    Consider the dynamics of a soap-film bounded by a flexible wire (or wires) which can be continuously and slowly deformed. At each instant the soap-film relaxes in quasi-static manner to a minimum-area (i.e. minimum-energy) state compatible with the boundary configuration. This can however pass through a critical configuration at which a topological jump is inevitable. We have studied an interesting example of this behaviour: the jump of a one-sided (Möbius strip) soap-film to a two-sided film as the boundary is unfolded and untwisted from the double cover of a circle. The nature of this jump will be demonstrated and explained. More generally, dynamical systems have a natural tendency to relax through dissipative processes to a minimum-energy state, subject to any relevant constraints. An example is provided by the relaxation of a magnetic field in a perfectly conducting but viscous fluid, subject to the constraint that the magnetic field lines are frozen in the fluid. One may infer the existence of magnetostatic equilibria (and analogous steady Euler flows) of arbitrary field-line topology. In general, discontinuities (current sheets) appear during this relaxation process, and this is where reconnection of field-lines (with associated change of topology) can occur. Just as for the soap film, slow change of boundary conditions can lead to critical conditions in which such topological jumps are inevitable. (Work in collaboration with Ray Goldstein, Adriana Pesci, Renzo Ricca and Gareth Alexander.) This work was supported by Engineering and Physical Sciences Research Council Grant EP/I036060/1.

  8. Photoreceptor Pathology in the X-Linked Retinoschisis (XLRS) Mouse Results in Delayed Rod Maturation and Impaired Light Driven Transducin Translocation

    PubMed Central

    Ziccardi, Lucia; Vijayasarathy, Camasamudram; Bush, Ronald A.; Sieving, Paul A.

    2014-01-01

    Light-activated movement of transducin-α (Gαt1) from rod photoreceptor outer segments (ROS) into inner segments (IS) enables rods to rapidly adapt to changes in light intensity. The threshold light intensity at which Gαt1 translocates from ROS into IS is primarily determined by the rates of activation and inactivation of Gαt1. Loss- of- expression of the retina specific cell surface protein, retinoschsin (Rs1-KO), led to a dramatic 3–10 fold increase, depending on age, in the luminance threshold for transducin translocation from ROS into IS compared with wild-type control. In contrast, arrestin translocated from IS into ROS at the same light intensity both in WT and Rs1-KO mice. Biochemical changes, including reduced transducin protein levels and enhanced transducin GTPase activity, explain the shift in light intensity threshold for Gαt1 translocation in Rs1-KO mice. These changes in Rs1-KO mice were also associated with age related alterations in photoreceptor morphology and transcription factor expression that suggest delayed photoreceptor maturation. PMID:24664744

  9. [Establishment of the intestinal microflora and regulation of bacterial translocation after caffeine citrate treatment during postnatal period in rat].

    PubMed

    Moumen Chentouf, W; Tir Touil Meddah, A; Léké, A; Mullié, C; Krim, G; Canarelli, J-P; Meddah, B

    2012-10-01

    To relieve respiratory problems such as apnea in newborns, caffeine citrate is the drug of choice because of its good tolerance and therapeutic index. However, its impact on the intestinal microbial ecosystem and on bacterial translocation in the neonatal period remains insufficiently investigated. Therefore, the objective of this study was to evaluate the effects of caffeine citrate on the establishment of the intestinal microflora and bacterial translocation in rats from birth to the 30th day of life. Newborn Wistar rats were divided into four groups of 14 animals, each subdivided into a control group receiving a placebo (12mL tap water/kg/day) and another treated with caffeine citrate (12mg/kg/day). The animals were nursed by their mothers and weighed daily. A group of 14 rats was killed at birth and after 10, 20, or 30 days of life. Organs in which translocation was assessed (liver, lungs, spleen, and kidneys) and various fragments of intestine (duodenum, jejunum, ileum, and colon) were surgically removed. The bacteriological analysis performed involved enumeration of the total microflora, staphylococci, enterobacteria, and lactobacilli. From the 10th day, caffeine was shown to significantly decrease the weight of treated animals as compared with controls (P<0.05). However, caffeine treatment did not drastically alter the kinetics of establishment of the intestinal microflora as only enterobacteria were found to be significantly lower in any intestinal segment of the treated group (P<0.05). Moreover, from the 20th day of life, caffeine citrate significantly downregulated bacterial translocation of both Gram-positive and -negative bacteria (P<0.05). This preliminary study on the effects of treatment with caffeine citrate may open opportunities in clinical pediatrics; the treatment will remain partially effective in preventing bacterial translocation in the neonatal period. PMID:22920890

  10. Jumping-Droplet-Enhanced Condensation on Scalable Superhydrophobic Nanostructured Surfaces

    SciTech Connect

    Miljkovic, N; Enright, R; Nam, Y; Lopez, K; Dou, N; Sack, J; Wang, E

    2013-01-09

    When droplets coalesce on a superhydrophobic nanostructured surface, the resulting droplet can jump from the surface due to the release of excess surface energy. If designed properly, these superhydrophobic nanostructured surfaces can not only allow for easy droplet removal at micrometric length scales during condensation but also promise to enhance heat transfer performance. However, the rationale for the design of an ideal nanostructured surface as well as heat transfer experiments demonstrating the advantage of this jumping behavior are lacking. Here, we show that silanized copper oxide surfaces created via a simple fabrication method can achieve highly efficient jumping-droplet condensation heat transfer. We experimentally demonstrated a 25% higher overall heat flux and 30% higher condensation heat transfer coefficient compared to state-of-the-art hydrophobic condensing surfaces at low supersaturations (<1.12). This work not only shows significant condensation heat transfer enhancement but also promises a low cost and scalable approach to increase efficiency for applications such as atmospheric water harvesting and dehumidification. Furthermore, the results offer insights and an avenue to achieve high flux superhydrophobic condensation.

  11. Role of inertial instability in the West African monsoon jump

    NASA Astrophysics Data System (ADS)

    Cook, Kerry H.

    2015-04-01

    The West African monsoon jump is a sudden shift in the latitude of the West African precipitation maximum from the Guinean coast near 4°N into Sahel near 12°N in late June or early July. An examination of reanalyses and observations indicates that the Sahel rainy season develops smoothly and the monsoon jump occurs because of an abrupt decrease in Guinean coast rainfall. We show that this abrupt end of the coastal rainy season occurs when inertial instability develops over the region, 1 month later than it develops in the vicinity of the marine Atlantic Intertropical Convergence Zone. The reason for this delay is the presence of the African easterly jet, which places strong negative meridional zonal wind gradients over the coast to preserve the inertially stable environment. When the African easterly jet moves farther north due to the seasonal solar forcing, these gradients weaken and then reverse to satisfy the threshold condition for inertial instability; the rapid end of the Guinean coast rainy season follows. The northward movement and intensity of the African easterly jet are controlled by the seasonal development of strong meridional land surface temperature gradients and are independent of the formation of the Atlantic cold tongue. This explanation for the West African monsoon jump relates the phenomenon to the shape and location of the African continent, including the low-latitude position of the Guinean coast and the large expanse of the continent to the north.

  12. Exact-Output Tracking Theory for Systems with Parameter Jumps

    NASA Technical Reports Server (NTRS)

    Devasia, Santosh; Paden, Brad; Rossi, Carlo

    1997-01-01

    We consider the exact output tracking problem for systems with parameter jumps. Necessary and sufficient conditions are derived for the elimination of switching-introduced output transient. Previous works have studied this problem by developing a regulator that maintains exact tracking through parameter jumps (switches). Such techniques are, however, only applicable to minimum-phase systems. In contrast, our approach is applicable to non-minimum-phase systems and it obtains bounded but possibly non-causal solutions. If the reference trajectories are generated by an exosystem, then we develop an exact-tracking controller in a feed-back form. As in standard regulator theory, we obtain a linear map from the states of the exosystem to the desired system state which is defined via a matrix differential equation. The constant solution of this differential equation provides asymptotic tracking, and coincides with the feedback law used in standard regulator theory. The obtained results are applied to a simple flexible manipulator with jumps in the pay-load mass.

  13. Exact-Output Tracking Theory for Systems with Parameter Jumps

    NASA Technical Reports Server (NTRS)

    Devasia, Santosh; Paden, Brad; Rossi, Carlo

    1996-01-01

    In this paper we consider the exact output tracking problem for systems with parameter jumps. Necessary and sufficient conditions are derived for the elimination of switching-introduced output transient. Previous works have studied this problem by developing a regulator that maintains exact tracking through parameter jumps (switches). Such techniques are, however, only applicable to minimum-phase systems. In contrast, our approach is applicable to nonminimum-phase systems and obtains bounded but possibly non-causal solutions. If the reference trajectories are generated by an exo-system, then we develop an exact-tracking controller in a feedback form. As in standard regulator theory, we obtain a linear map from the states of the exo-system to the desired system state which is defined via a matrix differential equation. The constant solution of this differential equation provides asymptotic tracking, and coincides with the feedback law used in standard regulator theory. The obtained results are applied to a simple flexible manipulator with jumps in the pay-load mass.

  14. Aerodynamics of ski jumping flight and its control: II. Simulations

    NASA Astrophysics Data System (ADS)

    Lee, Jungil; Lee, Hansol; Kim, Woojin; Choi, Haecheon

    2015-11-01

    In a ski jumping competition, it is essential to analyze the effect of various posture parameters of a ski jumper to achieve a longer flight distance. For this purpose, we conduct a large eddy simulation (LES) of turbulent flow past a model ski jumper which is obtained by 3D scanning a ski jumper's body (Mr. Chil-Ku Kang, member of the Korean national team). The angle of attack of the jump ski is 30° and the Reynolds number based on the length of the jump ski is 540,000. The flow statistics including the drag and lift coefficients in flight are in good agreements with our own experimental data. We investigate the flow characteristics such as the flow separation and three-dimensional vortical structures and their effects on the drag and lift. In addition to LES, we construct a simple geometric model of a ski jumper where each part of the ski jumper is modeled as a canonical bluff body such as the sphere, cylinder and flat plate, to find its optimal posture. The results from this approach will be compared with those by LES and discussed. Supported by NRF program (2014M3C1B1033848, 2014R1A1A1002671).

  15. JUMP LANDING CHARACTERISTICS IN ELITE SOCCER PLAYERS WITH CEREBRAL PALSY

    PubMed Central

    Grande, I.; Mejuto, G.; Los Arcos, A.; Yanci, J.

    2013-01-01

    The aim of the present study was to analyse the parameters that characterize the vertical ground reaction force during the landing phase of a jump, and to determine the relationship among these parameters in elite soccer players with cerebral palsy (CP). Thirteen male members of the Spanish national soccer team for people with CP (mean age: 27.1 ± 4.7 years) volunteered for the study. Each participant performed three counter movement jumps. The characteristics of the first peak of the vertical ground reaction force during the landing phase of a jump, which corresponds to the forefoot contact with the ground, were similar to the results obtained in previous studies. However, a higher magnitude of rearfoot contact with the ground (F2) was observed in participants with CP than in participants without CP. Furthermore, a significant correlation between F2 magnitude and the elapsed time until its production (T2) was not observed (r = -0.474 for p = 0.102). This result implies that a landing technique based on a delay in the production of F2 might not be effective to reduce its magnitude, contrary to what has been observed in participants without CP. The absence of a significant correlation between these two parameters in the present study, and the high magnitude of F2, suggest that elite soccer players with CP should use footwear with proper cushioning characteristics. PMID:24744473

  16. Might as well jump: sound affects muscle activation in skateboarding.

    PubMed

    Cesari, Paola; Camponogara, Ivan; Papetti, Stefano; Rocchesso, Davide; Fontana, Federico

    2014-01-01

    The aim of the study is to reveal the role of sound in action anticipation and performance, and to test whether the level of precision in action planning and execution is related to the level of sensorimotor skills and experience that listeners possess about a specific action. Individuals ranging from 18 to 75 years of age--some of them without any skills in skateboarding and others experts in this sport--were compared in their ability to anticipate and simulate a skateboarding jump by listening to the sound it produces. Only skaters were able to modulate the forces underfoot and to apply muscle synergies that closely resembled the ones that a skater would use if actually jumping on a skateboard. More importantly we showed that only skaters were able to plan the action by activating anticipatory postural adjustments about 200 ms after the jump event. We conclude that expert patterns are guided by auditory events that trigger proper anticipations of the corresponding patterns of movements. PMID:24619134

  17. The length distribution of streamline segments in homogeneous isotropic decaying turbulence

    NASA Astrophysics Data System (ADS)

    Schaefer, P.; Gampert, M.; Peters, N.

    2012-04-01

    Based on the profile of the absolute value u of the velocity field ui along streamlines, the latter are partitioned into segments at their extreme points as proposed by Wang [J. Fluid Mech. 648, 183-203 (2010)], 10.1017/S0022112009993041. It is found that the boundaries of all streamline segments, i.e., points where the gradient projected in streamline direction ∂u/∂s vanishes, define a surface in space. This surface also contains all local extreme points of the scalar u-field, i.e., points where the gradient in all directions of the field of the absolute value of the velocity and thereby those of the turbulent kinetic energy (k = u2/2, where k is the instantaneous turbulent kinetic energy) vanishes. Such points also include stagnation points of the flow field, which are absolute minimum points of the turbulent kinetic energy. As local extreme points are the ending points of dissipation elements, an approach for space-filling geometries in turbulent scalar fields, such elements in the turbulent kinetic energy field also end and begin on the surface and the temporal evolution of dissipation elements and streamline segments are intimately related. Streamline segments by construction evolve both morphologically and topologically. A morphological evolution of a streamline segment corresponds to a continuous deformation when it is subject to stretching or compression and thus also implies a continuous evolution of the arclength l with time. Such an evolution does not change the number of the overall streamline segments and hence does not involve counting. On the other hand a topological evolution corresponds to either a cutting of a large segment into smaller ones or a connection of two smaller ones to form a larger segment. Such a process changes the number of segments and thus involves counting. This change of integer variables (i.e., counting) yields discrete jumps in the length of the streamline segment which are discontinuous in time. Following the terminology

  18. Altered astronaut lower limb and mass center kinematics in downward jumping following space flight

    NASA Technical Reports Server (NTRS)

    Newman, D. J.; Jackson, D. K.; Bloomberg, J. J.

    1997-01-01

    Astronauts exposed to the microgravity conditions encountered during space flight exhibit postural and gait instabilities upon return to earth that could impair critical postflight performance. The aim of the present study was to determine the effects of microgravity exposure on astronauts' performance of two-footed jump landings. Nine astronauts from several Space Shuttle missions were tested both preflight and postflight with a series of voluntary, two-footed downward hops from a 30-cm-high step. A video-based, three-dimensional motion-analysis system permitted calculation of body segment positions and joint angular displacements. Phase-plane plots of knee, hip, and ankle angular velocities compared with the corresponding joint angles were used to describe the lower limb kinematics during jump landings. The position of the whole-body center of mass (COM) was also estimated in the sagittal plane using an eight-segment body model. Four of nine subjects exhibited expanded phase-plane portraits postflight, with significant increases in peak joint flexion angles and flexion rates following space flight. In contrast, two subjects showed significant contractions of their phase-plane portraits postflight and three subjects showed insignificant overall changes after space flight. Analysis of the vertical COM motion generally supported the joint angle results. Subjects with expanded joint angle phase-plane portraits postflight exhibited larger downward deviations of the COM and longer times from impact to peak deflection, as well as lower upward recovery velocities. Subjects with postflight joint angle phase-plane contraction demonstrated opposite effects in the COM motion. The joint kinematics results indicated the existence of two contrasting response modes due to microgravity exposure. Most subjects exhibited "compliant" impact absorption postflight, consistent with decreased limb stiffness and damping, and a reduction in the bandwidth of the postural control system

  19. Segmentation of stereo terrain images

    NASA Astrophysics Data System (ADS)

    George, Debra A.; Privitera, Claudio M.; Blackmon, Theodore T.; Zbinden, Eric; Stark, Lawrence W.

    2000-06-01

    We have studied four approaches to segmentation of images: three automatic ones using image processing algorithms and a fourth approach, human manual segmentation. We were motivated toward helping with an important NASA Mars rover mission task -- replacing laborious manual path planning with automatic navigation of the rover on the Mars terrain. The goal of the automatic segmentations was to identify an obstacle map on the Mars terrain to enable automatic path planning for the rover. The automatic segmentation was first explored with two different segmentation methods: one based on pixel luminance, and the other based on pixel altitude generated through stereo image processing. The third automatic segmentation was achieved by combining these two types of image segmentation. Human manual segmentation of Martian terrain images was used for evaluating the effectiveness of the combined automatic segmentation as well as for determining how different humans segment the same images. Comparisons between two different segmentations, manual or automatic, were measured using a similarity metric, SAB. Based on this metric, the combined automatic segmentation did fairly well in agreeing with the manual segmentation. This was a demonstration of a positive step towards automatically creating the accurate obstacle maps necessary for automatic path planning and rover navigation.

  20. Insect segmentation: Genes, stripes and segments in "Hoppers".

    PubMed

    French, V

    2001-11-13

    Recent work has revealed that orthologues of several segmentation genes are expressed in the grasshopper embryo, in patterns resembling those shown in Drosophila. This suggests that, despite great differences between the embryos, a hierarchy of gap/pair-rule/segment polarity gene function may be a shared and ancestral feature of insect segmentation. PMID:11719236

  1. Jumping mechanisms of treehopper insects (Hemiptera, Auchenorrhyncha, Membracidae).

    PubMed

    Burrows, M

    2013-03-01

    The kinematics and jumping performance of treehoppers (Hemiptera, Auchenorrhyncha, Membracidae) were analysed from high speed images. The eight species analysed had an 11-fold range of body mass (3.8-41 mg) and a 2-fold range of body length (4.1-8.4 mm). Body shape was dominated by a prothoracic helmet that projected dorsally and posteriorly over the body, and in some species forwards to form a protruding horn. Jumping was propelled by rapid depression of the trochantera of the hindlegs. The hindlegs were only 30-60% longer than the front and middle legs, and 47-94% the length of the body in different species. They were slung beneath the body and moved together in the same plane. In preparation for a jump, the hindlegs were initially levated and rotated forwards so that the femora were pressed into indentations of the coxae. The tibiae were flexed about the femora and the tarsi were placed on the ground directly beneath the lateral edges of the abdomen. Movements of the front and middle legs adjusted the angle of the body relative to the ground, but for most treehoppers this angle was small, so that the body was almost parallel to the ground. The rapid depression of the hindlegs accelerated the body to take-off in 1.2 ms in the lighter treehoppers and 3.7 ms in the heavier ones. Take-off velocities of 2.1-2.7 m s(-1) were achieved and were not correlated with body mass. In the best jumps, these performances involved accelerations of 560-2450 m s(-2) (g forces of 47-250), an energy expenditure of 13.5-101 μJ, a power output of 12-32 mW and exerted a force of 9.5-29 mN. The power output per mass of muscle far exceeds the maximum active contractile limit of normal muscle. Such requirements indicate that treehoppers must be using a power amplification mechanism in a catapult-like action. Some jumps were preceded by flapping movements of the wings, but the propulsive movements of the hindlegs were crucial in achieving take-off. PMID:23155084

  2. Analyzing kinesin motor domain translocation in cultured hippocampal neurons

    PubMed Central

    Huang, Chung-Fang; Banker, Gary

    2016-01-01

    Neuronal microtubules are subject to extensive posttranslational modifications and are bound by MAPs, tip-binding proteins, and other accessory proteins. All of these features, which are difficult to replicate in vitro, are likely to influence the translocation of kinesin motors. Here we describe assays for evaluating the translocation of a population of fluorescently labeled kinesin motor domains, based on their accumulation in regions of the cell enriched in microtubule plus ends. Neurons lend themselves to these experiments because of their microtubule organization. In axons, microtubules are oriented with their plus ends out; dendrites contain a mixed population of microtubules, but those near the tips are also plus end out. The assays involve the expression of constitutively active kinesins that can walk processively, but that lack the autoinhibitory domain in the tail that normally prevents their binding to microtubules until they attach to vesicles. The degree to which such motor domains accumulate at neurite tips serves as a measure of the efficiency of their translocation. Although these assays cannot provide the kind of quantitative kinetic information obtained from in vitro assays, they offer a simple way to examine kinesin translocation in living neurons. They can be used to compare the translocation efficiency of different kinesin motors and to evaluate how mutations or posttranslational modifications within the motor domain influence kinesin translocation. Changes to motor domain accumulation in these assays can also serve as readout for changes in the microtubule cytoskeleton that affect kinesin translocation. PMID:26794516

  3. Forced Translocation of Polymer through Nanopore: Deterministic Model and Simulations

    NASA Astrophysics Data System (ADS)

    Wang, Yanqian; Panyukov, Sergey; Liao, Qi; Rubinstein, Michael

    2012-02-01

    We propose a new theoretical model of forced translocation of a polymer chain through a nanopore. We assume that DNA translocation at high fields proceeds too fast for the chain to relax, and thus the chain unravels loop by loop in an almost deterministic way. So the distribution of translocation times of a given monomer is controlled by the initial conformation of the chain (the distribution of its loops). Our model predicts the translocation time of each monomer as an explicit function of initial polymer conformation. We refer to this concept as ``fingerprinting''. The width of the translocation time distribution is determined by the loop distribution in initial conformation as well as by the thermal fluctuations of the polymer chain during the translocation process. We show that the conformational broadening δt of translocation times of m-th monomer δtm^1.5 is stronger than the thermal broadening δtm^1.25 The predictions of our deterministic model were verified by extensive molecular dynamics simulations

  4. Does translocation influence physiological stress in the desert tortoise?

    USGS Publications Warehouse

    Drake, K.K.; Nussear, K.E.; Esque, T.C.; Barber, A.M.; Vittum, K.M.; Medica, P.A.; Tracy, C.R.; Hunter, K.W.

    2012-01-01

    Wildlife translocation is increasingly used to mitigate disturbances to animals or habitat due to human activities, yet little is known about the extent to which translocating animals causes stress. To understand the relationship between physiological stress and translocation, we conducted a multiyear study (2007–2009) using a population of desert tortoises (Gopherus agassizii) near Fort Irwin, California. Blood samples were collected from adult tortoises in three treatment groups (resident, translocated and control) for 1 year prior to and 2 years after translocation. Samples were analyzed by radioimmunoassay for plasma total corticosterone (CORT), a glucocorticoid hormone commonly associated with stress responses in reptiles. CORT values were analyzed in relation to potential covariates (animal sex, date, behavior, treatment, handling time, air temperature, home-range size, precipitation and annual plant production) among seasons and years. CORT values in males were higher than in females, and values for both varied monthly throughout the activity season and among years. Year and sex were strong predictors of CORT, and translocation explained little in terms of CORT. Based on these results, we conclude that translocation does not elicit a physiological stress response in desert tortoises.

  5. Reciprocal translocations in Saccharomyces cerevisiae formed by nonhomologous end joining.

    PubMed

    Yu, Xin; Gabriel, Abram

    2004-02-01

    Reciprocal translocations are common in cancer cells, but their creation is poorly understood. We have developed an assay system in Saccharomyces cerevisiae to study reciprocal translocation formation in the absence of homology. We induce two specific double-strand breaks (DSBs) simultaneously on separate chromosomes with HO endonuclease and analyze the subsequent chromosomal rearrangements among surviving cells. Under these conditions, reciprocal translocations via nonhomologous end joining (NHEJ) occur at frequencies of approximately 2-7 x 10(-5)/cell exposed to the DSBs. Yku80p is a component of the cell's NHEJ machinery. In its absence, reciprocal translocations still occur, but the junctions are associated with deletions and extended overlapping sequences. After induction of a single DSB, translocations and inversions are recovered in wild-type and rad52 strains. In these rearrangements, a nonrandom assortment of sites have fused to the DSB, and their junctions show typical signs of NHEJ. The sites tend to be between open reading frames or within Ty1 LTRs. In some cases the translocation partner is formed by a break at a cryptic HO recognition site. Our results demonstrate that NHEJ-mediated reciprocal translocations can form in S. cerevisiae as a consequence of DSB repair. PMID:15020464

  6. Globus pallidus internal segment.

    PubMed

    Nambu, Atsushi

    2007-01-01

    The internal segment of the globus pallidus (GP(i)) gathers many bits of information including movement-related activity from the striatum, external segment of the globus pallidus (GP(e)), and subthalamic nucleus (STN), and integrates them. The GP(i) receives rich GABAergic inputs from the striatum and GP(e), and gamma-aminobutyric acid (GABA) receptors are distributed in the GP(i) in a specific manner. Thus, inputs from the striatum and GP(e) may control GP(i) activity in a different way. The GP(i) finally conveys processed information outside the basal ganglia. Changes in GABAergic neurotransmission have been reported in movement disorders and suggested to play an important role in the pathophysiology of the symptoms. PMID:17499112

  7. Segmented vortex flaps

    NASA Technical Reports Server (NTRS)

    Rao, D. M.

    1983-01-01

    Segmented vortex flaps were suggested as a means of delaying the vortex spill-over causing thrust loss over the outboard region of single-panel flaps. Also proposed was hinge-line setback for exploiting leading-edge suction in conjunction with vortex flaps to improve the overall thrust per unit flap area. These two concepts in combination were tested on a 60-deg cropped delta wing model. Significant improvement in flap efficiency was indicated by a reduction of the flap/wing area from 11.4% of single-panel flap to 6.3% of a two segment delta flap design, with no lift/drag penalty at lift coefficients between 0.5 and 0.7. The more efficient vortex flap arrangement of this study should benefit the performance attainable with flaps of given area on wings of moderate leading-edge sweep.

  8. Segmented Thermal Barrier Coating

    NASA Technical Reports Server (NTRS)

    Smialek, James L. (Inventor)

    2001-01-01

    The article has a macro-segmented thermal barrier coating due to the presence of a pattern of three-dimensional features. The features may be a series of raised ribs formed on the substrate surface and being spaced from 0.05 inches to 0.30 apart. The ribs have a width ranging from 0.005 inches to 0.02 inches, and a height ranging from 25% to 100% of the thickness of the barrier coating. Alternately, the features may be a similar pattern of grooves formed in the surface of the substrate. Other embodiments provide segmentation by grooves or ribs in the bond coat or alternately grooves formed in the thermal barrier layer.

  9. Jumping sans legs: does elastic energy storage by the vertebral column power terrestrial jumps in bony fishes?

    PubMed

    Ashley-Ross, Miriam A; Perlman, Benjamin M; Gibb, Alice C; Long, John H

    2014-02-01

    Despite having no obvious anatomical modifications to facilitate movement over land, numerous small fishes from divergent teleost lineages make brief, voluntary terrestrial forays to escape poor aquatic conditions or to pursue terrestrial prey. Once stranded, these fishes produce a coordinated and effective "tail-flip" jumping behavior, wherein lateral flexion of the axial body into a C-shape, followed by contralateral flexion of the body axis, propels the fish into a ballistic flight-path that covers a distance of multiple body lengths. We ask: how do anatomical structures that evolved in one habitat generate effective movement in a novel habitat? Within this context, we hypothesized that the mechanical properties of the axial skeleton play a critical role in producing effective overland movement, and that tail-flip jumping species demonstrate enhanced elastic energy storage through increased body flexural stiffness or increased body curvature, relative to non-jumping species. To test this hypothesis, we derived a model to predict elastic recoil work from the morphology of the vertebral (neural and hemal) spines. From ground reaction force (GRF) measurements and high-speed video, we calculated elastic recoil work, flexural stiffness, and apparent material stiffness of the body for Micropterus salmoides (a non-jumper) and Kryptolebias marmoratus (adept tail-flip jumper). The model predicted no difference between the two species in work stored by the vertebral spines, and GRF data showed that they produce the same magnitude of mass-specific elastic recoil work. Surprisingly, non-jumper M. salmoides has a stiffer body than tail-flip jumper K. marmoratus. Many tail-flip jumping species possess enlarged, fused hypural bones that support the caudal peduncle, which suggests that the localized structures, rather than the entire axial skeleton, may explain differences in terrestrial performance. PMID:24388492

  10. Translocation of threatened plants as a conservation measure in China.

    PubMed

    Liu, Hong; Ren, Hai; Liu, Qiang; Wen, XiangYing; Maunder, Michael; Gao, JiangYun

    2015-12-01

    We assessed the current status of plant conservation translocation efforts in China, a topic poorly reported in recent scientific literature. We identified 222 conservation translocation cases involving 154 species, of these 87 were Chinese endemic species and 101 (78%) were listed as threatened on the Chinese Species Red List. We categorized the life form of each species and, when possible, determined for each case the translocation type, propagule source, propagule type, and survival and reproductive parameters. A surprisingly large proportion (26%) of the conservation translocations in China were conservation introductions, largely implemented in response to large-scale habitat destruction caused by the Three-Gorge Dam and another hydropower project. Documentation and management of the translocations varied greatly. Less than half the cases had plant survival records. Statistical analyses showed that survival percentages were significantly correlated with plant life form and the type of planting materials. Thirty percent of the cases had records on whether or not individuals flowered or fruited. Results of information theoretic model selection indicated that plant life form, translocation type, propagule type, propagule source, and time since planting significantly influenced the likelihood of flowering and fruiting on the project level. We suggest that the scientific-based application of species conservation translocations should be promoted as part of a commitment to species recovery management. In addition, we recommend that the common practice of within and out of range introductions in nature reserves to be regulated more carefully due to its potential ecological risks. We recommend the establishment of a national office and database to coordinate conservation translocations in China. Our review effort is timely considering the need for a comprehensive national guideline for the newly announced nation-wide conservation program on species with extremely

  11. Can hunting of translocated nuisance Canada geese reduce local conflicts?

    USGS Publications Warehouse

    Holevinski, R.A.; Malecki, R.A.; Curtis, P.D.

    2006-01-01

    Resident Canada geese (Branta canadensis) nest or reside in the temperate latitudes of North America. In past years, translocation-the capture and subsequent release of geese at distant locations-has been used to establish resident goose populations and to reduce nuisance problems. However, with new special hunting seasons designed to target resident Canada geese, we can now evaluate translocation as a management tool when hunting is allowed at release sites. We selected 2 study sites, representative of urban and suburban locations with nuisance resident geese, in central and western New York, USA. In June 2003, we translocated 80 neck-banded adult geese, 14 radiomarked adult females, and 83 juveniles 150 km east and southwest from urban and suburban problem sites in western New York to state-owned Wildlife Management Areas. At these same capture sites, we used 151 neck-banded adult geese, 12 radiomarked females, and 100 juveniles as controls to compare dispersal movements and harvest vulnerability to translocated geese. All observations (n = 45) of translocated radiomarked geese were <20 km from release sites, in areas where hunting was permitted. Only 25 of 538 observations (4.6%) of radiomarked geese at control sites were in areas open to hunting. The remainder of observations occurred at nonhunting locations within 10 km of control sites. More translocated adult geese (23.8%) were harvested than control geese (6.6%; ??2 = 72.98, P = 0.0009). More translocated juvenile geese were harvested (22.9%) than juvenile controls (5.0%; ??2 = 72.30, P = 0.0005). Only 7 (8.8%) translocated adult geese returned to the original capture sites during Canada goose hunting seasons. Translocation of adult and juvenile geese in family groups may alleviate nuisance problems at conflict sites through increased harvest, reducing the number of birds returning in subsequent years.

  12. Mode of ATM-dependent suppression of chromosome translocation

    SciTech Connect

    Yamauchi, Motohiro; Suzuki, Keiji; Oka, Yasuyoshi; Suzuki, Masatoshi; Kondo, Hisayoshi; Yamashita, Shunichi

    2011-12-09

    Highlights: Black-Right-Pointing-Pointer We addressed how ATM suppresses frequency of chromosome translocation. Black-Right-Pointing-Pointer We found ATM/p53-dependent G1 checkpoint suppresses translocation frequency. Black-Right-Pointing-Pointer We found ATM and DNA-PKcs function in a common pathway to suppress translocation. -- Abstract: It is well documented that deficiency in ataxia telangiectasia mutated (ATM) protein leads to elevated frequency of chromosome translocation, however, it remains poorly understood how ATM suppresses translocation frequency. In the present study, we addressed the mechanism of ATM-dependent suppression of translocation frequency. To know frequency of translocation events in a whole genome at once, we performed centromere/telomere FISH and scored dicentric chromosomes, because dicentric and translocation occur with equal frequency and by identical mechanism. By centromere/telomere FISH analysis, we confirmed that chemical inhibition or RNAi-mediated knockdown of ATM causes 2 to 2.5-fold increase in dicentric frequency at first mitosis after 2 Gy of gamma-irradiation in G0/G1. The FISH analysis revealed that ATM/p53-dependent G1 checkpoint suppresses dicentric frequency, since RNAi-mediated knockdown of p53 elevated dicentric frequency by 1.5-fold. We found ATM also suppresses dicentric occurrence independently of its checkpoint role, as ATM inhibitor showed additional effect on dicentric frequency in the context of p53 depletion and Chk1/2 inactivation. Epistasis analysis using chemical inhibitors revealed that ATM kinase functions in the same pathway that requires kinase activity of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) to suppress dicentric frequency. From the results in the present study, we conclude that ATM minimizes translocation frequency through its commitment to G1 checkpoint and DNA double-strand break repair pathway that requires kinase activity of DNA-PKcs.

  13. Within-Range Translocations and Their Consequences in European Larch

    PubMed Central

    Wagner, Stefanie; Liepelt, Sascha; Gerber, Sophie; Petit, Rémy J.

    2015-01-01

    In contrast to biological invasions, translocations of individuals within a species range are understudied, due to difficulties in systematically detecting them. This results in limited knowledge about the corresponding processes and uncertainties regarding the status of extant populations. European larch, a forest tree whose fragmented native distribution is restricted to the Alps and to other Central European mountains, has been massively planted for at least 300 years. Here we focus on the genetic characterization of translocations having taken place within its native range. Microsatellite variation at 13 nuclear loci and sequence data of two mitochondrial DNA fragments were analyzed on the basis of a comprehensive range-wide population sample. Two complementary methods (Geneclass and Structure) were used to infer translocation events based on nuclear data whereas mitochondrial data were used for validation of these inferences. Using Geneclass, we found translocation events in a majority of populations. Additional cases of translocation and many instances of admixture were identified using Structure, thanks to the clear-cut ancestral genetic structure detected in this species. In particular, a strong divide between Alpine and Central European populations, also apparent at mitochondrial markers, helped uncover details on translocation events and related processes. Translocations and associated admixture events were found to be heterogeneously distributed across the species range, with a particularly high frequency in Central Europe. Furthermore, translocations frequently involved multiple geographic sources, some of which were over-represented. Our study illustrates the importance of range-wide investigations for tracing translocations back to their origins and for revealing some of their consequences. It provides some first clues for developing suitable conservation and management strategies. PMID:26000791

  14. Ski jump takeoff performance predictions for a mixed-flow, remote-lift STOVL aircraft

    NASA Technical Reports Server (NTRS)

    Birckelbaw, Lourdes G.

    1992-01-01

    A ski jump model was developed to predict ski jump takeoff performance for a short takeoff and vertical landing (STOVL) aircraft. The objective was to verify the model with results from a piloted simulation of a mixed flow, remote lift STOVL aircraft. The prediction model is discussed. The predicted results are compared with the piloted simulation results. The ski jump model can be utilized for basic research of other thrust vectoring STOVL aircraft performing a ski jump takeoff.

  15. Example based lesion segmentation

    NASA Astrophysics Data System (ADS)

    Roy, Snehashis; He, Qing; Carass, Aaron; Jog, Amod; Cuzzocreo, Jennifer L.; Reich, Daniel S.; Prince, Jerry; Pham, Dzung

    2014-03-01

    Automatic and accurate detection of white matter lesions is a significant step toward understanding the progression of many diseases, like Alzheimer's disease or multiple sclerosis. Multi-modal MR images are often used to segment T2 white matter lesions that can represent regions of demyelination or ischemia. Some automated lesion segmentation methods describe the lesion intensities using generative models, and then classify the lesions with some combination of heuristics and cost minimization. In contrast, we propose a patch-based method, in which lesions are found using examples from an atlas containing multi-modal MR images and corresponding manual delineations of lesions. Patches from subject MR images are matched to patches from the atlas and lesion memberships are found based on patch similarity weights. We experiment on 43 subjects with MS, whose scans show various levels of lesion-load. We demonstrate significant improvement in Dice coefficient and total lesion volume compared to a state of the art model-based lesion segmentation method, indicating more accurate delineation of lesions.

  16. The RNA polymerase bridge helix YFI motif in catalysis, fidelity and translocation

    PubMed Central

    Nedialkov, Yuri A.; Opron, Kristopher; Assaf, Fadi; Artsimovitch, Irina; Kireeva, Maria L.; Kashlev, Mikhail; Cukier, Robert I.; Nudler, Evgeny; Burton, Zachary F.

    2013-01-01

    The bridge α-helix in the β′ subunit of RNA polymerase (RNAP) borders the active site and may have roles in catalysis and translocation. In Escherichia coli RNAP, a bulky hydrophobic segment near the N-terminal end of the bridge helix is identified (β′ 772-YFI-774; the YFI motif). YFI is located at a distance from the active center and adjacent to a glycine hinge (β′ 778-GARKG-782) involved in dynamic bending of the bridge helix. Remarkably, amino acid substitutions in YFI significantly alter intrinsic termination, pausing, fidelity and translocation of RNAP. F773V RNAP largely ignores the λ tR2 terminator at 200 µM NTPs and is strongly reduced in λ tR2 recognition at 1 µM NTPs. F773V alters RNAP pausing and backtracking and favors misincorporation. By contrast, the adjacent Y772A substitution increases fidelity and exhibits other transcriptional defects generally opposite to those of F773V. All atom molecular dynamics simulation revealed two separate functional connections emanating from YFI explaining the distinct effects of substitutions: Y772 communicates with the active site through the link domain in the β subunit, whereas F773 communicates through the fork domain in the β subunit. I774 interacts with the F-loop, which also contacts the glycine hinge of the bridge helix. These results identified negative and positive circuits coupled at YFI and employed for regulation of catalysis, elongation, termination and translocation. PMID:23202476

  17. Slowing DNA Translocation through a Nanopore Using a Functionalized Electrode

    PubMed Central

    Krishnakumar, Padmini; Gyarfas, Brett; Song, Weisi; Sen, Suman; Zhang, Peiming; Krstić, Predrag; Lindsay, Stuart

    2013-01-01

    Nanopores were fabricated with an integrated microscale Pd electrode coated with either a hydrogen-bonding, or hydrophobic monolayer. Bare pores, or those coated with octane thiol, translocated single-stranded DNA with times of a few microseconds per base. Pores functionalized with 4(5)-(2-mercaptoethyl)-1H-imidazole-2-carboxamide slowed average translocation times, calculated as the duration of the event divided by the number of bases translocated, to about 100 microseconds per base at biases in the range of 50 to 80 mV. PMID:24161197

  18. Ribosomal Translocation: One Step Closer to the Molecular Mechanism

    PubMed Central

    Shoji, Shinichiro; Walker, Sarah E.; Fredrick, Kurt

    2010-01-01

    Protein synthesis occurs in ribosomes, the targets of numerous antibiotics. How these large and complex machines read and move along mRNA have proven to be challenging questions. In this Review, we focus on translocation, the last step of the elongation cycle in which movement of tRNA and mRNA is catalyzed by elongation factor G. Translocation entails large-scale movements of the tRNAs and conformational changes in the ribosome that require numerous tertiary contacts to be disrupted and reformed. We highlight recent progress toward elucidating the molecular basis of translocation and how various antibiotics influence tRNA–mRNA movement. PMID:19173642

  19. Segmenting the Adult Education Market.

    ERIC Educational Resources Information Center

    Aurand, Tim

    1994-01-01

    Describes market segmentation and how the principles of segmentation can be applied to the adult education market. Indicates that applying segmentation techniques to adult education programs results in programs that are educationally and financially satisfying and serve an appropriate population. (JOW)

  20. Market Segmentation for Information Services.

    ERIC Educational Resources Information Center

    Halperin, Michael

    1981-01-01

    Discusses the advantages and limitations of market segmentation as strategy for the marketing of information services made available by nonprofit organizations, particularly libraries. Market segmentation is defined, a market grid for libraries is described, and the segmentation of information services is outlined. A 16-item reference list is…

  1. Functional Segments in Tongue Movement

    ERIC Educational Resources Information Center

    Stone, Maureen; Epstein, Melissa A.; Iskarous, Khalil

    2004-01-01

    The tongue is a deformable object, and moves by compressing or expanding local functional segments. For any single phoneme, these functional tongue segments may move in similar or opposite directions, and may reach target maximum synchronously or not. This paper will discuss the independence of five proposed segments in the production of speech.…

  2. Down syndrome consequent to a cryptic maternal 12p;21q chromosome translocation

    SciTech Connect

    Scott, J.A.; Wenger, S.L.; Chakravarti, A.

    1995-03-13

    A 9-year-old, mildly mentally retarded girl presented with phenotypic manifestations of Down syndrome. G-banded chromosomal analyses of peripheral blood lymphocytes from the patient and her parents, and skin fibroblasts from the patient, did not detect any abnormality. Molecular analysis of 15 highly polymorphic chromosome 21 dinucleotide repeat markers demonstrated a partial duplication of the Down syndrome critical region (D21S55, subband 21q22.2) of maternal origin in the patient. The segmental trisomy was confirmed by FISH analysis using the cosmid probe D21S55. Further analysis demonstrated that the trisomy was due to segregation of an apparently balanced cryptic translocation from the mother. The patient`s karyotype is 46,XX,-12,tder(12)t(12;21)(p13.1;q22.2)mat. 21 refs., 3 figs., 1 tab.

  3. De Novo microdeletion on an inherited Robertsonian translocation chromosome: A cause for dysmorphism in the apparently balanced translocation carrier

    SciTech Connect

    Bonthron, D.T.; Smith, S.J.L.; Fantes, J.; Gosden, C.M.

    1993-09-01

    Robertsonian translocations are usually ascertained through abnormal children, making proposed phenotypic effects of apparently balanced translocations difficult to study in an unbiased way. From molecular genetic studies, though, some apparently balanced rearrangments are now known to be associated with phenotypic abnormalities resulting from uniparental disomy. Molecular explanations for other cases in which abnormality is seen in a balanced translocation carrier are being sought. In the present paper, an infant is described who has retarded growth, developmental delay, gross muscular hypotonia, slender habitus, frontal bossing, micrognathia, hooked nose, abundant wispy hair, and blue sclerae. Cytogenetically, she appeared to be a carrier of a balanced, paternally derived 14;21 Robertsonian translocation. Analysis of DNA polymorphisms showed that she had no paternal allele at the D14S13 locus (14q32). Study of additional DNA markers within 14q32 revealed that her previously undescribed phenotype results from an interstitial microdeletion within 14q32. Fluorescent in situ hybridization was used to show that this microdeletion had occurred de novo on the Robertsonian translocation chromosome. These observations may reactivate old suspicions of a causal association between Robertsonian translocations and de novo rearrangements in offspring; a systematic search for similar subcytogentic rearrangements in other families, in which there are phenotypically abnormal children with apparently balanced translocations, may be fruitful. The clinical and molecular genetic data presented also define a new contiguous gene syndrome due to interstitial 14q32 deletion. 42 refs., 4 figs., 1 tab.

  4. The relationship between kinematic determinants of jump and sprint performance in division I women soccer players.

    PubMed

    McCurdy, Kevin W; Walker, John L; Langford, George A; Kutz, Matt R; Guerrero, James M; McMillan, Jeremy

    2010-12-01

    The purpose of this study was to determine the relationship between measures of unilateral and bilateral jumping performance and 10- and 25-m sprint performance. Fifteen division I women soccer players (height 165 ± 2.44 cm, mass 61.65 ± 7.7 kg, age 20.19 ± 0.91 years) volunteered to participate in this study. The subjects completed a 10- and 25-m sprint test. The following jump kinematic variables were measured using accelerometry: sprint time, step length, step frequency, jump height and distance, contact time, concentric contact time, and flight time (Inform Sport Training Systems, Victoria, BC, Canada). The following jumps were completed in random order: bilateral countermovement vertical jump, bilateral countermovement horizontal jump, bilateral 40-cm drop vertical jump, bilateral 40-cm drop horizontal jump, unilateral countermovement vertical jump (UCV), unilateral countermovement horizontal jump, unilateral 20-cm drop vertical jump (UDV), and unilateral 20-cm drop horizontal jump (UDH). The trial with the best jump height or distance, reactive strength (jump height or distance/total contact time), and flight time to concentric contact time ratio (FT/CCT) was recorded to analyze the relationship between jump kinematics and sprint performance. None of the bilateral jump kinematics significantly correlated with 10- and 25-m sprint time, step length, or step frequency. Right-leg jump height (r = -0.71, p = 0.006, SEE = 0.152 seconds), FT/CCT (r = -0.58, p = 0.04, SEE = 0.176 seconds), and combined right and left-leg jump height (r = -0.61) were significantly correlated with the 25-m sprint time during the UCV. Right-leg FT/CCT was also significantly related to 25-m step length (r = 0.68, p = 0.03, SEE = 0.06 m) during the UDV. The combined right and left leg jump distance to standing height ratio during the UDH significantly correlated (r = -0.58) with 10-m sprint time. In comparison to bilateral jumps, unilateral jumps produced a stronger relationship with

  5. Multiscale model of platelet translocation and collision

    NASA Astrophysics Data System (ADS)

    Wang, Weiwei; Mody, Nipa A.; King, Michael R.

    2013-07-01

    The tethering of platelets on the injured vessel surface mediated by glycoprotein Ibα (GPIbα) - Von Willebrand factor (vWF) bonds, as well as the interaction between flowing platelets and adherent platelets, are two key events that take place immediately following blood vessel injury. This early-stage platelet deposition and accumulation triggers the initiation of hemostasis, a self-defensive mechanism to prevent the body from excessive blood loss. To understand and predict this complex process, one must integrate experimentally determined information on the mechanics and biochemical kinetics of participating receptors over very small time frames (1-1000 μs) and length scales (10-100 nm), to collective phenomena occurring over seconds and tens of microns. In the present study, a unique three dimensional multiscale computational model, Platelet Adhesive Dynamics (PAD), was applied to elucidate the unique physics of (i) a non-spherical, disk-shaped platelet interacting and tethering onto the damaged vessel wall followed by (ii) collisional interactions between a flowing platelet with a downstream adherent platelet. By analyzing numerous simulations under different physiological conditions, we conclude that the platelet's unique spheroid-shape provides heterogeneous, orientation-dependent translocation (rolling) behavior which enhances cell-wall interactions. We also conclude that platelet-platelet near field interactions are critical for cell-cell communication during the initiation of microthrombi. The PAD model described here helps to identify the physical factors that control the initial stages of platelet capture during this process.

  6. Biphasic translocation of Bax to mitochondria.

    PubMed Central

    Capano, Michela; Crompton, Martin

    2002-01-01

    Using green fluorescent protein-tagged Bax, we demonstrate that Bax is sequestered from the cytosol of cardiomyocytes in two distinct phases following the induction of apoptosis with staurosporine. In the first phase, lasting several hours, Bax removal from the cytosol was relatively small. In the second phase, Bax was very largely removed from the cytosol and sequestered into large aggregates associated with the mitochondria. To test which of the phases involved cytochrome c release, cells were transfected with a red fluorescent protein-cytochrome c fusion. The cytochrome c fusion protein was accumulated by mitochondria of healthy cells and was released by staurosporine in phase 1. When green fluorescent protein-Bax was immunoprecipitated from extracts of cells in phase 1 and phase 2, the voltage-dependent anion channel (mitochondrial outer membrane) and the adenine nucleotide translocase (mitochondrial inner membrane) were also precipitated. These data support a two-phase model of Bax translocation in which Bax targets the mitochondrial intermembrane contact sites and releases cytochrome c in the first phase, and is then packaged into large aggregates on mitochondria in the second. PMID:12097139

  7. Translocation of 40 nm diameter nanowires through the intestinal epithelium of Daphnia magna

    PubMed Central

    Mattsson, Karin; Adolfsson, Karl; Ekvall, Mikael T.; Borgström, Magnus T.; Linse, Sara; Hansson, Lars-Anders; Cedervall, Tommy; Prinz, Christelle N.

    2016-01-01

    Abstract Nanowires (NWs) have unique electrical and optical properties of value for many applications including lighting, sensing, and energy harnessing. Consumer products containing NWs increase the risk of NWs being released in the environment, especially into aquatic ecosystems through sewage systems. Daphnia magna is a common, cosmopolitan freshwater organism sensitive to toxicity tests and represents a likely entry point for nanoparticles into food webs of aquatic ecosystems. Here we have evaluated the effect of NW diameter on the gut penetrance of NWs in Daphnia magna. The animals were exposed to NWs of two diameters (40 and 80 nm) and similar length (3.6 and 3.8 μm, respectively) suspended in water. In order to locate the NWs in Daphnia, the NWs were designed to comprise one inherently fluorescent segment of gallium indium phosphide (GaInP) flanked by a gallium phosphide (GaP) segment. Daphnia mortality was assessed directly after 24 h of exposure and 7 days after exposure. Translocation of NWs across the intestinal epithelium was investigated using confocal fluorescence microscopy directly after 24 h of exposure and was observed in 89% of Daphnia exposed to 40 nm NWs and in 11% of Daphnia exposed to 80 nm NWs. A high degree of fragmentation was observed for NWs of both diameters after ingestion by the Daphnia, although 40 nm NWs were fragmented to a greater extent, which could possibly facilitate translocation across the intestinal epithelium. Our results show that the feeding behavior of animals may enhance the ability of NWs to penetrate biological barriers and that penetrance is governed by the NW diameter. PMID:27181920

  8. Translocation of 40 nm diameter nanowires through the intestinal epithelium of Daphnia magna.

    PubMed

    Mattsson, Karin; Adolfsson, Karl; Ekvall, Mikael T; Borgström, Magnus T; Linse, Sara; Hansson, Lars-Anders; Cedervall, Tommy; Prinz, Christelle N

    2016-10-01

    Nanowires (NWs) have unique electrical and optical properties of value for many applications including lighting, sensing, and energy harnessing. Consumer products containing NWs increase the risk of NWs being released in the environment, especially into aquatic ecosystems through sewage systems. Daphnia magna is a common, cosmopolitan freshwater organism sensitive to toxicity tests and represents a likely entry point for nanoparticles into food webs of aquatic ecosystems. Here we have evaluated the effect of NW diameter on the gut penetrance of NWs in Daphnia magna. The animals were exposed to NWs of two diameters (40 and 80 nm) and similar length (3.6 and 3.8 μm, respectively) suspended in water. In order to locate the NWs in Daphnia, the NWs were designed to comprise one inherently fluorescent segment of gallium indium phosphide (GaInP) flanked by a gallium phosphide (GaP) segment. Daphnia mortality was assessed directly after 24 h of exposure and 7 days after exposure. Translocation of NWs across the intestinal epithelium was investigated using confocal fluorescence microscopy directly after 24 h of exposure and was observed in 89% of Daphnia exposed to 40 nm NWs and in 11% of Daphnia exposed to 80 nm NWs. A high degree of fragmentation was observed for NWs of both diameters after ingestion by the Daphnia, although 40 nm NWs were fragmented to a greater extent, which could possibly facilitate translocation across the intestinal epithelium. Our results show that the feeding behavior of animals may enhance the ability of NWs to penetrate biological barriers and that penetrance is governed by the NW diameter. PMID:27181920

  9. Keeping your eye on the rail: gaze behaviour of horse riders approaching a jump.

    PubMed

    Hall, Carol; Varley, Ian; Kay, Rachel; Crundall, David

    2014-01-01

    The gaze behaviour of riders during their approach to a jump was investigated using a mobile eye tracking device (ASL Mobile Eye). The timing, frequency and duration of fixations on the jump and the percentage of time when their point of gaze (POG) was located elsewhere were assessed. Fixations were identified when the POG remained on the jump for 100 ms or longer. The jumping skill of experienced but non-elite riders (n = 10) was assessed by means of a questionnaire. Their gaze behaviour was recorded as they completed a course of three identical jumps five times. The speed and timing of the approach was calculated. Gaze behaviour throughout the overall approach and during the last five strides before take-off was assessed following frame-by-frame analyses. Differences in relation to both round and jump number were found. Significantly longer was spent fixated on the jump during round 2, both during the overall approach and during the last five strides (p<0.05). Jump 1 was fixated on significantly earlier and more frequently than jump 2 or 3 (p<0.05). Significantly more errors were made with jump 3 than with jump 1 (p = 0.01) but there was no difference in errors made between rounds. Although no significant correlations between gaze behaviour and skill scores were found, the riders who scored higher for jumping skill tended to fixate on the jump earlier (p = 0.07), when the horse was further from the jump (p = 0.09) and their first fixation on the jump was of a longer duration (p = 0.06). Trials with elite riders are now needed to further identify sport-specific visual skills and their relationship with performance. Visual training should be included in preparation for equestrian sports participation, the positive impact of which has been clearly demonstrated in other sports. PMID:24846055

  10. Interactive explorations of hierarchical segmentations

    NASA Technical Reports Server (NTRS)

    Tilton, James C.

    1992-01-01

    The authors report on the implementation of an interactive tool, called HSEGEXP, to interactively explore the hierarchical segmentation produced by the iterative parallel region growing (IPRG) algorithm to select the best segmentation result. This combination of the HSEGEXP tool with the IPRG algorithm amounts to a computer-assisted image segmentation system guided by human interaction. The initial application of the HSEGEXP tool is in the refinement of ground reference data based on the IPRG/HSEGEXP segmentation of the corresponding remotely sensed image data. The HSEGEXP tool is being used to help evaluate the effectiveness of an automatic 'best' segmentation process under development.

  11. Explaining the Kuiper Belt with a Jumping Planet

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-09-01

    A feature of the Kuiper Belt known as the kernel has yet to be adequately explained by solar system formation models. In a recent study, a theorist at the Southwest Research Institute proposes a new explanation for how Neptune arrived at its current orbit and how this planets migration in the early years of the solar system might have created the kernel.Orbital JumpThe kernel is a concentration of orbits within the Kuiper Belt that all have semimajor axes of roughly a 44 AU, low eccentricities, and low inclinations. How this collection of objects formed and why they exist where they do is difficult to explain with current models, however. Kernel objects arent in resonance with any of the larger bodies, so why are they concentrated at that specific distance? In this study, David Nesvorn proposes that the kernel resulted from Neptunes outward migration through the solar system.In the currently favored model of our solar systems formation, the outermost gas giant planets formed closer to the Sun and then migrated out to their current locations. Nesvorn ran a series of simulations of this migration to test the theory that a discontinuity in Neptunes movement outward i.e., a sudden jump in the planets orbital distance could explain the presence of the Kuiper Belts kernel.Results from a previous study, in which the authors evolved the four gas giant planets plus a fifth giant planet (blue) initially on an orbit between Saturn and Uranus. At 18.3 Myr, a close encounter with the fifth planet causes Neptunes orbit (pink) to jump outwards by ~0.4 AU, and the fifth planet is then ejected from the solar system by Jupiter. [Nesvorn 2015]Resonant PopulationNesvorn was successful in finding a model that reproduced the kernel, as well as other observed features of the solar system today. In his model, Neptune began its journey closer to the Sun, at a distance of roughly 24 AU, and it migrated fairly rapidly outward to about 28 AU. As it traveled, it swept up bodies in the outer

  12. DNA Translocations through Solid-State Plasmonic Nanopores

    PubMed Central

    2015-01-01

    Nanopores enable label-free detection and analysis of single biomolecules. Here, we investigate DNA translocations through a novel type of plasmonic nanopore based on a gold bowtie nanoantenna with a solid-state nanopore at the plasmonic hot spot. Plasmonic excitation of the nanopore is found to influence both the sensor signal (nanopore ionic conductance blockade during DNA translocation) and the process that captures DNA into the nanopore, without affecting the duration time of the translocations. Most striking is a strong plasmon-induced enhancement of the rate of DNA translocation events in lithium chloride (LiCl, already 10-fold enhancement at a few mW of laser power). This provides a means to utilize the excellent spatiotemporal resolution of DNA interrogations with nanopores in LiCl buffers, which is known to suffer from low event rates. We propose a mechanism based on plasmon-induced local heating and thermophoresis as explanation of our observations. PMID:25347403

  13. Translocation of α-Synuclein Expressed in Escherichia coli▿

    PubMed Central

    Ren, Guoping; Wang, Xi; Hao, Shufeng; Hu, Hongyu; Wang, Chih-chen

    2007-01-01

    α-Synuclein is a major component of Lewy bodies in Parkinson's disease. Although no signal sequence is apparent, α-synuclein expressed in Escherichia coli is mostly located in the periplasm. The possibilities that α-synuclein translocated into the periplasm across the inner membrane by the SecA or the Tat targeting route identified in bacteria and that α-synuclein was released through MscL were excluded. The signal recognition particle-dependent pathway is involved in the translocation of α-synuclein. The C-terminal 99-to-140 portion of the α-synuclein molecule plays a signal-like role for its translocation into the periplasm, cooperating with the central 61-to-95 section. The N-terminal 1-to-60 region is not required for this translocation. PMID:17277073

  14. Translocation of an Incompressible Vesicle through a Pore.

    PubMed

    Shojaei, Hamid R; Muthukumar, Murugappan

    2016-07-01

    We have derived the free energy landscape for the translocation of a single vesicle through a narrow pore by accounting for bending and stretching of the vesicle, and the deformation of the vesicle by the pore. Emergence of a free energy barrier for translocation is a general result, and the magnitude of the barrier is calculated in terms of the various material parameters. The extent of the reduction in the barrier by the presence of an external constant force is calculated. Using the Fokker-Planck formalism, we have calculated the average translocation time corresponding to the various free energy landscapes representing different parameter sets. The dependencies of the average translocation time on the strength of the external force, vesicle size, bending and stretching moduli of the vesicle, and radius and length of the pore are derived, and the computed results are discussed. PMID:27089012

  15. Translocation of an Incompressible Vesicle through a Pore

    PubMed Central

    Shojaei, Hamid R.; Muthukumar, Murugappan

    2016-01-01

    We have derived the free energy landscape for the translocation of a single vesicle through a narrow pore by accounting for bending and stretching of the vesicle, and the deformation of the vesicle by the pore. Emergence of a free energy barrier for translocation is a general result, and the magnitude of the barrier is calculated in terms of the various material parameters. The extent of the reduction in the barrier by the presence of an external constant force is calculated. Using the Fokker–Planck formalism, we have calculated the average translocation time corresponding to the various free energy landscapes representing different parameter sets. The dependencies of the average translocation time on the strength of the external force, vesicle size, bending and stretching moduli of the vesicle, and radius and length of the pore are derived, and the computed results are discussed. PMID:27089012

  16. Translocation of flexible polymersomes across pores at the nanoscale.

    PubMed

    Pegoraro, Carla; Cecchin, Denis; Madsen, Jeppe; Warren, Nicholas; Armes, Steven P; MacNeil, Sheila; Lewis, Andrew; Battaglia, Giuseppe

    2014-04-01

    Hierarchical biological systems such as tissues and organs are often characterised by highly crowded and packed environments with nanoscopic interconnections between them. Engineering nanovectors that can penetrate and diffuse across these is critical to ensure enhanced delivery and targeting. Here we demonstrate that flexible polymeric vesicles, known as polymersomes, enable the translocation of large macromolecules across both synthetic and biological porous systems. We compare the translocation across narrow pores of different polymersome formulations. We demonstrate that effective translocation depends on the right combination of mechanical properties and surface lubrication. We prove that with the effect of external gradients (e.g. osmotic pressure, capillarity, hydration, etc.) polymersomes can translocate across pores with diameters one order of magnitude smaller without breaking. We demonstrate that these properties are essential to develop effective tissue penetration and show polymersome mediated transdermal delivery of large macromolecules such as dextran and antibodies using human ex vivo skin. PMID:26828800

  17. Concurrent validity of vertical jump performance assessment systems.

    PubMed

    Castagna, Carlo; Ganzetti, Marco; Ditroilo, Massimiliano; Giovannelli, Marco; Rocchetti, Alessandro; Manzi, Vincenzo

    2013-03-01

    The aim of this study was to examine the concurrent validity of 2 portable systems for vertical jump (VJ) assessment under field conditions. The VJ flight times assessed using an optical mat (Optojump) and an accelerometer-based (Myotest) system were compared with that of a force platform. The flight times recorded during a countermovement jump (CMJ) were collected from 20 rugby players (n = 86 jumps) concurrently using the 3 tracking systems. Significant bias between the Force platform and either the Optojump (bias = 0.006 ± 0.007; 95% confidence interval [CI] 0.004-0.007 seconds) and Myotest (bias = -0.031 ± 0.021; 95% CI 0.035 to -0.026s; p < 0.0001) occurred. A nearly perfect correlation was found between force platform and Optojump (r = 0.99; 95% CI 0.098-0.99; p < 0.0001). Force platform and Myotest (r = 0.89; 95% CI 0.084-0.93; p < 0.0001) flight times showed very large association. Difference between Optojump and Myotest systems was significant (-0.036 ± 0.021 seconds; 95% CI -0.041 to -0.032; p < 0.0001), which results in Myotest mean flight time being approximately 7.2% longer than the Optojump flight time. The association between Optojump and Myotest was nearly perfect (r = 0.91, 95% CI 0.86-0.94; p < 0.0001). This study showed that the Optojump and Myotest systems possess convergent validity and can be successfully used under field conditions to assess VJ while performing a CMJ. However, caution should be exercised when interpreting data obtained from different portable systems for field measurement. PMID:22648140

  18. Increased distance of shooting on basketball jump shot.

    PubMed

    Okazaki, Victor Hugo Alves; Rodacki, André Luiz Félix

    2012-01-01

    The present study analyzed the effect of increased distance on basketball jump shot outcome and performance. Ten male expert basketball players were filmed and a number of kinematic variables analyzed during jump shot that were performed from three conditions to represent close, intermediate and far distances (2.8, 4.6, and 6.4m, respectively). Shot accuracy decreased from 59% (close) to 37% (far), in function of the task constraints (p < 0.05). Ball release height decreased (p < 0.05) from 2.46 m (close) to 2.38m (intermediate) and to 2.33m (long). Release angle also decreased (p < 0.05) when shot was performed from close (78.92°) in comparison to intermediate distances (65.60°). While, ball release velocity increased (p < 0.05) from 4.39 m/s (close) to 5.75 m·s(-1) (intermediate) to 6.89 m·s(-1) (far). These changes in ball release height, angle and velocity, related to movement performance adaptations were suggested as the main factors that influence jump shot accuracy when distance is augmented. Key pointsThe increased distance leads to greater spatial con-straint over shot movement that demands an adapta-tion of the movement for the regulation of the accu-racy and the impulse generation to release the ball.The reduction in balls release height and release angle, in addition to the increase in balls release ve-locity, were suggested as the main factors that de-creased shot accuracy with the distance increased.Players should look for release angles of shooting that provide an optimal balls release velocity to im-prove accuracy. PMID:24149195

  19. Jumping mechanisms in lacewings (Neuroptera, Chrysopidae and Hemerobiidae).

    PubMed

    Burrows, Malcolm; Dorosenko, Marina

    2014-12-01

    Lacewings launch themselves into the air by simultaneous propulsive movements of the middle and hind legs as revealed in video images captured at a rate of 1000 s(-1). These movements were powered largely by thoracic trochanteral depressor muscles but did not start from a particular preset position of these legs. Ridges on the lateral sides of the meso- and metathorax fluoresced bright blue when illuminated with ultraviolet light, suggesting the presence of the elastic protein resilin. The middle and hind legs were longer than the front legs but their femora and tibiae were narrow tubes of similar diameter. Jumps were of two types. First, those in which the body was oriented almost parallel to the ground (-7±8 deg in green lacewings, 13.7±7 deg in brown lacewings) at take-off and remained stable once animals were airborne. The wings did not move until 5 ms after take-off when flapping flight ensued. Second, were jumps in which the head pointed downwards at take-off (green lacewings, -37±3 deg; brown lacewings, -35±4 deg) and the body rotated in the pitch plane once airborne without the wings opening. The larger green lacewings (mass 9 mg, body length 10.3 mm) took 15 ms and the smaller brown lacewings (3.6 mg and 5.3 mm) 9 ms to accelerate the body to mean take-off velocities of 0.6 and 0.5 m s(-1). During their fastest jumps green and brown lacewings experienced accelerations of 5.5 or 6.3 G: , respectively. They required an energy expenditure of 5.6 or 0.7 μJ, a power output of 0.3 or 0.1 mW and exerted a force of 0.6 or 0.2 mN. The required power was well within the maximum active contractile limit of normal muscle, so that jumping could be produced by direct muscle contractions without a power amplification mechanism or an energy store. PMID:25359935

  20. Crack velocity jumps engendered by a transformational process zone

    NASA Astrophysics Data System (ADS)

    Boulbitch, A.; Korzhenevskii, A. L.

    2016-06-01

    We study a concerted propagation of a fast crack with the process zone where a rearrangement of the solid structure takes place. The latter is treated as a second-order local phase transformation. We demonstrate that the propagation of such a zone gives rise to a nonlinear frictionlike force exerted on the crack tip, resisting its propagation. Depending on the temperature, it produces three regimes of crack motion, which differ in the behavior of the crack tip process zone: (i) always existing, (ii) only emerging at a high crack speed, and (iii) flickering. We show that the latter regime exhibits crack velocity jumps.

  1. UV-induced surface electrical conductivity jump of polymer nanocomposites

    SciTech Connect

    Chen Guangxin; Miyauchi, Masahiro; Shimizu, Hiroshi

    2008-05-19

    A method of improving the electrical conductivity of polymer nanocomposites under UV irradiation was described. An anatase TiO{sub 2}-grafted carbon nanotube could function as a conductive filler and a photocatalyst when it compounds with a poly(L-lactide) to produce a composite. After UV irradiation, the decomposition of the polymer only occurred on the surface of a poly(L-lactide)/TiO{sub 2} grafted carbon nanotube composite and not on bulk, resulting in an electrical conductivity jump as high as six orders of magnitude.

  2. Multiscale integration schemes for jump-diffusion systems

    SciTech Connect

    Givon, D.; Kevrekidis, I.G.

    2008-12-09

    We study a two-time-scale system of jump-diffusion stochastic differential equations. We analyze a class of multiscale integration methods for these systems, which, in the spirit of [1], consist of a hybridization between a standard solver for the slow components and short runs for the fast dynamics, which are used to estimate the effect that the fast components have on the slow ones. We obtain explicit bounds for the discrepancy between the results of the multiscale integration method and the slow components of the original system.

  3. Adaptive changes in locust kicking and jumping behaviour during development

    PubMed

    Norman

    1995-01-01

    The hind, or metathoracic, leg of a locust is specialised, enabling it to store energy that is used to extend the tibia rapidly during kicking and jumping; behaviours which share a common motor pattern. This study describes developmental changes in kicking and jumping behaviour and relates these changes to the development of the exoskeleton and jumping performance. In mature adults and intermoult larvae, the exoskeleton is strong and kicks can readily be elicited. Before and after the adult moult, when the exoskeleton is weak, kicks can be elicited less frequently, thus avoiding skeletal damage. At these times, animals do not generate the adult motor pattern for kicking, so that extension of the tibia is powered by direct muscle contraction, rather than through the release of stored energy. The muscles of all newly moulted animals are capable of generating sufficient force to damage the leg, but 14 days later the muscles can rarely generate sufficient force to damage the leg. To mimic the forces generated during the preparation for a kick, when the flexor and extensor tibiae muscles co-contract, the extensor muscle was stimulated electrically at a range of frequencies and the nature and occurrence of the resulting mechanical damage to components of the skeleton were assessed over a 14 day period following the adult moult. In newly moulted animals, the proximal femur partially collapses and thus protects the leg from damage before the muscles generate sufficient force to damage chronically other components of the leg. This partial collapse of the femur is reversible when the extensor muscle is activated at low frequency, but high frequencies cause permanent damage. The muscles of all animals 1 day after the moult are also capable of generating sufficient force to damage the leg, but the proximal tibia breaks most commonly in the region where the extensor muscle apodeme attaches. 5 days after the moult, the muscles in only 50 % of animals can damage the leg and most

  4. Light-regulated translocation of signaling proteins in Drosophila photoreceptors

    PubMed Central

    Frechter, Shahar; Minke, Baruch

    2007-01-01

    Illumination of Drosophila photoreceptor cells induces multi-facet responses, which include generation of the photoreceptor potential, screening pigment migration and translocation of signaling proteins which is the focus of recent extensive research. Translocation of three signaling molecules is covered in this review: (1) Light-dependent translocation of arrestin from the cytosol to the signaling membrane, the rhabdomere, determines the lifetime of activated rhodopsin. Arrestin translocates in PIP3 and NINAC myosin III dependent manner, and specific mutations which disrupt the interaction between arrestin and PIP3 or NINAC also impair the light-dependant translocation of arrestin and the termination of the response to light. (2) Activation of Drosophila visual G protein, DGq, causes a massive and reversible, translocation of the α subunit from the signaling membrane to the cytosol, accompanied by activity-dependent architectural changes. Analysis of the translocation and the recovery kinetics of DGqα in wild-type flies and specific visual mutants indicated that DGqα is necessary but not sufficient for the architectural changes. (3) The TRP-like (TRPL) but not TRP channels translocate in a light-dependent manner between the rhabdomere and the cell body. As a physiological consequence of this light-dependent modulation of the TRP/TRPL ratio, the photoreceptors of dark-adapted flies operate at a wider dynamic range, which allows the photoreceptors enriched with TRPL to function better in darkness and dim background illumination. Altogether, signal-dependent movement of signaling proteins plays a major role in the maintenance and function of photoreceptor cells. PMID:16458490

  5. Slowing DNA Translocation in a Nanofluidic Field-Effect Transistor.

    PubMed

    Liu, Yifan; Yobas, Levent

    2016-04-26

    Here, we present an experimental demonstration of slowing DNA translocation across a nanochannel by modulating the channel surface charge through an externally applied gate bias. The experiments were performed on a nanofluidic field-effect transistor, which is a monolithic integrated platform featuring a 50 nm-diameter in-plane alumina nanocapillary whose entire length is surrounded by a gate electrode. The field-effect transistor behavior was validated on the gating of ionic conductance and protein transport. The gating of DNA translocation was subsequently studied by measuring discrete current dips associated with single λ-DNA translocation events under a source-to-drain bias of 1 V. The translocation speeds under various gate bias conditions were extracted by fitting event histograms of the measured translocation time to the first passage time distributions obtained from a simple 1D biased diffusion model. A positive gate bias was observed to slow the translocation of single λ-DNA chains markedly; the translocation speed was reduced by an order of magnitude from 18.4 mm/s obtained under a floating gate down to 1.33 mm/s under a positive gate bias of 9 V. Therefore, a dynamic and flexible regulation of the DNA translocation speed, which is vital for single-molecule sequencing, can be achieved on this device by simply tuning the gate bias. The device is realized in a conventional semiconductor microfabrication process without the requirement of advanced lithography, and can be potentially further developed into a compact electronic single-molecule sequencer. PMID:27019102

  6. Elongation factor G initiates translocation through a power stroke.

    PubMed

    Chen, Chunlai; Cui, Xiaonan; Beausang, John F; Zhang, Haibo; Farrell, Ian; Cooperman, Barry S; Goldman, Yale E

    2016-07-01

    During the translocation step of prokaryotic protein synthesis, elongation factor G (EF-G), a guanosine triphosphatase (GTPase), binds to the ribosomal PRE-translocation (PRE) complex and facilitates movement of transfer RNAs (tRNAs) and messenger RNA (mRNA) by one codon. Energy liberated by EF-G's GTPase activity is necessary for EF-G to catalyze rapid and precise translocation. Whether this energy is used mainly to drive movements of the tRNAs and mRNA or to foster EF-G dissociation from the ribosome after translocation has been a long-lasting debate. Free EF-G, not bound to the ribosome, adopts quite different structures in its GTP and GDP forms. Structures of EF-G on the ribosome have been visualized at various intermediate steps along the translocation pathway, using antibiotics and nonhydolyzable GTP analogs to block translocation and to prolong the dwell time of EF-G on the ribosome. However, the structural dynamics of EF-G bound to the ribosome have not yet been described during normal, uninhibited translocation. Here, we report the rotational motions of EF-G domains during normal translocation detected by single-molecule polarized total internal reflection fluorescence (polTIRF) microscopy. Our study shows that EF-G has a small (∼10°) global rotational motion relative to the ribosome after GTP hydrolysis that exerts a force to unlock the ribosome. This is followed by a larger rotation within domain III of EF-G before its dissociation from the ribosome. PMID:27313204

  7. Molecular studies of translocations and trisomy involving chromosome 13

    SciTech Connect

    Robinson, W.P.; Bernasconi, F.; Dutly, F.; Schinzel, A.A.

    1996-01-11

    Twenty-four cases of trisomy 13 and one case with disomy 13, but a de novo dic(13,13)(p12p12) chromosome, were examined with molecular markers to determine the origin of the extra (or rearranged) chromosome. Twenty-one of 23 informative patients were consistent with a maternal origin of the extra chromosome. Lack of a third allele at any locus in both paternal origin cases indicate a somatic duplication of the paternal chromosome occurred. Five cases had translocation trisomy. The patient with a paternal rob(13q14q) had a maternal meiotic origin of the trisomy; thus, the paternal inheritance of the translocation chromosome was purely coincidental. Since there is not a significantly increased risk for unbalanced offspring of a t(13q14q) carrier and most trisomies are maternal in origin, this result should not be surprising; however, it illustrates that one cannot infer the origin of translocation trisomy based on parental origin of the translocation. Lack of a third allele at any locus in one of the three t(13q13q) cases indicates that it was most likely an isochromosome of postmeiotic origin, whereas the other two cases showed evidence of recombination. One balanced (nontrisomic) case with a nonmosaic 45, -13, -13, +t(13;13) karyotype was also investigated and was determined to be a somatic Robertsonian translocation between the maternal and paternal homologues, as has been found for all balanced homologous Robertsonian translocations so far investigated. Thus, it is also incorrect to assume in de novo translocation cases that the two involved chromosomes are even from the same parent. Despite a maternal origin of the trisomy, we cannot therefore infer anything about the parental origin of the chromosomes 13 and 14 involved in the translocation in the de novo t(13q14q) case nor for the two t(13;13) chromosomes showing a meiotic origin of the trisomy. 30 refs., 1 fig., 2 tabs.

  8. Survival of mountain quail translocated from two distinct source populations

    USGS Publications Warehouse

    Troy, Ronald J.; Coates, Peter S.; Connelly, John W.; Gillette, Gifford; Delehanty, David J.

    2013-01-01

    Translocation of mountain quail (Oreortyx pictus) to restore viable populations to their former range has become a common practice. Because differences in post-release vital rates between animals from multiple source populations has not been well studied, wildlife and land managers may arbitrarily choose the source population or base the source population on immediate availability when planning translocation projects. Similarly, an understanding of the optimal proportion of individuals from different age and sex classes for translocation would benefit translocation planning. During 2006 and 2007, we captured and translocated 125 mountain quail from 2 ecologically distinct areas: 38 from southern California and 87 from southwestern Oregon. We released mountain quail in the Bennett Hills of south-central Idaho. We radio-marked and monitored a subsample of 58 quail and used them for a 2-part survival analysis. Cumulative survival probability was 0.23 ± 0.05 (SE) at 150 days post-release. We first examined an a priori hypothesis (model) that survival varied between the 2 distinct source populations. We found that source population did not explain variation in survival. This result suggests that wildlife managers have flexibility in selecting source populations for mountain quail translocation efforts. In a post hoc examination, we pooled the quail across source populations and evaluated differences in survival probabilities between sex and age classes. The most parsimonious model indicated that adult male survival was substantially less than survival rates of other mountain quail age and sex classes (i.e., interaction between sex and age). This result suggests that translocation success could benefit by translocating yearling males rather than adult males, perhaps because adult male breeding behavior results in vulnerability to predators

  9. Segmentation of Unstructured Datasets

    NASA Technical Reports Server (NTRS)

    Bhat, Smitha

    1996-01-01

    Datasets generated by computer simulations and experiments in Computational Fluid Dynamics tend to be extremely large and complex. It is difficult to visualize these datasets using standard techniques like Volume Rendering and Ray Casting. Object Segmentation provides a technique to extract and quantify regions of interest within these massive datasets. This thesis explores basic algorithms to extract coherent amorphous regions from two-dimensional and three-dimensional scalar unstructured grids. The techniques are applied to datasets from Computational Fluid Dynamics and from Finite Element Analysis.

  10. Surface modification of graphene nanopores for protein translocation

    PubMed Central

    Shan, Y. P.; Tiwari, P. B.; Krishnakumar, P.; Vlassiouk, I.; Li, W.Z.; Wang, X.W.; Darici, Y.; Lindsay, S.M.; Wang, H. D.; Smirnov, S.; He, J.

    2014-01-01

    Studies of DNA translocation through graphene nanopores have revealed their potential for DNA sequencing. Here we report a study of protein translocation through chemically modified graphene nanopores. A transmission electron microscope (TEM) was used to cut nanopores with diameters between 5-20 nm in multilayer graphene prepared by chemical vapor deposition (CVD). After oxygen plasma treatment, the dependence of the measured ionic current on salt concentration and pH was consistent with a small surface charge induced by the formation of carboxyl groups. While translocation of gold nanoparticles (10 nm) was readily detected through such treated pores of a larger diameter, translocation of protein ferritin was not observed either for oxygen plasma treated pores, or for pores modified with mercaptohexadecanoic acid. Ferritin translocation events were reliably observed after the pores were modified with the phospholipid-PEG (DPPE-PEG750) amphiphile. The ion current signature of translocation events was complex, suggesting that a series of interactions between the protein and pore occur during the process. PMID:24231385

  11. Translocation of α-helix chains through a nanopore

    NASA Astrophysics Data System (ADS)

    Yang, Zhiyong; Li, Shiben; Zhang, Linxi; ur Rehman, Ateeq; Liang, Haojun

    2010-10-01

    The translocation of α-helix chains through a nanopore is studied through Langevin dynamics simulations. The α-helix chains exhibit several different characteristics about their average translocation times and the α-helix structures when they transport through the nanopores under the driving forces. First, the relationship between average translocation times τ and the chain length N satisfies the scaling law, τ ˜Nα, and the scaling exponent α depends on the driving force f for the small forces while it is close to the Flory exponent (ν) in the other force regions. For the chains with given chain lengths, it is observed that the dependence of the average translocation times can be expressed as τ ˜f-1/2 for the small forces while can be described as τ ˜f in the large force regions. Second, for the large driving force, the average number of α-helix structures Nh decreases first and then increases in the translocation process. The average waiting time of each bead, especially of the first bead, is also dependent on the driving forces. Furthermore, an elasticity spring model is presented to reasonably explain the change of the α-helix number during the translocation and its elasticity can be locally damaged by the large driving forces. Our results demonstrate the unique behaviors of α-helix chains transporting through the pores, which can enrich our insights into and knowledge on biopolymers transporting through membranes.

  12. Atomic structure of anthrax PA pore elucidates toxin translocation

    PubMed Central

    Jiang, Jiansen; Pentelute, Bradley L.; Collier, R. John; Zhou, Z. Hong

    2015-01-01

    Summary Anthrax toxin, comprising protective antigen (PA), lethal factor (LF) and edema factor (EF), is the major virulence factor of Bacillus anthracis, an agent that causes high mortality in human and animals. PA forms oligomeric prepores that undergo conversion to membrane-spanning pores by endosomal acidification, and these pores translocate the enzymes LF and EF into the cytosol of target cells1. PA is not only a vaccine component and therapeutic target for anthrax infections but also an excellent model system for understanding the mechanism of protein translocation. Based on biochemical and electrophysiological results, researchers have proposed that a Φ-clamp composed of Phe427 residues of PA catalyzes protein translocation via a charge-state dependent Brownian ratchet2–9. Although atomic structures of PA prepores are available10–14, how PA senses low pH, converts to active pore and translocates LF and EF are not well defined without an atomic model of the PA pore. Here, by cryo electron microscopy (cryoEM) with direct electron counting, we have determined the PA pore structure at 2.9-Å resolution. The structure reveals the long-sought-after catalytic Φ-clamp and the membrane-spanning translocation channel, and supports the Brownian ratchet model for protein translocation. Comparisons of four structures reveal conformational changes in prepore to pore conversion that support a multi-step mechanism by which low-pH is sensed and the membrane-spanning channel is formed. PMID:25778700

  13. Protein kinase C translocation in human blood platelets

    SciTech Connect

    Wang, Hoauyan; Friedman, E. )

    1990-01-01

    Protein kinase C (PKC) activity and translocation in response to the phorbol ester, phorbol 12-myristate, 13-acetate (PMA), serotonin (5-HT) and thrombin was assessed in human platelets. Stimulation with PMA and 5-HT for 10 minutes or thrombin for 1 minute elicited platelet PKC translocation from cytosol to membrane. The catecholamines, norepinephrine or epinephrine at 10 {mu}M concentrations did not induce redistribution of platelet PKC. Serotonin and the specific 5-HT{sub 2} receptor agonist, 1-(2,5-dimethoxy-4-iodophenyl)-2-amino-propane (DOI) but not the 5-HT{sub 1A} or 5-HT{sub 1B} agonists, ({plus minus}) 8-hydroxy-dipropylamino-tetralin (8-OH-DPAT) or 5-methoxy-3-3-(1,2,3,6-tetrahydro-4-pyridin) 1H-indole succinate (RU 24969) induced dose-dependent PKC translocations. Serotonin-evoked PKC translocation was blocked by selective 5-HT{sub 2} receptor antagonists, ketanserin and spiroperidol. These results suggest that, in human platelets, PMA, thrombin and 5-HT can elicit PKC translocation from cytosol to membrane. Serotonin-induced PKC translocation in platelets is mediated via 5-HT{sub 2} receptors.

  14. Atomic structure of anthrax protective antigen pore elucidates toxin translocation.

    PubMed

    Jiang, Jiansen; Pentelute, Bradley L; Collier, R John; Zhou, Z Hong

    2015-05-28

    Anthrax toxin, comprising protective antigen, lethal factor, and oedema factor, is the major virulence factor of Bacillus anthracis, an agent that causes high mortality in humans and animals. Protective antigen forms oligomeric prepores that undergo conversion to membrane-spanning pores by endosomal acidification, and these pores translocate the enzymes lethal factor and oedema factor into the cytosol of target cells. Protective antigen is not only a vaccine component and therapeutic target for anthrax infections but also an excellent model system for understanding the mechanism of protein translocation. On the basis of biochemical and electrophysiological results, researchers have proposed that a phi (Φ)-clamp composed of phenylalanine (Phe)427 residues of protective antigen catalyses protein translocation via a charge-state-dependent Brownian ratchet. Although atomic structures of protective antigen prepores are available, how protective antigen senses low pH, converts to active pore, and translocates lethal factor and oedema factor are not well defined without an atomic model of its pore. Here, by cryo-electron microscopy with direct electron counting, we determine the protective antigen pore structure at 2.9-Å resolution. The structure reveals the long-sought-after catalytic Φ-clamp and the membrane-spanning translocation channel, and supports the Brownian ratchet model for protein translocation. Comparisons of four structures reveal conformational changes in prepore to pore conversion that support a multi-step mechanism by which low pH is sensed and the membrane-spanning channel is formed. PMID:25778700

  15. Surface modification of graphene nanopores for protein translocation.

    PubMed

    Shan, Y P; Tiwari, P B; Krishnakumar, P; Vlassiouk, I; Li, W Z; Wang, X W; Darici, Y; Lindsay, S M; Wang, H D; Smirnov, S; He, J

    2013-12-13

    Studies of DNA translocation through graphene nanopores have revealed their potential for DNA sequencing. Here we report a study of protein translocation through chemically modified graphene nanopores. A transmission electron microscope (TEM) was used to cut nanopores with diameters between 5 and 20 nm in multilayer graphene prepared by chemical vapor deposition (CVD). After oxygen plasma treatment, the dependence of the measured ionic current on salt concentration and pH was consistent with a small surface charge induced by the formation of carboxyl groups. While translocation of gold nanoparticles (10 nm) was readily detected through such treated pores of a larger diameter, translocation of the protein ferritin was not observed either for oxygen plasma treated pores, or for pores modified with mercaptohexadecanoic acid. Ferritin translocation events were reliably observed after the pores were modified with the phospholipid-PEG (DPPE-PEG750) amphiphile. The ion current signature of translocation events was complex, suggesting that a series of interactions between the protein and pores occurs during the process. PMID:24231385

  16. Autonomous Rubidium Clock Weak Frequency Jump Detector for Onboard Navigation Satellite System.

    PubMed

    Khare, Akshay; Arora, Rajat; Banik, Alak; Mehta, Sanjay D

    2016-02-01

    Frequency jumps are common in rubidium frequency sources. They affect the estimation of user position in navigational satellite systems. These jumps must be detected and corrected immediately as they have direct impact on the navigation system integrity. A novel weak frequency jump detector is proposed based on a Kalman filter with a multi-interval approach. This detector can be applied for both "sudden" and "slow" frequency transitions. In this detection method, noises of clock data are reduced by Kalman filtering, for accurate estimation of jump size with less latency. Analysis on in-orbit rubidium atomic frequency standard (RAFS) phase telemetry data shows that the detector can be used for fast detection and correction of weak frequency jumps. Furthermore, performance comparison of different existing frequency jump detection techniques with the proposed detector is discussed. A multialgorithm-based strategy is proposed depending on the jump size and latency for onboard navigation satellites having RAFS as the primary frequency source. PMID:26685233

  17. Carbon translocation in zooanthaellae-coelenterate symbioses

    SciTech Connect

    Battey, J.F.

    1985-01-01

    When host and algal triglycerides synthesized in the symbiotic sea anemone Condylactis gigantea during light and dark incubations in /sup 14/C-bicarbonate and /sup 14/C-acetate were deacylated, more then 80% of the radioactivity was found in the fatty acid moiety. In contrast, triglycerides isolated from zooxanthellae and host incubated in /sup 14/C-glycerol in the dark were found to have more then 95% of their radioactivity in the glycerol moiety. During /sup 14/C-glycerol incubations in the light, radioactivity in the fatty acid moiety of zooxanthellae triglyceride fatty acid moiety stayed below 5% during /sup 14/C-glycerol incubations in the light. These results show neither the zooxanthellae nor host can rapidly convert glycerol to fatty acid. Radioactivity from /sup 14/C-glycerol that does eventually appear in host lipid may have been respired to /sup 14/CO/sub 2/ then photosynthetically fixed by the zooxanthellae and synthesized into lipid fatty acid. The isolated zooxanthellae of C. gigantea contained 3.62 +/- 0.33 mM glycerol, which was 26x the 0.141 +/- 0.02 mM found in the coelenterate tissue. Aposymbiotic coelenterate tissue contained 0.169 +/- 0.05 mM glycerol. The metabolic inhibitors, sodium cyanide, aminooxyacetic acid and cerulenin were used to try and uncouple the production of glycerol by the zooxanthellae from its utilization by the coelenterate host. 10/sup -5/ M NaCN increased the ratio of cross photosynthesis to respiration in both intact tentacles and isolated zooxanthellae, increased translocation from 17.7 +/- 3.5% of total fixed carbon in controls to 43.5 +/- 5.79%, and doubled the amount of photosynthetically fixed carbon accumulating in the coelenterate host over that in controls.

  18. Using survival analysis to study translocation success in the Gila topminnow (Poeciliopsis occidentalis).

    PubMed

    Sheller, Frances J; Fagan, William F; Unmack, Peter J

    2006-10-01

    Translocation, the intentional release of captive-propagated and/or wild-caught animals into the wild in an attempt to establish, reestablish, or augment a population, is a commonly used approach to species conservation. Despite the frequent mention of translocation as an aid in threatened or endangered species recovery plans, translocations have resulted in the establishment of few sustainable populations. To improve the effectiveness of translocation efforts, it is essential to identify and adopt features that contribute to successful translocations. This study analyzed 148 translocations of the endangered Gila topminnow (Poeciliopsis occidentalis) to identify various factors that have significantly influenced translocation success. We quantified success as the "persistence time" of translocated populations and used survival analysis to interpret the role of several factors. The following factors affected persistence times of translocated populations: season in which the fish were translocated, habitat type of the translocation site, and genetic origin of the fish stocked. In general, factors associated with stocking, the population stocked, and the site of translocation can significantly affect the persistence of translocated populations and thus increase the probability of translocation success. For Gila topminnow, future translocations should be undertaken in late summer or fall (not early summer), should occur into ponds (not streams, wells, or tanks), and should generally utilize individuals from genetic lineages other than Monkey Spring. For other species, a key lesson emerging from this work is that life history attributes for each translocated species need to be considered carefully. PMID:17069370

  19. Analysis of the V(D)J recombination efficiency at lymphoid chromosomal translocation breakpoints.

    PubMed

    Raghavan, S C; Kirsch, I R; Lieber, M R

    2001-08-01

    Chromosomal translocations and deletions are among the major events that initiate neoplasia. For lymphoid chromosomal translocations, misrecognition by the RAG (recombination activating gene) complex of V(D)J recombination is one contributing factor that has long been proposed. The chromosomal translocations involving LMO2 (t(11;14)(p13;q11)), Ttg-1 (t(11;14)(p15;q11)), and Hox11 (t(10;14)(q24;q11)) are among the clearest examples in which it appears that a D or J segment has synapsed with an adventitious heptamer/nonamer at a gene outside of one of the antigen receptor loci. The interstitial deletion at 1p32 involving SIL (SCL-interrupting locus)/SCL (stem cell leukemia) is a case involving two non-V(D)J sites that have been suggested to be V(D)J recombination mistakes. Here we have used our human extrachromosomal substrate assay to formally test the hypothesis that these regions are V(D)J recombination misrecognition sites and, more importantly, to quantify their efficiency as V(D)J recombination targets within the cell. We find that the LMO2 fragile site functions as a 12-signal at an efficiency that is only 27-fold lower than that of a consensus 12-signal. The Ttg-1 site functions as a 23-signal at an efficiency 530-fold lower than that of a consensus 23-signal. Hox11 failed to undergo recombination as a 12- or 23-signal and was at least 20,000-fold less efficient than consensus signals. SIL has been predicted to function as a 12-signal and SCL as a 23-signal. However, we find that SIL actually functions as a 23-signal. These results provide a formal demonstration that certain chromosomal fragile sites can serve as RAG complex targets, and they determine whether these sites function as 12- versus 23-signals. These results quantify one of the three major factors that determine the frequency of these translocations in T-cell acute lymphocytic leukemia. PMID:11390401

  20. Segmented Target Design

    NASA Astrophysics Data System (ADS)

    Merhi, Abdul Rahman; Frank, Nathan; Gueye, Paul; Thoennessen, Michael; MoNA Collaboration

    2013-10-01

    A proposed segmented target would improve decay energy measurements of neutron-unbound nuclei. Experiments like this have been performed at the National Superconducting Cyclotron Laboratory (NSCL) located at Michigan State University. Many different nuclei are produced in such experiments, some of which immediately decay into a charged particle and neutron. The charged particles are bent by a large magnet and measured by a suite of charged particle detectors. The neutrons are measured by the Modular Neutron Array (MoNA) and Large Multi-Institutional Scintillation Array (LISA). With the current target setup, a nucleus in a neutron-unbound state is produced with a radioactive beam impinged upon a beryllium target. The resolution of these measurements is very dependent on the target thickness since the nuclear interaction point is unknown. In a segmented target using alternating layers of silicon detectors and Be-targets, the Be-target in which the nuclear reaction takes place would be determined. Thus the experimental resolution would improve. This poster will describe the improvement over the current target along with the status of the design. Work supported by Augustana College and the National Science Foundation grant #0969173.