ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Temporal and spatial variation in reproduction in the facultatively polygynous antMyrmica tahoensis (Hymenoptera: Formicidae) (1996)
    Springer
    Insectes sociaux 43 (1996), S. 309-317 
    Details
    ISSN: 1420-9098
    Keywords: Myrmica tahoensis ; sex ratio ; relatedness ; microsatellite DNA ; sex allocation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sex allocation was measured across six seasons in colonies of the facultatively polygynous antMyrmica tahoensis. The overall proportion of colonies that produced sexuals was constant throughout the study, but population-level sex ratios varied considerably. In 1991, 1993, and 1995, a significantly greater proportion of colonies produced females than in 1990, 1992, and 1994. Sex ratios were similar across six sites within individual years, suggesting a population-wide cause of sex-ratio variation. Individual colonies tended, on average, to produce similar sex ratios in consecutive years. Within-colony genetic relatedness, while strongly correlated with sex ratios within years, did not explain the year-to-year variation. It is suggested that extrinsic factors can limit the production of female sexuals, even when genetic relatedness is high enough to favor female production.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01242932
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    A Meissl-modified Vaníček and Kleusberg kernel to reduce the truncation error in gravimetric geoid computations (1998)
    Springer
    Journal of geodesy 72 (1998), S. 154-160 
    Details
    ISSN: 1432-1394
    Keywords: Key words. Gravimetric geoid determination ; Modified kernels ; Truncation error reduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract. A deterministic modification of Stokes's integration kernel is presented which reduces the truncation error when regional gravity data are used in conjunction with a global geopotential model to compute a gravimetric geoid. The modification makes use of a combination of two existing modifications from Vaníček and Kleusberg and Meissl. The former modification applies a root mean square minimisation to the upper bound of the truncation error, whilst the latter causes the Fourier series expansion of the truncation error to coverage to zero more rapidly by setting the kernel to zero at the truncation radius. Green's second identity is used to demonstrate that the truncation error converges to zero faster when a Meissl-type modification is made to the Vaníček and Kleusberg kernel. A special case of this modification is proposed by choosing the degree of modification and integration cap-size such that the Vaníček and Kleusberg kernel passes through zero at the truncation radius.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001900050157
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Analytical solutions to the multicylinder somatic shunt cable model for passive neurones with differing dendritic electrical parameters (1994)
    Springer
    Biological cybernetics 71 (1994), S. 547-557 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract The multicylinder somatic shunt cable model for passive neurones with differing time constants in each cylinder is considered in this paper. The solution to the model with general inputs is developed, and the parametric dependence of the voltage response is investigated. The method of analysis is straightforward and follows that laid out in Evans et al. (1992, 1994): (i) The dimensional problem is stated with general boundary and initial conditions, (ii) The model is fully non-dimensionalised, and a dimensionless parameter family which uniquely governs the behaviour of the dimensionless voltage response is obtained, (iii) The fundamental unit impulse problem is solved, and the solutions to problems involving general inputs are written in terms of the unit impulse solution, (iv) The large and small time behaviour of the unit impulse solution is examined, (v) The parametric dependence of the unit impulse upon the dimensionless parameter family is explored for two limits of practical interest. A simple expression for the principle relationship between the dimensionless parameter family is derived and provides insight into the interaction between soma and cylinders. A well-posed method for the solution of the dimensional inverse problem is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00198473
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Analytical solutions to the multicylinder somatic shunt cable model for passive neurones with differing dendritic electrical parameters (1994)
    Springer
    Biological cybernetics 71 (1994), S. 547-557 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract.  The multicylinder somatic shunt cable model for passive neurones with differing time constants in each cylinder is considered in this paper. The solution to the model with general inputs is developed, and the parametric dependence of the voltage response is investigated. The method of analysis is straightforward and follows that laid out in Evans et al. (1992, 1994): (i) The dimensional problem is stated with general boundary and initial conditions. (ii) The model is fully non-dimensionalised, and a dimensionless parameter family which uniquely governs the behaviour of the dimensionless voltage response is obtained. (iii) The fundamental unit impulse problem is solved, and the solutions to problems involving general inputs are written in terms of the unit impulse solution. (iv) The large and small time behaviour of the unit impulse solution is examined. (v) The parametric dependence of the unit impulse upon the dimensionless parameter family is explored for two limits of practical interest. A simple expression for the principle relationship between the dimensionless parameter family is derived and provides insight into the interaction between soma and cylinders. A well-posed method for the solution of the dimensional inverse problem is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004220050114
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    [ohne Titel] (2002)
    Oxford, UK : Blackwell Publishers, Inc.,
    Mathematical finance 12 (2002), S. 0 
    Details
    ISSN: 1467-9965
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mathematics , Economics
    Notes: Explicit expressions valid near expiry are derived for the values and the optimal exercise boundaries of American put and call options on assets with dividends. The results depend sensitively on the ratio of the dividend yield rate D to the interest rate r. For D〉r the put boundary near expiry tends parabolically to the value rK/D where K is the strike price, while for D≤r the boundary tends to K in the parabolic-logarithmic form found for the case D=0 by Barles et al. (1995) and by Kuske and Keller (1998). For the call, these two behaviors are interchanged: parabolic and tending to rK/D for D〈r, as was shown by Wilmott, Dewynne, and Howison (1993), and parabolic-logarithmic and tending to K for D≥r. The results are derived twice: once by solving an integral equation, and again by constructing matched asymptotic expansions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/1467-9965.02008
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Experimental study of implantation-induced disordering in InGaAsP strained multiple-quantum-well heterostructures (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 65 (1994), S. 1239-1241 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effect of strain on F+ and Si+ implantation-induced compositional disordering in InGaAsP strained layer multiple-quantum-well (MQW) heterostructures has been studied by investigating the temperature dependence of the photoluminescence (PL) spectra and spatial distribution of degree of polarization of PL for both compressive and tensile strained, and unstrained MQW heterostructures. It was found that under similar implantation and anneal conditions a spectral blueshift occurs which is largest in the compressively strained structure and the smallest in the tensile one. This behavior is explained in terms of implantation-enhanced interdiffusion, by taking into account the composition differences of elements between the wells and barriers. The development of strain related to the process of interdiffusion has been experimentally observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.112082
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Properties of dc helicity injected tokamak plasmas (1990)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 2 (1990), S. 1415-1420 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Several dc helicity injection experiments using an electron beam technique have been conducted on the Current Drive Experiment (CDX) [Phys. Rev. Lett. 59, 2165 (1987)] and the Continuous Current Tokamak (CCT) [Phys. Rev. Lett. 63, 2365 (1989)]. The data strongly suggest that tokamak plasmas are being formed and maintained by this method. The largest currents driven to date are 1 kA in CDX (qa =5) and 6 kA in CCT (qa =3.5). An initial comparison of discharge properties with helicity theory indicates rough agreement. Current drive energy efficiencies are 9% and 23% of Ohmic efficiency in two cases analyzed. Strong radial electric fields are observed in these plasmas that cause poloidal rotation and, possibly, improved confinement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859573
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Observation of separate electron and hole escape rates in unbiased strained InGaAsP multiple quantum well laser structures (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 2525-2527 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on the first time-resolved photoconductivity measurements in strained InGaAsP multiple quantum well 1.3 μm laser structures. The photoconductive response is characterized by two exponential time constants, a fast time constant of less than 500 ps and a long time constant between 10 and 20 ns. We attribute these to the escape of electrons and holes from the wells, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.109310
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Temperature dependence of the threshold current in gain-coupled distributed feedback lasers with periodically etched quantum wells: Mechanism for an appearance of infinite T0 (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 1892-1894 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A phenomenological model describing the temperature dependence of the threshold current of 1.3 μm gain-coupled distributed feedback (DFB) lasers with periodically etched strained-layer quantum wells is presented and compared to experimental results. The model can predict the minimum threshold current as a function of temperature (infinite T0), which has been observed experimentally. The mechanism for the appearance of this minimum is explained by the decrease of the detuning of the DFB-mode wavelength from the material gain-peak wavelength as the temperature increases. The condition for single-mode operation is also discussed with use of the effective gain of DFB laser structures. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.116285
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Maximum output power and maximum operating temperature of quantum well lasers (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 2871-2873 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An efficient phenomenological model describing the temperature dependence of the output power of multiquantum well (MQW) lasers is presented. The model can predict all the general features of the experimental results. The effect of series resistance, thermal resistance, cavity length, leakage current, and facet reflectivity on the maximum achievable power are analyzed in a systematic manner. The calculated maximum operating temperature (Tm), defined as the heat sink temperature at which the saturated output power vanishes due to heating, is in reasonable agreement with reported experimental results. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.120201
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...