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A delicate balance exists between life and death in ecosystems, species, individuals and even neurons. A neuron can suffer a barrage of insults, and still protective factors may allow the cell to endure. However, once a critical threshold of damage is reached, the cell cannot recover. This balance of positive and negative influences affects not only the lifespan of a single neuron but can ultimately shape the lifespan of the organism itself. In order to understand the causes of accelerated and normal neurological aging in mammals, we studied two "normal aging" control strains and two senescence-accelerated mouse strains, SAMP8/Ta (S8) and SAMP10//Ta (S10), which exhibit an early onset of age- related behavioral and neuropathological phenotypes. Hippocampal gene expression analyses revealed only a few common gene expression changes with age in all four lines. The accelerated aging lines exhibited fewer upregulated genes with age, especially S8, and throughout their life showed higher expression of repetitive viral sequences and lower levels of important transcription factors. Specifically, the S8 strain demonstrated upregulation of several inflammatory genes, which may indicate elevated oxidative stress, whereas the S10 line showed increased levels of caspase 9, suggesting a higher basal level of cell death. In an attempt to detect sequence differences present within the gene expression data, we developed a web-based tool, GeSNP, that identified several genes containing mutations in the aging accelerated strains. Importantly, the S10 strain contains a splicing mutation in the mRNA of fibroblast growth factor 1 (Fgf1) that results in a C-terminal truncation eliminating most of the heparin-binding domain. Several truncated forms of Fgfs have been previously shown to act as antagonists. In order to determine if the mutant Fgf1 interferes with the effects of other co-expressed Fgfs in a dominant negative manner, we transiently transfected Fgf2 and the S10 mutant Fgf1 int

This paper describes the design and implementation of the grounding and shielding system for the ATLAS SemiConductor Tracker (SCT). The mitigation of electromagnetic interference and noise pickup through power lines is the critical design goal as they have the potential to jeopardize the electrical performance. We accomplish this by adhering to the ATLAS grounding rules, by avoiding ground loops and isolating the different subdetectors. Noise sources are identified and design rules to protect the SCT against them are described. A rigorous implementation of the design was crucial to achieve the required performance. This paper highlights the location, connection and assembly of the different components that affect the grounding and shielding system: cables, filters, cooling pipes, shielding enclosure, power supplies and others. Special care is taken with the electrical properties of materials and joints. The monitoring of the grounding system during the installation period is also discussed. Finally, after connecting more than four thousand SCT modules to all of their services, electrical, mechanical and thermal within the wider ATLAS experimental environment, dedicated tests show that noise pickup is minimised.

Minimum norm quadratic unbiased estimation, or MINQUE, is a method for improving the variance estimates of noise components in a Gauss-Markov least-squares problem. This study treats a simple special case: estimating the two noise levels of a clock whose phase noise is the sum of white FM and random walk FM. Given prior estimates of the noise levels, perhaps from an Allan deviation plot, MINQUE calculates new estimates and their uncertainties. Although the original MINQUE calculation on N data takes O(N2) space and O(N3) time, it can be done sequentially in bounded space and O(N) time. The method is applied to data from a simulation and from a comparison of two hydrogen masers., See also ADM002186. Presented at the Annual Precise Time and Time Interval (PTTI) Systems and Appliations Meeting (40th) held in Reston, Virginia on 1-4 December 2008. Published in the Proceedings of the Annual Precise Time and Time Interval (PTTI) Systems and Appliations Meeting (40th), p275-286, 2008. The original document contains color images.

We show how to solve two problems of optimal linear estimation from a finite set of phase data. Clock noise is modeled as a stochastic process with stationary dth increments. The covariance properties of such a process are contained in the generalized autocovariance function (GACV). We set up two principles for optimal estimation; these principles lead to a set of linear equations for the regression coefficients and some auxiliary parameters. The mean square errors of the estimators are easily calculated. The method can be used to check the results of other methods and to find good suboptimal estimators based on a small subset of the available data., Presented at the Joint IEEE International Frequency Symposium and Precise Time and Time Interval (PTTI) Systems and Applications Meeting, held in Vancouver, BC, Canada on 29-31 Aug 2005.

This work gives an algorithm for computing the degrees of freedom of estimators of Allan and Hadamard variances, including their modified versions. A consistent approach is used throughout., See also ADM001690, Proceedings of the Annual Precise Time and Time Interval (PTTI) Meeting (35th), held in San Diego, CA, 2-4 Dec 2003, p267-280. Prepared in cooperation with Symmetricom, Inc., San Jose, CA. The original document contains color images.

NPL has developed a Kalman-filter-based clock algorithm for combining measurements from its three active hydrogen masers. The algorithm is designed to produce a near optimal composite when the dominant noise process present is flicker frequency modulation (FFM). The FFM is modelled approximately by a linear combination of Markov noise processes. Each Markov process is included in the Kalman filter and contributes an additional component to its state vector. Both the validity of the model and the effectiveness of adding these additional components to the state vector are examined. The performance of the new algorithm is examined when applied to simulated measurements and also to measurements obtained from NPL's hydrogen masers., See also ADM001690. Presented at Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting (35th) held in San Diego, CA, on 2-4 Dec 2003. The original document contains color images.

A composite clock created from a local clock ensemble is known by its time offsets from the ensemble clocks. By a geometrical argument, estimates for the instability of the composite clock are calculated from the instabilities of the ensemble clocks, individually and against the composite clock. The method is illustrated by examples using simulated and real ensembles., See also ADM001784. Presented at Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting, held in Washington, DC on 7-9 Dec 2004. The original document contains color images.

Four algorithms for simulating flicker FM phase noise (f(-3) spectrum) are given, two old and two new. Their Allan deviation and mean square time interval error (MSTIE) are examined. The MSTIE shows that one of the old algorithms has deficient long-term phase deviations on average. The Allan deviation does not reveal this deficiency., See also ADM001507. Presented at the Annual Precise Time and Time Interval (PTTI) Planning Meeting (34th), held in Reston, VA, on 3-5 December 2002. Published in the proceedings of the meeting, p481-492, 2003.

A stability analyzer is being developed for frequency standards in JPL's Deep Space Network. Prototype hardware and software have been built. Initial tests on 100-MHz sources show an Allan deviation noise floor of about 7 x 10-15 at 1 second for a dual-mixer channel., See also ADM001482. Presented at the Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting (33rd), held in Long Beach, CA, on 27-29 Nov 2001. Published in the proceedings of the meeting, p377-384, 2002.

KPW is a time scale algorithm that combines Kalman filtering with the basic time scale equation (BTSE). A single Kalman filter that estimates all clocks simultaneously is used to generate the BTSE frequency estimates, while the BTSE weights are inversely proportional to the white FM variances of the clocks. Results from simulated clock ensembles are compared to previous simulation results from other algorithms., See also ADM001482. Presented at the Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting (33rd), held in Long Beach, CA, on 27-29 Nov 2001. Published in the proceedings of the meeting, p445-454, 2001.

We describe a method based on the Total deviation approach whereby we improve the confidence of the estimation of the Hadamard deviation that is used primarily in GPS operations. The Hadamard-total deviation described in this paper provides a significant improvement in confidence indicated by an increase of 1.3 to 3.4 times the one degree of freedom of the plain Uadamard deviation at the longest averaging time. The new Hadamard-total deviation is slightly negativdy biased with respect to the usual Uadamard deviation, and T values are restricted to less than or equal to T/3, to be consistent with the usual Uadamard's definition. We give a method of automatically removing bias by a power-law detection scheme. We review the relationship between Kalman fiber parameters and the Hadamard and Allan variances, illustrate the operational problems associated with estimating these parameters, and discuss how the Uadamard-total variance can improve management of present and future GPS satellite clocks., See also ADM001509. Presented at the Annual Precise Time and Time Interval (PTTI), Meeting (32nd), held in Reston, VA on 28-30 Nov 2000. Published in the Proceedings of the Annual Precise Time and Time Interval (PTTI), Nov 2000.

We give results of recent work on a newly developed frequency stability characterization, called Total variance, whose main advantages are improved confidence at and near the longest averaging time of half the data duration, and lower sensitivity to drift removal. Properties given here, for the standard FM noise types, include mean, degrees of freedom, frequency response, and empircal distribution function., See also ADA418244. Presented at the Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting (29th) held in Long Beach, CA on 2-4 Dec 1997. Published in the Annual Precise Time and Time Interval Systems and Applications Meeting Proceedings, p39-48, Dec 1997.

An approximating algorithm for computing equivalent degrees of freedom of the modified Allan variance and its square root, the modified Allan deviation (MVAR and MDEV), and the time variance and time deviation (TVAR and TDEV) is presented, along with an algorithm for approximating the inverse chi-squared distribution. These two algorithms allow relatively simple computations of confidence intervals on MDEV and TDEV, the latter currently used as a standard in the telecommunications industry. These algorithms enable users to present variance with confidence intervals corresponding to any useful probability for most data lengths and noise types., See also ADA419480. Presented at the Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting (28th) held in Reston, VA on 3-5 Dec 1996. Published in the Annual Precise Time and Time Interval Applications and Planning Meeting Proceeddings, p215-224, Dec 1996.

The phase of a frequency standard that uses periodic interrogation and control of a local oscillator (LO) is degraded by a long-term random-- component induced down-conversion of LO noise into the loop passband. The Dick formula for the noise level of this degradation can be derived from explicit solutions of two LO control-loop models. A summary of the derivations is given here., See also ADA419480. Presented at the Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting (28th) held in Reston, VA on 3-5 Dec 1996. Published in the Annual Precise Time and Time Interval Applications and Planning Meeting Proceedings, p265-272, Dec 1996.

A stability analyzer for testing NASA Deep Space Network installations during flight radio science experiments is described. The stability analyzer provides realtime measurements of signal properties of general experimental interest: power, phase, and amplitude spectra; Allan deviation; and time series of amplitude, phase shift, and differential phase shift. Input ports are provided for up to four 100 MHz frequency standards and eight baseband analog (>100 kHz bandwidth) signals. Test results indicate the following upper bounds to noise floors when operating on 100 MHz signals: -145 dBc/Hz for phase noise spectrum further than 200 Hz from carrier, 2.5 x 10(-15) (tau =1 second) and 1.5 x 10(-17) (Tau = 1000 seconds) for Allan deviation, and 1 x 10(-4) degrees for 1-second averages of phase deviation. Four copies of the stability analyzer have been produced, plus one transportable unit for use at non-NASA observatories., Presented at the Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting (26th) held in Reston, VA on 6-8 Dec 1994. Published in the Annual Precise Time and Time Interval Applications and Planning Meeting Proceedings, p221-234, Dec 1994.

The objective of this project was to further develop the techniques associated with the preparation of samples of substituted perfluoropolyethers, including the preparation of a 10 to 20 gram sample of perfluoropolyether for lubricant testing by the USAF.

Perfluorinated polyethers are an important component of the long-term strategy of the USAF, as high-temperature lubricants. Current, commercially-available materials are exemplified by the 'KRYTOX' (1) (DuPont), 'FOMBLIN' (2) (Montefluos), and 'DEMNUM' (3) (Daikin) fluids. All of these products involve a polymerisation, of a fluorinated precursor, which can be difficult to control. In particular, it is difficult to obtain high molecular weight material.

As the performance of passive atomic frequency standards improves, a new limitation is encountered due to frequency fluctuations in an ancillary local oscillator (L.O.). The effect is due to time variation in the gain of the feedback which compensates L.O. frequency fluctuations. The high performance promised by new microwave and optical trapped ion standard may be severely compromised by this effect. We present un anabsk of this performance limitation for the case of sequentially interrogated standards. The time dependence of the sensitivity of the interrogation process to L.O. frequency fluctuations is evaluated for single-pulse and double-puke "Ramsey" RF interrogation and also for amplitude modulated pulses., See also ADA239372. Presented at the Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting (22nd) Held in Vienna, VA on 4-6 Dec 1990.

In Latin America, paralytic rabies transmitted by vampire bats is a major cause of death in cattle. This problem becomes more acute as countries attempt to increase livestock production to feed rapidly expanding human populations. Vaccination has been the principal weapon against rabies, however this offers no protection to domestic animals and poultry against dally predation of vampire bats. Established methods of vampire bat control, though limited, have proved effective and should be continued while more effective methods are being developed and tested. Existing methods are discussed in some detail. Of the approximately 200 kinds of bats found in Latin America all could be potential vectors of rabies. The 12 species most frequently found infected with rabies (including the three types of vampires) should receive close ecological study for possible control. They have certain attributes in common: they have been reported rabid; are found in association with vampires; are widely distributed; are found in buildings near domestic animals and people; live in groups; have sharp teeth; fly considerable distances; frequently change their roosts; do not hibernate and are biologically or economically Important. Improved vampire bat control must be based on an ecological approach in which all available techniques are combined into an integrated control which will not affect other species of bats. Such an approach could use biological, chemical, physical, and regulatory techniques. These cannot be fully developed until basic information Is available on two points. First, there must be a thorough understanding of the ecosystem in which the bats live, including population dynamics. Second, the population levels which cause damage must be determined. This information is lacking for vampire bats. Two other questions must also be answered: first, what are the host preferences of vampire bats throughout their range from Mexico to Argentina? And second, how many vampires inhabit any

This review of the public health importance and control of bats is oriented to Trinidad, since this country is well known for its studies of bat problems, especially rabies, and its bat control program. Bat problems which require control are: bat-associated diseases (viral, spirochetal, fungal, bacterial, and protozoan), vampire bats, and house bats. Present methods of bat control and possibilities for future control are discussed, as this is a matter of importance to Trinidad and other countries in Central and South America. Because of its large variety of bats and location, the small island of Trinidad is a natural laboratory to study bat ecology and evaluate control measures. A list of pertinent references is provided.

Field notes on various insects from Greenhall's trips to Cuba, Panama, Jamaica and Costa Rica in 1932., http://name.umdl.umich.edu/IC-INSECT1IC-X-68%5DUMMZI-FN065_006, http://quod.lib.umich.edu/cgi/i/image/api/thumb/insect1ic/68/UMMZI-FN065_006/!250,250, The University of Michigan Library provides access to these materials for educational and research purposes. These materials may be under copyright. If you decide to use any of these materials, you are responsible for making your own legal assessment and securing any necessary permission. If you have questions about the collection, contact the Collections Manager: insect-dlps-help@umich.edu. If you have concerns about the inclusion of an item in this collection, please contact Library Information Technology: libraryit-info@umich.edu., http://quod.lib.umich.edu/t/text/accesspolicy.html

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This work is concerned with estimating the upper envelopes S* of the absolute values of the partial sums of rearranged trigonometric sums. A.M. Garsia [Annals of Math. 79 (1964), 634-9] gave an estimate for the L2 norms of the S*, averaged over all rearrangements of the original (finite) sum. This estimate enabled him to prove that the Fourier series of any function in L2 can be rearranged so that it converges a.e. The main result of this thesis is a similar estimate of the Lq norms of the S*, for all even integers q. This holds for finite linear combinations of functions which satisfy a condition which is a generalization of orthonormality in the L2 case. This estimate for finite sums is extended to Fourier series of Lq functions; it is shown that there are functions to which the Men’shov-Paley Theorem does not apply, but whose Fourier series can nevertheless be rearranged so that the S* of the rearranged series is in Lq.

http://name.umdl.umich.edu/IC-MOLLUSK1IC-X-055462%5DUMMZ-MOL-55435-55471, https://quod.lib.umich.edu/cgi/i/image/api/thumb/mollusk1ic/055462/UMMZ-MOL-55435-55471/!250,250, The University of Michigan Library provides access to these materials for educational and research purposes. These materials may be under copyright. If you decide to use any of these materials, you are responsible for making your own legal assessment and securing any necessary permission. If you have questions about the collection, contact the UMMZ Mollusks Division professional staff: mollusk1ic-dlps-help@umich.edu. If you have concerns about the inclusion of an item in this collection, please contact Library Information Technology: libraryit-info@umich.edu.

http://name.umdl.umich.edu/IC-MOLLUSK1IC-X-055461%5DUMMZ-MOL-55435-55471, https://quod.lib.umich.edu/cgi/i/image/api/thumb/mollusk1ic/055461/UMMZ-MOL-55435-55471/!250,250, The University of Michigan Library provides access to these materials for educational and research purposes. These materials may be under copyright. If you decide to use any of these materials, you are responsible for making your own legal assessment and securing any necessary permission. If you have questions about the collection, contact the UMMZ Mollusks Division professional staff: mollusk1ic-dlps-help@umich.edu. If you have concerns about the inclusion of an item in this collection, please contact Library Information Technology: libraryit-info@umich.edu.

A simple model of the m-cornered hat estimation problem is set up and solved by the method of maximum likelihood. The method is compared by simulation to a least squares method of Barnes and is shown to be inferior to it on the basis of mean square error. A bootstrap method of computing estimator performance is presented., Presented at the Proceedings of the Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting (19th) held in Redondo Beach, CA on 1-3 Dec 1987. Published in the Proceedings of the Annual Precise Time and Time Interval Applications and Planning Meeting Conference, p219-226, Dec 1987.

Tests of the effect of various environmental parameters on HP 5061B, option 004, cesium beam frequency standards have been made at the test facilities of the Frequency Standards Laboratory at JPL. These standards were on loan from the United States Naval Observatory for these tests as a part of a larger cooperative program of testing and adjustment of cesium beam frequency standards between the United States Naval Observatory, National Institute of Standards and Technology, Jet Propulsion Laboratory and the University of Ancona. The environmental parameters of interest, include humidity, ambient pressure and temperature. Marked sensitivity to humidity was found in all the standards, but the sign of frequency change vs relative humidity was not the same in all standards. The results of all the tests will be given and plans for future work under this program will be discussed., See also ADA224769. Published in the Proceedings of the Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting (21st) Held in Redondo Beach, CA on 28-30 Nov 1989.

The computer simulation of complex systems often requires efficient recursive algorithms to generate various noise types. Flicker noise often occurs in frequency and time systems and long samples (a million or more lags) are needed. In June of 1971 two papers on flicker noise simulation were published independently. Barnes and Jarvis based the simulation on the sum of several low pass filtered white, Gaussian noises. He showed that the noise level and the filter passband of each noise can be selected to provide an approximate flicker noise over a finite but arbitrary spectral range. The precision of fit to the flicker spectrum can be arbitrarily good depending on the number of independent elements used. Barnes and Jarvis based their simulation on a cascade of lead-lag filters. Similarly, the extent and goodness of fit of the output noise depends only on the number of filter stages used. The Barnes-Jarvis procedure has an exact inverse which has advantages over the Mandelbrot method in some statistical applications other than noise simulation. The Barnes-Jarvis method can be expressed as an ARIMA model, but certain problems arise from the loss of significant digits. The significant digits problem can be avoided by using the ARIMA model in "factored form". Flicker noise is a noise whose power spectral density (PSD) varies approximately as the reciprocal of the Fourier frequency over a large, but finite range., Pub. in the Proceedings of the Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting (19th) Held 1-3 Dec 1987 in Redondo Beach, CA.

Continuous-time models of oscillator phase noise x(t) usually have stationary nth differences, for some n. The purpose of this paper is to demonstrate an easy way to computing a class of time-domain oscillator stability measures known collectively as the Structure Function., Presented at the Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting (14th), held in Greenbelt, Maryland on 30 November-2 December 1982 and published in proceedings of the same, p281-294, 1982.

Vampire bat rabies is one of the greatest deterrants to the raising of livestock in Latin America. To know more of the epizootiology of the disease as well as to understand the ecology of the vampire bat family, Desmodontidae, detailed information about their feeding habits and host preferences is essential. Vampire bats feed exclusively on blood. Examination of probable host animals for bat bites has been the primary method used to determine their victims. More reliable precise data are achieved by serological analyses of the digestive tract contents of vampires killed after attacking their hosts. Precipitin test techniques were used similar to those devised for the identification of blood meals of bloodsucking arthropods (Weitz, 1952, 1956, 1960; Tempelis & Lofy, 1963). If the exact domestic as well as wild animal host preferences of vampire bats were known, this knowledge could assist in their control and might indicate other hitherto unsuspected hosts.

Though usually beneficial, bats sometimes are a nuisance to humans (Greenhall & Stell, 1960), or may even constitute serious economic problems and health hazards. Most important in this respect are the vampire bats, especially of the genus Desmodus, which are abundant from northern Argentina through the whole of Latin America to the north of Mexico. The agricultural problem is caused on the one hand by weakening of the cattle through loss of blood, making them more susceptible to diseases and parasite infestation, as well as by transmitting paralytic rabies (Derriengue). An organized control of vampires has only been established in Trinidad (Greenhall, 1958). On the American continent some control efforts were undertaken sporadically by local veterinarians and cattle owners. They comprise mainly dynamiting or fumigating caves or burning hollow trees. As the controllers usually cannot distinguish between a vampire bat and another bat, they destroy more benefical bats than vampires and do more harm than good.

Item donated by the Upper Mississippi River Conservation Committee (UMRCC) to Murphy Library in 2018. Part of the UMRCC Collection housed at Murphy Library, University of Wisconsin-La Crosse.