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Received: 2016-05-24 | Accepted: 2016-07-28 | Available online: 2017-06-20 http://dx.doi.org/10.15414/afz.2017.20.01.23-27 The aim of this study was to determine the population structure and to perform genome-wide scan of footprints of natural selection in cattle using principal component analysis. The applied statistics to identify the SNPs associated with selection pressure focused mainly on the extreme values of F ST index. In our study the alternative individual-based approach adopted in the PCAdapt R package has been used. This approach is based on the assumption that markers extremely related to the population structure are also candidates for local adaptation of the population. The genotype data of 350 animals originating from four historically or geographically connected populations (Austrian Pinzgau, Slovak Pinzgau, Brown Swiss, Tyrol Grey) have been used to test this approach in cattle. As expected based on breed's origin the principal component analysis showed the division of animals in to the 3 separate clusters and the eigenvalues suggested to use of K=3 as optimal number. The analysis of genomic regions harbouring signals revealed the candidate genes previously associated with muscle formation and immunity system. Detecting signals of adaptation that were also the targets of historical selection will allow in the future a better understanding of cattle origin. Keywords: local adaptation, selection, cattle, SNP50 BeadChip, PCAdapt , population subdivision References AKEY, J. M. et al. (2002) Interrogating a high-density SNP map for signatures of natural selection. Genome Research , vol. 12, pp. 1805-1814. doi: http://dx.doi.org/10.1101/gr.631202 ALLENDORF, F. W., HOHENLOHE, P. A. and LUIKART, G. (2010) Genomics and the future of conservation genetics. Nature Reviews Genetics , vol. 11, no. 10, pp. 697-709. doi: http://dx.doi.org/10.1038/nrg2844 BIERNE, N., ROZE, D. and WELCH, J. J. (2013) Pervasive selection or is it . . .? Why are F ST outliers sometimes so frequent?. Molecular Ecology , vol. 22, pp. 2061-2064. doi: http://dx.doi.org/10.1111/mec.12241 DRUET, T. et al. (2013). Identification of large selective sweeps associated with major genes in cattle. Animal Genet ics, vol. 44, pp. 758-762. doi: http://dx.doi.org/10.1111/age.12073 DUFORET-FREBOURG, N. et al. (2015) Detecting genomic signatures of natural selection with principal component analysis: application to the 1000 genomes data. Molecular biology and evolution , vol. 33, pp. 1082-1093. doi: http://dx.doi.org/10.1093/molbev/msv334 DUFORET-FREBOURG, N., BAZIN, E. and BLUM, M. G. B. (2014) Genome scans for detecting footprints of local adaptation using a bayesian factor model. Molecular biology and evolution , vol. 31, pp. 2483-2495. doi: http://dx.doi.org/10.1093/molbev/msu182 FERENCAKOVIC, M., SOLKNER, J. and CURIK, I. (2013) Estimating autozygosity from high-throughput information: effects of SNP density and genotyping errors. Genetic Selection Evolution , vol. 45, no. 1, pp. 42. doi: http://dx.doi.org/10.1186/1297-9686-45-42 Flori, L. et al. (2009) The genome response to artificial selection: a case study in dairy cattle. PLoS One , vol. 4, e6595. doi: http://dx.doi.org/10.1371/journal.pone.0006595 GIUSTI, J. et al. (2013) Expression of genes related to quality of Longissimus dorsi muscle meat in Nellore ( Bos indicus ) and Canchim (5/8 Bos taurus × 3/8 Bos indicus ) cattle. Meat Science , vol. 94, no. 2, pp. 247-252. doi: http://dx.doi.org/10.1016/j.meatsci.2013.02.006 GOWANE, G. R. et al. (2014) The Expression of IL6 and 21 in Crossbred Calves Upregulated by Inactivated Trivalent FMD Vaccine. Animal Biotechnology , vol. 25, no. 2, pp. 108-118. doi: http://dx.doi.org/10.1080/10495398.2013.834826 GUTIERREZ-GIL, B., ARRANZ, J. J. and WIENER, P. (2015) An interpretive review of selective sweep studies in Bos taurus cattle populations: identification of unique and shared selection signals across breeds. Frontiers genetics , vol. 6, pp. 167. doi: http://dx.doi.org/10.3389/fgene.2015.00167 LUU, K., BAZIN, E. and BLUM, M. G. B. (2016) pcadapt: An R package for performing genome scans for selection based on principal component analysis. bioRxiv . doi: http://dx.doi.org/10.1101/056135 MANCINI, G. et al. (2014 ) Signatures of selection in five Italian cattle breeds detected by a 54K SNP panel. Molecular Biology Reports , vol. 41, pp. 957-965. doi: http://dx.doi.org/10.1007/s11033-013-2940-5 MARTINS, H. et al. (2016) Identifying outlier loci in admixed and in continuous populations using ancestral population differentiation statistics. bioRxiv , p. 054585. doi: http://dx.doi.org/10.1101/054585 MCCLURE, M. C. et al. (2012) Genome-wide association analysis for quantitative trait loci influencing Warner–Bratzler shear force in five taurine cattle breeds. Animal Genetics , vol. 43, no. 6, pp. 662-673. doi: http://dx.doi.org/10.1111/j.1365-2052.2012.02323.x NIELSEN, R. (2005) Molecular signatures of natural selection. Annual Review of Genetics , vol. 39, pp. 197-218. doi: http://dx.doi.org/10.1146/annurev.genet.39.073003.112420 NOVEMBRE, J. et al. (2008) Genes mirror geography within Europe. Nature , vol. 456, pp. 98-101. doi: http://dx.doi.org/10.1038/nature07566 OLEKSYK, T. K., SMITH, M. W. and O'BRIEN, S. J. (2010) Genome-wide scan for footprints of natural selection. Philosophical Transactions of the Royal Society B: Biological Sciences , vol. 365, pp. 185-205. doi: http://dx.doi.org/10.1098/rstb.2009.0219 QANBARI, S. et al. (2011) Application of site and haplotype-frequency based approaches for detecting selection signatures in cattle. BMC Genomics , vol. 12, pp. 318. doi: http://dx.doi.org/10.1186/1471-2164-12-318 STELLA, A. et al. (2010) Identification of selection signatures in cattle breeds selected for dairy production. Genetics, vol. 185, pp. 1451-1461 . doi: http://dx.doi.org/10.1534/genetics.110.116111 STOREY, J. D. (2002) A direct approach to false discovery rates. Journal of the Royal Statistical Society, Series B, vol. 64, pp. 479-498. doi: http://dx.doi.org/10.1111/1467-9868.00346 WAPLES, R. S. and GAGGIOTTI, O. (2006) What is a population? An empirical evaluation of some genetic methods for identifying the number of gene pools and their degree of connectivity. Molecular Ecology , vol. 15, pp. 1419-1439. doi: http://dx.doi.org/10.1111/j.1365-294x.2006.02890.x WEIR, B. S. et al. (2005). Measures of human population structure show heterogeneity among genomic regions. Genome Research , vol. 15, no. 11, pp. 1468-1476. doi: http://dx.doi.org/10.1101/gr.4398405 ZHAO, F. et al. (2015) Detection of selection signatures in dairy and beef cattle using high-density genomic information. Genetic Selection Evolution , vol. 47, pp. 49. doi: http://dx.doi.org/10.1186/s12711-015-0127-3

Syringophilopsis elongatus (Ewing, 1911) Syringophilus elongatus Ewing, 1911: 39. Type material lost (in Kethley: 21). Syringophilus icteridae Clark, 1964: 89, figs. 30 and 31. Material deposited in FMNH, examined. Syringophilopsis elongatus, Kethley 1970: 21, figs. 10 and 11; Bochkov & Galloway 2001: 2023; Skoracki et al. 2008: 299, 2011: 19. Type host: Agelaius phoeniceus (Linnaeus) (Passeriformes: Icteridae). Type locality: USA. Additional material. One female (FMNH A600507-6) from Agelaius phoeniceus (Linnaeus) (Passeriformes: Icteridae), USA: Nebraska, Saline Co., Crete, 7 May 1960, coll. N. Braasch, specimen in FMNH; 2 females (FMNH uncatalogued) from Quiscalus quiscula (Linnaeus) (Passeriformes: Icteridae), USA: Nebraska, Lincoln, 4 September 1944, coll. D. Gates, all material in FMNH. Host and distribution. Agelaius phoeniceus (Linnaeus) (Icteridae) from USA (Arizona, California, Georgia, Maryland, Nebraska) (Ewing 1911; Clark 1964; Kethley 1970; Skoracki et al. 2008, 2011a; present paper) and Canada (Manitoba) (Hood & Welch 1980), Euphagus carolinus (Muller) from USA (Maryland) (Clark 1964), Euphagus cyanocephalus (Wagler) from USA (California) (Skoracki et al. 2008), Quiscalus quiscula (Linnaeus) from USA (Maryland, Nebraska) (Clark 1964; present paper) and Canada (Manitoba) (Bochkov & Galloway 2001), Quiscalus mexicanus (Gmelin) from USA (Texas) (Casto 1976). Remark. Mite species recorded by Casto (1976) from Pheucticus melanocephalus (Cardinalidae) and determined as S. elongatus is presently described as a new species, S. wilsoni sp. nov. (see below)., Published as part of Skoracki, Maciej, Spicer, Greg S. & Oconnor, Barry M., 2016, A systematiC review of the subfamily Syringophilinae (ACari: Syringophilidae) of the NearCtiC region. Part 1: quill mites assoCiated with passerines (Aves: Passeriformes), pp. 451-494 in Zootaxa 4084 (4) on page 473, DOI: 10.11646/zootaxa.4084.4.1, http://zenodo.org/record/1052257, {"references":["Ewing, H. E. (1911) Predaceous and parasitic Acarina. Psyche, 18, 37 - 43. http: // dx. doi. org / 10.1155 / 1911 / 234794.","Clark, G. M. (1964) The acarine genus Syringophilus in North American birds. Acarologia, 6, 76 - 92.","Kethley, J. B. (1970) A revision of the family Syringophilidae (Prostigmata: Acarina). Contributions of the American Entomological Institute, 5, 1 - 76.","Bochkov, A. V. & Galloway, T. D. (2001) Parasitic cheyletoid mites (Acari: Cheyletoidea) associated with passeriform birds (Aves: Passeriformes) in Canada. Canadian Journal of Zoology, 79, 2014 - 2028. http: // dx. doi. org / 10.1139 / cjz- 79 - 11 - 2014.","Hood, D. E. & Welch, H. E. (1980) A seasonal study of the parasites of the red-winged blackbird (Agelaius phoeniceus L.) in Manitoba and Arkansas. Canadian Journal of Zoology, 58, 528 - 537. http: // dx. doi. org / 10.1139 / z 80 - 073","Casto, S. D. (1976) Host records and observations of quill mites (Acarina: Syringophilidae) from Texas birds. Southwestern Entomologist, 1, 155 - 160."]}

Two literature computational methods for the prediction of the number of inner-sphere aqua ligands, q, have been applied to a test set of seven Gd(aminocarboxylate) complexes. The first method is based on the hypothesis that q should be proportional to the solvent-accessible surface area of the ligand-complexed Gd ion (Castonguay, L. A., Treasurywala, A. M., Caulfield, T. J., Jaeger, E. P., and Kellar, K. E. (1999) Prediction of q-Values and Conformations of Gadolinium Chelates for Magnetic Resonance Imaging. Bioconjugate Chem. 10, 958). The second method is based on the hypothesis that q-values can be deduced by examining series of steric energy versus ionic radii plots as a function of coordination number (Reichert, D. E., Hancock, R. D., and Welch, M. J. (1996) Molecular Mechanics Investigation of Gadolinium(III) Complexes. Inorg. Chem. 35, 7013). This study identifies deficiencies in these methods and, with respect to the first method, describes some apparent errors. Although neither method was reliable at predicting q, two alternate approaches based on either molecular mechanics strain thresholds or exposed Gd surface area thresholds are shown to predict observed q-values for all Gd aminocarboxylate complexes in the test set.

Metal-ion, metal-sulfur, and metal-air batteries have recently attracted tremendous interests owing to their much higher gravimetric and volumetric energy densities as compared to conventional Li-ion batteries (LIBs). The metallic anodes employed in these next-generation batteries include Li, Na, Mg, Al, and Zn.1 So far, great effort has been devoted on the research of high-performance cathode materials. However, many technical issues associated with the metallic anodes such as dendritic growth, formation of passivation layer, as well as incomplete dissolution, have yet to be addressed. Moreover, the fundamental differences in the nature of these elements are far less exploited. To better understand the electrochemical behavior of metallic anodes, it is of importance to directly monitor their morphological and chemical evolution during the operation. There have been several attempts in developing new approaches toward this end over the past few years. In situ transmission electron microscopy (TEM) is expected to be a power tool for visualizing the dynamic processes of metallic anodes at a nanoscale.2,3 Most previous studies in this emerging field use a liquid cell with two silicon nitride windows to prevent vaporization of the electrolyte and involve demanding fabrication procedures. Besides, the presence of window materials largely reduces the image resolution. Take advantage of non-volatility of ionic liquids, herein, electrochemical behavior of metallic anodes was investigated by a specially designed window-less TEM holder. The miniature cell was composed of a counter electrode as the metal source, a modified TEM grid as the working electrode, and a sheet of IL-contained separator was hold between the electrodes. The cell was assembled in an Ar-filled glovebox and all the electrochemical measurements were conducted in the TEM chamber using a potentio/galvanostat. The typical images obtained are shown in Figure 1. In the instance of Li, three distinct types of deposits are identified (fiber, moss, film). It is worth mentioning that most of the Li microstructures reported essentially fall into these three categories, implying that our TEM results are representative of the actual electrodes. Majority of the deposits possess a fiber-like structure. These images are of good resolution and fairly consistent with the common dendrite morphology observed by ex situ SEM. With the help of window-less configuration, we can confirm that the deposits are fully covered with a thin solid electrolyte interphase (SEI) of a thickness of 10–20 nm. Furthermore, electron diffraction analysis is applicable for revealing the structural and compositional information of the deposits. These findings encourage us to further exploring other metallic anodes and comparing the features of each metal system. In summary, our approach provides possibilities to rapidly scrutinize the interface between the electrode and the non-volatile electrolyte, e.g., ionic liquid, glass- and ceramic-based electrolytes, for future secondary battery applications. Part of this research was supported by the Grant-in-Aid for Scientific Research, Grant Numbers 15H03591, 15K13287, and 15H2202 from the Japanese Ministry of Education, Culture, Sports, Science and Technology and by the ALCA-SPRING program, Japan Science and Technology Agency. References 1. H. Kim, G. Jeong, Y. U. Kim, J. H. Kim, C. M. Park, and H. J. Sohn, Chem. Soc. Rev., 42, 9011 (2013). 2. B. L. Mehdi, J. Qian, E. Nasybulin, C. Park, D. A. Welch, R. Faller, H. Mehta, W. A. Henderson, W. Xu, C. M. Wang, J. E. Evans, J. Liu, J. G. Zhang, K. T. Mueller, and N. D. Browning, Nano. Lett., 15, 2168 (2015). 3. Y. M. A. Wu, Z. W. Yin, M. Farmand, Y. S. Yu, D. A. Shapiro, H. G. Liao, W. I. Liang, Y. H. Chu, and H. M. Zheng, Sci. Rep., 7, 42527 (2017). Figure 1

Five years ago, the Point-Counterpoint series was launched. The initial article asked about the role of rapid immunochromatographic antigen testing in the diagnosis of influenza A virus 2009 H1N1 infection (D. F. Welch and C. C. Ginocchio, J Clin Microbiol 48:22–25, 2010, http://dx.doi.org/10.1128/JCM.02268-09). Since that article, not only have major changes been made in immunochromatographic antigen detection (IAD) testing for the influenza viruses, but there has also been rapid development of commercially available nucleic acid amplification tests (NAATs) for influenza virus detection. Further, a novel variant of influenza A, H7N9, has emerged in Asia, and H5N1 is also reemergent. In that initial article, the editor of this series, Peter Gilligan, identified two issues that required further consideration. One was how well IAD tests worked in clinical settings, especially in times of antigen drift and shift. The other was the role of future iterations of influenza NAATs and whether this testing would be available in a community hospital setting. James Dunn, who is Director of Medical Microbiology and Virology at Texas Children's Hospital, has extensive experience using IAD tests for diagnosing influenza. He will discuss the application and value of these tests in influenza diagnosis. Christine Ginocchio, who recently retired as the Senior Medical Director, Division of Infectious Disease Diagnostics, North Shore-LIJ Health System, and now is Vice President for Global Microbiology Affairs at bioMérieux, Durham, NC, wrote the initial counterpoint in this series, where she advocated the use of NAATs for influenza diagnosis. She will update us on the commercially available NAAT systems and explain what their role should be in the diagnosis of influenza infection.

Syringophilopsis elongatus (Ewing, 1911) Syringophilus elongatus Ewing, 1911: 39 Syringophilopsis elongatus Kethley 1970: 21, figs. 10 and 11 Syringophilus icteridae Clark, 1964: 89, figs. 30 and 31 This species was described originally from Agelaius phoeniceus (Linnaeus) (Icteridae) collected from Maryland and Georgia (Ewing 1911; Kethley 1970). After the first description it has been recorded from five additional host species: ex Quiscalus quiscula (Linnaeus) (Icteridae) from Canada (Manitoba) (Hood & Welch 1980; Bochkov & Galloway 2001) and U.S. A (Maryland) (Clark 1964; Kethley 1970), ex Quiscalus mexicanus (Gmelin) (Icteridae) from U.S.A. (Texas) (Casto 1976), ex Euphagus carolinus (M��ller) (Icteridae) from U.S. A (Maryland) (Clark 1964), ex Euphagus cyanocephalus (Wagler) (Icteridae) from U.S. A (California) (Skoracki et al. 2008), ex Pheucticus melanocephalus (Swainson) (Cardinalidae) from U.S.A. (Texas) (Casto 1976). Below we give new records of this species found on two host species in Arizona and California. Material examined. 12 females from quill of the Red-winged Blackbird Agelaius phoeniceus (Linnaeus) (Icteridae); United States, Arizona, Cibola NWR, 25 November 2006, coll. G. Spicer (GSS# 1950). All material is deposited in the NMNH except 4 females in the AMU (AMU���SYR. 306 a); 4 females, 1 male, and 7 nymphs from same host, United States, California, Riverside Co., 7 April 2007, coll. G. Spicer (GSS# 2122). All material is deposited in the AMU (AMU���SYR. 306 b); 2 females and 2 nymphs from quill of the Great-tailed Grackle Quiscalus mexicanus (Gmelin) (Icteridae); United States, 29 March 2004, coll. G. Spicer (GSS# 2544). All material is deposited at AMU (AMU���SYR. 307)., Published as part of Skoracki, Maciej, Hendricks, Sarah A. & Spicer, Greg S., 2011, Systematics of the genus Syringophilopsis Kethley, 1970 (Acari: Prostigmata: Syringophilidae) with description of three new species from North American passerines, pp. 1-22 in Zootaxa 2793 on page 19, DOI: 10.5281/zenodo.205181, {"references":["Kethley, J. B. (1970) A revision of the family Syringophilidae (Prostigmata: Acarina). Contributions of the American Entomological Institute, 6, 1 - 76.","Clark, G. M. (1964) The acarine genus Syringophilus in North American birds. Acarologia, 6, 76 - 92.","Hood, D. E. & Welch, H. E. (1980) A seasonal study of the parasites of the red-winged blackbird (Agelaius phoeniceus L.) in Manitoba and Arkansas. Canadian Journal of Zoology, 58, 528 - 537.","Bochkov, A. V. & Galloway, T. D. (2001) Parasitic cheyletoid mites (Acari: Cheyletoidea) associated with passeriform birds (Aves: Passeriformes) in Canada. Canadian Journal of Zoology, 79, 2014 - 2028.","Casto, S. D. (1976) Host records and observations of quill mites (Acarina: Syringophilidae) from Texas birds. Southwestern Entomologist, 1, 155 - 160.","Skoracki, M., Flannery, M. E. & Spicer, G. S. (2008) Quill mites of the genus Syringophilopsis Kethley, 1970 (Acari: Syringophilidae) from North American birds. Folia Parasitologica, 55, 291 - 300."]}

Several novel diodes to control the 19 MeV, 700 kA electron beam and subsequent bremsstrahlung from the HERMES III accelerator [Ramirez et al., Digest of Technical Papers of the 6th IEEE Pulse Power Conference (IEEE, New York, 1987), p. 294] have been designed and tested for the study of nuclear radiation effects. The electron beam has been propagated over 10 m in low‐pressure gas cells. A comprehensive set of diagnostics has been developed to characterize the performance of these diodes, beams, and radiation fields. The observed performance has been compared with models that combine the simulation of electron flow, using the magic particle‐in‐cell (PIC) code [ Pointon, J. Comput. Phys. (in press)] with simulation of electron‐photon transport in bremsstrahlung targets, using the cyltran Monte Carlo code [Halbleib and Mehlhorn, Nucl. Sci. Engl. 92, 338 (1986)]. Beam transport results have been compared with iprop PIC code [B. B. Godfrey and D. R. Welch, Twelfth Conference on Numerical Simulation of Plasmas...

The mercury machine at NRL, formerly known as KALIF-HELIA [P. Hoppe et al., June 17-22, 2001] at Forschungszentrum Karlsruhe (Germany), is a magnetically-insulated inductive voltage adder (MIVA), nominally delivering a 50-ns, 6-MV, 360-kA, 2.2-TW power pulse into a 16-/spl Omega/ load [R. J. Commisso et al., R. J. Allen et al., P. F. Ottinger et al., 2003]. Mercury is capable of operating in both positive and negative polarities with little penalty in pulsed-power output. Polarity reversal is achieved by insertion of the tapered center conductor into the opposite end of the MIVA. In this work, particle-in-cell (PIC) simulations [B. Goplen et al., 1995; D. R. Welch et al., 2001] are used to investigate the power flow within the magnetically-insulated transmission line (MITL) in both polarities. Of particular importance is the efficiency of operation when an over-matched 50-/spl Omega/ rod-pinch-diode load is couple to the MITL, operated in either positive [G. Cooperstein et al., 2001] or negative [G. Cooperstein et al., 2003] polarity. Such a diode is used for radiographic applications because of the small, high brightness radiation source produced by the electron pinch at the end of the diode's anode rod [R. J. Commisso et al., 2002]. Simple positive and negative polarity diode geometries are studied in preparation for initial rod-pinch diode experiments on mercury.

A blog by D. R. Welch on health problems of astronaut Steve Bell, stationed at the space station International Space Station (ISS), is presented.

A blog from D. R. Welch on the Republican Party's stand on budget deficit and Medicare spending is presented.

A blog by D. R. Welch is discussed in which he comments on the debate regarding National Public Radio (NPR) funding.

We report measurements of the transmission of 1 - 6-keV energy positrons through films of Al, Cu, and Si up to 3000 \AA{} thick. When the thickness is expressed in terms of mass per unit area, the transmission of Cu and Al is found to be the same within \ifmmode\pm\else\textpm\fi{}10%. Within a \ifmmode\pm\else\textpm\fi{}20% precision we observe no effect having to do with the crystallinity of the materials. The median penetration depth of positrons in Al and Cu is found to vary with the energy $E$ as ${E}^{n}$, with $n={1.60}_{\ensuremath{-}0.08}^{+0.15} \mathrm{and} {1.43}_{\ensuremath{-}0.11}^{+0.07}$, respectively. Our measured median penetration depths are significantly less than one would have expected from the calculation of Nieminen and Oliva [R. M. Nieminen and J. Oliva, Phys. Rev. B 22, 2226 (1980)] which seems to indicate the importance of large-angle scattering effects. Our measurements can be combined with independent measurements of the energy dependence of the yield of positronium at a surface [K. G. Lynn, Phys. Rev. Lett. 44, 1330 (1980) and K. G. Lynn and D. O. Welch, Phys. Rev. B 22, 99 (1980)] to obtain values for the positron diffusion constant ${D}_{+}$ in single-crystal metal samples. For example, we find ${D}_{+}(\mathrm{Al})=(0.76\ifmmode\pm\else\textpm\fi{}0.14)$ ${\mathrm{cm}}^{2}$ ${\mathrm{sec}}^{\ensuremath{-}1}$ and ${D}_{+}(\mathrm{Cu})=(1.06\ifmmode\pm\else\textpm\fi{}0.20)$ ${\mathrm{cm}}^{2}$ ${\mathrm{sec}}^{\ensuremath{-}1}$. The former is in agreement with the deformation-potential calculation of Bergersen et al. B. Bergersen, E. Pajanne, P. Kubica, M. J. Stott, and C. H. Hodges, [Solid State Commun. 15, 1377 (1974)] if the positron effective mass in Al is ${m}_{+}=(1.59\ifmmode\pm\else\textpm\fi{}0.12){m}_{e}$. Finally, we use our measurements to calculate the optimum thickness of transmitting positron moderators for enhancing the brightness of slow positron beams.

Two free-ranging moose (Alces alces) cows were used to study seasonal changes in voluntary intake between December 1982 and January 1984. Observations of each animal were made during a continuous 24-hour period every 6-8 weeks. Dry matter intake was estimated from the ratio of total dry matter in the feces to the percent indigestibility of dietary dry matter and from the bite-count technique. During the 1-year period, dry matter intake ranged from 37.8 g/kg BWo075 in January to 128.5 g/kg BW0-75 during July. The bite-count technique estimated voluntary intakes which were within 6% of those calculated from total fecal collections. Dry matter digestibility of selected diets ranged from 71% in late May to 44% in late January as estimated by the in situ nylon bag technique. Crude protein content in the feces was correlated (P < 0.05) with digestible dry matter intake (r2 = 0.88) and with the nitrogen content of simulated diets (r2 = 0.95). Nylon bag dry matter digestibility of simulated diets was highly correlated (P < 0.001) with diet dry matter (r2 = 0.73), crude protein (r2 = 0.69), and neutral detergent fiber (r2 = 0.90). The maintenance energy requirement for a free-ranging moose cow, estimated by least squares linear regression, was 399 KJ/ kg BW075 daily. J. WILDL. MANAGE. 49(3):785-792 Seasonal variations in forage intake by freeranging ungulates express the interactions of animal requirements and wide fluctuations in diet quality and availability. Schwartz et al. (1981) showed that penned Alaska moose fed a pelleted ration reached peak intake during summer and low points during the breeding season and late winter. Miquelle (1979) reported dry matter intakes of young moose on Isle Royale during summer from pen trials with clipped browse and of free-ranging moose using the bite-count technique. Crete and Bedard (1975) and Nystr6m (1980) estimated browse consumption for moose in Quebec and Sweden, respectively, using modified versions of the twigcount technique. Approximate calculations of daily food consumption by moose were made by Gasaway and Coady (1974) based on seasonal differences in rumen fill. However, few empirical data are available on seasonal forage intake of free-ranging moose. Several methods for determining forage intake of free-ranging animals have been published. Among these, ratio and bite-count methods are most practical for studies on wild ruminants. The ratio technique (fecal excretion/indigestibility of the diet) appears most reliable for estimations of intake by grazing livestock (Cordova et al. 1978). Measures of fecal output are usually combined with an in vitro estimate of diet digestibility from esophageal samples (Allison et al. 1982, Holechek and Vavra 1982). However, fecal output also can be determined indirectly using external markers (indigestible indicators attached to diet particles) and digestibility can be estimated with indigestible internal markers such as lignin or silica (Langlands 1975, Engdahl 1976). The bitecount technique, a useful alternative for less tractable animals, has been used to estimate feeding rates and daily intake by wapiti (Cervus elaphus nelsoni) (Collins 1977, Hobbs 1979, Ni tfeld 1983, Wickstrom 1983), mule deer (Odocoileus hemionus) (Wickstrom 1983), and moose (Miquelle 1979). Accurate measurement of bite rate, simulated bite size, and total foraging time are required for a reliable predictio of voluntary intake. This study determined seasonal changes in dry matter consumption by habituated freeranging moose using both ratio and bite-count methods. We acknowledge the financial support of Alberta Recreation, Parks and Wildl. Found., Agric. Res. Counc. of Alberta, The Alberta Env ron. Trust, and the Nat. Sci. and Eng. Res. Counc. We wish to thank D. M. Renecker, D. M. Bayne, M. T. Nietfeld, C. D. Olsen, L. R. Griffith, M. H. Griffith, A. J. Keith, K. L. Risenhoover, and D. A. Welch for their skillful assistance in data collection. Special thanks to D. M. Renecker and C. D. Olsen for their helpful comments on the manuscript.

Foraging rates of free-ranging moose (Alces alces) in aspen (Populus spp.) boreal habitats were evaluated in summer, autumn, and winter. Consumption rates (g/min) increased asymptotically with biomass of potential forage, but both maximum rates and slopes varied seasonally. Maximum rates appeared related to forage quality since values declined from 23 g/minute in July to 11 g/minute in January. Slopes reflecting increments of foraging rate/unit increase in biomass seemed related to selectivity exercised by moose. The highest values were observed in winter when moose were least selective, the lowest in October when a mixture of green and cured forage offered the greatest opportunities for selective feeding. J. WILDL. MANAGE. 50(1): 143-147 Seasonal changes in the quality and availability of forage potentially limit daily food intake by moose throughout much of their biogeographical range. The ultimate constraint on dry matter intake for ruminants is rumen fill and hence rates of digestion and passage which are strongly influenced by physicochemical properties of forage. At another level, biomass and structure of vegetation influence feeding rates imposing an additional logistic constraint, particularly for large herbivores feeding in sparse habitats. Longer foraging times, higher biting rates, or greater bite sizes are tactics that herbivores can use to meet their daily forage requirements (Wickstrom et al. 1984). Total time devoted to feeding can be limited by search times and the need to ruminate while compensatory limits on bite rates and sizes are often dictated by vegetation characteristics. Following pioneering work on domestic animals (Allden and Whittaker 1970, Chacon and Stobbs 1976), several investigators have studied the intensity with which wild ungulates harvest food. The earliest of these considered feeding rates in relation to habitat type (Collins et al. 1978). This was followed by studies designed to determine how forage biomass and structure influenced feeding behavior of such species as caribou (Rangifer tarandus) (Trudell and White 1981), mule deer (Odocoileus hemionus) (Wickstrom et al. 1984), and elk (Cervus elaphus) (Nietfeld 1983, Wickstrom et al. 1984, Hudson and Nietfeld 1985). Comparable studies have not been conducted on large browsers such as moose. VivAs (in press) measured winter consumption rates of woody stems by moose in Norway, and Renecker and Hudson (1985) documented seasonal changes in dry matter intake by moose in central Alberta. But these measures have not been related to seasonal forage supplies. This study examined the logistics of foraging by moose in the aspen boreal environment and provided data on how seasonal changes in biomass of selected forages influenced feeding rates. Financial support was received from Alberta Rec., Parks and Wildl. Found., Agric. Res. Counc. Alberta, Alberta Envir. Trust, and Nat. Sci. and Eng. Res. Counc. We thank D. M. Renecker, D. M. Bayne, M. T. Nietfeld, C. D. Olsen, A. J. K ith, M. Young, and D. A. Welch for their skillful assistance in the field and R. G. Weingardt for help with statistical analysis.

This report includes: Measurement of stacking fault probabilities in bulk specimens by Henry M. Otte, D. O. Welch and G. F. Bolling. In x-ray diffraction measurements of NaN3 it has been noted that after deformation, the line broadening was consistent with that expected from formation of deformation stacking faults. However, the anticipated shifts in the peak positions could not be detected. An explanation for this is suggested on the basis of the supposition that (1) extrinsic stacking faults are at least as likely to form in NaN3 as intrinsic stacking faults and (2) x-ray diffraction analysis for extrinsic stacking faults is applicable.