121 research outputs found
Book Review - The Iowa Breeding Bird Atlas
The Iowa Breeding Bird Atlas is the first comprehensive statewide survey of Iowa\u27s breeding birds. Through the efforts of over 500 people, every county in the state was sampled to provide a record of the composition and distribution of the bird life in Iowa. The project entailed dividing the state into 861 atlas blocks; 83% received at least some coverage and 71 % were completed. Information known through 1995 is included in the text, although the atlas project ended in 1990
Wildlife use of terraces in Iowa rowcrop fields
Terracing is a soil conservation practice that has been promoted throughout the Midwest since the days of the Dust Bowl era. The benefits for controlling soil erosion are well-documented, but the values to wildlife are much less clear. This study documented the numbers and species of birds and small mammals as well as the number of small mammal dens in southwest Iowa terraces
On the Rarity of Food Provisioning by Male Dickcissels
Males of polygynous bird species typically provide less parental care to their offspring than males of monogamous species (Ketterson and Nolan 1994). Generally, in polygynous species, a male forfeits some potential reproductive success ifhe shifts his reproductive effort from mating with multiple females to parental care (Trivers 1972, Gubemick et al. 1993, Schleicher et al. 1993). In the polygynous dickcissel (Spiza americana), singing and foraging activities constitute much of a male\u27s time-activity budget (Schartz and Zimmerman 1971, Finck 1984). Although male dickcissels are attentive to their nests and mates (e.g., nest protection and vigilance) females incubate the eggs and feed the young (Gross 1921). Herein, we describe an account ofa male dickcissel feeding brown-headed cowbird (Molothrus ater) young early in the breeding season, summarize and review previous reports of food provisioning by the male dickcissel, and discuss the rarity of this behavior in the dickcissel
Winter Bird Use of Conservation Reserve Program Fields Harvested for Biomass
As Conservation Reserve Program (CRP) contracts expire, many fields may be returned to agricultural production. Growing switchgrass (Panicum virgatum) as a biomass fuel is an alternative to returning fields to rowcrops. CRP fields provide winter cover for birds, but the harvest of biomass would remove most of the cover and affect bird use of the fields. We estimated winter bird abundances in nonharvested, total-harvested, and partially (strip) harvested switchgrass fields in southern Iowa. Song sparrows (Melospiza melodia) were observed only in strip-harvested fields and ring-necked pheasants (Phasianus colchicus) were observed only in nonharvested fields and uncut areas of strip-harvested fields. American tree sparrows (Spizella arborea) were observed in all three treatments, but abundances were not significantly different among treatments. Tree sparrows, however, were observed more often in uncut strips of strip-harvested fields than in cut strips, with 87% of observations in strip-harvested fields in uncut strips. Abundances in strip-harvested fields were in general higher than abundances in rowcrop and CRP plantings in other studies. Strip-harvested switchgrass fields may be more beneficial in winter than total-harvested fields, rowcrop, or idle CRP fields for some bird species
Winter Bird Use of Conservation Reserve Program Fields Harvested for Biomass
As Conservation Reserve Program (CRP) contracts expire, many fields may be returned to agricultural production. Growing switchgrass (Panicum virgatum) as a biomass fuel is an alternative to returning fields to rowcrops. CRP fields provide winter cover for birds, but the harvest of biomass would remove most of the cover and affect bird use of the fields. We estimated winter bird abundances in nonharvested, total-harvested, and partially (strip) harvested switchgrass fields in southern Iowa. Song sparrows (Melospiza melodia) were observed only in strip-harvested fields and ring-necked pheasants (Phasianus colchicus) were observed only in nonharvested fields and uncut areas of strip-harvested fields. American tree sparrows (Spizella arborea) were observed in all three treatments, but abundances were not significantly different among treatments. Tree sparrows, however, were observed more often in uncut strips of strip-harvested fields than in cut strips, with 87% of observations in strip-harvested fields in uncut strips. Abundances in strip-harvested fields were in general higher than abundances in rowcrop and CRP plantings in other studies. Strip-harvested switchgrass fields may be more beneficial in winter than total-harvested fields, rowcrop, or idle CRP fields for some bird species
Life History and Status Classifications of Birds Breeding in Iowa
Life history and status classifications were compiled for 145 bird species that breed in Iowa. Species were classified by food type and substrate, nest substrate, susceptibility to cowbird parasitism, migratory status, predominant habitat use and habitat-use specialization, body mass (an index of home range/territory size), area sensitivity, population trend and vulnerability, and beneficial/harmful aspects in relation to agriculture. Such information may be used to make interspecific comparisons, evaluate interrelationships among life history and status characteristics, and provide insights into the interpretation of previous research. This synthesis also can aid those responsible for making conservation and management decisions about Iowa\u27s avifauna
Energy transfer in nonlinear network models of proteins
We investigate how nonlinearity and topological disorder affect the energy
relaxation of local kicks in coarse-grained network models of proteins. We find
that nonlinearity promotes long-range, coherent transfer of substantial energy
to specific, functional sites, while depressing transfer to generic locations.
Remarkably, transfer can be mediated by the self-localization of discrete
breathers at distant locations from the kick, acting as efficient
energy-accumulating centers.Comment: 4 pages, 3 figure
Topology Change in Canonical Quantum Cosmology
We develop the canonical quantization of a midisuperspace model which
contains, as a subspace, a minisuperspace constituted of a
Friedman-Lema\^{\i}tre-Robertson-Walker Universe filled with homogeneous scalar
and dust fields, where the sign of the intrinsic curvature of the spacelike
hypersurfaces of homogeneity is not specified, allowing the study of topology
change in these hypersurfaces. We solve the Wheeler-DeWitt equation of the
midisuperspace model restricted to this minisuperspace subspace in the
semi-classical approximation. Adopting the conditional probability
interpretation, we find that some of the solutions present change of topology
of the homogeneous hypersurfaces. However, this result depends crucially on the
interpretation we adopt: using the usual probabilistic interpretation, we find
selection rules which forbid some of these topology changes.Comment: 23 pages, LaTex file. We added in the conclusion some comments about
path integral formalism and corrected litle misprinting
Recommended from our members
1961
My Ideal Course, Underwater, U.S.A. (page 1) From the Editor (3) Turf Management Club News (3) Quotes from 1961 Seniors (4) The United States Most Western Owned Golf Course: Armed Forces Golf Course, Guam (5) Turf Majors Participate in Horticultural Show (7) Picture - G.C.S.A Scholarships Awarded to Three Turf Seniors (8) Picture - Stockbridge - Majors in turf Management (9) Opportunity and Education (10) The Most Outstanding Turf Senior for the Year - 1961 (11) How We Prepare Our Greens Before Topdressing (12) An Inexpensive Cure for Weeds and Poa Annua (13) Watering (14) Picture - Honorary Members of the Turf Management Club (16) Picture - Graduates of Winter School for Turf Managers - 1961 (17) Welcome Speech by Narry Sperandio (A-1) Handle with Care by Dr. Ellsworth H. Wheeler (A-2) Current Ideas on Green Construction - Panel Discussion (A-4) Automatic Systems for Watering by Robert F. Harper (A-14) History of Golf Course Architecture by Geoffrey S. Cornish (A-22) Effect of Nutrition on Turf Diseases by Dr. Houston B. Couch Turf Disease Control and Use of Fungicides by Dr. R. J. Lukens Trees and Tree Care by Gordon S. King (A-38) Arsenical Toxicity by Dr. C. R. Skogley (A-41) Soil Reaction to Arsenical Compounds by Joseph E. Steckel Brush Control For the Golf Course by Dr. William I. Boyd (A-51) Massachusetts Highway Herbicide Program by Joseph L. Beasley (A-54) General Turf (Alternate Session): Observations on Highway Turf Establishment & Maintenance by E.F. Button (A-62) Pre-emerge Chemicals for the Control of Crabgrass by Dr. John R. Havis, John M. Zak & Joseph Troll (A-70) Root Growth of Turf Grasses as Affected by Different heights of Cut and Nutrient Levels by Evangel J. Bredakis (A-71) The Use of Sod by Daniel Pellegrino (A-72
Multitrait analysis of glaucoma identifies new risk loci and enables polygenic prediction of disease susceptibility and progression
Glaucoma, a disease characterized by progressive optic nerve degeneration, can be prevented through timely diagnosis and treatment. We characterize optic nerve photographs of 67,040 UK Biobank participants and use a multitrait genetic model to identify risk loci for glaucoma. A glaucoma polygenic risk score (PRS) enables effective risk stratification in unselected glaucoma cases and modifies penetrance of the MYOC variant encoding p.Gln368Ter, the most common glaucoma-associated myocilin variant. In the unselected glaucoma population, individuals in the top PRS decile reach an absolute risk for glaucoma 10 years earlier than the bottom decile and are at 15-fold increased risk of developing advanced glaucoma (top 10% versus remaining 90%, odds ratio = 4.20). The PRS predicts glaucoma progression in prospectively monitored, early manifest glaucoma cases (P = 0.004) and surgical intervention in advanced disease (P = 3.6 × 10). This glaucoma PRS will facilitate the development of a personalized approach for earlier treatment of high-risk individuals, with less intensive monitoring and treatment being possible for lower-risk groups
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