bluuebunny/crossref_metadata_2025_split huggingface dataset:
Managing to sustain vertebrate richness in forests of the Pacific Northwest: relationships within stands
Authors: Bunnell F L , Kremsater L L , Wind E 
Published: April 2011

Many regions confront potentially competing goals: sustaining biological diversity and extracting wood products from forests rich in biological diversity. Forests of the Pacific Northwest are particularly rich in vertebrates. Because little is known of many species, management tactics to sustain vertebrate richness must employ interim surrogates that credibly reflect responses of groups of vertebrates. These tactics should focus on elements of the forest, commonly altered by forest practices, to which groups of species are closely linked. We identify five such elements for forests of the Pacific Northwest: dead and dying trees, downed wood, shrubs, hardwoods (broadleaved, deciduoustrees), and riparian areas. Most forest-dwelling vertebrates in the Pacific Northwest, including those designated "at risk", require one or more of these forest elements. Late-successional forests represent particular mixes of these elements. Each element can be altered in ways that benefit or harm specific groups of species. Any management decision, including taking no action at all, favours some species while disadvantaging others. We report the proportions of the vertebrate fauna associated with the five forest elements, plus early- and late-successional stages for a range of forest types. The nature of relationships with each forest element is quantified by biologically appropriate measurements (e.g., decay state, tree species, snag density, and tree size for cavity sites). Impacts of current practices are summarized and tactics appropriate for maintaining vertebrates are described. Responses of organisms other than vertebrates are noted. Key words: forest practices, Pacific Northwest, vertebrate richness.
Pollination effects on patterns of ovule fate in Hesperis matronalis (Brassicaceae)
Authors: Susko David J. , Clubb Michelle 
Published: April 2011

We examined ovule positional effects on patterns of ovule development within linear fruits of the invasive weed, dame’s rocket, Hesperis matronalis L. Fruits were collected from two sites in southwestern Ontario, Canada. The majority of ovules within fruits were aborted early in development. Emergent patterns of ovule abortion and seed maturation within fruits were nonrandom and dependent on ovule position. The probability of seed maturation within individual fruits decreased significantly from basal to distal ends, suggesting an intrafruit resource gradient. Self-pollinated flowers at one site produced fruits with a similar pattern of seed maturation as was found for open-pollinated plants. However, cross-pollinated flowers produced fruits in which the pattern of seed maturation was reversed; more seeds were matured at the distal ends rather than the basal ends of fruits, indicative of a fertilization gradient. Analysis of pollen-tube growth showed that ovule failure may not be attributed to pollen limitation. For seeds produced via hand-pollinations, we found no relationship between seed mass and seedling biomass, although seeds from self-pollinations germinated more readily than did seeds from cross-pollinations. While patterns of ovule fate in H. matronalis can be manipulated by pollen source, the effects of such patterns on plant fitness are yet to be determined.
Exposure to aphids increases alder growth and nitrogen fixation
Authors: Zekveld Corinthe , Markham John 
Published: April 2011

Plants can respond to herbivore damage by mounting a resistance response or by compensating for lost fitness. Both plant nutrition and interactions with soil microbes can affect these responses. It has been shown that resistance responses can occur before plants have been attacked by herbivores. Here we show that a tolerance type of response can occur when plants are exposed to, but not fed on by, herbivores. Alnus viridis (Chaix) DC. spp. crispa (Ait.) Turrill were grown in sealed containers under positive air pressure with either 0.5 mmol·L–1 or 2.0 mmol·L–1 nitrate and either inoculated or not inoculated with Frankia , their nitrogen-fixing symbiont. Plants were then exposed to the genus-specific aphid Prociphilus tessallatus Fitch, which failed to establish feeding colonies. Exposure to aphids, formation of nitrogen-fixing nodules, and elevated soil nitrogen levels all significantly increased plant yield with no interaction among these factors. A combination of high soil nitrogen, nodulation, and exposure to aphids resulted in the lowest plant root:shoot ratio. Plants that were grown with low nitrogen and were exposed to aphids showed increased nitrogen-fixing activity within a day of being exposed. These results provide further evidence to support the observation that plants can respond to cues from other organisms prior to receiving herbivore damage.
Ages at Migration of Atlantic Salmon (Salmo salar) in Miramichi River
Authors: Blair A. A. 
Published: April 2011

In 1,557 fish examined, the groups, based upon years in the sea and spawning marks, were:—grilse or 1+, 2 and 2+, 3 and 3+, and 1 S.M. and 2 S.M. groups. The 2 and 2+ form 85.1 per cent of the total (grilse excluded), and S.M. 12.8 per cent, and the 3 and 3+, 2.1 per cent. Of fish with one spawning mark, 68.3 per cent first spawned as grilse, 29.9 per cent after two sea winters, and 1.8 per cent after three sea winters. The S.M. group had 11 per cent return to river in less than a year after first spawning, the remainder in little better than a year. Most of the fish with two spawning marks had the same length of absence on both occasions. Only four smolt ages were found:—3 (78.1 per cent), 2 (15.1 per cent), 4 (6.6 per cent) and 5 (0.2 per cent).
The Growth of the Pacific Edible Crab, Cancer magister Dana
Authors: MacKay Donald C. G. , Weymouth Frank W. 
Published: April 2011

Approximately 20,000 measurements were made of crabs and cast exoskeletons, chiefly from Boundary bay, southern British Columbia. From size frequencies of crabs under 3 cm. seven modes have been identified as representing the early post-larval instars. Increase in size of animals in the laboratory or in live wells is significantly less than in nature, and leads to erroneous results when applied to growth. The increase per moult decreases from about 40 per cent in the early post-larval stages to about 15 per cent in males of 13.5 cm. and 10 per cent in females of 13.0 cm. Above 10 cm. the males increase more per moult. The intervals between moults become progressively longer with increasing size, and tagging experiments indicate that large crabs moult yearly. Probably to reach the maximum size, seventeen and sixteen post-larval instars are required for males and females respectively. Sexual maturity in female crabs is probably attained during the fourth or fifth year but may occur in the third or the sixth year. The legal size in British Columbia (6½ inches, or 16.5 cm.) is probably attained during the seventh or eighth year. The average duration of life is probably about eight years and the maximum age not more than ten years.
Factors Determining the Course of the Gastric Secretion in Elasmobranchs
Authors: Babkin B. P. , Chaisson A. F. , Friedman M. H. F. 
Published: April 2011

The continuous secretion of very small amounts of highly acid gastric juice in fasting skates (Raja diaphanes or R. erinacea) is unaffected by section of the vagi, injection of large doses of atropine, or subcutaneous introduction of histamine, but is inhibited for several hours by adrenaline or (to a less marked degree) by stimulation of the sympathetic. Destruction of the spinal cord (cervical region to tail) results in a "paralytic" secretion of gastric juice (sympathetic influence eliminated), commencing after 1 day and continuing up to even 16 days, with volume up to 30 cc. per day, pH from 2.0 to 5.0, and digestive power moderate. The freezing point depression of the juice becomes progressively lower (Cl concentration unaltered), as also that of the blood. Secretion considered as very probably the result of vascular changes in the viscera due to disconnection of peripheral and central parts of the sympathetic.
A Quantitative Study of the Phytoplankton in the Bay of Fundy and the Gulf of Maine (including Observations on Hydrography, Chemistry and Turbidity)
Authors: Gran H. H. , Braarud Trygve 
Published: April 2011

In the gulf of Maine life conditions of the phytoplankton were found to be in agreement with those described from the coastal waters of Northern Europe. The surface layers are during summer more or less stratified, indicating a fairly low degree of turbulence. Where the stratification is broken up, by vertical mixing, the waters are so transparent that the total effect of the turbulence on the productivity is favourable, the supply of nutrient salts resulting in an increase of the population, exceeding the loss by vertical transport. In the bay of Fundy, on account of the exceptionally high tidal range, the turbulence of the waters is so strong throughout the year that their nitrate and phosphate content nearly always was found to be high, even at the surface. The production of phytoplankton, therefore, can hardly be limited by the lack of nutrient salts. A relatively high turbidity of the waters and much cloudy weather make the productive zone shallow. Consequently the high degree of turbulence may even diminish the productivity of the waters by carrying the diatom cells down below the illuminated zone for a greater part of their life. A pronounced phytoplankton minimum in June probably is mainly a result of this effect of turbulence.
Fish Oils. VI. The Structure and Properties of Pilchard Oil Films
Authors: Denstedt O. F. , Brocklesby H. N. 
Published: April 2011

British Columbia pilchard oil dries more rapidly than linseed oil and yields substantial protective films. The films are softer and more tacky than those from linseed oil. They are more permeable to moisture, and show a tendency to become dull and to bloom. These defects can partly be corrected by the use of the proper drier combinations and incorporation of gums but they can be entirely eliminated only by steam distillation of the polymerized oil at high temperatures. The product of this treatment yields films superior to those of other drying oils in hardness, gloss, lower permeability and freedom from yellowing and blooming. The structure and properties of the films are discussed. The nature and distribution of the non-drying components in the film are described. Methods for estimating permeability and moisture absorption of films given and the influence of moisture as the primary agency in film disintegration is emphasized. The nature of yellowing, cissing and blooming, and methods for correcting these defects in pilchard oil are also discussed.
The Food of Salmon Fry in Eastern Canada
Authors: White H. C. 
Published: April 2011

Stomach analyses were made of young salmon in their first summer, as obtained from West and East Apple rivers, and Reeds and Eatonville creeks, all in Cumberland county, Nova Scotia, and from Digdeguash river in New Brunswick. Chironomid larvae formed the chief food of the newly emerged fry, while ephemerid nymphs constituted the major food taken during the mid-summer growing period. Trichoptera tended to become important toward autumn, but at times formed a considerable proportion of the food even in July and August. Plecoptera, simuliids and tipulids also occurred, and terrestrial forms such as Hymenoptera, Homoptera and Diptera were taken in appreciable quantities in late summer and autumn.
The Food and the Food Supply of Sockeye Salmon (Oncorhynchus nerka Walbaum) in Cultus lake, British Columbia.
Authors: Ricker William E. 
Published: April 2011

The analysis of several hundred stomachs of sockeye salmon taken from Cultus lake at all seasons shows that pelagic plankton crustaceans are practically the only food of the fingerlings, and are the most important food of the older fish. The total food consumed by fingerlings, per unit bulk, is greatest in July and August, least in winter. The entomostracan food available in the lake, as determined from plankton samples, varies seasonally in a similar manner. The percentage utilization of each of the four species of Entomostraca by a fingerling sockeye population is related directly to the plankter's abundance, and inversely to its size. Individual sockeye, however, occasionally exhibit preference for smaller or less abundant species. The summer feeding of fingerlings appears to be chiefly confined to the region between 5 and 15 metres depth, which includes the thermocline and adjacent narrow strips of the epilimnion and hypolimnion. Foraging is limited upward by scarcity of food, and downward by poor illumination or low temperature. Other fish in the lake are known to compete with sockeye for plankton, but such interspecific competition is believed to be quantitatively of minor importance, in summer at least. Intraspecific competition for food in years of large sockeye populations is sufficient to reduce their rate of growth, and is probably responsible for an unusually early decline, in those years, of the summer's supply of Entomostraca.
Cloning and characterization of an extremely conserved satellite DNA family from the root-knot nematode Meloidogyne arenaria
Authors: Castagnone-Sereno Philippe , Leroy Frédéric , Abad Pierre 
Published: April 2011

A new satellite DNA family, named pMaE, has been cloned from the genome of the phytoparasitic nematode, Meloidogyne arenaria (Nematoda: Tylenchida). It is represented as tandemly repeated sequences with a monomeric unit of 172 bp. The monomers are present at approximately 15 700 copies per haploid genome, and represent about 5.3% of the total genomic DNA. Twenty-seven independent monomers have been cloned and sequenced. The deduced consensus sequence is 70.9% A + T rich, with frequent stretches of A and (or) T. Several direct or inverted sub-repeats are present in the sequence, which may allow the formation of a dyad structure, suggesting some potential role of this repetitive sequence in heterochromatin condensation. The monomers are very homogeneous in sequence, showing on average 1.8% divergence from their consensus sequence. Moreover, Southern blot experiments and sequence analysis of homologous monomers from the genome of geographically distinct M. arenaria populations have shown that this satellite DNA is uniformly distributed and highly conserved within the species. Therefore, it is hypothesized that this unusually low level of variability, either within the genome of a given population or between populations, could be achieved as the result of some highly effective homogenization mechanism acting upon the nematode genome. Key words: genomic organization, Meloidogyne arenaria, satellite DNA.
Heterosis and genetic distance in rapeseed (Brassica napus L.): use of kinship coefficient
Authors: Lefort-Buson M. , Dattee Y. , Guillot-Lemoine B. 
Published: April 2011

Different agronomic characters have been measured on F1 rapeseeds from inbred lines that are more or less related and on their parents, in Rennes (France). Two different experiments were conducted over a 2-year period. A study of the relationship between heterosis and genetic distance, measured here by a function of kinship coefficient (1–ψ), was carried out in two steps. First, four classes of increasing 1–ψ values were defined and related to heterosis value and F1 performance. The results point out a significant effect of the class, whatever the character and the year. Moreover, the best heterotic hybrids were always obtained with lines unrelated and coming from two different geographic pools. Then, the efficiency of 1–ψ for predicting heterosis or cross values was tested: it varies with year and character. For example, in the first experiment average relationship between lines was high, about 50% of seed yield variation owing to mean parent heterosis was explained with the 1–ψ distance. Key words: heterosis, cross prediction, genetic distance, kinship coefficient, Brassica napus L.
Linkage studies in Tribolium castaneum (Herbst). XII. A revision of linkage group II
Authors: Sokoloff Alexander , Ferrone Robert F. , Chaney John D. , Braden Jerry , Muñoz Ricardo J. 
Published: April 2011

Data are presented to show the linkage relationships of a number of genes in linkage group II of Tribolium castaneum and a revised map of this linkage group is presented bearing eight well-established points. Some of these points were establishable with the aid of an accidental inversion induced by gamma irradiation. Five additional mutants are also in this linkage group as a result of the revision, but their relative position needs to be established through additional linkage studies. The linkage map suggests the presence of two gene clusters, one affecting the eye color and morphology and the other including homeotic mutants that affect the morphology of the maxillary and labial palps, the thorax, and the abdominal sternites. Data are presented to show that the frequency of recombination for a number of segments in linkage group II is not equal in the two sexes. The literature bearing on the evolution of the karyotype in Tribolium is reviewed, and it is concluded, on the basis of the present evidence, that it is linkage group II and not linkage group IX that became translocated to the X and Y chromosome in a T. castaneum like ancestor to produce the much larger neo-X and neo-Y chromosomes of T. confusum. Key words: Tribolium, linkage, gamma irradiation.
Cytogenetic study of three closely related species of Hawaiian Drosophila
Authors: Ahearn Jayne N. , Baimai Visut 
Published: April 2011

Three allopatric species from the Hawaiian islands, Drosophila bostrycha (Molokai), D. affinidisjuncta (West Maui), and D. disjuncta (East Maui), are extremely similar in morphology but differ in metaphase chromosomes by the amount and distribution of heterochromatin. Their polytene chromosomes are virtually homosequential with only slight differences at the tip of the microchromosome. Each is polymorphic for one or more inversions, especially in chromsome 4. Salivary gland chromosomes of F1 larvae reared either from wild-caught females or wild-caught males mated to standard laboratory stocks were examined for gene arrangements. Drosophila bostrycha and D. affinidisjuncta share a polymorphism for inversion 4v, which is much more frequent in the latter than in the former. In D. disjuncta 4v has been found only joined in a haplotype with three other inversions (g2 h2 i2) at a low frequency at Kipahulu Valley. Drosophila disjuncta is unique in having another fourth chromosome inversion, 4k, which is highest in frequency at Waikamoi. A new inversion, 2s, was discovered at Uluini Stream. Interspecific hybridizations were carried out in small mass matings. Backcrosses and dissections demonstrated that all F1 females were fertile. All F1 males were sterile in either of two categories with reciprocal hybrids uniformly manifesting one or the other type. Attempts to model the sterility mechanism suggest that more than chromosomal sterility is involved. Our results are discussed in relation to other closely related clusters of species having heterochromatin-based karyotype variations. Key words: heterochromatin, hybrid sterility, inversion, polymorphism, species divergence.
An autotetraploid model for genetic analysis of ozone tolerance in potato, Solanum tuberosum L.
Authors: Dragoescu N. , Hill Jr. R. R. , Pell E. J. 
Published: April 2011

A genetic model for the analysis of descendants of two autotetraploid parents was developed and applied to genetic analysis of ozone tolerance in the potato (Solanum tuberosum L.). The model was developed for two alleles with chromosome segregation at a single locus and contained 13 parameters. Assumptions about the genotype of the parents were not required. A multiple regression approach was used to derive sums of squares associated with the different parameters. Additive genetic effects for ozone resistance were more important than nonadditive genetic effects in the descendants of two sets of crosses. Deviations from the genetic model were not significant in either cross. Digenic effects and parameters associated with a disequilibrium constant were the only other significant effects, but sums of squares owing to these effects were much smaller than those for additive effects. Generation means derived from the crosses indicated that part of the nonadditive effects may have been caused by inbreeding depression. An alternative model with only additive genetic effects and a parameter with the coefficient of inbreeding as the coefficient was evaluated. The alternative model did not fit the observed data as well as the original model. Key words: ozone tolerance, potato, Solanum.
Chromosomal sex determination in aphids controlled by juvenile hormone
Authors: Hales Dinah F. , Mittler Thomas E. 
Published: April 2011

Parthenogenetically reproducing aphids give birth to males in response to low temperatures and short photoperiods. Since female aphids are XX and males are XO, the apomictic production of male eggs requires the elimination of one of the X chromosomes. Our previous experiments had suggested that male eggs were produced when the concentration of juvenile hormone was low; we now confirm this by showing that the juvenile hormone analogue kinoprene prevents ovulation of male eggs in aphids whose corpus allatum has been destroyed by precocene. Juvenile hormone concentration thus influences the behaviour of the X chromosomes during the maturation division of the eggs, a high titre resulting in the retention of both X chromosomes and a low titre in the elimination of one of them. Key words: sex determination, aphids, juvenile hormone, precocene, parthenogenesis.
Chromosome pairing at five ploidy levels in Elymus trachycaulus
Authors: Aung Taing , Walton P. D. 
Published: April 2011

An autoallooctaploid (2n = 56) form of Elymus trachycaulus (Link) Gould ex Shinners (previously Agropyron trachycaulum (Link) Malte ex H. F. Lewis) was induced by treating allotetraploid shoots with 0.2% colchicine. Successive backcrossing to tetraploid pollen parents was successful and yielded five hexaploid (2n = 42), one pentaploid (2n = 35), and three hyperploid (2n = 31, 32, 33) plants. Metaphase I of the tetraploids was normal and 14 II chromosomes were observed, almost all of which were ring bivalents. Chromosome pairing in one octaploid, four hexploids, and one pentaploid were 4.38 IV + 0.65 III + 17.84 II + 0.85 I, 13.16 III + 0.84 II + 0.84 I, and 5.82 III + 8.18 II + 1.18 I, respectively. Efficiency of chromsome pairing (chiasmata per chromsome) was highest in tetraploids (1.29), lowest in hexaploids (0.75), and intermediate in both octaploid (0.95) and pentaploid (0.93) plants. The octaploid produced longer and broader leaves than the tetraploid, although the total dry matter produced was 14.3% lower. Total dry matter yield of the hexaploid was on an average 30.04% higher than the tetraploid and the leaves were significantly larger. The hexaploid plants were taller than both the tetraploid and the octaploid plants. Metaphase I pairing in hyperploid 1 (2n = 33) was 4.34 III + 9.66 II + 0.66 I, hyperploid 2 (2n = 32) was 2.98 III 11.03 II + 1.00 I; hyperploid 3 (2n = 30 + 1 t) was 1.97 III + 12.05 II + 0.66 I + 0.33 t. The pattern of chromosome pairing in these hyperploids suggest that they are a quintupal trisomic, a quadrupal trisomic, and a triple trisomic respectively. Backcrossing these hyperploids to euploid pollen parents was successful. Backosses and their progeny should result in a series of primary trisomiclines and some monosomic plants, which would be useful for gene mapping. Key words: octaploid, hexaploid (double triploid), pentaploid, tetraploid, hyperploid, trisomic monosomic, Agropyron.