bluuebunny/crossref_metadata_2025 huggingface dataset:
Polar bear milk. IV. Gross composition, fatty acid, and mineral constitution
Authors: Cook H. W. , Lentfer J. W. , Pearson A. M. , Baker B. E.
Published: August 2008

Milk was obtained from two polar bears which were caught near Barrow, Alaska, and from one grizzly bear which was caught near Haines Junction, Yukon. The gross composition and the mineral and fatty acid constitution of the polar bear milk were determined. The fatty acid content of the grizzly bear milk was also determined.
Miconchus kansasensis n. sp. (Mononchidae: Nematoda) from Kansas, United States
Authors: Mulvey R. H. , Dickerson O. J.
Published: August 2008

A new species of predaceous nematode, Miconchus kansasensis is named and described. It differs from M. exilis (Cobb) in tail length and position of the vulva. Dimorphism in tail shape within the genus Miconchus is discussed. A taxonomic key to the species is provided.
A study of Canada geese, Branta canadensis, nesting on islands in southeastern Alberta
Authors: Vermeer Kees
Published: August 2008

Canada goose clutches situated on islands in Dowling Lake and Lake Newell, Alberta, were checked from laying to hatching. Egg-laying intervals averaged 1.87 days and incubation periods 26.8 days. The distribution of nests showed a significant deviation from randomness in the direction of uniform spacing. Causes of extensive hatching failure at Dowling Lake were predation and desertion. Predation by coyotes was facilitated by low water levels. A preference for nesting on islands appears to be a mechanism to counteract mammalian predation.
Genus Ottolenchus n. rank and Ottolenchus sulcus n. sp. (Tylenchidae: Nematoda)
Authors: Wu Liang-Yu
Published: August 2008

Subgenus Tylenchus (Ottolenchus) Husain and Khan, 1967 is raised to the generic rank, Ottolenchus, to accommodate three species: Ottolenchus equisetus (Husain and Khan, 1967) n. comb.; Ottolenchus fusiformis (Thome and Malek, 1968) n. comb.; Ottolenchus sulcus n. sp.
Strontium-90 and cesium-137 levels in tissues of fin whale (Balaenoptera physalus) and harp seal (Pagophilus groenlandicus)
Authors: Samuels E. R. , Cawthorn M. , Lauer B. H. , Baker B. E.
Published: August 2008

90Sr and 137Cs were determined in 11 different tissues of the fin whale and 2 different tissues of the harp seal. Muscle tissue in most instances contained more 137Cs than did the other tissues that were examined. The average concentration of 137Cs in whale muscle was 4.5 pCi/g ash and in adult seal muscle was 2.5 pCi/g ash. The highest concentration (3.5 pCi/g ash) of 90Sr was found in whale blubber.
Differential white blood cell counts for the urodele Taricha granulosa
Authors: Friedmann G. B.
Published: August 2008

Red, white, and differential cell counts for blood from the heart and from the tail of 13 non-hibernating adult Taricha granulosa are presented.
Observations on the behavior and larval development of Acanthomysis sculpta (Tattersall), (Mysidacea)
Authors: Green John M.
Published: August 2008

Observations on the behavior and larval development of A. sculpta collected from a surge channel at Botanical Beach, Vancouver Island, British Columbia, were made from 12 to 25 August, 1965. Larvae-bearing females were kept in compartmented plastic trays and larvae from their brood pouches were periodically removed and preserved. Development from hatching to liberation from the brood pouch takes about 5 days at about 12 °C. Apparently, the young are liberated from the brood pouch only at night. The nocturnal emergence of the young is considered to be important to their survival in that it helps prevent them from being eaten by larger specimens.
Haemolymph protein metabolism during the fifth instar of Locusta
Authors: Tobe S. S. , Loughton B. G.
Published: August 2008

Selected blood proteins were studied during the fifth instar of Locusta by means of acrylamide 'disc electrophoresis' after injection of 3H-labeled blood proteins or 3H-leucine. Label was found to accumulate in the "common protein" fraction in the middle of the instar after injection of labeled blood protein. The specific activity of the other blood proteins studied followed the pattern predicted by their concentration changes. The specific activity of blood proteins after injection of 3H-leucine was generally high during the early part of the instar and fell after 152 h. Most activity was found in the "common protein." A program of protein metabolism for the fifth-instar locust is suggested on the basis of these and earlier results.
The temperature selection of small hypophysectomized goldfish (Carassius auratus L.)
Authors: Roy A. W. , Johansen P. H.
Published: August 2008

The selected temperature ranges of unoperated, sham-operated, and hypophysectomized goldfish were determined in a horizontal temperature gradient. Hypophysectomy did not alter the selected temperature of small goldfish.
The commensal association of Calliactis polypus and the hermit crab Dardanus gemmatus in Hawaii
Authors: Ross D. M.
Published: August 2008

Calliactis polypus (Forskål) lives as a commensal with various pagurids in the Pacific and Indian Oceans. In trials with the Hawaiian species, Dardanus gemmatus, the anemone, unlike the European C. parasitica, displayed only slight activity towards crabs or molluscan shells. As reported previously, crabs display a highly active behavior pattern towards C. polypus, tapping and scratching the column and eventually transferring it to its shell. The mechanical stimuli applied by the crab cause C. polypus to relax so completely that it can be lifted easily off the surface to which it was attached. Unlike C. parasitica and C. tricolor under similar circumstances, C. polypus does not release its pedal disc unaided. The tentacles and pedal disc of the detached C. polypus are extremely sticky and adhere at once to any solid surface presented to them. This enables an anemone detached by a crab to settle quickly on the shell even when only a small area of the pedal disc or only a few tentacles come into contact with the shell when placed there by the crab. The discussion emphasizes these differences in the behavior of closely related species in achieving the same ends. It also stresses that C. polypus, possessing a relatively simple nervous system, displays an impressive repertoire of responses to specific stimuli in its association with its pagurid host.
The harp seal, Pagophilus groenlandicus (Erxleben, 1777). VI. Structure of retina
Authors: Nagy A. R. , Ronald K.
Published: August 2008

The retina of the harp seal (Pagophilus groenlandicus) was studied by means of the light microscope. Ganglion cells occupy a single layer. Thinly dispersed throughout this layer are giant ganglion cells. There is no area centralis. The inner nuclear layer consists of large horizontal cell processes with bipolar and amacrine cells between the horizontal cell processes. The outer nuclear layer is the thickest of all retinal layers. Its density is constant in the central and peripheral areas of the retina, similar to that found in the inner nuclear and ganglion layers. Only rod photoreceptors were found; therefore it is presumed that seals have no color vision. The tapetum covers an extensive area and is 32–34 cellular layers thick centrally, diminishing in thickness peripherally. The combination of tapetum and rod receptors makes possible excellent visual sensitivity to dim light.
Maintaining mosquito colonies of Aedes atropalpus and Anopheles stephensi with less than 5 hours labor per month
Authors: French Frank E.
Published: August 2008

By the tank method a small colony of A. atropalpus has been maintained for more than 2 years with an average of 2 h labor per month. The rearing unit consists of a water tank, connected cage, low-volume air supply, and food. The adult population ranged from 25 to 100; larvae 25–200; no mosquitoes were added. Larval population was adjusted by adding water to the tank, thus hatching eggs above the water line. A requirement to expand the colony was met by adding water until the tank was completely filled. About 500 larvae hatched, were siphoned out, and transferred to facilities to meet the increased requirements for adult mosquitoes.A similar unit was used for A. stephensi and has operated successfully for 15 months. Blood-feeding makes the total labor about 5 h per month for A. stephensi.
Habitat co-occupancy among some vireos of the subgenus Vireo (Aves: Vireonidae)
Authors: Barlow Jon C. , James Ross D. , Williams Nikki
Published: August 2008

Habitat co-occupancy is reported for the first time between the gray vireo (Vireo vicinior Coues) and the Bell vireo (V. belli arizonae Ridgeway) and the former species and the solitary vireo (V. solitarius plumbeus Coues). Observations were made in central and northern Arizona. Behavioral and vocal differences facilitate the association between V. vicinior and V. belli arizonae, but only behavioral differences are seemingly used by V. vicinior and V. solitarius plumbeus.
Gonadal hormone concentrations in northern phalaropes in relation to nuptial plumage
Authors: Höhn E. Otto
Published: August 2008

A sample of prebreeding season gonads of northern phalaropes showed a high ovarian ratio of testosterone/estradiol, and a greater concentration of testosterone in the ovaries than in the testes. These features correspond to those found in the gonads of Wilson's phalarope and differ from those found in the gonads of four other species of birds. In conjunction with the earlier demonstration that the nuptial plumage in this species is androgen-dependent, these facts explain the more colorful nuptial plumage of the female compared to that of the male northern phalarope.
Invertebrates from an abandoned muskrat bouse at London, Ontario
Authors: Judd William W.
Published: August 2008

On July 26, 1967, 158 organisms including earthworms, snails, slugs, sow bugs, spiders, and beetles in the families Carabidae, Staphylinidae, Hydrophilidae, and Helodidae were taken from an abandoned muskrat house at London, Ontario.
Ultrastructural study of the teguminal sheaths of two metastrongyloid nematodes
Authors: Stockdale P. H. G. , Fernando M. A. , Gilroy J.
Published: August 2008

The ultrastructure of the surface layers of two metastrongyloid nematodes, Crenosoma vulpis and Perostrongylus pridhami, is described. The cuticles of both worms consist of the three basic layers of a typical nematode cuticle: an outer cortex, a middle matrix, and an inner basal layer. The "teguminal sheath" described as an outer sheath in certain metastrongyloids appears to correspond to the cortex in both the nematodes studied. The very wide matrix of low-density material separating the outer cortex from the inner basal layer of the cuticle is thought to have led to the concept that the "teguminal sheath" is a loose membranous sheath enveloping the nematode.
The breeding season and reproductive cycle of the western red squirrel
Authors: Millar John S.
Published: August 2008

Breeding in the red squirrel, Tamiasciurus hudsonicus (Erxleben), in southern British Columbia differed in some respects from that reported in eastern North America. The period during which males were capable of breeding varied from 2 to 6 months, and their reproductive organs showed only a single peak in size each year. All breeding females produced two litters in 1966, but only one litter in 1967. Females did not breed during the year of their birth, and, in 1967, some did not breed as yearlings. February appeared to be the earliest date for the onset of breeding in southern British Columbia. The timing of breeding may be influenced by weather conditions.
Some observations on ion and water balance in the puffin, Fratercula arctica
Authors: Hughes Maryanne Robinson
Published: August 2008

The mean values for six adult puffins were hematocrit, 0.511 ± 0.007; plasma sodium, 160.7 ± 2.3, potassium, 3.1 ± 0.1, and chloride, 133.4 ± 1.9 meq/l.The cloacal fluid of one young laboratory-reared puffin was always hypotonic to the plasma in Na and Cl and never contained more than one-half the ingested Na, K, or Cl; contained less than 40% of the ingested water; and solid material was less than 10% of the total as determined by dry weight.In one salt load experiment (4.0 ml 1.0 N NaCl/3 92-gram adult) the salt glands proved very efficient, producing a secretion of 975 meq/l (maximum) Cl and eliminating 75% of the load in 20 min. The salt glands and kidneys are large, 0.1% and 1.8% of the body weight respectively.
The effects of nutrient and non-nutrient diets on the fat body cell nuclei and nucleoli of starved nymphs of Rhodnius prolixus (Hemiptera)
Authors: Millen B. H. , Beckel W. E.
Published: August 2008

Fourth-instar nymphs of Rhodnius prolixus were starved for 23 weeks and then gorged on nutrient (blood) or non-nutrient (saline with dextran) diet. Light microscopy was used to examine changes occurring in the nuclei and nucleoli of the fat body cells for 5 days after feeding.In starved nymphs, all features of the nuclei and nucleoli indicate functional inactivity. Two types of chromatin granules can be distinguished. In a given nucleus, one type appears to be exclusive.Blood feeding causes changes in the nuclei and nucleoli manifesting cell activation, i.e. restoration of the cell's capacity for protein synthesis. The activation criteria noted were: enlargement of the nuclei and nucleoli; accumulation of ribonucleic acid (RNA) by the nucleoli; alteration of chromatin granule structure; dispersion of Fused chromatin granules from about the nucleoli; elaboration of the intra-nucleolar chromatin within the nucleolus; and contortion of the shape of the nucleolus.Saline with dextran feeding does not cause cell activation. Instead, the cells undergo accelerated wastage as reflected by degenerative changes in the nuclei (pyknosis) and nucleoli.
Effects of prolactin on the epidermal mucous cells of the goldfish, Carassius auratus L.
Authors: Ogawa Mizuho
Published: August 2008

In hypophysectomized goldfish, prolactin injections caused an increase in both number and size of the epidermal mucous cells. In contrast, the effects of prolactin injections in intact fish varied seasonally; in summer the growth and new formation of mucous cells were slightly inhibited; in the late autumn, however, the mucous cells of prolactin-injected intact goldfish increased slightly in size but there was no significant change in cell number.The action of prolactin on the mucous cells of goldfish has been discussed and the possibility of a seasonal variation of prolactin secretion considered.
Termination of the hypopial stage in Caloglyphus mycophagus (Mégnin) (Acarina: Acaridae)
Authors: Kuo J. S. , Nesbitt H. H. J.
Published: August 2008

Termination of the hypopial stage of Caloglyphus mycophagus and transformation to a normal tritonymph is accomplished by a molt. The split produced by this molt occurs on the posterior end of the body. Combinations of temperature, relative humidity, and nutrition regulate hypopial termination. Hypopi can molt only at 15 °C or above. The higher the temperature, the more hypopi transform. Higher relative humidity also may aid termination. More hypopi molt from mites raised on medium of animal origin than of plant origin. Hypopial duration may also be influenced by environmental factors. Higher temperature and media of animal origin result in a shorter hypopial duration.
Colonization of islands by ecologically dissimilar species of mammals
Authors: Grant P. R.
Published: August 2008

A theory of competitive interaction predicts that ecologically dissimilar species of animals within a taxon occur together on islands more frequently than do ecologically similar species. The theory was tested with rodents of the genera Microtus, Clethrionomys, Peromyscus, and Apodemus. Based upon information derived from mainland studies, the prediction was made that Microtus and Clethrionomys, deemed to be the most similar pair ecologically, occur together on islands rarely. Data from three groups of islands showed the prediction to be correct. These two genera do not occur together on any of the islands examined which support only two genera. Other factors which might govern the observed distributions, including the dispersal abilities of the genera, are discussed. It is suggested that there is a trend in the occupation of islands from ecological generalists to specialists.
Effect of temperature on a greenhouse acarine predator–prey population
Authors: Burnett T.
Published: August 2008

Populations of the two-spotted mite, Tetranychus urticae, and its acarine predator, Amblyseius fallacis, were propagated on alfalfa in the greenhouse at constant temperatures in the range 65 to 85 °F (18.3–29.4 °C). The predator limited the initial increase in prey abundance only at temperatures above about 70 °F (21.1 °C). At 80 and 85 °F (26.7 and 29.4 °C) fluctuations in prey and predator numbers increased in amplitude as propagation continued. The age structure of the predator population reared at 75 °F (23.9 °C) differed from that of populations propagated at the other temperatures.
Simple techniques for making avian blood smears
Authors: Bennett Gordon F.
Published: August 2008

Simple equipment and techniques for improving the quality of avian blood smears obtained in field surveys are described.
Note on the escape response of the sea urchin, Strongylocentrotus dröbachiensis, to inorganic salts
Authors: Chia Fu-Shiang
Published: August 2008

A number of inorganic salts at dilute solutions can evoke an escape response of the regular sea urchin Strongylocentrotus dröbachiensis upon the application to a small area of the animal. This behavior is similar to that caused by the stimulus from a predatory starfish, Marthasterias glacialis.
Effectiveness of KC1 and NaCl injections in arousing 13-lined ground squirrels from hibernation
Authors: Fisher K. C. , Mrosovsky N.
Published: August 2008

Injections of relatively concentrated solutions of KC1 were more effective in arousing 13-lined ground squirrels from hibernation than injections of NaCl solutions of equal osmolarity. The result supports the theory that metabolic end products trigger arousals.
Metazoan parasites of the American eel (Anguilla rostrata (LeSueur)) in Newfoundland and Labrador
Authors: Hanek George , Threlfall William
Published: August 2008

Sixty American eels from six localities in Newfoundland and Labrador were examined for metazoan parasites during the period June, 1967–July, 1969. Fifty-eight percent were found to be infected with digenetic trematodes (three genera), cestodes (two genera), nematodes (two genera), acanthocephalans (two genera) and copepods (one genus).
Periodicities in the thick filaments of the opaque and translucent parts of the adductor of the oyster, Crassostrea virginica
Authors: Morrison C. M. , Cameron M. L. , Odense P. H.
Published: August 2008

The opaque and translucent parts of the adductor muscle of Crassostrea virginica were studied. A transverse periodicity was found in the thick filaments from both types of muscle, and a diagonal periodicity was also found in the thick filaments from the opaque muscle. The thick filaments of the opaque muscle had transverse periods of 56 Å and diagonal periods of 334 Å. Since the diagonal periodicity occurs only in smooth muscle, it may represent a structure associated with the catch mechanism.
Water mites (Hydracarina) as predators of chironomid larvae (Insectar: Diptera)
Authors: Paterson C. G.
Published: August 2008

Adults of two species of water mites, Piona carnea (Koch) and Limnesia undulata (Muller), readily preyed upon a number of species of chironomid larvae under laboratory conditions. The observed rate of feeding and the inability of the water mites to withstand prolonged periods of starvation suggest that they are significant predators of chironomid larvae in the natural environment.
Addendum: New Enchytraeidae (Oligochaeta) from the east coast of Vancouver Island
Authors: Tynen Michael J.
Published: August 2008

Species of Enchytraeidae (Oligochaeta) described in Can. J. Zool. 47: 387–393 are designated as type specimens and listed with their National Museum of Canada catalogue numbers. Lumbricillus kamtschatkanus Michaelsen 1929 is added to the number of Lumbricillus spp. described from the north Pacific.
Dall sheep (Ovis dalli dalli) milk. I. Effects of stage of lactation on the composition of the milk
Authors: Cook H. W. , Pearson A. M. , Simmons N. M. , Baker B. E.
Published: August 2008

Milk was collected from nine dall sheep which were killed either in the Yukon or the Northwest Territories. The stage of lactation of the animals ranged from 10 days prepartum to 24 weeks postpartum. The gross composition and the fatty acid and the mineral constitution of the dall sheep milk were determined.
The fine structure of Leucocytozoon simondi. III. The ookinete and mature sporozoite
Authors: Desser Sherwin S.
Published: August 2008

The pellicles of ookinetes and sporozoites of Leucocytozoon simondi measure about 40 mμ and are similar in appearance. The parasites are bounded externally by a trilaminar plasma membrane beneath which lies a fibrillar zone. Below this zone and forming the inner surface of the pellicle is a second membrane-like layer. The specialized apical region of the ookinete is modified into a thickened "cap-like" structure. The pellicle in this apical cap region appears wavy and the inner layer appears allernately thick and thin in transverse section. In the subpellicular space lie numerous long thickened structures suggestive of struts which line the inner surface of the apical cap. Beneath these, about 70 microtubules ring the cytoplasm. Numerous dense elongate micronemes extend anteriorly toward the apex of the ookinete. The anterior tip of the pellicle of sporozoites is modified into a cup-like conoid and a polar ring with which about 35 subpellicular microtubules are associated. Elongate paired organelles extend anteriorly from the nuclear region to the polar ring. Numerous dense, ellipsoidal granules and one or more mitochondria are seen in the cytoplasm. A crystalline material which corresponds with the "vacuoles" observed in Giemsa-stained ookinetes and sporozoites lies in two or more zones within the cytoplasm and may be a stored food material or possibly a virus.
The biology of Gammarus (Crustacea, Amphipoda) in the northwestern Atlantic. II. Gammarus setosus Dementieva
Authors: Steele V. J. , Steele D. H.
Published: August 2008

Gammarus setosus is a circumpolar species found as far south as the Bay of Fundy region in the northwest Atlantic. Under laboratory conditions (3 °C) sexual maturity is reached in the 13th molt, at 14 mm in the males and at 12 mm in the females. In the field 50%, maturity is attained at 13.5 mm in the females. Mature females annually produce a single autumn brood, which is released in late winter or early spring. They then enter an obligatory resting period. In the laboratory at 12 °C they can have more than one brood annually. Fecundity increases with the size of the Female. The large size at maturity, continued growth, and long life with resulting high fecundity partially compensate for the production of but one brood per year.
An analysis of character variation in red-eyed and Philadelphia vireos (Aves: Vireonidae) in Canada
Authors: Barlow Jon C. , Power Dennis M.
Published: August 2008

Red-eyed and Philadelphia vireos are broadly sympatric and occasionally syntopic across Canada. Collections were made at seven localities in a transect from central Alberta to central Quebec and measurements taken on six morphological characters. Analysis of variance located significant differences among locality samples for bill length, bill depth, and tarsus length in the red-eyed vireo, and for bill depth, wing length, tail length, and tarsus length in the Philadelphia vireo. A posteriori analysis of variance determined subsets of localities that did not differ significantly, and demonstrated discordant variation in most characters. In red-eyed vireos a positive regression of bill length and width on mean and minimum temperatures of collecting localities suggested variation in accordance with Allen's rule. In the Philadelphia vireo regression analyses showed an increase in tarsus length with a decrease in temperature and precipitation, the temperature effect being the opposite of variation predicted by Allen's rule. Multivariate analysis of variance further demonstrated significant phenetic differences among samples of both species. Projection of locality means and confidence regions onto first and second canonical axes showed that for the red-eyed vireo, with the exception of one sample, localities in proximity geographically tend to be in proximity in the character space. This was not true for the Philadelphia vireo in which selection for variation in the characters may be predominantly off the breeding grounds.
Evidence for a memory process in the turning behavior of free swimming goldfish
Authors: Westlake G. F. , Kleerekoper H.
Published: August 2008

Positive correlation was established between the magnitudes of consecutive turns in opposite directions of naive goldfish in a monitor tank. Evidence is presented for a decrease in this correlation with increasing time between turns; no change in correlation could be established with distance between turns. Results are discussed with reference to the literature on spontaneous alternation and the possible effect of walls on this behavior.
Anatomy of the hind flippers of two species of seals with reference to thermoregulation
Authors: Tarasoff F. J. , Fisher H. Dean
Published: August 2008

The topography and vascular arrangements were examined in the hind flippers of representatives of two families of Pinnipedia: Otariidae, Callorhinus ursinus; and Phocidae, Phoca vitulina.Clearly defined topographical differences were evident between the two animals. However, extreme angiological differences were not evident, possibly because of common ancestry or of convergent adaptation to the marine habitat. The external features, and the arrangement and structure of the vascular network suggest a possible role in thermoregulation.
Reproductive dynamics of a turtle (Pseudemys scripta) population in a reservoir receiving heated effluent from a nuclear reactor
Authors: Gibbons J. Whitfield
Published: August 2008

Individual yellow-bellied turtles (Pseudemys scripta) in Par Pond, a thermally polluted reservoir on the Savannah River Plant, Aiken, South Carolina, U.S.A., reach exceedingly large body sizes and maintain extraordinary juvenile growth rates when compared with turtles of this species from other populations in the vicinity. Increased water temperatures are not directly responsible for the observed size and growth differences. Diet differences resulting from increased productivity at lower trophic levels as a result of the hot-water effluent may be the cause of the observed growth and size phenomena. The increased growth rates and larger body sizes in the Par Pond turtles result in changes in reproductive rate which may have interesting consequences on the demography of the population.
Amino acid compositions of normal and regenerated shell of Helix
Authors: Saleuddin A. S. M. , Hare P. E.
Published: August 2008

The amino acid compositions of the normal and the regenerated shell of Helix have been recorded by ion exchange chromatography. The regenerated shell is more related to the nacreous layer than to the outer layers of the normal shells so far as the amino acid compositions are concerned.
A new bleaching and decalcifying method for general use in zoology
Authors: Trpiš Milan
Published: August 2008

A new technique for clearing pigmented animal tissues and organs has been developed. Its advantages over existing techniques include a high bleaching effect without any deterioration of the treated objects. The bleaching can be combined with a decalcifying process if the tissues and organs contain calcium. This technique should find ready application in the bleaching of all kinds of pigmented animal organs.
Development of trypanosomes of the T. avium complex in the invertebrate host
Authors: Bennett Gordon F.
Published: August 2008

Development of strains of the Trypanosoma avium complex were studied in an experimental vector, Aedes aegypti. Developmental stages in the midgut and the rate of multiplication of the trypanosomes in mosquitoes held at different temperatures are described. Some factors influencing the multiplication of T. avium in the invertebrate host are discussed and observations on the development of the flagellates in simuliids, ceratopoginids, and tabanids are presented.
Stereoscan views of some aphid mouthparts
Authors: Adams Jean B. , Fyfe Forest W.
Published: August 2008

The mouthparts, particularly the probosces of two aphid species, Myzus persicae (Sulzer) and Macrosiphum euphorbiae (Thomas), are compared with the use of the scanning electron microscope. The details of the setae on the terminal segments of the winged and wingless morphs are compared.
Reversal of malathion-induced teratisms and its biochemical implications in the developing chick
Authors: Greenberg J. , LaHam Q. N.
Published: August 2008

Malathion-induced teratisms in the chick embryo included hind limb, beak, and feather defects as well as overall growth retardation. Various metabolites were injected along with malathion into fertile eggs in an attempt to determine the possible effect of the latter compound on metabolism. Of those compounds injected tryptophan prevented both the malformations and the growth retardation while nicotinamide, nicotinic acid, and quinolinic acid prevented the malformations only. Other compounds related to tryptophan by electronic reactivity enhanced the effect of malathion. A cholinesterase assay on embryo homogenates revealed no relationship between cholinesterase levels and teratisms.
A histological and histochemical study of the development of the amnioallantois in the chick, Gallus domesticus
Authors: Kenny T. P. , Gibson M. A.
Published: August 2008

The amnioallantoic membrane is composed of four layers. (1) An inner amnionic epithelium which is a stratified layer during most of the incubation period. This layer stains positively for glycogen, ribonucleic acid, and neutral and acidic lipids and appears to be most active during the 15 to 17 days of incubation period. (2) A muscle layer composed of dorsoventrally and anteroposteriorly directed bands. During the early incubation stages these bands are organized to form the muscle configurations known as "cross-figures." During the later incubation stages, the organization of these muscle layers is disrupted by invasions of connective tissue and fat. (3) A connective tissue layer which includes blood and lymphatic vessels. (4) An outer allantoic epithelium which is rich in secretory granules. These granules include a sulfated mucopolysaccharide component. The activity of the allantoic epithelium increases progressively during the incubation period and is at peak activity at the 17- to 19-day incubation stage. During the final stages of incubation all layers show signs of decreased activity and degeneration.
INFLUENCE OF DEMOGRAPHIC VARIABLES ON INDIRECT TAX SETTING FOR SELECTED INDIAN STATES
Authors: SETH A. K. , BHATNAGAR ANKUR
Published: August 2008

This paper attempts to provide conclusive evidence in favor of sensitivity of optimal commodity taxes to demographic variables. This involves estimating optimal commodity taxes for the chosen 16 Indian states, incorporating demographic profiles for each state using NSS data. Such calculations are further done under alternative welfare weights for each household. The results reveal that the introduction of demographic variables in the demand system makes the tax rates more non-uniform across commodities and across states, and significantly alters their response to changes in the social planner's perception of a household's welfare. These effects are more pronounced for certain commodities that are basic and essential in a household's basket. Differences in welfare weights also have a similar effect on tax rates, though to a lesser degree.
HEAVY BARYONS IN A QUARK MODEL
Authors: ROBERTS W. , PERVIN MUSLEMA
Published: August 2008

A quark model is applied to the spectrum of baryons containing heavy quarks. The model gives masses for the known heavy baryons that are in agreement with experiment, but for the doubly-charmed baryon Ξcc, the model prediction is too heavy. Mixing between the ΞQ and Ξ′Q states is examined and is found to be small for the lowest lying states. In contrast with this, mixing between the Ξbc and Ξ′bc states is found to be large, and the implication of this mixing for properties of these states is briefly discussed. We also examine heavy-quark spin-symmetry multiplets, and find that many states in the model can be placed in such multiplets. We compare our predictions with those of a number of other authors.
HIGH-ENERGY ATMOSPHERIC MUON FLUX EXPECTED AT INDIA-BASED NEUTRINO OBSERVATORY
Authors: PANDA SUKANTA , SINEGOVSKY SERGEI I.
Published: August 2008

We calculate the zenith-angle dependence of conventional and prompt high-energy muon fluxes at India-Based Neutrino Observatory (INO) depth. This study demonstrates a possibility to discriminate models of the charm hadroproduction including the low-x QCD behavior of hadronic cross-sections relevant at very high energies.
STRONG S-EQUIVALENCE OF ORDERED LINKS
Authors: GEE CAROL GWOSDZ
Published: August 2008

In 2003, Naik and Stanford proved that two S-equivalent knots are related by a finite sequence of doubled-delta moves on their knot diagrams. We show that classical S-equivalence is not sufficient to extend their result to ordered links. We define a new algebraic relation on Seifert matrices, called strong S-equivalence, and prove that two oriented, ordered links L and L′ are related by a sequence of doubled-delta moves if and only if they are strongly S-equivalent. We also show that this is equivalent to the fact that L′ can be obtained from L through a sequence of Y-clasper surgeries, where each clasper leaf has total linking number zero with L.
RATIONAL BLOW-DOWNS IN HEEGAARD–FLOER HOMOLOGY
Authors: ROBERTS LAWRENCE P.
Published: August 2008

We examine the effect rational blow-downs have on the Ozsváth–Szabó, four-manifold invariant, verify that it is identical to that on the Seiberg–Witten invariants, and extend to new classes of blow-downs.
Hard Java
Authors: Frenger Paul
Published: August 2008

Sun Microsystems has been a fantastic repository of talent for years, somewhat reminiscent of Apple Computer and the Xerox PARC (Palo Alto Research Center). Sun developed the SPARC line of CPUs for their Solaris Operating System (a flavor of Unix). This group devised the only-ever hardware- and software-independent computer boot-up system (OpenBoot / Open Firmware / IEEE 1275). They also brought forth Java, a programming language which today seems ubiquitous and indispensable.
Single global lock semantics in a weakly atomic STM
Authors: Menon Vijay , Balensiefer Steven , Shpeisman Tatiana , Adl-Tabatabai Ali-Reza , Hudson Richard L. , Saha Bratin , Welc Adam
Published: August 2008

As memory transactions have been proposed as a language-level replacement for locks, there is growing need for well-defined semantics. In contrast to database transactions, transaction memory (TM) semantics are complicated by the fact that programs may access the same memory locations both inside and outside transactions.
Strongly atomic
semantics, where non-transactional accesses are treated as implicit single-operation transactions, remain difficult to provide without specialized hardware support and/or significant performance overhead. As an alternative, many in the community have informally proposed that a
single global lock semantics
[16, 9], where transaction semantics are mapped to those of regions protected by a single global lock, provide an intuitive and efficiently implementable model for programmers.

In this paper, we explore the implementation and performance implications of single global lock semantics in a weakly atomic STM from the perspective of Java, and we discuss why even recent STM implementations fall short of these semantics. We describe a new weakly atomic Java STM implementation that provides single global lock semantics while permitting concurrent execution, but we show that this comes at a significant performance cost. We also propose and implement various alternative semantics that loosen single lock requirements while still providing strong guarantees. We compare our new implementations to previous ones, including a strongly atomic STM. [22]
Path splicing
Authors: Motiwala Murtaza , Elmore Megan , Feamster Nick , Vempala Santosh
Published: August 2008

We present path splicing, a new routing primitive that allows network paths to be constructed by combining multiple routing trees ("slices") to each destination over a single network topology. Path splicing allows traffic to switch trees at any hop en route to the destination. End systems can change the path on which traffic is forwarded by changing a small number of additional bits in the packet header. We evaluate path splicing for intradomain routing using slices generated from perturbed link weights and find that splicing achieves reliability that approaches the best possible using a small number of slices, for only a small increase in latency and no adverse effects on traffic in the network. In the case of interdomain routing, where splicing derives multiple trees from edges in alternate backup routes, path splicing achieves near-optimal reliability and can provide significant benefits even when only a fraction of ASes deploy it. We also describe several other applications of path splicing, as well as various possible deployment paths.
A policy-aware switching layer for data centers
Authors: Joseph Dilip A. , Tavakoli Arsalan , Stoica Ion
Published: August 2008

Data centers deploy a variety of middleboxes (e.g., firewalls, load balancers and SSL offloaders) to protect, manage and improve the performance of applications and services they run. Since existing networks provide limited support for middleboxes, administrators typically overload path selection mechanisms to coerce traffic through the desired sequences of middleboxes placed on the network path. These ad-hoc practices result in a data center network that is hard to configure and maintain, wastes middlebox resources, and cannot guarantee middlebox traversal under network churn.

To address these issues, we propose the policy-aware switching layer or PLayer, a new layer-2 for data centers consisting of inter-connected policy-aware switches or pswitches. Unmodified middleboxes are placed off the network path by plugging them into pswitches. Based on policies specified by administrators, pswitches explicitly forward different types of traffic through different sequences of middleboxes. Experiments using our prototype software pswitches suggest that the PLayer is flexible, uses middleboxes efficiently, and guarantees correct middlebox traversal under churn.
A scalable, commodity data center network architecture
Authors: Al-Fares Mohammad , Loukissas Alexander , Vahdat Amin
Published: August 2008

Today's data centers may contain tens of thousands of computers with significant aggregate bandwidth requirements. The network architecture typically consists of a tree of routing and switching elements with progressively more specialized and expensive equipment moving up the network hierarchy. Unfortunately, even when deploying the highest-end IP switches/routers, resulting topologies may only support 50% of the aggregate bandwidth available at the edge of the network, while still incurring tremendous cost. Non-uniform bandwidth among data center nodes complicates application design and limits overall system performance.

In this paper, we show how to leverage largely commodity Ethernet switches to support the full aggregate bandwidth of clusters consisting of tens of thousands of elements. Similar to how clusters of commodity computers have largely replaced more specialized SMPs and MPPs, we argue that appropriately architected and interconnected commodity switches may deliver more performance at less cost than available from today's higher-end solutions. Our approach requires no modifications to the end host network interface, operating system, or applications; critically, it is fully backward compatible with Ethernet, IP, and TCP.
Dcell
Authors: Guo Chuanxiong , Wu Haitao , Tan Kun , Shi Lei , Zhang Yongguang , Lu Songwu
Published: August 2008

A fundamental challenge in data center networking is how to efficiently interconnect an exponentially increasing number of servers. This paper presents DCell, a novel network structure that has many desirable features for data center networking. DCell is a recursively defined structure, in which a high-level DCell is constructed from many low-level DCells and DCells at the same level are fully connected with one another. DCell scales doubly exponentially as the node degree increases. DCell is fault tolerant since it does not have single point of failure and its distributed fault-tolerant routing protocol performs near shortest-path routing even in the presence of severe link or node failures. DCell also provides higher network capacity than the traditional tree-based structure for various types of services. Furthermore, DCell can be incrementally expanded and a partial DCell provides the same appealing features. Results from theoretical analysis, simulations, and experiments show that DCell is a viable interconnection structure for data centers.
Answering what-if deployment and configuration questions with wise
Authors: Tariq Mukarram , Zeitoun Amgad , Valancius Vytautas , Feamster Nick , Ammar Mostafa
Published: August 2008

Designers of content distribution networks often need to determine how changes to infrastructure deployment and configuration affect service response times when they deploy a new data center, change ISP peering, or change the mapping of clients to servers. Today, the designers use coarse, back-of-the-envelope calculations, or costly field deployments; they need better ways to evaluate the effects of such hypothetical "what-if" questions before the actual deployments. This paper presents What-If Scenario Evaluator (WISE), a tool that predicts the effects of possible configuration and deployment changes in content distribution networks. WISE makes three contributions: (1) an algorithm that uses traces from existing deployments to learn causality among factors that affect service response-time distributions; (2) an algorithm that uses the learned causal structure to estimate a dataset that is representative of the hypothetical scenario that a designer may wish to evaluate, and uses these datasets to predict future response-time distributions; (3) a scenario specification language that allows a network designer to easily express hypothetical deployment scenarios without being cognizant of the dependencies between variables that affect service response times. Our evaluation, both in a controlled setting and in a real-world field deployment at a large, global CDN, shows that WISE can quickly and accurately predict service response-time distributions for many practical What-If scenarios.
A case for adapting channel width in wireless networks
Authors: Chandra Ranveer , Mahajan Ratul , Moscibroda Thomas , Raghavendra Ramya , Bahl Paramvir
Published: August 2008

We study a fundamental yet under-explored facet in wireless communication -- the width of the spectrum over which transmitters spread their signals, or the channel width. Through detailed measurements in controlled and live environments, and using only commodity 802.11 hardware, we first quantify the impact of channel width on throughput, range, and power consumption. Taken together, our findings make a strong case for wireless systems that adapt channel width. Such adaptation brings unique benefits. For instance, when the throughput required is low, moving to a narrower channel increases range and reduces power consumption; in fixed-width systems, these two quantities are always in conflict. We then present a channel width adaptation algorithm, called SampleWidth, for the base case of two communicating nodes. This algorithm is based on a simple search process that builds on top of existing techniques for adapting modulation. Per specified policy, it can maximize throughput or minimize power consumption. Evaluation using a prototype implementation shows that SampleWidth correctly identities the optimal width under a range of scenarios. In our experiments with mobility, it increases throughput by more than 60% compared to the best fixed-width configuration.
Learning to share
Authors: Rahul Hariharan , Kushman Nate , Katabi Dina , Sodini Charles , Edalat Farinaz
Published: August 2008

Wideband technologies in the unlicensed spectrum can satisfy the ever-increasing demands for wireless bandwidth created by emerging rich media applications. The key challenge for such systems, however, is to allow narrowband technologies that share these bands (say, 802.11 a/b/g/n, Zigbee) to achieve their normal performance, without compromising the throughput or range of the wideband network.

This paper presents SWIFT, the first system where high-throughput wideband nodes are shown in a working deployment to coexist with unknown narrowband devices, while forming a network of their own. Prior work avoids narrowband devices by operating below the noise level and limiting itself to a single contiguous unused band. While this achieves coexistence, it sacrifices the throughput and operating distance of the wideband device. In contrast, SWIFT creates high throughput wireless links by weaving together non-contiguous unused frequency bands that change as narrowband devices enter or leave the environment. This design principle of cognitive aggregation allows SWIFT to achieve coexistence, while operating at normal power, and thereby obtaining higher throughput and greater operating range. We implement SWIFT on a wideband hardware platform, and evaluate it in the presence of 802.11 devices. In comparison to a baseline that coexists with narrowband devices by operating below their noise level, SWIFT is equally narrowband-friendly but achieves 3.6-10.5x higher throughput and 6x greater range.
To filter or to authorize
Authors: Liu Xin , Yang Xiaowei , Lu Yanbin
Published: August 2008

This paper presents the design and implementation of a filter-based DoS defense system (StopIt) and a comparison study on the effectiveness of filters and capabilities. Central to the StopIt design is a novel closed-control, open-service architecture: any receiver can use StopIt to block the undesired traffic it receives, yet the design is robust to various strategic attacks from millions of bots, including filter exhaustion attacks and bandwidth flooding attacks that aim to disrupt the timely installation of filters. Our evaluation shows that StopIt can block the attack traffic from a few millions of attackers within tens of minutes with bounded router memory. We compare StopIt with existing filter-based and capability-based DoS defense systems under simulated DoS attacks of various types and scales. Our results show that StopIt outperforms existing filter-based systems, and can prevent legitimate communications from being disrupted by various DoS flooding attacks. It also outperforms capability-based systems in most attack scenarios, but a capability-based system is more effective in a type of attack that the attack traffic does not reach a victim, but congests a link shared by the victim. These results suggest that both filters and capabilities are highly effective DoS defense mechanisms, but neither is more effective than the other in all types of DoS attacks.