bluuebunny/crossref_metadata_2025 huggingface dataset:
Pigmentation pattern evolution in delphinid cetaceans: an essay in adaptive coloration
Authors: Mitchell Edward
Published: August 2008

Dolphins and porpoises have complex pigmentation patterns. A terminology is devised for the complicated pattern on Delphinus delphis, and is applied to related species. A Stenella–Delphinus species group is recognized, with species which can be segregated into four pigmentation pattern types: STRIPED, CRISSCROSS, SADDLED, and SPOTTED. Morphological derivations indicate that saddled is like simple countershading; could independently have given rise to striped, spotted, or crisscross patterns; and is thus inferred to be the most generalized pattern of the four. Crisscross pattern is the most complex, possibly the most specialized, and occurs only on Delphinus. Other morphological evidence from rostral grooves and cranial air sinuses likewise indicates that Delphinus is more specialized than Stenella. The saddled pattern on Stenella is thus generalized and probably also primitive within the Delphinidae.An overlook of other delphinid species confirms that the saddled pattern is generalized and probably primitive. The Lissodelphinae show a generalized pattern; that of the Orcininae can be related to it. Species of the genus Lagenorhynchus show a gradation in the extent and increasing complexity of the dorsal flank blaze from L. obscurus and L. australis through L. obliquidens, L. albirostris, and L. cruciger to L. acutus. The two allopatric species L. cruciger and L. acutus are both specialized in the subdivision of the flank patch. Selection for blazes dorsoanteriorly on the trunk resulted in extension of flank blazes in Lagenorhynchus, of thoracic blazes in Stenella. L. acutus and D. delphis, among the most specialized representatives of genera Lagenorhynchus and Delphinus, respectively, independently evolved a yellow-brown side patch—it is on the flank of the former, on the thorax of the latter. The Cephalorhynchinae show patterns related to saddled, and perhaps paralleled the Orcininae in pigmentation trends. Cephalorhynchus heavisidei appears to be a mimic of Orcinus orca. C. commersoni and the allopatric phocoenid Phocoenoides truei appear to be convergent—both are disruptively pigmented in the same way. Additional pigmentation types recognized are UNIFORM, LOBED, and DISRUPTIVE.In the Stenella–Delphinus species group: the saddled pattern is possibly for obliterative shading through counterlighting for concealment; the striped pattern is possibly for disguise through disruptive pigmentation and camouflage; the spotted pattern on a countershaded base is possibly for camouflage by resemblance to background; and the crisscross pattern is possibly for disguise through disruptive pigmentation, and camouflage by countershading and shadow mimicry. On most delphinids, eye patches, bridle stripes, and lip patches serve to mask eyes, blowhole, and mouth. The thoracic patch may be a false shadow to conceal young swimming in echelon formation.Striped or Euphrosyne dolphins of Pacific and Atlantic waters are conspecific. Distinct subspecies of Stenella caeruleoalba are disallowed as yet unproved.
Differences between the livers of spawning male and female sea lamprey (Petromyzon marinus)
Authors: Kott E.
Published: August 2008

Migratory sea lampreys (Petromyzon marinus) were collected in spring from rivers flowing into Lakes Ontario, Erie, and Huron. Lengths, weights, liver weights, and liver colors were recorded. Livers were analyzed for fat, water, and protein content. Transmission spectra of chloroform extracts of liver pigments were also obtained. Female livers from Lake Ontario and Lake Huron lamprey were larger than male livers, whereas male livers of Lake Erie lamprey were larger than female livers. In all three samples female livers developed a green coloration more rapidly than did male livers, as a result of a more rapid accumulation of biliverdin. Male livers had a much higher fat content, but by the end of spawning even these livers had a reduced fat content. Initially the water content of male livers was much lower but by spawning time no real difference was found between male and female livers. No significant difference could be detected in the protein content of male and female livers.
Comparison of hearts and branchial heart appendages in some cephalopods
Authors: Martin Arthur W. , Aldrich Frederick A.
Published: August 2008

Seawater was used to perfuse the branchial heart appendages of Octopus dofleini and Illex illecebrosus. At comparable pressures the filtration rates expressed in ml/mg per hour showed a remarkable correspondence. The weights of the branchial heart appendages, the branchial hearts, and the systemic hearts, relative to total body weight, were therefore determined for several cephalopods of widely different body size.
A late summer checklist of the marine microbiota around Logy Bay, Newfoundland
Authors: Lackey James B. , Lackey Elsie W.
Published: August 2008

In late July and early August 1969 intensive study of a variety of habitats around the Marine Sciences Research Laboratory, Memorial University of Newfoundland, yielded a total of 202 taxa of sulfur bacteria, microscopic algae, and protozoa. This list is relatively small, as was the number of sampling stations. The numbers per milliliter or per liter were very few, and the area is regarded as one of low productivity.Most of the organisms are cosmopolitan, having been found in widely different situations elsewhere. A very few have been found by us only at Logy Bay. The ciliates Parafavella gigantea and Helicostomella sp. occurred in some abundance and may be cold water species. A new ciliate of the genus Myelostoma was quite abundant and will be described elsewhere.
Variation in song patterns of Antipodean Teleogryllus species (Orthoptera: Gryllidae) and a proposed phenetic classification
Authors: Madsen C. , Vickery V. R. , Nowosielski J.
Published: August 2008

The stridulations of eight sample populations of Teleogryllus commodus servillei (Saussure) and T. oceanicus (Le Guillou) were recorded and analyzed. Sokal's "distance coefficient" formula was used to derive a phenetic classification of the populations. The analysis indicates the same relationships as were previously indicated, by Chen et al. (1967) on morphological evidence, and by Lim et al. (1969) on cytological study.
Trypanosoma avium Danilewsky in the avian host
Authors: Bennett Gordon F.
Published: August 2008

The course of parasitaemia of three strains of Trypanosoma avium Danilewsky, 1885 were followed in the avian host. Indications of a cyclical increase in circulating parasites was obtained. Evidence also indicated that the level of parasitaemia was correlated with the number of flagellates initially inoculated and that previous infection with T. avium conferred a degree of immunity on the avian host.
Sex ratios and survival in fluctuating populations of the deer mouse, Peromyscus mamculatus borealis
Authors: Canham Raymond P.
Published: August 2008

In litters of the deer mouse, Peromyscus mamculatus borealis, born in captivity there was a significantly greater number of males than females. In natural populations of the same subspecies, an excess of males caused the sex ratio in captured young of the year to differ significantly from 1:1 only in those summers in which population density increased considerably. The sex ratio did not change appreciably during a winter in which density remained stable, but in winters of low survival the proportion of males declined. A difference between males and females in the amplitude of the fluctuations in postnatal survival thus appeared responsible for variations in the sex ratio.
The deciduous dentition and its replacement in Myotis lucifugus (Chiroptera: Vespertilionidae)
Authors: Fenton M. Brock
Published: August 2008

The deciduous teeth of Myotis lucifugus and the sequence of their replacement by the permanent teeth are described. Juveniles possessing erupted adult dentitions were capable of flight and, for the first time, had insect remains in their digestive tracts.
The neuroendocrine organs in adult Noctuidae
Authors: Hinks C. F.
Published: August 2008

A detailed study of the innervation of the neuroendocrine organs in eight species of Noctuidae has revealed a previously undescribed network of serves. A dorsal branch of the outer pair of nerves connecting the protocerebrum with the corpora cardiaca bears fine nerves extending to the ocellar, antennal, and optic nerves and to the orbital setae. A distinct ventrally directed nerve arising from each corpus cardiacum has branches extending to the optic, maxillary, and palpal nerve and lateral orbital setae. The possible significance of these nerves is discussed in the context of known endocrine functions.
Effects of cold-acclimation on supercooling and survival of the rusty grain beetle, Cryptolestes ferrugineus (Stephens) (Coleoptera: Cucujidae), at subzero temperatures
Authors: Smith L. B.
Published: August 2008

The survival of non-acclimated adults and large larvae (third and fourth instar) of Cryptolestes ferrugineus (Stephens) was found to be greater than that of pupae, small larvae (first instar), and eggs at −12°, −6°, and 2 °C. The effect of acclimation on adult survival at subfreezing temperatures was determined. Different degrees of acclimation were achieved by exposing adults for different periods of time at 15 °C. At −6° and −12 °C adult survival increased as the time of acclimation increased. The LT50 of acclimated adults increased as much as nine times at − 6 °C and 56 times at −12 °C compared to the LT50 of non-acclimated adults. The supercooling point of adults was lowered from −16.5 °C for non-acclimated adults to − 20 °C for adults acclimated at 15 °C and to −21 °C for adults acclimated at 15° and then 4 °C. It is suggested that C. ferrugineus is able to survive the winter in unheated granaries in the Prairie Provinces mainly because of its ability to acclimate to low temperatures.
Response of host embryonic chicks to grafts of additional adrenal glands. 1. Response of host adrenal glands, gonads, and kidneys
Authors: Hall B. K.
Published: August 2008

The response of host embryonic chicks to the presence of additional amounts of adrenal gland tissue has been explored by grafting an additional gland from an 18-day embryonic donor to the chorioallantoic membrane of an 8-day embryonic host. The grafts were maintained for up to 10 days.The graft had no effect on the body weight of the host, nor on proliferation within the kidney. Proliferation within the gonad of the host was significantly depressed from 1 day postgrafting.Effects of the graft on the host adrenal glands were confined to hyperplasia of cortical tissue up to 12 days of incubation and subsequent reduced proliferation to 18 days. The medullary tissue did not respond to the graft.The significance of these results is discussed in terms of normal development of the adrenal gland, seasonal variations in adrenal function, and the establishment of the adrenal–gonad axis.
Large schizonts of Leucocytozoon from the kidney of the ruffed grouse (Bonasa umbellus)
Authors: Newman Martin W.
Published: August 2008

Large schizonts of Leucocytozoon sp. were found in kidney tissue of two drumming ruffed grouse shot in the aspen parkland of central Alberta.The schizonts were in advanced stages of development. Some appeared to have ruptured, releasing merozoites. These schizonts were similar in several respects to the megaloschizonts of L. simondi. Examination of sections of spleen, liver, lung, and brain failed to reveal large schizonts. Blood smears from one of the grouse contained numerous young gametocytes.
The influence of behavioral differences among tent-caterpillar larvae on predation by a pentatomid bug
Authors: Iwao S. , Wellington W. G.
Published: August 2008

Active larvae of the western tent caterpillar, Malacosoma californicum pluviale (Dyar), were stalked more consistently by the predator, Podisus maculiventris Say, than their sluggish counterparts. In the fourth instar, the active individuals were too small to defend themselves, so they were eaten more frequently than sluggish larvae. In the fifth instar, active larvae defended themselves more successfully, whereas sluggish larvae did not. Among these older larvae, therefore, fewer active and more sluggish individuals were successfully attacked.
Probabilistic phototactic behavior in a bark beetle
Authors: Kimmins J. P.
Published: August 2008

An anomaly was observed during an investigation of the spectral response behavior of a bark beetle. Repeatable group responses were obtained in a multiple-choice test, but the response of individual beetles in the groups varied. Data are presented to illustrate this phenomenon. No explanation is presented, but it is suggested that individual photic responses to a multiple choice of wavelengths may conform to some probability distribution characteristic of the species, resulting in a constant group response which reflects this probability distribution.
The quantitative distribution of three Cumacea (Crustacea, Peracarida) in Kames Bay, Scotland
Authors: Corey S.
Published: August 2008

Comparative studies of the quantitative distribution and factors influencing the distribution are described for three species of cumaceans in Kames Bay, Scotland.Cumopsis goodsiri is restricted to the intertidal zone. The outer limits of distribution are controlled by a combination of sand grain size, exposure period and drainage. Iphinöe trispinosa is restricted to the sandy sublittoral zone from low-water mark to where the bottom begins to grade into mud. Pseudocuma longicornis overlaps completely with I. trispinosa and also extends into the sublittoral zone to mean low-water spring mark.The highest density for each species in Kames Bay is C. goodsiri, 30 per [Formula: see text]; I. trispinosa, 64 per [Formula: see text]; P. longicornis, 272 per [Formula: see text].
A rickettsialike microorganism in Dahlbominus fuscipennis (Zett.) (Hymenoptera, Eulophidae): observations on its occurrence and ultrastructure
Authors: Byers J. R. , Wilkes A.
Published: August 2008

An intracellular microorganism found in D. fuscipennis exhibits the basic morphology characteristic of rickettsiae. It is regularly present in the gonads and abdominal ganglia, less frequently in other tissues. The rickettsia has no overt cytopathic effect in host cells, does not noticeably affect the fitness of the host, and is likely transmitted transovarially. On the basis of arthropod association, morphology, and relationship to the host cell the rickettsia resembles members of the genus Wolbachia. Its relationship with the host and the significance of a host-provided membrane enclosing each rickettsia are discussed.
Reproduction and breeding cycle of the giant scallop Placopecten magellanicus (Gmelin) in Port au Port Bay, Newfoundland
Authors: Naidu K. S.
Published: August 2008

Gametogenesis and spawning are described for a population of the giant scallop, Placopecten magellanicus (Gmelin), in Port au Port Bay, Newfoundland. Histological changes accompanying the breeding cycle are discussed.A few individuals spawn in early summer (June) and also participate in the major spawning which takes place in autumn (September–October).
Quelques Eugrégarines parasites d'Invertébrés marins de St. Andrews (Nouveau-Brunswick)
Authors: Théodoridès Jean , Laird Marshall
Published: August 2008

The occurrence of six species of coelomic or intestinal eugregarines from marine invertebrates of St. Andrews, New Brunswick, is recorded herein.One of them (Pterospora clymenellae n.sp.) is new to science, and the others (with the exception of Urospora chiridotae) appear to constitute new additions to the Canadian fauna.
Response of newt larvae to X-irradiation
Authors: Friedmann G. B. , McCurdy H. M. , Algard F. T.
Published: August 2008

Graded doses of from 200 to 2000 rad of x-rays were administered to premetamorphic Taricha torosa larvae of various ages. General stunting, specific malformation, pigmentary damage, and a very shortened life-span occurred at all doses. There is an age-dependent dose response; some animals exposed to 200 and 600 rad survived to complete metamorphosis. Evidence is presented supporting a view that postmetamorphic epidermal melanocytes may be derived largely by division of an unpigmented progenitor cell type.
Brucellosis in reindeer, Rangifer tarandus L., and the migratory barren-ground caribou, Rangifer tarandus groenlandicus (L.), in Canada
Authors: Broughton E. , Choquette L. P. E. , Cousineau J. G. , Miller F. L.
Published: August 2008

Serum samples from 1692 reindeer slaughtered in the Mackenzie River Delta in the last decade and from 320 Kaminuriak barren-ground caribou killed between June 1966 and July 1968 were tested for brucellosis. All sera yielding titers of 1:25 or higher were considered to be positive. A positive reaction was obtained in 148 of the 1692 reindeer and 14 of the 320 barren-ground caribou tested, giving an overall reactor percentage of 8.74 in reindeer and 4.37 in caribou.Orchitis, epididymitis, bursitis, metritis, abortion, and placental retention—conditions associated with brucellosis in reindeer in the U.S.S.R. and caribou in Alaska—were not noted in the autopsy of the 1692 reindeer and of 500 sexually mature barren-ground caribou. Three possible records of bursitis, of unknown nature, in barren-ground caribou are discussed. Seemingly, brucellosis does not represent a serious threat to either the Mackenzie River Delta reindeer or the Kaminuriak barren-ground caribou population, but its detection in these animal populations is of interest from a public health standpoint.
The harp seal, Pagophilus groenlandicus (Erxleben, 1777). I. Methods of handling, molt, and diseases in captivity
Authors: Ronald K. , Johnson E. , Foster M. , Pol D. Vander
Published: August 2008

Methods of capturing harp seals and maintaining them in captivity are described, and the molt and symptoms of various diseased animals are discussed together with postmortem findings.
Sexual dimorphism in the chela of Orconectes virilis (Hagen)
Authors: Weagle K. V. , Ozburn G. W.
Published: August 2008

The length and width of the left and right chela and the carapace length of 67 mature crayfish were measured to [Formula: see text]. The regression lines for the carapace length vs. chela length showed a measurable difference in chela length for the three adult groups. Form I male chela were found to be 19% longer and 12% wider than the form II male chela and 24% longer and 16% wider than the female chela. The form II male chela were 8% longer and 5% wider than the female chela. The ratio of chela length to chela width showed that the chela of all the three groups had slightly different shapes.
Observations on the morphology and life cycle of Hymenolepis hopkinsi Schiller 1951 (Cestoda: Cyclophyllidea), a parasite of black ducks (Anas rubripes Brewster)
Authors: McLaughlin J. Daniel , Burt Michael D. B.
Published: August 2008

Twenty-six of 65 black ducks (Anas rubripes) collected in New Brunswick from August 15, 1967, to December 15, 1969, have been found to harbor the cestode Hymenolepis hopkinsi Schiller, 1951. This cestode occurs in the caeca with the number of worms per bird ranging from 2 to 774 during the present study. Infections of 100–200 worms are common. The life cycle has been elucidated and egg strings, fed to Hyalella azteca, developed into viable cysticercoids. The resulting cysticercoids, when fed to a domestic duck, developed into adult cestodes. The life cycle is described along with a brief description of the adult. The characteristic egg strings and the cysticercoid are also described.
Variations in fecundity of the red squirrel, Tamiasciurus hudsonicus (Erxleben)
Authors: Millar John S.
Published: August 2008

Ovulation rates, preimplantation losses, and postimplantation losses of red squirrels in southern British Columbia were examined in relation to age, area, and year, and related to population density and food supply. Ovulation rates were extremely variable, and appeared to be influenced by the food supply. Preimplantation losses were higher in yearlings (22.7%) than in adults (7.4%), and totalled 11.3% of all ova shed. Postimplantation losses totalled 7.7% of all implanted embryos.
Resistance of mice to Toxocara canis: effect of prechallenge infections and injections of worm extracts
Authors: Izzat N. N. , Olson L. J.
Published: August 2008

Test mice have been infected one or more times and challenged with Toxocara canis larvae in an attempt to demonstrate acquired resistance to this nematode in a paratenic host. The worm burden of these mice at necropsy was not significantly less than that for controls.Mice given prechallenge injections of somatic fractions of T. canis eggs and adult worms, together with adjuvant, were found to harbor significantly fewer larvae after a challenge infection than did controls. The worm burden of mice similarly injected with fractions of adult Ascaris lumbricoides had worm burdens after challenge which were about equal to that of controls.
Activity response to oxygen in the brook trout, Salvelinus fontinalis (Mitchill)
Authors: Dandy J. W. T.
Published: August 2008

Locomotory activity of brook trout was measured at 10 °C in water of three different oxygen concentrations. Activity was sensed with a thermistor probe in a Wheatstone bridge circuit. Voltage output of the bridge was integrated automatically and recorded.Exposure to 6.0 and 1.7 p.p.m. oxygen induced tin activity response within minutes which reached a peak during the first hour then slowly waned. The intensity of response was greater to lower than to higher oxygen levels. Not all fish responded to 8.0 p.p.m. The response threshold concentration was estimated to be 8.3 p.p.m. oxygen. The response appeared to be made to the absolute concentration rather than to the rate of oxygen decrease.Various difficulties in estimating thresholds for dissolved substances in a constant flow system are considered. It is suggested that the response threshold found here be applied only in the specific circumstances of this experiment.
The innervation of the thorax of the adult milkweed bug Oncopeltus fasciatus (Dallas). 1. The prothorax
Authors: Govind C. K. , Dandy J. W. T.
Published: August 2008

An account is given of the prothoracic innervation of the milkweed bug Oncopeltus fasciatus (Dallas) by tracing the ramifications and terminations of each of the seven paired nerves. The principal leg nerve, 6, is traced to the coxa only.
Freshwater ostracodes of Canada. Part III. Family Candonidae
Authors: Delorme L. D.
Published: August 2008

The family Candonidae is represented in Canada by 33 species belonging to three genera Candona, Paracandona, and Candocyprinotus. The genus Candona is represented by 31 species of which two, Candona facetus and Candona subacuminata, are new. A new genus, intermediate between Candona and Cyprinotus, has been found in Canada, namely Candocyprinotus ovatus.
The occurrence of Echinococcus multilocularis Leuckart, 1863 and of other helminths in the red fox, Vulpes vulpes, in southern Manitoba
Authors: Baron R. W.
Published: August 2008

Echinococcus multilocularis was found in 1 of 75 foxes collected from the Morris area, 30 mi south of Winnipeg. Toxocara canis was present in 71, Taenia crassiceps in 7, and Alaria alata in 3 of the foxes examined.
Dispersion in a natural population of three-spined sticklebacks
Authors: Black Robert , Wootton R. J.
Published: August 2008

Territorial male three-spined sticklebacks, Gasterosteus aculeatus form trachurus, in a splash pool were dispersed uniformly. Their nests tended to occur in sheltered locations, but the presence of exposed nests and the uniform dispersion suggested that all the suitable space for territories was used. If original males, removed from their territories, did not return, new males became territorial.
Ixodes spinipalpis Hadwen and Nuttall (Ixodidae) from southern Alberta
Authors: Shemanchuk J. A. , Kiceniuk J. W.
Published: August 2008

Five nymphs and one larva of Ixodes spinipalpis Hadwen and Nuttall were collected from a grey bushy-tailed wood rat, Neotoma cinerea cinerea (Ord.) in a prairie habitat in southern Alberta.
IMPACTS OF AGEING POPULATION ON MONETARY AND EXCHANGE RATE MANAGEMENT IN SINGAPORE
Authors: YIP PAUL S. L. , TAN K. C.
Published: August 2008

This policy note finds that the ageing of the population in Singapore will cause a reversal of the current net Central Provident Fund (CPF) contribution into a substantial net CPF withdrawal from 2025, with a peak occurring at 2035. The result is qualitatively robust to changes in the underlying assumptions of the projection. The paper then highlights the implications of this change on the exchange rate and monetary management in Singapore. Finally, the paper proposes policy measures that can help (a) mop up the excess liquidity due to the net CPF withdrawals; and (b) maintain the Monetary Authority of Singapore (MAS)'s influence on Singapore's exchange rate at a reasonable level in the longer future.
LONG-RUN RELATIONSHIP BETWEEN IMPORTS AND EXPORTS: EVIDENCE FROM ASIAN COUNTRIES
Authors: AFZAL MOHAMMAD
Published: August 2008

We used Engle–Granger cointegration test to investigate and compare the long-run performance of imports and exports in Pakistan, India, Sri Lanka, Korea and Thailand. Graphical analysis demonstrates an inherent tendency of imports and exports to move together in the long run. Cointegration and error correction results support the graphical analysis that these countries do not violate on the average the international budget constraint, and trade disequilibrium is a short-run phenomenon that is sustainable in the long run. Macroeconomic policies in the sample countries have been adequately effective to affect long-run equilibrium between imports and exports. The international events had differential impact on each country of our sample.
CASSON KNOT INVARIANTS OF PERIODIC KNOTS WITH RATIONAL QUOTIENTS II
Authors: LEE SANG YOUL , SEO MYOUNGSOO
Published: August 2008

For any integers n1, n2, …, nm, we give a formula for the Casson knot invariant of a p-periodic knot (p ≥ 2) whose quotient link is a 2-bridge link with Conway's normal form C(2, 2n1 + 1, -2, 2n2 + 1, …, 2nm + 1, (-1)m2).
THE COLORED JONES POLYNOMIALS OF DOUBLES OF KNOTS
Authors: TANAKA TOSHIFUMI
Published: August 2008

We give formulas for the N-colored Jones polynomials of doubles of knots by using skein theory. As a corollary, we show that if the volume conjecture for untwisted positive (or negative) doubles of knots is true, then the colored Jones polynomial detects the unknot.
CHARACTERIZATION FOR THE MODULAR PARTY ALGEBRA
Authors: KOSUDA M.
Published: August 2008

In this paper, we give a characterization for the modular party algebra Pn,r(Q) by generators and relations. By specializing the parameter Q to a positive integer k, this algebra becomes the centralizer of the unitary reflection group G(r, 1, k) in the endomorphism ring of V⊗n under the condition that k ≥ n.
THE QUANTUM CONTENT OF THE NORMAL SURFACES IN A THREE-MANIFOLD
Authors: FROHMAN CHARLES , KANIA-BARTOSZYNSKA JOANNA
Published: August 2008

The formula for the Turaev–Viro invariant of a three-manifold depends on a complex parameter t. When t is not a root of unity, the formula becomes an infinite sum. This paper analyzes convergence of this sum when t does not lie on the unit circle, in the presence of an efficient triangulation of the three-manifold. The terms of the sum can be indexed by surfaces lying in the three-manifold. The contribution of a surface is largest when the surface is normal and when its genus is the lowest.
STABILIZING HEEGAARD SPLITTINGS OF COMPOSITE TUNNEL NUMBER TWO KNOTS
Authors: LEE JUNG HOON
Published: August 2008

Suppose K # K′ is a composite tunnel number two knot where both K and K′ are tunnel number one knots. Let t1, t2 be unknotting tunnels of K and t′1 , t′2 be unknotting tunnels of K′ and assume that cl (S3 - N(K ∪ t1 ∪ t2)) and cl (S3 - N(K′ ∪t′1 ∪t′2)) are genus three handlebodies.

Suppose {t1 , t′1} , {t2 , t′2} are tunnel systems of K # K′. Then we give some condition such that the two genus three Heegaard splittings induced by these tunnel systems become isotopic by one stabilization.

On the other hand, we construct infinitely many examples such that cl (S3 - N(K # K′ ∪ t1 ∪ t′1 ∪ t′2)) is not a genus four handlebody and give candidates of two splittings which cannot be made isotopic by a single stabilization.
FAMILIES OF HOLOMORPHIC BUNDLES
Authors: TELEMAN ANDREI
Published: August 2008

The first goal of the article is to solve several fundamental problems in the theory of holomorphic bundles over non-algebraic manifolds. For instance, we prove that stability and semi-stability are Zariski open properties in families when the Gauduchon degree map is a topological invariant, or when the parameter manifold is compact. Second, we show that, for a generically stable family of bundles over a Kähler manifold, the Petersson–Weil form extends as a closed positive current on the whole parameter space of the family. This extension theorem uses classical tools from Yang–Mills theory (e.g., the Donaldson functional on the space of Hermitian metrics and its properties). We apply these results to study families of bundles over a Kählerian manifold Y parametrized by a non-Kählerian surface X, proving that such families must satisfy very restrictive conditions. These results play an important role in our program to prove existence of curves on class VII surfaces [22–24].
IRREDUCIBLE SYMPLECTIC 4-FOLDS NUMERICALLY EQUIVALENT TO (K3)[2]
Authors: O'GRADY KIERAN G.
Published: August 2008

First steps toward a classification of irreducible symplectic 4-folds whose integral 2-cohomology with 4-tuple cup product is isomorphic to that of (K3)[2]. We prove that any such 4-fold deforms to an irreducible symplectic 4-fold of Type A or Type B. A 4-fold of Type A is a double cover of a (singular) sextic hypersurface and a 4-fold of Type B is birational to a hypersurface of degree at most 12. We conjecture that Type B 4-folds do not exist.
ASYMPTOTICS AND SYMMETRIES OF LEAST ENERGY NODAL SOLUTIONS OF LANE–EMDEN PROBLEMS WITH SLOW GROWTH
Authors: BONHEURE DENIS , BOUCHEZ VINCENT , GRUMIAU CHRISTOPHER , VAN SCHAFTINGEN JEAN
Published: August 2008

In this paper, we consider the Lane–Emden problem [Formula: see text] where Ω is a bounded domain in ℝN and p > 2. First, we prove that, for p close to 2, the solution is unique once we fix the projection on the second eigenspace. From this uniqueness property, we deduce partial symmetries of least energy nodal solutions. We also analyze the asymptotic behavior of least energy nodal solutions as p goes to 2. Namely, any accumulation point of sequences of (renormalized) least energy nodal solutions is a second eigenfunction that minimizes a reduced functional on a reduced Nehari manifold. From this asymptotic behavior, we also deduce an example of symmetry breaking. We use numerics to illustrate our results.
The ICFP developer conference 2008
Authors: Hook James , Sperber Michael
Published: August 2008

Functional Programming has seen greatly increased interest in recent years: From being an academic pursuit, functional programming is rapidly becoming a sought-after technology with increasingly broad applications. To accommodate the growing interest in FP, this year's International Conference on Functional Programming (in Victoria, British Columbia, Canada) will be followed by the ICFP Developer Conference, designed to help both decision-makers and developers to learn about the potential of functional programming for their projects, as well as gaining hands-on instruction on how to realize that potential.
Introduction
Authors: Falsafi Babak , Felber Pascal
Published: August 2008

In recent years, multiprocessors have emerged as the architecture of choice at the chip level to help ride Moore's law and continue exploiting the exponential growth in transistors while maintaining acceptable power consumption levels and complexity. Unfortunately, parallel software has not made it to the mainstream, making technologies to help facilitate parallel software development and programming for commodity chips critical to the sustained growth in IT infrastructure and industry. Transactional programming is emerging as a promising approach to help mitigate many of the difficulties associated with conventional synchronization and coordination mechanisms in parallel programs.
Xl
Authors: Levchenko Kirill , Voelker Geoffrey M. , Paturi Ramamohan , Savage Stefan
Published: August 2008

In this paper, we present a new link-state routing algorithm called Approximate Link state (XL) aimed at increasing routing efficiency by suppressing updates from parts of the network. We prove that three simple criteria for update propagation are sufficient to guarantee soundness, completeness and bounded optimality for any such algorithm. We show, via simulation, that XL significantly outperforms standard link-state and distance vector algorithms - in some cases reducing overhead by more than an order of magnitude - while having negligible impact on path length. Finally, we argue that existing link-state protocols, such as OSPF, can incorporate XL routing in a backwards compatible and incrementally deployable fashion.
What's going on?
Authors: Kandula Srikanth , Chandra Ranveer , Katabi Dina
Published: August 2008

Existing traffic analysis tools focus on traffic volume. They identify the heavy-hitters - flows that exchange high volumes of data, yet fail to identify the structure implicit in network traffic - do certain flows happen before, after or along with each other repeatedly over time? Since most traffic is generated by applications (web browsing, email, p2p), network traffic tends to be governed by a set of underlying rules. Malicious traffic such as network-wide scans for vulnerable hosts (mySQLbot) also presents distinct patterns.

We present eXpose, a technique to learn the underlying rules that govern communication over a network. From packet timing information, eXpose learns rules for network communication that may be spread across multiple hosts, protocols or applications. Our key contribution is a novel statistical rule mining technique to extract significant communication patterns in a packet trace without explicitly being told what to look for. Going beyond rules involving flow pairs, eXpose introduces templates to systematically abstract away parts of flows thereby capturing rules that are otherwise unidentifiable. Deployments within our lab and within a large enterprise show that eXpose discovers rules that help with network monitoring, diagnosis, and intrusion detection with few false positives.
Shadow configuration as a network management primitive
Authors: Alimi Richard , Wang Ye , Yang Y. Richard
Published: August 2008

Configurations for today's IP networks are becoming increasingly complex. As a result, configuration management is becoming a major cost factor for network providers and configuration errors are becoming a major cause of network disruptions. In this paper, we present and evaluate the novel idea of shadow configurations. Shadow configurations allow configuration evaluation before deployment and thus can reduce potential network disruptions. We demonstrate using real implementation that shadow configurations can be implemented with low overhead.
Network exception handlers
Authors: Karagiannis Thomas , Mortier Richard , Rowstron Antony
Published: August 2008

Enterprise network architecture and management have followed the Internet's design principles despite different requirements and characteristics: enterprise hosts are administered by a single authority, which intrinsically assigns different values to traffic from different business applications.

We advocate a new approach where hosts are no longer relegated to the network's periphery, but actively participate in network-related decisions. To enable host participation, network information, such as dynamic network topology and per-link characteristics and costs, is exposed to the hosts, and network administrators specify conditions on the propagated network information that trigger actions to be performed while a condition holds. The combination of a condition and its actions embodies the concept of the network exception handler, defined analogous to a program exception handler. Conceptually, network exception handlers execute on hosts with actions parameterized by network and host state.

Network exception handlers allow hosts to participate in network management, traffic engineering and other operational decisions by explicitly controlling host traffic under predefined conditions. This flexibility improves overall performance by allowing efficient use of network resources. We outline several sample network exception handlers, present an architecture to support them, and evaluate them using data collected from our own enterprise network.
Zigzag decoding
Authors: Gollakota Shyamnath , Katabi Dina
Published: August 2008

This paper presents ZigZag, an 802.11 receiver design that combats hidden terminals. ZigZag's core contribution is a new form of interference cancellation that exploits asynchrony across successive collisions. Specifically, 802.11 retransmissions, in the case of hidden terminals, cause successive collisions. These collisions have different interference-free stretches at their start, which ZigZag exploits to bootstrap its decoding.

ZigZag makes no changes to the 802.11 MAC and introduces no overhead when there are no collisions. But, when senders collide, ZigZag attains the same throughput as if the colliding packets were a priori scheduled in separate time slots. We build a prototype of ZigZag in GNU Radio. In a testbed of 14 USRP nodes, ZigZag reduces the average packet loss rate at hidden terminals from 72.6% to about 0.7%.
Spamming botnets
Authors: Xie Yinglian , Yu Fang , Achan Kannan , Panigrahy Rina , Hulten Geoff , Osipkov Ivan
Published: August 2008

In this paper, we focus on characterizing spamming botnets by leveraging both spam payload and spam server traffic properties. Towards this goal, we developed a spam signature generation framework called AutoRE to detect botnet-based spam emails and botnet membership. AutoRE does not require pre-classified training data or white lists. Moreover, it outputs high quality regular expression signatures that can detect botnet spam with a low false positive rate. Using a three-month sample of emails from Hotmail, AutoRE successfully identified 7,721 botnet-based spam campaigns together with 340,050 unique botnet host IP addresses.

Our in-depth analysis of the identified botnets revealed several interesting findings regarding the degree of email obfuscation, properties of botnet IP addresses, sending patterns, and their correlation with network scanning traffic. We believe these observations are useful information in the design of botnet detection schemes.
Enriching network security analysis with time travel
Authors: Maier Gregor , Sommer Robin , Dreger Holger , Feldmann Anja , Paxson Vern , Schneider Fabian
Published: August 2008

In many situations it can be enormously helpful to archive the raw contents of a network traffic stream to disk, to enable later inspection of activity that becomes interesting only in retrospect. We present a Time Machine (TM) for network traffic that provides such a capability. The TM leverages the heavy-tailed nature of network flows to capture nearly all of the likely-interesting traffic while storing only a small fraction of the total volume. An initial proof-of-principle prototype established the forensic value of such an approach, contributing to the investigation of numerous attacks at a site with thousands of users. Based on these experiences, a rearchitected implementation of the system provides flexible, highperformance traffic stream capture, indexing and retrieval, including an interface between the TM and a real-time network intrusion detection system (NIDS). The NIDS controls the TM by dynamically adjusting recording parameters, instructing it to permanently store suspicious activity for offline forensics, and fetching traffic from the past for retrospective analysis. We present a detailed performance evaluation of both stand-alone and joint setups, and report on experiences with running the system live in high-volume environments.
Packet caches on routers
Authors: Anand Ashok , Gupta Archit , Akella Aditya , Seshan Srinivasan , Shenker Scott
Published: August 2008

Many past systems have explored how to eliminate redundant transfers from network links and improve network efficiency. Several of these systems operate at the application layer, while the more recent systems operate on individual packets. A common aspect of these systems is that they apply to localized settings, e.g. at stub network access links. In this paper, we explore the benefits of deploying packet-level redundant content elimination as a universal primitive on all Internet routers. Such a universal deployment would immediately reduce link loads everywhere. However, we argue that far more significant network-wide benefits can be derived by redesigning network routing protocols to leverage the universal deployment. We develop "redundancy-aware" intra- and inter-domain routing algorithms and show that they enable better traffic engineering, reduce link usage costs, and enhance ISPs' responsiveness to traffic variations. In particular, employing redundancy elimination approaches across redundancy-aware routes can lower intra and inter-domain link loads by 10-50%. We also address key challenges that may hinder implementation of redundancy elimination on fast routers. Our current software router implementation can run at OC48 speeds.
Rd network services
Authors: Podlesny Maxim , Gorinsky Sergey
Published: August 2008

With the Internet offering a single best-effort service, there have been numerous proposals of diversified network services that align better with the divergent needs of different distributed applications. The failure of these innovative architectures to gain wide deployment is primarily due to economic and legacy issues, rather than technical shortcomings. We propose a new paradigm for network service differentiation where design principles account explicitly for the multiplicity of Internet service providers and users as well as their economic interests in environments with partly deployed new services. Our key idea is to base the service differentiation on performance itself, rather than price. The proposed RD (Rate-Delay) services enable a user to choose between a higher transmission rate or low queuing delay at a congested network link. An RD router supports the two services by maintaining two queues per output link and achieves the intended rate-delay differentiation through simple link scheduling and dynamic buffer sizing. After analytically deriving specific rules for RD router operation, we conduct extensive simulations that confirm effectiveness of the RD services geared for incremental deployment in the Internet.
Rationality and traffic attraction
Authors: Goldberg Sharon , Halevi Shai , Jaggard Aaron D. , Ramachandran Vijay , Wright Rebecca N.
Published: August 2008

We study situations in which autonomous systems (ASes) may have incentives to send BGP announcements differing from the AS-level paths that packets traverse in the data plane. Prior work on this issue assumed that ASes seek only to obtain the best possible outgoing path for their traffic. In reality, other factors can influence a rational AS's behavior. Here we consider a more natural model, in which an AS is also interested in attracting incoming traffic (e.g., because other ASes pay it to carry their traffic). We ask what combinations of BGP enhancements and restrictions on routing policies can ensure that ASes have no incentive to lie about their data-plane paths. We find that protocols like S-BGP alone are insufficient, but that S-BGP does suffice if coupled with additional (quite unrealistic) restrictions on routing policies. Our game-theoretic analysis illustrates the high cost of ensuring that the ASes honestly announce data-plane paths in their BGP path announcements.
Unconstrained endpoint profiling (googling the internet)
Authors: Trestian Ionut , Ranjan Supranamaya , Kuzmanovi Aleksandar , Nucci Antonio
Published: August 2008

Understanding Internet access trends at a global scale, i.e., what do people do on the Internet, is a challenging problem that is typically addressed by analyzing network traces. However, obtaining such traces presents its own set of challenges owing to either privacy concerns or to other operational difficulties. The key hypothesis of our work here is that most of the information needed to profile the Internet endpoints is already available around us - on the web.

In this paper, we introduce a novel approach for profiling and classifying endpoints. We implement and deploy a Google-based profiling tool, which accurately characterizes endpoint behavior by collecting and strategically combining information freely available on the web. Our 'unconstrained endpoint profiling' approach shows remarkable advances in the following scenarios: (i) Even when no packet traces are available, it can accurately predict application and protocol usage trends at arbitrary networks; (ii) When network traces are available, it dramatically outperforms state-of-the-art classification tools; (iii) When sampled flow-level traces are available, it retains high classification capabilities when other schemes literally fall apart. Using this approach, we perform unconstrained endpoint profiling at a global scale: for clients in four different world regions (Asia, South and North America and Europe). We provide the first-of-its-kind endpoint analysis which reveals fascinating similarities and differences among these regions.
Interactive wifi connectivity for moving vehicles
Authors: Balasubramanian Aruna , Mahajan Ratul , Venkataramani Arun , Levine Brian Neil , Zahorjan John
Published: August 2008

We ask if the ubiquity of WiFi can be leveraged to provide cheap connectivity from moving vehicles for common applications such as Web browsing and VoIP. Driven by this question, we conduct a study of connection quality available to vehicular WiFi clients based on measurements from testbeds in two different cities. We find that current WiFi handoff methods, in which clients communicate with one basestation at a time, lead to frequent disruptions in connectivity. We also find that clients can overcome many disruptions by communicating with multiple basestations simultaneously. These findings lead us to develop ViFi, a protocol that opportunistically exploits basestation diversity to minimize disruptions and support interactive applications for mobile clients. ViFi uses a decentralized and lightweight probabilistic algorithm for coordination between participating basestations. Our evaluation using a two-month long deployment and trace-driven simulations shows that its link-layer performance comes close to an ideal diversity-based protocol. Using two applications, VoIP and short TCP transfers, we show that the link layer performance improvement translates to better application performance. In our deployment, ViFi doubles the number of successful short TCP transfers and doubles the length of disruption-free VoIP sessions compared to an existing WiFi-style handoff protocol.
The Genetics and Cell Biology of Wolbachia-Host Interactions
Authors: Serbus Laura R. , Casper-Lindley Catharina , Landmann Frédéric , Sullivan William
Published: August 2008

Wolbachia are gram-negative bacteria that are widespread in nature, carried by the majority of insect species as well as some mites, crustaceans, and filarial nematodes. Wolbachia can range from parasitic to symbiotic, depending upon the interaction with the host species. The success of Wolbachia is attributed to efficient maternal transmission and manipulations of host reproduction that favor infected females, such as sperm-egg cytoplasmic incompatibility (CI). Much remains unknown about the mechanistic basis for Wolbachia-host interactions. Here we summarize the current understanding of Wolbachia interaction with insect hosts, with a focus on Drosophila. The areas of discussion include Wolbachia transmission in oogenesis, Wolbachia distribution in spermatogenesis, induction and rescue of the CI phenotype, Wolbachia genomics, and Wolbachia-membrane interactions.