Relationship between intramammary infection prevalence and somatic cell score in commercial dairy herds.

We examined consistency of the relationship between intramammary infection (IMI) and somatic cell score (SCS) across several classes of cow, herd, and sampling time variables. Microbial cultures of composite milk samples were performed by New York Quality Milk Production Services from 1992 to 2004. SCS was from the most recent Dairy Herd Improvement test before IMI sampling. Records were analyzed from 79,308 cows in 1,124 commercial dairy herds representing a broad range of production systems. Three binary dependent variables were presence or absence of contagious IMI, environmental IMI, and all IMI. Independent variables in the initial models were SCS, SCS2, lactation number, days in milk, sample day milk yield, use of coliform mastitis vaccine, participant type (required by regulation or voluntary), production system (type of housing, milking system, and herd size), season of sampling, year of sampling, and herd; also the initial models included interactions of SCS and SCS2 with other independent variables, except herd and milk yield. Interaction terms characterize differences in the IMI-SCS relationship across classes of the independent variables. Models were derived using the Glimmix macro in SAS (SAS Institute Inc., Cary, NC) with a logistic link function and employing backward elimination. The final model for each dependent variable included all significant independent variables and interactions. Simplified models omitted SCS2 and all interactions with SCS. Interactions of SCS with days in milk, use of coliform mastitis vaccine, participant type, season, and year were not significant in any of the models. Interaction of SCS with production system was significant for the all IMI model, whereas interaction of SCS with lactation number was significant for the environmental and all IMI models. Each 1-point increase in SCS (or doubling of somatic cell count) was associated with a 2.3, 5.5, and 9.1% increase in prevalence of contagious, environmental, and all IMI, respectively. Empirical receiver operator characteristic curves and areas under the curve were derived for final and simplified models. The areas under the curve for simplified and final models within each type of IMI differed by 0.009 or less. We concluded that the relationship of IMI with SCS was generally stable over time and consistent across seasons, production systems, and cow factors.

Spectral properties of Titan's impact craters imply chemical weathering of its surface.

We examined the spectral properties of a selection of Titan's impact craters that represent a range of degradation states. The most degraded craters have rims and ejecta blankets with spectral characteristics that suggest that they are more enriched in water ice than the rims and ejecta blankets of the freshest craters on Titan. The progression is consistent with the chemical weathering of Titan's surface. We propose an evolutionary sequence such that Titan's craters expose an intimate mixture of water ice and organic materials, and chemical weathering by methane rainfall removes the soluble organic materials, leaving the insoluble organics and water ice behind. These observations support the idea that fluvial processes are active in Titan's equatorial regions.

A closer look at water-related geologic activity on Mars.

Water has supposedly marked the surface of Mars and produced characteristic landforms. To understand the history of water on Mars, we take a close look at key locations with the High-Resolution Imaging Science Experiment on board the Mars Reconnaissance Orbiter, reaching fine spatial scales of 25 to 32 centimeters per pixel. Boulders ranging up to approximately 2 meters in diameter are ubiquitous in the middle to high latitudes, which include deposits previously interpreted as finegrained ocean sediments or dusty snow. Bright gully deposits identify six locations with very recent activity, but these lie on steep (20 degrees to 35 degrees) slopes where dry mass wasting could occur. Thus, we cannot confirm the reality of ancient oceans or water in active gullies but do see evidence of fluvial modification of geologically recent mid-latitude gullies and equatorial impact craters.

Observations of comet 19P/Borrelly by the miniature integrated camera and spectrometer aboard Deep Space 1.

The nucleus of the Jupiter-family comet 19P/Borrelly was closely observed by the Miniature Integrated Camera and Spectrometer aboard the Deep Space 1 spacecraft on 22 September 2001. The 8-kilometer-long body is highly variegated on a scale of 200 meters, exhibiting large albedo variations (0.01 to 0.03) and complex geologic relationships. Short-wavelength infrared spectra (1.3 to 2.6 micrometers) show a slope toward the red and a hot, dry surface (

Genetic studies on Gadaba: a tribal population of Andhra Pradesh, India.

Blood samples were collected from Gadaba, a tribal population of Andhra Pradesh, South India, in order to examine the distribution of blood groups, red cell enzymes and the gammaglobulin polymorphism. Out of 20 genetic markers studied seven protein loci exhibited monomorphism. Surprisingly a case of a rare homozygous variant and twenty-one heterozygous variants at the phosphogluconate dehydrogenase locus (6-PGD), six variants at the phosphohexose isomerase locus (PHI) and a single case of phosphoglucomutase locus 1 (PGM 1) variant were observed. Further, the tribal populations of South India reveal higher frequencies of rare variants than the caste populations. However, the presence of rare variants that are phenotypically neutral may be plausibly due to their high selective value.

Results from the Mars Pathfinder camera.

Images of the martian surface returned by the Imager for Mars Pathfinder (IMP) show a complex surface of ridges and troughs covered by rocks that have been transported and modified by fluvial, aeolian, and impact processes. Analysis of the spectral signatures in the scene (at 440- to 1000-nanometer wavelength) reveal three types of rock and four classes of soil. Upward-looking IMP images of the predawn sky show thin, bluish clouds that probably represent water ice forming on local atmospheric haze (opacity approximately 0.5). Haze particles are about 1 micrometer in radius and the water vapor column abundance is about 10 precipitable micrometers.

Detection of a new variant phenotype of phosphohexose isomerase in the Gadaba tribe of Andhra Pradesh, south India.

A total of 998 unrelated individuals from the Gadaba tribal population of Andhra Pradesh, South India, were screened for red cell phosphohexose isomerase (PHI) by starch gel electrophoresis. A new and hitherto for Andhra Pradesh not yet reported rare variant phenotype was observed: PHI 6-1. The new allele is designated as PHI*6Gadaba.

Red cell 6-phosphogluconate dehydrogenase polymorphism in the Gadaba of Andhra Pradesh (India). Report of new variant phenotypes.

Blood samples from 1000 unrelated, adult individuals of the Gadaba tribal population were screened for 6-phosphogluconate dehydrogenase. We report the occurrence of a new fast moving variant, which is caused by the allele PGD* Gadaba. This allele is reported for the first time among the tribal populations of Andhra Pradesh. Its frequency comes to 0.0115, and it was observed in heterozygous (2.10%) and homozygous (0.10%) conditions.

Red cell enzyme and serum protein types in the Watut Anga of Papua New Guinea.

Historically, the Angan populations of Papua New Guinea have maintained a strong isolation and absorbed limited genes from their neighbours. This lack of intermixing is reflected in their relatively homogeneous cultural, linguistic and genetic profiles. We have determined the electrophoretic variation at 26 red cell enzyme, serum protein and haemoglobin loci in the Watut Anga, a splinter group occupying the Upper Watut Valley of Morobe Province. Their genetic profile reveals the lack of a number-of variants, such as PGM2*10 and MDH*3, known to exhibit high frequencies in other highland populations. The average heterozygosity in the Watut is also much lower when compared with other Papua New Guinean populations. Their present numerical strength notwithstanding, it appears that the Angan populations have experienced population bottlenecks in their evolutionary history which may have accentuated their genetic divergence from other Papua New Guinean populations.

Genetic affinities of oceanic populations based on RFLP and haplotype analysis of genetic loci on three chromosomes.

Restriction fragment length polymorphisms at the renin and factor 13B loci located at chromosome 1q32-1q42 were studied in 14 ethnic groups in the west Pacific region. The allele frequencies were combined with previously described beta-globin and albumin-vitamin D binding protein haplotype frequencies and used to assess genetic affinities among eight major ethnic-geographic groups in this region. These population groups divide into two clusters with Australian Aborigines, Island Melanesians, and Highland Melanesians forming one cluster and east Asians, Southeast Asians, Micronesians, and Polynesians forming the other. The results indicate that Micronesians and Polynesians are derived from populations in Southeast Asia and that they originated independently of the Melanesian populations.

Triton's Geyser-Like Plumes: Discovery and Basic Characterization.

At least four active geyser-like eruptions were discovered in Voyager 2 images of Triton, Neptune's large satellite. The two best documented eruptions occur as columns of dark material rising to an altitude of about 8 kilometers where dark clouds of material are left suspended to drift downwind over 100 kilometers. The radii of the rising columns appear to be in the range of several tens of meters to a kilometer. One model for the mechanism to drive the plumes involves heating of nitrogen ice in a subsurface greenhouse environment; nitrogen gas pressurized by the solar heating explosively vents to the surface carrying clouds of ice and dark partides into the atmosphere. A temperature increase of less than 4 kelvins above the ambient surface value of 38 +/- 3 kelvins is more than adequate to drive the plumes to an 8-kilometer altitude. The mass flux in the trailing clouds is estimated to consist of up to 10 kilograms of fine dark particles per second or twice as much nitrogen ice and perhaps several hundred or more kilograms of nitrogen gas per second. Each eruption may last a year or more, during which on the order of a tenth of a cubic kilometer of ice is sublimed.

Subsurface energy storage and transport for solar-powered geysers on triton.

The location of active geyser-like eruptions and related features close to the current subsolar latitude on Triton suggests a solar energy source for these phenomena. Solidstate greenhouse calculations have shown that sunlight can generate substantially elevated subsurface temperatures. A variety of models for the storage of solar energy in a sub-greenhouse layer and for the supply of gas and energy to a geyser are examined. "Leaky greenhouse" models with only vertical gas transport are inconsistent with the observed upper limit on geyser radius of approximately 1.5 kilometers. However, lateral transport of energy by gas flow in a porous N(2) layer with a block size on the order of a meter can supply the required amount of gas to a source region approximately 1 kilometer in radius. The decline of gas output to steady state may occur over a period comparable with the inferred active geyser lifetime of five Earth years. The required subsurface permeability may be maintained by thermal fracturing of the residual N2 polar cap. A lower limit on geyser source radius of approximately 50 to 100 meters predicted by a theory of negatively buoyant jets is not readily attained.

Energy Sources for Triton's Geyser-Like Plumes.

Four geyser-like plumes were discovered near Triton's south pole in areas now in permanent sunlight. Because Triton's southern hemisphere is nearing a maximum summer solstice, insolation as a driver or a trigger for Triton's geyser-like plumes is an attractive hypothesis. Trapping of solar radiation in a translucent, low-conductivity surface layer (in a solid-state greenhouse), which is subsequently released in the form of latent heat of sublimation, could provide the required energy. Both the classical solid-state greenhouse consisting of exponentially absorbed insolation in a gray, translucent layer of solid nitrogen, and the "super" greenhouse consisting of a relatively transparent solid-nitrogen layer over an opaque, absorbing layer are plausible candidates. Geothermal heat may also play a part if assisted by the added energy input of seasonal cycles of insolation.

Evolution of beta-globin haplotypes in human populations.

The beta-globin haplotypes of 852 chromosomes from 12 populations in the Asia-Pacific region are described. These data are combined with those from other populations in an investigation of the affinities of regional human populations. Both partial maximum-likelihood and distance Wagner methods indicate that Africans are the most divergent group, with the remaining populations branching in the following order: Australian Aborigines, Highland Melanesians, Lowland Melanesians, Indonesians and Micronesians, Polynesians, east Asians, Indians, and Europeans. This pattern of relationship is consistent with that indicated by other data. Analysis of the evolution and distribution of haplotype occurrence provides some limited support for an origin of modern humans in Africa. Otherwise, however, it was not useful in further elucidating the evolutionary history of human populations.

Albumin--vitamin D-binding protein haplotypes in Asian-Pacific populations.

We have determined the various haplotypic combinations between alleles as well as restriction fragment length polymorphisms of two linked genetic markers, albumin and vitamin D-binding protein or group-specific component, in a number of Asian-Pacific populations. Using the partial maximum likelihood method, we constructed a phylogenetic network from the haplotype frequencies to assess relationships among the populations sampled. No systematic linkage disequilibrium was detected between most of the combinations, suggesting a lack of operation of any selection pressure at the two loci. The phylogenetic analysis confirmed the known interrelationships among various populations in the Asian-Pacific region. The Australian aborigines clustered closely with the non-Austronesian-speaking highlanders from Papua New Guinea, as expected. Similarly, the Austronesian-speaking Polynesians, Micronesians, and the Southeast Asians branched off together as a separate group. The position of the Austronesian-speaking Tolais from New Britain with respect to other populations from the Southwest Pacific was anomalous. The Tolais revealed a strong affinity with the Australian aborigines, which is inexplicable. The populations from China formed a tight cluster with other populations from the Asian-Pacific region. Genetic interrelationships of these populations with the white Australians were remote, which is in accordance with the known affinities of various human racial groups.

HLA-DR and -DQ DNA genotyping in insulin-dependent diabetes patients in South India.

Restriction fragment length polymorphisms (RFLPs) of the HLA-DR beta, -DQ alpha, -DQ beta, and -DX alpha genes have been examined in South Indian diabetic patients and controls. The DR. DQ linkage arrangements in South Indians were shown to be different for DR2, DR4, and DRw6 from those commonly seen in Europeans, so that localization of the primary disease-promoting gene in IDDM could be attempted. This study clearly implicates at least one DQ beta allele in the pathogenesis of IDDM.

Red cell enzyme and serum protein gene markers in Fijians.

A total of 332 persons from three localities in the Fiji Islands have been tested for genetic variation in 24 red cell enzyme systems and 4 serum protein systems. Polymorphic variation was present at 7 red cell enzyme loci and 1 serum protein locus. The remaining systems were invariant except for a single individual with a slow variant at the GOT1 locus and another individual with a D variant at the TF locus. The series from Nandi differed significantly from the Lau Islands for gene frequencies in GPT, ACP and ESD, Koro Island differed from the other localities at the PGD locus and from Nandi for ESD. Genetic distance analysis reveals that Lau Islands cluster with Western Samoa, Koro Island with New Caledonia (Vanuatu), with Nandi being separate.

Genetic variants of 6-phosphogluconate dehydrogenase in the Indonesian populations.

Blood samples from 2,091 individuals representing 14 Indonesian populations (11 Austronesian and 3 non-Austronesian speakers) have been tested electrophoretically for 6-phosphogluconate dehydrogenase (6-PGD). Two common alleles, PGDA and PGDC are found in all populations studied, and the phenotype distribution agrees well with the Hardy-Weinberg equilibrium. The PGDC gene frequency varies from as low as 3.5% in the Galelarese to 29% in the Asmat. In general, the PGDC allele seems to decrease in frequency towards the west. A low frequency of PGDC in the Galelarese, a non-Austronesian-speaking population, is thought to be the result of admixture of Austronesian genes, which has not led to language change. In addition to the common alleles, a new variant, PGD A-Lombok, is also described.

Genetic and environmental influence in the epidemiology of noninsulin-dependent diabetes mellitus: a global perspective.

Refinement of the classification of diabetes mellitus to include two major categories, insulin dependent (IDDM) and noninsulin-dependent (NIDDM) and the recent attention paid to the standardization of epidemiological techniques have led to much new information on the epidemiology of the disease. Support for the notion of genetic influence in the development of NIDDM has come from twin studies, but the search for specific genetic markers for NIDDM has been largely unproductive to date. There is increasing scepticism as to the utility of the chlorpropamide-alcohol flush as a genetic marker for NIDDM. The large disparity in the frequency of NIDDM between populations provides indirect support for the genetic hypothesis, as do recent studies of the association between NIDDM and ancestral genetic admixture. Obesity has long been considered a causal factor in the aetiology of NIDDM, though the strength and consistency of this relationship is now being questioned. The strength of the association between obesity and NIDDM has been shown to vary depending on the presence or absence of a family history of the disease. There is further preliminary evidence to suggest that association between obesity and NIDDM may vary in strength between populations, and between the sexes. Little evidence has so far emerged for a role of quantitative or qualitative aspects of diet in the aetiology of NIDDM. This may be due, in part, to the imprecision of current techniques for dietary estimation.(ABSTRACT TRUNCATED AT 250 WORDS)