6,002 research outputs found
Does behavior reflect phylogeny in swiftlets (Aves: Apodidae)? A test using cytochrome b mitochondrial DNA sequences
Swiftlets are small insectivorous birds, many of which nest in caves and are known to echolocate. Due to a lack of distinguishing morphological characters, the taxonomy of swiftlets is primarily based on the presence or absence of echolocating ability, together with nest characters. To test the reliability of these behavioral characters, we constructed an independent phylogeny using cytochrome b mitochondrial DNA sequences from swiftlets and their relatives. This phylogeny is broadly consistent with the higher classification of swifts but does not support the monophyly of swiftlets. Echolocating swiftlets (Aerodramus) and the nonecholocating "giant swiftlet" (Hydrochous gigas) group together, but the remaining nonecholocating swiftlets belonging to Collocalia are not sister taxa to these swiftlets. While echolocation may be a synapomorphy of Aerodramus (perhaps secondarily lost in Hydrochous), no character of Aerodramus nests showed a statistically significant fit to the molecular phylogeny, indicating that nest characters are not phylogenetically reliable in this group
Glacial geology of northern Logan County, south-central North Dakota
Northern Logan County, in south-central North Dakota, is included in two physiogeographic divisions: the southwest fifth is part of the glaciated Missouri Plateau that has integrated drainage and thin drift, and the rest is part of the Missouri Coteau, which has thick drift and nonintegrated drainage. Logan County is underlain by the Cretaceous Pierre Shale, undifferentiated Cretaceous sand, sandstone, and mudstone, and by three surface drifts, the Napoleon (lower part of the Wisconsin Stage), the Long Lake, and the Burnstad (upper part of the Wisconsin Stage) Drifts.
Landforms of the area southwest of the Coteau include ground moraine, outwash plains, outwash topography of high relief, small kames, saltwater channels, and glacial Lake Napoleon strandlines and clay plain. Landforms in the Missouri Coteau part of northern Logan County are dead-ice moraine, Long Lake, Burnstad, and Streeter and moraines, outwash plains, ice-walled lake plains, collapsed outwash topography, disintegration ridges, and several other minor features.
The thin glacier that deposited the Burnstad Drift stagnated in a zone that was at least 6 miles and possibly over 20 miles wide. Radiocarbon dates indicate that it might have taken over 2000 years to melt. The presence of numerous fossil mollusk shells in ice-contact lake sediments indicates that superglacial till was present in large enough amounts to insulate the lakes from the ice and was probably abundant enough to be an important factor in the formation of dead-ice moraine
Tills of Kidder County, North Dakota
Kidder County, located in south-central North Dakota, is completely covered by drift of the Wisconsin stage. Irregular preglacial topography, large amounts or confusing “stagnation” moraine, and a blanket of outwash over much of the county make differentiation of tills of different glacial advances difficult. The purpose of this report is finding ways of lithologically differentiating the tills of the different glacial advances in the county.
Kidder County is covered by drift of two major advances of the Mankato substage, A-1 and B-1 of Flint’s South Dakota designation. A dark brown, sandy, loesslike material covering much of the county probably is the same material overlying carbon 14 dated wood in the southeast part of the county. Yellow loess is exposed in at least four places in the county.
Grain analyses on 55 samples of till from throughout the county showed no significant differences in the size composition of tills of the A-1 and B-1 advances. Fifteen pebble counts failed to show any differences between the tills of the two advances. The field appearances of tills of the two advances do not differ appreciable. However, where two tills crop out in one exposure in the southern part of the county, the lower till is yellower, stickier, and harder than other tills in the county and has small irregular joints coated with iron and manganese oxide. This till is thought to be Tazewell in age. In a second exposure two tills are separated by gravel concentrate which is overlain by less than a foot of loess. These two tills probably belong to the Long Lake and Twin Buttes loops of the A-1 advance of the Mankato substage.
The only way to differentiate tills within the Mankato substage in the end moraine complex of south-central North Dakota is by the topographic expression and stratigraphic relationships of the till sheets. In some cases Mankato and Tazewell tills may be differentiated by secondary changes such as the degree of oxidation and joint coatings. The percentages of sand and the percentages of shale in the coarse sand fraction of samples of till collected from the county were not found to vary appreciably for 15 miles on either side of the contact between the Fox Hills sandstone and the Pierre shale. This helps to strengthen the belief of other workers that only 20-30% of till is locally derived
The Decisions and Ideal Points of British Law Lords
Policy-sensitive models of judicial behaviour, whether attitudinal or strategic, have largely passed Britain by. This article argues that this neglect has been benign, because explanations of judicial decisions in terms of the positions of individual judges fare poorly in the British case. To support this argument, the non-unanimous opinions of British Law Lords between 1969 and 2009 are analysed. A hierarchical item-response model of individual judges’ votes is estimated in order to identify judges’ locations along a one-dimensional policy space. Such a model is found to be no better than a null model that predicts that every judge will vote with the majority with the same probability. Locations generated by the model do not represent judges’ political attitudes, only their propensity to dissent. Consequently, judges’ individual votes should not be used to describe them in political terms
Breaking down the wall: Hope and the dialectical nature of education
This paper will analyze the history of public education and its relationship to the industrial economy, education and curriculum reform literature and policies (both past and present) predominately within the theoretical framework proposed by Henry Giroux. Personal observations and experience as a teacher within this system will be used to provide insight into theoretical paradigms. Implemented programs will be assessed within the historical and theoretical framework outlined above in an effort to determine the impact of post-industrial economic needs on education and the potential for resistance. The predominant method of gathering data will be through literature reviews and within the context of personal observations
The Effects of Foot and Udder Scoring on Cow and Calf Performance
Foot soundness and udder conformation are essential for longevity in beef cattle. The objective of this study was to investigate the effects of foot angle (FA), claw set (CS), teat size (TS) and udder suspension (US) scores on cowherd performance. Data were analyzed for 1,685 observations on Angus-based cows over a four-year period. At weaning FA, CS, TS, and US were evaluated. Scores are based on nine-point scales. A score of one indicates straight pasterns, divergent toes, enlarged bottle shaped teats, and absence of a median suspensory ligament; nine indicates weak pasterns, curled toes, small symmetrical teats, and a tight udder attachment. Cows that exhibited FA and CS scores from four to six were considered acceptable. Cows that exhibited scores outside this range were considered undesirable. Cattle with US and TS scores ranging between four and eight were evaluated. All cows were evaluated for age and performance traits including pre-breeding weight (PBW), pre-breeding body condition score (PBCS), pregnancy rate, calf birthweight (BW), calf weaning weight (WW), calf adjusted weaning weight (AWW), cow body weight at weaning (CWW), weaning body condition score (WBCS), and adjusted weaning performance (AWP). Data were analyzed using the GLIMMIX procedure of SAS. Significance was declared at P ≤ 0.05. Acceptable cows had a WBCS 10.14% greater (P \u3c 0.01) compared to undesirable cows. Acceptable cows possessed an average WBCS of 4.83 compared to 4.34 in undesirable cows. Acceptable cows were 9.50% younger (P = 0.05) than undesirable cows. The mean age for acceptable cows was 4.67 compared to 5.16 in undesirable cows. There were no US differences (P ≥ 0.24) for WBCS. There were no TS differences (P ≥ 0.13) for CWW, WBCS, WW, AWW, and AWP. Cattle with US scores of 4 were on average the oldest (P \u3c 0.01) at 7.75 years of age. Cattle with TS scores of 8 were on average the youngest (P \u3c 0.01) at 3.20 years of age. Cattle with US scores of 4 weaned the heaviest calves (P \u3c 0.01) at 246.92 kg. These results could help predict cow performance based on FA, CS, TS, and US
Domain Generalization by Marginal Transfer Learning
In the problem of domain generalization (DG), there are labeled training data
sets from several related prediction problems, and the goal is to make accurate
predictions on future unlabeled data sets that are not known to the learner.
This problem arises in several applications where data distributions fluctuate
because of environmental, technical, or other sources of variation. We
introduce a formal framework for DG, and argue that it can be viewed as a kind
of supervised learning problem by augmenting the original feature space with
the marginal distribution of feature vectors. While our framework has several
connections to conventional analysis of supervised learning algorithms, several
unique aspects of DG require new methods of analysis.
This work lays the learning theoretic foundations of domain generalization,
building on our earlier conference paper where the problem of DG was introduced
Blanchard et al., 2011. We present two formal models of data generation,
corresponding notions of risk, and distribution-free generalization error
analysis. By focusing our attention on kernel methods, we also provide more
quantitative results and a universally consistent algorithm. An efficient
implementation is provided for this algorithm, which is experimentally compared
to a pooling strategy on one synthetic and three real-world data sets
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