Discrepancies In Trends Research Articles

Flame retardants (PBDEs) in marine turtles, dugongs and seafood from Queensland, Australia

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in numerous products. These compounds have been found to enter the marine environment where they have the potential to bioaccumulate in biota. Limited information is currently available concerning the levels of PBDEs in Australian marine wildlife. This study presents baseline information on PBDE levels in a variety of marine species from Queensland, Australia and considers the influence of species-specific factors on contaminant levels and tissue distribution in marine turtles. Overall, the PBDE levels measured in this study are relatively low compared to marine biota from the northern hemisphere, indicating low level input into the marine system of Queensland. This is in general agreement with global estimates which suggest low PBDE usage in Australia. Previous studies, however, have found relatively high PBDE levels in Australian human milk and sera. This discrepancy in contamination trends between terrestrial and marine biota suggests that future transport of PBDEs may occur to the marine system in Australia.

A multi‐year comparison of lower stratospheric temperatures from CHAMP radio occultation data with MSU/AMSU records

Long‐term upper air temperature records have been established by different groups with considerable effort from radiosonde data and from satellite based (Advanced) Microwave Sounding Unit (MSU/AMSU) measurements, the latter providing information on layer‐average stratospheric and tropospheric brightness temperatures. Comparisons of the temperature series show discrepancies not only with respect to radiosonde data but also between MSU data sets stemming from different retrievals. In this context the Global Navigation Satellite System radio occultation (RO) technique offers new possibilities by providing high quality observations of the atmosphere in an active limb sounding mode. RO temperature climatologies have been constructed at the WegCenter/UniGraz based on RO observations of the CHAllenging Minisatellite Payload for geoscientific research (CHAMP) satellite since September 2001, and based on a few months of RO data from other satellite missions (SAC‐C, GRACE, COSMIC). Focusing on the MSU lower stratosphere channel (TLS), synthetic TLS temperatures were calculated by applying global weighting functions to zonal‐mean monthly mean RO temperature climatology profiles for September 2001–December 2006. These synthetic CHAMP TLS temperatures were compared to recent MSU TLS records from the University of Alabama in Huntsville (UAH, USA) and from Remote Sensing Systems (RSS, USA), as well as to synthetic TLS temperatures from HadAT2 radiosonde data (Hadley Centre/MetOffice, UK) and ECMWF (European Centre for Medium‐Range Weather Forecasts) analyses. In terms of TLS temperature anomalies, overall very good agreement of CHAMP temperature anomalies with UAH, RSS, and ECMWF anomalies was found for intra‐annual variability (RMS difference of de‐trended data <0.1 K globally, 0.1 K in the tropics, <0.25 K in the extratropics), while HadAT2 anomalies show larger differences (factor of two globally and more in the extratropics). Regarding 2001–2006 trends, UAH and RSS exhibit a statistically significant cooling trend difference to CHAMP globally (−0.30 to −0.36 K/5 yrs), stemming mainly from the tropics (−0.40 to −0.42 K/5 yrs), while in the extratropics the cooling trend differences are not significant. The contribution of known error sources regarding the RO data and the related synthetic‐MSU computation procedure is about an order of magnitude smaller than these trend differences. Resolution of the trend discrepancy thus requires either additional, so far overlooked, sources of error in the RO TLS record or the presence of currently unresolved biases in the MSU records. SAC‐C, GRACE, and COSMIC TLS temperatures closely match CHAMP temperatures, indicating the consistency and homogeneity of the RO data series. The results underpin the benefit of having multiple independent estimates of the same variable from different instruments for detecting residual weaknesses in otherwise high‐quality climate records. Continued inter‐comparison, and exploiting the traceability of the RO data to the universal time standard (UTC), then enables us to further reduce the uncertainty in the climate records in absolute terms.

Discrepancies Between Score Trends from NAEP and State Tests: A Scale‐Invariant Perspective

State test score trends are widely interpreted as indicators of educational improvement. To validate these interpretations, state test score trends are often compared to trends on other tests such as the National Assessment of Educational Progress (NAEP). These comparisons raise serious technical and substantive concerns. Technically, the most commonly used trend statistics—for example, the change in the percent of proficient students—are misleading in the context of cross‐test comparisons. Substantively, it may not be reasonable to expect that NAEP and state test score trends should be similar. This paper motivates then applies a “scale‐invariant” framework for cross‐test trend comparisons to compare “high‐stakes” state test score trends from 2003 to 2005 to NAEP trends over the same period. Results show that state trends are significantly more positive than NAEP trends. The paper concludes with cautions against the positioning of trend discrepancies in a framework where only one trend is considered “true.”

Provincialism in trends and high frequency changes in the northwest North Atlantic during the Holocene

In the present paper, we report on micropaleontological (dinocysts) and isotopic ( 18O and 13C in foraminifers) analyses performed in Holocene sediments from fifteen cores raised from the central and northwest North Atlantic. Sea-surface temperature (SST), sea-surface salinity (SSS), thus potential density, and sea-ice cover are reconstructed based on dinocyst assemblages. After proper calibration, oxygen isotope data on the mesopelagic foraminifer Neogloboquadrina pachyderma left coiled (Npl) are converted into potential density values deeper in the water column, thus allowing documentation of vertical density gradients and identification of intervals favourable for winter convection to occur with formation of intermediate Labrador Sea Water (LSW). The most important findings from this study include: (1) the existence of an early-mid Holocene thermal optimum with positive anomalies up to 6 °C above present along the main SW–NE axis of the North Atlantic Current, but no significant SST maximum at most sites along eastern Canadian margins; (2) the evidence for larger than present amplitude of annual SSTs during the early Holocene, thus for a stronger seasonality; (3) minimum sea-ice cover from 11 500 to 6000 cal years BP, and a slight increase of sea-ice variability, and average seasonal duration of 0.5 to 1 month per year afterwards; (4) variable SSS during the entire Holocene, suggesting changes in the routing and rates of freshwater–meltwater discharges from the Arctic and eastern Canada; (5) the setting of conditions compatible with LSW production after 8 ka only, and likely a more steady production during the late Holocene; (6) an overall trend for a potential density increase of the Labrador Sea, throughout the Holocene, matching a decreasing trend eastward, thus suggesting a progressive enhancement of the western branch of the Atlantic Meridional Overturning with respect to its northeastern route; and (7) indication of maximum production and fast dispersal of LSW in the entire North Atlantic during recent times only, as suggested by linearly-converging δ 18O-values of Npl from all sites, towards its modern relatively homogeneous composition (∼ 2.5/2.6‰). The overall picture of the Holocene North Atlantic arising from this study is that of a basin marked by a strong regionalism with large discrepancies in hydrographical trends and high frequency oscillations, at least partly controlled by freshwater–meltwater routes and rates of export from the Arctic.

An intercomparison of trends in surface air temperature analyses at the global, hemispheric, and grid‐box scale

The IPCC Third Assessment Report noted that three major temperature analyses exhibited different warming rates over global land areas since 1976. This paper attempts to explain these trend discrepancies by quantifying the sensitivity of global, hemispheric, and grid‐box trends to both the spatial averaging technique and the underlying station network. The Global Historical Climatology Network (GHCN) analysis and the Climatic Research Unit (CRU) analysis have comparable trends when the same approach is used to compute the global time series, and since the mid‐1970s the rate of warming in both is as much as a third greater than in the Goddard Institute for Space Studies (GISS) analysis. On the hemispheric scale, GHCN and CRU have similar trends regardless of the gridding approach, whereas GISS again has less warming in recent decades (particularly in the Southern Hemisphere). GHCN and CRU also exhibit reasonable agreement at the grid‐box level during the period 1976–2003.

Zonal asymmetries in middle atmosphere temperatures

Zonal asymmetries are frequently seen in stratospheric temperature or trace gas fields as surf zones, streamers, filaments etc. They are also seen as very small-scale fluctuations, the intensity of which varies with longitude. Similar structures might be expected in the mesosphere as well, and several examples have recently been found. CRISTA 1 large-scale data are presented that indicate a surf zone in the middle mesosphere at the beginning of winter. Very small-scale data are shown from the CRISTA 2 mission. Mesospheric variability is found to be high at all altitudes, latitudes, and longitudes. There are considerable non-zonal structures in these fluctuations. (The duration of the Crista missions was about one week each.) Zonal asymmetries have been known for a long time from comparisons of ground stations measuring the same parameter in the mesosphere/lower thermosphere. As an example, upper mesosphere temperatures derived from OH ∗ emissions are compared here for Wuppertal and Moscow (Zvenigorod), which are about 2000 km apart. A systematic and substantial difference in temperature is obtained, with higher temperatures at Wuppertal than at Moscow. The difference appears to follow the solar cycle: it is small at solar maximum and large (up to 28 K) at solar minimum. The reason for this surprising behavior is as yet unknown. The Moscow and Wuppertal temperatures have also been analyzed for long-term trends: a trend discrepancy between the two stations is not seen in the data interval common to the two stations.

Decreasing incidence of both major histologic subtypes of gastric adenocarcinoma--a population-based study in Sweden.

While the overall incidence of gastric cancer has fallen, presumably to a large extent in parallel with Helicobacter pylori infection, the occurrence of the diffuse histologic type is thought to have remained more stable, questioning the aetiologic role of H. pylori. We have analysed the incidence of the intestinal and diffuse types separately, while considering subsite (cardia/non-cardia). With an extensive prospective effort we identified all incident cases of gastric adenocarcinoma (n = 1337) in a well-defined Swedish population (1.3 million) 1989–1994. Tumours were uniformly classified histologically and topographically. Subgroup-specific incidence rates were computed and modelled using multivariate logistic regression. Site-specific trends were clearly discrepant. The overall incidence of adenocarcinoma distal to the gastric cardia declined by 9% (95% confidence interval 6–12%) per year, while cardia cancer remained stable. Thus, the feared rise in cardia cancer could not be confirmed despite clear site-specific trend discrepancies. The intestinal type predominated, especially in high-risk areas, while diffuse tumours prevailed among young patients and women. Both main histologic types of gastric adenocarcinoma declined markedly, at similar rapidity, and with no significant trend differences between the intestinal and diffuse types, even after multivariate adjustments. Our results are consistent with an aetiologic role of environmental factors including H. pylori also for diffuse-type gastric cancers. © 2000 Cancer Research Campaign

A Model of Northern Pintail Productivity and Population Growth Rate

Our objective was to synthesize individual components of reproductive ecology into a single estimate of productivity and to assess the relative effects of survival and productivity on population dynamics. We used information on nesting ecology, renesting potential, and duckling survival of northern pintails (Anas acuta) collected on the Yukon-Kuskokwim Delta (Y-K Delta), Alaska, 1991-95, to model the number of ducklings produced under a range of nest success and duckling survival probabilities. Using average values of 25% nest success, 11% duckling survival, and 56% renesting probability from our study population, we calculated that all young in our population were produced by 13% of the breeding females, and that early-nesting females produced more young than later-nesting females. Further, we calculated, on average, that each female produced only 0.16 young females/nesting season. We combined these results with estimates of first-year and adult survival to examine the growth rate (λ) of the population and the relative contributions of these demographic parameters to that growth rate. Contrary to aerial survey data, the population projection model suggests our study population is declining rapidly (λ = 0.6969). The relative effects on population growth rate were 0.1175 for reproductive success, 0.1175 for first-year survival, and 0.8825 for adult survival. Adult survival had the greatest influence on λ for our population, and this conclusion was robust over a range of survival and productivity estimates. Given published estimates of annual survival for adult females (61%), our model suggested nest success and duckling survival need to increase to approximately 40% to achieve population stability. We discuss reasons for the apparent discrepancy in population trends between our model and aerial surveys in terms of bias in productivity and survival estimates.

Skin-Friction Predictions in a Crossing-Shock Turbulent Interaction

This work addresses some dife culties in the computation of skin-friction loads caused by shock wave/ turbulent boundary-layer interactions in high-speed inlets. Of particular interest is the accuracy of k-« based models for Cf prediction in the separated three-dimensional e owe eld induced by a symmetric double-e n geometry at Mach 4. A compressibility correction and two length-scale limiting procedures are investigated. A strong correlation is observed between coherent trends in Cf and the e owe eld structure near the surface. On the symmetry plane, all modie cations improve predictions over the baseline model, but only in the initial interaction region. The downstream e ow exhibits high gradients and manifests a central line of three-dimensional attachment straddled by longitudinal vortices. This physical complexity results in uniformly poor predictions. Off the symmetry plane, however, the e ow features are relatively simpler, and remarkably good agreement is observed with experiment, particularly with the application of a compressibility correction. Some Cf trend discrepancies between experiment and computation are shown to be associated with a displaced development of mean structures in the computations.

See How They Read: Comprehension Monitoring of L1 and L2 Readers

This paper illustrates the comprehension-monitoring process used by first and second language readers of English as they read expository prose. The think-aloud protocols of 25 college freshmen were collected. Sixteen (8 L1 and 8 L2 readers) were classified as proficient, 9 as nonproficient (3 L1 and 6 L2 readers). The monitoring process is discussed with respect to two specific problems: one involving a search for a referent, the other, a vocabulary problem. Three phases and six specific steps are defined: evaluation phase (problem recognition and problem source identification), action phase (strategic plan and action/ solution attempt), and checking phase (check and revision). The responses indicated that monitoring was most thorough with the referent problem when the problem was explicitly signaled. The process was somewhat truncated with the vocabulary problem. Proficient L2 readers performed similarly to proficient L1 readers; less proficient L2 readers performed similarly to less proficient L1 readers. Although the general trends shown in L1 research were supported, there were some discrepancies in developmental trends. Caution is advised in applying the results of L1 research to L2 readers. Reading is such a hidden process that it often goes unnoticed in the language classroom. Still we know much more about reading in both a first and a second language than we did 15 years ago. We have ceased debating whether reading is a bottom-up, languagebased process or a top-down, knowledge-based process. Most people now accept that the two processes interact (Carrell, Devine, & Eskey, 1988; Grabe, 1991; Rumelhart, 1977; Stanovich, 1980). We now also appreciate the influence of background knowledge on both Li and L2 readers (e.g., Adams & Collins, 1985; Anderson & Pearson, 1984; Carrell, 1983, 1988; Carrell & Eisterhold, 1983; Steffensen, Joag-dev, & Anderson, 1979). And, furthermore, we

The Miocene bending of Southwest Japan: new 39Ar/ 40Ar and microtectonic constraints from the Nagasaki schists (western Kyushu), an extension of the Sanbagawa high-pressure belt

In the westernmost part of Kyushu, the Nagasaki metamorphics (also observed in Amakusa) consist of oceanic sediments and fragments of ophiolite. These rocks underwent a high-pressure metamorphism followed by an increase in temperature up to the upper greenschist facies prior to the Late Cretaceous. Microtectonic and kinematic analyses indicate a synmetamorphic ductile shear from south to north. Dating of glaucophane, phengite and biotite by 39Ar/ 40Ar method suggests that the peak of metamorphism and the related deformation occurred approximately 90–95 Ma ago (i.e. Cenomanian), but a resetting by an Oligo-Miocene tectonic event is also evidenced. Due to discontinuous exposures, the metamorphic rocks of Kyushu cannot be continuously traced to the metamorphic belts of Honshu and Shikoku. Nonetheless the lithostratigraphy, metamorphic environment, radiometric data and deformation style strongly support a correlation of the Nagasaki metamorphics with the Green Schist nappe of Southwest Japan which underwent the Late Jurassic/early Cretaceous high-pressure Sanbagawa metamorphism. Such a correlation implies that (1) in the Amakusa area, the Nagasaki metamorphics form a window north of a meta-olistostrome that belongs to the Tanba-Ryoke zone; (2) the trend discrepancy of the stretching lineations between West Kyushu and Southwest Japan is in agreement with a clockwise rotation of the latter with respect to the former assumed to be fixed to Eurasia. Such a bending occurred after Paleogene times, probably during the opening of the Sea of Japan.