bluuebunny/crossref_metadata_2025_split huggingface dataset:
The difference between the constitutive and facultative skin color does not reflect skin phototype in Asian skin
Authors: Choe Y. B. , Jang S. J. , Jo S. J. , Ahn K. J. , Youn J. I. 
Published: January 2006

Background/purpose: The assessment of the sensitivity of human skin to ultraviolet (UV) radiation is important in the area of phototherapy, photodermatoses, photo‐aging, photo‐carcinogenesis, and photo‐protection. Some reports have shown that quantitatively measured skin color is a good indicator for predicting UV sensitivity to human skin in Caucasians. In this study, our aim was to define the correlation between skin color and the skin phototype assessed by the Fitzpatrick method in Asian brown skin.Methods: A total of 180 medical students with similar life styles were included in this study. Their skin phototype was classified according to the system introduced by Fitzpatrick. Then, using a Minolta Spectrophotometer CM‐2002®, their skin color was determined on the buttocks and forehead. The buttock color was taken as the constitutive skin color, and the forehead color as the facultative skin color. Using these measured values, we compared the skin color with the skin phototype to find their correlation. Also, we investigated whether the difference between the constitutive and facultative skin colors of each individual had a relationship with his or her skin phototype.Results: The constitutive skin color became darker with increasing skin phototype, and this change was statistically significant. As for the facultative skin color, it also became darker with increasing skin phototype, but was less well correlated with the skin phototype than the constitutive skin color. However, the difference between the constitutive and facultative skin colors did not show consistent results in predicting the skin phototype.Conclusion: In this study, we found that the constitutive skin color can be a good indicator of the skin phototype. However, the difference between the constitutive and facultative skin colors of each individual does not give any meaningful information for the assessment of his or her skin phototype in Asian skin.
Habitat and resource use by larval and juvenile fishes in an arid‐land river (Rio Grande, New Mexico)
Authors: PEASE ALLISON A. , JUSTINE DAVIS J. , EDWARDS MELANIE S. , TURNER THOMAS F. 
Published: January 2006

Summary1. Studies of mesic temperate and tropical rivers suggest an important role for floodplain habitats as nursery areas for larval and juvenile fishes. In arid‐land rivers the extent and duration of flooding is diminished and habitats and resources used by larval fishes are poorly known. Our study documented habitat and resource use of larval fishes in the Rio Grande, New Mexico, an arid‐land river.2. Spatial and temporal distribution of larval and juvenile fishes and their inferred microhabitat preferences were studied during spring, summer and autumn, 2003. Stable carbon (13C : 12C) and nitrogen (15N : 14N) isotope ratios were measured to identify nutrient sources and characterise trophic positions of young‐of‐year fishes in this system.3. Some fishes recruited during high flows (in spring), whereas others recruited during low‐flow periods in late summer. Regardless of the timing of reproduction, microhabitats with lower current velocity and higher temperature appeared to serve as vital nursery grounds for Rio Grande fishes. Ephemeral backwaters and disconnected side channels held the highest abundance and diversity of larvae and juveniles.4. Stable isotope analyses revealed that fish larvae obtained carbon predominately from algal production in early summer, but used organic carbon derived from emergent macrophytes as river discharge decreased in mid‐summer. This shift may have been facilitated by microinvertebrate prey that grazed down edible algae and then switched to macrophytes in mid‐summer. Nitrogen isotope ratios did not differ among species or early life stages, suggesting that larval and juvenile fishes use similar food resources, especially when restricted to isolated pools in summer.
Effect of natural atmospheric CO2 fertilization suggested by open‐grown white spruce in a dry environment
Authors: GEOFF WANG G. , CHHIN SOPHAN , BAUERLE WILLIAM L. 
Published: January 2006

AbstractEvidence of an atmospheric CO2‐fertilization effect on radial growth rates was uncovered for open‐grown white spruce in a mixed‐grass prairie of southwestern Manitoba, Canada. Consistent upward trends of the residuals from dendroclimatic models indicated a decreased ability for climatic parameters to predict radial growth. Despite that a similar amount (61%) of the total variation in radial growth index was explained by climate for both young and old trees, residuals from young trees for the period of 1955–1999 demonstrated a stronger upward trend (R2=0.551, P<0.0001) than old trees for the period of 1900–1996 (R2=0.020, P=0.167). Similar to young trees, the residuals from the early growth period (1900–1929) of old trees also demonstrated a stronger upward trend (R2=0.480, P<0.0001) than the period of 1900–1996. Likewise, a comparable period (1970–1999) of young trees also demonstrated a stronger upward trend (R2=0.619, P<0.0001) than the early growth period (1900–1929) of old trees. In addition, postdrought growth response was much stronger for young trees (1970–1999) compared with old trees at the same development stage (1900–1929) (P=0.011) or within the same time period (1970–1999) (P=0.014). There was no difference (P=0.221) in drought recovery between the early (1900–1929) period and the late (1970–1999) period within old trees. Together, our results suggest that (1) open‐grown white spruce trees improved their growth with time at the early developmental stage, and (2) at the same developmental stage, a greater growth response occurred in the late period when atmospheric CO2 concentration, and the rate of atmospheric CO2 increase were both relatively high. While it is impossible to rule out other factors, these results are consistent with expectations for CO2‐fertilization effects.
Tree growth and soil acidification in response to 30 years of experimental nitrogen loading on boreal forest
Authors: HÖGBERG PETER , FAN HOUBAO , QUIST MAUD , BINKLEY DAN , TAMM CARL OLOF 
Published: January 2006

AbstractRelations among nitrogen load, soil acidification and forest growth have been evaluated based on short‐term (<15 years) experiments, or on surveys across gradients of N deposition that may also include variations in edaphic conditions and other pollutants, which confound the interpretation of effects of N per se. We report effects on trees and soils in a uniquely long‐term (30 years) experiment with annual N loading on an un‐polluted boreal forest. Ammonium nitrate was added to replicated (N=3) 0.09 ha plots at two doses, N1 and N2, 34 and 68 kg N ha−1 yr−1, respectively. A third treatment, N3, 108 kg N ha−1 yr−1, was terminated after 20 years, allowing assessment of recovery during 10 years. Tree growth initially responded positively to all N treatments, but the longer term response was highly rate dependent with no gain in N3, a gain of 50 m3 ha−1 stemwood in N2 and a gain of 100 m3 ha−1 stemwood in excess of the control (N0) in N1. High N treatments caused losses of up to 70% of exchangeable base cations (Ca2+, Mg2+, K+) in the mineral soil, along with decreases in pH and increases in exchangeable Al3+. In contrast, the organic mor‐layer (forest floor) in the N‐treated plots had similar amounts per hectare of exchangeable base cations as in the N0 treatment. Magnesium was even higher in the mor of N‐treated plots, providing evidence of up‐lift by the trees from the mineral soil. Tree growth did not correlate with the soil Ca/Al ratio (a suggested predictor of effects of soil acidity on tree growth). A boron deficiency occurred on N‐treated plots, but was corrected at an early stage. Extractable NH4+ and NO3−were high in mor and mineral soils of on‐going N treatments, while NH4+ was elevated in the mor only in N3 plots. Ten years after termination of N addition in the N3 treatment, the pH had increased significantly in the mineral soil; there were also tendencies of higher soil base status and concentrations of base cations in the foliage. Our data suggest the recovery of soil chemical properties, notably pH, may be quicker after removal of the N‐load than predicted. Our long‐term experiment demonstrated the fundamental importance of the rate of N application relative to the total amount of N applied, in particular with regard to tree growth and C sequestration. Hence, experiments adding high doses of N over short periods do not mimic the long‐term effects of N deposition at lower rates.
Bias and variance in model results associated with spatial scaling of measurements for parameterization in regional assessments
Authors: OGLE STEPHEN M. , BREIDT F. JAY , PAUSTIAN KEITH 
Published: January 2006

AbstractModels are central to global change analyses, but they are often parameterized using data that represent only a portion of heterogeneity in a region. This creates uncertainty in the results and constrains the reliability of model inferences. Our objective was to evaluate the uncertainty associated with differential scaling of parameterization data to model soil organic carbon stock changes as a function of US agricultural land use and management. Specifically, we compared analyses in which model parameters were derived from field experimental data that were scaled to the entire US vs. the same data scaled to climate regions within the country. We evaluated the effect of differential scaling on both bias and variance in model results.Model results had less variance by scaling data to the entire country because of a larger sample size for deriving individual parameter values, although there was a relatively large bias associated with this parameterization, estimated at 2.7 Tg C yr−1. Even with the large bias, resulting confidence intervals from the two parameterizations had considerable overlap for the estimated national rate of SOC change (i.e. 77% overlap in those intervals). Consequently, the results were relatively similar when focusing on the uncertainty rather than solely on the mean estimate. In contrast, large biases created less overlap in confidence intervals for the change rates within individual climate regions, compared with the national estimates. For example, the overlap in resulting intervals from the two parameterizations was only 32% for the warm temperate moist region, with a corresponding bias of 3.1 Tg C yr−1.These findings demonstrate that there is a greater risk of making erroneous inferences because of large biases if models are parameterized with broader scale information, such as an entire country, and then used to address impacts at a finer spatial scale, such as sub‐regions within a country. In addition, the study demonstrates a trade‐off between variance and bias in model results that depends on the scaling of data for model parameterization.
Functional and transcriptional profiling of MUTZ‐3, a myeloid cell line acting as a model for dendritic cells
Authors: Larsson Kristina , Lindstedt Malin , Borrebaeck Carl A. K. 
Published: January 2006

SummaryThe incidence of allergy is steadily increasing, but the molecular mechanisms involved in the allergic immune response are still not fully understood. In particular, further investigations focusing on dendritic cells, which are central in orchestrating the immune response, are needed. The objective of this study was to investigate the ability of myeloid leukaemia‐derived cell lines, such as KG‐1, THP‐1 and MUTZ‐3, to serve as in vitro models for dendritic cells. The ability of these cell lines to mature into functional dendritic cells, expressing costimulatory molecules, was assessed by functional and transcriptional profiling and compared with that of monocyte‐derived dendritic cells, which are now used as a standard source of dendritic cells. High‐density microarray analysis was utilized to study the transcriptional activity and kinetics of activation of the differentiated MUTZ‐3 cell line, in response to a cocktail of inflammatory cytokines. The data obtained clearly demonstrate that MUTZ‐3 cells have the ability to induce antigen‐independent proliferation in CD4+ CD45RA+ T cells, whereas KG‐1 and THP‐1 only induced a marginal response. Furthermore, MUTZ‐3 displayed the phenotypic and transcriptional profiles of immature dendritic cells, after differentiation with granulocyte–macrophage colony‐stimulating factor and interleukin‐4. Upon activation with inflammatory cytokines, MUTZ‐3 matured phenotypically and exhibited a gene induction similar to that of monocyte‐derived dendritic cells. This delineation of the cellular and transcriptional activity of MUTZ‐3, in response to maturational stimuli, demonstrates the significance of this cell line as a model for functional studies of inflammatory responses.
Deletion is neither sufficient nor necessary for the induction of peripheral tolerance in mature CD8+ T cells
Authors: Lees Jason R. , Charbonneau Bridget , Swanson Axel K. , Jensen Robert , Zhang JianFeng , Matusik Robert , Ratliff Timothy L. 
Published: January 2006

SummaryPrevious reports have demonstrated clonal deletion of CD8+ T cells during peripheral tolerance induction to tissue antigens. However, direct evidence demonstrating a causal connection between deletion and tolerance has not been reported because of model limitations in which the tissue antigens were expressed in vital organs. Thus, studies were initiated in a mouse model where expression of a membrane‐bound ovalbumin fusion protein (mOVA) was driven by a prostate specific androgen regulated probasin promotor, providing restricted expression in a non‐vital organ where antigen levels can be abrogated through androgen deprivation. Adoptive transfer of mOVA specific CD8+ T cells (OT‐I) was used to assess the development of peripheral tolerance. Proliferation of OT‐I cells was observed, as was partial deletion of transferred OT‐I cells. Although deletion occurred, the long‐term persistence of a stable level of OT‐I cells was observed. Importantly, the persistent OT‐I cells lost antigen responsiveness within 3 weeks of transfer. Castration resulted in loss of high‐level prostate mOVA expression, with a resultant abrogation of tolerance induction, but surprisingly did not affect the deletion rate of OT‐I cells. In contrast, abrogation of deletion through the adoptive transfer of OT‐I cells from third generation CD95‐deficient mice had no effect on tolerance induction. These data demonstrate the necessity for continued expression of tissue antigen throughout the establishment of peripheral tolerance. Furthermore, these findings demonstrate that deletion is neither sufficient nor required for CD8+ T‐cell tolerance to tissue antigens, suggesting that regulatory events independent of deletion are necessary for peripheral tolerance induction to prostate antigens.
Gonochorism vs. hermaphroditism: relationship between life history and fitness in three species of Ophryotrocha (Polychaeta: Dorvilleidae) with different forms of sexuality
Authors: PREVEDELLI DANIELA , N'SIALA GLORIA MASSAMBA , SIMONINI ROBERTO 
Published: January 2006

Summary

The relationships between life history, fitness and sexuality, together with their ecological and evolutionary significance, has been analysed comparing the main life‐history traits and demography in three closely related species belonging to the genus Ophryotrocha. The species are: the gonochoristic O. labronica, the simultaneous hermaphrodite O. diadema and the protandrous hermaphrodite O. puerilis.
Survivorship and reproductive data were collected weekly and were used to construct life tables and population projection matrices for each species and compare life‐history characteristics. Elasticity, life‐table response and decomposition analyses were performed to examine the relative contribution of fecundity and survivorship to differences in λ between species.
The gonochoristic and hermaphroditic species differ in all the main life‐history parameters and also in demographic characteristics. In particular the value of λ, used commonly to express fitness, is markedly higher in the gonochoristic species while in terms of fitness simultaneous and sequential hermaphroditism are very similar. In the genus Ophryotrocha gonochorism currently represents the most widespread condition, being characteristic of the majority of the known species in the genus.
Given the demographic advantage ensured by gonochorism, it remains be understood why some species have retained simultaneous hermaphroditism and one has evolved a sequential type hermaphroditism; the most probable hypothesis is correlated with the density of the species in natural habitats.
Unrealistic animal movement rates as behavioural bouts: a reply
Authors: JOHNSON CHRIS J. , PARKER KATHERINE L. , HEARD DOUGLAS C. , GILLINGHAM MICHAEL P. 
Published: January 2006

Summary

Johnson et al. (Journal of Animal Ecology, 2002, 71, 225–235) proposed a technique for stratifying the movements of ungulates into small‐ and large‐scale behaviours. They identified movement paths for woodland caribou and fitted a nonlinear curve to the log‐frequency of movement rates. They assumed that slow small‐scale movements were correlated with foraging activities in patches and faster large‐scale movements occurred when caribou moved between patches.
Nams (Journal of Animal Ecology, 2006, 75, 298–302) reviewed the assumptions and tested the technique presented by Johnson et al. (2002). Simulated animal movements resulted in rates inconsistent with the data of Johnson et al. (2002) and the distribution necessary to fit the nonlinear curve. Nams (2006) challenged animal movement as suitable for the technique and concluded that sampling interval would confound results.
We evaluated Nams's (2006) criticisms with movement data collected for caribou, moose and mountain goat. All three species demonstrated the required distribution of movement rates and sampling interval had little influence on the criterion used to identify scales of movement for a range of woodland caribou data. In addition, we tested the sensitivity of the curve‐fitting model to the width of the frequency interval for the log‐frequency plot of movement rates. We noted bias in the rate criterion, but the scalar relationship was consistent among interval widths.
The discrepancy in movement data presented by Nams (2006) and Johnson et al. (2002) is likely the result of different movement processes. The movements of simulated animals did not encompass the full range of behaviours typically observed for ungulates. Our analyses and those of Nams (2006) provide little evidence to universally reject the nonlinear curve‐fitting model and the results of Johnson et al. (2002). However, we caution against blind application of the technique, as not all movement processes are suitable and the scale of movement must be consistent with the scale of the behaviour.
Nutritional value of cannibalism and the role of starvation and nutrient imbalance for cannibalistic tendencies in a generalist predator
Authors: MAYNTZ DAVID , TOFT SØREN 
Published: January 2006

Summary

Cannibalism is considered an adaptive foraging strategy for animals of various trophic positions, including carnivores. However, previous studies on wolf spiders have questioned the high nutritional value of cannibalism. We therefore analysed two different aspects of nutritional quality of conspecifics in the wolf spider Pardosa prativaga: their value for survival, growth and development; and the growth efficiency of feeding on conspecifics. We also measured the propensity for cannibalistic attacks and the consumption rate of conspecifics in an experiment where hunger level and nutrient balance were manipulated. In all experiments, cannibalism was compared with predation on fruit flies as control prey.
The growth experiment gave ambiguous results regarding the nutritional quality of conspecifics. Spiders on pure cannibalistic diets split into two distinct groups, one performing much better and the other much worse than spiders on fruit fly diets. We discuss the possibility that the population is dimorphic in its cannibalistic propensity, with the latter group of individuals showing a high level of inhibition against cannibalistic attacks in spite of a high nutritional value of cannibalism.
The food utilization experiment confirmed the high nutritional quality of conspecifics, as cannibalistic spiders had the same growth rate as spiders fed insect prey in spite of a much lower consumption rate.
Inhibition against cannibalistic attacks was demonstrated in medium‐sized juveniles: only half of the spiders attacked a prescribed victim of 50% the size of their opponents, and the latency for those that did attack was more than half an hour, compared with a few minutes for spiders fed fruit flies.
Nutrient‐imbalanced spiders utilized an alternative insect diet less efficiently than balanced spiders, whereas no difference was present in efficiency of utilizing conspecifics. This result indicates that spiders can remedy at least part of a nutrient imbalance through cannibalism.
As spiders can escape nutritional imbalance as well as restore energy reserves through cannibalism, we predicted both nutrient imbalance and hunger to stimulate cannibalism. This prediction was confirmed only with respect to hunger. Nutrient‐imbalanced spiders had reduced cannibalistic consumption, perhaps due to lowered predatory aggressiveness as a result of bad condition.
Evaluating the performance of species richness estimators: sensitivity to sample grain size
Authors: HORTAL JOAQUÍN , BORGES PAULO A. V. , GASPAR CLARA 
Published: January 2006

Summary

Fifteen species richness estimators (three asymptotic based on species accumulation curves, 11 nonparametric, and one based in the species–area relationship) were compared by examining their performance in estimating the total species richness of epigean arthropods in the Azorean Laurisilva forests. Data obtained with standardized sampling of 78 transects in natural forest remnants of five islands were aggregated in seven different grains (i.e. ways of defining a single sample): islands, natural areas, transects, pairs of traps, traps, database records and individuals to assess the effect of using different sampling units on species richness estimations.
Estimated species richness scores depended both on the estimator considered and on the grain size used to aggregate data. However, several estimators (ACE, Chao1, Jackknife1 and 2 and Bootstrap) were precise in spite of grain variations. Weibull and several recent estimators [proposed by Rosenzweig et al. (Conservation Biology, 2003, 17, 864–874), and Ugland et al. (Journal of Animal Ecology, 2003, 72, 888–897)] performed poorly.
Estimations developed using the smaller grain sizes (pair of traps, traps, records and individuals) presented similar scores in a number of estimators (the above‐mentioned plus ICE, Chao2, Michaelis–Menten, Negative Exponential and Clench). The estimations from those four sample sizes were also highly correlated.
Contrary to other studies, we conclude that most species richness estimators may be useful in biodiversity studies. Owing to their inherent formulas, several nonparametric and asymptotic estimators present insensitivity to differences in the way the samples are aggregated. Thus, they could be used to compare species richness scores obtained from different sampling strategies. Our results also point out that species richness estimations coming from small grain sizes can be directly compared and other estimators could give more precise results in those cases. We propose a decision framework based on our results and on the literature to assess which estimator should be used to compare species richness scores of different sites, depending on the grain size of the original data, and of the kind of data available (species occurrence or abundance data).