2,695 research outputs found
Geographically variable biotic interactions and implications for species ranges
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordThe challenge: Understanding how biotic interactions affect speciesâ geographic ranges, biodiversity patterns, and ecological responses to environmental change is one of the most pressing challenges in macroecology. Extensive efforts are underway to detect signals of biotic interactions in macroecological data. However, efforts are limited by bias in the taxa and spatial scale for which occurrence data are available, and by difficulty in ascribing causality to co-occurrence patterns. Moreover, we are not necessarily looking in the right places: analyses are largely ad hoc, depending on data availability, rather than focusing on regions, taxa, ecosystems, or interaction types where biotic interactions might affect speciesâ geographic ranges most strongly.
Unpicking biotic interactions: We suggest that macroecology would benefit from recognising that abiotic conditions alter two key components of biotic interaction strength: frequency and intensity. We outline how and why variation in biotic interaction strength occurs, explore the implications for speciesâ geographic ranges, and discuss the challenges inherent in quantifying these effects. In addition, we explore the role of behavioural flexibility in mediating biotic interactions to potentially mitigate impacts of environmental change.
New data: We argue that macroecology should take advantage of âindependentâ data on the strength of biotic interactions measured by other disciplines, in order to capture a far wider array of taxa, locations and interaction types than are typically studied in macroecology. Data on biotic interactions are readily available from community, disease, microbial, and parasite ecology, evolution, palaeontology, invasion biology, and agriculture, but most are yet to be exploited within macroecology
Broader niches revealed by fossil data donât reduce estimates of range loss and fragmentation of African montane trees
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.The data supporting the results already exists and is freely available in the Global Biodiversity Information Facility (GBIF) and the African Pollen Database (APD).Aim: Many speciesâ climate tolerances are broader than those estimated from current native ranges. Indeed, some Afromontane treesâ niches are up to 50% larger after incorporating fossil data. This expansion could reduce estimates of speciesâ future range loss due to climate change but also implies strong non-climatic limitations on speciesâ current ranges. One such limitation is land use, which fossil data suggest influences Afromontane tree distribution, preventing these trees from occupying warmer conditions than they currently do. We aim to assess the degree to which the broader climatic tolerances revealed by fossil data buffers projected range loss from climate and land use for Afromontane trees.
Location: Africa.
Time period: Last 21,000 years.
Major taxa studied: Afromontane trees.
Methods: We used species distribution models informed by both current and fossil distributions to project future ranges under climate and land-use projections. Results: We found that projected range reductions are only slightly ameliorated by incorporating fossil distributions and these improvements diminish further under severe land use or climate change scenarios. Taxa that are less impacted by climate are more impacted by intense land use. Depending on the severity of climate and land use, the geographic extent of Afromontane tree speciesâ ranges will contract by 40-85% and the trees will completely be lost from large portions of Africa. We projected that the surviving speciesâ ranges will become increasingly fragmented.
Main conclusions: Maintaining Afromontane ecosystems will require mitigation of both climate and land-use change and protecting areas to optimize connectivity. Our findings caution that species with climate tolerances broader than their current range might not necessarily fare better under strong changes in climate or land use
Properties of HxTaS2
The preparation of Hx TaS2 (0 \u3c x \u3c 0.87) is described. The compounds are only marginally stable at room temperature, slowly evolving H2S and H2 (and possibly Hp in air). Magnetic susceptibility data show that a low temperature transformation in 2H ... TaS2 (at soâąK) is suppressed with the addition of hydrogen, and· at the same time the superconducting transition temperature T c rises from 0.8 to ~4.2âąK at x = 0.11. Heat capacity measurements near this concentration show the superconductivity to be a bulk effect. Finally, by correlation of this data with susceptibility and T c measurements in other intercalation compounds, we suggest that the rise of T c (at low electron transfer) is due to suppression of the low temperature transformation and not due to an excitonic mechanism of superconductivity
A clinically feasible multiplex proteomic immunoassay as a novel functional diagnostic for pancreatic ductal adenocarcinoma
Socioeconomic risk, parenting during the preschool years and child health age 6 years
Parentâchild relationships and parenting processes are emerging as potential life course
determinants of health. Parenting is socially patterned and could be one of the factors responsible for
the negative effects of social inequalities on health, both in childhood and adulthood. This study tests
the hypothesis that some of the effect of socioeconomic risk on health in mid childhood is transmitted
via early parenting. Methods: Prospective cohort study in 10 USA communities involving 1041 mother/
child pairs, selected at birth at random with conditional sampling. Exposures: income, maternal
education, maternal age, lone parenthood, ethnic status and objective assessments of mother child
interaction in the first 4 years of life covering warmth, negativity and positive control. Outcomes:
motherâs report of childâs health in general at 6 years. Modelling: multiple regression analyses with
statistical testing of mediational processes. Results: All five indicators of socioeconomic status (SES) were
correlated with all three measures of parenting, such that low SES was associated with poor parenting.
Among the measures of parenting maternal warmth was independently predictive of future health, and
among the socioeconomic variables maternal education, partner presence and âother ethnic groupâ
proved predictive. Measures of parenting significantly mediated the impact of measures of SES on child
health. Conclusions: Parenting mediates some, but not all of the detectable effects of socioeconomic
risk on health in childhood. As part of a package of measures that address other determinants,
interventions to support parenting are likely to make a useful contribution to reducing childhood
inequalities in health
Exhaust System Gas-Dynamics in Internal Combustion Engines
ABSTRACT The sensitivity of engine performance to gas-dynamic phenomena in the exhaust system has been known for around 100 years but is still relatively poorly understood. The nonlinearity of the wave-propagation behaviour renders simple empirical approaches ineffective, even in a single-cylinder engine. The adoption of analytical tools such as engine-cyclesimulation codes has enabled greater understanding of the tuning mechanisms but for multi-cylinder engines has required the development of accurate models for pipe junctions. The present work examines the propagation of pressure waves through pipe junctions using shock-tube rigs in order to validate a computational model. Following this the effects of exhaustsystem gas dynamics on engine performance are discussed using the results from an engine-cycle-simulation program based on the equations of one-dimensional compressible fluid flow. NOMENCLATURE a speed of sound c propagation speed p pressure u particle speed Îș ratio of speed heats Subscripts 0 conditions in undisturbed ga
Phosphorylated c-Src in the nucleus is associated with improved patient outcome in ER-positive breast cancer
Elevated c-Src protein expression has been shown in breast cancer and <i>in vitro</i> evidence suggests a role in endocrine resistance. To investigate whether c-Src is involved in endocrine resistance, we examined the expression of both total and activated c-Src in human breast cancer specimens from a cohort of oestrogen receptor (ER)-positive tamoxifen-treated breast cancer patients. Tissue microarray technology was employed to analyse 262 tumour specimens taken before tamoxifen treatment. Immunohistochemistry using total c-Src and activated c-Src antibodies was performed. KaplanâMeier survival curves were constructed and log-rank test were performed. High level of nuclear activated Src was significantly associated with improved overall survival (<i>P</i>=0.047) and lower recurrence rates on tamoxifen (<i>P</i>=0.02). Improved patient outcome was only seen with activated Src in the nucleus. Nuclear activated Src expression was significantly associated with node-negative disease and a lower NPI (<i>P</i><0.05). On subgroup analysis, only ER-positive/progesterone receptor (PgR)-positive tumours were associated with improved survival (<i>P</i>=0.004). This shows that c-Src activity is increased in breast cancer and that activated Src within the nucleus of ER-positive tumours predicts an improved outcome. In ER/PgR-positive disease, activated Src kinase does not appear to be involved in <i>de novo</i> endocrine resistance. Further study is required in ER-negative breast cancer as this may represent a cohort in which it is associated with poor outcome
Going beyond defining: Preschool educators\u27 use of knowledge in their pedagogical reasoning about vocabulary instruction
Previous research investigating both the knowledge of early childhood educators and the support for vocabulary development present in early childhood settings has indicated that both educator knowledge and enacted practice are less than optimal, which has grave implications for children\u27s early vocabulary learning and later reading achievement. Further, the nature of the relationship between educators\u27 knowledge and practice is unclear, making it difficult to discern the best path towards improved knowledge, practice, and children\u27s vocabulary outcomes. The purpose of the present study was to add to the existing literature by using stimulated recall interviews and a grounded approach to examine how 10 preschool educators used their knowledge to made decisions about their moment-to-moment instruction in support of children\u27s vocabulary development. Results indicate that educators were thinking in highly context-specific ways about their goals and strategies for supporting vocabulary learning, taking into account important knowledge of their instructional history with children and of the children themselves to inform their decision making in the moment. In addition, they reported thinking about research-based goals and strategies for supporting vocabulary learning that went beyond simply defining words for children. Implications for research and professional development are discussed
Rekruitment Tropical Box Mussels, Septifer Bilocularis In Tiwoho Coastal Area
The purpose of this study was to determine 1) the types of substrates on which Septiver attached, and 2) the number of tropical boxes mussel recruits at different size aggregation. The meter was placed on one side of the mussel aggregation, and it was pulled up to the other side through the middle of the mussel aggregation. There were two different sizes of aggregation, namely small aggregation with a diameter of 5-25 cm, and large aggregation with a diameter > 1 meter. Aggregation samples were carried out by placing a core with a diameter of 10 cm in the center of the small mussel aggregation, then at the edge and the middle position of the large aggregation. All aggregation in the core was removed and inserted into the labeled sample plastic. The sampling was applied 4 times on different mussel aggregations, as replication. The results show that young mussels (recruiters) are attached to algae stems, mussel byssus, and dead hard coral. The number of mussel recruits was square-root transformed to obtain homogeneity data, before being tested using One-Way Analysis of Variance. The results showed that the recruitment of Septifer was influenced by the size of the aggregation (P 0.05). Discussion of different factors affecting attachment occurs.Keywords: box mussel; Septifer; recruit; aggregation; larva; TiwohoAbstrakTujuan penelitian ini adalah untuk mengetahui 1) jenis-jenis substrat yang menjadi tempat menempel kerang mudah Septiver, dan 2) jumlah rekruit kerang kotak tropis pada ukuran aggregasi kerang yang berbeda. Pengukuran ukuran aggregasi kerang dilakukan dengan meletakkan meteran pada salah satu sisi aggregasi kerang, selanjutnya meteran ditarik sampai ke sisi yang lain melewati bagian tengah aggregasi kerang. Ada 2 jenis ukuran aggregasi, yaitu aggregasi kecil dengan ukuran diameter aggregasi 5 â 25 cm, dan aggregasi besar, yaitu dengan ukuran diameter aggregasi kerang > 1 meter.  Pengukuran diameter aggregasi dilakukan 4 kali, masing-masing dengan aggregasi berbeda, sebagai ulangan. Sampel aggregasi kerang dilakukan dengan meletakkan kor (âcorâ) dengan diameter 10 cm di bagian tengah pada aggregasi kerang kecil, posisi pinggir dan tengah aggregasi besar. Sampel diambil juga sebanyak 4 kali (ulangan) pada masing aggregasi yang berbeda, sebagai ulangan. Kerang disortir dengan bantuan mikroskop, di mana kerang dengan ukuran 0.05). Faktor yang mempengaruhi penempelan dan rekruit dari agrregasi dengan ukuran berbeda didiskusikan.Kata kunci: Kerang Kotak; Septifer; recruit; aggregate; larva; Tiwoh
Magneto-transport study of intra- and intergrain transitions in the magnetic superconductors RuSr2GdCu2O8 and RuSr2(Gd1.5Ce0.5)Cu2O10
A characterization of the magnetic superconductors RuSr2GdCu2O8 [Ru-(1212)]
and RuSr2(Gd1.5Ce0.5)Cu2O10 [Ru-(1222)] through resistance measurements as a
function of temperature and magnetic field is presented. Two peaks in the
derivative of the resistive curves are identified as intra- and intergrain
superconducting transitions. Strong intragrain granularity effects are
observed, and explained by considering the antiphase boundaries between
structural domains of coherently rotated RuO6 octahedra as intragrain
Josephson-junctions. A different field dependence of the intragrain transition
temperature in these compounds was found. For Ru-(1212) it remains unchanged up
to 0.1 T, decreasing for higher fields. In Ru-(1222) it smoothly diminishes
with the increase in field even for a value as low as 100 Oe. These results are
interpreted as a consequence of a spin-flop transition of the Ru moments. The
large separation between the RuO2 layers in Ru-(1222) promotes a weak
interlayer coupling, leading the magnetic transition to occur at lower fields.
The suppression rate of the intragrain transition temperature is about five
times higher for Ru-(1222), a result we relate to an enhancement of the 2D
character of the vortex structure. A distinctive difference with conventional
cuprates is the sharp increase in amplitude of the intergrain peak in both
systems, as the field is raised, which is ascribed to percolation through a
fraction of high quality intergrain junctions.Comment: Submitted for Physical Review
- âŠ