722 research outputs found
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Density-Dependent Survival in the Larval Stage of an Invasive Insect: Dispersal vs. Predation
1. The success of invasive species is often thought to be due to release from natural enemies. This hypothesis relies on the assumption that species are regulated by top-down forces in their native range and implies that species are likely to be regulated by bottom-up forces in the invasive range. Neither of these assumptions has been consistently supported with insects, a group which include many highly destructive invasive pest species.
2. Winter moth (Operophtera brumata) is an invasive defoliator in North America that appears to be regulated by mortality in the larval stage in its invasive range. To assess whether regulation in the invasive range is caused by top-down or bottom-up forces, we sought to identify the main causes of larval mortality.
3. To measure the importance of different sources of winter moth larval mortality, we used observational and manipulative field studies to measure dispersal, predation, parasitism, disease. We measured the response of larval dispersal in the field to multiple aspects of foliar quality, including total phenolics, pH 10 oxidized phenolics, trichome density, total nitrogen, total carbon, and carbon-nitrogen ration. We also used manipulative laboratory studies to measure the presence of cannibalism and dispersal.
4. Tree-level declines in density were driven by density-dependent larval dispersal of early instars with very little mortality caused by other factors. Later instar larvae dispersed at increased rates from previously damaged vs. undamaged foliage, and field larval dispersal rates were related to proportion of oxidative phenolics in 2015, suggesting that larval dispersal may have been mediated by an induced decline in foliar quality.
5. We conclude that winter moth population densities are regulated in New England by density-dependent larval dispersal possibly mediated by phenolic oxidative capacity. The suggested role of host plant quality in mediating dispersal means that winter moth population densities in New England appear to be regulated by bottom up forces, aligning with the assumptions of the natural enemy release hypothesis. This is the first study known to the authors presenting data showing a negative effect on insect herbivore performance from pH 10 oxidized phenolics
Linguistic prosody and comprehension of idioms and proverbs in subjects of school age
A crucial component of language is represented by the prosodic system because it provides essential elements to speaker about how a sentence should be interpreted or intended (Fodor, 2002). Increasing interest from researchers also relates to the understanding of figurative language (Levorato, & Cacciari, 2002). In the figures of speech that the speaker wants the listener intends something more or different than what is explicitly stated (Glucksberg, 2001)..
In particular, prosodic intonation is crucial in the resolution of syntactic ambiguity and structural features that constitute the complex messages, such as idioms and proverbs.
A crucial component of language, therefore, is represented by the prosodic system because it provides essential elements to talking about how a sentence should be interpreted or understood . The ability to relate to metalinguistic understanding the cognitive processes that allow you to reflect on language and manipulate its characteristics. These capabilities are essential to recognize and resolve the ambiguities of a complex message, you can control and plan the way we produce and understand language (Levorato, 2007).
The study demonstrates that an understanding prosodic correlates with the understanding of idioms and proverbs, which are crucial for the achievement of metalinguistic awareness, are influenced by the level of schooling and socio-cultural
Measuring emptiness: Validation of the Italian version of the Subjective Emptiness Scale in clinical and non-clinical populations
Background: Although a feeling of emptiness is listed only as a symptom of the DSM-5 borderline personality disorder, it is commonly encountered in other disorders. The aim of this study was to validate the Italian version of the Subjective Emptiness Scale (SES-I), a 7-item self-report instrument assessing the feeling of emptiness. Methods: Participants in one clinical group (n = 63) and one non-clinical group (n = 48) completed the SES-I along with several other instruments. A principal component analysis was used to analyze the structure of the SES-I and Cronbach's alpha and Rho's Spearman were used to establish aspects of reliability and validity, respectively. Results: The SES-I has a unidimensional structure reflecting the core feature of the feeling of emptiness. It showed an excellent internal consistency (a = 0.92) and convergent validity, as demonstrated by significant correlations with scores on the Beck Depression Inventory – II and conceptually related scales and subscales of the Millon Clinical Multiaxial Inventory – III and Personality Inventory for DSM-5. Divergent validity was also demonstrated for the SES-I. SES-I scores in the clinical group were significantly higher than in the non-clinical group. A significant relationship was not found between the feeling of emptiness and self-harming behavior, impulsivity and acting-out. Limitations: A small sample size, several significant differences between the clinical and non-clinical groups and diagnostic heterogeneity in the clinical group limit generalizability of the study. Conclusion: The SES-I is a valid and reliable instrument, which should improve assessment of the feeling of emptiness and help clinicians better understand this complex phenomenon
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Development of a land evaluation and site assessment (LESA) model for forestry in Lane County, Oregon
A Land Evaluation and Site Assessment (LESA) Model was
developed for the forested soils of Lane County, in western Oregon,
based on soil potential ratings and indexes of parcel size and
adjacent and surrounding land use conflict. Lane County's economy
is heavily dependent on resource production uses of land for
forestry. At the same time, population growth around metropolitan
areas creates pressure to convert rural land from large resource use
parcels to smaller rural residential parcels.
Planning for future allocation of land among competing uses
promoted the county to develop an objective method for determining
the relative quality of any parcel of land for forestry. Parcels of
lower quality could then be considered for conversion to rural
residential uses.
LESA was developed by the SCS for use by state and local
governments as an objective method of evaluating the resource
production quality of land for planning purposes. Land evaluation
(LE) measures the relative suitability of the soils of a given
parcel for forestry. Site Assessment (SA) measures the relative
suitability of the setting in which the parcel occurs. The soil potential ratings (SPR's) were developed from soil map
unit characteristics defined in the Soil Survey of the Lane County
Area. SPR's are indexes of the net return to soil management for
forestry. Each soil is assigned an expected output, or yield, to soil
management for forestry using a computer model called DFSIM.
Management practices required to achieve that yield also are
specified. Monetary values are determined for both yields and
management practices, and the difference between price received and
total costs is a measure of soil potential. The soil having the
highest net return to soil management is assigned an arbitrary value
of 100 points. All other soils are rated by expressing their net
return as a percent of the maximum.
Management practices in each of four categories - site
preparation and stand establishment, thinning, harvest, and road
construction and maintenance - were prescribed, and their costs
determined, based on their interactions with soil slope, erodibility,
depth, bedrock hardness, and coarse fragment content.
Land evaluation was completed by overlaying a soil map of the
land parcel of interest, determining the fractional amount of each
soil present, and multiplying that amount by the corresponding soil
potential rating. The sum of all the products is a weighted average
soil potential rating for a parcel.
Development of the Site Assessment (SA) portion of the model was
guided by a technical committee of forest management professionals and
land use specialists. The committee chose the factors that were
considered important in site assessment and how much weight to give to each factor. For this LESA model, two factors were identified:
compatibility with other land uses, and parcel size.
The concept of compatibility implies that large scale forestry
uses are compatible with each other but are not compatible with small
scale residential uses. Generally, the more non-resource related
dwellings in forestry areas, the greater the potential conflict due to
noise, chemical spraying, dust, smoke, and vandalism.
Two empirical formulas were developed to measure compatibility
effects. One accounts for the number and density of non-compatible
parcels adjacent to the parcel of interest. The other measures the
density of non-compatible parcels within a specified distance of the
target parcel, which was 1/2 mile.
Parcel size implies that large parcels are more suitable for
resource uses than small ones, and that parcels surrounded by a few
large parcels are more favorable than parcels surrounded by many small
parcels. An empirical formula was derived to measure these effects.
Optimum parcel sizes depended on slope, parcel shape, and the number
of streams running through the parcel.
The final step in the LESA model development was to specify a
total point value, and to decide on the proportion of that total that
would go to each of the factors, soils, compatibility, and parcel
size. In previous LESA models the point total has been 300. This
total was allocated to each of the factors as follows: soils 105,
adjacent use 75, surrounding use 45, and parcel size 75.
Validation is a critical part of the development of a LESA model,
and it is done by applying the LESA criteria to several parcels that represent a range of soil resource quality, sizes, and land use
settings. Each parcel must then be examined in the field by the LESA
development committee. Field examination is essential in order to
make needed adjustments in empirical formulas. Through the repeating
of this validation process, the model is fine tuned and its accuracy
for planning purposes is validated.
LESA scores can be used to distinguish between primary and
secondary land resources. Primary resource lands are sufficiently
valuable for forest uses that land use controls are justified to
prevent the introduction of non-resource development. Secondary
resource land is of lesser quality and is a more appropriate site for
smaller scale resource uses and certain non-resource uses.
Information from the test parcels was used to set primary/secondary
thresholds for each factor and to develop empirical criteria for
classifying each parcel
Metallurgical and statistical approaches to the study of cast iron street furniture
The evolution of microstructure in relation to dating and nationality of origin was investigated in twenty-four cast iron objects of street furniture produced between XIX and XX centuries in United Kingdom, France, and Italy. Chemical composition of the metalworks was evaluated by glow-discharge optical emission spectrometry. Fragments from the cast irons were analyzed by optical microscopy and scanning electron microscopy with energy-dispersive spectroscopy. Form, distribution, and size of graphite were evaluated in the microstructure according to standard EN ISO 945-1:2008. An image analysis software was employed to quantify the area fraction of graphite in the matrix, major axis, and shape factor of graphite lamellae, area fraction of manganese sulfides (ψS), area fraction of steadite, and number of eutectic cells per area unit. All data were grouped and linear discrimination analysis (LDA) was applied to assess the group assignment and the probability of correct classification for each metalwork. The results showed that the microstructural features were compatible with those of cast irons produced in the XIX and XX centuries. Values of ψS also suggested re-melting of cast irons, associated with recycling of cast iron and/or steel scraps. The high values of steadite found in the metalworks are probably due to the excellent castability required for complex shape castings in these centuries. The LDA multivariate analysis allowed to discriminate cast irons based on the year of manufacturing and the nationality of origin
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