206 research outputs found
Estimating Temporal Trend in the Presence of Spatial Complexity: A Bayesian Hierarchical Model for a Wetland Plant Population Undergoing Restoration
Monitoring programs that evaluate restoration and inform adaptive management are important for addressing environmental degradation. These efforts may be well served by spatially explicit hierarchical approaches to modeling because of unavoidable spatial structure inherited from past land use patterns and other factors. We developed Bayesian hierarchical models to estimate trends from annual density counts observed in a spatially structured wetland forb (Camassia quamash [camas]) population following the cessation of grazing and mowing on the study area, and in a separate reference population of camas. The restoration site was bisected by roads and drainage ditches, resulting in distinct subpopulations (“zones”) with different land use histories. We modeled this spatial structure by fitting zone-specific intercepts and slopes. We allowed spatial covariance parameters in the model to vary by zone, as in stratified kriging, accommodating anisotropy and improving computation and biological interpretation. Trend estimates provided evidence of a positive effect of passive restoration, and the strength of evidence was influenced by the amount of spatial structure in the model. Allowing trends to vary among zones and accounting for topographic heterogeneity increased precision of trend estimates. Accounting for spatial autocorrelation shifted parameter coefficients in ways that varied among zones depending on strength of statistical shrinkage, autocorrelation and topographic heterogeneity—a phenomenon not widely described. Spatially explicit estimates of trend from hierarchical models will generally be more useful to land managers than pooled regional estimates and provide more realistic assessments of uncertainty. The ability to grapple with historical contingency is an appealing benefit of this approach
Key Success Factors and Barriers for Small Businesses: Comparative Analysis
AbstractThis paper analyses the current situation of small businesses, their outlook and their problems in Europe and in Russia. The number of small businesses opened, legislative system, number of self-employed without employees, influence of bureaucratic system on small business's life, unemployment and corruption are considered in this study. The object of this paper is understanding what can modify the life of small companies. Thus the analysis of every factor is useful to understand how the economy could change, what is correct and what resolutions make the life of small businesses better. The analysis is made using data from Eurostat, Rosstat, and Fedstat (an OECD institutional website), studying how values of indicators have changed during recent years. The results clearly show that the development of small companies is correlated with the development of good institutions, a sane community and trust and optimism in economy and small business sector
Recommended from our members
Lidar-derived canopy architecture predicts brown creeper occupancy of two western coniferous forests
In western conifer-dominated forests where the abundance of old-growth stands is decreasing, species
such as the Brown Creeper (Certhia americana) may be useful as indicator species for monitoring the health
of old-growth systems because they are strongly associated with habitat characteristics associated with old growth
and are especially sensitive to forest management. Light detection and ranging (lidar) is useful for acquiring
fine-resolution, three-dimensional data on vegetation structure across broad areas. We evaluated Brown Creeper
occupancy of forested landscapes by using lidar-derived canopy metrics in two coniferous forests in Idaho. Density
of the upper canopy was the most important variable for predicting Brown Creeper occupancy, although mean
height and height variability were also included in the top models. The upper canopy was twice as dense and the
mean height was almost 50% higher at occupied than at unoccupied sites. Previous studies have found indicators of
canopy density to be important factors for Brown Creeper habitat; however, this represents the first time that lidar
data have been used to examine this relationship empirically through the mapping of the upper canopy density that
cannot be continuously quantified by field-based methods or passive remote sensing. Our model’s performance
was classified as “good” by multiple criteria. We were able to map probabilities of Brown Creeper occupancy in
~50 000 ha of forest, probabilities that can be used at the local, forest-stand, and landscape scales, and illustrate the
potential utility of lidar-derived data for studies of avian distributions in forested landscapes.En los bosques dominados por coníferas del oeste, donde está disminuyendo la abundancia de
rodales maduros, las especies como Certhia americana pueden ser útiles como especies indicadoras para monitorear
la salud de los sistemas maduros debido a que están fuertemente asociadas con las características del hábitat
vinculadas con el bosque maduro y son especialmente sensibles al manejo del bosque. El sistema de detección
y alcance de luz (denominado lidar, un acrónimo del inglés “light detection and ranging”) es útil para adquirir
datos tridimensionales de alta resolución de la estructura de la vegetación a través de grandes áreas. Evaluamos
la ocupación de C. americana de paisajes boscosos usando métricas del dosel derivadas de lidar en dos bosques
de coníferas en Idaho. La densidad del dosel alto fue la variable más importante para predecir la ocupación de
C. americana, aunque la altura media y la variabilidad de la altura también fueron incluidas en los mejores modelos.
El dosel alto fue dos veces más denso y la altura media fue casi 50% más alta en los sitios ocupados que en
los sitios desocupados. Estudios previos han encontrado que los indicadores de densidad del dosel son factores
importantes del hábitat de C. americana; sin embargo, esto representa la primera vez que datos de lidar han sido
usados para examinar esta relación de modo empírico a través del mapeo de la densidad del dosel alto, de un modo
continuo que no puede ser cuantificado por métodos basados en trabajo de campo o muestreo remoto pasivo. El
desempeño de nuestro modelo fue clasificado como “bueno” por múltiples criterios. Fuimos capaces de mapear las
probabilidades de ocupación de C. americana en ~50 000 ha de bosque, probabilidades que pueden ser usadas a
las escalas local, de rodal de bosque y de paisaje, y que ilustran la utilidad potencial de los datos derivados de lidar
para estudios de distribución de aves en paisajes boscosos.Keywords: Brown Creeper,
Certhia americana,
mapping,
habitat,
forest,
occupancy,
lida
Evaluation of the MODIS LAI product using independent lidar-derived LAI: A case study in mixed conifer forest
This study presents an alternative assessment of the MODIS LAI product for a 58,000 ha evergreen needleleaf forest located in the western Rocky Mountain range in northern Idaho by using lidar data to model (R2=0.86, RMSE=0.76) and map LAI at higher resolution across a large number of MODIS pixels in their entirety. Moderate resolution (30 m) lidar-based LAI estimates were aggregated to the resolution of the 1-km MODIS LAI product and compared to temporally-coincident MODIS retrievals. Differences in the MODIS and lidar-derived values of LAI were grouped and analyzed by several different factors, including MODIS retrieval algorithm, sun/sensor geometry, and sub-pixel heterogeneity in both vegetation and terrain characteristics. Of particular interest is the disparity in the results when MODIS LAI was analyzed according to algorithm retrieval class. We observed relatively good agreement between lidar-derived and MODIS LAI values for pixels retrieved with the main RT algorithm without saturation for LAI LAI≤4. Moreover, for the entire range of LAI values, considerable overestimation of LAI (relative to lidar-derived LAI) occurred when either the main RT with saturation or back-up algorithm retrievals were used to populate the composite product regardless of sub-pixel vegetation structural complexity or sun/sensor geometry. These results are significant because algorithm retrievals based on the main radiative transfer algorithm with or without saturation are characterized as suitable for validation and subsequent ecosystem modeling, yet the magnitude of difference appears to be specific to retrieval quality class and vegetation structural characteristics
Active Ground Optical Remote Sensing for Improved Monitoring of Seedling Stress in Nurseries
Active ground optical remote sensing (AGORS) devices mounted on overhead irrigation booms could help to improve seedling quality by autonomously monitoring seedling stress. In contrast to traditionally used passive optical sensors, AGORS devices operate independently of ambient light conditions and do not require spectral reference readings. Besides measuring red (590–670 nm) and near-infrared (>760 nm) reflectance AGORS devices have recently become available that also measure red-edge (730 nm) reflectance. We tested the hypothesis that the additional availability of red-edge reflectance information would improve AGORS of plant stress induced chlorophyll breakdown in Scots pine (Pinus sylvestris). Our results showed that the availability of red-edge reflectance information improved AGORS estimates of stress induced variation in chlorophyll concentration (r2 > 0.73, RMSE < 1.69) when compared to those without (r2 = 0.57, RMSE = 2.11)
Recommended from our members
How much does the time lag between wildlife field-data collection and LiDAR-data acquisition matter for studies of animal distributions? A case study using bird communities
Vegetation structure quantified by light detection and ranging (LiDAR) can improve understanding of wildlife occupancy and species-richness patterns. However, there is often a time lag between the collection of LiDAR data and wildlife data. We investigated whether a time lag between the LiDAR acquisition and field-data acquisition affected mapped wildlife distributions ranging from an individual species distribution to total avian species richness in a conifer forest. We collected bird and LiDAR data in 2009 across a 20,000 ha forest in northern Idaho. Using the 2009 LiDAR data, we modelled the probability of occurrence for the brown creeper (Certhia americana). Using the same 2009 LiDAR data, we additionally modelled total avian species richness and richness of three different bird nesting guilds (ground/understory, mid/upper canopy and cavity). We mapped brown creeper occupancy probability and species richness using the 2009 models, and then compared these maps with maps based on the same models applied to a 2003-LiDAR dataset. A prior study identified areas harvested between 2003 and 2009. There was on average a 5% absolute decrease in mapped probabilities of brown creeper occurrence in non-harvest areas between 2003 and 2009. Species richness changed by less than one species in all cases within non-harvest areas between the 2003 and 2009 maps. Although these comparisons were statistically significant at the p < 0.0001 level, it is likely that the high number of map cells (~480,000) influenced this result. Similar patterns between our 2003 and 2009 maps in non-harvest areas for this suite of avian responses suggests that a 6-year difference between field-data collection and LiDAR-data collection has a minimal effect on mapped avian patterns in an undisturbed coniferous forest. However, because this is one case study in one ecosystem, additional work examining the effect of temporal lags between LiDAR and field-data collection on mapping wildlife distributions is warranted in additional ecosystems
The Identity of Proteins Associated with a Small Heat Shock Protein during Heat Stress \u3ci\u3ein Vivo\u3c/i\u3e Indicates That These Chaperones Protect a Wide Range of Cellular Functions
The small heat shock proteins (sHSPs) are a ubiquitous
class of ATP-independent chaperones believed to
prevent irreversible protein aggregation and to facilitate
subsequent protein renaturation in cooperation
with ATP-dependent chaperones. Although sHSP chaperone
activity has been studied extensively in vitro, understanding
the mechanism of sHSP function requires
identification of proteins that are sHSP substrates in
vivo. We have used both immunoprecipitation and affinity
chromatography to recover 42 proteins that specifically
interact with Synechocystis Hsp16.6 in vivo during
heat treatment. These proteins can all be released from
Hsp16.6 by the ATP-dependent activity of DnaK and cochaperones
and are heat-labile. Thirteen of the putative
substrate proteins were identified by mass spectrometry
and reveal the potential for sHSPs to protect cellular
functions as diverse as transcription, translation, cell
signaling, and secondary metabolism. One of the putative
substrates, serine esterase, was purified and tested
directly for interaction with purified Hsp16.6. Hsp16.6
effectively formed soluble complexes with serine esterase
in a heat-dependent fashion, thereby preventing formation
of insoluble serine esterase aggregates. These
data offer critical insights into the characteristics of
native sHSP substrates and extend and provide in vivo
support for the chaperone model of sHSP function
The Identity of Proteins Associated with a Small Heat Shock Protein during Heat Stress \u3ci\u3ein Vivo\u3c/i\u3e Indicates That These Chaperones Protect a Wide Range of Cellular Functions
The small heat shock proteins (sHSPs) are a ubiquitous
class of ATP-independent chaperones believed to
prevent irreversible protein aggregation and to facilitate
subsequent protein renaturation in cooperation
with ATP-dependent chaperones. Although sHSP chaperone
activity has been studied extensively in vitro, understanding
the mechanism of sHSP function requires
identification of proteins that are sHSP substrates in
vivo. We have used both immunoprecipitation and affinity
chromatography to recover 42 proteins that specifically
interact with Synechocystis Hsp16.6 in vivo during
heat treatment. These proteins can all be released from
Hsp16.6 by the ATP-dependent activity of DnaK and cochaperones
and are heat-labile. Thirteen of the putative
substrate proteins were identified by mass spectrometry
and reveal the potential for sHSPs to protect cellular
functions as diverse as transcription, translation, cell
signaling, and secondary metabolism. One of the putative
substrates, serine esterase, was purified and tested
directly for interaction with purified Hsp16.6. Hsp16.6
effectively formed soluble complexes with serine esterase
in a heat-dependent fashion, thereby preventing formation
of insoluble serine esterase aggregates. These
data offer critical insights into the characteristics of
native sHSP substrates and extend and provide in vivo
support for the chaperone model of sHSP function
- …