The reliability of airborne light detection and ranging (LiDAR) for delineating individual trees and estimating aboveground biomass (AGB) has been proven in a diverse range of ecosystems, but can be ...difficult and costly to commission. Point clouds derived from structure from motion (SfM) matching techniques obtained from unmanned aerial systems (UAS) could be a feasible low-cost alternative to airborne LiDAR scanning for canopy parameter retrieval. This study assesses the extent to which SfM three-dimensional (3D) point clouds-obtained from a light-weight mini-UAS quadcopter with an inexpensive consumer action GoPro camera-can efficiently and effectively detect individual trees, measure tree heights, and provide AGB estimates in Australian tropical savannas. Two well-established canopy maxima and watershed segmentation tree detection algorithms were tested on canopy height models (CHM) derived from SfM imagery. The influence of CHM spatial resolution on tree detection accuracy was analysed, and the results were validated against existing high-resolution airborne LiDAR data. We found that the canopy maxima and watershed segmentation routines produced similar tree detection rates (~70%) for dominant and co-dominant trees, but yielded low detection rates (<35%) for suppressed and small trees due to poor representativeness in point clouds and overstory occlusion. Although airborne LiDAR provides higher tree detection rates and more accurate estimates of tree heights, we found SfM image matching to be an adequate low-cost alternative for the detection of dominant and co-dominant tree stands.
A chill sequence at the base of the Lower Zone of the western Bushveld Complex at Union Section, South Africa, contains aphanitic Mg-rich basaltic andesite and spinifex-textured komatiite. The ...basaltic andesite has an average composition of 15.2 % MgO, 52.8 % SiO
2
, 1205 ppm Cr, and 361 ppm Ni, whereas the komatiite has 18.7 % MgO, 1515 ppm Cr, and 410 ppm Ni. Both rock types have very low concentrations of immobile incompatible elements (0.14–0.72 ppm Nb, 7–31 ppm Zr, 0.34–0.69 ppm Th, 0.23–0.27 wt% TiO
2
), but high PGE contents (19–23 ppb Pt, 15–16 ppb Pd) and Pt/Pd ratios (Pt/Pd 1.4). Strontium and S isotopes show enriched signatures relative to most other Lower Zone rocks. The rocks could represent a ~20 % partial melt of subcontinental lithospheric mantle. This would match the PGE content of the rocks. However, this model is inconsistent with the high SiO
2
, Fe, and Na
2
O contents and, in particular, the low K
2
O, Zr, Hf, Nb, Ta, Th, LREE, Rb, and Ba contents of the rocks. Alternatively, the chills could represent a komatiitic magma derived from the asthenosphere that underwent assimilation of the quartzitic floor accompanied by crystallization of olivine and chromite. This model is consistent with the lithophile elements and the elevated Sr and S isotopic signatures of the rocks. However, in order to account for the high Pt and Pd contents of the magma, the mantle must have been twice as rich in PGE as the current estimate for PUM, possibly due to a component of incompletely equilibrated late veneer.
Emotional Labor, Strain, and Performance Hülsheger, Ute R; Lang, Jonas W. B; Maier, Günter W
Journal of occupational health psychology,
10/2010, Letnik:
15, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Models of emotional labor suggest that emotional labor leads to strain and affects job performance. Although the link between emotional labor, strain, and performance has been well documented in ...cross-sectional field studies, not much is known about the causal direction of relationships between emotional labor, strain, and performance. Goal of the present study was therefore to test the direction of effects in a two-wave longitudinal panel study using a sample of 151 trainee teachers. Longitudinal lagged effects were tested using structural equation modeling. Results revealed that the emotional labor strategy of surface acting led to increases in subsequent strain while deep acting led to increases in job performance. In contrast, there was no indication of reverse causation: Neither strain nor job performance had a significant lagged effect on subsequent surface or deep acting. Overall, results support models of emotional labor suggesting that surface and deep acting causally precede individual and organizational well-being.
Although the topic of value congruence has attracted considerable attention from researchers and practitioners, evidence for the link between person-supervisor value congruence and followers' ...reactions is less robust than often assumed. This study addresses three central issues in our understanding of person-supervisor value congruence (a) by assessing the impact of objective person-supervisor value congruence rather than subjective value congruence, (b) by examining the differential effects of value congruence in strongly versus moderately held values, and (c) by exploring perceived empowerment as a central mediating mechanism. Results of a multi-source study comprising 116 person-supervisor dyads reveal that objective value congruence relates to followers' job satisfaction and affective commitment and that this link can be explained by followers' perceived empowerment. Moreover, polynomial regression and response surface analyses reveal that congruence effects vary with the importance that leaders and followers ascribe to a certain value: Congruency in strongly held values have more robust relations with followers' outcomes than congruence in moderately held values.
Young people with self-experienced cognitive thought and perception deficits (basic symptoms) may present with an early initial prodromal state (EIPS) of psychosis in which most of the disability and ...neurobiological deficits of schizophrenia have not yet occurred.
To investigate the effects of an integrated psychological intervention (IPI), combining individual cognitive-behavioural therapy, group skills training, cognitive remediation and multifamily psychoeducation, on the prevention of psychosis in the EIPS.
A randomised controlled, multicentre, parallel group trial of 12 months of IPI v. supportive counselling (trial registration number: NCT00204087). Primary outcome was progression to psychosis at 12- and 24-month follow-up.
A total of 128 help-seeking out-patients in an EIPS were randomised. Integrated psychological intervention was superior to supportive counselling in preventing progression to psychosis at 12-month follow-up (3.2% v. 16.9%; P = 0.008) and at 24-month follow-up (6.3% v. 20.0%; P = 0.019).
Integrated psychological intervention appears effective in delaying the onset of psychosis over a 24-month time period in people in an EIPS.
The Labrador Trough in northern Quebec is currently the focus of ongoing exploration for magmatic Ni-Cu-platinum group element (PGE) sulphide ores. This geological belt hosts voluminous basaltic ...sills and lavas of the Montagnais Sill Complex, which are locally emplaced among sulphidic metasedimentary country rocks. The recently discovered Idefix PGE-Cu prospect represents a stack of gabbroic sills that host stratiform patchy disseminated to net-textured sulphides (0.2-0.4 g/t PGE+Au) over a thickness of ∼20 m, for up to 7 km. In addition, globular sulphides occur at the base of the sill, adjacent to the metasedimentary floor rocks. Whole-rock and PGE geochemistry indicates that the sills share a common source and that the extracted magma underwent significant fractionation before emplacement in the upper crust. To develop the PGE-enriched ores, sulphide melt saturation was attained before final emplacement, peaking at R factors of ∼10 000. Globular sulphides entrained along the base of the sill ingested crustally derived arsenic and were ultimately preserved in the advancing chilled margin.
The influence of the preparation method on structural properties and on the catalytic activity of sol–gel derived binary copper manganese oxides for CO oxidation in dry air at room temperature has ...been investigated. The catalysts were characterised by means of BET and X-ray diffraction. All results were compared with a commercial Hopcalite sample. Subsequent conventional optimisation of the most active sample – prepared by the so-called ethylene–glycol method (EG I) – including compositional and calcination temperature variation revealed Cu
20Mn
80O
x
(EG I) calcined at 400
°C as very active catalyst. Sintering processes induced by the crystallisation of the amorphous material above 400
°C cause a dramatic decrease of the catalysts’ surface area accompanied by deactivation. XPS data recordings were used to investigate the oxidation states of the metals in this catalyst and in the reference material. In conclusion a combination of high surface area, amorphous state and the presence of Cu
2+ and Mn
3+ was found to be essential for the high catalytic activity of the binary copper manganese oxides. The reactivity of the best catalyst was tested under application-relevant conditions, i.e. in moist air and at low-temperature fuel cell conditions.
Research on the relationship of implicit motives and effective leadership emphasises the importance of a socialised need for power, whereas high levels of the need for affiliation are assumed to ...thwart a leader’s success. In our study, we experimentally analysed the impact of leaders’ socialised need for power and their need for affiliation on perceptions of transformational leadership and various success indicators. Using paper-people vignettes, we contrasted leaders characterised by either motive with those concerned with personalised power or achievement. Results based on
N
= 80 employees show that leaders high in socialised power were rated more successful and elicited more identification and organisational citizenship behaviour (OCB) in followers, and that in most cases this effect was mediated by perceptions of transformational leadership. For all outcomes but OCB, findings remained unchanged when affiliation-motivated leaders were considered. Exploratory analyses contrasting socialised power-motivated and affiliation-motivated leaders show that with regard to attitudinal outcomes affiliation-motivated leaders were, on average, as effective as socialised power-motivated ones.
ABSTRACT
The Palaeoproterozoic Penikat layered ultramafic–mafic intrusion in northern Finland is one of the most richly mineralized layered intrusions on Earth, containing at least six platinum-group ...element (PGE) enriched horizons exposed along >20 km of strike, amongst them the SJ reef, which at ∼3–7 ppm Pt + Pd over a width of ∼1–2 m is surpassed by few other PGE reefs globally in terms of its endowment in PGE. Important PGE enrichments also occur in the PV reef (average 2·6 ppm Pd, 4 ppm Pt over 1·1 m) and AP1 reef (average 6·2 ppm Pd, 1·7 ppm Pt over 0·7 m). Here we present new major and high-precision trace element and Nd isotope data from a traverse across the intrusion, and a new U–Pb age of 2444 ± 8 Ma for the intrusion. We show that the PGE reefs formed by predominantly orthomagmatic processes as, for example, reflected by well-defined positive correlations between Pt + Pd and Os + Ir + Ru contents. Late-magmatic fluids played no significant role in concentrating PGE. There are at least six cyclic units in the intrusion, displaying a progressive upward decrease in differentiation indices Mg# and Cr/V. Subdued stratigraphic variations in incompatible trace element ratios (Ce/Sm mostly 5–10) and Nd isotope compositions (εNd –3 to –1) indicate that mixing of magmas of distinct lineage, or in situ contamination with country rocks, was not required to form the PGE reefs. There is also no evidence for addition of external sulphur to the magma, based on S/Se ratios at, or below, primitive mantle levels. Instead, we propose that sulphide melt saturation at Penikat was reached in response to fractionation of a siliceous, high-magnesium basalt, and that the sulphides were concentrated through hydrodynamic phase sorting, consistent with bonanza-style PGE grades in large potholes.
Asthma management guidelines provide recommendations for the optimum control of asthma. This survey assessed the current levels of asthma control as reported by patients, which partly reflect the ...extent to which guideline recommendations are implemented. Current asthma patients were identified by telephone by screening 73,880 households in seven European countries. Designated respondents were interviewed on healthcare utilization, symptom severity, activity limitations and asthma control. Current asthma patients were identified in 3,488 households, and 2,803 patients (80.4%) completed the survey. Forty-six per cent of patients reported daytime symptoms and 30% reported asthma-related sleep disturbances, at least once a week. In the past 12 months, 25% of patients reported an unscheduled urgent care visit, 10% reported one or more emergency room visits and 7% reported overnight hospitalization due to asthma. In the past 4 weeks, more patients had used prescription quick-relief medication (63%) than inhaled corticosteroids (23%). Patient perception of asthma control did not match their symptom severity; approximately 50% of patients reporting severe persistent symptoms also considered their asthma to be completely or well controlled. The current level of asthma control in Europe falls far short of the goals for long-term asthma management. Patients' perception of asthma control is different from their actual asthma control.
PDF
