bluuebunny/crossref_metadata_2025 huggingface dataset:
The Corporate Propensity to Save
Authors: RIDDICK LEIGH A. , WHITED TONI M.
Published: July 2009

Why do corporations accumulate liquid assets? We show theoretically that intertemporal trade‐offs between interest income taxation and the cost of external finance determine optimal savings. Intriguingly, we find that, controlling for Tobin's q, saving and cash flow are negatively related because firms lower cash reserves to invest after receiving positive cash‐flow shocks, and vice versa. Consistent with theory, we estimate negative propensities to save out of cash flow. We also find that income uncertainty affects saving more than do external finance constraints. Therefore, contrary to previous evidence, saving propensities reflect too many forces to be used to measure external finance constraints.
Target Behavior and Financing: How Conclusive Is the Evidence?
Authors: CHANG XIN , DASGUPTA SUDIPTO
Published: July 2009

The notion that firms have a debt ratio target that is a primary determinant of financing behavior is influential in finance. Yet, how definitive is the evidence? We address this issue by generating samples where financing is unrelated to a firm's current debt ratio or a target. We find that much of the available evidence in favor of target behavior based on leverage ratio changes can be reproduced for these samples. Taken together, our findings suggest that a number of existing tests of target behavior have no power to reject alternatives.
Financially Constrained Stock Returns
Authors: LIVDAN DMITRY , SAPRIZA HORACIO , ZHANG LU
Published: July 2009

We study the effect of financial constraints on risk and expected returns by extending the investment‐based asset pricing framework to incorporate retained earnings, debt, costly equity, and collateral constraints on debt capacity. Quantitative results show that more financially constrained firms are riskier and earn higher expected stock returns than less financially constrained firms. Intuitively, by preventing firms from financing all desired investments, collateral constraints restrict the flexibility of firms in smoothing dividend streams in the face of aggregate shocks. The inflexibility mechanism also gives rise to a convex relation between market leverage and expected stock returns.
First‐Order Risk Aversion, Heterogeneity, and Asset Market Outcomes
Authors: CHAPMAN DAVID A. , POLKOVNICHENKO VALERY
Published: July 2009

We examine a wide range of two‐date economies populated by heterogeneous agents with the most common forms of nonexpected utility preferences used in finance and macroeconomics. We demonstrate that the risk premium and the risk‐free rate in these models are sensitive to ignoring heterogeneity. This follows because of endogenous withdrawal by nonexpected utility agents from the market for the risky asset. This finding is important precisely because these alternative preferences have frequently been proposed as possible resolutions to various asset pricing puzzles, and they have all been examined exclusively in a representative agent framework.
Who Gambles in the Stock Market?
Authors: KUMAR ALOK
Published: July 2009

This study shows that the propensity to gamble and investment decisions are correlated. At the aggregate level, individual investors prefer stocks with lottery features, and like lottery demand, the demand for lottery‐type stocks increases during economic downturns. In the cross‐section, socioeconomic factors that induce greater expenditure in lotteries are associated with greater investment in lottery‐type stocks. Further, lottery investment levels are higher in regions with favorable lottery environments. Because lottery‐type stocks underperform, gambling‐related underperformance is greater among low‐income investors who excessively overweight lottery‐type stocks. These results indicate that state lotteries and lottery‐type stocks attract very similar socioeconomic clienteles.
A Viewpoint on the Impact of Device Advisories on Patient‐Centered Outcomes
Authors: PEDERSEN SUSANNE S. , VAN DEN BERG MARTHA , THEUNS DOMINIC A. M. J.
Published: July 2009

Device advisories due to potential hardware failure comprise one of the downsides of implantable cardioverter defibrillator (ICD) therapy. The impact of advisories on patient‐centered outcomes has largely been overlooked. We examined the impact of ICD advisories on patient‐centered outcomes via a systematic literature review. PubMed was searched in the period from 1980 to present using a combination of at set of a priori search terms. The reference lists of the included papers were searched by hand. A total of six studies were identified. All advisories were Class I, Class II, or a combination. The sample size across studies varied between 30 and 86 patients subject to an advisory; four of six studies used a case‐control design and two of six a prospective study design. There was considerable variability between notification of the advisory and assessment of the patient‐centered outcomes, ranging from 1 to 24 months. A mixture of generic and disease‐specific patient‐centered outcome measures was used. The evidence for an impact on device advisories was mixed, with the two prospective studies showing an increase in anxiety over time, whereas none of the larger case‐control studies found a difference in patient‐centered outcomes between cases and controls. Evidence for an impact of device advisories on patient‐centered outcomes is mixed. In order to incorporate a patient‐centered approach in clinical care, patient‐centered outcomes should form part of standard clinical practice and if available the assessments entered into ICD registries. Such registries would provide important insights into the impact of ICD advisories on patients’ well being.
The Psychological Impact of Implantable Cardioverter‐Defibrillator Recalls and the Durable Positive Effects of Counseling
Authors: FISHER JOHN D. , KOULOGIANNIS KONSTANTINOS P. , LEWALLEN LINDA , KATZ DANIEL , KIM SOO G. , FERRICK KEVIN J. , GROSS JAY N. , KRUMERMAN ANDREW K. , JOHNSTON DEBRA R. , MERCALDI BRIDGET C.
Published: July 2009

Background: It is known that patients with lifesaving devices such as implantable cardioverter‐defibrillators (ICDs) may be alarmed and worried by recalls or alerts related to their ICDs.

Objectives: This study aimed to determine whether counseling has any short‐ or long‐term benefits, and to look for characteristics that identify those most worried and those most in need of counseling.

Methods: Among 100 patients with recall or alert ICDs, 14 were pacer dependent; 50 had ICDs for 1° prevention and 22 were women. Patients completed a survey indicating how worried they were on learning of the recall or alert (0–10 scale). After counseling and advice in accordance with manufacturer guidelines, patients were asked to indicate their level of worry, and were again asked after 6 months.

Results: For all patients, the “worry level” at the initial interview was 5.0±3.7, falling to 2.2±3.0 after counseling (P < 0.001) and 1.4±2.3 after 6 months (P < 0.001 vs both earlier levels). There were no significant differences between those implanted for 1° versus 2° prevention or for pacer dependency. Women were initially more worried than men, but not for the long term. The 49 patients whose ICDs could be managed by reprogramming or software fix had significant reduction in worry after counseling and at 6 months compared to others. The 18 patients recommended for operative intervention remained more concerned after counseling (3.5±3.3 vs 1.9±2.9, P = 0.043).

Conclusions: Patients’ concerns resulting from ICD recalls or alerts can be reduced by appropriate counseling. Those patients whose ICDs could be reprogrammed to safer parameters had the most reduction in worry levels.
Right Ventricular Myocardial Function in Patients with Either Idiopathic or Ischemic Dilated Cardiomyopathy Without Clinical Sign of Right Heart Failure: Effects of Cardiac Resynchronization Therapy
Authors: D’ANDREA ANTONELLO , SALERNO GEMMA , SCARAFILE RAFFAELLA , RIEGLER LUCIA , GRAVINO RITA , CASTALDO FRANCESCA , COCCHIA ROSANGELA , LIMONGELLI GIUSEPPE , ROMANO MASSIMO , CALABRÒ PAOLO , NIGRO GERARDO , CUOMO SERGIO , BOSSONE EDUARDO , CASO PIO , CALABRÒ RAFFAELE
Published: July 2009

Objective: In dilated cardiomyopathy (DCM), right ventricular (RV) dysfunction has been reported and attributed both to altered loading conditions and to RV involvement in the myopathic process. The aim of the study was to detect RV myocardial function in DCM using two‐dimensional (2D) strain echocardiography and to assess the effects of cardiac resynchronization therapy (CRT) on RV myocardial strain during a 6‐month follow‐up.

Methods and Results: A total of 110 patients (mean age: 55.4 ± 11.2 years) with either idiopathic (n = 60) or ischemic (n = 50) DCM, without overt clinical signs of RV failure, underwent standard echo and 2D strain analysis of RV longitudinal strain in RV septal and lateral walls. The two groups were comparable for clinical variables (New York Heart Association class III in 81.8%). Left ventricular volumes, ejection fraction, stroke volume, and mitral valve effective regurgitant orifice were similar between the two groups. No significant differences were evidenced in Doppler mitral and tricuspid inflow measurements. RV diameters were mildly increased in patients with idiopathic DCM, while RV tricuspid annulus systolic excursion and Tei‐index were comparable between the two groups. RV global longitudinal strain and regional peak myocardial strain were significantly impaired in patients with idiopathic DCM compared with those having ischemic DCM (all P < 0.001). Using left ventricular end‐systolic volume as marker for response to CRT, 70 patients (63.3%) were long‐term responders. Ischemic DCM patient responders to CRT showed a significant improvement in RV peak systolic strain. Conversely, in patients with idiopathic DCM and in ischemic patients nonresponders to CRT, no improvement in RV function was evidenced. By multivariable analysis, in the overall population, ischemic etiology of DCM (P < 0.0001), positive response to CRT (P < 0.001), and longitudinal intraventricular dyssynchrony (P <0.01) emerged as the only independent determinants of RV global longitudinal strain after CRT.

Conclusions: Two‐dimensional strain represents a promising noninvasive technique to assess RV myocardial function in patients with DCM. RV myocardial deformation at baseline and after CRT are more impaired in idiopathic compared with ischemic DCM patients. Future longitudinal studies are warranted to understand the natural history of RV myocardial function, the extent of reversibility of RV dysfunction with CRT, and the possible prognostic impact of such indexes in patients with congestive heart failure.
Intracardiac Echocardiography‐Guided Cardiac Resynchronization Therapy: Technique and Clinical Application
Authors: SAKSENA SANJEEV , SIMON ANN MARIE , MATHEW PHILIP , NAGARAKANTI RANGADHAM
Published: July 2009

Background: We undertook a pilot investigation to evaluate the feasibility of a novel technique using intracardiac echocardiography (ICE) for intraoperative assessment of cardiac resynchronization therapy (CRT).

Methods: We evaluated ICE intraoperative imaging of left ventricular (LV) function and aortic valvular flow as well as safety of implementation. ICE was used to guide CRT system lead placement, assess impact of pacing modes, and optimization of device programming.

Results: Twenty‐three patients underwent ICE imaging. ICE showed global hypokinesis in six patients, regional wall motion abnormality only in 10 patients, and both in seven patients. Optimized CRT modes included mean atrioventricular (AV) interval of 170 ms and interventricular timing using simultaneous right ventricular (RV)‐LV pacing (five patients), LV pacing only (one patient), and sequential LV to RV stimulation (15 patients) or RV to LV stimulation (two patients). ICE‐guided CRT acutely improved mean left ventricular ejection fraction (LVEF) from 24 ± 9% to 41 ± 1% (P < 0.00001). During follow‐up of 3–24 (mean 11) months, New York Heart Association class improved in all patients from a mean of 3.2 ± 0.4 at implant to 1.6 ± 0.7 (P < 0.0001), with improvement of LVEF from 19 ± 7% to 34 ± 12% (P = 0.0001). Actuarial survival was 83% at 12 months.

Conclusions:

(1) ICE imaging is reliable and safe for continuous intraoperative imaging of LV wall motion, and assesses baseline status and impact of CRT interventions.
(2) Intraoperative ICE‐guided CRT optimization resulted in an increase in LVEF acutely and consistent improvement in heart failure.
(3) Sequential biventricular pacing and longer AV interval programming were more often used in ICE‐guided CRT.
Transvenous Removal of an Entangled Central Venous Line Following Complex Cardiac Surgery
Authors: SUN KE , AEBERT HERMANN , STOCK ULRICH A. , LISY MILAN , ZIEMER GERHARD , DOERNBERGER VOLKER
Published: July 2009

Unintended internal suturing of central venous lines or pulmonary artery catheters in the superior caval vein or the right atrium following cardiac surgery remains a rare but troublesome complication. The line is normally entangled in safety or hemostasis sutures after the removal of the superior caval cannulation. If mild tension is unsuccessful, the patient normally undergoes resternotomy. The objective of this brief communication is to describe of a simple and safe removal method using a transvenous rotational cutting device to divide the hemostasis suture. In order to avoid complicating bleeding, a time delay between initial placement and removal is highly recommended. For extraction, a fully equipped cardiovascular operating room with central venous and arterial lines, attached defibrillator pads, transesophageal echo monitoring, fluoroscopy, and a surgical team, including a heart and lung machine and a perfusionist standby, is mandatory.
Direct His Bundle Pacing Post AVN Ablation
Authors: LAKSHMANADOSS UMASHANKAR , AGGARWAL ASHIM , HUANG DAVID T. , DAUBERT JAMES P. , SHAH ABRAR
Published: July 2009

Atrioventricular nodal (AVN) ablation with concomitant pacemaker implantation is one of the strategies that reduce symptoms in patients with atrial fibrillation (AF). However, the long‐term adverse effects of right ventricular (RV) apical pacing have led to the search for alternating sites of pacing. Biventricular pacing produces a significant improvement in functional capacity over RV pacing in patients undergoing AVN ablation. Another alternative site for pacing is direct His bundle to reduce the adverse outcome of RV pacing. Here, we present a case of direct His bundle pacing using steerable lead delivery system in a patient with symptomatic paroxysmal AF with concurrent AVN ablation.
Abolition of Diaphragmatic Pacing by Nonsurgical Retraction of a Left Ventricular Lead
Authors: HERWEG BENGT , BAROLD S. SERGE
Published: July 2009

This report describes the nonsurgical elimination of intractable diaphragmatic stimulation by partial withdrawal of a left ventricular (LV) pacing lead (in the coronary venous system) with resultant preservation of LV pacing. The procedure entailed the use of a deflectable catheter in the right atrium for ensnaring the LV lead. At the 3‐month follow‐up, the absence of diaphragmatic stimulation was associated with a satisfactory LV pacing threshold and dramatic clinical improvement from effectual biventricular pacing.
Bi2O3–MoO3 Binary System: An Alternative Ultralow Sintering Temperature Microwave Dielectric
Authors: Zhou Di , Wang Hong , Pang Li‐Xia , Randall Clive A. , Yao Xi
Published: July 2009

Preparation, phase composition, microwave dielectric properties, and chemical compatibility with silver and aluminum electrodes were investigated on a series of single‐phase compounds in the Bi2O3–MoO3 binary system. All materials have ultralow sintering temperatures <820°C. Eight different xBi2O3–(1−x)MoO3 compounds between 0.2≤x≤0.875 were fabricated and the associated microwave dielectric properties were studied. The β‐Bi2Mo2O9 single phase has a positive temperature coefficient of resonant frequency (TCF) about +31 ppm/°C, with a permittivity ɛr=38 and Qf=12 500 GHz at 300 K and at a frequency of 6.3 GHz. The α‐Bi2Mo3O12 and γ‐Bi2MoO6 compounds both have negative temperature coefficient values of TCF∼−215 and ∼−114 ppm/°C, with permittivities of ɛr=19 and 31, Qf=21 800 and 16 700 GHz at 300 K measured at resonant frequencies of 7.6 and 6.4 GHz, respectively. Through sintering the Bi2O3–2.2MoO3 at 620°C for 2 h, a composite dielectric containing both α and β phase can be obtained with a near‐zero temperature coefficient of frequency TCF=−13 ppm/°C and a relative dielectric constant ɛr=35, and a large Qf∼12 000 GHz is also observed. Owing to the frequent difficulty of thermochemical interactions between low sintering temperature materials and the electrode materials during the cofiring, preliminary investigations are made to determine any major interactions with possible candidate electrode metals, Ag and Al. From the above results, the low sintering temperature, good microwave dielectric properties, chemical compatibility with Al metal electrode, nontoxicity and price advantage of the Bi2O3–MoO3 binary system, all indicate the potential for a new material system with ultralow temperature cofiring for multilayer devices application.
Photoluminescence Characteristics of Energy Transfer Between Eu3+and Bi3+in LiEu1−xBix (WO4)0.5(MoO4)1.5
Authors: Xie An , Yuan Ximing , Shi Yu , Wang Fengxiang , Wang Juanjuan
Published: July 2009

A series of novel red phosphors LiEu1−xBix (WO4)0.5(MoO4)1.5 (x=0, 0.05, 0.10, 0.15, 0.20, 0.30, 0.40, and 0.50) were synthesized by the conventional solid‐state reaction method. The spectrum and the crystal structure of the phosphors were characterized by Fluorescence spectrophotometry and X‐ray diffraction, respectively. The photoluminescent results show that all samples can be excited efficiently by UV (396 nm) and blue (467 nm) light and that they emit red light at 615 nm with line spectra, which are coupled well with the characteristic emissions from UVLED and blue light‐emitting diode (LED), respectively. There is an efficient energy transfer from Bi3+ to Eu3+ ions, leading to the emission intensity of Eu3+ being enhanced by 1.5 times, and even more when Bi3+ ions are introduced into LiEu (WO4)0.5(MoO4)1.5. The introduction of Bi3+ ions broadened the excitation band of the phosphor, and the optimum doping concentration is found to be 10 mol% of Bi3+.
Prognostic significance of apoptotic index in multiple myeloma patients treated by conventional therapy and novel agents, thalidomide and bortezomib
Authors: Minarik Jiri , Scudla Vlastimil , Ordeltova Marta , Bacovsky Jaroslav , Pika Tomas , Langova Katerina
Published: July 2009

Objective:  To assess the outcome of the measurement of apoptotic index in myeloma patients treated by conventional chemotherapy and novel drugs with biological mechanism of action, thalidomide and bortezomib.

Patients and methods:  In a cohort of 189 patients with newly diagnosed multiple myeloma from November 1997 through February 2008, we assessed the prognostic significance of plasma cell apoptotic index (PC‐AI) using annexin‐V. The whole group was subsequently divided according to treatment approach (conventional chemotherapy only vs. inclusion of novel drugs, thalidomide and bortezomib), and curves of overall survival were constructed.

Results:  In the whole group (n = 189), low levels of PC‐AI <4.5% significantly separated patients with unfavorable prognosis (median OS 16 vs. 38 months, P = 0.004). In patients treated with conventional chemotherapy only (n = 139) the results were similar (median OS 10 vs. 25 months, P = 0.02), and the apoptotic index maintained its significance even within the group of 50 patients treated also with novel drugs (median OS 30 vs. 54 months, P = 0.027). PC‐AI was found to be independent on both Durie‐Salmon staging system and the International Prognostic Index.

Conclusion:  Presented results suggest the use of apoptotic index by flow cytometry measurement as a fast and accessible method for prognostic stratification of myeloma patients in routine practice.
5‐MCA‐NAT does not act through NQO2 to reduce intraocular pressure in New‐Zealand white rabbit
Authors: Alarma‐Estrany Pilar , Crooke Almudena , Pintor Jesús
Published: July 2009

Abstract:  Solid data support the idea that the MT3 melatonin binding site is an enzyme, quinone reductase 2 (NQO2), rather than a membrane melatonin receptor. However, the melatonin analogue, 5‐methoxycarbonylamino‐N‐acetyltryptamine (5‐MCA‐NAT), reduces intraocular pressure (IOP) via MT3 melatonin receptors. Therefore, the aim of this work was to test whether the melatonin binding site, MT3, is indeed the enzyme NQO2 in New Zealand rabbit eyes. To investigate this, the action of several substrates and inhibitors for NQO2 was compared to 5‐MCA‐NAT in their ability to modify IOP. Also, the effect of 5‐MCA‐NAT on IOP produced after NQO2 silencing by means of a siRNA was determinated. Altogether, the results led us to conclude that the in vivo effect of the MT3 ligand 5‐MCA‐NAT on IOP is not mediated by the enzyme NQO2, suggesting the existence of another melatonin receptor.
The contribution of rewetting to vegetation restoration of degraded peat meadows
Authors: van Dijk J. , Stroetenga M. , van Bodegom P.M. , Aerts R.
Published: July 2009

Question: What is the contribution of a rise in groundwater level to vegetation restoration of degraded peat meadows compared to abandonment only?

Location: Abandoned peat meadows in the central part of The Netherlands.

Methods: Comparison of species composition and species abundance of vegetation and seed banks of reference and rewetted peat meadows, using plant trait and seed bank analysis.

Results: Vegetation of rewetted meadows shared on average only 27% of their species with the reference meadow, while this was 50% on average for species in the seed bank. Rewetted meadows had a lower total number of species and a lower number of wet grassland and fen species present in the vegetation, but had higher species richness per m2, although evenness was not affected. Rewetting increased the dominance of species of fertile and near neutral habitats, but did not result in an increase of species of wet or waterlogged habitats. Re‐wetted meadows were dominated by species relying mainly on vegetative reproduction and species with a low average seed longevity compared to the reference meadow.

Conclusion: Rewetting was not effective as a restoration measure to increase plant species diversity or the number of wet grassland and fen species in the vegetation. If no additional restoration management is applied, the seed bank will be depleted of seeds of species of wet grassland or fen habitats, further reducing the chances of successful vegetation restoration.
Some factors affecting successional change on uranium mine wastes: Insights for ecological restoration
Authors: Martínez‐Ruiz C. , Marrs R.H.
Published: July 2009

Question: Are growth form and dispersal‐mode replacement during vegetation succession in semi‐arid Mediterranean conditions affected by the starting quality of the substrate and by site aspect?

Location: Central‐western Spain.

Methods: We monitored successions on three waste materials left after uranium mining: unbroken waste, broken waste and wastes amended with a sandy material (Arkoses); both north and south aspects were also studied on each substrate.

Results: The substrate starting quality had the greatest influence on spontaneous succession, separating the poorer quality substrates (broken and unbroken wastes) from the better ones (Arkoses) and two reference communities (Topsoil and Dehesa). The importance of aspect was confirmed then within each substrate type. Most species with a short life span (mostly annuals and a few biennials), together with some woody species on Arkoses, showed no response to age (years following the deposition of new soil). Others short‐lived species declined over time on the poorer wastes but not on the better Arkoses. There was a tendency for life form replacement (from thero‐phytes to hemicryptophytes) during succession only on the poorer‐quality substrates. No dispersal‐mode replacement sequence was found.

Conclusion: Improving the abiotic conditions of the substrate had a great effect on vegetation succession, but this effect was modified by aspect. Aspect took longer to induce differences in floristic composition on the poorer substrates, where succession was slower. Some trends in species responses to successional change were found by considering species traits, particularly life‐form.
Assessing plant‐nutrient relationships in highly invaded Californian grasslands using non‐normal probability distributions
Authors: Gea‐Izquierdo Guillermo , Gennet Sasha , Bartolome James W.
Published: July 2009

Question:Is native species occurrence related to soil nutrients in highly invaded Californian annual grasslands? What is the best method to analyze this relationship, given that native species occur in very low numbers and are absent from many locations?

Location:California, USA.

Methods:We investigated the effects of soil characteristics and livestock grazing on native plant occurrence at 40 plots from six sites during the period 2003–2005. Low absolute cover (< 5.8%) of native species resulted in strongly skewed, zero‐inflated data sets. To overcome problems in the analysis created by non‐normality and correlations within plots, we used GLMs and GLMMs, either with a Poisson or a negative binomial distribution, to analyse native species richness andNassella pulchracover.

Results:N. pulchracover was strongly associated with low phosphorus in sandy soils, whereas native species richness was highest in soils with low available nitrogen (high C:N).

Conclusion:Under current conditions, phosphorus seems to be a critical factor influencing abundance ofN. pulchra. Low fertility soils may provide refugia for native species in highly invaded California grasslands as they may be below a threshold required for non‐native annuals to completely dominate. By using non‐normal distributions in linear models with random components, we report well fitted models with more accurately tested significant covariates.
Reinstatement of traditional mowing regimes counteracts population senescence in the rare perennial Primula vulgaris
Authors: Endels Patrick , Jacquemyn Hans , Brys Rein , Hermy Martin
Published: July 2009

Question: Traditional management of grassland verges or ditch banks included mowing as a way to provide additional harvesting of hay. Nowadays, such sites are often left unmanaged, as mowing verges is no longer profitable in modern agricultural systems. Are vulnerable plant species able to withstand competition with the surrounding vegetation and maintain viable populations under these circumstances? How do they respond to reinstatement of traditional mowing regimes?

Location: Oedelem, northwestern Belgium.

Methods: To investigate the effect of reinstatement of the rare perennial Primula vulgaris, demography and adult plant performance were monitored in a grassland verge between 1999 and 2003 under different mowing regimes. Year transitions between life stages were analysed with matrix population models. To disentangle the contributions of the deviations in different life stage transitions to the variation in overall population growth rate, life table response experiments were used.

Results: Both management and year had a strong impact on demographic traits of P. vulgaris. If plots were left unmanaged, lower plant performance and declining population growth rates were observed. While population growth rates differed significantly between mowing regimes, mowing of plots only in July did not differ from mowing in July and October in terms of vegetative and reproductive output of adults. Mowing twice a year appeared to be most efficient in increasing population growth rate both by raising recruitment and growth of individuals into large reproductive adults.

Conclusions: Large P. vulgaris populations show a good ability to recover from recent abandonment of traditional management regimes. By mowing twice a year, managers are able to target vital rates that are most influential: growth and flowering of adult individuals.
Vegetation classification, mapping, and monitoring at Voyageurs National Park, Minnesota: An application of the U.S. National Vegetation Classification
Authors: Faber‐Langendoen Don , Aaseng Norm , Hop Kevin , Lew‐Smith Michael , Drake J.
Published: July 2009

Question:How can the U.S. National Vegetation Classification (USNVC) serve as an effective tool for classifying and mapping vegetation, and inform assessments and monitoring?

Location:Voyageurs National Park, northern Minnesota, U.S.A and environs. The park contains 54 243 ha of terrestrial habitat in the sub‐boreal region of North America.

Methods:We classified and mapped the natural vegetation using the USNVC, with ‘alliance’and ‘association’as base units. We compiled 259 classification plots and 1251 accuracy assessment test plots. Both plot and type ordinations were used to analyse vegetation and environmental patterns. Color infrared aerial photography (1:15840 scale) was used for mapping. Polygons were manually drawn, then transferred into digital form. Classification and mapping products are stored in publicly available databases. Past fire and logging events were used to assess distribution of forest types.

Results and Discussion:Ordination and cluster analyses confirmed 49 associations and 42 alliances, with three associations ranked as globally vulnerable to extirpation. Ordination provided a useful summary of vegetation and ecological gradients. Overall map accuracy was 82.4%.Pinus banksiana ‐ Picea marianaforests were less frequent in areas unburned since the 1930s.

Conclusion:The USNVC provides a consistent ecological tool for summarizing and mapping vegetation. The products provide a baseline for assessing forests and wetlands, including fire management. The standardized classification and map units provide local to continental perspectives on park resources through linkages to state, provincial, and national classifications in the U.S. and Canada, and to NatureServe's Ecological Systems classification.
Restoration of grazing management and its effect on vegetation in an upland grassland
Authors: Pavlů Vilém , Hejcman Michal , Pavlů Lenka , Gaisler Jan
Published: July 2009

Question: How are plant species and functional group composition, and potential sward height affected by implementation of different grazing regimes on previously abandoned semi‐natural grassland?

Location: The Jizerské mountains, northern Czech Republic.

Methods: We established a randomized block experiment with the following treatments: unmanaged control (U), intensive (IG) and extensive (EG) continuous grazing, first cut followed by intensive (ICG) and first cut followed by extensive (ECG) continuous grazing for the rest of the growing season. The percentage cover of all vascular plant species was recorded in 40 permanent plots.

Results: Total plant species richness increased in all managed treatments, whereas species number was reduced in U at the end of the experiment. Tall forbs (Aegopodium podagraria, Galium album, Anthriscus sylvestris, Cirsium arvense) as well as tall grasses (Elytrigia repens and Alopecurus pratensis) were more abundant in U. Species associated with both grazing treatments (IG, EG) were Dactylis glomerata, Festuca rubra agg. and Phleum pratense. Agrostis capillaris, Taraxacum spp., Trifolium repens, Ranunculus repens and Cirsium vulgare were promoted by ECG and ICG. Abundance of tall grasses and tall forbs reflected the intensity of management in the order U>EG, ECG>IG, ICG. Prostrate forbs, on the other hand, increased their cover with increasing intensity: ICG>IG>ECG>EG.

Conclusions: Plant species composition of semi‐natural grasslands is affected by the defoliation regime. Continuous grazing on abandoned grassland alters the sward structure towards a permanent pasture with short, light‐sensitive grasses and prostrate forbs. To maintain or enhance plant species richness in semi‐natural grasslands, understanding the effects of different grazing regimes on plant species composition is necessary.
Plant community establishment in a restored wetland: Effects of soil removal
Authors: Hausman Constance E. , Fraser Lauchlan H. , Kershner Mark W. , de Szalay Ferenc A.
Published: July 2009

Question: This study investigated the establishment of wetland plant assemblages following soil removal and restored hydrology in a former agricultural field. The following questions were posed. Does plant community composition differ as a result of soil removal? Does soil removal reduce the frequency of non‐wetland plants? Does soil removal reduce the frequency of non‐native invasive plants?

Location: The Panzner Wetland Wildlife Reserve (PWWR) in Summit County, northeastern Ohio, USA.

Methods: During 2000–2001, restoration was conducted on two adjoining fields (3.9 ha total) by excavating the upper 40–50 cm of soil layer and establishing 12 10 m × 10 m undisturbed control plots. Preliminary data included seed bank composition and soil organic matter, estimated from three different soil depths on the control plots. In spring 2004, a 10 m × 10 m soil‐removed plot was established adjacent to each control plot. Plant percent cover of all species was estimated within the center 5 m × 5 m of every plot. Above‐ground biomass of all species from three 0.25‐m2 quadrats was collected. Environmental water measurements included water depth, temperature, dissolved oxygen, pH, and conductivity.

Results: The top 10 cm of soil contained the most seeds, the highest species diversity, the greatest proportion of annual to perennial plants, and the lowest organic content. Obligate and facultative wetland plants were found in soil‐removed plots while facultative upland and upland plants were found in control plots. The only plots with arable weeds were the control plots. However, plant communities on soil‐removed plots in the North field, which had a higher elevation (ca. 15–20 cm), had a different species composition than soil‐removed plots in the South field.

Conclusions: The results of a controlled, replicated large‐scale study on the effects of soil removal showed that soil removal altered both the biotic and abiotic environment, but that the proximity to the water table was the primary controlling factor in the assembly of plant communities.
Impact of sheep grazing on nutrient budgets of dry heathlands
Authors: Fottner S. , Härdtle W. , Niemeyer M. , Niemeyer T. , von Oheimb G. , Meyer H. , Mockenhaupt M.
Published: July 2009

Questions: What effect does sheep grazing have on the nutrient budgets of heathlands? Can grazing compensate for atmospheric nutrient loads in heathland ecosystems? What are the conclusions for heathland management?

Location: Lüneburg Heath, NW Germany.

Methods: During a one‐year grazing experiment (stocking rate 1.1 sheep/ha) nutrient balances for N, Ca, K, Mg and P were calculated by quantifying input rates (atmospheric deposition, sheep excrement) and output rates (biomass removal, leaching).

Results: Atmospheric nutrient deposition amounted to 22.8 kg.ha−1.a−1 for N and < 0.2 kg.ha−1.a−1 for P. Sheep excrement increased the inputs for N and P by ca. 3.5 and 0.2 kg.ha−1.a−1, respectively. Grazing reduced N‐ and P‐stores in the above‐ground biomass by 25.6 and 1.9 kg.ha−1.a−1, respectively. N‐and P‐losses via leaching amounted to 2.2 and < 0.2 kg.ha−1.a−1. Output:input ratios for P were high, indicating that grazing severely affected P‐budgets of heaths.

Conclusions: Our results suggest that sheep grazing has the potential to compensate for atmospheric nutrient loads (particularly for current N deposition rates). However, in the long term the combination of elevated N‐deposition and P‐loss due to grazing may cause a shift from N‐(co‐) limited to more P‐(co‐) limited plant growth. To counteract an aggravation of P‐deficiency in the long term, grazing may be combined with management measures that affect P‐budgets to a lesser extent (e.g. prescribed burning).
Characterization of diverse plant communities in Aspen Parkland rangeland using LiDAR data
Authors: Su Jason G. , Bork Edward W.
Published: July 2009

Question: How effective is high‐resolution airborne LiDAR technology for quantifying biophysical characteristics of multiple community types within diverse rangeland environments?

Location: Native Aspen Parkland vegetation in central Alberta, Canada.

Methods: Vegetation within 117 reference plots stratified across eight types, including forest, shrubland, upland grassland and lowland meadow communities, were assessed in 2001 for the height, cover and density of vegetation within various strata (herb, shrub and tree layers). Actual ground data were subsequently compared against modelled values for each community type and strata derived from the analysis of airborne LiDAR data obtained in 2000.

Results: LiDAR data were effective for quantifying vegetation height, cover and density of the overstory within closed‐ and open Populus forest communities. However, LiDAR measurements typically underestimated the height and cover of shrublands, as well as most of the herbaceous communities. Analysis of LiDAR intensity data indicated reflectance generally decreased as LiDAR sampling points moved upwards from the ground to the vegetation canopy.

Conclusions: While LiDAR technology is useful for characterizing deciduous forest properties, the quantification of understory vegetation characteristics, as well as those of individual shrublands and grasslands, was more limiting. Further refinements in analysis methods are necessary to increase the reliability of characterizing these communities.
Effects of chronic herbivory and historic land use on population structure of a forest perennial, Trillium catesbaei
Authors: Jenkins Michael A. , Webster Christopher R. , Rock Janet H.
Published: July 2009

Question:How have long‐term herbivory and past land use impacted the population structure ofTrillium catesbaei, a long‐lived rhizomatous herb?

Location:Western Great Smoky Mountains National Park, Tennessee, USA.

Methods:We examinedT. catesbaeipopulations at three sites: (1) Cades Cove (CC), an area of intensive historic land use that has been maintained as open fields and woodlots with a history of chronic deer herbivory, (2) Whiteoak Sink (WOS), a reference area with similar land‐use history, geology, and soils that has succeeded to closed‐canopy forest with relatively low levels of deer herbivory, and (3) Leadbetter Ridge (LBR), an area of primary forest that has never received significant anthropogenic disturbance.Trillium catesbaeiis the most commonTrilliumspecies at the three study sites, but smaller in stature, shorter lived, and more of a habitat generalist.

Results:Chronic herbivory in CC has created a highly‐truncated age structure with no plants older than 9 years, while plant ages at the other sites were more evenly distributed. Compared to WOS, plants in CC were younger at a given height and more likely to flower when younger. Across all life stages, populations at CC contained 68 × fewer plants than WOS. The age structures of WOS and LBR were similar. Compared to published age estimates for otherTrilliumspecies, our results suggest thatT. catesbaeiis relatively short lived within the genus.

Conclusions:Chronic herbivory had pronounced effects on the population structure of a perennial herb. Other long‐lived herbaceous species may exhibit similar truncated age structures and flowering by younger and smaller plants. Habitat generalist species within a genus, such asT. catesbaei, that are able to reproduce more quickly may persist longer under chronic herbivory. However, chronic herbivory has likely caused the loss of herbaceous species from CC and may eventually cause the local extirpation ofT. catesbaeipopulations.
The interrelationship between productivity, plant species richness and livestock diet: a question of scale?
Authors: Süss Karin , Storm Christian , Zimmermann Kai , Schwabe Angelika
Published: July 2009

Question: What relationship exists between productivity, plant species richness and livestock diet? Are the results dependent on scale?

Location: A sheep‐grazed Koelerio‐Corynephoretea sandy habitat of the northern upper Rhine (Germany) as a low productivity model system.

Methods: The investigation was carried out for three years at a fine scale (2 m2) and for two years at a broad scale (79 m2). Productivity was measured by means of weighed above‐ground phytomass for fine scale and colour‐infrared (CIR) aerial photographs of the same system for fine and broad scales. For both scales, total numbers of vascular plant species and numbers of endangered vascular plant species were extracted from current vegetation relevés. Additionally, we obtained data on livestock diet (grazed phytomass, crude protein content).

Results: Statistical analyses show an influence of the year on all variables; relationships between variables are not significant in every year. Species richness and number of endangered species are negatively related to productivity at fine scale while crude protein content and grazed phytomass are positively related to productivity. At the broad scale the diversity‐productivity relationship shows a ‘hump’ with highest species numbers in middle pioneer stages; numbers of endangered species are highest in all pioneer stages.

Conclusions: We found a strong impact of scale and year on the diversity‐productivity relationship. It is inappropriate to analyse only small plots (2 m2), and it is necessary to study different years. This vegetation complex is dependent on grazing impact; thus there is an inversely proportional relationship between nature conservation value (high diversity) and livestock nutrition.
Long‐term dynamics in a planted conifer forest with spontaneous ingrowth of broad‐leaved trees
Authors: Goris Robbie , Kint Vincent , Haneca Kristof , Geudens Guy , Beeckman Hans , Verheyen Kris
Published: July 2009

Question: What are the age structure and growth trends in a 160‐year old not‐managed Pinus sylvestris plantation with spontaneous development of Quercus robur and can recruitment of Q. robur be related to the radial growth pattern of the P. sylvestris overstorey?

Location: Mattemburgh forest reserve, The Netherlands.

Methods: Throughout the forest, we sampled 103 oaks and 102 pines with an increment corer. Tree ring widths were measured and cross‐dated to produce mean ring width series. With these data we determined tree ages, investigated growth trends and identified growth releases and suppressions.

Results:
Q. robur is uneven‐aged: some individuals recruited around 1925, but most reached coring height in the 1940s. The latter recruitment period related to a transition from stressed to released growth of the overstorey pines, growth releases of the oldest Q. robur and occurrence of P. sylvestris regeneration. No further recruitment has taken place since 1950.

Conclusions: This study demonstrates that an old pine plantation can develop spontaneously into well‐structured pine forest with an understorey of oak and pine. However, understorey recruitment in these forest types is not a continuous process and in this case a single allogenic canopy disturbance triggered its establishment.
Response of the moss Racomitrium lanuginosum to changes in sheep grazing and snow‐lie due to a snow‐fence
Authors: Scott David , Welch David , van der Wal René , Elston David A.
Published: July 2009

Question: What are the responses of Racomitrium lanuginosum moss to altered snow‐lie and sheep use?

Location:
ACarexbigelowii‐Racomitrium lanuginosum heath on a Scottish montane plateau affected since 1986 by a fenced ski corridor.

Methods: Permanent quadrats were set up along transects 45 m long perpendicular to the snow‐fence. Cover was assessed over a 12‐year period from 1990. Pellet‐group clearance counts provided data on sheep usage between 1990 and 1996. Snow‐lie was mapped in the springs of 1991–1996.

Results: The snow‐fence created a gradient in sheep use and altered the duration of snow‐lie. At the start of monitoring Racomitrium cover was lower immediately adjacent to the fence, and after 12 years its cover was significantly reduced within 10 m of the fence. Further away from the fence Racomitrium cover was relatively stable. The loss of Racomitrium was correlated both with increased snow‐lie and heavier sheep usage. Grass cover increased near the fence and was related to sheep use. Dicranum fuscescens responded differently to Racomitrium, increasing significantly near the fence.

Conclusions: We found that changes in snow‐lie and grazing pressure quickly brought about vegetation change in this montane ecosystem. Racomitrium was the most sensitive species to the changes in grazing and snow‐lie caused by the fence, having the biggest initial changes. Loss of Racomitrium permitted increases of species more resistant to grazing including Dicranum fuscescens and grasses.
What helps Opuntia stricta invade Kruger National Park, South Africa: Baboons or elephants?
Authors: Foxcroft L.C. , Rejmánek M.
Published: July 2009

Question: Is Opuntia stricta more frequent, and its patches larger, under trees suitable for baboon roosting? If so, does it mean that baboons are major dispersal agents and that plants established under these trees are important foci of Opuntia stricta spread?

Location: Skukuza, Kruger National Park, South Africa.

Method: We surveyed an area invaded by Opuntia stricta in the Skukuza region of KNP. The survey included plots under potential baboon roosting trees,plots under trees unlikely to support baboons,and paired randomly located open sites.

Results: The null hypothesis ‐tree‐Opuntia spatial independence – can be rejected for Acacia nilotica, but not for Spirostachys africana. Opuntia plants are positively associated with Acacia trees suitable for baboon roosting. However, there is no significant difference between frequency of Opuntia under Acacia trees suitable and unsuitable for baboon roosting.It appears that all Acacia trees can serve as nurse trees for Opuntia. Compared to plots under Acacia trees, frequencies of old and robust Opuntia plants are significantly higher in open areas and under dead trees.

Conclusions: While baboons may be responsible for long distance Opuntia dispersal (over km),their role is not detectable at a local scale.On the other hand, elephants seem to contribute substantially to the local vegetative propagation of this species. Opuntia establishment and growth are more influenced by micro‐habitat than previously thought.
Flowering and seed production success along roads with different mowing regimes
Authors: Jantunen Juha , Saarinen Kimmo , Valtonen Ami , Saarnio Sanna
Published: July 2009

Question: Which one of the two mainly used mowing regimes along road verges, mowing once or twice a year is a better option regarding flowering and seed‐producing success of grassland species and plant species in general?

Location: Southeast Finland.

Methods: Plant species composition, flowering and seed production success were studied in road verges (1) mown once in August and (2) mown at the end of June and August. Flowering shoots were counted and phenological phases were estimated four times during a growing season.

Results: The numbers of flowering or seed‐producing species and shoots indicated that mowing once a year corresponding to the timing of traditional management was markedly better than mowing twice a year. The difference between the management groups was greatest at the end of July when the number of flowering species was 43% and the number of flowering and seed‐producing shoots 76% less after the first mowing than in the still unmown sites. The species avoided early cutting either through the timing of flowering or due to their growth form. Early season mowing had no effect on the occurrence and seed‐producing success of grassland species and the first flowering species. Seed production of grasses succeeded poorly in the verges mown twice.

Conclusion: Mowing once in August resulted in higher seed production in general, but mowing twice a season might be a better way to manage young verges on nutrient‐rich soils. The useful qualities of the management options should be considered locally when planning road verge management.