Innovation and firm growth: Does firm age play a role?

This paper explores the relationship between firm growth, innovation and firm age. We hypothesize that young firms undertake riskier innovation activities and are more oriented towards employment growth than towards harvesting returns in the form of sales growth. Using an extensive sample of Community Innovation Survey for the period 2004-2010, we apply quantile regressions and a Heckman sample selection technique to study the impact of R&D activities on firm growth according to firm age. Our results show that R&D intensity is positively associated with firm growth. However, for young firms R&D shows an increasing influence across the quantiles, while for old firms R&D shows a stable or perhaps decreasing effect over the quantiles. Firm age shows a significant negative impact among young firms, while for the sample of old firms the impact of firm age becomes non-significant. Our Heckman estimations show the evolution of the impact of the R&D on firm growth confirming a significant impact on sales and productivity growth, while the impact is negligible for employment growth. Keywords: firm age, firm growth, innovation, quantile regression. JEL CODES: L25, L20

Evaluation de la qualité de vie après prélèvement de la veine fémorale superficielle lors de reconstructions infra-inguinales [Quality of life after superficial femoral vein harvest for infra-inguinal reconstructions]

BACKGROUND: The superficial femoral vein (SFV) is a well-established alternative conduit for infra-inguinal reconstructivenous hypertension after SFV harvest may however result in significant morbidity. This study reports the efficiency of SFV as conduit for infra-inguinal reconstructions and characterize the anatomic and physiologic changes in harvest limbs and their relationship to the development of venous complications. METHODS: From May 1999 through November 2003, 23 SFV were harvested from 21 patients undergoing infra-inguinal reconstructions. Bypasses were controlled by regular duplex-ultrasound. The venous morbidity was assessed by measurements of leg circumferences, strain-gauge plethysmography and quality of life, investigated by the VEINES-QOL scale. RESULTS: At a mean follow-up of 10.4 months (range 1-56), primary, secondary patency and limb salvage rates of infra-inguinal bypasses using SFV are 71.4%, 76.2% and 85.7% respectively. No patient had major venous claudication. Oedema was significantly present in nine patients. Strain-gauge plethysmography showed outflow obstruction in all patients. The VEINES-QOL assessment showed no limitation in social and domestic activity, moderate complain about leg heaviness despite presence of oedema. CONCLUSION: The SFV harvest is a reliable conduit for infra-inguinal reconstructions and results in moderate venous morbidity in terms of functional consequences and quality of life.

Size-dependent predation by Dugesia lugubris (Turbellaria) on Physa acuta (Gastropoda): experiments and model

1. We investigated experimentally predation by the flatworm Dugesia lugubris on the snail Physa acuta in relation to predator body length and to prey morphology [shell length (SL) and aperture width (AW)]. 2. SL and AW correlate strongly in the field, but display significant and independent variance among populations. In the laboratory, predation by Dugesia resulted in large and significant selection differentials on both SL and AW. Analysis of partial effects suggests that selection on AW was indirect, and mediated through its strong correlation with SL. 3. The probability P(ij) for a snail of size category i (SL) to be preyed upon by a flatworm of size category j was fitted with a Poisson-probability distribution, the mean of which increased linearly with predator size (i). Despite the low number of parameters, the fit was excellent (r2 = 0.96). We offer brief biological interpretations of this relationship with reference to optimal foraging theory. 4. The largest size class of Dugesia (>2 cm) did not prey on snails larger than 7 mm shell length. This size threshold might offer Physa a refuge against flatworm predation and thereby allow coexistence in the field. 5. Our results are further discussed with respect to previous field and laboratory observations on P acuta life-history patterns, in particular its phenotypic variance in adult body size.

The occurrence of reptiles in Barn Owl diet in Europe

Capsule We present a review of the propensity to eat reptiles in the Barn Owl Tyto alba in Europe. Based on the analysis of 591 published studies reporting 3.07 million prey items identified in pellets, only 2402 reptiles (0.08%) were found. Reptiles were most often captured in southern parts of the European continent and on islands. A large proportion of the 1304 identified reptiles to the species level were nocturnal Gekkonidae (77.1%).

ROCK Inhibitor Enhances Adhesion and Wound Healing of Human Corneal Endothelial Cells.

Maintenance of corneal transparency is crucial for vision and depends mainly on the endothelium, a non-proliferative monolayer of cells covering the inner part of the cornea. When endothelial cell density falls below a critical threshold, the barrier and "pump" functions of the endothelium are compromised which results in corneal oedema and loss of visual acuity. The conventional treatment for such severe disorder is corneal graft. Unfortunately, there is a worldwide shortage of donor corneas, necessitating amelioration of tissue survival and storage after harvesting. Recently it was reported that the ROCK inhibitor Y-27632 promotes adhesion, inhibits apoptosis, increases the number of proliferating monkey corneal endothelial cells in vitro and enhance corneal endothelial wound healing both in vitro and in vivo in animal models. Using organ culture human cornea (N = 34), the effect of ROCK inhibitor was evaluated in vitro and ex vivo. Toxicity, corneal endothelial cell density, cell proliferation, apoptosis, cell morphometry, adhesion and wound healing process were evaluated by live/dead assay standard cell counting method, EdU labelling, Ki67, Caspase3, Zo-1 and Actin immunostaining. We demonstrated for the first time in human corneal endothelial cells ex vivo and in vitro, that ROCK inhibitor did not induce any toxicity effect and did not alter cell viability. ROCK inhibitor treatment did not induce human corneal endothelial cells proliferation. However, ROCK inhibitor significantly enhanced adhesion and wound healing. The present study shows that the selective ROCK inhibitor Y-27632 has no effect on human corneal endothelial cells proliferative capacities, but alters cellular behaviours. It induces changes in cell shape, increases cell adhesion and enhances wound healing ex vivo and in vitro. Its absence of toxicity, as demonstrated herein, is relevant for its use in human therapy.

Covariation between plumage colour polymorphism and diet in the Barn Owl Tyto alba

Several hypotheses might explain the evolution and maintenance of colour morphs within animal populations. The 'alternative foraging strategy' hypothesis states that alternative colour morphs exploit different ecological niches. This hypothesis predicts that morphs differ in diet, either because foraging success on alternative prey species is morph-dependent or because differently coloured individuals exploit alternative habitats. I examined this prediction in the Barn Owl Tyto alba, a bird that varies in plumage coloration continuously from dark reddish-brown to white. On the European continent, Owls are light-coloured (subspecies T. a. alba) in the south and reddish-brown (T. a. guttata) in the north; in central Europe the two subspecies interbreed, generating many colour variants. If plumage coloration indicates alternative foraging strategies, in sympatry dark- and light-coloured owls should consume prey species that are typical of the diets of T. a. guttata and T. a. alba in allopatry, respectively. In line with this prediction, both in allopatry and in sympatry in Switzerland T. a. guttata fed primarily upon Common Voles Microtus arvalis and T. a. alba upon Wood Mice Apodemus spp. Statistical analyses suggest that morph-dependent diet did not arise from a non-random habitat distribution of owls with respect to plumage coloration. This suggests that foraging success upon alternative prey is morph-dependent.

Trait decoupling promotes evolutionary diversification of the trophic and acoustic system of damselfishes.

Trait decoupling, wherein evolutionary release of constraints permits specialization of formerly integrated structures, represents a major conceptual framework for interpreting patterns of organismal diversity. However, few empirical tests of this hypothesis exist. A central prediction, that the tempo of morphological evolution and ecological diversification should increase following decoupling events, remains inadequately tested. In damselfishes (Pomacentridae), a ceratomandibular ligament links the hyoid bar and lower jaws, coupling two main morphofunctional units directly involved in both feeding and sound production. Here, we test the decoupling hypothesis by examining the evolutionary consequences of the loss of the ceratomandibular ligament in multiple damselfish lineages. As predicted, we find that rates of morphological evolution of trophic structures increased following the loss of the ligament. However, this increase in evolutionary rate is not associated with an increase in trophic breadth, but rather with morphofunctional specialization for the capture of zooplanktonic prey. Lineages lacking the ceratomandibular ligament also shows different acoustic signals (i.e. higher variation of pulse periods) from others, resulting in an increase of the acoustic diversity across the family. Our results support the idea that trait decoupling can increase morphological and behavioural diversity through increased specialization rather than the generation of novel ecotypes.

A pedicled bone graft from the acromion: an anatomical investigation regarding surgical feasibility.

OBJECTIVE: To investigate the technical feasibility of harvesting a vascularized bone graft from the acromion pedicled on the acromial branch. BACKGROUND: Complex fractures of the proximal humerus may result in partial or total avascular necrosis of the head fragment. Treatment of avascular necrosis of the humeral head is dependent upon the stage of disease as well as the dimension and location of necrosis. In general, the outcome is poor and complete restoration of the shoulder function is rarely attained. Contrary to osteonecrosis of carpal bones (where vascularized bone grafts have been routinely carried out for decades), reports of analogous procedures at the humeral head are anecdotal. METHODS: Based on selective post-mortem computer-tomographic angiography of 5 and the dissection of 30 embalmed human cadaver shoulders, we describe the anatomy of the acromial branch of the thoracoacromial trunk. The main focus was the constancy of its anatomical course, its dimensions and potential use as a nutrient vessel for a pedicled bone graft from the acromion. RESULTS: The course of the acromial branch revealed a constant topographic relationship to anatomical landmarks. Its terminal branches reliably supplied the anterior part of the acromion. The vascularized bone graft could be sufficiently mobilized to allow tension-free transfer to the humeral head as well as to the lateral two-thirds of the clavicle. CONCLUSION: We demonstrated the feasibility of vascularized bone graft harvesting from the acromion. This technique could be a joint-preserving procedure for osteonecrosis of the humeral head or may assist in the revision of a clavicular pseudoarthrosis.

Pheomelanin-based colouration is correlated with indices of flying strategies in the barn owl

Resource polymorphism refers to individuals from the same population foraging in alternative habitats or on alternative food. Food specialization can be associated with adaptations such as colour polymorphism, with pale and dark colours conferring differential camouflage in different habitats. Pale and dark-reddish pheomelanic Barn Owls (Tyto alba) forage on different prey species in closed and open habitats, respectively. We show here that darker-reddish owls have heavier stomach content when found dead, and their 5th secondary wing feather is more deeply anchored inside the integument. These correlations suggest that their feathers bend less when flying, and that darker-reddish Barn Owls are able sustain more intense flying than their paler conspecifics.

Mouse alarm pheromone shares structural similarity with predator scents.

Sensing the chemical warnings present in the environment is essential for species survival. In mammals, this form of danger communication occurs via the release of natural predator scents that can involuntarily warn the prey or by the production of alarm pheromones by the stressed prey alerting its conspecifics. Although we previously identified the olfactory Grueneberg ganglion as the sensory organ through which mammalian alarm pheromones signal a threatening situation, the chemical nature of these cues remains elusive. We here identify, through chemical analysis in combination with a series of physiological and behavioral tests, the chemical structure of a mouse alarm pheromone. To successfully recognize the volatile cues that signal danger, we based our selection on their activation of the mouse olfactory Grueneberg ganglion and the concomitant display of innate fear reactions. Interestingly, we found that the chemical structure of the identified mouse alarm pheromone has similar features as the sulfur-containing volatiles that are released by predating carnivores. Our findings thus not only reveal a chemical Leitmotiv that underlies signaling of fear, but also point to a double role for the olfactory Grueneberg ganglion in intraspecies as well as interspecies communication of danger.

Bioclimatic constraints to Andean cat distribution: a modelling application for rare species

AimTo identify the bioclimatic niche of the endangered Andean cat (Leopardus jacobita), one of the rarest and least known felids in the world, by developing a species distribution model.LocationSouth America, High Andes and Patagonian steppe. Peru, Bolivia, Chile, Argentina.MethodsWe used 108 Andean cat records to build the models, and 27 to test them, applying the Maxent algorithm to sets of uncorrelated bioclimatic variables from global databases, including elevation. We based our biogeographical interpretations on the examination of the predicted geographic range, the modelled response curves and latitudinal variations in climatic variables associated with the locality data.ResultsSimple bioclimatic models for Andean cats were highly predictive with only 3-4 explanatory variables. The climatic niche of the species was defined by extreme diurnal variations in temperature, cold minimum and moderate maximum temperatures, and aridity, characteristic not only of the Andean highlands but also of the Patagonian steppe. Argentina had the highest representation of suitable climates, and Chile the lowest. The most favourable conditions were centrally located and spanned across international boundaries. Discontinuities in suitable climatic conditions coincided with three biogeographical barriers associated with climatic or topographic transitions.Main conclusionsSimple bioclimatic models can produce useful predictions of suitable climatic conditions for rare species, including major biogeographical constraints. In our study case, these constraints are also known to affect the distribution of other Andean species and the genetic structure of Andean cat populations. We recommend surveys of areas with suitable climates and no Andean cat records, including the corridor connecting two core populations. The inclusion of landscape variables at finer scales, crucially the distribution of Andean cat prey, would contribute to refine our predictions for conservation applications.

Nymphal development of Podisus nigrispinus (Heteroptera, Pentatomidae) preying on larvae of Anticarsia gemmatalis (Lepidoptera, Noctuidae) fed with resistant and susceptible soybeans

Nymphal development of the predator Podisus nigrispinus (Dallas) fed with a susceptible (UFV 16) or an insect resistant soybean genotype (IAC 17) and with larvae of the prey Anticarsia gemmatalis Hübner (Lepidoptera, Noctuidae) reared on these genotypes, was evaluated. Survival and duration of each instar and of total nymphal stage, besides weight of nymphs at the beginning of each instar and of adults of P. nigrispinus soon after emergence, were also evaluated. Nymphal survival of this predator was similar with both genotypes (64.41% for the UFV 16 and 72.88% for the IAC 17). Duration of second and fourth instars for nymphs that originated females, of fourth instar for those that originated males, of the nymphal period for males (20.21 and 17.94 days) and females (19.76 and 18.19 days) was longer on the IAC 17 than on the UFV 16. Weight of third instar nymphs (3.12 mg and 2.42 mg) for those that originated males and of fifth instar (26.20 mg and 23.86 mg) for those that originated females and female weight after emergence (65.76 mg and 58.68 mg) was lower with the IAC 17 than with the UFV 16. Sex ratio of P. nigrispinus was not affected by the resistant soybean IAC 17.

Tempo de busca e de manuseio de larvas de Chrysoperla externa (Hagen, 1861) (Neuroptera, Chrysopidae) alimentadas com Uroleucon ambrosiae (Thomas, 1878) (Hemiptera, Aphididae)

Searching and handling time of Chrysoperla externa (Hagen, 1861) (Neuroptera, Chrysopidae) larvae fed on Uroleucon ambrosiae (Thomas, 1878) (Hemiptera, Aphididae). The objective of this research was to determine the searching and handling times of three larval instars of C. externa fed on U. ambrosiae at densities of 30, 40 and 50 per vial, with the feeding of the larvae at the preceding instars being U. ambrosiae nymphs or Sitotroga cerealella (Olivier, 1819) eggs. The larvae were maintained at 25 ± 2 ºC, 70 ± 10% RH and a 14-h photophase. A completely randomized design in a 6 x 3 factorial scheme with 12 replicates was adopted. The shortest searching time was found for the 2nd and 3rd instar larvae of C. externa, and this parameter was variable depending on the feeding given to the larvae previously. The handling time was similar for the 1st, 2nd and 3rd instar larvae. The longest searching time was found at an aphid density of 30, as compared to densities of 40 and 50 prey, with which there were no significant differences. Prey density did not have any influence on handling time.

Potencial de alimentação de Chrysoperla externa (Hagen, 1861) (Neuroptera, Chrysopidae) em diferentes densidades de Uroleucon ambrosiae (Thomas, 1878) (Hemiptera, Aphididae)

Feeding potential of Chrysoperla externa (Hagen) (Neuroptera, Chrysopidae) in different densities of Uroleucon ambrosiae (Thomas) (Hemiptera, Aphididae). The feeding potential of 2nd and 3rd instar larvae of Chrysoperla externa (Hagen, 1861) in relation to different densities of 30, 40 and 50 nymphs of Uroleucon ambrosiae (Thomas, 1878) at 3rd and 4th instars was evaluated. The treatments were individualized into 2.5 cm in diameter and 8.5 cm tall flat bottom glass vials and maintained in a controlled environmental chamber at 25±2 ºC temperature, 70±10% RH and 14 h photophase. A completely randomized experimental design with 10 replications was used. The consumption of the prey nymphs by the predator larvae was evaluated after 1, 2, 4, 8, 16 and 24 h from the beginning of the experiment and at every subsequent 24 h period until 2nd instar larvae molted or 3rd instar larvae pupated. Results have shown that for 2nd instar larvae, during the 1 h to 24 h period, there was a decreasing prey consumption at the 30 and 40 prey densities. However an increase in the consumption at the 50 prey density was observed. After this period, C. externa larvae presented a progressive increase on nymphs consumption as a function of the prey density. The same occurred with de 3rd instar predator larvae in all treatments. When daily mean consumption was evaluated the predator/prey ratio was 1:23, 1:27 and 1:33 for 2nd instar larvae and 1:27, 1:33 and 1:41 for 3rd instar larvae at 30, 40 and 50 nymph densities, respectively.

Efeito da densidade de ninfas de Aphis gossypii Glover, 1877 (Hemiptera, Aphididae) no consumo alimentar e aspectos biológicos de Orius insidiosus (Say, 1832) (Hemiptera, Anthocoridae)

Effect of ninfal density of Aphis gossypii Glover, 1877 (Hemiptera, Aphididae) on feed consumption and biological aspects of Orius insidiosus (Say, 1832) (Hemiptera, Anthocoridae). The influence of different densities of A. gossypii (10, 20, 30, 40, 50, 60 nymphs/day) on consumption rate, development time, survival, and reproduction of Orius insidiosus (Say, 1832) was investigated. The trials were carried out in climatic chamber at 25 ± 1 °C, 70±10% RH, and photoperiod 12:12h (L:D). Consumption rates of nymphs and adults increased under a linear form as the densities of aphids increased. Development time was longest when reared in 10 nymphs density (15.4 days). Nymphal survival was different under the densities of A. gossypii and no significant difference for the periods of preoviposition (4.8 days) and oviposition (8.9 days) were found. The oviposition increased with the prey densities (2.00, 11.33, 10.67, 21.30, 17.89 and 53.38 eggs), as well as the viability: 0.00, 52.49, 57.86, 58.14, 50.11 and 72.89%, respectively. Nymphs of A. gossypii as prey were suitable for the complete development of O. insidiosus.