MARKET STRUCTURE IN BIOTECHNOLOGY: IMPLICATIONS FOR LONG-RUN COMPARATIVE ADVANTAGE

A country specializing in a high technology industry may find that excess returns stemming from innovation are reallocated overseas as foreign-based multinationals access ongoing domestic R&D through alliances with or acquisition of established domestic start-ups. Computer simulation illustrates this process in the context of the current US specialization in biotechnology. Keywords: Biotechnology, market structure, comparative advantageBiotechnology, market structure, comparative advantage, Research and Development/Tech Change/Emerging Technologies,

THE SOURCE OF COMPARATIVE ADVANTAGE IN THE BIOTECHNOLOGY INDUSTRY: A REAL OPTIONS APPROACH

Sources of heterogeneity within the process of R&D investment, such as international differences in the maximum per-period rate of investment and level of regulatory uncertainty, offer a plausible explanation for US comparative advantage in biotechnology. Using dynamic stochastic simulation, the results presented in this paper suggest US biotechnology firms may initiate more R&D projects, innovate earlier and more rapidly, persevere longer in the face of mounting R&D costs, and successfully complete more R&D projects than European firms.Comparative advantage, biotechnology, real options, Industrial Organization, Research and Development/Tech Change/Emerging Technologies,

Revisiting the Role of Neighbourhood Change in Social Exclusion and Inclusion of Older People

Objective. To explore how older people who are “aging in place” are affected when the urban neighbourhoods in which they are aging are themselves undergoing socioeconomic and demographic change. Methods. A qualitative case study was conducted in two contrasting neighbourhoods in Montréal (Québec, Canada), the analysis drawing on concepts of social exclusion and attachment. Results. Participants express variable levels of attachment to neighbourhood. Gentrification triggered processes of social exclusion among older adults: loss of social spaces dedicated to older people led to social disconnectedness, invisibility, and loss of political influence on neighbourhood planning. Conversely, certain changes in a disadvantaged neighbourhood fostered their social inclusion. Conclusion. This study thus highlights the importance of examining the impacts of neighbourhood change when exploring the dynamics of aging in place and when considering interventions to maintain quality of life of those concerned

Effet du débit sur la dynamique temporelle des algues périphytiques dans une rivière influencée par les activités agricoles

Le périphyton de la rivière Boyer Nord, une rivière affectée par les activités agricoles dans le sud du Québec (Canada), a été échantillonné toutes les deux semaines de la mi-mai à la fin septembre 1999 afin d'évaluer son évolution temporelle et d'identifier les variables potentielles qui le contrôlent. Les résultats montrent la grande variabilité temporelle de la biomasse périphytique (poids sec organique et chlorophylle a) et de la structure de la communauté de diatomées. La communauté d'algues benthiques dans la rivière Boyer était principalement composée de diatomées (Nitzschia, Cocconeis, Cymbella, Cyclotella), d'algues vertes (Scenedesmus, Pediastrum, Cosmarium, Closterium) et de cyanobactéries (Phormidium, Oscillatoria, Merismopedia). La pointe de débit observée durant la semaine précédant l'échantillonnage était fortement corrélée à plusieurs variables physico-chimiques (N-total, NH3-N, NO3-N, P-total, turbidité) et était le plus fortement corrélée aux changements temporels de la biomasse. La biomasse (chlorophylle a et poids sec organique) était négativement corrélée au phosphore total, ce qui reflète la relation avec le débit. Les changements temporels dans la composition spécifique des diatomées étaient régis par différentes variables physico-chimiques, selon les limites de tolérances et la valence écologique des espèces. Les algues périphytiques de cette communauté ont réagi aux variations de l'environnement à l'intérieur d'une période de 2 semaines puisque des changements majeurs dans la structure de l'assemblage de diatomées ont été observés lors de chaque échantillonnage. Ces observations montrent la forte variabilité de la biomasse et de la structure de la communauté périphytique dans les rivières enrichies par les éléments nutritifs et souligne l'influence majeure du débit dans ce type d'environnement.Periphyton in an agriculturally enriched river (Boyer River, Québec, Canada) was sampled from mid-May to the end of September 1999 to evaluate the temporal succession of periphyton and to identify potential controlling variables. The river is located on the south shore of the St. Lawrence River and discharges into it approximately 30 kilometres downstream (east) of Québec City. Land-use in the Boyer River watershed is 60% farmland and 40% forests. The site was chosen for its intense farming, accessibility and proximity to an automatic sampling station for water quality operated by the Québec Ministry of the Environment that continuously recorded pH, temperature, dissolved oxygen and discharge. Event water samples were collected for nutrients, turbidity, conductivity and suspended solids according to discharge. Periphyton growth was scraped every two weeks from rocks over a 10 meter reach, between mid-May and the end of September using a template, blade and toothbrush. Samples for chlorophyll a (Chl a) and ash-free-dry-weight (AFDW) were filtered on to Whatman GF/C glass fiber filters the same day and additional samples were preserved with paraformaldehyde-glutaraldehyde for taxonomic analysis. Chl a was extracted in 95% ethanol and quantified by spectrophotometry. AFDW was determined by drying the samples for 24 hours at 80ºC followed by combustion in a muffle furnace at 500ºC for 2 hours. Samples for diatom analysis were cleaned using a mixture of 1:1 sulphuric and nitric acid at 60°C and mounted on slides with Naphrax mounting medium. Diatoms were then identified and counted with a Zeiss Axiovert 10 inverted microscope at 1000X magnification. A minimum of 400 valves were enumerated for each sample. The presence of other algal constituents was also determined. Statistical analyses included Pearson correlations, stepwise regression analysis and analysis of variance.The chemical and physical properties of the river fluctuated substantially during the sampling season. Nutrient levels were consistently high with total N in the range of 1,2-7,2 mg/l and total P in the range of 0,07-0,37 mg/l, confirming the strong agricultural enrichment of the Boyer River. All measured nitrogen components (total-N, NH3-N, NO3-N) showed a decreasing trend during the sampling season while soluble reactive phosphorus (SRP), total dissolved P, conductivity, pH and temperature showed a general increase over the season. Oxygen levels were often well above or below saturation (29-176% of air equilibrium) indicating a strong biological influence on oxygen dynamics.Periphytic biomass (Chl a and AFDW) and diatom community structure showed major fluctuations over time. The temporal changes in biomass were most strongly correlated (negatively) with peak discharge during the preceding week (AFDW : r=-0,748, p < 0,05; and Chl a : r=-0,649, p < 0,05). This discharge variable was strongly correlated (positively) with several physico-chemical variables (total-N, NH3-N, NO3-N, total-P, turbidity). The negative correlation between biomass and total phosphorus suggested that algae in the Boyer River were not nutrient-limited. However, stepwise regressions showed that variations in diatom-specific composition over time were regulated by various physico-chemical variables linked to environmental preferences and tolerance of each species. Navicula seminulum, Navicula cf. subminusculus and Navicula saprophila were strongly influenced by the peak discharge during the week preceding the sampling (R2 =0,76, F(1,8) =25,7, p 0,001; R2 =0,66, F(1,8) =15,82, p < 0,05 and R2=0,55, F(1,8) =9,85, p < 0,05, respectively). Cymbella silesiaca, Cocconeis placentula, Cyclotella meneghiniana and Navicula saprophila were strongly correlated with temperature (R2 =0,58, F(1,8) =11,08, p < 0,05; R2 =0,61, F(1,8) =28,15, p 0,001; R2 =0,41, F(1,8) =5,65, p < 0,05 and R2 =0,59, F(1,8) =11,38, p < 0,005, respectively). Diatoma vulgaris was mostly influenced by suspended solids plus discharge (R2 =0,4, F(1,8) =5,38, p < 0,05; and R2 =0,86, F(1,7) =20,72, p < 0,005, respectively). The abundance of Navicula lanceolata was strongly correlated with conductivity (R2 =45, F(1,8) =6,55, p < 0,05) while that of Nitzschia spp. correlated with total dissolved phosphorus (R2 =49, F(1,8) =7,63, p < 0,05). No significant influence of the physico-chemical environment was observed on Navicula cryptocephala or Surirella brebissonii. Benthic algae in this nutrient-rich ecosystem responded to environmental variations within 2 weeks since major changes in community composition were observed between all sampling dates. Although diatom community structure changed markedly during the sampling season, most of the observed species are indicative of nutrient-enriched rivers and streams.The results of this study show the dynamic nature of periphyton communities in nutrient-enriched rivers and streams and underscore the importance of discharge as a regulator of biomass. The rapid shifts in community structure also imply that benthic algae can be used as a sensitive measure of environmental conditions in agriculturally impacted ecosystems

Cognitive-behaviour therapy and skilled motor performance in adults with chronic tic disorder

The first aim of the present study was to compare performance of people with tic disorders (TD) and controls on executive function and a range of skilled motor tests requiring complex performance, guided movements, hand co-ordination, and fine control of steadiness. The second aim was to investigate the effect of cognitive behaviour therapy (CBT) on motor performance. A total of 55 patients with TD were recruited at baseline from participants in a behavioural management programme. A comparison group of 55 patients suffering from a variety of habit disorders (HD) involving complex manual movements, were matched on age and level of education to 34 non-psychiatric controls. Participants were evaluated pre- and post-treatment and post-waitlist with a neuropsychological evaluation focusing on executive function (Wisconsin Card Sorting Test, WCST) and skilled motor performance (Purdue Pegboard, Hole Steadiness Test, and the Groove Test). Results revealed WCST scores in the normal range, while motor performance differed significantly on the Purdue Pegboard Tests in both TD and HD as compared to the control group. Cognitive-behavioural treatment selectively improved motor performance in both clinical groups compared to waitlist control, and this improvement related to clinical outcome measures

Glutamate Cysteine Ligase-Modulatory Subunit Knockout Mouse Shows Normal Insulin Sensitivity but Reduced Liver Glycogen Storage.

Glutathione (GSH) deficits have been observed in several mental or degenerative illness, and so has the metabolic syndrome. The impact of a decreased glucose metabolism on the GSH system is well-known, but the effect of decreased GSH levels on the energy metabolism is unclear. The aim of the present study was to investigate the sensitivity to insulin in the mouse knockout (KO) for the modulatory subunit of the glutamate cysteine ligase (GCLM), the rate-limiting enzyme of GSH synthesis. Compared to wildtype (WT) mice, GCLM-KO mice presented with reduced basal plasma glucose and insulin levels. During an insulin tolerance test, GCLM-KO mice showed a normal fall in glycemia, indicating normal insulin secretion. However, during the recovery phase, plasma glucose levels remained lower for longer in KO mice despite normal plasma glucagon levels. This is consistent with a normal counterregulatory hormonal response but impaired mobilization of glucose from endogenous stores. Following a resident-intruder stress, during which stress hormones mobilize glucose from hepatic glycogen stores, KO mice showed a lower hyperglycemic level despite higher plasma cortisol levels when compared to WT mice. The lower hepatic glycogen levels observed in GCLM-KO mice could explain the impaired glycogen mobilization following induced hypoglycemia. Altogether, our results indicate that reduced liver glycogen availability, as observed in GCLM-KO mice, could be at the origin of their lower basal and challenged glycemia. Further studies will be necessary to understand how a GSH deficit, typically observed in GCLM-KO mice, leads to a deficit in liver glycogen storage

Two-dimensional electron gas formation in undoped In[0.75]Ga[0.25]As/In[0.75]Al[0.25]As quantum wells

We report on the achievement of a two-dimensional electron gas in completely undoped In[0.75]Al[0.25]As/In[0.75]Ga[0.25]As metamorphic quantum wells. Using these structures we were able to reduce the carrier density, with respect to reported values in similar modulation-doped structures. We found experimentally that the electronic charge in the quantum well is likely due to a deep-level donor state in the In[0.75]Al[0.25]As barrier band gap, whose energy lies within the In[0.75]Ga[0.25]As/In[0.75]Al[0.25]As conduction band discontinuity. This result is further confirmed through a Poisson-Schroedinger simulation of the two-dimensional electron gas structure.Comment: 17 pages, 6 figures, to be published in J. Vac. Sci. Technol.

The XXL Survey VII: A supercluster of galaxies at z=0.43

The XXL Survey is the largest homogeneous and contiguous survey carried out with XMM-Newton. Covering an area of 50 square degrees distributed over two fields, it primarily investigates the large-scale structures of the Universe using the distribution of galaxy clusters and active galactic nuclei as tracers of the matter distribution. Given its depth and sky coverage, XXL is particularly suited to systematically unveiling the clustering of X-ray clusters and to identifying superstructures in a homogeneous X-ray sample down to the typical mass scale of a local massive cluster. A friends-of-friends algorithm in three-dimensional physical space was run to identify large-scale structures. In this paper we report the discovery of the highest redshift supercluster of galaxies found in the XXL Survey. We describe the X-ray properties of the clusters members of the structure and the optical follow-up. The newly discovered supercluster is composed of six clusters of galaxies at a median redshift z around 0.43 and distributed across approximately 30 by 15 arc minutes (10 by 5 Mpc on sky) on the sky. This structure is very compact with all the clusters residing in one XMM pointing; for this reason this is the first supercluster discovered with the XXL Survey. Spectroscopic follow-up with WHT (William Herschel Telescope) and NTT (New Technology Telescope) confirmed a median redshift of z = 0.43. An estimate of the X-ray mass and luminosity of this supercluster and of its total gas mass put XLSSC-e at the average mass range of superclusters; its appearance, with two members of equal size, is quite unusual with respect to other superclusters and provides a unique view of the formation process of a massive structure.Comment: A&A, accepted; special XXL issu

The XXL Survey X: K-band luminosity - weak-lensing mass relation for groups and clusters of galaxies

We present the K-band luminosity-halo mass relation, $L_{K,500}-M_{500,WL}$, for a subsample of 20 of the 100 brightest clusters in the XXL Survey observed with WIRCam at the Canada-France-Hawaii Telescope (CFHT). For the first time, we have measured this relation via weak-lensing analysis down to $M_{500,WL} =3.5 \times 10^{13}\,M_\odot$. This allows us to investigate whether the slope of the $L_K-M$ relation is different for groups and clusters, as seen in other works. The clusters in our sample span a wide range in mass, $M_{500,WL} =0.35-12.10 \times 10^{14}\,M_\odot$, at $0<z<0.6$. The K-band luminosity scales as $\log_{10}(L_{K,500}/10^{12}L_\odot) \propto \beta log_{10}(M_{500,WL}/10^{14}M_\odot)$ with $\beta = 0.85^{+0.35}_{-0.27}$ and an intrinsic scatter of $\sigma_{lnL_K|M} =0.37^{+0.19}_{-0.17}$. Combining our sample with some clusters in the Local Cluster Substructure Survey (LoCuSS) present in the literature, we obtain a slope of $1.05^{+0.16}_{-0.14}$ and an intrinsic scatter of $0.14^{+0.09}_{-0.07}$. The flattening in the $L_K-M$ seen in previous works is not seen here and might be a result of a bias in the mass measurement due to assumptions on the dynamical state of the systems. We also study the richness-mass relation and find that group-sized halos have more galaxies per unit halo mass than massive clusters. However, the brightest cluster galaxy (BCG) in low-mass systems contributes a greater fraction to the total cluster light than BCGs do in massive clusters; the luminosity gap between the two brightest galaxies is more prominent for group-sized halos. This result is a natural outcome of the hierarchical growth of structures, where massive galaxies form and gain mass within low-mass groups and are ultimately accreted into more massive clusters to become either part of the BCG or one of the brighter galaxies. [Abridged]Comment: A&A, in pres