Temperature-dependent elasticity of microtubules

Central to the biological function of microtubules is their ability to modify their length which occurs by addition and removal of subunits at the ends of the polymer, both in vivo and in vitro. This dynamic behavior is strongly influenced by temperature. Here, we show that the lateral interaction between tubulin subunits forming microtubule is strongly temperature dependent. Microtubules deposited on prefabricated substrates were deformed in an atomic force microscope during imaging, in two different experimental geometries. Microtubules were modeled as anisotropic, with the Young's modulus corresponding to the resistance of protofilaments to stretching and the shear modulus describing the weak interaction between the protofilaments. Measurements involving radial compression of microtubules deposited on flat mica confirm that microtubule elasticity depends on the temperature. Bending measurements performed on microtubules deposited on lithographically fabricated substrates show that this temperature dependence is due to changing shear modulus, implying that the lateral interaction between the protofilaments is strongly determined by the temperature. These measurements are in good agreement with previously reported measurements of the disassembly rate of microtubules, demonstrating that the mechanical and dynamic properties of microtubules are closely related.

Cancers cutanés envahissant la base du crâne [Skin cancers infiltrating the skull base].

Squamous cell and basocellular carcinoma of the face have an excellent prognosis. Nevertherless, a small proportion therefore of these cancers differs by a much more aggressive behavior, caracterised by a tendency to infiltrate the deep facial soft tissues and facial bones. The invasion of the craniofacial skeleton and the intracranial structures follows the embryonic fusion lines or the facial sensitive or motor nerves, sometimes years after the initial treatment. The development of craniofacial surgery, reconstruction techniques and conformational radiotherapy allows us now to offer curative guided treatments, for these advanced staged tumors with a remaining limited prognosis. A therapeutic benefit implies a rigorous selection of these patients.

Introduced ants in Galápagos (Floreana Island) : importance of competition, coexistence and agressive behaviors

Abstract Invasive species represent with fragmentation of habitat the most serious threats to biodiversity in the world. Galápagos Archipelago, as most oceanic islands, suffers a high rate of introduced animals and plants that affect equilibrium and biodiversity of this unique biota. Ants rank among the most devastating invaders. Their social organization confer them a high ability to adapt and to spread in new environments forming rapidly populous communities. We studied the ant community of Floreana Island composed mainly of introduced species (at least 1 S). Introduction events occurred successively during last century. The last record is Monomorium destructor arrived in the eighties. Our aim is to investigate the modalities of interaction and coexistence of these introduced species. We highlighted the competition hierarchy of the coexisting species using attractive food baits. Two species behave as competitively dominant by monopolizing an important part of resources. They are M. destructor restricted to a small area and the fire ant Solenopsis geminata widely distributed on the island. Then we evaluated the relative importance of abiotic factors and interspecific competition in structuring the community. Ecological data were collected and presence and abundance of species were estimated using different methods in a wide range of habitats. Several species showed preferences either for arid or for humid areas. The little fire ant Wasmannia auropunctata, awell-known devastating species when introduced, was exclusively found in moist habitat in and around the agricultural area situated in the upper and central part of thé island. It coexists with other species in several parts but in a restricted perimeter it excludes all other ants and worker's density on the ground is nearly 70 times higher than ant's density in similar habitats occupied by several species. But most opportunist tramp species establish everywhere without particular ecological requirement. Analyses of species co-occurrences at various levels didn't reveal any marked effect of competition in structuring ant's assemblages. We supposed that the lack ofcompetition-derived structure has to be attributed to the dynamic of the system. Indeed, across the successive census of 1996, 2003, 2004 and 2005, species distributions and abundances appeared to be highly variables. In particular harsh conditions occurring in dry season in certain parts seem to be limiting to S. geminatai. We suggest that huge variations in the local distribution of the dominant S. geminata disrupt the community organization. Finally we conducted artificial ant confrontations to evaluate to what extend an aggressive behavior at the worker level maybe linked to the ecological success of a species on the island. S. geminata was rather indifferent when confronted to a submissive species on food sources, suggesting that its competitive dominance is largely due to a numerical superiority. On the other hand M. destructor exhibits a strong agonistic behavior in similar confrontations. As soon as the presence of a competitor is detected, most workers were observed to abandon foraging and to take part in physical aggressions. Since it is still restricted nearby its introduction spot two decades after its arrival, we suggest that the energetic cost of such an aggressive behavior prevent it to spread on that island already highly colonized. Dominant invasive species such as the fire ants S. geminata and W. auropunctata have negative impacts on Galápagos fauna, disturbing the hatching of land tortoises and birds. But very little is known about the impact of other exotic ants. Indeed, impact on arthropods and generally on ground-dwelling organisms is very diffcult to evaluate. As a consequence of the dynamic character of Floreana I. ant community it is difficult to build models or to málce predictions on evolution of introduced ant fauna. But Camponotus macilentus, an abundant endemic species seems today to be little affected by introduced ant species thanks to its strong interference competition ability and its preference for arid and harsh environments. Résumé Les espèces envahissantes représentent, avec la fragmentation du paysage, la plus grande menace pour la biodiversité. L'archipel des Galápagos, comme la plupart des îles du Pacifique, compte un grand nombre d'espèces introduites qui menacent la biodiversité de ce milieu unique.. Les fourmis sont parmi les envahisseurs les plus dévastateurs. Leur organisation sociale leur permet de s'adapter et de se propager pour devenir rapidement abondantes. Nous avons étudié la communauté de fourmis sur l'île de Floreana principalement composée d'espèces introduites (au moins 15). Les introductions se sont succédées au cours du siècle précédent. La dernière espèce recensée est Monomorium destructor introduite dans les années 80. Notre objectif est de mettre à jour les modalités des interactions et de la coexistence de ces espèces introduites. Nous avons mis en évidence la hiérarchie de compétition des différentes espèces à l'aide d'appâts de nourriture. Deux espèces se comportent de façon dominante en monopolisant une part importante des ressources. Ce sont M. destructor, restreintes à un petit périmètre, et la fourmi de feu Solenopsis geminata, largement distribuée sur l'île. Nous avons évalué l'importance relative des facteurs abiotiques et de la compétition interspécifique dans la structuration des peuplements. Des données écologiques ont été collectées et la présence et l'abondance des espèces ont été estimées à l'aide de trois méthodes au sein d'une grande diversité d'habitats. Plusieurs espèces .montrent des préférences soit pour les milieux humides, soit pour les milieux arides. La petite fourmi de feu Wasmannia auropunctata, une espèce connue pour être dévastatrice dans ses sites d'introduction, est présente exclusivement dans les habitats humides dans et à proximité de la zone agricole située dans la partie centrale de l'île. Elle coexiste en plusieurs points avec d'autres espèces mais au sein d'un périmètre restreint elle exclut toute autre fourmi et atteint des densités record au sol presque 70 fois supérieures aux densités de fourmis observées sur les sites voisins occupés par plusieurs espèces. Mais la plupart des espèces vagabondes opportunistes s'établissent partout sans exigences écologiques particulières. Des analyses de cooccurrence d'espèces à plusieurs niveaux n'ont pas révélé de rôle marqué de la compétition dans la structuration des communautés. Nous supposons que l'absence d'une telle structure doit être attribuée à la dynamique du système. En effet, au cours des différents recensements de 1996-1997, 2003, 2004 et 2005, la distribution et l'abondance des espèces était très variable. En particulier, les conditions rudes qui règnent dans la zone aride durant la saison sèche semblent affecter particulièrement S. geminata. Nous suggérons que de fortes variations dans la distribution de l'espèce dominante perturbent l'orgaiùsation des communautés. Finalement nous avons effectué des confrontations artificielles pour évaluer dans quelle mesure un comportement agressif au niveau de l'ouvrière peut être lié au succès écologique d'une espèce sur l'île. S. geminata montre très peu de réaction face à une espèce subordonnée sur une même source de nourriture, ce qui laisse supposer que sa dominance est largement due à sa supériorité numérique. Par contre, dans des conditions similaires, M. destructor est fortement agressive. En présence d'un compétiteur, la plupart des ouvrières renoncent très vite à leur activité de fourragement pour agresser les individus de l'autre espèce. Puisque deux décennies après son introduction elle est toujours confinée à son point d'arrivée, nous supposons que le coût en énergie et en ouvrières de ce comportement très agressif est un obstacle à son expansion sur cette île déjà fortement colonisée. Les espèces envahissantes dominantes comme les fourmis de feu S. geminata et W. auropunctata sont connues pour leur impact négatif sur la faune des Galápagos, entre autre sur les jeunes des tortues terrestres et des oiseaux. Mais nous savons très peu de choses sur l'impact des autres espèces de fourmis introduites. En effet, l'impact sur les arthropodes, et plus généralement sur la faune du sol, est très difficile à évaluer. En raison du caractère dynamique de la communauté de fourmi de Floreana, il est difficile de construire des modèles et de faire des prédictions sur l'évolution des peuplements de fourmis introduites. Mais Camponotus macilentus, une espèce endémique abondante, semble aujourd'hui peu affectée par les espèces introduites grâce à ses capacités de compétition par interférence et sa préférence pour les milieux arides. Resumen Las, especies invasoras representan, junto con la fragmentación del paisaje, la mayor amenaza para la biodiversidad. El archipiélago de Galápagos, como la mayoría de las islas del Pacífico, cuenta con un gran número de especies introducidas que amenazan la biodiversidad de este lugar único. Las hormigas son uno de los invasores más devastadores. Su organización social les permite adaptarse y propagarse para ser rápidamente abundante. Estudiamos la comunidad de hormigas de la isla Floreana principalmente compuesta de especies introducidas (al menos 15). Las introducciones se sucedieron durante el siglo anterior. La última especie contabilizada es Monomorium destructor introducida en los años 80. Nuestro objetivo es poner al día las modalidades de las interacciones y de la coexistencia de estas especies introducidas. Pusimos de relieve la jerarquía de competencia de las distintas especies con ayuda de cebos de comida. Dos especies se implican de manera dominante monopolizando una parte importante de los recursos. Son M. destructor, limitado a un pequeño perímetro, y la hormiga de fuego Solenopsis geminata; ampliamente distribuida por la isla. Evaluamos la importancia relativa de los factores abióticos y de la competencia interespecífica en la estructuración de la communidad. Se recogieron algunos datos ecológicos y se consideraron la presencia y la abundancia de las especies con ayuda de tres métodos en una gran diversidad de hábitats. Varias especies muestran preferencias o por los medios húmedos, o por los medios áridos. La pequeña hormiga de fuego Wasmannia auropunctata, una especie conocida por ser devastadora en sus lugares de introducción, está presente exclusivamente en los hábitats húmedos y cerca de la zona agrícola situada en la parte central de la isla. Coexiste en varios puntos con otras especies pero en un perímetro limitado excluye a cualquier otra hormiga y alcanza densidades en el suelo casi 70 veces superiores a las densidades de hormigas observadas en los lugares vecinos ocupados por varias especies. Pero la mayoría de las especies vagabundas oportunistas se establecen por todas partes sin exigencias ecológicas particulares. Análisis de cooccurrencía de las especies a varios niveles no revelaron una grande importancía de la competencia en la estructuración de las comunidades. Suponemos que la ausencia de tal estructura Bebé ser por la dinámica del sistema. Efectivamente, durante los distintos censos de 1996-1997, 2003,.2004 y 2005, la distribución ? la abundancia de las especies eran muy variables. En particular, las condiciones drásticas que reinan en la zona árida durante la temporada seca parecen afectar especialmente a S. geminata. Sugerimos que fuertes variaciones en la distribución de la especie dominante perturben la organización de las comunidades. Finalmente efectuamos confrontaciones artificiales para evaluar hastá que punto un comportamiento agresivo a nivel de la obrera puede explicar el éxito ecológico de una especie en la isla. S. geminata muestra muy poca reacción ante una especie subordinada mientras comparten la misma comida, lo que deja suponer que su dominancia se debe a su superioridad numérica. Por el contrario, en condiciones similares, M. destructor es muy agresivo. En presencia de otra especie, la mayóría de las obreras renuncian muy rápidamente a alimentarse para atacar a los individuos de la otra especie. Puesto que dos décadas después de su introducción todavía se confina en su punto de llegada, suponemos que el coste en energía y en obreras de este comportamiento muy agresivo es un obstáculo a su extensión en esta isla ya muy colonizada. Las especiés invasoras dominantes como las hormigas de fuego S. geminata y W. auropunctata son conocidas por su impacto negativo en la fauna de Galápagos, entre otras cosas sobre los juveniles de las tortugas terrestres y pájaros. Pero sabemos muy poco sobre el impacto de las otras especies de hormigas introducidas. Efectivamente es muy difïcil de evaluar el impacto en los artrópodos, y más generalmente en la fauna del suelo. Debido al carácter dinámico de la comunidad de hormiga de Floreana, es diEcil construir modelos y hacer predicciones sobre la evolución de las poblaciones de hormigas introducidas. Pero Camponotus macilentus, una especie endémica abundante, parece poco afectadá hoy por las especies introducidas gracias a sus capacidades de competencia por interferencia y su preferencia por los medios áridos.

Do pornographic websites influence boys' sexual behavior?

Purpose: To compare the sexual behavior of adolescent males who do and do not watch pornographic websites. Methods: This study was presented as a school survey. Data were drawn from the 2002 Swiss Multicenter Adolescent Survey on Health (SMASH02) database, a survey including 7,548 adolescents age 16-20. The setting was post-mandatory schools in Switzerland. A total of 2,891 male students who connected to the internet in the last 30 days were enrolled and distributed into two groups: boys who deliberately watched pornographic websites in the last 30 days (n ¼ 942; 33%) and boys who did not (n ¼ 1,949; 67%). Socio-demographic characteristics; frequency of connection to the internet; sexual behavior parameters (having a girlfriend and if yes, for more or less than 6 months; having had sexual intercourse; age at first sexual intercourse; use of a condom at last sexual intercourse; number of sexual partners; having made a partner pregnant). Results: A logistic regression was performed using STATA 9.2. The only significant socio-demographic variable was having a low socioeconomic status (adjusted odds ratio [AOR] 1.66); no difference was found for age and academic track between the two groups. Boys who watch pornographic websites were also significantly more likely to connect frequently to the internet (one day a week: AOR 1.75; several days a week: AOR 2.36; every day: AOR 3.11), to have had sexual intercourse (AOR 2.06), and to have had their first sexual intercourse before age 15 (AOR 1.48). The stability of the relationship with their girlfriend did not appear to have any influence on the search for pornography on the internet. Conclusions: About one third of boys in our sample report having accessed pornographic websites in the last 30 days, a proportion similar to other studies. Watching such websites increases with the frequency of connection to the internet and seems to be correlated with an earlier sexual activity debut among adolescent males. However, having had first sexual intercourse before age 15 is the only sexual risk behavior that seems to be increased when watching pornographic websites among boys. Further studies should address the causality of this correlation and the factors influencing the search for pornography on the web among boys, in order to explore some new ways of prevention about sexual risk behaviors. Sources of Support: The SMASH02 survey was carried out with the financial support of the Swiss Federal Office of Public Health and the participating cantons.

Do Mice Habituate to "Gentle Handling?" A Comparison of Resting Behavior, Corticosterone Levels and Synaptic Function in Handled and Undisturbed C57BL/6J Mice.

Study Objectives: "Gentle handling" has become a method of choice for 4-6 h sleep deprivation in mice, with repeated brief handling applied before sleep deprivation to induce habituation. To verify whether mice do indeed habituate was assess how 6 days of repeated brief handling impact on resting behavior, on stress, and on the subunit content of N-methyl-D-aspartate receptors (NMDARs) at hippocampal synapases, which is altered by sleep loss. We discuss whether repeated handling biases the outcome of subsequent sleep deprivation.Design: Adult C5BL/6J mice, maintained on a 12 h-12 h light-dark cycle, were left undistrubed for 3 days, then handled during 3 min daily for 6 days in the middle of the light phase. Mice were continuously monitored for their resting time serum conticosterona levels and synaptic NMDAR subunit composition were quantified.Results: Handling caused a similar to 25% reduction of resting time throughtout all handling days, After six, but not after one day of handling, mice had elevated serum corticosterone levels. Six-day handling augmented the presence of the NR2A subunit of NMDARs at hippocampal synapses.Conclusion: Repeated handling induces behavoir and neurochemical alterations that are absent in undisturbed animals. The presistently reduced resting time and the delayed increase in conticosterone levels indicate that mice do not habituate to handling over a 1-week period. Handling-induced modifications bias effects of gentle handling-induced sleep deprivation on sleep homeostasis, stress, glutamate receptor composition and signaling. A standardization of sleep deprivation procedures involving gengle handling will be important for unequivocally specifying how acute sleep loss affects brain function.

Frequency and effects of meeting health-behavior guidelines among adolescents

Objective: To assess the relationship between overweight status and the concomitant adherence to physical activity, daily screen time, and nutritional guidelines. Methods: Data were derived from the Swiss HBSC survey 2006. Participants (n=8130, 48.7% girls) were divided into two groups: normal-weight (n=7215, 44.8% girls), and overweight (n=915, 34.8% girls), using self-reported height and weight. Groups were compared on adherence to physical activity, screen time and nutritional guidelines. Bivariate analyses were carried out followed by multivariate analyses using normal-weight individuals as the reference category. Results: Regardless of gender, overweight individuals reported more screen time, less physical activity, and less concomitant adherence to guidelines. For boys, the multivariate analysis showed that any amount exceeding screen time recommendations was associated with increased odds of being overweight (>2-4h: adjusted odds ratio (AOR)=l .40; >4-6h: AOR=l .48; >6h: AOR=l .83). A similar relation was found for any amount below physical activity recommendations (4-6 times a week: AOR=1.67; 2-3 times a week: AOR=1.87; once a week or less: AOR=2.1). For girls, not meeting nutritional guidelines was less likely among overweight individuals (0-2 recommendations: AOR=0.54). Regardless of weight status, more than half of adolescents did not comply with any guideline and less than 2% met all 3 at the same time. Conclusions: Meeting current nutritional, physical activity and screen time guidelines should be encouraged with respect to overweight. However, as extremely low rates of concomitant adherence were found regardless of weight status, their achievability is questionable (especially for nutrition) which warrants further research to better adapt them to adolescents.

Haemodynamic consequences of changing potassium concentrations in haemodialysis fluids.

BACKGROUND: A rapid decrease of serum potassium concentrations during haemodialysis produces a significant increase in blood pressure parameters at the end of the session, even if effects on intra-dialysis pressure are not seen. Paradoxically, in animal models potassium is a vasodilator and decreases myocardial contractility. The purpose of this trial is to study the precise haemodynamic consequences induced by acute changes in potassium concentration during haemodialysis. METHODS: In 24 patients, 288 dialysis sessions, using a randomised single blind crossover design, we compared six dialysate sequences with different potassium profiles. The dialysis sessions were divided into 3 tertiles, casually modulating potassium concentration in the dialysate between the value normally used K and the two cut-off points K+1 and K-1 mmol/l. Haemodynamics were evaluated in a non-invasive manner using a finger beat-to-beat monitor. RESULTS: Comparing K-1 and K+1, differences were found within the tertiles regarding systolic (+5.3, +6.6, +2.3 mmHg, p < 0.05, < 0.05, ns) and mean blood pressure (+4.3, +6.4, -0.5 mmHg, p < 0.01, < 0.01, ns), as well as peripheral resistance (+212, +253, -4 dyne.sec.cm-5, p < 0.05, < 0.05, ns). The stroke volume showed a non-statistically-significant inverse trend (-3.1, -5.2, -0.2 ml). 18 hypotension episodes were recorded during the course of the study. 72% with K-1, 11% with K and 17% with K+1 (p < 0.01 for comparison K-1 vs. K and K-1 vs. K+1). CONCLUSIONS: A rapid decrease in the concentration of serum potassium during the initial stage of the dialysis-obtained by reducing the concentration of potassium in the dialysate-translated into a decrease of systolic and mean blood pressure mediated by a decrease in peripheral resistance. The risk of intra-dialysis hypotension inversely correlates to the potassium concentration in the dialysate. TRIAL REGISTRATION NUMBER: NCT01224314.

Aerodynamic drag modeling of alpine skiers performing giant slalom turns.

PURPOSE: Aerodynamic drag plays an important role in performance for athletes practicing sports that involve high-velocity motions. In giant slalom, the skier is continuously changing his/her body posture, and this affects the energy dissipated in aerodynamic drag. It is therefore important to quantify this energy to understand the dynamic behavior of the skier. The aims of this study were to model the aerodynamic drag of alpine skiers in giant slalom simulated conditions and to apply these models in a field experiment to estimate energy dissipated through aerodynamic drag. METHODS: The aerodynamic characteristics of 15 recreational male and female skiers were measured in a wind tunnel while holding nine different skiing-specific postures. The drag and the frontal area were recorded simultaneously for each posture. Four generalized and two individualized models of the drag coefficient were built, using different sets of parameters. These models were subsequently applied in a field study designed to compare the aerodynamic energy losses between a dynamic and a compact skiing technique. RESULTS: The generalized models estimated aerodynamic drag with an accuracy of between 11.00% and 14.28%, and the individualized models estimated aerodynamic drag with an accuracy between 4.52% and 5.30%. The individualized model used for the field study showed that using a dynamic technique led to 10% more aerodynamic drag energy loss than using a compact technique. DISCUSSION: The individualized models were capable of discriminating different techniques performed by advanced skiers and seemed more accurate than the generalized models. The models presented here offer a simple yet accurate method to estimate the aerodynamic drag acting upon alpine skiers while rapidly moving through the range of positions typical to turning technique.

Longer survival for patients with alternative lengthening of telomeres (ALT) glioblastoma multiforme is due to a less aggressive phenotype and not to improved response to adjuvant therapy

Introduction: The Alternative Lengthening of Telomeres (ALT) mechanism is a significant prognostic factor for longer survival in patients with GBM, irrespective of age. The reasons for this are unknown. We considered two possibilities; firstly that ALT identifies a subset of less aggressive GBMs, or alternatively, a group of tumours that respond more favourably to adjuvant therapy. Methods: ALT was determined by staining for ALT Associated PML Bodies (APBs) in archival tissue in a retrospective analysis of 573 GBM patients. IDH1 mutation was determined by immunohistochemistry in a subset of these. Results: We identified the presence of the telomerase-independent ALT in 15% of GBM patients and found that it correlated with survival (22% of ALT patients survive more than 2 years compared to 9% for non-ALT). This survival advantage was independent of surgery type (biopsy or full resection) and treatment (radiotherapy and chemotherapy). Interestingly ALT conferred a significant survival advantage for patients who only received surgery (13.3 months compared to 5.5 months) (19% vs 1% .2 year survival). This survival benefit was also observed in GBM patients who received surgery and radiotherapy (18.5% vs 2.4%. 2 year survival), but less so for chemotherapy (21% vs 17% . 2 year survival). For the ALT patients the fraction surviving more than 2 years did not improve significantly with adjuvant therapy. IDH1 mutation also associated with ALT. Conclusions: These data indicate ALT+ tumours are biologically distinct and associated with improved patient survival, probably due to less aggressive/invasive growth. However they respond poorly to current adjuvant treatment and therefore new therapies are urgently needed for this group.

Multisensory facilitation of behavior in monkeys: effects of stimulus intensity.

Multisensory stimuli can improve performance, facilitating RTs on sensorimotor tasks. This benefit is referred to as the redundant signals effect (RSE) and can exceed predictions on the basis of probability summation, indicative of integrative processes. Although an RSE exceeding probability summation has been repeatedly observed in humans and nonprimate animals, there are scant and inconsistent data from nonhuman primates performing similar protocols. Rather, existing paradigms have instead focused on saccadic eye movements. Moreover, the extant results in monkeys leave unresolved how stimulus synchronicity and intensity impact performance. Two trained monkeys performed a simple detection task involving arm movements to auditory, visual, or synchronous auditory-visual multisensory pairs. RSEs in excess of predictions on the basis of probability summation were observed and thus forcibly follow from neural response interactions. Parametric variation of auditory stimulus intensity revealed that in both animals, RT facilitation was limited to situations where the auditory stimulus intensity was below or up to 20 dB above perceptual threshold, despite the visual stimulus always being suprathreshold. No RT facilitation or even behavioral costs were obtained with auditory intensities 30-40 dB above threshold. The present study demonstrates the feasibility and the suitability of behaving monkeys for investigating links between psychophysical and neurophysiologic instantiations of multisensory interactions.

The Swiss Business Elite (1980-2000): How the Changing Composition of the Elite Explains the Decline of the Swiss Company Network

In this paper we analyse the decline of the Swiss corporate network between 1980 and 2000. We address the theoretical and methodological challenge of this transformation by the use of a combination of network analysis and multiple correspondence analysis (MCA). Based on a sample of top managers of the 110 largest Swiss companies in 1980 and 2000 we show that, beyond an adjustment to structural pressure, an explanation of the decline of the network has to include the strategies of the fractions of the business elites. We reveal that three factors contribute crucially to the decline of the Swiss corporate network: the managerialization of industrial leaders, the marginalization of law degree holders and the influx of hardly connected foreign managers.