The centers of gravity of the associahedron and of the permutahedron are the same

In this article, we show that Loday's realization of the associahedron has the the same center of gravity than the permutahedron. This proves an observation made by F. Chapoton. We also prove that this result holds for the associahedron and the cyclohedron as realized by the first author and C. Lange

Shrubs indirectly increase desert seedbanks through facilitation of the plant community

The mechanisms supporting positive ecological interactions are important. Foundation species can structure desert biodiversity by facilitating seedbanks of annual plants, but the direct and indirect mechanisms of shrub effects on seedbank have not been experimentally decoupled. We conducted the first test of shrubs increasing seedbank densities through direct effects on the seedbank (i.e. shrub seed-trapping, animal-mediated dispersal) and indirect effects by facilitating the annual plant community (i.e. seed deposition, annual seed-trapping). Two distinct desert ecosystems were used to contrast transient seedbank densities in shrub and open microsites by manipulating annual plant density and the presence of the persistent seedbank. We measured transient seedbank densities at the end of the growing season by collecting soil samples and extracting seeds from each respective treatment. Transient seedbank densities were greatest in shrub canopies and with relatively higher annual plant densities. The persistent seedbank contributed to transient seedbank densities only in one desert and in the open microsite. Shrubs indirectly increased seedbank densities by facilitation the seed production of the annual plants. Therefore, shrubs are increasing seedbank independently of the annual plant community, likely through trapping effects, and dependently by facilitating seed production of the annuals. These findings provide evidence for a previously undescribed mechanism that supports annual seedbanks and thus desert biodiversity. We also identify shrubs as being significant drivers of desert plant communities and emphasize the need to consider multiple mechanisms to improve our ability to predict the response of ecosystems to change.York University Librarie

L’évolution de l’action politique de la CSN

Les syndicats ouvriers ne peuvent pas rester étrangers à l'action politique. Celle-ci peut cependant prendre plusieurs formes. Dans cette étude l'auteur montre l'évolution de la CSN (autrefois CTCC) face à l'action politique.INTRODUCTIONThe political action of organized labor could be defined as the presence of unions in politics. But even if this presence may take different forms, one may say that it could be divided in two main categories : the partisan and the non-partisan political action. In addition to this, the non-partisan political action has two sub-groups which are the direct and the indirect non-partisan political action.The object of this paper is to show how the CNTU since its birth has practiced a non-partisan political action direct or indirect following the circumstances or the periods.THE CCCL AND THE POLITICAL ACTIONThe CCCL 1 does not want to accept any form of political partisanery in its organization and even forbids its President or Secretary General to have public commitments on politics.To prove this point allow me to quote two articles from « The Constitution and By-Laws of the CCCL, 1st edition, 1921 » :— art. III « The CCCL should never be affiliated to any political party ».— art. XXIX « Discussions of political partisanery will not be admitted in the confederal conventions ».But those decisions were misinterpreted by the other members and by the public. The choices made by the individuals were considered as those of the movement : the action of the individuals was identified to their union's. All of this led, in 1923, to a modification of the Constitution and article XXIX was replaced by article XXX which clearly separated the rights and duties of the movement itself from the individuals belonging to the movement.The CCCL did not modify its Constitution regarding political action until 1952.The attitude of the CCCL regarding political action could be summarized in 3 main points :a) In the first place, the CCCL does not see the ground of supporting a certain political party rather than another one.b) Regarding its members, the CCCL has always respected their own freedom.c) Being a representative movement, the CCCL wishes to have a role of watch-dog toward the government.In 1943, in Montreal, the CCL adopted an important resolution regarding political action. It decided to adopt the CCF as the political weapon of the workers. On the other hand, the TLC, in 1943 in Quebec City, decided to organize political action committees in order to allow local unions to play a more direct role in politics. Those two choices did not change the policies of the CCCL toward political action.We can therefore say that since its foundation, the CCCL has chosen to be entirely free from any political party. However the CCCL wishes to influence the government by a non-partisan political action in order to reach the main goal of unionism i.e. to defend and protect workers.THE POLITICAL ACTION OF THE CCCL (1949-1958)New AttitudeIn 1946, a new team was elected at the head of the CCCL and was immediately led to rethink the position of the Confederation toward political action for different reasons :1.—The decisions of the CCL and TLC toward their political action.2.—The anti-union attitude of the Government of Quebec.In fact the efficiency of the traditional position of the CCCL toward political action was called in question. So in 1949, it was decided that a committee of civic action should be created.This same committee became a year later the committee of political orientation. It was in the provincial election of July 1952 that this committee began a more direct action in politics by publishing a legislative program in 32 points. The committee went quite far in its action : for example were openly declared as enemies to unionism five candidates at the election.The CCCL was then accused of supporting a political party to the prejudice of the other. This accusation was discussed at the following convention in Shawinigan. In 1953, the committee publishes another paper entitled « Why the CCCL Interferes in Federal Politics ». The authors insisted on the great influence of the Federal Government on Canadian workers.It is to be noted it was the time of Duplessis regime, whose goals were quite different from those of the labor movement.The political action of the CCCL remains a non-partisan action but will work on two different levels. On the one hand, the committee will have the responsibility of giving the members a political education and on the other hand, it will have a direct action toward the government by supporting for election candidates who are thoughtful of the common good and responsive to the request of the labor movement.During the electoral campaign of 1956, the CCCL intensifies its political action. But the results of the campaign brought the old regime back and furthermore stronger than before.TransformationsIn 1956, one of the main events in the history of union organization in Canada happened : the merger of the TLC and of the CCL to create the Canadian Labour Congress. In 1959, in Winnipeg, a meeting was held to discuss the creation of a labor political party. Representatives of the CCCL were invited.This project of creation of a labor political party forced the CCCL to rethink its political action. Having always been opposed to this form of political action,the CCCL was not ready to reject the principle respected since its foundation. But a study of the problem was necessary and a readjustment possible.At the CCCL convention of 1959 in Quebec, major modifications were voted. It is still forbidden to the CCCL to be affiliated to a political party, but it can submit briefs to the governments, can study the effïciency of a political party, etc.This formula seems to give full freedom in the field of political action except for a partisan action. The most important step was to allow the President, and the Secretary general in the absence of the former, to have public commitments on politics on behalf of the CCCL.THE 1962 CONFRONTATION : CNTU - SOCIAL CREDITIn 1962, the CNTU decided to fight against the Social Credit Party because its philosophy was dangerous for the workers. Jean Marchand, then President of the CNTU, made many statements against this party and even confronted its leader on T.V. Those intervention of the President of the CNTU against the Social Credit during the electoral campaign brought up serious accusations from some members. He has been accused of violating the constitution of the CNTU by having done a partisan political action.Some other important changes were brought to the CNTU political action philosophy : the Confederal Bureau has been given the power of manifestating its preference, of denonciating or of declaring its neutrality toward a political party.After more than 40 years of existence, the CNTU had finally found a formula which gave all the possible lattitude for a non-partisan political action.CONCLUSIONAlways respecting the principle saying that union political action must not be partisan, the CNTU has found a formula by which its members, leaders, officers, its affiliated organizations and its Confederal Bureau remain entirely free regarding their political choice. The only restriction remaining is that these choice must never be against the general interests of the labor movement.( 1 ) Trade and Labour Congress of Canada : T.L.C. ; Canadian Congress of Labour : C.C.L. ; Canadian Labour Congress : C.L.C. ; Canadian and Catholic Confederation of Labour : C.C.C.L., which became Confederation of National Trade-Unions : C.N.T.U

A systematic review of arthropod community diversity in association with invasive plants

Invasive plants represent a significant financial burden for land managers and also have the potential to severely degrade ecosystems. Arthropods interact strongly with plants, relying on them for food, shelter, and as nurseries for their young. For these reasons, the impacts of plant invasions are likely strongly reflected by arthropod community dynamics including diversity and abundances. A systematic review was conducted to ascertain the state of the literature with respect to plant invaders and their associated arthropod communities. We found that the majority of studies did not biogeographically contrast arthropod community dynamics from both the home and away ranges and that studies were typically narrow in scope, focusing only on the herbivore feeding guild, rather than assessing two or more trophic levels. Importantly, relative arthropod richness was significantly reduced on invasive plant species. Phylogenetic differences between the invasive and local plant community as well as the plant functional group impact arthropod diversity patterns. A framework highlighting some interaction mechanisms between multiple arthropod trophic levels and native and invasive plants is discussed and future research directions relating to these interactions and the findings herein are proposed

Les diatomées de la mer de Goldthwait dans la région de Rivière-du-Loup, Québec

Les sédiments de la mer de Goldthwait de la région de Rivière-du-Loup ont livré une flore de diatomées subarctique comprenant 41 genres et 131 taxons. Cette micro-flore fossile se distingue de la flore actuelle par la rareté des espèces dulcicoles planctoniques, par l'abondance des formes polyhalobes méioeuryhalines et par le nombre restreint (32) de taxons communs. Les basses teneurs en valves des dépôts étudiés (<1 x 106valves par gramme) résultent surtout d'une biomasse médiocre accentuée par une forte sédimentation détritique. Un premier assemblage à Stephanopyxis turris var. intermedia et Coscinodiscus sp. 1 est attribué aux eaux profondes et salées de la phase pléni-marine. Le deuxième assemblage, défini par Cocconeis scutellum var. stauroneiformis, C. costata, Nitzschia cylindrus et Chaetoceros sp. 1 (soie), indique un milieu littoral et suggère que des conditions régressives moins profondes et moins salées ont pu prévaloir vers 10 500 ans BP. Le dernier assemblage marin à C. costata, Cyclotella caspia et C. scutellum var. stauroneiformis correspond à un milieu saumâtre et peu profond qui a pu exister localement durant la phase régressive. Les quelques diatomées tourbicoles relevées dans des sédiments marins suggère enfin une installation de la flore continentale dès 10 500 ans BP.In the Rivière-du-Loup area, the Goldthwait Sea deposits yielded a subarctic diatom flora including 41 genera and 131 taxa. This fossil microflora differs from the present one by its rare planktonic freshwater species, its frequent polyhalobous meioeuryhaline forms and few common taxa. Constant low valve values (less than 1 x 106valves by gram) are explained mainly by a weak diatom biomass and by a high fine sediment deposition rate. A first Stephanopyxis turris var. intermedia and Coscinodiscus sp. 1 assemblage is attributed to the deep and marine waters of the full-marine phase. The second one is a littoral assemblage defined by Cocconeis scutellum var. stauroneiformis, C. costata, Nitzschia cylindrus and Chaetoceros sp. 1 ; it indicates that shallower and less saline regressive conditions prevailed by 10,500 years BP. The last C. costata, Cyclotella caspia and C. scutellum var. stauroneiformis assemblage is likely to correspond to a local, very shallow and brackish environment related to the regressive phase. Finally, some bog species observed in dated marine sediments suggest that continental colonization by diatoms oc-cured by 10,500 years BP.In der Rivière-du-Loup Gegend (Québec), bilden die Diatomeen der Ablagerungen im Goldthwait Meer eine subarktische Flora von 131 Taxonen, die in 41 Gattungen eingeteilt sind. Die Diatomproben sind jedoch selten und der geringe Gehalt an Valven ùberschreitet nie 1 x 106 Valven per Gramm. Dièse Armut wird verschiedenen Faktoren zugeordnet, unter welchen die hauptsâchlichen eine mittelmâssige Primàrproduktion und eine reichliche, feine, detrische Sedimentation sind. Eine Zusammensetzung von Stephanopyxis turris var. intermedia et Coscinodiscus sp. 1 wird den tiefen Meeresgewâssern der plenimarinen Phase zugeordnet. Die Zusammensetzung von Cocconeis scutellum var. stauroneiformis, C. costata, Nitzschia cylindrus und Chaetoceros sp. 1 folgt ihr, und deutet auf eine weniger salzige Kùstenumgebung hin. Mit einem Alter von 10500 Jahren v.u.Z., bezeichnet sie die zurùckgehenden Umstànde, welche die plenimarine Phase beendeten. Eine letzte Zusammensetzung von C. costata und Cyclotella caspia bezieht sich auf die brackigen und sehr flachen Gewàsser derzurùckgehenden Phase

Les diatomées fossiles de deux tourbières ombrotrophes du Bas-Saint-Laurent, Québec

Les diatomées fossiles de deux tourbières ombrotrophes du Bas-Saint-Laurent, Québec, comprennent 34 genres et 143 taxons dont seulement 49 sont communs aux deux tourbières. La distribution stratigraphiques des taxons spécifiques et les associations de diatomées permettent d'observer l'évolution des tourbières étudiées. La tourbière à sphaignes de Rivière-du-Loup possède une flore fossile hydroterrestre et acidobionte (association à Eunotia paludosa et var. pumila et E. tenella) assez stable. Dans les 30 cm supérieurs, l'association mono-spécifique à E. paludosa var. pumila suggère un changement notable dans la végétation de sphaignes et un environnement écologique plus rigoureux. Les sédiments de la pessière à sphaignes de la tourbière du Fleuve contiennent une flore qui a probablement évolué depuis un milieu stagnant, franchement minérotrophe et légèrement acide (association à Cymbella aspera et Pinnularia cf. sfreptoraphe) à des conditions oligotrophes. acides et sub-aériennes (association à E. paludosa, Pinnularia aff. hilseana et P. subcapitata). Ces flores distinctes sont attribuées principalement à des trophismes et acidités différents. E. paludosa var. pumila, Navicula subtillissima et Asterionella ralfsii var. americana sont typiques de la tourbière de Rivière-du-Loup et reflètent des conditions ombrotrophes strictes. E. paludosa, P. aff. hilseana et P. subcapitata caractérisent la tourbière du Fleuve et suggèrent des eaux légèrement minérotrophes et moins acides. Les fluctuations négatives et positives des teneurs absolues en valves pourraient impliquer des conditions plus sèches ou plus humides strictement locales ou, peut-être, liées à des phases climatiques.In the Lower St.Lawrence, fossil diatoms from two bog cores are represented by 34 genera and 143 taxa. Both bogs have only 49 common taxa. Stratigraphie distribution of specific taxa and diatom associations permit to observe the evolution of the studied bogs. The Rivière-du-Loup Sphagnum-moss sediments contain an hydroterrestrial and acidobiont flora {Eunotia paludosa and var. pumila and E. tenella association) rather stable. In the upper 30 cm, an almost mono-species E. paludosa var. pumila flora suggest notable changes in the Sphagnum vegetation and more rigorous conditions. The diatoms from the du Fleuve Sphagnum-black spruce bog have probably evolved from stagnant, obviously minerotrophic and slightly acid waters {Cymbella aspera and Pinnularia cf. streptoraphe association) to a much more acid, oligotrophic and sub-aerial conditions (E. paludosa, Pinnularia aff. hilseana and P. subcapitata association). Distinctive floras are attributed mainly to different trophisms and acidities. E. paludosa var. pumila, Navicula subtillissima and Asterionnella ralfsii var. americana characterize the Rivière-du-Loup bog and reflect true ombrotrophic environment. E. paludosa, P. aff. hilseana and P. subcapitata are typical to the du Fleuve bog and suggest slightly minerotrophic and less acid waters. Positive and negative fluctuations of the valve numbers could imply moister or dryer conditions associated either to local environment or possibly to climatic phases.Die fossilen Diatomeen umfassen 34 Gattungen und 143 Taxa, von denen nur 49 in beiden Mooren zu finden sind. Die stratigraphische Verteilung der spezifischen Taxa und die Gesellschaften der Diatomeen ermôglichen es, die Evolution der untersuchten Moore zu beobachten. Das Sphagnum Moor von Rivière-du-Loup besitzt eine ziemlich konstante hydroterrestrische und saureliebende Flora (Assoziation mit Eunotia paludosa, E.p. var. pumila und E. tenella). Die monospezifische Gesellschaft der oberen 30 cm mit E. paludosa var. pumila Iasst einen merklichen Wechsel der Torfmoos-Vegetation und strengere Umweltbedingungen vermuten. Die Sedimente der Torfmoos-Fichten-Assoziation enthalten eine Flora, die sich wahrscheinlich aus einem stagnierenden, einwandfrei minerotrophen und leicht sauerem Milieu entwickelt hat (Gesellschaft mit Cymbella aspera und Pinnularia cf. streptoraphe), das oligotrophen, saure und sauerstoffarme Bedingunden annahm (Gesellschaft mit E. paludosa, Pinnularia aff. hilseana und P. subcapitata). Diese unterschiedlichen Floren werden hauptsâchlich verschiedenen Ernàhrungsbedingungen und Sàuregraden zugeschrieben. E. paludosa var. pumila, Navicula subtilissima und Asterionella ralfsii var. pumila sind dem Rivière-du-Loup Moor eigen und zeigen strikt ombrotrophe Bedingungen an. E. paludosa, P. aff. hilseana und P. subcapitata charakterisieren das Moor des Stroms und lassen leicht minérotrophes und schwach saures Wasser vermuten. In die negativen und positlvgn Schwankungen der absoluten Valvenzahlen kônnten trockenere oder feuchtere Bedingungen verwickelt sein, die entweder strikt an den Ort gebunden sind oder vielleicht an Klima-Phasen

A checklist for choosing between R packages in ecology and evolution

The open source and free programming language R is a phenomenal mechanism to address a multiplicity of challenges in ecology and evolution. It is also a complex ecosystem because of the diversity of solutions available to the analyst. Packages for R enhance and specialize the capacity to explore both niche data/experiments and more common needs. However, the paradox of choice or how we select between many seemingly similar options can be overwhelming and lead to different potential outcomes. There is extensive choice in ecology and evolution between packages for both fundamental statistics and for more specialized domain‐level analyses. Here, we provide a checklist to inform these decisions based on the principles of resilience, need, and integration with scientific workflows for evidence. It is important to explore choices in any analytical coding environment—not just R—for solutions to challenges in ecology and evolution, and document this process because it advances reproducible science, promotes a deeper understand of the scientific evidence, and ensures that the outcomes are correct, representative, and robust.York University Librarie

Intuition et pensée discursive : sur la fonction de l’ἐπιβολή dans les Ennéades de Plotin

L’ἐπιβολή est l’un des principaux concepts de l’épistémologie hellénistique et néoplatonicienne. Déjà associée à l’activité de la pensée (διάνοια) par Épicure et Alexandre d’Aphrodise, cette notion permet à Plotin de concevoir le passage de l’intuition, qui saisit d’un seul coup la totalité de son objet, à la pensée discursive, qui en expose successivement les multiples attributs. Elle peut être définie comme la visée d’une forme inhérente à l’âme humaine par la διάνοια, un acte intuitif qu’il revient au λόγος de traduire sous un mode propositionnel. Par analogie avec l’intuition de la pensée humaine, l’ἐπιβολή plotinienne renvoie également à la connaissance que l’Intellect a de lui-même et de son principe, l’Un-Bien.The ἐπιβολή is one of the main concepts of Hellenistic and Neoplatonic epistemology. Already related to the activity of thought (διάνοια) by Epicurus and Alexander of Aphrodisias, this notion allows Plotinus to conceive the transition from intuition, which grasps its whole object by a single act, to discursive thought, which sets out its many attributes successively. It can be defined as the sighting of an innate form by the διάνοια, an intuitive act expressed in propositional form by the λόγος. By analogy with the intuition of the human thought, the Plotinian ἐπιβολή also refers to the knowledge that the Intellect has of itself and of its principle, the One-Good

Bilan de l’intégration des services de psychiatrie dans les hôpitaux généraux. Témoignage après dix ans d’absence

L'auteur résume ici l'évolution des services psychiatriques dans la province et à Montréal jusqu'en 1977. Il décrit ensuite ce qui a été développé dans le réseau depuis cette date et de qu'il a pu observer au cours de visites effectuées dans certains centres hospitaliers de courte durée au cours de l'automne 1986, à la demande du Comité Harnois. Il a constaté, entre autres, que les projets mis de l'avant au moment des réformes Bédard et Castonguay auraient été éventuellement réalisés dans l'espoir sinon dans la lettre et que l'intégration de l'ensemble de la psychiatrie dans les C.H.C.D. était en voie d'être complétée.The author traces the evolution of psychiatrie services in Montréal and the province of Québec up until 1977. Following this summary, the author describes what has been undertaken in the area of mental health since that year. He also recounts his observations in the course of visits made in the fall of 1986 to certain hospital centers catering to short term patients (centres hospitaliers de courte durée), at the request of the Harnois Committee. Among his findings, he points out that the projects started at the onset of the Bédard and Castonguay reforms have been implemented, if not in spirit by the book, and that the integration of the entire psychiatric services of the C.H.C.D. is about to be completed