Traitement tertiaire d'eaux usées municipales par culture de Scenedesmus sp. en installation pilote

Deux installations pilote destinées au traitement d'effluents secondaires par culture de micro-algues (Scenedesmus sp.) ont été opérées à Valcartier (effluents domestiques) et Vaudreuil (effluents semi-industriels). Des bassins de 15 000 L ont servi aux cultures en vrac sous conditions naturelles, avec apport de CO2 atmosphérique par huilage. Les paramètres physiques, chimiques et biologiques ont été mesurés.Les résultats montrent que, malgré les limitations en CO2 et en azote, un enlèvement moyen d'environ 95 % pour l'azote (N-NH4+, N-NO2-, N-NO3-) et de 60 % pour le phosphore (P-PO4-3) a été possible à Valcartier durant l'été; les données correspondantes sont de 92 % et de 98 % à Vaudreuil où la production de biomasse (1,02 mg/L-h) a été plus forte qu'à Valcartier (0,39 mg/L-h). Les facteurs pouvant expliquer les différences observées aux deux sites sont présentées. Les résultats montrent la faisabilité technique, durant l'été, de ce type de traitement tertiaire.Two experimental pilot-scale culture systems have been operated at Valcartier (domestic effluent) and Vaudreuil (semi-industrial urban effluent) in order to test the feasibility of a tertiary treatment using microalgae (Scenedesmus sp.). Tanks with a capacity of 15 000 L were used for batch cultures conducted outdoors; CO2 being provided through atmospheric air bubbling. Physical (temperature, relative insolation, solar radiation), chemical (pH, NH4+, NO2-, NO3-, PO4-3, heavy metal, pesticides) and biological parameters (biomass dry weight, cell counts) were mesured.Results show that cultures were limited for CO2 (high final pH) and for nitrogen flow N/P ratio with value of 3-7). During the summer period, nutrient removal from the Valcartier effluent was ~ 95 % for N and ~ 60 % for P; corresponding figures at Vaudreuil were 92 % and 98 %.Biomass productivity was lower (0,39 mg/L-h) at Valcartier compared to that obtained at Vaudreuil (1,02 mg/L-h). Among the differences that could explain the results at both sites, one may suggest a better CO2 input, a more favorable N/P ratio, slightly higher average temperature and light conditions, less ammonia stripping and larger inocula in Vaudreuil. The quality of biomass obtained was satisfactory : heavy metals were present at acceptable levels and no contamination by organochlorinated compounds occurred. According to our results, it appears that biological tertiary treatment of urban effluent and algal biomass production are technically possible under Québec summer conditions

Duality between simple-group gauge theories and some applications

In this paper we investigate N=1 supersymmetric gauge theories with a product gauge group. By using smoothly confining dynamics, we can find new dualities which include higher-rank tensor fields, and in which the dual gauge group is simple, not a product. Some of them are dualities between chiral and non-chiral gauge theories. We also discuss some applications to dynamical supersymmetry breaking phenomena and new confining theories with a tree-level superpotential.Comment: 33 pages, LaTeX, references added, version to appear in PR

Conformal Gauge Mediation and Light Gravitino of Mass m_{3/2} <O(10) eV

We discuss a class of gauge mediated supersymmetry breaking models with conformal invariance above the messenger mass scale (conformal gauge mediation). The spectrum of the supersymmetric particles including the gravitino is uniquely determined by the messenger mass. When the conformal fixed point is strongly interacting, it predicts a light gravitino of mass m_{3/2}<O(10) eV, which is attractive since such a light gravitino causes no problem in cosmology.Comment: 14 page

Conformal Gauge Mediation

We propose a one-parameter theory for gauge mediation of supersymmetry (SUSY) breaking. The spectrum of SUSY particles such as squarks and sleptons in the SUSY standard-model and the dynamics of SUSY-breaking sector are, in principle, determined only by one parameter in the theory, that is, the mass of messengers. Above the messenger threshold all gauge coupling and Yukawa coupling constants in the SUSY-breaking sector are on the infrared fixed point. We find that the present theory may predict a split spectrum of the standard-model SUSY particles, m_{gaugino} < m_{sfermion}, where m_{gaugino} and m_{sfermion} are SUSY-breaking masses for gauginos and squarks/sleptons, respectively.Comment: 17 page

A Geometry of the Generations

We propose a geometric theory of flavor based on the discrete group $(S_3)^3$, in the context of the minimal supersymmetric standard model. The group treats three objects symmetrically, while making fundamental distinctions between the generations. The top quark is the only heavy quark in the symmetry limit, and the first and second generation squarks are degenerate. The hierarchical nature of Yukawa matrices is a consequence of a sequential breaking of $(S_3)^3$.Comment: 10 pages, 1 EPS figure as uuencoded tar-compressed file, uses psfig.st

Persistence of balsam fir and black spruce populations in the mixedwood and coniferous bioclimatic domain of eastern North America

The boreal ecocline (ca 49°N) between the southern mixedwood (dominated by balsam fir) and the northern coniferous bioclimatic domain (dominated by black spruce) may be explained by a northward decrease of balsam fir regeneration, explaining the gradual shift to black spruce dominance. 7,010 sample plots, with absence of major disturbances, were provided by the Quebec Ministry of Forest, Fauna, and Parks. The regeneration (sapling abundance) of balsam fir and black spruce were compared within and between the two bioclimatic domains, accounting for parental trees, main soil type (clay and till) and climate conditions, reflected by summer growing degree-days above 5°C (GDD_5), total summer precipitation (May–August; PP_MA). Parental trees and soil type determined balsam fir and black spruce regeneration. Balsam fir and black spruce, respectively, showed higher regeneration in the mixedwood and the coniferous bioclimatic domains. Overall, higher regeneration was obtained on till for balsam fir, and on clay soils for black spruce. GDD_5 and PP_MA were beneficial for balsam fir regeneration on clay and till soils, respectively, while they were detrimental for black spruce regeneration. At a population level, balsam fir required at least 28% of parental tree basal area in the mixedwood, and 38% in the coniferous bioclimatic domains to maintain a regeneration at least equal to the mean regeneration of the whole study area. However, black spruce required 82% and 79% of parental trees basal area in the mixedwood and the coniferous domains, respectively. The northern limit of the mixedwood bioclimatic domain was attributed to a gradual decrease toward the north of balsam fir regeneration most likely due to cooler temperatures, shorter growing seasons, and decrease of the parental trees further north of this northern limit. However, balsam fir still persists above this northern limit, owing to a patchy occurrence of small parental trees populations, and good establishment substrates

Moduli in Exceptional SUSY Gauge Theories

The low energy structures of N=1 supersymmetric models with E_6, F_4 and E_7 gauge groups and fundamental irrep matter contents are studied herein. We identify sets of gauge invariant composites which label all flat directions in the confining/Higgs phases of these theories. The impossibility of mapping several of these primary operators rules out previously conjectured exceptional self duals reported in the literature.Comment: 20 pages, harvmac and tables macro

Democratic (S)fermions and Lepton Flavor Violation

The democratic approach to account for fermion masses and mixing is known to be successful not only in the quark sector but also in the lepton sector. Here we extend this ansatz to supersymmetric standard models, in which the K\"ahler potential obeys underlying S_3 flavor symmetries. The requirement of neutrino bi-large mixing angles constrains the form of the K\"ahler potential for left-handed lepton multiplets. We find that right-handed sleptons can have non-degenerate masses and flavor mixing, while left-handed sleptons are argued to have universal and hence flavor-blind masses. This mass pattern is testable in future collider experiments when superparticle masses will be measured precisely. Lepton flavor violation arises in this scenario. In particular, \mu \to e \gamma is expected to be observed in a planning future experiment if supersymmetry breaking scale is close to the weak scale.Comment: 22 pages, 2 figure

Flavor Alignment Solutions to the Strong CP Problem in Supersymmetry

An approach to solving the Strong CP Problem in supersymmetric theories is discussed which uses abelian family symmetries to align the mass matrices of the quarks and squarks. In this way both the Strong CP Problem and the characteristic flavor and CP problems of supersymmetry can be solved in a single way.Comment: 13 pages, LaTe