Flow Regime: Habitat and Macroinvertebrate Response

Rivers are complex linear features, (Petts, 1994). Assessing habitat quality and composition has traditionally focused on reaches of 10s metres, recently interest has moved to the mesoscale (100s of metres) e.g. Paraseiwicz (2001); Maddock and Bird (1996). Assessment at the catchment scale is the ultimate goal, e.g. European Water Framework Directive (Bragg et al, 2005) and will possibly require an element of remote sensing to be effective. In field trials, inter-operator variability of four meso-scale habitat mapping methods: MesoCaSiMiR, MesoHABSIM, Norwegian Mesohabitat Classification Method and Rapid Habitat Mapping was found to be up to 85% by area surveyed (Maddock and Hill, 2005). Further, the biological relevance of some methods, such as the weighted usable area output from PHABSIM/MesoHABSIM, has been challenged by some (Thoms, 2006) and others, whilst habitat connectivity is increasingly important (Walker, 2006)

The Effect of Flow Regulation on Channel Geomorphic Unit (CGU) Composition in the Soča River, Slovenia.

This paper sets out to examine the effects of flow regulation on the size, spatial distribution and connectivity of physical habitats or channel geomorphic units (CGU) of an upland river system in Slovenia. A river channel survey was completed along three reaches (totalling 14.3km) of the Soča River in order compare an unregulated stretch (reach 1), with two regulated reaches with lower discharges, i.e. a bypassed section that experiences significant flow reduction (reach 2), and a stretch regulated by dam operation (reach 3). CGU’s were classified according to a modified version of the Hawkins et al (1993) system, and mapped on foot and from a boat using a combination of visual assessment and physical measurement. Mapping-grade GPS was used to locate CGU boundaries to sub-metre accuracy, and the application of GIS (MapInfo) enabled the description and analysis of the longitudinal distribution of CGU’s along each reach. Results demonstrated significant differences in the CGU composition between the unregulated and regulated reaches. The unregulated stretch (reach 1) was dominated by the glides (55%) with relatively fast-flowing and turbulent features (runs, riffles and rapids) making up the rest of the reach. The dominant feature of both of the regulated reaches were the slow flowing pool CGU’s occupying 44% of the bypassed section (reach 2), and 76% of the dam regulated section (reach 3), with glides, runs, riffles and rapids forming the remainder of the CGU’s. Physical measurements highlighted the extent to which the reduced discharge in the regulated reaches was dewatering the channel and reducing the size of the CGU’s. The average CGU size in the unregulated stretch (reach 1) was 58m2 of water area per m of channel length (m2/m) compared to 18.42m2/m in the reach 2, and 29.22m2/m in reach 3. CGU’s tended to be shorter, and hence there was greater habitat division or fragmenta-tion evident in the two regulated reaches, particularly the bypassed section. For example, there were on aver-age 6.81 CGU’s per km in the unregulated reach (reach 1), 18.12 CGU/km in reach 2, and 8.08 CGU/km in reach 3. This study suggests that in the Soča River under the flow conditions present during the survey, flow regula-tion alters the dominant types of CGU’s present (to slower flowing and less turbulent features), significantly reduces the size of CGU’s, and affects the longitudinal distribution of types by reducing habitat connectivity and creating greater habitat fragmentation

River Habitat Mapping: are Surface Flow Type Habitats Biologically Distinct?

Current river habitat mapping uses several methods, many relying on descriptions of habitat units based on depth, velocity, substrate and water surface patterns. Water surface patterns are controlled by local geomorphology and hydraulics and can be remotely sensed, if surface flow type habitats are physically and biologically distinctive this may provide a faster surveying method. Six UK lowland rivers were investigated, surface flow types were mapped and the physical characteristics of each habitat unit recorded. Samples of benthic macroinvertebrates were taken from representative units and quantified. The results show that habitat mapping, using surface flow types in small lowland streams, is viable and that those habitats have some degree of physical distinctiveness. Analysis of benthic macroinvertebrate communities shows that there is some association with mapped habitats, and therefore are potentially biologically relevant

An ultra-weak sector, the strong CP problem and the pseudo-Goldstone dilaton

In the context of a Coleman-Weinberg mechanism for the Higgs boson mass, we address the strong CP problem. We show that a DFSZ-like invisible axion model with a gauge-singlet complex scalar field S, whose couplings to the Standard Model are naturally ultra-weak, can solve the strong CP problem and simultaneously generate acceptable electroweak symmetry breaking. The ultra-weak couplings of the singlet S are associated with underlying approximate shift symmetries that act as custodial symmetries and maintain technical naturalness. The model also contains a very light pseudo-Goldstone dilaton that is consistent with cosmological Polonyi bounds, and the axion can be the dark matter of the universe. We further outline how a SUSY version of this model, which may be required in the context of Grand Unification, can avoid introducing a hierarchy problem.Comment: 9 page

Ultra-weak sector, Higgs boson mass, and the dilaton

The Higgs boson mass may arise from a portal coupling to a singlet field $\sigma$ which has a very large VEV $f \gg m_\text{Higgs}$. This requires a sector of "ultra-weak" couplings $\zeta_i$, where $\zeta_i \lesssim m_\text{Higgs}^2 / f^2$. Ultra-weak couplings are technically naturally small due to a custodial shift symmetry of $\sigma$ in the $\zeta_i \rightarrow 0$ limit. The singlet field $\sigma$ has properties similar to a pseudo-dilaton. We engineer explicit breaking of scale invariance in the ultra-weak sector via a Coleman-Weinberg potential, which requires hierarchies amongst the ultra-weak couplings.Comment: 6 page

The cationic region of Rhes mediates its interactions with specific Gβ subunits

Ras homologue enriched in striatum (Rhes) is a small monomeric G protein which functions in a variety of cellular processes, including attenuation of G protein-coupled receptor (GPCR)signalling. There have been many studies into the effects of Rhes, but there is no molecular information about how Rhes might bring about these effects. Rhes shares striking sequence homology to AGS1 (activator of G protein signalling 1) and we considered whether the two proteins function in similar ways. AGS1 binds to the Gβ1 subunit of heterotrimeric G proteins and we have used yeast two-hybrid studies to show that Rhes binds selectively to Gβ1, Gβ2 and Gβ3 subunits. Binding to the Gβ subunits involves the cationic regions of AGS1 and Rhes, and we used Rhes-AGS1 chimeras to show that their different cationic regions determine the Gβ-specificity of the interactions. Possible implications of this interaction for the activity of Rhes are discussed

The sedimentology and lithostratigraphy of the Upper Jurassic Lourinha formation, Lusitanian Basin, Portugal

The Lusitanian Basin of West-Central Portugal is one of a family of formerly adjacent North Atlantic margin basins. Like others of its type (e.g. the Jeanne d'Arcand Western Approaches basins) early phases of rifting and subsidence occurred as far back as the Triassic.During the Late Jurassic rifting phase in the development of the Lusitanian Basin marine shelf and slope systems were replaced by alluvial fan and fluvial environments which prograded from the nonh during the late Kimmeridgian. Continental environments, periodically punctuated by marine incursions, persisted over northern and central areas of the basin at least until the end of the Jurassic. The deposits of these continental and shallow marine systems are here defined as the Lourinha formation, which is sub-divided into five members.Sedimentary structures, textures and sand body geometries suggest that the Praia da Amoreira member was deposited in a distal alluvial fan setting where sheet-flooding preceded the establishment of channelised flow. The presence of calcretes suggests a semi-arid/sub-tropical climate with markedly seasonal rainfall. The fan systems,confined to the western margin of the basin, passed laterally into meandering fluvial systems, the deposits of which form the Porto Novo member.A marine transgression from the south resulted in the establishment of shoal-water delta systems, the deposits of which form the Praia Azul (lower delta plain) and Assenta (upper delta/fluvial plain) members. The largely continental Assenta member is punctuated by thin, laterally extensive marine horizons which suggest rapid relative rises in sea level. In northem and eastern parts of the basin the deposits of sandy fluvial systems are replaced by those of the gravelly Santa Rita member, which appear to have been sourced from the east.In a number of the above units evidence for the operation of active extensional processes is to be found The deposition of the Lourinha formation preceded the final Aptian rifting event which resulted in the formation of the North Atlantic Ocean. However, it may have heralded and been contemporaneous with, an earlier phase of sea floor spreading, later abandoned, thought to have occurred In the area of the present day Tagus Abyssal Plain

Inertial Spontaneous Symmetry Breaking and Quantum Scale Invariance

Weyl invariant theories of scalars and gravity can generate all mass scales spontaneously, initiated by a dynamical process of "inertial spontaneous symmetry breaking" that does not involve a potential. This is dictated by the structure of the Weyl current, $K_\mu$, and a cosmological phase during which the universe expands and the Einstein-Hilbert effective action is formed. Maintaining exact Weyl invariance in the renormalised quantum theory is straightforward when renormalisation conditions are referred back to the VEV's of fields in the action of the theory, which implies a conserved Weyl current. We do not require scale invariant regulators. We illustrate the computation of a Weyl invariant Coleman-Weinberg potential

The Effect of Flow Regulation on the Spatial Distribution and Dynamics of Channel Geomorphic Units (CGU’s) in the Soča River, Slovenia.

This research examines the impact of flow regulation on the spatial distribution and dynamics of physical habitats or channel geomorphic units (CGU) of the Soca River, an upland river system in Slovenia. In order to assess the impact of flow alteration on the spatial pattern of CGU type, size, hydraulics and distribution, a river channel survey was completed along three reaches (totalling 14.3km), i.e. an unregulated stretch and two regulated reaches (with reduced flows). In addition, one regulated reach was re-surveyed at different discharges to investigate the dynamics of CGU’s and their relationship with flow. CGU’s were classified and mapped on foot and from a boat using a combination of visual assessment and physical measurements of velocity and depth in each CGU. Mapping-grade GPS was used to locate CGU boundaries to sub-metre accuracy, and the application of GIS (MapInfo) enabled the description and analysis of the longitudinal distribution of CGU’s along each reach. The effect of flow regulation on the hydraulic character of the river becomes apparent by highlighting significant differences in the dominant types of CGU’s present between the regulated and unregulated reaches. Reduced flows from river regulation also significantly reduces the size of CGU’s, alters their hydraulic character, and affects the longitudinal distribution of types by creating greater habitat fragmentation. This work also highlights the need to assess CGU’s along continuous stretches of river in order to understand the nature and dynamics of river habitats