Temporal and spatial variation in the morphology of the brown macroalga Hormosira banksii (Fucales, Phaeophyta)

Hormosira banksii is a morphologically variable macroalgal species from southeastern and southern Australia, which has been previously categorised into ecoforms according to habitat. This study is by far the largest quantitative evaluation of morphological variation in H. banksii, covering 74 sites from South Australia, Victoria, New South Wales and Tasmania. Morphological features from 505 samples were analysed using principal components analysis, with the patterns identified being statistically assessed with a Monte Carlo permutation test. There was considerable morphological variation between samples taken at several marine (but not estuarine) sites in both 1994 and 1999. However, this variation was not consistent across either morphological features or populations, and presumably represents random fluctuations. Analysis of the entire dataset demonstrated a significant difference between samples growing in marine and estuarine habitats. Further assessment of variation within these two groups revealed some significantly different populations based on geographical locations but not habitat variation. While this study presents strong evidence for two distinct taxa within H. banksii (marine versus estuarine populations), the taxonomic status of this species should not be altered until genetic studies have been conducted. © 2005 by Walter de Gruyter

Mapping 6D N = 1 supergravities to F-theory

We develop a systematic framework for realizing general anomaly-free chiral 6D supergravity theories in F-theory. We focus on 6D (1, 0) models with one tensor multiplet whose gauge group is a product of simple factors (modulo a finite abelian group) with matter in arbitrary representations. Such theories can be decomposed into blocks associated with the simple factors in the gauge group; each block depends only on the group factor and the matter charged under it. All 6D chiral supergravity models can be constructed by gluing such blocks together in accordance with constraints from anomalies. Associating a geometric structure to each block gives a dictionary for translating a supergravity model into a set of topological data for an F-theory construction. We construct the dictionary of F-theory divisors explicitly for some simple gauge group factors and associated matter representations. Using these building blocks we analyze a variety of models. We identify some 6D supergravity models which do not map to integral F-theory divisors, possibly indicating quantum inconsistency of these 6D theories.Comment: 37 pages, no figures; v2: references added, minor typos corrected; v3: minor corrections to DOF counting in section

Neural crest migration is driven by a few trailblazer cells with a unique molecular signature narrowly confined to the invasive front

Neural crest (NC) cell migration is crucial to the formation of peripheral tissues during vertebrate development. However, how NC cells respond to different microenvironments to maintain persistence of direction and cohesion in multicellular streams remains unclear. To address this, we profiled eight subregions of a typical cranial NC cell migratory stream. Hierarchical clustering showed significant differences in the expression profiles of the lead three subregions compared with newly emerged cells. Multiplexed imaging of mRNA expression using fluorescent hybridization chain reaction (HCR) quantitatively confirmed the expression profiles of lead cells. Computational modeling predicted that a small fraction of lead cells that detect directional information is optimal for successful stream migration. Single-cell profiling then revealed a unique molecular signature that is consistent and stable over time in a subset of lead cells within the most advanced portion of the migratory front, which we term trailblazers. Model simulations that forced a lead cell behavior in the trailing subpopulation predicted cell bunching near the migratory domain entrance. Misexpression of the trailblazer molecular signature by perturbation of two upstream transcription factors agreed with the in silico prediction and showed alterations to NC cell migration distance and stream shape. These data are the first to characterize the molecular diversity within an NC cell migratory stream and offer insights into how molecular patterns are transduced into cell behaviors

CHEMICAL SIGNATURE OF GROUNDWATER IN COVER OVERLYING DULUTH COMPLEX NI-CU-PGE DEPOSITS, NE MINNESOTA

The U.S. Geological Survey initiated a project in 2015 aimed at evaluating geochemical exploration methods for covered deposits in the northern Midcontintent Rift, employing both site-scale studies and regional geochemical databases. A first group of groundwater samples was collected from unconsolidated material overlying the Spruce Road, Wyman Creek, and Skibo deposits in the Duluth Complex to determine effective sampling methods, characterize the groundwater chemical signature of these deposits, and determine chemical evolution along flow paths. Twenty-seven samples were collected from mini-piezometers at depths <5 m and analyzed for major and trace element chemistry and stable isotopes of water. Ten samples were also analyzed for groundwater age tracers, including noble gases, 3H, He isotopes, and chlorofluorocarbons. Site conditions presented challenges for deriving well-constrained specific ages. However, samples could be sorted into the following age categories by employing multiple tracers: <0.5 yr; 0.5 to 2 yr; 2 to 10 yr; and 15 to 30 yr. Cu and Ni concentrations over the deposits range from <0.5 to 150 μg/L and from <1 to 348 μg/L, respectively, and are commonly elevated above background. Cu and Ni are negatively correlated with pH (range of 5.7 to 8.6), probably due to progressively more adsorption on negatively charged mineral surfaces at higher pH. The pH also increases with groundwater age, likely due to weathering of abundant mafic minerals. As a result, Cu and Ni concentrations generally decrease with increasing age. These results suggest that pH provides an important limit on Cu and Ni mobility in the groundwater system, which must be taken into account in designing geochemical exploration approaches. In addition to site-scale work, a regional groundwater chemical database was compiled from available USGS (NWIS) and state databases. Initial examination reveals both geogenic and anthropogenic metal anomalies, and spatial analyses are ongoing

Centriole splitting caused by loss of the centrosomal linker protein C-NAP1 reduces centriolar satellite density and impedes centrosome amplification

Duplication of the centrosomes is a tightly regulated process. Abnormal centrosome numbers can impair cell division and cause changes in how cells migrate. Duplicated centrosomes are held together by a proteinaceous linker made up of rootletin filaments anchored to the centrioles by C-NAP1. This linker is removed in a NEK2A kinase-dependent manner as mitosis begins. To explore C-NAP1 activities in regulating centrosome activities, we used genome editing to ablate it. C-NAP1–null cells were viable and had an increased frequency of premature centriole separation, accompanied by reduced density of the centriolar satellites, with reexpression of C-NAP1 rescuing both phenotypes. We found that the primary cilium, a signaling structure that arises from the mother centriole docked to the cell membrane, was intact in the absence of C-NAP1, although components of the ciliary rootlet were aberrantly localized away from the base of the cilium. C-NAP1–deficient cells were capable of signaling through the cilium, as determined by gene expression analysis after fluid flow–induced shear stress and the relocalization of components of the Hedgehog pathway. Centrosome amplification induced by DNA damage or by PLK4 or CDK2 overexpression was markedly reduced in the absence of C-NAP1. We conclude that centriole splitting reduces the local density of key centriolar precursors to impede overduplication

An investigation of supervector regression for forensic voice comparison on small data

International audienceThe present paper deals with an observer design for a nonlinear lateral vehicle model. The nonlinear model is represented by an exact Takagi-Sugeno (TS) model via the sector nonlinearity transformation. A proportional multiple integral observer (PMIO) based on the TS model is designed to estimate simultaneously the state vector and the unknown input (road curvature). The convergence conditions of the estimation error are expressed under LMI formulation using the Lyapunov theory which guaranties bounded error. Simulations are carried out and experimental results are provided to illustrate the proposed observer

Experience with UIDC insertion outside of menses in Kenya

Objective: To determine if women receiving intrauterine devices (IUCDs) outside of menses have an acceptable rate of insertion problems and subsequent IUCD-related complications.Design: Cross-sectional and prospective cohort study of insertions at times other than during menses.Setting: The study was carried out in two government family planning (FP) clinics in Nairobi,Kenya.Subjects: After appropriate pre-test and post-test HIV counselling, 1686 women requesting IUCDs at two FP clinics between 1994 and 1995 in Nairobi were enrolled at baseline into a study examining the effect of human complications. Six hundred and forty nine women (156 HIV-infected and 493 HIVuninfected) were selected for the four month follow up study. They were classified according to their menstrual cycle status at time of IUCD insertion.Main outcome measures: Problems at the time of insertion (pain, bleeding, immediate expulsion) and IUCD-related complications through four months.Results: Rates of immediate insertion problems were low in the women who had insertions during menses (7.0%), outside of menses (4.0%) or had oligomenorrhea/amenorrhea (2.6%). The adjusted odds ratios for IUCD insertion problems outside of menses and in oligomenorrhea/amenorrhea (versus women with insertion during menses) were 0.54 (95% CI 0.18 -1.59) and 0.39 (95% CI 0.12 -1.29) respectively. IUCD-related complications were higher in the iligomenorrhea/amenorrhea (11.5%) or insertion outside of menses (6.9%), than the within menses (4.3%) groups. However, the differences were not statistically significant. Adjusted odds ratios for IUCD outside of menses and oligomenorrhoea/amenorrhea groups were 1.65 (95% CI 0.21 - 12.91) and 2.72 (95% CI 0.34 - 21.71) respectively.Conclusion: The results confirm that the IUCD can be safely inserted outside of menses with minimal insertion difficulties and subsequent complications. Availability of IUCDs outside of menses may enhance IUCD acceptance in Kenya and create better opportunity for visualscreening of the cervix for sexually transmitted infections

Biological Control of Sheep Parasites using Duddingtonia flagrans: Trials on Commercial Farms in Sweden

Trials were conducted on 3 commercial sheep farms in Sweden to assess the effect of administering spores of the nematode trapping fungus, Duddingtonia flagrans, together with supplementary feed to lactating ewes for the first 6 weeks from turn-out on pastures in spring. Also control groups of ewes, receiving only feed supplement, were established on all 3 farms. Groups were monitored by intensive parasitological investigation. The ewes and their lambs were moved in late June to saved pastures for summer grazing, the lambs receiving an anthelmintic treatment at this time. After approximately 6 weeks on summer pasture the lambs were weaned, treated a second time with anthelmintic, and returned to their original lambing pastures for finishing. Decisions as to when lambs were to be marketed were entirely at the discretion of the farmer co-operators. No difference in lamb performance was found between the two treatments on all three farms. This was attributed to the high levels of nutrition initially of the ewes limiting their post-partum rise in nematode faecal egg counts in spring, which in turn resulted in low levels of nematode infection on pastures throughout the autumn period. Additionally, pastures were of good quality for the lambs during the finishing period, so they grew at optimal rates as far as the farmers were concerned

Del Pezzo surfaces with 1/3(1,1) points

We classify del Pezzo surfaces with 1/3(1,1) points in 29 qG-deformation families grouped into six unprojection cascades (this overlaps with work of Fujita and Yasutake), we tabulate their biregular invariants, we give good model constructions for surfaces in all families as degeneracy loci in rep quotient varieties and we prove that precisely 26 families admit qG-degenerations to toric surfaces. This work is part of a program to study mirror symmetry for orbifold del Pezzo surfaces.Comment: 42 pages. v2: model construction added of last remaining surface, minor corrections, minor changes to presentation, references adde