Three Different Types of Galaxy Alignment within Dark Matter Halos

Using a large galaxy group catalogue based on the Sloan Digital Sky Survey Data Release 4 we measure three different types of intrinsic galaxy alignment within groups: halo alignment between the orientation of the brightest group galaxies (BGG) and the distribution of its satellite galaxies, radial alignment between the orientation of a satellite galaxy and the direction towards its BGG, and direct alignment between the orientation of the BGG and that of its satellites. In agreement with previous studies we find that satellite galaxies are preferentially located along the major axis. In addition, on scales r < 0.7 Rvir we find that red satellites are preferentially aligned radially with the direction to the BGG. The orientations of blue satellites, however, are perfectly consistent with being isotropic. Finally, on scales r < 0.1 \Rvir, we find a weak but significant indication for direct alignment between satellites and BGGs. We briefly discuss the implications for weak lensing measurements.Comment: 4 pages, 4 figures, ApJL accepte

New observations on test architecture and construction of Jullienella foetida Schlumberger, 1890, the largest shallow-water agglutinated foraminifer in modern oceans

We present new observations on Jullienella foetida Schlumberger, 1890, a giant agglutinated foraminifer with a leaf- or fan-like test reaching a maximum dimension of 14 cm, that is common on some parts of the west African continental shelf. The test wall comprises a smooth, outer veneer of small (7.0 g wet weight m−2 for the seafloor biomass of J. foetida in areas where it is particularly abundant. The relatively restricted distribution of this species off the north-west African coast at depths above 100 m is probably related to the elevated, upwelling-related surface productivity along this margin, which provides enough food to sustain this high biomass. This remarkable species appears to play an important, perhaps keystone, role in benthic ecosystems where it is abundant, providing the only common hard substrate on which sessile organisms can settle

Intranasal delivery of full-length anti-Nogo-A antibody: A potential alternative route for therapeutic antibodies to central nervous system targets

Antibody delivery to the CNS remains a huge hurdle for the clinical application of antibodies targeting a CNS antigen. The blood-brain barrier and blood-CSF barrier restrict access of therapeutic antibodies to their CNS targets in a major way. The very high amounts of therapeutic antibodies that are administered systemically in recent clinical trials to reach CNS targets are barely viable cost-wise for broad, routine applications. Though global CNS delivery of antibodies can be achieved by intrathecal application, these procedures are invasive. A non-invasive method to bring antibodies into the CNS reliably and reproducibly remains an important unmet need in neurology. In the present study, we show that intranasal application of a mouse monoclonal antibody against the neurite growth-inhibiting and plasticity-restricting membrane protein Nogo-A leads to a rapid transfer of significant amounts of antibody to the brain and spinal cord in intact adult rats. Daily intranasal application for 2 wk of anti-Nogo-A antibody enhanced growth and compensatory sprouting of corticofugal projections and functional recovery in rats after large unilateral cortical strokes. These findings are a starting point for clinical translation for a less invasive route of application of therapeutic antibodies to CNS targets for many neurological indications

The STAGES view of red spirals and dusty red galaxies: Mass-dependent quenching of star-formation in cluster infall

We investigate the properties of optically passive spirals and dusty red galaxies in the A901/2 cluster complex at redshift ~0.17 using restframe near-UV-optical SEDs, 24 micron IR data and HST morphologies from the STAGES dataset. The cluster sample is based on COMBO-17 redshifts with an rms precision of sigma_cz~2000 km/sec. We find that 'dusty red galaxies' and 'optically passive spirals' in A901/2 are largely the same phenomenon, and that they form stars at a substantial rate, which is only 4x lower than that in blue spirals at fixed mass. This star formation is more obscured than in blue galaxies and its optical signatures are weak. They appear predominantly in the stellar mass range of log M*/Msol=[10,11] where they constitute over half of the star-forming galaxies in the cluster; they are thus a vital ingredient for understanding the overall picture of star formation quenching in clusters. We find that the mean specific SFR of star-forming galaxies in the cluster is clearly lower than in the field, in contrast to the specific SFR properties of blue galaxies alone, which appear similar in cluster and field. Such a rich red spiral population is best explained if quenching is a slow process and morphological transformation is delayed even more. At log M*/Msol<10, such galaxies are rare, suggesting that their quenching is fast and accompanied by morphological change. We note, that edge-on spirals play a minor role; despite being dust-reddened they form only a small fraction of spirals independent of environment.Comment: Accepted for publication in MNRA

Measures of Galaxy Environment - I. What is "Environment"?

The influence of a galaxy's environment on its evolution has been studied and compared extensively in the literature, although differing techniques are often used to define environment. Most methods fall into two broad groups: those that use nearest neighbours to probe the underlying density field and those that use fixed apertures. The differences between the two inhibit a clean comparison between analyses and leave open the possibility that, even with the same data, different properties are actually being measured. In this work we apply twenty published environment definitions to a common mock galaxy catalogue constrained to look like the local Universe. We find that nearest neighbour-based measures best probe the internal densities of high-mass haloes, while at low masses the inter-halo separation dominates and acts to smooth out local density variations. The resulting correlation also shows that nearest neighbour galaxy environment is largely independent of dark matter halo mass. Conversely, aperture-based methods that probe super-halo scales accurately identify high-density regions corresponding to high mass haloes. Both methods show how galaxies in dense environments tend to be redder, with the exception of the largest apertures, but these are the strongest at recovering the background dark matter environment. We also warn against using photometric redshifts to define environment in all but the densest regions. When considering environment there are two regimes: the 'local environment' internal to a halo best measured with nearest neighbour and 'large-scale environment' external to a halo best measured with apertures. This leads to the conclusion that there is no universal environment measure and the most suitable method depends on the scale being probed.Comment: 14 pages, 9 figures, 1 table, published in MNRA

Climate-driven range extension of Amphistegina (protista, foraminiferida) : models of current and predicted future ranges

© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS ONE 8 (2013): e54443, doi:10.1371/journal.pone.0054443.Species-range expansions are a predicted and realized consequence of global climate change. Climate warming and the poleward widening of the tropical belt have induced range shifts in a variety of marine and terrestrial species. Range expansions may have broad implications on native biota and ecosystem functioning as shifting species may perturb recipient communities. Larger symbiont-bearing foraminifera constitute ubiquitous and prominent components of shallow water ecosystems, and range shifts of these important protists are likely to trigger changes in ecosystem functioning. We have used historical and newly acquired occurrence records to compute current range shifts of Amphistegina spp., a larger symbiont-bearing foraminifera, along the eastern coastline of Africa and compare them to analogous range shifts currently observed in the Mediterranean Sea. The study provides new evidence that amphisteginid foraminifera are rapidly progressing southwestward, closely approaching Port Edward (South Africa) at 31°S. To project future species distributions, we applied a species distribution model (SDM) based on ecological niche constraints of current distribution ranges. Our model indicates that further warming is likely to cause a continued range extension, and predicts dispersal along nearly the entire southeastern coast of Africa. The average rates of amphisteginid range shift were computed between 8 and 2.7 km year−1, and are projected to lead to a total southward range expansion of 267 km, or 2.4° latitude, in the year 2100. Our results corroborate findings from the fossil record that some larger symbiont-bearing foraminifera cope well with rising water temperatures and are beneficiaries of global climate change.This work was supported by grants from the German Science Foundation (DFG; www.dfg.de) to ML and SL (LA 884/10-1, LA 884/5-1)

Effects of sampling site, season, and substrate on foraminiferal assemblages grown from propagule banks from lagoon sediments of Corfu Island (Greece, Ionian Sea).

Foraminiferal propagule banks occur in fine sediment fractions that contain small individuals of benthic foraminifera. These sediments include locally sourced juveniles and propagules, as well as allochthonous propagules that have dispersed from surrounding areas. Such propagules can remain viable even under unfavorable local conditions. When exposed to more favorable conditions, they may grow to adult stages. Accordingly, during environmental changes, propagule banks have the potential to function as species pools and allow quick assemblage reactions. The propagule method was designed to study responses of foraminiferal assemblages by exposing propagule banks to controlled conditions in the laboratory, an approach that is applicable to a variety of ecological questions. Therefore it is important to understand the nature and dynamics of propagule banks, including local and seasonal influences. To obtain insights into the composition of local propagule banks, we studied experimentally grown assemblages from two shallow-water lagoons on Corfu Island in western Greece, and compared the results with in situ assemblages. We sampled in spring and autumn of 2017 and experimental treatments included the use of different substrates in our experiments to account for potential effects on assemblage compositions. Results revealed that sediments from each lagoon contained a distinct propagule bank. We found abundant allochthonous taxa among specimens grown in all experimental treatments, indicating dispersal of propagules, and possibly also juveniles, from adjacent regions into both lagoons. The time of sampling had a significant effect on experimental assemblages, indicating that the composition of propagule banks can vary throughout the year. However, no significant differences were found in assemblages grown in different substrata, suggesting a stronger influence of water variables (e.g., temperature or salinity) on assemblage compositions. Moreover, the experimental set-ups favored small, fast-growing, sediment-dwelling species tolerant of relatively high organic content. Our findings highlight the potential of propagule banks as species pools and will help to refine and improve future applications of the method

Heading for New Shores: Projecting Marine Distribution Ranges of Selected Larger Foraminifera

<div><p>The distribution of modern symbiont-bearing larger foraminifera is confined to tropical and subtropical shallow water marine habitats and a narrow range of environmental variables (e.g. temperature). Most of today's taxa are restricted to tropical and subtropical regions (between 30°N and 30°S) and their minimum temperature limits are governed by the 14 to 20°C isotherms. However, during times of extensive global warming (e.g., the Eocene and Miocene), larger foraminifera have been found as far north as 50°N (North America and Central Europe) as well as towards 47°S in New Zealand. During the last century, sea surface temperatures have been rising significantly. This trend is expected to continue and climate change scenarios for 2050 suggest a further increase by 1 to 3°C. We applied Species Distribution Models to assess potential distribution range changes of three taxa of larger foraminifera under current and future climate. The studied foraminifera include <i>Archaias angulatus</i>, <i>Calcarina</i> spp., and <i>Amphistegina</i> spp., and represent taxa with regional, superregional and global distribution patterns. Under present environmental conditions, <i>Amphistegina</i> spp. shows the largest potential distribution, apparently due to its temperature tolerance. Both <i>Archaias angulatus</i> and <i>Calcarina</i> spp. display potential distributions that cover currently uninhabited regions. Under climate conditions expected for the year 2050, all taxa should display latitudinal range expansions between 1 to 2.5 degrees both north- and southward. The modeled range projections suggest that some larger foraminifera may colonize biogeographic regions that so far seemed unsuitable. <i>Archaias angulatus</i> and <i>Calcarina</i> spp. also show an increase in habitat suitability within their native occurrence ranges, suggesting that their tolerance for maximum temperatures has yet not been fully exploited and that they benefit from ocean warming. Our findings suggest an increased role of larger foraminifera as carbonate producers and reef framework builders in future oceans.</p></div

Biogeographic distribution of <i>Amphistegina</i> spp. in the Atlantic Ocean.

<p>(A) Actual distribution and major isotherms (triangles: occurrence records used in the modeling process); (B) potential distribution under present climate conditions and corresponding isotherms; (C) potential distribution under future climate conditions.</p