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The rocky shores of the north-east Atlantic have been long studied. Our focus is from Gibraltar to Norway plus the Azores and Iceland. Phylogeographic processes shape biogeographic patterns of biodiversity. Long-term and broadscale studies have shown the responses of biota to past climate fluctuations and more recent anthropogenic climate change. Inter- and intra-specific species interactions along sharp local environmental gradients shape distributions and community structure and hence ecosystem functioning. Shifts in domination by fucoids in shelter to barnacles/mussels in exposure are mediated by grazing by patellid limpets. Further south fucoids become increasingly rare, with species disappearing or restricted to estuarine refuges, caused by greater desiccation and grazing pressure. Mesoscale processes influence bottom-up nutrient forcing and larval supply, hence affecting species abundance and distribution, and can be proximate factors setting range edges (e.g., the English Channel, the Iberian Peninsula). Impacts of invasive non-native species are reviewed. Knowledge gaps such as the work on rockpools and host–parasite dynamics are also outlined.
Background: Heterozygous loss-of-function mutations in the synaptic scaffolding gene SHANK2 are strongly associated with autism spectrum disorder (ASD). However, their impact on the function of human neurons is unknown. Derivation of induced pluripotent stem cells (iPSC) from affected individuals permits generation of live neurons to answer this question. Methods: We generated iPSCs by reprogramming dermal fibroblasts of neurotypic and ASD-affected donors. To isolate the effect of SHANK2, we used CRISPR/Cas9 to knock out SHANK2 in control iPSCs and correct a heterozygous nonsense mutation in ASD-affected donor iPSCs. We then derived cortical neurons from SOX1+ neural precursor cells differentiated from these iPSCs. Using a novel assay that overcomes line-to-line variability, we compared neuronal morphology, total synapse number, and electrophysiological properties between SHANK2 mutants and controls. Results: Relative to controls, SHANK2 mutant neurons have increased dendrite complexity, dendrite length, total synapse number (1.5-2-fold), and spontaneous excitatory postsynaptic current (sEPSC) frequency (3-7.6-fold). Conclusions: ASD-associated heterozygous loss-of-function mutations in SHANK2 increase synaptic connectivity among human neurons by increasing synapse number and sEPSC frequency. This is partially supported by increased dendrite length and complexity, providing evidence that SHANK2 functions as a suppressor of dendrite branching during neurodevelopment.
Over the past 30 years, the number of US doctoral anthropology graduates has increased by about 70%, but there has not been a corresponding increase in the availability of new faculty positions. Consequently, doctoral degree-holding archaeologists face more competition than ever before when applying for faculty positions. Here we examine where US and Canadian anthropological archaeology faculty originate and where they ultimately end up teaching. Using data derived from the 2014–2015 AnthroGuide, we rank doctoral programs whose graduates in archaeology have been most successful in the academic job market; identify long-term and ongoing trends in doctoral programs; and discuss gender division in academic archaeology in the US and Canada. We conclude that success in obtaining a faculty position upon graduation is predicated in large part on where one attends graduate school.
There is now evidence that at least some cometary nuclei are dark and red. Cometary ices prepared from combinations of CH4 with H2O and sometimes NH3 were irradiated at 77 K by corona discharge. CH4 - containing ice reddened and darkened at a dose ~1011 erg cm−2 over a period of ~1 hour. Upon evaporation of the now yellowish, irradiated ice, a slightly yellowish colored solid film remains on the walls of the container at room temperature. Transmission measurements of this organic film (called cometary tholin) were made from 0.2 μm to 50 μm wavelength. Strong UV absorption is seen from 0.45 μm to 0.2 μm. Above 0.45 μm, the spectrum remains flat to ~1.3 μm in the near infrared, except for a very small feature near 1.15 μm. A medium sized feature appears centered at 1.4 μm with shoulders at both sides and a nearby weaker feature at 1.52 μm. A strong feature appears at 1.9 μm accompanied by a smaller feature at 1.78 μm. in the region 2.5 μm to 50 μm, the infrared spectrum was taken by dispersing the film in a CsI matrix. Bands are found at 2.92(M), 3.36(S), 3.40(S), 3.46(M), 3.48(M), 5.75(M), 5.99(S), 6.21(M), 6.83(M), 7.30(S), 7.81(W), 8.89(M), 9.26(M), 20.00(W), 22.22(W), and 28.57(W) micrometers, suggesting complex organics including alkane, alkene, aldehyde, and carboxylic acid functional groups. These results are also relevant to UV and cosmic ray processing of interstellar grains, and to icy bodies in the outer solar system.
In the prevailing icy conglomerate model of the cometary nucleus, the outer surface is processed by galactic cosmic rays in the Oort cloud. Most ices composed of CH4, along with H2O and/or NH3, studied in our laboratory redden and darken upon charged particle irradiation from a high frequency corona discharge at 77 K. Spectral reflectance relative to a BaSO4 standard in the wavelength interval 0.39 μm to 0.70 μm was measured for incidence angle, i = 0° and emission angle, ε = −4°. CH4-containing ice at 77 K was modified at a dose ~1011 erg cm−2 over a period of ~1 hour. Progressive darkening followed continued irradiation. The ratio of the red to blue reflectance [R(λ = 0.70 μm)/R(λ = 0.40 μm)] changed from 0.9 to ~1.4. Using techniques of ellipsometric polarimetry, we are investigating the detailed optical properties (complex refractive index) of these ices before and after irradiation. These results may then be compared with the properties of cometary coma particles predicted by recent light scattering models to determine which classes of laboratory-produced materials best match the population of dark, reddish particles which seem to be prevalent in some cometary comae.
Our understanding of the complex relationship between schizophrenia symptomatology and etiological factors can be improved by studying brain-based correlates of schizophrenia. Research showed that impairments in value processing and executive functioning, which have been associated with prefrontal brain areas [particularly the medial orbitofrontal cortex (MOFC)], are linked to negative symptoms. Here we tested the hypothesis that MOFC thickness is associated with negative symptom severity.
This study included 1985 individuals with schizophrenia from 17 research groups around the world contributing to the ENIGMA Schizophrenia Working Group. Cortical thickness values were obtained from T1-weighted structural brain scans using FreeSurfer. A meta-analysis across sites was conducted over effect sizes from a model predicting cortical thickness by negative symptom score (harmonized Scale for the Assessment of Negative Symptoms or Positive and Negative Syndrome Scale scores).
Meta-analytical results showed that left, but not right, MOFC thickness was significantly associated with negative symptom severity (βstd = −0.075; p = 0.019) after accounting for age, gender, and site. This effect remained significant (p = 0.036) in a model including overall illness severity. Covarying for duration of illness, age of onset, antipsychotic medication or handedness weakened the association of negative symptoms with left MOFC thickness. As part of a secondary analysis including 10 other prefrontal regions further associations in the left lateral orbitofrontal gyrus and pars opercularis emerged.
Using an unusually large cohort and a meta-analytical approach, our findings point towards a link between prefrontal thinning and negative symptom severity in schizophrenia. This finding provides further insight into the relationship between structural brain abnormalities and negative symptoms in schizophrenia.
The Medium-l Program of the Michelson Doppler Imager (MDI) instrument on board SOHO provides continuous observations of oscillation modes of angular degree, l, from 0 to ∼ 300. The initial results show that the noise in the Medium-l oscillation power spectrum is substantially lower than in ground-based measurements. This enables us to detect lower amplitude modes and, thus, to extend the range of measured mode frequencies. The MDI observations also reveal the asymmetry of oscillation spectral lines. The line asymmetries agree with the theory of mode excitation by acoustic sources localized in the upper convective boundary layer. The sound-speed profile inferred from the mean frequencies gives evidence for a sharp variation at the edge of the energy-generating core. In a thin layer just beneath the convection zone, helium appears to be less abundant than predicted by theory. Inverting the multiplet frequency splittings from MDI, we detect significant rotational shear in this thin layer.
We present an overview of the survey for radio emission from active stars that has been in progress for the last six years using the observatories at Fleurs, Molonglo, Parkes and Tidbinbilla. The role of complementary optical observations at the Anglo-Australian Observatory, Mount Burnett, Mount Stromlo and Siding Spring Observatories and Mount Tamborine are also outlined. We describe the different types of star that have been included in our survey and discuss some of the problems in making the radio observations.
We obtained simultaneous images of solar plage on 7 May 1991 with Goddard Space Flight Center’s Solar EUV Rocket Telescope and Spectrograph (SERTS), the Very Large Array (VLA), and the NASA/NSO spectromagnetograph at Kitt Peak. Using intensity ratios of Fe XVI to Fe XV emission lines, we find that the coronal plasma temperature is 2.5 ± 0.3 ×lO6 K throughout the region. The column emission measure ranges from 2.6 × 1027 to 1.3 × 1028 cm−5. The calculated structure and intensity of the 20 cm wavelength thermal bremsstrahlung emission from the hot plasma observed by SERTS is quite similar to the observed structure and intensity of the 20 cm microwave emission observed by the VLA. Using the revised coronal iron abundance of Meyer (1991, 1992), we find no evidence for either cool absorbing plasma or for contributions from thermal gyroemission. Combining the observed microwave polarization and the SERTS plasma parameters, we calculate a map of the coronal longitudinal magnetic field. The resulting values, ~ 30 – 60 Gauss, are comparable to extrapolated values of the potential field at heights of 5,000 and 10,000 km.
The brightnesses of Titan and Neptune have been monitored photo-electrically at 472 and 551 nm since 1972 at the Lowell Observatory, yielding annual mean magnitudes accurate to 0.3 percent (0.003 mag). Both objects increased steadily in brightness until 1976 and declined thereafter (Lockwood 1977, Lockwood and Thompson 1979). The range of variation was about 0.08 mag for Titan and 0.03 mag for Neptune.
Historically, American Indian/Alaska Native (AI/AN) populations have suffered excess morbidity and mortality from influenza. We investigated the risk factors for death from 2009 pandemic influenza A(H1N1) in persons residing in five states with substantial AI/AN populations. We conducted a case-control investigation using pandemic influenza fatalities from 2009 in Alaska, Arizona, New Mexico, Oklahoma and Wyoming. Controls were outpatients with influenza. We reviewed medical records and interviewed case proxies and controls. We used multiple imputation to predict missing data and multivariable conditional logistic regression to determine risk factors. We included 145 fatal cases and 236 controls; 22% of cases were AI/AN. Risk factors (P < 0·05) included: older age [adjusted matched odds ratio (mOR) 3·2, for >45 years vs. <18 years], pre-existing medical conditions (mOR 7·1), smoking (mOR 3·0), delayed receipt of antivirals (mOR 6·5), and barriers to healthcare access (mOR 5·3). AI/AN race was not significantly associated with death. The increased influenza mortality in AI/AN individuals was due to factors other than racial status. Prevention of influenza deaths should focus on modifiable factors (smoking, early antiviral use, access to care) and identifying high-risk persons for immunization and prompt medical attention.
The influence of higher processing temperatures on the formation reaction of Cu(In,Ga)(Se,S)2 thin films using a three step reactive annealing process and on the device performance has been investigated. High process temperatures generally lead to the formation of larger grains, decrease the amount of void formation and their distribution at the back Mo/Cu(In,Ga)(Se,S)2 interface, and lead to a much faster formation reaction that shortens the overall reaction process. However, high temperature processing also leads to a decrease in device performance. A loss in open circuit voltage and fill factor could be attributed to enhanced interface recombination processes for the samples fabricated at higher process temperatures, which itself may be caused by a lack of Na and subsequent poor passivation of interface defect states. The lack of Na resulted in a decrease in free charge carrier concentration by two orders of magnitude.