Challenges Using Extrapolated Family-level Macroinvertebrate Metrics in Moderately Disturbed Tropical Streams: a Case-study From Belize

Family-level biotic metrics were originally designed to rapidly assess gross organic pollution effects, but came to be regarded as general measures of stream degradation. Improvements in water quality in developed countries have reignited debate about the limitations of family-level taxonomy to detect subtle change, and is resulting in a shift back towards generic and species-level analysis to assess smaller effects. Although the scale of pollution characterizing past condition of streams in developed countries persists in many developing regions, some areas are still considered to be only moderately disturbed. We sampled streams in Belize to investigate the ability of family-level macroinvertebrate metrics to detect change in stream catchments where less than 30% of forest had been cleared. Where disturbance did not co-vary with natural gradients of change, and in areas characterized by low intensity activities, none of the metrics tested detected significant change, despite evidence of environmental impacts. We highlight the need for further research to clarify the response of metrics to disturbance over a broader study area that allows replication for confounding sources of natural variation. We also recommend research to develop more detailed understanding of the taxonomy and ecology of Neotropical macroinvertebrates to improve the robustness of metric use

Pathogenic Huntingtin Repeat Expansions in Patients with Frontotemporal Dementia and Amyotrophic Lateral Sclerosis.

We examined the role of repeat expansions in the pathogenesis of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) by analyzing whole-genome sequence data from 2,442 FTD/ALS patients, 2,599 Lewy body dementia (LBD) patients, and 3,158 neurologically healthy subjects. Pathogenic expansions (range, 40-64 CAG repeats) in the huntingtin (HTT) gene were found in three (0.12%) patients diagnosed with pure FTD/ALS syndromes but were not present in the LBD or healthy cohorts. We replicated our findings in an independent collection of 3,674 FTD/ALS patients. Postmortem evaluations of two patients revealed the classical TDP-43 pathology of FTD/ALS, as well as huntingtin-positive, ubiquitin-positive aggregates in the frontal cortex. The neostriatal atrophy that pathologically defines Huntington's disease was absent in both cases. Our findings reveal an etiological relationship between HTT repeat expansions and FTD/ALS syndromes and indicate that genetic screening of FTD/ALS patients for HTT repeat expansions should be considered

Evolution of Interstellar Ices

Abstract. Infrared observations, combined with realistic laboratory simulations, have revolutionized our understanding of interstellar ice and dust, the building blocks of comets. Ices in molecular clouds are dominated by the very simple molecules H2O, CH3OH, NH3, CO, CO2, and proba-bly H2CO and H2. More complex species including nitriles, ketones, and esters are also present, but at lower concentrations. The evidence for these, as well as the abundant, carbon-rich, inter-stellar, polycyclic aromatic hydrocarbons (PAHs) is reviewed. Other possible contributors to the interstellar/pre-cometary ice composition include accretion of gas-phase molecules and in situ pho-tochemical processing. By virtue of their low abundance, accretion of simple gas-phase species is shown to be the least important of the processes considered in determining ice composition. On the other hand, photochemical processing does play an important role in driving dust evolution and the composition of minor species. Ultraviolet photolysis of realistic laboratory analogs read-ily produces H2, H2CO, CO2, CO, CH4, HCO, and the moderately complex organic molecules: CH3CH2OH (ethanol), HC(=O)NH2 (formamide), CH3C(=O)NH2 (acetamide), R-CN (nitriles), and hexamethylenetetramine (HMT, C6H12N4), as well as more complex species including amides, ke-tones, and polyoxymethylenes (POMs). Inclusion of PAHs in the ices produces many species simila

A 10 MICRON SURVEY OF STAR FORMATION IN GALACTIC NUCLEI - VIRGO SPIRAL GALAXIES

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Infrared polarimetry of the nucleus of Centaurus A - The nearest blazar?

Original article can be found at: http://www.nature.com/nature/ Copyright Nature Publishing Group. DOI: 10.1038/322150a0 [Full text of this article is not available in the UHRA]As one of the nearest examples of an active galaxy, NGC5128 (Centaurus A) has been studied in detail over a wide range of wavelengths. The nucleus of the galaxy is seen clearly in the X-ray, radio and infrared, but is obscured in the optical by the prominent warped dust lane. We have made polarization observations of the infrared nucleus at wavelengths from 1.2 to 3.8 µm. We find that after correction for the polarization caused by the dust lane, and for dilution by starlight, the nucleus has a large intrinsic polarization of 9% at position angle 147°. This position angle is perpendicular to the direction of the X-ray and radio jet. We interpret the polarized emission from the nucleus as synchrotron radiation from a region whose magnetic field is parallel to the jet direction. The properties of the Cen A nucleus are essentially identical to those of the much more luminous blazars. This suggest that blazar-type activity extends over a very wide range in luminosity, and low-luminosity blazars may be common in elliptical galaxies.Peer reviewe

Investigating science teachers’ transformations when implementing inquiry-based teaching-learning sequences

In this study we aimed to investigate the most transformed/accepted aspects of scientific inquiry when it is implemented in classroom practice. Thirteen secondary school teachers participated in the study. The teachers were first involved in a professional development (PD) course aimed at familiarizing them with inquiry principles, using seven teaching-learning sequences (TLSs) as training contexts. Then, teachers implemented one TLS in their classrooms for at least 5 h. A knowledge transfer framework, Adaption and Re-Invention Model, was used to investigate teachers’ transfer of TLS in classroom practice. In particular, core and non-core elements of the TLSs were identified: core elements are essential features of inquiry teaching that should not be changed while implementing a TLS since they characterize it in a unique way. Non-core elements concern classroom management and activities timing and can be changed to fit the TLS into the specific educational context. Collected data have been audio/video recordings. Results show that most accepted aspects of inquiry teaching are related to data collection, support to students, activities timing, and homework tasks. Moreover, most teachers acted as resource persons and valued classroom discussions. Overall, our findings may usefully inform PD courses by providing evidence of teachers’ enactment of inquiry in their practice