The anatomy of a woodland: Stand profile diagrams as an aid to problem-based learning in undergraduate forestry education

ABSTRACT Forestry education is poorly served with published examples of teaching and learning methods that enable students to engage actively with the discipline. This is not the case in other professional disciplines, such as the biology, medicine and engineering, where sub-disciplines have emerged and are devoted to the development and evaluation of optimum learning strategies. In this paper we present a short field-based practical that introduces forestry students to forest stand dynamics, applied forest ecology and silviculture. Students measure a series of tree and stand parameters in 2 contrasting forest types. They then analyze and interpret the data to develop their understanding. Reflective practice is built in by setting questions designed to promote enquiry and the self-identification of future avenues for personal development. The project, as described here, was devised for students at the National School of Forestry, England, but the principles could be applied to almost any learning environment. Planning within curriculum teams would be required to identify the appropriate location for this exercise in specific undergraduate programmes. Key words: forest stand dynamics, silviculture, problem-based learning, reflection, professional education RÉSUMÉ La formation académique en foresterie ne contient que très peu d' exemples de publication portant sur les méthodes d' enseignement et d'apprentissage qui pourraient permettre aux étudiants de s' engager sérieusement dans la discipline. Cela n' est pas le cas dans d'autres disciplines professionnelles, comme la biologie, la médecine et le génie, où se sont dévelop-pés de sous-disciplines consacrées au développement et à l' évaluation de stratégies optimales d'apprentissage. Nous présentons dans cet article un petit exercice pratique réalisé sur le terrain introduisant les étudiants en foresterie à la dynamique des peuplements forestiers, à l' écologie forestière appliquée et à la sylviculture. Les étudiants mesurent un groupe d'arbres et les paramètres de peuplement de deux types forestiers totalement différents. Ils analysent et interprè-tent par la suite les données pour bien comprendre la situation. L'apprentissage itératif s' effectue au moyen de questions conçues pour pousser les recherches et l'identification par la personne des orientations futures de son développement personnel. Le projet, tel que décrit ici a été élaboré pour les étudiants de la National School of Forestry en Angleterre, mais les principes pourraient être appliqués à presque tout environnement d'apprentissage. Une planification de la part de l' équipe chargé du programme de formation serait requise pour identifier l' endroit appropriée pour cet exercice réalisé au cours de certains programmes du baccalauréat. Mots clés : dynamique des peuplements forestiers, sylviculture, apprentissage à partir de cas, réflexion, formation professionnell

A disciplinary commons for database teaching

This paper discusses the experience of taking part in a disciplinary commons devoted to the teaching of database systems. It will discuss the structure of a disciplinary commons and our experience of the database version

Geology of the Llanidloes district : British Geological Survey Sheet 164

This Sheet Explanation provides a summary of the geology of the district covered by Geological 1:50 000 Series Map Sheet 164 (Llanidloes), published in 2010 as a Bedrock and Superficial Deposits edition. The district mostly lies within the county of Powys, but includes small parts of Ceredigion in the extreme west and south-west. Much of the western part of the district is occupied by the deeply dissected uplands of the Cambrian Mountains, a designated Area of Outstanding Natural Beauty. In this area the land rises to 740 m on the flanks of Plynlimon (Pumlumon Fawr), the highest summit in the range. It falls away towards the eastern part of the district into rolling countryside that includes the important catchment of the River Severn (Afon Hafren) and its tributaries, the largest of which are the rivers Carno, Trannon, Cerist, Clywedog and Dulas. A major reservoir (Llyn Clywedog) occupies the upper reaches of the Clywedog valley, its purpose being to regulate river discharge and groundwater levels within the catchment. The south-western part of the district is drained by the River Wye (Afon Gwy) and its tributaries, that flow south-eastwards via Llangurig. The sources of both the Severn and Wye are situated on the eastern flanks of Plynlimon within the western part of the district. The town of Llanidloes is the main centre of population, with smaller settlements at Llangurig, Carno, Trefeglwys, Caersws and Staylittle; the Newtown conurbation impinges on the eastern part of the district. Much of the district is given over to beef and dairy farming, although sheep are reared in the remote upland areas in the west and extensive forestry plantations have been developed in places. The Ordovician and Silurian rocks of the district have been exploited locally, in the past, as a source of building material and, recently, commercial quantities of sandstone aggregate have been excavated at Penstrowed Quarry [SO 0680 9100]. The district includes part of the Central Wales Mining Field from which substantial volumes of lead and zinc ore were extracted during the 19th and early 20th centuries. A number of former mine sites are still visible, notably along the Van, Nant-y-ricket, Dylife, Dyfngwm and Llanerchyraur lodes (Jones, 1922[1]; IGS, 1974), and the historic Bryntail Mine, below the Clywedog Dam has been restored as a site of industrial archaeological interest. The district is underlain by a succession of Late Ordovician (Ashgill) to Silurian sedimentary rocks, over 5 km thick, deposited between 450 and 420 million years ago in the Early Palaeozoic Welsh Basin (Figure P930911). The basin developed on a fragment of the ancient supercontinent of Gondwana, known as Eastern Avalonia (e.g. Pickering et al., 1988[2]), that drifted northwards to collide with the continents of Baltica and Laurentia during the Late Ordovician and Silurian (Soper and Hutton, 1984[3]; Soper and Woodcock, 1990[4]; Woodcock and Strachan, 2000[5]). To the east and the south of the basin lay the Midland Platform, a relatively stable shallow marine shelf that was subject to periodic emergence. The basinal sediments are predominantly deep marine turbiditic facies that were introduced into the district by density currents from southerly, south-easterly and north-westerly quadrants. Coeval shallower-water ‘shelfal’ sediments were deposited north and east of the district, and locally impinge on its northern margins. Thickness variations within the major sedimentary units suggest that, at times, syndepositional fault movements were an important control on their distribution. During late Silurian (Ludlow) times, shallowing of the basin occurred, and sandstones, variably interpreted as a turbiditic (Cave and Hains, 2001[6]) or storm-generated facies (Tyler and Woodcock, 1987[7]), were laid down over the eastern part of the district and adjacent areas. The shallowing was a result of tectonic reconfiguration of the basin, a precursor to the late Caledonian (Acadian) Orogeny that affected the region during the late Early Devonian, around 400 million years ag

Bipotential Adult Liver Progenitors Are Derived from Chronically Injured Mature Hepatocytes

SummaryAdult liver progenitor cells are biliary-like epithelial cells that emerge only under injury conditions in the periportal region of the liver. They exhibit phenotypes of both hepatocytes and bile ducts. However, their origin and their significance to injury repair remain unclear. Here, we used a chimeric lineage tracing system to demonstrate that hepatocytes contribute to the progenitor pool. RNA-sequencing, ultrastructural analysis, and in vitro progenitor assays revealed that hepatocyte-derived progenitors were distinct from their biliary-derived counterparts. In vivo lineage tracing and serial transplantation assays showed that hepatocyte-derived proliferative ducts retained a memory of their origin and differentiated back into hepatocytes upon cessation of injury. Similarly, human hepatocytes in chimeric mice also gave rise to biliary progenitors in vivo. We conclude that human and mouse hepatocytes can undergo reversible ductal metaplasia in response to injury, expand as ducts, and subsequently contribute to restoration of the hepatocyte mass

The Origins of [CII] Emission in Local Star-forming Galaxies

The [CII] 158um fine-structure line is the brightest emission line observed in local star-forming galaxies. As a major coolant of the gas-phase interstellar medium, [CII] balances the heating, including that due to far-ultraviolet photons, which heat the gas via the photoelectric effect. However, the origin of [CII] emission remains unclear, because C+ can be found in multiple phases of the interstellar medium. Here we measure the fractions of [CII] emission originating in the ionized and neutral gas phases of a sample of nearby galaxies. We use the [NII] 205um fine-structure line to trace the ionized medium, thereby eliminating the strong density dependence that exists in the ratio of [CII]/[NII] 122um. Using the FIR [CII] and [NII] emission detected by the KINGFISH and Beyond the Peak Herschel programs, we show that 60-80% of [CII] emission originates from neutral gas. We find that the fraction of [CII] originating in the neutral medium has a weak dependence on dust temperature and the surface density of star formation, and a stronger dependence on the gas-phase metallicity. In metal-rich environments, the relatively cooler ionized gas makes substantially larger contributions to total [CII] emission than at low abundance, contrary to prior expectations. Approximate calibrations of this metallicity trend are provided.Comment: 8 pages, accepted for publication in Ap

The emission by dust and stars of nearby galaxies in the Herschel KINGFISH survey

Using new far-infrared imaging from the Herschel Space Observatory with ancillary data from ultraviolet (UV) to submillimeter wavelengths, we estimate the total emission from dust and stars of 62 nearby galaxies in the KINGFISH survey in a way that is as empirical and model independent as possible. We collect and exploit these data in order to measure from the spectral energy distributions (SEDs) precisely how much stellar radiation is intercepted and re-radiated by dust, and how this quantity varies with galaxy properties. By including SPIRE data, we are more sensitive to emission from cold dust grains than previous analyses at shorter wavelengths, allowing for more accurate estimates of dust temperatures and masses. The dust/stellar flux ratio, which we measure by integrating the SEDs, has a range of nearly three decades (from 10(-2.2) to 10(0.5)). The inclusion of SPIRE data shows that estimates based on data not reaching these far-IR wavelengths are biased low by 17% on average. We find that the dust/stellar flux ratio varies with morphology and total infrared (IR) luminosity, with dwarf galaxies having faint luminosities, spirals having relatively high dust/stellar ratios and IR luminosities, and some early types having low dust/stellar ratios. We also find that dust/stellar flux ratios are related to gas-phase metallicity ((log(f(dust)/f(*)) over bar) = -0.66 +/- 0.08 and -0.22 +/- 0.12 for metal-poor and intermediate-metallicity galaxies, respectively), while the dust/stellar mass ratios are less so (differing by approximate to 0.2 dex); the more metal-rich galaxies span a much wider range of the flux ratios. In addition, the substantial scatter between dust/stellar flux and dust/stellar mass indicates that the former is a poor proxy of the latter. Comparing the dust/stellar flux ratios and dust temperatures, we also show that early types tend to have slightly warmer temperatures (by up to 5 K) than spiral galaxies, which may be due to more intense interstellar radiation fields, or possibly to different dust grain compositions. Finally, we show that early types and early-type spirals have a strong correlation between the dust/stellar flux ratio and specific star formation rate, which suggests that the relatively bright far-IR emission of some of these galaxies is due to ongoing (if limited) star formation as well as to the radiation field from older stars, which is heating the dust grains

Neurosteroid modulation of GABAergic neurotransmission in the central amygdala: A role for NMDA receptors

The neurosteroid 3α-hydroxy-5α-pregnan-20-one (allopregnanolone or ALLO) positively modulates GABAA receptors, an action that may contribute to the anxiolytic effects of ALLO. Recent evidence suggests that ALLO’s anxiolytic effects appear to be mediated by the amygdala, a key neural structure for emotional and cognitive behaviors. However, little is known regarding ALLO effects on amygdala physiology. We therefore explored ALLO effects on GABA neurotransmission in the central nucleus (Ce) of the amygdala, a major output nucleus involved in fear and anxiety. We recorded evoked GABAA receptor-mediated inhibitory postsynaptic currents (IPSCs) in Ce neurons using whole-cell patch clamp techniques. We observed that ALLO significantly reduced the amplitude of evoked GABAA receptor-mediated IPSCs. However, the effect of ALLO was occluded by the NMDA receptor antagonist D-APV. D-APV alone also reduced evoked IPSCs in Ce neurons. These results suggest that ALLO-induced reduction of GABAergic transmission in Ce appears to depend on neural network activity, possibly involving an NMDA receptor-mediated mechanism. These ALLO effects on GABAergic transmission in the central amygdala may play a role in mediating its anxiolytic actions

Effects of flood hazard visualization format on house purchasing decisions

We investigated how decision-making is affected by the visual presentation of flood hazard information. We exposed participants to different formats of flood hazard information while they simulated selecting a property to purchase. We compared three flood hazard formats: (i) maps currently used by the UK Environment Agency, (ii) tables that present flood level and frequency information and (iii) graphical representations depicting the level-frequency combination using a cartoon house image as a physical referent. In the experiment participants were presented, via computer screen, side-by-side information about two houses in a series of trials. Participants made a forced choice preference judgement between 108 different pairs of houses to indicate which they would purchase. Our findings indicate that when hazard information is presented in map format, individuals are less accurate in selecting lower-hazard houses, compared to when the same information is presented as a graphic representation of a house or as a table. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group

The thermal emission of the exoplanets WASP-1b and WASP-2b

We present a comparative study of the thermal emission of the transiting exoplanets WASP-1b and WASP-2b using the Spitzer Space Telescope. The two planets have very similar masses but suffer different levels of irradiation and are predicted to fall either side of a sharp transition between planets with and without hot stratospheres. WASP-1b is one of the most highly irradiated planets studied to date. We measure planet/star contrast ratios in all four of the IRAC bands for both planets (3.6-8.0um), and our results indicate the presence of a strong temperature inversion in the atmosphere of WASP-1b, particularly apparent at 8um, and no inversion in WASP-2b. In both cases the measured eclipse depths favor models in which incident energy is not redistributed efficiently from the day side to the night side of the planet. We fit the Spitzer light curves simultaneously with the best available radial velocity curves and transit photometry in order to provide updated measurements of system parameters. We do not find significant eccentricity in the orbit of either planet, suggesting that the inflated radius of WASP-1b is unlikely to be the result of tidal heating. Finally, by plotting ratios of secondary eclipse depths at 8um and 4.5um against irradiation for all available planets, we find evidence for a sharp transition in the emission spectra of hot Jupiters at an irradiation level of 2 x 10^9 erg/s/cm^2. We suggest this transition may be due to the presence of TiO in the upper atmospheres of the most strongly irradiated hot Jupiters.Comment: 10 pages, submitted to Ap