Editorial

This is the second special issue to be developed from the international conference ‘At the Crossroads: New Directions in Teacher Education’, held at Canterbury Christ Church University in July 2012, which brought together over 200 scholars from 16 countries. As well as a range of methodological approaches to research in teacher education, represented in the studies published in the previous special issue (Vol. 6 issue 1, March 2014), many of the conference papers focussed on the development of innovative practice in initial teacher education. The five papers presented here, which have been updated for this special issue, illustrate some of these exciting initiatives

Editorial

Editorial special issue 1, Methodological approaches to researching teacher education: The idea for this special issue of TEAN developed from the international conference ‘At the Crossroads: New Directions in Teacher Education’, held at Canterbury Christ Church University in July 2012, which brought together over 200 scholars from 16 countries. It was striking that a sizeable number of papers focussed on specific methodologies used in researching teacher education, representing a growing interest in this area. The six articles published here, originally presented at the conference, represent just some of the different and innovative methodological approaches being used in current studies

The Alysiinae (Hym., Braconidae) parasites of the Agromyzidae (Diptera). V. The parasites of Liriomyza Mik and certain small genera of Phytomyzinae.

1. Dieser Artikel ist der fünfte einer Reihe und behandelt die europäischen Alysiinae-Parasiten der folgenden Gattungen von Phytomyzinae: Amauromyza Hendel, Campanulomyza Nowakowski, Trilobomyza Hendel, Melanophytobia Hering, Metopomyza Enderlein, Liriomyza Mik, Calycomyza Hendel und Pseudonapomyza Hendel. Die Parasiten gehören zu drei Gattungen von Dacnusini (Coloneura, Dacnusa und Chorebus) und zu zwei Gattungen außerhalb der Dacnusini, Dapsilarthra und Pseudopezomachus. - 2. Priapsis Nixon wird mit Coloneura Förster synonymisiert und eine neue Bestimmungstabelle für die Coloneura-Arten mitgeteilt. An der Dacnusa·Tabelle in Teil III (Griffiths, 1966b) werden Revisionen vorgenommen. Ferner werden Bestimmungstabellen für die Parasiten bestimmter Wirtsgruppen aufgestellt, um die Identifizierung gezogenen Materials zu erleichtern. - 3. Die meisten der in diesem Artikel behandelten Dacnusini zeigten einen hohen Grad von Wirtsspezifik, obwohl einige interessante Beispiele von disjunktiver Monophagie auftauchten. Es wurde eine neue vollständige Liste von Wirten und Parasiten für Europa aufgestellt, in der die Revisionen früherer Feststellungen berücksichtigt sind. - 4. Es werden siebzehn neue Arten beschrieben, davon zwei bei Dapsilarthra, zwei bei Coloneura, eine bei Dacnusa und zwölf bei Chorebus.Nomenklatorische HandlungenPriapsis Nixon, 1943 (Braconidae), syn. n. of Coloneura Förster, 1862amauromyzae Griffiths, 1968 (Chorebus), spec. n.artemisiellus Griffiths, 1968 (Chorebus), spec. n.asphodeli Griffiths, 1968 (Chorebus), spec. n.avesta (Nixon, 1944) (Chorebus), comb. n. hitherto Dacnusa avestacambricus Griffiths, 1968 (Chorebus), spec. n.daimenes (Nixon, 1945) (Chorebus), comb. n. hitherto Dacnusa daimenesdirona (Nixon, 1945) (Chorebus), comb. n. hitherto Dacnusa dironaincertus (Goureau, 1851) (Chorebus), comb. n. hitherto Dacnusa incertamelanophytobiae Griffiths, 1968 (Chorebus), spec. n.misellus (Marshall, 1897) (Chorebus), comb. n. hitherto Dacnusa misellapseudomisellus Griffiths, 1968 (Chorebus), spec. n.schlicki Griffiths, 1968 (Chorebus), spec. n.subfuscus Griffiths, 1968 (Chorebus), spec. n.testaceipes Griffiths, 1968 (Chorebus), spec. n.trilobomyzae Griffiths, 1968 (Chorebus), spec. n.varuna (Nixon, 1945) (Chorebus), comb. n. hitherto Dacnusa varunavenustus (Tobias, 1962) (Chorebus), comb. n. hitherto Dacnusa venustaveratri Griffiths, 1968 (Chorebus), spec. n.xanthaspidae Griffiths, 1968 (Chorebus), spec. n.ate (Nixon, 1943) (Coloneura), comb. n. hitherto Dacnusa atedanica Griffiths, 1968 (Coloneura), spec. n.dice (Nixon, 1943) (Coloneura), comb. n. hitherto Priapsis dicesiciliensis Griffiths, 1968 (Coloneura), spec. n.groschkeana Griffiths, 1968 (Dacnusa), spec. n.levisulca Griffiths, 1968 (Dapsilarthra), spec. n.testacea Griffiths, 1968 (Dapsilarthra), spec. nov.1. This paper, the fifth oi aseries, deals with the Alysiinae parasites in Europe of the following genera of Phytomyzinae: Amauromyza Hendel, Campanulomyza Nowakowski, Trilobomyza Hendel, Melanophytobia Hering, Metopomyza Enderlein, Liriomyza Mik, Calycomyza Hendel and Pseudonapomyza Hendel. The parasites belong to three genera of Dacnusini (Coloneura, Dacnusa and Chorebus) and two non-Dacnusine genera, Dapsilarthra and Pseudopezomachus. - 2. Priapsis Nixon is synonymised with Coloneura Förster and a new key to Coloneura species given. Revisions are given to the key to Dacnusa in Part III (Griffiths, 1966b). Keys are also given to the parasites of certain host-groups, to facilitate the identification of bred material. - 3. Most oi the Dacnusini treated in this paper show a high degree oi host specificity, although some interesting examples oi disjunctive monophagy have come to light. A complete host / parasite list for Europe has again been prepared, including revision of previous records. - 4. Seventeen new species are described, two in Dapsilarthra, two in Coloneura, one in Dacnusa and twelve in Chorebus.Nomenclatural ActsPriapsis Nixon, 1943 (Braconidae), syn. n. of Coloneura Förster, 1862amauromyzae Griffiths, 1968 (Chorebus), spec. n.artemisiellus Griffiths, 1968 (Chorebus), spec. n.asphodeli Griffiths, 1968 (Chorebus), spec. n.avesta (Nixon, 1944) (Chorebus), comb. n. hitherto Dacnusa avestacambricus Griffiths, 1968 (Chorebus), spec. n.daimenes (Nixon, 1945) (Chorebus), comb. n. hitherto Dacnusa daimenesdirona (Nixon, 1945) (Chorebus), comb. n. hitherto Dacnusa dironaincertus (Goureau, 1851) (Chorebus), comb. n. hitherto Dacnusa incertamelanophytobiae Griffiths, 1968 (Chorebus), spec. n.misellus (Marshall, 1897) (Chorebus), comb. n. hitherto Dacnusa misellapseudomisellus Griffiths, 1968 (Chorebus), spec. n.schlicki Griffiths, 1968 (Chorebus), spec. n.subfuscus Griffiths, 1968 (Chorebus), spec. n.testaceipes Griffiths, 1968 (Chorebus), spec. n.trilobomyzae Griffiths, 1968 (Chorebus), spec. n.varuna (Nixon, 1945) (Chorebus), comb. n. hitherto Dacnusa varunavenustus (Tobias, 1962) (Chorebus), comb. n. hitherto Dacnusa venustaveratri Griffiths, 1968 (Chorebus), spec. n.xanthaspidae Griffiths, 1968 (Chorebus), spec. n.ate (Nixon, 1943) (Coloneura), comb. n. hitherto Dacnusa atedanica Griffiths, 1968 (Coloneura), spec. n.dice (Nixon, 1943) (Coloneura), comb. n. hitherto Priapsis dicesiciliensis Griffiths, 1968 (Coloneura), spec. n.groschkeana Griffiths, 1968 (Dacnusa), spec. n.levisulca Griffiths, 1968 (Dapsilarthra), spec. n.testacea Griffiths, 1968 (Dapsilarthra), spec. nov

The Alysiinae (Hym., Braconidae) parasites of the Agromyzidae (Diptera). VI. The parasites of Cerodontha Rondani s. l.

1. Der sechste Teil der vorliegenden Serie beschäftigt sich mit den europäischen Alysiinae-Parasiten der Gattung Cerodontha Rondani in ihrer von Nowakowski (1962) vorgeschlagenen Umgrenzung. Die Parasiten gehören zu vier Dacnusini-Gattungen (Laotris, Exotela, Dacnusa und Chorebus) und zu der außerhalb der Dacnusini stehenden Gattung Dapsilarthra. - 2. Für verschiedene Gruppen europäischer Chorebus-Arten einschließlich der affinis-Gruppe (die in vorliegender Arbeit erstmalig in dieser Form umgrenzt wird) und für den sehr schwierigen ovalis/lateralis-Komplex werden revidierte Bestimmungstabellen gegeben. Auch für die Parasiten bestimmter Wirtsgruppen werden Tabellen zur Unterscheidung angeführt, um die Determination gezüchteten Materials zu erleichtern. - 3. Von den Dacnusini-Parasiten dieses Publikationsteiles zeigen alle Laotris- und Chorebus-Arten einen hohen Grad von Wirtsspezifität; nur die eine Exotela und die zwei Dacnusa-Arten greifen auch andere Agromyziden-Gattungen an. Wiederum wurde eine komplette Wirt-Parasiten-Liste zusammengestellt, die gleichzeitig eine Revision früherer Berichte für Europa berücksichtigt. - 4. Vierzehn neue Arten werden beschrieben, eine Dapsilarthra-, eine Laotris- und zwölf Chorebus-Spezies.Nomenklatorische Handlungenagraules (Nixon, 1945) (Chorebus), comb. n. hitherto Dacnusa agraulesasperrimus Griffiths, 1968 (Chorebus), spec. n.asramenes (Nixon, 1945) (Chorebus), comb. n. hitherto Dacnusa asramenescytherea (Nixon, 1937) (Chorebus), comb. n. hitherto Dacnusa cythereadifficilis Griffiths, 1968 (Chorebus), spec. n.diremtus (Nees, 1834) (Chorebus), comb. n. hitherto Alysia diremtaenephes (Nixon, 1945) (Chorebus), comb. n. hitherto Dacnusa enephesfordi (Nixon, 1954) (Chorebus), comb. n. hitherto Gyrocampa fordiganesa (Nixon, 1945) (Chorebus), comb. n. hitherto Dacnusa ganesagracilipes (Thomson, 1895) (Chorebus), comb. n. hitherto Dacnusa (Dacnusa) gracilipeshumeralis Griffiths, 1968 (Chorebus), spec. n.iridis Griffiths, 1968 (Chorebus), spec. n.lanigerus (Stelfox, 1957) (Chorebus), comb. n. hitherto Gyrocampa lanigeramerella (Nixon, 1937) (Chorebus), comb. n. hitherto Dacnusa merellametallicus Griffiths, 1968 (Chorebus), spec. n.nigriscaposus (Nixon, 1949) (Chorebus), comb. n. hitherto Gyrocampa nigriscaposanobilis Griffiths, 1968 (Chorebus), spec. n.pelion (Nixon, 1944) (Chorebus), comb. n. hitherto Dacnusa pelionpoemyzae Griffiths, 1968 (Chorebus), spec. n.rubicundus Griffiths, 1968 (Chorebus), spec. n.siniffa (Nixon, 1937) (Chorebus), comb. n. hitherto Dacnusa siniffastilifer Griffiths, 1968 (Chorebus), spec. n.subasper Griffiths, 1968 (Chorebus), spec. n.transversus (Nixon, 1954) (Chorebus), comb. n. hitherto Dacnusa transversavernalis Griffiths, 1968 (Chorebus), spec. n.vitripennis Griffiths, 1968 (Chorebus), spec. n.calliope Nixon, 1944 (Dacnusa), syn. n. of Dacnusa cytherea (Nixon, 1937)tesmia Nixon, 1944 (Dacnusa), syn. n. of Dacnusa cytherea (Nixon, 1937)fuscula Griffiths, 1968 (Dapsilarthra), spec. n.propodealis Nixon, 1949 (Gyrocampa), syn. n. of Chorebus nigriscaposus (Nixon, 1949)rupestris Griffiths, 1968 (Laotris), spec. n.1. This paper, the sixth of aseries, deals with the Alysiinae parasites in Europe of Cerodontha Rondani in the wide sense first proposed by Nowakowski (1962). The parasites belong to four genera of Dacnusini (Laotris, Exotela, Dacnusa and Chorebus) and the non-Dacnusine genus Dapsilarthra. - 2. Revised keys are given to the European representatives of several groups of Chorebus species, including the affinis group (a concept here proposed for the first time) and the very difficult ovalisjlateralis complex. Keys are also given to the parasites of certain host-groups, to facilitate the identification of bred material. - 3. Of the Dacnusini parasites treated in this paper, all the Laotris and Chorebus species exhibit a high degree of host specificity, but the single Exotela and two Dacnusa species are also known to attack other genera of Agromyzidae. A complete hostjparasite list has again been prepared, including revision of previous re cords for Europe. - 4. Fourteen new species are described, one in Dapsilarthra, one in Laotris and twelve in Chorebus. Nomenclatural Actsagraules (Nixon, 1945) (Chorebus), comb. n. hitherto Dacnusa agraulesasperrimus Griffiths, 1968 (Chorebus), spec. n.asramenes (Nixon, 1945) (Chorebus), comb. n. hitherto Dacnusa asramenescytherea (Nixon, 1937) (Chorebus), comb. n. hitherto Dacnusa cythereadifficilis Griffiths, 1968 (Chorebus), spec. n.diremtus (Nees, 1834) (Chorebus), comb. n. hitherto Alysia diremtaenephes (Nixon, 1945) (Chorebus), comb. n. hitherto Dacnusa enephesfordi (Nixon, 1954) (Chorebus), comb. n. hitherto Gyrocampa fordiganesa (Nixon, 1945) (Chorebus), comb. n. hitherto Dacnusa ganesagracilipes (Thomson, 1895) (Chorebus), comb. n. hitherto Dacnusa (Dacnusa) gracilipeshumeralis Griffiths, 1968 (Chorebus), spec. n.iridis Griffiths, 1968 (Chorebus), spec. n.lanigerus (Stelfox, 1957) (Chorebus), comb. n. hitherto Gyrocampa lanigeramerella (Nixon, 1937) (Chorebus), comb. n. hitherto Dacnusa merellametallicus Griffiths, 1968 (Chorebus), spec. n.nigriscaposus (Nixon, 1949) (Chorebus), comb. n. hitherto Gyrocampa nigriscaposanobilis Griffiths, 1968 (Chorebus), spec. n.pelion (Nixon, 1944) (Chorebus), comb. n. hitherto Dacnusa pelionpoemyzae Griffiths, 1968 (Chorebus), spec. n.rubicundus Griffiths, 1968 (Chorebus), spec. n.siniffa (Nixon, 1937) (Chorebus), comb. n. hitherto Dacnusa siniffastilifer Griffiths, 1968 (Chorebus), spec. n.subasper Griffiths, 1968 (Chorebus), spec. n.transversus (Nixon, 1954) (Chorebus), comb. n. hitherto Dacnusa transversavernalis Griffiths, 1968 (Chorebus), spec. n.vitripennis Griffiths, 1968 (Chorebus), spec. n.calliope Nixon, 1944 (Dacnusa), syn. n. of Dacnusa cytherea (Nixon, 1937)tesmia Nixon, 1944 (Dacnusa), syn. n. of Dacnusa cytherea (Nixon, 1937)fuscula Griffiths, 1968 (Dapsilarthra), spec. n.propodealis Nixon, 1949 (Gyrocampa), syn. n. of Chorebus nigriscaposus (Nixon, 1949)rupestris Griffiths, 1968 (Laotris), spec. n

The role of turbulent mixing in an overturning circulation maintained by surface buoyancy forcing

The role of externally imposed rates of small-scale mixing in an overturning circulation forced by differential surface buoyancy fluxes is examined in a laboratory experiment. The circulation occupies the full volume and involves a dense turbulent plume against the endwall and a broad upwelling throughout the interior. For strong externally imposed stirring, turbulent diffusion is the primary means of vertical density transport in the flow, and the dependence of the equilibrated circulation on the mixing rate accords with a theoretical model; the overturning rate increases as the 1/ 4 power of the turbulent diffusivity. For weak externally imposed stirring, advection is the dominant mechanism of vertical density transport, and the circulation is independent of the rate of external stirring. The rate of vertical density transport is parameterized as a bulk diffusivity obtained from different methods, including one from a Munk-like advection-diffusion balance and another from the transport of buoyancy across the surface. For strong stirring, the bulk diffusivities returned by the various methods agree with the externally imposed mixing rate. However, the parameterizations implicitly include a nondiffusive component of vertical transport associated with advection of the density field and it is shown that, for weak stirring, the bulk diffusivities exceed the externally imposed mixing rate. For the oceans, results suggest that the primary effect of mixing (with energy sourced from winds, tides, and convection) is to deepen the thermocline, thereby influencing the entrainment and consequent vertical transport of density in the dense sinking regions. It is concluded that this advective transport of density, and not vertical mixing, is crucial for coupling the surface to the abyss

Completing the mechanical energy pathways in turbulent Rayleigh-Bénard convection

A new, more complete view of the mechanical energy budget for Rayleigh-Bénard convection is developed and examined using three-dimensional numerical simulations at large Rayleigh numbers and Prandtl number of 1. The driving role of available potential e

When do marginal seas and topographic sills modify the ocean density structure?

We ask what effect marginal seas at high latitudes have on the abyssal densities and stratification of the oceans. Although marginal seas are not necessary for the formation of dense abyssal waters, topographic sills tend to restrict exchange flows and increase density differences. Laboratory experiments with a steady state large-scale overturning circulation, forced by a gradient in surface temperatures or heat fluxes, show that a marginal sea and topographic sill influence the abyssal density when the sill depth is less than twice the oceanic thermocline depth. The overflow over shallow sills interacts directly with the surrounding thermocline stratification, decreasing the abyssal density relative to an ocean with no marginal sea and increasing the density difference between the sea and the ocean. Experiments show that the effect of the sill depends on the surface boundary conditions and indicate a larger response for conditions approaching a prescribed distribution of temperature rather than of heat flux. Application of the results to the North Atlantic circulation suggests that the Greenland-Scotland Ridge is shallow enough to lead to a significant reduction of the density of North Atlantic Deep Water, and this is consistent with the conclusions from an analysis of water mass properties. The Greenland-Scotland Ridge is therefore likely to have a significant effect on the density structure and heat transport in the global oceans

Ocean stratification under oscillatory surface buoyancy forcing

Laboratory experiments with overturning circulation driven by oscillatory heat fluxes at one boundary are used to explore implications, for the ocean stratification, of a cyclic fluctuation in sea-surface buoyancy forcing. Fluctuations having a range of periods spanning the timescale for global recycling of the ocean volume through the thermocline are considered, with emphasis on inter-hemispheric \u27see-saw\u27 oscillations. Episodic sinking of dense water in the oceans is represented by convection in a channel with a base that is cooled over a central region and subjected to oscillatory heating near both ends, while providing a constant total heat input. For this simplified system the time-average interior temperature is found to be insensitive to the forcing period, but does vary with oscillation amplitude, whereas the interior fluctuations increase with forcing period. The circulation and density field are significantly different from those given by a steady forcing equal to the time-average of the actual oscillatory forcing, even for high-frequency oscillations. The results indicate that the overall stratification lies between that expected from the strongest phase of deep sinking and that given by symmetric sinking in both hemispheres. Glacial cycles are predicted to involve significant temperature fluctuations in the abyssal ocean. However, they are too short for the ocean to remain in quasi-equilibrium with the changing boundary conditions

Adjustment of the meridional overturning circulation and its dependence on depth of mixing

The relative roles of advective processes and mixing on the temporal adjustment of the meridional overturning circulation are examined, in particular the effects of mixing in either the abyssal or upper ocean. Laboratory experiments with convectively driven overturning and imposed stirring rates show that the circulation adjusts toward an equilibrium state on time scales governed by mixing in the upper boundary layer region but independent of the mixing rate in the bulk of the interior. The equilibrium state of the stratification is dependent only on the rate of mixing in the boundary layer. An idealized high-resolution ocean model shows adjustment (of a two-cell circulation) dominated primarily by the advective ventilation time scale, consistent with a view of the circulation determined by water mass transformation occurring primarily near the surface. Both the experiments and the model results indicate that adjustments of the circulation are controlled by surface buoyancy uptake (or rejection) and that the nonequilibrium circulation is dominated by advective processes, especially if the average abyssal ocean diffusivity is less than 3 × 10−5 m2 s−1