770 research outputs found
Corethrella (Corethrella) bipigmenta Borkent & Grafe, new species
No full text<i>Corethrella</i> (<i>Corethrella</i>) <i>bipigmenta</i> Borkent & Grafe, new species <p>(Figs. 2 C, 4D, 6D, 8D, 9D, 12D, 13D, 15B)</p> <p> DIAGNOSIS: <i>Male adult.</i> Unknown. <i>Female adult.</i> Only extant species of <i>Corethrella</i> in the Palaearctic, Oriental, Oceanian and northern Australasian Regions with the combination of no pigmentation distal to the single distinct midlength wing band (no subapical band) (Fig. 12D), flagellomeres 1–4 elongate, each similar in length to flagellomere 5 (Fig. 8 D), with non-discrete darker pigmentation on the basal 0.5 of the midfemur and basal 0.3–0.4 of the hind femur, uniformly yellow or light brown hind tibia (Fig. 9D), and abdominal tergites each with anterolateral darker pigmentation (Fig. 13D). Only extant species in Borneo with the combination of flagellomeres 1–4 elongate, each similar in length to flagellomere 5 (Fig. 8 D) and palpal segments 1 and 2 dark brown and contrasting with pale segments 3 and 4 (5 grading from pale to medium brown) (Fig. 6 D).</p> <p> DESCRIPTION: <i>Male adult</i>. Unknown. <i>Female adult.</i> Descriptive statistics: See Tables 1 –5. <b>Head</b>: Outline in anterior view somewhat circular (Fig. 6 D). Coronal suture elongate, extending ventrally past ommatidia. Two large setae on frons between ventromedial area of ommatidia (as in Fig. 16B). Antenna uniformly medium brown; pedicel with distinctive elongate, stout setae. Antennal flagellomeres as in Fig. 8 D; sensilla coeloconica on flagellomeres 1–2, 9–13, only flagellomere 1 with more than one; flagellomere 13 with well-developed apical bifurcation. Clypeus somewhat square. Mandible with moderately small, pointed teeth. Palpus (Fig. 6 D) with segments 1–2 dark brown, segments 3–5 light brown, segment 5 darker apically; segment 3 swollen apically. <b>Thorax</b> (Fig. 9D): Scutum, scutellum mostly light to medium brown, contrasting with darker brown pleura; pale sclerites around base of wing. Posterior portion of dorsocentral row with 2 elongate setae situated somewhat lateral to one another. Prescutal suture elongate, thick, uninterrupted, extending to near dorsocentral row of setae.</p> <p> Anterior anepisternum divided diagonally by sinuous suture, dorsal portion about equal to ventral portion. Ventral portion of posterior anepisternum triangular, uniformly brown, with anterodorsal margin not thick. <b>Wing</b> (Fig. 12D): Apex of R2 slightly distal to apex of M1. Anterior margin with differently, discretely pigmented scales (indicating anterior margin of midlength band), with midlength band, with darker more basal scales restricted to vein C, Sc, slightly in more posterior veins, with basal scales on posterior margin of wing dark; veins (other than costa and wing margin) with well-developed scales. Halter medium brown, equal to or slightly lighter than scutellum. <b>Legs</b> (Fig. 9D): Light brown, with about basal 0.5 of forefemur slightly darker, about basal 0.5 of midfemur darker, about basal 0.3–0.4 of hind femur darker; with darker pigmentation not discrete. With only slender setae, lacking scales. Midleg with thick, subapical setae on each of at least tarsomeres 1–3. Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Empodia thick. <b>Abdomen</b> (Fig. 13D): Tergites 2–7 pale or light brown with anterolateral corners more darkly pigmented, tergite 8 pale or light brown, sternites light brown with sternites 2–6 with anterior portions medium brown, posterior margins pale, sternites 7–8 medium brown. Cercus medium light brown.</p> <p> <i>Immature stages</i>. Unknown.</p> <p> DISTRIBUTION AND BIONOMICS: <i>Corethrella bipigmenta</i> is known only from steep terrain in the mature mixed dipterocarp forest (Figs. 1 E, F) of Ulu Temburong National Park, Brunei, at elevations of 50–120 meters (Fig. 15B). Three females in the type series were collected on 22-VII-2006 from a calling male <i>Megophrys nasuta</i> (Schlegel) at 8:30 PM (Fig. 2 C). A photograph by the second author (Fig. 2 C) shows numerous identical looking female <i>Corethrella</i> on and surrounding the frog: seven were on the legs, two were on the back, and at least 10 were on nearby substrate. Further specimens were collected from other <i>M. nasuta</i> and one other frog species (Table 7). This species has not yet been collected with a frog-call trap.</p> <p> TAXONOMIC DISCUSSION: The three type specimens of <i>C. bipigmenta</i> were noted by Borkent (2008) in the taxonomic discussion of <i>C. nippon</i> (but mistakenly stated as coming from Sungai Belalong). This species is very similar to <i>C. nanoantennalis</i> but differs in the relative lengths of flagellomeres 1–4.</p> <p> <i>Corethrella bipigmenta</i> is placed in the <i>drakensbergensis</i> species group for the same reason that <i>C. nanoantennalis</i> was placed there, along with the same caveats (Fig. 19). However, it appears that this species has synapomorphy 40 (pedicel with strong setae), which would place it elsewhere in the phylogeny of the Corethrellidae. We are inclined however, to question the validity of this synapomorphy – it is often difficult to interpret consistently in specimens and its distribution may have been misrepresented by Borkent (2008).</p> <p> TYPES: Holotype, female adult on microscope slide, labeled " HOLOTYPE <i>Corethrella bipigmenta</i> Borkent and Grafe ", "Tributary of Sungai Temburong in Temburong district of Brunei Darussalam, 115° 09'E, 4° 33'N, 22-VIII-2006, U. Grafe, CD2069" (CNCI). Paratypes on microscope slides: 2 Ƥ, labeled as for holotype (1, CNCI; 1 UBD). Paratypes on pins: 2 Ƥ, from Kuala Belalong, Ulu Temburong NP, Brunei, 50 m, 23-VII-2007 (CNCI); 4 Ƥ, from Sungai Esu, Ulu Temburong NP, Brunei, 60 m, 11-VII-2008 (CNCI); 2 Ƥ, from Sungai Baki, Ulu Temburong NP, Brunei, 120 m, 18-VII-2008 (1 CNCI; 1 UBD); 1 Ƥ, Sungai Mata Ikan, Ulu Temburong NP, Brunei, 110 m, 10-VII-2008, (UBD).</p> <p> DERIVATION OF SPECIFIC EPITHET: The name <i>bipigmenta</i> (two, pigment) refers to differently pigmented palpal segments 1–2 (dark) and segments 3–5 (lightly pigmented) of females of this species.</p>Published as part of <i>Borkent, Art & Grafe, Ulmar, 2012, The Frog-Biting Midges of Borneo — From Two to Eleven Species (Corethrellidae: Diptera), pp. 1-45 in Zootaxa 3279</i> on pages 10-11, DOI: <a href="http://zenodo.org/record/210864">10.5281/zenodo.210864</a>
Enhancement of K+ conductance improves in vitro the contraction force of skeletal muscle in hypokalemic periodic paralysis
No full textAn abnormal ratio between Na+ and K+ conductances seems to be the cause for the depolarization and paralysis of skeletal muscle in primary hypokalemic periodic paralysis. Recently we have shown that the k+ channel opener cromakalim hyperpolarizes mammalian skeletal muscle fibers. Now we have studied the effects of this drug on the twitch force of muscle biopsies from normal and diseased human skeletal muscle. Cromakalim had little effect on the twitch force of normal muscle whereas it strongly improved the contraction force of fibers from patients suffering from hypokalemic periodic paralysis. Recordings of intracellular K+ and Cl- activities in human muscle and isolated rat soleus muscle support the view that cromakalim enhances the membrane K+ conductance (gK+). These data indicate that K+ channel openers may have a beneficial effect in primary hypokalemic periodic paralysis
Ideabuilding, Occupation and construction: Christoph Grafe in a conversation with Stephen Bates and Jonathan Sergison / Ideebouwen, bewoning en constructie: Christoph Grafe in gesprek met Stephen Bates en Jonathan Sergison
No full textArchitectureArchitectur
Acht jaar na Nine+One: Een gesprek tussen Mark Linnemann, Matthijs Bouw, Mechtild Stuhlmacher, en Christoph Grafe / Eight years after Nine+One: a conversation between Mark Linnemann, Matthijs Bouw, Mechtild Stuhlmacher and Christoph Grafe
No full textIn 1997 lanceerde Kristin Feireiss, de toenmalige directrice van het Nederlands Architectuurinstituut (NAi) een tentoonstellingenreeks over toen jonge architectenbureaus onder de titel 'Nine+One'. In haar voorwoord voor de catalogus zette Feireiss haar redenen uiteen voor dit initiatief waarmee ze de aandacht wilde opeisen voor een nieuwe generatie architecten in Nederland. Hoe wel de architecten grofweg een generatie vertegenwoordigden en vrijwel allemaal in de jaren tachtig aan de Technische Universiteit Delft waren opgeleid, was er volgens Feireiss niet sprake van een nieuwe beweging of school, maar van een reeks individuele zoektochten, gevoed door een 'sceptische houding ten opzichte van allesomvattende theorieen' voorbij het 'Modernisme zonder dogma' van een generatie eerder. Ondanks deze nadruk op de verscheidenheid van de agenda's van de afzonderlijke bureaus werd de tentoonstelling (die na de presentaties in het NAi op een reis over de we reid werd gestuurd) vooral gezien als een teken van een tendens en als een presentatie van een nieuwe, frisse, onbevangen en lichtvoetige Nederlandse architectuur, en als zodanig markeerde het publiciteitsinitiatief van de NAi-directrice mogelijk het hoogtepunt van de party van de Nederlandse architectuur van de jaren negentig. Acht jaar later vormt de veranderde situatie van de architectuur en de samenleving in Nederland de achtergrond van een gesprek aan een Amsterdamse eettafel. Zijn de thematieken waarmee jonge Nederlandse architecten zich in de jaren negentig profileerden nog relevant in de context van de gepolariseerde samenleving van na 2001 en 2002? En welke perspectieven openen zich, nu de dynamiek van de hoogconjunctuur verdwenen is?ArchitectureArchitectur
Atlantic trade and regional specialisation in nothern Spain 1550-1650: an integrated trade theory-institutional organisation approach
No full textBased on an in-depth study of the northern Spanish economy in the sixteenth and seventeenth centuries, this paper argues that commercial expansion was a major source of the diverging performance of European regions. It develops an approach that integrates insights from more recent trade theory with those from new institutional economics. New trade theory informs the analysis of changes at a macro-level - defined as traded quantities, the structure of (inter-) regional integration and specialisation, and the larger institutional framework. New institutional economics are the basis for the interpretation of developments at a micro-level defined as the strategies of merchant organisations and individual firms within that larger framework. The paper shows how macro-level changes impacted upon - and interacted with - micro-level structures and processes of adaptation. The integration of quantitative and qualitative analysis demonstrates that the Commercial Revolution transformed the European economy more through structural change than through increased availability of goods
Activity-dependent excitability changes in normal and demyelinated rat spinal root axons
No full textMyelinated nerve fibres with a reduced safety factor for conduction due to demyelination are easily blocked by trains of impulses. To find out why, in vivo recordings from rat ventral root fibres demyelinated with diphtheria toxin have been supplemented with in vivo and in vitro recordings from normal fibres. Despite a small rise in extracellular potassium activity, normal fibres were invariably hyperpolarized by intermittent trains of impulses. This hyperpolarization resulted in an increase in threshold and also in an enhancement of the depolarizing after-potential and the superexcitable period. Replacement of NaCl in the extracellular solution by LiCl completely blocked both the membrane hyperpolarization and the threshold increase which were normally observed during intermittent trains of impulses. At demyelinated nodes which were blocked by trains of impulses (10-50 Hz), conduction block was preceded by a rise in threshold current and in an increase in internodal conduction time, but by no detectable reduction in the outward current generated by the preceding node. It was found possible to prevent the threshold from changing during a train by automatic adjustment of a d.c. polarizing current. This 'threshold clamp' prevented the conduction failure and virtually abolished the changes in internodal conduction time. The threshold changes were attributed to hyperpolarization, as in normal fibres, since (a) the polarizing current required to prevent them was always a depolarizing current, and (b) they were accompanied by an increase in superexcitability. The post-tetanic depression that can follow continuous trains of impulses was attributed to the combination of increased threshold and enhanced superexcitable period due to hyperpolarization. It is concluded that the susceptibility of these demyelinated fibres to impulse trains is not due to a membrane depolarization induced by extracellular potassium accumulation but to a membrane hyperpolarization as a consequence of electrogenic sodium pumping
An intracellular analysis of gamma-aminobutyric-acid-associated ion movements in rat sympathetic neurones
No full textDouble-barrelled ion-sensitive micro-electrodes were used to measure the changes of the intracellular activities of Cl-, K+, and Na+ (aiCl, aiK, aiNa) in neurones of isolated rat sympathetic ganglia during the action of gamma-aminobutyric acid (GABA). The membrane potential of some of the neurones was manually 'voltage clamped' by passing current through the reference barrel of the ion-sensitive micro-electrode. This enabled us to convert the normal depolarizing action of GABA into a hyperpolarization. A GABA-induced membrane depolarization was accompanied by a decrease of aiCl, aiK and no change in aiNa, whereas a GABA-induced membrane hyperpolarization resulted in an increase of aiCl, aiK and also no change in aiNa. GABA did not change the free intracellular Ca2+ concentration, as measured with a Ca2+-sensitive micro-electrode, whereas such an effect was seen during the action of carbachol. pH-sensitive electrodes, on the other hand, revealed a small GABA-induced extracellular acidification. The inward pumping of Cl- following the normal, depolarizing action of GABA required the presence of extracellular K+ as well as Na+, whereas CO2/HCO3--free solutions did not influence the uptake process. Furosemide, but not DIDS, blocked the inward pumping of Cl-. In conclusion, our data show that only changes in intracellular activities of K+ and Cl- are associated with the action of GABA. Furthermore, they indicate that a K+/Cl- co-transport, and not a Cl-/HCO3- counter-transport, may be involved in the homoeostatic mechanism which operates to restore the normal transmembrane Cl- distribution after the action of GABA
Function and distribution of three types of rectifying channel in rat spinal root myelinated axons
No full text1. The nature, distribution and function of rectifying channels in rat spinal root myelinated axons has been assessed with selective blocking agents and a variety of intracellular and extracellular recording techniques. 2. The electrotonic responses of roots poisoned with tetrodotoxin (TTX) to constant current pulses had fast (rise time much less than 1 ms) and slow components, which were interpreted in terms of Barrett & Barrett's (1982) revised cable model for myelinated nerve. Depolarization evoked a rapid outward rectification (time constant, tau approximately 0.5 ms), selectively blocked by 4-aminopyridine (4AP, 1 mM), and a slow outward rectification (tau approximately 15 ms), selectively blocked by tetraethylammonium (TEA, 1 mM) or Ba2+ (0.5 mM). Hyperpolarization evoked an even slower inward rectification, selectively blocked by Cs+ (3 mM) but not by Ba2+. 3. From the different effects of the blocking agents on the fast and slow components of electrotonus, it was deduced (a) that the inward rectification is a property of the internodal axon, (b) that the slow outward rectifier is present at the nodes, and probably the internodes as well, and (c) that the 4AP-sensitive channels have a minor nodal and a major internodal representation. 4. TEA and Ba2+ reduced the accommodation of roots and fibres not poisoned with TTX to long current pulses, whereas 4AP facilitated short bursts of impulses in response to a single brief stimulus. 5. TEA and Ba2+ also abolished a late hyperpolarizing after-potential (peaking at 20-80 ms), while 4AP enhanced the depolarizing after-potential in normal fibres, and abolished an early hyperpolarizing after-potential (peaking at 1-3 ms) in depolarized fibres. Corresponding to the later after-potentials were post-spike changes in excitability and conduction velocity, which were affected similarly by the blocking agents. Cs+ increased the post-tetanic depression attributable to electrogenic hyperpolarization. 6. The physiological roles of the three different rectifying conductances are discussed. It is also argued that the prominent ohmic 'leak conductance', usually ascribed to the nodal axon, must arise in an extracellular pathway in series with the rectifying internodal axon
Langage, objets enseignés et travail enseignant en didactique du français, 17-18 mai 2005, LIDILEM - Université Stendhal Grenoble 3 / GRAFE - Université de Genève -FPSE
No full textLangage, objets enseignés et travail enseignant en didactique du français, 17-18 mai 2005, LIDILEM - Université Stendhal Grenoble 3 / GRAFE - Université de Genève -FPSE . In: La Lettre de l'AIRDF, n°35, 2004/2. p. 70
Langage, objets enseignés et travail enseignant en didactique du français, 17-18 mai 2005, LIDILEM - Université Stendhal Grenoble 3 / GRAFE - Université de Genève -FPSE
No full textLangage, objets enseignés et travail enseignant en didactique du français, 17-18 mai 2005, LIDILEM - Université Stendhal Grenoble 3 / GRAFE - Université de Genève -FPSE . In: La Lettre de l'AIRDF, n°35, 2004/2. p. 70
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