1,223 research outputs found
Broadening the role of theory in mathematics education research
No full textIn C. Bergsten, E. Jablonka and T. Wedege (Eds), Mathematics and mathematics education: Cultural and social dimensions. Proceedings of MADIF7, The Seventh Mathematics Education Research Seminar, Stockholm, January 26-27, 2010. Linköping: SMDF
Incoltorrida zahamena Perkins & Bergsten 2019, new species
No full textIncoltorrida zahamena, new species Figs. 11 (habitus); 12 (genitalia); 36 (map); 50, 51 (habitat) Type Material. Holotype (male): Madagascar: Toamasina: Alaotra-Mangoro: Zahamena National Park, Antanandava Sect., midaltitude rainforest: Manambato river ~ 100m downstream of Camp Cascade, hygropetric rocks at night, 17.5438S, 48.7230E, 1280m, 10.III.2018, MAD 18-111, Leg. J. Bergsten & T. Ranarilalatiana (NHRS). Paratypes, same data as holotype (2 females NHRS, BMNH). Differential Diagnosis. Differentiated from other members of the genus by the combination of small size (ca. 1.97 mm), oval habitus (Fig. 11), pronotum without median longitudinal ridge, and elytron with eight costae. The elytral series are irregular, giving the elytra a scabrous appearance. Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.97/1.19; head width 0.39; pronotum 0.43/0.92; elytra 1.21/1.19. Dorsum dark brown to black, venter reddish brown, legs reddish brown except femoral-tibial articulations and tarsi dark brown. Sides of frontoclypeal shield slightly arcuate. Clypeus about as long as frons. Pronotum with short oblique carinae on anterior 1/3 moderately developed, no indication of midlongitudinal carina, area posterior to carinae transversely rounded, with no indication of ridges or depressions. Cuticle rough, subgranulate. Elytron with eight costae of varying height; costa #6 very low and short, costa #8 generally higher and stronger than other costae; transverse ridges between costae absent or very indistinct. Serial punctures large and coarse, producing scabrous appearance. Metaventral tabella with very faint, indistinct transverse grooves; midlongitudinal groove in posterior 1/2 of metaventral tabella widest at about midlength. Midlongitudinal carina of first abdominal ventrite strong and extends length of ventrite. Male genitalia in lateral view distinctively thickened in basal 1/2, apical 1/2 narrowing, with tip slightly widened and spinose (Fig. 12). Etymology. Named in reference to the type locality.Published as part of Perkins, Philip D. & Bergsten, Johannes, 2019, New Myxophagan water beetles from Madagascar (Coleoptera: Torridincolidae, Hydroscaphidae), pp. 57-96 in Zootaxa 4657 (1) on pages 76-80, DOI: 10.11646/zootaxa.4657.1.2, http://zenodo.org/record/336980
Incoltorrida quintacostata Perkins & Bergsten 2019, new species
No full textIncoltorrida quintacostata, new species Figs. 2, 7 (habitus), 17, 18 (genitalia), 23 (larva), 34 (map), 42, 43 (habitat), Type Material. Holotype (male): Fianarantsoa, 3.5km N Ivato, 20º 35.844’ S 47º 12.78’ E, rock face seep beside hwy. 7, elev. 1471 m, 5 xi 2014, P. D. Perkins (NHRS). Paratypes (193): Same data as holotype (19: NHRS, MCZ); Antsiranana, Anjiabe Ambony: Ambilobe: Antsabe stairways-like cascade with vertical (!) steps, exposed, extremely hot day, N: -13.60930 E: 48.72120, elev. 303 m, 23 xi 2004, Balke et al. (P25 MD16) (8 BMNH; 2 DNA extractions, #’s BMNH 670734, BMNH 670735); Diana: Antsaba: Galoko mountains, 3.4 km NW from Anstaba, S13.60931 E48.72129, aspirator, forceps, sieves: hygropetric rocks and pools, elev. 296 m, 28 xi 2012, elev. 296 m, 28 xi 2012, J. Bergsten, R. Bukontaite, J.H. Randriamihaja & T. Ranarilalatiana (MAD12-31) (5 NHRS); Diana: Antsaba: Galoko mountains, S13.60974 E48.72175, sieves and aspirator: hygropetric rocks and water pools, elev. 263 m, 25 xi 2012, J. Bergsten, R. Bukontaite, J.H. Randriamihaja & T. Ranarilalatiana (MAD12-26) (62 NHRS, BMNH, PBZT / MBC); Fianarantsoa, 3.2km S Ambohimanjaka, 20º 14.0343’ S 47º 5.59145’ E, waterfall and hygropetric habitat near hwy. 7, elev. 1415 m, 5 xi 2014, P. D. Perkins (95 NHRS & MCZ); Atsimo Antsinanana: R.S. Manombo: Parcelle I, Rearatra, Piste 56: S23.006183 E47.7338833, GB nets and sieves, forest stream with pools, elev. 21 m, 14 xii 2013, J.H. Randriamihaja & T. Ranarilalatiana (MAD13- 73) (3 NHRS); 20.7722S 47.1809E; Amoron’i Mania, 3km south of Ambalamanakana next to RN7, Ankazomivady forest, hygropetric rocks and marsh with vegetation, elev. 1700 m, 1 xi 2014, J. Bergsten, T. Ranarilalatiana & S. Holmgren (MAD 14-02) (1 NHRS). Differential Diagnosis. Differentiated from all other known Incoltorrida, except I. galoko, by the elytral sculpture. Each elytron has only five costae: #1, #2, #3, #5, and #8; costa #4, #6, and #7, which are present in other species, are absent in I. quintacostata (Fig. 2). The serial punctures are minute and very indistinct (microslide preparation necessary to see the punctures clearly). In this species the elytral costae are well developed in height, but comparatively narrow; the areas between the costae are quite flat. The transverse ridge that connects elytral costae #5 and #8 is more or less distinct (depending on the population). The anterior depressions of the pronotum are well developed and the foveae forming the medial margins of the ridges are narrowly separated and the intervening surface is transversely rounded, but there is no separate median carina. The pronotal sculpture and adult size of I quintacostata differ markedly from those of I. galoko, which also has five costae of each elytron. The ridges and impressions of the pronotum are similar to those of I. benesculpta, a much smaller species that has very different elytral sculpture; the aedeagi of the two species markedly differ (Figs. 18, 20). Description. Size: holotype (length/width, mm): body (length to elytral apices) 2.33/1.32; head width 0.47; pronotum 0.51/0.93, elytra 1.50/1.32. Dorsum dark brown to black, venter brown to dark brown, legs brown except femoral-tibial articulations and tarsi black. Sides of frontoclypeal shield very slightly arcuate, almost parallel-sided, and only very slightly and gradually narrowed from frons vertex to the transverse anterior margin of the clypeus. Short oblique carinae on anterior 1/3 of pronotum are well developed; no indication of a midlongitudinal carina. Basal 1/3 of pronotum with distinctive carina on each side, each slightly oblique toward midline. Each elytron with only five costae: #1, #2, #3, #5, and #8; costae #4, #6, and #7 absent. Areas between costae quite flat, and serial punctures minute, very indistinct, a unilinear row located adjacent to the lateral margin of each costa. Transverse ridge linking costae #5 and #8 present, but more distinctive in some populations than others. Lateral margins of the metaventral tabella straight for most of their length, arcuate only very near base. Midlongitudinal groove in posterior 1/2 of the metaventral tabella is narrow and parallel-sided. Midlongitudinal carina of the first abdominal ventrite is moderately strong but usually does not extend the full length of the ventrite. Male genitalia long and slender (Figs. 17, 18); see remarks. Etymology. Named in reference to the five costae of each elytron. Remarks. Some specimens, such as the holotype, have the posterior angles of the pronotum very weakly shallowly notched; other specimens do not have this weak indentation, and some specimens have it only on one side. The male genitalia in ventral view is long and comparatively slender, with a quite spinose apical tip (Figs. 17, 18). Males vary considerably in body length, ca. 2.09–2.39 mm. The length of the aedeagus varies, roughly, in proportion to the body size; for example: (aedeagus length/body length): 0.73/2.18 (=0.33); 0.75/2.15 (=0.35); 0.77/2.09 (=0.37);0.80/2.24 (=0.36); 0.93/2.39 (=0.39, the holotype). The shape of the aedeagus does not vary significantly. This is the most commonly collected species of Incoltorrida (Fig. 34). Four larvae (NHRS) were collected at the type locality, and 54 larvae (NHRS) were collected at site MAD 12- 26. DNA sequences of partial CO1 (Acc. Nos. FJ819700 (BMNH 670734) and FJ819701 (BMNH 670735)) and partial 28S (FJ 818156 (BMNH 670734) and FJ818157 (BMNH 670735)) published by Monaghan et al (2009) are based on adult specimens, and are available in Genbank.Published as part of Perkins, Philip D. & Bergsten, Johannes, 2019, New Myxophagan water beetles from Madagascar (Coleoptera: Torridincolidae, Hydroscaphidae), pp. 57-96 in Zootaxa 4657 (1) on pages 68-70, DOI: 10.11646/zootaxa.4657.1.2, http://zenodo.org/record/336980
Incoltorrida magna Perkins & Bergsten 2019, new species
No full text<i>Incoltorrida magna</i>, new species <p>Figs. 3, 4, 10 (habitus); 21 (genitalia); 36 (map); 40 (habitat)</p> <p> <b>Type Material.</b> Holotype (male): <b>Antsiranana</b>, Diana: Antsaba: Galoko mountains, 3.4 km NW from Anstaba, S13.60931 E48.72129, aspirator, forceps, sieves: hygropetric rocks and pools, elev. 296 m, 28 xi 2012, elev. 296 m, 28 xi 2012, J. Bergsten, R. Bukontaite, J.H. Randriamihaja & T. Ranarilalatiana (MAD12-31) (NHRS). Paratypes (36): Same data as holotype (1 NHRS); <b>Antsiranana</b>, Anjiabe Ambony: Ambilobe: Antsabe stairways-like cascade with vertical (!) steps, exposed, extremely hot day, N: -13.60930 E: 48.72120, elev. 303 m, 23 xi 2004, Balke <i>et al</i>. (P25 MD16) (35 BMNH, NHRS, MCZ, PBZT / MBC; 2 DNA extractions, #’s BMNH 670732, BMNH 670733).</p> <p> <b>Differential Diagnosis.</b> This is the largest known <i>Incoltorrida</i> species: l/w ca. 2.62/1.58. The elytral serial punctures are very distinct, as is the transverse ridge that links costae #5 and #8. The pronotum lacks the basal ridges seen in <i>I. quintacostata</i>, <i>I. benesculpta</i>, and <i>I. madagassica</i>. It is much larger than <i>I. marojejy</i> (2.62 vs. 2.19); <i>I. marojejy</i> lacks the pronotal midlongitudinal carina that is present in <i>I. magna</i>, and the frons plate is shaped differently in the two species. The male genitalia (Fig. 21) distinctively differ from that of the other species in the genus. See also the diagnosis of <i>I. madagassica</i>.</p> <p> <b>Description</b>. Size: holotype (length/width, mm): body (length to elytral apices) 2.62/1.58; head width 0.50; pronotum 0.55/1.12; elytra 1.78/1.58. Dorsum dark brown to black, venter brown to reddish brown, legs brown to reddish brown except tarsi and femoral-tibial articulations black.</p> <p>Frontoclypeal shield narrowest at anterior 1/3, with sides of frons slightly arcuate; apical 1/3 is slightly wider than area of frontoclypeal suture.</p> <p>Short oblique carinae on anterior 1/3 of pronotum are well developed; a midlongitudinal carina is present, though not as developed as the oblique carinae; the area posterior to the carinae is transversely rounded and shows no indication of ridges or depressions, except for a basal impression in front of scutellum.</p> <p>Elytra quite convex, declivity steep. Each elytron with eight wide and high costae; #4 continuous, not interrupted by punctures; #5 weakly bisinuate; #6 and #7 distinct, though crossed by transverse ridge that connects #5 and #8. Second transverse ridge links #3 and #5, in nearly same plane as the #5-#8 ridge.</p> <p>Posterior 1/2 of metaventral tabella without distinctive, closely spaced transverse grooves; midlongitudinal groove in posterior 1/2 of metaventral tabella narrow and parallel-sided.</p> <p>Midlongitudinal carina of first abdominal ventrite not especially strong and extends only 1/2 length of ventrite.</p> <p>Male genitalia in lateral view distinctively arcuate; in ventral view widest at about apical 1/4, and then narrowed, with tips pointing slightly outward (Fig. 21).</p> <p> <b>Etymology</b>. Named in reference to the relatively large size.</p> <p> <b>Remarks</b>. DNA sequences of partial CO1 (Acc. Nos. FJ819703 (BMNH 670732) and FJ819702 (BMNH 670733)) and partial 28S (FJ 818159 (BMNH 670732) and FJ818158 (BMNH 670733)) published by Monaghan <i>et al.</i> (2009) are based on adult specimens, and are available in Genbank.</p>Published as part of <i>Perkins, Philip D. & Bergsten, Johannes, 2019, New Myxophagan water beetles from Madagascar (Coleoptera: Torridincolidae, Hydroscaphidae), pp. 57-96 in Zootaxa 4657 (1)</i> on page 76, DOI: 10.11646/zootaxa.4657.1.2, <a href="http://zenodo.org/record/3369801">http://zenodo.org/record/3369801</a>
Mitochondrial metabolism reveals a functional architecture in intact islets of Langerhans from normal and diabetic Psammomys obesus
No full textThe cells within the intact islet of Langerhans function as a metabolic syncytium, secreting insulin in a coordinated and oscillatory manner in response to external fuel. With increased glucose, the oscillatory amplitude is enhanced, leading to the hypothesis that cells within the islet are secreting with greater synchronization. Consequently, non-insulin-dependent diabetes mellitus (NIDDM; type 2 diabetes)-induced irregularities in insulin secretion oscillations may be attributed to decreased intercellular coordination. The purpose of the present study was to determine whether the degree of metabolic coordination within the intact islet was enhanced by increased glucose and compromised by NIDDM. Experiments were performed with isolated islets from normal and diabetic Psammomys obesus. Using confocal microscopy and the mitochondrial potentiometric dye rhodamine 123, we measured mitochondrial membrane potential oscillations in individual cells within intact islets. When mitochondrial membrane potential was averaged from all the cells in a single islet, the resultant waveform demonstrated clear sinusoidal oscillations. Cells within islets were heterogeneous in terms of cellular synchronicity (similarity in phase and period), sinusoidal regularity, and frequency of oscillation. Cells within normal islets oscillated with greater synchronicity compared with cells within diabetic islets. The range of oscillatory frequencies was unchanged by glucose or diabetes. Cells within diabetic (but not normal) islets increased oscillatory regularity in response to glucose. These data support the hypothesis that glucose enhances metabolic coupling in normal islets and that the dampening of oscillatory insulin secretion in NIDDM may result from disrupted metabolic coupling. <br/
Optimal breast cancer pathology manifesto
No full textThis manifesto was prepared by a European Breast Cancer (EBC) Council working group and launched at the European Breast Cancer Conference in Glasgow on 20 March 2014. It sets out optimal technical and organisational requirements for a breast cancer pathology service, in the light of concerns about variability and lack of patient-centred focus. It is not a guideline about how pathology services should be performed. It is a call for all in the cancer community - pathologists, oncologists, patient advocates, health administrators and policymakers - to check that services are available that serve the needs of patients in a high quality, timely way
Fig. 3 in The Morphology and Behavior of the Endemic Malagasy Whirligig Beetle Heterogyrus milloti Legros, 1953 (Coleoptera: Gyrinidae: Heterogyrinae)
No full textFig. 3. Antennae of Heterogyrus milloti and Spanglerogyrus albiventris. A) Antenna of H. milloti, box indicates area shown in B, scale bar = 300 µm, B) Antennal apex of H. milloti, s.b. = sensilla basiconicum type, s.c. = sensilla chaetica type, scale bar = 50 µm, C) Most of antennal flagellum of S. albiventris, scale bar = 100 µm.Published as part of Gustafson, Grey T., Bergsten, Johannes, Ranarilalatiana, Tolotra, Randriamihaja, Jacquelin Herisahala & Miller, Kelly B., 2017, The Morphology and Behavior of the Endemic Malagasy Whirligig Beetle Heterogyrus milloti Legros, 1953 (Coleoptera: Gyrinidae: Heterogyrinae), pp. 315-328 in The Coleopterists Bulletin 71 (2) on page 320, DOI: 10.1649/0010-065X-71.2.315, http://zenodo.org/record/536385
Streptococcal and staphylococcal tissue infections : therapeutic challenges and opportunities
No full textStreptococcus pyogenes and Staphylococcus aureus have been leading causes of human infections throughout history. S. pyogenes is of the top-ten pathogens responsible for most death globally, 0.5 million deaths per year. S. aureus is carried asymptomatically by half the population at any point in time and S. aureus bacteremia is probably the most common life-threatening infection worldwide. These bacteria colonize us, cause mild self-limiting infections such as impetigo and pharyngitis but also rare grave conditions such as streptococcal/staphylococcal toxic shock syndrome (STSS) and necrotizing soft tissue infections (NSTI).In STSS, patients are recommended to receive adjunctive intravenous immunoglobulin (IVIG) to dampen the mitogenic superantigen-response in T-lymphocytes. In NSTI, the benefit of IVIG treatment is unclear. The first randomized controlled trial of IVIG in NSTI by all microbiological etiologies showed no benefit, but the subgroup dominated by S. pyogenes and S. aureus infections indicated a trend of improved outcome. Here, we assessed plasma samples from these patients, demonstrating that a dose of 25g IVIG is effective at neutralizing toxins from most S. pyogenes strains. The neutralizing capacity of patient plasma correlated with the IVIG dose administered.In NSTI, the antibiotic treatment recommendations include a -lactam antibiotic such as penicillin, and a toxin-dampening antibiotic such as clindamycin. Using an organotypic 3D model of human skin, we treated S. pyogenes tissue infections with this standard treatment and observed only a minor effect on reduction of bacterial viability. When we added the antibiotic rifampicin as adjunctive treatment, we observed a significant reduction of bacterial viability and metabolism. Bacterial biofilm formation has been recognized as a complicating microbiological feature of S. pyogenes NSTI, and this could be the reason behind the treatment failure and high morbidity and mortality associated with the infections.S. aureus biofilm formation is regulated by the Accessory gene regulator or Agr system. Using an Agr-silent mutant, we measured biofilm formation by methicillin-resistant S. aureus (MRSA). We observed impaired biofilm dispersal in the Agr-silent MRSA strain, resulting in sustained biofilm formation on polystyrene surfaces. When grown on collagen-coated surfaces, biofilm increased by both strains. In our skin tissue model, both isolates formed biofilm, but the Agr-silent strain did not affect the epithelial integrity while the Agr-signaling strain caused epithelial damage and disseminated into the deeper layers of the tissue.Host-pathogen interactions are complicated due to the multitude of cells and molecules involved. In this thesis, we have studied bacterial pathogens in their natural habitat: near human cells. Although not as complex as real tissue, our model systems are relevant by mimicking important features of the clinical setting. Our research questions are clinical, and our setup is experimental.List of scientific papersI. Bergsten, H., M. B. Madsen, F. Bergey, O. Hyldegaard, S. Skrede, P. Arnell, O. Oppegaard, A. Itzek, A. Perner, M. Svensson and A. Norrby-Teglund. Correlation Between Immunoglobulin Dose Administered and Plasma Neutralization of Streptococcal Superantigens in Patients With Necrotizing Soft Tissue Infections. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2020;71(7):1772-5. https://doi.org/10.1093/cid/ciaa022 II. Bergsten, H., L. M. Palma Medina, M. Morgan, K. Moll, D. H. Skutlaberg, S. Skrede, T. Wajima, M. Svensson and A. Norrby-Teglund. Adjunctive Rifampicin Increases Antibiotic Efficacy in Group A Streptococcal Tissue Infection Models. Antimicrobial agents and chemotherapy. 2021;65(11):e0065821. https://doi.org/10.1128/AAC.00658-21 III. Bergsten, H., S. M. Shambat, E. Kvedaraite, M. Svensson and A. Norrby-Teglund. Dysfunctional quorum sensing in a natural AgrC variant results in sustained biofilm by ST22 methicillin-resistant Staphylococcus aureus. [Manuscript]</p
Hovahydrus undetermined
No full textHovahydrus sp. near H. minutissimus (Régimbart, 1903) Source of material. The four instar III larvae studied were associated with adults collected at the following locality: Madagascar: Antsiranana: Sava Marojejy National Park:mid-high altitude rainforest: watersource stream to camp III, 100 m from camp, MAD18-34. 14.4373S, 49.7428E, 1330 m, 11.II.2018. Leg J. Bergsten & T. Ranarilalatiana. Diagnosis (instar III). The instar III larvae of Hovahydrus sp. can easily be distinguished from those of H. praetextus by the following combination of characters: smaller size, HL = 0.71–0.76 mm; head capsule sagittate, frontoclypeus broad, subquadrate apically (Fig. 2); parietale with a reduced number of temporal spines in dorsal view (Fig. 2); metathoracic leg elongate,> 3.00 times HW; femora, tibiae and tarsi with a lesser number of secondary setae (Figs 9–10; Table 2); abdominal segment VIII distinctly constricted at point of insertion of urogomphi (Fig. 11).Published as part of Alarie, Yves, Michat, Mariano C., Ranarilalatiana, Tolotra & Bergsten, Johannes, 2022, Larval morphology of the Madagascan endemic diving beetle genus Hovahydrus Biström, 1982 (Coleoptera: Dytiscidae) and phylogenetic comparison with other known Hyphydrini, pp. 227-246 in Zootaxa 5219 (3) on page 231, DOI: 10.11646/zootaxa.5219.3.
Hovahydrus praetextus HPRA
No full textHovahydrus praetextus (Guignot, 1951) (Figs 13–16) Source of material. The only instar III larva studied was associated with adults collected at the following locality: Madagascar: Antsiranana: Sava Marojejy National Park:alpine, above treeline:small clearwater stream with knee-deep pools, below summit: MAD18-31. 14.4506S, 49.7318E, 2060 m, 10.II.2018. Leg J. Bergsten & T. Ranarilalatiana. Diagnosis (instar III). The instar III larvae of Hovahydrus praetextus can easily be distinguished from those of Hovahydrus sp. by the following combination of characters: larger size, HL = 1.13 mm; head capsule pear-shaped, frontoclypeus narrower, rounded apically (Fig. 13); parietale with a large number of temporal spines in dorsal view (Fig. 13); metathoracic leg shorter, <2.90 times HW; femora, tibiae and tarsi with a larger number of secondary setae (Figs 15–16; Table 2); abdominal segment VIII lightly constricted at point of insertion of urogomphi (Fig. 14).Published as part of Alarie, Yves, Michat, Mariano C., Ranarilalatiana, Tolotra & Bergsten, Johannes, 2022, Larval morphology of the Madagascan endemic diving beetle genus Hovahydrus Biström, 1982 (Coleoptera: Dytiscidae) and phylogenetic comparison with other known Hyphydrini, pp. 227-246 in Zootaxa 5219 (3) on page 232, DOI: 10.11646/zootaxa.5219.3.
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