130,673 research outputs found
Psammothidium nivale Potapova & Enache 2013, sp. nov.
No full textPsammothidium nivale Potapova & Enache sp. nov. (Figs 22–31, 45–48) Valvae ellipticae, 5.6–6 µm latae, 11.7–15 µm longae. Raphovalva cum area axialis linearis, area centralis transapicalem rectagularis vel ovalis, 2/3 valvae lata. Raphe recta cum poris proximales paene expansae, in sulci, cum terminis distales simplices. Araphovalva cum area axialis ad apicem angusta, versus centro expansa, rhombico-lanceolata, 2/3 valvae lata. Striae transapicales paulo radiatae, 26–28 in 10 µm in araphovalva, 30–32 in 10 µm in raphovalva. Valves elliptical, 5.6–6 µm wide and 11.7–15 µm long. Raphe valve with linear axial area, central area transapically rectangular to oval occupying 2/3 of the valve breadth. Raphe with proximal pores slightly expanded, located in grooves, and with simple distal endings (Figs 23, 25, 27, 28). Rapheless valve with axial area narrow at apices and widening towards valve centre in a rhombic-lanceolate shape, occupying 2/3 of the valve breadth (Figs 22, 24, 26, 29, 30). Striae slightly radiate, 26–28 in 10 µm on rapheless valve, 30–32 on raphe valve. Type:— USA. Washington: Cascade Mountains, Snow Lake, 46.7576° N, 121.6982468° W, lake sediment (2–2.5-cm depth core interval; lake maximum depth 9.75 m), collected 07 October 2009, collection WACA019, (Circled specimen (Figs 22, 23) on slide GC64864, accession # GC64864 (ANSP!), holotype, designated here; circled specimens on slide GC64865 (ANSP!) and slide 84224 (CANA!), isotypes, designated here). Etymology:—specific epithet refers to the name of the lake (Snow Lake) from where the species was found and described. Psammothidium nivale is distinguished from other Psammothidium species by characteristic coarser striae and areolae on rapheless valve compared to raphe valve. The linear axial area on raphe valves widens slightly near the valve center, and the transapically rectangular to oval central area is bounded by 4–5 shortened striae. External proximal raphe endings are located in grooves, which gradually widen toward valve center. External distal raphe endings are drop-shaped and do not extend beyond the last stria (Fig. 45). Characteristic coarse areolae on rapheless valves have the appearance of transapically elongated slits in SEM (Figs 47–48). In the SEM, the shape of the areolae—transapically elongate—resemble those of P. subatomoides in SEM. However, P. nivale is distinguished from the latter species by all other valve characteristics: more elongated shape of the valve and larger size, shape of central area on both raphe and rapheless valve and clear dimorphism of raphe and rapheless valve in striae density and areolae size. P.nivale was found in Snow Lake and Hidden Lake NOCA in very low abundance (<0.25% relative abundance).Published as part of Enache, Mihaela D., Potapova, Marina, Sheibley, Rich & Moran, Patrick, 2013, Three new Psammothidium species from lakes of Olympic and Cascade Mountains in Washington State, USA, pp. 49-57 in Phytotaxa 127 (1) on page 54, DOI: 10.11646/phytotaxa.127.1.8, http://zenodo.org/record/508546
Psammothidium alpinum Potapova & Enache 2013, sp. nov.
No full text<i>Psammothidium alpinum</i> Potapova & Enache <i>sp. nov</i>. (Figs 9–21, 40–44) <p> <i>Valvae linearae ellipticae, ovalis, 6.3–9.1 µm latae, 14.6–30 µm longae. Raphovalva cum area axialis angusta linearis versus, area centralis rectagularis. Raphe recta poris centralibus unciformis, termini distale punctiformis. Araphovalva cum area axialis angusta, area centralis circularis, irregularis, 1/2 valvae lata. Striae transapicales paulo radiatae, 22–25 in 10 µm cum striae breviores intercalares. Areolae rotundae, grossae, 25 in 10 µm.</i></p> <p>Valves linear-elliptic to oval, 6.3–9.1 µm wide, 14.6–30 µm long. Raphe valve with narrow linear axial area and rectangular-irregular central area. Raphe straight with hook-like proximal pores, drop-shaped distal endings (Figs 10, 11, 13, 15, 16, 20). Rapheless valve with narrow axial area, irregular, rounded central area, occupying about ½ of valve breadth (Figs 9, 12, 14, 17–19, 21). Transapical striae slightly radiate, 22–25 in 10 µm, with shortened marginal striae present (figs 41, 43). Areolae coarse, round, 25 in 10 µm (Fig. 44).</p> <p> <b>Type:—</b> USA. Washington: Cascade Mountains, Snow Lake, 46.7576° N, 121.6982468° W, lake sediment (2–2.5-cm depth core interval; lake maximum depth 9.75 m), collected 07 October 2009, collection <i>WACA019</i>, (Circled specimen (Figs 9, 10) on slide <i>GC64862, accession # GC64862</i> (ANSP!), <b>holotype, designated here</b>; circled specimens on slide <i>GC64863</i> (ANSP!) and slide <i>84223</i> (CANA!), <b>isotypes, designated here</b>).</p> <p> <b>Etymology:</b> —specific epithet refers to the occurrence of the new species in alpine, high elevation lakes.</p> <p> <i>Psammothidium alpinum</i> is similar to <i>P. bioretii</i> (Germain 1957: 85) Bukhtiyarova et Round (1996: 9) in valve size and possession of relatively coarse areolae. It differs from <i>P. bioretii</i> by having more elongate, linear-elliptical valve shape with nearly parallel sides, and a straight central sternum (versus diagonal in <i>P. bioretii</i>). In SEM (Figs 40–44), <i>P. alpinum</i> displays a characteristic doublet of smaller areolae at the valve/ mantle junction and around the mantle (Figs 40, 42). On raphe valves, the central area nearly reaches the valve margin and is bounded by 4–8 short striae. The raphe has characteristic hook-like widely spaced proximal endings (Fig 40) that deflect in the same direction externally (Fig. 40) and opposite internally (Fig. 41). While <i>P. bioretii</i> has terminal raphe fissures curved to opposite sides, <i>P. alpinum</i> lacks terminal fissures, and distal external raphe endings are drop-shaped and do not expand beyond the last stria (Fig. 41). Similar to <i>P. bioretii</i>, <i>P. alpinum</i> has coarse, round areolae visible in LM; a row of coarser areolae border the sternum and central area in LM (Figs 10, 11) and a double row of finer areolae bordering the valve face-mantle junction is visible in SEM (Figs 40, 42). Short intercalary striae are present along the valve margin and expand on the mantle (Figs 41, 43). <i>Psammothidium alpinum</i> has similar valve shape as <i>P. chlidanos</i> (Hohn et Hellerman 1963: 273) Lange-Bertalot (1999: 285) but it can be easily distinguished by its coarser striae and areolae visible in LM.</p> <p> <i>P</i>. <i>alpinum</i> was present in Hidden Lake NOCA (bottom sample, 2% relative abundance) and very rare in top samples from Snow and Stiletto lakes.</p>Published as part of <i>Enache, Mihaela D., Potapova, Marina, Sheibley, Rich & Moran, Patrick, 2013, Three new Psammothidium species from lakes of Olympic and Cascade Mountains in Washington State, USA, pp. 49-57 in Phytotaxa 127 (1)</i> on page 53, DOI: 10.11646/phytotaxa.127.1.8, <a href="http://zenodo.org/record/5085461">http://zenodo.org/record/5085461</a>
Psammothidium lacustre Enache & Potapova & Sheibley & Moran 2013, sp. nov.
No full text<i>Psammothidium lacustre</i> Enache & Potapova <i>sp. nov</i>. (Figs 1–8, 35–39) <p> <i>Valvae lanceolate, 8.4–11.2 µm latae, 16.7–28 µm longae. Raphovalva cum area axialis linearis versus centro expanso, area centralis rectangularis, ½ vel 2/3 valvae lata. Raphe recta poris centralibus simples cum cristae et sulci, interne paulo curvatae. Fissuris terminalibus simplex, longae, ad versum curvatae. Araphovalva cum area axialis angusta, area centralis circulare, 2/3 valvae lata. Striae transapicales radiatae 22–26 in 10 µm; areolae cum foramina externae circulares, foramina internae transapicalem elongatae, 40–60 in 10 µm.</i></p> <p>Valves lanceolate, 8.4–11.2 µm wide, 16.7–28 µm long. Raphe valve with linear axial area, rectangular central area, occupying ½ to 2/3 of valve breadth (Figs 2, 3, 6, 7). Proximal raphe endings slightly deflected internally (Fig. 36). Terminal raphe fissures simple, long, deflected in opposite directions (Figs 2, 3, 6). Rapheless valve with narrow axial area, round central area occupying 2/3 of the valve breadth (Figs 1, 4, 5, 8). Striae radiate, 22–26 in 10 µm; areolae 40–60 in 10 µm, with round external foramina, and internal openings elongated transapically on both valves (Figs 35–39).</p> <p> <b>Type:—</b> USA. Washington: Cascade Mountains, Snow Lake, 46.7576° N, 121.6982468° W, lake sediment (2–2.5-cm depth core interval; lake maximum depth 9.75 m), collected 07 October 2009, collection <i>WACA019</i>, (Circled specimen (Figs 1, 2) on slide <i>GC64860</i>, <i>accession # GC64860</i> (ANSP!), <b>holotype, designated here</b>; circled specimens on slide <i>GC64861</i> (ANSP!) and slide <i>84222</i> (CANA!), <b>isotypes, designated here</b>).</p> <p> <b>Etymology</b>:—specific epithet refers to the occurrence of the new species in a lacustrine environment.</p> <p> The species with the closest morphological features to <i>Psammothidium lacustre</i> is <i>P. helveticum</i> (Figs 32– 34). <i>Psammothidium lacustre</i> has much larger size, with valve width greather than 8 µm, and more acute valve ends compared to <i>P. helveticum</i>. SEM investigations (Figs 35–39) revealed that the proximal raphe endings are internally slightly deflected in opposite directions (Fig. 36), similarly to <i>P. helveticum</i> (see Bukhtiyarova & Round 1996, figure 23). The striae extend uninterrupted onto the mantle, and short striae are present near the central area and occasionally in other parts of valve margin (Fig. 38). Areolae have round external foramina and transapically elongated internal openings (Figs 37, 39).</p> <p> The shape of the axial and central areas on rapheless valves is similar in <i>Psammothidium lacustre</i> and <i>P. helveticum</i>, except that the central area is narrower in <i>P. helveticum</i>. Internally, the shape of areolae is also different: elongated with rims and grooves in <i>P</i>. <i>lacustre</i> versus round or rectangular in <i>P. helveticum</i> (see Bukhtiyarova & Round 1996, figure 23). In LM, <i>P. lacustre</i> is relatively easy to separate from <i>P. helveticum</i>; <i>P. lacustre</i> is larger, has more lanceolate shape, and coarser striae (22–24 versus 23–28) and areolae. <i>Psammothidium lacustre</i> was rare in study lakes (<1% relative abundance).</p>Published as part of <i>Enache, Mihaela D., Potapova, Marina, Sheibley, Rich & Moran, Patrick, 2013, Three new Psammothidium species from lakes of Olympic and Cascade Mountains in Washington State, USA, pp. 49-57 in Phytotaxa 127 (1)</i> on pages 51-53, DOI: 10.11646/phytotaxa.127.1.8, <a href="http://zenodo.org/record/5085461">http://zenodo.org/record/5085461</a>
Three new Psammothidium species from lakes of Olympic and Cascade Mountains in Washington State, USA
No full textEnache, Mihaela D., Potapova, Marina, Sheibley, Rich, Moran, Patrick (2013): Three new Psammothidium species from lakes of Olympic and Cascade Mountains in Washington State, USA. Phytotaxa 127 (1): 49-57, DOI: 10.11646/phytotaxa.127.1.8, URL: http://dx.doi.org/10.11646/phytotaxa.127.1.
FIGURES 22–34 in Three new Psammothidium species from lakes of Olympic and Cascade Mountains in Washington State, USA
No full textFIGURES 22–34: LM micrographs of Psammothidium species from Snow Lake, Washington Cascades. Figs 22–31. Psammothidium nivale sp. nov. Figs 22–23. Holotype specimen, slide ANSP GC64684. Figs 32–34. Psammothidium helveticum. Scale bar = 10 µm.Published as part of Enache, Mihaela D., Potapova, Marina, Sheibley, Rich & Moran, Patrick, 2013, Three new Psammothidium species from lakes of Olympic and Cascade Mountains in Washington State, USA, pp. 49-57 in Phytotaxa 127 (1) on page 54, DOI: 10.11646/phytotaxa.127.1.8, http://zenodo.org/record/508546
FIGURES 45–48 in Three new Psammothidium species from lakes of Olympic and Cascade Mountains in Washington State, USA
No full textFIGURES 45–48: Psammothidium nivale sp. nov., SEM. Figs 45–47. Type material, sample ANSP WACA019, Snow Lake. Fig. 45. External view of raphe valve. Fig. 46. Internal view of raphe valve. Fig. 47. External view of rapheless valve. Fig. 48. External view of rapheless valve, Hidden Lake NOCA, sample ANSP WACA018. Scale bars = 1 µm.Published as part of Enache, Mihaela D., Potapova, Marina, Sheibley, Rich & Moran, Patrick, 2013, Three new Psammothidium species from lakes of Olympic and Cascade Mountains in Washington State, USA, pp. 49-57 in Phytotaxa 127 (1) on page 56, DOI: 10.11646/phytotaxa.127.1.8, http://zenodo.org/record/508546
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Depression in Alzheimer's disease : biomarkers and treatment
No full textDepression and Alzheimer’s disease (AD) are among the most common clinical diagnosis in older people. The relation between depression and AD is complex: depression has been shown to be a risk factor, prodromal symptom and a consequence of AD. Increased understanding of the underlying mechanisms of depression in AD may lead to early detection and differential diagnosis, and is crucial for development of novel and mechanism-based treatments.The first two studies of this doctoral thesis are exploring the associations between depressive symptoms and biomarkers of amyloid deposition and neuronal injury in patients with subjective cognitive impairment (SCI), mild cognitive impairment (MCI) and AD. The aims of the third study were to describe the use of antidepressants in patients with dementia and to explore the association between mortality risk and the use of antidepressants 3 years before the dementia diagnosis.CAIDE Dementia Risk Score is taking into account midlife risk and protective factors; age, educational level, gender, systolic blood pressure, body mass index, cholesterol level and physical activity and APOE genotyping, and can predict dementia over 20 years. The last study was focused on exploring the associations between CAIDE Dementia Risk Score and biomarkers of amyloid deposition, neuronal injury and small vessel pathology in SCI and MCI patients. Additionally we explored the capacity of CAIDE Dementia Risk Score to predict dementia in a memory clinic population.Data were obtained from Memory Clinic Karolinska University Hospital Huddinge Sweden (Study I, II and IV). In study III, two large national registries were merged: the Swedish Dementia Registry (SveDem) and the Swedish Prescribed Drug Register.In study I, analysis of the three different cerebrospinal fluid biomarkers; amyloid beta (CSF Aβ), total-tau (CSF t-tau), and phosphorylated-tau did not support the hypothesis that more severe amyloid or tau pathologies are associated with more severe depressive symptoms. In contrast, SCI and AD patients with depressive symptoms tended to have lower CSF p-tau levels and, in particular, lower CSF t-tau levels than those without depression, indicating less severe neuronal injury. In study II, we used two different analysis methods of MRI to measure medial temporal lobe atrophy and hippocampus volume. Using manual tracing of the hippocampi we found smaller left hippocampus volume in SCI patients with depressive symptoms compared to those without depressive symptoms. In contrast, AD patients with depressive symptoms had less medial temporal lobe atrophy compared with those without depressive symptoms.In study III, 20,050 patients with incident dementia diagnosed in memory clinics and registered in SveDem were included. Information on the total number of medication and all antidepressants dispensed at the time of dementia diagnosis and at the first, the second and the third year prior to dementia diagnosis was obtained from the Swedish Prescribed Drug Register. During a median follow up of 2 years, 5168 (25.8%) dementia patients died. At the time of dementia diagnosis, 5,004 (25.0%) patients were on antidepressant treatment. Use of antidepressant treatment for 3 consecutive years prior to a dementia diagnosis was associated with a lower mortality risk for all dementia disorders in general and particularly in AD.In study IV, a higher CAIDE Dementia Risk Score was associated with higher CSF t-tau levels, more severe medial temporal lobe atrophy and more severe white matter changes. For the CAIDE score including APOE, a score above 9 points was associated with lower CSF Aβ, more severe medial temporal lobe atrophy and more severe white matter changes. CAIDE Dementia Risk Score (version with APOE) performed better at predicting AD compared with CAIDE Dementia Risk Score without APOE.Conclusion: We found that depressive symptoms in patients with AD and SCI are not associated with more amyloid deposition nor more neuronal injury compared with AD and SCI patients without depressive symptoms. Thus our results are consistent with the hypothesis that the mechanisms underlying depression differ between older people with and without AD. Our results have shown that use of antidepressants in prodromal AD stages is associated with a lower mortality risk. Further longitudinal studies are needed to better understand the associations between the use of antidepressants and mortality risk in dementia.List of scientific papersI. Kramberger MG, Jelic V, Kareholt I, Enache D, Eriksdotter Jönhagen M, Winblad B, Aarsland D. Cerebrospinal Fluid Alzheimer Markers in Depressed Elderly Subjects with and without Alzheimer's Disease. Dement Geriatr Cogn Dis Extra. 2012, 2:48-56. https://doi.org/10.1159/000334644 II. Enache D, Cavallin L, Lindberg O, Farahmand B, Kramberger MG, Westman E, Jelic V, Eriksdotter M, Ballard C, Winblad B, Wahlund L-O, Aarsland D. Medial Temporal Lobe Atrophy and Depressive Symptoms in Elderly Patients With and Without Alzheimer Disease. Journal of Geriatric Psychiatry and Neurology 2015, 28:40-8. https://doi.org/10.1177/0891988714541873 III. Enache D, Fereshtehnejad SM, Cermakova P, Garcia-Ptacek S, Kåreholt I, Johnell K, Religa D, Jelic V, Winblad B, Ballard C, Aarsland D, Fastbom J, Eriksdotter M. Antidepressants and mortality risk in a dementia cohort- data from SveDem, the Swedish Dementia Registry. [Submitted]IV. Enache D, Solomon A, Cavallin L, Kåreholt I, Kramberger MG, Aarslad D, Kivipelto M, Eriksdotter M, Winblad B, Jelic V. CAIDE Dementia Risk Score and biomarkers of neurodegeneration in memory clinic patients without dementia. [Submitted]</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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