131,302 research outputs found
Las curvas de oferta y demanda de Fleeming Jenkin
No full textEditada en la Fundación Empresa PúblicaFleeming Jenkin (1833-1885) fuee el primer británico que dibujó curvas de oferta y
demanda, las analizó como fondones matemáticas y las empleo para abordar problemas
económicos. Célebre ingeniero, efectuó notables aportaciones a la economía, que
fueron en su tiempo poco destacadas. Este artículo revisa el pensamiento de Jenkin,
poniendo el énfasis en su análisis de las tres leyes de la oferta y la demanda, y su aplicación
al mercado de trabajo y a los impuestos, que dio lugar al descubnmiento independiente
de la noción de excedente del consumidor y del productor. El articulo sostiene
que una razón por la que Jenkin no obtuvo el reconocimiento que merecía hie el
trato hostil que le dispensaron Jevons y Marshall, que devaluaron sus decucciones e
insistieron en que se le habían anticipado. El artículo concluye que esta reivindicacion
carece de fundamento.Fleeming Jenkin (1833-1885) was die first person in Britain to draw supply and
demand curves, discussing them as mathematical functions and employing them to study economic problems. A celebrated engineer, he made remarkable contributions to economics, that attracted little attention in his time. This article goes through Jenkin's
thought, emphasizing his analysis of the three laws of supply and demand, and its application
to the labour market and the taxes, that produced the independent discovery
of the notion of consumer and producer surplus. The article holds that a reason why
Jenkin lacked the acknowledgement he deserved lay in the hostile attitude towards him
by Jevons and Marshall, who undervalued his contributions and insisted that they had
anticipated Jenkin. The article concludes that this claim is unfounded.Publicad
Jenkin, D K, 4410534
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/395129Surname: JENKIN. Given Name(s) or Initials: D K. Military Service Number or Last Known Location: 4410534. Missing, Wounded and Prisoner of War Enquiry Card Index Number: SEA-3066.228852
Item: [2016.0049.27422] "Jenkin, D K, 4410534
Jenkin-S, D W, 38913
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/395176Surname: JENKIN-S. Given Name(s) or Initials: D W. Military Service Number or Last Known Location: 38913. Missing, Wounded and Prisoner of War Enquiry Card Index Number: SEA-2149.228970
Item: [2016.0049.27469] "Jenkin-S, D W, 38913
Dermatreton Jenkin 1908
No full textGenus Dermatreton Jenkin, 1908 TYPE SPECIES. — Dermatreton hodgsoni Jenkin, 1908 by subsequent designation (this work). DIAGNOSIS. — Sycanthidae with coalescent radial tubes whose distal parts are supported by tangential triactines that form a loose meshwork perforated by large inhalant cavities. DESCRIPTION We use the genus Dermatreton in the manner proposed by Jenkin (1908a). The loose cortex, which covers the distal parts of fused radial tubes, is in the form of a meshwork with broad openings formed by the inhalant spaces. As such it cannot give sufficient mechanical rigidity to the sponge, and consequently the atrial skeleton is thickened and rigid. Jenkin (1908a) has not designated the type species of the genus. Among the originally included species we designate D. hodgsoni as the type species. Similar morphology is observed in Dermatreton (Tenthrenodes) scotti (Fig. 24). The description and illustrations of Dermatreton chartaceum suggest that it should be included in the genus Breitfussia.Published as part of Borojevic, Radovan, Boury-Esnault, Nicole & Vacelet, Jean, 2000, A revision of the supraspecific classification of the subclass Calcaronea (Porifera, class Calcarea), pp. 203-263 in Zoosystema 22 (2) on page 229, DOI: 10.5281/zenodo.539217
Achramorpha nivalis Jenkin 1908
No full textAchramorpha nivalis Jenkin, 1908 (Figs 1 A–H; Table 2) Original description. Jenkin 1908, p. 33, pl. XXVII, figs 7–8, pl. XXXV and XXXVI, figs 105–112. Type locality. Winter Quarters Bay, Antarctic. Synonyms and citations. Achramorpha nivalis Dendy & Row 1913, p. 765; A. nivalis Hôzawa 1918, p. 542; A. nivalis, Brønsted 1931, p. 32; A. nivalis Burton 1963, p. 93, 526 (fig 332). Material examined. Holotype: BMNH-1907.8.6.122 (one section slide), Winter Quarters Bay, Antarctic, collection date 11.11.1902. Paratype: BMNH-1907.8.6.111 (one complete specimen and four slides; see Table 1), Winter Quarters Bay, Antarctic, collection date 29.08.1903. Additional material: BMNH-1907.8.6.119: one slide, National Antarctic Expedition (HMS Discovery), collection date 08.09.1903. BMNH-1907.8.6.122-124: three slides, National Antarctic Expedition (HMS Discovery). BMNH-1907.8.6.125: one slide, National Antarctic Expedition (HMS Discovery), collection date 08.09.1903. BMNH-1907.8.6.128: one slide, National Antarctic Expedition (HMS Discovery), collection date 24.10.1902. BMNH-1907.8.6.129: one slide, National Antarctic Expedition (HMS Discovery), collection date 24.10.1902. BMNH-1926.10.26.49: one slide, British Antarctic Expedition 1910–1913 (Terra Nova). Morphology. Sponge cylindrical, wider at the base and with well-developed oscular fringe at the narrow end (Fig 1A). Surface hispid due to long diactines projecting from the choanosome. Colour light brown in ethanol. Aquiferous skeleton syconoid with elongated choanocyte chambers (Fig 1B). The cotype is 12.95 mm high, 1.87– 2.94 mm wide and 0.61–0.86 mm thick (Fig 1A). Skeleton. The cortical skeleton is made up by triactines positioned tangentially, diactines and microdiactines (Fig 1C). Diactines are very long and protruding, unevenly scattered and can cross through the body wall to the atrial cavity (Fig 1D). Microdiactines are spined and organized around the ostia (Figs 1C, 1F). Choanoskeleton inarticulated and mainly composed of the unpaired actines of the atrial chiactines and by the large diactines (Figs 1B, 1D). Some cortical triactines can be observed in the middle of the choanosome (Fig 1D). The chiactines are oriented perpendicularly to the atrium, with the long paired actines adjacent to the atrial wall and the apical actines projecting into the atrial cavity (Fig 1B). The oscular region is composed of long trichoxeas which form the oscular fringe, and also by thin but large tetractines, which are positioned longitudinally with the unpaired actines pointing towards the base of the sponge (Fig 1E). Spicules. Diactines: long and straight with both ends sharp. Size: 688.4 ± 328.6 µm length, 14.2 ± 8.2 µm width (Figs 1 C–D; Table 2). (*) Most of the diactines were broken. (**) Unpaired actines broken or not completely visible in the slides. (***) Diactines II = Microdiactines. (†) Similar to diactines II but longer. Microdiactines: small with hastate points and minute spines towards the hastate tip, which is slender than the other one. Some of these diactines are slightly curved. Size: 80.4 ± 11.5 µm length, 3.4 ± 0.9 µm width (Figs 1C, 1F; Table 2). Cortical triactines: sagittal with the unpaired actines straight and longer than the paired actines, which are slightly curved upwards forming a round bend. Paired actines of similar length. Size: unpaired actines 230.9 ± 73.1 µm length, 6.7 ± 2 µm width; paired actines 136.6 ± 43.8 µm length, 6.4 ± 2 µm width (Fig 1G; Table 2). There are a few triactines with the paired angle almost straight, which probably are from the oscular region. Chiactines: unpaired actines straight and longer than the paired actines. Apical actine straight and tapering to a sharp tip. Size: unpaired actines 462.1 ± 113.1 µm length, 9.4 ± 1.1 µm width; paired actines 175.2 ± 18.9 µm length, 8.8 ± 1.2 µm width; apical actine 102.5 ± 15.9 µm length, 7.7 ± 1 µm width (Figs 1 B–H; Table 2). Oscular tetractines: the unpaired actines are longer and thinner than the paired actines. The apical actine is curved and pointing towards the osculum. Size: unpaired actines 259.7 ± 65.7 µm length, 9.4 ± 0.6 µm width; paired actines 167 ± 6.1 µm length, 12.7 ± 0.5 µm width; apical actines 49.9 ± 5 µm length, 7.7 ± 1.1 µm width (Table 2). Oscular trichoxeas: it was difficult to measure them in the spicule preparations, but according to Jenkin (1908) they are around 2.5 mm length and 6.0 µm width and minutely hastate at the distal end (Fig 1E). Molecular identification. Not available. Distribution and depth. A. nivalis has been reported from two localities around the Antarctic: Winter Quarters Bay (Jenkin 1908), and Winterstation in Wilkes Land in the East-Antarctic, at 350–385 m depth (Brønsted 1931). Remarks. Jenkin (1908) mentioned that there were 14 specimens of A. nivalis in the collection at the BMNH. However, the material available in the museum collection was only one slide from the holotype, one specimen labelled as cotype and several spicules preparations and histological sections, probably from those specimens mentioned by Jenkin (1908). Following the 4 th edition of the International Code of Zoological Nomenclature (ICZN) the term cotype is not recognize by the Code and should not be used in zoological nomenclature, especially e.g. in the sense of syntype or paratype (recommendation 73E). Therefore, the specimen BMNH-1907.8.6.111 which was labelled as cotype, is now erected as paratype. All the examined slides from different specimens present the same long projecting diactines in the cortical skeleton, but these are shorter than what was reported in the original description (see Table 2), probably due to the fact that most of them were broken. Jenkin (1908) divided the tetractines in two categories according to the size (see Table 2). This may be associated to the position of the spicules in the oscular area, since it has been observed in other Achramorpha spp. that they are smaller the closer they are to the oscular fringe. However, as most tetractines were broken or not easily visible in the sections, we were only able to measure five complete ones. A third type of diactines was mentioned by Jenkin (1908), who described them as “rather longer, small, straight hastate oxea” and of size 120–140 µm long, and 4 µm thick. However, we could not find this type of diactines in the material examined, but according to the figure presented by Jenkin (1908) they look similar to microdiactines, but slightly longer (Table 2).Published as part of Alvizu, Adriana, Xavier, Joana R. & Rapp, Hans Tore, 2019, Description of new chiactine-bearing sponges provides insights into the higher classification of Calcaronea (Porifera: Calcarea), pp. 201-251 in Zootaxa 4615 (2) on pages 206-209, DOI: 10.11646/zootaxa.4615.2.1, http://zenodo.org/record/324463
Leucascus leptoraphis Jenkin 1908
No full textLeucascus leptoraphis (Jenkin, 1908) Diagnosis: Cortical membrane with tripods. Atrial skeleton composed of triactines and tetractines with cylindrical actines. Tetractines are very rare. Synonymies: Leucandra primigenia var. leptoraphis: Jenkin 1908: 14; Leucetta leptoraphis: Burton 1929: 404; Gappa & Landoni 2005: 219. Type material: BMNH 1907.8. 6.65 (Holotype, McMurdo Bay, Antarctica; Discovery Antarctic Expedition). Type locality: McMurdo Bay, Antarctica. Additional analysed material: ZMAPOR 13265 (Turtle Rock, McMurdo Sound, Antarctica; coll. B. Baker; 1997). Description: There is no information about the colour of the holotype in vivo, but the specimen from the ZMA was white. After fixation, both specimens became beige (Figure 5 A). The cormus is digitiform and formed by tightly anastomosed tubes covered by a smooth and thin membrane. The consistency is soft. Only a fragment of the holotype was analysed, but the specimen from the ZMA measures 9.5 x 5.5 x 2.0 cm (Figure 5 A). At the end of each digitiform projection of the cormus there is an apical osculum (diameter of 0.1 to 1.0 cm) surrounded by a delicate membrane. It was not possible to recognize the oscula in the fragment of the holotype. The atrial cavity is wide in the ZMA specimen, but Jenkin (1908) mentioned that in the holotype it was small, however, he did not give measurements. The skeleton is composed of tripods, triactines, and very rare tetractines. The cortical membrane has only tripods (Figures 5 B, C) while the tubes and the atrial membrane have only triactines (Figure 5 D). Consequently, the tubes and the atrium are smooth. Tetractines were not observed in the skeleton preparations of the holotype, and were not mentioned in the original description of the species, however some rare tetractines were found in the spicule slides. Two tetractines were found in the atrial skeleton of the specimen ZMAPOR 13265. Spicules/ Specimens Length (µm) Width (µm) Min Mean SD Max Min Mean SD Max N Tripod BMNH 1907.8. 6.65 (H) 80.2 114.4 25.0 157.9 6.1 7.9 1.5 10.9 12 ZMAPOR 13265 89.9 123.8 14.9 153.1 4.9 7.5 1.6 12.1 30 All specimens 80.2 119.1 4.7 157.9 4.9 7.7 0.2 12.1 – Triactine BMNH 1907.8. 6.65 (H) 128.8 176.3 20.0 206.5 3.6 4.3 0.6 6.0 30 ZMAPOR 13265 97.2 160.6 23.9 189.5 3.6 5.4 0.8 7.3 30 All specimens 97.2 168.4 7.8 206.5 3.6 4.8 0.5 7.3 – Spicules (Table 3): (i) Tripods (Figure 5 E): Regular or irregular with an elevated centre. Actines are the same length or not. They are conical, curved, with blunt tips. However, they are not stout as typical tripods; (ii) Triactines (Figure 5 F): Regular. Actines are cylindrical, very long and thin, with blunt tips; (iii) Tetractines: Very rare. They are similar to the triactines. The apical actine could not be observed. Remarks: Jenkin (1908) described Leucascus leptoraphis as Leucandra primigenia var. leptoraphis, after transferring Leucetta primigenia Haeckel, 1872 to the genus Leucandra. Haeckel (1872) described Leucetta primigenia comprising three varieties: microraphis, isoraphis and megaraphis. Jenkin (1908) added the new variety leptoraphis that, according to him, was similar to isoraphis except for the size of the spicules that were more slender in his variety. He also mentioned the presence of “alate triradiates”, which we understand as being the tripods. In 1929, Burton elevated Leucandra primigenia var. leptoraphis to the species rank and transferred it to the genus Leucetta. He also synonymized L. leptoraphis with Leucetta antarctica Dendy, 1918 but without justifying his action. Nevertheless, according to its original description, in L. antarctica the cortical and choanosomal triactines are similar, while in L. leptoraphis the cortical skeleton is composed of tripods. Years later, Burton (1963) also synonymized “ Leucetta ” leptoraphis with Leucetta isoraphis var. apicalis Brøndsted, 1931. However, they are very different species, being the former currently accepted as Soleneiscus apicalis (Borojevic et al., 2002). Leucandra primigenia var. leptoraphis is indeed a species of Leucascus, as it is formed by anastomosed tubes and has cortical and atrial membranes. It should be noted that the spicule composition and organisation as well as general morphology is quite similar to what is found in Ascaltis abyssus described from the Weddell Sea, Antarctica (Rapp et al. 2011). However, the spicules are generally smaller in L. leptoraphis and the true atrial membrane characteristic for Leucascus is absent in A. abyssus. Distribution: Antarctic Ocean: McMurdo Bay (Jenkin 1908), and Turtle Rock, McMurdo Sound—Antarctica; Argentina (Gappa & Landoni 2005). Spalding et al. (2007) corresponding ecoregions: Ross Sea and Malvinas / Falklands.Published as part of Cavalcanti, Fernanda F., Rapp, Hans Tore & Klautau, Michelle, 2013, Taxonomic revision of Leucascus Dendy, 1892 (Porifera: Calcarea) with revalidation of Ascoleucetta Dendy & Frederick, 1924 and description of three new species, pp. 275-314 in Zootaxa 3619 (3) on pages 283-285, DOI: 10.11646/zootaxa.3619.3.3, http://zenodo.org/record/22185
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
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
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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