25,689 research outputs found
Além da enxada, a utopia: a colonização italiana no oeste catarinense
Get PDFDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas. Programa de Pós-Graduação em História.Através da teoria e metodologia da História Oral, busca perceber a experiência migratória dos italianos e seus descendentes que migraram da Região Colonial Italiana, no Rio Grande do Sul, para o Oeste de Santa Catarina, a partir das primeiras décadas do séc. XX. Apresenta vários aspectos do cotidiano dos migrantes na nova terra, como o trabalho, o lazer e a família. Analisa quais as representações do passado são transmitidas pelas pessoas que vivenciaram a referida experiência migratória
Statistical characterization of free-stream turbulence induced transition under variable Reynolds number, free-stream turbulence, and pressure gradient
No full textIn this work, the free-stream turbulence (FST) induced transition of a flat plate boundary layer is studied using particle image velocimetry (PIV) under variable Reynolds number (Re), FST intensity, and adverse pressure gradient (APG). Overall, 10 different flow conditions were tested concerning the variation of these parameters. The streak spacing and the probability density function (PDF) of turbulent spot nucleation are computed for all cases. The streak spacing is shown to be constant in the transition region once scaled with the turbulent displacement and momentum thickness, with resulting values of around 3 and 5, respectively. Nucleation events are shown to occur near the position where the dimensionless streak spacing reaches such constant values. The streamwise position where most turbulent spots are formed is strongly influenced by the FST intensity level. Additionally, the PDF of spot nucleation becomes narrower with increase in the APG, while FST has the opposite effect. A common distribution of all the PDFs is provided as a function of a similarity variable accounting for the streak spacing, the shape factor of the boundary layer, and the FST intensity
Caridina simoni Bouvier 1904
No full textCaridina simoni Bouvier, 1904 (Figs. 1, 2) Caridina simoni Bouvier, 1904: 131; 1905: 73, 80, fig. 4; 1912: 918. Caridina aruensis J. Roux, 1911: 82; Bouvier, 1913 a: 463; 1913 b: 181. Caridina nilotica var. simoni Bouvier, 1925: 157, figs. 327–331. Caridina nilotica simoni Arudprakasam & Costa, 1962: 19; Costa, 1972: 130. Caridina nilotica var. aruensis J. Roux, 1920: 321; 1926 b: 248; Bouvier, 1925: 156; Reik, 1953: 118, fig. 7. Caridina simoni simoni de Silva 1983: 205, 208, 209. Caridina kunnathurensis Richard & Chandran, 1994: 250, fig. 4; Mariappan & Richard, 2006: 30, figs. 15–17; Ragunathan & Valarmathi 2007: 95. Material examined. Types: Syntypes. Sri Lanka (Ceylon). coll. E. Simon, 1904, MNHN Na 856 2 ♂, 1 ♂ selected as a lectotype now MNHN-IU- 2013 -11816, 1♂ as a paralectotype now MNHN-IU- 2008-14721; Cotype, coll. E. Simon, 1904, exch. Paris Museum, 117 - 97, NHM reg. 1907.1. 7.33, 1 ♀, selected as a paralectotype. Non types: Sri Lanka. irrigation streams, Peradeniya, pres. R. Gurney, NHM reg.1920.2.5.11–13, 4♀; stream running in to Mahawallagunga River, Peradeniya, pres. R. Gurney, NHM reg. 1920.2.5.14–16, 1♂, 1 ♀ ovig., 1 ♀, 1 damaged specimen; Keani River, Kekirawa, Colombo, pres. D.R.R. Burt, NHM reg. 1935.5.30.26–27, 4♂, 3 ♀; Kalaweva, April 1932, pres. D.R.R. Burt, Department of Zoology, University College, NHM reg. 1935.5.30.15–19, 1♂ (abnormal), 4 ♀ ovig., 2 ♀; from streams running into Mahawallaganja, pres. Dr. R. Gurney, det. W.T. Calman NHM reg. 1947.3.18, 1♀ ovig; pres. Dr. R. Gurney, NHM reg. 1950.1. 2.148, dissected parts; irrigation streams, Peradeniya, pres. Dr. R. Gurney, NHM reg. 1951.2. 17.1792 /3, 1♂, 1 ♀; fresh water pond, Botanical Gardens, Perademiya, 17.6. 1954, coll. & pres. E.S. Brown, NHM reg. 1954.10.27.1–10, 20♂, 5 ♀ ovig., 7 ♀; Ambanganga Anoiont, nr. Polonarraw, 1962, coll. & pres. C.H. Fernandes, NHM reg. 1962.8.24.104, 3♀ ovig., 1 ♀. India. Hindupur, S. India. coll. P.K. Sartory, pres. Mr. Scourfield, det. J. Richard & P. Cark 2009, NHM reg. 1945.vii. 27.5 –12, 3♂, 4 ♀; Madras (Chennai) area, coll. and pres. Dr. Sanjeevaraj, det. I. Gordon, 0 5. 1965. NHM reg. 1965.5.7.1–10, 31♀ ovig. Other material: Caridina aruensis. Types: Syntype. Indonesia. Ruisseau Matora, Soungi Manoumbai, Isle Arou, coll. H. Merton, 15.3. 1908, Papouse Muse de Bale, 1913, MNHN reg. Na 664, 1♂; Cotypes. Ruisseau Matora, Soungi Manoumbai, Isle Arou, coll. H. Merton 15.3. 1908, Papouse Muse de Bale, 1913, MNHN reg. Na 665, 2♂, 1 ♀ ovig. Caridina kunnathurensis. Paratype. India. Kunnathur, 25 kilometers from Madras (now Chennai), Tamilnadu state, 1982, coll. & pres. J. Richard, RMNH reg. D 35564, 1♂, 4 ♀ ovig. Description. Adult size 18–32 mm. Carapace length 3.5 –4.0 mm. Rostrum (Fig. 1 a–c): Slender, 1.0– 1.2 ×long as carapace, reaching antennal scale or slightly longer. Dorsal margin with 15–25 proximal teeth leaving distally 0.25–0.4 unarmed or interrupted by 1–4 teeth. 3–5 post orbital teeth present. Tip pointed. Ventral margin with 5–14 teeth proximally leaving the distal margin unarmed. However, 1 ♀ from Kalaweva, Sri Lanka possessed 19 teeth on the ventral margin which is considered to be an exceptional occurrence. Formula (3–5) 15–25 + 0–4 / 5–14. Antennular peduncle (Fig. 1 a–c): 0.6–0.9 ×carapace. Stylocerite 0.6–0.7 ×length of basal segment. Anterolateral teeth of basal segment 0.19–0.25 ×second segment. 15–25 segments bearing aesthetascs. First pereiopod (Fig. 2 a): Dactylus 1.1–1.3 ×palm of propodus. Chela 1.7–2.3 ×long as broad. Carpus 1.8–2.3 ×long as broad, anterior excavation shallow. Second pereiopod (Fig. 2 b): Long and slender. Dactylus 1.2 –2.0×long as palm of propodus. Chela 2.3–2.9 ×long as broad. Carpus 4.5–5.5 ×long as broad. Third pereiopod (Fig. 2 c, d): Dactylus 2.0–3.0×long as broad. 6–9 spines on dactylus (including terminal spines), mostly 6–7. Propodus 5.0– 5.6 ×long as dactylus and 9–12 ×long as broad with 10–14 spines along inner margin. Carpus 0.45–0.6 ×long as propodus, with 1 large spine and 3–5 minute spines on inner margin. Merus 1.6 –2.0×carpus length. Merus with 4 large spines on posterior margin. Ischium with a spine Fifth pereiopod (Fig. 2 e, f): Dactylus 3.9 –5.0×long as broad with 35–60 spines in comb-like fashion on inner margin. Propodus 10–14 ×long as broad and 3.2–3.9 ×long as dactylus and with 10–15 spines along posterior margin. Carpus 0.45–0.7 ×propodus length and with minute spines along inner margin. Merus 1.5 –2.0×carpus length, with 3 large spines at posterior margin. Ischium with a spine. Setobranchs: 2 setae on all pereiopods. First male pleopod (Fig. 2 g–i): Endopod 0.25–0.35 ×exopod length and usually possess a distinct appendix interna, but in 1 ♂ from Hindupur appendix interna absent. Several long setae present along the entire margin. First female pleopod (Fig. 2 j): Ratio of the endopod to exopod length varies remarkably from 0.35–0.8. Eggs (Fig. 2 k): 50– 160 eggs of 0.65 –1.0× 0.45–0.6 mm size. Second male pleopod (Fig. 2 l, m): Appendix masculina 1.4–1.7 ×appendix interna and 0.3–0.4 ×endopod. 6 th abdominal somite: 0.57–0.86 ×long as carapace. Telson (Fig. 2 n, o, p): Broad, 1–1.15 ×long as 6 th abdominal somite. Dorsal spines 4–6 pairs (including subterminal spine). Posterior margin broad and rounded, mostly without a median process, bearing 1 pair of long lateral spines and 3–4 pairs sparsely plumose spines that are of equal length and shorter than laterals or central pair fractionally longer and of equal length to lateral spines. Uropod (Fig. 2 q): 8–14 diaeresis spinules. Preanal carina (Fig. 2 r): Unarmed. Distribution. Sri Lanka; India; Aru Islands, Indonesia and Australia. Type locality. Ceylon (Sri Lanka). Remarks. Bouvier (1904) initially provided a brief description of C. simoni stating that the species lacked a subapical tooth, possessed a long rostrum reaching beyond the antennular peduncle and dorsal and ventral rostral margins were unarmed distally. He considered that his new species was near to C. wycki var. gracilipes De Man, 1892 and C. ensifera Schenkel, 1902. Later, Bouvier (1905) described C. simoni in more detail and included an illustration of the anterior region of the cephalothorax as well as the first, second and fifth pereiopods. He highlighted a number of diagnostic characters for C. simoni including the rostrum being longer than the antennular peduncle, absence of subapical teeth and distally ⅓ of the dorsal margin and ¼ of the ventral margin being unarmed. Bouvier (1905) also noted the dental formula in a key, 2 + 16 – 4 + 18 / 8–11. However, during his study of C. nilotica (P. Roux, 1833) and its varieties, Bouvier (1925) referred to C. n. simoni. He provided illustrations of the first male pleopod with the appendix interna, carpus and epipod of the first pereiopod, and the posterior margin of the telson. Throughout his studies, Bouvier (1904, 1905, 1925) confirmed that the tip of the rostrum in C. n. simoni was always pointed, a character later noted by Arudprakasam & Costa (1962) and confirmed by Costa (1972). In fact, Arudprakasam & Costa (1962) distinguished their new subspecies of C. n. zeylonica from C. n. simoni mainly on the basis of the morphology of the rostrum. They also considered the absence of a sub-apical tooth in C. n. simoni as an important distinguishing feature. Johnson (1963) based his studies mainly on miscellaneous observations of specimens from European museums. He described C. simoni as, “a rather stout species which is distinctly more heavily built than specimens of true C. nilotica which I have seen, though the distinction is both difficult to describe and to figure”. This statement is superficial and appears not to be based on any diagnostic characters. Furthermore, Johnson (1963) synonymised several distinct species (see Table 1) that he considered junior synonyms of C. simoni. Therefore Johnson’s concept of C. simoni is questionable and his reference to this species is not included in the above synonymy. Truly the synonymy of Johnson (1963) was responsible for the difficulties in identifying C. simoni and several other distinct species. de Silva (1982) described a new species of Caridina from Sri Lanka namely Caridina costai and considered it to be closer to C. simoni. He distinguished C. costai by its broad shorter rostrum that just reaches the antennular peduncle or is shorter (vs. a slender rostrum that reaches beyond the antennular peduncle in C. simoni). de Silva (1982) also provided several other measurements that appear to fall within the range of C. simoni. The examination of more C. simoni samples by the present study confirms that the slender rostrum of C. simoni is slightly longer than the antennal scale but not shorter than the antennular peduncle and in addition, there are more teeth on the ventral margin of the rostrum in C. simoni 5–14 (vs. 5–8 in C. costai). Benzie & de Silva (1984) who tried to prevent “nomenclatural confusion”, rejected the decision by Johnson (1963) of affording species status to C. n. simoni because they considered that he provided no numerical data. Also, they (Benzie & de Silva 1984) considered C. n. zeylonica of Arudprakasam & Costa (1962) and C. costai of de Silva (1982) as population variants of C. n. simoni. Further, Benzie & de Silva (1984) decided that rostral shape and spinulation are highly unreliable taxonomical characters in Atyidae. With reference to Johnson (1963), Benzie & de Silva (1984) emphasised the need for numerical data and reliable characters when making taxonomic decisions. Their identification of C. costai, C. n. simoni and C. n. zeylonica was based on three characters, the proportion of the 6 th abdominal segment to carapace, dactylus to propodus length of the 5 th pereiopod and the spinules on the dactylus of the fifth pereiopod. The measurements as presented by them (Benzie & de Silva, 1984) are overlapping for the three species. Their total rejection of rostral morphology as a taxonomic character for Caridina with reference to Smith & Williams (1980) could lead to misidentification. Caridina requires a combination of several taxonomic characters for valid identification. The morphology, number of teeth and their placement on the rostrum are important identification characters. Based on the examination of type and non-type specimens from Sri Lanka and India, the present study considers C. simoni to be a valid and distinct species. The following features are characteristic of the species: rostrum long and slender, reaching antennal scale or slightly longer, tip of the rostrum always pointed, 15–25 teeth proximally on the dorsal margin leaving 0.25–0.4 distally unarmed or interrupted by 1–4 teeth, 3–5 post orbital teeth present, 5–14 teeth proximally on the ventral margin leaving distal end unarmed, rostral formula (3–5) 15–25 + 0–4 / 5–14; carpus of the first pereiopod 1.8–2.3 ×long as broad, anterior excavation shallow, 6–9 spines on dactylus of third pereiopod, propodus 3.2–3.9 ×long as dactylus, 30–60 spines on dactylus of fifth pereiopod; posterior margin of telson rounded mostly without a median process, bearing 1 pair of long lateral spines and 3–4 pairs of sparsely plumose spines that are either equal in length and shorter than the lateral spines or the central pair of equal length to the lateral spines; 8–14 uropod diaeresis spinules present; ca. 50– 160 eggs of 0.65 –1.0× 0.45–0.6 mm in size; endopod of the first male pleopod usually with an appendix interna, rarely without. The type specimens of C. aruensis J. Roux, 1911 were examined and the following characters are confirmed: Adult size 20–25 mm; rostrum equal to or slightly longer than the antennal scale, tip pointed, formula (3–4) 20–25 / 7–9 with 0.25–0.4 of the dorsal margin unarmed distally or interrupted by 1–3 teeth, ventral margin with a short unarmed end distally, posterior margin of the telson rounded with a pair of long lateral spines and 2 pairs or 3 intermediate spines of equal length; 6–14 uropod diaeresis spinules; endopod of the male first pleopod with appendix interna and preanal carina unarmed. It was noted that the number of intermediate spines on the posterior margin of telson is lesser when compared to C. simoni (3–4 pairs). Based on these observations, the present study confirms the decision of Johnson (1963) and considers C. aruensis to be a junior synonym of C. simoni. From the description of C. n. aruensis by J. Roux (1920, 1926b), it is accepted that C. simoni is distributed in Indonesia and Australia. In addition, the paratypes of C. kunnathurensis Richard & Chandran, 1994 from Kunnathur near Madras were re-examined and this species is considered to be a junior synonym of C. simoni. In addition, the present study examined more specimens from Hindupur, Andhra Pradesh, and Madras, India, and confirms that the distribution of C. simoni is extended to India. Furthermore, after examining a series of type and non-type specimens the present study considered that the many species that Johnson (1963, Table 1) listed as junior synonyms of C. simoni, are in fact valid species and the following nomenclatural changes are required.Published as part of Richard, Jasmine & Clark, Paul F., 2014, Caridina simoni Bouvier, 1904 (Crustacea: Decapoda: Caridea: Atyoidea: Atyidae) and the synonymy by Johnson, 1963, pp. 301-338 in Zootaxa 3841 (3) on pages 303-308, DOI: 10.11646/zootaxa.3841.3.1, http://zenodo.org/record/22824
Pitch tuning induced by optical torque in heliconical cholesteric liquid crystals
No full textHeliconical cholesteric liquid crystals are expected to be more sensitive to torque induced by light field since their structure allows both bend and twist in molecular orientations, differently from the conventional cholesterics in which only twist deformation is involved, requiring much higher fields. We report here a demonstration of tuning the helical pitch in heliconical cholesterics induced by an optical torque. Experimental observations are in agreement with expectations of the classical theory extended to include the effect of the optical field. A dual control of the helical pitch is achieved including both the low-frequency electric field applied along the helix axis and the optical field orthogonal to it
Heliconical cholesteric liquid crystals as electrically tunable optical filters in notch and bandpass configurations
No full textHeliconical cholesteric liquid crystals are a recently proposed novel class of liquid crystalline materials in which the chiral pitch can be tuned by an external electric field acting parallel to the helical axis. Here we show that these materials can be used as tunable optical filters of a simple architecture. The spectral properties of transmitted light can be tuned within the whole visible range. In particular, the bandpass wavelength can be shifted from 405 nm to 637 nm by changing the applied field from 2.7 to 1.7 V/μm. The electric field can also switch the filters on and off, within 1 s or less. Moreover, the filters work with both polarised and unpolarised light and can be switched from a notch to a bandpass configuration by changing the polarisation of incident light. An optical switch among three different laser lines is also reported as an additional possible application
Synthesis and antiproliferative activity of 2'-O-allyl-1-beta-D-arabynofuranosyl-uracil, -cytosine and -adenine
No full textWith the aim to design potential inhibitors of ribonucleotide reductase (RR), 2'-O-allyl-β-D-arabinofuranosyl-uracil (4), -cytosine (7) and -adenosine (10) were prepared and evaluated for their cytostatic activity against Molt4/C8, CEM and L1210 cell lines. Although our preliminary data do not allow to assess if RR is the intracellular target, the results point to differences in the (anti)metabolic behavior of these compounds. This study also offers a general synthesis of 2' -O-allyl-β-D-arabinofuranosyl nucleosides for potential applications in the preparation of 2'-O-allyl-β-D-oligoarabino nucleotides.With the aim to design potential inhibitors of ribonucleotide reductase (RR), 2'-O-allyl-β-D-arabinofuranosyl-uracil (4), -cytosine (7) and -adenosine (10) were prepared and evaluated for their cytostatic activity against Molt4/C8, CEM and L1210 cell lines. Although our preliminary data do not allow to assess if RR is the intracellular target, the results point to differences in the (anti)metabolic behavior of these compounds. This study also offers a general synthesis of 2' -O-allyl-β-D-arabinofuranosyl nucleosides for potential applications in the preparation of 2'-O-allyl-β-D-oligoarabino nucleotides
Ixchela simoni O. Pickard-Cambridge 1898
No full text<i>Ixchela simoni</i> (O. Pickard-Cambridge, 1898) <p>Figures 72–84</p> <p> <i>Coryssocnemis simoni</i> O. Pickard-Cambridge, 1898: 237, pl. 31, fig. 9 (description Ƥ). <i>Coryssocnemis simoni</i> F. O. Pickard-Cambridge, 1902: 371, pl. 35, fig. 7 (Ƥ). <i>Ixchela simoni.</i> Huber, 2000: 153 (Ƥ transfer from <i>Coryssocnemis</i>).</p> <p> <b>Type data.</b> <i>MEXICO</i>: <i>Guerrero</i>: 1 Ƥ holotype (BMNH) (not examined), from Omiltemi [~ lat 17.5564°, lon - 99.6882°], Municipio Chilpancingo [H. H. Smith].</p> <p> <b>Material examined.</b> <i>MEXICO</i>: <i>Guerrero</i>: 2 3, 2 ƤƤ, 2 immatures (CNAN 3320) [25 January 2012; A. Valdez, O. Francke, D. Ortiz, J. Mendoza, G. Contreras] from 2 km W of crossroad Omiltemi-Chautipan (lat 17.5552°, lon - 99.7236°; 2448 m), Municipio Chilpancingo. 1 immature (CNAN 3321) [25 January 2012; A. Valdez, O. Francke, D. Ortiz, J. Mendoza, G. Contreras] from 1 km E of Omiltemi (lat 17.5561°, lon -99.6729°; 1985 m), Municipio Chilpancingo. 2 immatures (CNAN 3322) [25 January 2012; A. Valdez, O. Francke, D. Ortiz, J. Mendoza, G. Contreras] from 2 km W of Omiltemi (lat 17.5481°, lon -99.6956°; 2216 m), Municipio Chilpancingo. 4 immatures (CNAN 3328) [23 July 2009; A. Valdez, O. Francke, H. Montaño, C. Santibañez, T. López, C. Quijano] from Omiltemi (lat 17.5546°, lon -99.6853°; 2623 m), Municipio Chilpancingo. 1 Ƥ (TMM-UT Inv. Zoo. Coll. # 52,512) [29 December 2002; P. Sprouse] from Acahuizotla, Resumidero de San Juan Francisco (lat 17.3253°, lon -99.3909°; 1222 m).</p> <p> <b>Diagnosis.</b> Close relative of <i>I. huberi</i>, distinguished by chelicerae with FAC rounded and smaller (Figs 74, 75); rounded apically in lateral view (Fig. 75); by the palp femur larger (Figs 78, 79); by the embolus ventral-distal with long projection leaf-shaped (Fig. 80); and by epigyna with prominent conical apophysis (Fig. 82), slightly curved in lateral view (Fig. 84).</p> <p> <b>Description. Male.</b> (CNAN 3320). <i>Prosoma:</i> Carapace pale yellow, with lateral wide spots, olive color (Fig. 73). Ocular region brown, with a wide longitudinal olive line; two shorts olive lines behind the posterior median eyes (Fig. 73). Fovea with a wide spot aroud it, olive color (Fig. 73). Clypeus with a wide trapezoidal region along, olive color (Fig. 76). Chelicerae dark brown on prolateral and retrolateral parts; prolaterally small pale region on basal and distal parts. FAC brown, quelicerae with inconspicuous SAC (Fig. 74). Sternum orange, labium and endites brown, pale distally, prolateral apophysis of endites orange. <i>Legs:</i> Coxae pale yellow. Trochanters brown. Femora orange, paler basally and distally, with a marked width ring sub-distally. Patellae dark. Tibiae light brown, with a dark wide ring basally and other one distally. Metatarsi and tarsi brown. <i>Opisthosoma:</i> Conical, pale blue, larger than high (Fig. 72). Gonopore plate olive color, rounded. <i>Palp:</i> Femur pale orange, conical, thin basally and wide distally; with VAF small, projected upward (Fig. 78). Patella pale orange. Tibia orange, paler basally. Procursus brown, paler basally; conical with distal curved spine; with two dorsal basal projections (Fig. 77). VPP rounded, with numerous long setae (Fig. 78). Embolus conical (Figs 78, 79), with sclerotized spine small and sub-distal on the embolus (arrow Fig. 80). PAB long and wide (Fig. 79). Embolus with long curved dorsal-distal spine; ventrally with sclerotized long projection leaf-shaped (Fig. 80). <i>Measurements:</i> Total length 7.40. Carapace 2.85 long, 2.50 wide. Clypeus 1.07 long. Diameter AME 0.14, ALE 0.24, PME 0.20, PLE 0.22. Distance ALE-PME 0.18, PME-PME 0.26. Leg I: 40.19 (10.81+1.02+10.62+13.12+4.62). tibia II: 7.25, tibia III: 5.70, tibia IV: 7.40; tibia I l/d 21.50.</p> <p> <b>Female.</b> (CNAN 3320). Similar to the male, differences: <i>Prosoma:</i> Chelicerae brown. Dorsal lateral spots darker than on males. Ocular region darker than on males. Spot around the fovea darker than on males. Clypeus with very maked long straight region, not trapezoidal. Sternum and endites darker than on males. <i>Legs:</i> femora, tibiae, metatarsi and tarsi paler than on males. <i>Epigynum:</i> Slightly wider than long (Figs 81, 82, 84). PP curved laterally; MSE with a marked Y-shaped upside down; long concavities sac-like between MSE and PP (Fig. 83). <i>Measurements:</i> Total length 7.70. Carapace 2.65 long, 2.45 wide. Clypeus 0.90 long. Diameter AME 0.12, ALE 0.25, PME 0.22, PLE 0.26. Distance 0.23, ALE-PME 0.18. PME-PME 0.27. Leg I: 36.60 (9.62+1.10+10.00+11.75+4.13), tibia II: 6.70, tibia III: 5.30, tibia IV: 6.87; tibia I l/d 22.85.</p> <p> <b>Variation.</b> Females have carapace yellow paler than the males. The carapace and clypeus pattern are darker olive on females than males. Sternum and legs darker orange on males than females. Labium markedly darker in females than males. Male tibia I: 10.62, missing. Female tibia I: 10.00, missing.</p> <p> <b>Natural History.</b> The specimens were collected on their sheet webs in an oak-pine forest (Fig. 4), among boulders and on walls along road-cuts in wet and shaded areas covered with roots (Figs 17, 18).</p> <p> <b>Distribution.</b> <i>MEXICO: Guerrero</i> (O. Pickard-Cambridge 1898, F. O. Pickard-Cambridge 1902) (Fig. 85).</p>Published as part of <i>Valdez-Mondragón, Alejandro, 2013, Taxonomic revision of the spider genus Ixchela Huber, 2000 (Araneae: Pholcidae), with description of ten new species from Mexico and Central America, pp. 285-327 in Zootaxa 3608 (5)</i> on pages 302-304, DOI: 10.11646/zootaxa.3608.5.1, <a href="http://zenodo.org/record/216512">http://zenodo.org/record/216512</a>
Effect of free-stream turbulence properties on different transition routes for a zero-pressure gradient boundary layer
No full textThe natural and bypass routes to boundary-layer transition to turbulence are traditionally investigated independently in fluid mechanics applications. Nevertheless, in certain flow regimes both mechanisms could coexist and interact. In this work, large-eddy simulations (LES) were performed for a zero-pressure gradient boundary layer developing over a flat plate to investigate the transition mechanism for variable free-stream turbulent properties. Four different combinations of turbulence intensity and integral length scale were analyzed, and two main transition mechanisms were observed. High free-stream turbulence intensity instigates pure bypass transition through the amplification of a continuous Orr-Sommerfeld (O-S) mode that breaks down after secondary instability. Instead, at low free-stream turbulence intensity, discrete and continuous O-S modes interact and are both involved in the transition process. Visual inspection of the LES snapshots provides a detailed insight in Tollmien-Schlichting (TS) waves-streaks mutual interaction and clearly identifies two main mechanisms involved in turbulence breakdown. On one hand, TS waves trigger varicose instability of streaky structures. On the other hand, streaks cause secondary instability of TS waves with emerging Lambda-structure formation. Then, dynamic mode decomposition (DMD) is applied to extract the main stability properties for both types of transition route and to highlight coherent structure dynamics, which is hardly observable in the literature. Specifically, for low-medium free-stream turbulence levels, DMD extracts unstable modes clearly related to streaks-TS waves interaction and leading to the formation of Lambda structures. Therefore, the streaks-TS waves interaction is proved to be destabilizing and to trigger secondary instability leading to turbulence breakdown. Published under an exclusive license by AIP Publishin
FIGURE 2. Caridina simoni Bouvier, 1904, NHM 1945.vii.27.5–12 in Caridina simoni Bouvier, 1904 (Crustacea: Decapoda: Caridea: Atyoidea: Atyidae) and the synonymy by Johnson, 1963
No full textFIGURE 2. Caridina simoni Bouvier, 1904, NHM 1945.vii.27.5–12, ♂: a) First pereiopod; b) Second pereiopod; c) Third pereiopod; d) Dactylus of the third pereiopod; e) Fifth pereiopod; f) Dactylus of fifth pereiopod; g) First male pleopod; h) endopod of first male pleopod; ♂: i) Endopod of first male pleopod; NHM 1935.5.30.15–19, ♀ ovig.: j) First female pleopod; k) Egg. NHM 1945.vii.27.5–12, ♂: l) Second male pleopod; m) Appendix masculina; n) Telson; o) Posterior margin of telson; NHM 1907.1.7.33, Cotype now Paralectotype, ♀: p) Posterior margin of telson; NHM 1945.vii.27.5–12, ♂: q) Uropod diaeresis spinules; r) Preanal carina.Published as part of Richard, Jasmine & Clark, Paul F., 2014, Caridina simoni Bouvier, 1904 (Crustacea: Decapoda: Caridea: Atyoidea: Atyidae) and the synonymy by Johnson, 1963, pp. 301-338 in Zootaxa 3841 (3) on page 306, DOI: 10.11646/zootaxa.3841.3.1, http://zenodo.org/record/22824
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
Get PDFBoth 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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