7,653 research outputs found
The impact of textual sentiment on sovereign bond yield spreads: evidence from the Eurozone crisis
No full textThis study examines the relation between textual sentiment, the concentration/volume of news, and sovereign bond yield spreads, specifically in Greece, Ireland, Italy, Portugal and Spain during the European sovereign debt crisis (January 2009 to December 2012). The results are consistent with the story that investors of sovereign bonds respond to rising negative sentiment accompanied by an increased concentration/volume of news. If the change of the interaction measures increases by 1 unit and other factors remain unchanged, the change of yield spreads would move upwards by approximately 18 to 32 basis points, putting downward pressure on prices. Negative sentiment and the number of news stories respectively and collectively help predict the widening of yield spreads. A higher negative sentiment level is strongly associated with more news stories being reported, suggesting that “no news is good news.” Overall, textual sentiment conveys potential pricing-relevant information over and above the traditionally identified factors
Litarcturus kexueiae Liu & Sha, 2015, sp. nov.
No full text<i>Litarcturus kexueiae</i> sp. nov. <p>Figs 1–5</p> <p> <b>Material examined.</b> Holotype, adult male (total length, 13.8 mm, without antennae), MBM 240861, Okinawa Trough (27°40.300´N; 126°54.174´E), RY0231, depth 2115 m, bottom sandy mud, coll. Zhongli Sha, by Agassiz trawl, 23 April 2014.</p> <p> <b>Description.</b> Body (Fig. 1 A–B) length 13.8 mm. Eyes rounded, large and protruding, 0.36 of lateral length of cephalothorax. Body long, slender, pereonite 1 fused with head; dorsal transverse ridge between cephalothorax and pereonite 1. Preocular spines absent; supraocular spines long, slender and directed anteriorly, unarmed, not covering the eyes in dorsal view, about 3.0 times as long as diameter of eye. Further dorsal spines are lacking. All pereonites unarmed, with rough cuticle. Pereonites 1–3 of about same length and width; pereonite 4 longest, slightly narrower than pereonites 1–3, of about the same width as pereonites 6–7; pereonite 5 slightly longer than pereonites 4 and 6–7. Tergites of pereonites 5–7 with concave posterior border into which the following segment fits when the animal bends dorsally.</p> <p>All pleonites fused with pleotelson, unarmed. Pleotelson length about 0.25 times body length, width about 0.5 of total pleotelson length, partly with small scattered tubercles. Posterolateral pleotelsonic spines strong and straight, unarmed, at 0.62 of pleotelson length, about 0.6 times as long as caudal part of pleotelson. Pleotelson apex prominent, triangular and caudally rounded.</p> <p>Antennula (Fig. 3 A): length 0.18 times body length, with 2 flagellar articles; peduncular article 1 broadest, 1.4 times longer than wide and shorter than second one, unarmed; article 2 longest, 1.2 times as long as article 1, unarmed; article 3 slightly shorter than article 2, unarmed; flagellar article 1 a very short ring with 1 lateral slender bristle; article 2 2.6 times as long as peduncular article 3, with 8 groups of 2 aesthetascs accompanied by several simple setae, apically 2 terminal simple setae and another 2 aesthetascs.</p> <p>Antenna (Fig. 3 B): peduncle length 0.9 times body length; article 2 short, 0.3 length of article 3, with 2 parallel rows of short setae; articles 3 and 4 with 2 parallel rows of setae, arranged in groups of 1 long and 1 shorter setae; article 5 long and slender, with a row of short setae, arranged in groups of 1 long and 1 shorter setae; flagellum broken, article 1 with 2 parallel rows of short setae.</p> <p>Mouthparts typical of the family (Fig. 2 A–C).</p> <p>Maxilliped (Fig. 2 D) with a long oval-shaped epipod, strong endite and five-segmented palp. Epipodite covered with fine setae laterally and medially. Endite as long as epipodite, surpassing the middle of the second palp article, distal margin covered with fine setae and 7 robust setulate setae, distolaterally with 3 short plumose setae.</p> <p>Palp article 1 shortest, length 0.7 times length of second article, with few short simple setae on ventral margin and ventrolateral surface; palpal article 2 with short simple setae on ventral margin and ventrolateral surface; article 3 longest, 1.9 times longer than article 2, with dense simple and pectinate setae on ventral margin and ventrolateral surface and 2 long pectinate setae dorsodistally; article 4 about 1.5 times as long as article 2, with dense simple and pectinate setae on ventral margin and ventrolateral surface and 4 long pectinate setae dorsodistally; article 5 1.4 times longer than article 1, with long simple and pectinate setae apically.</p> <p>Pereopod 1 (Fig. 3 C) more robust than pereopods 2–7; basis longer than propodus, 2.1 times longer than wide, distoventrally with several long and slender simple setae, dorsal surface equipped with row of setules; ischium 0.9 times basis length, 1.7 times longer than wide, ventrally with dense long simple setae on distal half; merus 0.5 times ischium length, 1.8 times wider than long, with dense long simple setae ventrally and 2 anterodistal setae, carpus trapezoidal, 1.6 times wider than long, about as long as merus, with dense long simple setae ventrally; propodus subchelate and slender, 2.2 times carpus length, twice as long as wide; ventrally and partly laterally with dense long slender simple setae, dorsolateral surface with dense pectinate setae; dactylus shorter than propodus, 3.3 times longer than wide, with a unguis and a secondary unguis, and between bearing a seta, with several long and slender simple setae.</p> <p>Pereopods 2–4 similar, with long setae on posteromedial margins, without spines on anterolateral margins; long filter setae present on ischium, merus, carpus and propodus but lacking on dactylus (unknown in pereopod 3). Pereopod 2 (Fig. 3 D) basis 1.8 times longer than wide, dorsally unarmed, distoventrally with several long and slender simple setae; ischium length 0.7 times basis length, 1.4 times longer than wide, dorsally unarmed, ventrally with 2 parallel rows of setae, every row with 6 groups of setae and arranged in groups of 1 long filtering seta and 1 shorter simple seta; merus 1.5 times ischium length, 1.8 times longer than wide, with 1 small simple seta distodorsally, ventrally with 2 parallel rows of setae, every row with 6 groups of setae and arranged in groups of 1 long filtering seta and 1 shorter simple seta; carpus 2.2 times merus length, 6.8 times longer than wide, with several small simple setae dorsally, ventrally with 2 parallel rows of setae, every row with 16 groups of setae and arranged in groups of 1 long filtering seta and 1 shorter simple seta; propodus almost as long as carpus, 9.8 times longer than wide, with 2 moderate setae and 3 small simple setae dorsally, ventrally with 2 parallel rows of setae, every row with 14 groups of setae and arranged in groups of 1 long filtering seta and 1 shorter simple seta; dactylus 0.5 times propodus length, 11.1 times longer than wide, with 4 small simple setae dorsally, 2 small simple setae ventrally; unguis 0.5 times dactylus length, with a short ventral claw and a medial seta.</p> <p>Pereopod 3 (Fig. 4 A) basis 2.8 times longer than wide, dorsally unarmed, distoventrally with several long and slender simple setae; ischium 0.6 times basis length, 1.6 times longer than wide, dorsally unarmed, ventrally with 2 parallel rows of setae, every row with 7 groups setae and arranged in groups of 1 long filtering and 1 shorter simple seta; merus 1.5 times ischium length, 2.1 times longer than wide, dorsally unarmed, ventrally with 2 parallel rows of setae, every row with 7 groups setae and arranged in groups of 1 long filtering and 1 shorter simple seta; carpus 2.3 times merus length, 6.5 times longer than wide, with several small simple setae dorsally, ventrally with 2 parallel rows of setae, every row with 15 groups of setae and arranged in groups of 1 long filtering and 1 shorter simple seta; propodus broken off.</p> <p>Pereopod 4 (Fig. 4 B) basis 3.6 times longer than wide, dorsal margin with a big triangular tooth and scattered with several small tubercles, distoventrally with several long and slender simple setae; ischium 0.6 times basis length, 2.6 times longer than wide, dorsally unarmed, ventrally with 2 parallel rows of setae, every row with 7 groups of setae and arranged in groups of 1 long filtering and 1 shorter simple seta; merus almost as long as ischium, 2.3 times longer than wide; with 1 small simple seta distodorsally, ventrally with 2 parallel rows of setae, every row with 7 groups of setae and arranged in groups of 1 long filtering and 1 shorter simple seta; carpus 2.0 times merus length, 5.0 times longer than wide, with several small simple setae dorsally, ventrally with 2 parallel rows of setae, every row with 12 groups of setae and arranged in groups of 1 long filtering and 1 shorter simple seta; propodus about 0.9 times carpus length, 7.8 times longer than wide, with 2 moderate setae and 3 small simple setae dorsally, ventrally with 2 parallel rows of setae, every row with 11 groups of setae and arranged in groups of 1 long filtering and 1 shorter simple seta; dactylus 0.6 times propodus length, 10.0 times longer than wide, with 4 small simple setae dorsally and ventrally; unguis 1/3 times dactylus length, with a short ventral claw and a medial seta.</p> <p>Pereopod 5 (Fig. 4 C) broken off, only basis remains, 3.4 times longer than wide, with 3 feather-like setae dorsally, dorsal and ventral surface covered with extremely dense mat of fine setae.</p> <p>Pereopods 6–7 (Figs. 4 D–E) shorter and stronger than pereopods 2–4; two distal claws, stouter and much shorter than unguis of pereopods 2, 4. Pereopod 6 (Fig. 4 D) basis longest article, 3.7 times longer than wide, with 3 feather-like setae dorsally, dorsal and ventral surface covered with extremely dense mat of fine setae; ischium 0.6 times basis length, 2.3 times longer than wide, with few simple setae ventrally, dorsal and ventral surface covered with extremely dense mat of fine setae; merus 0.6 times ischium length, 1.4 times longer than wide, dorsal and ventral surface covered with extremely dense mat of fine setae, ventral surface with 2 row of short spines, each row arranged in 4 spines; carpus 0.9 times length merus, 0.8 times longer than wide, dorsal and ventral surface covered with few setules, ventral surface with 2 row of short spines, each row arranged in 4 spines; propodus 2.6 times longer than carpus, 3.3 times longer than wide, dorsal surface covered with few fine setae, ventral surface with 1 row of 7 short spines; dactylus 0.9 times propodus length, 5.0 times longer than wide, with few simple setae and several setules dorsally and ventrally; one simple seta and unguis, secondary unguis distally.</p> <p>Pereopod 7 (Fig. 4 E) basis longest article, 2.8 times longer than wide, with 3 feather-like setae dorsally, dorsal and ventral surface covered with extremely dense mat of fine setae; ischium 0.6 times basis length, 1.6 times longer than wide, with few simple setae ventrally, dorsal and ventral surface covered with extremely dense mat of setules; merus 0.8 times ischium length, 0.6 times longer than wide, dorsal and ventral surface covered with extremely dense mat of fine setae, ventral surface with 2 row of short spines, each row arranged in 4 spines; carpus 0.9 times longer than merus, 1.6 times longer than wide, dorsal and ventral surface covered with extremely dense mat of fine setae, ventral surface with 2 row of short spines, each row arranged in 4 spines; propodus 2.7 times longer than carpus, 3.6 times longer than wide, dorsal surface covered with few setules, ventral surface with 1 row of 6 short spines; dactylus 0.8 times propodus length, 4.7 times longer than wide, with few simple setae and several setules dorsally and ventrally, one simple seta and unguis, secondary unguis distally.</p> <p>Penial plate elongate (Fig. 5 B), tapering proximally and distally, unarmed.</p> <p>Pleopod 1 (Fig. 5 C) peduncle with 11 small triangular spine-like robust setae in a row laterally, ventromedially with seven coupling setae with hooked tips; exopod 1.1 times longer than endopod, 3.4 times as long as wide, laterally and apically with long plumose setae, posterior surface with transverse groove, ending with a protrusion on distal half of lateral margin; endopod with long plumose setae laterally and apically.</p> <p>Pleopod 2 (Fig. 5 D) exopod about as long as endopod, with long plumose setae laterally and apically; endopod of about same width as exopod, with long plumose setae laterally and apically; stiletto-like appendix masculina 1.1 times as long as endopod, with acute apex.</p> <p>Pleopod 3 (Fig. 5 E) exopod 1.2 times longer than endopod, setae absent; endopod of about same width as exopod, with a long and slender setae distolaterally.</p> <p>Pleopod 4 (Fig. 5 F) exopod 1.1 times longer than endopod, setae absent; endopod of about same width as exopod, with few simple setae laterally and 4 long and slender setae distolaterally.</p> <p>Pleopod 5 (Fig. 5 G) exopod 1.1 times longer than endopod, setae absent; endopod of about same width as exopod, with few simple setae laterally and 4 long and slender plumose setae distolaterally.</p> <p>Uropod (Fig. 5 A) biramous, peduncle with 14 long plumose setae on distolateral margin and a small triangular spine distally, surface laterally unarmed; exopod broader than linear endopod, about 1.3 times as long as endopod, unarmed distally; endopod with 3 simple setae distally.</p> <p> <b>Etymology.</b> The species name is derived from the oceanographic vessel “ <i>Kexue”</i> of Institute of Oceanology, Chinese Academy of Sciences, which contributed substantially to biological studies of Okinawa Trough.</p> <p> <b>Distribution and habitat.</b> Only known from type locality (Okinawa Trough, East China Sea, 2115 m).</p> <p> <b>Remarks.</b> The present new species is assigned to <i>Litarcturus</i> because of the following characters: with the tendency to reduce cuticular spines on the whole body surface; cephalothorax with one pair of supraocular spines, in some cases reduced or very small; caudal pleotelsonic spines comparatively short.</p> <p> <i>Litarcturus kexueiae</i> <b>sp. nov.</b> belongs to the third group with <i>L. granulosus</i> (Nordenstam, 1933) and <i>L. stebbingi</i> (Beddard, 1886), with supraocular and caudal pleotelsonic spines. However, <i>L. kexueiae</i> <b>sp. nov.</b> differs markedly from <i>L. granulosus</i> as its supraocular spines are longer than the cephalothorax apex (versus supraocular spines not longer than the cephalothorax apex), and from <i>L. stebbingi</i> as its caudal pleotelsonic spines are longer than the pleotelson apex (versus caudal pleotelsonic spines not longer than the pleotelson apex).</p>Published as part of <i>Liu, Wenliang & Sha, Zhongli, 2015, Litarcturus kexueiae sp. nov., a new deep-sea isopod from the Okinawa Trough (Crustacea, Isopoda, Valvifera, Antarcturidae), pp. 531-540 in Zootaxa 4013 (4)</i> on pages 533-539, DOI: 10.11646/zootaxa.4013.4.4, <a href="http://zenodo.org/record/236981">http://zenodo.org/record/236981</a>
New Records in Collision Attacks on SHA-2
No full textThe SHA-2 family including SHA-224, SHA-256, SHA-384,
SHA-512, SHA-512/224 and SHA512/256 is a U.S. federal standard pub-
lished by NIST. Especially, there is no doubt that SHA-256 is one of the
most important hash functions used in real-world applications. Due to
its complex design compared with SHA-1, there is almost no progress
in collision attacks on SHA-2 after ASIACRYPT 2015. In this work, we
retake this challenge and aim to significantly improve collision attacks
on the SHA-2 family. First, we observe from many existing attacks on
SHA-2 that the current advanced tool to search for SHA-2 characteristics
has reached the bottleneck. Specifically, longer differential characteristics
could not be found, and this causes that the collision attack could not
reach more steps. To address this issue, we adopt Liu et al.’s MILP-based
method and implement it with SAT/SMT for SHA-2, where we also add
more techniques to detect contradictions in SHA-2 characteristics. This
answers an open problem left in Liu et al.’s paper to apply the technique
to SHA-2. With this SAT/SMT-based tool, we search for SHA-2 charac-
teristics by controlling its sparsity in a dedicated way. As a result, we
successfully find the first practical semi-free-start (SFS) colliding message
pair for 39-step SHA-256, improving the best 38-step SFS collision attack
published at EUROCRYPT 2013. In addition, we also report the first
practical free-start (FS) collision attack on 40-step SHA-224, while the
previously best theoretic 40-step attack has time complexity 2110. More-
over, for the first time, we can mount practical and theoretic collision
attacks on 28-step and 31-step SHA-512, respectively, which improve the
best collision attack only reaching 27 steps of SHA-512 at ASIACRYPT
2015. In a word, with new techniques to find SHA-2 characteristics, we
have made some notable progress in the analysis of SHA-2 after the major
achievements made at EUROCRYPT 2013 and ASIACRYPT 2015
Litarcturus kexueiae sp. nov., a new deep-sea isopod from the Okinawa Trough (Crustacea, Isopoda, Valvifera, Antarcturidae)
No full textLiu, Wenliang, Sha, Zhongli (2015): Litarcturus kexueiae sp. nov., a new deep-sea isopod from the Okinawa Trough (Crustacea, Isopoda, Valvifera, Antarcturidae). Zootaxa 4013 (4): 531-540, DOI: 10.11646/zootaxa.4013.4.
FIGURE 4 in Litarcturus kexueiae sp. nov., a new deep-sea isopod from the Okinawa Trough (Crustacea, Isopoda, Valvifera, Antarcturidae)
No full textFIGURE 4. Litarcturus kexueiae sp. nov. A–E, holotype male (MBM240861). A–E, pereopods 3–7 (A, pereopod 3 propodus broken off; C, pereopod 5 only basis remains). Scale bars = 1 mm.Published as part of Liu, Wenliang & Sha, Zhongli, 2015, Litarcturus kexueiae sp. nov., a new deep-sea isopod from the Okinawa Trough (Crustacea, Isopoda, Valvifera, Antarcturidae), pp. 531-540 in Zootaxa 4013 (4) on page 537, DOI: 10.11646/zootaxa.4013.4.4, http://zenodo.org/record/23698
Promalactis serrata , Du, Li & Wang 2011
No full textPromalactis serrata Du, Li & Wang, 2011 (Figs. 8, 19) Promalactis serrata Du, Li & Wang, 2011, Zootaxa, 3044: 60. TL: China (Hainan). Material examined. CHINA, Hainan Island: 3♂, 1♀, Jianfengling Nature Reserves, 770 m, 15–17.VII.2014, coll. Peixin Cong, Linjie Liu & Sha Hu, slide Nos. HS 14037 ♂, HS14114 ♀, HS14116 ♂; 4♂, Jianfengling Nature Reserves, 770 m, 3.VI.2014, coll. Peixin Cong, Wei Guan & Sha Hu, slide No. HS 15193 ♂; 1♀, Wuzhishan Nature Reserves, 710 m, 21.IV.2014, coll. Tengteng Liu, Wei Guan & Sha Hu, slide No. HS 14117 ♀; 1♀, Limushan Forest Park (19.17°N, 109.73°E), 607 m, 25.VII.2014, coll. Peixin Cong, Linjie Liu & Sha Hu, slide No. HS 14121 ♀; 1♂, Baisha County, 460 m, 1.VII.2014, coll. Peixin Cong, Linjie Liu & Sha Hu, slide No. HS 14097 ♂; 1♀, Hongkan, Yinggeling, 540 m, 15.VIII.2016, coll. Qingyun Wang, Suran Li & Shengnan Zhao, slide No. HS 16026 ♀; 1♀, Wushan Nature Reserves, 742 m, 18.V.2015, coll. Peixin Cong, Sha Hu & Wei Guan, slide No. HS 15227 ♀; 1♀, Wuzhishan National Park, 766m, 11.I.2016, slide No. HS 16022 ♀. Description of female genitalia (Fig. 19): Apophyses anteriores about 3/5 length of apophyses posteriores. Lamella antevaginalis large triangular, with slender longitudinal carinae near lateral side distally; lamella postvaginalis quadrate in basal half, elliptic in distal half. Antrum funneled, heavily sclerotized. Ductus bursae membranous for short distance near antrum and towards corpus bursae distally, remaining part heavily sclerotized, curved, with stout spines in basal half. Corpus bursae sub-rounded; signum absent. Distribution. China (Hainan). Note. The female of this species is described for the first time.Published as part of Hu, Sha & Wang, Shuxia, 2017, Taxonomic study of the genus Promalactis Meyrick (Lepidoptera, Oecophoridae) from Hainan Island, China (III), pp. 590-600 in Zootaxa 4303 (4) on pages 597-598, DOI: 10.11646/zootaxa.4303.4.9, http://zenodo.org/record/84158
Where and about what? Price relevant narratives depend on topic and media type
No full textThe role of traditional or social media-expressed tone on stock prices is nuanced. Negative tone of traditional media articles is much more likely to convey material information than web messages. Some topics, regardless of source, are unusually negative, causing fluctuations in investor sentiment and temporary price deviations
New Records in Collision Attacks on RIPEMD-160 and SHA-256
No full textRIPEMD-160 and SHA-256 are two hash functions used to generate the bitcoin address. In particular, RIPEMD-160 is an ISO/IEC standard and SHA-256 has been widely used in the world. Due to their complex designs, the progress to find (semi-free-start) collisions for the two hash functions is slow. Recently at EUROCRYPT 2023, Liu et al. presented the first collision attack on 36 steps of RIPEMD-160 and the first MILP-based method to find collision-generating signed differential characteristics. We continue this line of research and implement the MILP-based method with a SAT/SMT-based method. Furthermore, we observe that the collision attack on RIPEMD-160 can be improved to 40 steps with different message differences. We have practically found a colliding message pair for 40-step RIPEMD-160 in 16 hours with 115 threads. Moreover, we also report the first semi-free-start (SFS) colliding message pair for 39-step SHA-256, which can be found in about 3 hours with 120 threads. These results update the best (SFS) collision attacks on RIPEMD-160 and SHA-256. Especially, we have made some progress on SHA-256 since the last update on (SFS) collision attacks on it at EUROCRYPT 2013, where the first practical SFS collision attack on 38-step SHA-256 was found
Litarcturus Brandt 1990
No full textGenus <i>Litarcturus</i> Brandt, 1990 <p> <i>Litarcturus</i> Brandt, 1990: 88 –89; Poore, 2001: 224; Poore, 2015: 14.</p>Published as part of <i>Liu, Wenliang & Sha, Zhongli, 2015, Litarcturus kexueiae sp. nov., a new deep-sea isopod from the Okinawa Trough (Crustacea, Isopoda, Valvifera, Antarcturidae), pp. 531-540 in Zootaxa 4013 (4)</i> on page 531, DOI: 10.11646/zootaxa.4013.4.4, <a href="http://zenodo.org/record/236981">http://zenodo.org/record/236981</a>
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