3,008 research outputs found
A revision of the Sclerocoelus galapagensis group (Diptera: Sphaeroceridae: Limosininae)
The Sclerocoelus galapagensis group is defined and revised, including the description of S. galapagensis new species from the Galapagos Islands; S. caribensis new species from the Caribbean and adjacent areas; S. brasilensis new species from Brazil, Ecuador, Colombia, and Panama; S. hemorrhoidal is new species from Ecuador and Venezuela; and S. andensis new species from Argentina, Bolivia, and Venezuela. The south Atlantic species Sclerocoelus subbrevipennis (Frey), new combination, is redescribed as a member of the S. galapagensis group, and is considered the sister species to the rest of the species group. A key to species, character matrix, and cladogram are provided
Medical image enhancement using threshold decomposition driven adaptive morphological filter
One of the most common degradations in medical images is their poor contrast quality. This suggests the use of contrast enhancement methods as an attempt to modify the intensity distribution of the image. In this paper, a new edge detected morphological filter is proposed to sharpen digital medical images. This is done by detecting the positions of the edges and then applying a class of morphological filtering. Motivated by the success of threshold decomposition, gradientbased operators are used to detect the locations of the edges. A morphological filter is used to sharpen these detected edges. Experimental results demonstrate that the detected edge deblurring filter improved the visibility and perceptibility of various embedded structures in digital medical images. Moreover, the performance of the proposed filter is superior to that of other sharpener-type filters
Revision of the New World Heteromeringia (Diptera: Clusiidae: Clusiodinae).
Die 18 neuweltlichen Arten von Heteromeringia Czerny, 1903 werden revidiert inklusive Beschreibung von 10 neuen Arten (H. apholis sp. n. (Mexiko), H. aphotisma sp. n. (Brasilien), H. decora sp. n. (Mexiko), H. lateralis sp. n. (Costa Rica), H. mediana sp. n. (Brasilien), H. nanella sp. n. (Brasilien), H. nervosa sp. n. (Costa Rica), H. quadriseta sp. n. (Ecuador, Peru), H. volcana sp. n. (Costa Rica) und H. zophina sp. n. (Mexiko)). Die nearktische Unterart H. nitida nigripes Melander & Argo, 1924 wird zur Art erhoben. Die H. nitida-Artengruppe und die H. czernyi-Artengruppe werden aufgestellt, und die Verwandtschaftsverhältnisse der letzteren (ausschließlich neotropischen) Gruppe werden diskutiert. Sobarocephala subfasciata Curran, 1939 wird synonymisiert mit H. czernyi Kertesz, 1903. Heteromeringia dimidiata Hennig, 1938 wird in die Gattung Sobarocephala Czerny, 1903 comb. n. gestellt. Heteromeringia tephrinos nomen nov. wird als Ersatzname vorgeschlagen für die afrotropische H. nigrifrons Lamb, 1914, ein jüngeres primäres Homonym von H. nigrifrons Kertesz, 1903. Die Biologie von Heteromeringia wird diskutiert und ein Bestimmungsschlüssel für die neuweltlichen Arten wird vorgestellt. Zum ersten Mal wird aggressives Verhalten innerhalb der Gattung beschrieben: Männchen von H. nitida benutzen ihre zweifarbigen Vorderbeine zur Verteidigung von Paarungsrevieren.StichwörterHeteromeringia, H. czernyi species group, H. nitida species group, Clusiidae, Diptera, New World, revision, new species, stat. n., syn. n., comb. n., nomen n., biology, behaviour.Nomenklatorische Handlungenapholis Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.aphotisma Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.decora Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.flavipes (Williston, 1896) (Heteromeringia), Lectotype described as Heteroneura flavipeslateralis Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.mediana Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.nanella Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.nervosa Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.nigripes Melander & Argo, 1924 (Heteromeringia), stat. n. described as Heteromeringia nitida var. nigripesquadriseta Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.tephrinos Lonsdale & Marshall, 2007 (Heteromeringia), nom. n. pro Heteromeringia nigrifrons Lamb, 1914, nec Kertesz, 1903volcana Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.zophina Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.dimidiata (Hennig, 1938) (Sobarocephala), comb. n. hitherto Heteromeringia dimidiatasubfasciata Curran, 1939 (Sobarocephala), syn. n. of Heteromeringia czernyi Kertesz, 1903The 18 New World species of Heteromeringia Czerny, 1903 are revised, with 10 species described as new: H. apholis sp. n. (Mexico), H. aphotisma sp. n. (Brazil), H. decora sp. n. (Mexico), H. lateralis sp. n. (Costa Rica), H. mediana sp. n. (Brazil), H. nanella sp. n. (Brazil), H. nervosa sp. n. (Costa Rica), H. quadriseta sp. n. (Ecuador, Peru), H. volcana sp. n. (Costa Rica) and H. zophina sp. n. (Mexico). The Nearctic H. nitida nigripes Melander & Argo, 1924 is raised from subspecies to species. The H. nitida species group and the H. czernyi species group are erected, and species relationships are discussed for the latter (entirely neotropical) group. Sobarocephala subfasciata Curran, 1939 is included as a junior synonym of H. czernyi Kertesz, 1903. Heteromeringia dimidiata Hennig, 1938 is moved to Sobarocephala Czerny, 1903 comb. n. Heteromeringia tephrinos nomen n. is provided as a replacement name for the Afrotropical H. nigrifrons Lamb, 1914, which is a junior primary homonym of H. nigrifrons Kertesz, 1903. The biology of Heteromeringia is discussed, and a key is provided for all New World species. Agonistic interactions are described for this genus for the first time, with H. nitida Johnson, 1913 males recorded as using bicoloured forelegs to defend mating territories.KeywordsHeteromeringia, H. czernyi species group, H. nitida species group, Clusiidae, Diptera, New World, revision, new species, stat. n., syn. n., comb. n., nomen n., biology, behaviour.Nomenclatural Actsapholis Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.aphotisma Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.decora Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.flavipes (Williston, 1896) (Heteromeringia), Lectotype described as Heteroneura flavipeslateralis Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.mediana Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.nanella Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.nervosa Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.nigripes Melander & Argo, 1924 (Heteromeringia), stat. n. described as Heteromeringia nitida var. nigripesquadriseta Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.tephrinos Lonsdale & Marshall, 2007 (Heteromeringia), nom. n. pro Heteromeringia nigrifrons Lamb, 1914, nec Kertesz, 1903volcana Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.zophina Lonsdale & Marshall, 2007 (Heteromeringia), spec. n.dimidiata (Hennig, 1938) (Sobarocephala), comb. n. hitherto Heteromeringia dimidiatasubfasciata Curran, 1939 (Sobarocephala), syn. n. of Heteromeringia czernyi Kertesz, 190
Sclerocoelus and Druciatus, new genera of New World Sphaeroceridae (Diptera; Sphaeroceridae; Limosininae)
The new genus Sclerocoelus is described for a large group of New World species including Sclerocoelus sordipes (Adams) new combination, Sclerocoelus regularis (Malloch) new combination, Sclerocoelus plumiseta (Duda) new combination, and about 40 undescribed species. The widespread Nearctic species Limosina sordipes Adams is redescribed and designated as the type species of Sclerocoelus. Lectotypes are designated for Limosina sordipes Adams and Limosina evanescens Tucker. The new genus Druciatus is described for a group of 7 undescribed species fiom Central America, South America, and the Caribbean. The type species, Druciatus ovisternus n.sp., is described from Dominica and the Dominican Republic
Design Rules and Analysis of a Capture Mechanism for Rendezvous between a Space Tether and Payload
Momentum-exchange/electrodynamic reboost (MXER) tether systems have been proposed to serve as an "upper stage in space". A MXER tether station would boost spacecraft from low Earth orbit to a high-energy orbit quickly, like a high-thrust rocket. Then, it would slowly rebuild its orbital momentum through electrodynamic thrust, minimizing the use of propellant. One of the primary challenges in developing a momentum-exchange/electrodynamic reboost tether system as identified by the 2003 MXER Technology Assessment Group is in the development of a mechanism that will enable the processes of capture, carry and release of a payload by the rotating tether as required by the MXER tether approach. This paper will present a concept that will achieve the desired goals of the capture system. This solution is presented as a multi-DOF (degree-of-freedom) capture mechanism with nearly passive operation that features matching of the capture space and expected window of capture error, efficient use of mass and nearly passive actuation during the capture process. This paper will describe the proposed capture mechanism concept and provide an evaluation of the concept through a dynamic model and experimental tests performed on a prototype article of the mechanism in a dynamically similar environment. This paper will also develop a set of rules to guide the design of such a capture mechanism based on analytical and experimental analyses. The primary contributions of this paper will be a description of the proposed capture mechanism concept, a collection of rules to guide its design, and empirical and model information that can be used to evaluate the capability of the concep
Seven new species of Druciatus Marshall (Diptera; Sphaeroceridae; Limosininae)
Druciatus nigritarsus new species is described from St. Vincent, Guyana, Ecuador and Peru, D. trisetus new species is described from Ecuador, Brazil and Guyana, D. dissidens and D. latisternus new species are described from Costa Rica, D. angustus new species is described from Mexico, D. campbelli new species is described from Guatemala, and D. petilus new species is described from Ecuador. A key is provided to the eight species in the genus Druciatus
A review of Minilimosina (Svarciella) Rohácek, with descriptions of fourteen new species (Diptera: Sphaeroceridae)
A worldwide review of Minilimosina (Svarciella) Rohacek 1983, comprising 27 species, is provided, with data about the primary types, published descriptions and figures, synonyms and distribution including new records
Arctic Ice Export Events and Their Potential Impact on Global Climate During the Late Pleistocene
Ice sheets in the North American Arctic and, to a lesser extent, those in northern Eurasia calved large quantities of icebergs that drifted through Fram Strait into the Greenland Sea several times during the late Pleistocene. These icebergs deposited Fe oxide grains (45-250 mum) and coarse lithic clasts \u3e250 mum matched to specific circum-Arctic sources. Four massive Arctic iceberg export events are identified from the Laurentide and the Innuitian ice sheets, between 14 and 34 ka (calendar years) in a sediment core from Fram Strait. These relatively short duration (\u3c1-4 kyr) events contain 3-5 times the background levels of Fe oxide grains. They began suddenly, as indicated by a steep rise in the number of grains matched to an ice sheet source, suggesting rapid purges of ice through Fram Strait, due perhaps to collapse of ice sheets. The larger events from the northwestern Laurentide ice sheet are preceded by events from the Innuitian ice sheet. Despite the chronological uncertainties, the Arctic export events appear to occur prior to Heinrich events
Exploration of the effects of classroom humidity levels on teachers’ respiratory symptoms
Previous studies indicate that teachers have higher asthma prevalence than other non-industrial worker groups. Schools frequently have trouble maintaining indoor relative humidity (RH) within the optimum range (30-50%) for reducing allergens and irritants. However, the potential relationship between classroom humidity and teachers’ health has not been explored. Thus, we examined the relationship between classroom humidity levels and respiratory symptoms among North Carolina teachers
Laboratory Method to Estimate Rain-Induced Splitting in Cultivated Blueberries
Preharvest rainfall that occurs when fruit are fully ripe or approaching full ripeness can result in detrimental fruit splitting in rabbiteye and southern highbush blueberries. This study was initiated to develop a laboratory method to model rain-related incidence of splitting in cultivated blueberries with the goal of predicting the incidence of splitting in blueberry cultivars and selections. Multiyear field surveys of rabbiteye and southern highbush cultivars show that the incidence of rain-related splitting is strongly cultivar-dependent. Laboratory values for forced splitting and naturally occurring rain-related field splitting data show a strong correlation indicating that the incidence of fruit splitting can be accurately estimated by this laboratory method. Soaking the berries in distilled water 14 h at room temperature gives a confident determination of splitting tendencies. Blueberry breeders and geneticists can use this method to evaluate new potential blueberry cultivars for splitting tendencies as part of routine screening. This would lead to a long-term goal of reducing splitting susceptible blueberry cultivars in commercial plantings
- …