21,765 research outputs found
Recent Results From the EU POF-PLUS Project: Multi-Gigabit Transmission Over 1 mm Core Diameter Plastic Optical Fibers
No full textRecent activity to achieve multi-gigabit transmission over 1 mm core diameter graded-index and step-index plastic optical fibers for distances up to 50 meters is reported in this paper. By employing a simple intensity-modulated direct-detection system with pulse amplitude or digital multi-tone modulation techniques, low-cost transceivers and easy to install large-core POFs, it is demonstrated that multi-gigabit transmission up to 10 Gbit/s over 1-mm core diameter POF infrastructure is feasible. The results presented in this paper were obtained in the EU FP7 POF-PLUS project, which focused on applications in different scenarios, such as in next-generation in-building residential networks and in datacom applications
Percutaneous Endoscopic Gastrostomy in Trinidad and Tobago
No full textPercutaneous endoscopic gastrostomy tube placement is rapidly becoming the preferred method of gastrostomy tube placement. We describe our experience with this procedure in nine patients. The main complications were minor and due to local infection. This report demonstrates the simplicity and safety of this technique.
La gastrostomía endoscópica percutánea en Trinidad y Tobago
MM Bartholomew, SL Mohammed, DH Williams
RESUMEN
El procedimiento endoscópico percutáneo se está convirtiendo rápidamente en el método preferido para la colocación de un tubo en la gastrostomía. Aquí describimos nuestras experiencias con este procedimiento en nueve pacientes. Las complicaciones principales fueron menores y debidas a infecciones locales. Este informe demuestra la simplicidad y seguridad de esta técnica
Re-Processing Of Gold Tailings At Ariab Area North- East Of Sudan
No full textThe main objective of this research is to extract the Gold from the tailings which
are dumped at Ariab Mines North East of Sudan by using the processing
technology. These tailings dumps amount about 2,500,000 ton and contain Gold
between (1.1-1.4)g/t,
A bulk sample about 700kg from heap No 102 was used to conduct this study. The
grade and the moisture content were determined. They are 1.28 g/t and 1.0%
respectively. The natural pH of the tailings and their particles size distribution were
also determined.
The Head Sample was subjected to comminution process. Then was divided into
three lots to give three sizes,-12.5, -5 and -0.8 mm. Each of these lots was screened
to determine its size distribution and to define the Gold distribution in its different
size fractions.
The first lot Sample showed that 45% of the distribution of the Gold is under the
size 1 mm and 55% of the distribution of the Gold is over the size 1 mm. The
Second lot Sample showed that 50% of the distribution of the Gold is under the
size 0.5 mm and 50% of the distribution of the Gold is over the size 0.5 mm. The
Third lot Sample shown that 52% of the distribution of the Gold is under the size
0.3 mm and 48% of the Gold is over the size 0.3 mm.
The results of the treatment of the three different sizes (12.5, 5 and 0.8 mm) by
leaching process with the Sodium Cyanide indicated that recoveries amount 10.78,
16.68 and 33.04 % for the sizes 12.5, 5 and 0.8 mm, respectively.
Inspection of these results would indicate that decreasing the sizes of the tailings
would increase the obtained recovery by leaching these tailings materials with
Sodium Cyanide
Mm-Wave STSK-aided single carrier block transmission for broadband networking
No full textMillimeter wave (mm-Wave) communications has been considered as a strong candidate for future wireless standards, due to the large available bandwidth in the order of gigahertz. As a result, a plethora of future services and application-oriented scenarios can be conceived, under suitable propagation conditions. Accurate physical (PHY) layer design plays a vital role in the deployment of robust transmission systems able to efficiently exploit the large bandwidth portions available in the mm-Wave frequencies. In this paper, we propose Space-Time Shift Keying (STSK) MIMO coding combined with Cyclic-Prefixed Single Carrier (CP-SC) block transmission for broadband data exchange over frequency-selective mm-Wave channels. STSK allows to exploit transmit and receive diversity with better performance when compared with state-of-the-art MIMO techniques only relying on receive diversity, such as, for example Spatial Modulation (SM). The performance of CP-SC-STSK and CP-SC-SM have been assessed in the presence of phase noise and imperfect channel estimation, considering 2 and 4 elements MIMO systems and LoS indoor vs. nLoS outdoor 73 GHz multipath channels. We show that the STSK-based solution using MMSE Frequency-Domain Equalization (FDE) is very robust against the aforementioned impairments and clearly outperforms CP-SC-SM at the price of a slight increase of receiver complexity and a throughput reduction of 50% when 4 × 4 MIMO systems are considered
Magelona heteropoda Mohammed 1973
No full text<i>Magelona heteropoda</i> Mohammed, 1973 <p>Figures 5–8</p> <p> <i>Magelona heteropoda</i> Mohammed, 1973: 39 –40, fig. 9</p> <p> <b>Material examined.</b> Abu Halifa, Kuwait, Arabian Gulf (29°08’N, 48°07’E), in sand, intertidal, Holotype (BMNH:ZB.1971.54, complete in 6 fragments), 26th September 1969, collected by Murad-B. M. Mohammed. (Note: type specimen originally described as being complete, presumably entire, although not stated), unfortunately the specimen fragmented during transit.</p> <p> <b>Description.</b> A moderately stout species; abdomen marginally wider than thorax (Fig. 5 A). Holotype, complete (however, see below), extremely fragile (body almost detached at several segments). Anterior fragment, 35.3 mm for 63 chaetigers; prostomium 1.6 mm long, 1.1 mm wide; thorax (including prostomium) 7.1 mm long, 0.8 mm wide; abdomen 0.9 mm wide; four abdominal fragments (5.2 mm for 12 chaetigers, 2.6 mm for 4 chaetigers, 1.2 mm for 2 chaetigers and 4.3 mm for 8 chaetigers); posterior fragment 3.9 mm long for 16 chaetigers; total length 52.5 mm for 106 chaetigers (originally measured as 80 mm). Note: Mohammed (1973) stated “the holotype is complete and consists of two regions: a thorax of nine setigerous segments and an abdomen of about 100 segments”, although the specimen is now fragmented it is believed to be complete. Width measurements are less than those recorded by Mohammed, although Mohammed included the parapodia within his measurements. Chaetiger 3 on both sides, chaetigers 7 and 20 on the left, and the left neuropodium of chaetiger 9 have been previously dissected (presumably by Mohammed, as these are figured in the original description).</p> <p>Prostomium elongate, much longer than wide (L:W ratio 1.45), slender triangular (less rounded and narrower than figured by Mohammed), without prostomial horns, anterior margin smooth (slightly folded over), rounded, lateral edges minutely undulating; eyes absent. Two pairs of prominent longitudinal dorsal muscular ridges, outer pair (slightly shorter) abutting inners for entire length, inner pair reaching the distal tip of prostomium, where they diverge only very slightly (Figs 5 A, 6A). Conspicuous, rounded oblong (muscular?) areas either side of ridges. Proboscis everted (not fully), heart–shaped; longitudinally ridged inferiorly, appearing smooth superiorly but with light transverse ridging (partially obscured as proboscis tip not everted). Palps arising ventrolaterally from base of prostomium, fairly robust, reaching around chaetiger 18, non–papillated region reaching chaetiger 3. Papillae short proximally, increasing in size, papillae long distally. Initially 3 rows of papillae either side of inconspicuous ventral groove, distally 2 rows.</p> <p>Peristomium achaetous, roughly twice the size of chaetiger 1. Chaetigers 1–7 similar; parapodia biramous with well–developed, thick notopodial prechaetal lamellae confluent with large delicate foliaceous postchaetal lamellae, latter of similar size throughout thorax (Figs 5 B–E). Upper edges of postchaetal lamellae lightly crenulated, a discrete notch present on fourth chaetiger (Fig. 5 C), developing into distinct bilobed lamellae by chaetiger 5 (Fig. 5 D) (note: chaetiger 3 could not be observed, but Mohammed’s original drawing of this chaetiger does not show any notch). Lateral portion of bilobed lamellae subtriangular with pointed tips, dorsalmost portions varying in shape from rounded to triangular. Single long, slender, tapering cirriform prechaetal superior process (DML) present on all thoracic chaetigers, gradually increasing in size to chaetiger 4 but decreasing towards posterior thorax.</p> <p>Neuropodia of chaetigers 1–7 with single long slender cirriform processes ventrally (VNL), directly under chaetae but becoming distinctly prechaetal by chaetiger 7, distal tips pointed. Processes becoming shorter and broader, towards posterior thorax. Pre– and postchaetal lamellae well–developed, encircling chaetae cuff–like.</p> <p>Chaetiger 8 (Fig. 5 F): Notopodial lamellae obviously bilobed, lateral portions subtriangular, dorsalmost portions triangular; apexes indented, prechaetal superior processes (DML) small. Neuropodial prechaetal processes, digitiform. Low prechaetal lamellae confluent with subtriangular postchaetal lamellae, encircling chaetae superiorly, cuff–like. Chaetae of chaetigers 1–8 simple winged capillaries.</p> <p>Chaetiger 9 (Fig. 5 A): shorter than preceding chaetigers. Notopodial prechaetal lamellae low, broadly rounded, confluent with higher postchaetal lamellae, shorter than on preceding chaetigers, upper edge distinctly crenulated (degree of crenulation varying between rami on both sides of the body, see Figs 5 G, H), lamellae encircling chaetae underneath as lateral expansions. Superior processes (DML) minute. Neuropodia similar to, but smaller than notopodia, without lateral expansions, small ventral prechaetal processes present (VML of some authors). Chaetae mucronate (not figured, in order to prevent further damage to specimen, although figured extensively by Mohammed 1973: figs 9G–L), arranged in arcs, chaetae longer towards margins of each fan.</p> <p>A conspicuous, oval swelling present ventrally, level with the lamellae of chaetiger 8 (Fig. 6 E). Additional ventral swellings observed along thorax (visible from chaetiger 3), as two oblique anterior facing structures, increasing in development along thorax; those of chaetiger 7 more developed, cordiformis (Fig. 6 E). Swellings, with sporadic white speckles. A dorsal swelling, can be observed (Fig. 5 A) between the parapodia of chaetiger 8.</p> <p>Abdominal chaetigers (Fig. 6 F) with broad, spatulate lateral lamellae, of about equal size in both rami, basally constricted, bluntly pointed. Lamellar shape shows some variation; rounded, subrectangular, oval with pointed tips. Extension of the lateral lamellae behind chaetal rows well–developed, especially in anterior abdomen, the apexes of which in some specimens form a distinct rounded tip. Small triangular processes (DML & VML) present at inner margins of chaetal rows. Lamellae of posterior fragment much reduced but initially still fairly broad, subtriangular with pointed tips, reducing to become cirriform.</p> <p> Abdominal chaetae (Fig. 6 D) tridentate hooded hooks of similar size, superior two fangs parallel, above main fang. Hooks in two groups, main fangs <i>vis–à–vis,</i> group at outer margins of chaetal rows with fewer chaetae. Initially 14 hooks per rami, decreasing to approximately 10 hooks medially and 8 (evenly distributed between both groups) posteriorly.</p> <p> Paired anteriorly open pouches between chaetigers 11 and 12 (Σ configuration of Fiege <i>et al.</i> 2000 —see discussion) as two cuticular flaps (membrane absent on both sides, presumed missing). Unpaired posteriorly open pouches (C configuration of Fiege <i>et al.</i> 2000 —see discussion) present posteriorly, on alternate chaetigers, more or less regularly. Pouches differing from previously described C configuration pouches, often quite large, expanded more dorsally and ventrally, often convoluted (Figs 7 and 8). Pouches observed on 11, 17L, 21L, 23R, 25L, 27R, 29L, 30R, 32L, 34R, 36L, 38R, 40L, 42R, 46L, 51R, 53L, 56R, 57L, 60R, 62L (on the anterior fragment), exact position of pouches difficult to discern due the fragility of the specimen. Posteriorly open pouches observed on posterior fragment (6th, 10th and 15th chaetiger from pygidium on left and the 4th, 8th and 12th on right). Pygidium rounded, left–hand anal cirri present (Figs 6 B–C), long, slender cirriform, right–hand missing (although original drawn by Mohammed).</p> <p>Specimen ovigerous, eggs appearing within the body cavity, all of a similar size. The eggs appear to be separated from the pouch by a convoluted membrane.</p> <p> <b>Colour.</b> The colouration originally described by Mohammed was uniformly white in life. The preserved material is yellowish/cream white, with darker glandular areas present inter–parapodially in the abdomen.</p> <p> Staining with methyl green shows no clear pattern, but an overall diffuse stain. However, green speckled areas associated with the ventral swellings, and dorsally in the thorax (as seen in <i>M. obockensis</i>) in particular between chaetigers 1–4 can be observed. Some staining evident abdominally between the parapodia.</p> <p> <b>Habitat.</b> Specimens found in sand, intertidally at three locations: Hawalli, Salimiyah and Abu Halifa— Kuwait, Arabian Gulf. No other records of this species have been found.</p> <p> <b>Remarks.</b> The holotype of <i>M. heteropoda</i> agrees very well with the syntypes of <i>M. obockensis</i>, in terms of prostomial shape, body size, the nature of the thoracic and abdominal lamellae, the presence of mucronate chaetae on the 9th chaetiger, the tridentate nature of the hooded hooks in two groups, and the presence of both anteriorly and posteriorly open pouches along the abdomen. However some variation between the material exists:</p> <p> Prostomium: the figured syntype of <i>M. obockensis</i> appears to have a slightly broader prostomium than that of the holotype of <i>M. heteropoda</i>. However, the figured specimen of the former species is the broadest of all observed syntypes (variation between syntypes was observed) and the prostomia of other specimens were more akin to the slightly narrower prostomium of the latter species. As well as prostomial shape, conspicuous prostomial muscular areas either side of the dorsal longitudinal ridges were observed on the holotype of <i>M. heteropoda</i>. Such areas of similar shape and size were observed on the holotype of <i>M. obockensis,</i> although not as conspicuous (Fig. 1 B). This may be explained by the age and length of preservation of the <i>M. obockensis</i> material. However, they were conspicuous in the general collection specimens of <i>M. obockensis.</i></p> <p> Palps: The palps of the holotype of <i>M. heteropoda</i>, although robust were slightly more slender than those seen in the syntype material of <i>M. obockensis</i>, with only 3 rows of papillae present either side of the groove, proximally. However, variation in the size of the palps and number of papillae was also seen between the two specimens from the general collection (MNHN A 172), possibly showing variation caused by regeneration.</p> <p> Thoracic lamellae: There is some variation in the figures of thoracic lamellae between those of <i>M. heteropoda</i> and <i>M. obockensis</i>. The upper edges appear more undulating in <i>M. obockensis</i> and smoother in <i>M. heteropoda,</i> and the nature of the bilobed lamellae (chaetiger where they first occur, and in the shape of the more dorsal portion differs a little). However, variation in lamellar shape between the syntypes of <i>M. obockensis</i> was observed (Figs 1–2), some having more rounded dorsal portions, more akin to those seen in <i>M. heteropoda</i>, becoming more triangular on later chaetigers, and a degree of variation exists in the size of the notch on preceding chaetigers. The thoracic lamellae of the broadest specimen (39 chaetiger af, both palps retained, proboscis not everted) showed bilobed lamellae from chaetiger 1.</p> <p> Chaetiger 9: the shape of the postchaetal lamellae of chaetiger 9 varies in the figures of the two species. However, the lamellar shape varies strongly between the notopodia on both sides of the body in <i>M. heteropoda</i> (Figs 5 G–H) (the variation between neuropodia could not be assessed on the holotype) and there is variation in the degree of crenulation between the syntype specimens of <i>M. obockensis</i> (Figs 1 F, 2J). Dorsal superior possesses of this chaetiger in <i>M. heteropoda</i> were minute and difficult to discern (Mohammed originally drew a minute process at the inner margin of the chaetae row), however, this was also true of several of the syntypes of <i>M. obockensis.</i></p> <p> Ventral and dorsal swellings: The presence of similar swellings on both the venter and dorsum in both species is an important characteristic. They are less well–developed in the holotype of <i>M. heteropoda</i> but are of similar size and shape, with white speckles being present on ventral swellings.</p> <p> Thoracic/abdominal junction: the junction between the two body regions in <i>M. heteropoda</i> is not as clearly marked as it is in <i>M. obockensis</i>. However, the distinction between the two body regions will often depend on the degree of body constriction upon fixation. The holotype of <i>M. heteropoda</i>, appears to have been fixed in a very elongated state (possibly due to prior relaxation?), many of the segments are weakly connected, especially in the posterior region, adding to its fragility.</p> <p> The variation seen between the two species is no more pronounced than the variation seen within the syntypes of <i>M. obockensis</i>. The morphological similarity between the two species is striking. Mohammed (1973) stated that…. “ <i>M. heteropoda</i> shows affinities with <i>M. obockensis</i>, but is readily distinguishable by its <i>bilobed</i> notopodial lamellae”, a feature now shown to be shared with <i>M. obockensis</i>. Consequently, with the corrections and additions to the original description of <i>M. obockensis</i>, I consider <i>M. heteropoda</i> to be a synonym of <i>M. obockensis.</i></p>Published as part of <i>Mortimer, Kate, 2010, Magelonidae (Polychaeta) from the Arabian Peninsula: a review of known species, with notes on Magelona tinae from Thailand, pp. 1-26 in Zootaxa 2628</i> on pages 9-14, DOI: <a href="http://zenodo.org/record/198268">10.5281/zenodo.198268</a>
Employing M1 direct calibration/de-embedding approaches for large signal model validation at mm-wave frequencies
No full textIn this contribution, we employ direct calibration/de-embedding approaches to validate the large signal device model of state-of-the-art HBTs and CMOS technologies operating in the mm-wave frequency band WR6. The capability of placing the first tier calibration reference plane in close proximity to the DUT allows the large signal metric to be directly compared with foundry models.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic
Baseband Radio over Fiber Aided Millimeter-Wave Distributed Antenna for Optical/Wireless Integration
No full textA Baseband Radio Over Fiber (BROF) architecture is proposed, where upto four Radio Frequency (RF) carriers can be generated, while using the heterodyne photo-detection of only two optical signals. This proposed BROF architecture has a star-like structure and it is composed of six Radio Access Units (RAUs), where data is transmitted from the Central Unit (CU) to the Base Station (BS) and from the BS to the RAU over a distance of 20 Km and 0.3 Km, respectively, at a rate of 768 Mbps. The performance of the system supporting four carrier frequencies drops by at most 1dB, at a BER of 10-9, compared to conventional heterodyne photo-detection
A survey of digital television broadcast transmission techniques
No full textThis paper is a survey of the transmission techniques used in digital television (TV) standards worldwide. With the increase in the demand for High-Definition (HD) TV, video-on-demand and mobile TV services, there was a real need for more bandwidth-efficient, flawless and crisp video quality, which motivated the migration from analogue to digital broadcasting. In this paper we present a brief history of the development of TV and then we survey the transmission technology used in different digital terrestrial, satellite, cable and mobile TV standards in different parts of the world. First, we present the Digital Video Broadcasting standards developed in Europe for terrestrial (DVB-T/T2), for satellite (DVB-S/S2), for cable (DVB-C) and for hand-held transmission (DVB-H). We then describe the Advanced Television System Committee standards developed in the USA both for terrestrial (ATSC) and for hand-held transmission (ATSC-M/H). We continue by describing the Integrated Services Digital Broadcasting standards developed in Japan for Terrestrial (ISDB-T) and Satellite (ISDB-S) transmission and then present the International System for Digital Television (ISDTV), which was developed in Brazil by adopting the ISDB-T physical layer architecture. Following the ISDTV, we describe the Digital Terrestrial television Multimedia Broadcast (DTMB) standard developed in China. Finally, as a design example, we highlight the physical layer implementation of the DVB-T2 standard
Dynamic Estimation of Vital Signs with mm-wave FMCW Radar
No full textIn this paper, we propose a method for continuous monitoring of vital signs-in particular, respiration frequency-with a commercial mm-wave radar. The nearly constant frequency (NCF) model is adopted to represent chest displacement due to respiration and simulate radar response. Based on this model, an extended Kalman filter (EKF) based estimator is developed to track the breathing frequency of a person. The impact of dynamic model parameters is investigated in numerical simulation. The possibility to track breathing frequency with the proposed method is demonstrated by experimental data processing. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Microwave Sensing, Signals & System
- …
