Metal Spikes Research Articles

Chlamydial infections in feral pigeons in Europe: Review of data and focus on public health implications

Feral pigeons ( Columba livia domestica), which thrive in most European towns and cities, are commonly infected with the zoonotic bacterium Chlamydophila psittaci, the agent of psittacosis (also known as ornithosis) in humans. A number of surveys carried out over the last thirty years across Europe have detected high seropositivity values and high percentages of infection in feral pigeon populations. Overall, when considering data from 11 European countries, seropositivity values to C. psittaci in the sampled populations ranged from 19.4% to 95.6%. In most surveys, the complement fixation test was used, and antibodies were detected in 19.4–66.3% of the samples, with a median of 46.1%. Indirect immunofluorescence and ELISA tests were employed less frequently, but led to the detection of higher percentages of seropositivity (23.7–67.7% and 35.9–95.6%, respectively). Attempts to grow C. psittaci in cell culture or embryonated chicken eggs were successful in 2–42.3% and 0–57.1% of samples, respectively, antigen detection methods were positive in 2.3–40% of samples, while conventional PCR and real-time PCR using different genomic targets detected the organism in 3.4–50% of samples. Twenty-five C. psittaci isolates from pigeons were typed as ompA genotype B ( n = 14), E ( n = 10) and E/B ( n = 1). The huge increase of feral pigeon populations in Europe is a major cause of concern for the detrimental effect of pigeon droppings on environmental hygiene, in addition to the extensive damage due to the fouling of buildings and monuments. The most important pathogenic organism transmissible from feral pigeons to humans is C. psittaci, with 101 cases of disease reported in the literature. Exposure to C. psittaci-contaminated dust, direct contact with pigeons through handling and, to a lesser extent, through pigeon feeding have been identified as hazardous exposures in more than half of the human cases, while loose or transient contacts with feral pigeons have been mentioned in about 40% of the cases. Education initiatives as to the communication of a health risk resulting from contact with pigeons and pigeon excreta should primarily be targeted at individuals who may be exposed to C. psittaci-contaminated dust, such as demolition/construction workers. Recommendations to this category of workers include wearing protective clothes with hoods, boots, gloves and air filter face masks when removing pigeon faeces from roofs, garrets and buildings, especially if working indoors. Monitoring for C. psittaci infections in these workers over time should also be considered. Children should be warned not to handle sick or dead pigeons, and immunocompromised individuals should be advised to carefully limit their contact to feral pigeons. Culling of pigeons by shooting or poisoning is both unethical and ineffective as the place of the killed birds in the population is quickly filled by new juveniles or immigrating birds from neighbouring areas. Pigeon-deterring systems, such as nets and plastic or metal spikes applied to buildings and monuments will prevent their fouling, and the administration of contraceptive drugs may allow size regulation of the pigeon populations. Nevertheless, the measure that will ultimately lead to permanent reduction and will establish healthy sustainable populations is the restriction of indiscriminate feeding by pigeon lovers. The erection of dovecotes and artificial breeding facilities should be considered for providing shelter and a balanced diet to the birds, as well as a chance of interaction for pigeon lovers in a hygienically controlled environment.

What a Hot Comb Can Tell Us about History: Material Culture and the Classroom

The object being passed around the classroom attracts the keen interest of my students. Long and thin, it spans almost ten inches from end to end but measures just over an inch at its fat test. The head of the object, which is about three and a quarter inches long, is made of gold colored metal. One side of the head is solid and rounded, and the other has thirty-three thin metal spikes that stick out about three-quarters of an inch and taper to a sharp point. They are even and orderly, each spaced precisely one-sixteenth of an inch apart from the next. The metal head rests snugly on a one-inch metal pole, also gold colored, which itself fits into a silver metal cap. The cap is rounded on top, curves in around the short pole, and fits tightly against a black laminated wood shaft. The rounded shaft

Preventive Measures to Reduce Bird Related Power Outages—Part II: Streamers and Contamination

Bird related outages are more common and widespread than generally believed. The objective of this paper is to review the existing bird related problems and to recommend practices and procedures that are successful in reducing bird related outages on transmission lines, in substations and on overhead distribution lines. Experience has shown that use of perch guards, metal or plastic spikes, insulating caps, alternate perch sites and washing have significantly reduced bird related streamer and contamination outages.

Anomalous current–voltage characteristics of thin polymer films

In this paper we have investigated organic light emitting diodes with such electroluminescent materials as aromatic polyimide, poly∼N-vinylcarbazole (PVK) and dye doped PVK. N-type current–voltage characteristics with negative differential resistance for the thin polymeric and organic films are analyzed. No reasonable explanation has been provided for this phenomenon until now. Here we suggest that a polymer(organic)/metal interface containing various inhomogeneities and metal spikes is responsible for this effect. We detect also the black-body radiation, whose temperature exceeds both the melting point and the sublimation temperature of the metal of the electrode. We suppose that the current density through the spike in any cases is large enough to cause the explosion of the tip of the spike and the detected radiation has the hot plasma origin. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Seeking the Language of Solid Ground: Reflections on Ecocriticism and Narrative

Seeking the Language of Solid Ground: Reflections on Ecocriticism and Narrative Scott Slovic Seldom does the faUen climber survive to teU his or her own tale. A few years ago, overburdened by a backpack fuU of books and distracted by my professional role as textual critic, I ignored my place in the physical world, stepped off a mountain wall, and nearly lost my life and my voice as a scholar. Ecocritics, in forgetting the worldly context oftheir reading , of their thinking, do so at the peril of their own language. Language without context, without grounding in the world, means next to nothing. At the end of July 1995, a group of eight traveled to the Shirakami Mountains in northwestern Honshu, a United NationsWorld Heritage Site, to do a story on wilderness protection in Japan for Audubon magazine.1 Three of us—nature writer Rick Bass, photographer Mike Yamashita, and I—had come from the United States for this excursion. Translator and nature writer Bruce AUen, editor Nobuhiro Sato, and environmental journalist Shigeyuki Okajimajoined us inTokyo for the flight north to Aomori. Our guides were Makoto Nebuka, a prolific outdoor writer and the principal defender of the Shirakami wilderness, and one of his mountain-man friends, known to us only as "Narita-san." We were an all-male group. Hisako Tanaka, an editor for the popular Japanese nature magazine called Shinra, had flown up separately from Tokyo just to interview Rick during the limo ride to the trailhead; she hiked with us for an hour on a paved path to see a few picturesque waterfaUs, but when the rest ofus left the trail and began dragging ourselves on hands and knees up a sheer, overgrown ridge, she smiled and waved goodbye. We hadn't expected such rugged conditions. For three days in the virgin beech forests of Shirakami, we worked our way up rivers in special hiking An earlier version of this essay was prepared as a position paperfor the roundtable titled "Narrative Scholarship: Storytelling in Ecocriticism" at the Western Literature Association Conference in Vancouver, British Columbia, October 11-14, 1995. 34 Scott Slovic35 shoes caUed "chicatabi" with rubber cushions and metal spikes on the bottom , cUmbed smaU waterfaUs, and crawled up steep mountainsides with scraggly trees and bamboo-like sasa grass, interwoven with poison ivy, as handholds. These forests were traiUess, except for occasional deer paths. I found myselfpreoccupied with the other writers on the trip and the efforts of Mike, the photographer, to document the place and the people wtdle struggUng to keep up with Nebuka-san's steady pace. The expedition was like a hall of mirrors—everyone was watching, interviewing, keeping a notebook . I was fascinated with Rick's abiUty to take notes on a pocket-sized pad even while wobbhng across rivers or while pausing on a taxing slope. Occasionally, he would say something aloud like, "So many images oflight. SunUght, bright-colored frogs, light on water, Ught through leaves" or "The strands ofthe story break apart and reweave themselves—first bears, then the Shirakami Preserve, and now Nebuka-san himselfis emerging as the center." My own notebook reflects Rick's comments more than the place itself. At the end of our second day in the mountains, after ten hours of grueling travel, our guides became disoriented just as it began to get dark; we clambered and fought our way downhiU through a dense thicket of sasa grass, foUowing an apparent animal trail, until we found ourselves looking over the dribbling lip of a narrow waterfall—two hundred feet down. We paused there for another half-hour—Rick took notes and I took notes about his notetaking, and photographs—as our guides deliberated. The guides figured we could inch our way across the top of the waterfall and along the sheer slope to one side, then climb down to a possible campsite. Back and forth they crawled, scouting out the route. I continued watching Rick and bantering with the others. Then it was my turn to go. I was the second person to foUow the guides, trying to secure myselfby holding slender sasa stalks and using my spiked shoes to grip the grassy lip on the...

Bone-Graft Surgery

Bone-Graft Surgery

Metal spikes for incinerator and BIF compliance test and trial burn

This paper presents a discussion of the various chemical and physical forms of metal compounds that may be used for spiking during the trial burn or compliance test for hazardous waste combustion systems. It discusses the factors which should be considered in selecting the forms of the spiking metals for organic (hot, high Btu, or high heating value) waste streams, aqueous waste streams, and solid waste streams. The paper focuses on the organic waste streams and compares the use of organic metal dispersion to the use of organometal compounds or aqueous solutions of metal compounds as spikes for these types of feed streams. It is concluded that metal dispersions appear to form particulate which is in the appropriate micron range to tax the air pollution control system's performance. Dispersions of all regulated metals are commercially available in the required quantities for each application and they are relatively easy to pump, and to meter. Dispersions can be formulated so that their heating values are high enough to maintain the required elevated combustion and flame temperatures, and they are representative of the most common types of metal-bearing wastes sent to incinerators. The dispersions can also be used to spike metal compounds into water-based waste streams.

Studies on metal/benzocyclobutene (BCB) interface and adhesion

Interfacial characteristics such as chemical reaction, metal diffusion, and morphology were investigated for Cu/BCB, Cr/BCB and Ti/BCB structures. Using Auger and XPS depth profiling, the formation of titanium carbide and chromium oxide was confirmed at the metal/BCB interface. Annealing at 250°C for extended periods resulted in the diffusion of Cu, Cr and Ti into the BCB and subsequent formation of Cu-Si, CrSi2 and Ti-Si compound precipitates. The reaction is a thermal diffusion controlled process which is dependent on time and temperature. Ar sputtering treatment of BCB film before metallization was found to roughen the surface, resulting in metal spikes which penetrate into the roughened BCB film. However, the peel strength of metals on BCB was only about 177 g cm_1presumably due to the brittleness of the BCB film. The etch rates of the BCB film in a reactive ion etcher (RIE) and a plasma etcher were measured using Ar, O2, O2 + CF4, and O2 + SF6 gas mixtures. Faster etch rates were obtained when CF4 and SF6 were added to oxygen, since the presence of atomic fluorine enhances the etch rate of organics, while also etching Si and SiO2 formed by exposure of Si-containing BCB film to oxygen gas. Surface compositional changes on the BCB film were observed by XPS after plasma modification. Pure O2 and O2 + CF4 plasmas oxidized the carbo-siloxane linkage (C—Si—O) of the BCB, resulting in the formation of SiO2 on the surface. The O2 + SF6 plasma, however, did not produce the surface SiO2, because of its faster Si and SiO2 etch rates.

Interfacial Studies on Cr and Ti Deposited on Benzocyclobutene (BCB) Film

ABSTRACTInterfacial characteristics such as chemical reaction, metal diffusion, and morphology were investigated for Cr/BCB and Ti/BCB structures. Using Auger and XPS depth profiling, the formation of Ti carbide and Cr oxide was confirmed at the metal/BCB interface. Annealing at 250 °C for extended time periods resulted in diffusion of Cr and Ti into the BCB and subsequent formation of CrSi2and Ti-Si compound precipitates. The reaction is a thermal diffusion controlled process which was dependent on time and temperature. It was also found that Ar backsputtering treatment on BCB film before metallization was found to roughen the surface resulting in metal spikes which penetrate into the BCB film.

Mass spectrometic isotope dilution analysis of Am and Cm

Spent nuclear fuels contain Am and Cm in the 10 ppb to 100 ppm range. Because of this low abundance and the necessity of handling small samples of the highly toxic fuel material only a mass-spectrometric isotope dilution analysis can give sufficiently accurate results. Since suitable spikes and/or standards have been lacking, this method has not been applied. Using known masses (± 0.1%) of Am-241 and Cm-244 metal, Am-243 and Cm-248 spikes were calibrated to an accuracy of better than 0.2 %. The standards were reanalysed by chemical titration and several radiometric techniques. The chemical conditioning is based on ionexchange chromatography with α-hydroxyisobutyric acid. A sample size of 10 −7 g is sufficient. For the mass-spectrometric measurement 10 −9 g of the elements are required. The accuracy for the determination of the main isotope is 0.5 %.

Metal transfer during vacuum consumable arc remelting

An investigation was conducted to determine how metal is transferred during vacuum consumable arc remelting. The transfer mode was found to be dependent on arc length for the electrode sizes (0.10 to 0.20 m diam) and electrical parameters studied (1.9 to 3 kA and 25 V). At short arc lengths ≤0.03 m, metal transfer was found to occur when liquid metal spikes hanging from the cathode form a low resistance bridge (drop short) by touching the anode and then subsequently rupture. The formation and rupture of these molten metal bridges was confirmed with electrical resistance measurements. During the bridge lifetime (0.0003 to 0.020 s) the arc was extinguished and all of the electrical power was directed through the molten bridge. At long arc lengths (>0.1 m) the spikes separate before touching the anode. Experimental observations concerning the coalescence of molten material at the cathode tip were made and they were found to be in agreement with theories on liquid instabilities. A review of pertinent literature concerning vacuum arcs was conducted and this along with general information on vacuum consumable arc re-melting are included as background information.

Tunnelling through thin adsorbed films in ion discharge at limiting current—I. Potential barriers and analytic equations

The shape of potential barriers and the basic equations of the tunnelling limiting current are established for the following interfaces: metal/electrolyte, metal/thin-dielectric-film/electrolyte and metal/thin-semiconductor-film/electrolyte. The occurrence of the thin adsorbed films explains well the formation and the isolation of the metal dendrites at the dme. Owing to the very large number of electrons striking the inner metal surface, the tunnelling thickness in solution seems to be greater than 10 Å, while the tunnelling thickness in solid films are generally considered to be of the order of 10–100 Å. A general mechanism for electrolytic metal powder formation is proposed, taking into account electron tunnelling through thin solid films and at the metal/electrolyte interface. An important role is attributed to the formation of metal spikes.

Closure of Boxing Lacerations Between Rounds

Over the ages the manly art of self-defense has been tempered and the chances of injury to contestants reduced not only by the change from metal spikes to bare knuckles and finally padded gloves, but by the Queensbury and World Boxing Association rules. Further measures are in order. Far greater care must be used to eliminate unfit fighters from the ring. This should not be left to the judgment of the manager. Often a boxer is suffering from the effects of the previous fight or the subtle summation of blows during many fights. It is always better that he be forced to hang up his gloves before it is too late. A fighter known to take punishment like a Paret must be under closer scrutiny than a Willie the Wisp who seldom absorbs a direct blow. The greatest danger is during the contest when a boxer temporarily out on his

Rapid vacuum freeze‐drying of meat

AbstractFreeze‐drying carried out in conventional equipment is a slow process, the rate of drying being limited by the rate of transfer of heat of sublimation. A method is described to carry out rapid freeze‐drying of meat or other foodstuffs by laying the pieces between heater plates fitted with metal spikes which conduct heat uniformly and efficiently into the material. Meat slices 3/4 in. thick can be freeze‐dried in 3–5 hours.