591 research outputs found
Pulmonary fibrosis of haematite miners
In summing up the results of this investigation
it is observed that the pulmonary fibrosis of haematite
miners is a recent development. There is a history
of haematite mining for several generations in this
locality without any characteristic disability and
yet within the last ten years a definite syndrome has
developed which can be recognised clinically and which
has an X..ray picture indicative of massive fibrosis.The post -mortem findings are peculiar to the
occupation for the lungs present a definite series of
characteristic changes, striking in appearance on
account of the bright red colour of the fibrosed areas.
The fibrosis is more marked in the upper lobes, is
always diffuse and is often massive in type. It originates around the bronchi and blood vessels and gives
excellent pictures of endarterit.i.s obliterans even
when not, associated with tubercle.In the fifteen post -mortems, tubercle has been
present in 66%. This is a higher percentage than is
found in silicosis which has an average of only 56%.
The experimental work confirms the general findings
that infection is a necessary factor in the production
of fibrosis and although two cases showed advanced
fibrosis with no tubercle, this just means that
tubercle is the most common infective agent, but other
low grade infections can act as well. At a recent Meeting of the 1934 Commission investigating silicosis
among coal miners, confirmation of this was found.
It was observed that in mines where the men walked to
the surface, there was only one quarter of the cases
of silicosis compared with those where the miners were
carried rapidly to the surface on trolleys. The
latter caused chilling with increased liability to
colds, bronchitis, and chronic Winter coughs with
subsequent fibrosis.Chemical analysis of the lungs revealed a high
silica content along with a phenomenally high per_
centage of iron in the ash. The ore analysed gave
only a 10% silica content but as I pointed out the
silica content of the dust whicb the men breathe is
probably much higher.The appearance of this pulmonary siderosilicosis
within recent years can only be attributed to the
change in technique in mining for the ore has not
changed chemically and the only difference is in the
increased amount of dust in the mines. The modern
method of mining with high speed percussion drills
has considerably increased the amount of dust; this
is lessened by the use of wet drills which, however,
ÂĄincrease the humidity and also increase the chance of
infection as the miners have to work in wet clothing.
The use of wet drills, while it slightly lessens the
dust, does not restore working conditions to the old
hammer and jumper standards for the increased amount of blasting and the shorter time the men are away from
the working face results in their having to work longer
in a dusty atmosphere.There can be no doubt that the disease has resulted directly from their employment and is caused
by a combination of silica and haematite, the latter
altering and aggravating the chemical action of the
former, for in itself an ore containing only 10% of
free and combined silica is not regarded as dangerous.It is considered that cases will not occur so
frequently in the future now that the causes have been
recognised, for the provision of proper ventilation
after blasting, the use of wet drills and adequate
supervision should be sufficient to ensure its prevention
Overcoming Geographical Obstacles: The Use of Skype in a Graduate-Level Social Media and Marketing Course
This paper presents the results of a three-year research and teaching effort that focused on measuring the perceived effectiveness of Skype as a delivery platform for presentations made to students enrolled in a Professional MBA program by nationally acclaimed authors working in the area of social media. The research also investigated the authorsâ acceptance of Skype as a platform for delivering remote presentations to college audiences. The results indicated that both students and authors strongly supported the use of Skype as a presentation platform. The author presentations greatly enhanced the learning environment and contributed to achieving several specific course objectives
Lead isotopic evidence for synextensional lithospheric ductile flow in the Colorado River extensional corridor, western United States
This is the published version. Copyright 1998 American Geophysical Union. All Rights Reserved.Temporal changes in the Pb isotopic compositions of Miocene lavas erupted in the northern Colorado River extensional corridor suggest that lithospheric mantle and middle to deep crust migrated from beneath the Colorado Plateau into the corridor during extension. Basaltic to rhyolitic lavas erupted in the extensional corridor prior to 12.2 Ma have Pb isotopic values that are similar to those of Tertiary to Quaternary lavas erupted through Proterozoic Mojave crust, which comprises surface exposures of basement in the corridor and much of the extended territory to the west. In contrast, most post-12.2 Ma lavas from the same region have Pb isotopic compositions similar to those of lavas erupted through Arizona crust, which forms the basement of the Colorado Plateau. The changes in isotopic compositions of the basaltic lavas, and perhaps a portion of the changes in isotopic compositions of silicic lavas, are attributed to a change in the composition of the mantle source. However, the 206Pb/204Pb ratios for lavas erupted before and after 12.2 Ma in the corridor decrease with decreasing MgO concentrations, suggesting that the Pb isotopic compositions of crustal assimilants changed at about the same time as the composition of the mantle. In the area of the Black Mountains accommodation zone, the surface boundary between the Arizona and Mojave crustal provinces lies a minimum of 60â80 km to the east of the westernmost lava with an Arizona Pb isotopic signature. This distance cannot be accounted for by displacements along nearby major faults, suggesting that middle to deep Arizona crust flowed a significant distance to the west during extension
Big Red, Ltd.
This case addresses two frequently heard questions in real-world business settings: âWhy are sales going down?â and âWhat decisions must we make to reverse the sales decline?â These questions were directed to Dr. Felix Wilder, a professor of Marketing, by the senior management of Big Red, Ltd., headquartered in Waco, Texas, after sales reports indicated a significant decline in year-over-year sales in the Louisville, Kentucky, market region. This region represented one of Big Redâs most important market areas for soft drinks outside of its home base in Texas. Members of Big Redâs senior management team were unable to identify the specific factors that had contributed to the sales decline. As a result, they commissioned Dr. Wilder to conduct an extensive marketing research project to determine the factors contributing to the erosion in sales. Dr. Wilder proposed a multifaceted exploratory research project that involved an extensive review of industry and trade literature, in-depth interviews with grocery store and super center store managers, an in-store consumer survey of Big Red customers, and a consumer focus group. The research design focused on the marketing mix variables, environmental factors, the target market, and changing consumer purchase behavior and lifestyle issues as possible sources contributing to the sales erosion. The results of Dr. Wilderâs investigation conflicted with Big Red managementâs preliminary hypotheses and revealed unexpected factors that may have contributed to the downward drift in sales. Based on the research, Dr. Wilder presented management with various alternative courses of action to correct the sales decline.
Sales Force Automation Acceptance: An Exploratory Study Of The Role Of Job Experience
User perceptions of new technologies may ultimately affect their acceptance of that technology. Recent research has identified a clear connection between user perceptions of Sales Force Automation and their acceptance of Sales Force Automation technologies. Anecdotal evidence suggests that relative to less experienced salespeople, more experienced salespeople tend to have more negative perceptions of sales force automation. This paper examines the relationship between job experience and perceptions of a sales force automation system. The results are based on a survey of 1,657 salespeople about their perceptions of several aspects of a sales force automation system in a large sales organization. This study finds significant differences by sales experience in areas such as perceived productivity/efficiency gain, perception of sales force automation as a micromanagement tool, and user satisfaction with system functionality. Based on these results several important managerial implications for the adoption of a sales force automation system are suggested
Sale Force Automation Systems: The Correspondence Between The Perception Of Productivity Gains And The Perception Of Management Control Among Salespeople
Sales force automation (SFA) technologies have many apparent benefits, but the adoption of SFA systems often fails because the sales force holds poor perceptions of these technologies. Understanding how these perceptions affect adoption of SFA systems is important because negative perceptions held by the sales force can often adversely influence the successful adoption and implementation of such systems. This paper examines how the sales forceâs perceptions of productivity gains resulting from the adoption of an SFA system can be affected by their corresponding  perception of the SFA system as a tool employed by upper-level management to more closely manage the activities of the sales force. The results are based on a national survey of 1,657 salespeople. The findings indicate a negative relationship between salespeopleâs perceptions of the potential gains associated with the adoption of an SFA system and their corresponding perception of the use of the system by upper-level management to more closely manage the activities of the sales force
The Mount Perkins block, northwestern Arizona: An exposed cross section of an evolving, preextensional to synextensional magmatic system
This is the published version. Reuse is subject to Society of Exploration Geophysicists terms of use and conditions.The steeply tilted Mount Perkins block, northwestern Arizona, exposes a cross section of a magmatic system that evolved through the onset of regional extension. New 40Ar/39Ar ages of variably tilted (0â90°) volcanic strata bracket extension between 15.7 and 11.3 Ma. Preextensional intrusive activity included emplacement of a composite Miocene laccolith and stock, trachydacite dome complex, and east striking rhyolite dikes. Related volcanic activity produced an âŒ18â16 Ma stratovolcano, cored by trachydacite domes and flanked by trachydacite-trachyandesite flows, and âŒ16 Ma rhyolite flows. Similar compositions indicate a genetic link between the stratovolcano and granodioritic phase of the laccolith. Magmatic activity synchronous with early regional extension (15.7â14.5 Ma) generated a thick, felsic volcanic sequence, a swarm of northerly striking subvertical rhyolite dikes, and rhyolite domes. Field relations and compositions indicate that the dike swarm and felsic volcanic sequence are cogenetic. Modes of magma emplacement changed during the onset of extension from subhorizontal sheets, east striking dikes, and stocks to northerly striking, subvertical dike swarms, as the regional stress field shifted from nearly isotropic to decidedly anisotropic with an east-west trending, horizontal least principal stress. Preextensional trachydacitic and preextensional to synextensional rhyolitic magmas were part of an evolving system, which involved the ponding of mantle-derived basaltic magmas and ensuing crustal melting and assimilation at progressively shallower levels. Major extension halted this system by generating abundant pathways to the surface (fractures), which flushed out preexisting crustal melts and hybrid magmas. Remaining silicic melts were quenched by rapid, upper crustal cooling induced by tectonic denudation. These processes facilitated eruption of mafic magmas. Accordingly, silicic magmatism at Mount Perkins ended abruptly during peak extension âŒ14.5 Ma and gave way to mafic magmatism, which continued until extension ceased
Detection of potentially toxic metals by SERS using salen complexes
Surfaced enhanced Raman scattering (SERS) can discriminate between metal complexes due to the characteristic âspectral fingerprintsâ obtained. As a result, SERS has the potential to develop relatively simple and sensitive methods of detecting and quantifying a range of metal ions in solution. This could be beneficial for the environmental monitoring of potentially toxic metals (PTMs). Here, salen (C16H16N2O2) was used as a ligand to form complexes of Ni(II), Cu(II), Mn(II) and Co(II) in solution. The SERS spectra showed characteristic spectral differences specific to each metal complex, thus allowing the identification of each of these metal ions. This method allows a number of metal ions to be detected using the same ligand and an identical preparation procedure. The limit of detection (LOD) was determined for each metal ion, and it was found that Ni(II), Cu(II) and Mn(II) could be detected below the WHOâs recommended limits in drinking water at 1, 2 and 2 ”g L-1, respectively. Co(II) was found to have an LOD of 20 ”g L-1, however no limit has been set for this ion by the WHO as the concentration of Co(II) in drinking water is generally <1-2 ÎŒg L-1. A contaminated water sample was also analysed where Mn(II) was detected at a level of 800 ”g L-1
Ratiometric sensing of fluoride ions using Raman spectroscopy
Ratiometric Raman spectroscopy represents a novel sensing approach for the detection of fluoride anions based on alkyne desilylation chemistry. This method enables rapid, anion selective and highly sensitive detection of fluoride in a simple paper-based assay format using a portable Raman spectrometer
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