The Tonkolili Iron Occurrence of Sierrra Leone: A Petrological Enigma?*

This paper endeavours to resolve, by petrological and mineralogical interrogations, the apparent puzzle being caused by the different names and classifications that have been assigned to the Tonkolili iron occurrence of Sierra Leone by different authors. The mineralogy and petrography of drill core samples of iron occurrences from Tonkolili district of Sierra Leoneare used to investigate the type of iron deposit, its environment of formation and classification. Three main rock types that host the Fe mineralisation have been identified as amphibolites, tuffs and mafic volcanic rocks. The amphibolites which crop out and are mapped on the surface are underlain by tuffs. Two types of tuffs were identified,namely as rhyolitic and crystal tuffs. The mafic volcanic rocks lie underneath the tuffs. The Fe mineralisations occur as bands and lenses in the tuff and are encountered from depths of 120 to 160 m in the drill holes. The Fe mineralisations which are mainly of Precambrian age are chemical sediments, contain about 55 % Fe and occur as mappable bands and lenses that have ironstone layers defining their top and bottom and thus satisfy Kimberly (1978)’s classification as “iron formation”.It is therefore the conclusion of this paper that with the realisation that the primary Fe mineral is magnetite rather than haematite and since there is an intimate association between the volcanic rocks and the Fe mineralisations, the Tonkolili Fe deposits can be classified as an Algoma type of Banded Iron Formation according to the classifications of James (1954) and definition of Cannon et al., (1986)

The geology of the gold deposits of Prestea gold belt of Ghana

This paper presents the geology of the gold deposits along the Prestea gold belt of Ghana to assist exploration work for new orebodies along the belt. Prestea district is the third largest gold producer in West Africa after Obuasi and Tarkwa districts (over 250 metric tonnes Au during the last century). The gold deposits are structurally controlled and occur in a deep-seated fault or fissure zone that is regarded as the ore channel. This structure, which lies at the contact between metavolcanic and metasedimentary rocks in Birimian rocks, is more open (and contains more quartz lodes) at the southern end around Prestea than at Bogoso to the north. The gold deposits consist of the Quartz Vein Type, (QVT) and the Disseminated Sulphide Type (DST). The QVT orebodies, which generally carry higher Au grades, lie within a graphitic gouge in the fissure zones whilst the DST is found mostly in sheared or crushed rocks near the fissure zones. Deposits were grouped into three in terms of geographic location and state of development; The deposits south of Prestea are the least developed but have been extensively explored by Takoradi Gold Company. Those at Prestea have been worked exclusively as underground mines on QVT orebodies by Prestea Goldfields Limited and its forerunners; Ariston and Ghana Main Reef companies until 1998 whilst the deposits north of Prestea, which were first worked as surface mines (on DST orebodies) by Marlu Mines up to 1952, were revived by Billiton Bogoso Gold in 1990. Bogoso Gold Limited, a subsidiary of Golden Star Resources, now runs the mines, which are currently working “Oxide ore” (the oxidised derivate of the DST ore) by surface operations in open cut mines at Bogoso and Prestea. Active exploration is presently underway to find extensions to the orebodies and extend the life of the mines. The summary of the special attributes of the deposits presented in this paper may be useful in re-evaluation of the orebodies.

Characteristics of an insert product placement as a part of marketing communication

The paper defined saturation of an insert product placement as a part of marketing communication. Product placement is known as a modern tool of marketing communication and so that product placement and its types and forms are not so casual used in the Czech Republic as in other parts of the world. The mentioned issues are explained from the perspectives of three groups: TV studios experts, directors and producers and other experts (media agencies and advertisers). Types and forms of this marketing communication tool as well as options of its utilization are also mentioned in the paper. The Czech Republic market where product placement occurs is very small - only few television companies. The primary aim of the paper is to identify the intensity of two essential areas expressing product placement using - natural (non-invasive) insert and contrived (invasive) insert. Moreover, conflicting interests of the interested parties (advertiser - ordering party, producer and television) are observed in the paper too. The last issue discussed in this paper is to what extent the degree of product placement implementation can affect the script and what impact on quality and specifics of an audiovisual work can this script modification have. © 2014 , Mendel University of Agriculture and Forestry Brno. All rights reserved

Radiation Safety in the Treatment of Patients with Thyroid Diseases by Radioiodine 131I: Practice Recommendations of the American Thyroid Association

Background: Radiation safety is an essential component in the treatment of patients with thyroid diseases by 131I. The American Thyroid Association created a task force to develop recommendations that would inform medical professionals about attainment of radiation safety for patients, family members, and the public. The task force was constituted so as to obtain advice, experience, and methods from relevant medical specialties and disciplines. Methods: Reviews of Nuclear Regulatory Commission regulations and International Commission on Radiological Protection recommendations formed the basic structure of recommendations. Members of the task force contributed both ideas and methods that are used at their respective institutions to aid groups responsible for treatments and that instruct patients and caregivers in the attainment of radiation safety. There are insufficient data on long-term outcomes to create evidence-based guidelines. Results: The information was used to compile delineations of radiation safety. Factors and situations that govern implementation of safety practices are cited and discussed. Examples of the development of tables to ascertain the number of hours or days (24-hour cycles) of radiation precaution appropriate for individual patients treated with 131I for hyperthyroidism and thyroid cancer have been provided. Reminders in the form of a checklist are presented to assist in assessing patients while taking into account individual circumstances that would bear on radiation safety. Information is presented to supplement the treating physician's advice to patients and caregivers on precautions to be adopted within and outside the home. Conclusion: Recommendations, complying with Nuclear Regulatory Commission regulations and consistent with guidelines promulgated by the National Council on Radiation Protection and Measurement (NCRP-155), can help physicians and patients maintain radiation safety after treatment with 131I of patients with thyroid diseases. Both treating physicians and patients must be informed if radiation safety, an integral part of therapy with 131I, is to be attained. Based on current regulations and understanding of radiation exposures, recommendations have been made to guide physicians and patients in safe practices after treatment with radioactive iodine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90492/1/thy-2E2010-2E0403.pd

Effect of Left Atrial Function Index on Late Atrial Fibrillation Recurrence after Pulmonary Vein Isolation

Background: Although the rates of catheter ablation (CA) for atrial fibrillation (AF) are rapidly increasing, there are few predictors of outcome to help inform appropriate patient selection for this procedure. Traditional echocardiographic measures of atrial structure do not significantly reclassify risk of AF recurrence over and above the clinical risk factors. Left Atrial Function Index (LAFI) is a rhythm-independent measure of atrial function. We hypothesized that baseline LAFI would relate to AF recurrence after CA. Methods: Pre-procedural echocardiograms from 170 participants, who underwent CA for AF and were enrolled in the UMMC AF Treatment Registry, were analyzed. LAFI was calculated by a previously validated formula. Primary outcome was late or clinically significant AF recurrence 3-12 months after CA. Baseline clinical, laboratory and echocardiographic variables were compared between the recurrence and non-recurrence groups. Results: Study participants were middle aged (60+/10 years) and had a moderate-to-severe burden of cardiovascular comorbidities. 78 participants (46%) experienced late AF recurrence. Mean LAFI was 0.26+/-0.18. In multivariate analysis, lower LAFI was independently associated with the risk of recurrence (0.23 in recurrence group vs 0.29 in non-recurrence group, p \u3c 0.01). Predictive value of LAFI for AF recurrence was similar to CHADS2 score (c-statistic 0.60 vs 0.58, p 0.76). In subgroup of patients with persistent AF, LAFI predicted AF recurrence more strongly than CHADS2 score (c-statistic: 0.79 vs 0.58, p 0.02). Conclusions: In our cohort of 170 participants with AF undergoing index CA ablation, we observed that LAFI related to late AF recurrence after CA, independent of the traditional risk factors. Since LAFI can be calculated from almost any traditional echocardiographic recording, our findings suggest that LAFI may help guide therapeutic decision-making regarding application of CA, particularly among challenging patients with symptomatic persistent AF