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Objective Stereoelectroencephalography (sEEG) is an intracranial encephalography method of expanding use. The need for increased epilepsy surgery access has led to the consideration of sEEG adoption by new or expanding surgical epilepsy programs. Data regarding safety and efficacy are uncommon outside of high‐volume, well‐established centers, which may be less applicable to newer or low‐volume centers. The objective of this study was to add to the sEEG outcomes in the literature from the perspective of a rapidly expanding center. Methods A retrospective chart review of consecutive sEEG cases from January 2016 to December 2019 was performed. Data extraction included demographic data, surgical data, and outcome data, which pertinently examined surgical method, progression to therapeutic procedure, clinically significant adverse events, and Engel outcomes. Results One hundred and fifty‐two sEEG procedures were performed on 131 patients. Procedures averaged 10.5 electrodes for a total of 1603 electrodes. The majority (84%) of patients progressed to a therapeutic procedure. Six clinically significant complications occurred: three retained electrodes, two hemorrhages, and one failure to complete investigation. Only one complication resulted in a permanent deficit. Engel 1 outcome was achieved in 63.3% of patients reaching one‐year follow‐up after a curative procedure. Significance New or expanding epilepsy surgery centers can appropriately consider the use of sEEG. The complication rate is low and the majority of patients progress to therapeutic surgery. Procedural safety, progression to therapeutic intervention, and Engel outcomes are comparable to cohorts from long‐established epilepsy surgery programs.

Increases in oil sands mining operations in the Athabasca oil sands region have resulted in increased concentrations of polycyclic aromatic compounds (PACs) and heavy metals in aquatic systems located near surface mining operations. In the present study, sediment cores were collected from 3 lakes with varying proximity to surface mining operations to determine the differences in PAC concentrations. Sediment cores were separated into 2 sections-current mining (top; 2000-2017) and premining (bottom; pre-1945)-and extracts were prepared for in vitro screening using a well-established chicken embryonic hepatocyte (CEH) assay. Concentrations and composition of PACs varied between sites, with the highest ∑PACs in Saline Lake, 5 km from an active oil sands mine site. The proportion of alkylated PACs was greater than that of parent PACs in the top sediment sections compared with the bottom. Ethoxyresorufin-O-deethylase activity in CEH permitted the ranking of lake sites/core sections based on an aryl hydrocarbon receptor-mediated end point; mean median effect concentration values were lowest for the top cores from Saline Lake and another near-mining operations lake, referred to as WF1. A ToxChip polymerase chain reaction (PCR) array was used to evaluate gene expression changes across 43 target genes associated with numerous toxicological pathways following exposure to top and bottom sediment core extracts. The 2 study sites with the greatest ∑PAC concentrations (Saline Lake and WF1) had the highest gene expression alterations on the ToxChip PCR array (19 [top] and 17 [bottom]/43), compared with a reference site (13 [top] and 7 [bottom]/43). The avian in vitro bioassay was useful for identifying the toxicity of complex PAC extracts associated with variably contaminated sediment cores, supporting its potential use for hotspot identification and complex mixture screening. EnvironToxicol Chem 2021;40:1883-1893. © 2021 SETAC.

Seabird population size is intimately linked to the physical, chemical, and biological processes of the oceans. Yet, the overall effects of long-term changes in ocean dynamics on seabird colonies are difficult to quantify. Here, we used dated lake sediments to reconstruct ~10,000-years of seabird dynamics in the Northwest Atlantic to determine the influences of Holocene-scale climatic oscillations on colony size. On Baccalieu Island (Newfoundland and Labrador, Canada)-where the world's largest colony of Leach's storm-petrel (Hydrobates leucorhous Vieillot 1818) currently breeds-our data track seabird colony growth in response to warming during the Holocene Thermal Maximum (ca. 9000 to 6000 BP). From ca. 5200 BP to the onset of the Little Ice Age (ca. 550 BP), changes in colony size were correlated to variations in the North Atlantic Oscillation (NAO). By contrasting the seabird trends from Baccalieu Island to millennial-scale changes of storm-petrel populations from Grand Colombier Island (an island in the Northwest Atlantic that is subjected a to different ocean climate), we infer that changes in NAO influenced the ocean circulation, which translated into, among many things, changes in pycnocline depth across the Northwest Atlantic basin where the storm-petrels feed. We hypothesize that the depth of the pycnocline is likely a strong bottom-up control on surface-feeding storm-petrels through its influence on prey accessibility. Since the Little Ice Age (LIA), the effects of ocean dynamics on seabird colony size have been altered by anthropogenic impacts. Subsequently, the colony on Baccalieu Island grew at an unprecedented rate to become the world's largest resulting from favorable conditions linked to climate warming, increased vegetation (thereby nesting habitat), and attraction of recruits from other colonies that are now in decline. We show that although ocean dynamics were an important driver of seabird colony dynamics, its recent influence has been modified by human interference.

Recently, cooperative relaying techniques have been integrated into spectrum-sharing systems in an effort to yield higher spectral efficiency. Many investigations on such systems have assumed that the channel state information between the secondary transmitter and primary receiver used to calculate the maximum allowable transmit secondary user transmit power to limit the interference is known to be perfect. However, because of feedback delay from the primary receiver or the time-varying properties of the channel, the channel information may be outdated, which is an important scenario to cognitive radio systems. In this paper, we investigate the impact of outdated channel state information for relay selection on the performance of partial relay selection with amplify and forward in underlay spectrum-sharing systems. We begin by deriving a closed-form expression for the outage probability of the secondary network in a Rayleigh fading channel along with peak received interference power constraint and maximum allowable secondary user transmit power. We also provide a closed-form expression for the average bit-error rate of the underlying system. Moreover, we present asymptotic expressions for both the outage probability and average bit-error rate in the high signal-to-noise ratio regime that reveal practical insights on the achievable diversity gain. Finally, we confirm our results through comparisons with computer simulations. Copyright © 2016 John Wiley & Sons, Ltd.

Summary 1. Size and age are fundamental organismal traits, and typically, both are good predictors of mortality. For many species, however, size and age predict mortality in ontogenetically opposing directions. Specifically, mortality due to predation is often more intense on smaller individuals whereas mortality due to senescence impacts, by definition, on older individuals. 2. When size-based and age-based mortality are independent in this manner, modelling mortality in both traits is often necessary. Classical approaches, such as Leslie or Lefkovitch matrices, usually require the model to infer the state of one trait from the state of the other, for example by assuming that explicitly modelled age (or stage) class structure provides implicit information on underlying size-class structure, as is the case in many species. 3. However, the assumption that one trait informs on the other is challenged when size and age are decoupled, as often occurs in invertebrates, amphibians, fish, reptiles and plants. In these cases, age-structured models may perform poorly at capturing size-based mortality, and vice versa. 4. We offer a solution to this dilemma, relaxing the assumption that class structure in one trait is inferable from class structure in another trait. Using empirical data from a reef fish, Sparisoma viride (Scaridae), we demonstrate how an individual-based model (IBM) can be implemented to model mortality as explicit, independent and simultaneous functions of individual size and age – an approach that mimics the effects of mortality in many wild populations. By validating this ‘multitrait IBM’ against three independent lines of empirical data, we determine that the approach produces more convincing predictions of size-class structure, longevity and post-settlement mortality for S. viride than do the trait-independent or single-trait mortality models tested. 5. Multitrait IBMs also allow trait-based mortality to be modelled either additively or multiplicatively, and individual variability in growth rates can be accommodated. Consequently, we propose that the approach may be useful in fields that may benefit from disentangling, or investigating interactions among, size-based and age-based demographic processes, including comparative demography (e.g. life-history consequences of resource patchiness) and conservation biology (e.g. impacts of invasive predators on size structure but not life span of natives).

Permafrost-supported peatlands near the southern limit of permafrost are experiencing dramatic landscape changes as a result of recent climate warming, which have the potential to impact aquatic ecosystems through changes in terrestrial run-off. Our objectives were to determine how terrestrial organic matter inputs to aquatic ecosystems in the southern Northwest Territories (Canada) changed as a result of peat subsidence, and whether terrestrial organic matter can be linked to sedimentary mercury. To accomplish this, we analyzed lipid biomarkers, lignin-derived phenols, and other geochemical proxies in sediment cores from two lakes (KAK-1 and TAH-7) affected by recent peat subsidence. Both lakes experienced substantial shifts in organic matter proxies through time, but the trajectory of change differed, reflecting local heterogeneity in hydrological setting and other environmental factors. In KAK-1, recent peat subsidence corresponded to a decrease in lignin-derived phenol yield, increased inferred lignin oxidation, and δ15N depletion. In TAH-7, peat subsidence was likely initiated by a local forest fire, and resulted in an increase in the n-alkanol ratio C30/(C30 + C28) (consistent with a warmer, wetter climate), lignin-derived phenol yield (mainly syringyls), and δ13C depletion. In TAH-7, total mercury inputs were positively correlated to terrestrial carbon inputs, suggesting allochthonous carbon is an important vector for mercury transport to the lake. In both lakes, an increase in the C23/(C23 + C29) n-alkane ratio was observed and suggests increased organic matter input from Sphagnum mosses. Our results demonstrate how terrestrial landscape changes occurring as a result of peat subsidence can influence carbon accumulation in aquatic ecosystems in discontinuous permafrost zones.

Professional development is the key to curriculum-based reform, yet there is little empirical evidence upon which to base decisions of design or implementation of training and development programmes. This study examined the training and development needs of Ghana’s polytechnic teachers in an existing curriculum reform scenario as they became involved in curriculum design. Forty-four teachers and four heads of mechanical engineering departments and representatives of the leadership of four polytechnics granted comprehensive interviews and responded to questionnaires. Findings revealed that updating subject knowledge through industrial attachments was a major training and development need for teachers. Teachers indicated that they were keen to get more involved in curriculum design and argued for their subject knowledge to be improved to give them the confidence to do so. The results of the study suggest higher education teachers have training and development needs in relation to effective curriculum design and implementation. It is proposed that polytechnic-industry links are strengthened and that teachers should draw on teamwork to plan and undertake industrial attachments.

Summary Purpose: We report a multicenter, double-blind, randomized trial of bilateral stimulation of the anterior nuclei of the thalamus for localization-related epilepsy. Methods: Participants were adults with medically refractory partial seizures, including secondarily generalized seizures. Half received stimulation and half no stimulation during a 3-month blinded phase; then all received unblinded stimulation. Results: One hundred ten participants were randomized. Baseline monthly median seizure frequency was 19.5. In the last month of the blinded phase the stimulated group had a 29% greater reduction in seizures compared with the control group, as estimated by a generalized estimating equations (GEE) model (p = 0.002). Unadjusted median declines at the end of the blinded phase were 14.5% in the control group and 40.4% in the stimulated group. Complex partial and “most severe” seizures were significantly reduced by stimulation. By 2 years, there was a 56% median percent reduction in seizure frequency; 54% of patients had a seizure reduction of at least 50%, and 14 patients were seizure-free for at least 6 months. Five deaths occurred and none were from implantation or stimulation. No participant had symptomatic hemorrhage or brain infection. Two participants had acute, transient stimulation-associated seizures. Cognition and mood showed no group differences, but participants in the stimulated group were more likely to report depression or memory problems as adverse events. Discussion: Bilateral stimulation of the anterior nuclei of the thalamus reduces seizures. Benefit persisted for 2 years of study. Complication rates were modest. Deep brain stimulation of the anterior thalamus is useful for some people with medically refractory partial and secondarily generalized seizures.

Many have demonstrated that anadromous Pacific salmon are significant vectors of nutrients from the ocean to freshwaters. Recently. however, it has been recognized that salmon spawners also input significant quantities of contaminants. The objectives of this paper are to delineate the extent to which salmon-derived nutrients are integrated into the freshwater food web using delta(15)N and delta(13)C and to assess the influence of the salmon pathway in the accumulation of contaminants in rainbow trout (Oncorhynchus mykiss). We found that the delta(15)N and delta(13)C of food web components were related positively and significantly to sockeye salmon (Oncorhynchus nerka) spawner density. Contaminant concentrations in rainbow trout also positively and significantly were related to sockeye salmon spawner density. These data suggest that the anadromous salmon nutrient and contaminant pathways are related and significantly impact the contaminant burden of resident fish.

Even though it has been established that the incorporation of computers into the teaching and learning process enhances student performance, the underlying mechanisms through which this is accomplished have been largely unexplored. The present study aims to shed light on this issue. Two groups of 10 secondary school students were tutored by their geography teacher in how to solve correlational problems. Students in the one group used paper and pencil while students in the other group used a computer spreadsheet. All tutorials were videotaped, transcribed verbatim, and subsequently all transcripts were segmented and coded. The mean frequencies for teacher and student behaviours between the two conditions were then compared. Results indicated that teacher behaviour in the two conditions differed in terms of error feedback, factual and conceptual questions asked, regulation of students, and task management. Regarding student behaviours, the findings showed that the two conditions differed in terms of task engagement, goal setting, and explanations given. On the basis of these findings the issue of mechanisms is discussed and three main implications for the teaching and learning practice are drawn.

Concentrations of DDT and its metabolites were measured in water, plants, invertebrates, and fish from lagoons in the Okavango Delta, Botswana (Africa), where DDT has been used for approximately 50 years. The sampling area was sectioned to distinguish spraying for malaria and for African sleeping sickness. Average concentrations of total DDT (sum of DDT and its metabolites) in the Okavango ranged from 0.009 ng/L in water to 18.76 ng/g wet weight in fish. These levels are approximately 1% of those found in piscivorous fish from temperate North America. The dichlorodiphenyl ethylene (DDE) metabolite was the most abundant fraction of total DDT. Although total DDT concentrations were higher in areas treated for malaria than areas treated for sleeping sickness, these concentrations were likely driven by factors other than the historic application of the pesticide. Equilibration with air concentrations is the most likely explanation for these levels. Since the mean annual temperature exceeds the temperature of vaporization of DDT, this research points to the need for reliable transport models. Our results showed that total DDT concentration in fish was best explained by lipid content of the fish and trophic position inferred by delta15N, regardless of DDT application history in those areas. The reservoir above Gaborone Dam, an area downstream of the Okavango but where DDT had not been used, was sampled to compare total DDT levels to the treated areas. The two species (a herbivorous threespot talapia and the omnivorous sharptooth catfish) from Gaborone had levels higher than those found in the Okavango Delta, but these differences can again be explained using trophic position inferred by delta15N rather than by fish size or location.

Samples of spruce needles, snowpack, and sediment were analyzed in the area around the Alberta Special Waste Treatment Centre (ASWTC) near Swan Hills, Canada, in 1997 and 1998, following a major accidental release of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in October 1996. The PCB concentrations in spruce needles and snow were mostly elevated to the east of the plant and contained congeners that were not present at upwind or distant sites. Several years of annual vegetation monitoring data indicated that PCB emissions increased prior to the reported accident. Within 3 km of the plant, there was a predominance of higher chlorinated congeners penta-, hexa-, hepta-, and octachlorobiphenyls in white spruce (Picea glauca) needles and snow. Polychlorinated biphenyl congener patterns varied seasonally in spruce needles, likely influenced by temperature effects on the volatilization and of particle-bound and vapor phase PCBs in the forest canopy. The similarity of deposition patterns in snow and needles in 1997 and 1998 suggested the PCBs in the surrounding area were derived by long-term fugitive releases of PCBs rather than an accidental release. In addition, hexachlorobenzene, a combustion by-product of chlorinated organics in waste incinerators, was not measured at elevated concentrations in spruce needles or snow east of the facility and, when detected, was not correlated with PCB concentrations. A radiometrically dated sediment core from nearby Chrystina Lake (AB, Canada) showed a gradual increase in annual PCB flux during the early years of operation of the ASWTC, followed by a higher PCB flux in 1997, indicating that the lake may have been directly contaminated by the accidental release.

The fluxes of several organochlorine compounds (OCs) to and from a high-altitude lake were calculated to determine the relative contributions of rainfall, snowfall, runoff, gas absorption and volatilization, sedimentation, and outflow. Runoff inputs, particularly from a glaciated catchment, and gas absorption were major sources of many OCs. Losses by volatilization, outflow, and sedimentation were also important transport pathways for most OCs. We observed a net deposition of hexachlorocyclohexanes (HCHs) and DDT to Bow Lake by gas exchange, whereas hexachlorobenzene, chlordanes, and most polychlorinated biphenyls were seen to volatilize to the air. The insecticide lindane (gHCH), widely applied across Canada as a seed dressing in early spring, was absorbed by Bow Lake in early summer but gradually equilibrated with water as the summer progressed. This was the result of lower concentrations of gHCH in air and rising air temperatures in late summer. Results indicate that glacially derived tributary inputs are dominant sources of persistent organic pollutants to these glacier-fed mountain lakes and that smaller contributions may derive from air-water gas exchange. This study highlights the importance of glacial sources of OCs to mountain lakes and corroborates recent evidence of OC contamination in glacially derived aquatic systems.

BACKGROUND The objective of this study was to evaluate long-term treatment outcome of definitive irradiation by using temporary interstitial implant and limited dose of external beam radiotherapy in treatment of localized prostate carcinoma. METHODS In total, 536 patients with biopsy-proven adenocarcinoma of the prostate, classification T1–T3, underwent staging pelvic lymph node dissection and brachytherapy delivering an average tumor dose of 30 grays (Gy), supplemented by external beam radiation therapy for an additional dose of 36 Gy delivered over 4 weeks. One hundred of 536 (18%) patients had pathologic D1 disease. A total of 181 patients had undergone transurethral prostatectomy before the treatment. Repeat prostate biopsy was performed on 132 patients 18 or more months after treatment. None of the patients received neoadjuvant or adjuvant hormone therapy. RESULTS Cumulative disease free survival (DFS) including biochemical DFS at 10 and 15 years for classification T1B,C was 78% and 72%; for T2A, 78% and 78%; for T2B,C, 68% and 66%; and for T3A–C, 45% and 45%, respectively. Cause specific survival for the entire group at 10 and 15 years was 89% and 87%, respectively. Severe complications occurred only in the early developmental phase of the study. CONCLUSIONS In univariate analysis, the clinical stage, histologic grade, pretreatment PSA level, lymph node status, and results of repeat posttreatment biopsy were all independently significant prognostic factors. However, the authors' study indicates that in multivariate analysis, only two factors emerged with statistical significance—the status of pelvic lymph nodes and the results of posttreatment biopsy. This signifies the importance of local tumor control to achieve ultimate cure and the importance of assessment of pelvic lymph nodes before definitive local therapy other than radical prostatectomy, especially in the high-risk group. Cancer 2001;92:2084–94. © 2001 American Cancer Society.

Sediment focusing is a process whereby water turbulence moves sedimented material from shallower to deeper zones of a lake. Sediment focusing occurs in lakes in both the erosional (coarse-grained sediments) and the transportational zone with the latter characterized by discontinuous sedimentation and resuspension. The zone of accumulation is diefined as the zone where sedimentation is final (i.e. no resuspension) and where there is no further sediment focusing. A geochemical tracer (Pb) was used to trace sediment focusing patterns in 12 lakes of different morphomctries. The area occupied by the zone of accumulation is predicted from the mean basin slope (a’,) with 86% of the variance explained. Only in large, exposed lakes in which turbulence from waves is more severe are the resulting sediment distributions more erratic. This study is the first to provide a general model of sc:diment focusing patterns among lakes. The study of lake-bottom dynamics has received attention in the contexts of sediment, contaminant, and eutrophication studies. The fact that sediments are major depositories for contaminants and nutrients has made them a focus for research in limnology. Also, because sediments provide a record of past events in lakes, an understanding of the manner in whllch sediments accumulate is essential for hindcasting. Interpretations of the historical record in sediments will be confounded if the record has been obscured by sediment resuspension. The term “sediment focusing” was coined by Likens and Davis ( 1975) to describe the resuspension of sediments in shallower zones by waves and water currents with subsequent transport to and settling in the deeper zones of lakes. Much of the work

A nontraumatic, nonretraction impression technique is presented which uses the fabrication of an acrylic resin shell from an interocclusal wax impression. A crucial step in the procedure is obtaining the complete finish line of the preparation within the resin. This tray, which is filled with an elastomeric impression material, is combined with a triple tray of the same material to provide all the necessary relationships to construct a crown or coping. This procedure is especially efficient for multiple abutments during fixed partial denture construction.

A pattern-matching approach provides a useful framework for developing and testing program theory.

A simplified method is described for achieving the purpose of the altered cast technique without the inherent laboratory problems of realignment of the metal framework on a modified cast and the extra time involved.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) as well as polychlorinated biphenyls (PCBs) were measured in white-tailed deer (Odocoileus virginianus) near a magnesium-refining facility in Quebec (Canada) known to be a source of chlorinated organic compounds to the area. We compared contaminant concentrations in deer caught one year before the start of magnesium production with those measured three years later. Total PCB concentrations were spatially uniform in deer before magnesium production, but after magnesium production began, concentrations were higher near the smelter and decreased with distance. Many of the midrange PCB homologues that bioconcentrate most in deer showed similar relationships. Concentrations of coplanar PCB congeners and cytochrome P4501A expression in deer liver were examined in a subset of the samples, and these also showed a significant inverse relationship with distance after magnesium production began. This pattern was not observed for PCDD/F concentrations in deer. The risk involved for the human population in consuming local deer meat was assessed by applying contaminant concentrations measured in the present study to Health Canada consumption guidelines. Contaminants in deer were not shown to pose a serious risk to the population, but the number of portions of deer from beyond 20 km that could be safely consumed was less restrictive than the number for deer from within a 5-km radius of the magnesium smelter.